Abstract: An automatic transmission control system is capable of quickly and accurately judging the normal state and faulty state of an input shaft rotation speed sensor and/or an output shaft rotation speed sensor. The system includes an input shaft rotation speed sensor condition judging device for judging whether an input shaft rotation speed sensor detecting a rotation speed NI of an input shaft of the automatic transmission is in a normal or faulty state, an output shaft rotation speed sensor condition judging device for judging whether an output shaft rotation speed sensor detecting a rotation speed No of an output shaft of the automatic transmission is in a normal or faulty state, a multiplying means for multiplying the rotation speed No of the output shaft with a current transmission gear ratio, and comparing and judging means for judging whether the multiplied value is coincident with the rotation speed NI of the input shaft.

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: A control for confirming disengagement of a disengaging gear ratio (GR). Signals indicative of input shaft speed (ES or IS) are compared to signals indicative of output shaft rotational speed (OS) to determine if the quotient of input shaft rotational speed to output shaft rotational speed (IS/OS) remains outside an increasing-sized window (GR.+-.error, GR.+-.2*error, GR.+-.3*error).

Abstract: A control system for an automatic transmission which includes a first speed change unit for executing a predetermined speed change by applying/releasing two of a plurality of frictional engagement elements simultaneously and a second speed change unit capable of executing speed changes in at least two higher and lower stages are connected in tandem. The control system comprises: a speed change abnormality detector for detecting an abnormality in the speed change which is executed by applying/releasing the two frictional engagement elements of the first speed change unit simultaneously; and a first speed change unit speed change inhibitor for inhibiting the speed change, which is executed by applying/releasing the two frictional engagement elements in the first speed change unit, when the speed change abnormality is detected by the speed change abnormality detector.

Abstract: A malfunction judgment system of an oil temperature sensor for detecting a hydraulic oil temperature in an automatic transmission of a vehicle. The system receives an output from the oil temperature sensor to judge a malfunction of the oil temperature sensor when an increase rate of the oil temperature is smaller than a predetermined value in a predetermined time period after the vehicle starts running. A running condition detecting element detects a vehicle running condition. The system further has a plurality of conditions for judging the malfunction of the oil temperature sensor based on the detected running condition of the vehicle and the output of the oil temperature sensor.

Abstract: A slip detecting device detects slipping of a selected hydraulically engaged element of an automatic transmission during non-shifting, and a determining device determines a hydraulically engaged element larger in driving-force transmitting capacity than the hydraulically engaged element which is in its engaged state. A transmission control element then brings the hydraulically engaged element having the larger driving force transmitting capacity, into its engaged state, in place of the hydraulically engaged element which was in its engaged state. Thus, the slipping of the hydraulically engaged element during non-shifting is prevented.

Abstract: An automatic transmission control system for controlling oil pressure of a frictional engagement device in accordance with an input torque to an automatic transmission, comprising: a plurality of input torque estimating devices for estimating the input torque to the automatic transmission; a first oil pressure determining device for determining the oil pressure on the basis of the input torque to the automatic transmission, as estimated by any of the input torque estimating device; a trouble deciding device for deciding a trouble about the input torque value estimated by any input torque estimating device; and a second oil pressure determining device for determining the oil pressure on the basis of the input torque to the automatic transmission, as estimated by another input torque estimating device, if the trouble deciding device decides a trouble about the input torque value estimated by any input torque estimating device.

Abstract: In one aspect of the present invention, a method of effecting shifts in a vehicle is disclosed. The method modifies the transmission shiftpoints in response to the number of upshift successes and failures.

Abstract: A shift valve is proposed for switching the direction of travel of a powershift transmission and, in particular, a tractor, wherein a slide valve (20) fitted in a valve housing (1) can slide into a forward, a reverse or a neutral position. The slide valve (2) can be displaced by electro-hydraulic devices. Centering pistons (21, 22 and 210, 220) are provided in the valve housing (1) which, during normal operation, lie in a withdrawn or non-activated position, but during emergency operation can be hydraulically or pneumatically activated in such a way that they actuate the slide valve (20) while bypassing normal control of the latter.

Abstract: A control system is provided for selectively placing a vehicle transmission in a neutral condition after startup of the vehicle. The transmission is of the type including a plurality of intermeshing gears and associated clutches. The clutches are engageable and disengageable in predetermined combinations in response to energization and de-energization of actuator coils to establish predetermined gear ratios between input and output shafts of the transmission. The control system includes a neutral circuit and a control circuit. The neutral circuit causes a current carrying path through the coils to be interrupted under the control of the control circuit. The neutral circuit preferably also causes the transmission to be placed in a neutral condition upon startup of the vehicle engine.

Abstract: An electronic transmission shift control is provided wherein an input device such as a vehicle control lever is connected to a sensor. The sensor sends out a substantially continuous signal to an electronic control module. The electronic control module controls the current going through a solenoid that, in one application, is controlling the pressure of a valve to engage a clutch in a transmission.

Abstract: A system for controlling oil pressure of an automatic vehicle transmission having a plurality of fictional engaging elements (K1 ,K2,K3,B 1 ,B2) installed in the transmission for establishing a gear, a plurality of solenoid valves (SA and SE) at least one (SA) of which opens to supply the pressurized oil to at least one (K1) of the frictional engaging elements. The system also as a manual valve (20) whose spool moves in response to the selection of the selector lever for supplying the pressurized oil to the frictional engaging element bypassing the solenoid valve when the shift lever selects another gear range (1) in case of solenoid valve failure, and an underdrive engage control valve (30, 96) placed between the frictional engaging element and the switching valve for regulating pressure of the pressurized oil to be supplied to the frictional engaging. element in response to the pressurized oil outputted from the solenoid valve.

Abstract: A system for discriminating operation state of a lockup clutch of a torque converter of a transmission of a vehicle, more particularly to a system for detection a lockup clutch failure. In the system, three discrimination areas are preestablished with respect to the throttle opening and vehicle speed and reference value are determined in response to a selected discrimination area. The converter slip ratio is compared with the data and when the ratio is out of a range determined by the data, the lockup clutch operation is discriminated to be not normal. At that time, however, when the area is in a weak-engaged region, the engaging force is forcibly increased and the discrimination is conducted once again, thereby making it possible to conduct failure detection in the slip-engaged region and enhancing detection accuracy.

Abstract: An apparatus including a slip control device for controlling an amount of slip of a lock-up clutch disposed between pump and turbine impellers in a power transmission system of a motor vehicle, such that an actual slip speed of the lock-up clutch coincides with a target slip speed, the apparatus comprising a hunting detecting device for determining the presence of a hunting defect if an amplitude of variation of the engine speed is larger than a predetermined first reference while an amplitude of variation of the turbine speed is not larger than a predetermined second reference.

Abstract: An electronically actuated park control system for an automatic transmission for a wheeled vehicle including a transmission range selection control assembly that sends to a powertrain control module a park signal, the module being adapted to deliver an output signal to a park controller circuit for actuating electric actuator motors which activate a mechanical transmission park mechanism, the motors having position feedback monitoring features as the transmission park mechanism is engaged or disengaged, the controller and the park controller circuit having inherent design redundancies as well as independent watchdog circuitry that ensure that transmission park release or park application responds precisely to transmission range selector requests by the driver.

Abstract: In machines such as hauling units having electro-hydraulic transmission controls, it is desirable to ensure that in the event of an electrical malfunction or power failure the transmission remains in the gear that it was in when the electrical malfunction occurred. In the subject invention, an independent latching system is provided in a transmission which in the event of an electrical malfunction automatically latches the transmission in the existing gear. This is accomplished by providing a master latch valve mechanism and a latching shuttle valve to act in cooperation with an electrically controlled proportional valve and a proportional valve that controls engagement of a plurality of hydraulically actuated clutches. When the transmission is operating normally, the master latch valve mechanism directs pressurized fluid from a source of pressurized fluid to urge the latching shuttle valve to an open position.

Abstract: In machines such as hauling units having electro-hydraulic transmission controls, it is desirable to ensure that in the event of an electrical malfunction or power failure the transmission remains in one of its gear ratios. In the subject invention, a dependent latching system is provided in a transmission which in the event of an electrical malfunction latches the transmission in the existing gear ratio or a gear ratio within at least two gears ratios. This is accomplished by providing a master latch valve mechanism, a logic valve arrangement, and a latching shuttle valve to act in cooperation with an electrically controlled proportional valve and a hydraulic proportional valve that controls engagement of a plurality of hydraulically actuated clutches. The master latch valve mechanism directs pressurized fluid from a source of pressurized fluid through the logic valve to urge the latching shuttle valve to an open position.

Abstract: A gearshift controlling system for controlling a vehicle automatic transmission. In the system, a first alternative throttle opening degree is predetermined in case of failure of a throttle position sensor, and a second alternative throttle opening is similarly determined such that a gear ratio can be determined based on the detected vehicle speed and the second alternative engine load in a gear ratio decreasing or increasing direction. Either of the first alternative throttle opening degree or the second alternative throttle opening is selected and the gear ratio to be shifted to is determined in accordance with the predetermined gearshift schedule based on the detected vehicle speed and the selected alternative engine load, to output the gearshift command, thereby preventing unexpected gearshift to occur.

Abstract: A hydraulic control system for an automatic transmission of an automotive vehicle is provided which has a fail-safe function of preventing unsafe operation of the automatic transmission if a failure occurs in any of solenoid valves which control engagement operations of frictional elements such as clutches and brakes of the transmission. The hydraulic control system includes a hydraulic pressure flow control unit which controls hydraulic pressure flow between at least one of the frictional elements and at least one of the solenoid valves to allow the hydraulic pressure to be supplied to a predetermined combination of the frictional elements to achieve the power transmission at one of given gear ratios. The hydraulic pressure flow control unit restricts the hydraulic pressure flow to an inoperative combination of the frictional elements which provides no power transmission. With these arrangements, the power transmission is established if any of the solenoid valves malfunctions to allow the vehicle to travel.

Abstract: A method of shifting in a manual mode of an electronically-controlled automatic transmission system includes the steps of determining whether a shift lever of a shift lever mechanism is presenting a position error when the shift lever is in a manual position, determining whether at least one switch on the shift lever mechanism is presenting an error if a shift lever position error is not determined, determining whether a temperature of an automatic transmission or engine coolant temperature exceeds a predetermined threshold if the at least one switch is not presenting an error, determining whether the manual position conditions have been met, determining whether an upshift or downshift of the automatic transmission is scheduled if the manual position conditions have been met, and executing either an upshift or a downshift of the automatic transmission based on the determined upshift or downshift being scheduled.

Abstract: A motor vehicle has an engine, an automatic transmission and a chassis. A control system for the motor vehicle includes a gear ratio change control system, an engine control system and a communications channel through which the gear ratio change control system and the engine control system communicate with one another. The gear ratio change control system has function units being dependent on data of the engine and the chassis and being integrated with the engine control system. A gear ratio change unit has function units being dependent on data of the transmission. The communications channel exchanges data required for controlling the transmission, between the engine control system and the gear ratio change unit. An emergency device switches-over the gear ratio change unit, upon a malfunction of the communications channel, to receive control signals from a device not communicating with it through the communications channel.

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 control apparatus for a belt-type continuously variable transmission that has a drive pulley, a driven pulley, a V-belt trained around the drive and driven pulleys, a drive cylinder for varying the pulley width of the drive pulley, and a driven cylinder for varying the pulley width the said driven pulley. A pressure regulator valve produces pulley control pressures supplied to the drive and driven cylinders and a shift valve distributes the pulley control pressures to the drive and driven cylinders for varying the widths of the drive and driven pulleys for speed ratio control. An electric shift control normally controls the shift valve by electric power supplied to solenoid valves but the electric shift control causes the pressures in both the drive cylinder and said driven cylinder to be equal when the electric power is lost.

Abstract: A shift control system of an automatic transmission for setting a predetermined gear stage by applying first frictional engagement means and releasing second frictional engagement means, comprising: a pressure regulating mechanism for regulating an oil pressure to be fed to or drained from the first frictional engagement means; a failure detector for detecting a failure of an apparatus to participate in the regulation and control of the oil pressure which is to be fed to or drained from at least one of the first and second frictional engagement means: and a gear stage inhibitor for inhibiting the setting of the predetermined gear stage if the failure is detected by the failure detector.

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: A failure detecting method and apparatus for an automatic transmission of a vehicle having a vehicle speed sensor mounted on said vehicle for sensing a vehicle speed and an inhibitor switch attached on said automatic transmission for detecting a gear shift range position, The method is carried out by judging whether the vehicle speed is larger than a predetermined value; checking whether a neutral range position is detected; detecting whether another gear shift range position is absent after a predetermined time has lapsed; and then controlling the automatic transmission as if the gear shift range position is in a drive range. This enables one to precisely detect a failure of the range signal line and to control the automatic transmission in an optimum condition under any driving conditions.

Abstract: A control system for control of a clutch interposed between a fluid transmission unit and a speed change unit in a vehicular automatic transmission. The control system includes a first R.P.M. detector for detecting clutch input side R.P.M. and a second R.P.M. detector for detecting clutch output side R.P.M. A stop state detector determines if the vehicle is at a standstill and a starting operation detector detects a starting operation by the driver.

Abstract: A fail-safe device for an automatic transmission system outputs a signal to control the transmission operation according to vehicle speed and engine rpm (revolution per minute) when normal transmission operation is not achieved because of a malfunction of input equipment or an automatic transmission controller. The device includes a vehicle driving sensor, a signal converter, a signal processor, and a signal-output member. The vehicle driving sensor outputs a corresponding signal by sensing both a vehicle speed and an engine rpm that are varied according to a vehicle driving state. The signal converter is connected with the vehicle driving sensor, and converts the signal from the vehicle driving sensor into the corresponding AC (alternating current) voltage by varying each pulse generating rate according to the vehicle speed and the engine rpm.

Abstract: Electronic and hydraulic control system of an automatic transmission for automotive vehicle and method for controlling hydraulic pressure whereby line hydraulic pressure can be compensated. A hydraulic pressure state within the electronic and hydraulic control system is precisely detected and the signal of this detected hydraulic pressure is transmitted to a transmission control unit such that the malfunction of the valves and the correct gear shifting stage can be determined. Since the hydraulic pressure state can be detected to be compensated by the control of the TCU, the shift quality can be improved.

Abstract: An apparatus including a slip control device for controlling an amount of slip of a lock-up clutch disposed between pump and turbine impellers in a power transmission system of a motor vehicle, a slip-parameter monitoring device for detecting the actual slip speed of the lock-up clutch or a control error between actual and target slip speeds of the lock-up clutch, a summing device for obtaining a sum of values of the actual slip speed or control error detected by the slip-parameter monitoring device for a predetermined period of time, and a defect detecting device for determining the presence or absence of a defect in slip control of the lock-up clutch by the slip control device, on the basis of the sum as compared with a predetermined reference.

Abstract: A gear shift control apparatus for use in an automatic transmission having a friction element operable on a hydraulic pressure applied thereto in an engaged and disengaged state. A shift change control is performed to change the hydraulic pressure in a manner to produce a shift change according to a predetermined shift schedule based on transmission input and output shaft speeds and engine load. A section is provided for calculating the gear ratio obtained in the automatic transmission based on the transmission input and output shaft speeds. When a change is effected to one of highest and lowest gears or when a change is effected from one of the highest and lowest gears, a transient hydraulic pressure control of changing the hydraulic pressure from the first level to the second level is performed to change the friction element state so as to effect a shift change when the calculated gear ratio reaches a reference gear ratio.

Abstract: An electronic engine control controls the selection and confirmation of automatically selectable gears in a manual/automatic transmission. Failure to disengage the engine from the transmission within a predetermined time period, failure to reach a predetermined synchronous engine RPM window within another predetermined time period and failure to confirm gear engagement within yet another predetermined time period are three automatic shift failure modes which may cause an automatic shift attempt to fail or be aborted. A fourth automatic shift failure may occur if the clutch pedal is depressed during an automatic shift attempt. If any of the foregoing automatic shift failure mechanisms is detected, an error recovery algorithm which forms a part of the present invention determines the easiest/safest transmission gear to command to prevent the driver from having to manually attempt to engage the transmission after a failed automatic shift attempt.

Abstract: A speed change control apparatus of an automatic transmission has a transmission control unit. When determining a fault of a power-on/off determining section on the basis of engine load information from an engine control unit, the transmission control unit controls an oil pressure controller by regarding an engine as being in a power-on state in upshifting and by regarding the engine as being in a power-off state in downshifting. As a result, in either of upshifting and downshifting, the moment when a disengagement-side friction element of the transmission begins to slip and the moment when an engagement-side friction element is engaged are made proper. This makes it possible to surely prevent undesired rise in the engine rotation during the speed change in upshifting and inability in speed change in downshifting, which are caused by a fault of the power-on/off determining section.

Abstract: A diagnostic system is provided for detecting a fault condition in a transmission having a plurality of rotating components, a plurality of clutches, and a transmission control. The diagnostic system includes speed sensors producing speed and direction signals representative of the rotational velocity of the rotating components, a processor for calculating the relative rotational speed between two or more clutches and for indicating a fault condition in response to the relative rotational speed and a period of time.

Abstract: A method and apparatus for use with an automotive vehicle having an automatic transmission operable with a working fluid. The automatic transmission is coupled to an engine through a torque converter operable in a lockup mode where a mechanical connection is completed between the engine and the automatic transmission in response to a lockup command signal. A degree to which the working fluid is degraded is detected while the torque converter is operating in response to the lockup command signal which is produced when the vehicle speed exceeds a reference value. When the detected degree exceeds a predetermined value, the reference vehicle speed value is increased.

Abstract: A method of diagnosing a lock-up mechanism for a torque converter in an automatic transmission of an automotive vehicle includes the steps of sensing vehicle speed and engine speed, calculating a vehicle speed to engine speed ratio based on the sensed vehicle speed and engine speed, knowing when the torque converter transitions between unlock and lock are initiated, determining whether the calculated ratio is greater than a predetermined threshold when the torque converter transitions between unlock and lock, and concluding that a failure of the lock-up mechanism has occurred if the calculated ratio is not greater than the predetermined threshold within a predetermined time since transition of the torque converter.

Abstract: Power transmissions incorporate gear ratios including a plurality of forward ratios, a neutral condition and at least one reverse ratio. The establishment of each ratio is controlled by selectively engageable hydraulically operated friction devices, such as clutches and brakes. The interchange between forward ratios is controlled by the interchange of at least one friction device. The control elements to accomplish the establishment and interchange of the ratios include a pressure source, shift valve, solenoid control valves and pressure control valves. The solenoid valves are electrically actuated and the hydraulic portion of the control includes elements that permit continued operation of the transmission in selected ratios in the event of electrical discontinuance.

Abstract: A system for detecting malfunction of a transmission of a vehicle, more particularly a system for detecting a failure of a shift lever position sensor for a vehicle automatic transmission is provided with two detection modes based on urban driving and open-road driving. The number of times that the vehicle speed goes up and down between prescribed upper and lower values separately defined for the two modes is counted, when the shift lever position signal is absent. Probable failure is judged when the number of times reaches eight in the first mode and sensor failure is confirmed when the number of times reaches three in the second mode. Shift lever position sensor failure can be reliably detected irrespective of whether the driving environment is urban or open-road.

Abstract: A self-propelled lawn mower and control system for same which prevents the lawn mower from operating at high engine speed while in reverse, while still allowing a wide range of throttle speeds while in forward drive mode. Normally-open switches are closed to ground the primary ignition circuit when the lawn mower is in reverse and above a throttle speed threshold.

Abstract: A sensor failure and erroneous signal detection system for use in automobiles equipped with cruise control. This system prevents cruise control from operating if certain predetermined conditions occur. Further, the system will determine if the cruise control signal has been erroneously generated and set up an error "flag". A failure is determined in the cruise control system if either one of the following conditions is present when a cruise control signal is generated: (1) the vehicle is traveling below a predetermined speed; (2) the brake switch is on; (2) the shift range is in "N", "R" or "P"; or (4) either (1), (2) or (3) continues for a predetermined period of time. Upon occurrence of (1), (2), (3), or (4), an error has been detected and the automatic transmission is instructed to return to normal operation.

Abstract: An apparatus and method of electronically controlling a manual/automatic transmission after a power reset is provided. Within a predetermined time period after a power reset, the current commanded transmission gear is held, or alternatively the highest of the electronically selectable gears is commanded, until an accurate determination of the vehicle speed can be made. If the vehicle speed is thereafter determined to be below a minimum vehicle speed value, the transmission is commanded to the neutral position, or alternatively, the lowest of the electronically selectable gears is commanded. If the vehicle speed is above the minimum vehicle speed value, or alternatively, above a maximum vehicle speed value, then the transmission is commanded to the highest of the electronically selectable gears. In either case, further electronic shifts are inhibited for a predetermined time period after recovery from the power reset is accomplished.

Abstract: An arrangement drives an automatic selector appliance of a change-speed gearbox of a motor vehicle into a position for emergency running in the event of a failure of an electronic control unit. A specified forward gear is selected, after the vehicle has come to rest, by manually moving a range selector valve into a P position and back into a D position.

Abstract: A method and system for detecting a failure of an automatic transmission for a vehicle employing a speed shift range switch operation signal from a speed shift range switch as one of the control signals to control the automatic transmission. The method is carried out by: detecting a speed shift range from the speed shift range switch; generating a start signal indicating a starting state of a starter for expediting a start of an engine for the vehicle; and automatically controlling the automatic transmission so as to maintain the speed shift range in the case where "P" or "N" range is not detected when the start signal is "ON".

Abstract: In case where an engine rotational detection signal from an ignition pulse generator is not appropriately detected even if an amount of induction air and a fuel injection amount are larger than predetermined values, an engine rotational signal failure is decided, and an automatic transmission is controlled in a state before the decision. Therefore, the automatic transmission control based on the engine rotational speed such as, for example, a speed shift control (ordinarily a shift control), a lockup control (ordinarily a lockup control, a smooth control), a line pressure control (ordinarily a line pressure control, a starting time control) can be appropriately controlled. Thus, the automatic transmission control can be executed based on the engine rotational speed.

Abstract: A control method/system for sensing deflection-type gear neutral signal (GNS) errors in an automated mechanical transmission system (10) is provided. A gear neutral sensor (76/76A) provides signals indicative of axial position in a remote shift shaft (56) from which the neutral and not-neutral positioning of associated jaw clutch members (144) is inferred. Deflections in the shift members, such as the shift yokes (50), may result in erroneous indications of a neutral condition, which is a deflection-type gear neutral signal error sensed by the control of the present invention.

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 position sensing apparatus (10) for detecting the manually selected operating mode of an automatic transmission (14) in a motor vehicle comprising a digital position sensor (20) for providing a digital position signal and an analog position sensor (22) for providing an analog position signal. The position sensing apparatus 10 may be used to advantage in a position selection and detection system which further includes a selector (12) for selecting one of a plurality of predetermined selectable positions and a decoder (18) responsive to both the digital position signal and the analog position signal for determining the selected position.

Abstract: A vehicular automatic transmission (AT) hydraulic controller has an integrated valve. The integrated valve has a cylindrical cam shaft including convex and concave parts on the outer periphery thereof, and the integrated valve is connected to a motor for automatic control and a connecting part which is interlocked with an external gearshift operated by a driver. Hydraulic control of the integrated valve can be performed in two different ways, i.e., automatic control and manual control, and even if automatic control malfunctions due to an error, manual control can maintain the control of the AT and avoid any inconvenience. The structure of this integrated valve provides a high degree of design freedom and can implement a wide variety of AT functions. Accordingly, a light, compact and reliable AT equipped with both an automatic control mechanism and a manual control mechanism can be provided.

Abstract: A control system/method for an automated transmission system including a splitter-type, semi-blocked mechanical transmission (12) is provided. The control provides a technique for sensing auxiliary section engagement faults or auxiliary section and main section engagement faults and for operation in a fault-tolerant mode upon sensing such faults. In one embodiment, auxiliary section (214) engagement faults are sensed when the main section (212) is confirmed as engaged in an appropriate ratio and the transmission is confirmed as engaged in a ratio (GR.sub.N) other than the target ratio (GR.sub.T). In another embodiment, engagement faults are sensed when one section is confirmed as properly engaged and the transmission does not achieve engagement in a target ratio after a preset period of time.