5.1. General information

For reduction of the effort enclosed to a steering wheel for its turn to cars establish the hydraulic amplifier of steering. As additional force the liquid which is under high pressure which moves in the working cylinders located on the steering mechanism is used. The distributive valve serves for forcing in the power cylinder of liquid under pressure which corresponds to an angle of rotation of a steering wheel. Distributive valves work according to the so-called principle of the open center i.e. when the distributive valve does not operate, the liquid given by the pump is bypassed back in a tank with a zero pressure. Pressure in hydraulic system is created by the pump put in action by a belt from a pulley of a bent shaft of the engine.
The steering mechanism is connected to a steering shaft through an intermediate shaft.

At violation of operation of the electroamplifier of steering on the display of the on-board computer the following warning messages are displayed:

– "Direction a controler" – check steering), "Service" accompanied with fire by constant light of an alarm lamp;
– "Direction defaillanbe" – malfunction of steering), "Stop" accompanied with fire by constant light of an alarm lamp;
– fire by the blinking light (with a frequency of 8 Hz) an alarm lamp of "Service" indicates that the angle of rotation of a steering wheel is not calibrated (EBU is not programmed).

At diagnostics the alarm lamp of "Service" blinks with a frequency of 2 Hz.

Fig. 5.1. Mechanism of the hydraulic booster of steering of the Megane II car: 1 – EBU of the electroamplifier of steering with the sensor of torque and an angle of rotation; 2 – the step electric motor with a worm reducer; 3 – reducer gear wheel; 4 – intermediate shaft of system of steering; 5 – a fork of the cardan hinge of a shaft of steering in salon

Fig. 5.2. EBU of system of the helmsman management with the electric hydraulic booster