Vehicle control system

• US 9,821,778 B2
• Filed: 02/23/2016
• Issued: 11/21/2017
• Est. Priority Date: 02/23/2016
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Frijas, Rodney M., Zimmerman, Rob S., Raymond, Chad D., Sovern, Jason A.
• Primary Examiner(s): Dager, Jonathan M
• Assistant Examiner(s): Evans, Garrett F
• Application Number:
  US15/051,066
• Publication Number:
  US 20170240146A1
• Time in Patent Office: 637 Days
• Field of Search: None
• CPC Class Codes: B60T 2201/06 Hill holder; Start aid systems on inclined road
• CPC Class Codes: B60T 7/122 for locking of reverse movement
• CPC Class Codes: B60T 8/245 Longitudinal vehicle inclination

Abstract

A Hill Start Assist (HSA) system for an off-road type vehicle includes a brake system for producing a braking force sufficient to maintain the vehicle in a stopped condition, and a control unit in communication with the brake system for controlling a brake modulator of the brake system to maintain the braking force when a manual brake actuator of the brake system is in a released position. The HSA system is operable in a ready state where the brake modulator is in an open condition and the braking force is not maintained, an activated state and a hold state where the brake modulator is in a closed condition and the braking force is maintained. The HSA system is only in the ready state upon determination by the control unit that predetermined vehicle conditions are satisfied.

Claims

1. A Hill Start Assist (HSA) system for an off-road type vehicle comprising:

a brake system for producing a braking force sufficient to maintain the vehicle in a stopped condition, and a control unit in communication with the brake system for controlling a brake modulator of the brake system to maintain the braking force when a manual brake actuator of the brake system is in a released position,

wherein the HSA system is operable in a ready state where the brake modulator is in an open condition and the braking force is not maintained, an activated state and a hold state where the brake modulator is in a closed condition and the braking force is maintained, wherein the HSA system is only in the ready state upon determination by the control unit that predetermined vehicle conditions are satisfied, wherein the predetermined vehicle conditions include the vehicle being in the stopped condition, the manual brake actuator being in an engaged position, an acceleration pedal being in a released position, and a HSA switch being manually activated by an associated vehicle operator,

wherein the control unit is adapted to move the HSA system from the activated state to the hold state upon determining that the manual brake actuator is in the released position, and the control unit is adapted to move the HSA system from the hold state to the activated state upon determining that the manual brake actuator is again in the engaged position.

2. The system of claim 1, further including at least one vehicle wheel speed sensor operable to detect wheel speed of at least one wheel, wherein the control unit is in signal communication with the at least one wheel speed sensor and is configured to determine based on a signal from the at least one wheel speed sensor whether the vehicle is in the stopped condition.

3. The system of claim 1, wherein the brake system includes a master brake cylinder, the brake modulator controlling a brake pressure of the master brake cylinder, and a brake sensor in signal communication with the control unit and operable to detect the brake pressure of the master brake cylinder, wherein a determination by the control unit of whether the manual brake actuator is in one of the released position and the engaged position is based on a comparison by the control unit of detected brake pressure and a predetermined brake pressure.

4. The system of claim 1, wherein the brake system further includes a brake light switch, the brake light switch being in an activated condition when vehicle brakes of the brake system are applied, wherein the predetermined vehicle conditions further includes the control system determining that the brake light switch is in the activated condition.

5. The system of claim 1, wherein the HSA system includes a deactivated state, and the control unit is adapted to determine that each of the predetermined vehicle conditions has been satisfied for a first time period prior to the HSA system moving from the deactivated state to the ready state.

6. The system of claim 1, wherein the HSA system includes a deactivated state, and the control unit is adapted to move the HSA system to the deactivated state from any one of the ready, activated and hold states upon the control unit determining that the HSA switch is again activated by the associated vehicle driver.

7. The system of claim 1, further including an acceleration sensor in signal communication with the control unit and operable to detect displacement of the acceleration pedal, wherein the control unit is in signal communication with the acceleration sensor and is configured to determine based on a signal from the acceleration sensor whether the acceleration pedal is in one of the released position and a depressed position.

8. The system of claim 7, wherein the HSA system includes a deactivated state, and the control unit is adapted to move the HSA system to the deactivated state from any one of the ready, activated and hold states upon the control unit determining that the vehicle is not in the stopped condition and the acceleration pedal is in the depressed position.

9. The system of claim 1, wherein the HSA system includes a deactivated state, and the control unit is adapted to move the HSA system to the deactivated state from one of the ready and hold states upon expiration of a time period.

10. The system of claim 1, further including a first indication signal having an on/off condition and an intermittent on condition, wherein the first indication signal is in the on condition when the HSA system is in one of the ready and activated states.

11. The system of claim 10, wherein the first indication signal is in the intermittent on condition when the HSA system is in the hold state.

12. A method of controlling a Hill Start Assist (HSA) system for an off-road type vehicle comprising:

controlling a brake modulator of a brake system to maintain a braking force sufficient to maintain the vehicle in a stopped condition when a manual brake actuator of the brake system is in a released position;

transitioning the HSA system from a deactivated state to a ready state by determining that the vehicle is in the stopped condition, the manual brake actuator is in an engaged position, an acceleration pedal is in a released position, and a HSA switch is manually activated by an associated vehicle operator;

transitioning the HSA system from the ready state to an activated state where the brake modulator is in a closed condition and the braking force is maintained; and

transitioning the HSA system from the activated state to a hold state where the brake modulator remains in the closed position by determining that the manual brake actuator is in the released position; and

transitioning the HSA system from the hold state back to the deactivated state.

13. The method of claim 12, wherein transitioning the HSA system from the activated state to a hold state is based on determining the manual brake actuator is in the released position.

14. The method of claim 12, further including transitioning the HSA system from the hold state to the activated state is based on determining the manual brake actuator is in the engaged position.

15. The method of claim 12, further including transitioning the HSA system from any one of the ready, activated and hold states to the deactivated state based on determining one of the HSA switch is again activated by the associated vehicle driver, the vehicle not being in the stopped and the acceleration pedal is in a depressed position.

16. The method of claim 12, further including transitioning the HSA system from any one of the activated state and the hold state to the deactivated state based on determining that a time period is expired.

17. A Hill Start Assist (HSA) system for an off-road type vehicle comprising:

a brake system for producing a braking force sufficient to maintain the vehicle in a stopped condition, and a control unit in communication with the brake system for controlling a brake modulator of the brake system to maintain the braking force when a manual brake actuator of the brake system is in a released position,

wherein the HSA system is operable in a ready state where the brake modulator is in an open condition and the braking force is not maintained, an activated state where the brake modulator is in a closed condition, a deactivated state, and a hold state where the brake modulator remains in the closed condition, the manual brake actuator remains in the released position, and the braking force is maintained, wherein the HSA system is only in the ready state upon determination by the control unit that predetermined vehicle conditions are satisfied, wherein the predetermined vehicle conditions include the vehicle being in the stopped condition, the manual brake actuator being in an engaged position, an acceleration pedal being in a released position, and a HSA switch being manually activated by an associated vehicle operator,

wherein the control unit is adapted to move the HSA system to the deactivated state from any one of the ready, activated and hold states upon the control unit determining that the HSA switch is again activated by the associated vehicle driver.

18. The system of claim 17, wherein the brake system includes a master brake cylinder, the brake modulator controlling a brake pressure of the master brake cylinder, and a brake sensor in signal communication with the control unit and operable to detect the brake pressure of the master brake cylinder, wherein a determination by the control unit of whether the manual brake actuator is in one of the released position and the engaged position is based on a comparison by the control unit of detected brake pressure and a predetermined brake pressure,

wherein the control unit is adapted to move the HSA system from the activated state to the hold state upon determining based on a signal received from the brake sensor that the manual brake actuator is in the released position, and

wherein the control unit is adapted to move the HSA system from the hold state to the activated state upon determining based on a signal received from the brake sensor that the manual brake actuator is again in the engaged position.