To perform gear shift control according to a driving intension to a vehicle even if a vehicle speed sensor malfunctions, and to prevent a high-speed starting state or selection of a low-speed side gear shift ratio in spite of high-speed traveling.
Normally, a target drive step number of a shifting stepping motor is decided such that a target input rotation speed (a target gear shift ratio) found from a gear shift map on the basis of a throttle opening and a vehicle speed detected by the vehicle speed sensor is realized. When the vehicle speed sensor malfunctions, the driving intension to the vehicle is decided from an acceleration/deceleration decision based on an input rotation speed Ni, ON/OFF of a brake switch 5 and ON/OFF of an idle switch 6, on the basis of a map shown in Figure, it is decided whether the driving intension is an upshift (UP) request, a downshift (DOWN) request or a gear shift ratio hold (HOLD) request, and a gear shift is advanced such that the driving intension is accomplished with sequentially correcting the target gear shift ratio to the request direction. Thereby, the gear shift control coinciding with the driving intension is executed to prevent the high-speed starting state or the selection of the low- speed side gear shift ratio in the high-speed traveling.
SHIMANAKA SHIGEKI
TAKIZAWA SATORU
AKANUMA MASATOSHI
SUZUKI TAKAYUKI
