Abstract: The net engagement pressure of a torque converter clutch is controlled in response to a commanded slip and a slip error indication, for isolating engine torque perturbations from the vehicle driveline. The transmission of an excessive level of engine speed perturbation is detected and used to develop a correction amount for the measured slip. The correction amount increases the slip error indication and causes the slip to be controlled at a higher level, thereby reducing the amount of transmitted engine torque perturbation.

Abstract: The output power of an automotive powertrain including a throttled engine and a stepped ratio transmission is maintained substantially constant during upshifting of the transmission. The powertrain output torque is actively measured during shifting, and the output power of the powertrain is controlled by modulation of the engine throttle position and spark timing, and the transmission clutch apply pressures.

Abstract: The net engagement pressure of a torque converter clutch having a negative slope capacity vs. slip characteristic is controlled to stably regulate the clutch slip, and thereby isolate engine torque perturbations from the vehicle driveline. The pressure is scheduled with a proportional term responsive to transient slip speed deviations and an integral term responsive to steady state slip speed deviations. Feed forward terms responsive to the throttle changes which force steady state slip speed deviations act to increase the speed of response of the integral term.

Abstract: Engine air flow is controlled by principal and supplementary throttles--the principal throttle being positioned by a stepper motor but also having a mechanical linkage to assure at least partial throttle opening when required, and the supplementary throttle being positioned by a mechanical linkage to permit primary control of engine output by the principal throttle while assuring that engine output is minimized when required.

Abstract: A power control system for a motor vehicle engine and fluid pressure automatic transmission wherein the engine power control setting is adjusted to bring about correspondence between the actual driveline power output and the requested power output indicated by the accelerator pedal position. A follow up control system adjusts the transmission throttle valve cable according to the accelerator pedal position except under engine operating conditions associated with reduced fuel efficiency at which time the follow up control system is interrupted and the throttle valve cable is adjusted to initiate a downshift in the transmission. The follow up control system is reestablished when the available power output in the higher gear is sufficient to satisfy the requested power output in an efficient manner.