The paper presents methodology for calculating optimal drive torques which ensure reduced or minimal fuel consumption and emission of toxic components of exhaust gas during acceleration of a car. Data for fuel consumption and toxic emission in dynamic conditions (for a run with changeable speed) are obtained using experimental measurements during typical drive tests. A dynamic optimization problem for calculating a drive torque has been formulated using dynamic characteristics and a simple mat hematical model a vehicle when travelling in a straight line. The optimization problem has been solved for a drive with petrol and LPG. Results of numerical calculations followed by conclusions are presented.

The paper presents the simulation analysis determining the effect of tyre energy efficiency class on fuel consumption of a passenger car. Calculations were made assuming the wheel movement on a dry and smooth asphalt road surface. The tests based on a simulation model were performed on 61 types of tyres, being characterised by different sizes and energy efficiency classes. Different values of rolling resistance coefficient were adopted (in accordance with energy efficiency classes), also, the values of basic and additional resistance to motion were determined. Based on them, engine speeds and load torque corresponding to respective specific fuel consumption were estimated. This parameter allowed the relationship between average mileage fuel consumption and tyre energy efficiency class to be determined on the basis of the NEDC test.