汽车技术类 长刊栏目 英译中

six-cylinder diesel engine

6 缸柴油发动机

One big difference between a diesel engine and a gas engine is in the injection process. Most car engines use port injection or a carburetor. A port injection system injects fuel just prior to the intake stroke (outside the cylinder). A carburetor mixes air and fuel long before the air enters the cylinder. In a car engine, therefore, all of the fuel is loaded into the cylinder during the intake stroke and then compressed. The compression of the fuel/air mixture limits the compression ratio of the engine -- if it compresses the air too much, the fuel/air mixture spontaneously ignites and causes knocking. Because it causes excessive heat, knocking can damage the engine.

柴油发动机与汽油发动机的一个很大区别在于喷射过程。大多数汽车发动机采用进气管喷射或化油器。进气管喷射系统在进气冲程之前的适当时刻喷射燃油（气缸之外）。早在空气进入气缸之前化油器将空气与燃油混合。因此汽车发动机的全部燃油在进气冲程期间进入气缸，然后进行压缩。燃油/空气混合气的压缩压力决定发动机的压缩比 – 如果压缩压力过大，则会造成温度过高，从而自动点燃燃油/空气混合气并引起爆震，爆震则可能损坏汽车发动机。

Diesel engines use direct fuel injection -- the diesel fuel is injected directly into the cylinder.

柴油发动机采用燃油缸内直喷 – 柴油直接喷入气缸。

The injector on a diesel engine is its most complex component and has been the subject of a great deal of experimentation -- in any particular engine, it may be located in a variety of places. The injector has to be able to withstand the temperature and pressure inside the cylinder and still deliver the fuel in a fine mist. Getting the mist circulated in the cylinder so that it is evenly distributed is also a problem, so some diesel engines employ special induction valves, pre-combustion chambers or other devices to swirl the air in the combustion chamber or otherwise improve the ignition and combustion process.

柴油发动机所使用的喷油器是其最复杂的组件，经过了大量的试验验证 – 发动机不同，喷油器的安装位置也可能不同。喷油器必须能承受气缸内的温度与压力，同时仍能以喷雾的形式输送燃油。要使燃油喷雾在气缸内循环，均匀分布很重要，因此一些柴油发动机使用特殊的进气门、预燃室或其它设备，以使空气呈漩涡状进入燃烧室或改善点火与燃烧过程。

Some diesel engines contain a glow plug. When a diesel engine is cold, the compression process may not raise the air to a high enough temperature to ignite the fuel. The glow plug is an electrically heated wire that heats the combustion chambers and raises the air temperature when the engine is cold so that the engine can start.

某些柴油发动机有预热塞。当柴油发动机处于冷态时，压缩过程中空气温度可能不足以点燃燃油。预热塞是一种电热丝，可在发动机处于冷态时加热燃烧室，同时提升空气温度，从而能够起动发动机。

All functions in a modern engine are controlled by the ECM communicating with an elaborate set of sensors measuring everything from R.P.M. to engine coolant and oil temperatures and even engine position. Glow plugs are rarely used today on larger engines. The ECM senses ambient air temperature and retards the timing of the engine in cold weather so the injector sprays the fuel at a later time. The air in the cylinder is compressed more, creating more heat, which aids in starting.

现代发动机的所有功能都由 ECM 控制。ECM 可与一组精心设计的传感器通信，这些传感器可测量发动机转速、冷却液温度、机油温度和发动机位置等信息。现在大型发动机上很少使用预热塞。ECM 探测环境空气温度，在低温环境下推迟发动机正时，因此延迟一段时间后喷油器喷射燃油。气缸内的空气压缩压力越大，产生的热量就越多，热量有助于起动发动机。

Smaller engines and engines that do not have such advanced computer control use glow plugs to solve the cold-starting problem.

小型发动机和非电控发动机使用预热塞解决发动机冷起动问题。

Of course, mechanics aren't the only difference between diesel engines and gasoline engines. There's also the issue of the fuel itself.

当然，机械机构并非是柴油发动机和汽油发动机的唯一区别。这也与燃油本身有关系。

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