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，柴油机都体现出了一定的优势。 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. 存在有很多种联合形式及结构形式的柴油机动力装置，他们都能够利用柴油机为船舶提供推动力。 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. 它们是已建造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. 较长的缸体能提供一个较长的冲程，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. 对于相同的功率输出，相对于四冲程柴油机，二冲程柴油机的重量明显轻很多。 This is most apparent for large power requirements where the two-stroke engine produces much more power for the same wei...
