Abstract: A vehicle includes a power source, a transmission coupled to the power source, and a control unit. The transmission includes a torque converter and a hydraulic switching mechanism. A processor of the control unit is configured to execute in accordance with an instruction stored in a storage medium: obtaining RPM of a turbine shaft of the torque converter based on a unit time when the transmission is switched from neutral to forward driving or to reverse driving; determining whether the RPM is decreased by an amount greater than a predetermined amount of decrease based on the unit time; and reducing, if the RPM is decreased by an amount greater than the predetermined amount of decrease based on the unit time, pressure of oil to be supplied to an oil chamber of the hydraulic switching mechanism when the transmission switches to the same mode as the previously switched mode next time.

Abstract: A vehicle drive device including an engagement pressure flow channel, a lubrication flow channel, a first pump having a discharge port connected to the engagement pressure flow channel, a second pump, and a flow channel control valve. The flow channel control valve selectively switches flow channels between a first state in which an outflow destination of oil discharged from the second pump is the engagement pressure flow channel and a second state in which the outflow destination is the lubrication flow channel. When a failure in which the flow channel control valve is fixed in the second state has occurred, a control device for a vehicle control device performs fail-safe control in which a rotational speed of at least one of an internal combustion engine and a rotating electrical machine is increased to supply oil to the engagement pressure flow channel by the first pump.

Abstract: In a hybrid flight vehicle, having multiple rotors attached to a frame, a gas turbine engine to drive the rotors; a generator connected to the gas engine to generate electric power, a battery store the electrical power generated by the generator. multiple first electric motors connected to the rotors to drive the same by the electric power supplied from the battery, a second electric motor connected to the gas turbine engine to motor the engine by the electric power supplied from the battery and a control unit to control flight, wherein the control unit stops supply of the fuel to the engine when a detected residual of the battery is equal to or greater than a predetermined value, and supplies electric power to the second electric motor to motor the engine when a detected temperature of the engine is equal to or higher than a predetermined temperature.

Abstract: A method is disclosed for operating a multi-gear vehicle transmission in a motor vehicle during a coasting phase. The coasting phase includes an overrun phase with a driving gear engaged and a freewheeling phase with the neutral gear engaged. It is determined whether the motor vehicle is in the overrun phase of the coasting phase, whether a condition for a transition to the freewheeling phase of the coasting phase is fulfilled, and whether a transmission condition with elevated drag losses exists. If the motor vehicle is in the overrun phase of the coasting phase, if the condition for transition to the freewheeling phase is fulfilled, and if a transmission condition with elevated drag losses exists, then at least one further shifting element (D, E) is closed in addition to the shifting elements (A, B, C) of the driving gear, which are closed during the overrun phase of the motor vehicle.

Abstract: Systems and methods for operating a driveline disconnect clutch of a hybrid vehicle are presented. In one example, a time duration of a boost phase of a driveline disconnect clutch closing sequence is adjusted in response to one or more error values. The error values may include pressure error, integrated pressure error, and electric machine speed error.

Abstract: Disclosed are an apparatus and method for controlling an oil pump for a vehicle which may control the speed of the oil pump. The apparatus includes a controller configured to control the speed of the oil pump based on the temperature information of a motor and oil and the speed and torque information of the motor, and, when the vehicle is being driven, the controller confirms whether or not a motor or oil temperature is higher than or equal to a first set temperature, controls the speed of the oil pump to a maximum speed value when the motor or oil temperature is higher than or equal to the first set temperature, and calculates a control speed value and controls the speed of the oil pump to the calculated control speed value when the motor or oil temperature is lower than the first set temperature.

Abstract: A fluid assembly in a hydraulic circuit, comprising one or more reservoirs configured to store fluid. The fluid assembly also includes a pump configured to transport the fluid in the hydraulic circuit and actuate a load from a transmission of a motor vehicle, a pressure accumulator configured to collect pressure built up by the pump and actuate the load, and a valve system configured to allow fluid communication of the load with the pump.

Abstract: A pressure regulating passage includes a pressure regulating valve and a check valve. The pressure regulating valve regulates a hydraulic pressure supplied to a friction engagement element to be a predetermined pressure lower than an engagement pressure. The check valve prevents reverse flow of hydraulic oil supplied to the friction engagement element. An operative position of a manual valve is switched so as to switched between a passage that supplies hydraulic pressure to the hydraulic pressure supply passage while bypassing the pressure regulating passage and a passage that supplies hydraulic pressure to the hydraulic pressure supply passage through the pressure regulating passage. Accordingly, when an automatic transmission is in a D range and a vehicle is stopped, regardless of a line pressure, an N control process is performed to disengage the friction engagement element.

Abstract: An oil pump system and method of a hybrid vehicle stably supplies an operating hydraulic pressure to an automatic transmission using only an electric oil pump. The oil pump system of the hybrid vehicle, which supplies an operating hydraulic pressure to an automatic transmission of the hybrid vehicle, includes: an automatic transmission control unit controlling operation of the automatic transmission; an electric oil pump pumping oil to generate an operating hydraulic pressure which is to be supplied to the automatic transmission; and an oil pump control unit receiving information on a state of the automatic transmission from the automatic transmission control unit and controlling operation of the electric oil pump. The operating hydraulic pressure supplied to the automatic transmission may be generated solely through the electric oil pump which is electrically operated.

Abstract: A control apparatus for an automatic transmission including three frictional engagement elements is configured to set engagement pressures of first and second frictional engagement elements at the time when a predetermined shift speed is established such that a torque capacity of a third frictional engagement element becomes smaller than torque capacities of the first and second frictional engagement elements in the case where an engagement pressure is generated in the third frictional engagement element at the time when the predetermined shift speed is established.

Abstract: A transmission controller operates an electrical oil pump in a steady mode, in which an operating load of the electrical oil pump is set at a steady load, during an idle stop, but operates the electrical oil pump in a high-pressure mode, in which the operating load of the electrical oil pump is higher than the steady load, for a predetermined period when an engine stops rotating.

Abstract: A control device for a hybrid vehicle automatic transmission. A friction engagement element control unit includes a first play elimination control unit that sets a first pressure as the pressure for a first set time where the predetermined friction engagement element is engaged using a hydraulic pressure from the electric oil pump in a travel state in which only the rotary electric machine serves as a drive source. The first play elimination pressure is lower than a play elimination pressure for use in the case where the predetermined friction engagement element is engaged using a hydraulic pressure from the mechanical oil pump in a travel state in which the internal combustion engine serves as a drive source.

Abstract: A hydraulic pump system for an automatic transmission has the advantages of preventing excessive power loss and durability deterioration. The hydraulic pump system may include a first hydraulic pump that generates a first hydraulic pressure to supply a low pressure portion with the first hydraulic pump, a second hydraulic pump that receives the first hydraulic pressure to generate a second hydraulic pressure higher than the first hydraulic pressure and supplies a high pressure portion with the second hydraulic pressure, and a drive portion that rotates a drive shaft that integrally connects the first hydraulic pump with the second hydraulic pump.

Abstract: A hydraulic control system in a transmission includes a source of pressurized hydraulic fluid and a compensator valve in communication with the source of pressurized hydraulic fluid and a torque transmitting device. The compensator valve is operable to allow communication of the hydraulic fluid from the source of pressurized hydraulic fluid to the torque transmitting device to release the torque transmitting device. A regulation valve is in communication with the source of pressurized hydraulic fluid and the torque transmitting device. The regulation valve is moveable between a first position that prevents the hydraulic fluid from communicating with the torque transmitting device and a second position that allows the hydraulic fluid to communicate with the torque transmitting device to engage the torque transmitting device. An override feature is operable to prevent the compensator valve from communicating the hydraulic fluid to the torque transmitting device when the torque transmitting device is engaged.

Abstract: At pre-shift of a shift control, a line pressure control section determines a pressure raising amount ?PL of a line pressure PL on the basis of a pressure raising amount map stored in a memory, and controls a line pressure controlling linear solenoid valve so that the line pressure PL regulated by a regulator valve is raised by this pressure raising amount ?PL. For example, a control hydraulic pressure corresponding to the pressure raising amount ?PL is applied to the regulator valve from the line pressure controlling linear solenoid valve. Thus, hydraulic oil supplied from an oil pump is mostly discharged from an output port for the line pressure PL. Therefore, although there is a possibility that the line pressure PL regulated within a line pressure circuit somewhat varies when stroke of a hydraulic piston starts, a decrease of the line pressure PL is suppressed sufficiently compared with the case where the line pressure PL is not raised as a conventional manner.

Abstract: A hydraulic pressure control apparatus for an automatic transmission may include a first hydraulic pump connected with an oil tank to receive oil from the oil tank, having a first motor, and adapted to generate a low pressure through an operation of the first motor, a second hydraulic pump connected with the first hydraulic pump to receive the low pressure, having a second motor, and adapted to generate a high pressure through an operation of the second motor, a first regulating valve adapted to receive the low pressure from the first hydraulic pump and to regulate a first operating pressure to supply to the torque converter, and a second regulating valve adapted to receive the high pressure from the second hydraulic pump and to regulate a second operating pressure to supply to the powertrain.

Abstract: A power transmission device that includes a clutch that transmits power from a motor to an axle; a first pump that is driven by power from the motor to generate and output fluid pressure; a second pump that receives and is driven by a supply of electric power to generate and output fluid pressure; a line pressure generating valve that is operated by operation fluid input to an operation input port, and regulates fluid pressure output from the first pump to generate a line pressure for engaging the clutch; and a switching valve that switches between a first connection state and a second connection state.

Abstract: A hydraulic control system for a dual clutch transmission includes a plurality of solenoids and valves in fluid communication with a plurality of clutch actuators and with a plurality of synchronizer actuators. The clutch actuators are operable to actuate a plurality of torque transmitting devices and the synchronizer actuators are operable to actuate a plurality of synchronizer assemblies. Selective activation of combinations of the solenoids allows for a pressurized fluid to activate at least one of the clutch actuators and synchronizer actuators in order to shift the transmission into a desired gear ratio.

Abstract: A power transmission device that includes a clutch that transmits power from a motor to an axle; a first pump that is driven by power from the motor to generate and output fluid pressure; a second pump that receives and is driven by a supply of electric power to generate and output fluid pressure; a pressure regulating valve that regulates a pressure of operation fluid output from the first pump, and delivers at least a portion of operation fluid discharged in connection with the pressure regulation to a lubrication target for use as lubricant; and a switching valve that switches between a first connection state and a second connection state.

Abstract: A method to control a powertrain including a transmission, an engine, and an electric machine includes applying through a series of clutch fill events a series of incrementally changing command pressures in a pressure control solenoid controllably connected to a clutch within the transmission, monitoring a pressure switch fluidly connected to the pressure control solenoid and configured to indicate when the pressure switch is in a full feed state, determining changes in cycle times of the pressure switch corresponding to sequential applications of the series of incrementally changing command pressures, selecting a preferred command pressure to achieve a transient state in the clutch based upon the changes in pressure switch cycle times, and controlling the clutch based upon the preferred command pressure.

Abstract: A method of monitoring a hydraulic or pneumatic transmission control system, which comprises a pressure supply unit with a conduit directing a pressure medium under a supply pressure, and an actuating member for a clutch control element of a friction clutch. The actuating member has a pressure space which can be connected by a clutch control valve to the conduit, and in which the supply pressure is determined by a pressure sensor that can be connected to the conduit. The method includes the steps of determining the supply pressure by the pressure sensor, given that briefly opening the clutch control valve produces a pressure increase and/or a pressure gradient of the control pressure in the pressure space, and the currently existing supply pressure can be calculated from the control pressure, the pressure increase and/or the pressure gradient.

Abstract: A hydraulic control device with a plurality of gear-actuating cylinders for engaging and disengaging the gears of an automated multi-step transmission, with pressure-controlled gear-regulating valves for controlling the pressure in one pressure chamber of the cylinders, and with a multiplex arrangement of singly switchable pressure-controlled selector valves for assigning the regulating valves to one pressure chamber of the actuating cylinders. The device includes a common pilot valve, designed as a regulating valve, for actuating one of the regulating valves and at least one of the selector valves. The pilot valve features a first control pressure range that contains the switching pressure of the selector valve and a second control pressure range that contains the regulating range of the gear-regulating valve.

Abstract: In an abnormal-period automatic shift control apparatus of an automated manual transmission (AMT), a controller includes a first state detecting section configured to detect whether the AMT is in a first state where the AMT is thrown into a shift stage during an engine starting period, and a second state detecting section configured to detect whether the AMT is in a second state where a clutch failure that an automatic clutch, employed in the AMT for engine power transmission, remains engaged undesirably, occurs. Also provided is a neutral-range-period abnormality countermeasure section configured to inhibit a supply of working oil from an engine-drive oil pump, serving as a working medium for automatic-clutch engagement-and-disengagement control and automatic gear shifting, for preventing an automotive vehicle from beginning to move, while a selected operating range is a neutral range, under a condition where the first and second states occur simultaneously.

Abstract: A method for shifting a gear into a gear position in an automated shift transmission with several gears and an automated shift transmission adapted to perform said method are suggested. Via a shifting fork, a shifting sleeve can be shifted from a neutral position into respective gear positions and reaches on its way a pull-in position where the shifting sleeve is automatically forced in direction of the gear position. It is achieved that the pull-in position is safely reached by checking whether the shifting fork has reached a first threshold value, a second threshold value, and whether it has come to a standstill therebetween. Accordingly, an increased shifting force can be applied. Albeit allowing production tolerances in the transmission, the respective gear position is safely reached.

Abstract: A hydraulic or pneumatic control device for an automated shift transmission including actuating devices with actuating cylinders (15, 16) having pressure spaces (19a, 19b; 20a, 20b). The pressure spaces (19a, 19b; 20a, 20b) of the actuating cylinders (15, 16) can be connected by a respective control valve (22a, 22b; 32a, 32b) to a pressure line (26), which can be selectively connected to or cut off from a main pressure line (8) by a main shut-off valve (45a). At least one additional main shut-off valve (45b) is arranged in parallel with the first main shut-off valve (45a) between the main pressure line (8) and the pressure line (26) to improve the control characteristics and increase the operational reliability.

Abstract: A lubricating oil supply control device for delivering lubricating oil to the transmission of a vehicle is provided which overcomes disadvantages of the prior art by providing a simple and reliable configuration which does not require the addition of new sensors to an existing device. The lubricating oil supply control device includes, in part, an engine controller and a transmission controller, a lubricating oil supplying oil passage, a bypass oil passage, a relief valve or a control valve, a restrictor, and a lubricating oil supply controlling controller.

Abstract: A clutch engagement control system for a vehicle transmission. The system comprises an automatic transmission gearset and at least one hydraulic clutch coupled to the gearset. A hydraulic pressure controller is coupled to the clutch. A clutch engagement controller is coupled to the pressure controller, and an altitude sensor is coupled to the clutch engagement controller. The clutch engagement controller is configured to receive from the altitude sensor an altitude signal corresponding to the altitude of the vehicle. The clutch engagement controller adjusts a hydraulic pressure request of the pressure controller in accordance with the altitude signal, such that the clutch engages with at least one of a rate and pressure corresponding to the sensed altitude. A method employs the system.

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: The present invention provides a system for shifting or controlling a dual clutch transmission where the transmission may operate in at least a first mode of operation and a second mode of operation. The system includes a controller and a plurality of solenoids in fluid communication with a valve assembly. Selective activation of the solenoids by the controller engages the valve assembly to provide the first mode and the second mode of operation.

Abstract: An ECU executes a program that includes a step of determining whether an output shaft rotation speed NOUT is equal to or greater than a reference rotation speed at which determining regions with all of the gear speeds in a stepped automatic transmission do not overlap, a step of determining that there is an abnormality in the gear speed by dividing the turbine rotation speed NT by the output shaft rotation speed NOUT if the output shaft rotation speed NOUT is not equal to or greater than that reference rotation speed, and a step of determining that there is an abnormality in the gear speed by subtracting a value, which is obtained by multiplying the output shaft rotation speed NOUT by the gear ratio, from the turbine rotation speed NT if the output shaft rotation speed NOUT is equal to or greater than that reference rotation speed.

Abstract: In a vehicle powertrain that continually transmits power to a first set of vehicle wheels and selectively transmits power through a clutch to a second set of vehicle wheels, a method for controlling the clutch includes determining that brakes for slowing the vehicle wheels are applied and that an accelerator pedal of the vehicle is depressed less than a reference magnitude, determining that the rate of change of the average front wheel speed is greater than the rate of change of the average rear wheel speed, and setting the torque capacity of the clutch to a target magnitude.

Abstract: A gear shift controlling apparatus of an automatic transmission for a vehicle has a synchronization-time engagement pressure correcting device that, before synchronization of gear-shifting, makes an increase correction of an engagement pressure of the disengaged-side engaging element by a first prescribed amount, to cause an input shaft rotational speed immediately before synchronizing of the automatic transmission to approach a rotational speed calculated by multiplying an output shaft rotational speed by a gear ratio of a gear after gear-shifting the automatic transmission.

Abstract: A hydraulic control device with a plurality of gear-actuating cylinders for engaging and disengaging the gears of an automated multi-step transmission, with pressure-controlled gear-regulating valves for controlling the pressure in one pressure chamber of the cylinders, and with a multiplex arrangement of singly switchable pressure-controlled selector valves for assigning the regulating valves to one pressure chamber of the actuating cylinders. The device includes a common pilot valve, designed as a regulating valve, for actuating one of the regulating valves and at least one of the selector valves. The pilot valve features a first control pressure range that contains the switching pressure of the selector valve and a second control pressure range that contains the regulating range of the gear-regulating valve.

Abstract: In a fail-safe mechanism for an automatic transmission (3), when a predetermined gearshift (Rev) is positioned in the automatic transmission (3) during a non-failure state of the automatic transmission, a first valve unit (70) moves from a non-failure position toward a failure position as the oil pressure for positioning the predetermined gearshift (Rev) is caused to act on a fail-safe valve (50) as an extraneous matter-discharging oil pressure (PR).

Abstract: A hydraulic control device for an automatic transmission is provided. The hydraulic control device can sets up any gear from a plurality of gears by causing any one of a plurality of frictional engagement elements to selectively carry out an engagement operation. The hydraulic control device includes: a regulator valve that regulates base oil pressure of hydraulic oil supplied from an oil pressure source; a relief valve provided in a lubricating oil passage connected from the regulator valve; and a line pressure switching section that sets up line pressure to low pressure to reduce the amount of lubricating oil in a region in which engagement hydraulic oil pressure does not require high engagement hydraulic oil pressure depending upon an operation state of a vehicle, and sets up the line pressure to high pressure when a target value of the engagement hydraulic oil pressure exceeds predetermined pressure.

Abstract: A hydraulic control apparatus for an automatic transmission comprises a linear solenoid valve for outputting a control pressure, a primary regulator valve for regulating a line pressure in accordance with the control pressure, and a secondary regulator valve for regulating a secondary pressure in accordance with the control pressure, the secondary pressure being supplied to a lock-up clutch and a torque converter. A spool of the secondary regulator valve is formed to comprise a large diameter portion and a small diameter portion, thereby eliminating the need for components such as a sleeve, and the line pressure can be input into an oil chamber formed between the large diameter portion and small diameter portion.

Abstract: An apparatus and method for controlling line pressure of an automatic transmission. A driving information detection unit obtains information. A shift control unit determines if a power-on downshift is requested based on the information of the driving information detection unit, and controls the line pressure based on if the power-on downshift is requested. An actuator forms the line pressure according to a control signal of the shift control unit. A pressure supply control unit controls supply of the line pressure to on-coming and off-going frictional elements of the transmission. The method outputs a first value of a line pressure control duty if the power-on downshift is requested; subsequently outputs a second, lower value of the line pressure control duty if a first shifting is started during outputting of the first value; and subsequently outputs the first value if a turbine speed is greater than or equal to a predetermined speed.

Abstract: A pressure medium supply unit for a hydraulic system of a motor vehicle that includes a clutch requiring a high hydraulic pressure and a low volumetric flow rate of hydraulic fluid for operation, and an automatic transmission requiring a low hydraulic pressure and a high volumetric flow rate of hydraulic fluid for operation. A single hydraulic pump is provided to supply hydraulic fluid to both the clutch and the transmission.

Abstract: There is provided a shift control device for an automated manual transmission having power transmission lines equipped with respective start clutches and gears. The shift control device includes clutch actuation mechanisms and a transmission shift controller that causes the clutch actuation mechanisms to regulate the clutch engagement forces applied to the start clutches so as to perform clutch changeover upon gear selection for a desired gear range in response to a transmission shift command. Each of the clutch actuation mechanisms has primary and secondary clutch engagement force regulation units.

Abstract: A hydraulic control apparatus and method of controlling it for an automatic dual clutch transmission, which includes a first clutch with a first partial transmission and a second clutch with a second partial transmission, as well as a shifting system for engaging/releasing gears of the two partial transmissions. A first switching valve in a first position AI connects a first pressure regulator to the first clutch and disconnects it from the shifting system and in a second position BI connects the first pressure regulator to the shifting system and disconnects it from the first clutch, and that a second switching valve in a first position AII connects a second pressure regulator to the second clutch and disconnects it from the shifting system and in a second position BII connects the second pressure regulator to the shifting system and disconnects it from the second clutch.

Abstract: The two stage check valve for the automatic transmission system provides a first member that opens in response to a first pressure and a second member which opens in response to a second pressure where the second pressure is higher than the first pressure.

Abstract: A more efficient method for maintaining the hydraulic actuation of a selectively engageable torque transmitting device in a vehicle. The method includes generating a predetermined pressure level of a hydraulic fluid such as, for example, with a pump. The pressurized hydraulic fluid is transferred through an open valve and to a selectively engageable torque transmitting device such that the selectively engageable torque transmitting device is engaged. Thereafter, the valve is closed so that the predetermined pressure level of hydraulic fluid at the selectively engageable torque transmitting device remains relatively constant. Accordingly, the selectively engageable torque transmitting device remains engaged without continuously generating additional pressure such that the fuel economy of the vehicle is improved. A corresponding apparatus is also provided.

Abstract: A dynamic characteristic of a hydraulic pressure is significantly enhanced since a line pressure control system. A method employed by the system includes determining whether a vehicle is in a power-on state, determining whether a damper clutch is being engaged when the vehicle is in the power-on state, compensating a line pressure duty determined on the basis of an engine torque with a first compensation duty determined on the basis of a vehicle speed and an operation state of the damper clutch when the damper clutch is being engaged under the power-on state, and controlling the line pressure according to the compensated line pressure duty.

Abstract: A system and a method for generating a line pressure of a continuously variable transmission (CVT) in a hybrid vehicle in which the line pressure of the CVT is maintained to be constant even in an idle stop state of an engine. Steps may include detecting operation of a brake; determining whether an idle stop condition is satisfied; detecting a hydraulic pressure of a control valve for controlling the line pressure of the continuously variable transmission when the idle stop condition is satisfied; comparing the hydraulic pressure of the control valve with a predetermined value; generating a pressure difference in the chamber when the hydraulic pressure of the control valve is smaller than or equal to the predetermined value; and actuating a cylinder for generating the line pressure according to the pressure difference in the chamber.

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 hydraulic control apparatus for an automatic transmission provided with a friction engaging element that operates using hydraulic pressure includes a range pressure oil passage which is connected to the friction engaging element; a manual valve which is connected to the range pressure oil passage; a drain port which is formed in the manual valve and which drains hydraulic pressure of the range pressure oil passage; a drain oil passage which is connected to the drain port; and a drain pressure controller which is connected to the drain oil passage and which performs control so as to change a decreasing rate of drain pressure of the drain oil passage.

Abstract: An automatic transmission control device adjusts a hydraulic pressure of a working fluid to generate pressures applied to a plurality of friction elements of an automatic transmission to control the engagement or disengagement of the friction elements. The control device includes a plurality of electromagnetic valves, a plurality of application pressure control valves, a selector, and a line pressure control valve. The application pressure control valves control pressures applied to the friction elements according to the output pressures of the electromagnetic valves. The selector selects the maximum pressure from the output pressures of the electromagnetic valves. The line pressure control valve controls a line pressure according to the output pressure selected by the selector.

Abstract: A line pressure variable control method for an automatic transmission uses a solenoid valve to control a line pressure according to a duty ratio thereof. The method includes determining whether a current shift range is one of forward driving shift ranges, calculating a minimum line pressure based on at least one automatic transmission operating condition if the current shift range is one of the forward driving shift ranges, and calculating a solenoid duty ratio corresponding to the calculated minimum line pressure. Determining whether there is clutch slip, calculating a solenoid correction duty ratio based on an amount of the clutch slip. If it is determined that there is clutch slip, modifying the solenoid duty ratio with the solenoid correction duty ratio and controlling the solenoid valve using the modified solenoid duty ratio.

Abstract: When it has been determined that control for a predetermined upshift has been started while an accelerator pedal was not being depressed, and that a factor that changes an input torque of an automatic transmission has been generated, an engaging pressure of a predetermined hydraulic frictional engagement device is corrected by a correction amount in accordance with the factor that changes the input torque. As a result, undershooting of an engine speed, as well as shift shock which results from that undershooting, is able to be preferably suppressed.

Abstract: A system and method for controlling a transmission with an automotive vehicle is disclosed. The automotive vehicle includes a powertrain control module (PCM) and a governor pressure sensor coupled to the PCM. The system and method comprises a controller system for sensing at least one parameter of the vehicle. The controller system modifies an excitation voltage to the governor pressure sensor based upon the at least one parameter. A system and method in accordance with the present invention compensates the erroneous shift points in a transmission by ramping the excitation voltage based upon engine and vehicle parameters. In so doing, upshift and downshift points are corrected. Furthermore, the settings for the excitation voltage range can be user-specified to accommodate a variety of vehicles.