F2008-09-057
A Comparative Analysis of Ethanol and Diethyl Ether as Supplementary Oxygenated Fuels in DI- Diesel Engines
In this research work the effects of two types of bio-based fuels, namely, Ethanol and Diethyl Ether (DEE) as supplementary oxygenated fuels on emissions and combustion characteristics of a DI diesel engine have been studied and compared.
Tests have been carried out with blending technique. Fuel formulations were prepared with addition of 5, 10 and 15%, on a volume basis, of Ethanol and DEE to the diesel fuel. The effect of Ethanol-Diesel fuel and DEE-Diesel fuel blends separately on the performance and emissions were tested and compared in a constant speed, single cylinder direct injection diesel engine at different loads.
Utilization of ethanol-diesel blend in different techniques and also blend of DEE with Diesel or Diesel-water emulsion has been investigated. However, comparison between the effect of ethanol-diesel and DEE-diesel blends on diesel engine is required and further investigations in details especially about combustion characteristics on DEE-Diesel blend are required.
Oxygen content of ethanol and DEE provided the potential of smoke reduction when using the respective blend. On the other hand the high difference between their cetane numbers (C.N.of ethanol is less than 8 and that of DEE is greater than 125) provided the reason for the difference in the NOx reduction trends and combustion characteristics but not as much as expected. The above said properties along with the other physico-chemical properties such as their high latent heat, volatility and lower heating value than diesel fuel resulted in different trends in their emission and performance characteristics.
This investigation aims at two purposes: the first is to find out the best amount of supplementary combination of ethanol-Diesel and DEE-Diesel by blending when lower emissions and better performance is desired without any major modifications to the engine and need of emulsifier or stabilizer for the blend. The second is to compare the effects of ethanol or DEE addition to diesel fuel on the performance and emissions characteristics. In this regard different experiments like stabilization test, performance, emission and combustion studies along with heat release calculations have been carried out. According to the results 10 percent, addition of Ethanol to Diesel fuel was chosen as the best (ED10) following the above-mentioned objectives. Amongst different DEE-Diesel blends, experimental data shows that about 5% addition of DEE to Diesel fuel gave the best results.
Comparative analyses of the results have shown that the increase in brake thermal efficiency when blending ethanol is more when compared to blending the same amount of DEE to diesel fuel. Furthermore, Ethanol is more effective in reducing smoke compared to DEE when it is blended with diesel fuel. It is also observed that for NOx reduction blending DEE is much more effective than blending ethanol to diesel fuel.
Poster presentation: Resources and ecology