Claims:We claim:
1. An apparatus (10) for starting an engine of a vehicle having an automatic start-stop module, the apparatus (10) comprising:
a flywheel (12), comprising:
a wheel (14) connectable to a crankshaft (16) of the engine;
an epicyclic gear train (20), comprising:
a sun gear (22) rotatably mountable on the crankshaft (16) adjacent to the wheel (14);
an annular gear (24) rotatably mountable on the crankshaft (16) concentric to the sun gear (22); and
at least one planet gear (26) disposed between the sun gear (22) and the annular gear (24), wherein the at least one planet gear (26) is rotatably connected to the wheel (14); and
a mechanism (30) for selectively restraining rotation of the annular gear (24), the mechanism (30) is configured to:
allow rotation of the annular gear (24) when the engine is operated to stop condition by the automatic start-stop module; and
restrain the rotation of the annular gear (24) to assist starting of the engine when the automatic start-stop module generates a signal to start the engine.

2. The apparatus (10) as claimed in claim 1, wherein the at least one planet gear (26) is rotatably mounted on at least one shaft (14A) protruding from the wheel (14), such that rotation of the wheel (14) facilitates revolution of the at least one planet gear (26) around the sun gear (22).

3. The apparatus (10) as claimed in claim 1, wherein the sun gear (22) and the annular gear (24) are rotatably mountable on the crankshaft (16) through at least one bearing (22A, 24A).

4. The apparatus (10) as claimed in claim 1, wherein the mechanism (30) is configured to restrain the rotation of the annular gear (24) when the engine is not operated by the automatic start-stop module.

5. The apparatus (10) as claimed in claim 1, wherein the engine is operated to the stop condition by the automatic start-stop module, when the engine runs in an idle condition for a predetermined time.

6. The apparatus (10) as claimed in claim 1, wherein the mechanism (30) is operatively coupled to a control unit (40) of the vehicle, and the control unit (40) is configured to operate the mechanism (30) based on signals received from the automatic start-stop module.

7. The apparatus (10) as claimed in claim 1 comprises a starter motor (50), wherein, the starter motor (50) is coupled to the flywheel (12), and is configured to selectively operate the flywheel (12) to crank the engine.

8. A method for cranking an engine of a vehicle when the engine is operated by an automatic start-stop module, the method comprising:
operating, a mechanism (30), to a release condition by a control unit (40) to allow rotation of an annular gear (24) of a flywheel (12), when the engine is operated to stop condition by the automatic start-stop module, wherein the flywheel (12) comprises:
a wheel (14) connectable to a crankshaft (16) of the engine;
an epicyclic gear train (20), comprising:
a sun gear (22) rotatably mountable on the crankshaft (16) adjacent to the wheel (14);
the annular gear (24) rotatably mountable on the crankshaft (16) concentric to the sun gear (22); and
at least one planet gear (26) disposed between the sun gear (22) and the annular gear (24), wherein the at least one planet gear (26) is rotatably connected to the wheel (14);
and
operating, the mechanism (30), to an engaged condition by the control unit (40) to restrain the rotation of the annular gear (24) to assist cranking of the engine, when the automatic start-stop module generates a signal to start the engine.

9. The method as claimed in claim 8, wherein the engine is operated to the stop condition by the automatic start-stop module when the engine runs in an idle condition for a predetermined time.

10. The method as claimed in claim 8 comprises act of selectively operating a starter motor (50) of the vehicle by the control unit (40), to rotate the flywheel (12) to crank the engine.

11. A vehicle comprising an apparatus (10) to start an engine having an automatic start-stop module, as claimed in claim 1.
, Description:TECHNICAL FIELD
Present disclosure generally relates to field of Automobiles. Particularly, but not exclusively, the present disclosure relates to an internal combustion engine of an automobile. Further, embodiments of the present disclosure disclose an apparatus for starting an engine having an automatic start and stop module, and a method for cranking the engine when the engine is operated by the automatic start-stop module.

BACKGROUND
An Internal Combustion engine (I.C) is a prime mover which transfers energy produced by combustion of fuel to wheels to propel the vehicle. The I.C engine comprises an engine block having one or more cylinders in which reciprocating pistons operate. The heat released during combustion of charge in the cylinder exerts pressure on top portion of the piston to impart reciprocating motion. The reciprocating motion of the piston will be transformed into rotary motion of crankshaft which is connected to the piston through a connecting rod. Conventionally, the crankshaft carries a rotating mass called “flywheel” at one of its ends. The flywheel rotates with the crankshaft and provides the crankshaft with necessary power [or energy] for continuous rotation. In other words, the flywheel stores power [energy] from the crankshaft during power stroke of the engine, and rotates the crankshaft during the remaining strokes during engine operation. Thus, the flywheel may be regarded as an energy reservoir which retrieves and restores the rotary power from and to the crankshaft respectively.

The energy stored and delivered by the flywheel may be regarded as a result of moment of inertia acting on the flywheel and angular speed of the flywheel. The moment of inertia may be dependent on parameters like mass and radius of the flywheel, among several other parameters. During operation of the engine, the crankshaft runs at predefined angular speed during the power stroke, and the angular speed is comparatively lesser during the other strokes. In other words, the angular speed of a crankshaft is continuously fluctuating or pulsating during engine operation from one stroke to another. The flywheel, therefore, is intended to effectively give back absorbed power to the crankshaft to resist changes in angular speed of the crankshaft. The flywheel also serves the purpose of damping out vibrations caused by variations in engine combustion.

With the advancement of technology in automotive industry and owing to stringent emission norms, some of the modern vehicles are employed with automatic start stop modules. In such vehicles, the automatic start-stop module continuously monitors various parameters including vehicle speed, gear lever position, clutch position, idle time, and the like, and operate the engine to stop condition if the vehicle is running in idle condition for more than predetermined time. Such feature in the vehicle helps to improve fuel efficiency, and reduce emissions from the engine by automatically operating the engine to stop condition, for example, in traffic signals. Also, the automatic start-stop module assists in automatic start of the engine, when the user operates the clutch pedal to move the vehicle from halt condition. In conventional vehicles, the automatic start-stop module provides signal to a starter motor, which may be directly or indirectly coupled with the flywheel. The starter motor is operated to deliver force to the flywheel, which in turn, rotates the crankshaft for cranking the engine. However, the use of starter motor for cranking the engine draws power from battery of the vehicle, and if the starter motor is operated frequently by the automatic start-stop control module, the power from the battery will be frequently drawn. Hence, some of the conventional vehicles having automatic start-stop module are employed with heavy batteries for serving this function. However, the use of heavy batteries increases load on the alternator, and increases bulkiness and weight of the vehicle.

The present disclosure is directed to address one or more problems as discussed above.

The information disclosed in the background of the disclosure section is only for enhancement of understanding of the general background of the invention, and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

SUMMARY
The one or more drawbacks associated with existing engines as described in the background are overcome and additional advantages are provided through the apparatus as claimed in the present disclosure. Additional features and advantages are realized through the technicalities of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered to be a part of the claimed disclosure.

In one non-limiting embodiment of the present disclosure, there is provided an apparatus for starting an engine of a vehicle having an automatic start-stop module. The apparatus comprises a flywheel, comprising a wheel connectable to a crankshaft of the engine, and an epicyclic gear train. The epicyclic gear train comprises a sun gear rotatably mountable on the crankshaft adjacent to the wheel, an annular gear rotatably mountable on the crankshaft concentric to the sun gear, and at least one planet gear disposed between the sun gear and the annular gear. The at least one planet gear is rotatably connected to the wheel. Further, a mechanism is provided for selectively restraining rotation of the annular gear. The mechanism is configured to allow rotation of the annular gear when the engine is operated to stop condition by the automatic start-stop module, and restrain the rotation of the annular gear to assist starting of the engine when the automatic start-stop module generates a signal to start the engine.

In an embodiment of the present disclosure, the at least one planet gear is rotatably mounted on at least one shaft protruding from the wheel, such that rotation of the wheel facilitates revolution of the at least one planet gear around the sun gear.

In an embodiment of the present disclosure, the sun gear and the annular gear are rotatably mountable on the crankshaft through at least one bearing.

In an embodiment of the present disclosure, the mechanism is configured to restrain the rotation of the annular gear when the engine is not operated by the automatic start-stop module.

In an embodiment of the present disclosure, the engine is operated to the stop condition by the automatic start-stop module, when the engine runs in an idle condition for a predetermined time.

In an embodiment of the present disclosure, the mechanism is operatively coupled to a control unit of the vehicle, and the control unit is configured to operate the mechanism based on signals received from the automatic start-stop module.

In an embodiment of the present disclosure, the apparatus comprises a starter motor coupled to the flywheel, and the starter motor is configured to selectively operate the flywheel to crank the engine.

In another non-limiting embodiment of the present disclosure, there is provided a method for cranking an engine of a vehicle when the engine is operated by an automatic start-stop module. The method comprises operating, a mechanism, to a release condition by a control unit to allow rotation of an annular gear of a flywheel, when the engine is operated to stop condition by the automatic start-stop module. The flywheel comprises a wheel connectable to a crankshaft of the engine, and an epicyclic gear train. The epicyclic gear train comprises a sun gear rotatably mountable on the crankshaft adjacent to the wheel. Further, the annular gear is rotatably mountable on the crankshaft concentric to the sun gear, and at least one planet gear is disposed between the sun gear and the annular gear. The at least one planet gear is rotatably connected to the wheel. Further, the method comprises operating, the mechanism to an engaged condition by the control unit to restrain the rotation of the annular gear, when the automatic start-stop module generates a signal to start the engine.

In an embodiment of the present disclosure, the engine is operated to the stop condition by the automatic start-stop module when the engine runs in an idle condition for a predetermined time.

In an embodiment of the present disclosure the method comprises act of selectively operating a starter motor of the vehicle by the control unit to rotate the flywheel, to crank the engine.

It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiments may be combined together to form a further embodiment of the disclosure.

The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The novel features and characteristics of the disclosure are set forth in the appended description. The disclosure itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings. One or more embodiments are now described, by way of example only, with reference to the accompanying drawings wherein like reference numerals represent like elements and in which:

FIG. 1 illustrates exploded perspective view of an apparatus for starting an engine, according to an embodiment of the present disclosure.

FIGS. 2A and 2B illustrate sectional side view and sectional top view respectively of a flywheel of the apparatus of FIG. 1 in assembled condition, according to an embodiment of the present disclosure.

FIG. 3A illustrates perspective view of a wheel of the flywheel shown in FIGS. 2A and 2B with a sun gear and planet gears, according to an embodiment of the disclosure.

FIG. 3B illustrates sectional side view of the wheel of FIG. 3A along section B-B.

FIG. 3C illustrates perspective view of the annular gear of the flywheel shown in FIGS. 2A and 2B.

FIG. 3D illustrates front view of the annular gear of FIG. 3C engaged with the planet gears shown in FIGS. 2A and 2B.

FIG. 4 illustrates schematic views of the apparatus operating in a sequence to assist starting of an engine, according to an embodiment of the present disclosure.

FIG. 5 shows a flowchart illustrating sequence of stages involved in cranking an engine of a vehicle having an automatic start-stop module, according to an exemplary embodiment of the present disclosure.

FIG. 6 shows a graph illustrating variation of engine speed (in RPM) as a function of time, according to an exemplary embodiment of the present disclosure.

The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the systems, apparatuses and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAILED DESCRIPTION
The foregoing has broadly outlined the features and technical advantages of the present disclosure in order that the detailed description of the disclosure that follows may be better understood. Additional features and advantages of the disclosure will be described hereinafter which form the subject of the claims of the disclosure. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the scope of the disclosure as set forth in the appended claims. The novel features which are believed to be characteristic of the disclosure, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present disclosure.

Embodiments of the present disclosure disclose an apparatus for starting an engine having an automatic start-stop module. The apparatus may be configured to automatically start and stop engine of the vehicle without the aid of starter motor, when the automatic start-stop module generates a signal to start the engine. The apparatus employs a flywheel of the vehicle for cranking the engine. The flywheel comprises a wheel which is connectable to a crankshaft of the engine. The flywheel also includes an epicyclic [or planetary] gear train which includes a sun gear and an annular gear, both of which may be rotatably mountable on the crankshaft adjacent to the wheel. The annular gear may be mounted concentric to the sun gear. In an embodiment of the present disclosure, the sun gear and the annular gear are rotatably mountable on the crankshaft through at least one bearing. Further, the epicyclic gear train comprises at least one planet gear disposed between the sun gear and the annular gear, such that the at least one planet gear meshes with both the sun gear and the annular gear. The at least one planet gear is rotatably connected to the wheel, such that the at least one planet gear may revolve around the sun gear when the wheel is set in rotation.

The apparatus also comprises a mechanism for selectively restraining rotation of the annular gear. The mechanism is configured to allow rotation of the annular gear when the engine is operated to stop condition by the automatic start-stop module, and then, restrain the rotation of the annular gear to assist starting of the engine when the automatic start-stop control generates a signal to start the engine from the stop condition. The mechanism may be operatively coupled to a control unit of the vehicle, and the control unit may operate the mechanism based on signals received from the automatic start-stop module. When the automatic start-stop module generates a signal to start an engine, the mechanism restrains the rotation of the annular gear, which transfers the motion to the wheel through the planet gear. The wheel in turn rotates the crank-shaft which results in cranking of the engine without aid of starter motor.

Embodiment of the disclosure also discloses a method for cranking an engine of a vehicle when the engine is operated by the automatic start-stop module. The method comprises acts of operating the mechanism to a release condition by a control unit of the vehicle, to allow rotation of an annular gear of a flywheel, when the automatic start-stop module operates the engine to a stop condition. The rotation of the annular gear stores the energy. When the automatic start-stop module generates a signal to start the engine, the mechanism may be operated to an engaged condition by the control unit to restrain the rotation of the annular gear. The action of restraining the rotation of the annular gear results in transfer of energy from the annular gear to the wheel through the planet gears. This results in rotation of the crankshaft to crank the engine.

Use of terms such as “comprises”, “comprising”, or any other variations thereof in the description, are intended to cover a non-exclusive inclusion, such that apparatus or method that comprises a list of components or steps does not include only those components or steps, but may include other components or steps not expressly listed or inherent to such setup or device or system or apparatus and method. In other words, one or more elements in an apparatus may be proceeded by “comprising… a” does not, without more constraints, preclude the existence of other elements or additional elements in the apparatus.

Reference will now be made to an apparatus and a method for starting an engine of a vehicle, and is explained with the help of figures. The figures are for the purposes of illustration only, and should not be construed as limitations on the apparatus and the method disclosed in the present disclosure. Wherever possible, referral numerals will be used to refer to the same or like parts.

FIG. 1 is an exemplary embodiment of the disclosure which illustrates exploded perspective view of an apparatus (10) for starting an engine [not shown] having an automatic start-stop module [not shown]. An engine, as known in the art, generates power and delivers it to transmission assembly [not shown] through a crankshaft (16). The transmission assembly, thereafter, delivers power to drive wheels for propelling the vehicle. The crankshaft (16) essentially gets power during the working stroke [or power stroke] of the engine, however, must run continuously to effectuate other strokes which constitute the engine cycle. In order to run the crankshaft (16) during remaining strokes, a flywheel (12) may be mounted on the crankshaft (16). The apparatus (10) of the instant invention employs energy stored by the flywheel (12) to start the engine, when the engine is operated by the automatic start-stop module. As depicted in FIG. 1, the flywheel (12) may be divided into two components or sub-assemblies. The first component is a wheel (14), and the second component or sub-assembly may be an epicyclic gear train (20). The wheel (14) of the flywheel (12) may be composed of a solid mass and is configured to drive the epicyclic gear train (20) to assist the engine cranking and engine starting when required. In an embodiment of the present disclosure, the wheel (14) may resemble a gear drive with teeth on its periphery, such that it can receive and transmit power from and to the components meshing with it. In an alternate embodiment, the wheel (14) serves as a planet carrier to drive one or more planet gears (26) constituting the epicyclic gear train (20), which will be described in detail later. The wheel (14) may also comprise a provision (14B) such as a hole or a bore to accommodate the crankshaft (16). The crankshaft (16) may be coupled with the wheel (14), such that the wheel (14) will rotate with the crankshaft (16) during rotation. The wheel (14) also includes one or more projections (14A), such as protruding shafts (14A) extending outwardly. The projections (14A) may be configured to accommodate the planet gears (26) of the epicyclic gear train (20).

The flywheel may also include an epicyclic gear train (20), comprising a sun gear (22), an annular gear and one or more planet gears. The sun gear (22) may be disposed at a central portion of the wheel (14), and may be rotatably mounted on the crankshaft (16) through a bearing (22A). The annular gear (24) [a ring gear with internal gear teeth] may be mounted on the crankshaft (16) concentric to the sun gear (22). In between the sun gear (22) and the annular gear (24), one or more planet gears (26) are disposed. The planet gears (26) simultaneously mesh with the sun gear (22) on one side and the annular gear (24) on the other side. Several gear ratios may be achieved by restraining different gears, and at the same time rotating other gears constituting the epicyclic gear train (20). As it can be seen in FIG. 1, the sun gear (22) and the annular gear (24) may be rotatably mounted on the crankshaft (16), while the planet gears (26) may be connected to the shafts (14A) protruding from the wheel (14) surface. In an embodiment of the present disclosure, the sun gear (22) and the annular gear (24) may be mounted on the crankshaft (16) through respective bearings to have relative motion between the drives (22, 24) and the crankshaft (16). For example, when the sun gear (22) is mounted on the crankshaft (16) through a rotary bearing, including but not limited to roller bearings, the sun gear (22) may be rotated relative to the shaft about the bearings. Thus, rotation of the sun gear (22) and the annular gear (24) may be independent of rotation of the crankshaft (16) due to the presence of bearings. In an embodiment of the present disclosure, the sun gear (22) may comprise a provision (22B) for accommodating a bearing (22A), and the sun gear (22) with bearing (22A) may be mounted on the crankshaft (16).

The apparatus (10) further comprises a mechanism (30) to selectively restrain the motion of annular gear (24) of the flywheel (12). In an embodiment of the disclosure, the mechanism (30) may be a braking assembly. The braking assembly may be operated by at least one of mechanical actuator, hydraulic actuators or pneumatic actuators. The mechanism (30) may be communicatively associated with the Electronic Control unit of the vehicle. The ECU may be configured to operate the mechanism based on the signals received from the automatic start-stop control module. The selective restraining of the annular gear (24) cranks the engine i.e. drives the crankshaft (16), to assist starting of the engine when the engine is to be started from temporary stop or standstill condition. In an embodiment of the present disclosure, the mechanism (30) may restrain rotation of the annular gear (24) of the flywheel (12) to start an engine, when the engine is temporarily brought to standstill after idling for a predetermined interval of time by the automatic start-stop module. For example, considering a scenario when the vehicle halts for more than predetermined time in a city traffic condition. During the halt, the engine runs in idle condition for some time, like 20 seconds, 25 seconds, 50 seconds, and so on. After certain duration, say 20 seconds, the automatic start-stop module of the vehicle may operate the engine to stop condition by cutting of the fuel supply or interrupting the spark generation. During such engine stop, the mechanism (30) may be configured to release the annular gear (24), thereby allowing it to rotate freely. The free rotation of the annular gear (24) retrieves energy from the crankshaft (16) and stores the energy. When the engine is to be started again to propel the vehicle, the automatic start-stop module generates and sends signals to perform the engine start operation. During this time, the mechanism (30) engages with the annular gear (24) to restrain the rotation of the annular gear (24). Restraining the angular motion of annular gear (24) results in transfer of energy from the annular gear (24) to the crankshaft (16) via the planet gears (26) and the wheel (14). The transfer of energy from the annular gear (24) to the wheel (14) provides the crankshaft (16) with necessary torque, to assist cranking of the engine for start.

FIGS. 2A and 2B are exemplary embodiments of the present disclosure which illustrate sectional side view and top view respectively of the flywheel (12) of the apparatus (10) in the assembled condition. The flywheel (12), as described in previous paragraphs, may have a split type arrangement where the wheel (14) serves as a primary component, and the epicyclic gear train (20) serves as a secondary component or sub-assembly. The wheel (14) may be fixed to the crankshaft (16) so that it rotates with the crankshaft (16) whenever the crankshaft (16) is set in motion. In an embodiment, the wheel (14) may be fixed to the crankshaft (16) through members like keys. In another embodiment, the wheel (14) fixed to the crankshaft (16) may serve as a primary flywheel to absorb and deliver power to the crankshaft (16) during engine operation.

Further, the shafts (14A) [alternatively referred to as “protruding pins” or simply “pins” throughout the specification] extending from the wheel (14) accommodates the planet gears (26) present in the epicyclic gear train (20). The planet gears (26) may be disposed between the sun gear (22) and the annular gear (24) [best shown in FIG. 1 and FIG. 3A]. The sun gear (22) and the annular gear (24) may be mounted on the crankshaft (16) such that they may rotate relative to the crankshaft (16). In an embodiment, the relative motion of the sun gear (22) and the annular gear (24) may be assisted by one or more bearings (22A, 24A), such as roller bearings among other types of rotary bearings. Thus, each of the sun gear (22) and the annular gear (24) may have one degree of freedom. The planet gear (26), which meshes with sun gear (22) as well as the annular gear (24) may rotate about the shafts (14A) of the wheel (14), and in addition, may revolve around the sun gear (22) depending on the constrains in the epicyclic gear train (20). This way, the planet gears (26) may have more than one degree of freedom. In an embodiment of the present disclosure, a first gear ratio may be obtained by arresting the annular gear (24) and by rotating the sun gear (22), which causes the planet gears (26) to rotate about the shafts (14A) and revolve around the sun gear (22). In this case, the output power may be derived from the wheel (14) which acts as a planet carrier. In another embodiment, the annular gear (24) may be released, so that upon rotation of the sun gear (22), the planet gears (26) rotate about the shafts (14A) and in turn drive the annular gear (24). The output power may be retrieved from the annular gear (24) in this case. In yet another embodiment, input rotation may be given to the annular gear (24), and power output may be obtained at the sun gear (22) or the wheel (14) depending on whether sun gear (22) is restrained or free to rotate.

Reference is now made to FIGS. 3A and 3B which illustrate perspective view of the wheel (14) assembled to sun gear (22) and planet gears (26), and sectional view along section B-B of FIG. 3A respectively. As shown in FIG. 3A, the sun gear (22) may be positioned adjacent and co-axial to the wheel (14), so that the crankshaft [as shown in FIGS. 2A and 2B] accommodates in the provision (14B) extending co-axially through the sun gear (22) and the wheel (14) along the crankshaft (16) axis A-A. The provision (14B) is best shown in FIG. 3B. The wheel (14) may rotate in unison with the crankshaft (16), while the sun gear (22) may rotate independently of the crankshaft (16). Further, as illustrated in FIG. 3A, the planet gears (26) may be mounted on the shafts (14A) [shown in FIG. 1] through bearings (26A) for allowing rotation of the planet gears (26) about the shafts (14A). In an embodiment of the present disclosure, the planet gear (26) and the sun gear (22) may have different number of teeth [or different diameters] to provide variable gear ratios. In an embodiment of the present disclosure, the wheel (14) may be driven by one or more starter motors (50) to input power to the crankshaft (16) for cranking. The starter motor (50) may be interfaced with a control unit (40) unit of the vehicle to receive signals whenever user desires to start the engine. In an embodiment of the present disclosure, the starter motor (50) may be connected to a power source, like a battery [not shown], to draw power and operate. In an alternate embodiment, the starter motor (50) may be reversed to operate as a generator to generate electrical energy, for example, during regenerative braking of the vehicle. The generated electrical energy may be stored in the battery to restore battery power. In an embodiment of the present disclosure, the starter motor (50) may include shaft mounted with a gear drive to deliver power to the wheel (14). The starter motor (50) may be employed to transmit power [torque and angular speed] to the flywheel (12) to provide starting torque to the engine when engine is to be cranked for initial cranking.

FIGS. 3C and 3D are exemplary embodiments of the present disclosure which illustrate perspective view of the annular gear (24) and front view of the annular gear (24) assembled with planet gears (26) and the sun gear (22). The annular gear (24) comprises internal teeth which mesh with gears of the planet gears (26), as shown in FIG. 3C. Further, the annular gear (24) may be positioned adjacent to the wheel (14) such that the intermeshing sun gear (22) and the planet gears (26) are accommodated in the inner annular region of the annular gear (24), with planet gears (26) being mounted on the shafts (14A) of the wheel (14). The annular gear (24) also comprises a provision (24B), including but not limited to a hole or a bore, to accommodate the crankshaft (16) through bearing (24A).

FIGS. 4 and 5 are exemplary embodiment of the present disclosure which illustrate operation of the apparatus for cranking the engine when the automatic start-stop module generates a signal to start the engine. The stages 1-4 are illustrated with reference to different configurations of the apparatus (10) as shown in FIG. 4, while the method of operating the apparatus (10) for starting the engine i.e. the method for cranking the engine is evident from flowchart depicted in FIG. 5. Also, in the foregoing description, reference is made to an automatic start-stop module [not shown] of the vehicle. The automatic start-stop module may be employed in the vehicles, and may be configured to automatically start and stop the engine in long idle conditions to achieve better fuel efficiency and to reduce emissions. The automatic start-stop module may be associated with the Electronic Control Unit [ECU] of the vehicle, and may be configured to cut-off of the engine whenever engine operation is to be temporarily interrupted and resumed to achieve desired objectives, like saving fuel, minimizing power consumption, and so on. The automatic start-stop control which cuts-off the engine cycle either by interrupting the fuel supply or by interrupting spark ignition is known in the art, and is not explained in detail in the embodiments of the present disclosure. Now reference is made to FIG. 4 in conjunction with FIG. 5 to describe the technique by which the engine may be cranked by the apparatus (10) to achieve the start function.

Stage – 1: Normal driving condition
In normal driving condition, the engine may be cranked by operating the starter motor. Then, the engine develops power and drives the drive wheels to propel the vehicle. The automatic start-stop module does not take part in effectuating or disrupting the fuel supply or ignition, and allows the engine run in its normal cycle. During normal operation of the engine i.e. normal running condition of the vehicle, the mechanism (30) may be actuated by the Electronic Control Unit to restrain the rotation of the annular gear (24). As the crankshaft (16) is in motion due to running condition of the engine, the wheel (14) will be set in rotation by the crankshaft (16). The restrain on the annular gear (24), therefore, causes the planet gears (26) to revolve around the sun gear (22). The rotation of the wheel (14) and the planet gear (26) enables the flywheel (12) store energy as a result of moment of inertia and angular speed. In an embodiment of the present disclosure, the flywheel (12) stores kinetic energy which is a resultant of moment of inertia and angular speed of the flywheel (12) during rotation. The rotation of the wheel (14) and the planet gears (26) around the sun gear (22) may continue for some more duration even after the engine has come to a standstill condition, owing to moment of inertia in the flywheel (12).

Stages – 2 and 3: Engine stop after idling for predetermined time
When the vehicle is brought to halt, the engine runs in idle condition for some time. After a predetermined duration of idling has elapsed, for example 10 seconds, the automatic start-stop logic, the automatic start-stop module may automatically stop the engine. As explained earlier, the engine may be stopped either by cutting-off the fuel supply, or by disrupting the spark ignition. During the engine shut-off, the mechanism (30) may be actuated by the Electronic Control Unit to release the annular gear (24), allowing it to rotate freely. In other words, the mechanism may be operated to release condition. As the annular gear (24) is free to rotate, the power transmission takes place in the following order: crankshaft to wheel, wheel to planet gears, and through planet gears to the annular gear. In an embodiment of the present disclosure, when annular gear (24) is free to move, the planet gears (26) may not revolve around the sun, instead, may rotate about the shafts (14A). The power flow from crankshaft (16) to the annular gear (24) in the above-mentioned manner may continue until the crankshaft (16) comes to rest due to engine shut-off. The rotation of the annular gear (24) may further continue after the crankshaft (16) comes to rest. The annular gear (24), with the onset of rotational motion, starts storing rotational energy by virtue of its moment of inertia and angular speed. In an embodiment of the present disclosure, the energy stored in the epicyclic gear train (20) is proportional to difference in angular acceleration between the wheel (14) and the annular gear (24). In an embodiment of the present disclosure, the mechanism (30) may be identical to braking system, including but not limited to mechanical brakes, hydraulic brakes and pneumatic brakes which apply braking forces on the annular gear (24) to arrest its rotation. In another embodiment of the present disclosure, the mechanism (30) is operatively coupled with the control unit (40) of the vehicle to timely activate and deactivate the mechanism (24) to selectively engage and disengage with the annular gear (24).

Stage – 4: Automatic engine start from the stop condition when vehicle is to be propelled
Once the user intends to move the vehicle from the halt condition, the automatic start-stop module initiates the function of starting the engine. In an embodiment of the present disclosure, the user input may be provided through a clutch of the vehicle i.e. mechanism (30) may be activated by operating the clutch of the vehicle. When the automatic start-stop module generates signals to initiate engine start, the mechanism (30) may be actuated by the control unit to restrain the rotation of the annular gear (24), resulting in progressive stopping of the annular gear (24). The annular gear (24) which may gradually come to rest, transfers its energy to the planet gears (26). At the same time, the annular gear (24), which can no longer rotate, forces the planet gears (26) to start revolving around the sun gear (22). The revolution of the planet gears (26) in turn causes rotation of the wheel (14), thereby effecting the rotation of the crankshaft (16). The rotation of the crankshaft (16) results in engine cranking, and allows the automatic start-stop module to initiate the engine cycle through fuel injection or ignition. The energy transmitted by the restrained annular gear (24) to the crankshaft (16) through the planet gears (26) and the wheel (14) will drive the crankshaft (16) with ample power [torque and angular speed] required for cranking and starting the engine.

In some embodiments of the disclosure, the ECU may determine the torque availability in the crankshaft (16), when the mechanism (30) restrains the annular gear (24). When the torque is found to be less than the minimum torque required for cranking the engine, the ECU may operate the starter motor (50) to assist cranking of the engine.

FIG. 6 is an embodiment of the present disclosure which illustrates an exemplary graph showing the variation of angular speed [in RPM] of the flywheel (12) with time when the engine is operated to the stop condition by the automatic start-stop module. In the graph, flywheel (12) speed is plotted on Y-axis, while elapsed time is represented on the X-axis. As illustrated, when the vehicle is stopped from idling speed, for example around 800 RPM, the flywheel (12) speed reaches a peak of about 830 rpm from 760 rpm for first few seconds [about 10 seconds] and drops back to about 760 rpm for next few seconds [about 10 seconds]. This pattern continues until elapsed time reaches about 35 seconds. Thereafter, there is a continuous rise and fall pattern with a steep downward trend until the 85th second, when the speed has dipped to about 40 rpm. Then, there is a sudden increase to 300 rpm at 90th second, and a gradual decrease upto 110th second when the flywheel (12) comes to rest. Hence, from the graph it is evident that, the apparatus (10) may utilize the energy from the flywheel to crank an engine of the vehicle without aid of starter motor.

In an exemplary embodiment, experimental investigations indicate that, the minimum angular rotation required to crank the engine may be 200 RPM. The apparatus (10) may impart an angular rotation at a speed of 200 RPM to the crankshaft upto 60 seconds from the time engine is operated from halt condition, even after considering the mechanical losses. Thus, the apparatus (10) may effectively crank an engine upto one minute, since the time engine is brought to stop condition. This reduces requirement of using the starter motor frequently for starting the engine, thus eliminating the need for batteries of higher capacity. The above presented data is for the purposes of understanding only and should not be construed as limitation to embodiments of the present disclosure.

It is to be understood that a person of ordinary skill in the art would develop an apparatus of any configuration without deviating from the scope of the present disclosure. Further, various modifications and variations may be made without departing from the scope of the present invention. Therefore, it is intended that the present disclosure covers such modifications and variations provided they come within the ambit of the appended claims and their equivalents.

Advantages:
The present disclosure provides an apparatus for staring an engine having an automatic start-stop module. The apparatus is configured to use energy available in the flywheel to crank and start the engine. This eliminates the use of starter motor to crank the engine during temporary start-stop condition, like city traffic.

The present disclosure provides an apparatus for staring an engine which minimizes the battery power consumption by the starter motor, since necessary cranking power may be supplied by the flywheel without use of starter motor during momentary engine start and stop.

The present disclosure provides an apparatus for staring an engine in which the flywheel is modified has a split design unlike the conventional single mass flywheels. This makes the flywheel of the present disclosure retro-fittable, wherein existing single body flywheels may be replaced with split flywheel of present disclosure to achieve momentary start-stop control without the need for starter motor.

The present disclosure provides an apparatus for staring an engine in which the flywheel may assist in damping out vibrations during transmission of power. The mechanism may be actuated to release the annular gear, whereby the rotating annular gear minimizes or ceases out amplitudes of vibration occurring due to crankshaft rotation or during engine cranking.

Equivalents
With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.

It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., "a" and/or "an" should typically be interpreted to mean "at least one" or "one or more"); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to "at least one of A, B, and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to "at least one of A, B, or C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B" will be understood to include the possibilities of "A" or "B" or "A and B."

While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

TABLE OF REFERRAL NUMERALS

Referral Numerals Description
10 Apparatus for starting an engine
12 Flywheel
14 Wheel
16 Crankshaft
20 Epicyclic gear train
22 Sun gear
22A Sun gear bearing
22B Provision in the sun gear
24 Annular gear
24A Annular gear bearing
24B Provision in the annular gear
26 Planet gears
26A Planet gear bearing
30 Mechanism
40 Control unit
50 Starter motor
A-A Crankshaft axis