FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
PROVISIONAL SPECIFICATION (See Section 10; rule 13)


TITLE OF THE INVENTION Drive System for a vehicle
APPLICANTS
TATA MOTORS LIMITED, an Indian company
having its registered office at Bombay House,
24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
INVENTOR
Mr. V Janardhanan an Indian national of
TATA MOTORS LIMITED, an Indian company
having its registered office at Bombay House,
24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India

PREAMBLE TO THE DESCRIPTION The following specification describes the invention.

FIELD OF THE INVENTION
The invention concerns an automated manual transmission with an integral starter-generator, launch, creep & synchronizing device for a vehicle.
BACKGROUND OF THE INVENTION
Drive systems for vehicles customarily comprise an internal combustion motor as the driving machine, a subsequent transmission and a friction clutch placed between the internal combustion motor and the transmission or again, comprise a hydrodynamic converter placed between the internal combustion motor and the transmission. The friction clutch or the converter are burdened with losses and present energy losses in the drive train.
OBJECTS OF THE INVENTION
One of the targets for the invention is avoiding these losses and providing a smooth launch & infinitely variable creep. The invention also targets complete range of creep & launch functions without any dependency on battery if need be, integrated starter-generator functions, operating the engine in its fuel efficient region, gear synchronization function, engine-transmission speed matching & regenerative braking function.
SUMMARY OF THE INVENTION
In accord with the invention, it is proposed to place a power management device which is essentially a epicyclic gear drive between a driving machine and a transmission, which said epicyclic gear drive encompasses the three elements, sun gear, internal gear, and planet carrier. Of these three elements, the internal gear is

connected to the transmission, the planet carrier is bound to the driving machine, and sun gear is coupled with the electromotive unit. The power management device is of two types - a power sum device and a power split device. The elctromotive unit can behave as a generator or a motor that is, it is of four quadrant type. A clutch is introduced between the sun & the carrier for the lockup or bypass of the epicyclic drive. In an additional embodiment a one way clutch is provided in the transmission input driveline to prevent anticlockwise rotation of the input shaft. In an additional arrangement, a one way clutch is provided on the engine crank shaft to prevent anticlockwise rotation of the crank shaft for start-stop operation or for the Zero-Emission-Vehicle-operation, that is, powering the vehicle by the electric motor, when the internal combustion engine is not turning. In another embodiment, an additional electric motor in combination acts upon transmission, providing for additional torque during acceleration demands as well as providing for powershifting. In yet another embodiment a splitter unit is added with use of common internal gear between the power management device and the splitter unit. In another embodiment a speed reducing device is provided for the electromotive device.
The power management epicyclic configuration of the power split type allows for a pure generative mode of the electromotive unit during launch, thereby eliminating dependency of battery. This configuration also allows for efficient operation of the engine
Modern diesel engines produce peak torques at a low speed, permitting large epicyclic ratios yet running the generator within its speed limits during start of launch. The torque diverted during launch to the generator in the power split device is compensated by minor deepening of the low gear. Vehicles which have a higher degree of electrification of its equipment, this low gear deepening may be avoided. For engines that produce peak torques at a higher speed, the epicyclic ratio is made shallower along with higher compensatory deepening of low gear or the generator is provided with a speed reducer unit to keep the generator speeds

under check during start of launch. With these kind of engines when a shallower epicyclic ratio along with compensatory deepening of low gear or provision of speed reducer is not feasible, the embodiment with additional motor at the transmission end is advisable. The add on / support motor of this embodiment supports with additional torque during launch & as well aids in power uninterrupted gear shifting, by driving the vehicle momentarily during gear shift operation. The add on motor also acts as a generator for regenerative braking. By means of the invented drive system, a more environmentally friendly functioning of the vehicle and a lowering of costs are attained. With the present invention, a drive system is presented, which avoids any friction based starting element. What otherwise would be power lost in slippage, can be now used as additional power for the electrical on-board system. At the same time, use of the electric motor permits an increase of torque and the motor can be employed as a booster element in the concept of additional drive, during an accelerating period.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described, by way of example, with reference to the
accompanying drawings in which:
FIG. 1 is a sketch of the principles of the invention;
FIG. 2 is an additional sketch describing some of the interactions of the
transmission control unit with various controllers and sensors.
FIG. 3 is an embodiment in accord with FIG. 1 with a one way clutch between the
transmission input shaft & the transmission housing.
FIG. 4 is an embodiment in accord with FIG. 1 with an electromotive device
connected to the transmission output shaft.
FIG. 5 is an embodiment in accord with FIG. 1 with an additional overrunning
clutch between the engine output shaft & the engine housing.
FIG. 6 is an embodiment in accord with FIG. 1 with a splitter unit.

FIG. 7 is an embodiment in accord with FIG. 1 with an epicyclic speed reducer for the electromotive device.
FIG. 8 is an embodiment in accord with FIG. 1 with the power management device being a power sum up epicyclic arrangement.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 presents a sketch of the principles of the invented system. The system consists of a motive drive source 1, a power management epicyclic system 3, generator /motor 4 and a transmission 2. The generator/motor can operate in a four quadrant mode. At the crank shaft 5 of a drive source 1 , a torsional vibration damper 6 is installed, which is connected with the planet carrier 8 of epicyclic system 3 through a planet carrier shaft 7. The power management epicyclic system 3 is in power split configuration. The power management epicyclic system 3 in power split configuration consists of the planet carrier 8 , the internal gear 11 , the planet gears 9 & the sun gear 10 .The planet carrier 8 carries at least three planet gears 9. The planet gears 9 mesh with both the sun gear 10 & the internal gear 11. The sun gear 10 is connected with the hollow shaft 12 which is connected to a clutch 13. The clutch 13 establishes a rigid connection between the planet carrier 8 & the sun gear 10 when it is required to bypass the epicyclic system 3. An electromotive unit 4 is connected to the sun gear 10. The electromotive unit 4 can behave as a generator or a motor. The internal gear 11 is connected to the transmission input shaft 14. The transmission 2 in the figures 1, 3, 4,5,6,1 &H is a representative only. The transmission 2 has an output shaft 15. The transmission output shaft 15 drives the wheels. The said transmission 2 can be a transaxle also. The drive source 1 drives the torsional vibration damper 6 which in turn drives the planet carrier shaft 7. The planet carrier shaft 7 drives the planet carrier 8 which in turn drives the sun gear 10 and the internal gear 11 through the planet gears 9. The

sun gear 10 drives the motor / generator 4. The internal gear 11 drives the transmission input shaft 14. The transmission output shaft 15 drives the wheels.
FIG. 2 shows the transmission control unit 32 which sends & receives information & instructions from the engine control unit 33, & brake control unit 34. The transmission control unit 32 receives speed information from engine speed sensor 35, transmission input shaft speed sensor 36 & transmission output shaft speed sensor 37.
FIG 3 shows the arrangement in accord with FIG. 1, but with a one way clutch 16 connecting the transmission input shaft 14 & the transmission housing 17(rigidly held). The one way clutch 16 prevents the transmission input shaft 14 from rotating in a direction opposite to that of the rotation of the engine 1. The one way clutch 16 can also be a friction clutch.
FIG. 4 shows the arrangement in accord with FIG. 1 , but with the support motor/generator 18 connected to the transmission output shaft 15. The support motor / generator 18 drives the transmission output shaft 15 during the gear shift operation, supports with additional torque during vehicle acceleration, launch & supports vehicle braking. Corresponding components are designated by the same reference numbers as in FIG. 1.
FIG. 5 shows the arrangement in accord with FIG. 1 . but with an additional one way clutch 19 which connects the crank shaft 5 & the engine housing 20. Corresponding components are designated by the same reference numbers as in FIG. 1. The one way clutch 19 serves for the drive of the vehicle powered by the electric motor 4 , without the necessity that the engine rotates. The one way clutch 19 can also be a friction clutch.

FIG. 6 presents the arrangement of FIG. 1 , but with an add on splitter unit 21. The splitter unit 21 consists of planet gears 22, planet carrier 23, sun gear 24, hollow shaft 25 & dog clutch 26. The internal gear 11 of epicyclic system 3 meshes with the planet gears 22, which are carried by the planet carrier 23. The planet gears 22 also mesh with the sun gear 24. The sun gear 24 is connected to the hollow shaft 25. The dog clutch 26 on the hollow shaft 25 connects the sun gear 24 with either the planet carrier 23 or the transmission housing 17. The internal gear 11 of the epicyclic system 3 drives the planet gears 22 of the splitter unit 21. The planet gears 22 drive the planet carrier 23 and the sun gear 24. The dog clutch 26 can engage the sun gear 24 with the planet carrier 23 or the transmission housing 17, and by doing so can provide for a high gear or a low gear. Corresponding components are designated by the same reference numbers as found in FIG. 1.
FIG. 7 presents the arrangement of FIG. 1 , but with a speed reducer unit for the electromotive unit. The speed reducer unit 27 consists of sun gear 28, planet gears 29, planet carrier 30, & internal gear 31. The sun gear 28 is connected to the hollow shaft 12 of sun gear 10. The sun gear 28 meshes with the planet gears 29 which are carried by the planet carrier 30. The planet gears 29 also mesh with the internal gear 31. The planet carrier 30 is connected to the electromotive unit 4. The internal gear 31 is rigidly held. The clutch 13 establishes a rigid connection between the planet carrier 8 & the sun gear 10 when it is required to bypass the epicyclic system 3. The sun gear 10 drives the sun gear 28, which in turn drives the planet gears 29. The planet gears 29 drive the planet carrier 30 which in turn drives the motor / generator 4. Corresponding components are designated by the same reference numbers as found in FIG. 1.
FIG 8 shows the arrangement in accord with FIG. 1, but the power management device 3 being in a power sum up configuration of the, epicyclic. The planet

carrier 8 carries planet gears 9 & 9A. The planet gear 9 meshes with the sun gear 10 and planet gear 9A. The planet gear 9A meshes with the internal gear 11. Corresponding components are designated by the same reference numbers as found in FIG. 1.
The drive source 1 drives the torsional vibration damper 6 which in turn drives the planet carrier shaft 7. The planet carrier shaft 7 drives the planet carrier 8 which in turn drives the sun gear 10 and the internal gear 11 through the planet gears 9 & 9A. The sun gear 10 drives the motor / generator 4. Here it is also possible that the motor 4 will drive the sun gear 10 to provide additional power to the transmission. The internal gear 11 drives the transmission input shaft 14. The transmission output shaft 15 drives the wheels.
Functioning of the system explained below with reference to figures 1 -8
ENGINE START:
To start the engine 1 in neutral, the transmission control unit 32 instructs the the
clutch 13 to open and instructs the transmission 2 to shift to neutral gear, then
instructs the clutch 13 to close, and instructs the electromotive unit 4 to start the
engine 1.
If there is a provision of a one way clutch 16 in accordance to FIG.3, then the
transmission control unit 32 instructs the clutch 13 to open, and then instructs the
electromotive unit 4 to start the engine 1.
To start the engine 1 in gear and when the vehicle is stationary, the transmission
control unit 32 instructs the clutch 13 to open and instructs the brake control unit
34 to apply the vehicle driving wheel brakes and then instructs the electromotive
unit 4 to start the engine 1.
If there is a provision of a one way clutch 16 in accordance to FIG.3, then the
transmission control unit 32 instructs the clutch 13 to open, and then instructs the
electromotive unit 4 to start the engine 1.

To start the engine 1 in gear and when the vehicle is moving, the transmission control unit 32 instructs the clutch 13 to open, instructs the electromotive unit 4 to start the engine 1.
GEAR SHIFTING:
To shift the gears in the transmission 2, the transmission control unit 32 instructs the clutch 13 to open, and then instructs the transmission 2 to disengage the current gear. The transmission control unit 32 gathers the speed information from the speed sensor 36 of transmission input shaft 14, speed sensor 37 of transmission output shaft 15, speed sensor 35 of engine 1, and then calculates the speed at which the engine 1 and the electromotive unit 4 should rotate to synchronize the next gear to be engaged. Based on the calculated speed, the transmission control unit 32 instructs the electromotive unit 4 and the engine 1 through the engine control unit 34 to change their respective speeds so that the transmission input shaft 14 rotates at the speed desired by the transmission control unit 32. Once this synchronization is done, the transmission control unit 32 instructs the transmission 2 to engage the synchronized gear.
During upshifting operation, after the current gear is disengaged, the transmission control unit 32 has the option of closing the clutch 13 and instructs the generator 4 to load the engine 1 to reduce its speed so that the transmission input shaft 14 rotates at the speed desired for synchronization.
To close the clutch 13 during the end of gear shifting operation, the transmission control unit 32 controls the speed of the electromotive unit 4 and the engine 1 to match the speed of the engine 1 and the transmission input shaft 14. After this speed matching operation the transmission control unit 4 instructs the clutch 13 to close.

VEHICLE LAUNCH :
To launch the vehicle, the transmission control unit 32 instructs the clutch 13 to open, then instructs the transmission 2 to engage the low gear, and then instructs the electromotive unit 4 to load the sun gear 10 so that the vehicle starts moving. The transmission control unit 4 monitors the speeds of transmission input shaft 14 and the speeds of the engine 1. Once the speed of transmission input shaft 14 matches with the speed of the engine 1, the transmission control unit 32 instructs the clutch 13 to close. The transmission control unit 4 monitors and controls the speed of the engine 1 so that the speed of the electromotive unit 4 is within its designed speed limit.
OPERATING THE ENGINE IN THE FUEL EFFICIENT RANGE:
To operate the engine 1 in its fuel efficient region while the vehicle is running, the transmission control unit 32 instructs the electromotive unit 4 to vary its generative load, till the engine 1 reaches the best possible operating point. In an another possibility to operate the engine in its fuel efficient region while the vehicle is running, the transmission control unit 32 instructs the clutch 13 to open and then instructs the electromotive unit 4 and the engine 1 to vary their speeds, till the engine 1 reaches the best possible operating point for fuel economy. The transmission control unit 32 decides to operate with either of the above possibilities, which ever gives a better fuel efficient operating point of the engine 1.
VEHICLE ON PURE ELECTRIC MODE:
To run the vehicle in a pure electric driven mode, the scheme in accordance to FIG 5 applies, and the transmission control unit 32 instructs the electromotive unit 4 to run as motor to drive the vehicle.

VEHICLE BRAKING & ACCELERATION SUPPORT:
To support the vehicle braking and to save the energy produced while braking the
vehicle the transmission control unit 32 instructs the electromotive unit 4 provide
a braking generative load on the sun gear 10.
To support the vehicle for acceleration in a higher gear the transmission control
unit 32 instructs the electromotive unit 4 to drive the sun gear 10.
When the vehicle requires additional power for launch and acceleration of the
vehicle, the transmission control unit 32 instructs the support motor / generator 18
as described in FIG.4 to drive the transmission output shaft 15.
To support the vehicle braking and to save the energy produced while braking the
vehicle the transmission control unit 32 instructs the support motor / generator 18
as described in FIG.4 to apply braking generative load on the transmission output
shaft 15.
POWER SHIFTING:
To provide uninterrupted power to the vehicle during the gear shift operation the transmission control unit 32 instructs the support motor / generator 18 as described in FIG.4 to drive the transmission output shaft 15.
SPLITTER UNIT:
The splitter unit 21 in accordance with FIG. 6 helps in dividing the transmission ratio steps and help the engine operate at a fuel efficient point. To engage the high mode of the splitter unit 21, the transmission control unit 32 controls the speed of the electromotive unit 4 to synchronize the splitter unit 21 for the speed of the high mode. Once the synchronization is done the transmission control unit 32 instructs the dog clutch 26 to engage with the planet carrier 23. To engage the low mode of the splitter unit 21. the transmission control unit 32 controls the speed of the electromotive unit 4 to synchronize the splitter unit 21 for the speed of the low

mode. Once the synchronization is done the transmission control unit 32 instructs the dog clutch 26 to engage with the transmission housing 17.
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Dated this 25th day of February 2009