Abstract: A flexible fuel compensation system for an internal combustion engine. The flex-fuel system includes a method of run fuel pulsewidth calculation which controls the amount of fuel being sent to the fuel injectors. The method calculates multipliers to be used in calculating a first and second pulsewidth multiplier and fuel injector pulsewidths.

Abstract: A method is provided for checking the function of a fuel composition sensor and for learning the percent alcohol content of a fuel used in a motor vehicle capable of operating on more than one type of fuel, as an alternative to a fuel composition sensor. The present invention improves the reliability of a motor vehicle utilizing a fuel composition sensor by allowing vehicle operation to continue uninterrupted, such as when a short or open condition exists within the sensor. The method first determines whether conditions are such that the percent alcohol content of a fuel should be "learned". If conditions are appropriated, then necessary engine operating conditions are first initialized. The oxygen sensor output signal is checked to determine whether the engine is operating too rich or lean. The value of percent alcohol content stored in the engine control unit's memory is modified in the direction of stoichiometric engine operation.

Abstract: A method is provided for controlling engine torque from a vehicle engine to an electronically controlled transmission in response to predetermined conditions existing in the transmission. The method includes the steps of saving in memory data corresponding to a spark advance and fuel flow setting, detecting whether an upshift or downshift is in process, determining if the upshift or downshift has just started if an upshift or downshift is detected, variably adjusting the spark advance setting of the engine in accordance with a detected upshift or downshift if the upshift or downshift has just started, decrementing the amount of fuel flow to the engine during adjustment of the spark advance, and returning both the fuel flow and spark advance to its original setting.

Abstract: A method of controlling the target idle speed of an internal combustion engine having sensors for monitoring engine coolant temperature, engine speed, and battery voltage.

Abstract: A method is provided for controlling knock on an internal combustion engine. The method includes the steps of determining a maximum value of knock and determining whether conditions are right for updating the maximum value of knock. The method also includes using an unmodified spark advance if conditions are not right for updating the maximum value of knock and modifying the spark advance if conditions are right for updating the maximum value of knock.

Abstract: The present invention provides a method for controlling the partial frictional engagement between the torque converter and the vehicle engine called "partial lock-up" mode of operation to reduce the rotational speed difference between torque converter and the engine. The present invention eliminates surges that occur for partial lock-up which may result in a harsh shift.

Abstract: A method of determining and controlling a lock-up of a torque converter in a four-speed automatic transmission for full or partial frictional coupling between the torque converter and the vehicle engine. The method includes the steps of checking conditions that preclude partial lock-up operation and unlocking the torque converter if partial frictional coupling is precluded. The method also includes setting initial conditions for going from unlock to partial frictional coupling and checking for conditions that allow full frictional coupling operation. The method further includes fully frictional coupling the torque converter if conditions allow full frictional coupling operation, otherwise, partially frictionally coupling the torque converter.

Abstract: A method of reducing stall torque from the engine to the transmission based on a desired engine speed to minimize the potential interference and possible damage to any of the electronically controlled transmission components for an automatic transmission.

Abstract: A method of reducing the shift torque from the engine to the automatic transmission system in response to predetermined conditions existing in the transmission so as to minimize the potential interference and possible damage to any of the electronically controlled transmission components.