Numerical simulation and optimization design of the EGR cooler in vehicle

The EGR （exhaust gas recirculation） technique can greatly reduce the NOx emission of diesel engines, especially when an EGR cooler is employed. Numerical simulations are applied to study the flow field and temperature distributions inside the EGR cooler. Three different models of EGR cooler are investigated, among which model A is a traditional one, and models B and C are improved by adding a helical baffle in the cooling area. In models B and C the entry directions of cooling water are different, which mostly influences the flow resistance. The results show that the improved structures not only lengthen the flow path of the cooling water, but also enhance the heat exchange rate between the cool and hot media. In conclusion we suggest that the improved structures are more powerful than the traditional one.     

EGR在CA498柴油机上的试验研究

本文介绍了80C196单片机驱动比例电磁阀,进而对真空调节的EGR系统进行控制,来降低CA498的排放值,特别是NOX的排放值,并对其进行试验.结果表明:采用EGR系统后CA498的排放量下降明显.     

Controversial opinion: evaluation of <Emphasis Type="Italic">EGR1</Emphasis> and <Emphasis Type="Italic">LAMA2</Emphasis> loci for high myopia in Chinese populations

Functional studies have suggested the important role of early growth response 1 (EGR1) and Laminin α2-chain (LAMA2) in human eye development. Genetic studies have reported a significant association of the single nucleotide polymorphism (SNP) in the LAMA2 gene with myopia. This study aimed to evaluate the association of the tagging SNPs (tSNPs) in the EGR1 and LAMA2 genes with high myopia in two independent Han Chinese populations. Four tSNPs (rs11743810 in the EGR1 gene; rs2571575, rs9321170, and rs1889891 in the LAMA2 gene) were selected, according to the HapMap database (http://hapmap.ncbi.nlm.nih.gov), and were genotyped using the ligase detection reaction (LDR) approach for 167 Han Chinese nuclear families with extremely highly myopic offspring (<?10.0 diopters) and an independent group with 485 extremely highly myopic cases (<?10.0 diopters) and 499 controls. Direct sequencing was used to confirm the LDR results in twenty randomly selected subjects. Family-based association analysis was performed using the family-based association test (FBAT) software package (Version 1.5.5). Population-based association analysis was performed using the Chi-square test. The association analysis power was estimated using online software (http://design.cs.ucla.edu). The FBAT demonstrated that all four tSNPs tested did not show association with high myopia (P>0.05). Haplotype analysis of tSNPs in the LAMA2 genes also did not show a significant association (P>0.05). Meanwhile, population-based association analysis also showed no significant association results with high myopia (P>0.05). On the basis of our family- and population-based analyses for the Han Chinese population, we did not find positive association signals of the four SNPs in the LAMA2 and EGR1 genes with high myopia.     

不同EGR率对生物柴油发动机燃烧的数值模拟

以4100柴油发动机为研究对象,用fire软件模拟分析不同EGR对生物柴油燃烧性能和排放的影响。结果表明,应用EGR,能有效降低生物柴油发动机NOX的排放,但同时发动机的动力性和经济性会有一定幅度的下降;EGR率的增加会给柴油机的动力性、燃油消耗率、烟度的排放带来不同程度的负面影响,使柴油机的最大爆发压力及放热率峰值下降。     

EGR控制阀的控制系统研究与设计

为了降低柴油机氮氧化物(NOx)的排放、对发动机性能进行准确控制,研发了一种发动机废气再循环(EGR)新型控制系统,并对其硬件和软件进行了深入分析.测试结果显示,氮氧化物的排放量有了显著降低,验证了系统硬件和软件的有效性.     

废气再循环式柴油热风炉热交换系统的研制

介绍一种利用废气再循环以提高柴油热风炉热效率的方法,及其自行研制一种适用于温室内的全数字微机智能监控柴油热风炉废气再循环热交换系统。它由微电脑控制间歇地分流大部分、乃至全部已燃废气到进气管的装置。该系统采用新型的数字式温、湿度一体化传感器(LTM8901)和一线总线结构,由微处理器(89C51)自动智能监控。从系统的原理、结构设计出发,开发了独特用于柴油热风炉的废气再循环热交换系统,找到了最佳工作状况。当控制EGR率在50％～70％范围时,能提高热利用率17．6％,节约能源,并且还降低了排放污染。     

重型商用车应对国Ⅳ排放标准的技术

随着国Ⅳ标准在全国即将实施,国内商用车企业纷纷采取相应技术以应对国家强制标准。通过分析SCR技术和EGR＋DPF技术,指出两种技术的优劣,提出SCR技术更适合节能减排的大趋势。     

冷热EGR系统对点火式发动机性能影响的模拟研究

使用AVL_BOOST仿真软件,针对里卡多E6汽油机建立应用冷热EGR的一维燃烧模型,并通过发动机试验得到的燃烧压力进行验证,在此基础上分析冷热EGR对燃烧压力、进气质量、扭矩、比油耗的影响。结果表明,随着EGR率的提高,进气空气量、扭矩下降,采用热EGR时下降幅度更为明显;比油耗在EGR率小于10%时,略有改善,比油耗在EGR率大于10%时,随着EGR率的增大,比油耗剧增。