A comparative study on alcohol-diesel blended fuels in a common rail diesel engine: Combined effects of carbon numbers, oxygen content, and molecular structure

Abstract

Abundant alcohols, including ethanol, propanol, butanol, and pentanol, are expected to be used in compression ignition engines to ease the shortages of fossil fuel. The various alcohols have quite a different combustion and emission characteristics in the engine due to the changes in molecular structures. In this paper, a series of experiments were conducted on a modified common-rail diesel engine fueled with diesel/alcohols blended fuels in a wide operating range. The effects of alcohol chain length, oxygen content, and molecular structure on engine combustion and emission characteristics are studied systematically. The experimental results show that the blending of alcohols increases the peak values of in-cylinder pressure and maximum pressure rising rate. Besides, the combustion duration and ignition delay are mainly affected by oxygen content and isomer structure. The addition of short-chain alcohols will significantly reduce the total mass of particulate matter (PM) emissions, while the CO and HC emissions increase appropriately. The CO, HC, aldehydes, and ethylene emissions are mainly affected by carbon chain length and isomer structure. For PM emissions, the carbon chain length, molecular structure, and oxygen content of alcohol fuels have different influences on PM number, PM mass, and particle size distributions. The shorter carbon chain of alcohol leads to smaller particle size, and higher oxygen content leads to lower total particle mass.

Performance and Emission Characteristics of a High-Speed Diesel Engine Using a 20% Palm Oil Ester and Ethyl Alcohol Blend

“…In terms of engine characteristics, the combinations of diesel and alcohol changed the values of BTE and BSFC. Particularly, diesel mixed with butyl alcohols (N-butanol and iso-butanol) by less than 10% had a higher BTE than diesel baseline and its combination with ethyl alcohols for the same mixture proportion because the CV of butyl alcohols was higher than that of ethyl alcohols and other alcohols [19][20]. Nevertheless, diesel blended with ethyl alcohols resulted in better combustion characteristics and lower engine wear than diesel mixed with other alcohols [24][25].…”

“…For adding other oxygenated fuels in terms of alcohols, some researchers have investigated the physical properties of diesel mixed with alcohols via emulsification. Especially ethyl alcohols (ethanol and ethyl acetate) produced from starchbased crops by fermentation are lower in cost and less toxic than other alcohols, such as butyl, methyl, and propyl alcohols [19][20]. The previous studies [19][20][21][22][23][24][25] investigated the fuel properties and the operating behavior of diesel engines using various proportions of diesel and alcohols (ethanol, ethyl acetate, butanol, methanol, propanol, etc.…”

“…Nevertheless, diesel blended with ethyl alcohols resulted in better combustion characteristics and lower engine wear than diesel mixed with other alcohols [24][25]. Importantly, the releases of UHC, CO, and NO by mixing ethyl alcohols were lower [19][20][21][22].…”

Investigating the impact of alumina nanoparticles in coconut oil distillate biodiesel to lessen emissions in direct injection diesel engine

“…The nanoparticle additives reduce engine emissions and fuel consumption. Hence, BCFAD can be used along with fuel additives to improve the engine performance 14 .…”

Performance of a CRDI Diesel Engine Generator Fueled with B20-Bioethanol-Ethyl Acetate Blends

“…For using bioethanol with CRDI diesel engines, the earlier examinations of engine characteristics fueled with diesel mixed with increasing bioethanol from 5 to 15% showed the reduction of engine performance. NO and BS emissions were reduced with adding bioethanol, but the escalation of bioethanol more than 10% led to the changes of CO [16,17]. The studies of neat biodiesel and diesel blended with biodiesel proportions when combined with increasing bioethanol from 5 to 15% led to the changes of engine characteristics.…”