Improved electrically operated trigger valve for fuel injection pump

Abstract

Abstract An electrically operated trigger valve for a fuel injection pump comprises a valve member (2) secured to an armature (3) to form an armature and valve member assembly. The valve member (2) is slidably mounted in a bore (4) and controls communication between the fuel inlet (5) and a fuel outlet (6). In use, the valve is maintained in its closed position by energising a stator coil (8) to attract the armature (3). When the stator is de-energised the armature and valve member assemblies moved in the valve opening direction by a valve opening spring (10). The length of the valve opening spring (10) is such that when the valve (2) is in the fully open position a gap (Y) exists between one end of the opening spring (10) and its adjacent seat (11). Accordingly, initial movement of the armature and valve member assembly in the closing position, upon subsequent energisation of the stator coil (8), is not opposed by the spring (10) until the gap (Y) has been eliminated by initial movement of the armature (3). This arrangement reduces the initial stator current necessary to produce movement of the armature and valve member assembly. It also permits a relatively stiff opening spring (10) to be used, thereby reducing the impact with which the valve member (2) engages the seat (7) upon closing, and producing a rapid initial movement in the opening direction after de-energisation of the stator coil (8).

Inventors

• 👤 Daniel Jeremy Hopley

Bibliographic Details