Cummins Engine Company, Inc.

Daniel K Hickey

Daniel K Vetters

Bruce E Varney

George L Muntean

Chandresh R Shah

John D Crofts

Gary L Gant

Harry L Wilson

Edward Benjamin Manring

Kevin L Vogt

Jeffrey J Sullivan

Mustahsen Gull

Steven D Edwards

Hisham K Mozaffar

Tibor Kiss

Dave A Olson

David L Eastman

A unit fuel injector is provided which includes a threadless injector body attaching device for attaching an upper body section of the fuel injector to a lower body section while avoiding imparting a transverse load to the upper body section thereby minimizing bore distortion, plunger wear and the likelihood of injector failure. The threadless injector body attaching device includes a groove formed in the lower end of the upper body section and one or more apertures extending through the lower body section for positioning adjacent the groove. Also, one or more pins are provided for insertion into a respective aperture and connection to the lower body section. The groove and opposing aperture or apertures are sized to create a slip fit to avoid a contact force between the pin or pins and the upper body section. Upon assembly, the pin, aperture and groove create a relatively loose connection between the upper body section and the lower body section without transverse loads while utilizing the clamping load imparted by an injector mounting clamp to apply the necessary sealing load to the injector body to create a fluid seal between the upper and lower body sections.

Pinned injector assembly

An improved unit fuel injector is provided which effectively and precisely controls the timing of fuel injection by avoiding outside influences acting on a timing plunger. The unit fuel injector includes a timing plunger positioned between upper and lower plungers, a timing chamber positioned between the timing plunger and upper plunger and a spring chamber positioned between the timing plunger and a metering chamber for containing one or more springs for biasing the plungers. A spring chamber drain valve device is provided for directing fuel in the spring chamber to a low pressure drain while isolating the spring chamber from the low pressure drain system thereby preventing pressure variations in the drain system from entering the spring chamber and acting on the timing plunger. In addition, a scavenge circuit is provided to direct a scavenging flow of fuel and combustion gas from the injector directly to the low pressure drain without communication with the spring chamber. Consequently, pressure variations in the spring chamber are minimized thereby reducing the variations in biasing force on the timing plunger 38 to permit precise control of the timing fluid metering into the timing chamber by simply varying the timing fluid pressure.

Fuel injector with isolated spring chamber

A top stop assembly for a fuel injector is provided which includes a top stop housing having a threadless injector engaging portion positioned at one end of the housing for threadlessly engaging the outer diameter portion of an injector barrel to minimize inward bore distortion. The top stop is preferably formed integrally on the top stop housing body to create a predetermined axial length of the housing which defines a predetermined outer limit of a retraction stroke of an injector plunger assembly, i.e. a top stop position. The top stop position is set by selecting a top stop housing having a predetermined axial length corresponding to the desired top stop position thereby reducing costs and avoiding loosening problems associated with multi-part top stop assemblies.

Top stop assembly for a fuel injector

An electromagnetic fuel injection control valve positioned inside a fuel injector, i.e. a unit injector, for providing fast response and high pressure capability while minimizing the size and complexity of the injector. The control valve includes a valve housing having a supply inlet and fuel outlet, a center tube having a center passage and an annular valve seat, a control valve sleeve slidably mounted on the center tube and an actuator assembly having a coil spring, a stator and an armature. The control valve sleeve moves between an open position permitting fuel to flow between the supply inlet and the fuel outlet and a closed position which sealingly engages the annular valve seat for blocking the flow of fuel between the supply inlet and the fuel outlet. The coil spring biases the control valve sleeve in an open position and is positioned around the center tube. The stator is also axially positioned around the center tube and includes multiple poles. The armature connects to the control valve sleeve and reciprocates when solenoid is activated to allow for high pressure fuel injection into the combustion chamber of an internal combustion engine.

Electromagnetic fuel injector control valve

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

A distortion control ring disposed and connected between a fuel injector body and a clamping device. The distortion control ring is utilized as an intermediary for transmitting a static clamping load from the clamping device to the fuel injector body. The distortion control ring includes a cylindrical shaped main body having a bore extending therethrough between an upper surface and a lower surface. The upper surface of the main body being adapted for mounting a return spring thereon. The lower surface having an annular portion for contacting the fuel injector body. A radial flange is formed on the distortion control ring adjacent to the main body for contacting the clamping device and receiving the static clamping load. The clamping device engages the radial flange at a distance radially outward of where the lower surface of the main body contacts the fuel injector body. This geometric relationship between the radial flange and the lower surface of the main body transfers the static clamping load to a central portion of the fuel injector body. By transferring the static clamping load to a more central portion of the fuel injector body there is a corresponding reduction in the failure rate of fuel injector units.

Distortion control ring for a fuel injector

Growing community of inventors

Greenwood, IN, United States of America

Daniel K Hickey