Cummins Engine Company, Inc.

Dan K Vetters

George L Muntean

Edward D Smith

Norman C Blizard

Jeffrey L Campbell

Dan K Hickey

Raymond J Amlung

Steven D Edwards

Mark Pounder

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 leak prevention device including an expandable chamber and control valve for preventing fuel leakage into the combustion chambers of a internal combustion engine equipped with a common rail fule injection system including open nozzle injectors and a shut off valve mounted in the common rail upstream of the fuel injectors to isolate, when closed, the fuel injectors from the source of fuel under pressure. The expandable chamber contains a variable volume held in its collapsed condition during engine operation and expanded upon engine shutdown sufficiently to prevent the flow of fuel from any injector into the corresponding combustion chamber. The control valve may be a three way valve for controlling the expansion of the variable volume of the expandable chamber The leak prevention device includes a housing assembly connected with a fuel drain and contains an outlet passage fluidically connected at one end with the variable volume and at the other end with the fuel drain and an outlet check valve for allowing fuel to flow in only one direction from the variable volume into the fuel drain. A control circuit is provided to energize solenoids for operating the shut off valve and control valve.

Variable volume chamber device for preventing leakage in an open nozzle

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Columbus, IN, United States of America

Dan K Vetters