| 摘要 |
PROBLEM TO BE SOLVED: To suppress useless energy for driving a pump and shortening of a pump life, in a brake system for a vehicle including a brake cylinder operated depending on hydraulic pressure of a hydraulic power source. SOLUTION: The hydraulic pressure of the power source including a pump and an accumulator is controlled to generate booster pressure in a booster chamber of a master cylinder with a hydraulic booster, pedaling force is boosted up thereby and a rear wheel brake is actuated, and a front wheel brake is actuated by the hydraulic pressure generated in a pressurization chamber of the master cylinder. An operation of the pump is started by actuating a brake pedal when a voltage of a battery is lowered (S57), upper limit pressure and lower limit pressure of a hydraulic fluid stored in the accumulator are heightened when a temperature of the hydraulic fluid is low, when a brake system is failured, or when fading or a carrying load is large (S54, S63, S71, S73), and control responsiveness for the brake is enhanced thereby to cope with increasing requirment for braking force. Augmentation for the operation of the pump is acceptable when the brake system is failured or likely, in an hydraulic power source including no accumulator. |
