| 摘要 |
PROBLEM TO BE SOLVED: To determine a hydraulic fluid pressure instruction value for promoting the completion of a stroke of friction elements which are fastened at the time of shift in such a condition that no shock occurs upon initiation of fastening of the friction elements. SOLUTION: In order to set a hydraulic fluid pressure instruction value Pc for promoting the completion of a stroke of friction elements to be fastened, to an equivalent return spring pressure P4, this instruction value Pc is determined so as to be increased from zero to the equivalent spring pressure P4 during a period by which a preset standby phase timeΔTST elapses from a moment t1 of a stand-by phase shift instruction to a moment t2. In this case, increase of the hydraulic fluid pressureγfor the friction elements is started with a time delay determined by hardware, and thereafter, when it comes to the instruction value Pc, the instruction value Pc has a low value which has not yet come up to the equivalent return spring value P4, and accordingly, the hydraulic fluid pressure can come up to the hydraulic fluid pressure instruction value Pc with a level differenceΔPd which is smaller than a conventional hydraulic fluid pressure level differenceΔPd1, and thereafter, the instruction value Pc and the actual pressureγcome up to the equivalent spring pressure P4. Thus, a shock upon staring the fastening of the friction elements can be small.
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