Experimental Study of Hydrogen Addition on Waste Cooking Oil Biodiesel-Diesel-Butanol Fuel Blends in a DI Diesel Engine

In this study, the effects of hydrogen addition on diesel-biodiesel-butanol fuel blends were investigated in terms of engine performance, combustion, and emission characteristics under different engine operating conditions. The experiments were performed with eight different fuel blends at a constant engine speed of 2000 rpm, which is the maximum torque value of all test fuels. The four operating conditions were at 25%, 50%, 75%, and 100% engine loads. Hydrogen was delivered to diesel-biodiesel-butanol fuel blends through the intake manifold with different rates of fuel mass consumption. The experiment results were compared with euro diesel and absence of hydrogen addition for all test fuels. The experimental results have revealed that at 2000 rpm engine speed, the brake torque, in-cylinder pressure, and exhaust gas temperature increased with the addition of hydrogen. Nevertheless, the brake-specific fuel consumption, carbon monoxide (CO), carbon dioxide (CO2), hydrocarbon (HC), nitrogen oxides (NOx), and smoke opacity emissions decreased under various engine conditions. The heat release rate was generally shown to be decreased with higher engine loads and increased with lower engine load conditions, while a rise in thermal efficiency was observed. Therefore, the addition of hydrogen in a diesel engine usually exhibited fewer emissions, improved the combustion process, and increased the brake torques of the engine by comparison to the absence of hydrogen addition.