Volumetric Efficiency Based Lift Pump Control

摘要

As one example, a method of operating a fuel delivery system of a directly injected internal combustion engine including a plurality of in-cylinder direct fuel injectors, a higher pressure fuel pump and a lower pressure fuel pump is provided. The method comprises operating the lower pressure fuel pump and the higher pressure fuel pump to maintain a prescribed fuel pressure at the fuel injectors; and varying an amount of pump work that is provided by the lower pressure fuel pump relative to the higher pressure fuel pump responsive to an indication of the efficiency of the higher pressure pump.