Power Steering.
Rack and Pinion Type Power steering has hydraulic and electric types. Todays, hydraulic power steering is used on almost all car models . Three major components of the power steering is hydraulic vane pump, control valve and power cylinder. To increase driving comfort, most modern cars use wide tires sized and low pressure, which could increase the surface contact area of wheel-to-street. As a result, the required power steering gets heavier. Power steering can be lowered by lowering the gear ratio steering gear. However, this way will cause rotary motion of the steering wheel when the vehicle becomes more rounded, so it can not do a sharp turn. To maintain steering and agility, at the same time make the power steering remains light, it takes a kind of steering aids. In other words, power steering, which has been widely used for large vehicles, are now also widely used for small passenger cars.