Abstract: An automatic transmission of the present invention is provided with: a plurality of rotating shafts; a plurality of gears; a plurality of synchronizing mechanisms including an output-side synchronizing mechanism; a lubricating oil storage part that stores a lubricating oil which is drawn upward by rotation of the gears; a shift position detection unit that detects which of a plurality of shift positions, including a neutral position, has been selected; and a control unit which, if the neutral position has been detected by the shift position detection unit, causes a synchronizing mechanism other than the output-side synchronizing mechanism to operate, and brings a clutch into a connected state after coupling a rotating shaft other than an output shaft and a gear other than an output-side gear.

Abstract: An automatic transmission is provided with a frictional engagement member that is operated by hydraulic pressure for shifting the automatic transmission, and includes an air vent opening. An automatic transmission controller includes a pressure regulator and a control section. The pressure regulator regulates the hydraulic pressure in response to a hydraulic pressure control signal. The control section performs an air vent operation of venting air from the frictional engagement member through the air vent opening. The air vent operation includes: a preliminary operation of setting the hydraulic pressure control signal to a preliminary pulse indicative of a preliminary value of pressure, wherein the preliminary value is lower than a normal value of pressure; and a normal operation of setting the hydraulic pressure control signal to a normal pulse indicative of the normal value, wherein the normal pulse follows the preliminary pulse.

Abstract: A hydraulic oil supply circuit of a work vehicle is configured to supply hydraulic oil to a transmission. A hydraulic oil warming circuit is configured to warm up the hydraulic oil. A control unit is configured to control the transmission, the hydraulic oil supply circuit, and the hydraulic oil warming circuit. The transmission includes a hydraulic clutch and a clutch control valve. The clutch control valve is configured to control the pressure of the hydraulic oil supplied to the hydraulic clutch according to a command from the control unit. When the control unit determines that the temperature of the hydraulic oil is low, it is configured to output a warming up command for operation of a warming up function. The hydraulic oil warming circuit is configured to warm up the hydraulic oil by causing a pressure loss in a flow path for the hydraulic oil.

Abstract: A system and a method that control warm-up of clutch fluid in a hybrid electric vehicle. The hybrid electric vehicle includes a clutch that controls power delivery between an engine and a motor and an oil pump that is operated by the motor and generates hydraulic oil pressure operating the clutch. The method includes determining, by a controller, whether delivery of power from the engine and motor in a transmission is cut and detecting temperature of the fluid using an oil temperature detector. In addition, the motor is maintained by the controller at a predetermined target speed to operate the oil pump connected to the motor when the detected temperature of the fluid is equal to or less than a predetermined temperature, wherein the predetermined target speed is a motor speed at which sufficient pressure for flowing the fluid is generated in the oil pump operating with the motor.

Abstract: The present invention relates to a speed variation transmission device for a motor vehicle powertrain comprising an epicyclic gear train (26) with a sun gear (36) and a crown (50) connected to shaft (12) of thermal engine (10) of said vehicle, as well as a planet gear carrier (58) connected by a motion transmission track (102) to drive axle (16) of this vehicle. According to the invention, sun gear (36) and crown (50) are connected each to engine shaft (12) by a controlled coupling (28, 30) and to a fixed part (48a, 48b) of the vehicle powertrain by a one-way coupling (32, 34).

Abstract: An electric oil pump system and a control method thereof include an electrical oil pump that is derated or the derating of the electrical oil pump is released according to a coil temperature of the electrical oil pump, and a torque of a transmission is control according to whether or not the electrical oil pump is derated.

Abstract: Assembly of multiple individual fluid pressure control solenoid valves and an individual fluid temperature sensor so packaged relative to a respective one of the individual solenoid valves as to permit direct or indirect fluid temperature measurement at individual solenoid valves. The assembly can include a lead-frame support (e.g. a printed circuit board) having multiple individual fluid pressure control solenoid valves and an individual transmission oil temperature sensor disposed on the lead-frame support in an oil passage that communicates to an output flow port of a respective one of the individual solenoid valves to provide transmission oil temperature information to a transmission electronic control unit, wherein the transmission electronic control unit provides command signals to the individual solenoid valves in response to the individual transmission oil temperature input signals associated with an individual solenoid valve to achieve more accurate pressure control.

Abstract: An automatic transmission includes: a frictional engagement element arranged to be switched from an engagement state to a disengagement state at a switching from a running range to a neutral range, and including: frictional plates; a first piston arranged to push the frictional plates; a second piston arranged to push the frictional plates; a first hydraulic chamber arranged to receive a hydraulic fluid for pushing the first piston; and a second hydraulic chamber arranged to receive a hydraulic fluid for pushing the second piston; a first discharge speed switching section arranged to switch only a discharge speed of the hydraulic fluid of the first hydraulic chamber; and a control unit configured to increase the discharge speed of the hydraulic fluid of the first hydraulic chamber during a predetermined time period by the first discharge speed switching section at the switching from the running range to the neutral range.

Abstract: A control device for an automatic transmission 10 having shift control means 88 operative to select a manual shift mode is provided for preventing acceleration response from deteriorating in the automatic transmission 10. The control device includes automatic up-range control means 90 for switching a range to a “D” range when high oil-temperature determining means determines presence of a high oil-temperature state, and high oil-temperature down-range permitting means 92 for permitting a down-range during a manual shift operation until a selected uppermost gear position GSELECT reaches a determining gear position GJUGE when the accelerator-on drive determining means 86 subsequently determines presence of an accelerator-on drive. Even when obtaining a drive force is attempted during an accelerator-on drive mode after switching the range, the down-range by the manual shift operation is permitted until the selected uppermost gear position GSELECT reaches the determining gear position GJUGE.

Abstract: A hydraulic control apparatus for an automatic transmission includes linear solenoid valves each configured to control a line pressure in accordance with an electromagnetic force of a solenoid. The linear solenoid valves each include a spool and are controlled under a normal hydraulic control mode or a current consumption decrease mode. The spool is actuated in accordance with the electromagnetic force. An output fluid pressure is controlled to be a maximum output fluid pressure from a minimum output fluid pressure with the spool at a balanced position under the normal hydraulic control mode. A current consumption for generating the electromagnetic force is decreased to make the fluid pressure equal to or lower than the minimum output fluid pressure under the normal hydraulic control mode and to hold the fluid pressure within a range corresponding to the balanced position under the current consumption decrease mode.

Abstract: A drive control device of an automatic transmission of a vehicle. The transmission having a main oil pump driven by an internal combustion engine, an electrically driven auxiliary oil pump and a hydraulic control device; a device for determining the required volumetric flow rate needed to determine the oil/hydraulic target volumetric flow rate during current operating conditions, based on the transmission oil temperature; a device for determining the volumetric flow rate to determine the actual volumetric flow rate that can be delivered during the current operating conditions by the main and/or auxiliary oil pump, and a device for controlling the target volumetric flow rate to reduce the target volumetric flow rate to at least the currently deliverable actual volumetric flow rate, if the currently deliverable actual volumetric flow rate is below the current target volumetric flow rate.

Abstract: A method for controlling trapped air in a clutch of an automatic clutch-to-clutch transmission includes, calculating a pulse on time based on a clutch volume and adaptive convergence. A pulse off time is calculated based on a temperature of transmission fluid. A pulse number is calculated based on the temperature of transmission fluid. A maximum pressure is commanded to the clutch based on the pulse on time and a minimum pressure is then commanded to the clutch based on the pulse off time. A pulse counter is incremented when the pulse off time expires. The steps of commanding maximum pressure, then commanding minimum pressure, and incrementing the pulse counter are repeated until the pulse counter equals a desired pulse number.

Abstract: A method for heating a transmission is provided. The transmission has at least one solenoid valve that hydraulically actuates a valve. The method includes the steps of measuring a transmission temperature, determining whether the transmission temperature is greater than or equal to a desired operating temperature, determining a currently selected gear ratio of the transmission, and overdriving at least one solenoid valve if the transmission has not achieved the desired operating temperature and if overdriving the solenoid valve will not disrupt the operation of the transmission for the currently selected gear ratio.

Abstract: A flow management valve is operative to enable a multi-range electro-mechanical transmission in first and second ranges. Fluid pressure in a hydraulic circuit is monitored to detect a fault in the flow management valve.

Abstract: In system and method of controlling an automatic transmission that includes a lowest gear-stage friction element and has a lowest gear stage having a largest gear ratio and a gear stage other than the lowest gear stage, the lowest gear stage being established through engagement of the lowest gear-stage friction element, the gear stage other than the lowest gear stage being established while the lowest gear-stage friction element is kept in disengagement, a temperature of working oil in the automatic transmission is sensed, and use of the lowest gear stage is inhibited and use of the gear stage other than the lowest gear stage is allowed when the sensed temperature of the working oil is lower than a first predetermined temperature as a predetermined extremely low temperature at which an engagement failure of the lowest gear-stage friction element is caused.

Abstract: An automatic transmissions control system varies times to start a shift to securing a good response in engagement pressure for an engagement-side frictional element as well as suppressing occurrence of hydraulic pressure vibrations at low temperatures.

Abstract: An automatic transmission includes: a frictional engagement element arranged to be switched from an engagement state to a disengagement state at a switching from a running range to a neutral range, and including: frictional plates; a first piston arranged to push the frictional plates; a second piston arranged to push the frictional plates; a first hydraulic chamber arranged to receive a hydraulic fluid for pushing the first piston; and a second hydraulic chamber arranged to receive a hydraulic fluid for pushing the second piston; a first discharge speed switching section arranged to switch only a discharge speed of the hydraulic fluid of the first hydraulic chamber; and a control unit configured to increase the discharge speed of the hydraulic fluid of the first hydraulic chamber during a predetermined time period by the first discharge speed switching section at the switching from the running range to the neutral range.

Abstract: In relation to an automatic transmission which has a plurality of friction engagement devices that are engaged when supplied with oil pressure and which establishes a plurality of speed change steps in accordance with engaged and released states of the friction engagement devices, a control device of a vehicular automatic transmission that switches between the speed change steps in accordance with a predetermined shift rule includes a controller which changes the shift rule to an air discharge-purpose shift rule that is set so as to provide a higher probability of switching to a speed change step that involves engagement of a predetermined friction engagement device of the friction engagement devices than the shift rule in order to discharge air that has intruded in a hydraulic circuit of the predetermined friction engagement device, and which causes switching between the speed change steps in accordance with the air discharge-purpose shift rule.

Abstract: There is provided a control system for electro-mechanical transmission that is selectively operative in a plurality of fixed gear modes and continuously variable modes comprising first and second electrical machines and four hydraulically-actuated clutches in fluid communication with a hydraulic circuit comprising first, second and third pressure control devices and first and second flow management valves. The control system is operative to selectively actuate the pressure control devices and the flow management valves based upon a demand for torque, presence of a fault, and temperatures of the electric machines.

Abstract: A shift control method and apparatus of an automatic transmission for controlling a shift from one speed, achieved by engagement of a first and a second frictional element, to another speed, achieved by engagement of a third and a fourth frictional element. The method includes detecting a rotation speed of a turbine, detecting a rotation speed of at least one operating member of at least one planetary gear set of the automatic transmission, and controlling the shift according to the rotation speeds of the turbine and the operating member. The control includes overlapping a first shift, fromn the one speed to an additional speed, with a second shift, from the additional speed to the other speed. The additional speed has a gear ratio that is near a gear ratio of the one speed.

Abstract: There is provided a control system for electro-mechanical transmission that is selectively operative in a plurality of fixed gear modes and continuously variable modes comprising first and second electrical machines and four hydraulically-actuated clutches in fluid communication with a hydraulic circuit comprising first, second and third pressure control devices and first and second flow management valves. The control system is operative to selectively actuate the pressure control devices and the flow management valves based upon a demand for torque, presence of a fault, and temperatures of the electric machines.

Abstract: An automatic transmission controller has an electronic control circuit, an electromagnetic valve, and a pressure control valve. The electronic control circuit generates a control current. The electromagnetic valve regulates a command pressure in accordance with the control current. The pressure control valve has a spool and is formed with a spool hole. The spool reciprocates in the spool hole in accordance with the command pressure to regulate a pressure supplied to a friction element of an automatic transmission. In a standby state, when the friction element is in a disengaged state, the electronic control circuit generates an oscillating current as the control current so that the electromagnetic valve generates a standby command pressure that makes the spool reciprocate in a range in which no pressure is supplied to the friction element.

Abstract: A torque control selection portion selects one of a first torque control portion and a second torque control portion as a control portion that controls a torque output from an automatic transmission, based on a vehicle condition. The first torque control portion controls the output torque by controlling an engagement pressure for a first clutch or a second clutch. The second torque control portion controls the output torque by controlling a reaction torque borne by a first motor when transmission of power is permitted in a shift mechanism.

Abstract: The state of a fluid coupling in a motor vehicle powertrain is selectively controlled during neutral idle operation of the engine for increasing the engine temperature to a desired level. The fluid coupling includes an input member connected to the engine and an output member connected to the transmission, and the output member is selectively grounded under specified enable conditions to impose an engine load for raising the engine operating temperature. The output member is released to resume normal operation of the powertrain when the enable conditions are no longer met or an estimate of the fluid temperature in the coupling reaches or exceeds a predefined temperature.

Abstract: A friction apply device, from among each pair of friction apply devices that are applied to achieve a speed from first speed to fourth speed, that is to be placed in a slipping state is selected based on a heat load when a neutral control is executed. As a result, it is possible to continue to execute the neutral control without the durability of the friction apply device being impaired by the heat load, for example, thereby increasing a fuel efficiency effect and the like achieved by the neutral control.

Abstract: A drive axle assembly for use in an all-wheel drive vehicle having a first hydraulic coupling operable to automatically transfer drive torque to a secondary driveline in response to slip of the primary driveline and a second hydraulic coupling operable to bias torque and limit slip between the wheels of the secondary driveline. The first hydraulic coupling is electronically-controlled.

Abstract: A drive axle assembly for use in an all-wheel drive vehicle having a first hydraulic coupling operable to automatically transfer drive torque to a secondary driveline in response to slip of the primary driveline and a second hydraulic coupling operable to bias torque and limit slip between the wheels of the secondary driveline.

Abstract: A hydraulic control system for an automatic transmission includes a lubrication passage for feeding lubricating oil to a wet clutch and lubrication points of the transmission, first and second passages with a large-diameter orifice and a small-diameter orifice, respectively, arranged upstream of the lubrication passage, a switching valve for switching fluid communication between the lubrication passage and the first and second passages, a solenoid for controlling the switching valve, and an ECU for controlling the solenoid.

Abstract: A pressure regulating valve which is comprised of a valve body being comprised of a cylinder, a spool slidably disposed in the cylinder with a clearance, the spool and the cylinder defining a pressure chamber and a space portion, and an urging member which urges the spool in a direction opposite to a direction of a force applied to the spool by fluid pressure in the pressure chamber. A supply passage fluidly communicates the cylinder and a fluid pressure supply source, and a drain passage fluidly communicates the cylinder and a sump. A through-passage formed in the spool fluidly communicates the pressure chamber and the space portion. An orifice disposed between the space portion and a sump limits a flow rate of fluid drained from the space portion to the sump. The spool is made of material having a lower thermal expansion coefficient than material of the valve body.

Abstract: Apparatus for controlling a vehicle automatic transmission having a hydraulically operated frictional coupling device operable to effect a shifting action of the automatic transmission, a switching valve operable according to a shifting command to effect the shifting action, and a pressure regulating valve operable to control a pressure of a working fluid to be supplied to the frictional coupling device through the switching valve to effect the shifting action, the apparatus including (a) a fluid temperature detector operable to detect a temperature of the working fluid, and (b) a delaying device operable to delay a moment of initiation of an operation of the pressure regulating valve to control the pressure of the working fluid to be supplied to the frictional coupling device for effecting the shifting action, such that the moment of initiation is delayed depending upon the detected working fluid temperature, to reduce a shifting shock of the automatic transmission.

Abstract: A control apparatus controls the temperature of hydraulic fluid in a power-transmission system that has a hydrodynamic power-transmission system designed to transmit power between one rotational member and the another rotational member and that has a transmission coupled to the another rotational member in such a manner that power can be transmitted. The temperature of the hydraulic fluid can be controlled by controlling a subsystem associated with the power-transmission system while a vehicle is coasting.

Abstract: A drive axle assembly for use in an all-wheel drive vehicle having a first hydraulic coupling operable to automatically transfer drive torque to a secondary driveline in response to slip of the primary driveline and a second hydraulic coupling operable to bias torque and limit slip between the wheels of the secondary driveline.

Abstract: A method of shortening response time during a gear shifting operation process is applicable to a semi-automatic, electronically controlled transmission of motor vehicles, in particular utility vehicles, takes into account a driver's reaction time to reduce delay in clutch re-engagement. To initiate a gear-shifting operation in such a transmission, the driver actuates a shifting command emitter and at the same time disengages a clutch typically by depressing a clutch pedal. In response thereto, a newly selected gear is engaged in the transmission by an electronic system using outside force assistance, for example compressed fluid. The driver is informed via an acknowledgment device when the clutch can be properly engaged once more.

Abstract: A hydraulic pressure control apparatus for controlling an automatic transmission of an automotive vehicle, with a pressurized working fluid delivered from a hydraulic pump driven by an electric motor, wherein a pump control device is operated upon starting of the electric motor to start the hydraulic pump, for controlling the electric motor, such that a rate of increase of the operating speed of the hydraulic pump decreases with a decrease in the temperature of the working fluid detected by a temperature detector.

Abstract: Apparatus for controlling a vehicle automatic transmission having a hydraulically operated frictional coupling device operable to effect a shifting action of the automatic transmission, a switching valve operable according to a shifting command to effect the shifting action, and a pressure regulating valve operable to control a pressure of a working fluid to be supplied to the frictional coupling device through the switching valve to effect the shifting action, the apparatus including (a) a fluid temperature detector operable to detect a temperature of the working fluid, and (b) a delaying device operable to delay a moment of initiation of an operation of the pressure regulating valve to control the pressure of the working fluid to be supplied to the frictional coupling device for effecting the shifting action, such that the moment of initiation is delayed depending upon the detected working fluid temperature, to reduce a shifting shock of the automatic transmission.

Abstract: A hydraulic control device for an automatic transmission capable of preventing engine racing and tie-up by controlling disengagement side oil pressure in accordance with an input torque and an oil temperature. Gear-change execution controller U4 controls drain timings T1 and T3 and a drain gradient &dgr;P of the disengagement side oil pressure acting on the frictional engagement elements of the disengagement side according to the magnitude of the input torque and elevation of the oil temperature in torque phase control wherein both the engagement side oil pressure and the disengagement side oil pressure are controlled.

Abstract: A hydraulic control system controls a hydraulic pressure as a standby pressure in a period from an engagement start point at which an engagement instruction for engaging a friction element is started to an abutment start point at which an abutment between an input element and an output element is started. The hydraulic pressure supplied to at least one friction element is so increased as to switch the friction element from a disengagement state to an engagement state, thus transmitting a revolution of the input element of the friction element to the output element of the friction element. The hydraulic control system includes: a speed sensor for sensing a speed of the friction element; and a standby pressure increase section for increasing the standby pressure in accordance with the speed of the friction element sensed with the speed sensor.

Abstract: A flow control valve for regulating the flow across an orifice to eliminate the effects of viscosity changes throughout a range of temperatures for the hydraulic fluid. The valve includes a base with an orifice and a slide valve element that registers with the orifice and that is movable by a double, helix-wound, bimetallic spring. The bimetallic spring extends linearly in the direction of motion of the slide valve element so that its effective length will change a predictable amount for a given temperature change, thereby progressively changing the size of the orifice as the spring moves the slide valve element to which it is connected.

Abstract: An improvement is made to a torque splitting device employing hydraulic clutches so as to avoid any discontinuity in the control even when the properties of the actuating oil such as the pressure and temperature thereof deviate from standard values. For instance, when the oil temperature is low, the target value of the oil pressure for each of the clutches is modified to a lower value. Thus, it becomes possible to make less pronounced any delay in the response of the torque splitting device which may arise due to the sluggishness of the oil as it flows out of the clutch cylinder. The oil pump is typically actuated by a member rotating at a speed proportional to the vehicle speed, and the pressure output of the pump may be inadequate in a low speed range. In such a case, the target value is again reduced so as to reduce any abrupt change in the property of the torque splitting device when the vehicle is accelerated from a low speed.

Abstract: A control system for an automatic transmission, in which a first frictional engagement element and a second frictional engagement element are released according to a shift from a running range to a non-running range. The shift from the running range to the non-running range is detected, and the reduction in the oil pressure of the second frictional engagement element is controlled on the basis of the reduction in the oil pressure of the first frictional engagement element when the shift from the running range to the non-running range is detected.

Abstract: A fluid pressure control apparatus for use with an automatic transmission having a hydraulic circuit connected to supply a fluid pressure so as to operate selected ones of friction elements in the engaged position and release the fluid pressure so as to operate selected ones of the friction elements in the disengaged positions. The control apparatus controls the fluid pressure to the friction elements according to a shift from a current gear position to a target gear position. The fluid pressure is applied temporarily to disengaged ones of the friction elements so as to exhaust air from the hydraulic circuit.

Abstract: An oil temperature responsive hydraulic control system for an automatic transmission includes a hydraulic servo for applying/releasing a frictional engagement element; a pressure regulator valve for regulating oil pressure fed to the hydraulic servo; and a signal pressure oil passage for applying a pressure regulating signal pressure to the pressure regulator valve. A control valve is arranged in the signal pressure oil passage for changing the effective diameter of the signal pressure oil passage responsive to change in oil temperature.

Abstract: A transmission warm-up control strategy is provided for an automatic transmission used in a machine that is started or operated in cold conditions. When the operating value of the oil in the transmission is below a predetermined level, as sensed by a temperature sensor or a viscosity sensor, a controller turns on an indicator lamp, de-energizes all of the solenoid to the solenoid actuated valves, and holds for a predetermined period of time. The respective solenoids are incrementally energized and held for a second period of time while continuously monitoring the operating condition of the oil in the transmission. Once the operating condition of the oil is above the predetermined operating value, the indicator lamp is turned off and the system is returned to normal operating conditions. If the shift lever is moved from the park position during warm-up, all solenoids are de-energized and the indicator lamp is set to flash.

Abstract: A shift control arrangement for an automotive automatic transmission includes a control unit active to change the state of a solenoid disposed in a hydraulic circuit of an automatic transmission during shifting so as to appropriately effect engagement and/or release of a frictional element of the automatic transmission. The control unit is further provided with a fluid temperature compensating portion so as to delay or advance a time of actuation of the solenoid, according to a detected gear ratio, to compensate for changes in fluid viscosity due to temperature, such that optimal shift characteristics for the frictional element are always maintained.