Patent ID: 6971857

Claim:
A fuel injection pump comprising: a housing defining a cam chamber and an orifice; a driving shaft rotating within the housing; a feed pump formed in the housing, wherein the feed pump is driven by the driving shaft to draw fuel and discharge the fuel into a fuel pressurizing chamber; a cam housed within the cam chamber, the cam rotating with the driving shaft; and a plunger, wherein the plunger contacts and follows an outer circumferential surface of the cam and reciprocates to pressurize the fuel drawn into the fuel pressurizing chamber, wherein the orifice allows the cam chamber and a discharge fuel chamber of the feed pump to communicate with each other, wherein the fuel is supplied from the discharge fuel chamber through the orifice to the cam chamber, and wherein an opening of the orifice on the discharge fuel chamber side is formed on the same plane as a wall surface of the discharge fuel chamber.