Abstract: In general, an oil pump driving control device for a hybrid vehicle is described. A hybrid vehicle includes a drive-train configured and arranged to transmit power in the order of an engine, a first clutch, a motor generator, a second clutch and a drive wheel, and an oil pump operably configured and arranged at a location between the first clutch and the second clutch such that the oil pump is mechanically driven by at least one of the engine and the motor generator. The invention provides an oil pump driving control device that supplies the necessary oil pressure for an automatic transmission with only a single mechanical oil pump. For example, even when it is not possible to maintain tightening of the second clutch, oil pressure may be supplied by rotating the oil pump using the motor generator. In this way, the oil pressure may be supplied with a single oil pump.

Abstract: A hybrid vehicle control system is configured to improve fuel economy by optimizing a torque transfer capacity of a clutch transmitting drive power from both an engine and a motor/generator while the motor torque provides at least part of the drive force. In particular, the system selectively controls a pair of clutches to switch between an electric drive mode and a hybrid drive mode. The torque transfer capacity of the clutch transmitting drive power from both the engine and the motor/generator to a drive wheel includes a motor/generator torque component and an engine torque component. The motor/generator torque component is determined based on a motor/generator torque and a torque transfer capacity margin allowance for the motor/generator torque. The engine torque component is determined based on an engine torque and a torque transfer capacity margin allowance for the engine torque when the drive wheel is driven at least by the motor/generator.

Abstract: A hybrid vehicle control system is configured to use automatic braking to compensate for an excess or deficiency of a braking force available from the power train of a hybrid vehicle that occurs when the hybrid vehicle switches from an electric drive (EV) mode to a hybrid drive (HEV) mode when the accelerator pedal depressing amount is detected as being substantially zero. In particular, hybrid vehicle control system determines whether a power train braking force from the power train is sufficient to achieve a target braking force. If the power train braking force is sufficient to achieve the target braking force when an accelerator pedal depressing amount is detected as being substantially zero, then a wheel brake is activated to apply a wheel braking force against a wheel of the vehicle to maintain the target braking force.

Abstract: A hybrid vehicle control system is configured to improve fuel economy by optimizing a torque transfer capacity of a clutch transmitting drive power from both an engine and a motor/generator while the motor torque provides at least part of the drive force. In particular, the system selectively controls a pair of clutches to switch between an electric drive mode and a hybrid drive mode. The torque transfer capacity of the clutch transmitting drive power from both the engine and the motor/generator to a drive wheel includes a motor/generator torque component and an engine torque component. The motor/generator torque component is determined based on a motor/generator torque and a torque transfer capacity margin allowance for the motor/generator torque. The engine torque component is determined based on an engine torque and a torque transfer capacity margin allowance for the engine torque when the drive wheel is driven at least by the motor/generator.

Abstract: An engine of a hybrid vehicle is lift started by reducing a rotational speed of a motor/generator of the hybrid vehicle by adjusting a gearshift ratio of a transmission coupled to the motor/generator, and engaging a clutch to couple the engine, while in a stopped state, to the rotating motor/generator for imparting the rotation to the engine.

Abstract: In general, an oil pump driving control device for a hybrid vehicle is described. A hybrid vehicle includes a drive-train configured and arranged to transmit power in the order of an engine, a first clutch, a motor generator, a second clutch and a drive wheel, and an oil pump operably configured and arranged at a location between the first clutch and the second clutch such that the oil pump is mechanically driven by at least one of the engine and the motor generator. The invention provides an oil pump driving control device that supplies the necessary oil pressure for an automatic transmission with only a single mechanical oil pump. For example, even when it is not possible to maintain tightening of the second clutch, oil pressure may be supplied by rotating the oil pump using the motor generator. In this way, the oil pressure may be supplied with a single oil pump.

Abstract: There is disclosed a motor vehicle having a set of front wheels, a set of rear wheels, an engine, and a transmission driven by the engine and having a transmission output shaft. The motor vehicle further has a transfer including a variable torque trasmitting (VTT) clutch for varying a distribution of torque between the set of front wheels and the set of rear wheels depending upon degree of engagement thereof. A clutch activating pressure is generated and transmitted to the VTT clutch under the control of a mode selector valve.

Abstract: A lockup control system for automatic transmissions is constructed to prohibit lockup of a torque converter when detecting inertia cruising of a motor vehicle even if transition of the cruising state of the motor vehicle occurs from a converter area to a lockup area.

Abstract: A lock-up controller of a lock-up control system reads-in a vehicle speed V, a throttle opening degree TVO, an engine speed Ne, and a turbine speed Kt from sensors and outputs a fuel-out command and a fuel-supply restart command to an engine controller, to operate a lock-up clutch in a torque converter of an automatic transmission for an automotive vehicle in an accelerator-off (coasting) state of the vehicle. The lock-up control system makes it possible to realize locking-up of the torque converter providing an improved fuel consumption ratio of the engine and a large braking force from the engine, even when a vehicle speed increases due to running down a downward slope while the accelerator-off state continues, or when an up-shifting speed change occurs due to the accelerator-off state.

Abstract: An automatic transmission is provided with at least one friction element and a piston. The engagement of the friction element is proceeded in a manner that operating pressure is applied to an apply chamber to stroke the piston. The disengagement of the friction element is proceeded in a manner that operating pressure is applied to a cancel chamber to stroke the piston. The cancel chamber is disposed opposite to the apply chamber with respect to the piston and formed such that an outer diameter of a pressure receiving surface of said cancel chamber is generally the same as that of said apply chamber. Therefore, piston pushing force due to centrifugal force in the apply chamber is balanced with a piston reversely pushing force due to the centrifugal force in the cancel chamber. This prevents the friction element from being dragged during friction element disengaged condition.

Abstract: A hydraulic pressure supply system for a variable torque transfer of a four-wheel drive vehicle in which a driving-torque distribution ratio between front and rear road wheels is varied by adjusting a clutch pressure applied to a variable torque clutch assembled in said transfer, comprises an oil pressure source supplying a pressurized working fluid into a hydraulic line, at least one pressure regulating valve fluidly connected to the line for decreasingly regulating the pressurized working fluid at a predetermined clutch pressure, and a directional control valve fluidly connected to the pressure regulating valve for directing the clutch pressure to a transfer clutch. An electromagnetic solenoid valve is provided for controlling the pressure regulating valve and the directional control valve for selectively supplying one of a stand-by pressure and a clutch engaging pressure to the transfer clutch.

Abstract: An improved lockup control system for a lockup-type torque converter for automotive vehicle performs a coasting lockup control of a lockup clutch with minimized response delay of lockup releasing control and suppressed lockup releasing shock upon acceleration of the vehicle. The control system includes a controller that is operative when the driving condition of a vehicle as represented by the throttle valve opening and the vehicle speed is judged to belong to a lockup region. The controller reduces the differential pressure across the lockup clutch to a lower limit value within a range in which the clutch can be prevented from slips. Thus, when the vehicle is reaccelerated and the driving condition shifts out of the lockup region, the reduction amount of the differential pressure is minimized to mitigate the response delay in the lockup releasing control.

Abstract: A control device of an automatic transmission capable of controlling the operation so as to suit the gearshift operation to a driver's pedalling operation for acceleration and deceleration. The control device selects a gearshift pattern corresponding to a result obtained by comparing a displacement per unit time of an accelerator pedal with a predetermined displacement per unit time of the accelerator pedal. Further, the device includes a microcomputer to monitor the driver's pedalling operation for acceleration and deceleration when the gearshift is carried out and to compensate the predetermined displacement per unit time of the accelerator pedal in such a manner that the driver's unnatural pedalling operation would not be required.

Abstract: An automatic transmission is provided with at least one friction element and a piston. The engagement of the friction element is proceeded in a manner that operating pressure is applied to an apply chamber to stroke the piston. The disengagement of the friction element is proceeded in a manner that operating pressure is applied to a cancel chamber to stroke the piston. The cancel chamber is disposed opposite to the apply chamber with respect to the piston and formed such that an outer diameter of a pressure receiving surface of said cancel chamber is generally the same as that of said apply chamber. Therefore, piston pushing force due to centrifugal force in the apply chamber is balanced with a piston reversely pushing force due to the centrifugal force in the cancel chamber. This prevents the friction element from being dragged during friction element disengaged condition.

Abstract: A clutch of an automatic transmission having a clutch drum having a fluid chamber defined therein clutch hub coaxially disposed within the clutch drum; a clutch plate pack operatively interposed between the clutch drum and the clutch hub; and a piston slidably disposed in the fluid chamber in such a manner that a movement of the piston in a given direction due to feeding of operating fluid into the fluid chamber presses the clutch plate pack. In the invention, there is provided in the clutch a fine passage which connects the fluid chamber to an open air. The fine passage is exposed to a radially inner portion of the fluid chamber, so that under rotation of the clutch drum, any remaining air is forced to move toward the fine passage by the operating fluid in the fluid chamber. The fine passage is sized to permit passing of air therethrough while blocking passing of the operating fluid.

Abstract: An automatic transmission includes first and second planetary gear sets, and a third planetary gear set which is closer to an output end of the transmission, and which is smaller in diameter than the first and second gear sets. One brake is disposed around the first and second planetary gear sets, and another brake has a pack of brake plates surrounding the smaller third planetary gear set. A transmission case is therefore made gradually smaller toward the output end. This planetary gear system makes it possible to arrange the brakes very compactly, and the tapered transmission case improves the rigidity of the automatic transmission.

Abstract: A structure of an automatic transmission includes first and second clutches which are arranged radially so that one is surrounded by the other. This arrangement can reduce the size of the automatic transmission. For example, the first clutch has a first clutch drum splined to an input shaft of the transmission, a first clutch hub, and a first clutch pack between the first clutch drum and hub. The second clutch has a second clutch drum received in, and splined to, the first clutch drum, a second clutch hub, and a second clutch pack therebetween. The second clutch pack is surrounded by the first clutch pack. The second clutch further includes a piston which encloses the first clutch drum and which has a pushing portion on one side of the second clutch pack and a pressure receiving portion on the opposite side.

Abstract: A lubricating system which is for an automatic transmission having planetary gear sets and producing various speeds by selectively engaging friction elements. The lubricating system is provided with a first lubricating circuit which usually supplies lubricant to planetary gear sets, bearings and the like, and a second lubricating circuit which supplies lubricant to friction elements during a shift.

Abstract: An automatic transmission includes a planetary gear system which are coaxially mounted on an intermediate shaft having a first end supported by an input shaft and a second end supported by an output shaft. For example, the planetary gear system includes three planetary gear sets which are all mounted on the intermediate shaft, and an engaging device group includes a combination of first and second clutches and a first brake which are all placed around the input shaft, and a combination of second and third brakes which are placed around the planetary gear sets. The three planetary gear sets are tightly arranged, leaving little or no intervening spaces, between both ends of the intermediate shaft. No clutches and brakes are interposed among the planetary gear sets. Therefore, it is possible to decrease the length of the intermediate shaft, and to reduce gear noises by improving the flexural rigidity of the intermediate shaft.

Abstract: An accumulator backup pressure which is electronically generated by a line pressure solenoid is applied to an overrunning clutch reduction valve. Thus, a working hydraulic pressure generated by the overrunning clutch reduction valve is variable with a vehicle speed and an engine brake running range selected by a driver. As a result, shockless downshift to engine braking is accomplished.