FUEL ECONOMY WITH A DUAL OVERHEAD CAM ENGINE AND A STRONG HYBRID

• US 20110144838A1
• Filed: 12/10/2009
• Published: 06/16/2011
• Est. Priority Date: 12/10/2009
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (General Motors Company)
• Inventors: Matthews, Gregory P., Brennan, Daniel G.
• Granted Patent: US 8,527,120 B2
• Time in Patent Office: Days
• US Class Current: 701/22
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/443 Torque
• 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 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 2510/0657 Engine torque
• CPC Class Codes: B60W 2710/083 Torque
• CPC Class Codes: B60W 30/1882 characterised by the working point of the engine, e.g. by using engine output chart
• CPC Class Codes: F02D 2041/001 for engines with variable valve actuation
• CPC Class Codes: F02D 2250/21 during a transition between engine operation modes or states
• CPC Class Codes: F02D 2250/24 by using an external load, e.g. a generator
• CPC Class Codes: F02D 41/006 using internal EGR control of valve overlap for internal EGR F02D13/0261; arrangements for internal EGR F02M26/01
• CPC Class Codes: F16H 2037/106 with switching means to provide two variator modes or ranges
• 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

A method for controlling a powertrain includes operating an engine substantially at wide open throttle, monitoring an output torque request, controlling the engine input torque by controlling a valve overlap setting for a cylinder of the engine based upon the output torque request wherein controlling the valve overlap setting for the cylinder modulates a residual burnt gas fraction within the cylinder utilizing at least one of an extended low slope portion of an exhaust valve closing curve and an extended low slope portion of an intake valve opening curve, and controlling an electric machine input torque based upon the output torque request and a time-lag difference between the output torque request and the controlled engine input torque.

Claims

1. Method for controlling a powertrain comprising an electro-mechanical transmission, an internal combustion engine and an electric machine, the engine providing an engine input torque to the transmission and the electric machine providing an electric machine input torque to the transmission, the transmission providing an output torque comprising the engine and electric machine input torques, the method comprising:

operating the engine substantially at wide open throttle;

monitoring an output torque request;

controlling the engine input torque by controlling a valve overlap setting for a cylinder of the engine based upon the output torque request wherein controlling the valve overlap setting for the cylinder modulates a residual burnt gas fraction within the cylinder utilizing at least one of an extended low slope portion of an exhaust valve closing curve and an extended low slope portion of an intake valve opening curve; and

controlling the electric machine input torque based upon the output torque request and a time-lag difference between the output torque request and the controlled engine input torque.

2. The method of claim 1, wherein the extended low slope portions comprise a valve lift of less than 1 mm and a crank angle duration between about 75 degrees and 100 degrees.

3. The method of claim 1, wherein the valve overlap setting is determined from a look-up table.

4. The method of claim 1, wherein the valve overlap setting is determined from a programmed functional relationship of the output torque request, the engine input torque, and the residual burnt gas fraction.

5. The method of claim 1, wherein controlling the electric machine torque comprises feedback control.

6. The method of claim 1, wherein controlling the electric machine torque comprises feed forward control.

7. The method of claim 1, wherein operating said engine substantially at wide open throttle comprises operating said engine substantially at wide open throttle when the monitored output torque request exceeds a minimum output torque request.

8. The method of claim 1, wherein monitoring the output torque request comprises monitoring an accelerator pedal position.

9. The method of claim 1, wherein the modulated residual burnt gas fraction creates a dilutent to a subsequent unburned gas mixture in the cylinder.

10. The method of claim 1 wherein the powertrain further comprises a plurality of electric machines and controlling the electric machine input torque comprises controlling electric machine input torques of said plurality of electric machines.

11. Method for controlling a powertrain comprising an electro-mechanical transmission, an internal combustion engine and an electric machine, the engine providing an engine input torque to the transmission and the electric machine providing an electric machine input torque to the transmission, the transmission providing an output torque comprising the engine and electric machine input torques, the method comprising:

operating the engine substantially at wide open throttle;

monitoring an output torque request;

transitioning the engine input torque in response to the monitored output torque request by diluting an air fuel charge within a cylinder of the engine through controlling a valve overlap of an exhaust valve and an intake valve of the cylinder; and

during transitioning the engine input torque, controlling the electric machine input torque in response to the output torque request and the engine input torque.

12. The method of claim 11, wherein the valve overlap is provided by an extended low slope portion of an exhaust valve closing curve overlapping an intake valve opening curve.

13. The method of claim 11, wherein the valve overlap is provided by an extended low slope portion of an intake valve opening curve overlapping an exhaust valve closing curve.

14. The method of claim 12, wherein the intake valve opening curve comprises an extended low slope portion of the intake valve opening curve.

15. The method of claim 12, wherein the extended low slope portion comprises a valve lift of less than 1 mm and a crank angle duration between about 75 degrees and 100 degrees.

16. The method of claim 13, wherein the extended low slope portion comprises a valve lift of less than 1 mm and a crank angle duration between about 75 degrees and 100 degrees.

17. The method of claim 14, wherein the extended low slope portions comprise a valve lift of less than 1 mm and a crank angle duration between about 75 degrees and 100 degrees.

18. The method of claim 11, wherein controlling the electric machine input torque compensates for a difference between the output torque request and the engine input torque.

19. A powertrain system, comprising:

an electro-mechanical transmission;

an internal combustion engine providing an engine input torque to the transmission, said engine comprising a throttle device, a combustion chamber, an exhaust valve, an intake valve, an exhaust cam, an intake cam, an exhaust cam phaser adjusting the timing of the exhaust cam, and an intake cam phaser adjusting the timing of the intake cam, wherein at least one of the exhaust cam comprises an extended low slope portion of an exhaust valve closing profile and the intake cam comprises an extended low slope portion of an intake valve opening profile;

an electric machine providing an electric machine input torque to the transmission;

the transmission providing an output torque comprising the engine and electric machine input torques; and

a control module

operating the throttle device at a substantially wide open position,

monitoring an output torque request,

controlling the engine input torque comprising controlling at least one of the exhaust cam phaser and the intake cam phaser to effect a valve overlap setting controlling charge dilution in the combustion chamber, and

controlling the electric machine input torque based upon the output torque request and a time-lag difference between the output torque request and the engine input torque.

20. The powertrain system of claim 19, further comprising a plurality of electric machines.

21. The method of claim 19, wherein the extended low slope portions comprise a valve lift of less than 1 mm and a crank angle duration between about 75 degrees and 100 degrees.