Importance

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Abstract

A method for implementing an intelligent cruise control using standard engine control modes includes determining the distance and closing rate relative to a forward object or vehicle and using this information to implement a distance control mode and a speed control mode. The distance control mode maintains a selectable headway range relative to a forward object or vehicle and may include accelerating the vehicle or decelerating the vehicle by defueling, engaging an engine brake, or downshifting the transmission when engine speed permits. The speed control mode maintains a selectable cruising speed if no target vehicle is detected. This cruising speed set point also functions as an upper limit while in the distance control mode. The system and method effect the intelligent cruise control functions utilizing control logic external to the electronic engine control module utilizing the engine speed control mode or engine speed and torque limiting control mode of SAE J1922 or SAE J1939 standards. Alternatively, a cruise control limit speed may be broadcast via SAE J1587 to reduce the vehicle speed upon approaching a forward vehicle so as to reduce the need for driver intervention. The invention may periodically switch between engine control modes to avoid any control mode timeout imposed by some engine manufacturers.

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First Claim