Abstract: In order to control shifting of the transmission of a vehicle, from the viewpoint of obtaining the optimum fuel economy and/or power output performance, a transmission shift control device is proposed which comprises a throttle sensor which generates a throttle signal, an engine speed sensor which generates an engine speed signal, a shift position sensor which generates a shift position signal indicating the present operating gear of the transmission, a memory which stores a relationship between the throttle opening and the engine speed for each shift position or operating gear of the transmission to give a target value for one of these two signals in accordance with the other of them, and a comparator which receives one of the above two signals and compares it with the target value therefor given from the memory and generates either an upshift signal or a downshift signal which is indicated to the driver or sent to the transmission so as automatically to shift it.

Abstract: A method is disclosed for automatically shifting the sub-transmission of a vehicle which is also equipped with a manual transmission operated by hand by the driver. When the driver shifts by hand to a certain gearing ratio, a vehicle operating parameter is detected, and, on the basis of this detected value, the procedure for shifting the sub-transmission is modified. Shift control of the sub-transmission is performed in accordance with this modified sub-transmission shift procedure, for a first time period, while the manual transmission remains in this gearing ratio, and subsequently for a second time period shift control of the sub-transmission is performed so as to maximize fuel economy, while the manual transmission remains in this gearing ratio.

Abstract: For generating a transmission shift control command in accordance with the operating conditions of a vehicle engine, from the point of view of improving fuel economy of the engine, a transmission shift control device has a throttle sensor which detects the throttle opening to produce a throttle signal, an engine speed sensor which detects the engine speed to produce an engine speed signal, a throttle comparator which compares the throttle signal with a reference signal, an engine speed comparator which compares the engine speed signal with a reference signal, and a switching circuit which generates an upshift command or a downshift command on the basis of signals from these comparators, these commands being sent to the transmission of the vehicle, or to a display visible to the driver.