TECHNICAL FIELD
[0001] The present subject matter relates generally to hybrid vehicles
incorporating an internal combustion engine, and a traction motor and more particularly, but not exclusively, to a control system and method for managing the power of the hybrid vehicles.
BACKGROUND
[0002] Generally, a hybrid vehicle comprises of an internal combustion (IC)
engine and a traction motor for powering the vehicle. The IC engine installed on ' such hybrid vehicle uses gasoline/fuel as any other conventional IC engine. A '"r" starter motor is used to crank the IC engine. The traction motor is powered by an on board auxiliary power source. The hybrid vehicle being operated using either the IC engine, or the traction motor, or the IC engine and the traction motor jointly. The user can operate the hybrid vehicle in any one of the three modes as required namely an engine mode, an electric mode, and a hybrid mode. The hybrid mode further comprises of a hybrid power mode and a hybrid economy mode. In the hybrid power mode, both the IC engine, and the traction motor set up are operated jointly. In the hybrid economy mode, the IC engine, and the traction motor are operated alternatively. If the user wants more power, the vehicle can be operated in the hybrid power mode.
BRIEF DESCRIPTION OF THE DRAWINGS

V
[0003] The detailed description is described with reference to the
accompanying figures. The same numbers are used throughout the drawings to
reference like features and components.
[0004] Fig, 1 illustrates a left side view of an exemplary vehicle, in
accordance with an embodiment of the present subject matter.
[0005] Fig. 2 (a) illustrates a component level block diagram of a hybrid
control system, in accordance with an embodiment of the present subject matter.
[0006] Fig. 1 (b) illustrates a circuit level block diagram of the hybrid
control system
[0007] Fig. 3 illustrates the flow chart for the method of working of the
hybrid control unit, in accordance with the embodiment of the present subject
matter.
[0008] Fig. 4 (a) illustrates a left side view of a vehicle installed with the
hybrid control system, in accordance with an embodiment of the present subject
matter.
[0009] Fig. 4 (b) illustrates a right side perspective view of the frame
assembly with parts laid thereon.
[00010] Fig. 4 (c) illustrates a right side perspective view of the frame
assembly.
DETAILED DESCRIPTION
[00011] Typically, the user can operate the hybrid vehicle in any one of three
modes namely an engine mode, an electric mode, and a hybrid mode. The hybrid vehicle has plurality of power source(s) including a magneto or the traction motor

_or the auxiliary power source. A battery or a fuel cell can be an auxiliary power source in the vehicle. Further, the vehicle has various electrical/electronic loads (hereafter referred to as 'loads'), which are powered by- either of the aforementioned plurality of power source(s).
[00012] Generally, in the hybrid vehicle, the loads are driven by dual voltage
system. A rectifier and regulator (RR) unit for regulating the alternating current
voltage generated by the magneto, and another DC-DC converter unit for
regulating back EMF voltage of the traction motor, and the battery voltage.
Generally, a brush less DC (BLDC) motor is used as traction motor.
[00013] The magneto is functional and generates the alternating current
voltage only when the IC engine is operated. Whereas, the back EMF is generated by the traction motor only when it is not used to drive the wheel(s). When the vehicle is operated in engine mode, the magneto generates voltage that is fed to the RR unit, which regulates the generated voltage and supplies to the loads. In engine mode, even the DC-DC converter is functional to partially drive loads by . taking input from the auxiliary power source. While in electric mode, the traction motor and the loads are driven by the DC-DC converter. In hybrid mode, both IC engine and the traction motor are operating, and the loads are driven by both the DC-DC converter and the RR unit. However, operation of both the RR unit and DC-DC converter results in wastage of power. Moreover, a protection circuit is used for proper operation of RR unit and DC-DC converter, which makes the system bulky. Further, the hybrid vehicle when operated in the engine mode, at lower speed of the vehicle, say at speeds less than 50 kilometers per hour (kmph),

if the voltage of battery is less than a pre-defined voltage, the back EMF generated by the traction motor is used to charge the battery. The said speed limit can be varied with the control unit configuration. When the vehicle speed is high, say at speeds greater than 50 kmph, then the power output of the traction motor is high. Therefore, expensive circuitry is required to regulate the high power. Generally, this occurs in a system having permanent magnets, where higher electromagnetic fields are generated when rotations per minute of rotor is high resulting in generation of high currents.
[00014] Typically, beyond certain speed of the vehicle, the battery is isolated
from the high currents of the back EMF, and the battery is not charged. The generated power is supplied to DC-DC converter for driving the loads. Such isolation of the back EMF does not result in efficient use of power generated by the traction motor. Further, DC-DC converter is partially controlled by a controller unit but the RR unit is not operated by the controller unit. Two units, namely the RR unit, and DC-DC converter are not controlled efficiently in the known art. Thus, energy is wasted and not efficiently used. Moreover, the operation of magneto for driving the loads through RR unit also adds load on the engine. Also, at higher rotations per minute of the magneto, the load one the engine is high thereby the fuel economy of the vehicle is reduced.
[00015] Further, controller unit in the hybrid vehicle does not efficiently
manage the plurality of power source(s) of the vehicle. Such.inefficient use of power source(s) results in power loss. Moreover, use of separate RR unit and DC-DC converter unit increases the part count of the vehicle and thereby

mounting them is complex. Further, the length of the wiring harness increases, which in turn increases cost of the system.
[00016] Hence, an objective of present subject matter is to provide a hybrid
control system and a method thereof, for efficiently managing the power available from the plurality of power source(s) like an auxiliary power source, power from a magneto, and power from a traction motor available on the hybrid vehicle.
[00017] In an embodiment, the present subject matter is for a two-wheeled
vehicle. The vehicle comprises an internal combustion engine and a traction
motor. The.IC engine is swingably, connected to the frame assembly of ..the ..-,._...-
vehicle. A magneto is rotatably coupled to a crankshaft of the IC engine. The
traction motor is hub mounted to a rear wheel of the vehicle. In another
embodiment, the traction motor is rotatably coupled to rear wheel. Further, the
hybrid control system is mounted to a frame assembly of the vehicle.
[00018] In an embodiment, the hybrid control system of the present subject
matter determines. a load current and a power requirement of a one or more electrical/electronic load(s), thereby choosing the most efficient source, which are available, from the plurality of power source(s). Further, the hybrid control system determines operational state of the plurality of power source(s). Furthermore, the hybrid control system selectively connects at least power source of the plurality of power source(s) to a switch mode power supply (SMPS).
[00019] In an embodiment, the present subject matter uses a single regulator
and conditioning unit for regulating the output of the magneto. Also, the traction

motor output and the auxiliary power source are directly connected to the SMPS. Therefore, the need for a DC-DC converter is eliminated. Further, number of components is reduced. The system is compact. Also, the mounting complexity .and the length of the wiring harness are reduced. Also, the weight of the system is reduced.
[00020] Further, the present subject matter also enables driving the loads by
using a pulse width modulation (PWM) with variable duty cycle, which is performed by the SMPS, depending on at least one vehicle parameter(s) including vehicle speed, the time of operation, the engine rotation per minute and the power required by the loads.
[00021] In an embodiment, the hybrid control system comprises a hybrid
control unit for determining the power or current required by the loads. In an embodiment, a closed loop is used. As, the loads on the vehicle draw variable current depending on the ON or OFF state of the load, the hybrid control system modifies a duty cycle of the output of the SMPS. For example, if the vehicle is in idle condition and if the headlamp is ON, the hybrid control system monitors the engine rpm and modifies the duty cycle of the SMPS output signal. Moreover, the hybrid control system identifies the mode of operation of the vehicle and determines the available power source(s) of the plurality of power source(s) by determining operational state of the plurality of power source(s). Further, the hybrid control system selects at least one power source(s) of the plurality of source(s), which are available. The hybrid control system selectively connects at least one power source of the plurality of power source(s) to the SMPS. The

hybrid control system regulates and rectifies power available from plurality of source(s), especially the output of magneto, thereby eliminating the need for separate RR unit in the vehicle. In another embodiment, a buck converter enables driving of the loads efficiently saving power.
[00022] In an embodiment, the hybrid control unit is mounted on a
step-through type vehicle at an optimal location. The hybrid control unit is mounted at the frame assembly and being disposed downwardly in an anterior portion of the seat. Further, the hybrid control system is disposed rearwardly of an under seat cover panel. As, the electrical components including magneto and traction motor require thick wires as they carry high currents. Therefore, the wiring harness is disposed in proximity to the electrical components thereby the length of the wiring harness required for connecting the hybrid control system to the traction motor and the magneto is kept optimal.. Further, a single wire connecting the auxiliary power source/battery is routed from any location of the vehicle to the hybrid control system. Further, the hybrid vehicle of the present subject matter enables ease of assembly, disassembly, and maintenance of the hybrid control system. Furthermore, the risk of rainwater disrupting the effective functioning of the hybrid control unit is eliminated. In another embodiment, a cooling vent is provided on the under seat cove for cooling the hybrid control system.
[00023] In an embodiment, a phase relay(s) are provided to prevent any
phase short of the traction motor. The phase relays used are normally closed (NC). In case of a short, the hybrid control system senses the short circuit or the high

current and energizes the relay coils to open the relay contacts thereby the traction motor is protected from phase short. Moreover, a short could occur in the path between the hybrid control system and phase relays. In order to minimize occurrence of short between the hybrid control system and the phase relays, the phase relays are disposed in proximity to hybrid control system.
[00024] Further, the hybrid control unit and method of the present subject
matter are not restricted to a step-through type vehicle. It can be incorporated in any hybrid vehicle provided with a traction motor and an internal combustion engine.
[00025] The aforementioned and other advantages of the present subject
matter would be described in a greater detail in conjunction with the figures in the following description.
[00026] Fig. 1 illustrates a left side .view of an exemplary vehicle 100, in accordance with an embodiment of the present subject matter. The vehicle 100 illustrated, has a step-through type frame assembly 105. The step-through type frame assembly 105 includes a head tube 105A, a main frame 105B. One or more rear tube(s) 105C extend inclinedly rearward from the main tube 105B. Further, -one or more front suspensions 110A connect a front wheel HOB, and a handlebar assembly HOC forming a steering assembly 110. The steering assembly 110 is rotatably connected through the head tube 105A. An IC engine 115 acts as a primary drive means for driving a rear wheel 120. Further, a traction motor 120, acts as a secondary drive means for driving the rear wheel 120. In a preferred embodiment, the traction motor 120 is hub mounted on the rear wheel 125. An on

board battery 170 (not shown) drives the traction motor 120. The IC engine 115 is mounted to a swing arm 130, which is swingably connected to the main frame 105B using a toggle link. The vehicle 100 is provided with plurality of body panels, mounted to the frame assembly 105, and the plurality of body panels includes a front panel 135A, a leg shield 135B, an under seat cover 135C and a pair of side panel 135C.
[00027] A front fender 140 is covering at least a portion of the front wheel 110A. A floorboard 145 is provided at step-through space provided rearwardly of the handle bar assembly HOC. A seat assembly 150 is mounted to the main frame 105B. A utility box (not shown) is disposed below the seat assembly 150. A fuel tank (not shown) is positioned below the utility box. A rear fender 155 is covering at least a portion of the rear wheel 125 and is disposed below the fuel tank. One or more rear suspension(s) 160 are provided in the rear portion of the vehicle 100 for comfortable ride. The vehicle 100 comprises of a one or more electrical/electronic load(s) 165 (hereafter referred to as 'load(s)') including components such as a * headlight 165A, a tail light 165B, a transistor controlled ignition (TCI) unit (not shown), an alternator (not shown), and a starter motor (not shown).
[00028] Fig, 2 (a) illustrates a block diagram of a hybrid control system, in accordance with an embodiment of the present subject matter. The hybrid vehicle 100 is provided with the hybrid control system 200. Further, the hybrid vehicle 100 has a plurality of power source(s) (170, 115A, 120) including on board battery 170 of 48 volts, a traction motor 120, and a magneto 115A. The magneto 115A is rotatably coupled to a crankshaft of the IC engine 115. Therefore, the

magneto 115A generates the alternating current (VI) when the engine 115 is functional. The on board battery 170 acts as an auxiliary power source The traction motor 120, which is coupled to the rear wheel 125, generates a voltage (V2) when the vehicle is operated in the engine mode, An alternating current (VI) is generated by the magneto 115A when the vehicle is operated in engine mode or hybrid mode. The battery 170, the magneto 115A, and the traction motor 120 are coupled to the hybrid control system 200. An ignition switch 175 is used to connect the battery 170 to the load(s) 165. The load(s) 165 include various electrical loads, for example, the headlamp 165A, the tail lamp 165B, the horn, and starter motor.
[00029] The battery 170 is charged by an external source. Further, the hybrid
control system 200 enables charging of the battery 170 from the voltage (V2) generated by the traction motor 120. However, when the vehicle-is operated at higher speed, say at speed greater than 50 kilometers per hour, the hybrid control system 200 isolates charging of the battery 170 thereby eliminating high currents generated by traction motor 120 from affecting the battery 170. The aforementioned speed limit varies with the hybrid control system configuration. Furthermore, the magneto 115A is selectively disabled to reduce load on the engine 115.
[00030] Fig. 2 (b) illustrates the circuit level block diagram of the hybrid
control system, in accordance with an embodiment. The magneto 115A generates an alternating current voltage (V2) when the IC engine 115 is operating. The voltage (V2) generated by magneto 115A is fed to the hybrid control system 200.

The back EMF (VI) generated by the traction motor 115, subject to mode of operation of the vehicle, is fed to the hybrid control- system 200. The battery is connected to the hybrid control system 200.
[00031] The hybrid control system 200 comprises a bridge rectifier 205 and
a pre-conditioning unit 210. The bridge rectifier 205 and the pre-conditioning circuit regulates and rectifies the alternating current generated by the magneto 115A. Further, the hybrid control system 200 is provided with a multi-pole contact switch 215 that connects at least one power source of the plurality of power source(s) (170, 115A, 120), which are available, through a switch mode power supply 220. An ignition switch 175 connects or disconnects the load(s) 165 from the hybrid control system 200. Further, the hybrid control system 200 is provided with a hybrid control unit 225.
[00032] The hybrid control system 200 is provided with the bridge rectifier
205, the pre-conditioning unit 210, the switch mode power supply 220, the hybrid control unit 225, and the multi-pole switch 220, making the system compact. Further, the need for a separate RR unit and DC-DC converter is eliminated. In addition, the wastage of power due to functioning of multiple components is also eliminated.
[00033] Fig. 3 illustrates a flow chart for a method for power management,
in accordance with an embodiment of the present subject matter. The method 300 is a closed loop control method. At step 305, the ignition switch 175 is turned on. The hybrid control unit 225 of the hybrid control system 200 is powered ON. At step 310A, the hybrid control unit 225 determines a load current required for

driving load(s) 165, depending on ON or OFF state of the loads 165. A change in state of the load(s), which is ON or OFF state, will also be sensed by the' hybrid control unit 225. At step 310B, the load power is determined by the hybrid control unit 225. At step 310C, the hybrid control system 200 may modify pulse width modulation signal through switch mode power supply unit 220, thereby varying the duty cycle as per vehicle condition. For example, if the vehicle is idling, which is identified by engine rpm, the hybrid control system 200 enables modification of the duty cycle thereby using the power efficiently. The headlamp 165A, if in ON state, is driven with low power. At step 315, the hybrid control unit 225 identifies the mode of operation of the vehicle, namely the engine mode, the hybrid mode, or the electric mode. Thereby, the hybrid control unit 225 will be determining operational state of the plurality of power source(s) (170, 115A, 120), depending upon the mode of operation of the vehicle. For example, in hybrid mode at least two power source(s) are available e.g. battery 170 and the magneto 115A. Furthermore, at step 320, the hybrid control unit 225 of the hybrid control system 200 determines the power available from each of the plurality of power source(s) (170, 115A, 120) and selectively connects at least one power source of more of the plurality of power source(s) (170, 115A, 120) to the SMPS (220) for driving the load(s) 165. At step 325A, the hybrid control system 200 matches the one or more of the plurality of power source (170,115A, 120) and at step 325B, through a multi-pole contact switch 215 at least one power source of the plurality of power source(s) (170, 115A, 120) are connected to SMPS 220. At step 325C, the hybrid control system 200 enables connecting of the multi-pole

contact switch 215 to the buck converter unit and PWM circuit. In another
embodiment, a SMPS is used. At step 330,. the loads 165 are efficiently driven by
at least one power source of the plurality of power source(s) (170,115A, 120).
[00034] Further, the alternating current output of the magneto 115A is
regulated and rectified by hybrid control system 200 using bridge rectifier 205 and
pre-conditioning unit 210. This is fed to the multi-pole contact switch 150.
[00035] Fig. 4 (a) illustrates a schematic right side view of a hybrid vehicle
with hybrid control system, in accordance with an embodiment of the present
subject matter. The hybrid vehicle 100 comprises a step-through type frame
assembly 105. The traction motor 120 is hub mounted to the rear wheel 125. The
hybrid control system 200 is mounted to,the frame assembly 105 and being
disposed downwardly in an anterior portion of the seat assembly 150. The engine
115 is swingably connected to the frame assembly 105 and disposed below the
seat assembly 150. The magneto 115A is mounted to the engine 115.
[00036] Further, the frame assembly comprises one or more rear tubes 105C
extending inclinedly rearward. In an embodiment, the TCI unit 405 is mounted to the pair of rear tubes 105C. An air filter assembly 330 are located below the seat assembly 150. Further, a utility box 410 is disposed below the seat assembly 150. Therefore, the hybrid control has a compact packaging. -
[00037] Fig. 4 (b) a left side perspective view of a frame assembly with parts
laid thereon. Fig. 4 (c) depicts a left side perspective view of the frame assembly. The present subject matter provides the hybrid control system for power management. Therefore, the hybrid control system 200 being disposed at an

optimal location that enables heat exchange for efficient functioning. The frame assembly includes the pair of rear tubes 105C extending inclinedly rearward from the main tube 105B. The storage compartment 410 is mounted to the pair of rear tubes 105C. A cross member 420 is provided on the pair of rear tubes 105C. The cross member 420 being disposed downwardly of the seat assembly and in an anterior portion of the seat assembly. Further, the cross member 420 is adapted to accommodate the hybrid control system.
[00038] In an embodiment, the cross member 420 is provide with a casing,
that covers at least a portion of the hybrid control system. In one embodiment, the
casing is integrally formed with the cross member 420. Thick wiring harness is
required to connect traction motor 120 and the magneto 115A. The hybrid vehicle
of the present subject enables use of minimal wiring harness, thereby reducing
cost of the system. Further, the hybrid control system is optimally mounted to the
cross member 420, which is least affected by rainwater and water clogging. In
addition, the under seat cover 135C (shown in Fig. 1) covers at least a portion of
the hybrid control system. In addition, the under seat cover 135C is provide with a
cooling vent (not shown) for cooling of the hybrid control system 200.
[00039] The phase relays 430 are used to prevent phase short of the traction
motor 120. Phase relays 430 are normally closed (NC). Further, in case of short, the hybrid control system 200 senses the higher currents and energizes the phase relay 430 to open the relay contacts. The traction motor 120 is protected from phase short. A short can still occur in the path between the hybrid control system 200 and phase relays 430 and generally, there is no protection in this area.

Therefore, hybrid control system 200 and phase relays 410 are placed in close proximity to each other to keep the wiring harness minimal thereby reducing the chances of short circuit.
[00040] Many modifications and variations of the present subject matter are
possible in the light of above disclosure. Therefore, within the scope of claims of the present subject matter, the present disclosure may be practiced other than as specifically described.

I/We claim:
1. A hybrid control system (200) for power management in a hybrid, vehicle
(100), said vehicle (100) comprising an internal combustion engine (115), a
magneto/(115A) coupled to a-crankshaft of said engine (115), a traction motor
(120) functionally coupled to a rear wheel (125) of the hybrid vehicle (100), said
vehicle having a plurality of power source(s) (170, 115A, 120) including an
auxiliary power source (170), the magneto (115A), and the traction motor (120),
the hybrid control system (200) comprising:
a hybrid control unit (225);
a bridge rectifier (205) and a pre-conditioning unit (210) for rectifying and regulating an alternating current voltage (VI), respectively, generated by the magneto (115A); and
a switch mode power supply (SMPS) (220) functionally connected to a one or more electrical/electronic load(s) (165) of the vehicle,
wherein
the hybrid control unit (225) selectively connects at least one power source of the plurality of power source(s) (170, 115A, 120) to the SMPS (220) for driving said load(s) (165) basing on at least one of a load current required by the one or more electrical/electronic load(s) (165) that are in ON state, and operational state of the plurality of power source(s) (170,115A, 120).
2. The hybrid control system. (200) of claim 1, wherein the hybrid control system (200) includes a multi-pole contact switch (215) for selectively connecting at least one power source of the plurality of power source(s) (170, 115A, 120) to the SMPS (220).
3. The hybrid control system (200) of claim 1, wherein the hybrid control unit (225) modifies duty cycle of output of the SMPS (220) depending on at least one vehicle parameter(s).

4. The hybrid control system (200) of claim 1 and 3, wherein the at least one vehicle parameter includes a rotations per minute of the engine, or a speed of the vehicle (100), or a state of charge of the auxiliary power source (170).
5. A method for power management in a hybrid vehicle (100), said vehicle comprising an internal combustion engine (115) and traction motor (125), wherein the hybrid vehicle (100) comprises of a plurality of power source(s) (170, 115A, 120) including an auxiliary power source (170), a magneto (115A) and a traction motor (120), said method comprising steps of:
determining a load current required by a one or more electrical/electronic load(s) (165) of said vehicle (100) by a hybrid control unit (225);
determining operational stateof the plurality of power source(s) (170,115A, 120); and
selectively connecting at least power source of the plurality of power source(s) (170, 115A, 120) to an SMPS (220) for driving the one or more electrical/electronic load(s) (165).
6.. The method of claim 5, wherein selectively connecting at least one power source of the plurality of power source(s) (170, 115A, 120) to the SMPS (220) includes selectively connecting at least one power source of the plurality power source(s) (170,115A, 120) through a multi pole contact switch (215) to the SMPS (220).
7. A hybrid vehicle having an internal combustion engine (115), a traction motor (120), and an auxiliary power source (170), said vehicle comprising:
a step-through type frame assembly (105), said frame assembly (105) includes a main tube (105B) extending rearward from a head tube (105A) and a pair of rear tubes (105C) extending inclinedly rearward from the main tube (105B);
a seat assembly (150) supported by the pair of rear tubes (105C); and

a hybrid control system (200) functionally coupled to said engine (115), the traction motor (120) and the auxiliary power source (170),
wherein
the hybrid control system (200) including a hybrid control unit (225), a bridge rectifier (205) and a pre-conditioning unit (210), and a switch mode power supply (SMPS) (220); and
the hybrid control system (200) being mounted to a cross member (420) that is connecting the pair of rear tubes (105C), and the cross member (420) being disposed downwardly forward portion of the seat assembly (150).
8. The hybrid vehicle of claim 7, wherein the cross member (420) being adapted to accommodate a one or more phase relay(s) (430) that are connecting the traction motor (120) to the hybrid control system (200), and said phase relay(s) (430) being disposed in proximity to the hybrid control system (200).