FIELD: transport.
SUBSTANCE: invention relates to automotive industry. To up the fuel use efficiency, shifting to lower gear at vehicle approach (C) to slope is forecast due to decrease in vehicle speed. Actions aimed at delaying or avoiding said shifting to lower gear are selected. Automatic speed maintenance system is controlled in compliance with selected actions. Maximum speed is decreased temporarily at shifting to lower gear by preset value to decreased maximum speed at shifting to lower gear (Vmax.low). Actions aimed at delaying or avoiding said shifting to lower gear are forecast. In case that shifting to lower gear is not possible, it is sufficient to decrease maximum speed at shifting to lower gear. Additionally, proceeding from current motion conditions, minimum speed (Vgrade) is defined for first position (B) whereat vehicle decelerates at climbing. Here, shifting to lower gearing can be delayed or avoided. Proceeding from current motion conditions, ACS is controlled to increase vehicle speed at approach to said first position (B) to said minimum speed when vehicle reached first position (B).
EFFECT: higher efficiency of fuel use.
8 cl, 10 dwg
