| 摘要 |
PROBLEM TO BE SOLVED: To stably optimize shift proceeding speed at the beginning of inertia phase depending on rotational difference between rotation of a turbine before the gear shift and that of after the gear shift in drive down shift without feedback control, by providing a hydraulic control means on releasing side. SOLUTION: In hydraulic control on releasing side of drive down shift, control is carried out to processed with gear shift at the beginning of inertia phase whole keeping oil pressure which is obtained by subtracting control requirement differential pressure PR3 from oil pressure at a time of starting inertia phase. Thereby, without feedback control which giving rise to a problem of unstable control caused by request for high detection accuracy or delay of response, proceeding speed of gear shift at the beginning of the inertia phase is stably optimized depending on rotational difference NTDIF between rotation of a turbine before the gear shift and that of after the gear shift. That is, at a low speed where the rotational difference NTDIF of the turbine is small, there is prevented idling of an engine caused by missing preparation for start-up of the oil pressure on the releasing side. At high speed where the rotational difference NTDIF is large, the rotation of the turbine can be blown up.
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