Control system for a continuously variable transmission in a vehicle propulsion system

Patent metadata

Field	Value
Publication number	US-10518778-B2
Application number	US-201715791681-A
Country	US
Kind code	B2
Filing date	Oct 24, 2017
Priority date	Oct 24, 2017
Publication date	Dec 31, 2019
Grant date	Dec 31, 2019

Abstract

A vehicle propulsion system includes a prime mover having a prime mover output shaft, a continuously variable transmission having a variator input shaft coupled to the prime mover output shaft and having a variator output shaft, a driver torque request module in communication with a driver input and for outputting a driver torque request, an engine backbone in communication with the prime mover, and a transmission backbone in communication with the continuously variable transmission and the engine backbone in the vehicle propulsion system. The transmission backbone includes a positive torque request module that generates a positive torque request, and a positive torque request monitor that limits a torque request from the transmission backbone to the engine backbone to a maximum of a predetermined threshold.

First claim

What is claimed is:

1. A vehicle propulsion system, the system comprising:
a prime mover having a prime mover output shaft;
a continuously variable transmission having a variator input shaft coupled to the prime mover output shaft and having a variator output shaft;
a driver torque request module in communication with a driver input and for outputting a driver torque request;
an engine control module set in communication with the prime mover; and
a transmission control module set in communication with the continuously variable transmission and the engine control module set in the vehicle propulsion system, the transmission control module set including:
a positive torque request module that generates a positive torque request; and
a positive torque request monitor that limits a torque request from the transmission control module set to the engine control module set to a maximum of a predetermined threshold, wherein the torque request is a sum of the driver torque request and the positive torque request.

2. The system of claim 1 , wherein the positive torque request module determines the positive torque request based upon an engine acceleration and an engine inertia.

3. The system of claim 2 , wherein the positive torque request module determines the positive torque request during a decrease in speed ratio of the continuously variable transmission such that a net torque at an axle of the vehicle propulsion system substantially matches a driver requested axle torque.

4. The system of claim 3 , wherein the driver requested axle torque corresponds to the driver torque request.

5. The system of claim 1 , wherein the positive torque request monitor limits a torque request from the transmission control module set to the engine control module set to a maximum of a predetermined threshold from a table of predetermined threshold values.

6. The system of claim 5 , wherein the positive torque request monitor determines the predetermined threshold from the table based upon an engine acceleration and a ratio of the continuously variable transmission.

7. A controller for a vehicle propulsion system in a vehicle, the controller comprising:
an engine control module set in communication with the prime mover; and
a transmission control module set in communication with the continuously variable transmission and the engine control module set in the vehicle propulsion system, the transmission control module set including:
a positive torque request module that generates a positive torque request; and
a positive torque request monitor that limits a torque request from the transmission control module set to the engine control module set to a maximum of a predetermined threshold, wherein the positive torque request monitor limits the torque request from the transmission control module set to the engine control module to a torque request that is a sum of the driver torque request and the positive torque request and to a maximum of the predetermined threshold.

8. The system of claim 7 , wherein the positive torque request module determines the positive torque request based upon an engine acceleration and an engine inertia.

9. The system of claim 8 , wherein the positive torque request module determines the positive torque request during a decrease in speed ratio of the continuously variable transmission such that the net torque at an axle of the vehicle propulsion system substantially matches a driver requested axle torque.

10. The system of claim 9 , wherein the driver requested axle torque corresponds to the driver torque request.

11. The system of claim 7 , wherein the positive torque request monitor that limits a torque request from the transmission control module set to the engine control module set to a maximum of a predetermined threshold from a table of predetermined threshold values.

12. The system of claim 11 , wherein the positive torque request monitor determines the predetermined threshold from the table based upon an engine acceleration and a ratio of the continuously variable transmission.

13. A method for controlling a vehicle propulsion system which includes a prime mover having a prime mover output shaft, a continuously variable transmission having a variator input shaft coupled to the prime mover output shaft and having a variator output shaft, the method comprising:
generating a positive torque request in a transmission control module set; and
monitoring a torque request from the transmission control module set to an engine control module set to ensure that the torque request does not exceed a predetermined threshold, wherein the torque request comprises a sum of the positive torque request and a driver torque request.

14. The method of claim 13 , wherein generating the positive torque request is during a decrease in speed ratio of the continuously variable transmission such that a net torque at an axle of the vehicle propulsion system substantially matches a driver requested axle torque.

15. The method of claim 14 , wherein the driver requested axle torque corresponds to the driver torque request.

16. The method of claim 13 , wherein the monitoring of the torque request to ensure that the torque request does not exceed a predetermined threshold further comprises referencing a table of predetermined threshold values.

17. The method of claim 16 , wherein referencing the table is based upon an engine acceleration and a ratio of the continuously variable transmission.

Assignees

• Gm Global Tech Operations Llc

Inventors

• Lochocki Jr Ronald F
• Weingartz Christopher J
• Keller Bret J

Classifications

• B60W2540/10

  Accelerator pedal position · CPC title

• B60W2710/0666

  Engine torque · CPC title

• B60W30/188 Primary

  Controlling power parameters of the driveline, e.g. determining the required power · CPC title

• B60W2720/30

  Wheel torque · CPC title

• B60W10/107

  with endless flexible members · CPC title