Unveiling the Potential of Hydrogen in a Downsized Gasoline Direct Injection Engine- Performance and Emissions Experimental Study

The transportation sector’s growing focus on addressing environmental and sustainable energy concerns has led to pursuit of the decarbonisation path. In this context, hydrogen emerges as a promising zero-carbon fuel. The ability of hydrogen fuel to provide reliable performance while reducing environmental impact makes it crucial in the quest for net zero targets. This study compares gasoline and hydrogen combustion in a single-cylinder boosted Direct injection (DI) spark ignition engine under various operating conditions. Initially, the engine was run over a wide range of lambda values to determine the optimal operating point for hydrogen and demonstrate lean hydrogen combustion’s benefits over gasoline combustion.

Furthermore, a load sweep test was conducted at 2000 rpm, and the performance and emission results were compared between gasoline and optimised hydrogen combustion. An in-depth analysis was conducted by varying fuel injection time and pressure. This enabled us to explore the effects of these variables on the fuel’s performance and emissions, providing valuable insights for further optimisation.

The key findings of this study are significant. They note that hydrogen fuel allows the engine to operate under lean conditions with stable combustion up to 3.8 lambda. Lean combustion produces higher engine thermal efficiency, low cyclic variability, and near-zero NOx emissions. According to the study, hydrogen combustion produces zero emissions of hydrocarbons (HC), carbon monoxide (CO), and carbon dioxide (CO2) under a wide range of operating conditions, making it a clean and environmentally friendly fuel source. During low loading, exhaust hydrogen slip is less than 1000 ppm. This slip drops below 500 ppm as the load increases. Finally, the study proved that hydrogen is more stable than gasoline at a stoichiometric level. This suggests that hydrogen could replace gasoline in some applications, which has major implications for alternative energy.