Control system and method to inhibit automatic transmission downshifting during trailer sway

• US 8,060,288 B2
• Filed: 03/20/2009
• Issued: 11/15/2011
• Est. Priority Date: 03/20/2009
• Status: Active Grant

• Current Assignee: Toyota Motor Corporation
• Original Assignee: Toyota Motor Engineering & Manufacturing North America Incorporated (Toyota Motor Corporation)
• Inventors: Choby, Jordan
• Primary Examiner(s): Nguyen; Kim T
• Application Number:
  US12/408,476
• Publication Number:
  US 20100241319A1
• Time in Patent Office: 970 Days
• Field of Search: 701/48, 701/51, 701/70, 701/72, 701/74, 701/95
• US Class Current: 701/70
• CPC Class Codes: B60T 2230/06 Tractor-trailer swaying
• CPC Class Codes: B60T 2260/04 Automatic transmission
• CPC Class Codes: B60T 7/20 specially for trailers, e.g. in case of uncoupling of or overrunning by trailer inertia-actuated overrun brakes B60T13/08
• CPC Class Codes: B60T 8/1708 for lorries or tractor-trailer combinations
• CPC Class Codes: B60T 8/1755 Brake regulation specially adapted to control the stability of the vehicle, e.g. taking into account yaw rate or transverse acceleration in a curve road vehicle drive control systems for control of driving stability otherwise than by controlling a particular sub-unit B60W30/02
• CPC Class Codes: B60T 8/248 Trailer sway, e.g. for preventing jackknifing
• CPC Class Codes: F16H 61/16 Inhibiting or initiating shift during unfavourable conditions, e.g. preventing forward reverse shift at high vehicle speed, preventing engine over speed unintentional control input F16H61/18

Abstract

A control system for a vehicle that is towing a trailer, the control system including a lateral acceleration sensor coupled to the vehicle for determining a lateral acceleration of the vehicle caused by the trailer swaying and generating a lateral acceleration signal based on the lateral acceleration of the vehicle and a transmission controller for receiving the lateral acceleration signal from the lateral acceleration sensor, comparing the lateral acceleration signal to a threshold, and prohibiting a gear switch signal from being transmitted to a transmission of the vehicle when the lateral acceleration signal exceeds the threshold.

Claims

1. A control system for a vehicle that is towing a trailer comprising:

a lateral acceleration sensor coupled to the vehicle for determining a lateral acceleration of the vehicle caused by the trailer swaying and generating a lateral acceleration signal based on the lateral acceleration of the vehicle; and

a transmission controller for receiving the lateral acceleration signal from the lateral acceleration sensor, comparing the lateral acceleration signal to a threshold, and prohibiting a gear switch signal from being transmitted to a transmission of the vehicle when the lateral acceleration signal exceeds the threshold.

2. The control system of claim 1 wherein the lateral acceleration sensor determines a lateral acceleration of the vehicle in both opposite directions.

3. The control system of claim 1 wherein the gear switch signal is a downshift signal.

4. The control system of claim 1 wherein the transmission is an electronically controlled transmission that is configured to transmit a gear change request to the transmission controller.

5. The control system of claim 4 further comprising a transmission speed sensor coupled to the transmission for determining a speed of the transmission, generating a transmission speed signal representing the speed of the transmission, and transmitting the transmission speed signal to the transmission controller.

6. The control system of claim 5 wherein the transmission controller uses the gear change request, the transmission speed signal and the lateral acceleration signal to determine whether or not to transmit a downshift signal to the transmission.

7. The control system of claim 6 wherein upon receiving the downshift signal, the transmission causes a mechanical or electrical change of a gear.

8. A control system for a vehicle that is towing a trailer comprising:

a lateral acceleration sensor for generating a lateral acceleration signal based on a lateral acceleration of a vehicle caused by the trailer swaying;

a yaw rate sensor for generating a yaw signal based on an angular velocity of the vehicle;

a stability control system for receiving the lateral acceleration signal and the yaw signal, comparing the lateral acceleration signal to a first threshold value, comparing the yaw signal to a second threshold value, and generating a prohibit downshift signal when the lateral acceleration signal exceeds the first threshold value or when the yaw signal exceeds the second threshold value; and

a transmission controller for receiving the prohibit downshift signal from the stability control system and transmitting a prohibit downshift signal to a transmission of the vehicle to prevent a mechanical or electrical change of a gear of the transmission.

9. The control system of claim 8 wherein the lateral acceleration sensor determines a lateral acceleration of the vehicle in both opposite directions.

10. The control system of claim 8 wherein the transmission is an electronically controlled transmission that is configured to transmit a gear change request to the transmission controller.

11. The control system of claim 8 further comprising a transmission speed sensor coupled to the transmission for determining a speed of the transmission, generating a transmission speed signal representing the speed of the transmission, and transmitting the transmission speed signal to the transmission controller.

12. The control system of claim 8 further comprising a steering wheel angle sensor for generating a steering wheel angle signal based on an angle in which a steering wheel of the vehicle has rotated from a center position and transmitting the steering wheel angle signal to the stability control system.

13. The control system of claim 12 further comprising a wheel speed sensor for generating a wheel speed signal for each wheel of the vehicle and transmitting the wheel speed signals to the stability control system.

14. The control system of claim 13 further comprising a brake sensor for generating a brake signal indicating whether the brakes have been applied and transmitting the brake signal to the stability control system.

15. The control system of claim 14 further comprising a brake pressure sensor for generating a brake pressure signal indicating an amount of pressure being applied to the brakes of the vehicle and transmitting the brake pressure signal to the stability control system.

16. The control system of claim 15 wherein the stability control system receives the steering wheel angle signal, the wheel speed signals, the brake signal, and the brake pressure signal, compares the steering wheel angle signal to a third threshold value, compares the wheel speed signals to a fourth threshold value, compares the brake signal to a fifth threshold value, compares the brake pressure signal to a sixth threshold value, and generates a prohibit downshift signal when the steering wheel angle signal exceeds the third threshold value, at least one of the wheel speed signals exceeds the fourth threshold value, the brake signal exceeds the fifth threshold value or the brake pressure signal exceeds the sixth threshold value.

17. A method of controlling vehicle stability during trailer sway, the method comprising:

receiving from a lateral acceleration sensor a lateral acceleration signal measuring a lateral acceleration of a vehicle;

receiving from a yaw sensor a yaw signal measuring an angular velocity of the vehicle; and

generating a prohibit downshift signal when the lateral acceleration signal exceeds a first threshold value or when the yaw signal exceeds a second threshold value.

18. The method of claim 17 further comprising transmitting the prohibit downshift signal to a transmission controller to prevent a gear downshift of a transmission of the vehicle.

19. The method of claim 17 further comprising receiving from a wheel speed sensor a wheel speed signal indicating whether wheel skidding or spinning is occurring and generating a prohibit downshift signal if wheel skidding or spinning is detected.

20. The method of claim 17 further comprising transmitting the prohibit downshift signal to a transmission of the vehicle to prevent a mechanical or electrical change of a gear of the transmission.