Cummins Engine Company, Inc.

Cummins Inc.

Martin W Long

David M Rix

Donald J Benson

George L Muntean

Edward Benjamin Manring

Paul D Free

Raul Krivoy

Thomas R Lee

Charles B Fry

Douglas E Dawes

Deepak Patel

Michael W Lucas

A fuel injector includes an injection control valve having a stator core that is electrically isolated from surrounding parts such as a stator housing. The stator core includes a first annulated wall having an inner surface, a second annulated wall having an outer surface, a radially extending wall connecting the first and second annulated wall, and a radially extending slot extending through the first annulated wall, the radially extending wall, and the second annulated wall. The stator core may include a limited number of contact points with the stator housing. Alternatively or additionally, an electrically insulating material may be placed between the stator core and the stator housing.

Fuel injector including an injection control valve having an improved stator core

A method of microdeburring a selected portion of bore in a workpiece with a jet of abrasive gas is provided that is particularly applicable to the removal of microburrs at the interface between the timing and metering spill ports in a fuel injector metering barrel and the plunger bore. In the method, the nozzle that emits the abrasive gas is first inserted in and aligned with the bore so that the jet is focused on the microburrs at the interface. The nozzle is then actuated for a time period long enough for the jet to remove the microburrs from the bore, but insufficient for the jet to cause unwanted radiusing of the bore at the interface that could degrade the timing characteristics of the fuel injector. The method also includes the step of interposing a shield within the metering barrel to mask off the finished surface of the barrel from unwanted abrasion. The use of a gaseous, as opposed to a liquid carrier, in combination with the precise alignment of the jet and use of an abrasion shield in the workpiece, results in a precise elimination of unwanted microburrs that is unaccompanied by unwanted widening or radiusing of the ports at their interface with the plunger bore.

Method of microdeburring a bore

In accordance with a preferred embodiment of the invention, a solenoid operated unit fuel injector, for internal combustion engines of the type which are capable of having distinct timing, metering and injection periods, and in which the same supply line serves for the delivery of fuel to both a timing chamber and a metering chamber, is improved by providing a drilling in the injector barrel which leads directly from the timing fluid flow portion of the fuel supply circuit to an injector fuel drain path, and mounting a C-shaped spring valve on the injector body for controlling dumping of fuel through the drilling at a location above that of the timing and metering spill ports.

Solenoid operated unit fuel injector with supply line backflow pressure

A mechanically pressurized electronic fuel injector is for use in internal combustion engines and is actuated by the engine valve train. The fuel injector has an injection stroke for discharging fuel into the engine and a metering stroke for receiving a predetermined volume of fuel in the injector. During the injection stroke, a coupling member contacts a timing plunger and transmits a compressive force from the engine valve train. The coupling member and the timing plunger are not mechanically connected together and are capable of independent relative movement. During the metering stroke of the injector, the timing plunger is returned to its pre-injection position under the pressure generated by the fuel entering the timing and metering plunger chambers.

Fuel injection for an internal combustion engine

A mechanically pressurized electronic fuel injector for use in internal combustion engines is actuated by the engine valve train during the injection stroke. A control solenoid is mounted to the injector and has its axis inclined with respect to the axis of the injector. A control valve passage has its axis generally coaxial with the central axis of the control solenoid. Machining of the control valve passage is accomplished through the receiving boss for the control solenoid. High pressure sealing plugs, previously required to seal orifices in the exterior surface of the injector body which were needed to provide access to drill or machine the control valve passage, are completely eliminated. The drilling and machining of the control valve passage is accomplished without drilling through the exterior surface of the injector body.

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Columbus, IN, United States of America

Martin W Long