Cummins Engine Company, Inc.

David L Clark

Dennis O Taylor

Ray C Hatton

Randal L Bergstedt

Danny R Baker

William A Rankin

Eric A Pyers

Dmitri V Baraban

Kenneth S Houston

A diagnostic system for an engine is provided for which a plurality of annunciators are energized according to particular fault code sequences. A self-diagnosis mode is controlled by use of the vehicle throttle. The self-diagnosis mode can be initiated by a predetermined number of cycles of the vehicle throttle, in which a cycle corresponds to depressing and releasing the throttle beyond upper and lower limits. In one aspect of the invention, a timer is used to determine whether the predetermined number of throttle cycles occurs within a fixed time limit. If not, then the self-diagnosis mode is not activated. Once the self-diagnosis mode is activated, subsequent cycles of the vehicle throttle will increment the annunciators among the sequential fault codes.

System and method for controlling diagnostic annunciators

A dual throttle system for an internal combustion engine includes first foot pedal throttle and a second hand controller throttle. The system includes a throttle position signal generator that produces a throttle position signal at an input to an electronic engine control module (ECM). The engine control module uses the throttle position signal input to determine an engine speed and issues appropriate commands to a fuel system controller. The throttle position generator includes a first potentiometer having its wiper mechanically connected to the first throttle and its output electrically connected to the throttle position signal input of the ECM. The first potentiometer is connected in series between a voltage source in the ECM and the wiper of a second variable resistance component driven by the second throttle. The output of the second component is connected to ground to complete the series circuit. The voltage seen at the throttle signal input of the ECM is a function of the combined series resistances of the potentiometer and the second variable resistance component based upon the positions of the respective throttles.

Dual throttle control to a single throttle input

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Columbus, IN, United States of America

David L Clark