Vehicle engine control by determining torque-converter speed ratio

摘要

A vehicle-control method for a vehicle having an internal-combustion engine coupled to a torque converter which is coupled to a transmission. A speed ratio for the torque convener is determined, i.e. the ratio of torque-converter-output speed to torque-convener-output speed. If it is determined that the speed ratio is within a predetermined range, then an operating parameter of the engine (e.g. throttle position, fuel-injection amount) is adjusted to control a change in an engine output (e.g. engine output or engine torque) to be less than a preselected value. Alternatively, an engine-operating parameter may be controlled at a preselected rate. By controlling an operating parameter of the engine in these ways it is possible to pass gently through the transmission lash zone, thereby improving driver comfort.