Abstract: A control device for controlling a continuously variable transmission (5) is disclosed. The control device has an oil pressure control unit (100) which supplies an oil pressure to a primary pulley (10) and secondary pulley (11) based on a command signal indicative of a target speed-reduction ratio, a sensor (26) which detects a rotation speed (Np1) of the primary pulley (26), and a controller (20) which transmits the command signal indicative of the target speed-reduction ratio to the oil pressure control unit (100).

Abstract: There are provided with a determination means for determining whether or not the correlation between the pressure value detected by the primary pressure sensor and the pressure value detected by the secondary pressure sensor is an actually impossible relation (Step 5), and a switchover means for switching over to an open control while prohibiting a feedback control when the correlation is determined to have become a relation actually impossible by the determination means (Step 6). Presence or absence of a fault to the primary pressure sensor or the secondary pressure sensor (particularly, fault of fixed output voltage) is judged based on the correlation between the output voltage of the primary pressure sensor and the output voltage of the secondary pressure sensor to prohibit the control of a primary pressure and a secondary pressure using the hydraulic pressure sensors when it is judged that there is a fault.

Abstract: In a system for controlling an automatic transmission, at the time of ultra-low temperature start with the oil temperature of ?20° C. or less, control is carried out such that when the state that the actual line pressure is equal to or greater than an ultra-low set value continues for a period longer than a line-pressure low-pressure control command set time, it is determined that the line pressure is under regulation, maximizing an indicated value of the line pressure.

Abstract: A hydraulic clutch transmits driving torque in a power train of a vehicle. An oil pressure supply unit supplies oil pressure for engagement to the clutch and a controller controls the unit. The controller causes the unit, prior to engagement of the clutch, to precharge the interior of the clutch with hydraulic fluid. The controller counts an elapsed time since the last release of the clutch and shortens the precharge period as the elapsed time decreases, thereby optimizing the precharge state of the clutch.

Abstract: A speed change ratio control unit for a continuously variable transmission that uses a step motor as a driving actuator of a speed change control valve that compares a variable ASTP representing a step position of the step motor and a step position BSTP of the step motor that is necessary for realizing a desired speed change ratio at every predetermined operation cycle, and if ASTP?BSTP is satisfied determines that a step-out has occurred on the step motor.

Abstract: An oil pressure control device, which changes a range of a vehicle transmission includes: a pressure adjusting device that engages or releases forward and reverse frictional-engagement devices by adjusting an oil pressure supply, a sensor that detects a range selected by a vehicle driver, and a controller that controls the clutch pressure adjusting device based on a signal from the sensor. When the stop range is selected after selecting the reverse (forward) range, a forward (reverse) range is selected. After supplying an initial oil pressure to the forward (reverse) frictional-engagement device, the pressure adjusting device is controlled so that the pressure decreases from the initial oil pressure to a predetermined oil pressure. Subsequently, the oil pressure is initially increased at a small increase rate from the predetermined oil pressure. After a predetermined time period has elapsed, the pressure adjusting device increases the oil pressure at a large increase rate.

Abstract: There are provided with a determination means for determining whether or not the correlation between the pressure value detected by the primary pressure sensor and the pressure value detected by the secondary pressure sensor is an actually impossible relation (Step 5), and a switchover means for switching over to an open control while prohibiting a feedback control when the correlation is determined to have become a relation actually impossible by the determination means (Step 6). Presence or absence of a fault to the primary pressure sensor or the secondary pressure sensor (particularly, fault of fixed output voltage) is judged based on the correlation between the output voltage of the primary pressure sensor and the output voltage of the secondary pressure sensor to prohibit the control of a primary pressure and a secondary pressure using the hydraulic pressure sensors when it is judged that there is a fault.

Abstract: Disclosed is a control device for controlling a two-way linear solenoid valve (60) including a pressure regulating port (60p) which communicates with a hydraulic circuit side, a drain port (60d) which communicates with a drain side, a plunger (61) which controls the state of communication between the pressure regulating port and drain port, and a coil (70) which drives the plunger in accordance with an exciting current. The control device has a current generator (65) which supplies the coil with the exciting current corresponding to a duty signal; and a microcomputer (1). The microcomputer determines whether or not a preset foreign matter removal starting condition for removing foreign matter accumulated in the ports has been established.

Abstract: A control device for controlling a continuously variable transmission (5) is disclosed. The control device has an oil pressure control unit (100) which supplies an oil pressure to a primary pulley (10) and secondary pulley (11) based on a command signal indicative of a target speed-reduction ratio, a sensor (26) which detects a rotation speed (Np1) of the primary pulley (26), and a controller (20) which transmits the command signal indicative of the target speed-reduction ratio to the oil pressure control unit (100).

Abstract: Disclosed is a control device for controlling a two-way linear solenoid valve (60) including a pressure regulating port (60p) which communicates with a hydraulic circuit side, a drain port (60d) which communicates with a drain side, a plunger (61) which controls the state of communication between the pressure regulating port and drain port, and a coil (70) which drives the plunger in accordance with an exciting current. The control device has a current generator (65) which supplies the coil with the exciting current corresponding to a duty signal; and a microcomputer (1). The microcomputer determines whether or not a preset foreign matter removal starting condition for removing foreign matter accumulated in the ports has been established.

Abstract: An oil pressure control device which changes the operating range of a vehicle transmission has a clutch pressure adjusting device which engages or releases a forward clutch and reverse clutch by adjusting the supply of oil pressure, a sensor which detects the operating range selected by a driver of the vehicle, and a controller which controls the clutch pressure adjusting device based on a signal from the sensor. When the stop range has been selected after selecting the reverse (forward) range, and a forward (reverse) range is then selected, after precharge has been performed to supply an initial oil pressure to the forward (reverse) clutch, the clutch pressure adjusting device is controlled so that the pressure decreases from the initial oil pressure to a predetermined oil pressure.

Abstract: A hydraulic clutch (12, 13) transmits driving torque in a power train of a vehicle. An oil pressure supply unit (35) which supplies oil pressure for engagement to the clutch (12, 13) and a controller (40) which controls the unit (35) are provided. The controller (40) causes the unit (35) prior to engagement of the clutch (12, 13) to precharge the interior of the clutch (12, 13) with hydraulic fluid. The controller (40) counts an elapsed time since the last release of the clutch (12, 13) and shortens the precharge period as the elapsed time decreases, thereby optimizing the precharge state of the clutch (12, 13).

Abstract: A speed change ratio control unit for a continuously variable transmission that uses a step motor as a driving actuator of a speed change control valve comprising a step-out determination means that compares a variable (ASTP) representing a step position of the step motor and a step position (BSTP) of the step motor that is necessary for realizing a desired speed change ratio at every predetermined operation cycle, and if ASTP≠BSTP is satisfied determines that a step-out has occurred on the step motor; a step-out correction means (S17d,S17f) that when a step-out is determined by the step-out determination means (S17b) corrects the ASTP so as to reduce a difference between the ASTP and the BSTP; and a drive means for driving the step motor using the corrected ASTP. The speed change ratio control unit for a continuously variable transmission is provided that can detect and correct a step-out at any speed change ratio.

Abstract: In a system for controlling an automatic transmission, at the time of ultra-low temperature start with the oil temperature of −20° C. or less, control is carried out such that when the state that the actual line pressure is equal to or greater than an ultra-low set value continues for a period longer than a line-pressure low-pressure control command set time, it is determined that the line pressure is under regulation, maximizing an indicated value of the line pressure.

Abstract: After an engine (1) has started, a controller (6) starts determining whether lockup should be prohibited or permitted based on the cooling water temperature of an engine (1) or the oil temperature of a transmission (2). Once it has been determined that lockup should be permitted, the controller (6) stops determining whether lockup should be prohibited or permitted until the next time the engine (1) is started. In this way, once the conditions for determining that lockup should be permitted hold, lockup prohibition or permission based on the engine cooling water temperature or transmission oil temperature is no longer determined, so repeat engaging and disengaging of the lockup clutch (5) due to fluctuations of engine cooling water temperature or transmission oil temperature, is prevented.

Abstract: An electronic transmission control system having a fail-safe system for an automotive vehicle with a continuously variable automatic transmission whose speed-change ratio is changeable continuously depending on vehicle speed and engine load, comprises a hydraulic modulator producing at least a regulated line pressure necessary to adjust the speed-change ratio hydraulically, a desired speed-change ratio arithmetic processing section for calculating a desired speed-change ratio based on the vehicle speed and the engine load, and a desired line pressure arithmetic processing section for calculating a desired line pressure based on the desired speed-change ratio and the engine load.

Abstract: Described are apparatus and method for monitoring revolution speed values detected by corresponding revolution speed sensors too determine whether at least any one of an engine revolution speed sensor, a continuously variable transmission input axle revolution speed sensor, and a continuously variable transmission output axle revolution speed sensor has failed according to detected values of the engine revolution speed sensor, the input axle revolution speed sensor, and the output axle revolution speed sensor and a detected value of an instantaneous gear shift ratio when a lock-up mechanism is in a lock-up state. If all of three formulae on predetermined correlations are established, all of the sensors are determined to be normally operated. If any one or two of the three formulae are not established, the failure one of the three sensors is identified. The three correlation formulae are based as follows: 1) N.sub.E =N.sub.PRI ; 2) N.sub.PRI =N.sub.SEC .times.CN; and 3) N.sub.E =N.sub.PRI .times.C.sub.

Abstract: A positional determination device which is drived according to the pulse signals output to a stepping motor 1 and displaces a nut 2 to a position corresponding to the degree of rotation. In order to adjust the initializing position of a feed mechanism, the stepping motor 1 is rotated and the nut 2 displaces until it reaches the limiting position (LimA) defined by the stopper 3a. When initializing, the pattern of temporarily stopping the stepping motor 1 for a period corresponding to a pulse number (N2) at each pulse number (N1) and rotating is repeated. As a result the rotations of the stepping motor 1 become gentle and even if the nut 2 were to collide with the stopper 3a at the limiting position, the reverse rotation of the stepping motor 1 can be prevented and accurate adjustment of the initializing device can be performed.

Abstract: A method of controlling automatic transmissions during traction control for reducing engine output upon occurrence of a skid of a driving wheel comprises moving in a high throttle valve opening area a predetermined shift line on the low vehicular speed side, and moving the predetermined shift line on the high vehicular speed side in a low throttle valve opening area.

Abstract: In a controller which controls a speed change ratio of a continuously variable transmission to a target speed change ratio set based on the driving conditions of an automobile, the driver manually inputs a command which increases or decreases the speed change ratio. The controller increases or decreases the target speed change ratio by a predetermined amount according to this command. Preferably, this increase/decrease pattern is varied according to the time for which the command continues. The driver of the automobile can thereby achieve a desired speed change ratio by a simple operation.