# US 7,610,976 B2 · Hybrid powertrain with electrically variable transmission having parallel friction launch and method

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- Number: US 7,610,976 B2
- Document ID: US7610976B2
- Status: Granted
- Kind: B2
- Application number: 11/416,912
- Filed: 2006-05-03
- Published: 2007-11-08
- Granted: 2009-11-03
- Earliest claimed: 2006-05-03
- Assignees: GM Global Technology Operations LLC
- Inventors: Alan G. Holmes; Michael R. Schmidt; Donald Klemen; Larry T. Nitz; Grantland I. Kingman; Anthony H. Heap; Gregory A. Hubbard; Brendan M. Conlon
- Web page: https://patentgrep.com/patent/US7610976B2

## CPC

- B60W 20/00: Control systems specially adapted for hybrid vehicles {(hybrid vehicle design, B60K6/00; electric vehicles B60L)}
- B60K 6/445: Differential gearing distribution type
- B60K 6/448: Electrical distribution type
- B60W 10/02: including control of driveline clutches
- B60W 10/06: including control of combustion engines
- B60W 10/08: including control of electric propulsion units, e.g. motors or generators
- B60W 10/115: with planetary gears
- B60W 10/26: for electrical energy, e.g. batteries or capacitors
- B60W 30/18027: {Drive off, accelerating from standstill}
- B60W 2510/0657: Engine torque
- B60W 2710/0666: Engine torque
- F16H 2037/0866: {Power-split transmissions with distributing differentials, with the output of the CVT connected or connectable to the output shaft}
- F16H 2037/102: {the input or output shaft of the transmission is connected or connectable to two or more differentials}
- F16H 2037/104: {Power-split transmissions with at least one end of a CVT connected or connectable to two or more differentials}
- F16H 2037/106: {with switching means to provide two variator modes or ranges}
- Y02T 10/62: Hybrid vehicles
- B60W: CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60K: ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
- F16H: GEARING
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A hybrid powertrain includes a control unit that regulates electric power interchange an energy storage device and a motor/generator for causing selective torque generation by the motor/generator and for controlling engagement of torque-transmitting mechanisms. The control unit is configured to place the torque-transmitting mechanism in slipping engagement to launch the vehicle and thereby decouple a fixed relationship between engine torque and motor/generator torque or between engine torque and torque at the output member. A method of operating a hybrid vehicle powertrain is also provided.

## Claims

### Claim 1

A method of operating a hybrid vehicle powertrain having an engine, an input member operatively connectable with the engine, a motor/generator, an electric power storage device for interchanging electrical power with said motor/generator, a differential gear set operatively connected between the input member and the output member and having a first, a second and a third member, power flow from the engine and the motor/generator respectively to said output member being through different members of said differential gear set such that the transmission is an electrically variable transmission, comprising:
slipping at least one torque-transmitting mechanism via a control unit operable to control engagement of said at least one torque-transmitting mechanism; wherein non-slipping engagement of said at least one torque-transmitting mechanism at least partially establishes a fixed speed ratio between said input member and said output member; wherein any other torque-transmitting mechanisms necessary to establish the fixed speed ratio are engaged; wherein said at least one torque-transmitting mechanism is selected from the group consisting of:
a torque-transmitting mechanism that connects the input member with the differential gear set;
a torque-transmitting mechanism that connects one of the members of the differential gear set with a stationary member where another of the members of the differential gear set is connected with the output member; and
a torque-transmitting mechanism that connects any two members of the differential gear set together for common rotation;
said slipping thereby decoupling a fixed relationship between engine torque and motor/generator torque or between engine torque and torque at said output member established by the differential gear set; and
controlling the speed of the engine and the speed of the motor/generator to launch the vehicle.

### Claim 2 (depends on 1)

The method of claim 1, wherein said controlling is characterized by maximizing torque of the engine and by maximizing torque of the motor/generator given available electric power storage device power.

### Claim 3 (depends on 1)

The method of claim 1, wherein said controlling is characterized by controlling the speed of the engine and the speed of the motor/generator independently of one another.

### Claim 4 (depends on 1)

The method of claim 1, wherein the motor/generator is a first motor/generator and the hybrid vehicle powertrain has a second motor/generator; wherein the electric power storage device is operable for interchanging electrical power with the second motor/generator; wherein the control unit is operable for regulating electrical power interchange between the electric power storage device and the second motor/generator for causing selective torque generation by the second motor/generator; wherein said slipping places one of the motor/generators in slipping relationship with said output member; wherein the other of said motor/generators is in non-slipping relationship with said output member; wherein each of said motor/generators is characterized by a respective predetermined torque capacity; wherein said electric power storage device is characterized by a predetermined maximum power limit;
wherein said controlling includes causing electric power flow to said motor/generator in non-slipping relationship with the output member, and causing electric power flow to the motor/generator in slipping relationship with the output member only after the motor/generator in slipping relationship is operating at a predetermined state characterized by said predetermined torque capacity or said electric power storage device is providing power at said predetermined maximum power limit.

### Claim 5 (depends on 1)

The method of claim 1, wherein said slipping is of two of said torque-transmitting mechanisms to thereby distribute a heat load generated during launch.

### Claim 6

A method of operating a hybrid vehicle powertrain having an engine, an input member operatively connectable with the engine, a first and a second motor/generator, an electric power storage device for interchanging electrical power with said motor/generators, a differential gear set operatively connected between the input member and the output member and having a first, a second and a third member, power flow from the engine and one of the motor/generators respectively to said output member being through different members of said differential gear set such that the transmission is an electrically variable transmission:
slipping a torque-transmitting mechanism via a control unit operable to control engagement of the torque-transmitting mechanism, wherein the torque-transmitting mechanism connects any two members of the differential gear set together for common rotation; said slipping thereby decoupling a fixed relationship between engine torque and torque of the motor/generator connected with one of the members of the differential gear set as established by the differential gear set; and
controlling the speed of the engine and the speed of the motor/generator connected with one of the members of the differential gear set independently of one another to launch the vehicle.

### Claim 7 (depends on 6)

The method of claim 6, wherein said slipping causes one of the motor/generators to be in slipping relationship with respect to the output member and the other of the motor/generators to be in non-slipping relationship with the output member; wherein said motor/generator in non-slipping relationship with the output member is characterized by a predetermined torque capacity; wherein said electric power storage device is characterized by a predetermined maximum power limit;
wherein said controlling includes causing electric power flow to said motor/generator in non-slipping relationship with the output member, and causing electric power flow to the motor/generator in slipping relationship with the output member only after the motor/generator in slipping relationship is operating at said predetermined torque capacity or said electric power storage device is providing power at said maximum power limit.