Cummins Engine Company, Inc.

Eric Day

Salim A Jaliwala

Allen F VanDerStuyf

The disclosure illustrates an electronically controlled fuel pump in which the microprocessor is cooled by the fuel extending to the inlet of a positive displacement pump. The cooling passage has a labyrinth flow path and the heat sinks of the microprocessor transfer heat to the passage through conduction. An auxiliary pump causes fuel to flow through the heat exchange passage during certain conditions, such as shutdown, to maintain the temperature of the microprocessor below a predetermined maximum. Transducers and other control elements associated with the microprocessor are maintained in a cavity in the fuel pump to protect them from the environment and a pivotal connection with appropriate placement of the leads is provided in the housing for ready access to these transducers and control elements.

Electronically controlled fuel pump

An add-on feedback control unit is connected to an existing mechanical governor for a turbocharged engine to control fuel flow to the engine in response to engine load and thereby maintain an adjustable low speed droop for the engine. The preload on the governor control spring is determined by a movable stop, the position of which is controlled by a pivotally mounted reset lever. A control arm is connected to the reset lever at a selected position relative to the pivotal axis of the latter. The control unit includes a housing having an interior chamber separated into first and second subchambers by a diaphragm disposed therein. One side of the diaphragm is subjected to the turbocharger boost air pressure of the engine. The control arm includes a shaft connected to the opposite side of the diaphragm and having an outwardly projecting end portion connected to the reset lever at the selected position to provide feedback in response to engine load. The engine speed is trimmed by adjusting the length of the control arm shaft, and engine speed droop is adjusted by varying the distance between the selected position and the pivotal axis of the reset lever.

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Columbus, IN, United States of America

Eric Day