Vehicle braking

• US 6,505,894 B2
• Filed: 03/12/2001
• Issued: 01/14/2003
• Est. Priority Date: 03/14/2000
• Status: Expired due to Term

• Current Assignee: Jaguar Land Rover Limited (TATA Motors Limited)
• Original Assignee: Land Rover (TATA Motors Limited)
• Inventors: Fawkes, Paul Antony, Dunning, Simon Michael
• Primary Examiner(s): Schwartz, Christopher P.
• Application Number:
  US09/804,517
• Publication Number:
  US 20010022470A1
• Time in Patent Office: 673 Days
• Field of Search: 303/9.62, 303/9.69, 303/9.71, 303/140, 303/146, 303/186, 303/190, 303/191
• US Class Current: 303/186
• CPC Class Codes: B60T 2201/16 Curve braking control, e.g. turn control within ABS control algorithm
• CPC Class Codes: B60T 8/1766 Proportioning of brake forces according to vehicle axle loads, e.g. front to rear of vehicle
• CPC Class Codes: B60T 8/241 Lateral vehicle inclination
• CPC Class Codes: B60T 8/246 Change of direction
• CPC Class Codes: B60T 8/268 using the valves of an ABS, ASR or ESP system

Abstract

In a vehicle braking system with electronic brake distribution the threshold level of slip of the rear wheels is increased when the front brake temperature is estimated to have increased to a level where brake fade will occur. This allows more braking torque to be applied to the rear wheels to counteract the brake fade at the front wheels. This increase in threshold slip is, however, overridden if the vehicle is cornering, as detected by a lateral accelerometer or a wheel speed difference across the vehicle, to avoid a reduction in vehicle stability during cornering.

Claims

1. A braking system for a vehicle having a front wheel and a rear wheel, the system comprising front braking means having a friction surface for applying a braking torque to the front wheel, rear braking means for applying a braking torque to the rear wheel, brake torque proportioning means for controlling a ratio of braking torque of the rear wheel relative to the braking torque of the front wheel, brake temperature determining means for determining a temperature of said friction surface of the front braking means, cornering detection means for detecting cornering of the vehicle incorporating the braking system, and control means arranged to increase the ratio of braking torque applied to the rear wheel in response to an increase in said temperature of said friction surface when the vehicle is traveling straight ahead, but to at least partially override said increase of the ratio of braking torque applied to the rear wheel if cornering of the vehicle is detected, wherein the brake temperature determining means is arranged to monitor at least one parameter indicative of the operation of the vehicle and to estimate said temperature from said at least one parameter.

2. The system according to claim 1, wherein said at least one parameter includes the speed of at least one wheel of the vehicle.

3. The system according to claim 2, wherein said at least one parameter includes an indicator of the braking torque applied to at least one wheel of the vehicle.

4. The system according to claim 1, wherein the control means is arranged to control the proportion of torque applied to the rear wheels by controlling a level of slip of the rear wheels and to increase the proportion of braking torque applied to the rear wheels by increasing said level of slip.

5. The system according to claim 1, wherein said at least one parameter includes-an indicator of the braking torque applied to at least one wheel of the vehicle.

6. A braking system for a vehicle having a front wheel and a rear wheel, the system comprising a front brake, having a friction surface, for applying a braking torque to the front wheel, rear brake for applying a braking torque to the rear wheel, a modulator for controlling a ratio of braking torque applied to the rear wheel relative to the braking torque applied to the front wheel, a cornering sensor for detecting cornering of the vehicle incorporating the braking system, and a controller arranged to monitor at least one parameter indicative of the operation of the vehicle and to estimate the temperature of said friction surface from said at least one parameter, and to increase the ratio of braking torque applied to the rear wheel in response to an increase in said temperature of said friction surface when the vehicle is traveling straight ahead, but to at least partially override said increase of the ratio of braking torque applied to the rear wheel if cornering of the vehicle is detected.

7. A braking system for a vehicle having a front wheel and a rear wheel, the system comprising at least one front brake which includes a friction surface for applying a braking torque to the front wheel, a rear brake for applying a braking torque to the rear wheel;

a brake torque proportioning device for controlling a ratio of braking torque applied to the rear wheel and a ratio of the braking torque applied to the front wheel;

a brake temperature determining device for determining a temperature of the friction surface of the front brake;

a cornering detection device for detecting cornering of the vehicle incorporating the braking system; and

a control device for increasing the proportion of braking torque applied to the rear wheel in response to an increase in the temperature of the friction surface of the front wheel when the vehicle is traveling straight ahead, but to at least partially override the increase of the proportion of braking torque applied to the rear wheel if cornering of the vehicle is detected;

wherein the brake temperature determining device monitors at least one parameter indicative of operation of the vehicle and estimates the temperature of the friction surface of the front wheel from the at least one parameter.