Brake hydraulic pressure control device for vehicle

Patent metadata

Field	Value
Publication number	US-9604612-B2
Application number	US-201214346455-A
Country	US
Kind code	B2
Filing date	Sep 27, 2012
Priority date	Sep 28, 2011
Publication date	Mar 28, 2017
Grant date	Mar 28, 2017

Abstract

A brake hydraulic pressure control device for a vehicle in which operation of a hydraulic pressure adjustment unit that can carry out adjustment involving individually increasing/decreasing brake hydraulic pressures applied to wheel brakes for front and rear wheels is controlled for allowing differential pressure between brake hydraulic pressures of the left and right wheel brakes, wherein allowable differential pressure setting means is arranged for setting the allowable differential pressure corresponding to the coefficient of friction of a road surface, hydraulic pressure acquisition means acquires a lock hydraulic pressure, which is a hydraulic pressure when starting anti-lock brake control for the respective wheel brake, and when the lock hydraulic pressure of the wheel brakes for the front wheels acquired by the hydraulic pressure acquisition means is no greater than a predetermined value, application of the allowable differential pressure corresponding to the coefficient of friction of the road surface is prohibited.

First claim

The invention claimed is:

1. A brake hydraulic pressure control device for a vehicle, the control device comprising:
an anti-lock hydraulic pressure adjustment unit that is configured to carry out adjustment involving individually adjusted brake hydraulic pressures applied to wheel brakes for front wheels and wheel brakes for rear wheels of the vehicle, in order to prevent the front wheels and the rear wheels from attaining a locked state when braking;
allowable differential pressure setting means that sets a first allowable differential pressure between the brake hydraulic pressures of the wheel brakes for the left and right front wheels and a second allowable differential pressure between the brake hydraulic pressures of the wheel brakes for the left and right rear wheels, operation of the anti-lock hydraulic pressure adjustment unit being controlled so that a maximum applied differential pressure between brake hydraulic pressures of the left and right wheel brakes for at least one of the front wheels and the rear wheels is no greater than the first or second allowable differential pressure that is set by the allowable differential pressure setting means; and
hydraulic pressure acquisition means that acquires a lock hydraulic pressure, which is a hydraulic pressure sensed by a pressure sensor when starting anti-lock brake control for a respective wheel brake,
wherein the allowable differential pressure setting means sets the first and second allowable differential pressures by selecting a maximum among three components including a vehicle body speed component, determined according to an estimated vehicle body speed, a lateral acceleration component determined according to a lateral acceleration sensed by a lateral acceleration sensor, and a coefficient of friction component determined according to a coefficient of friction of a road surface on which the vehicle is traveling, the coefficient of friction determined based on sensed values of the lock hydraulic pressures of the wheel brakes for the front wheels,
wherein during normal operating conditions, the allowable differential pressure setting means selectively sets the first allowable differential pressure so as to correspond to a coefficient of friction of the road surface on which the vehicle is traveling, and
wherein, during low-friction conditions, when the lock hydraulic pressure of either of the wheel brakes for the front wheels acquired by the hydraulic pressure acquisition means is no greater than a predetermined value which corresponds to a low coefficient of friction, the allowable differential pressure setting means sets the first allowable differential pressure by selecting a larger value between the vehicle body speed component and the lateral acceleration component.

2. The brake hydraulic pressure control device for a vehicle according to claim 1 , wherein when the lock hydraulic pressure of the wheel brake for either one of the left and right front wheels acquired by the hydraulic pressure acquisition means is no greater than the predetermined value, the allowable differential pressure setting means is prohibited from setting said first allowable differential pressure to correspond to the coefficient of friction of the road surface.

3. The brake hydraulic pressure control device for a vehicle according to claim 1 , wherein the allowable differential pressure setting means is prohibited from setting said first or second allowable differential pressure to correspond to the coefficient of friction of the road surface at least to the wheel brakes for the rear wheels based on the lock hydraulic pressures of the wheel brakes for the front wheels acquired by the hydraulic pressure acquisition means.

4. The brake hydraulic pressure control device for a vehicle according to claim 1 , wherein the hydraulic pressure acquisition means starts acquisition of lock hydraulic pressure when starting to increase pressure in a first cycle of an anti-lock brake control operation.

5. A brake hydraulic pressure control device for a vehicle, the control device comprising:
an anti-lock hydraulic pressure adjustment unit that is configured to carry out adjustment involving individually adjusted brake hydraulic pressures applied to wheel brakes for front wheels and wheel brakes for rear wheels in order to prevent the front wheels and the rear wheels from attaining a locked state when braking;
allowable differential pressure setting means that sets a first allowable differential pressure between the brake hydraulic pressures of the wheel brakes for the left and right front wheels and a second allowable differential pressure between the brake hydraulic pressures of the wheel brakes for the left and right rear wheels, operation of the anti-lock hydraulic pressure adjustment unit being controlled so that a maximum applied differential pressure between brake hydraulic pressures of the left and right wheel brakes for at least one of the front wheels and the rear wheels is no greater than the first or second allowable differential pressure that is set by the allowable differential pressure setting means; and
hydraulic pressure acquisition means that acquires a lock hydraulic pressure, which is a hydraulic pressure sensed by a pressure sensor when starting anti-lock brake control for a respective wheel brake,
wherein the allowable differential pressure setting means sets the first and second allowable differential pressures by selecting a maximum among three components including a vehicle body speed component, determined according to an estimated vehicle body speed, a lateral acceleration component determined according to a lateral acceleration sensed by a lateral acceleration sensor, and a coefficient of friction component determined according to a coefficient of friction of a road surface on which the vehicle is traveling, the coefficient of friction determined based on sensed values of the lock hydraulic pressures of the wheel brakes for the front wheels,
wherein during normal operating conditions, the allowable differential pressure setting means selectively sets the first allowable differential pressure so as to correspond to a coefficient of friction of a road surface on which the vehicle is traveling, and
wherein, during low-friction conditions, when the lock hydraulic pressure of either of the wheel brakes for the front wheels acquired by the hydraulic pressure acquisition means is no greater than a predetermined value which corresponds to a low coefficient of friction, the allowable differential pressure setting means sets the first allowable differential pressure by selecting a larger value between the vehicle body speed component and the lateral acceleration component,
and wherein said allowable differential pressure setting means includes a map which stores preset allowable differential pressure between the brake hydraulic pressures of the wheel brakes for the left and right front wheels and between the brake hydraulic pressures of the wheel brakes for the left and right rear wheels based on estimated vehicle body speed.

6. The brake hydraulic pressure control device for a vehicle according to claim 5 , wherein when the lock hydraulic pressure of the wheel brake for either one of the left and right front wheels acquired by the hydraulic pressure acquisition means is no greater than the predetermined value, the allowable differential pressure setting means is prohibited from setting said first allowable differential pressure to correspond to the coefficient of friction of the road surface.

7. The brake hydraulic pressure control device for a vehicle according to claim 5 , wherein the allowable differential pressure setting means is prohibited from setting said first or second allowable differential pressure to correspond to the coefficient

Assignees

• Nissin Kogyo Kk
• Honda Motor Co Ltd
• Autoliv Nissin Brake Systems Japan Co Ltd

Inventors

• Sekiya Tomoaki
• Honda Shigehiro
• Ueda Ryosuke

Classifications

• B60T8/1764 Primary

  Regulation during travel on surface with different coefficients of friction, e.g. between left and right sides, mu-split {or between front and rear} · CPC title

• B60T8/17636 Primary

  Microprocessor-based systems · CPC title