Engine knock and combustion characteristics of a spark ignition engine operating with varying hydrogen and carbon monoxide proportions

Varying proportions of hydrogen and carbon monoxide (synthesis gas) have been investigated as a spark ignition (SI) engine fuel in this paper. It is important to understand how various synthesis gas compositions effect important SI combustion fundamentals, such as knock and burn duration, because in synthesis gas production applications, the compositions can vary significantly depending on the feedstock and production method.A single cylinder cooperative fuels research (CFR) engine was used to investigate the knock and combustion characteristics of three blends of synthesis gas (H₂/CO ratio); 1) 100/0, 2) 75/25, and 3) 50/50, by volume. These blends were tested at three compression ratios (6:1, 8:1, and 10:1), and three equivalence ratios (0.6, 0.7, and 0.8).It was revealed that the knock limited compression ratio (KLCR) of a H₂/CO mixture increases with increasing CO fraction, for a given spark timing. For a given equivalence ratio and spark timing, a 50%/50% H₂/CO mixture produced a KLCR of 8:1 compared to a 100% H₂ condition, which produced a KLCR of 6:1. The burn duration and ignition lag is also increased with increasing CO fraction. The results from this work are important for those considering using synthesis gas as a fuel in SI engines. It reveals that although CO is a slow burning fuel, higher CO fractions in synthesis gas can be beneficial, because of its increased resistance to knock, which gives it the potential of producing higher indicated efficiencies through the utilization of an engine with a higher compression ratio.     

Experimental investigation of Gasoline-Like Fuel obtained from waste lubrication oil on engine performance and exhaust emission

Experimental investigation on engine performance and exhaust emission of a gasoline engine fueled by Gasoline-Like Fuel (GLF) was performed in this study. The GLF was obtained from waste lubrication oil (WLO) using the pyrolitic distillation method. Firstly, the WLO collected in a tank was particulates removed by a refining process. The refined lubrication oil samples were taken into a reactor and blended with calcium oxide (CaO) 2, 4, 6, 8, and 10 wt.% to remove sulphur in the oil. The blended samples were heated in the reactor and then distilled to decrease sulphur and to produce fuel samples. Distillation tests and characteristics of the produced fuel such as density, flash point and lower heating value were examined. The experimental results indicated that the CaO at 2 wt.% had the highest effect on decreasing the amount of sulphur content in the lubrication oil. Fuels produced using 2 wt.% CaO were separated into two parts which were light fuel with 20 wt.% and heavy fuel with 60 wt.% of the total WLO. Remaining of the WLO is about 20 wt.%, which is rejected from the reactor. The light fuel, referred to as GLF and gasoline samples are used to investigate the effect of the GLF on performance and emissions of a 1300 cm³ spark ignited engine manufactured by Fiat. The engine used in the study has specifications of four-stroke and four cylinders, water cooled, fueled with carburetor and naturally aspirated. Each cylinder has a bore of 76 mm and a stroke of 71.5 mm. The experimental results showed that the GLF had a positive effect on brake power, brake thermal efficiency, mean effective pressure and specific fuel consumption. The GLF also raised CO emission and exhaust temperature, but it decreased hydrocarbon (HC) in the exhaust.     

Performance and durability of a generator set CI engine using synthetic and petroleum based fuels for military applications

The long term performance and durability evaluation of a compression ignition (CI) engine of a diesel power generator using ultra-low sulfur diesel (ULSD) and Synthetic Paraffinic Kerosene, (S-8) fuels have been investigated under military specifications. The brake specific fuel consumptions (BSFC) were 0.308 ± 0.013 and 0.267 ± 0.019 kg/kW-h for ULSD and S-8, respectively. The corresponding brake thermal efficiencies (BTE) were 0.287 ± 0.002 and 0.309 ± 0.005. Degradation of engine performance or engine part wear was not observed during these test periods. Analysis of lubricating oil suggests negligible engine part wear. The frequency and power output of the generator, however, were not as stable with S-8 as those with ULSD. These power and frequency instabilities can be attributed to higher volatility and lower density and viscosity of S-8, all of which affect the fuel injection characteristics.     

汽车发动机用AZ91合金的表面改性层及其性能

对汽车发动机用AZ91合金进行了等离子熔覆表面改性处理,对比分析了Al-Si涂层和Al-Si+Y涂层的显微组织和物相组成,并对改性层的硬度、耐磨性和耐腐蚀性能进行了比较。结果表明,Al-Si熔覆层主要含有α-Mg、Mg17Al12、Mg2Si和Al3Mg2相,Al-Si+Y熔覆层主要含有α-Mg、Mg17Al12、Al3Mg2、Mg2Si和Al2Y相;Al-Si和Al-Si+Y涂层的硬度都高于AZ91合金基体,Y元素的加入形成了细晶强化和弥散强化使得Al-Si+Y涂层具有较高的硬度;汽车发动机表面的耐磨性能从高至低依次为：Al-Si+Y涂层>Al-Si涂层>AZ91合金基材;等离子熔覆改性处理后的发动机缸体的耐腐蚀性能有所提高,其中Al-Si+Y涂层的耐腐蚀性能最好。     

发动机可变排量技术的研究进展

本文从产生背景、有效性、实现方法以及国内外发展现状对发动机可变排量技术进行了详细阐述,并提出了该技术存在的一些问题,为以后的发展和改进提供一定的依据。     

Emission and performance characteristics of an indirect ignition diesel engine fuelled with waste cooking oil

Biofuel has so far been backed by government policies in the quest for low carbon fuel in the near future and promises to ensure energy security through partially replacing fossil fuels. At present biodiesel is mostly produced by transesterification reaction from oil-seed feedstock and has to conform to ASTM D6751 specifications. Biodiesel sustainability has sparked debate on the pros and cons of biodiesel and the question of food security. The use of waste cooking oil such as palm and coconut oil in diesel engines is more sustainable if they can perform similarly to ordinary diesel fuel (B0). This paper presents the experimental study carried out to evaluate emission and performance characteristics of a multi-cylinder diesel engine operating on waste cooking oil such as 5% palm oil with 95% ordinary diesel fuel (P5) and 5% coconut oil with 95% ordinary diesel fuel (C5). B0 was used for comparison purposes. The results show that there are reductions in brake power of 1.2% and 0.7% for P5 and C5 respectively compared with B0. In addition, reduction of exhaust emissions such as unburned hydrocarbon (HC), smoke, carbon mono-oxide (CO), and nitrogen oxides (NO_x) is offered by the blended fuels.     

Computational modeling, validation, and utilization for predicting the performance, combustion and emission characteristics of hydrogen IC engines

Hydrogen-fueled internal combustion engines are considered to be more efficient and cleaner alternatives to their fossil-fueled counterparts. Reasonably fast and accurate predictive computational tools are essential for practical design, control and optimization of hydrogen engines. To serve for this broader purpose, a computational model, which has been widely used for gasoline and diesel engines, is investigated for its capability to simulate hydrogen engines. Specifically, fuel-specific sub-models are first incorporated by properly accounting for hydrogen’s distinct properties such as flame speed and burn rate. The accuracy of the model is then assessed by validating it in comparison to independent experimental data. Finally, it is utilized to quantify the environmental impact of exhaust gas recirculation. With these improvements, the present predictive model is shown to capture the measured engine performance and emission data well under different operating conditions. In particular, the variations of peak in-cylinder pressure, heat release rate, brake power, brake thermal efficiency, exhaust temperature, and NO_x emissions are predicted close to the measured values. With the addition of a proportional-integral-derivative controller to the engine model, exhaust gas recirculation level is varied, resulting in nearly an order of magnitude reduction in NO_x emissions during the present simulations.     

微型车用469Q汽油机的研发

概述了自行研发的微型车用469Q电控4气门汽油机的结构特点和采用的技术.对缸盖、气门室罩、正时传动、润滑系统和冷却系统等进行了分析和优化,对压缩比、配气相位和进气歧管长度等参数进行了试验优选.性能试验表明,汽油机动力性和经济性指标达到国内先进水平,排放指标达到欧Ⅲ标准.可靠性试验表明,汽油机运转正常,零部件无明显磨损,...     

单缸柴油机电控化的开发和试验研究

绿色环保、节能降耗是国内外各行业特别是发动机制造行业的重大课题,也是摆在内燃机技术工作者面前的历史使命。目前发动机的电控化是国内外降低排放的重要技术手段。单缸柴油机电控化的应用可提升单缸柴油机技术档次,进而满足节能降耗和绿色环保的要求。     

非道路用发动机尾气排放机外净化研究

本文论述了加强治理非道路用发动机尾气排放污染的重要性和迫切性,分析了治理非道路用发动机的尾气排放污染应采用的净化方法,并重点介绍了机外净化及其优点。在发动机试验台架上,选择了两种DOC型尾气净化器,进行了排放比对试验,验证了机外净化的效果。本文在最后总结了非道路用发动机尾气排放机外净化的特点。