Pel'o R. Increase of vehicle’s fuel efficiency by formation of rational laws and algorithms of transmission gear-shift

The presented dissertation analyzes and estimates the selection of shift points in a stepped mechanic transmission of a vehicle in acceleration and deceleration operating mode under the conditions of fuel efficiency. It presents a comprehensive study of theoretical grounds of gear shift processes organization with the help of clutches under the conditions of continuous power flow transmission (with the closed clutch) and a simultaneous automatic correction of speed and loading modes of the operation of an internal combustion engine. In particular, it has been thoroughly elaborated four possible algorithms of automatic correction of engine operating modes when the driving mode predetermined by the driver is maintained: stabilization of the engine shaft angular velocity (ω – control); transitional mode of engine operation according to the line of minimal fuel loss in the function of engine power (g – control); dynamic transitional mode with short-term shifts to external traction and braking characteristics (the so called forced modes N – control); stabilization of engine turning moment (М – control). The conducted analytical researches proved the lowest indices: the loss of fuel, the deviations from the operating mode determined by the driver and the work of friction clutch skidding (energy losses) during the gear shift in a traction mode (acceleration) occurring just when the work of the engine operation is automatically controlled according to the algorithm of N – control. The application of dynamic transitional mode of engine operation also has an advantage over the other modes of driving (reverse shifts) when the vehicle decelerates. At the same time it should be noted that the possibilities to realize the forced modes of engine operation adjustment proper in the extreme zones of (minimal or maximal) velocity of engine shaft revolution, with the only realizable algorithm М – control (unforced modes of engine operation correction) are limited. The obtained results are rather generalized, however considerable simplifications have been introduced into the model of the automobile. In particular, the schematically considered very simple gear case in fact completely represents the principles of operations pertain to mechanical stepped transmission of any design.