Abstract: The method of controlling a pressure control solenoid valve which controls hydraulic pressure in a hydraulic control system for an automatic transmission of a vehicle first senses a plurality of vehicle operating conditions, and detects a power-on vehicle operating state based on the sensed vehicle operating conditions. Next, the method controls a duty ratio of the pressure control solenoid valve according to predetermined values corresponding to the power-on state when the power-on state detected. The method then detects a change in the vehicle operating state from the power-on state to a power-off state. Upon detection, the method generates an initial duty ratio for the pressure control solenoid valve based on a predetermined duty ratio corresponding to the power-off state and duty ratios supplied to the pressure control solenoid valve during the power-on state. The pressure control solenoid valve is then controlled according to this initial duty ratio during the power-off state.

Abstract: In order to precisely determines the time to start feedback control of line pressure during a shifting period, a shift control computer calculates an effective gear ratio Ge=Nt/Nos at the time of an shift instruction based on input shaft rotational speed Nt and detected vehicle speed Nos and then calculates a parameter F=Nos.times.Ge-Nt indicating the point to start feedback control based on the input shaft rotational speed Nt, the detected vehicle speed Nos and the effective gear ratio Ge. By comparing the calculated parameter F with a predetermined value .DELTA.Nt, hydraulic pressure at the start of shift operation is maintained if F<.DELTA.Nt and, if F.gtoreq..DELTA.Nt, feedback control is performed to cause the input shaft rotational speed Nt to vary in a predetermined manner.

Abstract: Apparatus for controlling the amount of slip of a lock-up clutch of an automotive vehicle, which is provided in a fluid-operated power transmitting device such as a torque converter disposed between an engine and an automatic transmission, for direct connection of the engine and the automatic transmission, the apparatus including a pressure regulating valve for regulating a line pressure depending upon a load of the engine, a lock-up clutch slip control valve operable in a slip control mode for receiving the regulated line pressure and regulating a hydraulic pressure applied to the lock-up clutch to control the amount of slip of the lock-up clutch, a slip control mode detecting device for detecting an operation of the lock-up clutch slip control valve in the slip control mode, and a line pressure change restricting device for restricting an operation of the pressure regulating valve to restrict a change of the line pressure with a change in the engine during operation of the lock-up clutch slip control valve

Abstract: To optimize the application hydraulic pressure of the friction application elements in the transmission mechanism, and to reduce the unnecessary load on each member, the transmission mechanism of an automatic transmission is provided with a plurality of friction application elements which are applied simultaneously in order to achieve the designated gear stage, and hydraulic servos which operate the friction application elements independently. The control apparatus has an information detecting means, an input torque calculating means which calculates the input torque of the transmission mechanism on the basis of this information, an application hydraulic pressure calculating means which calculates the necessary application hydraulic pressure required to maintain the application of each individual friction application element on the basis of the input torque, and a supply means which supplies the necessary application hydraulic pressure to the hydraulic servos of the friction application elements.

Abstract: A control system for an automatic transmission having at least a friction coupling element which is coupled with a hydraulic pressure increasing by way of a leveled transitional pressure has an accumulator which discharge a high level of pressure accumulated therein into the friction coupling element during a gear shift under the condition where the line pressure is low.

Abstract: A system for controlling a pump in a hydraulic circuit for an automatic transmission, having a viscosity insensitive fixed orifice and a relatively high resistance laminar orifice connected in series relationship between a vent port and a control pressure supplied to a secondary regulated pressure SRP valve. At relatively low temperature, flow through the laminar orifice is negligible; therefore, the steady-state differential pressure across the fixed orifice is negligible. At relatively higher temperatures, flow through the laminar orifice increases. A pressure divider is established and the feedback differential pressure is reduced in proportion to the hydraulic resistance of the two orifices. Flow to friction elements from a primary pump and auxiliary pump and return of fluid to the inlets of the pumps is controlled through a clutch capacity pressure regulator valve acting in cooperation with the SRP valve.

Abstract: A controller (100 in FIG. 1) for relieving a gear shift shock in a vehicle, comprising an input torque calculation portion (131) which calculates the input torque (T.sub.t) of the stepped automatic transmission mechanism of the vehicle from engine r.p.m. (N.sub.e) and turbine r.p.m. (N.sub.e), a shift start recognition portion (134) which recognizes the real mechanical shift start timing of the stepped automatic transmission mechanism in accordance with the change of the input torque (T.sub.t), a line-pressure correction magnitude calculation portion (142) which calculates a line-pressure correction magnitude (.DELTA.PL) during the gear shift operation of the stepped automatic transmission mechanism when the shift start has been recognized, a standard line pressure calculation portion (143) which calculates a standard line pressure (PL), and a command line pressure calculation portion (144) which adds the line-pressure correction magnitude (.DELTA.

Abstract: A system for carrying out shift control of an automatic transmission in accordance with a rotational speed of an input shaft thereof during shifting comprises calculating an input torque coefficient in accordance with torque of the engine detected and a rate of time change calculated, converting the input torque coefficient calculated into a velocity ratio, calculating a rotational speed of the input shaft of the automatic transmission in accordance with the rotational speed of the engine detected and the velocity ratio, and carrying out torque-down of the engine in accordance with the rotational speed of the input shaft calculated.

Abstract: A control system for an automatic transmission of an engine equipped with a traction control which causes a drop in engine output by retarding ignition timing regulates line pressure of the hydraulic control circuit on the basis of engine output torque determined according to an advance angle of ignition timing when the traction control is not executed or on the basis of engine output torque, which is lower than that before execution of the traction control and higher than that after execution of the traction control, estimated on the basis of a basic advance angle of ignition timing when traction control is executed.

Abstract: An automatic transmission learning control apparatus comprises a memory for storing parameters in memory locations specified for respective throttle valve position ranges. A physical quantity related to a gear shift operation made in an automatic transmission is measured. The parameter stored in the memory location specified by the throttle valve position range including the sensed throttle valve position is updated in a direction to bring the measured physical quantity into agreement with a target value. The parameter stored in the memory location specified by the throttle valve position range including the existing throttle valve position is used to control the gear shift operation. The throttle valve position ranges have a smaller width for a throttle valve position causing a greater rate of change of a torque inputted to the automatic transmission with respect to a throttle valve position change.

Abstract: A method of establishing an adaptive pressure term in an automatic transmission having a pressure command developed from a base line pressure term and an adaptive pressure term extends implementation of adaptive pressure corrections during non-ideal periods of operation such as low temperatures, short operating cycles and driver variations by establishing an adaptive pressure term proportional to a measure of confidence in a pressure correction term calculated at each ratio change of the transmission. The measure of confidence is determined according to a variety of functions of predetermined powertrain operating parameters and measures of criticality.

Abstract: A vehicle automatic transmission control system, in which when a gear to be shifted to is determined in response to the throttle opening and vehicle speed, hydraulic oil is supplied to a clutch for the gear to be shifted to. In an early period of the gearshift, the hydraulic oil is supplied to decrease a time lag between an output of the gearshift command and a start of clutch engagement. In the system, there is provided, instead of an expensive oil pressure sensor, a means for estimating or detecting the clutch oil pressure as a capacity of power which the clutch can transmit. When the estimated or detected pressure is high, the supply of oil to the clutch is prohibited so as to prevent sudden clutch engagement which would otherwise produce shock.

Abstract: Disclosed is the hydraulic control system of an automatic transmission for a vehicle which can effectively control a power train even though all of one-way clutches is omitted to simplify the power train structure, including a hydraulic pump which is operated by power of an engine to produce a line pressure; a manual valve cooperating with a shift selector lever; a torque converter control part; a pressure regulator part for regulating the line pressure, the pressure regulator part being controlled in accordance with ON/OFF operations of solenoid valves; a pressure control part which is controlled by the line pressure from the pressure regulator part to thereby control a flow of a hydraulic pressure fed from the manual valve; and a shift control part for selectively feeding the hydraulic pressure fed from the pressure control part to each friction member.

Abstract: A hydraulic control system for an automatic transmission comprising a shift speed mechanism, a frictional element hydraulically controlled for switching a power transmitting path in the shift speed mechanism, a working pressure controller for controlling an engaging force of the frictional element during a shift operation by adjusting a working pressure applied to the frictional element, a calculator for calculating separately an input torque pressure corresponding to an input torque introduced to the shift speed mechanism and an inertia torque pressure corresponding to an inertia torque which is changed in accordance with a speed change of the shift speed mechanism, and a learning control compensator for compensating the inertia torque pressure by means of a learning control. The shift shock is effectively suppressed irrespective of the change of the vehicle operating circumstance.

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: Disclosed is a hydraulic control system of an automatic transmission used in a vehicle, which comprises a torque converter for transferring the engine power to the input shaft of the transmission, an oil pump for pumping an oil by means of the engine power, a pressure regulation means for regulating the line pressure produced by the oil pump according to the forward and reverse drive and the amount of a throttle opening, a damper clutch working control means for changing the direction of the pressure delivered to the torque converter in order to increase the power transfer rate of the torque converter, a shift pressure control means for delivering the pressure supplied from the pressure regulation means to the first, second, third, fourth, fifth, sixth and seventh solenoid valves controlled on/off by a transmission control unit to adjust the control pressure during shifting operation, and a pressure distribution means for selectively distributing the pressure supplied from the pressure control means during sh

Abstract: Disclosed is a hydraulic control system of an automatic transmission used in a vehicle, which includes an oil pump, a manual valve for selecting one of the parts of a hydraulic pressure line to deliver the hydraulic pressure produced by the oil pump according to the vehicle speed range, a first to a fourth pressure control valve with a first port to receive the pressure supplied by the manual valve in a forward drive range, a first to a fourth solenoid valve for respectively controlling the pressure control valves according to a vehicle speed, a rear clutch valve for receiving a hydraulic pressure from the pressure control valves, a low/reverse valve, a fail-safe valve, and a high-low pressure valve for receiving a hydraulic pressure from the fourth pressure control valve to vary the line pressure.

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: A method for controlling preferably an electro-hydraulic automatic transmission of a motor vehicle fitted with a combustion engine provides a gradual kick-down while braking. In particular the kick-down is performed when, in the course of approaching a bend, a condition is activated, which prevents upshifting. The upshift prevention is initiated when the accelerator pedal is released quickly during shearing action. The upshift prevention stops if after an interval, upon detection of tensile action, the vehicle does drive round a bend. The upshift prevention is followed by a gradual adaptation of the gear level to the shift parameter.

Abstract: A system for controlling a downshift in an automatic transmission having a torque converter includes friction elements for alternately producing a drive connection between components of a planetary gear set and disengaging the connection, a valve body adapted to connect a source of high pressure hydraulic fluid to the friction elements, a solenoid for controlling operation of the hydraulic valves, a microprocessor having a memory containing control algorithms, sensors producing signals representing the speed of the transmission output shaft and turbine shaft, a sensor producing a signal representing the position of an engine throttle, the control algorithms controlling a downshift of the transmission.

Abstract: An automatic transmission control system has first and second hydraulic circuits leading to a low/reverse brake and a reverse clutch, respectively, which perform supplying and discharging of hydraulic pressure to the low/reverse brake and reverse clutch, respectively, so as to lock and unlock them. The first circuit is provided, from the upstream end, with an orifice for restraining hydraulic pressure, an accumulator disposed downstream from the orifice for pressure accumulation, and a switching valve for switching supply and discharge of the hydraulic pressure. The second hydraulic circuit is provided, from the upstream end, with a switching valve for switching communication of the first hydraulic circuit between the orifice and switching valve with the second hydraulic circuit and communication of the first hydraulic circuit upstream from the orifice with the second hydraulic circuit.

Abstract: A hydraulic circuit for a lock-up device includes a valve arranged in an oil path for supplying hydraulic pressure to a hydraulic power transmission. The valve regulates flows of hydraulic oil discharged toward a cooling circuit or a lubricating circuit, corresponding to a signal in relation to an engine torque. Therefore, corresponding to the engine torque, it is possible to maintain the hydraulic pressure for the hydraulic power transmission, which is necessary for lock-up condition of the lock-up device.

Abstract: A technique for controlling the rate of engagement of a friction element in response to a commanded change in operating range of an automatic transmission. Hydraulic pressure at a blip magnitude fills the hydraulic cylinder of a friction element. The pressure magnitude at the base of a pressure ramp and a magnitude at the top of the ramp are calibrated over a range of transmission oil temperature for each type of range change required by the vehicle operator. The calibrations minimize the length of engagement and produce a smooth engagement. Execution of an algorithm produces a high level of pressure magnitude on the basis of these calibrated values, a step down at the base of a ramp, a rate of increase during the period of engagement, and a maximum pressure at the top of the ramp.

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: In an electronic-hydraulic control mechanism of an automatically shifting motorcar transmission, control valves (88, 70, 65, 67, 91 and 94) are coordinated with actuation devices (81 to 87) of hydraulically engageable and disengageable friction clutches or brakes (A to E1). The pressure level in one main pressure system of the control mechanism is regulated by a main pressure valve (29) while a control unit (72) designed as microprocessor controls the actuation devices via electrically actuated solenoid valves (41, 42 and 43) and pressure-control valves (38, 39 and 40) in accordance with operation parameters of the motorcar transmission and of a drive engine, the same as of a shift and/or travel program control.

Abstract: A control system for controlling both: an engine having a plurality of cylinders, a plurality of intake ports formed individually for the cylinders, a plurality of intake valves for opening or closing the intake ports individually for the cylinders, and a control valve for opening or closing one of the intake ports of each of the cylinders; and an automatic transmission connected to the engine. The control system comprises: a valve controller for opening the control valve, when an engine load is high, and for closing the control valve when the engine load is low: an air/fuel ratio controller for making an air/fuel ratio when the control valve is closed higher than that when the control valve is open; and a shift inhibitor for inhibiting the shift in the automatic transmission till a predetermined time period elapses after the switching of the control valve.

Abstract: A lubrication system for multi-plate clutch assemblies is controlled to provide increased lube flow. During steady state operation, lube flow is increased periodically for a short time interval. At other times during steady state operation, the lube flow is maintained at a level requiring minimum fluid flow for the system.

Abstract: A hydraulic control apparatus for an automatic transmission of a motor vehicle, which has a plurality of gear positions that are selectively established by selective operation of hydraulically operated frictional coupling devices. The apparatus includes a pressure regulating device which receives a hydraulic pressure generated by a pressure source and generates a line pressure to be applied to the coupling devices. The pressure regulating device regulates the line pressure on the basis of the detected throttle opening angle of the engine when the vehicle is running in a transient state, and on the basis of the detected intake air quantity of the engine when the vehicle is running in a steady state.