Basic Engine Parts
发动机的基础零件
The core of the engine is the cylinder, with the piston moving up and down inside the cylinder. The engine described above has one cylinder. That is typical of most lawn mowers, but most cars have more than one cylinder (four, six and eight cylinders are common). In a multi-cylinder engine, the cylinders usually are arranged in one of three ways: inline, V or flat (also known as horizontally opposed or boxer), as shown in the following figures.
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发动机的核心是气缸，活塞在气缸内上下运动。以上所说的是单气缸发动机。多数草坪割草机都只有一个气缸，但多数车辆的发动机却不止一个气缸（常见的有 4气缸、6 气缸以及 8 气缸）。多气缸发动机的气缸排列方式通常分 3 种：直列式，V 型或水平对卧式（又称为水平対置式或対置式），如下图所示。
Different configurations have different advantages and disadvantages in terms of smoothness, manufacturing cost and shape characteristics. These advantages and disadvantages make them more suitable for certain vehicles.
就其平稳性、生产成本及外形特征而言，气缸的不同配置方式各有利弊，造就了某些车辆的个性化特征。
Let's look at some key engine parts in more detail.
让我们仔细了解一下发动机的部分关键零件。
Spark plug 火花塞
The spark plug supplies the spark that ignites the air/fuel mixture so that combustion can occur. The spark must happen at just the right moment for things to work properly.
火花塞产生火花，点燃空气 / 燃料混合气，从而发生燃烧。火花必须在适当的时刻产生，这样才能确保所有工作有序进行。
Valves 气门
The intake and exhaust valves open at the proper time to let in air and fuel and to let out exhaust. Note that both valves are closed during compression and combustion so that the combustion chamber is sealed.
进气门与排气门在适当的时间打开，以便吸入空气与燃料，排出废气。需注意的是在压缩与燃烧过程中，进气门与排气门处于关闭状态，以确保燃烧室的密封性。
Piston 活塞
A piston is a cylindrical piece of metal that moves up and down inside the cylinder.
活塞是圆柱形金属块，在气缸内上下运动。
Piston rings 活塞环
Piston rings provide a sliding seal between the outer edge of the piston and the inner edge of the cylinder. The rings serve two purposes:
活塞环确保活塞外边缘与气缸内边缘之间的滑动密封。活塞环的作用有 2 个：
They prevent the fuel/air mixture and exhaust in the combustion chamber from leaking into the sump during compression and combustion.
防止燃烧室内的燃料 / 空气混合气以及废气在压缩与燃烧过程中漏到油底壳。
They keep oil in the sump from leaking into the combustion area, where it would be burned and lost.
同时防止油底壳内的机油进入燃烧区域，造成机油燃烧和损失。
Most cars that "burn oil" and have to have a quart added every 1,000 miles are burning it because the engine is old and the rings no longer seal things properly.
多数汽车之所以“烧机油”，每行驶 1000 英里必须添加一夸脱机油，是因为发动机老化，活塞环封闭性变差。
Connecting rod 连杆
The connecting rod connects the piston to the crankshaft. It can rotate at both ends so that its angle can change as the piston moves and the crankshaft rotates.
连杆连接活塞与曲轴。两端均可旋转，因此活塞运动及曲轴旋转时连杆角度发生变化。
Crankshaft 曲轴
The crankshaft turns the piston's up and down motion into circular motion just like a crank on a jack-in-the-box does.
曲轴将活塞的上下运动转换为圆周运动，原理类似于玩偶盒的摇把。
Sump 油底壳
The sump surrounds the crankshaft. It contains some amount of oil, which collects in the bottom of the sump (the oil pan).
油底壳包围着曲轴，存储部分机油，机油集中在油底壳（机油盘）底部。
Inline - The cylinders are arranged in a line in a single bank
直列式 – 气缸单列直线布置
V - The cylinders are arranged in two banks set at an angle to one another
V 型 – 气缸以一定角度分两列布置
Flat - The cylinders are arranged in two banks on opposite sides of the engine.
水平对卧式 – 气缸分两列布置在发动机两侧
