Nowadays most small cars are powered by hydraulic braking, because liquids cannot be compressed, the power of almost 100% transmission, the basic principle is that the driver stepped down the brake pedal, the brake pump in the total pressure on the oil, the liquid will be transferred through the pipeline to each wheel brake caliper piston, the piston drive brake caliper clamping brake disc so that a huge friction force to reduce the vehicle.
We start with the brake master pump, which is usually located in the engine compartment firewall near the driver's side, some of the brake master pumps "poor", and even people suspect whether it provides enough brake force. In fact, there is no need to worry about this, because the brake system uses the "Pascal's Law".
According to the basic equations of hydrostatic pressure (p=p0+ ρ gh), the liquid that is placed in the confined vessel is changed when the pressure p0 of the liquid still keeps its original stationary state unchanged, and the pressure of any point in the liquid will change the same size.
In simple terms, we tread the brake pedal after the pressure on the total pump liquid is equal to the brake force plug in the liquid pressure, but because pressure equals the unit area of pressure, so as long as the increase of the size of the piston, the pressure will increase. For example, the following illustration of the experiment, two cylindrical pistons, the left piston diameter is 2 inches, the right piston diameter is 6 inches, that is, the left of the piston 3 times times, so if the left piston exerts a certain amount of force, then the right piston will produce a 9 times times the Force (area is the square of the radius multiplied by 3.14), which is now all the theoretical basis of hydraulic machinery, so cranes can lift tens of tons of cargo through the hydraulic system.