Jatco Corporation

Nissan Motor Company Limited

Jatco Transtechnology Ltd.

Ikuo Hirose

Yoshifumi Fujita

Hideharu Sugiyama

Yuuji Saitou

Masato Tanaka

Koichi Hayasaki

Takashi Murasugi

Hirofumi Okahara

Kenichi Ooshima

Takashi Sano

A dual purpose pressure adjusting valve provides a hydraulic pressure upon failure of electric power supply and controls the hydraulic pressure selectively directed toward a high clutch and a low & reverse brake using a line pressure, that bypasses a manual valve, as a source pressure. A switching valve switches hydraulic pressure feeding passages of the high clutch and low & reverse brake in response to selection of a range position between D-range position and R-range position. A first rotation member and a transmission input shaft are connected to each other when the high clutch is engaged. The first rotation member is a member other than a transmission output gear. A high clutch inhibitor valve uses D-range pressure PD as a signal pressure and is arranged between the switching valve and the high clutch. The high clutch inhibitor valve opens a communication between the dual purpose pressure adjusting valve and the high clutch when the signal pressure is applied thereto and doses the communication between the dual purpose pressure adjusting valve and the high clutch when the signal pressure is not applied thereto.

Hydraulic control device of automatic transmission

A system for controlling a torque reduction at shifting for an automatic transmission is provided with actual gear-ratio detecting means for detecting an actual gear ratio out of input rotation and output rotation of the automatic transmission, and torque-reduction amount computing means for calculating a torque-reduction amount out of a torque-reduction set gain set previously, which is a rate of change of the torque-reduction amount with respect to a change in gear ratio, and the detected actual gear ratio. With this, the start and completion timings of torque-reduction control can be optimized to prevent elongation of shifting. This results in enhancement in the shift quality and in the endurance reliability of a friction material for shifting.

System for controlling torque reduction at shifting for automatic transmission

In a shift control system for an automatic transmission, shelf-pressure control means include means for increasing the engagement pressure of the friction elements at a first gradient as previously set after output of the shift command, wherein after output of the shift command and when start of the inertia phase is detected, a torque-reduction command is output to the torque-reduction control means, the engagement pressure at detection of the inertia phase is set as an initial shelf pressure to increase the shelf pressure at a second gradient set for each speed, and a torque variation part oil pressure is added only when detecting a variation in throttle opening, and wherein after start of the inertia phase and when completion of the inertia phase is detected, a torque-reduction completion command is output to the torque-reduction control means. With this, the shelf pressure can be set appropriately during inertia phase without needing an enormous data amount even if a variation in throttle opening is present.

Shift control system for automatic transmission

An automatic transmission, which has automatic shift ranges and manual setting ranges having a first speed gear position at which an engine brake is operable, is constructed in such a manner that a first friction element engaged at the first speed gear position and at a backward driving gear position is connected to a pressure regulating valve controlled by a timing solenoid valve. If a gear position is automatically shifted from a gear position at which the first friction element is unengaged to a gear position at which the first friction element is engaged, the timing solenoid valve is kept on for a predetermined time to delay the engagement of the first friction element to thereby prevent the shock from the shift. If the gear position is manually shifted from a gear position at which the first friction element is unengaged to a gear position at which the first friction element is engaged, the timing solenoid valve is immediately switched to an OFF state to quickly engage the first friction element and obtain the engine brake.

Control device of automatic transmission

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.

Automatic transmission learning control apparatus

An apparatus for controlling a lockup clutch provided in an automatic transmission having an impeller and a turbine. The pressure of the oil supplied to the lockup clutch is controlled by a lockup solenoid which is operable on a control signal having a variable duty cycle to operate the lockup clutch in a complete lockup mode to complete a mechanical connection between the turbine and the impeller and a released lockup mode to provide a hydrodynamic driving connection between the turbine and the impeller. In the presence of a command for a change of operation of the lockup clutch from its released lockup mode to its complete lockup mode, the initial value of the duty cycle of the control signal is set, based on at least one of conditions including the temperature of the oil, the engine load and the degree of slip permitted between the turbine and the impeller, at a value closer to the duty cycle set for the complete lockup mode of operation of the lockup clutch when the oil is in a condition causing a slow response to the duty cycle control.

Automatic transmission lockup clutch control apparatus

A hydraulic control device for an automatic transmission includes a reverse inhibit valve for inhibiting a reverse gear position to be established when the reverse range is selected by mistake. This reverse inhibit valve is placed in a selected one of a first state in which a first port communicates with a third port, and a second state in which a second port communicates with the third port, depending upon whether a solenoid pressure is applied to one end of a spool of the valve. If the reverse range is selected during forward running of a vehicle, the reverse inhibit valve is placed in the first state in which the first port communicates with the third port, so that an oil pressure of a friction element is drained through the first port.

Hydraulic control device for automatic transmission

In a hydraulic control device for an automatic transmission for obtaining the optimum shift-down timing by regulating an accumulator back pressure for an engaging element to be engaged in low-speed gear positions, switch control means is provided for communicating an output oil path communicating with an accumulator back pressure chamber, with a selected one of an accumulator control pressure oil path and a drain oil path. The switch control means maintains communication between the output oil path and the accumulator control pressure oil path due to the output feed-back pressure in the N-speed gear position, and brings the output oil path into communication with the drain oil path, using the N+1 pressure as the operating signal pressure, upon shifting-up from the N-speed to N+1-speed gear position. The switch control means also maintains communication between the output oil path and the drain oil path due to a force other than the N+1 pressure in the N+1-speed gear position, and brings the output oil path into communication with the accumulator control pressure oil path, using only the solenoid pressure as the operating signal pressure, upon shifting-down from the N+1-speed to N-speed gear position.

A gear shift control apparatus for use with an automatic transmission including a friction element operable on a hydraulic pressure applied thereto in an engaged and disengaged state. A gear ratio obtained in the automatic transmission is calculated based on transmission input and output shaft speeds. A reference gear ratio is set based on at least one of the transmission input and output shaft speeds. The hydraulic pressure is changed from a first level to a second level to change the friction element from the disengaged state to the engaged state so as to produce a change from a higher gear to a lower gear when the gear ratio reaches the reference gear ratio. The reference gear ratio increases as at least one of the transmission input and output shaft speeds increases. Alternatively, the reference gear ratio may be set at a smaller value as the rate of change of the gear ratio increases.

Gear shift control apparatus

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. The transient hydraulic pressure control is interrupted with inhibition of any change to the highest and/or lowest gear when at least one of the first sensor, the second sensor and the gear ratio calculated section is subject to failure.

A control valve arrangement for use in an automatic transmission has a recess defined by a lower portion of a transmission case. The recess has therein a mounting surface formed with outlet and inlet openings communicating with fluid passages formed in the transmission case. A center valve body is put on the mounting surface and has therein a hydraulic circuit. The center valve body has a first given portion formed with inlet and outlet openings mated with the transmission case outlet and inlet openings when the center valve body is properly put on the mounting surface. A lower valve body is put on a lower surface of the center valve body and has therein another hydraulic circuit. The lower valve body is constructed to have the same width as the center valve body so that the lower valve body has a second given portion located just below the first given portion of the center valve body. An upper valve body is tightly mounted on an upper surface of the center valve body and has therein yet another hydraulic circuit. A first separate plate is interposed between the center and lower valve bodies, and a second separate plate is interposed between the center and upper valve bodies. A bolt passes through the second given portion, the first separate plate, the first given portion, and the second separate plate, and is detachably connected to the mounting surface to tightly mount the valve unit to the mounting surface.

Control valve arrangement of automatic transmission

An automotive automatic transmission has a hydraulically operated clutch device and an electronic control unit. The clutch device includes drive and driven clutch plates and a piston for pressing the drive and driven clutch plates to establish an engagement therebetween when an oil chamber for the piston is fed with a certain amount of fluid. In order to control the clutch device, the following steps are employed, which are (a) issuing a first instruction signal to the clutch device; (b) feeding the oil chamber with the fluid by an amount which is sufficient for moving the piston from a rest position to a critical position which is ready for effecting the actual pressure against the drive and driven clutch plates; (c) issuing a second instruction signal to the clutch device; and (d) increasing the hydraulic pressure in the oil chamber to cause the piston to instantly establish the engagement between the drive and driven clutch plates.

Method and device for controlling clutch of automotive automatic

A hydraulic control system for an automatic transmission comprises a plurality of shift valves which connect a first hydraulic passage communicating with an N+2 speed apply chamber to a second hydraulic passage communicating with an N+1 speed release chamber upon N speed, where N is a whole number equal to or greater than 1.

Hydraulic control system for automatic transmission

In order to improve only a pressure variation characteristic of hydraulic fluid supplied to a hydraulically actuable frictional coupling, but also a pressure variation characteristic thereof discharged from the coupling, a pressure regulator valve is provided which has a signal pressure port connected via a fluid passage to a shift valve. An accumulator is connected to the fluid passage at a portion between one end and an opposite end of the fluid passage. The pressure regulator valve is operative to cause a change in hydraulic fluid pressure supplied to the coupling in response to a change in a signal pressure at the signal pressure port.

Hydraulic system for controlling engagement of frictional coupling in

A shift control system for an automatic power transmission, utilizes a logic for utilizing a shifting sequence for operating a plurality of shift solenoids for establishing valve operation in a plurality of shift valves in a predetermined order and for draining more than one speed servo pressure. The shifting sequence being a 4-2 downshift, whereby the shift solenoids are controlled such that the second speed gear ratio is shifted to via the first speed gear ratio.

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Shizuoka, Japan

Ikuo Hirose