Brake control apparatus
AssigneeAdvics Co., Ltd.
InventorMototsugu Sawada
Life of this patent
Estimating the term…
Abstract
An object of the invention is to reduce an influence of deviation in pressure increasing performance, which would be caused by individual differences of pressure increase valves, so that a desired braking force may be obtained. A moderate pressure increasing operation is carried out for wheel cylinder pressure of a wheel, which is on a high μ-road, wherein a demand differential pressure for a pressure increase valve is set at a first target pressure for a first time period and then switched to a second target pressure for a second time period. The influence of the deviation may be absorbed during the moderate pressure increasing operation, so that a difference of wheel cylinder pressure between front left and front right wheels may be reduced.
Claims3
A brake control apparatus for a vehicle, comprising:
- a master cylinder supplying brake fluid under pressure to wheel cylinders;
- pressure increase valves connected between the master cylinder and the wheel cylinders for controlling a differential pressure between upstream and downstream sides of the pressure increase valves by linearly controlling power supply amount to corresponding solenoids of the pressure increase valves, the pressure increase valves controlling the differential pressure to increase the brake fluid pressure applied to each wheel cylinder during a braking operation;
- and
- an electronic control unit for controlling each of the pressure increase valves,
- the electronic control unit comprising:
- a power supply amount control portion for controlling the power supply amount to a respective solenoid of a respective pressure increase valve for one wheel cylinder of the wheel cylinders while a pressure increasing operation is carried out for the one wheel cylinder, the power supply amount control portion alternately setting a demand differential pressure for the respective pressure increase valve at a first target pressure and a second target pressure, the second target pressure being higher than the first target pressure, and both the first and second target pressures corresponding to the differential pressure between upstream and downstream sides of the respective pressure increase valve,
- a first differential pressure setting portion for setting the first target pressure by decreasing the first target pressure in a stepwise manner each time when the demand differential pressure is switched from the first target pressure to the second target pressure,
- a second differential pressure setting portion for setting the second target pressure by decreasing that the second target pressure in a stepwise manner each time when the demand differential pressure is switched from the second target pressure to the first target pressure,
- wherein the first differential pressure setting portion decreases the first target pressure with a first predetermined decremental slope, and
- wherein the second differential pressure setting portion decreases the second target pressure with a second predetermined decremental slope, and the second predetermined decremental slope is larger than the first predetermined decremental slope.
Dependencies are inferred from the claim text.