Effects of Injection Timing on Combustion and Emission Performance of Dual-Fuel Diesel Engine under Low to Medium Load Conditions

• Published in: Energies (Basel) Vol. 12; no. 12; p. 2349
• Main Authors: Zhou, Hua, Zhao, Hong-Wei, Huang, Yu-Peng, Wei, Jian-Hui, Peng, Yu-Hui
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 19.06.2019
• Subjects: Air pollution; Air temperature; bench test; Biodiesel fuels; Carbon dioxide; Combustion; Combustion chambers; Design of experiments; Diesel; Diesel engines; Diesel fuels; Dual fuel; dual-fuel engine; Emissions; Energy efficiency; Engines; excess air ratio; Flammability; Gases; injection timing; Load; Natural gas; Nitrogen oxides; Optimization; Pollutants; Retrofitting; Soot; substitution rate; Beijing China; China
• ISSN: 1996-1073; 1996-1073
• DOI: 10.3390/en12122349

A throttle can be installed on the intake pipe of a natural gas (NG)/diesel dual-fuel engine to control the excess air ratio of the air-fuel mixture by adjusting the air intake. Building on a previously proposed NG/diesel dual-fuel supply strategy using the adjustment of excess air ratio, this work further studied the effects of different injection timing schemes on output power, fuel efficiency, and pollutant emissions of a dual-fuel engine under low to medium load conditions. In the experiment, the engine was operated at a speed of 1600 r/min, under either low (27.1 N·m) or medium (50.6 N·m) loads, and the NG substitution rate was either 40%, 60%, or 80%. The effect of different injection timing schemes on the combustion performance of the engine under low to medium load conditions was studied based on in-cylinder pressure changes detected by a pressure sensor. Experimental results showed that under medium-speed low-load conditions and a NG substitution rate of 40%, setting the diesel injection timing to 27 °CA BTDC increased the engine output power by 9.03%, reduced the brake specific energy consumption (BSEC) by 13.33%, and effectively reduced CO, CO2, and HC emissions. Under medium-speed medium-load conditions with a NG substitution rate of 80%, setting the diesel injection timing to 25 °CA BTDC increased the engine output power by 14.62%, reduced the BSEC by 11.73%, and significantly reduced CO, CO2, and HC emissions.