Cummins Engine Company, Inc.

Steven D Edwards

George L Muntean

Daniel K Hickey

Jeffrey L Campbell

Dan K Hickey

Dan K Vetters

Chandresh R Shah

Ray J Amlung

Dave A Olson

David L Eastman

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 clamping load distributor and top stop disposed and connecting between a fuel injector body and a clamping device. The clamping load distributor functions as an intermediary to transmit the static clamping load from the clamping device to the fuel injector body. The clamping load distributor includes a cylindrically shaped main body having a bore extending therethrough that is disposed adjacent a coupling return spring. A cap is connected to the cylindrically shaped main body and functions as a top stop for limiting the outward axial movement of a mechanical linkage. The restriction on axial movement creates a small gap between the moving mechanical parts to allow a coating of lubrication to be obtained. The main body having a pair of clamp receiving portions formed therein for receiving a clamping load. An annular ring is formed on the bottom side of clamping load distributor radially inward from the clamp receiving portions for contacting the upper deck of the fuel injector body. The geometric relationship of the clamping load distributor functions to transfer the static clamping load radially inward towards the fuel injector units center of mass. The transferring of the clamping load radially inward results in a significant decrease in the occurrence of timing plunger seizure within the fuel injector unit.

Clamping load distributor and top stop for a fuel injector

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Columbus, IN, United States of America

Steven D Edwards