Apparatus for feeding high-pressure fuel into engine cylinder for injection control

An apparatus for injecting a high-pressure fuel into each cylinder of an engine, comprising:

• a booster pump apparatus including a cylinder chamber, a piston movably located in the cylinder chamber to divide the cylinder chamber into first and second fuel chambers, so that the pressure-receiving area of the piston facing the first fuel chamber is greater than that facing the second fuel chamber, a first check valve located in a first fuel passage connecting with the first fuel chamber in the cylinder chamber, so that the high-pressure fuel is fed into the first fuel chamber through the first check valve, a second check valve located in a second fuel passage connecting with the second fuel chamber, a third check valve located in a third fuel passage connecting the first and second fuel chambers, whereby the fuel is allowed to flow only from the first fuel chamber to the second fuel chamber, and a first piezoelectric device adapted to be extended when a voltage is applied thereto and contracted when the applied voltage drops, so that the piston is moved toward the first fuel chamber when the piezoelectric device is extended, and that the piston is moved toward the second fuel chamber by the pressure inside the first fuel chamber when the piezoelectric device is contracted, whereby the high-pressure fuel fed into the first fuel chamber is delivered, under a further increased pressure, from the second fuel chamber via the second check valve when the piston moves toward the second fuel chamber as the first piezoelectric device is contracted;
• a fuel injection valve adapted to inject the fuel into the engine cylinder and to be supplied with the high-pressure fuel from the second fuel chamber through the second check valve, so that fuel injection is executed as the high-pressure fuel is supplied;
• a second piezoelectric device facing a combustion chamber in the engine cylinder and adapted to be subjected to a pressure produced during an explosion process of the combustion chamber, so that high-voltage power is generated in the second piezoelectric device and supplied to the first piezoelectric device, thereby extending the first piezoelectric device;
• and
• discharge control means for discharging, in response to a fuel injection timing, the high voltage applied to the first piezoelectric device, thereby contracting the piezoelectric device.

An apparatus for feeding high-pressure fuel into an engine cylinder for injection control, comprising:

• a cylinder chamber;
• a piston movably located in the cylinder chamber to divide the cylinder chamber into first and second fuel chambers, so that the pressure-receiving area of the piston facing the first fuel chamber is greater than that facing the second fuel chamber;
• a first check valve located in a first fuel passage connecting with the first fuel chamber in the cylinder chamber, so that the high-pressure fuel is fed into the first fuel chamber through the first check valve;
• a second check valve located in a second fuel passage connecting with the second fuel chamber, said second check valve defining an output fuel passage through which the fuel forced out of the second fuel passage is delivered as a high-pressure output fuel;
• a fuel injection valve adapted to inject the fuel into the engine cylinder and to be supplied with the high-pressure output fuel from the second fuel passage;
• a third check valve located in a third fuel passage connecting the first and second fuel chambers, whereby the fuel is allowed to flow only from the first fuel chamber to the second fuel chamber;
• a piezoelectric device adapted to be extended when a voltage is applied thereto and contracted when the applied voltage drops, so that the piston is moved toward the first fuel chamber when the piezoelectric device is extended, and that the piston is moved toward the second fuel chamber by the pressure inside the first fuel chamber when the piezoelectric device is contracted;
• and
• control means for lowering, in response to a fluid output instruction, the voltage applied to the piezoelectric device;
• said cylinder chamber including a first cylinder portion, and a second cylinder portion coaxial and continuous with the first cylinder portion and having an inside diameter sufficiently smaller than that of the first cylinder portion, and said piston including a first piston member movable in the first cylinder portion along the axis thereof, and a second piston member integral and coaxial with the first piston member and movable in the second cylinder portion.