Design And Function: Control

Courtesy of VOLVO CARS CORPORATION

Depending on engine temperature, engine speed (rpm) and torque output the oil pump is controlled to a current optimal pressure. Thereby, the power consumption from the oil pump can decrease, which eventually contributes to a reduction of fuel consumption and exhaust emissions. No control takes place at oil temperatures below 20 °C.

1. <10 Nm
2. 10-100 Nm
3. 100-150 Nm
4. 150-200 Nm
5. >200 Nm
6. Engine speed
7. Oil pressure (bar)

Solenoid 

Regulation of the outer ring is controlled by the engine control module (ECM) via a solenoid that is located in the oil pump housing. By controlling the flow of oil, the adjustment ring can be rotated, which changes the eccentricity and thus the vane pump's supply volume. The solenoid is controlled continuously via a PWM signal, where a fully regulated solenoid means a reduced displacement and an oil pressure of about 1.5 bar, while a solenoid in its second outer position provides a high displacement and an oil pressure of about 4.5 bar. If oil pump regulation should malfunction and the solenoid loses power, there is a safety system with a conventional ball and spring that regulates the oil pressure to a maximum of 6 bar.