基于微粒捕集器监测的柴油机排气特性参数研究

发布时间：2018-11-23 06:23

【摘要】：随着世界排放法规日渐严格,柴油机微粒捕集器以其良好的过滤效果和较低的使用环境要求等优点,已经在国内外柴油机后处理方面得到了广泛的应用,但是由于长期使用或者使用不当,微粒捕集器会发生堵塞和破损等故障。目前对微粒捕集器监测的研究还很少。因此,对基于柴油机微粒捕集器监测的柴油机排气特性的研究工作的开展十分必要。利用发动机性能仿真软件GT-Power建立了可以满足仿真计算要求的柴油机、柴油车和微粒捕集器仿真模型。利用建立的仿真模型,对稳态及道路工况下柴油机的排气温度特性进行研究,着重分析微粒捕集器不同状况对柴油机排气温度的影响；通过分析表明,在稳态和道路工况下,柴油机排气温度对微粒捕集器内微粒沉积量不敏感。对柴油机排气特性中另一个重要参数—排气压力的变化规律进行研究。从稳态及道路工况下柴油机排气压力特性的研究中得到,微粒捕集器前端排气压力与前后两端的排气压力差都可以作为微粒捕集器内的微粒沉积量的特征参数；在稳态工况下,还从平均排气压力和排气压力频谱两个方面对微粒沉积量对排气压力的影响进行分析,分析表明排气压力频谱的特征频率幅值比平均排气压力更适合作为微粒捕集器中微粒沉积量的特征参数。论文还通过仿真计算和实验研究的方法,研究了柴油机微粒捕集器状态对排气噪声的影响。通过仿真计算,着重研究了微粒捕集器中微粒沉积量对排气噪声的影响,研究表明,排气噪声频谱中排气脉动频率下的幅值随着微粒捕集器内微粒沉积量的增加而降低,可以考虑通过监测排气脉动频率下的幅值对微粒捕集器的微粒沉积量进行监测。通过实验方法,研究了微粒捕集器破损程度对排气噪声的影响,研究表明,随着微粒捕集器过滤体破损程度的增加,排气噪声频谱中排气脉动频率下的频率分量的幅值、两倍排气脉动频率下的频率分量的幅值都会随之增加,可以考虑通过监测两者之和对微粒捕集器破损程度进行监测；在一定的实验条件下,排气噪声频谱的峰值处的频率随着过滤体破损程度的增加而减小,可以考虑通过监测排气噪声频谱中的某些频率的变化对过滤体破损程度进行监测。论文开展的基于微粒捕集器监测的柴油机排气特性研究工作,能够为柴油机微粒捕集器堵塞或者破损的状态监测提供一定的依据,并可以为今后工程化的研究工作奠定一定基础。
[Abstract]:With the increasingly stringent emission regulations in the world, diesel particulate traps have been widely used in diesel engine aftertreatment at home and abroad because of their good filtration effect and low environmental requirements. However, due to long-term use or improper use, the particle trap will be blocked and broken. At present, there is little research on particle trap monitoring. Therefore, it is necessary to study the exhaust characteristics of diesel engine based on diesel particulate trap monitoring. A simulation model of diesel engine, diesel vehicle and particle trap was established by using engine performance simulation software GT-Power. In this paper, the exhaust temperature characteristics of diesel engine under steady and road conditions are studied by using the established simulation model, and the influence of particle trap on exhaust temperature of diesel engine is analyzed. The analysis shows that the exhaust temperature of diesel engine is insensitive to the amount of particulate deposition in the particulate trap under steady and road conditions. The variation of exhaust pressure, another important parameter in diesel engine exhaust characteristics, is studied. From the study of exhaust pressure characteristics of diesel engine under steady and road conditions, it is concluded that the exhaust pressure at the front end of the particulate trap and the exhaust pressure difference between the two ends of the particle trap can be used as the characteristic parameters of the particle deposition quantity in the particle trap. Under steady condition, the influence of particle deposition on exhaust pressure is analyzed from two aspects: average exhaust pressure and exhaust pressure spectrum. The analysis shows that the characteristic frequency amplitude of exhaust pressure spectrum is better than the average exhaust pressure as the characteristic parameter of particle deposition in particle trap. The influence of the state of diesel particulate trap on exhaust noise is also studied by simulation and experimental research. The effect of particle deposition on exhaust noise in particulate trap is studied by simulation. The results show that the amplitude of exhaust pulsation frequency in exhaust noise spectrum decreases with the increase of particle deposition in particulate trap. It can be considered that the particle deposition of the particle trap can be monitored by monitoring the amplitude of the exhaust pulsation frequency. The influence of the damage degree of particulate trap on the exhaust noise is studied by experimental method. The results show that the amplitude of the frequency component at the exhaust pulsation frequency in the exhaust noise spectrum increases with the increase of the damage degree of the filter body of the particulate trap. The amplitude of the frequency component will increase at twice the frequency of exhaust pulsation, so we can consider monitoring the damage degree of the particle trap by monitoring the sum of the two. Under certain experimental conditions, the frequency at the peak of the exhaust noise spectrum decreases with the increase of the filter body breakage degree. It can be considered to monitor the filter damage degree by monitoring the variation of some frequencies in the exhaust noise spectrum. The research work of diesel engine exhaust characteristics based on particulate trap monitoring can provide some basis for monitoring the state of diesel particulate trap blockage or breakage. And it can lay a certain foundation for the engineering research in the future.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TK421

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