Patent ID: 7546831

Claim:
A fuel injection apparatus for engines, the apparatus comprising a controller that controls fuel being supplied to and discharged from a plurality of high pressure fuel pumps and a common rail connected to the high pressure fuel pumps to receive pressurized fuel discharged from the high pressure fuel pumps and to inject the fuel into an engine through injection valves between the common rail and the engine, each high pressure fuel pump including: a plunger barrel with a plunger room having a single fuel passage that provides the only connection between the plunger room and a fuel line, the single fuel passage having an electromagnetic valve that must be open to permit fuel to pass between the plunger room and the fuel line such that the electromagnetic valve prevents any fuel from passing between the plunger room and the fuel line when the electromagnetic valve is closed; a plunger driven by a fuel cam to reciprocate in the plunger barrel; and a discharge passage that discharges fuel compressed by the plunger being driven by the fuel cam in a compression stroke to the common rail from the plunger room when a predetermined fuel pressure inside the plunger room is reached, wherein the controller controls the closing of the electromagnetic valve in the single fuel passage to occur during the compression stroke of the plunger and keeps the electromagnetic valve in the single passage closed to prevent any fuel from passing between the plunger room and the fuel line for a period after the plunger has completed the compression stroke and has entered into a decompression stroke that moves the plunger in a direction opposite to that moved during the compression stroke, then the controller opens the electromagnetic valve to allow the plunger room to be communicated with the fuel line through the single fuel passage.