The effects of dual-coil ignition and axial swirl on spark-assisted controlled autoignition
The effects of dual-coil ignition and axial swirl on spark-assisted controlled autoignition
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DOI：
10.1177/0954407013516104
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发表时间：
2014-06
期刊：
影响因子：
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通讯作者：
A. Cairns;Yan Zhang;Simon F. Dingle;Hua Zhao
中科院分区：
文献类型：
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作者：
A. Cairns;Yan Zhang;Simon F. Dingle;Hua Zhao
这项工作涉及一个双线圈点火系统的实验研究，以改善燃烧稳定性和控制在四冲程汽油控制自燃燃烧。点火系统基于先前在赛车应用中使用的“冗余线圈”设置，其中两个传统的感应线圈通过单独分配的二极管连接到公共火花塞。这种系统最近已被用于改进汽车火花点火发动机中废气再循环的耐受性，但它们的效果显然以前没有报道用于火花辅助控制的自动点火。因此，这项工作的基础是在低负荷下验证这种操作，其中火花辅助被最广泛地建议作为稳定受控自燃燃烧的一种手段。实验进行了使用一个热力学单缸研究发动机配备了电动液压，完全可变气门机构的入口和排气。这种气门机构主要用于引起负气门重叠，后来又用于研究非对称进气门操作和大体积气流中轴向涡流比增大的影响。这项工作的关键观察结果是，发现在低负荷受控自燃边界下运行时，每个线圈分段单次点火策略可显著提高燃烧稳定性，特别是当与增加的轴向涡流相结合以提高连续点火之间的可燃性时。总体而言，得出的结论是，该系统提供了一种新的方法，以确保在最低负载下的鲁棒控制自燃操作，具有额外的能力，以帮助控制燃烧噪声。
The work involved an experimental study of a dual-coil ignition system for improved combustion stability and control during four-stroke gasoline controlled autoignition combustion. The ignition system was based upon the ‘redundant-coil’ set-up previously used in motorsport applications, where two conventional induction coils are connected to a common spark plug via an individually assigned diode. Such systems have recently been used for improved tolerance to exhaust gas recirculation in automotive spark ignition engines, but their effects have apparently not been previously reported for spark-assisted controlled autoignition. The basis for the work was therefore to validate such operation at low loads, where spark assist has been most widely suggested as a means of stabilising controlled autoignition combustion. The experiments were undertaken using a thermodynamic single-cylinder research engine equipped with an electrohydraulic, fully variable valvetrain on the inlet and the exhaust. This valvetrain was primarily used to invoke negative valve overlap and later, additionally, to allow study of the asymmetric intake valve operation and the influence of the increased axial swirl ratio within the bulk gas flow. The key observation from the work was that a staged single strike per coil strategy was found to improve the combustion stability significantly when operating at the low-load controlled autoignition boundary, especially when combined with increased axial swirl to promote ignitability between successive strikes. Overall, it was concluded that the system provides a new method for ensuring robust controlled autoignition operation at the lowest loads, with additional ability to help to control the combustion noise.