Abstract
Keywords: continuously variable transmission, driveability, thrust force
One of the fundamental tasks undertaken by engineers in the branch of automobile construction has been the increase and optimization of history of driving force in wheels throughout the process of acceleration. An increase in the driving force of a car will promote safety on the roads and control of its course can improve the comfort of driving. However, the full optimization of driving force is not possible in the case of classical power transmission systems in which the leading role in controlling power transmission systems is taken by the human - driver. This situation is the case for classical power transmission systems with the manual system of transmission control. In this case the human constitutes the determinant of the parameters of power transmission system control, while the car construction engineers are only capable of optimizing the operation of such a system with a view to optimization of combustion engine operation under specified parameters. This optimization most commonly involves throttle opening, fuel injection intervals and ignition advance angle in such a way which ensures adequate conditions for the process of combusting air-fuel mixture. Simultaneously, the selection of transmission ratio is the role of the driver, which is conducted in a subjective way for the purpose of adapting vehicle speed to the instantaneous traffic conditions, thus imposing a specific rotational speed of the engine. This way of control is a long way apart from optimum. To improve of control process and achieving of vehicle driveability indicators an automatic selection of transmission ratio is necessary. In the manual transmission is tendency to increase number of gears, what make the selection of optimum gear difficult.