Performance, emission and combustion characteristics of CI engine fuelled with diesel and hydrogen

Abstract

Hydrogen (H 2 ) is being considered as a primary automotive fuel and as a replacement for conventional fuels. Some of the desirable properties, like high flame velocity, high calorific value motivate us to use hydrogen fuel as a dual fuel mode in diesel engine. In this experiment, hydrogen was inducted in the inlet manifold with intake air. The experiments were conducted on a four stroke, single cylinder, water cooled, direct injection (DI), diesel engine at a speed of 1500 r/min. Hydrogen was stored in a high pressure cylinder and supplied to the inlet manifold through a water-and-air-based flame arrestor. A pressure regulator was used to reduce the cylinder pressure from 140 bar to 2 bar. The hydrogen was inducted with a volume flow rate of 4l pm, 6l pm and 8l pm, respectively by a digital volume flow meter. The engine performance, emission and combustion parameters were analyzed at various flow rates of hydrogen and compared with diesel fuel operation. The brake thermal efficiency (BTE) was increased and brake specific fuel consumption (BSFC) decreased for the hydrogen flow rate of 8l pm as compared to the diesel and lower volume flow rates of hydrogen. The hydrocarbon (HC) and carbon monoxide (CO) were decreased and the oxides of nitrogen (NO x ) increased for higher volume flow rates of hydrogen compared to diesel and lower volume flow rates of hydrogen. The heat release rate and cylinder pressure was increased for higher volume flow rates of hydrogen compared to diesel and lower volume flow rates of hydrogen.

Potential for Reducing Emissions in Reactivity-Controlled Compression Ignition Engines by Fueling Syngas and Diesel

“…The inhibition effect of the syngas on the diesel autoignition is enhanced by the increased H 2 fraction in the syngas, leading to the retarded ignition timing of the diesel fuel. However, the peak of the heat release rate is larger, and the combustion duration is shorter with the increased proportion of H 2 , which was also experimentally observed by Karagöz et al The wider flammability limit and the higher combustion rate of H 2 than CO is responsible for the faster heat release rate . Therefore, as soon as H 2 in the lean premixed charge is ignited by the diesel fuel, rapid combustion occurs.…”

“…However, the peak of the heat release rate is larger, and the combustion duration is shorter with the increased proportion of H 2 , which was also experimentally observed by Karagoz et al 49 The wider flammability limit and the higher combustion rate of H 2 than CO is responsible for the faster heat release rate. 50 Therefore, as soon as H 2 in the lean premixed charge is ignited by the diesel fuel, rapid combustion occurs. Furthermore, the higher H 2 fraction is helpful for the improvement of the combustion efficiency at the lean combustion mode, which can be observed from the considerably increased in-cylinder pressures in the expansion stroke in Figure 15.…”

Exploring the efficiency and emission characteristics of hydroxy-boosted canola biodiesel in comparison to traditional diesel fuels

“…In diesel engines powered by HHO, the combustion process is characterized by a significantly higher peak pressure, which leads to the formation of a notably slender flame reaction area and reduces the duration of combustion. This phenomenon compresses the gases that are burnt at the commencement of the combustion cycle to a temperature that is higher than what they achieve right after the combustion has occurred, consequently leading to the generation of NO x (Kumar et al, 2015). HHO gas addition increased the NO x values up to 49.80% compared to diesel fuel.…”

Review of Compression Ignition Engine Powered by Biogas and Hydrogen

“…The LHV to the H 2 (120 MJ/g) was higher than the diesel (42.5 MJ/g), contributing to increasing exhaust gas temperature (EGT) for diesel engine under DF mode [56]. Increase of H 2 energy share improved the combustion rate, which drived the reaction to complete, because the traffic air-fuel mixing process resulted in increased EGT [51,57] (Figure 11). The in-cylinder gas temperature decreased with the exhaust gas recirculation (EGR) because increased specific heating value of the air-fuel mixture reduced the O 2 concentration in the combustion chamber.…”

“…The local air-fuel mixture and in-cylinder temperature played a vital role in the CO emissions. Introduction of H 2 in intake main port under DF mode improved air-fuel mixture because H/C increase reduced emission-based carbon concentration [57]. Due to the reduction of carbon content in the fuel blend enriched by the H 2 , the CO, (CO 2 ) and HC in the combustion chamber dropped [64].…”