轮机英语翻译课文.docx

本文格式为Word版，下载可任意编辑轮机英语翻译课文 LESSON 1 Diesel engines The majority of ships around the world continue to be powered exclusively by diesel engines. 世界范围内大多数船舶都是采用柴油机作为动力 The predominance of diesel engines has come from improved engine efficiencies and designs compared to other forms of propulsion such as steam or gas turbines. 与蒸汽机、燃气轮机等形式的动力装置相比，无论是效率上的提高，还是设计上的进步，柴油机都表达出了确定的优势 Many combinations and configurations of diesel engine power plant exist. All provide the energy to do the work of moving the ship using diesel engines. 存在有好多种联合形式及布局形式的柴油机动力装置，他们都能够利用柴油机为船舶供给推动力。

Slow speed diesel engines 低速柴油机 Slow speed diesel engines are large, especially tall, and heavy and operate on the two-stroke cycle. 低速柴油机是体积较大、缸体较长、机身较重的二冲程柴油机 These are the largest diesel engines ever built. Engine powers up to 100 000kw are available from a single engine. 它们是已建立过的最大型的柴油机，它们的单机可用功率可达100000 kw They are tall to allow for long strokes which improve engine efficiency .the large physical allow for long strokes which improve engine efficiency. 较长的缸体能供给一个较长的冲程，有助于提高柴油机的效率。

The large physical size of the engine and components leads to slow rotational speed with speeds up to 300rpm considered to be slow. 柴油机及其部件的物理体积较大，导致其回转速度较低，尽管能够加速到300 rpm，但还是被认为是低速机 For equivalent power output, the two-stroke diesel engine is significantly lighter than its comparable four-stroke relative. 对于一致的功率输出，相对于四冲程柴油机，二冲程柴油机的重量明显轻好多 This is most apparent for large power requirements where the two-stroke engine produces much more power for the same weight. 对于大功率需求场合这是一个最明显的优势，二冲程柴油机能够在一致的重量处境下，发出更大的功率。

Large, slow speed, two-stroke marine diesel engines offer the advantages of： 大型、低速、二冲程船用柴油机的优点如下： 1. Burning poorer quality, cheaper fuel 燃烧劣质、低价的燃油 2. Providing large power from a single, less complicated machine comprising fewer individual cylinders and moving parts一个仅有几个独立汽缸和运动部件组成的、低繁杂程度的柴油机就能供给较大的功率 3. Having a low rotational speed allowing them to be directly coupled to the propeller and removing the need for transmission machinery such as clutches and gearboxes etc, 回转速度较低，能够直接和螺旋桨连接，不需要像离合器、齿轮箱等的中间传动机构。

4. Being reversible and thus eliminating the need for reversing gear or controllable pitch propellers. Merchant ships driven by slow speed diesel engine will usually have a single large main engine directly coupled to a single fixed pitch propeller. The thrust forces from the propeller will be transferred to the hull of the ship through a thrust bearing built into a thrust block, the thrust block may be built as part of the slow speed engine, and this system is supported by diesel generators providing the ship‘s electrical power. 由于能够倒转，所以就不需要换向机构和可调距螺旋桨。

利用低速柴油机驱动的商船，通常只有一台直接连到定距桨上的大型主机 Medium speed, four –stroke diesel engines 中速四冲程柴油机 Medium speed engines operate in speed ranges from 300 to 900 rpm. The majority of medium speed engines operate on the four-stroke cycle. 中速机的运转速度范围是300 —900 rpm，大多数的中速机都是四冲程柴油机 They are most common as the propulsion engines in smaller ships, ro-ro and passenger ships. They are used widely as the electrical power generation engines in most merchant cargo ships. 它们在小型船舶、滚装船舶以及客船上应用较多，在大多数的商用货船上被广泛用做发电机的原动机。

Four-stroke engines have more moving parts, are more complex and produce less power for equivalent weight compared to two-stroke slow speed engines. Medium speed engines do, however, offer several advantages which make them attractive for marine applications. 四冲程柴油机有较多的运动部件，也更加繁杂一些，跟二冲程低速柴油机相比一致的重量发出的功率较少然而，中速柴油机也有一些导致它们在船上使用的优点 1. The engines are compact----they are not long or high, this allows them to fit in engine rooms with low head space such as those in ro-ro ships. Fitted under the vehicle deck. 它们不长也不高，机型紧凑，这就使它们适合安装在空间较低的机舱当中，譬如在滚装船上，它们就安装在汽车甲板的下面。

2. Medium speed engines use less oil than slow speed engines.中速机比低速机更省油 3. Recent developments have produced medium speed engines capable of burning low quality heavy fuel oil.近年来的进展也使中速机能够燃用低质燃料油 4. Engines of considerable power, to 25,000kw and more, have been developed, allowing a large power system to be achieved with compact engines and engine room. This makes them suitable for passenger ship applications where the smaller the space provided for engines and machinery the more space is available for paying passengers. 25,000kw甚至更大功率的中速机已经被开发出来，这就使得能够利用较小体积的柴油机和较小空间的机舱达成较大的功率。

这样就适合在客船上安装使用中速机，柴油机和机械设备占用的空间较小，能够为旅客供给出更多的可用空间 Most medium-speed diesel engines are non–reversible meaning that a controllable pitch propeller is usually employed to cater for astern thrust. 大多数的中速柴油机是不成倒转的，这就意味着通常要利用变距桨实现向后的推力 Propulsion system compared to an equivalent ship with a matched slow speed propulsion system operating at optimum conditions, when used as the primary source of power for propulsion applications med。