Dynamic Modeling of a Variable Displacement Vane Pump Within an Engine Oil Circuit

Automakers and the car-buying public maintain a strong and continuing interest in enhanced vehicle efficiency. Ideally, adaptively controlled oil pumps supply only enough flow within an engine to satisfy its performance requirements. Any extra flow wastes energy. In order to better understand how to improve engine and engine oil circuit efficiency, and to assess pump stability, a detailed dynamic model of a variable displacement vane pump (VDVP) is developed. This detailed pump model is mated to a simplified engine oil circuit model. This marriage allows for a detailed prediction of pump response under various simulated engine operating conditions. The VDVP modeled here adapts its pump chamber volumes according to 1) the feedback oil pressure provided from the engine oil circuit and 2) according to the sizing and installed compression loading of an internal spring. Many phenomena such as internal leakage from one pump chamber volume to another, variable oil conditions such as aeration and viscosity, as well as variations in choice for the internal spring rate and preload can be investigated for their effects on oil pump behavior and performance within the simplified oil circuit.