Analysis of Combustion Conditions for Sustainable Dual-Fuel Mixtures

The scientific contribution is focused on the analysis and optimization of combustion conditions concerning the dual-fuel mixtures. The greatest attention was paid to the temperature of intake air when a mixture of ethanol and gasoline created the applied fuel. An experimental fuel mixture was added into the intake pipe and ultra-low sulphur diesel fuel (ULSDF) was added directly into the engine cylinder using the CR (common rail) injection system. The article analysed the medium- and high-level operational engine load, whereby the engine timing parameters originally corresponded to a conventional diesel engine. The obtained results of the performed analysis showed that the temperature of intake air affected the following operational parameters: delay of ignition, pressure rise rate in the engine cylinder and the maximum level of pressure in the engine cylinder. Lower values of the intake air temperature enabled higher injection speeds for the ethanol–sustainable mixture (ESM), especially at high engine loads. An increase in the injection speed was possible due to lower charge air temperature. While there were reduced nitrogen oxide emissions, we also noted a reduction in both carbon monoxide emissions and the total amount of unburned hydrocarbon emissions.