Investigation on Di-(2-Methoxypropyl) Carbonate Used as a Clean Oxygenated Fuel for Diesel Engine

Abstract

Utilization of oxygenated fuels has proven to be able to significantly control diesel engine exhaust emissions. Presented in this paper is a new oxygenated fuel di-(2-methoxypropyl) carbonate (DMPC), which was produced through transesterification reaction using dimethyl carbonate (DMC) and propylene glycol monomethyl ether (PGMME) as reactants as well as potassium hydroxide (KOH) as catalyst. Its structure characterization was completed through analyses with Fourier transform infrared (FT-IR), 1H nuclear magnetic resonance (NMR), and GC-MS analytical techniques. Further study was made about the effect of the oxygenate addition to diesel fuel on chemicophysical properties, combustion performances, and exhaust emissions characteristics. Experimental results displayed that the oxygenated fuel is mutually soluble with diesel fuel in any proportion at ambient temperature around 25 °C. With DMPC introduced to diesel fuel, kinematic viscosity decreases linearly, smoke point increases linearly, and flash point declines remarkably even under low content 5 vol %. Results of combustion test carried out on a single cylinder, DI diesel engine running at 1600 rpm and 2000 rpm showed that CO can be reduced by up to 60.0%, smoke can be lessened by up to 90.2%, while NOx increases by 4.4–14.0% as 15 vol % and 25 vol % of the oxygenate was added to a diesel fuel. Engine in-cylinder peak pressure increases somewhat and ignition delay duration becomes a little shorter. Both engine in-cylinder pressure rising rate and heat release rate increase noticeably during the premixed combustion.