Effect of hydrogen addition in diesel/natural gas dual-fuel combustion with late injection

In a previous work, the effectiveness of late pilot injection on improving combustion behaviour – in terms fuel conversion efficiency and pollutant emission levels diesel/natural gas dual-fuel engine was assessed. Then, an additional set experiments performed, aiming at speeding up process possibly without penalizing NOx levels. Therefore, hydrogen added to natural percentage equal 10%. Results show that addition has significant effect development specially during early stage combustion: ignition delay is shortened centre advanced, while duration increases when timing conventional values, remains basically unchanged for timings. Fuel only slightly penalized added. Moreover, it confirmed that, general, strategy with does not penalize efficiency; indeed, some cases, actually increases. Concerning regulated levels, again proven production: hydrocarbons carbon monoxide reduce as delayed, probably due higher temperatures reached into cylinder most part expansion stroke. adding always reduces their NO x , they are drastically reduced delaying injection; expected, promotes formation, but increase, evident timings, becomes marginal strategy. performance conditions can be further improved 10% gas.