Abstract: A method is provided for the control of the state of engagement of a damper clutch arranged in association with a vehicle engine, which has a fuel cut mechanism for suspending a supply of fuel during a decelerated operation, to permit connection between an input member and an output member in a torque converter arranged on an output side of the engine. Upon detection of a decelerated operation of the engine, the damper clutch is controlled to bring the input member and output member into a desired state of engagement. Here, the damper clutch is first released for a predetermined time and is then moved to an engaged side. Next, the damper clutch is feedback-controlled into a desired slip state so that the input member and the output member are allowed to rotate with a desired difference in revolution speed therebetween. A system for practicing the method is also described.

Abstract: A control method is provided for an engine for a vehicle. The engine is arranged in association with a fluid coupling having a clutch. According to the control method, the state of engagement of the clutch is first detected. In the next step, it is determined whether or not the vehicle is in a predetermined decelerated operation state. When the clutch has been detected to be in a predetermined state of engagement in the clutch engagement state detection step and in addition, the vehicle has been determined to be in the predetermined decelerated operation state in the decelerated operation state determination step, an output of the engine is increased in the subsequent step.

Abstract: This invention relates to a fault diagnosis apparatus for a vehicle control system. The fault diagnosis apparatus is useful in diagnosing a fault of an electronic component mounted on a vehicle, especially when the fault has led to such a control as deteriorating exhaust gas. It is an object of this invention to minimize an increase in the manufacturing cost upon incorporation of such a fault diagnosis apparatus. According to this invention, the vehicle control system has an automatic transmission operation state detection sensor, an engine operation state detection sensor, an automatic transmission control unit and an engine control unit. For the diagnosis of a fault of at least one of the sensors and control units, the fault diagnosis apparatus comprises a fault determining unit, a code converter, a fault determining unit, a code converter, an ISO converter and a determining and diagnosing tester.

Abstract: A power transmission apparatus suitable for use with a four wheel drive apparatus of an automobile which can prevent production of rattling noises of a driving system and occurrence of a swerving phenomenon of the automobile. The apparatus includes a cam ring connected to a first rotary shaft and a rotor connected to a second rotary shaft and accommodated for rotation in the cam ring to define a pump chamber therebetween and is designed to transmit driving force between the first and second rotary shafts in accordance with a pressure of working fluid in the pump chamber which is produced in response to rotation of the first and second rotary shafts relative to each other. The apparatus comprises a frictional force applying mechanism interposed between the first and second rotary shafts for applying predetermined frictional force between them to assure stabilized transmission of torque between the first and second rotary shaft.

Abstract: A power transmission apparatus suitable for use with a four wheel drive apparatus of an automobile which can prevent spouting of working fluid through a sealing portion or the like and introduction of external air into the apparatus through a sealing portion. The apparatus comprises a hydraulic transmission coupling mechanism of the vane pump type connected to a pair of shafts to transmit driving force between the shafts and having a pump chamber formed therein. A tank is provided in an integral relationship with the coupling mechanism and accommodates working fluid in an enclosed condition therein. A volume variation absorbing mechanism is provided near an axis of rotation of the coupling mechanism for absorbing a variation in volume of the working fluid in the pump chamber.

Abstract: In a drive coupling unit suitable for use in an four-wheel drive unit for motor vehicles of the type wherein a torque is transmitted via a fluid pressure produced depending on a difference in rotational speed between two rotating shafts, each working fluid supply passage and a corresponding check valve disposed therein are arranged to interconnect one of two intake/discharge ports in each respective pump chamber with a tank in which a working fluid is retained. With this construction, an improved response characteristic of the check valves and a substantial reduction of the overall size of the drive coupling unit can be attained.

Abstract: A power transmission includes two piston-type actuators for selectively engaging and releasing their associated clutches. Each of the actuators is designed in such a way that in order to compensate a centrifugal hydraulic pressure to be developed in a working fluid chamber by a remaining hydraulic fluid upon release of the clutch, a centrifugal hydraulic pressure chamber is formed on the side opposite to the working fluid chamber relative to a piston and a centrifugal hydraulic pressure equal to the centrifugal hydraulic pressure in the working fluid chamber is produced in the centrifugal hydraulic pressure chamber. A partition forming the centrifugal hydraulic pressure chamber also serves as a cylinder forming the working fluid chamber of the other actuator.

Abstract: A differential capable of distributing a torque of the input shaft to the two output shaft thereof and equipped with a differential motion limiting mechanism. The differential comprises a differential mechanism which receives a driving force through the input shaft thereof from a transmission connected to an engine and distributes the driving force to two output shafts; an oil pump interposed between two shafts, namely, the input shaft and either one of the output shafts themselves, and adapted to be driven by a differential revolving speed between the two shafts so as to produce a discharge pressure corresponding to the differential revolving speed; a clutch mechanism for coupling the two shafts; a hydraulic circuit for supplying the discharge pressure of the oil pump to the clutch mechanism to engage the two shafts; and hydraulic control means provided in the hydraulic circuit to control the discharge pressure to be supplied to the clutch mechanism.

Abstract: The present invention relates to a power transmission system for a vehicle of the type in which front and rear wheels are driven by a sole engine. In order to control the distribution of drive torque produced by the engine to front wheel side and rear wheel side of the vehicle according to a difference in rotational speed between both sides and in relative rotational direction between both sides, the power transmission system includes an oil pump adapted to be driven by a first rotational shaft which transmits a driving torque from an engine to front wheels of the vehicle and a second rotational shaft which transmits the driving force to rear wheels of the vehicle. The oil pump produces an oil pressure proportional to the difference in rotational speed and has at least two ports. A clutch mechanism couples the rotational shafts with each other by the discharge pressure of the oil pump and, the clutch mechanism is disposed between the rotational shafts.

Abstract: In a power transmission apparatus for use in a vehicle of the type in which its front and rear wheels are driven by the same engine, a first rotary shaft transmitting drive force to the front wheels and a second rotary shaft transmitting drive force to the rear wheels are coupled to each other through a hydraulic oil pump which is driven according to the rotation speed difference between the first and second rotary shafts and delivers hydraulic oil of an amount corresponding to the rotation speed difference. The pressure of hydraulic oil delivered from the pump is controlled by hydraulic control means so as to automatically change over between the two-wheel drive mode in which the front or rear wheels only are driven and the four-wheel drive mode in which both the front and rear wheels are driven.

Abstract: An automatic transmission for a vehicle change-speed gear mechanism connected to an output shaft of a hydro-dynamic power transmitting device, and a clutch capable of connecting the input and output shafts of the hydro-dynamic power transmitting device, a drop in the torque of the output shaft of the transmission which occurs during an initial stage of a gear shaft, resulting shift shock, can be decreased by effectively utilizing the rotation inertia of an engine by temporarily increasing the engaging force of the clutch during the initial period.