Effects of advanced injection timing and inducted gaseous fuel on performance, combustion and emission characteristics of a diesel engine operated in dual-fuel mode

The current study aims to investigate the effects of advanced injection timing combined with dual-fuel mode on the diesel engine's overall performance, emission, and combustion characteristics under various loading conditions. In this study, blends of waste oil methyl ester (WOME) at 10%, 20%, and 30% v/v concentration and diesel fuel were used as injected fuel, while biogas was the inducted gaseous fuel through the inlet manifold with a flow rate of 0.8 kg/h. Experimentations were carried out on a 4-stroke single-cylinder water-cooled diesel engine, in which engine speed, injection pressure, and compression ratio were fixed at 1500 rpm, 220 bar, and 17.5:1, respectively. Based on experimental data, dual-fuel mode of WOME20-biogas combined with advanced injection timing to 24 degrees bTDC depicted the most positive results. Indeed, the higher brake thermal efficiency (2.40%), lower exhaust gas temperature (15.77%), but increased brake-specific fuel consumption (3.12%) and brake-specific energy consumption (1.85%) compared to diesel fuel were found at the highest load. Furthermore, increasing trends of in-cylinder pressure (7.48%) and heat release rate (4.71%), but diminished ignition delay (6.96%) as opposed to diesel fuel at higher loads were also reported. For emission analysis, a significant reduction of unburnt hydrocarbon (44.5%), carbon monoxide (61.72%), oxide of nitrogen (64.13%), and smoke intensity (47.42%) was obtained in comparison to conventional diesel fuel. Generally, the test diesel engine working on dual-fuel mode of WOME20-biogas combined with advanced injection timing of 24 degrees bTDC would be helpful to enhance the overall efficiency and emission characteristics.

Automated summary

The study explores the use of waste oil methyl ester and biogas in a dual-fuel mode with advanced injection timing to improve diesel engine efficiency and emissions under high loads. The results show increased thermal efficiency and decreased emissions compared to traditional diesel fuel, highlighting the potential benefits of this approach.