bottom dead centre

简明释义

下死点

英英释义

例句

1.To ensure proper timing, the mechanic adjusted the ignition system to fire just after bottom dead centre.

为了确保正确的时机，机械师调整了点火系统，使其在下死点后点火。

2.The engine's efficiency can be affected by how quickly it moves past bottom dead centre.

发动机的效率可能会受到它通过下死点的速度影响。

3.When the crankshaft rotates, the connecting rod moves the piston to bottom dead centre.

当曲轴旋转时，连杆将活塞移动到下死点。

4.The piston reaches bottom dead centre when it is at its lowest point in the cylinder.

活塞在气缸中处于最低点时达到下死点。

5.In an internal combustion engine, the fuel injection occurs just before the piston hits bottom dead centre.

在内燃机中，燃油喷射发生在活塞撞击下死点之前。

作文

In the world of engineering and mechanics, certain terms hold significant importance due to their specific meanings and applications. One such term is bottom dead centre, which refers to a crucial position in the operation of engines, particularly in internal combustion engines. Understanding this term is essential for anyone working with or studying engine mechanics, as it plays a vital role in the overall functioning of the engine.To explain further, bottom dead centre (often abbreviated as BDC) is defined as the lowest point that a piston reaches within a cylinder during its stroke. This position is critical because it marks the end of the piston's downward movement and the beginning of its upward movement. In simpler terms, when the piston is at bottom dead centre, it has completed its downward journey and is ready to start moving back up. This transition is vital for the engine's cycle, as it directly affects the intake and exhaust phases of the combustion process.The significance of bottom dead centre can be observed in various aspects of engine performance. For instance, the timing of valve openings and closings is closely related to the piston's position. If the valves do not operate correctly in relation to the piston's movement, it can lead to inefficient combustion, loss of power, or even engine failure. Therefore, engineers must carefully consider the relationship between the piston's position and the timing of these critical components.Moreover, the concept of bottom dead centre is also important when it comes to engine tuning and performance optimization. By understanding the precise moment when the piston reaches this position, engineers can make adjustments to improve the efficiency and power output of the engine. This knowledge allows for better fuel-air mixture control, which is essential for maximizing performance and minimizing emissions.In addition to its mechanical significance, bottom dead centre serves as a reference point for measuring other important parameters within the engine. For example, the distance from bottom dead centre to the top dead centre (TDC), which is the highest point the piston reaches, is known as the stroke length. This measurement is crucial for determining the engine's displacement and overall capacity. A larger stroke length generally indicates a more powerful engine, as it allows for greater air-fuel mixture intake and combustion force.Furthermore, understanding bottom dead centre can aid in diagnostics and troubleshooting. When an engine exhibits problems, such as misfiring or reduced power, technicians often refer to the piston's position to identify potential issues. By analyzing the behavior of the piston in relation to bottom dead centre, they can pinpoint areas that may require repair or adjustment.In conclusion, the term bottom dead centre is more than just a technical phrase; it encapsulates a fundamental aspect of engine mechanics that has far-reaching implications for performance, efficiency, and reliability. Whether one is a student of engineering, a professional mechanic, or simply an enthusiast, grasping the concept of bottom dead centre is essential for a deeper understanding of how engines operate. As technology continues to evolve, the principles surrounding bottom dead centre will remain relevant, guiding advancements in engine design and performance optimization. Thus, it is imperative to appreciate and master this term for anyone involved in the field of automotive engineering and mechanics.

在工程和机械的世界中，某些术语因其特定的含义和应用而具有重要意义。其中一个术语是底死点，它指的是发动机，特别是内燃机运行中的一个关键位置。理解这个术语对于任何与发动机机械相关的人来说都是至关重要的，因为它在发动机的整体功能中发挥着重要作用。进一步解释，底死点（通常缩写为BDC）被定义为活塞在气缸内行程中达到的最低点。这个位置至关重要，因为它标志着活塞向下运动的结束和向上运动的开始。简单来说，当活塞处于底死点时，它已经完成了向下的旅程，并准备开始向上移动。这一过渡对于发动机的循环至关重要，因为它直接影响到燃烧过程的进气和排气阶段。底死点的重要性可以在发动机性能的各个方面观察到。例如，阀门的开启和关闭时机与活塞的位置密切相关。如果阀门未能正确地与活塞的运动相协调，可能会导致燃烧效率低下、动力损失，甚至发动机故障。因此，工程师必须仔细考虑活塞位置与这些关键部件的时机之间的关系。此外，底死点的概念在发动机调校和性能优化中也很重要。通过理解活塞达到该位置的确切时刻，工程师可以进行调整以提高发动机的效率和功率输出。这一知识使得更好的燃油-空气混合控制成为可能，这对最大化性能和最小化排放至关重要。除了机械意义外，底死点还作为测量发动机内其他重要参数的参考点。例如，从底死点到顶死点（TDC）的距离，即活塞达到的最高点，被称为行程长度。这个测量对于确定发动机的排量和整体容量至关重要。较大的行程长度通常表示更强大的发动机，因为它允许更多的空气-燃料混合物的吸入和燃烧力。此外，理解底死点有助于诊断和故障排除。当发动机出现问题，例如失火或动力降低时，技术人员通常会参考活塞的位置来识别潜在问题。通过分析活塞相对于底死点的行为，他们可以找出可能需要修理或调整的地方。总之，术语底死点不仅仅是一个技术短语；它概括了发动机机械学的一个基本方面，对性能、效率和可靠性有着深远的影响。无论是工程学生、专业机械师还是单纯的爱好者，掌握底死点的概念对于深入理解发动机的工作原理至关重要。随着技术的不断发展，围绕底死点的原则将继续保持相关性，引导发动机设计和性能优化的进步。因此，对于任何参与汽车工程和机械领域的人来说，理解和掌握这一术语是非常重要的。