Hydraulic System
Hydraulic System Hydraulically operated power assisted systems work on either a constant pressure or constant flow layout. The former incorporates a hydraulic accumulator to store the pressure. The latter uses flow of fluid around the system continuously until assistance is required. The Components. The essential components required to operate a constant flow system are shown in Fig. 27.64. The system incorporates a pump, control valve and ram cylinder in addition to the normal steering components. Pump. An eccentric rotor pump driven by a vee belt from the engine crankshaft is normally used. The pump is located either on the front of the engine or at the front of the crankshaft. A fluid reservoir is attached to the pump and generally stores a low-viscosity mineral oil similar to the type used in an automatic transmission. A pressure relief valve limits the maximum pressure of 7 MN/m2, and once this pressure is attained the oil passes from the pump outlet back to the reservoir. Control