Semivolatile Particle Emissions from Low Temperature Diesel Combustion


Premixed, low temperature combustion (LTC) has gained increasing attention from researchers because of its lower NOx and particulate matter (PM) emissions when compared to conventional compression ignition (diesel) combustion. Unfortunately, LTC produces higher concentrations of hydrocarbons and other high volatility compounds when compared to conventional diesel exhaust.

A model year 2012 General Motors 2.0 l automobile diesel engine is used to investigate PM composition, and the mechanics of formation of PM from partially-premixed low temperature combustion LTC. By using gas spectroscopy and flame ionization detection we are able to speciate compounds in the exhaust, and determine total hydrocarbon concentrations. By using particle sizing, conditioning, and counting instruments, we can investigate the volatility composition of the entire particle size range.

Preliminary results have shown that LTC emissions form PM in concentrations that vary greatly depending on exhaust dilution conditions. Our future goals include detection of organic acids in exhaust from LTC using gas chromatograph mass spectroscopy (GC/MS) and identification differences in conventional and LTC exhaust gas volatility using variable temperature flame ionization detection. The results of this research will further advance the combustion strategies of the future, improve the understanding of PM emissions from LTC, and enhance diesel after treatment efforts.