Fuel injection quantity adjustment apparatus for fuel injection pump

Claim 1

A fuel injection quantity adjustment apparatus for a fuel injection pump in an internal combustion engine, comprising: (a) a fuel injection plunger reciprocating axially within a fuel injection working space or chamber so as to force out fuel from within said working chamber to one of a plurality of fuel injectors, said plunger having a fuel injection cut-off port communicating between said working space and a reservoir chamber at a lower pressure than a predetermined pressure in the space so that fuel injection does not occur when said working space and said reservoir chamber communicate; (b) a cut-off valve slidably engaging said plunger for blocking said cut-off port to prevent communication between said working chamber and reservoir chamber and thereby allow fuel injection, said cutoff-valve being substantially stationary with respect to the axial reciprocation of said plunger and having a magnetized portion; (c) electromagnetic means for selectively producing magnetic fields of selectable polarity aligned along the axis of said plunger to displace said cut-off valve with respect to said plunger wherein said electromagnetic means comprises a pair of solenoids coaxial with, axially opposing, and radially separated from said cut-off valve, said solenoids being aligned end-to-end and wound so as to produce coaxial magnetic fields of opposite polarity; (d) an electromagnetic sensor for detecting the position of said cut-off valve and outputting a signal indicative thereof; and (e) a controller responsive to said sensor signal and to engine operating conditions for calculating a desired position of said cut-off valve in accordance with a desired fuel injection quantity, said controller comparing said sensor signal to said desired position and energizing said electromagnetic means to displace said cut-off valve toward the desired position as indicated by the difference between the desired position and the actual valve position indicated by said sensor signal.

Claim 6

The apparatus claimed in claim in 1 or 3, further including a pair of non-magnetic members, each displaced axially from one extreme of travel of said cut-off valve.

Claim 21

A method of adjusting a fuel quantity injected from a fuel injection pump in an internal combustion engine, the pump including a plunger which reciprocates axially to distribute pressurized fuel to respective injectors for engine cylinders and a cut-off valve including a permanent magnet and slidably fitted over the plunger, the plunger being provided with a fuel passageway and a cut-off port therein, the port preventing fuel injection when uncovered and capable of being covered and uncovered by the cut-off valve, a pair of solenoids disposed coaxially with and around the cut-off valve and aligned axially with each other, the method comprising the steps of: (a) energizing the pair of solenoids such that the adjacent ends of the solenoids have the same polarity; and (b) energizing one of the pair of solenoids when the other of the pair of solenoids fails with such a polarity so that the cut-off valve moves in the direction of uncovering the port in the plunger to prevent fuel injection via the plunger.

Claim 22

A method of adjusting a fuel quantity injected from a fuel injection pump in an internal combustion engine, the pump including a plunger which reciprocates axially to distribute pressurized fuel to respective injectors for engine cylinders and a cut-off valve including a permanent magnet and slidably fitted over the plunger, the plunger being provided with a fuel passageway and a cut-off port therein, the port preventing fuel injection when uncovered and capable of being covered and uncovered by the cut-off valve, a pair of solenoids disposed coaxially with and around the cut-off valve and aligned axially with each other, the method comprising the steps of: (a) energizing the pair of solenoids such that the adjacent ends of the solenoids have the same polarity; and (b) energizing one of the pair of solenoids when the other of the pair of solenoids fails with such a polarity so that the cut-off valve moves in the direction of uncovering the port in the plunger to prevent fuel injection via the plunger.