Gaseous Emissions and Combustion Efficiency Analysis of Hydrogen-Diesel Dual Fuel Engine under Fuel-Lean Condition

Exhaust gas emissions from diesel engine combustion using alternative fuel may change in their quantities that can affect exhaust gas after-treatment devices and environmental ambient. This study presents theoretical analysis of combustion generated emissions and efficiency of hydrogen-diesel duel fuel in fuel-lean condition. A chemical equilibrium method by minimizing Gibbs free energy is employed to estimate exhaust gas products from diesel and hydrogen-diesel mode combustion. The combustion products, e.g., unburned hydrocarbons (CH₄), hydrogen (H₂), carbon dioxide (CO₂), carbon monoxide (CO) are comparatively investigated, based upon similar specific energy input. Subsequently, the obtained combustible products (CH₄, H₂ and CO) are used to calculate combustion efficiency, based upon chemical energy left in waste exhaust gases. The main findings are associated with the reduction in CO₂ corresponding to the increase in combustion efficiency in hydrogen-diesel combustion mode, depending on relative air-to-fuel ratios. Meanwhile, the CH₄, H₂ and CO contents in the flue gas increase in the operating conditions used.