METHOD AND CONTROL ARCHITECTURE TO DETERMINE MOTOR TORQUE SPLIT IN FIXED GEAR OPERATION FOR A HYBRID POWERTRAIN SYSTEM

• US 20090115349A1
• Filed: 10/13/2008
• Published: 05/07/2009
• Est. Priority Date: 11/07/2007
• Status: Active Grant

• Current Assignee: Bayerische Motoren Werke AG, Daimler AG (Mercedes-Benz Group AG), Chrysler Group LLC (Stellantis NV)
• Original Assignee: BMW AG (Bayerische Motoren Werke AG), GM Global Technology Operations Incorporated (General Motors Company), Daimler AG (Mercedes-Benz Group AG), Chrysler LLC (Stellantis NV)
• Inventors: Heap, Anthony H.
• Granted Patent: US 8,209,097 B2
• Time in Patent Office: Days
• US Class Current: 701/22
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 6/365 with the gears having orbital motion
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60K 6/547 the transmission being a stepped gearing
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/443 Torque
• CPC Class Codes: B60L 2240/486 Operating parameters
• CPC Class Codes: B60W 10/02 including control of driveline clutches
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/115 with planetary gears
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 20/11 using model predictive control [MPC] strategies, i.e. control methods based on models predicting performance utilising navigation and traffic information in the control strategy B60W20/12
• CPC Class Codes: B60W 2050/0006 Digital architecture hierarchy
• CPC Class Codes: B60W 2050/0009 Proportional differential [PD] controller
• CPC Class Codes: B60W 2050/0031 Mathematical model of the vehicle
• CPC Class Codes: B60W 2510/0275 Clutch torque
• CPC Class Codes: B60W 2510/0657 Engine torque
• CPC Class Codes: B60W 2510/083 Torque
• CPC Class Codes: B60W 2510/1005 Transmission ratio engaged
• CPC Class Codes: B60W 2510/1025 : Input torque
• CPC Class Codes: B60W 2510/244 : Charge state
• CPC Class Codes: B60W 2510/246 : Temperature
• CPC Class Codes: B60W 2540/10 : Accelerator pedal position
• CPC Class Codes: B60W 2540/12 : Brake pedal position
• CPC Class Codes: B60W 2710/083 : Torque
• CPC Class Codes: F16H 2037/0866 : Power split variators with distributing differentials, with the output of the CVT connected or connectable to the output shaft
• CPC Class Codes: F16H 2037/102 : the input or output shaft of the transmission is connected or connectable to two or more differentials
• CPC Class Codes: F16H 2037/104 : Power split variators with one end of the CVT connected or connectable to two or more differentials
• CPC Class Codes: F16H 2037/106 : with switching means to provide two variator modes or ranges
• CPC Class Codes: F16H 2200/201 : with three sets of orbital gears
• CPC Class Codes: F16H 2200/2041 : with four engaging means
• CPC Class Codes: F16H 3/728 : with means to change ratio in the mechanical gearing
• CPC Class Codes: Y02T 10/40 : Engine management systems
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/84 : Data processing systems or methods, management, administration

Abstract

An electro-mechanical transmission is operative to transmit mechanical torque originating from an engine and first and second electric machines to an output member. The electric machines are electrically-operatively connected to an energy storage system for electrical power flow therebetween. A Method for operating the electro-mechanical transmission includes operating the electro-mechanical transmission in a fixed gear operating range state, determining a minimum power flow between the energy storage system and the first and second electric machines to meet an operator torque request based upon electrical power constraints and motor torque constraints, commanding a motor torque from the first electric machine based upon the minimum power flow, and commanding a motor torque from the second electric machine based upon the minimum power flow, a torque input from the engine and the commanded motor torque from the first electric machine to meet the operator torque request in the fixed gear operating range state.

Claims

1. Method for operating an electro-mechanical transmission operative to transmit mechanical torque originating from an engine and first and second electric machines to an output member, the electric machines electrically-operatively connected to an energy storage system for electrical power flow therebetween, the method comprising:

operating the electro-mechanical transmission in a fixed gear operating range state;

determining a minimum power flow between the energy storage system and the first and second electric machines to meet an operator torque request based upon electrical power constraints and motor torque constraints;

commanding a motor torque from the first electric machine based upon the minimum power flow; and

commanding a motor torque from the second electric machine based upon the minimum power flow, a torque input from the engine and the commanded motor torque from the first electric machine to meet the operator torque request in the fixed gear operating range state.

2. The method of claim 1, further comprising:

determining the motor torque output from the first electric machine based upon the electrical power constraints of the energy storage device and a motor torque output from the second electric machine that minimizes electric power flow between the energy storage system and the first electric machine.

3. The method of claim 2, further comprising determining the motor torque output from the first electric machine to meet the operator torque request based upon the electrical power constraints and motor torque constraints.

4. The method of claim 3, wherein determining the electrical power constraints of the energy storage device comprises determining maximum and minimum electrical power outputs from the energy storage device based upon a battery state of charge, a battery temperature, and an electric current throughput.

5. The method of claim 1, further comprising determining minimum power flows between the energy storage system and the first and second electric machines to meet the operator torque request based upon the electrical power constraints and the motor torque constraints and based upon the torque input from the engine.

6. The method of claim 1, wherein determining the minimum power flow between the energy storage system and the first and second electric machines comprises:

developing a mathematical formula representative of the output torque based upon clutch reaction torques, transmission speed ratios, and the motor torques from the first and second electric machines and the torque input from engine; and

executing a partial derivative of the mathematical formula based upon the motor torque output from the first electric machine.

7. The method of claim 6, comprising determining a relationship between the motor torque from the first electric machine and the motor torque from the second electric machine based upon the partial derivative of the mathematical formula.

8. The method of claim 6, further comprising linearly transforming the mathematical formula representative of the output torque to a second operating space.

9. The method of claim 8, further comprising defining a calibration array to determine the motor torques from the first and second electric machines.

10. The method of claim 1, further comprising:

determining the electrical power constraints of the energy storage device;

determining a range of motor torques from the first electric machine to meet the operator torque request based upon the electrical power constraints of the energy storage device;

determining a range of motor torques from the second electric machine to meet the operator torque request based upon the electrical power constraints of the energy storage device;

identifying a minimum motor torque from the first electric machine within the electrical power constraints of the energy storage device and within the range of motor torques from the first electric machine; and

identifying a motor torque from the second electric machine to meet the operator torque request based upon the electrical power constraints of the energy storage device and the identified minimum motor torque from the first electric machine and within the range of motor torques from the second electric machine.

11. The method of claim 1, further comprising selectively applying torque-transmitting clutches to operate the electro-mechanical transmission in the fixed gear operating range state.

12. Method for operating a powertrain including an internal combustion engine, first and second electric machines, and an electro-mechanical transmission mechanically-operatively coupled to transmit torque to an output member to meet an operator torque request, the first and second electric machines electrically-operatively connected to an energy storage system for electrical power flow therebetween, the method comprising:

operating the electro-mechanical transmission in a fixed gear operating range state;

determining optimal electrical power flow between the energy storage system and the first and second electric machines based upon maximum and minimum electrical power potentials of the energy storage system and output torque constraints of the first and second electric machines;

commanding a motor torque from the first electric machine based upon the optimal electrical power flow between the energy storage system and the first and second electric machines; and

commanding a motor torque from the second electric machine based upon a torque input from the engine and the commanded motor torque from the first electric machine to meet the operator torque request.

13. The method of claim 12, wherein the optimal electrical power flow between the energy storage system and the first electric machine is determined based upon the maximum and minimum electrical power potentials from the energy storage device and the commanded motor torque from the second electric machine.

14. The method of claim 13, further comprising:

determining the maximum and minimum electrical power potentials of the energy storage device;

determining a range of motor torques from the first electric machine to meet the operator torque request based upon the maximum and minimum electrical power potentials of the energy storage device; and

identifying a preferred torque output from the first electric machine corresponding to the minimum electrical power potential of the energy storage device and the commanded motor torque from the second electric machine.

15. The method of claim 14, further comprising:

determining a range of motor torques from the second electric machine to meet the operator torque request based upon constraints of the energy storage device;

identifying a motor torque from the first electric machine corresponding to the minimum power within the constraints of the energy storage device and within the range of motor torques from the first electric machine; and

identifying a motor torque from the second electric machine to meet the operator torque request based upon constraints of the energy storage device and the identified motor torque from the first electric machine corresponding to the minimum power and within the range of motor torques from the second electric machine.

16. Method for determining an output from an electric machine operative to transmit torque to an electro-mechanical transmission, comprising:

operating the electro-mechanical transmission in a fixed gear operating range state and monitoring an operator torque request;

determining an input from an engine operative to transmit power to the electro-mechanical transmission;

determining electrical power constraints of an energy storage device operative to transmit power to the electric machine to meet the operator torque request;

determining a range of motor torques from the electric machine to meet the operator torque request based upon the power constraints of the energy storage device;

optimizing power output from the energy storage device; and

determining a torque output from the electric machine corresponding to the optimized power output from the energy storage device.

17. The method of claim 16, further comprising optimizing the power output from the energy storage device based upon the electrical power constraints from the energy storage device and a motor torque from a second electric machine operative to transmit torque to the electro-mechanical transmission to meet the operator torque request.

18. The method of claim 17, wherein the electric power constraints of the energy storage device are based upon a battery state of charge, a battery temperature, and an electric current throughput.