Method for determining constraints on input torque in a hybrid transmission

• US 8,296,021 B2
• Filed: 10/21/2008
• Issued: 10/23/2012
• Est. Priority Date: 11/03/2007
• Status: Active Grant

• Current Assignee: Bayerische Motoren Werke AG, Daimler AG (Mercedes-Benz Group AG), Chrysler Group LLC (Stellantis NV)
• Original Assignee: Bayerische Motoren Werke AG, GM Global Technology Operations LLC (General Motors Company), Daimler AG (Mercedes-Benz Group AG), Chrysler Group LLC (Stellantis NV)
• Inventors: Heap, Anthony H., Hsieh, Tung-Ming
• Primary Examiner(s): Tarcza, Thomas
• Assistant Examiner(s): Murshed, Nagi
• Application Number:
  US12/254,961
• Publication Number:
  US 20090118942A1
• Time in Patent Office: 1,463 Days
• Field of Search: None
• US Class Current: 701/54
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 6/26 characterised by the motors or the generators
• 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 10/24 including control of energy storage means
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/15 Control strategies specially adapted for achieving a particular effect
• CPC Class Codes: B60W 2050/0005 Processor details or data handling, e.g. memory registers or chip architecture
• CPC Class Codes: B60W 2050/0022 Gains, weighting coefficients or weighting functions
• CPC Class Codes: B60W 2510/0657 Engine torque
• CPC Class Codes: B60W 2510/083 Torque
• CPC Class Codes: B60W 2510/244 Charge state
• 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: B60W 2710/105 : Output 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 3/728 : with means to change ratio in the mechanical gearing
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility

Abstract

A hybrid transmission includes torque machines and an energy storage device connected thereto. Thee hybrid transmission is operative to transfer power between an input member and an output member and the torque machines. A method for controlling the hybrid transmission includes monitoring operating parameters of the hybrid transmission, monitoring an operator demand for power, determining an output torque range to the output member based upon states of the operating parameters of the hybrid transmission, constraining the output torque range to the output member based upon the operator demand for power, and determining input torque constraints to the input member based upon the constrained output torque range to the output member.

Claims

1. Method for controlling a hybrid transmission including torque machines and an energy storage device connected thereto, the hybrid transmission operative to transfer power between an input member and an output member and the torque machines, wherein a control module performs the following steps comprising:

monitoring operating parameters of the hybrid transmission;

monitoring an operator demand for power;

determining an output torque range to the output member based upon states of the operating parameters of the hybrid transmission;

constraining the output torque range to the output member based upon the operator demand for power;

determining input torque constraints to the input member based upon the constrained output torque range to the output member; and

controlling operation of an engine coupled to the input member based upon the input torque constraints to the input member.

2. The method of claim 1, further comprising:

determining maximum and minimum power constraints for the energy storage device;

determining maximum and minimum motor torque outputs from the torque machines; and

determining the output torque range to the output member based upon the maximum and minimum power constraints for the energy storage device and the maximum and minimum motor torque outputs from the torque machines.

3. The method of claim 1, further comprising:

monitor operator inputs to an accelerator pedal and a brake pedal;

determining an immediate accelerator torque request and a net accelerator torque request based upon the operator inputs to the accelerator pedal and the brake pedal; and

constraining the output torque range to the output member based upon the immediate accelerator torque request and a net accelerator torque request.

4. The method of claim 1, further comprising:

formulating equations representing maximum and minimum motor torque constraints for the first and second torque machines and equations representing maximum and minimum power constraints for the energy storage device;

formulating a parametric equation representing the output torque;

formulating a parametric equation representing a range for a first torque constraint;

formulating a parametric equation representing a range for a second torque constraint;

transforming the equations representing the maximum and minimum power constraints for the energy storage device to equations comprising concentric circles having corresponding radii;

transforming the equations representing the maximum and minimum motor torque constraints for the first and second torque machines to equations comprising lines;

transforming the parametric equation representing the range for the first torque constraint;

transforming the parametric equation representing the range for the second torque constraint;

transforming the parametric equation representing the output torque; and

determining transformed minimum and maximum raw output torques based upon the transformed minimum and maximum motor torque constraints for the first and second torque machines, the transformed maximum and minimum power constraints for the energy storage device, the transformed range for the first torque constraint and the transformed range for the second torque constraint.

5. The method of claim 4, further comprising simultaneously solving the parametric equations for the transformed minimum and maximum motor torque constraints for the first and second torque machines, the transformed maximum and minimum power constraints for the energy storage device, the transformed range for the first torque constraint and the transformed range for the second torque constraint to determine the transformed minimum and maximum raw output torques.

6. The method of claim 4, further comprising retransforming the transformed minimum and maximum raw output torques to determine the minimum and maximum raw output torques from the transmission.

7. The method of claim 4, further comprising:

formulating a first parametric torque equation representing the input torque;

formulating a second parametric torque equation representing the minimum and maximum raw output torques;

formulating a third parametric torque equation representing a range for a second torque constraint;

transforming the first, second, and third parametric equations; and

determining transformed minimum and maximum raw input torques based upon the transformed minimum and maximum motor torque constraints for the first and second torque machines, the transformed maximum and minimum power constraints for the energy storage device, the transformed range for the minimum and maximum raw output torques and the transformed range for the second torque constraint.

8. The method of claim 7, further comprising

simultaneously solving the parametric equations for the transformed minimum and maximum motor torque constraints for the first and second torque machines, the transformed maximum and minimum power constraints for the energy storage device, the transformed range for the minimum and maximum raw output torques and the transformed range for the second torque constraint to determine the transformed minimum and maximum raw input torques.

9. The method of claim 7, further comprising retransforming the transformed minimum and maximum raw input torques to determine the minimum and maximum raw input torques.

10. A method for controlling a powertrain including an engine mechanically coupled to a transmission, the transmission operative in an operating range state to transfer power between the engine and first and second electric machines and an output member by selectively applying torque transfer clutches, the first and second electric machines electrically connected to an electrical energy storage device, wherein a control module performs the following steps comprising:

monitoring operating parameters of the hybrid transmission;

monitoring an operator demand for power;

determining an output torque range to the output member based upon states of the operating parameters of the hybrid transmission;

constraining the output torque range to the output member based upon the operator demand for power;

determining input torque constraints to the input member based upon the constrained range of output torque to the output member;

constraining engine torque based upon the input torque constraints to the input member and the operator demand for power; and

controlling operation of the engine based upon the constrained engine torque.

11. The method of claim 10, further comprising determining available battery power from the electrical energy storage device and determining maximum and minimum motor torques from the first and second electric machines, and determining the output torque range to the output member based thereon.

12. The method of claim 11, further comprising:

determining maximum and minimum power constraints for the electrical energy storage device;

determining maximum and minimum motor torques from the first and second electric machines; and

determining the output torque range to the output member based upon the maximum and minimum power constraints for the electrical energy storage device and the maximum and minimum motor torques from the first and second electric machines.

13. Method for controlling a hybrid transmission including first and second torque machines and an energy storage device connected thereto, the hybrid transmission operative to transfer power between an input member and an output member and the first and second torque machines, wherein a control module performs the following steps comprising:

monitoring operating parameters of the hybrid transmission;

monitoring an operator demand for power;

determining an output torque range to the output member based upon states of the operating parameters of the hybrid transmission;

constraining the output torque range to the output member based upon the operator demand for power; and

determining input torque constraints to the input member based upon the constrained range of output torque to the output member.