Performance and Exhaust Emission Studies of a Large LNG-Diesel Engine Operating with Different Gas Injector’s Characteristics

This research article reports the performances and emissions of a 12-litre LNG-diesel dual-fuelled engine when equipped with two different gas injectors. Natural gas is used as main fuel with a pilot amount of diesel for the ignition source. The main objective of this study is to replace the imported injector by the local product, while maintaining the performance compatibility. This means an economical benefit is obtained. Both gas injectors’ characteristics are investigated and found that characteristic of local product is relatively different from the imported one. The results show that injectors’ characteristic analysis must be separated into two ranges, including lower and higher engine speed ranges. Thus, the local injector must be then electronically adjusted in order to attain the engine performance and emission compatibilities. Consequently, it can operate satisfyingly, while no engine knocking is observed. The engine performance results between two injectors show minor differences, which are averagely less than 0.43%. The exhaust emissions also show small differences. The graphical presentations, the discussions and conclusions are also presented in this paper.