Análise do processo de trocas gasosas em um motor de dois cilindros sobrealimentado com restrição da entrada de ar

Abstract

An analysis of the gas exchange process of a four-stroke spark ignition engine is presented in this study. A yamaha R3 engine was modified in order to operate with a RHB 31 IHI turbocharger and with an intake air restrictor. This engine was installed in a prototype vehicle, which was designed for the Formula SAE student competition, and performance tests were conducted on a chassis dynamometer. By comparing experimental performance data of the vehicle equiped with turbocharged and naturally aspirated engine it was found that the gain in brake power reached 69% at its peak value. Additionally, using the 1D gas-dynamics simulator Ricardo WAVEm four virtual models of the engine were built considering turbocharged and naturally aspirated operation, with and without the intake air restrictor. These virtual models enable predicting the response of the engine to any conditions imposed to it, thus allowing conducting optimization studies. The validation of the models was made by comparing their predictions with experimental data obtained from chassis dynamometer tests. Based on such comparisons it was possible to suggest some changes to the admission system as well as in the operating conditions. After analysing possible improvements to engine components, it was obtained an additional 3 – 5% performance gain.