A Comparison of Ethanol and Butanol as Oxygenates Using a Direct-Injection, Spark-Ignition Engine
A Comparison of Ethanol and Butanol as Oxygenates Using a Direct-Injection, Spark-Ignition Engine
复制标题
DOI：
10.1115/1.3043810
复制
发表时间：
2009-05
影响因子：
1.5
通讯作者：
T. Wallner;S. Miers;Steven S. McConnell
中科院分区：
文献类型：
--
作者：
T. Wallner;S. Miers;Steven S. McConnell
这项研究的目的是评估一个“如果”的情况下，使用丁醇作为替代乙醇的汽油操作校准的发动机中的一种替代品。本研究未对库存发动机校准进行变更。在一台现代直喷式四缸火花点火发动机上，对纯汽油、10%乙醇和10%丁醇混合燃料的燃烧特性、效率和排放进行了分析。数据是在发动机转速为1000 rpm至4000 rpm，负载从0 Nm（怠速）变化到150 Nm时采集的。三种燃料的燃烧特性，如放热率，50%的质量分数燃烧，并在指示平均有效压力的变化系数在低和中等负荷的发动机之间存在相对较小的差异。然而，在高发动机负荷下，丁醇混合物的降低的抗爆震性迫使发动机控制单元与汽油基线相比并且与乙醇混合物相比甚至更显著地延迟点火正时。由于较高的能量密度，表示归一化体积燃料流率的制动器比体积燃料消耗对于汽油基线燃料是最低的。与乙醇混合物相比，10%丁醇混合物具有较低的体积燃料消耗，正如预期的那样，基于能量密度差异。结果表明，10%乙醇和10%丁醇之间的管制排放差异不大。由于乙醇的高辛烷值和有效的抗爆特性，乙醇混合物产生了最高的峰值比NOx。总的来说，从排放和燃烧的角度来看，丁醇与乙醇表现相同的能力，以及燃料消耗的减少，最初似乎是有希望的。计划进行进一步的实验，以探索发动机的全工作范围和更高的丁醇混合比的潜在好处。
This study was designed to evaluate a “what if” scenario in terms of using butanol as an oxygenate in place of ethanol in an engine calibrated for gasoline operation. No changes to the stock engine calibration were performed for this study. Combustion analysis, efficiency, and emissions of pure gasoline, 10% ethanol, and 10% butanol blends in a modern direct-injection four-cylinder spark-ignition engine were analyzed. Data were taken at engine speeds of 1000 rpm up to 4000 rpm with load varying from 0 N m (idle) to 150 N m. Relatively minor differences existed between the three fuels for the combustion characteristics such as heat release rate, 50% mass fraction burned, and coefficient of variation in indicated mean effective pressure at low and medium engine loads. However at high engine loads the reduced knock resistance of the butanol blend forced the engine control unit to retard the ignition timing substantially, compared with the gasoline baseline and, even more pronounced, compared with the ethanol blend. Brake specific volumetric fuel consumption, which represented a normalized volumetric fuel flow rate, was lowest for the gasoline baseline fuel due to the higher energy density. The 10% butanol blend had a lower volumetric fuel consumption compared with the ethanol blend, as expected, based on energy density differences. The results showed little difference in regulated emissions between 10% ethanol and 10% butanol. The ethanol blend produced the highest peak specific NOx due to the high octane rating of ethanol and effective antiknock characteristics. Overall, the ability of butanol to perform equally as well as ethanol from an emissions and combustion standpoint, with a decrease in fuel consumption, initially appears promising. Further experiments are planned to explore the full operating range of the engine and the potential benefits of higher blend ratios of butanol.