摘 要

随着化石能源的短缺以及环境的污染，能源和环境问题已经变成阻碍我国经济发展的最大难题。目前，利用生物质能源代替化石能源成为解决这一问题的重要手段。2-甲基呋喃（MF）由于其粘度低，雾化好，辛烷值较高，受到了科学家的广泛研究。

本研究在四缸四冲程水冷柴油机上进行，将发动机转速保持恒定为1800转/分，改变发动机的负荷，研究负荷以及MF质量分数对混合燃料燃烧及排放的影响。实验表明：

1. 在发动机负荷保持不变的情况下，在纯柴油中掺入MF可以进一步延长着火延迟期，并且是随着燃料混合比的增加而不断延长。另外，当混合燃料中MF质量分数不断增大时，燃料的放热率峰值也会相应的增加。
2. 纯柴油中添加MF可以很明显地延长燃料的着火延迟期并且缩短它的燃烧持续期。
3. 在发动机处于低负荷状态时，随着负荷的增长，M40的燃烧持续时间反而下降；所以混合燃料中过高的MF混合比并不适用于柴油机。
4. 与纯柴油相比，所有混合燃料的有效热效率更高，当量燃油消耗率更低（M40除外）。
5. 当发动机处于低负荷状态时，MF/柴油混合燃料和纯柴油的NO_X排放相差不大，都很低；当发动机处于中高负荷时，MF/柴油混合燃料的NO_X排放比纯柴油的要高很多，并且是随着MF混合比的增大NO_X排放也增多。
6. 不论是哪种负荷下，M10的HC排放最低；当发动机处于低负荷时，纯柴油的CO排放最低，而且HC和CO的排放都随着MF混合比的增大而增多；当发动机处于中高负荷时，M10、M20、M30、M40和纯柴油的HC和CO排放相差不大。
7. 在柴油中混入适量的MF，可以显著减小燃料的烟度值。

关键词：2-甲基呋喃；柴油；混合燃料；发动机负荷；燃烧和排放

Abstract

With the shortage of fossil fuels and the pollution of the environment, energy and environmental issues have become the biggest problems that hinder the development of China´s economic. At present, using biomass energy instead of fossil energy has become an important means to solve this problem. Because of having low viscosity, good atomization and high octane number, the 2-Methylfuran (MF) has been widely studied by researchers.

In this study, all experiments were carried out on a four-cylinder, four-stroke and water-cooled diesel engine. The effects of the load and MF ratio in the mixtures on the combustion and emission performance of the blends were studied by keeping the engine speed constant at 1800 rpm and varing the engine load. The results showed that:

1. when the engine load remained unchanged, mixing MF with pure diesel can prolong the ignition delay period much further, and the ignition delay period will be extended with the increase of MF mixing ratio. In addition, with the mass integral of MF increasing in the mixed fuel, the peak heat release rate of fuel will also increase.
2. Adding MF to pure diesel can prolong the ignition delay period significantly and shorten the combustion duration.
3. The combustion duration of M40 decreased with the increase of load when the engine was under low load. Therefore, high MF mixing ratio in mixtures was not suitable for diesel engines.

(4)Compared with pure diesel, all blends had higher effective thermal efficiency and lower equivalent fuel consumption rate (except M40).

(5) Both the blended fuel and the pure diesel ,their NOx emissions were very low when the engine was under low load. The NOx emissions of the blended fuel were much higher than the pure diesel, and the NOx emissions increased with the increase of the MF mixing ratio when the engine was under medium and high load.

(6) M10 had the lowest HC emissions regardless of the load. The CO emissions of pure diesel were the lowest, and both the HC and CO emissions increased with the increase of the MF mixing ratio when the engine was under low load . The HC and CO emissions of M10, M20, M30, M40 and pure diesel were similar when the engine was under medium and high load.

(7) Mixing MF with diesel could reduce the emission of smoke .

Keywords: 2-methyl furan; diesel; mixed fuel; engine load; combustion and emissions

目 录

第1章 绪论 1

1.1 引言 1

1.1.1 能源短缺 1

1.1.2 环境污染 2

1.2 MF燃料 2

1.3 研究现状 4

1.4 研究的意义 6

1.5 研究内容和目的 6

1.6 本章小结 6

第2章 实验测试系统及方案 7

2.1 实验发动机 7

2.2 仪表设备 7

2.2.1 涡流测功机 7

2.2.2 燃烧特性测试 8

2.2.3 排放特性测试 9

2.3 数据处理 9

2.3.1 MF/柴油的混合比 9

2.3.2 MF/柴油混合燃料的低热值 10

2.3.3 经济性数据处理 10

2.4 实验燃料和方案 10

2.5 本章小结 11

第3章 MF/柴油混合燃料的燃烧特性分析 12

3.1 缸内压力和放热率 12

3.2 最大缸内压力 14

3.3 着火延迟期 14

3.4 燃烧持续期 15

3.5 当量燃油消耗率（BSEC） 16

3.6 有效热效率 16

3.7 本章小节 17

第4章 MF/柴油混合燃料的排放特性分析 19

4.1 NO_X的排放 19

4.2 HC的排放 19

4.3 CO的排放 20

4.4 烟度 21

4.5 本章小结 22

第5章 全文总结和工作展望 23

5.1 全文总结 23

5.2 工作展望 24

致 谢 26

参考文献 27

第1章 绪论

1.1 引言