Vehicle brake control

• US 6,193,333 B1
• Filed: 06/24/1999
• Issued: 02/27/2001
• Est. Priority Date: 07/02/1998
• Status: Expired due to Term

• Current Assignee: Jaguar Land Rover Limited (TATA Motors Limited)
• Original Assignee: Rover Group Limited (Techtronic 2000 Plc)
• Inventors: Guest, Philip John
• Primary Examiner(s): Graham, Matthew C.
• Assistant Examiner(s): RODRIGUEZ, PAMELA
• Application Number:
  US09/339,671
• Time in Patent Office: 614 Days
• Field of Search: 303/2, 303/191, 303/138, 303/192, 303/199, 303/121, 303/125, 180/170, 701/70, 701/93, 701/96, 477/71, 477/73, 477/75
• US Class Current: 303/192
• CPC Class Codes: B60K 31/107 the memory being digital
• CPC Class Codes: B60T 13/686 in hydraulic systems or parts thereof
• CPC Class Codes: B60T 2201/04 Hill descent control
• CPC Class Codes: B60T 7/12 for automatic initiation; for initiation not subject to will of driver or passenger limiting speed of vehicles other than rail vehicles B60K31/00
• CPC Class Codes: B60T 8/00 Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force by changing number of effective brake cylinders in power brake systems B60T17/10
• CPC Class Codes: B60T 8/245 Longitudinal vehicle inclination
• CPC Class Codes: B60T 8/86 wherein the brakes are automatically applied in accordance with a speed condition and having means for overriding the automatic braking device when a skid condition occurs
• CPC Class Codes: B60W 2510/1005 Transmission ratio engaged
• CPC Class Codes: B60W 2720/106 Longitudinal acceleration
• CPC Class Codes: F16H 63/40 comprising signals other than signals for actuating the final output mechanisms

Abstract

An automatic brake control system for a vehicle in which the brakes 16, 17 are controlled by a control unit 22 to limit vehicle speed when descending a hill is provided with an input from a sensor on the gear selector 28. The control unit has a vehicle speed characteristic associated with each gear, the characteristics relating vehicle speed as controlled by the brake system to the position of the accelerator pedal, and having a different minimum speed for each gear.

Claims

1. A braking system for a vehicle having a transmission which can be shifted between a plurality of transmission ratios including a higher ratio and a lower ratio, the system comprising braking means, control means for controlling application of the braking means, and ratio detection means for detecting which ratio the transmission is operating in, wherein the control means defines a target speed and is arranged to control the braking means so as to maintain the speed of the vehicle at the target speed, the magnitude of the target speed is dependent on which transmission ratio is selected, and the target speed is higher when the higher ratio is selected than when the lower ratio is selected.

2. A system according to claim 1 wherein the control means is arranged, if the transmission is shifted between two of said ratios while the system is activated, to change the target speed thereby to change the speed at which the vehicle will travel.

3. A system according to claim 2 wherein the control means is arranged to change the target speed at a controlled rate thereby to limit at least one of the acceleration and deceleration rates of the vehicle as the target speed changes.

4. A system according to claim 1 for a vehicle which further comprises an accelerator wherein, in at least one of said transmission ratios, the target speed can be increased by operation of the accelerator.

5. A system according to claim 4 wherein, for each of said transmission ratios, the control means defines a characteristic relating the position of the accelerator to the target speed so that, in each of said ratios, the speed of the vehicle can be controlled by operation of the accelerator.

6. A braking system for a vehicle having wheels and a transmission which can be shifted between a plurality of transmission ratios including a higher ratio and a lower ratio, the system comprising brakes for braking the wheels, a controller for controlling application of the brakes, and a ratio detector for detecting at which ratio the transmission is operating, wherein the controller defines a target speed and a magnitude of the target speed is dependent on which transmission ratio is selected, the controller is arranged to control the brakes so as to maintain the speed of the vehicle at the target speed, and the target speed is higher when the higher ratio is selected than when the lower ratio is selected.

7. A system according to claim 6 wherein the controller is arranged, if the transmission is shifted between two of said ratios while the system is activated, to change the target speed thereby to change the speed at which the vehicle will travel.

8. A system according to claim 7 wherein the controller is arranged to change the target speed at a controlled rate thereby to limit at least one of an acceleration rate and a deceleration rate of the vehicle as the target speed changes.

9. A system according to claim 6 for a vehicle which further comprises an accelerator wherein, in at least one of said transmission ratios, the target speed can be increased by operation of the accelerator.

10. A system according to claim 9 wherein, for each of said transmission ratios, the controller defines a characteristic relating a position of the accelerator to the target speed so that, in each of said ratios, the speed of the vehicle can be controlled by operation of the accelerator.