Abstract: Disclosed is a hydraulic control system.

Abstract: In a hydraulic control system for an automatic transmission of multiple clutch type for use in a motor vehicle, a shift valve which inverts the supply and cutoff of working oil for a hydraulic actuator serving to change-over gear shift stages is provided with a spool valvule and a clutch-oil-pressure supply port (as shown in FIG. 1). Even when a solenoid valve for controlling the shift valve has failed, a clutch oil pressure is supplied from the clutch-oil-pressure supply port so as to hold the switchover position of the spool valvule and to keep the gear shift stage already established. Thus, the hydraulic control system prevents an engine speed from rising or the motor vehicle from locking due to the failure of the solenoid valve.

Abstract: An oil pressure control system for an automatic transmission for controlling the oil pressure of a frictional engagement element by a regulator valve for outputting an oil pressure according to a signal pressure inputted. The oil pressure control system comprises: a first solenoid valve for outputting a signal pressure varying with an electric signal; and a second solenoid valve having a coil of a higher resistance than that of the first solenoid valve and for applying, when activated, a signal pressure in the same direction as the signal pressure of the first solenoid valve to the regulator valve. As a result, it is possible to accurately control the oil pressure at the transient time of a speed change of the frictional engagement element of the automatic transmission and to prevent the controlling solenoid valves from being damaged.

Abstract: A hydraulic control system of an automatic transmission for a vehicle comprises a pressure regulator means changing hydraulic pressure supplied from an oil pump, a torque pressure changing/supplying device changing line pressure supplied from the pressure regulator into a torque pressure and supplying it, a shift controller supplying the hydraulic pressure through a drive pressure line in D range and through a rear pressure line in R range, a hydraulic pressure distributing device selecting and supplying the hydraulic pressure supplied from the shift controller by the control of the solenoid valves to the first, second, third, fourth, fifth, sixth, seventh friction members, and a plurality of accumulators disposed on the first, fourth, and seventh friction members.

Abstract: A hydraulic control system for an automatic transmission includes a hydraulic pump, a pressure regulating valve, a solenoid supply valve, a manual valve, a torque control regulator valve, a control switching valve, a N-D control valve, a 1-2 shift valve, a 2-3 shift valve, a 3-4 shift valve, and a N-R control valve. Accumulators are disposed in conduits to first and seventh friction members for reducing shift shock caused by line pressure and drive pressure fed from fourth and second clutch valves.

Abstract: An automatic transmission for an automotive vehicle comprises electromagnetic valves 5A-5C activated or deactivated in accordance with a given shift schedule determined based on traveling conditions of the automotive vehicle, a plurality of planetary gear trains 4A-4C driven by an output force of an engine, a plurality of friction devices B1-B4 and C1-C3 receiving hydraulic pressure to selectively connect or fix components constituting planetary gear trains 4A-4C, and a mechanical shift valve 6A having a pair of pressure chambers 62A and 63A and plural ports 64A, 65A and 66A. Upon application of hydraulic pressure to pressure chamber 62A, a fluid communicating path is established in the shift valve 6A so as to connect brake B1 and manual shift valve 8. When hydraulic pressure is applied to both of pressure chambers 62A and 63A, pressurized oil is drained from brake B1.

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: 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 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: In a hydraulic control system for automatic transmissions of a vehicle, drive pressure is fed to a first friction member at the first, second and third speeds of a "D" range, drive pressure is fed to a third friction member at a fourth speed, a 2-4/3-4 shift valve for exhausting pressure from the first friction member at third-to-fourth and second-to-fourth speed shifting is connected to an end clutch valve to allow pressure from a first pressure control valve to be fed to the third friction member at the fourth speed, and exhausting of pressure from a releasing conduit of a second friction member and the third friction member via an exhaust conduit connecting the 2-4/3-4 shift valve and a 2-3/4-3 shift valve during fourth-to-second, fourth-to-first and third-to-second speed shifting is delayed by an orifice.

Abstract: A hydraulic control system of a vehicle automatic transmission includes a torque converter, an oil pump, a pressure regulator, a damper clutch working control means, a manual valve, an N-D control valve, a torque control regulator valve, a control switch valve, a first to second, second to third, third to fourth, and third to second shift valves, a low/reverse clutch valve, a third clutch valve, and a second to fourth brake valve.

Abstract: Disclosed is a hydraulic control system of an automatic transmission for a vehicle, which comprises an oil pressure regulating device for regulating the oil pressure of an oil pump, a manual/automatic shifting device for selecting a shifting mode, a pressure adjustment device for adjusting the hydraulic pressure to make a smooth shifting mode, a damper clutch control device for controlling the damper clutch of a torque converter, and a pressure distribution device for distributing the hydraulic pressure among the friction elements, wherein said pressure adjustment device further comprises an N-D control valve for supplying to the friction elements a duty-controlled hydraulic pressure produced by solenoid valves from the initial hydraulic pressure in the shifting from the neutral range to the drive range, said N-D control valve being switched to make the port change to provide the drive pressure, and a backward torque control regulator valve for making the port change by the duty-controlled hydraulic pressure

Abstract: Disclosed is a shift control system of an automatic transmission used in a vehicle, which includes an oil pump, a line pressure regulator for regulating the hydraulic pressure supplied from an oil pump to the hydraulic control line, a reducing valve for forming a pressure lower than the line pressure, a first to fourth pressure control valves respectively having a first and a second port for receiving a control pressure from the reducing valve, a third port for receiving the line pressure, fourth port for delivering the line pressure to shift valves, wherein there are provided an N-D control valve, a second-to-third shift valve, a third-to-fourth shift valve, a fourth-to-fifth shift valve, and a reverse drive clutch valve to selectively deliver the pressure from the pressure control valves to the first to fifth friction elements and reverse drive friction element.

Abstract: A hydraulic control system of an automatic transmission for an automotive vehicle which may simplify a structure, minimize a shift shock for improving a shift responsiveness, and improve shift quality even in a driven state by a manual range shift and a power off state.

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: A hydraulic control circuit for a hydraulically operated vehicular transmission has at least five forward transmission trains. The hydraulic control circuit is made up of three sets of first through third solenoid valves and three sets of first through third shift valves to be controlled for changeover by the three sets of solenoid valves such that each of the transmission trains is established by changeover combinations of each of the shift valves. The first shift valve controls a condition of communication between an oil supply passage which is in communication with a hydraulic oil pressure source and a first oil passage and a second oil passage which are both on a downstream side of the oil supply passage.

Abstract: A hydraulic pressure control system for an automatic transmission that includes a torque control regulating valve for converting a portion of the hydraulic pressure from an oil pump to a control pressure in accordance with a variation in the torque, and a control switch valve for supplying a torque pressure to a friction member prior to a shift valve being supplied with supply and release pressures for a friction member.

Abstract: An electronic and hydraulic system of a five speed automatic transmission adapted to establish five forward and one reverse gear ratios by way of effecting selective engagement and disengagement of friction elements comprises an oil pump for producing a pressurized working fluid, a manual selector valve manually operated for distributing the working fluid to forward and reverse fluid lines, first to fourth shift valves for directing the working fluid to one of the friction elements, first to fourth solenoid valves associated with the first to fourth shift valves, respectively, for controlling positions of the shift valves in correspondence to a vehicle speed and a throttle opening degree, second to fourth speed valves each position-controlled by the first to third shift valves to change flow path of the working fluid and an overdrive unit valve position-controlled by the fourth shift valve.

Abstract: Shift control valves for controlling the engagement of a transmission friction devices have a solenoid control chamber pressurized to initiate shifting and a latch chamber pressurized to sustain the selective friction device in an engaged position. The latching chamber pressure is delivered through a latch valve which is also solenoid controlled to direct pressure to the chamber when the solenoid is de-energized and to exhaust the latch chamber when the solenoid is energized.

Abstract: A hydraulic control system of a four-speed automatic transmission whereby second-to-fourth skip shifting or fourth-to-second skip shifting is possible. Line pressure is controlled variably to improve the power train efficiency and the response of shifting time during gear shifting. The exhaust port of the pressure control valve, which is controlled by the line pressure varying solenoid valve according to a duty ratio, is selectively opened to control line pressure. First and second pressure control solenoid valves are controlled according to a duty ratio such that the shift valves are controlled by drive pressure and speed line pressure.

Abstract: A hydraulic control system for 4-speed automatic transmission which is controlled by torque control hydraulic pressure in regular succession and can provide a skip shift comprises a fluid pump (32), a pressure regulator valve (34) for regulating the line pressure generated at the fluid pump (32), a plurality of frictional elements (108, 62, 120, 84, 94, 100, 126) actuated by drive hydraulic pressure or reverse hydraulic pressure in accordance with the position of a valve spool of a manual valve (58), a first transmission control portion (D) having at least two valves (78, 86, 98) for supplying hydraulic pressure to at least one of the frictional elements, and a second transmission control portion (E) for selecting at least one of the frictional elements.

Abstract: A shift control system for an automatic transmission including frictional engagement elements to be applied by actuating a piston by an oil pressure. The shift control system comprises: a pressure regulating valve for regulating the oil pressure to be fed to the frictional engagement elements and for controlling the regulated pressure level; a shift detector for detecting a shift to be executed by feeding the oil pressure to the frictional engagement elements; a low-pressure standby unit for setting the regulated pressure level of the pressure regulator valve to such a value during a predetermined time period after the shift has been detected that the oil pressure to be fed to the frictional engagement elements moves only the piston; and a booster for controlling the regulated pressure level so that the oil pressure to be fed to the frictional engagement elements may gradually increase after lapse of the predetermined time period.

Abstract: A diagnosing apparatus for diagnosing a vehicle automatic transmission system including an automatic transmission having frictional coupling devices, and solenoid-operated valves for controlling the frictional coupling devices to shift the automatic transmission according to shift commands generated by a control device, the apparatus including a speed detector for detecting an engine speed of the vehicle, a device for determining a reference range of the engine speed within which the engine speed is expected to fall when the transmission is placed in a position selected by a shift command, a device for determining whether a predetermined running condition of the vehicle is satisfied, and a defect detector for determining whether there exists a defect associated with the automatic transmission system, depending upon whether the detected engine speed is held within or outside the determined reference range when the predetermined vehicle running condition is satisfied.

Abstract: A hydraulic control system of the present invention is provided for improving a responsiveness to a speed change by compleating the speed chang with a torque pressure control hydraulic pressure after initiating the speed change with the drive hydraulic pressure. The hydraulic control system includes an oil pump for generating hydraulic pressure, a pressure regulating valve for regulating the hydraulic pressure to be proper pressure for reverse and drive, five friction elements which receive the hydraulic pressure for drive in accordance with operation of a manual valve, two friction elements which receive the hydraulic pressure for reverse in accordance with operation of the manual valve, first and second shift control parts having at least two shift valves, respectively, to supply the hydraulic pressure to the friction elements, and a torque control hydraulic pressure regulating part for supplying a torque control hydraulic pressure to the first and second shift control parts.

Abstract: A vehicular automatic transmission and control system therefor includes an automatic transmission including a planetary gear unit and a plurality of friction elements for connecting the components of the planetary gear unit selectively to rotary members or stationary members; a hydraulic control unit for selectively switching and controlling oil pressures to be fed to the friction elements; and an electronic control unit for outputting a signal indicating the running state of a vehicle to control the feed of the oil pressures to the friction elements.

Abstract: A rotary switch, used to select the operating range of an automatic transmission, controls solenoid-operated valves corresponding to the selected range to open and close a connection between a range valve and a control pressure source. The valve has three positions and is centered by one compression spring. One position opens the fluid pressure source to a line that is pressurized to produce forward drive, a second position opens a connection between the fluid pressure source and a line that is pressurized to produce reverse drive, and a third position vents those lines to sump. The spring locates the valve at the center position and makes the valve insensitive to tolerances and spring variations. For example, the range valve will not move until a predetermined control force is applied at either end of the valve spool.

Abstract: A rotary switch, used to select the operating range of an automatic transmission, controls solenoid-operated valves corresponding to the selected range. The valves open and close a connection between a range valve and control pressure source. The range valve includes two spools having three positions. The spools are biased apart by a compression spring located between the spools. One valve position opens the fluid pressure source to a line that is pressurized to produce forward drive, a second position opens a connection between the fluid pressure source and a line that is pressurized to produce reverse drive, and a third position vents those lines to sump. The spring locates the spools at the third position. Control pressure force on opposite ends of each spool forces both spools to the first and second positions in response to the range selected by the vehicle operator.

Abstract: A hydraulic control for an automatic transmission is composed of a gear shift mechanism having first and second frictional engagement elements, a hydraulic control unit for the engagement elements, and an electronic control unit for the hydraulic control unit. The first element is engaged to achieve a first speed stage and the second element is engaged to achieve a second speed stage faster than and closest to the first speed stage. The hydraulic control unit has a first directional control valve for switching the feeding and discharge of hydraulic pressure between the first and second engagement elements, responsive to a first solenoid signal from the electronic control unit. A second directional control valve is adapted to be switched by a second solenoid signal from the electronic control unit to achieve a third speed stage yet faster than the second speed stage. The first engagement element has a discharge line connected to a drain line via the second directional control valve.

Abstract: A speed change control method for a vehicular automatic transmission, in which the transmission stage position of the automatic transmission having a plurality of transmission stages is changed to an optimum transmission stage set by fuzzy inference on the basis of parameter values indicative of the operating conditions of a vehicle. If a failure of any of sensors for detecting the parameter values concerned in the fuzzy inference is detected, setting the optimum transmission stage by the fuzzy inference is inhibited, and the optimum transmission stage is set in a speed change control mode which is not dependent upon the broken sensor. Thus, even in case of failure of a sensor, the vehicle can be driven without hindrance and without discomfort to a driver or fellow passengers.

Abstract: A hydraulic latch for directing line pressure alternately to a forward drive circuit and a reverse drive circuit includes three solenoid-operated select valves that direct pressure from a line pressure source to a reverse drive select valve, a forward drive select valve, and two coaxial range control valves. The two drive select valves are interconnected to form a hydraulic latch whose outputs are connected to the range control valve such that either the forward drive friction elements are pressurized, the reverse drive friction elements are pressurized, or none of the friction elements are pressurized.

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: Pulse frequency modulation is used to control brakes and clutches which are operated by fluid pressure actuators controlled by electrically actuated solenoid valves. Short pulse periods for all duty cycles are generated by feedback from the solenoid valve or from the actuator. In one circuit an electrical control triggers a flip-flop which starts solenoid current. Solenoid movement results in back-emf and its effects on the solenoid flux field or current is detected and used as a feedback signal to reset the flip-flop to thereby turn off the current as soon as the valve is operated. In another circuit, a computer control emits a command for a certain pulse period. Actuator pressure or position is monitored to produce a feedback signal to the computer. If the signal is not received, the pulse period is increased for the next pulse command so that a sufficient pulse period will be found. If the magnitude of the actuator response exceeds a threshold, the pulse period is decreased for the next pulse command.

Abstract: A transmission control has a redundancy control for upshift and downshift control of friction torque transmitting devices in a power transmission. The control solenoid valves providing for continued governor and accumulator trim boost in the event of a malfunction, in either the electrical system or the hydraulic system, which affects the governor pressure schedule. A reverse control signal, from a manual valve, is effective to remove the malfunctioning solenoid valve from effective operation in the control.

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: A speed change controller for vehicle automatic transmission is constructed such that a speed change range is selected on the basis of vehicle speed and throttle valve opening, and a speed change position for either a low speed change step or a high speed change step is selected from the speed change range by recognizing/judging the vehicle driving conditions. As a result speed change timing can be appropriately controlled to suit to environmental changes, and speed change control catering equally to the individual needs of a large variety of drivers is possible.

Abstract: In a system for controlling a gear ratio of a multi-step geared or continuously variable automatic transmission of a vehicle, the gear ratio is determined through fuzzy production rules each having one of an ATF temperature, a steering or an engine coolant temperature. For example, the rule regarding the ATF temperature defines such that the gear position should be shifted down if the ATF temperature is high. With the arrangement, when the ATF temperature is high, the gear position is determined in the downshifting direction so that the amount of torque converter slippage can be reduced, whereby avoiding temperature rise in the transmission. And since the engine speed is relatively high at that situation, motive force could be sufficient even climbing a hill.

Abstract: In an electronic control type automatic speed changer equipped with a linear solenoid for controlling the oil pressure of the automatic speed changer, when potential difference is generated between the power ground (PE) and the signal ground (SE), the line pressure of the automatic speed changer does not coincide with the predetermined set value due to erroneous signals generated. In order to compensate for the potential difference between PE and SE, according to the present invention, a PE -SE potential difference compensator is provided in series between a current monitor device and PE, and a solenoid monitor circuit is provided for monitoring the potential of the connection point of the current monitor device and the PE-SE potential difference compensator. Thus even if there is a potential difference between PE and SE, a potential difference proportional to the current actually flowing in the linear solenoid can be detected.