Patent ID: 7490592

Claim:
A fuel injection apparatus for engines comprising a plurality of high pressure fuel pumps in each of which fuel supplied to a plunger room is compressed by a plunger driven by a fuel cam to reciprocate in a plunger barrel, the compressed fuel being discharged to a common rail at timing controlled by an electromagnetic valve, high pressure fuel accumulated in the common rail being injected into cylinders of an engine through injection valves at controlled timing, wherein a controller is provided which allows some of the plurality of high pressure fuel pumps to be made inoperative in discharging fuel to the common rail by controlling the electromagnetic valves of said some of the pumps so that the plunger rooms of said some of the pumps are communicated to a fuel feed line for feeding fuel to the plurality of the pumps when the engine is operated with small/medium fuel injection quantity of smaller than a certain quantity, and further wherein when the engine is operated under low/medium engine loads, some of the plurality of high pressure fuel pumps are made inoperative in accordance with a result of a calculation of a number of the high pressure fuel pumps needed for injecting the fuel injection quantity corresponding to said low/medium engine loads.