Aisin Aw Co., Ltd.

Toyota Jidosha Kabushiki Kaisha

Masao Saito

Nobuaki Miki

Hiroshi Tsutsui

Masaaki Nishida

Yoshihisa Yamamoto

Masayuki Sugiura

Takeshi Nasu

Kiyohiko Sugiura

Kazumasa Tsukamoto

Kenji Suzuki

Yasuo Hojo

Hideaki Otsubo

Takeya Oka

Masaharu Chiba

Kunihiro Iwatsuki

Kazunori Ishikawa

Takao Taniguchi

Masanari Sakae

Akitomo Suzuki

Yoshikazu Sakaguchi

Muneo Kusafuka

Takayuki Kubo

Takashi Hagino

Hideyuki Numata

Masamichi Unoki

Junichi Nishimura

Yutaka Taga

Hiromichi Kimura

Norimi Asahara

Issei Otsubo

Keisuke Sakamoto

Masatoshi Taguchi

Tadao Otsuki

Masayuki Kuwata

Hirotaka Hayakawa

Kunhiro Iwatsuki

Front grille for an automobile

Motor vehicle and/or toy replica thereof

Automobile

A learning controller makes learning correction based on a time t,between start of a shift control routine and detection of start of a change in rotational speed of the transmission input shaft and further based on the amount of rotational speed change &ohgr;,&prime; at the detected start of the rotational speed change. When the time t,is longer than a basic time and when the rotational change amount &ohgr;,&prime; is too large, it is determined that a servo piston has not been sufficiently advanced and the shift control is corrected so that the time t,is lengthened. When the time t,to the detected start of the rotational speed change &ohgr;,&prime; is too small, it is determined that, while the piston has been advanced properly, the target engagement pressure P,in torque phase control is too low because of a miscalculation, and the shift control is corrected so that the target engagement pressure is raised.

Hydraulic control system for automatic transmission

In an electronic control system for an automatic transmission, a vehicular input signal detecting system samples an analog signal from the sensor based on a pulse signal output to control a solenoid.

Vehicular input signal detecting system

In a disengagement side control, in a power on state, a disengagement side pressure P.sub.W is output, P.sub.W being set higher than a base pressure dependent on input torque, and a disengagement side frictional engagement element is engaged and maintained. In a power off state, a disengagement side pressure lower than the base pressure is output, and the disengagement side frictional engagement element slips. In the disengagement side control, when the vehicle driving state is changed from the power off state to the power on state, the disengagement side pressure P.sub.W is changed from that for a slip state to that for a maintain state.

When a shift to a second gear ratio (second ratio) is determined during a shift control for a first shift (shift from fourth ratio to third ratio), the process status, or circumstances, of the first shift is determined using a hydraulic pressure for a fourth brake being engaged at the determination. When the process status, that is, the process circumstances, is in early phase, the first shift is interrupted and shift control for the direct shift to the second ratio (shift from fourth ratio to second ratio) is performed (first shift pattern). When the process status is in a late phase, the first shift control is continued, and after ending of the first shift control, the control for the shift to the second gear ratio (shift from third ratio to second ratio) is performed (second shift pattern). In the case of power off state, the second shift pattern is performed irrespective of the process status.

Shift control device for automatic transmission

When a vehicle driving state of an automatic transmission is changed to a power-off state from a power-on state during a down shift involving the disengagement of one friction element and the engagement of another friction element, a disengagement side pressure PA is reduced rapidly by a feedback control based on the change in gear ratio because of a reduction of an input torque. The disengagement side pressure control is unable to complete change of the gear ratio to complete the down shift. When the disengagement side pressure is reduced to a value less than a return spring load pressure PG or when the gear ratio change has not achieved a basic value in a predetermined time, the down shift control is changed from primary control by the disengagement side pressure control to primary control by an engagement side control so that the gear ratio change is completed by control of the engagement side pressure.

A hydraulic control unit of an automatic transmission calculates deceleration during a coasting downshift, and calculates a piston play offsetting time, that is, the lag time that elapses between a shift decision and the start of the shift, on the basis of a correction value determined in accordance with the lag time learned from the previous shift. Based on the rate of deceleration and the piston play offsetting time, the downshift line in the speed shift map is corrected, that is, advanced in timing. Using this timing-advanced shift line, the control unit makes an earlier shift decision such that the shift starts in a proper state of operation, thus reducing shift shock during a coasting downshift and preventing excessive engine speed during a high-speed upshift.

Hydraulic control apparatus of automatic transmission

Growing community of inventors

Nishio, Japan

Masao Saito