Camshaft Retard Control - Volvo B5254T3 Manual

Camshaft Retard Control

The oil is forced from the engine's lubricating system (C).
The position of the valve is controlled by the ECM and oil flows via the vents in the piston into the valve
i n the camshaft oil duct (B).
Chamber B1 fills with oil. Due to the oil pressure in the chamber, the rotor rotates clockwise.
The rotor wing (4) reaches its limit position and the lock pin is pushed out into a hole on the inside of the
front of the timing belt pulley.
Return oil flows from chamber A1 via the camshaft valve and back to the oil pan.
This process takes place very rapidly. The reset valve is controlled by the ECM for advancing and
retarding at a very high frequency which allows for quick and exact control.
The amount to which the camshaft can be advanced (change in the radial position of the camshaft)
varies by engine variant.