BRAKING FORCE CONTROL SYSTEM FOR VEHICLES

• US 20080007115A1
• Filed: 06/29/2005
• Published: 01/10/2008
• Est. Priority Date: 07/08/2004
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Mizutani, Yasuji
• Granted Patent: US 8,210,620 B2
• Time in Patent Office: Days
• US Class Current: 303/113.2
• CPC Class Codes: B60T 2201/03 Brake assistants
• 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 8/17616 Microprocessor-based systems
• 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 8/3275 Systems with a braking assistant function, i.e. automatic full braking initiation in dependence of brake pedal velocity

Abstract

According to the braking force control system of the present invention it is prevented that the the braking root pressure is increased unnecessarily high when the braking force increase suppressing control was initiated during the execution of the brake assist control without losing the effects of increasing the braking force available when the brake assist control only is executed. When the brake assist control is initiated, the pressure increase Pcf, Pcr of the braking root pressure of the front and rear wheels is increased relative to the master cylinder pressure Pm, but when the anti-skid control is executed for the left and right of the front or rear wheels, when the anti-skid control is executed for one of the front left and right wheels, while a yaw behavior control is executed for the other of the front left and right wheels, or when a braking force front/rear distribution control is executed, during the execution of the anti-skid control, the increase of the braking root pressure for the front or rear wheels is suppressed.

Claims

1. A braking force control system for vehicles adapted to execute a braking force increasing control for increasing the braking force relative to the braking force corresponding to the braking operation by the driver by increasing the braking pressure when the braking operation was made quickly by the driver, and to execute a braking force increase suppressing control for suppressing the increase of the braking force of a selected wheel or wheels when the vehicle is in a determined running condition, comprising:

control valves provided for the respective wheels to adjust the braking pressure of the respective wheels,

braking root pressure control portions to increase or decrease the braking root pressures supplied to the respective control valves,

a judging portion to judge an initiation or a high probability thereof of the braking force increase suppressing control, and

a braking root pressure increase suppressing portion to suppress the increase of the braking root pressure when the initiation or a high probability thereof of the braking force increase suppressing control was judged by the judging portion during the braking force increasing control as compared to when the initiation or a high probability thereof of the braking force increase suppressing control is not judged.

2. A braking force control system for vehicles according to claim 1, wherein the braking force increase suppressing control is an anti-skid control.

3. A braking force control system for vehicles according to claim 1 or 2, wherein the braking root pressure increase suppressing portion is a braking root pressure increasing gradient decreasing portion for decreasing the increasing gradient of the braking root pressure.

4. A braking force control system for vehicles according to claim 3, wherein the braking root pressure increasing gradient decreasing portion decreases the increasing gradient of the braking root pressure of the left and right wheels when an initiation or a high probability thereof of the anti-skid control for the left and right wheels was judged.

5. A braking force control system for vehicles according to claim 3, wherein when an initiation or a high probability thereof of an anti-skid control with respect to one of the front left and front right wheels was judged and an initiation or a high probability thereof of a yaw behavior control with respect to the other of the front left and front right wheels for suppressing an increase of the difference between the braking forces of the front left and front right wheels was also judged, the braking root pressure increasing gradient decreasing portion decreases the increase gradient of the braking root pressure of at least the other of the front left and front right wheels.

6. A braking force control system for vehicles according to claim 1 or 2, wherein, when the braking force increasing control is executed, the braking root pressure control portion increases the braking root pressure up to a determined final target pressure, while the braking root pressure increase suppressing portion is a target braking root pressure decreasing portion which suppresses the increase of the braking root pressure by decreasing the final target pressure of the braking root pressure.

7. A braking force control system for vehicles according to claim 6, wherein, when an initiation or a high probability thereof of the anti-skid control with respect to the left and right wheels was judged, the target braking root pressure decreasing portion decreases the target pressure of the braking root pressure.

8. A braking force control system for vehicles according to claim 6, wherein, when an initiation or a high probability thereof of the anti-skid control with respect to one of the front left and front right wheels was judged and an initiation or a high probability thereof of a yaw behavior control with respect to the other of the front left and front right wheels for suppressing an increase of the difference of the braking forces of the front left and front right wheels was judged, the target braking root pressure decreasing portion decreases the final target pressure of the braking root pressure of at least the other front wheel.

9. A braking force control system for vehicles according to claim 1, wherein the judging portion judges to initiate the braking force increase suppressing control when a condition for initiating the braking force increase suppressing control was fulfilled.

10. A braking force control system for vehicles according to claim 1, wherein the judging portion judges that the probability of initiation of the braking force increase suppressing control is high when the total increasing amount of the braking root pressure by the braking force increasing control has exceeded a standard value.

11. A braking force control system for vehicles according to claim 1, wherein the judging portion judges that the probability of initiation of the braking force increase suppressing control is high when the consecutive time of increase of the braking root pressure by the braking force increasing control has exceeded a standard time.

12. A braking force control system for vehicles according to claim 1, wherein the braking force increase suppressing control is a control for suppressing the increase of the braking force of the rear wheels by a front/rear distribution control of the braking force.