Ignition Criterion Studies on Lean and Diluted Mixtures for Clean Combustion in Automotive Engines

汽车发动机清洁燃烧稀混合气和稀释混合气的点火准则研究

• 批准号: RGPIN-2018-04004
• 负责人: Zheng, Ming
• 金额: $ 3.35万
• 依托单位: University of Windsor
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=712308
• 关键词: Ignition; Criterion; Studies; Lean; Diluted

Worldwide efforts with cutting-edge technologies are making significant progresses to improve the understanding, therefore the design and control of clean combustion engines. The lean and diluted fuel-air mixtures are effective to improve the efficiency and emissions of spark ignition (SI) engines, but are more difficult to ignite than a stoichiometric and homogeneous mixture. Traditionally, gasoline is injected during intake stroke, either at an intake port or directly into a cylinder. The cylinder charge usually reaches full homogeneity at the end of cylinder compression. Thereon, providing the air/fuel ratio (AFR) is stoichiometric, spark ignition succeeds with little difficulty, even with limited spark energy and duration. However, the burning efficiency of a stoichiometric cylinder charge is insufficient, and usually 6~8% of injected fuel skips combustion. An overall lean mixture can improve the burning efficiency, and reduces the reliance on intake throttling under partial loads. The use of exhaust gas recirculation (EGR) also reduces the pumping loss, while lowing the flame temperature and the nitrogen oxides (NOx) formation. When operating with lean and diluted mixtures, an engine needs to boost the intake air to retain full power. In synergy with automotive downsize and hybridization, the intake boost is also necessary for a small engine to produce more power at a higher efficiency. The proposed research establishes a strategy to study the criteria of ignition. Optically-accessible combustion cells will be used to study the ignition criteria of premixed mixtures, with precisely-controlled AFR, temperature, pressure, and dilution. Single cylinder research engines will be used to study the impact of in-cylinder flow and homogeneity, under independently-controlled fuel injection, intake boost, and EGR. Volatile fuels, including gasoline, ethanol, methane, and propane, will be injected at the intake port or directly into the cylinder, in single or multiple injection events. The spark and corona ignition with controls on the ignition energy, duration, events, sites, and volume will be investigated. The results of this research will provide guidelines for improving the fuel efficiency of SI engine clean combustion, specifically to the forming of a locally-ignitable mixture that encapsulates the gap of a sparkplug in transience to succeed the flame kernel formation and combustion. This research provides an ideal scenario for training HQP.

全球范围内利用尖端技术的努力正在取得重大进展，以提高对清洁内燃机的理解，从而提高其设计和控制。稀薄和稀释的燃油-空气混合物可有效提高火花点火（SI）发动机的效率和排放，但比化学计量的均质混合物更难点燃。传统上，汽油在进气冲程期间喷射，或者在进气口处或者直接喷射到气缸中。气缸充气通常在气缸压缩结束时达到完全均匀。因此，如果空气/燃料比（AFR）是化学计量的，即使火花能量和持续时间有限，火花点火也能毫无困难地成功。然而，化学计量气缸充气的燃烧效率不足，通常喷射燃料的6%~8%会跳过燃烧。整体稀薄的混合气可以提高燃烧效率，并减少部分负荷下对进气节流的依赖。使用废气再循环 (EGR) 还可以减少泵气损失，同时降低火焰温度和氮氧化物 (NOx) 的形成。当使用稀混合气和稀释混合气运行时，发动机需要增加进气量以保持全部动力。与汽车小型化和混合动力化相结合，进气增压对于小型发动机以更高的效率产生更多的动力也是必要的。 拟议的研究建立了研究点火标准的策略。光学燃烧室将用于研究预混合混合物的点火标准，并精确控制 AFR、温度、压力和稀释度。单缸研究发动机将用于研究独立控制燃油喷射、进气增压和 EGR 下缸内流动和均匀性的影响。挥发性燃料，包括汽油、乙醇、甲烷和丙烷，将在单次或多次喷射过程中从进气口喷射或直接喷射到气缸中。将研究火花和电晕点火以及对点火能量、持续时间、事件、地点和体积的控制。 这项研究的结果将为提高 SI 发动机清洁燃烧的燃油效率提供指导，特别是形成局部可燃混合物，该混合物瞬时封装火花塞间隙，以成功完成火焰核心的形成和燃烧。这项研究为训练 HQP 提供了一个理想的场景。