Aspects of an experimental study of hydrogen use at automotive diesel engine

Hydrogen may represents a good alternative fuel that can be used to fuel internal combustion engines in order to ameliorate energetic and emissions performance. The paper presents some experimental aspects registered at hydrogen use to fuel a diesel engine, different substitute ratios being use in the area of 18–34%, at 40% engine load and speed of 2000 rev/min. The engine is equipped with an open ECU and the control of the cyclic dosses of diesel fuel and hydrogen are adjusted in order to maintain the engine power performance. The in-cylinder pressure diagrams show the increase of the maximum pressure with 17%, from 78.5 bar to 91.8 bar for the maximum substitute ratio. Also, values of maximum pressure rise rate start to increase for hydrogen addition, in correlation with the increase of fuel amount burned into the premixed stage, without exceed the normal values with assure the normal and reliable engine operation. Higher Lower Heating Value and combustion speed of hydrogen assure the increase in thermal efficiency, the brake specific energy consumption decreases with 5.4%–7.8% at substitute ratios of 20–27%. The CO2 emission level decreases with 20% for maximum hydrogen cyclic dose. In terms of pollutant emission level, at hydrogen use the emission level of the NOx decreases with 50% and the smoke number decreases with 73.8% comparative to classic fuelling at the maximum hydrogen cyclic dose.