Evaporation and Cold Start Behavior of Bio-Fuels in Non-Automotive Applications

Worldwide increasing energy consumption, decreasing energy resources and continuous restriction of emission legislation cause a rethinking in the development of internal combustion engines and fuels. Alternative renewable fuels, so called bio-fuels, have the potential to contribute to environmentally friendly propulsion systems. This study concentrates on the usage of alcohol fuels like ethanol, methanol and butanol in non-automotive high power engines, handheld power tools and garden equipment with the focus on mixture formation and cold start capability. Although bio-fuels have been investigated intensely for the use in automotive applications yet, the different propulsion systems and operation scenarios of nonautomotive applications raise the need for specific research. A zero dimensional vaporization model has been set up to calculate the connections between physical properties and mixture formation. This model is able to calculate the vaporization behavior of different mixtures based on the chemical composition and the single component properties of fuels. Calculation cases for different applications and boundary conditions have been taken into account to evaluate the influence of fuel properties on the vaporization potential. In order to validate the results of the calculations, experimental investigations of the vaporization behavior have been performed. These investigations were made by using a cold start procedure on different four stroke engines. The results of the simulation give information about the cold start behavior of different fuels and are necessary to understand the mechanisms of vaporization during the cold start process.