Abstract: An automatic transmission comprises a metal V-belt mechanism 10, which changes the speed ratio of the rotational output from an engine ENG, a forward/reverse direction change mechanism 20, which switches the rotational direction of the ratio-change mechanism, and a forward clutch 30, which actuates the switching operation of the rotational direction performed by the forward/reverse direction-change mechanism. A control system for this transmission comprises a regulator valve 50, which generates a line pressure, a manual valve 80, which is operated in correspondence to the shift lever and switches the supply of the line pressure to the forward clutch, and a drive-range sensor 105, which detects the operation of the manual valve. When the movement of the manual valve to a position where the line pressure is to be supplied to the forward clutch is detected by the drive-range sensor 105, the line pressure, which is adjusted by the regulator valve, is lowered for a predetermined time period.

Abstract: A flywheel device for a prime mover can be made compact in axial size and has an effectively increased inertial mass. The flywheel device includes a drive plate and a mass ring. The drive plate has an annular projection and is attached to a crankshaft concentric with the crankshaft. The mass ring has an annular recess and is concentrically attached to the drive plate by the annular recess being fitted on the annular projection of the drive plate. The flywheel device transmits torque from an engine as the prime mover to the input shaft of an automatic transmission while reducing variation in the torque.

Abstract: An automatic transmission comprises a metal V-belt mechanism 10, which changes the speed ratio of the rotational output from an engine ENG, a forward/reverse direction change mechanism 20, which switches the rotational direction of the ratio-change mechanism, and a forward clutch 30, which actuates the switching operation of the rotational direction performed by the forward/reverse direction-change mechanism. A control system for this transmission comprises a regulator valve 50, which generates a line pressure, a manual valve 80, which is operated in correspondence to the shift lever and switches the supply of the line pressure to the forward clutch, and a drive-range sensor 105, which detects the operation of the manual valve. When the movement of the manual valve to a position where the line pressure is to be supplied to the forward clutch is detected by the drive-range sensor 105, the line pressure, which is adjusted by the regulator valve, is lowered for a predetermined time period.

Abstract: When a road surface gradient is calculated by a wheel driving force and a vehicle acceleration, if the wheel driving force is calculated based on an output torque of an engine, the accuracy of calculating the wheel driving force, i.e., the road surface gradient becomes poor due to deterioration by aging of the engine or the like. In order to solve this kind of disadvantage, a fluid transmission torque of a torque converter is calculated by those torque ratio of the torque converter and an input shaft torque coefficient which correspond to a speed ratio of the torque converter, and an input rotational speed of the torque converter (=engine rotational speed (step S21-3). The road surface gradient is calculated by using a wheel driving force to be calculated by this torque.

Abstract: When a starter clutch slips, a wheel driving force is calculated based on a transmitting torque of the clutch obtained from not an engine torque but the clutch pressure (engagement force) of the starter clutch (S21-12), whereby a road gradient is calculated using the driving force so calculated and an acceleration of a vehicle.

Abstract: There is provided a flywheel device for a prime mover, which can be made compact in the axial size thereof and have an effectively increased inertial mass. The flywheel device is comprised of a drive plate and a mass ring. The drive plate has an annular projection and is attached to a crankshaft in a manner concentric with the crankshaft. The mass ring has an annular recess and is concentrically attached to the drive plate by the annular recess being fitted on the annular projection of the drive plate. The flywheel device transmits torque from an engine as the prime mover to the input shaft of an automatic transmission while reducing variation in the torque.

Abstract: When a starter clutch slips, a wheel driving force is calculated based on a transmitting torque of the clutch obtained from not an engine torque but the clutch pressure (engagement force) of the starter clutch (S21-12), whereby a road gradient is calculated using the driving force so calculated and an acceleration of a vehicle.

Abstract: Drive and driven pulley necessary axial thrusts (Qdrnec, Qdnnec) necessary for power transmission without belt slippage are found in accordance with the input torque and transmission ratio; the vehicle speed and degree of accelerator opening target transmission ratio (itgt) and target rate of change of transmission ratio (ditgt) are found; this axial thrust (Qdnnec) is set as the driven pulley target axial thrust (Qdncmd); and the drive pulley axial thrust necessary to obtain the target values (itgt) and (ditgt) is set as the drive pulley target axial thrust (Qdrcmd). Then, if (Qdrcmd)<(Qdrnec), this axial thrust (Qdrnec) is altered and set as the drive pulley target axial thrust (Qdrcmd) and the driven axial thrust necessary for obtaining the target values (itgt), (ditgt) is altered and set as the driven pulley target axial thrust (Qdncmd). Drive and driven pulley axial thrust control is performed such that these target axial thrusts (Qdrcmd, Qdncmd) are obtained.