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A fuel injector (10) is provided for each cylinder of an internal combustion engine, the injector including an electronically operated control valve (146) disposed between supply passage (42) and a timing chamber (98) to control the admission of fuel into and out of the timing chamber. A primary pum

A fuel injector (10) is provided for each cylinder of an internal combustion engine, the injector including an electronically operated control valve (146) disposed between supply passage (42) and a timing chamber (98) to control the admission of fuel into and out of the timing chamber. A primary pumping plunger (62) and a secondary plunger (90) are axially spaced within the central bore of the injection body, and a normally closed injection nozzle (14) is situated at one end of the injector body. A mechanical linkage (27, 28, 30) associated with the camshaft of the engine drives the primary pumping plunger (62) against the bias of a main spring (18). The timing chamber (98) is defined between the plungers (62, 90) and a metering chamber (128) is defined between the secondary plunger (90) and the nozzle (14). An electronic control unit (52) responds to engine operating conditions, and delivers a timing and metering signal to the control valve (146) to close the valve and seal the timing chamber for a controlled period of time. The sealed timing chamber forms a hydraulic link, so that the plungers (62, 90) move in concert during the injection and metering phases of the cycle of operation. When the signal from the ECU is terminated, the control valve opens, and breaks the link so that the primary plunger (62) moves independently of the secondary plunger (90) which is biased in a set position by a spring (96) after termination of the control signal. The timing function can be adjusted by the ECU relative to any preselected position of the crankshaft to optimize engine performance, while the metering function is achieved in a proportionate manner relative to the degree of camshaft rotation. A cam (22), having a linear portion, controls the mechanical linkage, and thus the primary pumping plunger (62), to produce the proportional metering function.

대표청구항 ▼

A fuel injector adapted to be disposed in timed operative relationship to the combustion chamber of an internal combustion engine in response to an electronic control unit, said injector comprising: (a) a body having a bore; (b) a primary pumping plunger and a secondary plunger spaced therefrom, sai

A fuel injector adapted to be disposed in timed operative relationship to the combustion chamber of an internal combustion engine in response to an electronic control unit, said injector comprising: (a) a body having a bore; (b) a primary pumping plunger and a secondary plunger spaced therefrom, said primary and secondary plungers being positioned within said bore for axial movement; (c) a nozzle situated at the end of the said bore remote from said primary pumping plunger for releasing fuel into the combustion chamber; (d) a timing chamber defined in said bore between said primary pumping plunger and said secondary plunger adapted to create a coupling between said plungers; (e) a metering chamber defined in said bore between said secondary plunger and said nozzle; (f) passages in said body adapted to introduce fuel under pressure into said timing chamber and said metering chamber; (g) electronically operated control valve means situated intermediate said passages and said timing chamber to seal said timing chamber and control the coupling of said primary to said secondary plungers; (h) said control valve means adapted to be selectively energized by the electronic control unit to regulate (1) the timing of the discharge of fuel from the metering chamber through the nozzle, and (2) the quantity of fuel discharged through the nozzle; and (i) passage means and check valve means supported by said secondary plunger for controlling the flow of fuel between said body passages and said timing and metering chambers.