The authors developed the kinematic scheme of electromechanical transmission and designed its power block for the military track laying vehicle weighing 54 t and with a maximum speed of 75 km/h; they defined rational values of kinematic and power parameters and characteristics of the transmission and the hybrid power plant; power of the heat engine, generator, power electric motors and electrical drives energy. This paper presents external fuel and power characteristics of a heat engine with coordinates of the minimum specific fuel consumption, when the option of controlling the heat engine which provides minimum fuel consumption at the vehicle movement on the test route is chosen.