Direct injection fuel pump

摘要

Methods and systems are provided for a direct injection fuel pump. The methods and system control pressure within a compression chamber so as to improve fuel pump lubrication.

主权项

1. A method, comprising:
while a solenoid activated check valve at an inlet of a direct injection fuel pump is commanded to a pass-through state during a compression stroke in the direct injection fuel pump,
adding a pre-loaded accumulator upstream of the solenoid activated check valve, the pre-loaded accumulator having a substantially constant pressure-volume characteristic, wherein the substantially constant pressure-volume characteristic of the pre-loaded accumulator is provided by a pre-loaded spring coupled to a piston in a bore with stops.