Experimental and Numerical Study on Autoignition Characteristics of the Gasoline/Diesel/Ethanol and Gasoline/Diesel/PODE/Ethanol Fuels

Abstract

Polyoxymethylene dimethyl ethers (PODE) with high oxygen content and ethanol with high octane number are ideal additives for diesel and gasoline, respectively. Previous studies have shown that diesel/gasoline fuels and diesel/gasoline/PODE fuels can significantly reduce soot emissions. To further reduce soot emissions, ethanol was blended with these two fuels in this study and the effect of ethanol on fuel ignitability was investigated by experimental study and numerical simulation. Experiments were conducted in a cooperative fuel research engine and a cetane ignition delay instrument under various temperature and exhaust gas recirculation ratio. Results show that the effect of ethanol on chemical ignition delay is higher than that on physical ignition delay. With the addition of ethanol, the combustion phasing is retarded and the maximum apparent heat release rate of both low-temperature heat release and high-temperature heat release become lower. At the same time, an increase in the critical compression ratio (CCR) is observed with the addition of ethanol, while improving ignitability can be observed with the addition of PODE. It is worth noting that ethanol addition affects the CCR more for CCR of diesel/gasoline/PODE/fuels than that for diesel/gasoline fuels. Furthermore, kinetic simulation shows that there is an antagonism between ethanol and PODE during the decomposition process because OH is the key reactant in both ethanol and PODE decomposition.

Investigating the Effects of Water in Feedstock on the Energetic Efficiency of Producing Polyoxymethylene Dimethyl Ethers

“…In this work, two side products were observed: methanol and trioxane (TOX) [50]. The appearance of methanol can formally be explained by Equations (7) and (8). The appearance of trioxane is not delved into too deeply in this work.…”

“…PODE n of chain lengths n = 3-5 have suitable flash points [2] and melting points [3], which could reduce the soot and also, indirectly, NOx during the combustion process in compression ignition engines [4][5][6]. Thus, higher combustion efficiency could be achieved by blending PODE n in diesel [7,8]. Moreover, PODE n can be used as oxygenated fuels to direct oxidation fuel cells [9] and as green solvents for the chemical industry [10,11].…”

Combustion Study of Polyoxymethylene Dimethyl Ethers and Diesel Blend Fuels on an Optical Engine

“…Meanwhile, P100 always had the lowest PCP, PHRR and PCT. The higher oxygen content of PODE can release a large number of active free radicals during the combustion stage thereby promotes complete combustion and heat release [30,39,40]. The fuel injection quantity was fixed at 20 mg/cycle.…”

A Mini-Review on the Advances in the Kinetic Understanding of the Combustion of Linear and Cyclic Oxymethylene Ethers

“…This comparison shows that the most suitable OME n to be blended into conventional diesel are those with n = 3–5 (OME 3 , OME 4 , and OME 5 ). , A study of a mixture of OME 2–6 with a CN of 72 and its blends with diesel in a CI engine showed that better ignition, combustion, volatility, and reduced exhaust emissions can be achieved in comparison to conventional diesel fuel . The ignitability of a diesel fuel has been observed to be improved with the addition of OME 3–5 , and blending OME 3 in n -heptane/ethanol mixtures improved the combustion efficiency and reduced the pollutant emissions in a combustion vessel. , …”

“…7,27 A study of a mixture of OME 2−6 with a CN of 72 and its blends with diesel in a CI engine showed that better ignition, combustion, volatility, and reduced exhaust emissions can be achieved in comparison to conventional diesel fuel. 28 The ignitability of a diesel fuel has been observed to be improved with the addition of OME 3−5 , 29 and blending OME 3 in n-heptane/ethanol mixtures improved the combustion efficiency and reduced the pollutant emissions in a combustion vessel. 30,31 The storage stability of OME 3−5 was studied according to ASTM Standard D4625-14.…”