The interest of the vehicle producers in fulfillment emission legislations without adopting after treatment systems is driving to the use of non-conventional energy sources for modern engines.
A previous test campaign dealing with the use of blends of diesel and propane in a CI engine has pointed out the potential of this non-conventional fuel for diesel engines. The soft adaptation of the common rail injection system and the potential benefits, in terms of engine performances and pollutant emissions, encourage the use of propane-diesel blends if an optimization of the injection strategies is performed.
In this work, the performances of a propane-diesel mixture in a research diesel engine have been investigated. The injection strategies of Euro 5 calibration have been used as reference for the development of optimized strategies. The aim of the optimization process was to ensure the same engine power output and reduce the pollutant emissions. The analysis has been supported by optical diagnostics for the visualization of the in-cylinder processes.
The results showed that the use of propane-diesel blends can improve the engine performances with new injection strategies specifically defined. Moreover, the enhanced fuel evaporation due to the propane content could improve the mixing process and leads to reduced particulate matter emissions.