Abstract: An electronic engine control controls the selection and confirmation of automatically selectable gears in a manual/automatic transmission. Failure to disengage the engine from the transmission within a predetermined time period, failure to reach a predetermined synchronous engine RPM window within another predetermined time period and failure to confirm gear engagement within yet another predetermined time period are three automatic shift failure modes which may cause an automatic shift attempt to fail or be aborted. A fourth automatic shift failure may occur if the clutch pedal is depressed during an automatic shift attempt. If any of the foregoing automatic shift failure mechanisms is detected, an error recovery algorithm which forms a part of the present invention determines the easiest/safest transmission gear to command to prevent the driver from having to manually attempt to engage the transmission after a failed automatic shift attempt.

Abstract: An apparatus and method of electronically controlling a manual/automatic transmission after a power reset is provided. Within a predetermined time period after a power reset, the current commanded transmission gear is held, or alternatively the highest of the electronically selectable gears is commanded, until an accurate determination of the vehicle speed can be made. If the vehicle speed is thereafter determined to be below a minimum vehicle speed value, the transmission is commanded to the neutral position, or alternatively, the lowest of the electronically selectable gears is commanded. If the vehicle speed is above the minimum vehicle speed value, or alternatively, above a maximum vehicle speed value, then the transmission is commanded to the highest of the electronically selectable gears. In either case, further electronic shifts are inhibited for a predetermined time period after recovery from the power reset is accomplished.

Abstract: A control system for controlling automatic shifting of a manual/automatic transmission is disclosed including a cruise control system and an auto-shift mode for controlling automatic upshift and downshift operations between the top two gears of a heavy duty truck transmission. Certain failures of equipment or incorrect driving habits of operators are corrected for with algorithms which prevent undesirable operating conditions which compromise the acceptability of an electronically controlled heavy duty truck transmission equipped vehicle. The mechanism by which auto-shift operation of the transmission is requested is also compared with parameters such as vehicle speed and engine speed in order to determine whether gears should be engaged or disengaged, the gears being those subject to auto-shift control of the system controller.

Abstract: A control system for controlling automatic shifting of a manual/automatic transmission is disclosed including a cruise control system and an auto-shift mode for controlling automatic upshift and downshift operations between the top two gears of a heavy duty truck transmission. Certain failures of equipment or incorrect driving habits of operators are corrected for with algorithms which prevent undesirable operating conditions which compromise the acceptability of an electronically controlled heavy duty truck transmission equipped vehicle. The mechanism by which auto-shift operation of the transmission is requested is also compared with parameters such as vehicle speed and engine speed in order to determine whether gears should be engaged or disengaged, the gears being those subject to auto-shift control of the system controller.