Aisin Aw Co., Ltd.

Shigetaka Wakisaka

Takayuki Kubo

Yoshihisa Yamamoto

Akira Isogai

Tomokazu Nomura

Yoshizo Akita

Munehiro Tashiro

Tsuyoshi Kawamoto

Kazufumi Ando

A system for control of the discharge pressure of an input clutch hydraulic servo at the time of a D&rarr;N shift, in which the peak value (DN_Omega_max) rate of change of the rotational speed of an input shaft increases if the initial value (DN sol Sweep Start SLT signal) of the pressure adjusting control becomes high or low. A convergence region (DN_Omega_limit_max) is provided. On the basis of comparison between the previous peak value (DN_Omega_max_ave1) and the present peak value (DN_Omega_max_ave2), and the direction of correction, the learning is performed in accordance with various maps in a direction toward the convergence region.

Hydraulic pressure control apparatus of automatic transmission

A downshift control determines whether a commanded downshift is a downshift oriented toward minimum shock or a downshift oriented toward responsiveness, based on inputs from various sensors. The oil pressure on the hydraulic servo which controls the releasing-side friction engagement element is controlled based on the determined downshift type (DT), so that the releasing-side friction engagement element is released in accordance with a selected one of a plurality of release patterns, i.e., release patterns corresponding to different downshift type indexes (Dt). The releasing speed of the releasing-side friction engagement element is changed in accordance with the downshift type. By properly determining the type of downshift, it becomes possible to realize a shift of a type in accordance with the driver's intention.

Speed shift control apparatus of automatic transmission

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Anjo, Japan

Shigetaka Wakisaka