Mazda Motor Corporation

Mazada Motor Corporation

Kazuo Takemoto

Hiroshi Yoshimura

Takuji Fujiwara

Kozo Ishii

Fumiaki Baba

Keiji Bota

Tatsutoshi Mizobe

Shigeru Nagayama

Toshihiro Yamada

Koichiro Takeuchi

Kozo Ishi

Osamu Watanabe

A control system for a torque converter includes a lock-up clutch provided in the torque converter for connecting input and output members of the torque converter directly, and a shift valve having first and second spools disposed in series in a sleeve for shifting an introduction of an engaging and releasing pressure acting on the lock-up clutch in accordance with positions of the first and second spools. The first spool is subjected to a first hydraulic pressure at one end thereof. The second spool is subjected to a second hydraulic pressure at one end thereof opposite to the one end of the first spool. The first and second spools are subjected to a third hydraulic pressure therebetween. The control system further has a first control device for controlling the first hydraulic pressure, and an adjusting valve for controlling the releasing pressure of the lock-up clutch. The shift valve provides the first and second spools with first, second and third positions corresponding to a converter condition, lock-up condition and slip condition, respectively. The shift valve is shifted between the second and third positions when the releasing pressure is relatively low so that the releasing pressure is continuously changed irrespective of the shifting action among the first, second and third positions of the shift valve. An abrupt change in the engaging force of the lock-up clutch is prevented.

Control system for torque converter

A hydraulic pressure control system for an automatic transmission includes a multiple transmission gear mechanism having a plurality of gear stages and frictional elements for switching power transmitting paths in the transmission gear mechanism, a hydraulic control mechanism for controlling engagement and disengagement of the frictional elements to establish one of said gear stages, and a line pressure control device for controlling line pressure of the hydraulic control mechanism. A speed detecting device for detects a speed of an input element of the transmission gear mechanism during shift operation of the shift gear stage in the transmission gear mechanism, and a compensation device compensates the line pressure in accordance with signal from the speed detecting device. The line pressure is compensated by a learning control to reduce a torque shock due to the shift operation.

Line pressure control system for automatic transmission

A slip control system for a torque converter of an automatic transmission includes lock-up clutch device provided in a torque converter for connecting an input and output members of the torque converter directly. A torque detecting device detects a transmitted torque introduced into the output member of the torque converter, a speed difference setting device sets a target value of a rotation speed difference between the input and output members, a pressure difference control device controls a pressure difference between a releasing chamber and an engaging chamber of the lock-up clutch device, based on a predetermined relationship between the input torque and the speed difference so as to accomplish the target value of the speed difference, and a speed difference detecting device detects an actual speed difference between the input and output members. In a preferred embodiment of the invention, a compensatng device compensates the target value of the speed difference set by the speed difference setting device based on a deviation between the actual and target speed difference. A responsive slip control, therefore, can be accomplished.

Slip control system for torque converter of automatic transmission

An oil pressure control system for an automatic transmission employed in a vehicle comprises a device for producing line pressure, a device for supplying engaging friction elements in the automatic transmission with operating oil pressure obtained from the line pressure, a device for determining a pressure control variable based on operating condition of an engine with which the automatic transmission is coupled, a device for determining a supplemental control variable based on a duration of speed change or a state of speed change in the automatic transmission, a device for revising the supplemental control variable in accordance with the operating condition of the engine to produce a revised supplemental control variable, a device for revising the pressure control variable in accordance with the revised supplemental control variable to produce a revised pressure control variable, and a control device operative to control the line pressure in accordance with the revised pressure control variable when a specific speed change operation is performed in the automatic transmission.

Oil pressure control systems for automatic transmissions

A control system for a vehicle engine coupled with an automatic transmission, which comprises a detecting portion for detecting a condition of speed change operation in the automatic transmission, a speed sensor for detecting engine speed or turbine speed in the automatic transmission, a first period determining portion for determing a first period of time, in which the speed change operation is to be carried out, by calculation based on the speed detected by the speed sensor, a second period determining portion for determining a second period of time, in which the speed change operation is to be carried out, in accordance with a predetermined lapse of time after the condition of the speed change operation is selected, and a torque control portion operative to vary torque produced by the vehicle engine to suppress torque shock resulting from the speed change operation during the first period of time when a condition of shifting-up operation is detected by the detecting portion and to vary the torque so as to suppress torque shock resulting from the speed change operation during the second period of time when a condition of predetermined shifting-down operation is detected by the detecting portion.

Control systems for vehicle engines coupled with automatic transmissions

An automatic transmission has a transmission gear mechanism and a plurality of friction coupling members which are applied or released by hydraulic pressures applied thereto under the control of a hydraulic control system. The control system includes a hydraulic control circuit which controls the hydraulic pressure fed to or discharged from the respective friction coupling member, thereby changing the condition of application of the friction coupling members and causing the automatic transmission to shift. The plurality of friction coupling members includes first and second friction coupling members the conditions of application of which are changed during gear shifting from a first predetermined gear speed to a second predetermined gear speed. The first and second friction coupling members are fed with the hydraulic pressure respectively through first and second hydraulic passages. The hydraulic control circuit is provided with a pressure regulator valve which receives the pressure in the first hydraulic passage as a pilot pressure and regulates the hydraulic pressure to be fed to the second friction coupling member through the second hydraulic passage according to the pilot pressure.

Hydraulic control system for automatic transmission

A control system for a vehicle engine coupled with an automatic transmission, which comprises a controller operative to control a controllable subject, such as ignition timing, in the vehicle engine, in accordance with a controlled variable determined for the controllable subject, for varying an engine output of the vehicle engine in response to an operating condition of the vehicle engine and further for reducing the engine output so as to suppress torque shock resulting from a speed change operation carried out in the automatic transmission, a controlled variable setting device for determining the controlled variable in accordance with the operating condition of the vehicle engine and an operating condition of the automatic transmission, and a controlled variable revising device for varying the controlled variable so as to restrict variation in the controllable subject when the speed change operation is carried out in the automatic transmission under a condition in which the controllable subject is controlled to reduce the engine output in response to the operating condition of the vehicle engine.

A lockup torque converter of an automatic transmission for an automotive vehicle consists of an impeller connected to an engine, a turbine connected to the automatic transmission, and a lockup clutch disposed between first and second pressure chambers formed in a housing of said lockup torque converter for locking and releasing the lockup torque converter. A control unit supplies a hydraulic pressure into the first pressure chamber and withdraw a hydraulic pressure chamber from the second pressure chamber or reversely so as to actuate the lockup clutch to lock or unlock the lockup torque converter, respectively. A pressure regulating unit develops a pressure difference between the first and second pressure chambers when the shifting of the automatic transmission is detected, thereby causing the lockup clutch to allow the lockup torque converter to slip in accordance with certain conditions.

Slip control system for lockup torque converter

A control system for a torque converter includes a lock-up clutch provided in a torque converter for connecting an input member and an output member of the torque converter directly. An engaging and disengaging hydraulic device controls an engaging and disengaging action of the lock-up clutch. A shift valve provided with a first and second spools in series controls introduction of a driving hydraulic pressure into the hydraulic device. The first spool of the shift valve is subjected to a first hydraulic pressure at one end, while the second spool is subjected to a second hydraulic pressure at the other end. The first and second spools are subjected to a third hydraulic pressure therebetween. The control system further includes a first control device for controlling the first hydraulic pressure, a second control device for controlling the second hydraulic pressure, an adjusting valve for adjusting the driving hydraulic pressure introduced into the engaging or disengaging hydraulic device, and a third control device for controlling a hydraulic pressure for controlling the adjusting valve. Converter, lock-up and slip conditions of the torque converter can be selectively established by switching shift positions of the single shift valve.

Control system for torque converter of automatic transmission

An automatic transmission of a vehicle has a transmission gear mechanism having at least a lower gear-speed and a higher gear-speed, and first and second friction coupling members which are applied or released by hydraulic pressures applied thereto. The first friction coupling member is kept applied when the transmission is in the lower gear-speed and the second friction coupling member is kept applied when the transmission is in the higher gear-speed. A control system for the automatic transmission has a hydraulic control circuit which controls the hydraulic pressure applied to the respective friction coupling members, thereby changing the condition of application of the friction coupling members and causing the automatic transmission to shift, and a control unit which controls the hydraulic control circuit according to the running condition of the vehicle. The control unit normally makes lower the hydraulic pressure applied to the second friction coupling member when it is kept applied than that applied to the first friction coupling member when it is kept applied by a predetermined value. When the vehicle is starting with the transmission in the higher gear-speed, the control unit inhibits itself from making lower the hydraulic pressure applied to the second friction coupling member when it is kept applied than that applied to the first friction coupling member when it is kept applied.

A control system for a vehicle engine coupled with an automatic transmission, which comprises a torque controller operative to vary torque produced by the vehicle engine, in accordance with a controlled variable, so as to suppress torque shock resulting from a speed change operation carried out to vary a gear ratio in a power transmitting gear arrangement provided in the automatic transmission, an operation detector for detecting the speed change operation, a controlled variable setting device for determining the controlled variable in accordance with an operating condition of the vehicle engine and the speed change operation, and a controlled variable revising device for varying the controlled variable so as to reduce variation in the torque brought about by the torque controller under a condition in which the speed change operation causing a change from one to another of speed ranges of relatively small gear ratios is detected by the operation detector, as compared with variation in the torque brought about by the torque controller under a condition in which the speed change operation causing a change from one to another of speed ranges of relatively large gear ratios is detected by the operation detector.

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Hiroshima, Japan

Kazuo Takemoto