Control architecture and method to evaluate engine off operation of a hybrid powertrain system operating in a continuously variable mode

• US 7,991,519 B2
• Filed: 05/14/2007
• Issued: 08/02/2011
• Est. Priority Date: 05/14/2007
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Snyder, Bryan R.
• Primary Examiner(s): Tran; Khoi
• Assistant Examiner(s): MOYER, DALE S
• Application Number:
  US11/748,156
• Publication Number:
  US 20080287255A1
• Time in Patent Office: 1,541 Days
• Field of Search: 701/22, 701/36, 701/48, 701/51, 701 53- 56, 701/60, 701/67, 701/69, 701/99, 701/110, 701/123
• US Class Current: 701/22
• 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: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/441 Speed
• 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 10/10 including control of change-speed gearings
• 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 20/30 Control strategies involving selection of transmission gear ratio control of change speed gearings, together with other vehicle sub-units B60W10/10; HEV transmission gearing B60K6/36; gearings and control thereof F16H
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2510/0657 Engine torque
• CPC Class Codes: B60W 2510/081 Speed
• CPC Class Codes: B60W 2510/083 Torque
• CPC Class Codes: B60W 2510/1025 : Input torque
• CPC Class Codes: B60W 2540/10 : Accelerator pedal position
• CPC Class Codes: B60W 2540/16 : Ratio selector position
• CPC Class Codes: B60W 2710/083 : Torque
• CPC Class Codes: B60W 2710/105 : Output torque
• CPC Class Codes: B60W 30/18027 : Drive off, accelerating from standstill
• CPC Class Codes: B60W 30/1882 : characterised by the working point of the engine, e.g. by using engine output chart
• 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 10/40 : 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

There is provided a method and apparatus to determine operating conditions for a powertrain comprising an internal combustion engine and first and second electrical machines and an electro-mechanical transmission selectively operative to transmit torque therebetween. The method comprises determining a torque output and an operating cost for operating the first and second electrical machines of the hybrid transmission effective to meet an operator torque request when the engine is operating in an engine-off operating state. Determining the torque output for operating the first and second electrical machines comprises executing a predetermined system equation effective to determine motor torque outputs from each of the first and second electrical machines based upon the selected parametric value for the input torque and the operator torque request.

Claims

1. Method for operating a powertrain comprising an internal combustion engine and first and second electrical machines and an electro-mechanical transmission configured to transmit torque therebetween, the method comprising

monitoring an operator torque request and a present transmission output speed;

calculating a first set of motor torques output from the first and second electrical machines corresponding to operating the electromechanical transmission in a first continuously variable mode with the engine in an engine-off operating state in response to the operator torque request and the present transmission output speed;

calculating a second set of motor torques output from the first and second electrical machines corresponding to operating the electromechanical transmission in a second continuously variable mode with the engine in the engine-off operating state in response to the operator torque request and the present transmission output speed;

calculating a first operating cost associated with the first set of motor torques output from the first and second electrical machines;

calculating a second operating cost associated with the second set of motor torques output from the first and second electrical machines;

selecting one of the first and second continuously variable modes as a preferred operating mode based upon the first and second operating costs; and

controlling the powertrain in the preferred operating mode with the engine in the engine-off operating state in response to the operator torque request and the present transmission output speed.

2. The method of claim 1, wherein calculating the first set of motor torques output from the first and second electrical machines corresponding to operating the electromechanical transmission in the first continuously variable mode with the engine in the engine-off operating state in response to the operator torque request and the present transmission output speed comprises executing a predetermined system equation to determine motor torque outputs from each of the first and second electrical machines based upon the operator torque request.

3. The method of claim 1, wherein the engine-off operating state comprises an engine crankshaft speed being zero revolutions per minute.

4. Apparatus, comprising:

a distributed control module architecture comprising;

a plurality of control modules adapted to control operation of a hybrid powertrain;

the hybrid powertrain comprising an internal combustion engine and first and second electrical machines and an electro-mechanical transmission configured to transmit torque therebetween;

the transmission selectively operative in one of first and second continuously variable operating modes through selective actuation of a plurality of torque-transfer clutches; and

,

the control modules configured to execute machine code stored therein, the machine code comprising;

code to monitor an operator torque request, a present transmission output speed and available battery power;

identify at least one permissible powertrain operating range state comprising an engine-off state;

determine torque outputs from the first and second electrical machines to achieve a powertrain torque output to meet the operator torque request when the powertrain is operating in the permissible powertrain operating range state comprising the engine-off state;

determine an operating cost for operating the first and second electrical machines to achieve the powertrain torque output to meet the operator torque request in the permissible powertrain operating range state comprising the engine-off state, the operating cost associated with the present transmission output speed and the available battery power;

select the permissible powertrain operating range state comprising the engine-off state based upon the operating costs; and

control the powertrain in the permissible powertrain operating range state comprising the engine-off state to meet the operator torque request.

5. The apparatus of claim 4, wherein the electro-mechanical transmission comprises a two-mode, compound split transmission selectively operative in one of the first and second continuously variable operating modes through selective actuation of one of the torque-transfer clutches.

6. The apparatus of claim 5, further comprising the electro-mechanical transmission operative in the first continuously variable operating mode through selective actuation of a first one of the torque-transfer clutches.

7. The apparatus of claim 5, further comprising the electro-mechanical transmission operative in the second continuously variable operating mode through selective actuation of a second one of the torque-transfer clutches.

8. Method for operating a powertrain comprising an internal combustion engine and first and second electrical machines and an electro-mechanical transmission selectively operative to transmit torque therebetween, the method comprising:

monitoring an operator torque request, a present transmission output speed and available battery power;

identifying at least one permissible powertrain operating range state comprising an engine-off state;

determining torque outputs from the first and second electrical machines to achieve a powertrain torque output to meet the operator torque request when the powertrain is operating in the permissible powertrain operating range state comprising the engine-off state;

determining an operating cost for operating the first and second electrical machines to achieve the powertrain torque output to meet the operator torque request in the permissible powertrain operating range state comprising the engine-off state, the operating cost associated with the present transmission output speed and the available battery power;

selecting the permissible powertrain operating range state comprising the engine-off state based upon the operating costs; and

,

controlling the powertrain in the engine-off state to meet the operator torque request.

9. The method of claim 8, wherein the permissible powertrain operating range state comprising the engine-off state further comprises a powertrain operating range state comprising one of a first and a second continuously variable operating mode.

10. The method of claim 8, wherein controlling the powertrain in the engine-off state comprises:

selectively actuating one of a plurality of torque-transfer clutches and deactivating the engine to achieve the engine-off state to transmit torque from the electric machines to substantially meet the operator torque request.

11. The method of claim 10, wherein the engine-off state comprises an engine crankshaft speed being zero revolutions per minute.