| 摘要 |
PROBLEM TO BE SOLVED: To detect interlock on shifting with excellent responsiveness for an automatic transmission shifting by switching an engagement condition with a frictional engagement element for high-speed stage and a frictional engagement element for low-speed stage. SOLUTION: A second derivative valueΔΔNt of a turbine rotating speed Nt is calculated (S202). Frequency shaping is carried out to eliminate a high frequency component of the second derivative valueΔΔNt (S203). A lower limited value of the frequency-shaped second derivative valueΔΔNt after starting of shifting is calculated (S205). Then, a reference value is obtained by an expression; reference value = lower limited value -α(S206). When the second derivative valueΔΔNt is less than the reference value and rapid reduction change of the turbine rotating speed Nt is detected (S207), the generation of the interlock is determined (S208).
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