调速器外文翻译@中英文翻译@外文文献翻译

调速器 调速器的作用是将内燃机的转速限制在一定范围内。运行时，柴油机所带的负载是不断变化的。在负载变化时，特别是突然变化时，必须保持柴油机的转速稳定，不得出现停车或飞车事故。调速器就是自动保持转速稳定的装置。对于发电用的柴油机，要求其转速基本恒定在同步转速，对调速器的调速特性要求很高。 内燃机工作时，如内燃机的输出转矩与外界的阻力矩 (负载 )相等时，工作才能稳定。如阻力矩超过内燃机的转矩时，转速将降低 ；反之则升高。为使工作机械稳定地工作，就必须随着阻力的变化相应调节供油量，使发动机的转矩与外界负 载相适应。由柴油机的速度特性可以看出，柴油机的转矩 Me=f(n)曲线比较平坦。在柴油机运转时，如油量调节杆固定在某一位置，柴油机的转矩 Me 就按速度特性变化，而外界负载是经常变化的。如推土机在干湿不同、软硬不一的土壤中作业时，阻力矩就有明显的变化。如阻力矩有较小的变化 ( M)，将引起转速较大的变化 ( n)，柴油机的工作是不稳定的。如要人为的控制供油量来适应外界负载的变化，这不仅使司机疲劳，而且也难以保持转速的稳定。 调速器属于自动调节装置。当外界负载变化时，它能随着负载的变化自动调节供油量，使柴 油机的转速稳定在一定的转速范围内。 汽车或工程机械是经常在负载不断变化的情况下工作的，而且还会遇到负载突变的情况。如推土机作业时，当卸土以后，由于突然卸去了负载，喷油泵油量调节杆一时还来不及向减少供油量的方向移动，柴油机的转速就会迅速升高，而这时由于喷油泵速度特性的作用，喷油泵的循环供油量反而增大，促使柴油机的转速进一步升高。这样相互影响的结果，便柴油机的转速越来越高，严重时会出现超速，甚至发生 飞车 事故，以致引起机件损坏。 另外，柴油机还经常遇到低速空转 (怠速 )的场合，如短暂 停车、起动暖车、变速器换挡等。柴油机在怠速运转时只供给很少量的燃油，这部分燃油发出的能量只能克服发动机内部的摩擦阻力，这时发动机工作的稳定性主要取决于其内部摩擦阻力的变化和气缸内气体做功变化的相互关系。这两者可用平均机械损失压力 Pm 和平均指示压力 Pi 的变化来表示。一般发动机随转速的增加，平均机械损失压力 Pm 都略有增加。为了使怠速运转稳定，必须在转速升高时，使平均指示压力 Pi 减小，而在转速降低时使其增大。柴油机怠速运转时，油量调节杆保持在最小供油量位置，这时如果某种原因 (如润滑油粘度的变化 )使柴油机的内部阻力 略有增大，则其转速就略为降低，但由于喷油泵速度特性的作用，每循环供油量反而减少，这就促使转速迸一步降低，如此循环作用，最后将使柴油机熄火 ；反之，如柴油机内部的阻力略有减小，则将导致柴油机怠速转速不断升高，所以柴油机的怠速是很不稳定的。因此，汽车柴油机通常装用两极式调速器来达到防止超速和稳定怠速的目的。 调速器的作用即在于改变 Pi 曲线的变化历程，使 Pi 曲线随转速升高而急剧下降。这样在怠速时能保持稳定，在高速时能防止超速。 在某些工作条件比较特殊的柴油机上，如工作时负载变化急剧的工程 机械以及工作条件要求在负载改变后转速保持一定范围的柴油机 (如带发电机、空压机、水泵等 )，则要求采用全程式调速器，这种调速器不仅能防止超速和保持怠速的稳定性，而且还能自动控制任何所要求的速度工况。全程式调速器还可以减轻司机操作，提高柴油机的使用经济性和劳动生产率。 2.柱塞式喷油泵的速度特性。喷油泵的循环供油量主要取决于油量调节杆 (拉杆或齿杆 )的位置。但是，在实际上供油量还受到柴油机转速的影响。 当油量调节杆位置定时，喷油泵的循环供油量随转速变化的关系，称为喷油泵的速度特性。它对柴 油机的工作有很大的影响。 Governor The role of governor is to limit the engine speed within a certain range. Running, engine load is carried by the ever-changing. When the load changes, especially sudden changes, the need to maintain the engine speed stability, with no parking or coaster accident. Governor is a device that automatically maintains speed stability. Diesel engines for power generation, asking them to speed almost constant in the synchronous speed, the speed characteristics of the governor demanding. Internal combustion engines work, such as the internal combustion engine output torque and the external resistance moment (load) are equal, working to stabilize. Such as the drag torque than internal combustion engine torque, the speed will be reduced； otherwise increased. Mechanical stability for the work to work, to be adjusted accordingly with the change of resistance of fuel supply, engine torque load with the outside world to adapt. The speed of the engine characteristics can be seen, the engine torque Me = f (n) curve is flat. In the diesel engine operation, such as the oil lever in a fixed position, engine speed torque characteristics by Me to change, while the external load is constantly changing. Such as bulldozers in the different wet and dry, hard and soft soil in different operations, there are significant changes in resistance torque. If there are small changes in resistance torque ( M), will cause a large speed change ( n), the diesel engine was unstable. To control the fuel supply to artificially adapt to load changes, which not only allows the driver fatigue, but also difficult to maintain speed and stability. Governor of automatic adjustment device. When the external load changes, it can automatically adjust with the change of the load amount of oil that the engine speed steady at a certain speed range. Vehicle or machinery is often the case load changing work, but also the situation encountered mutation load. Such as the bulldozer operation, when the dump, because of the sudden load lifted, fuel injection pump lever for a moment too late to move to reduce the amount of oil, the engine speed will rapidly increase, and then the fuel pump The role of velocity characteristics, but the amount of fuel injection pump oil increases circulation to promote the engine speed further increases. The results of this interaction, increasing the engine speed will be high speed in severe cases, or even speed accident, resulting in mechanical damage. In addition, low-speed diesel engine idling also frequently encountered (idle) of occasions, such as short-term parking, starting warm up, gear shift and so on. Diesel engine running at idle only a small amount of fuel supply, this part of the fuel energy can only be issued by the friction inside the engine to overcome, then the stability of the engine depends largely on the work of the internal friction changes and changes in cylinder acting relationship. These two losses can mean mechanical pressure Pm and the average indicated pressure Pi of the changes said. General engine with engine speed increases, the mean pressure Pm mechanical losses are slightly increased. In order to idle stability to speed increases, the mean indicated pressure Pi decreases, while it increases when the speed is reduced. Diesel engine idling, fuel lever position to a minimum fuel supply, then if for some reason (such as changes in lubricant viscosity) the engines internal resistance increases slightly, its speed to slightly lower, but The role of the pump velocity characteristic, however, reduced amount of oil per cycle, which led into further reduce the speed, so cycles, the final engine will turn off； the other hand, such as diesel internal resistance decreases slightly, it will lead to engine Idle speed constantly increases, so the engine idle speed is very unstable. Therefore, the car engine is usually equipped with bipolar prevent the governor to achieve the purpose of speeding and idling stability. The role of governor is to change the course of Pi curves, so that Pi curve rises sharply with speed. This can keep the idle stable at high speed to prevent speeding. Comparison of working conditions in certain special diesel engines, such as rapid changes in work load and working conditions of construction machinery after the change in load required to maintain a certain range of engine speed (such as generator, air compressor, water pump, etc.), they are required governor with the whole program, this governor can not only prevent the i