Toyota Jidosha Kabushiki Kaisha

Koji Oshima

Hiromichi Kimura

Keisuke Ota

Eiji Fukushiro

Tomohiro Asami

Kazuyuki Watanabe

Hitoshi Matsunaga

Kazuaki Nakamura

Takahiro Kondo

Shun Minaki

Toshio Sugimura

Akira Murakami

Masaru Morise

Ayumu Sagawa

Hirofumi Onishi

Mitsuhiro Umeyama

Koji Hattori

Hisanori Nomoto

Tomoe Osada

Nobuyuki Nagashima

Masanori Ohtake

Hiroomi Toi

Ayuma Sagawa

When it is determined to perform nth to (n+1)th coast downshift during nth to (n+1)th power-off upshift, an ECU starts increasing control to increase the hydraulic pressure of an engage-side element A in a predetermined mode and maintains the hydraulic pressure of a release-side element B at a value at which the increasing control is started until a predetermined period of time elapses from when the start of the increasing control. When a turbine rotational speed does not increase even after the predetermined period of time has elapsed, as the turbine rotational speed decreases below a value lower by a predetermined value than a synchronous rotational speed in the (n+1)th gear, the ECU executes feedback control over the hydraulic pressure of the element B so that the turbine rotational speed becomes the value lower by the predetermined value than the synchronous rotational speed in the (n+1)th gear.

Control device and control method for automatic transmission

A control device for a vehicular automatic transmission which can realize a shifting with quickened response with suppressing a turbine blow-up during the shifting is provided. When a response in hydraulic pressure control by a hydraulic pressure control circuitfails to satisfy a preset predetermined determining criterion, a shifting response is prevented from improving, in comparison to a case where the determining criterion is satisfied. Under a relatively low response of the hydraulic pressure control by the hydraulic pressure control circuitdue to air mixture to working oil, a control to inhibit a high-response shifting or the like is performed, so that a turbine blow-up caused by a delayed response of hydraulic pressure can be prevented. Thus, the control device for the vehicular automatic transmission can be provided, which can realize the shifting with quickened response, with suppressing the turbine blow-up during the shifting.

Control device for vehicular automatic transmission

If the a rotational speed difference (Ne&#x2212;Nt) between an engine speed (Ne) and a turbine speed (Nt) when it is determined that a lock-up ON condition (OFF&#x2192;ON) is satisfied is large, the lock-up clutch is not engaged but torque reduction control is executed to reduce the engine speed (Ne), thus reducing the rotational speed difference (Ne&#x2212;Nt) (steps STand ST). Then, once the rotational speed difference (Ne&#x2212;Nt) has been reduced to the target rotational speed difference (Nslp), the lock-up clutch is engaged (steps STand ST). In this manner, excessive heating of the friction material of the lock-up clutch is suppressed which increases the longevity of the friction material.

Control device and control method for lockup clutch and engine torque in a vehicle

When a post-direct shift gear position does not match a target gear position during a direct shift but before engagement of an input clutch for the post-direct shift gear position begins, an ECU executes engagement control on a reaction brake for the new target gear position instead of executing engagement control on a reaction brake for the post-direct shift gear position, and executes engagement control on an input clutch for the new target gear position instead of executing engagement control on an input clutch for the post-direct shift gear position.

Control apparatus and control method for automatic transmission

An ECU executes a program including the steps of: starting monitoring the turbine revolution speed and the output shaft revolution speed when a direct shift is started (YES in S) (S); performing complete disengagement control on a disengagement element () (S), lowering control pressure of a disengagement element () to preliminarily fixed control pressure (S); starting engagement control on an engagement element () when a set time period Is () passes (YES in S) (S); performing complete disengagement control on the disengagement element () when a set time period Is () passes (YES in S) (S); and starting the engagement control on an engagement element () when turbine revolution speed NT is equal to or larger than (the synchronous revolution speed of a gear after a shift&#x2014;a set value Ns) (YES in. S) (S).

An ECU executes a program including the steps of: starting monitoring the turbine revolution speed and the output shaft revolution speed when a direct shift is started; performing complete disengagement control on a disengagement element; lowering control pressure of a disengagement element to preliminarily fixed control pressure; starting engagement control on an engagement element when a set time period Ts passes; performing complete disengagement control on the disengagement element when a set time period Ts passes; and starting the engagement control on an engagement element when turbine revolution speed NT is equal to or larger than (the synchronous revolution speed of a gear after a shift&#x2014;a set value Ns).

An ECU executes a program including: a step of detecting a turbine revolution speed, a step of detecting an engine torque TE, a step of detecting a speed change ratio, a step of setting a range an enlarged slip region when a slip region enlargement condition is satisfied, and a step of enlarging the slip region toward a lock-up region side (high-load side).

Automatic gear control device

An ECU executes a program including causing a brake to enter an engaged state, when a first gear is implemented and when a difference between an output shaft rotation speed estimated from an input shaft rotation speed and a detected output shaft rotation speed is greater than a threshold value. When the brake enters the engaged state, the relative rotation between the inner race and the outer race of a one-way clutch is limited.

Control apparatus for automatic transmission

An ECU executes a program including detecting an engine speed; detecting a turbine speed; calculating a slip revolution speed of a torque converter as; calculating a hydraulic pressure control value based on the slip revolution speed and a map; and outputting a hydraulic pressure control signal to a linear solenoid. The map is set such that the hydraulic pressure control value is smaller as the slip revolution speed increases in positive values.

Control device for automatic transmission

A control apparatus for an automatic transmission including a gear-type transmission mechanism connected to an output shaft of a motive power source, the gear-type transmission including plural frictional engagement elements. The control apparatus senses a power-on downshift in which the frictional engagement elements are engaged during a downshift in a driving state of the motive power source, controls the motive power source so that in the power-on downshift an output of the motive power source is reduced, counts a time during which an input rotational speed of the transmission mechanism approximates an after-shift synchronous rotational speed, and controls the motive power source so that, if the time exceeds a predetermined time while the output of the motive power source is reduced, recovery from the reduction of the output of the motive power source is attained.

'Threshold A is substituted in a power-on state, 'threshold B', which is lower than &#x201c;threshold A', is substituted in a power-off state, and &#x201c;threshold C&#x201d;, which is lower than &#x201c;threshold B&#x201d; is substituted during a brake operation, as a rapid deceleration determination threshold. The rotational speed of an output shaft of an automatic transmission and the rapid deceleration determination threshold are compared to determine whether a vehicle is rapidly decelerating. The engagement state of a lock-up clutch is controlled based on whether the vehicle is rapidly decelerating.

An ECU executes a program including the steps of: starting disengagement of a Cclutch and a Bbrake when downshifting a transmission implementing gears in accordance with combinations of engaged clutches and brakes from sixth gear to third gear, or disengagement of the Cclutch and a Bbrake when downshifting from fifth gear to second gear; when at least one of the Cclutch and the Bbrake, or at least one of the Cclutch and the Bbrake, is completely disengaged, starting engagement of a Cclutch and the Bbrake when downshifting from sixth gear to third gear, or engagement of the Cclutch and the Bbrake when downshifting from fifth gear to second gear.

In a shift control system of an automatic transmission for a vehicle, an engaging torque applied to a predetermined friction element that has been engaged to establish a predetermined gear stage of the automatic transmission during running of the vehicle is gradually decreased to generate a slip in the predetermined friction element. Based on the engagigng torque of the friction element and a command value output to generate the engaging torque to the friction element, a predetermined relationship used for determining the command value for generating a required engaging torque is corrected. Learning quality or accuracy with respect to the predetermined relationship between the engaging torque of the friction element and the control value for generating the engaging torque may be sufficiently ensured.

Shift control system of automatic transmission for vehicle and shift control method thereof

In a control apparatus for a vehicle, when a coast downshifting is performed in response to a downshifting command from a vehicle operator during braking operation under the fuel cut control, the braking force of the wheel brake is increased so as to increase the deceleration. This makes it possible to achieve a predetermined deceleration with a good response to the deceleration request of the vehicle operator represented by the downshifting command. The control apparatus is structured to decrease the braking force of the wheel brake such that the increase in the engine braking force is offset by the inertia caused by the rise in the engine speed resulting from downshifting upon the coast downshifting due to the vehicle speed increase. The control apparatus for the vehicle, thus, reduces the shock caused by the sharp increase in the engine braking force.

Control apparatus and control method for vehicle

A hydraulic control system for an automatic transmission, which has a frictional engagement unit adapted to be kept in a slipping state when in a predetermined speed changing state and in an applied state when in another gear ratio changing state; and a drain oil establishing member for establishing a drain oil when the frictional engagement unit is kept in the slipping state comprises a drain pressure switching mechanism for supplying the drain oil to the frictional face of the frictional engagement unit when the frictional engagement unit is kept in the slipping state.

Growing community of inventors

Nagoya, Japan

Koji Oshima