An Experimental Investigation of the Effects of Diesel Fuel Injection Characteristics in a Heavy-Duty Direct Injection (HDDI) Diesel Engine

This experimental research aims to investigate the simultaneous effects of fuel injection characteristics on the combustion process in the D87 heavy-duty direct injection diesel engine. In this study, effects of 36 various injection strategies such as spraying pressure (1000, 1200, and 1400 bar), injection timing (6, 8, 10, and 12 CA BTDC), and fuel quantity (45, 90, 120, and 150 mm3</sup> per cycle) on combustion characteristics (MPPP and EGT), emissions formation (NOx and soot), and engine performance (brake power and BSFC) were explored. Results showed that increasing spraying pressure and quantity simultaneous with advancing fuel injection timing led to the increment of both MPPP and EGT and as a result, improvement of BSFC and brake power. However, due to lower AFR, higher combustion temperature, and shorter ignition delay period, both soot and NOx increased, which considered as a disadvantage of using this fuel injection strategy for the D87 diesel engine. In addition to that, for low fuel quantity per cycle (e.g., 45 mm3</sup>) due to shorter spraying duration, fuel injection timing and pressure have a great impact on engine performance because of determining the time of combustion phase and energy loss per cycle.