Fuel injection device for internal combustion engines

An automatic valve-type fuel injector comprising:

• an elongated body having a longitudinally extending bore formed therein and a fuel inlet port communicating with the bore;
• a valve element having a hemispherically-shaped head portion and a stem portion to the leading end of which the head portion is joined;
• a valve seat fixed to the leading end of the bore and having a central aperture through which the stem portion of the valve element extends with an ample clearance therebetween for the passage of fuel and which is provided with an annular edge for the fuel-tight contact during non-injection period with the cooperating hemispherical surface of the head portion of the valve element;
• an adjusting rod extending through the bore to project beyond the rear thereof;
• a tension spring provided at its opposite ends with hooks which engage with the rearward end of the stem portion of the valve element and leading end of the adjusting rod, respectively;
• a seal member housed in a rearward end of the bore and receiving the adjusting rod in a fuel-tight fashion;
• a locking member disposed outside the body for locking the adjusting rod at its desired longitudinal position so as to set the force of the tension spring that determines the valve opening pressure;
• and
• a filter element housed within the bore between the fuel inlet port and the valve seat, said filter element having a central aperture formed therein for guiding radially the adjusting rod.

An automatic valve-type fuel injector comprising:

• an elongated body having a longitudinally extending bore formed therein and a fuel inlet port communicating with the bore;
• a valve element having a hemispherically-shaped head portion and a stem portion to the leading end of which the head portion is joined;
• a valve seat fixed to the leading end of the bore and having a central aperture through which the stem portion of the valve element extends with an ample clearance therebetween for the passage of fuel and which is provided with an annular edge for the fuel-tight contact during non-injection period with the cooperating hemispherical surface of the head portion of the valve element;
• an adjusting rod extending through the bore to project beyond the rear thereof;
• a tension spring provided at its opposite ends with hooks which engage with the rearward end of the stem portion of the valve element and leading end of the adjusting rod, respectively;
• a seal member housed in a rearward end of the bore and receiving the adjusting rod in a fuel-tight fashion;
• a locking member disposed outside the body for locking the adjusting rod at its desired longitudinal position so as to set the force of the tension spring that determines the valve opening pressure;
• and
• a guiding member housed within the bore between the fuel inlet port and the valve seat such that the fuel may pass therethrough, said guiding member having a central aperture formed therein for guiding radially the adjusting rod.