Experiments and Modeling of Dual-Fuel HCCI and PCCI Combustion Using In-Cylinder Fuel Blending
Experiments and Modeling of Dual-Fuel HCCI and PCCI Combustion Using In-Cylinder Fuel Blending
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DOI：
10.4271/2009-01-2647
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发表时间：
2009-01-01
影响因子：
1.2
通讯作者：
Reitz, Rolf D.
中科院分区：
文献类型：
--
作者：
Kokjohn, Sage L.;Hanson, Reed M.;Reitz, Rolf D.
本研究探讨了通过改变燃料反应性来控制预混充量压燃（PCCI和HCCI）燃烧策略的可能性。使用汽油的进气道燃料喷射和柴油燃料的早期循环直接喷射的缸内燃料混合用于在高和低发动机负载下的燃烧定相控制，并且还有效地控制压力上升速率。研究的第一部分使用KIVA-CHEMKIN代码和减少的主要参考燃料（PRF）机制，以建议在两个发动机负荷（6和11巴净IMEP）下HCCI操作的优化燃料混合物和EGR组合。有人发现，最低的燃料消耗量不能实现使用纯柴油或纯汽油单独，和所需的最佳燃料反应性随着负载的增加而降低。例如，在11巴净IMEP下，发现用于HCCI操作的最佳燃料混合物和EGR率分别为PRF 80和50%。使用双燃料PCCI策略的发动机实验，该策略具有汽油的进气道燃料喷射和用常规柴油喷射器的柴油燃料的早期循环多次喷射（即，宽角度和大喷嘴孔）。实验结果证实，当使用优化的燃料混合物时，PCCI操作制度的扩展是可能的。在11巴操作点，NOx和烟尘分别类似于0.01g/kW-hr和类似于0.008g/kW-hr。也就是说，无需后处理即可轻松满足美国2010重型排放法规，同时实现50%的热效率。
This study investigates the potential of controlling premixed charge compression ignition (PCCI and HCCI) combustion strategies by varying fuel reactivity. In-cylinder fuel blending using port fuel injection of gasoline and early cycle direct injection of diesel fuel was used for combustion phasing control at both high and low engine loads and was also effective to control the rate of pressure rise. The first part of the study used the KIVA-CHEMKIN code and a reduced primary reference fuel (PRF) mechanism to suggest optimized fuel blends and EGR combinations for HCCI operation at two engine loads (6 and 11 bar net IMEP). It was found that the minimum fuel consumption could not be achieved using either neat diesel fuel or neat gasoline alone, and that the optimal fuel reactivity required decreased with increasing load. For example, at 11 bar net IMEP, the optimum fuel blend and EGR rate for HCCI operation was found to be PRF 80 and 50%, respectively. Engine experiments using a dual-fuel PCCI strategy with port fuel injection of gasoline and early cycle multiple injections of diesel fuel with a conventional diesel injector (i.e., wide angle and large nozzle hole) were performed. The experimental results confirmed that an extension of the PCCI operating regime is possible when optimized fuel blends are used. At the 11 bar operating point, NOx and soot were similar to 0.01 g/kW-hr and similar to 0.008 g/kW-hr, respectively. That is, US 2010 heavy duty emissions regulations are easily met without after-treatment while achieving 50% thermal efficiency.