Theoretical study on performance characteristics of a variable displacement vane pump according to a variable amount occurrence

Theoretical studies were performed to understand the variation of performance of a variable displacement vane pump with automatic transmission according to the operating conditions and variable parameters. Chamber volume, discharge flow, pressure ripples, and cavitation occurrence were analyzed with variable amounts. The analysis result indicated that the discharge flow rate and pressure ripples increased with a rise of rotational speed, but decreased with variable amount increases. Increase of the oil temperature caused a slight decrease of the discharge flow and the driving torque. Cavitation definitely appeared at low temperatures and high rotational speeds, but it dramatically decreased with variable amount increases. The driving torque increased proportionally with the rotational speed and decreased with oil temperature. The maximum total efficiency was 73.8% at an oil temperature of 80 degrees C but it decreased by 3.5% at 120 degrees C.