METHOD AND ARRANGEMENT FOR CONTROLLING ACTUAL TORQUE IN A LAND VEHICLE DRIVELINE

• US 20060116806A1
• Filed: 02/13/2006
• Published: 06/01/2006
• Est. Priority Date: 08/27/2003
• Status: Active Grant

• Current Assignee: Volvo Lastvagnar AB (AB Volvo)
• Original Assignee: Volvo Lastvagnar AB (AB Volvo)
• Inventors: Steen, Marcus, Eriksson, Anders
• Granted Patent: US 7,440,832 B2
• Time in Patent Office: Days
• US Class Current: 701/51
• CPC Class Codes: B60W 10/04 including control of propulsion units
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/10 including control of change-speed gearings
• CPC Class Codes: B60W 10/101 Infinitely variable gearings
• CPC Class Codes: B60W 2510/0657 Engine torque
• CPC Class Codes: B60W 2710/0666 Engine torque
• CPC Class Codes: B60W 30/18136 Engine braking
• CPC Class Codes: B60W 30/1819 Propulsion control with control means using analogue circuits, relays or mechanical links
• CPC Class Codes: B60W 30/184 Preventing damage resulting from overload or excessive wear of the driveline
• CPC Class Codes: F02D 2200/1002 Output torque
• CPC Class Codes: F02D 2250/18 Control of the engine 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
• CPC Class Codes: F02D 41/1497 With detection of the mechanical response of the engine

Abstract

Method and arrangement for controlling actual torque in a driveline of a land-based motor vehicle. Taking a direct, non-predictive measure of actual torque induced in the driveline of the motor vehicle and ascertaining a magnitude thereof. Ascertaining a magnitude of a torque demand being requested to be instituted in the driveline. Comparing the ascertained magnitude of the direct, non-predictive measure of actual torque taken is compared with a driveline-configuration dependent maximum torque threshold; in this way, an over-threshold torque condition is ascertained in the driveline based thereupon if such a condition exists. In multi-geared transmissions, the variability can be accounted for through the engagement of different ratio gears. In the event that such an over-threshold torque condition is detected, at least one of several possible over-threshold torque compensating effects will be applied to reduce or diminish the excessive portion of the torque. The remedial measure may be chosen from several possibilities including reconfiguring the variable ratio transmission and/or reducing powerplant-induced driveline torque.

Claims

1. A method for controlling actual torque in a driveline of a land-based motor vehicle, the motor vehicle including a drivetrain having a powerplant interconnected with at least one ground engaging drive wheel via a driveline, the driveline including at least a variable ratio transmission, the method comprising the steps of:

taking a direct, non-predictive measure of actual torque induced in the driveline of the motor vehicle and ascertaining a magnitude thereof;

ascertaining a magnitude of a torque demand being requested to be instituted in the driveline;

comparing the ascertained magnitude of the direct, non-predictive measure of actual torque taken with a driveline-configuration dependent maximum torque threshold and thereby ascertaining an over-threshold torque condition in the driveline based thereupon; and

applying at least one over-threshold torque compensating effect chosen from the group comprising (a) reconfiguring the variable ratio transmission and (b) reducing powerplant-induced driveline torque.

2. The method as recited in claim 1, further comprising determining, prior to choosing reconfiguration of the variable ratio transmission, that, based on existing vehicle operating conditions and the magnitude of the torque demand being requested to be instituted in the driveline, a plurality of acceptable configurations of the variable ratio transmission exist that diminish the ascertained over-threshold torque condition in the driveline;

and selecting among the plurality of acceptable configurations of the variable ratio transmission one that provides a best-fit with prescribed operational criteria.

3. The method as recited in claim 1, further comprising determining, prior to choosing reconfiguration of the variable ratio transmission, that, based on existing vehicle operating conditions and the magnitude of the torque demand being requested to be instituted in the driveline, at least one acceptable configuration of the variable ratio transmission exists that diminishes the ascertained over-threshold torque condition in the driveline.

4. The method as recited in claim 3, further comprising reconfiguring the variable ratio transmission to the at least one acceptable configuration of the variable ratio transmission determined to diminish the ascertained over-threshold torque condition in the driveline.

5. The method as recited in claim 1, further comprising utilizing a torque sensor positioned at the driveline to measure the actual torque induced in the driveline of the motor vehicle.

6. The method as recited in claim 5, further comprising tuning the powerplant, on an after-market basis, thereby achieving greater powerplant output capacity without risk of detrimental affect on the driveline of the motor vehicle.

7. The method as recited in claim 5, further comprising facilitating the pairing of an over-capacity powerplant with a relative under capacity driveline.

8. The method as recited in claim 5, further comprising facilitating the pairing of a powerplant having a capacity for producing torque of magnitude greater than a paired driveline is capable of accommodating.

9. The method as recited in claim 5, further comprising preventing erroneous detection of over-threshold torque conditions in the driveline thereby avoiding detrimental reductions of powerplant output when not required.

10. The method as recited in claim 1, further comprising reducing the driveline-configuration dependent maximum torque threshold based on an ascertainment that the driveline is not fully broken in.

11. The method as recited in claim 1, further comprising reducing the driveline-configuration dependent maximum torque threshold based on an ascertainment that a temperature of the driveline is below a prescribed operating temperature.

12. The method as recited in claim 1, further comprising adjusting the driveline-configuration dependent maximum torque threshold based on a locked status of a differential interconnected with the driveline.

13. The method as recited in claim 1, further comprising increasing the driveline-configuration dependent maximum torque threshold thereby enabling greater engine braking capacity and reducing the service life period of the driveline.

14. The method as recited in claim 1, further comprising decreasing the driveline-configuration dependent maximum torque threshold thereby reducing engine braking capacity and increasing the service life period of the driveline.

15. The method as recited in claim 1, wherein the step of choosing an over-threshold torque compensating effect comprises choosing reconfiguring the ratio of the variable ratio transmission.

16. The method as recited in claim 1, further comprising ascertaining a plurality of threshold torque capacities of the driveline, each dependent upon discreet and different configurations of the variable ratio transmission;

determining which ratio configuration would produce a least-excessive torque magnitude based on a comparison between the determined torque demand and the plurality of threshold torque capacities; and

reconfiguring the variable ratio transmission to the determined ratio configuration thereby producing a minimized over-threshold torque sufficient to satisfy the torque demand magnitude and mechanically preserving the driveline.

17. The method as recited in claim 1, further comprising executing the taking a direct, non-predictive measure of actual torque induced in the driveline of the motor vehicle and ascertaining a magnitude thereof when a travel-retarding torque is being imposed on the driveline by the powerplant that is in an engine-braking mode.

18. The method as recited in claim 17, further comprising ascertaining an engine brake demand magnitude and a speed of the motor vehicle;

determining whether the variable ratio transmission includes a ratio configuration compatible with the ascertained speed of the motor vehicle which will produce a non-excessive torque magnitude in the driveline; and

reconfiguring the variable ratio transmission to the compatible ratio configuration that produces the non-excessive torque magnitude thereby mechanically preserving the driveline.

19. The method as recited in claim 17, further comprising ascertaining an engine brake demand magnitude and a speed of the motor vehicle;

determining whether the variable ratio transmission includes a ratio configuration compatible with the ascertained speed of the motor vehicle which will produce a least-excessive torque magnitude in the driveline; and

reconfiguring the variable ratio transmission to the compatible ratio configuration that produces the least-excessive torque magnitude thereby mechanically preserving the driveline.

20. The method as recited in claim 17, further comprising ascertaining an engine brake demand magnitude;

determining, of all possible ratio configurations of the variable ratio transmission, which ratio configuration would produce a least-excessive torque magnitude in the driveline of the motor vehicle; and

reconfiguring the variable ratio transmission to the determined ratio configuration thereby producing sufficient engine braking torque and mechanically preserving the driveline.

21. The method as recited in claim 17, further comprising ascertaining an engine brake demand magnitude and determining a corresponding torque demand required to be induced in the driveline to produce the engine brake demand magnitude;

ascertaining a plurality of threshold torque capacities of the driveline, each dependent upon discreet and different configurations of the variable ratio transmission;

determining which ratio configuration would produce a least-excessive torque magnitude based on a comparison between the determined torque demand and the plurality of threshold torque capacities; and

reconfiguring the variable ratio transmission to the determined ratio configuration thereby producing a minimized over-threshold engine braking torque sufficient to satisfy the engine brake demand magnitude and mechanically preserving the driveline.

22. The method as recited in claim 17, further comprising ascertaining an engine brake demand magnitude and determining a corresponding torque demand required to be induced in the driveline to produce the engine brake demand magnitude;

ascertaining a plurality of threshold torque capacities of the driveline, each dependent upon discreet and different configurations of the variable ratio transmission;

determining which ratio configuration would produce a least-deficient torque magnitude based on a comparison between the determined torque demand and the plurality of threshold torque capacities; and

reconfiguring. the variable ratio transmission to the determined ratio configuration thereby producing a minimized under-threshold engine braking torque and mechanically preserving the driveline.

23. The method as recited in claim 17, further comprising ascertaining an engine brake demand magnitude and determining a corresponding torque demand required to be induced in the driveline to produce the engine brake demand magnitude;

ascertaining a plurality of threshold torque capacities of the driveline, each dependent upon discreet and different configurations of the variable ratio transmission;

determining which ratio configuration would produce a least-different torque magnitude based on a comparison between the determined torque demand and the plurality of threshold torque capacities; and

reconfiguring the variable ratio transmission to the determined ratio configuration thereby producing sufficient engine braking torque and mechanically preserving the driveline.

24. The method as recited in claim 23, further comprising considering, in the ascertainment of the plurality of threshold torque capacities of the driveline, an operational condition of the driveline that is variable.

25. The method as recited in claim 24, further comprising selecting the variable operational condition of the driveline to be a measured current period of operation of the driveline.

26. The method as recited in claim 24, further comprising selecting the variable operational condition of the driveline to be a measured operating temperature of the driveline.

27. The method as recited in claim 24, further comprising selecting the variable operational condition of the driveline to be a measured in-service life of the driveline.

28. The method as recited in claim 27, further comprising basing the in-service life measurement of the driveline on a signal of a sensor selected from a group consisting of an odometer, a shaft revolution counter, a vehicle speed sensor, a driven wheel speed sensor, a drive wheel speed sensor.

29. A land vehicle drivetrain control device comprising a processor and readable medium configured and programmed to execute the method recited in claim 1.

30. A land vehicle having a drivetrain and control device therefore, the control device comprising a processor and readable medium configured and programmed to execute the method recited in claim 1.

31. A computer readable medium comprising program code adapted to, upon execution on a computer, perform the method recited in claim 1.

32. A computer program product comprising program code on a computer readable medium for performing the method recited in claim 1 when executed on a computer.

33. A computer program product directly loadable into the internal memory of a digital computer, comprising software code portions for performing the method recited claim 1 when executed on a computer.