Vehicle transmission shift control apparatus

In a vehicle which is driven by an engine via a transmission, a transmission shift control device for minimizing the brake specific fuel consumption of the vehicle, said device comprising:

• a throttle sensor which detects the value which represents the throttle opening of the engine and generates a throttle signal;
• an engine speed sensor which detects a value which represents the engine rotational speed and generates an engine speed signal;
• a throttle comparator which receives at least one reference signal which it compares with the throttle signal which it receives from said throttle sensor and generates a signal resulting from the comparison;
• an engine speed comparator which receives a reference signal and compares it with the engine speed signal which it receives from said engine speed sensor and generates a signal as a result of the comparison;
• and
• a switching circuit means which generates either an upshift command or a downshift command and sends it to the transmission on the basis of said signals fed to it from said throttle and engine speed comparators, said upshift command being generated when said brake specific fuel consumption of said vehicle is lowered by said engine speed being reduced while maintaining the engine output power constant, and said downshift command being generated when said brake specific fuel consumption is lowered by said engine speed being increased while maintaining the engine output power constant.