Hydrogen Induction in a Dual-Fuel Mode Common Rail Direct Injection Compression Ignition Engine Running on Ethanol–Diesel Blends: Combustion, Performance, and Emission Characteristics

This study investigates the simultaneous incorporation of ethanol and hydrogen (H₂) as a potential alternative to conventional diesel in a common rail direct injection compression ignition engine. Ethanol was blended with diesel in varying proportions (10–40%) and investigated at three H₂ flowrates (5, 10, and 15 LPM). The results reveal a complex interplay between combustion characteristics, performance, and emissions. Increasing ethanol content reduced peak cylinder pressure and net heat release rate across all H₂ flowrates, while higher H₂ flowrates improved these metrics for specific blends. The brake thermal efficiency (BTE) improved with increasing H₂ flowrates. Additionally, brake-specific fuel consumption (BSFC), carbon monoxide (CO), unburnt hydrocarbon (HC), and smoke emissions decreased with the addition of H₂. However, at a specific H₂ rate, these parameters increased with higher ethanol percentages, while nitrogen oxide (NO_x) emissions followed an opposite trend. Overall, substituting 30% diesel with ethanol and incorporating 15 lpm H₂ (D70E30 + 15 LPM H₂) resulted in higher BTE and reduced BSFC, CO, HC, smoke emissions, and NO_x emissions comparable to that of neat diesel.