Patent ID: 7234448

Claim:
A fuel injection pump comprising: a camshaft driven by an internal combustion engine to rotate; a cam rotating with the camshaft; a cam ring revolving around the camshaft so that the cam ring rotates with respect to the cam along an outer periphery of the cam; a housing for rotatably housing the camshaft, the housing being formed with a fuel pressurizing chamber; a plunger, which reciprocates in accordance with the revolution of the cam ring to pressurize and pressure-feed fuel drawn into the fuel pressurizing chamber; and a rotary pump rotated by the camshaft for supplying the fuel, which is drawn into the fuel pressurizing chamber, wherein the housing includes a first housing portion for rotatably housing the camshaft, the cam ring and the rotary pump, and a second housing portion for housing the plunger so that the plunger can reciprocate, the first housing portion is formed with a first low-pressure fuel passage for streaming low-pressure fuel from the rotary pump toward the fuel pressurizing chamber, the second housing portion is formed with a second low-pressure fuel passage connected to the fuel pressurizing chamber, and the fuel injection pump further comprises a filter disposed downstream of the rotary pump in one of an outlet portion of the first low-pressure fuel passage, an inlet portion of the second low-pressure fuel passage facing the outlet portion of the first low-pressure fuel passage, and a certain point in the second low-pressure fuel passage.