top dead center

简明释义

上止点

英英释义

例句

1.The mechanic explained that the valves should open just after top dead center.

机械师解释说，阀门应该在上止点后立即打开。

2.During the compression stroke, the engine will compress the air until it reaches top dead center.

在压缩行程中，发动机会压缩空气，直到达到上止点。

3.Ensure that the crankshaft is positioned at top dead center before installing the timing belt.

在安装正时皮带之前，确保曲轴处于上止点位置。

4.The piston reaches top dead center when it is at its highest point in the cylinder.

活塞在气缸中达到上止点时，处于其最高点。

5.To set the ignition timing, you need to align the marks at top dead center.

要设置点火时机，您需要在上止点对齐标记。

作文

In the world of internal combustion engines, the term top dead center refers to a critical position in the engine's cycle. Specifically, it is the point at which the piston is at its highest position within the cylinder, and the volume above the piston is minimized. This position is crucial for several reasons, particularly in the context of engine performance and efficiency. Understanding the significance of top dead center can help both automotive enthusiasts and engineers optimize engine designs and improve overall functionality.When an engine is running, it undergoes a continuous cycle of intake, compression, power, and exhaust strokes. The top dead center is reached at the end of the compression stroke, just before the spark plug ignites the air-fuel mixture. This ignition occurs precisely at this point to ensure maximum efficiency and power output. If the ignition timing is too early or too late relative to the top dead center, it can lead to knocking, reduced power, and increased emissions. Thus, achieving the correct timing is essential for optimal engine performance.Moreover, the top dead center position also plays a vital role in determining the engine's compression ratio. The compression ratio is the ratio of the cylinder's maximum volume to its minimum volume, which directly influences the engine's power and efficiency. A higher compression ratio typically allows for more power generation from the same amount of fuel, but it also requires precise control of the ignition timing to avoid knocking. Therefore, understanding the relationship between the compression ratio and top dead center is crucial for engineers designing high-performance engines.Another important aspect related to top dead center is valve timing. In an internal combustion engine, the opening and closing of the intake and exhaust valves must be synchronized with the piston's movement. The timing of these events is often measured in relation to the top dead center. For instance, the intake valve might open slightly before the piston reaches top dead center to allow for better airflow into the cylinder, enhancing the engine's performance. Engineers use camshafts and timing belts to ensure that these components work together effectively.In summary, the concept of top dead center is fundamental to understanding how internal combustion engines operate. It affects ignition timing, compression ratios, and valve timing, all of which are critical for maximizing engine performance and efficiency. As automotive technology continues to evolve, the importance of optimizing these parameters around the top dead center position will remain paramount. For anyone interested in the mechanics of engines, mastering the implications of top dead center is essential for both practical applications and theoretical understanding. By grasping this concept, one can appreciate the intricate workings of engines and contribute to advancements in automotive engineering.

在内燃发动机的世界中，术语上死点指的是发动机循环中的一个关键位置。具体来说，它是活塞在气缸内达到最高位置时的状态，此时活塞上方的体积最小。这个位置对于多个原因至关重要，特别是在发动机性能和效率的背景下。理解上死点的重要性可以帮助汽车爱好者和工程师优化发动机设计，提高整体功能。当发动机运转时，它会经历进气、压缩、动力和排气冲程的连续循环。上死点在压缩冲程结束时达到，正好在火花塞点燃空气-燃料混合物之前。这个点的点火发生得非常准确，以确保最大效率和功率输出。如果点火时机相对于上死点过早或过晚，可能会导致敲击、功率降低和排放增加。因此，达到正确的时机对于优化发动机性能至关重要。此外，上死点位置在决定发动机的压缩比方面也发挥着重要作用。压缩比是气缸最大体积与最小体积的比率，直接影响发动机的功率和效率。较高的压缩比通常允许在相同数量的燃料中产生更多的功率，但它也需要精确控制点火时机以避免敲击。因此，理解压缩比与上死点之间的关系对于设计高性能发动机的工程师至关重要。与上死点相关的另一个重要方面是气门时机。在内燃发动机中，进气和排气气门的开启和关闭必须与活塞的运动同步。这些事件的时机通常是相对于上死点来测量的。例如，进气气门可能在活塞到达上死点之前稍微提前开启，以增强气流进入气缸，从而提高发动机性能。工程师使用凸轮轴和时序带来确保这些组件有效配合工作。总之，上死点的概念是理解内燃发动机如何工作的基础。它影响点火时机、压缩比和气门时机，所有这些都是最大限度提高发动机性能和效率的关键。随着汽车技术的不断发展，围绕上死点位置优化这些参数的重要性将始终存在。对于任何对发动机机械感兴趣的人来说，掌握上死点的含义对于实际应用和理论理解都是必不可少的。通过掌握这个概念，人们可以欣赏到发动机复杂的工作原理，并为汽车工程的进步做出贡献。