Abstract: An electronic control system for a multiple ratio automotive transmission having pressure operated clutch and brake servos for controlling ratio changes, solenoid operated valves for triggering operation of shift valves in a valve circuit that communicates with the servos, a microprocessor for developing control signals in response to input variables that measure engine torque, engine speed, vehicle speed and a driver-actuated range selector, the shift valves responding to the control signals in accordance with a control strategy that effects controlled response of the shift valves to meet varying road speed, engine torque and road conditions with high quality shift performance.

Abstract: An electronic control system for scheduling gearshifts in a four speed automatic transmission includes storing in electronic memory accessible to a microprocessor, six functions relating vehicle speed to throttle position, one function being related to each upshift and downshift. Gearshifts are made by probing computer memory with current values for throttle position and vehicle speed, and determining on the basis of the stored shift schedule whether an upshift of downshift is required. Upshift points are determined also on the basis of the maximum engine speed when a wide open throttle condition is detected. Electronic memory continually accessible to the microprocessor is updated with new calculated values of the ratio NOV divided by base NOV. Vehicle speed from a stored schedule of gearshift values is corrected with the calculated ratio to account for changes in the driveline components from their condition when originally installed and differences from a calculated base NOV value.

Abstract: An electronic control system for operating a torque converter clutch during a transmission gearshift includes a vehicle speed sensor and engine speed sensor, a hydrodynamic torque converter located between the engine and the transmission, a solenoid-operated hydraulic valve, which engages and disengages the torque converter clutch in accordance with the energized and deenergized state of the solenoid in accordance with the logic of the control system. The converter clutch is locked while operating in the original gear ratio, then unlocks during the gearshift, and relocks after the upshift is completed. The speed ratio of the torque converter is rapidly determined in terms of the number of clock ticks occurring between pulses whose frequency is proportional to engine speed. The current speed ratio is determined during interrupts occurring at short intervals during a background pass.

Abstract: An electronic control system for scheduling gearshifts in a four speed automatic transmission includes storing in electronic memory accessible to a microprocessor, six functions relating vehicle speed to throttle position, one function being related to each upshift and downshift. Gearshifts are made by probing computer memory with current values for throttle position and vehicle speed, and determining on the basis of the stored shift schedule whether an upshift or downshift is required. Upshift points are determined also on the basis of the maximum engine speed when a wide open throttle condition is detected. Ambient barometric pressure alters the vehicle speed and engine speed attained at high altitude in comparison to those speeds that result for the same throttle position at sea level.

Abstract: Controlling the speed of an engine used with an automatic transmission to reduce tip in jerk includes determining any difference between transmission gearset speed and engine speed. Engine speed is increased if it is below transmission gearset speed so as to reduce any speed differential between the engine and transmission gearset.

Abstract: An electronic control valve system for an automatic, multiple-speed motor vehicle transmission having a torque converter with a lockup clutch and change-speed gearing adapted for four forward ratios and one reverse ratio, a converter lockup clutch control valve in conjunction with a lockup clutch shift valve adapted to control the lockup clutch, and electronic microprocessor control means for establishing ratio changes between the fourth ratio and the third ratio in accordance with separate upshift schedules and separate downshift schedules stored in the memory registers of the microprocessor, the separate registers being addressed in accordance with whether the lockup clutch is applied or released.