改善车用涡轮增压发动机转矩特性的措施研究

在分析涡轮增压发动机低速转矩矩不足和瞬态响应特性较差原因的基础上,提出运用小型涡轮技术、双级增压系统、进气旁通增压系统、排气旁通增压系统、可变喷嘴环流通截面涡轮增压系统、节流阀式涡轮增压系统、双蜗壳通道涡轮增压系统、电子辅助涡轮增压（EAT）系统与涡轮、机械双增压（TSI）系统是改善涡轮增压发动机转矩特性的有效措施。     

利用现代CAD技术和有限元法进行增压器涡轮叶片变结构模态特性的研究

利用现代 Ｃ Ａ Ｄ技术建立了轴向后弯式增压器涡轮的实体模型,并用有限元法对其进行变结构模态特性研究,给出了不同截面叶片的曲面建模方法。针对涡轮叶片设计中常见的用于调频的结构变化类型,重点分析了在其它参数相同的情况下,不同截面形状涡轮叶片的模态特性以及同种截面形状的涡轮叶片在出口端将其沿轴向斜切一部分后模态特性的变化规律。试验表明：本文方法适用于涡轮叶片模态特性的系统研究,文中计算结果对类似涡轮的设计具有参考价值。文中建模和分析采用了美国 Ｓ Ｄ Ｒ Ｃ公司的 Ｉ Ｄ Ｅ Ａ Ｓ Ｔ Ｍ 软件。     

可变进排气供油正时涡轮增压柴油机的研究

提出了一种改善车用高速增压中冷柴油机低速大扭矩性能的自动变进排气供油正时（ＡＶＩＥＩＴ）涡轮增压系统,阐述了ＡＶＩＥＩＴ系统的基本原理。     

柴油机涡轮增压系统研究现状与进展

从不同方面分析了柴油机涡轮增压系统的研究现状与发展：在排气管系方面,为了改善８缸柴油机的低工况性能,推出了ＭＩＸＰＣ系统,它具有替代常规增压系统──定压系统、脉冲系统、脉冲转换系统及ＭＰＣ系统的趋势;在涡轮增压器方面,使用可变截面涡轮增压器是未来的发展趋势;在配气及供油正时方面,采用可变正时技术是未来的发展趋势,并且设计可变正时幅度大、结构简单、控制可靠的变正时机构是研究的核心,相应地出现了顾氏系统及ＡＶＩＥＩＴ系统;在专门的控制系统方面,发展了进排气旁通系统及相继增压系统,以改善高增压柴油机的低工况性能．文章指出,柴油机涡轮增压系统的发展须围绕如何改善高增压柴油机低工况性能这一核心问题展开,同时应综合考虑各方面因素,以发展新型有效的涡轮增压系统．     

舌形挡板变截面涡轮增压器涡轮蜗壳内气体流动的研究

本文在－模型上测试分析了舌形挡板变截面涡轮增压器涡轮蜗壳内气体流动规律，用丝线法和新探索的色泽法进行了蜗壳内气体流动显示，分析探讨了此种变截面涡轮增压器的工作机理，并将试验结果与计算数值进行了比较，获得了满意的结果，为设计优化舌形挡板变截面涡轮增压器提供了理论依据。     

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ＧＥＲＧ相匹配的旨在全面控制柴油排气污染物的技术。     

双舌形挡板变截面涡轮(VGT)的研究

介绍了双舌形挡板变截面涡轮的工作原理和这种变截面涡轮增压器在柴油机上的实用情况。用热线风速仪Ｘ形热膜探针测定了这种变截面蜗壳出口处的３维速度场,讨论了蜗壳出口Ｒｅ数变化即两个舌形挡板开启角度变化对能量利用的影响,并据此优化设计了双舌形挡板。将双舌形挡板变截面涡轮增压器与６１３０ＺＱ柴油机进行了匹配试验,证明与普通增压器相比,能够改善柴油机的扭矩特性和低速经济性,抑制了高速时的增压过量;与单舌形挡板变截面涡轮增压器相比,更适应车用柴油机的变工况时的需要。     

汽油机进行排气再循环时的参数优化试验研究

在ＥＱ６１００汽油机上进行的大量试验表明，各种负荷工况下排气再循环都能显著降低 ＮＯＸ排放，但ＨＣ 和ＣＯ排放及油耗率随ＥＧＲ率的变化关系则较为复杂，各工况下在下一个最优ＥＧＲ率。试验结果还表明，进行ＥＧＲ时的燃空当量比和点火提前角等参数也需要进行相应的调整和优化。这些措施为设计实用的ＥＧＲ系统提供了依据。     

JZG32A涡轮增压器与16SGT双燃料发动机的匹配

通过对１６ＳＧＴ双燃料发动机技术参数的分析、计算和优化,选配了ＪＺＧ３２Ａ国产涡轮增压器。配机试验表明,发动机的排气温度和热负荷明显降低,ＪＺＧ３２Ａ涡轮增压器的性能完全满足１６ＳＧＴ双燃料发动机的要求。     

车用增压器变截面无叶蜗壳和涡轮气动性能的研究

本文系统地研究了车用增压器变截面无叶蜗壳和涡轮的气动特性及其变化规律，揭示了影响蜗壳和涡轮特性的因素和机制，为变截面增压器的研制及其流动效率的改善提供了依据。     

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。     

增压柴油机实现废气再循环（EGR）系统的模拟计算研究

研究了涡轮增压柴油机使用废气再循环（EGR）面临如何在高负荷时以较低的成本和副作用获得降低NOx排放所要求的再循环废气量,提出了利用进排气压力波动实现涡轮增压柴油机废气再循环的单向阀、旋转阀和EGR短管3种EGR系统。模拟计算结构表明,采用上述3种EGR系统在高负荷甚至全负荷时,都可获得较大的EGR量。     

基于内部EGR率控制的柴油机排气凸轮型线仿真设计研究

以某6缸增压柴油机为研究对象,运用GT-Power仿真分析软件,在目标发动机2 200r/min和1 800r/min常用工况转速下,分析了内部热EGR率对NOx、PM、CO排放量的影响,研究得出了重型车用柴油机内部EGR率的最佳控制范围在10%左右。在此基础上,进行了二次排气凸轮开启相位对内部EGR率控制效果的仿真分析,总结出了二次开启排气凸轮的相位、升程、包角等特性参数对柴油机功率、燃油消耗率及EGR率的影响规律。最终确立了能够进行二次开启的、具有内部EGR功能的排气门凸轮设计方案,建立了排气凸轮基本型线的数学模型。针对目标样机开展了型线特性参数对燃油消耗率、功率及EGR率的影响分析。     

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.     

增压柴油机采用多级可变文曲利管式进气系统的实验研究

EGR技术应用在增压柴油机上出现了进排气压逆差导致应用有限的现象。本文采用将原有进气系统改造成由多个文曲利管并联组成的进气系统解决此问题。该系统一方面可由不同文曲利管之间的组合排列达到适应随工况变化的可变进气目的;另一方面,可以借助多个文曲利管的喉部压降能力吸引更多排气达到扩大EGR率的效果。通过流量模拟测试实验获得,采用MVVIPS较传统的串联式和分流式文曲利管系统都取得了更大的流通能力和压降能力;通过内燃机综合测试台架可知,采用MVVIPS系统后,试验用柴油机过量空气系统在不同转速下有着不同的变化;相比较原机的EGR系统,MVVIPS系统的EGR率在每个试验工况下都得到了不同程度的提高;动力性和经济性都在低、中转速下有小幅升高,但在高转速下与原机相差不大;根据稳态十三工况排放数据显示,采用MVVIPS系统后,NOx排放得到了有效控制,CO和微粒排放变化不大,HC排放在怠速及低工况范围内有着较明显的降低。     

Influence of high rates of supplemental cooled EGR on NOx and PM emissions of an automotive HSDI diesel engine using an LP EGR loop

Previous experimental studies on diesel engine have demonstrated the potential of exhaust gas recirculation (EGR) as an in‐cylinder NO_x control method. Although an increase in EGR at constant boost pressure (substitution EGR) is accompanied with an increase in particulate matter (PM) emissions in the conventional diesel high‐temperature combustion (HTC), the recirculation of exhaust gases supplementary to air inlet gas (supplemental EGR) by increasing the boost pressure has been suggested as a way to reduce NO_x emissions while limiting the negative impact of EGR on PM emissions. In the present work, a low‐pressure (LP) EGR loop is implemented on a standard 2.0 l automotive high‐speed direct injection (HSDI) turbocharged diesel engine to study the influence of high rates of supplemental cooled EGR on NO_x and PM emissions. Contrary to initial high‐pressure (HP) EGR loop, the gas flow through the turbine is unchanged while varying the EGR rate. Thus, by closing the variable geometry turbine (VGT) vanes, higher boost pressure can be reached, allowing the use of high rates of supplemental EGR. Furthermore, recirculated exhaust gases are cooled under 50°C and water vapour is condensed and taken off from the recirculated gases. An increase in the boost pressure at a given inlet temperature and dilution ratio (DR) results in most cases an increase in NO_x emissions and a decrease in PM emissions. The result of NO_x–PM trade‐off, while varying the EGR rate at fixed inlet temperature and boost pressure depends on the operating point: it deteriorates at low load conditions, but improves at higher loads. Further improvement can be obtained by increasing the injection pressure. A decrease by approximately 50% of NO_x emissions while maintaining PM emission level, and brake specific fuel consumption can be obtained with supplemental cooled EGR owing to an LP EGR loop, compared with the initial engine configuration (HP moderately cooled EGR). Copyright © 2008 John Wiley & Sons, Ltd.     

Effect of exhaust gas recirculation (EGR) temperature for various EGR rates on heavy duty DI diesel engine performance and emissions

DI diesel engines are well established today as the main powertrain solution for trucks and other relevant heavy duty vehicles. At the same time emission legislation (mainly for NO_x and particulate matter) becomes stricter, reducing their limit to extremely low values. One efficient method to control NO_x in order to achieve future emissions limits is the use of rather high exhaust gas recirculation (EGR) rates accompanied by increased boost pressure to avoid the negative impact on soot emissions. The method is based on the reduction of gas temperature level and O₂ availability inside the combustion chamber, but unfortunately it has usually an adverse effect on soot emissions and brake specific fuel consumption (bsfc). The use of high EGR rates creates the need for EGR gas cooling in order to minimize its negative impact on soot emissions especially at high engine load were the EGR flow rate and exhaust temperature are high. For this reason in the present paper it is examined, using a multi-zone combustion model, the effect of cooled EGR gas temperature level for various EGR percentages on performance and emissions of a turbocharged DI heavy duty diesel engine operating at full load. Results reveal that the decrease of EGR gas temperature has a positive effect on bsfc, soot (lower values) while it has only a small positive effect on NO. As revealed, the effect of low EGR temperature is stronger at high EGR rates.     

不同增压方式下EGR对高压共轨柴油机燃烧和排放的影响

在一台电控高压共轨柴油机上,采用单级增压、两级增压和可变几何截面增压3种增压方式,进行了高压冷却废气再循环(EGR)的燃烧与排放试验研究.结果表明,柴油机采用可变几何截面增压时,涡前与进气压差较低,泵气损失小,具有良好的燃油经济性;大负荷、等EGR率情况下,单级增压、两级增压和可变几何截面增压的缸内最大爆发压力和主燃烧...     

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.     

增大压缩比对国六柴油机性能的影响

通过理论分析和试验验证,研究增大压缩比对国六增压柴油机不同负荷工况点燃油消耗率的影响规律和对后处理系统性能的影响.结果 表明:增大压缩比可降低柴油机的燃油消耗率;在使用进气节流阀导致进气管压力低于环境压力的情况下,能够提供足够高的缸内压缩压力,但同时会导致排气温度降低,影响颗粒捕集器再生效率.