overhead cam

简明释义

上凸轮

英英释义

例句

1.The new sports car features an advanced overhead cam engine design for better performance.

这款新跑车采用了先进的顶置凸轮轴发动机设计，以提高性能。

2.When rebuilding the engine, I opted for an overhead cam setup for improved efficiency.

在重建发动机时，我选择了顶置凸轮轴配置以提高效率。

3.The mechanic explained that the overhead cam configuration allows for more precise valve timing.

机械师解释说，顶置凸轮轴配置允许更精确的气门时机。

4.Many modern motorcycles use an overhead cam system to enhance power delivery.

许多现代摩托车使用顶置凸轮轴系统来增强动力输出。

5.The overhead cam technology has become standard in most new vehicles today.

如今，顶置凸轮轴技术已成为大多数新车的标准配置。

作文

The term overhead cam refers to a design feature in internal combustion engines where the camshaft is located above the cylinder head. This configuration allows for more efficient operation of the engine by enabling better airflow and timing of the engine's valves. The overhead cam design has become increasingly popular in modern automotive engineering due to its advantages over traditional camshaft designs. One of the primary benefits of an overhead cam setup is that it reduces the number of components needed in the engine, which can lead to a lighter and more compact engine overall.In an engine with a traditional camshaft located in the block, the camshaft must use pushrods and rocker arms to operate the valves. This adds weight and complexity to the engine. In contrast, an overhead cam engine can directly actuate the valves, resulting in a more straightforward and efficient design. Additionally, because the camshaft is positioned closer to the valves, it can provide more precise timing and control over valve lift, which enhances performance and efficiency.There are two main types of overhead cam configurations: single overhead cam (SOHC) and double overhead cam (DOHC). A SOHC engine has one camshaft per cylinder bank, while a DOHC engine has two camshafts per bank—one for intake valves and another for exhaust valves. The DOHC configuration allows for even greater control over the engine’s performance, as it can optimize the timing of both intake and exhaust events independently. This results in increased power output and better fuel efficiency, making DOHC engines highly desirable in high-performance vehicles.Moreover, the overhead cam design contributes to higher engine speeds and improved throttle response. Because the camshaft operates at half the speed of the crankshaft, it can be designed to have more aggressive profiles that enhance performance at higher RPMs. This is particularly beneficial in sports cars and racing applications, where every bit of power matters. The ability to rev higher without sacrificing reliability is a significant advantage that many manufacturers leverage when designing their performance-oriented engines.Another important aspect of overhead cam engines is their impact on emissions and fuel economy. With better control over valve timing and lift, these engines can achieve more complete combustion of the air-fuel mixture, leading to lower emissions. As environmental regulations become stricter, the efficiency of overhead cam designs makes them increasingly attractive to automakers looking to meet these standards while still delivering performance.In summary, the overhead cam design is a crucial innovation in automotive engineering that has transformed how we think about engine performance. By placing the camshaft above the cylinder head, engineers have created a more efficient, powerful, and environmentally friendly engine configuration. Whether in everyday vehicles or high-performance sports cars, the overhead cam technology continues to play a vital role in the evolution of modern engines. As we look to the future, it is clear that the principles behind overhead cam designs will remain central to advancements in automotive technology, pushing the boundaries of what is possible in engine performance and efficiency.

短语overhead cam指的是内燃机中的一种设计特征，其中凸轮轴位于气缸头上方。这种配置通过改善空气流动和发动机阀门的定时，使发动机的运行更加高效。由于其相对于传统凸轮轴设计的优势，overhead cam设计在现代汽车工程中变得越来越流行。overhead cam设置的主要好处之一是减少发动机所需的组件数量，这可以导致整体更轻、更紧凑的发动机。在传统凸轮轴位于机体的发动机中，凸轮轴必须使用推杆和摇臂来操作阀门。这增加了发动机的重量和复杂性。相比之下，overhead cam发动机可以直接驱动阀门，从而实现更简单和高效的设计。此外，由于凸轮轴靠近阀门，它可以提供更精确的定时和对阀门升程的控制，从而增强性能和效率。overhead cam配置有两种主要类型：单顶置凸轮（SOHC）和双顶置凸轮（DOHC）。SOHC发动机每个气缸组有一个凸轮轴，而DOHC发动机每个气缸组有两个凸轮轴——一个用于进气阀，另一个用于排气阀。DOHC配置允许对发动机性能进行更大的控制，因为它可以独立优化进气和排气事件的定时。这导致功率输出增加和燃油效率提高，使DOHC发动机在高性能车辆中非常受欢迎。此外，overhead cam设计有助于提高发动机转速和改善油门响应。由于凸轮轴以曲轴的一半速度运行，因此可以设计出更具攻击性的轮廓，以增强高转速下的性能。这在跑车和赛车应用中尤其有利，因为每一点动力都至关重要。能够在不牺牲可靠性的情况下提高转速是许多制造商在设计其高性能发动机时利用的重要优势。overhead cam发动机的另一个重要方面是它们对排放和燃油经济性的影响。通过更好地控制阀门的定时和升程，这些发动机可以实现更完全的空气-燃料混合物燃烧，从而降低排放。随着环境法规变得越来越严格，overhead cam设计的效率使其对希望满足这些标准的汽车制造商变得越来越有吸引力，同时仍能提供性能。总之，overhead cam设计是汽车工程中的一项关键创新，改变了我们对发动机性能的看法。通过将凸轮轴放置在气缸头上方，工程师创造了一种更高效、更强大且更环保的发动机配置。无论是在日常车辆还是高性能跑车中，overhead cam技术继续在现代发动机的演变中发挥着重要作用。展望未来，显然，overhead cam设计背后的原则将继续在汽车技术的进步中占据核心地位，推动发动机性能和效率的可能性边界。