LPG／汽油双燃料发动机排放规律的试验研究

介绍LPG／汽油双燃料发动机的排放特性,主要分析燃用LPG时发动机的排放规律,并对比分析了燃用汽油和燃用LPG时发动机的排放规律。     

燃烧乙醇-柴油时发动机的性能与排放特性研究

在一台双缸直喷式柴油机上,对燃烧乙醇-柴油时发动机的燃油经济性和排放性进行试验。试验结果表明：与纯柴油相比,乙醇-柴油的当量燃油消耗率和CO排放量在较大负荷工况下有所减小,NOx和碳烟排放在各种工况下都显著降低,但HC的排放量增加;适当减小发动机的供油提前角,对提高燃油经济性和排放性有利。     

New vehicle fuel economy in the UK: Impact of the recession and recent policies

Interests in vehicle fuel economy have increased in the past few years with the implementations of more stringent CAFE standard in USA and mandatory carbon emission standard in the EU. We seek to understand the effects of recent policies such as restructuring of Vehicle Excise Duties and EU standard on new vehicle fuel economy in the UK. In the past few years there have been substantial fluctuations in income and fuel prices, offering an interesting testing ground to understand their impact on the demand for fuel economy in vehicles. We use a monthly dataset to find that the emission standard is the largest driver for fuel economy improvements in recent years. Also, contrary to some recent findings in Europe and in UK, we find that income has an effect and that the recession had some role in improving the fuel economy. The effects of fuel prices were relatively small. Restructuring of the VED also improved new vehicle fuel economy in the UK, but the scrappage scheme had no significant effect. Results indicate that both supply and demand side policies are effective in improving fuel economy, although quantitatively the emission standard appears more effective due to its stringency. It is also important to consider the effects of income while devising demand side policies.     

柴油机燃用生物柴油的排放特性研究

生物柴油是由植物或动物脂肪通过酯化反应而得到。由于生物柴油无毒，可生物降解和再生，因此受到越来越多的关注。许多研究表明生物柴油的性质和普通柴油非常相似，因此它能直接被用到发动机上而不需要改动发动机的结构。作者对柴油机燃用以豆油和乙醇生产的生物柴油和普通O^x柴油时的排放污染物进行了对比和分析。结果表明：相对于普通O^x柴油，在纯生物柴油的污染物排放中，除NOx排放基本不变外，CO、HC和碳烟等有害物质的排放大大降低(分别降低了29．08％、24．98％和43．1％)。生物柴油与柴油掺混燃烧时，排放降低的效果与生物柴油在柴油中的混合比例成正比。     

Experimental investigations on the effect of fuel injection parameters on diesel engine fuelled with biodiesel blend in diesel with hydrogen enrichment

Fuel injection pressure and injection timing are two extensive injection parameters that affect engine performance, combustion, and emissions. This study aims to improve the performance, combustion, and emissions characteristics of a diesel engine by using karanja biodiesel with a flow rate of 10 L per minute (lpm) of enriched hydrogen. In addition, the research mainly focused on the use of biodiesel with hydrogen as an alternative to diesel fuel, which is in rapidly declining demand. The experiments were carried out at a constant speed of 1500 rpm on a single-cylinder, four-stroke, direct injection diesel engine. The experiments are carried out with variable fuel injection pressure of 220, 240, and 260 bar, and injection timings of 21, 23, and 25 °CA before top dead center (bTDC). Results show that karanja biodiesel with enriched hydrogen (KB20H10) increases BTE by 4% than diesel fuel at 240 bar injection pressure and 23° CA bTDC injection timing. For blend KB20H10, the emissions of UHC, CO, and smoke opacity are 33%, 16%, and 28.7% lower than for diesel. On the other hand NOx emissions, rises by 10.3%. The optimal injection parameters for blend KB20H10 were found to be 240 bar injection pressure and 23 °CA bTDC injection timing based on the significant improvement in performance, combustion, and reduction in exhaust emissions.     

喷油器参数对柴油机排放性能的影响

通过对比试验分析研究了喷油器喷孔直径、启喷压力、垫片厚度等对CY6102BZQ型柴油机排放性能影响,为今后其他机型的开发研制提供理论依据和经验,可供同行参考。     

代用燃料发动机碳烟排放的试验研究

针对发动机机燃用LPG(液化石油气)和柴油混合燃料的碳烟排放问题进行了研究。发动机的碳烟排放量随着燃料中LPG所占比重的增加而迅速下降,但在掺比达到一定值时又开始有所上升,只要控制掺比在合适的范围内,就可以明显减少内燃机的碳烟排放。     

双燃料发动机(天然气/柴油)性能与排放的研究

以4102型柴油机为基础机，开发天然气／柴油双燃料发动机，试验研究引燃油量、喷油提前角对发动机排放和经济性影响，以及双燃料发动机与原柴油机性能和排放的比较。     

小缸径柴油机采用浅ω型燃烧系统的研究──燃烧率与NO_x排放

在两台采用浅ω型燃烧系统的高速柴油机上，对延迟供油的燃油消耗率、最高燃烧压力、NOx排放与排气烟度的影响进行了试验研究，并依据实测示功图采用现象学燃烧模型推求燃烧率与NOx生成，据此对试验结果作出理论解释。     

现代发动机冷却系统的发展趋势

传统发动机冷却系统由于自身特性影响,其工作性能受到限制。在部分负荷时会造成功率损失,而汽车在此工况下行驶的时间最长。本文介绍一些先进冷却系统的设计和系统的工作特点,这些系统既起到保护发动机的作用,又改善燃油效率和降低排放污染。