论文标题:废气再循环系统的研究
Study on the Exhaust Gas Recirculation (EGR) System
论文作者 孙巍
论文导师 蔡伟义,论文学位 硕士,论文专业 载运工具运用工程
论文单位 南京林业大学,点击次数 133,论文页数 57页File Size2409k
2003-06-01论文网 http://www.lw23.com/lunwen_324901607/ 废气再循环(EGR),氮氧化物(NO_X),发动机台架试验,自动控制
Exhaust Gas Recirculation (EGR),Nitrogen Oxide (NO_X),Engine bed-testing,Automation
随着汽车在我国的日益普及，汽车尾气污染成了一个严峻的社会问题。在这些污染物中，氮氧化物(NO_X)的污染尤显严重。而废气再循环(EGR)技术，是一种有效的降低发动机NO_X排放的方法。 本课题在DA462化油器式发动机上匹配了一个EGR系统，并进行了大量的台架试验。 结果表明：各种发动机工况下的EGR都能降低NO_X排放，但是发动机的有效功率Pe、有效扭矩Me和有效耗油率ge会受到不同程度的影响。因此，各种工况下都存在一个最优的EGR阀开度。 试验结果还进一步表明：在发动机较小负荷时，采用EGR方法能有效的降低NO_X排放量，但对发动机动力性的影响较大，不提倡采用EGR；在发动机中等负荷时，采用EGR方法能在较大的转速区间内，显著的降低NO_X排放量，并且对发动机动力性和经济性的影响不大，鼓励采用EGR；在发动机较大负荷时，EGR能在一定的转速范围内有效的降低NO_X排放量，并且对动力性的影响不大，因此要有选择的采用EGR；在发动机大负荷和全负荷时，采用EGR方法也能降低NO_X排放量，但对发动机动力性和经济性的影响很大，不宜采用EGR。 在试验的基础上，采用了可编程数据采集卡进行发动机工况参数的实时采集，并实现了对EGR系统的自动控制。
The pollution of automobile emissions has become a severe social problem whenautomobiles are more popularized in our country. Among those emissions, nitrogenoxide (NOx) is particularly harmful. The technology of exhaust gas recirculation(EGR) is known as an effective method to reduce the emission of NOx by the engine.An EGR system was fixed on a DA462 carburetor engine, and many tests have been done on the engine test bed.The results showed that EGR can reduce NOx emission under various operation conditions, but the effective power ( Pe) , the effective torque ( Me) and the effective gasoline consume rate (ge) will be affected. So there will be an optimum working state of the EGR valve under various operation conditions.It also showed that when the engine worked at a low load, EGR can effectively reduce NOx emission, but the power of the engine is seriously affected, so EGR was not advised to use in such case; when the engine worked at a moderate load, EGR can significantly reduce NOx emission under wide velocity range and had little effect on the power and economic performance of the engine, so EGR was encouraged to use in such condition; when a higher load was added to the engine, EGR can effectively reduce NOx emission under some velocity range, and the engine power was slightly affected, so EGR can be used in some conditions; when the engine worked at high load and full load, EGR can also reduce the NOx emission, but the power and economic performance of the engine badly influenced , so EGR shouldn"t be used.Through tests, a high-performance data acquisition card with programmable gain was used to gain the parameters of the engine operation conditions in real time, and the automation on the EGR system was realized.
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