An Analytical and Experimental Study of a High Pressure Single Piston Pump for Gasoline Direct Injection (GDi) Engine Applications

In recent years, gasoline direct injection (GDi) engines have been popular due to their inherent potential for reduction of exhaust emissions and fuel consumption to meet stringent EPA standards. These engines require high-pressure fuel injection in order to improve the atomization process and accelerate mixture preparation. The high-pressure fuel pump is an essential component in the GDi system. Therefore, understanding the flow characteristics of this device and its associated behavior is critical for improving the performance of this category of engines.

In this paper, the fluid flow characteristics in a high-pressure single-piston pump for use in GDi engines are analyzed using 1-D LMS Imagine.Lab AMESim system and 3-D Ansys Fluent computational fluid dynamics (CFD) models. The flow rate of the fuel pump under various cam speeds has been examined along with characteristics of the pump's control valve. A comparison of model predictions with experimentally obtained data shows reasonably good agreement.

Similar analytical techniques may be used in modeling other pump details and may also be extended to adjacent components for simulation of the entire fuel system. Further improvements to the pump model are planned to correlate results more closely with test data with the eventual goal of facilitating pump design activity leading to improvements in pump and overall fuel system performance.