• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Analysis of stratified charge operation and negative valve overlap operation using direct fuel injection in homogeneous charge compression ignition engines.
【24h】

Analysis of stratified charge operation and negative valve overlap operation using direct fuel injection in homogeneous charge compression ignition engines.

机译：在均质充气压缩点火发动机中使用直接燃油喷射分析分层充气操作和负气门重叠操作。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The use of direct fuel injection in Homogeneous Charge Compression Ignition (HCCI) engines has shown potential to improve combustion and expand the engine operating range. The current study analyzes experimental and CFD simulation results to obtain enhanced insight into the nature of the stratified-charge HCCI combustion system in two different research engines: a CFR engine and a Yamaha engine.; In the direct-injection CFR-engine study, current simulations showed the mixture formation was strongly influenced by the momentum of the spray. Based on the modeling results, varying the injection timing from 300° to 180° bfTDC produced a small change in the charge stratification in the fuel-air mixture. Retarding the injection timing from 180° to 45° bfTDC showed a significant change in the distributions of equivalence ratio and gas temperature. The degree of charge stratification and the residence time that the mixture is exposed to high temperatures are of importance to avoid high NOx generation. Results from the kinetic rate calculations suggest that in a stratified air-fuel mixture, high NOx are likely to be generated from the regions where the equivalence ratio is greater than 0.5.; In the Yamaha engine study, the use of direct fuel injection during a negative valve overlap (NVO) period produces fuel reformation and NVO heat release that increases the gas temperature in the cylinder prior to intake valve closure. The amount of NVO energy release was found to be affected by the percentage and the timing of NVO fuel injection, the oxygen concentration in the exhaust, and the residual gas temperature. The findings in this study indicate that the use of NVO fuel injection has the ability to control the combustion phasing, expand the operating range, and improve the combustion efficiency for an HCCI engine.
机译：在均质充气压缩点火（HCCI）发动机中使用直接燃料喷射已显示出改善燃烧和扩大发动机工作范围的潜力。当前的研究分析了实验和CFD仿真结果，以增强对两种不同研究发动机（CFR发动机和Yamaha发动机）的分层装料HCCI燃烧系统性质的认识。在直接喷射CFR发动机研究中，当前的模拟表明，混合气的形成受喷雾动量的强烈影响。根据建模结果，将喷油时间从300°bfTDC更改为180°bfTDC会导致燃料-空气混合物中的充气分层发生很小的变化。将注入时间从180°bfTDC延迟到45°bfTDC时，发现当量比和气体温度的分布发生了显着变化。混合物暴露于高温下的电荷分层程度和停留时间对于避免高NOx产生很重要。动力学速率计算的结果表明，在分层的空气燃料混合物中，当量比大于0.5的区域可能会产生高NOx。在Yamaha发动机研究中，在负气门重叠（NVO）期间使用直接燃料喷射会产生燃料重整和NVO放热，从而增加进气门关闭前气缸内的气体温度。发现NVO能量释放的量受NVO燃料喷射的百分比和时间，排气中的氧气浓度以及残余气体温度的影响。这项研究的结果表明，使用NVO燃油喷射能够控制HCCI发动机的燃烧阶段，扩大工作范围并提高燃烧效率。

著录项

  • 作者

    Aroonsrisopon, Tanet.;

  • 作者单位

    The University of Wisconsin - Madison.;

  • 授予单位 The University of Wisconsin - Madison.;
  • 学科 Engineering Mechanical.
  • 学位 Ph.D.
  • 年度 2006
  • 页码 206 p.
  • 总页数 206
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 机械、仪表工业;
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号