Thermodynamic Loss Analysis of a High Power Motorcycle Engine with Focus on Alcohol Blended Fuels 2017-32-0070

The development of future internal combustion engines and fuels is influenced by decreasing energy resources, restriction of emission legislation and increasing environmental awareness of humanity itself. Alternative renewable fuels have, in dependency on their physical and chemical properties, on the production process and on the raw material, the potential to contribute a better well-to-wheel-CO₂-emission-balance in automotive and nonautomotive applications. The focus of this research is the usage of alcohol fuels, like ethanol and 2-butanol, in motorcycle high power engines. The different propulsion systems and operation scenarios of motorcycle applications in comparison to automobile applications raise the need for specific research in this area. In comparison to conventional gasoline physical and chemical properties of alcohol fuels are changing, which has a direct impact on mixture formation, combustion process, exhaust gas and exhaust gas after treatment of motorcycle applications. The combustion process is directly influenced by the mixture formation and the chemical composition of the liquid fuel and determines the boundary conditions for the exhaust gas after treatment. On this account, this study concentrates on the thermodynamic loss analysis of the combustion process of a motorcycle high power MPFI SI engine with special focus on different bio-fuel gasoline mixtures. The chemical fuel composition has a direct influence on the combustion process, wall heat transfer, scavenging losses and the enthalpy of the exhaust mass flow. The thermodynamic loss analysis provides a detailed quantification of different engine efficiency losses. The complex thermodynamic interactions cause a mutual influence of the individual losses. For this reason, the individual losses cannot be calculated separately and, thus, a defined calculation order is important. Based on the results of this thermodynamic loss analysis, the potentials of different bio-fuel gasoline blends can be shown. On this account the development of future flex fuel internal combustion engines should underline the needs of gasoline and bio-fuels.