满足非道路国四排放标准的大功率柴油机技术

某型大功率柴油机的排放值不满足非道路国四排放法规的要求,为此,对该柴油机燃油喷射系统、燃烧系统、增压系统和后处理系统进行优化设计和匹配。优化喷油策略,使柴油机的PM、CO和HC排放降低到非道路国四限值以下;安装选择性催化还原系统以降低NO_x排放。标定试验结果表明,升级后的柴油机满足非道路国四排放法规要求。     

内河船舶柴油机发展思路

介绍了我国内河船舶柴油机当前的现状,分析了其技术水平和面临的排放法规情况,对我国内河船舶柴油机提出了总的发展要求,以期不断提升我国船舶柴油机制造业的能力。     

国Ⅳ排放重型车用P型柴油机的开发

为了满足国Ⅳ和以后更高排放法规的要求,在现已批量生产的国Ⅲ排放重型车用A型柴油机的基础上,对气缸盖、活塞、燃油喷射系统、润滑系统和涡轮增压器进行了优化改进,同时增加了SCR后处理系统,研制开发出了可满足国Ⅳ排放法规的重型车用P型柴油机。试验结果表明,该柴油机的电控高压共轨系统和SCR后处理系统具有较好的应用适应性,满足国Ⅳ排放法规。     

满足欧Ⅱ排放法规CZ480Q柴油机技术对策

通过对CZ480Q型直喷式柴油机燃烧过程和排放特性的试验研究，系统地分析了燃烧室形状、喷油系统参数、后处理措施对柴油机燃烧过程和有害排放物的影响，探讨小缸径直喷式柴油机满足欧Ⅱ排放法规的技术对策；最终试验结果表明，改进措施改善了柴油机的燃烧过程，降低了柴油机有害排放物，排放指标均低于欧Ⅱ排放限值。     

东方红LR4M3-24柴油机满足非道路国II排放技术

简要介绍了国内外非道路排放控制法规及现状。针对法规要求开发了新一代东方红LR4M3-24柴油机。通过采用新结构活塞、喷油泵、喷油器等零部件及运用内部EGR技术，使该型柴油机的排放指标全面达到《非道路移动机械用柴油机排气污染物排放限值及测量方法》（I、Ⅱ阶段）中的Ⅱ阶段规定；且动力性、油耗、噪声、争性能均有所提高。     

使D6114车用柴油机排放达到欧洲Ⅰ号标准的试验研究

介绍了国内外车用柴油机的排放法规及限值标准;通过对排气污染物生成机理的分析,对D6114系列柴油机排放进行了大量试验研究,提出了具体的技术措施,如采取增压中冷、推迟喷油、高压喷射及优化燃烧室形状、采用小喷孔油嘴等措施,使其达到了欧洲Ⅰ号标准。     

36 000DWT多用途船加装SCR装置的方案设计与实船应用

针对某36 000 DWT多用途船NOx排放须符合IMO Tier Ⅲ排放法规的需求,在对几种可能技术分析论证的基础上,结合该船实际情况制定了加装SCR装置的方案:主机加装HP-SCR,发电机组加装LP-SCR.基于该方案对船舶结构和布置以及涉及的相关设备做了相应修改.系泊及航行试验表明:加装SCR装置后主机和发电机组的NOx 排放满足IMO Tier Ⅲ排放法规要求.     

满足单缸柴油机国-Ⅱ排放的技术难题与对策

结合单缸柴油机产品特点,分析了国内外小功率段柴油机排放法规标准的限值变化,针对单缸柴油机结构特点、行业现状及技术问题,阐明了低排放高性能单缸柴油机的研发难度和需解决的问题,给出了单缸柴油机优化性能及降低排放的技术路线和对策.分析表明:通过柴油机喷油系统、换气系统与燃烧室结构优化设计和匹配,特别是提高单缸柴油机用喷油系统的性能,优化燃烧过程的机内净化措施能满足GB19756、GB20891的排放限值的要求.     

非道路小型柴油机降低机油耗的研究

以186FA柴油机为样机,通过对曲轴箱负压、配缸间隙、气缸孔实际工作圆柱度及活塞环参数改进试验和分析,得出了小型单缸柴油机减少机油消耗量降低颗粒排放的技术措施和机理。经控制参数优化,186FA柴油机机油耗由2.31g/(kW·h)降至0.65g/(kW·h),柴油机颗粒排放降低至0.43g/(kW·h)。加装氧化催化剂后处理,柴油机达到了美国EPA Tire4排放限值和安全要求。     

降低CA498型柴油机排放的试验研究

论述了CA498型车用柴油机的排放控制方法及理论依据，进行了燃烧室、喷油器、喷油泵及气道的匹配试验，就这些因素对排放物的影响进行了分析，并确定了CA498型柴油机的优化匹配方案。十三工况的排放试验结果显示：通过优化匹配提高了CA498柴油机的性能指标，并使其整体排放水平达到了欧Ⅰ排放法规的要求，NOx、HC与CO的排放指标接近于欧Ⅱ限值。     

船用低速柴油机低压SCR系统台架试验研究

结合船用低速柴油机的技术特点设计了低压SCR系统并开展了台架试验研究。试验结果表明:所设计的SCR系统NO_x减排效果明显,NH₃逃逸量较小,满足相关法规要求;柴油机在加装SCR系统后排气压力损失满足设计要求,且对燃油消耗率影响较小。     

环境保护对船用柴油机的要求及其对策

阐述了环境保护对船用柴油机的要求,特别是内河使用的船用柴油机的要求。介绍了国内外环保法规对船用柴油机的限制及一些船用柴油机减少环境污染的措施。     

船用柴油机选择性催化还原系统设计及试验验证

结合船用中速柴油机开展选择性催化还原(selective catalytic reduction,SCR)系统的设计和性能试验验证,着重关注还原剂均匀分布、排气均匀度、系统稳定可靠控制及催化剂布置等方面,形成适用于船用环境的SCR系统设计方案.基于6L21/31中速柴油机D2以及E3循环工况开展SCR系统配机试验,结果...     

重型柴油机满足欧Ⅴ、欧Ⅵ排放法规的SCR后处理技术探讨

研究了国外重型柴油机排放法规的技术路线,分析了SCR系统的技术特点,并在此基础上探讨了满足欧Ⅴ以上排放法规的SCR后处理技术。指出SCR的设计理念在不断地更新换代,SCR的温度窗口不断扩大,SCR的体积不断缩小。发动机及后处理系统运行成本也在不断优化。     

Reduction of emissions in a biodiesel‐fueled compression ignition engine using exhaust gas recirculation and selective catalytic reduction techniques

This paper analyzes the emissions of a single‐cylinder diesel engine fueled with biodiesel, using selective catalytic reduction (SCR) and exhaust gas recirculation (EGR) techniques. The aim of this paper is to compare both EGR and SCR techniques, which were studied under different brake powers. Grape seed biodiesel was used as a test fuel. Experiments were performed by both techniques at different loads and rates to find out the performance change in the engine and the change in the emission rates using both the techniques. Then the observations from both the techniques were compared, concluding that both the techniques show a sufficient reduction in NOx. Using the abovementioned techniques, a reduction in hydrocarbon (HC), carbon monoxide (CO), carbon dioxide (CO₂), nitrogen oxides (NOx), and smoke was observed. The EGR technique is more suitable for low‐load engine vehicles, as it affects the efficiency of the engine with an increase in the fuel consumption, whereas the SCR technique is suitable for high‐load engines, which do not affect the efficiency of the engine with a decrease in the fuel consumption.     

Modelling of NOx emission factors from heavy and light-duty vehicles equipped with advanced aftertreatment systems

NO_x emission standards are becoming stringiest over the world especially for heavy-duty vehicles. To comply with current and future regulations some vehicle manufacturers are adopting exhaust aftertreatment systems known as Selective Catalytic Reduction (SCR). The catalysts are based on Vanadium (Va) and the reductant agent based on ammonia. However, Va is listed on the California Proposition 65 List as potentially causing cancer and alternatives are being studied. This paper presents a model based on neural networks that integrated with a road vehicle simulator allows to estimate NO_x emission factors for different powertrain configurations, along different driving conditions, and covering commercial, zeolite and mordenite alternatives as the base monolith for SCR. The research included the experimental study of copper based and iron based zeolites (ZSM5 and Cuban natural mordenite). The response of NO_x conversion efficiency was monitored in a laboratory for varying space velocity, oxygen, sulfur, water, NO_x and SO₂ emulating the conditions of a Diesel engine exhaust along a trip. The experimental data was used for training neural networks and obtaining a mathematical correlation between the outputs and inputs of the SCR system. The developed correlation was integrated with ADVISOR road vehicle simulator to obtain NO_x emission factors and to test each SCR system installed on light-duty and heavy-duty vehicles for standardized driving cycles and real measured driving cycles. Despite having lower NO_x conversion efficiencies than the CATCO in the ETC/ESC and NEDC cycles, FeZSM5 maintain the Euro regulation level. Therefore FeZSM5 can be a possible candidate as far as pollutants regulation is considered.     

Combining GTL fuel,reformed EGR and HC-SCR aftertreatment system to reduce diesel NOx emissions. A statistical approach

An ultra-low sulphur diesel (ULSD) fuel and a synthetic gas-to-liquid (GTL) fuel, besides different types of standard and reformed EGR, were evaluated in a single-cylinder, direct injection, diesel engine equipped with hydrocarbon-selective catalytic reduction (HC-SCR) aftertreatment system. The results obtained were statistically analysed (at 95% statistical significance) to identify the most significant factors that affect NO_x emissions and to search for the optimum operation conditions in order to minimize these emissions. For that purpose, a fully crossed factorial experimental design was used, including two different engine speeds (1200 and 1500 rpm), two engine loads (25% and 50%), and four EGR/REGR ratios (0%, 10%, 20% and 30%) resulting in almost one hundred tests. An optimal combination of fuel type, REGR type and REGR ratio was proved to reduce around 89–95% of the reference NO_x emissions. In general, at 25% engine load GTL fuelling combined with the reformed EGR with the highest hydrogen content was found the most desirable, as the hydrogen sharply increased the NO_x conversion in the SCR catalyst. Differently, at 50% load standard EGR was sufficient to reach high NO_x reductions. These findings may be used for the implementation of a system on-board capable to switch from EGR to REGR, which will help engine manufacturers to meet the future emission regulations.     

NOx reduction studies on a diesel engine operating on waste plastic oil blend using selective catalytic reduction technique

The constant escalation in the consumption of petroleum products has compelled researchers to discover for new alternative fuels which can be successfully incorporated in the existing automotive engines. Oil derived from waste plastics is one such alternative, which not only ensures longevity of fossil fuels but also assists in bringing down the hazardous impacts caused by the improper disposal of plastic wastes. This work focuses on the utilization of valuable energy of toxic non-biodegradable waste plastics to lucratively be used as an alternative fuel. An attempt was further made to reduce the NO_X emissions which increased with the use of waste plastic oil blend. The main objective of this experimental investigation is to study the performance & emission characteristics of a twin cylinder CRDI engine subjected to selective catalytic reduction (SCR) after-treatment technique. Different flow rates of ammonia as a reducing agent were tested and concluded that a flow rate of 0.5 kg/hr furnishes optimum results. A comparison of NO_X reduction efficiency was also made between SCR and EGR techniques. The comparison eventually indicated that SCR gives better NO_X conversion efficiency at higher loads without any adverse effect on the engine performance while operating on Waste Plastic Oil blend (P30).     

大功率柴油机尿素-选择性催化还原系统混合器仿真与试验研究

针对大功率柴油机选择性催化还原技术(SCR)应用需求,设计了两种混合器方案,两方案的差别在于是否在喷射点前安装前置混合器。利用计算流体动力学(CFD)技术对两方案的气流轨迹、尿素分解率、分布均匀性及压力损失进行了仿真分析,并进行D2排放循环测试验证两方案的NO_x转化效率。仿真及试验结果表明:安装前置混合器可以产生旋流,促进尿素液滴与气流充分混合,提高尿素分解率和NH_3分布均匀性,压力损失增高;安装前置混合器能够提高SCR催化器的NO_x转化效率,并可以通过标定优化使NO_x比排放满足欧盟第五阶段排放限值要求。研究表明,前置混合器更能适应当前及未来大功率柴油机NO_x排放法规限值要求。     

Performance of multi-cylinder diesel engine fueled with mahua biodiesel using Selective Catalytic Reduction (SCR) technique

India is mainly an agricultural country. For irrigation, the farmers are primarily dependent on diesel engines which run on immaculate diesel. In order to reduce the consumption of diesel, oxygenated fuel additives seem to be a good proposition. In this connection, biodiesel is one of the best choices and this study is an attempt in that direction. Of the various non-edible vegetable oils available for making biodiesel, Mahua oil (Madhuca Indica) is preferred since it is widely available across the country. The problem with biodiesel is the higher emission of oxides of nitrogen (NO_x). NO_x emissions can be controlled with Ad-Blue (Urea) solution. Fortunately, for the irrigation sector, it may be considered as a blessing in disguise since, Urea which is used to control the NOx emissions is used as a fertilizer. In this work an experimental study has been carried out to assess the suitability of selective catalytic reduction (SCR) technique in reducing NO_x. To arrive at accurate results, property characterization has been carried out for various blends. Tests were conducted on a multi-cylinder water cooled diesel engine at 2400 rpm. For loading an eddy current dynamometer was used. The injection nozzle opening pressure (NOP) was set to 220 bar with constant static injection timing (SIT) of 18° before top dead center (bTDC). This study presents the results at full load, employing SCR technique. The results were compared with conventional engine results under same operating condition where no reduction technique was employed. It was found that there was a significant reduction in NO_x (around 3.91%) when the engine was operated with 25% biodiesel, thereby saving 25% diesel. This study establishes that SCR technique with 25% biodiesel addition as a viable option without any modification in the engine and without any compromise on the engine performance. Therefore, this option can be considered as sustainable one in agricultural operation.