Experimental Validation of Laminar Flame Model for CH4/Diesel Dual Fuel Engine applied to H2/Diesel Combustion

Despite of having high thermal efficiency and wide range of operation, compression ignition (CI) engineshave high exhaust emissions of particulate matter (PM) and nitrogen oxides (NOx) which are harmfulfor the environment. In order to keep up with the latest stringent regulations on emissions, CI engineshave been pushed to work with different fuels. In particular, the usage of gaseous fuels along with dieselfuel in dual fuel mode demonstrated to be a valid solution, especially for large bore applications. Indeed,a large part of the diesel liquid fuel is substituted with alternative gaseous fuels that is injected into theintake manifold to form a premixed charge with air, which significantly reduces PM and, in many cases,NOx. Even though, methane has been the mostly used gaseous fuel for dual fuel CI engine, the necessityto reduce CO2 emissions as well, has led hydrogen to be one of the most promising alternatives.Because of its faster burning velocity and wide range of air to fuel ratios, a different model for its combustionmust be used for predictive purposes. In current work, a dual-fuel combustion model has beenimplemented in GT-Power with the aim of simulating and investigating the characteristics of hydrogendieselcombustion. Initially, a dual fuel model with methane was used and experimentally validated. Alaminar flame speed model was built and incorporated in the software with the approaches of Heywoodand Gülder studies. Design of experiments and design optimizer were used to find the optimal valuesof the combustion model parameters matching in-cylinder pressure curves. Once the model was validatedwith methane, the same methodology has been adapted to use hydrogen instead. Two new correlationsare built and implemented in the code starting from literature experimental measurements. Thesimulated results of hydrogen-diesel combustion allow to foresee a burn rate consistent with methanedieselones.