To make the transmission oil pressure low as long as possible in the range where does not cause the slip of a V-belt driven stepless transmission when there is an accelerator pedal operation during constant speed running.
The target driving force deviation ΔTd obtained by deducting Tdn from the target driving force Tdc for constant speed running is estimated to be before or after of an instant t2 when it falls up to the setting value of ΔTds, in case that the target driving force Tdn of an accelerator rises from t1 as illustrated by stepping on the accelerator pedal to t1 during cruise control. Driving force is rapidly increasing to t3 when Tdn corresponds with Tdc because final target driving force Tdo makes Tdc and Tdn selection high and it needs that the transmission oil pressure is raised not to cause the belt slip. When considering the response delay ▵t of oil pressure, the optimal instant to command the rise of transmission oil pressure is t2. Consequently, a low oil pressure permission flag FLAG is set to be 1 for ΔTd≥ΔTds (before t2) and made to be FLAG=0 at the instant t2 of ΔTd<ΔTds and gives the order of the transmission oil pressure rise and then completes the rise of the transmission oil pressure for the slip prevention just at t3.
COPYRIGHT: (C)2004,JPO
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Shiro Fujitani
Kosaku Sugimura