摘 要

目前全球能源资源大量消耗，化石能源等不可再生能源面临枯竭，柴油机的能源问题日渐严峻。虽然柴油机使用纯柴油时，动力性较高，但是它的污染问题一直也是人们关注的热点。柴油机工作时会排放出大量碳烟，这会严重污染环境，甚至是现在雾霾天气的重要诱因。所以，寻找柴油机的替代燃料成为柴油机发展的又一重大研究方向。而使用柴油混合燃料是人们研究的热点方向。

本文使用GT-power软件建立了柴油机模型，进行甲醇，乙醇和柴油混合燃料对柴油机动力性、经济性和排放性能的影响。通过甲醇燃料不变，乙醇燃料增加和乙醇燃料不变，甲醇燃料增加的对比，发现两者趋势变化几乎一致。扭矩和功率都是随着醇燃料的添加和比例增加而降低，动力性有所下降。燃油消耗率都是随醇燃料的添加和比例增加而增加，导致经济性有所下降；有效热效率是随醇燃料的添加和比例的增加而增加，经济性上升。CO排放随醇燃料的添加和比例增加而减少；NO_X排放随醇燃料的添加和比例增加而增加；碳烟排放随醇燃料的添加和比例的增加而减少。经过对比得出，当甲醇10%乙醇10%柴油80%时，动力性，经济性和排放性都比较适中。然后在这个燃料比例下调节喷油时刻，取喷油正时为-5°CA、-10°CA、-15°CA、-20°CA、-25°CA，进行发动机性能仿真。得出缸内最高压力是随喷油时刻提前而增加；功率随着喷油时刻的提前先增加后减小；燃油消耗率随喷油时刻提前先减小后增加；CO排放随喷油时刻提前先增加后减少；NO_X随喷油时刻提前而增加；碳烟排放随喷油时刻提前先增加后减少。综合而论，当喷油时刻为-15°CA时，发动机的动力性，经济性较好。而喷油时刻为-20°CA时，排放较好，尤其碳烟排放较少。

柴油机使用多元混合燃料尽管可能导致动力性和经济性有所下降，但是能有效提高排放性，尤其是大大降低了碳烟排放，这与当前节能减排的社会环境是吻合的。

关键词：甲醇；乙醇；柴油；喷油时刻；模拟仿真

Abstract

At present, a large number of global energy resources are consumed, non-renewable energy sources such as fossil energy are facing depletion, and the energy problem of diesel engines is increasingly serious. Although diesel engine has high dynamic performance when using pure diesel, its pollution has always been a hot spot of concern. Diesel engine will emit a lot of carbon smoke when working, which will seriously pollute the environment and even be an important cause of haze weather now. Therefore, finding alternative fuels for diesel engines has become another significant research direction of diesel engine development. The use of diesel fuel mixture is a hot research direction.
In this paper, GT- power software is used to establish a diesel engine model, and the influence of methanol, ethanol and diesel fuel mixture on the diesel engine's power performance, economy and emission performance is studied. Through the comparison of methanol fuel unchanged, ethanol fuel increased, ethanol fuel unchanged and methanol fuel increased, it is found that the trend changes of both are almost the same. Torque and power both decrease with the increase of alcohol fuel addition and proportion, and power performance decreases. The fuel consumption rate increases with the addition and proportion of alcohol fuel, which leads to a decline in economy. The effective thermal efficiency increases with the addition and proportion of alcohol fuel, and the economy increases. CO emission decreased with the increase of alcohol fuel addition and proportion. NO_X emission increases with the addition and proportion of alcohol fuel. Soot emission decreased with the increase of alcohol fuel addition and proportion. By comparison, when methanol 10 % ethanol 10 % diesel 80 %, the power, economy and emission are relatively moderate. Then adjust the injection timing under this fuel ratio, and take the injection timing as -5°CA、-10°CA、-15°CA、-20°CA、-25°CA, and conduct engine performance simulation. It is concluded that the maximum pressure in cylinder increases with the advance of injection time. The power first increases and then decreases with the advance of injection time. The fuel consumption rate decreases first and then increases with the injection time. CO emission increases first and then decreases with the injection timing. NO_x increases with the advance of injection timing. Soot emission increases first and then decreases with the injection timing. In general, when the injection time is - 15 °CA, the engine's dynamic performance and economy are better. When the injection time is - 20°CA, the emission is better, especially the carbon emission is less.
Although the use of multi-fuel mixture in diesel engines may reduce the power and economy, it can effectively improve the emission, especially greatly reduce the carbon emission, which is consistent with the current social environment of energy conservation and emission reduction.

Key words: methanol; Ethanol; Diesel oil; Injection timing; analog simulation

目录

摘要 I

Abstract II

目录 IV

第一章 绪论 1

1.1 选题背景 1

1.2 国内外研究现状 1

1.3 发动机仿真技术 3

1.4本文研究内容 3

第二章 模型建立与校核 5

2.1 软件介绍 5

2.2 GT-power的建模流程 5

2.3模型建立 5

2.4模型验证 6

2.5 本章小结 8

第三章 不同比例下多元燃料的动力性，经济性，排放性仿真分析 9

3.1 甲醇和乙醇燃料 9

3.1.1 甲醇燃料 9

3.1.2乙醇燃料 9

3.1.3 燃料比例的确定 10

3.2.甲醇比例不变下发动机性能分析 11

3.2.1 动力性分析 11

3.2.2 经济性分析 13

3.2.3 排放性分析 14

3.3乙醇不变情况下发动机性能分析 17

3.3.1 动力性分析 17

3.3.2 经济性分析 18

3.3.3 排放性分析 19

3.4 本章小结 21

第四章 喷油时刻对柴油机加性能的影响 22

4.1 动力性 22

4.2 经济性 23

4.3 排放性 24

4.4 本章小结 25

第五章 结论 26

5.1 本课题研究总结 26

5.2 展望 26

参考文献 28

致谢 29

第一章 绪论

1.1 选题背景

随着世界经济不断发展，传统工业水平也在不断提高，汽车行业也在迅猛发展。汽车作为传统出门代步工具，在人们的生活中占重要地位。虽然汽车对于人们日常生活的帮助很大，但是随着汽车数量的增多，随之而来的能源危机和环境污染问题也引起了广泛的关注和研究。

目前世界上化石燃料的大量开采，使得这类不可再生资源已面临枯竭的地步。预计在未来几十年世界范围内的石油等化石能源将会被开采殆尽。当人们开车出行的同时，汽车不仅在消耗着柴油等燃料，同时会排放出大量的废气如CO₂、CO、NO_X等。这些废气会对环境造成巨大的破坏。尤其是现在汽车越来越走进普通家庭，人们的人均汽车保有量也在逐渐升高。所以汽车废气排放量巨大。与此引发的全球气候问题还有雾霾，酸雨等极端天气都会对环境和人体造成巨大的伤害。因此，对于汽车的能源替换和污染防治成为汽车发展上又一个需要解决的问题。

柴油机作为传统内燃机，在世界范围内的应用是非常广泛的。柴油机具有热效率高、经济性好、动力性强还有较强的耐用性等优点。柴油机主要用于重型汽车、大型客车、工程机械、船舶、发电机组等地方，而且现在也有应用于乘用车的趋势。邵丽靑等认为柴油机行业整体发展良好，产业结构调整现象逐渐显现，随着排放标准的不断升级和外资的进入，柴油机行业的企业竞争将明显加剧，因此柴油机技术升级将会加快^[1]。但是由于柴油机的碳烟和颗粒排放较高不适应当前节能减排的社会形势，所以使用代替燃料成为推动柴油机发展的一个重要方法。