Abstract: A hydraulic pressure of each corresponding one of a plurality of friction elements of a gear shift mechanism of the automatic transmission is controlled to downshift the gear shift mechanism from a current gear stage to a next gear stage, at which an engine brake is operated, upon receiving a driver's demand for deceleration. An engine output of the engine is increased by increasing a throttle opening degree of the engine in at least two steps in an absence of a driver's operation on an accelerator of the vehicle at the time of the downshifting of the gear shift mechanism from the current gear stage to the next gear stage.

Abstract: A vehicle speed memory unit stores a vehicle speed at a prior predetermined time, the vehicle speed being calculated from an interval of the vehicle speed pulse. A first rapid deceleration detecting section compares an elapsed time from a time the vehicle speed pulse signal is inputted, measured by an elapsed time measuring unit, with a pulse interval corresponding to a predetermined deceleration relative to a vehicle speed stored by the vehicle speed memory unit, or a second rapid deceleration detecting section calculates an undetermined vehicle speed from the elapsed time measured by the elapsed time measuring unit, and calculates a deceleration from the undetermined vehicle speed and the vehicle speed at the prior predetermined time, and compares the calculated deceleration with a predetermined deceleration threshold value. Thus, rapid vehicle deceleration can immediately be determined at the present time without waiting for the determination of the vehicle speed after input of the next pulse signal.

Abstract: An automotive automatic transmission control system is provided which is designed to increase the output of an engine in response to a driver's request to downshift a transmission for setting up the engine braking and to load the amount of working fluid to an on-coming clutch quickly during the downshift. The system works to determine whether the loaded amount of working fluid is excessive or lacking using the speeds of an input shaft of the transmission and the engine to correct the amount of working fluid to be used upon a subsequent downshift request. The use of the two speeds enables the fact that the loaded fluid amount is excessive which arises from a rise in the speed of the input shaft caused by the engine output increasing control, not by completion of the loading of the working fluid to the on-coming clutch to be found accurately.

Abstract: In executing an ETC cooperative downshift operation based on a driver's intent to decelerate, this system executes an engine output increasing control (e.g. a combination of a throttle opening control and a fuel injection restoring control) for increasing the engine output irrespective of driver's accelerator operation. At the timing a reduction amount in an input shaft rotational speed Nt exceeds a predetermined value K after the ETC cooperative downshift control is started, it is presumed that the hydraulic pressure of a to-be-disengaged clutch is already reduced to a hydraulic pressure level equivalent to a predetermined transmission torque capacity that causes no undesirable acceleration or shock even if the engine output increasing control is started. And, under such assumption, the engine output increasing control is started at this timing.

Abstract: An automotive automatic transmission control apparatus is provided which works to increase the power of an engine in response to a request to down-shift the gear of an automatic transmission for developing the engine braking. The control apparatus includes a fail-safe circuit working to stop increasing the power of the engine when a defect in operation of a transmission hydraulic control circuit is detected after the hydraulic control circuit starts to control the hydraulic pressures to achieve the downshift of the automatic transmission. This eliminates or alleviates a problem, such as unwanted acceleration of the vehicle during the control of the downshift in the transmission.

Abstract: In a lockup control system of an automatic transmission with a lockup torque converter, a controller pre-stores a predetermined lockup control map including at least a predetermined coast slip lockup area, within which the system executes a slip lockup control mode under the vehicle's coasting condition, so that a speed difference between input and output speeds of the torque converter is brought closer to a predetermined value. The controller determines whether a first transition from the vehicle's driving condition to the predetermined coast slip lockup area occurs in a release mode of the lockup clutch or a second transition from the vehicle's coasting condition to the predetermined coast slip lockup area occurs in the release mode. When the first transition occurs, the lockup clutch is conditioned in the slip lockup control mode. When the second transition occurs, the lockup clutch is conditioned in the release mode.

Abstract: A vehicle speed memory unit stores a vehicle speed at a prior predetermined time, the vehicle speed being calculated from an interval of the vehicle speed pulse. A first rapid deceleration detecting section compares an elapsed time from a time the vehicle speed pulse signal is inputted, measured by an elapsed time measuring unit, with a pulse interval corresponding to a predetermined deceleration relative to a vehicle speed stored by the vehicle speed memory unit, or a second rapid deceleration detecting section calculates an undetermined vehicle speed from the elapsed time measured by the elapsed time measuring unit, and calculates a deceleration from the undetermined vehicle speed and the vehicle speed at the prior predetermined time, and compares the calculated deceleration with a predetermined deceleration threshold value. Thus, rapid vehicle deceleration can immediately be determined at the present time without waiting for the determination of the vehicle speed after input of the next pulse signal.

Abstract: In a lockup control system of an automatic transmission with a lockup torque converter, a controller pre-stores a predetermined lockup control map including at least a predetermined coast slip lockup area, within which the system executes a slip lockup control mode under the vehicle's coasting condition, so that a speed difference between input and output speeds of the torque converter is brought closer to a predetermined value. The controller determines whether a first transition from the vehicle's driving condition to the predetermined coast slip lockup area occurs in a release mode of the lockup clutch or a second transition from the vehicle's coasting condition to the predetermined coast slip lockup area occurs in the release mode. When the first transition occurs, the lockup clutch is conditioned in the slip lockup control mode. When the second transition occurs, the lockup clutch is conditioned in the release mode.