HIGH-PRESSURE FUEL PUMP

摘要

A high pressure fuel pump includes a cylinder having a pressurizing chamber and a plunger inserted into the cylinder. The plunger is axially reciprocated by a lifter to pressurize fuel in the pressurizing chamber. A seal member encompasses a portion of the plunger that is projected from the cylinder. The seal member disconnects a cylinder side space surrounded by the seal member from a lifter side space outside the seal member. The seal member has an annular lip portion that contacts a peripheral surface of the plunger, and the annular lip portion has a pair of lips separated from each other in an axial direction of the plunger. An axial distance between the lips is greater than a stroke of the plunger. As a result, fuel does not enter the lifter side space, and lubricating oil does not enter the cylinder side space.