Abstract: A four-wheel drive vehicle in which the engine output is transmitted to front wheels and to rear wheel through a transfer clutch. The control unit determines a road gradient from the output value of a longitudinal acceleration sensor at a stop, sets a lower limit on the basis of the road gradient and is prepared for a start by outputting a drive signal corresponding to lower limit to a clutch control valve for controlling the applying force of the transfer clutch. Thus, the applying force is set according to the road gradient so that the main drive wheels at the slope can be prevented from slipping by the minimum transmission torque.

Abstract: A power distribution control system for a vehicle, in which a front/rear drive-force distribution control unit computes a torque-response-torque, a revolution-difference-response-torque and a yaw-rate feed back torque. When a torque down command by a traction control is not outputted to an engine control unit, and a braking force control is not active, a transfer clutch torque is setted as defined by a predetermined equation.

Abstract: A four-wheel drive vehicle in which the engine output is transmitted to front wheels and to rear wheel through a transfer clutch. The control unit determines a road gradient from the output value of a longitudinal acceleration sensor at a stop, sets a lower limit on the basis of the road gradient and is prepared for a start by outputting a drive signal corresponding to lower limit to a clutch control valve for controlling the applying force of the transfer clutch. Thus, the applying force is set according to the road gradient so that the main drive wheels at the slope can be prevented from slipping by the minimum transmission torque.

Abstract: A four-wheel drive vehicle in which the engine output is transmitted to front wheels and to rear wheel through a transfer clutch. The control unit determines a road gradient from the output value of a longitudinal acceleration sensor at a stop, sets a lower limit on the basis of the road gradient and is prepared for a start by outputting a drive signal corresponding to lower limit to a clutch control valve for controlling the applying force of the transfer clutch. Thus, the applying force is set according to the road gradient so that the main drive wheels at the slope can be prevented from slipping by the minimum transmission torque.

Abstract: In case there occurs a wheel slip in either one of front left and right wheels or rear left and right wheels, a traction control through an engine output and a traction control through braking are implemented. Furthermore, in case the vehicle speed is slow, a final limited slip differential torque is set by adding a limited slip differential compensation amount according to a steering angle to a limited slip differential torque set according to an inputted torque and a front/rear differential rotation, and further adding thereto a limited slip differential compensation amount according to the vehicle speed for increasing the compensation.

Abstract: In case there occurs a wheel slip in either one of front left and right wheels or rear left and right wheels, a traction control through an engine output and a traction control through braking are implemented. Furthermore, in case the vehicle speed is slow, a final limited slip differential torque is set by adding a limited slip differential compensation amount according to a steering angle to a limited slip differential torque set according to an inputted torque and a front/rear differential rotation, and further adding thereto a limited slip differential compensation amount according to the vehicle speed for increasing the compensation.

Abstract: A power distribution control system for a vehicle, in which a front/rear drive-force distribution control unit computes a torque-response-torque, a revolution-difference-response-torque and a yaw-rate feed back torque. When a torque down command by a traction control is not outputted to an engine control unit, and a braking force control is not active, a transfer clutch torque is setted as defined by a predetermined equation.

Abstract: A four-wheel drive vehicle in which the engine output is transmitted to front wheels and to rear wheel through a transfer clutch. The control unit determines a road gradient from the output value of a longitudinal acceleration sensor at a stop, sets a lower limit on the basis of the road gradient and is prepared for a start by outputting a drive signal corresponding to lower limit to a clutch control valve for controlling the applying force of the transfer clutch. Thus, the applying force is set according to the road gradient so that the main drive wheels at the slope can be prevented from slipping by the minimum transmission torque.

Abstract: A control system of a vehicular continuously variable transmission having a manual transmission mode comprises speed ratio changing when a manual transmission mode is chosen and a speed range is manually selected for changing a speed ratio of the selected speed range in the up-shift direction as the engine speed becomes high on the side of low speed ranges and in the down-shift direction as the vehicle speed becomes high on the side of high speed ranges. Further, in the manual transmission mode, when the engine speed reaches a lower limit value without making a down-shift, the speed ratio is controlled so as to hold the engine speed at the lower limit value. Thus constituted continuously variable transmission provides a vehicle with miscellaneous advantages such as an easy handling, smooth acceleration/deceleration performance, extended maximum speed and the like when the manual transmission mode is selected.

Abstract: A failure detecting method and apparatus for an automatic transmission of a vehicle having a vehicle speed sensor mounted on said vehicle for sensing a vehicle speed and an inhibitor switch attached on said automatic transmission for detecting a gear shift range position, The method is carried out by judging whether the vehicle speed is larger than a predetermined value; checking whether a neutral range position is detected; detecting whether another gear shift range position is absent after a predetermined time has lapsed; and then controlling the automatic transmission as if the gear shift range position is in a drive range. This enables one to precisely detect a failure of the range signal line and to control the automatic transmission in an optimum condition under any driving conditions.

Abstract: A sensor failure and erroneous signal detection system for use in automobiles equipped with cruise control. This system prevents cruise control from operating if certain predetermined conditions occur. Further, the system will determine if the cruise control signal has been erroneously generated and set up an error "flag". A failure is determined in the cruise control system if either one of the following conditions is present when a cruise control signal is generated: (1) the vehicle is traveling below a predetermined speed; (2) the brake switch is on; (2) the shift range is in "N", "R" or "P"; or (4) either (1), (2) or (3) continues for a predetermined period of time. Upon occurrence of (1), (2), (3), or (4), an error has been detected and the automatic transmission is instructed to return to normal operation.

Abstract: A method and system for detecting a failure of an automatic transmission for a vehicle employing a speed shift range switch operation signal from a speed shift range switch as one of the control signals to control the automatic transmission. The method is carried out by: detecting a speed shift range from the speed shift range switch; generating a start signal indicating a starting state of a starter for expediting a start of an engine for the vehicle; and automatically controlling the automatic transmission so as to maintain the speed shift range in the case where "P" or "N" range is not detected when the start signal is "ON".

Abstract: In case where an engine rotational detection signal from an ignition pulse generator is not appropriately detected even if an amount of induction air and a fuel injection amount are larger than predetermined values, an engine rotational signal failure is decided, and an automatic transmission is controlled in a state before the decision. Therefore, the automatic transmission control based on the engine rotational speed such as, for example, a speed shift control (ordinarily a shift control), a lockup control (ordinarily a lockup control, a smooth control), a line pressure control (ordinarily a line pressure control, a starting time control) can be appropriately controlled. Thus, the automatic transmission control can be executed based on the engine rotational speed.

Abstract: A failure detecting system for an automatic transmission of a vehicle is disclosed. The system can be controlled by the engine rotation speed, cruise control signal, a brake signal from a brake switch, or a shift range switch operation signal from a shift range switch.

Abstract: A motor vehicle has an antilock brake system which is provided for preventing wheels from locking, and an automatic transmission of the vehicle has a one-way clutch for transmitting the output of an engine of the vehicle to wheels of the vehicle at acceleration of the engine, and a clutch for transmitting torque from the wheels to the engine, thereby effecting engine braking. A detector is provided for detecting operation of the antilock brake system and for producing a signal. In response to the signal, the clutch is released, thereby rendering the engine braking ineffective.

Abstract: A system for controlling clutch current of an electromagnetic clutch at acceleration of a vehicle on a downhill. The clutch is engaged when vehicle speed is higher than a first reference speed. When the vehicle is accelerated on a downhill at a speed higher than a second reference speed which is lower than the first reference speed, the clutch is engaged to provide an engine braking effect.

Abstract: A system for controlling a drag torque of an electromagnetic clutch at idling operation of an engine for a motor vehicle with a continuously variable belt drive transmission. A detector is provided for detecting whether engine speed is higher or lower than a predetermined minimum idling speed. When the engine speed is at a higher engine speed, a standard current is passed in a coil of the clutch. At a lower idling speed, the drag current is gradually reduced until the engine speed increases to the predetermined minimum idling speed.

Abstract: A system for controlling a drag torque of an electromagnetic clutch at releasing of an accelerator pedal of a motor vehicle with a continuously variable belt drive transmission. A detector is provided for detecting whether vehicle speed is lower than a predetermined low speed. At the low vehicle speed, the drag current is gradually reduced as the vehicle speed increases.

Abstract: A power transmission system for a four-wheel drive vehicle has an automatic transmission for transmitting power of an engine to main driving wheels and a transfer clutch for transmitting the power to auxiliary driving wheels. First and second vehicle speed sensors are provided for sensing vehicle speed dependent on the main driving wheels and the auxiliary driving wheels, respectively. A two-wheel drive switch is provided for producing a two-wheel drive signal. The automatic transmission uses an output signal of the first vehicle speed sensor as data representing driving conditions of the vehicle. In response to the two-wheel drive signal, the transfer clutch is disengaged and an output signal of the second vehicle speed sensor is selected as vehicle speed.

Abstract: A system for disengaging an electromagnetic clutch of a vehicle at rapid deceleration of the vehicle. The rapid deceleration is detected by changing rate of engine speed when the magnitude of deceleration is larger than a reference value, the electromagnetic clutch is disengaged at an engine speed which is higher than idling speed.