The gasoline engine in the intake manifold can produce a higher vacuum pressure, while the diesel engine and the gasoline direct injection engine need to install vacuum pump to provide the vaccum source to meet the vacuum booster braking system requirements.
Vacuum Booster Braking system
The braking system of passenger car and light commercial vehicle mainly uses hydraulic as transmission medium, and it needs to assist the driver to brake when compared with the pneumatic braking system which can provide power source. Vacuum braking power system, also known as vacuum servo braking system, servo braking system on the basis of human hydraulic braking to add a set of other energy to provide braking power booster device, so that the manpower and power can be used, that is, the use of human and engine dynamics as braking energy braking system. Under normal circumstances, the output work pressure is mainly generated by the power servo system, so that the power servo system can still produce a certain degree of braking force by the manpower-driven hydraulic system.
As shown in Fig. 1, the vacuum-assisted (direct-acting) servo braking system diagram of a car it uses the left front wheel brake oil cylinder and right rear wheel brake oil cylinder for a hydraulic circuit, right front wheel brake oil cylinder and left rear wheel brake oil cylinder for another hydraulic circuit layout, that is diagonal layout of double loop hydraulic braking system. The vacuum booster of the vacuum booster chamber and the control valve combine to produce the thrust at work, as well as the pedal force acting directly on the piston rod of the main cylinder of the brake.