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This paper deals with the study of different design configurations for intake valves and valve seats on a current production cylinder head and their effect on airflow behavior and optimization, under steady flow condition. The analysis was performed trough a Design for Six-Sigma methodology (DFSS). The cases were simulated through computational fluid dynamics (CFD) software and a prototype considering the best configuration was built and tested at flow bench. Correlation between simulation and experimental data was performed in order to validate the results for current, as well as, for future studies. The goal is to determine how geometric design variations on intake valve profiles and valve seats affect airflow on the particular cylinder head.

The present work deals with the possibility of an alternative internal combustion spark ignition engine, operating in Otto's cycle, with any fuel and with compression ratio limited by rm, for example, which the levels of power, torque, specific fuel consumption, emissions and knocking are considered optimyzed and satisfactory, be operated in a compression ratio, rM, higher than rm, so that with an adequated set of spark ignition, combustion chamber shape and correct air fuel mixture, that levels prior obtained with rm may be reached or even exceeded. Therefore, it may obtain, at least, the same cycle's thermal efficiency with different compression ratios (rM > rm) without any detriment on the engine's performance and durability. With rM this is possible due to the mentioned set, function of the used fuel, generated thermo dynamic cycle different from that with rm, where the peaks of pressure and temperature are not higher.