9-3 Hatchback (9400) L4-2.0L Turbo (B205) (2000)
/l4-2.0l_turbo_(b205)/Page-2036002.png)
The control valve regulates a constant flow from the pump irrespective of the engine/pump speed.
One side of the control valve is in direct contact with the delivery side of the pump (A). The outlet (B) from the pump incorporates a restriction from
which a connecting line (1) leads to the other side of the valve, which is fitted with a spring (2). When not actuated, the valve is pressed against the
outlet side.
Inside the control valve there is an overflow valve (3), which is affected by the hydraulic pressure on the spring side of the control valve at high
pressure.
A certain amount of hydraulic fluid must pass through the valves (A) and (C) for the control valve to be able to operate, but not when the steering
wheel is at full lock. The pump delivers a maximum pressure of approximately 10 MPa (100 bar) and a maximum flow of approximately 6 liters per
minute.
Steering and parking at low engine speed
The pressure delivered by the pump (shaded portion) is reduced slightly by the restriction in the pump outlet.
This reduced pressure is lead to the spring side of the control valve, creating a slight pressure difference between the two sides of the valve. Owing to
the low pump speed, however, the difference in pressure is not sufficient to actuate the valve.
Steering at high engine speed (pump in flow control mode)
