Caterpillar Inc.

Matthew Bredesen

Dana Ray Coldren

Stephen Robert Lewis

Daniel Richard Ibrahim

Glen F Forck

James J Streicher

Ralph A Smith, Iii

Michael R Huffman

The present invention relates to fuel injectors having a free floating plunger. Traditional tappet assemblies include a plunger that is mechanically coupled to the tappet, and therefore, cannot be uncoupled over a portion of its movement during an injection event. In the event of a plunger seizure in a traditional tappet assembly, the tappet spring can be prevented from expanding, which can cause major valve train and engine damage. In addition, because the plunger in traditional tappet assemblies is moved to its upward position under the action of the tappet spring, the fuel passages can depressurize if fuel cannot refill the fuel pressurization chamber as quickly as the plunger retracts, causing cavitation bubbles. Therefore, the present invention utilizes a plunger that is not mechanically coupled to the tappet and can uncouple from the tappet during the injection event to address these and other problems related to plunger wear and failure.

Free floating plunger and fuel injector using same

An engine is provided comprising an engine housing defining at housing and has a different portion associated with each engine cylinder. Each different portion of the engine auxiliary system has a first electrical actuator coupled to a first valve and a second electrical actuator coupled to a second valve which are wired in series. For example, a fuel injection system is provided with a first electrical actuator operably coupled to a fuel pressurizer and a second electrical actuator operably coupled to a direct control needle valve. The electrical actuators are wired in series on an electrical circuit. A method of controlling a portion of the engine auxiliary system is also provided which consists of actuating a first electrical actuator with a relatively low current and actuating a second electrical actuator with a relatively high current.

Auxiliary systems for an engine having two electrical actuators on a single circuit

During assembly, shipping and handling before a mechanically-actuated fuel injector is installed into an internal combustion engine, the fuel injector tappet often accidentally disconnects from the fuel injector body. This separation of the tappet from the fuel injector body is caused by a force placed upon the tappet by a biasing means, such as a spring, that pushes the tappet away from the injector body. The fuel injector of the present application solves this problem through the interaction of a retention clip, a retention opening in the fuel injector body, and a retention slot in the fuel injector tappet. The retention clip has a body and a protrusion. The retention clip body is contained within the fuel injector body, and the protrusion extends through the retention opening and into the retention slot. After it is assembled, the fuel injector of the present application remains connected during shipping and handling and permits easy installation into an internal combustion engine.

Fuel injector tappet retention mechanism

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Chicago, IL, United States of America

Matthew Bredesen