Combustion control and operating range expansion in an homogeneous charge compression ignition engine with direct in-cylinder injection of reaction inhibitors
Combustion control and operating range expansion in an homogeneous charge compression ignition engine with direct in-cylinder injection of reaction inhibitors
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DOI：
10.1243/146808705x30440
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发表时间：
2005-08
影响因子：
2.5
通讯作者：
H. Ogawa;N. Miyamoto;N. Kaneko;H. Ando
中科院分区：
文献类型：
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作者：
H. Ogawa;N. Miyamoto;N. Kaneko;H. Ando
摘要在均质充量压燃（HCCI）发动机中，从进气歧管引入具有两级着火特性的轻石脑油，并在压缩冲程早期直接喷射水或不具有低温氧化特性的低可燃性燃料，以抑制着火。它们的定量平衡可根据工况灵活控制，以优化点火正时。在较宽的工况范围内实现了无爆震、无失火的超低NOx和无烟燃烧。注水显著减少了低温氧化，从而抑制了充气温度的升高和由高温氧化引起的快速燃烧。快速燃烧被抑制的最高缸内气体温度的减少，由于水喷射，而燃烧效率受损。因此，需要将最大充气温度控制在极其有限的范围内，以在温和燃烧和高燃烧效率之间保持令人满意的折衷。醇类比其他含氧或不含氧的碳氢化合物、水和氢更能抑制低温氧化。甲醇的化学动力学模型表明，在低温氧化开始之前，OH自由基的减少，这可能是醇类抑制低温氧化的主要机制。
Abstract Light naphtha, which exhibits two-stage ignition, was induced from the intake manifold and water or a low-ignitability fuel, which does not exhibit low temperature oxidation, was directly injected early in the compression stroke for ignition suppression in an homogeneous charge compression ignition (HCCI) engine. Their quantitative balance was flexibly controlled to optimize ignition timing according to operating conditions. Ultra-low NOx and smokeless combustion without knocking or misfiring was realized over a wide operating range with water or alcohol injection. The water injection significantly reduced the low-temperature oxidation, which suppressed the increase in charge temperature and the rapid combustion caused by the high-temperature oxidation. Rapid combustion was suppressed by reductions in the maximum in-cylinder gas temperature due to water injection while the combustion efficiency suffered. Therefore, the maximum charge temperature needs to be controlled within an extremely limited range to maintain a satisfactory compromise between mild combustion and high combustion efficiency. Alcohols inhibit low-temperature oxidation more strongly than other oxygenated or unoxygenated hydrocarbons, water, and hydrogen. Chemical kinetic modelling with methanol showed a reduction of OH radical before the onset of low-temperature oxidation, and this may be the main mechanism by which alcohols inhibit low-temperature oxidation.