An experimental and numerical study on diesel injection split of a natural gas/diesel dual-fuel engine at a low engine load

Development of a new reduced diesel/natural gas mechanism for dual-fuel engine combustion and emission prediction

Marine dual fuel engine modelling and parametric investigation of engine settings effect on performance-emissions trade-offs

Experimental analysis of NOx reduction through water addition and comparison with exhaust gas recycling

Adding hydrogen to natural gas is a promising way to improve the ignition stability and reduce the greenhouse gas emissions of pilot-ignition direct-injection natural gas engines. Most of the previous studies concerning hydrogen-enriched natural gas engines are focused on spark-ignition engines. The limited investigations on the addition of hydrogen in direct-injection natural gas engines are conducted by experimental method. Therefore, some detailed information on the in-cylinder combustion and emission formation process are left unknown. In this work, numerical simulations have been performed for the combustion process of a pilot-ignition direct-injection natural gas engine based on an integrated mechanism which is capable of describing the chemical kinetics involving diesel, natural gas, and hydrogen. Three-dimensional (3D) computational fluid dynamics simulations were conducted at different hydrogen blend ratios to explore the effects of hydrogen addition on the whole combustion process and the mole f...

Effects of Hydrogen Addition on the Performance of a Pilot-Ignition Direct-Injection Natural Gas Engine: A Numerical Study

An experimental investigation was carried out to study the effect of injection timing, diesel injection pressure, substitution rate of natural gas as well as engine load on the combustion and emission characteristics of an electronically controlled common-rail diesel/natural gas dual fuel engine. The tests were conducted at a fixed engine speed of 1200 r/min, while other parameters were varied in reference to different study purposes. It can be concluded from the experimental results that maximum in-cylinder pressure and maximum heat release rate as well as the combustion noise are generally increased as injection timing advances and injection pressure increases, while decreases at higher substitution rate. Concerning the emission characteristics, THC and CO emissions could be improved by advancing injection timing and increasing diesel injection pressure with penalty on NOx emissions; in addition, THC emissions are significantly increased at higher load and higher substitution rate, while CO emissions reduce considerably with increasing load but tend to be less sensitive to substitution rate; NOx emissions can be mitigated by application of higher substitution rate and get worse as engine load increases.

Menghan Li

Papers

Combustion and emission characteristics of an electronically-controlled common-rail dual-fuel engine