FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
AND
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION
HYBRID DRIVETRAIN FOR A VEHICLE AND METHOD OF CONTROLLING DRIVE MODES IN HYBRID DRIVETRAIN
APPLICANT(S)
TATA MOTORS LIMITED
an Indian company
Bombay House, 24 Homi Mody Street,
Hutatma Chowk, Mumbai 400 001,
Maharashtra, India.
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed.

TECHNICAL FIELD OF THE INVENTION
[001] This disclosure relates generally to hybrid vehicles, and more
particular to a hybrid drivetrain for a vehicle and method of controlling drive modes
5 in the hybrid drivetrain.
BACKGROUND OF THE INVENTION
[002] Hybrid vehicles utilize a combination of two or more distinct power
10 sources for propulsion. Typically, these power sources include an internal
combustion (IC) engine and an electric motor. The goal of hybrid vehicles is to
achieve improved fuel efficiency and reduced emissions compared to traditional,
solely gasoline-powered vehicles.
15 [003] Typically, the drivetrain of the hybrid vehicles includes an epicyclic
gear assembly which further includes a sun gear and a set of planetary gears. However, the drivetrain of these hybrid vehicles involve the integration of the IC engine, the electric motor, and a complex control system. Coordinating the operation of these components seamlessly poses engineering challenges, requiring
20 sophisticated control algorithms to optimize efficiency and performance. Further,
coordinating the transitions between the two power sources and ensuring smooth operation can be complex. Additionally, managing the handoff between electric and gasoline modes introduces challenges in terms of efficiency and reliability. Furthermore, there exist challenges in implementing regenerative braking without
25 compromising braking performance.
[004] Therefore, there is need for a cost-effective solution that ensures efficiency and performance, as well as application of ideal gear ratios for various drive modes in hybrid vehicles. 30

SUMMARY OF THE INVENTION
[005] In an embodiment, a hybrid drivetrain is disclosed. The hybrid
drivetrain may include a first epicyclic gear assembly that may include a first sun
5 gear and a first set of planetary gears. Each of the first set of planetary gears may
be engaged with the first sun gear. The hybrid drivetrain may further include a second epicyclic gear assembly that may include a second sun gear and a second set of planetary gears. Each of the second set of planetary gears may be engaged with the second sun gear. The hybrid drivetrain may further include a ring gear
10 engaged with each of the first set of planetary gears and the second set of planetary
gears. The hybrid drivetrain may further include a planet carrier assembly coupled to a set of wheels of a vehicle to drive the set of wheels. The first set of planetary gears and the second set of planetary gears may be rotatably coupled to the planet carrier assembly. The hybrid drivetrain may further include a plurality of clutches
15 configured to selectively couple the first sun gear and the ring gear with a first
power source, and selectively couple the first sun gear and the second sun gear with a second power source, to obtain a plurality of drive modes of the vehicle. In each of the plurality of drive modes, the vehicle may be driven by the first power source, or the second power source, or a combination thereof.
20
[006] In another embodiment, a system for controlling drive modes in a hybrid drivetrain of a vehicle is disclosed. The system may include a first epicyclic gear assembly 102 that may include a first sun gear and a first set of planetary gears. Each of the first set of planetary gears may be engaged with the first sun gear. The
25 system may further include a second epicyclic gear assembly that may include a
second sun gear and a second set of planetary gears. Each of the second set of planetary gears may be engaged with the second sun gear. The system may further include a ring gear engaged with each of the first set of planetary gears and the second set of planetary gears. The system may further include a planet carrier
30 assembly coupled to a set of wheels of the vehicle to drive the set of wheels. The
first set of planetary gears and the second set of planetary gears may be rotatably

coupled to the planet carrier assembly. The system may further include a plurality
of clutches a plurality of actuators. Each of the plurality of actuators may engage
with one of the plurality of clutches to change a configuration of the respective
clutch between an engaged configuration and an unengaged configuration. The
5 system may further include a processor and a memory communicatively coupled
with the processor. The memory stores processor-executable instructions, which, on execution by the processor, cause the processor to receive one or more parameters associated with the vehicle corresponding to a current running state of the vehicle. The processor-executable instructions further cause the processor to
10 select a drive mode from a plurality of drive modes, based on the one or more
parameters, and trigger at least one of the plurality of actuators to configure the respective clutches of the plurality of clutches in the engaged configuration, to selectively couple the first sun gear and the ring gear with a first power source, or selectively couple the first sun gear and the second sun gear with a second power
15 source, to thereby obtain a drive mode of the plurality of drive modes of the vehicle.
In each of the plurality of drive modes, the vehicle is driven by the first power source, or the second power source, or a combination thereof.
[007] In another embodiment, a method of controlling drive modes in a
20 hybrid drivetrain is disclosed. The method may include receiving one or more
parameters associated with a vehicle corresponding to a current running state of the
vehicle, and selecting a drive mode from a possible of drive modes, based on the
one or more parameters. The method may further include triggering at least one of
a plurality of actuators to configure respective clutches of a plurality of clutches in
25 an engaged configuration, to selectively couple a first sun gear and a ring gear with
a first power source, and selectively couple the first sun gear and a second sun gear
with a second power source, to thereby achieve a plurality of drive modes. The first
sun gear may be coupled with a first set of planetary gears of a first epicyclic gear
assembly. The second sun gear may be coupled with a second set of planetary gears
30 of a second epicyclic gear assembly. A planet carrier assembly may be coupled to
a set of wheels of the vehicle, and the first set of planetary gears and the second set

of planetary gears may be rotatably coupled to the planet carrier assembly. The ring gear may be engaged with each of the first set of planetary gears and the second set of planetary gears.
5 [008] In yet another embodiment, a vehicle is disclosed that may include a
set of drive wheels to impart a drive to the vehicle, a first power source, a second power source, and a hybrid drivetrain configured to selectively couple at least one of the first power source and the second power source with the set of drive wheels. The hybrid drivetrain may include a first epicyclic gear assembly that may include
10 a first sun gear and a first set of planetary gears. Each of the first set of planetary
gears may be engaged with the first sun gear. The hybrid drivetrain may further include a second epicyclic gear assembly that may include a second sun gear and a second set of planetary gears. Each of the second set of planetary gears engaged with the second sun gear. The hybrid drivetrain may further include a ring gear
15 engaged with each of the first set of planetary gears and the second set of planetary
gears, and a planet carrier assembly coupled to the set of wheels. The first set of planetary gears and the second set of planetary gears may be rotatably coupled to the planet carrier assembly. The hybrid drivetrain may further include a plurality of clutches configured to selectively couple the first sun gear and the ring gear with
20 the first power source, and selectively couple the first sun gear and the second sun
gear with the second power source, to obtain a plurality of drive modes of the vehicle. In each of the plurality of drive modes, the vehicle may be driven by the first power source, or the second power source, or a combination thereof.
25 BRIEF DESCRIPTION OF THE DRAWINGS
[009] The accompanying drawings, which are incorporated in and constitute
a part of this disclosure, illustrate exemplary embodiments and, together with the
description, serve to explain the disclosed principles.
30 [010] FIG. 1 is a schematic diagram of a hybrid drivetrain, in accordance
with some embodiments of the present disclosure.

[011] FIGs. 2A-2C illustrate magnified views of section A, section B, and section C, respectively, of the hybrid drivetrain of FIG. 1, in accordance with some embodiments.
[012] FIGs. 3A-3C depict Table-1, Table-2, and Table-3 showing example
5 gear ratios available in the MGU drive modes, ICE drive modes, and hybrid drive
modes, respectively, in accordance with some embodiments.
[013] FIGs. 4A-4C illustrate schematic diagrams of the hybrid drivetrain
being configured in a first MGU drive mode, a second MGU drive mode, and a
third MGU drive mode, respectively, in accordance with some embodiments.
10 [014] FIGs. 5A-5D illustrate schematic diagrams of the hybrid drivetrain
being configured in a first ICE drive mode, a second ICE drive mode, a third ICE drive mode, and a fourth ICE drive mode respectively, in accordance with some embodiments.
[015] FIGs. 6A-6D illustrate schematic diagrams of the hybrid drivetrain
15 being configured in a first hybrid drive mode, a second hybrid drive mode, a third
hybrid drive mode, and a fourth hybrid drive mode respectively, in accordance with some embodiments.
[016] FIG. 7 illustrates schematic diagrams of the hybrid drivetrain being
configured in a start-and-idle drive mode, in accordance with some embodiments.
20 [017] FIG. 8 illustrates schematic diagrams of the hybrid drivetrain being
configured in an idle mode, in accordance with some embodiments.
[018] FIG. 9 is a schematic diagram of a system for controlling drive modes in the hybrid drivetrain of a vehicle, in accordance with some embodiments.
[019] FIG. 10 illustrates a flowchart of a method of controlling drive modes
25 in the hybrid drivetrain, in accordance with some embodiments.
[020] FIG. 11 illustrates a flowchart of another method of controlling drive modes in the hybrid drivetrain, in accordance with some embodiments.
[021] FIG. 12 illustrates a flowchart of a yet another method of controlling drive modes in the hybrid drivetrain, in accordance with some embodiments. 30

DETAILED DESCRIPTION OF THE DRAWINGS
[022] Exemplary embodiments are described with reference to the
accompanying drawings. Wherever convenient, the same reference numbers are
5 used throughout the drawings to refer to the same or like parts. While examples and
features of disclosed principles are described herein, modifications, adaptations,
and other implementations are possible without departing from the spirit and scope
of the disclosed embodiments. It is intended that the following detailed description
be considered as exemplary only, with the true scope and spirit being indicated by
10 the following claims. Additional illustrative embodiments are listed below.
[023] The present disclosure is about a hybrid drivetrain that may be used in modern hybrid vehicles. The hybrid drivetrain uses two epicyclic gear assemblies along with a ring gear, a planet carrier, and a plurality of clutches to achieve a
15 plurality of drive modes. The plurality of drive modes may include a set of Motor
Generator Unit (MGU) modes (i.e. three MGU modes), a set of internal combustion engine (ICE) modes (i.e. four ICE modes), and a set of hybrid modes (four hybrid modes). Along with that the plurality of drive modes may include a start-and-idle drive and an idle mode. The three MGU modes may be used for initial acceleration
20 from standstill, whereas three out of four ICE drive modes may be used for the
high-speed highway running.
[024] The hybrid drivetrain of the present disclosure overcomes the issues of high cost and ideal gear ratios for improved pure MGU top speed. The two
25 epicyclic gear assemblies have two degrees of freedom (DOF), which are
constrained by the IC engine connected to the ring gear, and the MGU connected to sun gear(s). Power from both the ICE and the MGU is transferred to the planet carrier and later can be used to manipulate the power supplied from the ICE by restricting the applied torque. The hybrid drivetrain, therefore, provides for
30 controlling (via the MGU) the output of the ICE for the most optimal drivability
and efficiency.

[025] Apart from the above, some alternate configuration may be possible.
For example, in one configuration, the ICE connects to the planet carrier, and the
MGU connects to the sun gear(s). In another configuration, the ICE connects to the
sun gear(s), and the MGU connects to the planet carrier. In another configuration,
5 the ICE connects to the ring gear, and the MGU connects to the planet carrier. In
yet another configuration, the ICE connects to the sun gear, and the MGU connects to the ring gear.
[026] Referring now to FIG. 1, a schematic diagram of a hybrid drivetrain
10 100 is illustrated, in accordance with some embodiments of the present disclosure.
The hybrid drivetrain 100 may include a first epicyclic gear assembly 102. The first epicyclic gear assembly 102 may include a first sun gear 102A and a first set of planetary gears 102B. The first sun gear 102A may have gear teeth on its outer periphery. For example, the first set of planetary gears 102B may include three or
15 four planetary gears 102B, each having gear teeth on its outer periphery. Each of
the first set of planetary gears 102B may be engaged with the first sun gear 102A. The hybrid drivetrain 100 may further include a second epicyclic gear assembly 104 that may include a second sun gear 104A and a second set of planetary gears 104B. The second sun gear 104A may have gear teeth on its outer periphery. For
20 example, the second set of planetary gears 104B may include three or four planetary
gears, each having gear teeth on its outer periphery. Each of the second set of planetary gears 104B may be engaged with the second sun gear 104A, i.e. via the associated gear teeth. The hybrid drivetrain 100 may further include a ring gear 106 that may be engaged with each of the first set of planetary gears 102B and the
25 second set of planetary gears 104B, as shown in FIG. 1. The hybrid drivetrain 100
may further include a planet carrier assembly 108 that may be coupled to a set of wheels (not shown in FIG. 1) of a vehicle to drive the set of wheels. The first set of planetary gears 102B and the second set of planetary gears 104B may be rotatably coupled to the planet carrier assembly 108.
30

[027] The hybrid drivetrain 100 may further include a plurality of clutches
configured to selectively couple the first sun gear 102A and the ring gear 106 with
a first power source 110. The plurality of clutches may be further configured to
selectively couple the first sun gear 102A and the second sun gear 104A with a
5 second power source 112, to thereby obtain a plurality of drive modes of the
vehicle. It should be noted that in each of the plurality of drive modes, the vehicle
driven by either the first power source 110, or the second power source 112, or a
combination thereof. In some embodiments, the first power source 110 may be an
Internal Combustion Engine ICE, and the second power source 112 may be a Motor
10 Generator Unit (MGU).
[028] The hybrid drivetrain 100 may further include a first shaft 114A that may be coupled with the first sun gear 102A. The plurality of clutches may be configured to selectively couple the first sun gear 102A with the first power source
15 110 and the second power source 112, via the first shaft 114A. The hybrid drivetrain
100 may further include a second shaft 114B that may be coupled with the second sun gear 104A. The plurality of clutches may be configured to selectively couple the second sun gear 104A with the second power source 112, via the second shaft 114B. The hybrid drivetrain 100 may further include a third shaft 114C that may be
20 coupled with the ring gear 106. The plurality of clutches may be configured to
selectively couple the ring gear 106 with the first power source 110, via the third shaft 114C. In some embodiments, as shown in FIG. 1, the first shaft 114A, the second shaft 114B, and the third shaft 114C may be concentric.
25 [029] In particular, the plurality of clutches may include a first clutch C0
that may be configured to selectively couple the first sun gear 102A with the first power source. The plurality of clutches may further include a second clutch C1 that may be configured to selectively couple the ring gear 106 with the first power source 110. The plurality of clutches may further include a third clutch C2 that may
30 be configured to selectively fix rotation of the ring gear 106. The plurality of
clutches may further include a fourth clutch C3 that may be configured to

selectively fix rotation of the first sun gear 102A and the second sun gear 104A.
The plurality of clutches may further include a fifth clutch C4 that may be
configured to selectively couple the first sun gear 102A with the second power
source 112. The plurality of clutches may further include a sixth clutch C5 that may
5 be configured to selectively couple the second sun gear 104A with the second power
source 112. The hybrid drivetrain 100 is further explained in detail in conjunction with FIGs. 2A-2C.
[030] Referring now to FIGs. 2A-2C, magnified views of section A, section
10 B, and section C, respectively, of the hybrid drivetrain 100 of FIG. 1 are illustrated,
in accordance with some embodiments. As shown in FIG. 2A, the first clutch C0
and the second clutch C1 may be housed in a housing 202. In some embodiments,
the first power source 110 (i.e. the IC engine) may be coupled to the housing 202,
via a first interface 204. The housing 202 may include one or more grooves to hold
15 outer clutch plates of the first clutch C0 and the second clutch C1. Inner clutch
plates of the first clutch C0 and the second clutch C1 may be connected to the first shaft 114A and the second shaft 114B.
[031] As shown in FIG. 2B, the first shaft 114A may be connected to the
20 first sun gear 102A and the sixth clutch C5. The second shaft 114B may be further
connected to the ring gear 106. As mentioned above, the first clutch C0 may be
applied to connect or disconnect the first sun gear 102A with the first power source
110, and the second clutch C1 may be applied to connect or disconnect the ring gear
106 with the first power source 110. The ring gear 106 may be common to both the
25 first epicyclic gear train 102 and the second epicyclic gear train 104. Further, the
planet carrier assembly 108 may be common to both the first epicyclic gear train
102 and the second epicyclic gear train 104. It should be noted that the radius of the
first sun gear 102A and first set of planetary gears 102B may be different from
radius of the second sun gear 104A and second set of planetary gears 104B,
30 respectively. As a result, even with the common ring gear 106, gear ratios between
the output (through the planet carrier assembly 108) and the input (through either

the first sun gear 102A, the ring gear 106, the second sun gear 104A, or a combination of all of the above) can vary and, hence, multiple gear ratios can be realized.
5 [032] As shown in FIG. 2C, a 3-way clutch housing 206 may be used to
control the power flow from or to the second power source 112 (i.e. the MGU). The first shaft 114A may be common to both the housing 202 and the housing 206. The first shaft 114A may further connect with the first sun gear 102A. The second shaft 114B may be connected to the housing 206 via the fifth clutch C4. The other end
10 of the second shaft 114B may be connected to second sun gear 104A. As mentioned
above, the fifth clutch C4 may be applied to selectively couple the first sun gear 102A with the second power source 112, and the sixth clutch C5 may be applied to selectively couple the second sun gear 104A with the second power source 112. The fourth clutch C3 in the housing 206 may be used to control the restriction of
15 motion of the housing 206 itself, in some of the driving modes, as will be explained
in the subsequent sections of this disclosure.
[033] The first epicyclic gear train and the second epicyclic gear train 104 may have two degrees of freedom, which are constrained by the first power source
20 110 (connected to the ring gear 106) and the second power source 112 (connected
to the first sun gear 102A and the second sun gear 104A). Power from both the first power source 110 and the second power source 112 may be transferred to the planet carrier assembly 108 and can be later used to manipulate the power (supplied from the first power source 110 and the second power source 112) by restricting the
25 applied torque. As such, the hybrid drivetrain 100 provides for controlling the
output from the first power source 110 (i.e. the IC engine) for most optimal drivability and efficiency, which is controlled via the second power source 112 (i.e. the MGU).
30 [034] The hybrid drivetrain 100 of the present subject matter, by
implementing the two planetary gear arrangements - the first epicyclic gear

assembly 102 and the second epicyclic gear assembly 104 - overcomes the issues high cost and ideal ratio for an improved pure EV top speed.
[035] In some embodiments, four configurations of the hybrid drivetrain
5 100 are possible. In the first configuration, the first power source 110 connects to
the planet carrier assembly 108 and the second power source 112 connects to the first sun gear 102A and the second sun gear 104A. In the second configuration, the first power source 110 connects to the first sun gear 102A and the second sun gear 104A, and the second power source 112 connects to planet carrier assembly 108. In
10 the third configuration, the first power source 110 connects to the ring gear 106 and
the second power source 112 connects to planet carrier assembly 108. In the fourth configuration, the first power source 110 connects to the first sun gear 102A and the second sun gear 104A and the second power source 112 connects to ring gear 106.
15
[036] The hybrid drivetrain 100, when compared to conventional solutions, implements only a single second power source 112 (MGU) in comparison to two implemented in the conventional solutions. Further, by implementing two epicyclic gear trains (i.e. the first epicyclic gear assembly 102 and the second epicyclic gear
20 assembly 104), seven additional driving modes can be achieved. Further, the hybrid
drivetrain 100 provides for three pure EV modes, which are advantageous for the overall drivability. Furthermore, the gear ratios can be changed, as per the application and requirement. Moreover, high torque from the MGU drive mode can be used for city driving conditions provided a certain level of SoC is available,
25 thereby lowering the emissions without any compromise in drivability.
[037] In addition to providing the power to the wheels, the pure EV modes,
when working in reverse, provide three levels of regeneration braking– level-1 (L1)
regeneration braking, level-2 (L2) regeneration braking, and level-3 (L3)
30 regeneration braking. When the power flow is reversed, power from the wheels is
transferred to the battery via the second power source 112 (MGU) which then acts

as a generator. Further, level-3 regeneration braking may be used when coasting on
highways or when there is mild braking. Level-2 regeneration braking may be used
when going downhill or when the braking is 20-50%, or when coasting in city
conditions. Level-1 regeneration braking may be used when going downhill and
5 braking or when breaking is 50-80%. For 100% braking, conventional brakes may
be used with level-1 regeneration. Some example gear ratios available in the MGU drive modes are shown in Table 1, illustrated via FIG. 3A.
[038] The hybrid drivetrain 100 further provides for four pure engine
10 modes, having different gear ratios for a variety of driving conditions. The gear
ratios may be configured based on the requirements and application. The four pure engine modes may be similar to an automatic transmission with seamless shifting between different gears. The shifting can be controlled by automatic clutches, which may be further controlled by an ECU (refer, FIG. 9). The first power source
15 110 (IC engine) may not require a dedicated starter motor, as the second power
source 112 (MGU) can act as the starter and generator. Some example gear ratios available in the ICE drive modes are shown in Table 2, illustrated via FIG. 3B. The gear ratios are linked (i.e. dependent) on that of the gear ratio of the second power source 112 (MGU) as in pure EV modes. Hence, there is a trade-off between the
20 ratios between the second power source 112 and the first power source 110. The
four pure engine modes can be realized with the same powertrain configuration with the addition of clutches using the first epicyclic gear assembly 102 and the second epicyclic gear assembly 104. The maximum gear ratio in the pure engine mode may be limited to 1. However, the overdrive gear ratios may be available in hybrid
25 modes, described in the subsequent sections.
[039] The hybrid drivetrain 100 further provides for four hybrid modes, two
of which have fixed ratios with the combination of two MGU drive and two ICE
drive modes, respectively. The other two modes include an e-CVT mode in which
30 the second power source 112 (MGU) may be used to control the torque output and
the revolutions per minutes (RPM) of the first power source 110 (IC engine). The

second power source 112 may either provide the power or act as a generator to provide regeneration torque to the first power source 110, for the e-CVT functionality.
5 [040] It should be noted that shifting between the various drive modes may
be controlled by the plurality of clutches, via the ECU. The e-CVT mode may provide for infinite gear ratios between certain lower and upper limit values. As such, the effect of the e-CVT mode may be similar to a belt-driven CVT transmission –belt-driven CVT transmission includes a belt and pulley
10 arrangement; in the e-CVT mode, power transmission is controlled by varying the
inputs of the second power source 112 (which then controls one of the first epicyclic gear assembly 102 and the second epicyclic gear assembly 104. The e-CVT modes are responsible for the overdrive gear ratios for the IC engine for highway speeds (subject to certain level of minimum SoC left in the battery).
15
[041] The two e-CVT modes can be chosen, as per the suitability of efficiency and RPM conditions for both the MGU and IC engine. In the third hybrid mode, the gear ratio may vary from a maximum of 1.2 to about 0.6, with the constant engine RPM (for highest torque output) and varying the MGU speed to
20 vary the final drive speed. Similarly, in the fourth hybrid mode, the gear ratio varies
from a maximum of 1.67 to about 0.8, with the IC engine speed constant, and varying the MGU speed. This results in better control over the emissions and efficiency over the conventional gearbox arrangements. The four hybrid modes provide versatility to choose from the different driving modes. The hybrid modes
25 take into account the varying terrain conditions and the demand for power and
torque pertaining to different situations. Some example gear ratios available in the hybrid modes are shown in Table 3, illustrated via FIG. 3C.
[042] Therefore, a plurality of (eleven) drive modes can be achieved with
30 the hybrid drivetrain 100. These eleven drive modes cover almost every use case
during driving in different terrains. For example, a user has the option to choose

MGU drive modes and at the same time have the option to choose for ideal speeds in the IC engine drive modes. Further, regeneration torque can be used to control the speed ratio between the IC engine and final drive.
5 [043] The plurality of drive modes of the vehicle may include a set of MGU
drive modes. In particular, the set of MGU drive modes may include a first MGU
drive mode, a second MGU drive mode, and a third MGU drive mode. A gear ratio
associated with the second MGU drive mode may be greater than a gear ratio
associated with the third MGU drive mode. Further, a gear ratio associated with the
10 first MGU drive mode may be greater than the gear ratio associated with the second
MGU drive mode. The set of MGU drive modes are further explained in conjunction with FIGs. 4A-4C.
[044] FIG. 4A illustrates a schematic diagram of the hybrid drivetrain 100
15 being configured in the first MGU drive mode, in accordance with some
embodiments. The power flow in the first MGU drive mode is represented by the
dotted line in FIG. 4A. As shown in FIG. 4A, in the first MGU drive mode, the first
clutch C0 may be unengaged, and therefore, the first sun gear 102A may be
decoupled from the first power source 110. The second clutch C1 may be
20 unengaged, and therefore, the ring gear 106 may be decoupled from the first power
source 110. The third clutch C2 may be engaged, and as a result, the rotation of the
ring gear 106 may be fixed. The fourth clutch C3 may be unengaged, and therefore,
the rotation of the first sun gear 102A and the second sun gear 104A may not be
fixed (i.e. free to rotate). The fifth clutch C4 may be engaged, and therefore, the
25 first sun gear 102A may be coupled with the second power source 112. The sixth
clutch C5 may be unengaged, and therefore, the second sun gear 104A may be
decoupled from the second power source 112.
[045] As such, the first MGU drive mode is realized when the third clutch
30 C2 and the fifth C4 are engaged (refer, column “MGU only/Reverse/Downhill” in
Table 1 in FIG. 3A). The power flows from the MGU 112 (the terms “second power

source” and “MGU” may have been used interchangeably in the present disclosure) via the fifth clutch C4 which further connects to the second sun gear 104A and to the planet carrier assembly 108 of the second epicyclic gear assembly 104. The ring gear 106 may be fixed via the third clutch C2. The rotation of the second sun gear 5 104 A translates into the rotation of the planet carrier assembly 108, as the ring gear 106 is fixed. Equation (1) is the governing equation for speed ratio in the first MGU drive mode:
��= ��1∗��1
2∗(��1 + ��1)
… Equation (1)
10
[046] here, Np is angular speed of the planet carrier assembly 108; Ns1 is
angular speed of the second sun gear 104A; and Rs1 is radius of the second sun
gear 104 A.
15 [047] The above configuration can be used during reversing with the MGU
rotating in reverse direction. Further, the configuration can be used as level-1 regeneration braking, for the conditions when heavy braking is required or when going downhill. In such cases, the MGU 112 may act as a generator and charge the battery of the vehicle.
20
[048] FIG. 4B illustrates a schematic diagram of the hybrid drivetrain 100 being configured in the second MGU drive mode, in accordance with some embodiments. The power flow in the second MGU drive mode is represented by the dotted line in FIG. 4B. As shown in FIG. 4B, in the second MGU drive mode,
25 the first clutch C0 may be unengaged, and therefore, the first sun gear 102A may be decoupled from the first power source 110. The second clutch C1 may be unengaged, and therefore, the ring gear 106 may be decoupled from the first power source 110. The third clutch C2 may be engaged, and therefore, the rotation of the ring gear 106 may be fixed. The fourth clutch C3 may be unengaged, and therefore,
30 the rotation of the first sun gear 102A and the second sun gear 104A may not be

fixed (i.e. free to rotate). The fifth clutch C4 may be unengaged, and therefore, the first sun gear 102A may be decoupled from the second power source 112. The sixth clutch C5 may be engaged, and therefore, the second sun gear 104A may be coupled with the second power source 112. 5
[049] The second MGU drive mode may be realized when the third clutch C2 and the sixth clutch C5 are engaged. (refer, column “MGU Only/Coasting/Downhill” in Table 1 in FIG. 3A). The power flows from the MGU 112 via the sixth clutch C5 which further connects to the first sun gear 102A and to
10 the planet carrier assembly 108 of the first epicyclic gear train 102. The ring gear 106 may be fixed via the third clutch C2. The rotation of the first sun gear 102A may translate into the rotation of planet carrier assembly 108 as the ring gear 106 is fixed. Equation (2) is the governing equation for speed ratio in the second MGU drive mode:
��2 ∗��2
15 ��= 2∗(��2 + ��2)
… Equation (2)
[050] here, Np is angular speed of the planet carrier assembly 108; Rs2 is radius of the first sun gear 102A; and Rp2 is radius of the first set of planetary gears 20 102B.
[051] The above mode (second MGU drive mode) may also be used as level-2 regeneration braking, for the conditions when mild braking is required or during coasting downhill. 25
[052] FIG. 4C illustrates a schematic diagram of the hybrid drivetrain 100
being configured in the third MGU drive mode, in accordance with some
embodiments. The power flow in the third MGU drive mode is represented by the
dotted line in FIG. 4C. As shown in FIG. 4C, in the third MGU drive mode, the first
30 clutch C0 may be unengaged, and therefore, the first sun gear 102A may be

decoupled from the first power source 110. The second clutch C1 may be
unengaged, and therefore, the ring gear 106 may be decoupled from the first power
source 110. The third clutch C2 may be unengaged, and therefore, the rotation of
the ring gear 106 may be free. The fourth clutch C3 may be unengaged, and
5 therefore, the rotation of the first sun gear 102A and the second sun gear 104A may
not be fixed (i.e. free to rotate). The fifth clutch C4 may be engaged, and therefore, the first sun gear 102A may be coupled with the second power source 112. The sixth clutch C5 may be engaged, and therefore, the second sun gear 104A may be coupled with the second power source 112.
10
[053] The third MGU drive mode may be realized when the fifth clutch C4 and the sixth clutch C5 are engaged (refer, column “MGU Only/Coasting/Downhill (2)” in Table 1 in FIG. 3A). Further, as shown in FIG. 4A, the first sun gear 102A and the second sun gear 104A are locked via the fifth clutch C4 and the sixth clutch
15 C5. As such, the first epicyclic gear assembly 102 and the second epicyclic gear
assembly 104 are locked and the planet carrier assembly 108 may be free to rotate at same speed as the MGU 112. Therefore, the third MGU drive mode provides higher gear ratio. Further, angular speed (Np) of planet carrier assembly 108 is same as angular speed (Ns1) of the second sun gear 104A and angular speed (Ns2) of the
20 first sun gear 102A (i.e. Np = Ns1 = Ns2). The same mode may be used for level-3
regeneration braking, during coasting on highways, and during light braking.
[054] The plurality of drive modes of the vehicle may further include a set of ICE drive modes. In particular, the set of ICE drive modes may include a first
25 ICE drive mode, a second ICE drive mode, a third ICE drive mode, and a fourth
ICE drive mode. A gear ratio associated with the third ICE drive mode may be greater than a gear ratio associated with the fourth ICE drive mode. Further, a gear ratio associated with the second ICE drive mode may be greater than the gear ratio associated with the third ICE drive mode. Furthermore, a gear ratio associated with
30 the first ICE drive mode may be greater than the gear ratio associated with the

second ICE drive mode. The set of ICE drive modes are further explained in conjunction with FIGs. 5A-5D.
[055] FIG. 5A illustrates a schematic diagram of the hybrid drivetrain 100
5 being configured in the first ICE drive mode, in accordance with some
embodiments. In some embodiments, the hybrid drivetrain 100 may be configured in the first ICE drive mode when speed of the vehicle is more than 45 kilometers per hour (KPH), the state of charge (SOC) of the battery is more than 95 percent, and the throttle status of the vehicle is more than 70 percent. The power flow in the
10 first ICE drive mode is represented by the dotted line in FIG. 5A. As shown in FIG.
5A, in the first ICE drive mode, the first clutch C0 may be engaged, and therefore, the first sun gear 102A may be coupled with the first power source 110. The second clutch C1 may be unengaged, and therefore, the ring gear 106 may be decoupled from the first power source 110. The third clutch C2 may be engaged, and therefore,
15 the rotation of the ring gear 106 may be fixed. The fourth clutch C3 may be
unengaged, and therefore, the rotation of the first sun gear 102A and the second sun gear 104A may not be fixed (i.e. free to rotate). The fifth clutch C4 may be unengaged, and therefore, the first sun gear 102A may be decoupled from the second power source 112. The sixth clutch C5 may be unengaged, and therefore,
20 the second sun gear 104A may be decoupled from the second power source 112.
[056] The first ICE drive mode may be realized when the first clutch C0 and the third clutch C2 are engaged (refer, column “Engine Only” in Table 2 in FIG. 3B). The power flows from the IC engine 110 (the terms “first power source” and
25 “IC engine” may have been used interchangeably in this disclosure) via the first
clutch C0 via the first sun gear 102A to the planet carrier assembly 108. As the ring gear 106 is fixed, the power translates into the rotation of the planet carrier assembly 108. As such, the first ICE drive mode provides the highest gear ratio, and is governed by the Equation (2) above.
30

[057] FIG. 5B illustrates a schematic diagram of the hybrid drivetrain 100 being configured in the second ICE drive mode, in accordance with some embodiments. In some embodiments, the hybrid drivetrain 100 may be configured in the second ICE drive mode, when the speed of the vehicle is more than 80 KPH, 5 the SOC is less than 95 percent, and the throttle status of the vehicle is more than 70 percent. The power flow in the second ICE drive mode is represented by the dotted line in FIG. 5B. As shown in FIG. 5B, in the second ICE drive mode, the first clutch C0 may be unengaged, and therefore, the first sun gear 102A may be decoupled from the first power source 110. The second clutch C1 may be engaged,
10 and therefore, the ring gear 106 may be coupled with the first power source 110. The third clutch C2 may be unengaged, and therefore, the rotation of the ring gear 106 may be free. The fourth clutch C3 may be engaged, and therefore, the rotation of the first sun gear 102 A and the second sun gear 104A may be fixed. The fifth clutch C4 may be unengaged, and therefore, the first sun gear 102A may be
15 decoupled from the second power source 112. The sixth clutch C5 may be engaged, and therefore, the second sun gear 104A may be coupled with the second power source 112.
[058] The second ICE drive mode may be realized when the second clutch, 20 the fourth clutch C3, and the sixth clutch C5 are engaged (refer, column “Engine Only 2” in Table 2 in FIG. 3B). The power flows from the IC engine 110 to the ring gear 106 via the first clutch C1. The first sun gear 102A is fixed via the sixth clutch C5. As such, the power is transferred from the ring gear 106 to the planet carrier assembly 108. The gear ratio of the second ICE drive mode is governed by Equation 25 (3):
= 2∗��1∗(��1 + ��1)
�� 2∗��1 + ��1
… Equation (3)

[059] here, Nr is angular speed of the ring gear 106; Np1 is angular speed of the second set of planetary gears 104B; Rs1 is radius of second sun gear 104A; Rp1 is radius of the second set of planetary gears 104B.
5 [060] FIG. 5C illustrates a schematic diagram of the hybrid drivetrain 100
being configured in the third ICE drive mode, in accordance with some embodiments. In some embodiments, the hybrid drivetrain 100 may be configured in the third ICE drive mode when the speed of the vehicle is more than 110 KPH, the SOC is less than 95 percent, and the throttle status of the vehicle is more than
10 70 percent. Alternatively, the hybrid drivetrain 100 may be configured in the third
ICE drive mode when the speed of the vehicle is more than 80 KPH, the SOC is less than 95 percent, and the throttle status of the vehicle is less than 70 percent. The power flow in the third ICE drive mode is represented by the dotted line in FIG. 5C. As shown in FIG. 5C, in the third ICE drive mode, the first clutch C0 may
15 be unengaged, and therefore, the first sun gear 102A may be decoupled from the
first power source 110. The second clutch C1 may be engaged, and therefore, the ring gear 106 may be coupled with the first power source 110. The third clutch C2 may be unengaged, and therefore, the rotation of the ring gear 106 may be free. The fourth clutch C3 may be engaged, and therefore, the rotation of the first sun gear
20 102A and the second sun gear 104A may be fixed. The fifth clutch C4 may be
engaged, and therefore, the first sun gear 102A may be coupled with the second power source 112. The sixth clutch C5 may be unengaged, and therefore, the second sun gear 104A may be decoupled from the second power source 112.
25 [061] As such, the third ICE drive mode may be realized when the second
clutch C1, the fourth clutch C3, and the fifth clutch C4 are engaged (refer, column “Engine Only 3” in Table 2 in FIG. 3B). The power flows from the IC engine 110 to the ring gear 106 via the second clutch C1. The second sun gear 104A is fixed via the fifth clutch C4, and therefore, the power gets transferred from the ring gear
30 106 to the planet carrier assembly 108. The gear ratio for the third ICE drive mode
is governed by the Equation (4):

= 2∗��2∗(��2 + ��2)
�� 2∗��2 + ��2
…Equation (4)
[062] here, Nr is angular speed of the ring gear 106; Np2 is angular speed 5 of the first set of planetary gears 102B; Rs2 is radius of the first sun gear 102A; Rp2 is radius of the first set of planetary gears 102B.
[063] FIG. 5D illustrates a schematic diagram of the hybrid drivetrain 100 being configured in the fourth ICE drive mode, in accordance with some
10 embodiments. In some embodiments, the hybrid drivetrain 100 may be configured in the fourth ICE drive mode when the speed of the vehicle is more than 145 KPH and the SOC is less than 95 percent. Alternatively, the hybrid drivetrain 100 may be configured in the fourth ICE drive mode when the speed of the vehicle is more than 110 KPH, the SOC is less than 95 percent, and the throttle status of the vehicle
15 is less than 70 percent. The power flow in the fourth ICE drive mode is represented by the dotted line in FIG. 5D. As shown in FIG. 5D, in the third ICE drive mode, the first clutch C0 may be engaged, and therefore, the first sun gear 102A may be coupled with the first power source 110. The second clutch C1 may be engaged, and therefore, the ring gear 106 may be coupled with the first power source 110.
20 The third clutch C2 may be unengaged, and therefore, the rotation of the ring gear 106 may be free. The fourth clutch C3 may be unengaged, and therefore, the rotation of the first sun gear 102A and the second sun gear 104A may not be fixed (i.e. free to rotate). The fifth clutch C4 maybe unengaged, and therefore, the first sun gear 102A may be decoupled from the second power source 112. The sixth
25 clutch C5 may be unengaged, and therefore, the second sun gear 104A may be decoupled from the second power source 112.
[064] The fourth ICE drive mode may be realized when the first clutch C0
and the second clutch C1 are engaged (refer, column “Engine Only 4” in Table 2 in
30 FIG. 3B). Power flows from the IC engine 110 to the ring gear 106 and via the first

clutch C0 and the second clutch C1, which are fixed together to the housing 202.
Thus, the complete transmission acts as a single unit and the planet carrier assembly
108 rotates with the speed of the IC engine 110. The gear ratio is 1:1 between the
IC engine 110 and the planet carrier assembly 108. As such, angular speed (Np) of
5 planet carrier assembly 108 is same as angular speed (Ns1) of the second sun gear
104A, the angular speed (Ns2) of the first sun gear 102A, and the angular speed (Nr) of the ring gear 106 (i.e. Np = Ns1 = Ns2 = Nr).
[065] The plurality of drive modes of the vehicle may further include a set
10 of hybrid drive modes. In particular, the set of hybrid drive modes may include a
first hybrid drive mode, a second hybrid drive mode, a third hybrid drive mode, and a fourth hybrid drive mode. In some embodiments, a gear ratio associated with the third hybrid drive mode may be greater than a gear ratio associated with the fourth hybrid drive mode. A gear ratio associated with the second hybrid drive mode may
15 be greater than the gear ratio associated with the third hybrid drive mode. A gear
ratio associated with the first hybrid drive mode may be greater than the gear ratio associated with the second hybrid drive mode. The set of hybrid drive modes are further explained in conjunction with FIGs. 6A-6D.
[066] FIG. 6A illustrates a schematic diagram of the hybrid drivetrain 100
20 being configured in the first hybrid drive mode, in accordance with some
embodiments. The power flow in the first hybrid drive mode is represented by the dotted line in FIG. 6A. As shown in FIG. 6A, in the first hybrid drive mode, the first clutch C0 may be engaged, and therefore, the first sun gear 102A may be coupled with the first power source 110. The second clutch C1 may be unengaged,
25 and therefore, the ring gear 106 may be decoupled from the first power source 110.
The third clutch C2 may be engaged, and therefore, the rotation of the ring gear 106 may be fixed. The fourth clutch C3 may be unengaged, and therefore, the rotation of the first sun gear 102A and the second sun gear 104A may not be fixed (i.e. free to rotate). The fifth clutch C4 may be unengaged, and therefore, the first sun gear
30 102A may be decoupled from the second power source 112. The sixth clutch C5

may be engaged, and therefore, the second sun gear 104A may be coupled with the second power source 112.
[067] In the first hybrid drive mode (refer, column “Hybrid Mode (1)” in
5 Table 3 I FIG. 3B), the first clutch C0, the third clutch C2, and the sixth clutch C5
are engaged. Both the IC engine 110 and the MGU 112 may provide power to the
first sun gear 102A via the first clutch C0 and the sixth clutch C5, respectively. As
the ring gear 106 is fixed, the power from the first sun gear 102A may translate into
rotation of the planet carrier assembly 108. The gear ratios of the first hybrid drive
10 mode are governed by Equation (2) above.
[068] FIG. 6B illustrates a schematic diagram of the hybrid drivetrain 100 being configured in the second hybrid drive mode, in accordance with some embodiments. In some embodiments, the hybrid drivetrain 100 may be configured
15 in the second hybrid drive mode when the speed of the vehicle is more than 45
KPH, the SOC is more than 95 percent, and the throttle status of the vehicle is less than 70 percent. The power flow in the second hybrid drive mode is represented by the dotted line in FIG. 6B. As shown in FIG. 6B, in the first clutch C0 may be unengaged, and therefore, the first sun gear 102A may be decoupled from the first
20 power source 110. The second clutch C1 may be engaged, and therefore, the ring
gear 106 may be coupled with the first power source 110. The third clutch C2 may be unengaged, and therefore, the rotation of the ring gear 106 may be free. The fourth clutch C3 may be unengaged, and therefore, the rotation of the first sun gear 102A and the second sun gear 104A may not be fixed (i.e. free to rotate). The fifth
25 clutch C4 may be engaged, and therefore, the first sun gear 102A may be coupled
with the second power source 112. The sixth clutch C5 may be engaged, and therefore, the second sun gear 104A may be coupled with the second power source 112.
30 [069] The second hybrid drive mode is realized when the second clutch C1,
the fifth clutch C4, and the sixth clutch C5 are engaged (refer, column “Hybrid

Mode (2)” in Table 3 in FIG. 3C). The IC engine 110 and the MGU 112 may
provide combined power to the planet carrier assembly 108. As the fifth clutch C4
and the sixth clutch C5 are engaged, the transmission acts as a single unit and rotates
with the speed of the IC engine 110 and the MGU 112. As such, angular speed (Np)
5 of planet carrier assembly 108 is same as angular speed (Ns1) of the second sun
gear 104A, the angular speed (Ns2) of the first sun gear 102A, and the angular speed (Nr) of the ring gear 106 (i.e. Np = Ns1 = Ns2 = Nr) which is same as is the speed of the IC engine 110 and the MGU 112. Therefore, the speed ratio between the IC engine 110 (or the MGU 112) and the planet carrier 108 is 1:1.
10
[070] FIG. 6C illustrates a schematic diagram of the hybrid drivetrain 100 being configured in the third hybrid drive mode, in accordance with some embodiments. In some embodiments, the hybrid drivetrain 100 may be configured in the third hybrid drive mode when the speed of the vehicle is more than 145 KPH
15 and the SOC is more than 95 percent. Alternatively, the hybrid drivetrain 100 may
be configured in the third hybrid drive mode when the speed of the vehicle is more than 110 KPH, the SOC is more than 95 percent, and the throttle status of the vehicle is less than 70 percent. The power flow in the third hybrid drive mode is represented by the dotted line in FIG. 6C. As shown in FIG. 6C, the first clutch (C0) may be
20 unengaged, and therefore, the first sun gear 102A may be decoupled from the first
power source 110. The second clutch C1 may be engaged, and therefore, the ring gear 106 may be coupled with the first power source 110. The third clutch C2 may be unengaged, and therefore, the rotation of the ring gear 106 may be free. The fourth clutch C3 may be unengaged, and therefore, the rotation of the first sun gear
25 102A and the second sun gear 104A may not be fixed (i.e. free to rotate). The fifth
clutch C4 may be engaged, and therefore, the first sun gear 102A may be coupled with the second power source 112. The sixth clutch C5 may be unengaged, and therefore, the second sun gear 104A may be decoupled from the second power source 112.
30
-25-

[071] The third hybrid drive mode is realized when the second clutch C1
and the sixth clutch C5 are engaged (refer, column “Hybrid Mode (3)” in Table 3
in FIG. 3C). The IC engine 110 provides power to the ring gear 106 via the first
clutch C1; and the MGU 112 provides power to the first sun gear 102 A via the sixth
5 clutch C5. The power from the IC engine 110 and the MGU 112 is combined, and
the speed ratio between the IC engine 110 and the planet carrier assembly 108 is
varied by varying the speed of MGU 112. The third hybrid drive mode may also be
utilized as an overdrive ratio for the IC engine 110. The speed ratio is governed by
Equation (5):
= 2 ∗ �� ∗ (��2 + ��2) - �� ∗ ��2
10 �� 2∗��2 + ��2
… Equation (5)
[072] here, Nr is angular speed of the ring gear 106; Np is angular speed of the planet carrier assembly 108; Rs2 is radius of the first sun gear 102A; Rp2 is
15 radius of the first set of planetary gears 102B; and Ns is the angular speed of sun gear.
[073] In the third hybrid drive mode, the IC engine 110 rotates at maximum RPM. The MGU 112 may rotate in the opposite direction to the IC engine 110 to increase the speed ratio.
20
[074] FIG. 6D illustrates a schematic diagram of the hybrid drivetrain 100 being configured in the fourth hybrid drive mode, in accordance with some embodiments. The power flow in the fourth hybrid drive mode is represented by the dotted line in FIG. 6D. As shown in FIG. 6D, the first clutch C0 may be
25 unengaged, and therefore, the first sun gear 102A may be decoupled from the first power source 110. The second clutch C1 may be engaged, and therefore, the ring gear 106 may be coupled with the first power source 110. The third clutch C2 may be unengaged, and therefore, the rotation of the ring gear 106 may be free. The fourth clutch C3 may be unengaged, and therefore, the rotation of the first sun gear
30 102A and the second sun gear 104A may not be fixed (i.e. free to rotate). The fifth

clutch C4 may be unengaged, and therefore, the first sun gear 102A may be decoupled from the second power source 112. The sixth clutch C5 may be engaged, and therefore, the second sun gear 104A may be coupled with the second power source 112. 5
[075] The fourth hybrid drive mode is similar to the third hybrid drive mode, where the second sun gear 104A connects to the MGU 112 via the fifth clutch C4 instead of the sixth clutch C5.
10 [076] The plurality of drive modes of the vehicle may further include a start-
and-idle drive mode. FIG. 7 illustrates a schematic diagram of the hybrid drivetrain 100 being configured in the start-and-idle drive mode, in accordance with some embodiments. The power flow in the start-and-idle drive mode is represented by the dotted line in FIG. 7. In the start-and-idle drive mode, the first clutch C0 may
15 be unengaged, and therefore, the first sun gear 102A may be decoupled from the
first power source 110. The second clutch C1 may be engaged, and therefore, the ring gear 106 may be coupled with the first power source 110. The third clutch C2 may be unengaged, and therefore, the rotation of the ring gear 106 may be free. The fourth clutch C3 may be unengaged, and therefore, the rotation of the first sun gear
20 102A and the second sun gear 104A may not be fixed (i.e. free to rotate). The fifth
clutch C4 may be engaged, and therefore, the first sun gear 102A may be coupled with the second power source 112. The sixth clutch C5 may be unengaged, and therefore, the second sun gear 104A may be decoupled from the second power source 112. The start-and-idle drive mode may applied to start the IC engine 110.
25
[077] Apart from the above drive modes, the vehicle may run in an idle mode. FIG. 8 illustrates a schematic diagram of the hybrid drivetrain 100 being configured in the idle mode, in accordance with some embodiments. In the idle mode, each of the first clutch C0, the second clutch C1, the third clutch C2, the
30 fourth clutch C3, the fifth clutch C4, and the sixth clutch C5 may be unengaged. In
particular, the first clutch C0 may be unengaged, and therefore, the first sun gear

102A may be decoupled from the first power source 110. The second clutch C1
may be unengaged, and therefore, the ring gear 106 may be decoupled from the first
power source 110. The third clutch C2 may be unengaged, and therefore, the
rotation of the ring gear 106 may be free. The fourth clutch C3 may be unengaged,
5 and therefore, the rotation of the first sun gear 102A and the second sun gear 104A
may not be fixed (i.e. free to rotate). The fifth clutch C4 may be unengaged, and
therefore, the first sun gear 102A may be decoupled from the second power source
112. The sixth clutch C5 may be unengaged, and therefore, the second sun gear
104A may be decoupled from the second power source 112. In the idle mode, only
10 the IC engine 110 may provide power that may not be transmitted to the wheels of
the vehicle.
[078] Referring now to FIG. 9, a schematic diagram of a system 900 for controlling drive modes in the hybrid drivetrain 100 of a vehicle is illustrated, in
15 accordance with some embodiments. As explained above in conjunction with FIG.
1, the hybrid drivetrain 100 may include the first epicyclic gear assembly 102 that may include the first sun gear 102A and the first set of planetary gears 102B. Each of the first set of planetary gears 102B may be engaged with the first sun gear 102A. The hybrid drivetrain 100 may further include the second epicyclic gear assembly
20 104 that may further include the second sun gear 104A and the second set of
planetary gears 104B. Each of the second set of planetary gears 104B may be engaged with the second sun gear 104A. The hybrid drivetrain 100 may further include the ring gear 106 engaged with each of the first set of planetary gears 102B and the second set of planetary gears 104B, and the planet carrier assembly 108
25 coupled to the set of wheels of a vehicle to drive the set of wheels. The first set of
planetary gears 102B and the second set of planetary gears 104B may be rotatably coupled to the planet carrier assembly 108.
[079] The hybrid drivetrain 100 may further include the plurality of clutches
30 C0-C5 configured to selectively couple the first sun gear 102A and the ring gear
106 with the first power source 110, and selectively couple the first sun gear 102A

and the second sun gear 104A with the second power source 112, to obtain the plurality of drive modes of the vehicle. As such, in each of the plurality of drive modes, the vehicle may be driven by the first power source 110, or the second power source 112, or a combination thereof. 5
[080] In order to obtain the plurality of drive modes, the system 900 may include an electronic control unit (ECU) 902 and a plurality of actuators 904. In particular, the plurality of actuators 904 may include an actuator 904-1, an actuator 904-2, an actuator 904-3, … and so on (as such, the actuators may be collectively
10 referred to as plurality of actuator 904). For example, each of the plurality of
actuator 904 may be configured to trigger one of the plurality of clutches C0-C5. B way of an example, each of the plurality of actuator 904 may include a servo motor operated with electrical power, and configured to generate a linear movement to move the respective clutch between an engaged position and an unengaged position.
15
[081] The ECU 902, for example, may include an existing ECU of the vehicle, or a dedicated ECU provided specifically for controlling drive modes in the hybrid drivetrain 100 of the vehicle. The ECU 902 may be a computing device having data processing capability. Also, examples of the ECU 902 may include, but
20 are not limited to a desktop, a laptop, a notebook, a netbook, a tablet, a smartphone,
a mobile phone, an application server, a web server, or the like. In some embodiments, the ECU 902 may include a processor 902A and a memory 902B. The memory 902B may be communicatively coupled to the processor 902A. The memory 902B stores a plurality of instructions, which upon execution by the
25 processor 902A, cause the processor 902A to perform the various one or more
functionalities.
[082] The one or more functionalities may include receiving one or more
parameters 906 associated with the vehicle corresponding to a current running state
30 of the vehicle. For example, the one or more parameters 906 may include a speed
of the vehicle, a throttle status of the vehicle, a braking status of the vehicle, a state

of charge (SoC) of a battery of the vehicle, and a gradient of elevation of a terrain
on which the vehicle is traveling. The one or more functionalities may further
include selecting a drive mode from a plurality of drive modes, based on the one or
more parameters. As mentioned above, the plurality of drive modes may include a
5 set of MGU drive modes, a set of ICE drive modes, a set of hybrid drive modes, a
start-and-idle mode, and an idle mode.
[083] The one or more functionalities may further include triggering at least one of the plurality of actuators 904 to configure respective clutches of the plurality
10 of clutches C0-C5 in an engaged configuration, to selectively couple the first sun
gear 102A and the ring gear 106 with the first power source 110 (i.e. the IC engine), and selectively couple the first sun gear 102A and the second sun gear 104A with the second power source 112 (i.e. the MGU), to thereby achieve the plurality of drive modes.
15
[084] Referring now to FIG. 10, a flowchart of a method 1000 of controlling drive modes in the hybrid drivetrain 100 is illustrated, in accordance with some embodiments. The method 1000 may be performed, for example, by the ECU 902 or the processor 902A of the ECU 902.
20
[085] At step 1002, one or more parameters associated with the vehicle corresponding to a current running state of the vehicle may be received. For example, the one or more parameters may include a speed of the vehicle, a throttle status of the vehicle, a braking status of the vehicle, a state of charge (SoC) of a
25 battery of the vehicle, and a gradient of elevation of a terrain on which the vehicle
is traveling.
[086] At step 1004, a drive mode from a plurality of drive modes may be
selected, based on the one or more parameters. As mentioned above, the plurality
30 of drive modes may include a set of MGU drive modes, a set of ICE drive modes,
a set of hybrid drive modes, a start-and-idle mode, and an idle mode.

[087] At step 1006, at least one of the plurality of actuators 904 may be
triggered to configure respective clutches of the plurality of clutches C0-C5 in an
engaged configuration, to selectively couple the first sun gear 102A and the ring
5 gear 106 with the first power source 110 (i.e. the IC engine), and selectively couple
the first sun gear 102A and the second sun gear 104A with the second power source 112 (i.e. the MGU), to thereby achieve the plurality of drive modes. As further mentioned above, the first sun gear 102A may be coupled with the first set of planetary gears 102B of the first epicyclic gear assembly 102. The second sun gear
10 104A may be coupled with the second set of planetary gears 104B of the second
epicyclic gear assembly 104. The planet carrier assembly 108 may be coupled to the set of wheels of the vehicle. The first set of planetary gears 102B and the second set of planetary gears 104B may be rotatably coupled to the planet carrier assembly 108. The ring gear 106 may be engaged with each of the first set of planetary gears
15 102B and the second set of planetary gears 104B.
[088] Referring now to FIG. 11, a flowchart of a method 1100 of controlling
drive modes in the hybrid drivetrain 100 is illustrated, in accordance with some
embodiments. The method 1100 may be performed, for example, by the ECU 902
20 or the processor 902A of the ECU 902.
[089] At step 1102, one or more parameters associated with the vehicle
corresponding to a current running state of the vehicle may be received. For
example, the one or more parameters may include a speed of the vehicle, a throttle
25 status of the vehicle, a braking status of the vehicle, a state of charge (SoC) of a
battery of the vehicle, and a gradient of elevation of a terrain on which the vehicle is traveling.
[090] At step 1104, a check may be performed to determine whether the
30 braking applied is less than 80%. If at step 1104, it is determined that the braking
applied is NOT less than 80%, the method 1100 may proceed to step 1106 (“No”

path) at which a check may be performed to check whether the SoC of the vehicle
is greater than 95%. If at step 1106, it is determined that the SoC of the vehicle is
NOT greater than 95%, the method 1100 may proceed to step 1108 (“No” path), at
which full braking with level-3 regeneration braking may be applied. If at step 1106,
5 it is determined that the SoC of the vehicle is greater than 95%, the method 1100
may proceed to step 1110 (“Yes” path), at which full braking with no regeneration braking may be applied.
[091] If at step 1104, it is determined that the braking applied is less than
10 80%, the method 1100 may proceed to step 1112 (“Yes” path) at which a check
may be performed to check whether the braking applied is less than 50%. If at step
1112, it is determined that the braking applied is NOT less than 50%, the method
1100 may proceed to step 1114 (“No” path), at which a check may be performed to
check whether the gradient of slope of terrain on which the vehicle is traveling is
15 greater than 0.2. If at step 1114, it is determined that the gradient of slope is NOT
greater than 0.2, the method may proceed to step 1116 (“No” path), at which a check
may be performed to determine whether the SoC of the vehicle is greater than 95%.
If at step 1116, it is determined that the SoC of the vehicle is NOT greater than
95%, the method 1100 may proceed to step 1118 (“No” path), at which mild braking
20 with level-2 regeneration braking may be applied. If at step 1116, it is determined
that the SoC of the vehicle is greater than 95%, the method 1100 may proceed to
step 1120 (“Yes” path), at which mild braking with no regeneration braking may
be applied.
25 [092] If at step 1114, it is determined that the gradient of slope is greater
than 0.2, the method may proceed to step 1122 (“No” path), at which a check may be performed to determine whether the SoC of the vehicle is greater than 95%. If at step 1122, it is determined that the SoC of the vehicle is NOT greater than 95%, the method 1100 may proceed to step 1124 (“No” path), at which full braking with
30 level-3 regeneration braking may be applied. If at step 1122, it is determined that

the SoC of the vehicle is greater than 95%, the method 1100 may proceed to step 1126 (“Yes” path), at which low braking with no regeneration may be applied.
[093] If at step 1112, it is determined that the braking applied is less than
5 50%, the method 1100 may proceed to step 1128 (“Yes” path), at which a check
may be performed to check whether the braking applied is less than 20%. If at step 1128, it is determined that the braking applied is NOT less than 20%, the method 1100 may proceed to step 1130, at which a check may be performed to determine whether the gradient of slope of terrain on which the vehicle is traveling is greater
10 than 0.2. If at step 1130, it is determined that the gradient of slope is NOT greater
than 0.2, the method may proceed to step 1132 (“No” path), at which a check may be performed to determine whether the SoC of the vehicle is greater than 95%. If at step 1132, it is determined that the SoC of the vehicle is NOT greater than 95%, the method 1100 may proceed to step 1134 (“No” path), at which low braking with
15 level-1 regeneration braking may be applied. If at step 1132, it is determined that
the SoC of the vehicle is greater than 95%, the method 1100 may proceed to step 1136 (“Yes” path), at which low braking with no regeneration may be applied.
[094] If at step 1130, it is determined that the gradient of slope is greater
20 than 0.2, the method may proceed to step 1138 (“No” path), at which a check may
be performed to determine whether the SoC of the vehicle is greater than 95%. If at
step 1138, it is determined that the SoC of the vehicle is NOT greater than 95%, the
method 1100 may proceed to step 1140 (“No” path), at which mild braking with
level-2 regeneration braking may be applied. If at step 1138, it is determined that
25 the SoC of the vehicle is greater than 95%, the method 1100 may proceed to step
1142 (“Yes” path), at which mild braking with no regeneration may be applied.
[095] If at step 1128, it is determined that the braking applied is less than
20%, the method 1100 may proceed to step 1144, at which a check may be
30 performed to determine whether the SoC of the vehicle is greater than 95%. If at
step 1144, it is determined that the SoC of the vehicle is NOT greater than 95%, the

method 1100 may proceed to step 1146 (“No” path), at which low braking with level-1 regeneration braking may be applied. If at step 1144, it is determined that the SoC of the vehicle is greater than 95%, the method 1100 may proceed to step 1148 (“Yes” path), at which low braking with no regeneration may be applied. 5
[096] Referring now to FIG. 12, a flowchart of a method 1200 of controlling drive modes in the hybrid drivetrain 100 is illustrated, in accordance with some embodiments. The method 1200 may be performed, for example, by the ECU 902 or the processor 902A of the ECU 902.
10
[097] At step 1202, one or more parameters associated with the vehicle corresponding to a current running state of the vehicle may be received. For example, the one or more parameters may include a speed of the vehicle, a throttle status of the vehicle, a braking status of the vehicle, a state of charge (SoC) of a
15 battery of the vehicle, and a gradient of elevation of a terrain on which the vehicle
is traveling.
[098] At step 1204, a check may be performed to determine whether the speed of the vehicle is less than 145 kilometers per hour (KPH). If at step 1204, it
20 is determined that the speed of the vehicle is NOT less than 145 KPH, the method
1200 may proceed to step 1206 (“No” path) at which a check may be performed to check whether the SoC of the vehicle is greater than 95%. If at step 1206, it is determined that the SoC of the vehicle is NOT greater than 95%, the method 1200 may proceed to step 1208 (“No” path), at which the fourth ICE drive mode may
25 applied. If at step 1206, it is determined that the SoC of the vehicle is greater than
95%, the method 1200 may proceed to step 1210 (“Yes” path), at which the third hybrid drive mode may applied.
[099] If at step 1204, it is determined that the speed of the vehicle is less
30 than 145 KPH, the method 1200 may proceed to step 1212 (“Yes” path) at which a
check may be performed to check whether the speed of the vehicle is less than 110

KPH. If at step 1212, it is determined that the speed of the vehicle is NOT less than 110 KPH, the method 1200 may proceed to step 1214 (“No” path), at which a check may be performed to check whether the SoC of the vehicle is greater than 95%.
5 [0100] If at step 1214, it is determined that the SoC of the vehicle is NOT
greater than 95%, the method 1200 may proceed to step 1216 (“No” path), at which
a check may be performed to check whether the throttle of the vehicle is greater
than 70%. If at step 1216, it is determined that the throttle of the vehicle is NOT
greater than 70%, the method 1200 may proceed to step 1218 (“No” path), at which
10 fourth ICE drive mode may be applied. If at step 1216, it is determined that the
throttle of the vehicle is greater than 70%, the method 1200 may proceed to step 1220 (“Yes” path), at which the third ICE drive mode may be applied.
[0101] If at step 1214, it is determined that the SoC of the vehicle is greater
15 than 95%, the method 1200 may proceed to step 1222 (“Yes” path), at which a
check may be performed to check whether the throttle of the vehicle is greater than
70%. If at step 1222, it is determined that the throttle of the vehicle is NOT greater
than 70%, the method 1200 may proceed to step 1224 (“No” path), at which the
third hybrid drive mode may be applied. If at step 1222, it is determined that the
20 throttle of the vehicle is greater than 70%, the method 1200 may proceed to step
1226 (“Yes” path), at which the second hybrid drive mode may be applied.
[0102] If at step 1212, it is determined that the speed of the vehicle is less
than 110 KPH, the method 1200 may proceed to step 1228 (“Yes” path), at which
25 a check may be performed to check whether the speed of the vehicle is less than 80
KPH.
[0103] If at step 1228, it is determined that the speed of the vehicle is NOT
less than 80 KPH, the method 1200 may proceed to step 1230 (“No” path), at which
30 a check may be performed to determine whether the SoC of the vehicle is greater
than 95%. If at step 1230, it is determined that SoC of the vehicle is NOT greater

than 95%, the method 1200 may proceed to step 1232 (“No” path) at which a check
may be performed to determine whether the throttle of the vehicle is greater than
70%. If at step 1232, it is determined that the throttle of the vehicle is NOT greater
than 70%, the method 1200 may proceed to step 1234 (“No” path), at which the
5 third ICE drive mode may be applied. If at step 1232, it is determined that the
throttle of the vehicle is greater than 70%, the method 1200 may proceed to step 1236 (“Yes” path), at which the second ICE drive mode may be applied. If at step 1230, it is determined that the SoC of the vehicle is greater than 95%, the method 1200 may proceed to step 1238 (“Yes” path), at which a check may be performed
10 to check whether the throttle of the vehicle is greater than 70%. If at step 1238, it is
determined that the throttle of the vehicle is NOT greater than 70%, the method 1200 may proceed to step 1240 (“No” path), at which the third hybrid drive mode may be applied. If at step 1238, it is determined that the throttle of the vehicle is greater than 70%, the method 1200 may proceed to step 1242 (“Yes” path), at which
15 the second hybrid drive mode may be applied.
[0104] If at step 1228, it is determined that the speed of the vehicle is less than 80 KPH, the method 1200 may proceed to step 1244 (“Yes” path), at which a check may be performed to determine whether the speed of the vehicle is less than
20 45 KPH. If at step 1244, it is determined that the speed of the vehicle is NOT less
than 45 KPH, the method 1200 may proceed to step 1246 (“No” path), at which a check may be performed to determine whether the SoC of the vehicle is greater than 95%. If at step 1246, it is determined that SoC of the vehicle is NOT greater than 95%, the method 1200 may proceed to step 1248 (“No” path) at which a check may
25 be performed to determine whether the throttle of the vehicle is greater than 70%.
If at step 1248, it is determined that the throttle of the vehicle is NOT greater than 70%, the method 1200 may proceed to step 1250 (“No” path), at which the second ICE drive mode may be applied. If at step 1248, it is determined that the throttle of the vehicle is greater than 70%, the method 1200 may proceed to step 1252 (“Yes”
30 path), at which the first ICE drive mode may be applied. If at step 1246, it is
determined that the SoC of the vehicle is greater than 95%, the method 1200 may

proceed to step 1254 (“Yes” path), at which a check may be performed to check whether the throttle of the vehicle is greater than 70%. If at step 1254, it is determined that the throttle of the vehicle is NOT greater than 70%, the method 1200 may proceed to step 1256 (“No” path), at which the second hybrid drive mode may be applied. If at step 1254, it is determined that the throttle of the vehicle is greater than 70%, the method 1200 may proceed to step 1258 (“Yes” path), at which the low braking with no regeneration may be applied.
[0105] The above-described solutions (the hybrid drivetrain, the system, and the methods) provide various advantages. For example, by implementing the various drive modes, the overall efficiency of the vehicle is improved by 30-40%. Further, the set of MGU drive modes allow the IC engine to be turned off and achieve about one-third of the maximum power. The plug-in solution provided by the present disclosure improves the overall operating cost (i.e. cost per kilometer). Further, the solutions allow for running the IC engine in ideal RPM range for best performance and fuel economy. Furthermore, the solutions allow using Atkinson cycle engine for better thermal efficiency. The solutions further allow for engine downsizing (for example, 2:1 power ratio for IC engine: MGU) that results in better economy (as such, even lower segment engines can be used). The solutions provide for improved performance (better torque delivery), by optimally delivering power from the IC engine and the MGU to the wheels of the vehicle. In particular, the initial torque from the MGU significantly elevates the torque as compared to the conventional manual or automatic transmissions. The solutions provide for reduced emissions, as the IC engine can run in the most efficient range of power, thereby providing a better alternative to diesel engines with comparable performance and cost. The solutions further provide for improved driving range, due to additional power from the regeneration braking. Also, idle waiting time for charging (as in EVs) is minimized. As a result, the overall ownership cost of the vehicle is lowered, as compared to electric and IC engine counterparts. Due to a smaller battery pack for city range, the cost of vehicle is lowered, as compared to the EV counterparts. Moreover, the above solutions do away with the requirement of dedicated multi-

speed transmission, thereby saving cost. Further, with lesser stress on the conventional braking system due to regenerative braking, the brake pad life is improved.
[0106] It is intended that the disclosure and examples be considered as exemplary only, with a true scope and spirit of disclosed embodiments being indicated by the following claims.

We Claims:
1. A hybrid drivetrain (100) comprising:
a first epicyclic gear assembly (102) comprising:
5 a first sun gear (102A); and
a first set of planetary gears (102B), each of the first set of
planetary gears (102B) being engaged with the first sun gear (102A);
a second epicyclic gear assembly (104) comprising;
a second sun gear (104A); and
10 a second set of planetary gears (104B), each of the second set of
planetary gears (104B) being engaged with the second sun gear (104A); a ring gear (106) engaged with each of the first set of planetary gears (102B) and the second set of planetary gears (104B);
a planet carrier assembly (108) coupled to a set of wheels of a vehicle to
15 drive the set of wheels, wherein the first set of planetary gears (102B) and the
second set of planetary gears (104B) are rotatably coupled to the planet carrier assembly (108); and
a plurality of clutches configured to selectively couple the first sun gear
(102A) and the ring gear (106) with a first power source (110), and selectively
20 couple the first sun gear (102A) and the second sun gear (104A) with a second
power source (112), to obtain a plurality of drive modes of the vehicle, wherein in each of the plurality of drive modes, the vehicle is driven by the first power source (110), or the second power source (112), or a combination thereof.
25 2. The hybrid drivetrain (100) as claimed in claim 1, wherein the plurality of
clutches comprises:
a first clutch (C0) configured to selectively couple the first sun gear (102A) with the first power source (110);
a second clutch (C1) configured to selectively couple the ring gear (106)
30 with the first power source (110);

a third clutch (C2) configured to selectively fix rotation of the ring gear (106);
a fourth clutch (C3) configured to selectively fix rotation of the first sun
gear (102A) and the second sun gear (104A);
5 a fifth clutch (C4) configured to selectively couple the first sun gear
(102A) with the second power source (112); and
a sixth clutch (C5) configured to selectively couple the second sun gear (104A) with the second power source (112).
10 3. The hybrid drivetrain (100) as claimed in claim 1 comprising:
a first shaft (114A) coupled with the first sun gear (102A);
a second shaft (114B) coupled with the second sun gear (104A);
a third shaft (114C) coupled with the ring gear (106),
wherein the first shaft (114A), the second shaft (114B), and the
15 third shaft (114C) are concentric; and
wherein the plurality of clutches is configured to selectively couple the first sun gear (102A) with the first power source (110) and the second power source (112), via the first shaft (114A),
wherein the plurality of clutches is configured to selectively couple
20 the second sun gear (104A) with the second power source (112), via the
second shaft (114B), and
wherein the plurality of clutches is configured to selectively couple the ring gear (106) with the first power source (110), via the third shaft (114C). 25
4. The hybrid drivetrain (100) as claimed in claim 1,
wherein the first power source (110) is an Internal Combustion Engine (ICE); and
wherein the second power source (112) is a Motor Generator Unit (MGU). 30

5. A system for controlling drive modes in a hybrid drivetrain (100) of a vehicle, the system comprising:
a first epicyclic gear assembly (102) comprising:
a first sun gear (102A); and
5 a first set of planetary gears (102B), each of the first set of
planetary gears (102B) engaged with the first sun gear (102A); a second epicyclic gear assembly (104) comprising: a second sun gear (104A); and
a second set of planetary gears (104B), each of the second set of
10 planetary gears (104B) engaged with the second sun gear (104A);
a ring gear (106) engaged with each of the first set of planetary gears (102B) and the second set of planetary gears (104B);
a planet carrier assembly (108) coupled to a set of wheels of the vehicle to
drive the set of wheels, wherein the first set of planetary gears (102B) and the
15 second set of planetary gears (104B) are rotatably coupled to the planet carrier
assembly (108);
a plurality of clutches;
a plurality of actuators, each of the plurality of actuators engaging with
one of the plurality of clutches to change a configuration of the respective clutch
20 between an engaged configuration and an unengaged configuration;
a processor; and
a memory communicatively coupled with the processor, the memory
storing processor-executable instructions, wherein the processor-executable
instructions, on execution by the processor, cause the processor to:
25 receive one or more parameters associated with the vehicle
corresponding to a current running state of the vehicle;
select a drive mode from a plurality of drive modes, based on the one or more parameters; and
trigger at least one of the plurality of actuators to configure the
30 respective clutches of the plurality of clutches in the engaged
configuration, to selectively couple the first sun gear (102A) and the ring

gear (106) with a first power source (110), or selectively couple the first
sun gear (102A) and the second sun gear (104A) with a second power
source (112), to thereby obtain a drive mode of the plurality of drive
modes of the vehicle, wherein in each of the plurality of drive modes, the
5 vehicle is driven by the first power source (110), or the second power
source (112), or a combination thereof.
6. The system as claimed in claim 5, wherein the plurality of clutches comprises:
a first clutch (C0) configured to selectively couple the first sun gear
10 (102A) with the first power source (110);
a second clutch (C1) configured to selectively couple the ring gear (106) with the first power source (110);
a third clutch (C2) configured to selectively fix rotation of the ring gear
(106);
15 a fourth clutch (C3) configured to selectively fix rotation of the first sun
gear (102A) and the second sun gear (104A);
a fifth clutch (C4) configured to selectively couple the first sun gear (102A) with the second power source (112); and
a sixth clutch (C5) configured to selectively couple the second sun gear
20 (104A) with the second power source (112).
7. The system as claimed in claim 6, wherein the one or more parameters
comprise:
a speed of the vehicle, a throttle status of the vehicle, a braking status of
25 the vehicle, a state of charge (SoC) of a battery of the vehicle, and a gradient of
elevation of a terrain on which the vehicle is traveling.
8. The system as claimed in claim 1,
wherein the first power source (110) is an Internal Combustion Engine
30 (ICE); and
wherein the second power source (112) is a Motor Generator Unit (MGU).

9. The system as claimed in claim 8, wherein the plurality of drive modes of the
vehicle comprises a set of MGU drive modes comprising:
a first MGU drive mode, a second MGU drive mode, and a third MGU
5 drive mode,
wherein a gear ratio associated with the second MGU drive mode is greater than a gear ratio associated with the third MGU drive mode, and wherein a gear ratio associated with the first MGU drive mode is greater than the gear ratio associated with the second MGU drive mode. 10
10. The system as claimed in claim 9,
wherein for the first MGU drive mode,
the first clutch (C0) is unengaged, thereby, the first sun gear
(102A) is decoupled from the first power source (110);
15 the second clutch (C1) is unengaged, thereby, the ring gear (106) is
decoupled from the first power source (110);
the third clutch (C2) is engaged, thereby, the rotation of the ring gear (106) is fixed;
the fourth clutch (C3) is unengaged, thereby, the rotation of the
20 first sun gear (102A) and the second sun gear (104A) is free;
the fifth clutch (C4) is engaged, thereby, the first sun gear (102A) is coupled with the second power source (112); and
the sixth clutch (C5) is unengaged, thereby, the second sun gear (104A) is decoupled from the second power source (112). 25
11. The system as claimed in claim 9,
wherein for the second MGU drive mode,
the first clutch (C0) is unengaged, thereby, the first sun gear
(102A) is decoupled from the first power source (110);
30 the second clutch (C1) is unengaged, thereby, the ring gear (106) is
decoupled from the first power source (110);

the third clutch (C2) is engaged, thereby, the rotation of the ring gear (106) is fixed;
the fourth clutch (C3) is unengaged, thereby, the rotation of the
first sun gear (102A) and the second sun gear (104A) is free;
5 the fifth clutch (C4) is unengaged, thereby, the first sun gear
(102A) is decoupled from the second power source (112); and
the sixth clutch (C5) is engaged, thereby, the second sun gear (104A) is coupled with the second power source (112).
10 12. The system as claimed in claim 9,
wherein for the third MGU drive mode,
the first clutch (C0) is unengaged, thereby, the first sun gear (102A) is decoupled from the first power source (110);
the second clutch (C1) is unengaged, thereby, the ring gear (106) is
15 decoupled from the first power source (110);
the third clutch (C2) is unengaged, thereby, the rotation of the ring gear (106) is free;
the fourth clutch (C3) is unengaged, thereby, the rotation of the
first sun gear (102A) and the second sun gear (104A) is free;
20 the fifth clutch (C4) is engaged, thereby, the first sun gear (102A)
is coupled with the second power source (112); and
the sixth clutch (C5) is engaged, thereby, the second sun gear (104A) is coupled with the second power source (112).
25 13. The system as claimed in claim 8, wherein the plurality of drive modes of the
vehicle comprises a set of ICE drive modes comprising:
a first ICE drive mode, a second ICE drive mode, a third ICE drive mode, and a fourth ICE drive mode,
wherein a gear ratio associated with the third ICE drive mode is greater
30 than a gear ratio associated with the fourth ICE drive mode, wherein a gear ratio
associated with the second ICE drive mode is greater than the gear ratio

associated with the third ICE drive mode, and wherein a gear ratio associated with the first ICE drive mode is greater than the gear ratio associated with the second ICE drive mode.
5 14. The system as claimed in claim 13,
wherein for the first ICE drive mode,
the first clutch (C0) is engaged, thereby, the first sun gear (102A) is coupled with the first power source (110);
the second clutch (C1) is unengaged, thereby, the ring gear (106) is
10 decoupled from the first power source (110);
the third clutch (C2) is engaged, thereby, the rotation of the ring gear (106) is fixed;
the fourth clutch (C3) is unengaged, thereby, the rotation of the
first sun gear (102A) and the second sun gear (104A) is free;
15 the fifth clutch (C4) is unengaged, thereby, the first sun gear
(102A) is decoupled from the second power source (112); and
the sixth clutch (C5) is unengaged, thereby, the second sun gear (104A) is decoupled from the second power source (112).
20 15. The system as claimed in claim 14,
wherein the processor-executable instructions cause the processor to trigger the first ICE drive mode of the plurality of drive modes, when:
the speed of the vehicle is more than 45 kilometres per hour
(KPH), the SOC is more than 95 percent, and the throttle status of the
25 vehicle is more than 70 percent.
16. The system as claimed in claim 13,
wherein for the second ICE drive mode,
the first clutch (C0) is unengaged, thereby, the first sun gear
30 (102A) is decoupled from the first power source (110);

the second clutch (C1) is engaged, thereby, the ring gear (106) is coupled with the first power source (110);
the third clutch (C2) is unengaged, thereby, the rotation of the ring
gear (106) is free;
5 the fourth clutch (C3) is engaged, thereby, the rotation of the first
sun gear (102A) and the second sun gear (104A) is fixed;
the fifth clutch (C4) is unengaged, thereby, the first sun gear (102A) is decoupled from the second power source (112); and
the sixth clutch (C5) is engaged, thereby, the second sun gear
10 (104A) is coupled with the second power source (112).
17. The system as claimed in claim 16,
wherein the processor-executable instructions cause the processor to
trigger the second ICE drive mode of the plurality of drive modes, when:
15 the speed of the vehicle is more than 80 kilometres per hour
(KPH), the SOC is less than 95 percent, and the throttle status of the vehicle is more than 70 percent.
18. The system as claimed in claim 13,
20 wherein for the third ICE drive mode,
the first clutch (C0) is unengaged, thereby, the first sun gear (102A) is decoupled from the first power source (110);
the second clutch (C1) is engaged, thereby, the ring gear (106) is
coupled with the first power source (110);
25 the third clutch (C2) is unengaged, thereby, the rotation of the ring
gear (106) is free;
the fourth clutch (C3) is engaged, thereby, the rotation of the first sun gear (102A) and the second sun gear (104A) is fixed;
the fifth clutch (C4) is engaged, thereby, the first sun gear (102A)
30 is coupled with the second power source (112); and

the sixth clutch (C5) is unengaged, thereby, the second sun gear (104A) is decoupled from the second power source (112).
19. The system as claimed in claim 18,
5 wherein the processor-executable instructions cause the processor to
trigger the third ICE drive mode of the plurality of drive modes, when:
the speed of the vehicle is more than 110 kilometres per hour
(KPH), the SOC is less than 95 percent, and the throttle status of the
vehicle is more than 70 percent; or
10 the speed of the vehicle is more than 80 KPH, the SOC is less than
95 percent, and the throttle status of the vehicle is less than 70 percent.
20. The system as claimed in claim 13,
wherein for the fourth ICE drive mode,
15 the first clutch (C0) is engaged, thereby, the first sun gear (102A)
is coupled with the first power source (110);
the second clutch (C1) is engaged, thereby, the ring gear (106) is coupled with the first power source (110);
the third clutch (C2) is unengaged, thereby, the rotation of the ring
20 gear (106) is free;
the fourth clutch (C3) is unengaged, thereby, the rotation of the first sun gear (102A) and the second sun gear (104A) is free;
the fifth clutch (C4) is unengaged, thereby, the first sun gear
(102A) is decoupled from the second power source (112); and
25 the sixth clutch (C5) is unengaged, thereby, the second sun gear
(104A) is decoupled from the second power source (112).
21. The system as claimed in claim 20,
wherein the processor-executable instructions cause the processor to
30 trigger the fourth ICE drive mode of the plurality of drive modes, when:

the speed of the vehicle is more than 145 KPH and SOC is less than 95 percent, or
the speed of the vehicle is more than 110 KPH, the SOC is less
than 95 percent, and the throttle status of the vehicle is less than 70
5 percent.
22. The system as claimed in claim 8, wherein the plurality of drive modes of the
vehicle comprises a set of hybrid drive modes comprising:
a first hybrid drive mode, a second hybrid drive mode, a third hybrid drive
10 mode, and a fourth hybrid drive mode,
wherein a gear ratio associated with the third hybrid drive mode is greater
than a gear ratio associated with the fourth hybrid drive mode, wherein a gear
ratio associated with the second hybrid drive mode is greater than the gear ratio
associated with the third hybrid drive mode, and wherein a gear ratio associated
15 with the first hybrid drive mode is greater than the gear ratio associated with the
second hybrid drive mode.
23. The system as claimed in claim 22,
wherein for the first hybrid drive mode,
20 the first clutch (C0) is engaged, thereby, the first sun gear (102A)
is coupled with the first power source (110);
the second clutch (C1) is unengaged, thereby, the ring gear (106) is decoupled from the first power source (110);
the third clutch (C2) is engaged, thereby, the rotation of the ring
25 gear (106) is fixed;
the fourth clutch (C3) is unengaged, thereby, the rotation of the first sun gear (102A) and the second sun gear (104A) is free;
the fifth clutch (C4) is unengaged, thereby, the first sun gear
(102A) is decoupled from the second power source (112); and
30 the sixth clutch (C5) is engaged, thereby, the second sun gear
(104A) is coupled with the second power source (112).

24. The system as claimed in claim 22,
wherein for the second hybrid drive mode,
the first clutch (C0) is unengaged, thereby, the first sun gear
5 (102A) is decoupled from the first power source (110);
the second clutch (C1) is engaged, thereby, the ring gear (106) is coupled with the first power source (110);
the third clutch (C2) is unengaged, thereby, the rotation of the ring
gear (106) is free;
10 the fourth clutch (C3) is unengaged, thereby, the rotation of the
first sun gear (102A) and the second sun gear (104A) is free;
the fifth clutch (C4) is engaged, thereby, the first sun gear (102A) is coupled with the second power source (112); and
the sixth clutch (C5) is engaged, thereby, the second sun gear
15 (104A) is coupled with the second power source (112).
25. The system as claimed in claim 24,
wherein the processor-executable instructions cause the processor to
trigger the second hybrid drive mode of the plurality of drive modes, when:
20 the speed of the vehicle is more than 45 KPH, the SOC is more
than 95 percent, and the throttle status of the vehicle is less than 70 percent.
26. The system as claimed in claim 22,
25 wherein for the third hybrid drive mode,
the first clutch (C0) is unengaged, thereby, the first sun gear (102A) is decoupled from the first power source (110);
the second clutch (C1) is engaged, thereby, the ring gear (106) is
coupled with the first power source (110);
30 the third clutch (C2) is unengaged, thereby, the rotation of the ring
gear (106) is free;

the fourth clutch (C3) is unengaged, thereby, the rotation of the first sun gear (102A) and the second sun gear (104A) is free;
the fifth clutch (C4) is engaged, thereby, the first sun gear (102A)
is coupled with the second power source (112); and
5 the sixth clutch (C5) is unengaged, thereby, the second sun gear
(104A) is decoupled from the second power source (112).
27. The system as claimed in claim 26,
wherein the processor-executable instructions cause the processor to
10 trigger the third hybrid drive mode of the plurality of drive modes, when:
the speed of the vehicle is more than 145 KPH, the SOC is more than 95 percent.
the speed of the vehicle is more than 110 KPH, the SOC is more
than 95 percent, and the throttle status of the vehicle is less than 70
15 percent.
28. The system as claimed in claim 22,
wherein for the fourth hybrid drive mode,
the first clutch (C0) is unengaged, thereby, the first sun gear
20 (102A) is decoupled from the first power source (110);
the second clutch (C1) is engaged, thereby, the ring gear (106) is coupled with the first power source (110);
the third clutch (C2) is unengaged, thereby, the rotation of the ring
gear (106) is free;
25 the fourth clutch (C3) is unengaged, thereby, the rotation of the
first sun gear (102A) and the second sun gear (104A) is free;
the fifth clutch (C4) is unengaged, thereby, the first sun gear (102A) is decoupled from the second power source (112); and
the sixth clutch (C5) is engaged, thereby, the second sun gear
30 (104A) is coupled with the second power source (112).

29. The system as claimed in claim 8, wherein the plurality of drive modes
comprise:
a start-and-idle mode in which,
the first clutch (C0) is unengaged, thereby, the first sun gear
5 (102A) is decoupled from the first power source (110);
the second clutch (C1) is engaged, thereby, the ring gear (106) is coupled with the first power source (110);
the third clutch (C2) is unengaged, thereby, the rotation of the ring
gear (106) is free;
10 the fourth clutch (C3) is unengaged, thereby, the rotation of the
first sun gear (102A) and the second sun gear (104A) is free;
the fifth clutch (C4) is engaged, thereby, the first sun gear (102A) is coupled with the second power source (112); and
the sixth clutch (C5) is unengaged, thereby, the second sun gear
15 (104A) is decoupled from the second power source (112).
30. The system as claimed in claim 8, wherein the plurality of drive modes
comprise:
an idle mode in which,
20 the first clutch (C0) is unengaged, thereby, the first sun gear
(102A) is decoupled from the first power source (110);
the second clutch (C1) is unengaged, thereby, the ring gear (106) is decoupled from the first power source (110);
the third clutch (C2) is unengaged, thereby, the rotation of the ring
25 gear (106) is free;
the fourth clutch (C3) is unengaged, thereby, the rotation of the first sun gear (102A) and the second sun gear (104A) is free;
the fifth clutch (C4) is unengaged, thereby, the first sun gear
(102A) is decoupled from the second power source (112); and
30 the sixth clutch (C5) is unengaged, thereby, the second sun gear
(104A) is decoupled from the second power source (112).

31. A method of controlling drive modes in a hybrid drivetrain (100), the method comprising:
receiving one or more parameters associated with a vehicle corresponding
5 to a current running state of the vehicle;
selecting a drive mode from a plurality of drive modes, based on the one or more parameters; and
triggering at least one of a plurality of actuators to configure respective
clutches of a plurality of clutches in an engaged configuration, to selectively
10 couple a first sun gear (102A) and a ring gear (106) with a first power source
(110), and selectively couple the first sun gear (102A) and a second sun gear (104A) with a second power source (112), to thereby achieve the plurality of drive modes,
wherein the first sun gear (102A) is coupled with a first set of
15 planetary gears (102B) of a first epicyclic gear assembly (102),
wherein the second sun gear (104A) is coupled with a second set of planetary gears (104B) of a second epicyclic gear assembly (104),
wherein a planet carrier assembly (108) is coupled to a set of
wheels of the vehicle, and the first set of planetary gears (102B) and the
20 second set of planetary gears (104B) are rotatably coupled to the planet
carrier assembly (108), and
wherein the ring gear (106) is engaged with each of the first set of planetary gears (102B) and the second set of planetary gears (104B).
25 32. The method as claimed in claim 31, wherein the one or more parameters
comprise:
a speed of the vehicle, a throttle status of the vehicle, a braking status of
the vehicle, a state of charge (SoC) of a battery of the vehicle, and a gradient of
elevation of a terrain on which the vehicle is traveling.
30
33. A vehicle comprising:

a set of drive wheels to impart a drive to the vehicle; a first power source (110); a second power source (112); and
a hybrid drivetrain (100) configured to selectively couple at least one of
5 the first power source (110) and the second power source (112) with the set of
drive wheels, the hybrid drivetrain (100) comprising:
a first epicyclic gear assembly (102) comprising: a first sun gear (102A); and
a first set of planetary gears (102B), each of the first set of
10 planetary gears (102B) engaged with the first sun gear (102A);
a second epicyclic gear assembly (104); a second sun gear (104A); and
a second set of planetary gears (104B), each of the second set of
planetary gears (104B) engaged with the second sun gear (104A);
15 a ring gear (106) engaged with each of the first set of planetary gears
(102B) and the second set of planetary gears (104B);
a planet carrier assembly (108) coupled to the set of wheels, wherein the
first set of planetary gears (102B) and the second set of planetary gears (104B) are
rotatably coupled to the planet carrier assembly (108); and
20 a plurality of clutches configured to selectively couple the first sun gear
(102A) and the ring gear (106) with the first power source (110), and selectively
couple the first sun gear (102A) and the second sun gear (104A) with the second
power source (112), to obtain a plurality of drive modes of the vehicle, wherein in
each of the plurality of drive modes, the vehicle is driven by the first power source
25 (110), or the second power source (112), or a combination thereof.
34. The vehicle as claimed in claim 33, wherein the plurality of clutches comprises:
a first clutch (C0) configured to selectively couple the first sun gear
30 (102A) with the first power source (110);

a second clutch (C1) configured to selectively couple the ring gear (106) with the first power source (110);
a third clutch (C2) configured to selectively fix rotation of the ring gear
(106);
5 a fourth clutch (C3) configured to selectively fix rotation of the first and/or
second sun gear (104A);
a fifth clutch (C4) configured to selectively couple the first sun gear (102A) with the second power source (112); and
a sixth clutch (C5) configured to selectively couple the second sun gear
10 (104A) with the second power source (112).
35. The vehicle as claimed in claim 33 comprising:
a first shaft (114A) coupled with the first sun gear (102A);
a second shaft (114B) coupled with the second sun gear (104A); and
15 a third shaft (114C) coupled with the ring gear (106),
wherein the first shaft (114A), the second shaft (114B), and the third shaft (114C) are concentric; and
wherein the plurality of clutches is configured to selectively couple
the first sun gear (102A) with the first power source (110) and the second
20 power source (112), via the first shaft (114A),
wherein the plurality of clutches is configured to selectively couple the second sun gear (104A) with the second power source (112), via the second shaft (114B), and
wherein the plurality of clutches is configured to selectively couple
25 the ring gear (106) with the first power source (110), via the third shaft
(114C).