Cylinder injection high-pressure fuel pump

摘要

A cylinder injection high-pressure fuel pump permits reduction in size and cost thereof and it is also capable of securely absorbing high-frequency pulsations. The cylinder injection high-pressure fuel pump (200) has: a casing (1) in which an inlet passage (2) for taking fuel in and a discharge passage (35) for discharging the fuel are formed; a cylinder (30) formed in the casing (1); a fuel pressurizing chamber (32) formed in a part of the cylinder (30); and a plunger (31) disposed in the cylinder (30) such that it may reciprocate therein. As the plunger (31) reciprocates, the fuel is taken into the fuel pressurizing chamber (32) through the inlet passage (2) and pressurized therein, then the pressurized fuel is discharged through the discharge passage (35) and forcibly fed into a fuel injector of a cylinder injection type engine. The high-pressure fuel pump (200) is equipped with: a capacity chamber (44) formed by enlarging a part of the inlet passage (2); and a sealed vessel (42) which is disposed in the capacity chamber (44), which has a gas hermetically sealed therein, and which changes the volume thereof according to a change in the pressure of the capacity chamber (44).