Dimethyl ether fuelled genset engine development and optimisation of novel fuel injection equipment for improved performance and emissions

Alternative low-carbon fuels offer the best solution to reduce greenhouse gas emissions from the transport and decentralised power generation industry and comply with stringent emission legislations. Dimethyl Ether is gaining attention among researchers as an excellent replacement for mineral diesel in compression ignition engines. However, dimethyl ether’s lower lubricity and viscosity pose a challenge in its utilisation in conventional fuel injection equipment, which requires several modifications for dimethyl ether adaptation. In this study, customised fuel injection equipment was developed for a genset engine. After that, the start of injection timing was optimised to compensate for the delayed start of injection, which was advanced by 2 oCA at lower loads and 8 oCA at higher loads. The performance, combustion and emission characteristics of the dimethyl ether-fuelled genset engine were assessed at a constant speed of 1500 rpm at varying engine loads (No Load, 1.25, 2.5, 3.75, 5, 6.25 bar BMEP). Brake thermal efficiency was comparable to baseline diesel. A novel fuel injection equipment was used to compensate for the retarded start of injection timing of DME. Due to the enhanced combustion efficiency, comparable brake thermal efficiency and lower tailpipe emissions were observed for DME and baseline diesel. Increased peak in-cylinder pressure indicated superior combustion at optimised start of injection timings for DME. Lower emissions of nitrogen oxides from dimethyl ether-fuelled engines were due to the higher latent heat of vaporisation and lower fuel ignition delay. Dimethyl ether has a higher cetane number and superior spray atomisation characteristics than baseline diesel, leading to superior fuel–air mixing, better combustion efficiency, and lower carbon monoxide emission. Soot was negligible from the dimethyl ether-fuelled engine due to the absence of C-C bonds in the fuel. This study demonstrated the bright potential of dimethyl ether for developing efficient and cleaner engines with extremely low regulated emissions, indicating its suitability for gensets.