Accumulator fuel injection system

An accumulator fuel injection apparatus comprising:

• a first accumulating chamber storing therein fuel under a first pressure;
• a plurality of fuel injectors communicating with the first accumulating chamber for injecting the fuel within the first accumulating chamber into engine cylinders of an engine;
• a drain passage for draining the fuel stored with the first accumulating chamber;
• a second accumulating chamber disposed within the drain passage;
• and
• pressure regulating means for regulating a pressure of the fuel drained through the drain passage to the second accumulating chamber to a second pressure being lower than the first pressure.

An accumulator fuel injection apparatus comprising:

• a first accumulating chamber storing therein fuel under a first pressure;
• a plurality of fuel injectors communicating with the first accumulating chamber for injecting the fuel within the first accumulating chamber into engine cylinders of an engine;
• first means for determining whether a given pressure dropping condition for dropping a pressure of the fuel stored within the first accumulating chamber is met, when the given pressure dropping condition is met, the first means provides a release signal;
• second means, responsive to the release signal from the first means, for draining the fuel stored within the first accumulating chamber while regulating the pressure thereof to a second pressure being lower than the first pressure;
• and
• a drain passage draining the fuel stored within the first accumulating chamber,
• wherein the second means includes a solenoid valve disposed within the drain passage.

A pressure control apparatus for use in an accumulator fuel injection apparatus including an accumulating chamber storing therein fuel under a given pressure and an electrically controlled fuel injector for injecting the fuel in the accumulating chamber into an engine cylinder, comprising:

• a control port having formed thereon a valve seat, communicating with the accumulating chamber through a drain passage for draining the fuel within the accumulating chamber;
• a valve selectively brought into engagement with and disengagement from the valve seat of the control port to open and close the drain passage;
• a valve spring urging the valve into engagement with the valve seat of the control port;
• a solenoid moving the valve out of engagement with the valve seat of the control port when the solenoid is turned on;
• a cylinder formed in the valve having a diameter smaller than that of the valve seat of the control port;
• a balance rod slidably disposed within the cylinder in liquid-tight relationship therewith;
• a balance pressure chamber defined with the cylinder by the balance rod;
• and
• a passage formed in the valve communicating between the control port and the balance pressure chamber at all times.

An accumulator fuel injection apparatus comprising:

• a first accumulating chamber storing therein fuel under a first pressure;
• a fuel injector communicating with the first accumulating chamber;
• a control circuit providing a control signal to the fuel injector to inject part of the fuel stored within the first accumulating chamber into an engine;
• a second accumulating chamber;
• a drain passage communicating the first accumulating chamber with the second accumulating chamber for draining the fuel from the first accumulating chamber to the second accumulating chamber;
• a valve to selectively establish and block communication between the first accumulating chamber and the second accumulating chamber;
• and
• a pressure regulator to regulate a pressure of the fuel stored within the second accumulating chamber to a second pressure being smaller than the first pressure.