Effect of post-injection and alternative fuels on combustion, emissions and soot nanoparticles characteristics in a common-rail direct injection diesel engine

ABSTRACT

‏ Multiple injection strategies have been used in diesel engines to eliminate particulate emissions and increase the exhaust gas temperature. The effects of a post-injection (PI) strategy on engine performance, emissions, and soot nanoparticle characteristics in a common-rail (CR) diesel engine fueled with alternative fuels and diesel fuel were investigated. Alternative fuels were found to produce high the in-cylinder pressure and rate of heat release (ROHR) compared with diesel fuel for with and without (W/O) PI. The proposed PI strategy reduced the nitrogen oxide (NO_X) emissions while increasing the carbon monoxide (CO) and total hydrocarbon (THC) for all fuels tested. The alternative fuels (B, B20 and B16) reduced the engine emissions compared with diesel fuel for with PI and W/O PI. The soot nanoparticle characteristics (morphology and size distribution) decreased from the combined effect of PI and alternative fuels. It was observed that PI produced lower concentrations of particulate matter (PM) and modified the soot nanoparticle characteristics by decreasing the number (by an average of 7) and size (by an average of 5 nm) of primary particles. The combustion of B16 decreased the number by 13 and size by 19 nm of soot nanoparticles compared to that those emitted from combustion of diesel, B20, and biodiesel.

Graphical Abstract

KEYWORDS:

• Alternative fuel
• post-injection
• NO_X emissions
• nanoparticle
• soot
• particulate matter