Alvarenga, L., Vianna, M., Pierobom, M., and Andrade, R., "Friction and Pumping Losses Estimation in Flex Internal Combustion Engines with Variable Valve Actuation System Using Chamber Pressure Measurement," SAE Technical Paper 2012-36-0363, 2012, doi:10.4271/2012-36-0363.
Increasing competition in the automotive sector, according to new energy and environmental legislations, requires that the vehicles have higher performance with lower fuel consumption and pollutant emissions. These factors encourage the study of new technologies such as the Variable Valve Actuation System (VVA) in internal combustion engines. To accomplish this, a detailed study of friction and pumping losses present in the engine becomes relevant, as they directly influence its efficiency. According to Heywood , these losses vary in relation to the delivered energy from 10% at full load to 100% at idle, when there is no production of effective work. This paper proposes the application of combustion chamber pressure analysis to separately identify and measure the friction and pumping losses in engines with VVA.