Characteristics of Isopentanol as a Fuel for HCCI Engines
Characteristics of Isopentanol as a Fuel for HCCI Engines
复制标题
DOI：
10.4271/2010-01-2164
复制
发表时间：
2010-01-01
影响因子：
1
通讯作者：
Simmons, Blake
中科院分区：
文献类型：
--
作者：
Yang, Yi;Dec, John;Simmons, Blake
与目前使用的乙醇作为汽油的生物组分相比，长链醇具有主要优点，包括更高的能量含量、更好的发动机相容性和更低的水溶性。生物燃料技术的快速发展使得成本有效地生产C-4 -C-5醇成为可能。这些高级醇可以显着扩大生物燃料的含量和潜在的替代乙醇在未来的汽油mixture.This研究的一些基本性质的C-5醇，异戊醇，作为燃料的HCCI engines。宽范围的发动机转速，进气温度，进气压力，和当量比进行了研究。结果与以前报道的汽油或乙醇数据进行了比较。对于给定的燃烧相位，在所有测试速度下，异戊醇需要比汽油或乙醇更低的进气温度，表明更高的HCCI反应性。与乙醇相似但与汽油不同的是，即使在非常低的发动机转速（350 rpm）或相当大的进气压力升高（200 kPa绝对值）下，异戊醇也不会显示两阶段点火。然而，异戊醇确实显示出与汽油相当的相当大的中温放热（CORR）。我们以前的工作已经发现，在实现高负荷而不爆震所需的延迟燃烧相位下，CORR对于保持燃烧稳定性至关重要。较强的CORR导致异戊醇的燃烧相位对进气温度变化的敏感性低于乙醇。在具有延迟燃烧相位的能力的情况下，在100和200 kPa的进气压力下分别用异戊醇实现了5.4和11.6 bar的最大IMEPg。这些负荷甚至略高于汽油所达到的负荷。异戊醇的CSTR取决于操作条件，并且通过同时增加压力和降低温度来增强。然而，提高温度似乎对大气压下的CORR影响不大，但它确实促进了热点火。最后，点火正时的当量比，这里称为Phi-灵敏度的依赖关系，在大气进气压力下测量，表明异戊醇的点火是几乎不敏感的当量比时，热效应被删除。这表明，部分燃料分层，这已被发现有效地控制HRR与两阶段点火燃料，可能无法很好地与异戊醇在这些条件下。总的来说，这些结果表明异戊醇作为HCCI燃料具有良好的潜力，无论是纯形式还是与汽油的共混物。
Long chain alcohols possess major advantages over the currently used ethanol as bio-components for gasoline, including higher energy content, better engine compatibility, and less water solubility. The rapid developments in biofuel technology have made it possible to produce C-4 -C-5 alcohols cost effectively. These higher alcohols could significantly expand the biofuel content and potentially substitute ethanol in future gasoline mixtures.This study characterizes some fundamental properties of a C-5 alcohol, isopentanol, as a fuel for HCCI engines. Wide ranges of engine speed, intake temperature, intake pressure, and equivalence ratio are investigated. Results are presented in comparison with gasoline or ethanol data previously reported. For a given combustion phasing, isopentanol requires lower intake temperatures than gasoline or ethanol at all tested speeds, indicating a higher HCCI reactivity. Similar to ethanol but unlike gasoline, isopentanol does not show two-stage ignition even at very low engine speed (350 rpm) or with considerable intake pressure boost (200 kPa abs.). However, isopentanol does show considerable intermediate temperature heat release (ITHR) that is comparable to gasoline. Our previous work has found that ITHR is critical for maintaining combustion stability at the retarded combustion phasings required to achieve high loads without knock. The stronger ITHR causes the combustion phasing of isopentanol to be less sensitive to intake temperature variations than ethanol. With the capability to retard combustion phasing, a maximum IMEPg of 5.4 and 11.6 bar was achieved with isopentanol at 100 and 200 kPa intake pressure, respectively. These loads are even slightly higher than those achieved with gasoline. The ITHR of isopentanol depends on operating conditions and is enhanced by simultaneously increasing pressures and reducing temperatures. However, increasing the temperature seems to have little effect on ITHR at atmospheric pressure, but it does promote hot ignition. Finally, the dependence of ignition timing on equivalence ratio, here called Phi-sensitivity, is measured at atmospheric intake pressure, showing that the ignition of isopentanol is nearly insensitive to equivalence ratio when thermal effects are removed. This suggests that partial fuel stratification, which has been found effective to control the HRR with two-stage ignition fuels, may not work well with isopentanol at these conditions. Overall, these results indicate that isopentanol has a good potential as a HCCI fuel, either in neat form or in blend with gasoline.