Cummins Engine Company, Inc.

Toshiba Corporation

Jeffrey L Campbell

Lester L Peters

John T Carroll, Iii

Joseph C Bentz

Julius P Perr

Thomas M Yonushonis

George L Muntean

Katsuhiro Shinosawa

Timothy A Warlick

Dan K Hickey

Steven D Edwards

Dan K Vetters

Michael E Lucas

Kuang-Wen T Wan

Ray J Amlung

An improved cam operated, open nozzle, unit injector is disclosed including an injector body formed by a barrel, spring housing, and nozzle and containing a central bore for receiving a variable length plunger assembly mounted for reciprocal movement within the injector body wherein the variable length plunger is formed by an outer plunger and inner plunger combined with a timing plunger, mounted between the inner and outer plungers to form a collapsible timing chamber into which a variable quantity of fuel may be metered and expelled on a cycle by cycle basis to provide a variable effective length to the plunger assembly to cause controlled variation in injection timing based on variation in the timing fluid supplied to the injector and wherein the timing plunger is provided with a radial flange for engaging a stop formed in the injector barrel to hold the timing plunger in a predetermined precise location during metering of timing fluid into the collapsible timing chamber and to render the injector timing insensitive to unpredictable pressure variations. The disclosed injector may include a damping chamber for receiving the radial flange of the plunger to eliminate damaging engagement between the timing plunger and the injector barrel. Improved fuel flow passages, check valves and an improved coupling between the outer plunger and the injector's outer return spring are provided along with means for easily changing the rated injection quantity of the disclosed injector.

Unit injector with hard stop timing plunger

A low inertia, wear-resistant needle valve assembly is provided for an internal combustion engine closed nozzle unit fuel injector. The needle valve assembly includes a needle and spring retainer subassembly made from an advanced structural ceramic, such as silicon nitride. A valve seat subassembly in the injector cup is made from a combination of metal and ceramic. The assembly materials and configuration provide maximum control over the efficiency of the injection event so that the fuel injection event can be terminated quickly, thereby allowing more effective control over exhaust emissions.

Low inertia, wear-resistant valve for engine fuel injection systems

A highly wear-resistant plunger assembly for a fuel injector, particularly an open nozzle fuel injector, is provided. The wear-resistant plunger assembly of the present invention includes components formed from wear-resistant materials specifically including, but not limited to, ceramics and metals capable of withstanding the high temperatures and frictional forces produced by prolonged motoring and other potentially adverse engine operating conditions. Different portions of the plunger assembly may be formed from different kinds of wear-resistant materials.

Wear resistant fuel injector plunger assembly

A fuel injector includes an injector housing having a plunger assembly disposed within a central axial bore and including a lower plunger, an intermediate plunger, and an upper plunger. The lower plunger reciprocates within the central bore to meter a variable quantity of fuel during downward portions of the reciprocating motion. A timing spring is wound around the upper portion of the lower plunger to bias the lower plunger upwardly. A timing chamber formed between the upper and intermediate plungers receives timing fluid to create a hydraulic link between the plungers. Timing fluid exits the timing chamber through a central passage, which may have a reduced area regulating orifice, formed through the intermediate plunger, which is ordinarily closed by a valve mechanism. The valve mechanism is acted upon in part by the timing spring. To improve the pressure regulation using a higher spring load and to accommodate a larger area drainage passage, a valve spring biases closed the passage. The force provided by the valve spring is predetermined to open the valve mechanism and drain timing fluid when the timing fluid pressure exceeds the maximum pressure during injection. After injection is completed, timing fluid exits from the timing chamber either through the central passage or through a spillport which is closable by the nonbeveled lower portion of the upper plunger.

High pressure unit fuel injector with timing chamber pressure control

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Hope, IN, United States of America

Jeffrey L Campbell