METHOD OF CONTROLLING VEHICLE WHEEL AXLE TORQUE AND CONTROL SYSTEM FOR SAME

• US 20130096797A1
• Filed: 10/13/2011
• Published: 04/18/2013
• Est. Priority Date: 10/13/2011
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Whitney, Christopher E., Jess, Richard B., Durkin, Thomas Richard, Abdow, Danny
• Granted Patent: US 8,577,578 B2
• Time in Patent Office: Days
• US Class Current: 701/87
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60W 10/105 of electric type
• 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 2520/06 Direction of travel
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2540/16 Ratio selector position
• CPC Class Codes: B60W 2710/105 Output torque
• CPC Class Codes: B60W 30/18036 Reversing
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

A method of controlling torque on a vehicle wheel axle includes comparing a torque intervention request to a predetermined minimum axle torque for a current vehicle speed and a current direction of motion of the vehicle. The predetermined minimum axle torque decreases as vehicle speed in an operator-selected direction of motion increases. An arbitrated axle torque is calculated based on an operator-requested torque, the current vehicle speed, the current direction of motion, and the greater of the torque intervention request and the predetermined minimum torque. Axle torque is applied to the vehicle'"'"'s wheel axle based at least partially on the arbitrated axle torque.

Claims

1. A method of controlling torque on a wheel axle comprising:

comparing at least one torque intervention request to a predetermined minimum axle torque for a current vehicle speed and a current direction of motion of the vehicle;

wherein the predetermined minimum axle torque decreases as vehicle speed in an operator-selected direction of motion increases;

calculating via a controller an arbitrated axle torque based on an operator-requested axle torque, the current vehicle speed, the current direction of motion, and the greater of said at least one torque intervention request and the predetermined minimum axle torque; and

applying axle torque to the wheel axle based at least partially on the arbitrated axle torque.

2. The method of claim 1, wherein the predetermined minimum axle torque is limited to a value greater than a predetermined threshold value for all vehicle speeds, thereby limiting maximum vehicle deceleration.

3. The method of claim 1, wherein said at least one torque intervention request includes at least one of a vehicle overspeed system torque request, a traction or stability control system torque request, a brake torque control system torque request, and a vehicle speed limiter system torque request.

4. The method of claim 1, wherein said predetermined minimum axle torque functions as a creep coast system torque limit at vehicle speeds below a first threshold speed.

5. A method of controlling wheel axle torque comprising:

determining an operator-selected direction of motion for a vehicle;

determining vehicle speed;

determining an actual direction of motion of the vehicle;

comparing at least one torque intervention request to a predetermined axle torque limit for the vehicle speed and the actual direction of motion;

calculating via a controller an arbitrated axle torque;

wherein the arbitrated axle torque is based on an operator-requested axle torque and said at least one torque intervention request if said at least one torque intervention request is greater than the predetermined axle torque limit;

wherein the arbitrated axle torque is based on the operator-requested axle torque and the predetermined axle torque limit if said at least one torque intervention request is not greater than the predetermined axle torque limit; and

applying the arbitrated axle torque to a wheel axle of the vehicle, thereby preventing motion of the vehicle in a direction opposite the operator-selected direction of motion.

6. The method of claim 5, wherein the predetermined axle torque limit increases as vehicle speed decreases when vehicle speed is below a predetermined threshold speed and also when the actual direction of motion of the vehicle is opposite to the operator-selected direction of motion.

7. The method of claim 5, wherein the predetermined axle torque limit decreases up to a predetermined threshold value as vehicle speed increases when the actual direction of motion and the operator-selected direction of motion are the same.

8. The method of claim 5, wherein the predetermined axle torque limit functions as a creep coast system torque limit at vehicle speeds below a predetermined threshold speed.

9. The method of claim 5, wherein said at least one torque intervention request includes a vehicle overspeed system torque request.

10. The method of claim 5, wherein said at least one torque intervention request includes a traction or stability control system torque request.

11. The method of claim 5, wherein said at least one torque intervention request includes a brake torque control system torque request.

12. The method of claim 5, wherein said at least one torque intervention request includes a vehicle speed limiter system torque request.

13. A system for controlling wheel axle torque comprising:

a driver-operated shift lever operable to establish an intended direction of motion of the vehicle;

a driver-operated accelerator device operable to establish a desired axle torque;

at least one torque control system operable to establish a torque intervention request;

a first controller operatively connected with the driver-operated shift lever, with the driver-operated accelerator device, and with said at least one torque control system;

wherein the first controller has a processor with;

a first algorithm that;

compares said at least one torque intervention request to a predetermined minimum axle torque that decreases as vehicle speed in the intended direction of motion increases above a predetermined threshold speed, that increases as vehicle speed in the intended direction of motion and below the predetermined minimum speed increases, and that increases as vehicle speed in a direction of motion opposite the intended direction of motion increases;

determines the greater of said at least one torque intervention request and said predetermined minimum axle torque; and

calculates an arbitrated axle torque based on said desired axle torque and the greater of said at least one torque intervention request and said predetermined minimum axle torque; and

a second controller operatively connected with the first controller;

wherein the second controller receives a signal corresponding with the arbitrated axle torque from the first controller and has;

a second algorithm that determines how to establish the arbitrated axle torque to be applied to a vehicle axle.

14. The control system of claim 13, wherein the predetermined minimum axle torque is limited to a value greater than a predetermined threshold value.

15. The control system of claim 13, wherein said at least one torque control system is one of a vehicle overspeed system, a traction or stability control system, a brake torque control system, and a vehicle speed limiter system.