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.
The article shows the methodology and calculation procedures based on Lagrange polynomial interpolation which were used to determine standard performance characteristics of the Polish production engine, type ANDORIA 4CTi90-1BE6. They allow to simplify the experimental research by maintaining a minimum number of measurement points and estimating the remaining data in an analytical way. The methods presented are convenient when it comes to the practical side because they eliminate the need for exploration of mathematical equations describing the various curves, which can be cumbersome and time consuming in the case of nonautomated accounts. The results of analysis were applied to actual experimental results, indicating sufficient accuracy of the resulting approximations. As a result, procedures may be used in bench testing of a similar profile, especially with repeated cycles of the experiment, such as optimization of operating parameters of combustion engines.