柴油机废气再循环电控系统的设计及应用

针对增压直喷柴油机开展废气再循环(EGR)技术的研究与应用,依据柴油机EGR控制系统的工作特点和功能要求,进行了控制系统的硬件电路设计和控制软件编写,实际控制效果良好,有效降低了氮氧化物的排放。     

柴油机废气再循环电控系统的设计及应用

针对增压直喷柴油机开展废气再循环（EGR）技术的研究与应用，以降低氮氧化物（NOx）排放。依据柴油机EGR控制系统的工作特点和功能要求，进行了控制系统的硬件电路设计和控制软件编写，实际控制效果良好。     

废气再循环对柴油机工作过程影响的模拟分析

根据实际柴油机的基本结构,建立了带有废气再循环(EGR)系统的增压直喷(TDI)柴油机的一维工作模型.将柴油机台架试验获得的最佳EGR率MAP图作为一维模型中EGR控制单元的控制MAP图,建立了模拟形式下EGR系统的控制单元,实现了柴油机在使用EGR后,不同工况EGR率条件下,EGR对柴油机工作全过程影响的一维模拟,模拟结果发现柴油机在使用EGR后空燃比、缸压、缸内温度都有所下降,缸内气体质量有所增加,与柴油机台架试验获得的结论吻合.     

YC4112ZLQ柴油机电控EGR系统的研究

为了降低柴油机的氮氧化物排放，对YC4112ZLQ增压中冷柴油机进行了电控废气再循环(EGR)技术的研究。试验研究了不同EGR率对发动机各个工况下性能和排放的影响规律，据此针对欧洲Ⅱ号标准优选出了各个工况下的最佳EGR率，并对最佳EGR率下的控制参数进行了电控标定。利用标定结果，设计了一套电子控制系统，用于该柴油机的实际运行。试验结果表明，与原机相比，加入EGR以后，在微粒排放略有增加的情况下，NOx排放下降12．9％，使13工况排放全面达到欧洲Ⅱ号标准的要求。     

柴油机使用EGR后供油提前角对排放特性影响的研究

研究了增压直喷柴油机供油提前角对排放特性的影响规律,分析了在柴油机采用废气再循环（EGR）技术降低NOX排放的同时,不同供油提前角对柴油机排放及油耗的影响情况。依据柴油机EGR控制系统的工作特点和功能,确定了柴油机的最佳供油提前角,并通过负荷特性试验对比分析,证实了在保证此最佳供油提前角的情况下,EGR综合降低排放效果可达到最佳。     

内燃机的废气再循环技术

介绍内燃机废气再循环(EGR)的工作原理、废气再循环量的评价指标EGR率、汽油机的EGR系统控制和柴油机EGR的效果及控制，以及采用EGR对柴油机工作过程和性能的影响。     

轨压和EGR率对柴油机性能的影响

基于一台采用EGR+DOC+DPF+SCR(EGR为排气再循环系统;DOC为柴油机氧化型催化器;DPF为柴油机颗粒捕集器;SCR为选择性催化还原)技术路线的欧Ⅵ排放柴油机,研究轨压和EGR率对柴油机经济性的影响,其中经济性分析以综合油耗为指标,综合油耗包括油耗、尿素消耗和再生消耗的柴油。研究表明:随着轨压升高,NOx排放升高,碳烟(Soot)排放降低,柴油机有效燃油消耗率(break specific fuel consumption,BSFC)变好,综合油耗出现拐点;不同轨压变化时,EGR率对柴油机排放的影响变化一致,随着EGR率的升高,NOx排放降低,Soot排放升高,BSFC变差,综合油耗变好,当EGR率在18%左右时,综合油耗最佳。同时,与非EGR路线的欧Ⅴ柴油机进行经济性对比,EGR路线对BSFC有一定程度恶化,综合油耗并没有恶化。     

EGR+DPF系统降低柴油机的排放

柴油机具有良好的动力性和经济性,汽车柴油机已成为发展趋势,但柴油机NOx和颗粒(PM)的高排放成为制约柴油车发展的因素之一。随着机动车排放法规的日益严格,降低NOx和颗粒的排放成为现阶段柴油机汽车的主要研究课题。废气再循环(EGR)技术是现今降低柴油机NOx排放的有效方法之一,应用颗粒捕集器(DPF)可以有效的降低尾气中颗粒的排放。本文介绍了EGR技术和DPF技术的原理、特点,对不同工况下EGR对NOx排放进行了分析,同时对不同工况下颗粒捕集器的再生效率进行了研究,结果表明适宜的EGR率和颗粒再生效率才能同时降低柴油机NOx和PM的排放。     

各缸废气再循环率不均匀性对柴油机排放影响的试验研究

针对一台由国五升级到国六的重型柴油机原始排放(无后处理系统)超过目标设定值的问题进行研究,提出了一种通过控制各缸废气再循环(exhaust gas recirculation,EGR)率不均匀性来降低柴油机原始排放的方法。建立了柴油机各缸EGR率不均匀性的排放测试试验台架和测试方法,通过分析排放万有特性曲线图确定所研究的进气总管EGR率和柴油机运行工况点,用CO2法在稳态工况下测量各缸EGR率,分析各缸EGR率不均匀对排放性能的影响,确定了达到企业原始排放目标设定值的各缸EGR率不均匀性范围,实现了通过控制各缸EGR率不均匀性来降低柴油机原始排放及降低满足国六排放法规后处理系统匹配难度和成本的目的。     

国Ⅳ柴油机EGR的控制与匹配研究

废气再循环(EGR)技术,作为一种成熟的排放控制策略,在国Ⅳ排放柴油机上已有广泛的应用,以某电控共轨柴油机为例介绍了EGR阀的结构和工作原理,以及在应用该技术的过程中如何实现EGR率的控制和EGR脉谱图的标定,通过试验对EGR系统进行了验证,表明该电控共轨柴油机能够达到国Ⅳ排放要求。     

高速车用柴油机废气再循环系统

采用废气再循环来降低氮化物的排放，目前已成为轻型车和轿车用柴油机排放达标的重要措施，本文以英国福特汽车公司在其1.8LTCI轿车用柴油机上所采用的废气再循环系统为例，详细介绍了相同类型的柴油机所用的废气再循环的控制原理，工作特点及其故障诊断的方法，为我国柴油机更好地利用这一技术来减少氮氧化物排放以满足日趋严格的排放法规提供一些借鉴。     

Performance and emission characteristics of CIE using hydrogen,biodiesel, and massive EGR

Hydrogen is considered as an excellent energy carrier and can be used in diesel engines that operate in dual fuel mode. Many studies have shown that biodiesel, which is sustainable, clean, and safe, a good alternative to fossil fuel. However, tests have confirmed that using biodiesel or hydrogen as a fuel or added fuel in compression ignition engines increases NOx concentrations. Cooled or hot exhaust gas recirculation (EGR) effectively controls the NOx outflows of diesel engines. However, this technique is restricted by high particulate matter PM emissions and the low thermal efficiency of diesel engines.In this study, gaseous hydrogen was added to the intake manifold of a diesel engine that uses biodiesel fuel as pilot fuel. The investigation was conducted under heavy-EGR conditions. An EGR system was modified to achieve the highest possible control on the EGR ratio and temperature. Hot EGR was recirculated directly from the engine exhaust to the intake manifold. A heat exchanger was utilized to maintain the temperature of the cooled EGR at 25 °C.The supplied hydrogen increased NOx concentrations in the exhaust gas emissions and high EGR rates reduced the brake thermal efficiency. The reduction in NOx emissions depended on the added hydrogen and the EGR ratios when compared with pure diesel combustion. Adding hydrogen to significant amounts of recycled exhaust gas reduced the CO, PM, and unburned hydrocarbon (HC) emissions significantly. Results showed that using hydrogen and biodiesel increases engine noise, which is reduced by adding high levels of EGR.     

涡轮增压柴油机变截面涡轮与单向阀废气再循环系统的计算研究

随着排放法规日趋严格,要求增大废气再循环系统ＥＧＲ率的调节范围,简单的ＥＧＲ系统难以满足要求。研究了变截面涡轮及排气节流阀配合单向阀的几种ＥＧＲ系统,并对变截面涡轮和排气节流阀在单向阀ＥＧＲ系统中的应用效果作了分析比较。     

Use of HOT EGR for NOx control in a compression ignition engine fuelled with bio-diesel from Jatropha oil

Environmental degradation and depleting oil reserves are matters of great concern round the globe. Developing countries like India depend heavily on oil import. Diesel being the main transport fuel in India, finding a suitable alternative to diesel is an urgent need. Jatropha based bio-diesel (JBD) is a non-edible, renewable fuel suitable for diesel engines and is receiving increasing attention in India because of its potential to generate large-scale employment and relatively low environmental degradation. Diesel engines running on JBD are found to emit higher oxides of nitrogen, NO_x. HOT EGR, a low cost technique of exhaust gas recirculation, is effectively used in this work to overcome this environmental penalty. Practical problems faced while using a COOLED EGR system are avoided with HOT EGR. Results indicated higher nitric oxide (NO) emissions when a single cylinder diesel engine was fuelled with JBD, without EGR. NO emissions were reduced when the engine was operated under HOT EGR levels of 5–25%. However, EGR level was optimized as 15% based on adequate reduction in NO emissions, minimum possible smoke, CO, HC emissions and reasonable brake thermal efficiency. Smoke emissions of JBD in the higher load region were lower than diesel, irrespective of the EGR levels. However, smoke emission was higher in the lower load region. CO and HC emissions were found to be lower for JBD irrespective of EGR levels. Combustion parameters were found to be comparable for both fuels.     

采用废气再循环降低柴油机NOX排放

本文论述了EGR降低柴油机NOX 排放的原理和采用该技术的必要性 ,探讨了柴油机NOX 和EGR率的测量方法 ,以及EGR的控制方法 ,并指出了与EGR相匹配的旨在全面控制柴油机排气污染物的技术。     

高低压EGR系统对低速柴油机性能和排放影响的研究

以某型6缸低速二冲程柴油机为研究对象,建立GT-POWER一维仿真模型,研究高、低压EGR系统对柴油机性能及排放的影响。研究结果表明:随着EGR率的上升,高压EGR系统中压气机运行点从中心高效区向低效区和流量减小的方向移动,而低压EGR系统的流量和压比变化较小;高压EGR系统缸内压力始终低于低压EGR系统,在低负荷时,导致燃烧速度和放热率峰值低于低压EGR系统;燃油消耗率随着EGR率的增加呈上升趋势,当EGR率增加到一定程度时燃油消耗率上升更明显,并且高压EGR系统燃油消耗率明显高于低压EGR;两种EGR系统都能降低NO_x排放,但相同EGR率时,高压EGR系统NO_x减排效果更好。     

采用排气再循环降低柴油机NO_x排放

本文论述了EGR降低柴油机NOx排放的原理和采用该技术的必要性;探讨了柴油机NOx和EGR率的测量方法。以及EGR的控制方法;指出了为满足排放法规对NOx排放的要求,必须采取综合技术措施。     

Hydrogen rich exhaust gas recirculation (H2EGR) for performance improvement and emissions reduction of a compression ignition engine

Hydrogen (H₂), being carbon free energy carrier, is best suitable for compression ignition (CI) engines with better performance and lower carbon derived emissions. Novelty of present study is the employment of low-cost catalyst (alumina) for production of H₂ reformate (hydrogen rich exhaust gas recirculation: H2EGR) in an indigenous catalytic reactor. Experimental tests were carried out on a CI engine under three conditions; base diesel, exhaust gas recirculation (EGR), and H2EGR. Results indicated that brake thermal efficiency of the engine with H2EGR was higher than EGR and comparable with base diesel operation. All carbon-based emissions including smoke emission decreased significantly with H2EGR than diesel and EGR operations. In addition, oxides of nitrogen emission (NO_x) also decreased by about 46% with H2EGR than base diesel operation. It is concluded that H2EGR is a promising option for CI engines for simultaneous reduction of both NO_x and smoke emissions along with the additional benefit of higher efficiency.