Emissions of a diesel engine using B20 and effects of hydrogen addition

•Performance and emissions of a diesel engine fueled by B20 and hydrogen are showed.•The presence of hydrogen does not affect significantly combustion durations.•Small amounts of hydrogen have favorable effects on B20 emissions except NOx.

The blended biodiesel with up to 20% biodiesel in petroleum diesel (B20) is considered nowadays as available in production. Previous studies investigating the effect of B20 on engine emissions led to some contradictory results. The present study continued the investigation on B20, 20% biodiesel (rapeseed methyl esters) blend effects and was also extended on B20 enriched with hydrogen. It was conducted on a conventional tractor diesel engine running alternatively with B20 and petroleum diesel at various speeds and full load and then, with the same fuels enriched with hydrogen, at 60% load and two speeds.It was found that compared with petroleum diesel, the engine fueled with B20 has significantly higher NOx emissions at all speeds and lower smoke and CO emissions, while both fuels combustion closely resembles. The addition of hydrogen to B20 by aspiration into the intake air flow at 60% load led to an increase of NOx emission and to lower smoke and CO emissions. Hydrogen addition to petroleum diesel showed a beneficial effect on NOx and CO emissions, while smoke was sensitive only at 2400 rpm.