Abstract: A system for controlling an automatic transmission, mounted on a vehicle and connected to an engine, includes a plurality of sensors for sensing vehicle operating conditions. The automatic transmission also includes a plurality of friction elements such as a front clutch and a rear clutch, and the system includes a plurality of shift valves for hydraulically actuating the friction elements to selectively achieve one of a plurality of speed stages. A first and second shift solenoid control the operation of a shift control valve which in turn controls the operation of the shift valves. One of the shift valves, a rear clutch valve, controls the operation of the rear clutch, and a rear clutch solenoid is provided to control the operation of the rear clutch via the rear clutch valve. The rear clutch solenoid controls the rear clutch independently of the control operations performed by the first and second shift solenoids.

Abstract: A hydraulic control system for an automatic transmission to establish a predetermined stage by applying a first frictional engagement element and releasing a second frictional engagement element, comprising: a first hydraulic servo for actuating the first frictional engagement element; a second hydraulic servo for actuating the second frictional engagement element; change-over means for switching the feed of an oil pressure to the first hydraulic servo; signal pressure generating means for generating a signal pressure; and a pressure regulator valve for regulating the pressure to be fed to the second hydraulic servo.

Abstract: A shift capacity control system for an automatic transmission is constructed to determine a state of an engine speed difference after occurrence of a shift command, determine a propriety of a shift capacity of the automatic transmission in response to the state determined, and control an engagement capacity of a friction element to be operated during a period of shifting in response to the propriety determined.

Abstract: If there is a need to accelerate abruptly, or shift a speed stage from a fourth speed stage to a second speed stage, to accomplish a skip shift from the fourth speed stage to the second speed stage without going via a third speed stage and, therefore, enhance the shift-responsiveness and the power performance, a high-low pressure valve which is connected to a fourth friction pressure line in the third and fourth speed stages is duty controlled by a damper clutch solenoid valve to vary a line pressure in a pressure regulating valve with the operation of a damper clutch, and a shift valve is controlled to a drive pressure passage and a third speed line pressure by controlling a first and second pressure control solenoid valves to enable the skip shift, and by supplying a first friction element with the operation pressure at times of the second to the third speed stage shifting, after the shifting to the third speed stage, when the operation pressure for the fourth friction element is supplied to a releasing val

Abstract: The automatic transmission equipped with the control system of this invention is combined with a coupling for transmitting the rotation of the engine to the transmission and includes: a clutch which is applied when a forward running range is selected; a hydraulic servo which receives an oil pressure for applying the clutch; and a hydraulic control unit for controlling the oil pressure to the hydraulic servo.

Abstract: An automatic transmission system for automotive vehicle includes a hydraulic pump for pressurizing fluid, a pressure regulating valve for varying hydraulic pressure supplied from the hydraulic pump, nine friction elements activated by drive pressure or reverse pressure supplied from a manual valve, first and second shift control sections having at least two shift valves for supplying hydraulic pressure to the friction elements, selectively, and a torque pressure converting section for supplying torque pressure to the first shift control section. The system performs five forward speeds and one reverse speed. Two solenoid valves are adopted to control four shift valves and control is performed sequentially such that the construction of the system can be simplified and the shift feeling can be improved.

Abstract: Disclosed is a hydraulic control system of an automatic transmission for an automotive vehicle.

Abstract: The present invention is directed toward determining when a clutch of an automatic transmission substantially fills with fluid. Once it is accurately determined when a clutch fills with fluid, then control over the transmission shifting may reliably be performed. The present invention determines when an on-coming speed clutch substantially fills with fluid in response to determining when an off-going speed clutch releases. Further, the present invention determines when an on-coming direction clutch substantially fills with fluid in response to determining when the torque converter output torque suddenly changes.

Abstract: An arrangement for controlling an automatic selector device of a change-speed gearbox has two selecting connections engageable alternately by selecting actuators operated by pressure medium can be actuated into two non-transient and two transient selector conditions. This alternate engageability is provided by an electronic control unit by way of just one electromagnetic control valve. The arrangement also uses three pressure systems and two multi-way valve arrangements.

Abstract: A controller for an automatic transmission which reduces wear of frictional engagement elements and shortens gear change time even when a gear change jump is made. The controller of the present invention includes a first hydraulic servo to which oil is supplied to make a gear change jump, a second hydraulic servo to which oil is supplied to make a gear change to an intermediate gear stage, a limited supply oil circuit having an oil flow limiting element, a quick supply oil circuit bypassing the oil flow limiting element and a pressure governor for regulating a line pressure to supply oil at a controlled pressure to the quick supply oil circuit. An oil path switching valve switches oil supply, to the first hydraulic servo or the second hydraulic servo, between the limited supply oil circuit and the quick supply oil circuit.

Abstract: A hydraulic control system of an automatic transmission for an automotive vehicle includes a hydraulic pump, a pressure regulating valve, a torque converter, a converter clutch, first, second and third solenoid valves, first through eighth friction elements, second and third speed clutch valves, a band valve and a manual value. The pressure regulating valve varies a hydraulic pressure when shifting, and the converter clutch regulator valve actuates a damper clutch to improve transmission efficiency of the torque converter. The first, second and third solenoid valves supply or obstruct the supply of hydraulic pressure from the pressure regulating valve to a respective one of a first, second and third clutch shift valve to displace valve spools of a respective one of the first, second and third clutch shift valves. The second speed and third speed clutch shift valves as well as the fourth speed band valve, selectively supply hydraulic pressure to the friction elements to perform shifting.

Abstract: A control apparatus for a hydraulically operated vehicular transmission having a plurality of hydraulic engaging elements has an accumulator which is connected in parallel with a hydraulic engaging element for a low-speed transmission train and a back pressure generating source which generates a hydraulic oil pressure to be supplied to a back pressure chamber of the accumulator. The control apparatus includes a changeover valve which can be changed over between a first position in which the back pressure chamber of the accumulator and the back pressure generating source are brought into communication with each other and a second position in which the communication is cut off to lower a pressure in the back pressure chamber. The changeover valve is arranged to be changed over from the second position to the first position when a hydraulic oil pressure in the hydraulic engaging element for the low-speed transmission train has exceeded a predetermined pressure.

Abstract: A hydraulic control system for an automatic transmission of automotive vehicles is provided. The hydraulic control system includes a pressure source, a plurality of solenoid valves, and a plurality of directional control valves. Each solenoid valve selectively supplies and release hydraulic pressure to and from one of frictional element of a power train of the automatic transmission according to a given schedule of transmission operation for establishing a given gear ratio. The directional control valves are interposed between the frictional elements of the power train and the solenoid valves, respectively.

Abstract: The present invention relates to an adaptive control method for an automatic transmission. The method includes the steps of:(a) commanding a predetermined clutch to fill in accordance with a plurality of clutch fill parameters;(b) determining the actual time to completely fill the clutch;(c) comparing the actual fill time with a predetermined fill time; and(d) adjusting at least one of the plurality of clutch fill parameters in response to the comparison in order to modify the clutch fill period during subsequent shifts to the predetermined clutch. Accordingly, the present invention adapts future shifts based on past shifts to improve the shift quality of the transmission.

Abstract: A shift control system of an automatic transmission includes a first element which is to be released in a shift operation, a second element which is to be engaged in the shift operation, and a target shift time set section for setting a target time period of the shift operation needed for releasing the first frictional element and engaging the second frictional element. A shift time calculation section is provided for obtaining an actual time period of the shift operation needed for releasing the first frictional element and engaging the second frictional element, and a releasing pressure control section is provided for receiving output of the target shift time set section and the shift time calculation section for controlling a releasing pressure of the first frictional element in the shift operation based on the difference between the target and actual time periods of the shift operation.

Abstract: A valve is provided in one of the accumulator oil passageways provided between the servo and the 2-3 shift valve of an automatic transmission to partially restrict or control the flow of oil to and from the servo and clutch, thus adjusting the timing of shifts from second to third gear. The added valve or metering device would allow for a size increase of an orifice from the manual valve while maintaining proper timing of the apply/release of the 3-4 clutch and 2-4 band. The invention allows larger oil volume for both apply/release of the 3-4 clutch and 2-4 band, decreasing clutch failures and increasing transmission life expectancy. The invention is particularly advantageous with THM 700-R4 and 4L60-E automatic transmissions for 4-, 6- or 8-cylinder vehicles.

Abstract: A control system for an automatic transmission, includes a first hydraulic servo adapted to be fed with oil for effecting a shift to a target gear stage; a second hydraulic servo adapted to be fed with the oil for effecting a shift to the target gear stage; a limit oil feed circuit formed through an oil limit flow limiting device; a quick oil feed circuit bypassing the oil flow limiting device; and an oil passage switch for switching and connecting the limit oil feed circuit and the quick oil feed circuit to the first hydraulic servo and the second hydraulic servo. The oil passage switch feeds oil from the quick oil feed circuit to the first hydraulic servo and the second hydraulic servo, when the engine load is high, and feeds oil from the limit oil feed circuit to at least the first hydraulic servo when the engine load is low.

Abstract: A hydraulic control system for a power train including a shift speed mechanism, a frictional element for switching a shift characteristic of the shift speed mechanism, a hydraulic control mechanism for controlling a hydraulic pressure, a target shift time setting device for setting a target shift time based on an input speed difference of the shift speed mechanism through the shift operation and an input torque introduced to the shift speed mechanism, an angular acceleration calculator for calculating an angular acceleration of an input member of the shift speed mechanism based on the target shift time obtained through the target shift time setting device and the input speed change of the shift speed mechanism through the shift operation, an inertia hydraulic pressure setting device for setting an inertia hydraulic pressure for coping with a moment force due to a moment of inertia of a power transmitting system to the shift speed mechanism based on the angular acceleration of the input member of the shift spe

Abstract: A shift control system for an automatic power transmission is capable of optimizing operation timing of a timing valve and whereby eliminate a shift-shock and occurrence of racing.

Abstract: A control system for an automatic transmission includes a shift gear mechanism for shifting respective shift gear stages, a shift line map including upshift lines and downshift lines, and a device for detecting a shift timing at which an shift operation should be carried out based on an engine load on the shift line map and a possibility is estimated that a driving condition will return back to the previous shift gear stage. The system also includes an engine load detecting device for detecting a stable condition of the engine load, and a controller for controlling the shift gear mechanism based on the shift line map after the engine load detecting device detects the stable condition of the engine load at the shift timing detected by the shift timing detecting device.

Abstract: An electronic transmission coastdown shift control method in which the transmission controller has the capacity to predict timing of apply element application. The control method of the present invention improves the shift sequence by accurately prefilling the apply element. The transmission controller vents the release element when apply element application is imminent and controls the application of the oncoming element to achieve a controlled element exchange for a smooth coastdown shift. A duty cycle is then applied to complete the oncoming element application with a soft yet quick application and control the engagement of the oncoming element. The identification of the application point of the oncoming element enables the apply element fill volume to be learned during coastdown shifts. It also enables the calculation of a line pressure correction factor necessary in accurately predicting application of the apply element. Anticipation of a coastdown tip-in condition is also provided.

Abstract: A system and method for controlling the clutches in a vehicle powershift transmission. The control system includes a microprocessor which periodically executes an algorithm and which has a memory in which is stored a sequential set of time reference values and a sequential set of pressure values. The control system applies to each oncoming element a fill pressure pulse for fill periods which are unique for each element. The control system determines shift time values, subsequent to filling of the control elements, as a function of the fill period. The control system applies pressure signals to the control elements at times represented by the shift time values which are unique for each element. The control system determines, subsequent to a realignment time, realignment shift time values which are the same for all of the control elements.

Abstract: During downshift operation of an automotive automatic transmission in which a lower-speed clutch for establishing a lower-speed gear is engaged while a higher-speed clutch, which has established a higher-speed gear, is disengaged, to increase the turbine rotational speed Nt toward a synchronous rotation speed Ntj associated with the lower-speed gear, speed change control is carried out according to the same control method regardless of whether the engine is in a power-on or power-off state. A target change rate (Nir)' of turbine rotational speed associated with the higher-speed clutch and a target change rate (Nia)' of turbine rotational speed associated with the lower-speed clutch are set, and a change rate (Nt)' of the turbine rotational speed is detected. The transmission torque through the higher-speed clutch is controlled in a feedback manner such that the detected change rate (Nt)' coincides with the change rate (Nir)'.

Abstract: A multiple stage automatic transmission includes a main transmission mechanism, a sub-transmission mechanism connected with the main transmission mechanism to for introduction of a torque therefrom, and a frictional element connected with the sub-transmission. The engaging force of the frictional element is changed at least by two steps in accordance with a shift mode without changing a hydraulic pressure applied for actuating the frictional element. A shift shock, therefore, can be obviated.

Abstract: An improved adaptive transmission pressure control in which cumulative adaptive corrections are stored in a multi-cell memory array, the cells being associated with specified contiguous ranges of a vehicle operating parameter, such as engine throttle position. Periodically determined adaptive correction amounts are applied to a selected cell which includes the engine throttle setting measured at the initiation of the shift and to two or more cells associated with contiguous engine throttle ranges. In this way, a relatively large number of cells may be employed to minimize approximation errors, while maintaining a cell-to-cell continuum of pressure correction values. In operation, an electro-hydraulic pressure regulator is controlled as a combined function of a predefined pressure command obtained from a normal table look-up and a cumulative correction amount obtained from the memory array.

Abstract: In a control system for an automatic transmission, when successive order signals are emitted so that shift changes are accomplished over multiple shift stages, a shift change ordered by an initial order signal is carried out before a shift change ordered by a last order signal is carried out if a shift gear mechanism has already started its operation. However, a shift change ordered by a last order signal is carried out, without shift changes ordered by an initial order signal and intermediate order signals being carried out, if the shift gear mechanism has not started its operation.

Abstract: A shift control system for obtaining a smooth shift feeling in a shifting necessitating redeployment of friction elements. The shift control system is comprised of a sensor which detects a state that disengagement pressure of a friction element to be disengaged almost becomes zero during shifting. In reply to the detection of the sensor, a controller adjusts engagement pressure of the other friction element to be engaged at a predetermined value determined according to input torque and gear ratio.

Abstract: An automotive automatic transmission includes a one-way clutch and solenoids which, when switched in ON-OFF manner, induces a speed change of the transmission. The rotation speed ratio between input and output shafts of the transmission is obtained. When a speed change becomes necessary, a judgment is carried out as to whether the necessary speed change is of a type which needs the engaged condition of the one-way clutch or not. If the speed change needs the engaged condition of the one-way clutch, switching of the solenoids is carried out when the rotation speed ratio comes to a predetermined value, while, if the speed change does not need the engaged condition of the one-way clutch, switching of the solenoids is carried out when a predetermined time is passed from the time when the necessity of the speed change is made.

Abstract: A control system is provided for servo hydraulic pressure in an automatic transmission having planetary gear mechanisms. First and second frictional engagement devices, whose servo pressures are reversed in feed/drain relationship between desired two high speed stages, are controlled by a shift valve and a directional control valve. The shift valve is switched by a first solenoid. The directional control valve is interposed in a servo hydraulic pressure feed/drain line communicating the shift valve with the first frictional engagement device and is controlled by a second solenoid. The first and second solenoids are controlled by an electronic control unit in accordance with a shift position detected by a detector, whereby the timings of feed or drain of the servo hydraulic pressures to or from the first and second frictional engagement devices are changed by predetermined relative amounts, respectively.

Abstract: An automatic transmission shift control system includes a hydraulically controlled valve mechanism for connecting and disconnecting a supply of hydraulic pressure to frictional coupling elements. Connection and disconnection of the hydraulic pressure supply locks and unlocks the frictional coupling elements in order to automatically shift an automatic transmission into desired gears. A time regulator regulates a duration time for which the valve mechanism is kept actuated and with which a speed at which the frictional coupling element is locked changes. The time regulator is controlled so as to variably regulate the duration time according to conversion efficiency of a torque converter. This conversion efficiency is, for example, determined from a speed conversion ratio and a torque conversion ratio.

Abstract: A method is provided for the control of servo hydraulic pressure in an automatic transmission. Servo hydraulic pressure is adapted to engage or release first and second frictional engagement elements arranged in such a relationship that, upon shifting from one particular speed stage to another, one of the first and second frictional engagement elements is released while the other is engaged. The servo hydraulic pressure, engaging one frictional engagement element, is linearly lowered in a torque phase during a shift so it releases the one frictional engagement element, responsive to a rise in the servo hydraulic pressure to the frictional engagement element to be engaged, to maintain an inversely proportional relationship between the servo hydraulic pressure being raised and that being released.

Abstract: In a certain speed stage shifting of an automatic transmission of a vehicle including a speed change gear mechanism including rotary members such as gears and gear carriers and hydraulically operated friction engaging brakes and clutches adapted to provide various speed stages according to selective engagement and disengagement of the friction engaging brakes and clutches, the servo oil pressure of a first friction engaging brake is immediately lowered down to a stand-by pressure marginally higher than a threshold pressure bordering non sliding and sliding of the first friction engaging brake at the start of a change-over of a second friction engaging brake is and then, when a substantial change-over of the second friction engaging means started, the servo oil pressure is further lowered across the threshold pressure and thereafter periodically lowered by a decrement the magnitude of which may desirably be increased along with a lapse of time.