Fuel-derived Methane Emission Characteristics of Spark-ignition Engines

Abstract

In recent years, Spark-Ignition engines with direct injection (DI) have become mainstream in response to tighter automotive emission regulations and the need to become carbon neutral. The gas temperature is low during cold start, so reducing methane emissions which has lower catalyst purification rate at low temperature is effective. In this study, the methane emission characteristics related to three fuels with different characteristics were analyzed using chemical reaction simulations and actual engine tests. The results of computational simulation showed that the balance of reaction acceleration and reaction freezing affected the amount of methane emission related to methyl radical. In the actual engine test, physical properties of the fuel types also affected the amount of methane emission.