A fuel injection device for smooth discharge of a gas accumulated therein comprising a fuel pump, a solenoid valve for injecting pressurized fuel into the intake passage of an engine, a high-pressure fuel passage extending from the fuel pump to the solenoid valve and has a medially positioned constant-pressure chamber, and a fuel return passage connected to a fuel return pipe, with the fuel return passage extending from the constant-pressure chamber and having a medially positioned priming pump. The constant-pressure chamber is configured with the top wall in the upper space thereof disposed above the opening of the high-pressure fuel passage opposite the solenoid valve, the fuel return passage opens into the upper space at a position above the opening of the high-pressure fuel passage, and the gas accumulating in the constant-pressure chamber is discharged from the upper space toward the fuel tank via the fuel return passage.

A fuel injection device for smooth discharge of a gas accumulated therein comprising a fuel pump, a solenoid valve for injecting pressurized fuel into the intake passage of an engine, a high-pressure fuel passage extending from the fuel pump to the solenoid valve and has a medially positioned constant-pressure chamber, and a fuel return passage connected to a fuel return pipe, with the fuel return passage extending from the constant-pressure chamber and having a medially positioned priming pump. The constant-pressure chamber is configured with the top wall in the upper space thereof disposed above the opening of the high-pressure fuel passage opposite the solenoid valve, the fuel return passage opens into the upper space at a position above the opening of the high-pressure fuel passage, and the gas accumulating in the constant-pressure chamber is discharged from the upper space toward the fuel tank via the fuel return passage.

A manually actuated feed pump is provided with a primer bulb to be manually actuated by an operator. The primer bulb has a pump chamber. A travel-controlled valve connects the pump chamber to a fuel line. The travel-controlled valve has a valve member that is moved by an actuation travel of the primer bulb into an open position that opens the travel-controlled valve. A first spring is operatively connected to the valve member and to the primer bulb. The primer bulb acts through the first spring on the valve member.

A manually actuated feed pump is provided with a primer bulb to be manually actuated by an operator. The primer bulb has a pump chamber. A travel-controlled valve connects the pump chamber to a fuel line. The travel-controlled valve has a valve member that is moved by an actuation travel of the primer bulb into an open position that opens the travel-controlled valve. A first spring is operatively connected to the valve member and to the primer bulb. The primer bulb acts through the first spring on the valve member.

A high pressure pump of a common rail pump system includes a pump body having a cylinder with a piston bore and a piston reciprocally driven in the piston bore to pressurize fuel in the cylinder. The piston has an inner end located in the piston bore and an outer end outside the piston bore. A bellow having a first opening and a second opening is arranged between the piston and the pump body, wherein the piston extends through the first and second openings, wherein the bellow is connected to the pump body such that the first opening is sealed on the pump body and wherein the bellow is connected to the outer end of the piston such that the second opening is sealed on the piston. This arrangement prevents mixing of engine oil and fuel. The bellow may be connected to a drainage line via a one-way valve.

A high pressure pump of a common rail pump system includes a pump body having a cylinder with a piston bore and a piston reciprocally driven in the piston bore to pressurize fuel in the cylinder. The piston has an inner end located in the piston bore and an outer end outside the piston bore. A bellow having a first opening and a second opening is arranged between the piston and the pump body, wherein the piston extends through the first and second openings, wherein the bellow is connected to the pump body such that the first opening is sealed on the pump body and wherein the bellow is connected to the outer end of the piston such that the second opening is sealed on the piston. This arrangement prevents mixing of engine oil and fuel. The bellow may be connected to a drainage line via a one-way valve.

A fuel injection device for smooth discharge of a gas accumulated therein comprising a fuel pump, a solenoid valve for injecting pressurized fuel into the intake passage of an engine, a high-pressure fuel passage extending from the fuel pump to the solenoid valve and has a medially positioned constant-pressure chamber, and a fuel return passage connected to a fuel return pipe, with the fuel return passage extending from the constant-pressure chamber and having a medially positioned priming pump. The constant-pressure chamber is configured with the top wall in the upper space thereof disposed above the opening of the high-pressure fuel passage opposite the solenoid valve, the fuel return passage opens into the upper space at a position above the opening of the high-pressure fuel passage, and the gas accumulating in the constant-pressure chamber is discharged from the upper space toward the fuel tank via the fuel return passage.

A fuel injection device for smooth discharge of a gas accumulated therein comprising a fuel pump, a solenoid valve for injecting pressurized fuel into the intake passage of an engine, a high-pressure fuel passage extending from the fuel pump to the solenoid valve and has a medially positioned constant-pressure chamber, and a fuel return passage connected to a fuel return pipe, with the fuel return passage extending from the constant-pressure chamber and having a medially positioned priming pump. The constant-pressure chamber is configured with the top wall in the upper space thereof disposed above the opening of the high-pressure fuel passage opposite the solenoid valve, the fuel return passage opens into the upper space at a position above the opening of the high-pressure fuel passage, and the gas accumulating in the constant-pressure chamber is discharged from the upper space toward the fuel tank via the fuel return passage.

A fuel pump includes rotors that rotate, a pump housing that defines a rotor housing chamber that rotatably houses the rotors, and an outer circumferential side housing that includes a cylindrical portion formed in a cylindrical shape that surrounds the pump housing from an outer circumferential side and a narrowing potion having that narrows down with respect to the cylindrical portion. The fuel pump sucks fuel into the rotor housing chamber and then discharges the fuel due to the rotor rotating. A pump cover of the pump housing includes an inlet port that sucks fuel into the rotor housing chamber, and a sliding surface portion on which the rotors slide. An outer circumferential portion of the pump cover includes a joining portion joined to the narrowing portion, and a recessed portion that is recessed adjacent to the joining portion, the recessed portion allowing the outer circumferential portion to elastically deform.

A fuel pump includes rotors that rotate, a pump housing that defines a rotor housing chamber that rotatably houses the rotors, and an outer circumferential side housing that includes a cylindrical portion formed in a cylindrical shape that surrounds the pump housing from an outer circumferential side and a narrowing potion having that narrows down with respect to the cylindrical portion. The fuel pump sucks fuel into the rotor housing chamber and then discharges the fuel due to the rotor rotating. A pump cover of the pump housing includes an inlet port that sucks fuel into the rotor housing chamber, and a sliding surface portion on which the rotors slide. An outer circumferential portion of the pump cover includes a joining portion joined to the narrowing portion, and a recessed portion that is recessed adjacent to the joining portion, the recessed portion allowing the outer circumferential portion to elastically deform.