METHOD FOR CONTROLLING AN ENGINE FOR A MOTOR VEHICLE

• US 20130096808A1
• Filed: 10/11/2012
• Published: 04/18/2013
• Est. Priority Date: 10/12/2011
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Devonport, Peter Douglas, DeLaSalle, Stephen, Kaven, Chris John, Powell, Richard Andrew, Wood, Owen Fraser
• Granted Patent: US 9,031,766 B2
• Time in Patent Office: Days
• US Class Current: 701/110
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 2510/1005 Transmission ratio engaged
• CPC Class Codes: B60W 2530/16 Driving resistance
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2710/0666 Engine torque
• CPC Class Codes: B60W 2720/106 Longitudinal acceleration
• CPC Class Codes: F02D 2200/1002 Output torque
• CPC Class Codes: F02D 2250/26 by applying a torque limit
• CPC Class Codes: F02D 41/0225 in relation with the gear ratio or shift lever position

Abstract

A method for controlling the operation of an engine of a vehicle is disclosed in which a torque request signal supplied to control the supply of torque from the engine is adaptively modified based upon a desired maximum acceleration limit for the currently engaged gear and variations in the sum of forces resisting motion of the vehicle.

Claims

1. A method for controlling an engine of a motor vehicle having an engine driven transmission providing a number of gear ratios, comprising:

controlling the engine in response to a torque request, setting an acceleration limit based upon at least a current gear ratio, estimating a current road load for the motor vehicle and setting a maximum torque request limit based upon the estimated road load and the acceleration limit.

2. The method as claimed in claim 1, wherein the acceleration limit is based upon the current gear ratio and a current rotational speed of the engine.

3. The method as claimed in claim 1, wherein estimating the current road load comprises determining a current torque output from the engine, determining the acceleration of the motor vehicle due to the current torque output and using the values of acceleration and torque output to estimate road load.

4. The method as claimed in claim 1, wherein the method further comprises reducing the torque request from a demanded torque request to the maximum torque request limit if the demanded torque request exceeds the maximum torque request limit.

5. The method as claimed in claim 4, wherein the method further comprises reducing the torque request from the demanded torque request to a modified torque request if the demanded torque request exceeds a torque request limit that is lower than the maximum torque request limit.

6. The method as claimed in claim 5, wherein the torque request limit is related to the maximum torque request limit.

7. The method as claimed in claim 6 wherein the torque request limit is one of a predefined percentage and a predefined fraction of the maximum torque request limit.

8. The method as claimed in claim 5, wherein if the demanded torque request is less than the torque request limit, the torque request to the engine is the same as the demanded torque request.

9. The method as claimed in claim 4, wherein the demanded torque request is a torque demand from a driver of the motor vehicle.

10. The method as claimed in claim 4, wherein the demanded torque request is a torque demand from a cruise control of the motor vehicle.

11. A system for controlling operation of an engine of a motor vehicle having an engine driven transmission providing a number of gear ratios, the system comprising:

a main processor arranged to receive information regarding the current operating state of the engine and the current operating state of the motor vehicle, including current gear ratio and;

an engine control processor to control the operation of the engine in response to a torque request from the main processor, wherein the main processor is operable to set an acceleration limit for the motor vehicle based upon at least the current gear ratio, estimate a current road load for the motor vehicle, and set a maximum torque request limit based upon the estimated road load and the acceleration limit.

12. A system as claimed in claim 11, wherein the main processor is arranged to receive information regarding a current rotational speed of the engine and the current gear ratio, and is operable to set the acceleration limit for the motor vehicle based upon the current rotational speed of the engine and the current gear ratio.

13. A system as claimed in claim 11, in which the system includes a means for determining acceleration of the motor vehicle and the main processor is operable to use the torque request supplied to the engine control processor to estimate a current torque output from the engine, determine the acceleration of the motor vehicle in response to the torque output, and use the acceleration and torque output to estimate the current road load.

14. A system as claimed in claim 11, wherein if a demanded torque request is greater than the maximum torque request limit, the main processor is operable to reduce the demanded torque request to the maximum torque request limit.

15. A system as claimed in claim 14, wherein the main processor is further operable to reduce the demanded torque request to a modified torque request if the demanded torque request exceeds a torque request limit that is lower than the maximum torque request limit.

16. A system as claimed in claim 15, wherein the torque request limit is based upon the maximum torque request limit.

17. A system as claimed in claim 15, wherein the torque request limit is one of a predefined percentage and a predefined fraction of the maximum torque request limit.

18. A system as claimed claim 15, wherein if the demanded torque request is less than the torque request limit, the main processor is operable to supply a torque request to the engine control processor that is the same as the demanded torque request.

19. A system as claimed in claim 14, wherein the demanded torque request is one of a torque demand from a driver of the motor vehicle and a torque request from a cruise control of the motor vehicle.

20. A method, comprising:

limiting torque below that requested when above a threshold request;

the threshold increasing with increasing road load, and a degree of limiting reduced with higher road load and increased with higher discrete transmission gear ratios.