Abstract: A shift control apparatus for an automatic transmission provides a normal-temperature shift pattern and a high-temperature shift pattern. The high-temperature shift pattern is selected when a temperature of hydraulic oil for the transmission satisfies a predetermined condition. Once the high-temperature shift pattern has been selected, the apparatus inhibits the switching to the high-temperature shift pattern for a predetermined duration, thereby to avoid an excessively frequent hunting between the shift patterns.

Abstract: A shift control apparatus for an automatic transmission provides a normal-temperature shift pattern and a high-temperature shift pattern. The high-temperature shift pattern is selected when a transmission fluid temperature satisfies a predetermined condition. The switching of the shift pattern is inhibited if the vehicle speed is lower than a predetermined speed, even when the temperature related to the transmission or engine has been judged to be higher than a predetermined temperature.

Abstract: An apparatus is disclosed which prevents occurrence of an engine stalling in a power train of an automotive vehicle, including an engine and a lock-up type automatic transmission. The apparatus is operative during a braking operation of the vehicle and includes an engine controller to perform an idling speed control for the engine, and a transmission controller to perform a lock-up releasing control for releasing the torque converter from the lock-up mode. When the lock-up releasing control is being performed, the engine controller continuously performs the idling speed control and thereby prevents occurrence of engine stalling.

Abstract: A predetermined control on an engine, i.e., a fuel-cut operation, is executed after an accelerator has been released under predetermined conditions when vehicle speed is higher than a fuel-cut vehicle speed value and engine speed is higher than or equal to a fuel-cut engine speed value. In an automatic transmission drivingly connected to the engine via a torque converter, a gear shift is initiated after the accelerator has been released. During a shift of the same kind, there occurs a variability in shift shock between the cases with and without the execution of the fuel-cut operation. In order to reduce this variability, the execution of the fuel-cut operation is inhibited until completion of the shift after the accelerator has been released under the predetermined conditions.

Abstract: The opening degrees of a manually operable engine throttle valve and a traction control controlled throttle valve are compared and the opening degree of the one which is closed the most is used to control the level of line pressure in an automatic transmission.

Abstract: A system and method for controlling an operation of an internal combustion engine of a vehicle having an automatic transmission in which at least one of predetermined fuel supply recovery engine revolution speed or predetermined fuel supply cut-off engine revolution speed is varied during the engine deceleration condition according to a state of operation of the automatic transmission. In the first preferred embodiment, a downshift operation of the automatic transmission is detected. In the second preferred embodiment, an overrun clutch solenoid is turned on (energized). In the latter case, both fuel supply recovery and fuel supply cut-off engine revolution speeds are set to higher values than those when the clutch solenoid is turned off (deenergized).

Abstract: In the event of a sensor malfunction, a fail safe arrangement either modifies or inhibits controls which are intended to reduce shift shock and/or friction element slippage and which adjust either the level of line pressure or vary the torque generated by the prime mover during shifts.

Abstract: A hydraulic pressure, i.e., a line pressure, of a hydraulic fluid supplied from an engine driven pump toward a hydraulically actuable coupling of an automatic transmission is held at the maximum pressure value when a temperature of an automatic transmission oil is less than a predetermined temperature value. However, the hydraulic pressure is temporarily decreased from the maximum pressure value to the minimum pressure value for a period of time after cranking of the engine when the transmission oil temperature is lower than the predetermined temperature value. Owing to a decreased load on the engine by the oil pump, smooth cranking and subsequent warming-up operation of the engine is assured under cold whether condition when the automatic transmission oil temperature is lower than the predetermined temperature value.

Abstract: In order to determine a malfunction which results in the loss of torque reduction control, the engine speed and the torque converter characteristics are monitored when a torque down signal is issued. The maximum engine torque which should be produced under such circumstances is used to derive a corresponding maximum engine speed value. If the actual engine speed exceeds the estimated value, appropriate torque down control can be assumed to have been lost. In response a fail safe such as boosting line pressure to switching to an alternative source of torque control can implemented. A suitable warning signal can also be generated.

Abstract: For a predetermined period following the issuance of a shift command signal, the output of a engine speed signal is temporarily ignored. Upon the expiration of the predetermined time, the engine speed is sampled and if the rate of change thereof is above a given value, the initiation of the shift operation is deemed to have occurred.

Abstract: A unified control device for engine and automatic transmission of an automotive vehicles serves to alleviate a racing select shock which occurs upon engagement of a driving clutch in the transmission when selecting a running range of the transmission to start the vehicle with an accelerator pedal depressed. The control device achieves a reduction control during changeover of the transmission into a running range from a racing state, to reduce at least one parameter representing the output power to be transmitted from the engine to driving wheels via the transmission, such as engine speed, engine output and/or transfer torque capacity of the clutch, etc. The reduction control is stopped as soon as the completion of engagement of the driving clutch has been detected, to allow the vehicle to be started without engine stalling.

Abstract: A period time required for a gear shift operation is measured from the time at which a prime motor output speed starts decreasing to the time at which a psuedo speed ratio reaches a predetermined value. Based on the period of time measured, a line pressure is controlled during the period of time. Alternatively, a prime motor output torque is controlled during the period of time measured.

Abstract: A power train control system includes circuitry which, during the delay between the issuance of a shift command signal and the actual initiation of shift and/or during non-shifting modes of operation, monitors the outputs of sensors. If the sensors are found to be out of order, steps are subsequently taken to inhibit prime mover torque variation so as to avoid erroneous shock attenation control. The line pressure is controlled in accordance with the presence or absence of a torque variation signal to provide an improved match between the engine torque and transmission line pressure controls.

Abstract: A number of parameters representative of the vehicle operation are sampled in addition to those critical for determining the actual malfunction of the turbine sensor. In the event that the additionally sensed parameters are such as to indicate that conditions exist under which an erroneous malfunction detection is apt to occur, the diagnostic process is inhibited or alternatively, in the event that a malfunction is detected under such conditions, the malfunction indication is ignored and neither recorded in memory nor displayed.

Abstract: The outputs of one or more the sensors involved in the control of the transmission line pressure level are monitored. In the event that one of the same exhibits characteristics indicative that it is malfunctioning, a self-update function which modifies the line pressure level based on the length of a shift time is inhibited in order to prevent the line pressure being adjusted in a totally erroneous manner.

Abstract: A line pressure control arrangement includes a self-adjust function which prevents the updating of the line pressure control during no-load shifts or uses different target times for no-load (power off) and positive load (power on) shifts.