Caterpillar Inc.

Errol W Davis

Daniel Reese Puckett

Brian G McGee

John Parker Timmons

Larry E Schmidt

James A Antone

Paul M Young

Ronald J Penick

Gary L Cowden

John J Wunning

Matthew E Schulman

Mohamad Z Deiri

Kenneth D Gihring

An apparatus and method for varying the current levels of a fuel injection signal used in connection with an electronically controlled hydraulic actuator unit injector fuel system is disclosed. The apparatus and method varies the current level of the fuel injection signal delivered to the unit injector based on sensed engine parameters, which preferably include a sensed pressure of hydraulic actuating fluid and a sensed temperature of the engine.

Electronic control for a hydraulically activated, electronically

A solenoid driver circuit is controlled by an electronic control module ('ECM') and eliminates many components required for a high voltage power supply required by the prior art. The solenoid driver circuit includes a high voltage select switch, a select switch and a modulation switch that are controlled by the ECM. The ECM causes the switches to be opened and closed so that the back EMF created by the solenoid coil when the modulation switch is opened can be recaptured by charging a capacitor. That energy can then be used to energize the solenoid coil.

Solenoid injector driver circuit

A control system for an internal combustion engine having a plurality of cylinders and a rotatable crankshaft. Each cylinder has an electronically actuatable intake valve, exhaust valve and fuel injector. The control system includes a sensor which monitors the rotation of the crankshaft and responsively produces a crankshaft pulsetrain. A computer produces operator parameter signals. The operator parameter signals including one of a plurality of operating modes of the engine. A first microprocessor receives the crankshaft pulsetrain, responsively determines the speed of the engine and produces a signal representative of the determined engine speed. A second microprocessor receives the operator parameter signals and the engine speed signal, responsively determines valve and injection events for each cylinder to responsively achieve the one engine operating mode. The second microprocessor produces signals representative of the determined valve and injection events.

Control system for an internal combustion engine

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Chillicothe, IL, United States of America

Errol W Davis