Stratfield-charge engine and fuel ignition-injection plug therefor

Claim 1

A fuel injection-ignition plug for a stratified-charge engine comprising: a tubular body having inner and outer ends; a pair of spaced electrodes at the inner end of said body defining an intervening spark gap; a high tension conductor accessible at the outer end of said body and connected to one electrode for conducting high tension ignition voltage to the latter electrode; fuel injection means within said plug having a fuel inlet at the outer end of said body and a fuel injection port at the inner end of said body for injecting fuel into the immediate vicinity of said spark gap; said fuel injection means comprises a fuel injection pump within said body; said plug is adapted to be installed in said engine in a manner such that said electrodes are positioned within an engine cylinder and said fuel injection port is exposed to the pressure within said cylinder; said pump is a positive displacement pump including an expansible pumping chamber communicating with said fuel inlet and fuel injection port and bounded in part by a movable pressure wall which is urged in one direction by fuel pressure within said chamber to enlarge said chamber and in the opposite direction by compression pressure within said cylinder to expel fuel from said chamber into said cylinder, a spring for urging said pressure wall in said latter direction, a check valve between said chamber and fuel inlet which opens to admit fuel from said inlet to said chamber and to block reverse fuel flow, and a normally closed spring loaded fuel injector valve for blocking fuel flow through said injection port into said cylinder until the fuel pressure within said pumping chamber attains a preset pressure level; said movable pressure wall comprises a plunger movable longitudinally within said plug body; said plunger is hollow and contains said pumping chamber and the inner end of said plunger is exposed at the inner end of said body, whereby cylinder pressure at the inner end of said body urges said plunger outwardly Relative to said body; said electrodes comprise annular electrodes mounted on the inner end of said body and the inner end of said plunger, respectively; said check valve comprises a valve sleeve parallel to the longitudinal axis of said plunger and slidably engaging said plunger, whereby said valve sleeve tends to move longitudinally with said plunger by virtue of the frictional drive between said plunger and valve sleeve, and said valve sleeve being movable outwardly with said plunger relative to said body to the closed position and inwardly with said plunger relative to said body to the opened position; and said fuel injection port and injector valve are carried by the inner end of said plunger.