Abstract: A transmission control system for a vehicle includes a driver input device that generates a driver input signal and a control module that receives the driver input signal. The control module determines an operating mode of a transmission based on the driver input signal and selects a gear ratio of the transmission based on the operating mode. The operating mode includes one of a maximum performance mode, a power mode and a fuel economy mode.

Abstract: An improved adaptive pressure control which accounts for nonlinearity in the relationship between fluid pressure and shift time. To account for nonlinearity in the relationship between cumulative shift time error and corrective pressure, the control utilizes an empirically derived table of shift time vs. controlled pressure to develop a raw pressure error in lieu of a shift time error. The adaptive pressure correction, in turn, is developed in relation to the cumulative pressure error. This removes the effect of system nonlinearity from the adaptive control, allowing more accurate adaptive convergence than was heretofore achieved.

Abstract: An improved adaptive line pressure control which detects the occurrence of run-through and overrides the normal adaptive pressure control in response to a detected run-through condition so that the line pressure during subsequent shifting is increased instead of decreased. A run-through condition is detected by measuring and comparing first and second time indications corresponding, respectively, to the interval of ratio change during the shift (shift time), and the interval between the generation of a shift command and the actual initiation of ratio change (delay time).

Abstract: A driver circuit for the solenoid actuator coils of a direct pressure electronic transmission control. The circuit is remotely configurable for satisfying the requirements of both shifting and nonshifting modes of operation. In shifting modes of operation, a common snubber element is activated to permit fast commutation of the coil current while protecting the switching devices. In nonshifting modes of operation, dedicated free-wheeling diodes are activated to circulate the coil energy at turn-off of the switching devices to facilitate reduction energy consumption and heating.

Abstract: A clutch-to-clutch power-on downshift in a motor vehicle automatic transmission is initiated by reducing the torque capacity of the off-going clutch, permitting the transmission input speed to increase toward its post shift value. When the slippage across the off-going clutch exceeds a reference, the reduction of its torque capacity is suspended, permitting continued increase of the transmission input speed. When the slippage across the on-coming clutch falls below a reference value, the on-coming and off-going clutches are concurrently applied and released to complete the shift. The transmission input speed substantially achieves its post shift value at the time of such apply and release, resulting in reduced shift-related output torque disturbance.

Abstract: An adaptive shift control system for regulating the operation of a fluid operated torque establishing device associated with a specified speed ratio in a motor vehicle automatic transmission. Shifting from a currently engaged speed ratio to the specified speed ratio includes a preparation phase during which fluid is supplied to the torque establishing device for a predetermined time to fill the same in preparation for torque transmission, and a completion phase during which further fluid is supplied to the device to initiate and progressively increase the transmission of torque therethrough. The change in transmission input speed due to the initiation of torque transmission through the torque establishing device is identified and used to detect the occurrence of overfill or underfill conditions. The predetermined time is adjusted based on such detection so as to adaptively compensate for sources of error which degrade the shift quality by causing overfill or underfill conditions.

Abstract: Clutch-to-clutch downshifts in the course of a coast mode of operation are effected by releasing the off-going clutching device at a time determined in relation to the vehicle speed and deceleration rate, and applying the on-coming clutching device a predetermined time thereafter such that the apply occurs when the engine speed is substantially equal to the transmission input speed in the downshifted speed ratio. The predetermined time defines an neutral interval during which the on-coming clutching device is filled with hydraulic fluid in preparation for engagement, and the engine speed assumes its neutral idle value. At the end of the predetermined time, the engine speed and the transmission input speed in the downshifted speed ratio are at the neutral idle value, and the on-coming clutching device is applied to complete the shift.

Abstract: An adaptive shift control system for regulating the operation of a fluid operated torque establishing device associated with a specified speed ratio in a motor vehicle automatic transmission. Shifting from a currently engaged speed ratio to the specified speed ratio includes a completion phase during which fluid is supplied to the torque establishing device in accordance with a predetermined pressure schedule to initiate and progressively increase the transmission of torque therethrough. The time required to complete a specified portion of the speed ratio progression is identified and compared to a reference time representative of the time required to complete the progression when the shift quality is not degraded. The predetermined pressure schedule is adjusted based on such comparison so as to adaptively compensate for sources of error which affect the increase of torque transmission through the torque establishing device during the completion phase and cause the shift quality to be degraded.

Abstract: A load control system for controlling the field current of an alternating current generator and the idle speed control system for the engine that drives the generator. A voltage regulator senses the output voltage of the generator and controls field current by causing a semiconductor switch connected in series with the field winding to switch on and off in accordance with the magnitude of the sensed voltage. The voltage regulator is controlled to operate in a conventional manner when engine speed is higher than engine idle speed. When engine speed is in an idle speed range the duty cycle or on time of the semiconductor is controlled such that consecutive occurring on times are gradually increased to gradually increase field current when the output voltage of the generator is below a desired regulated value.

Abstract: A processing circuit for use in an internal combustion engine closed loop air/fuel mixture controller is responsive to the output of an oxygen sensor exposed to the exhaust gas output of the internal combustion engine to provide a signal that indicates the sense of the deviation of the oxidizing/reducing conditions of the engine exhaust gases from a predetermined condition (usually stoichiometry). The processing circuit compares the output signal from the oxygen sensor with a pair of reference levels to provide the signal that indicates the sense of the deviation of the condition of the exhaust gases from the predetermined condition and which is independent of the effects of the absolute levels of the oxygen sensor and independent of the variance between the sensor response to changing air/fuel ratios in one direction and to sensor response to changing air/fuel ratios in the opposite direction.