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Air conditioning 汽车空调
Part 4:Leak detection 第4部分：泄漏检测
Leak detection is not only a potentially time consuming activity but it can also put us on the wrong side of the law. The refrigerant used in Mobile Air Conditioning systems (MAC) is a compound of Hydrogen Fluorine and Carbon (HFC) and is subject to some increasingly tight controls.
泄漏检测不仅会是个可能很耗时的过程，同样会把我们推到违法的位置。汽车空调（英文简称MAC）系统中使用的制冷剂是本英语毕业论文由英语论文网 www.51lunwen.org整理提供
一个氢氟和氮（英文简称HFC）的混合物，它的使用逐渐受到严格的控制。
Older readers will remember vehicles fitted with the “old gas” called R12, a compound of Chlorine, Fluorine and Carbon (CFC). It was developed in the 1930s as a safe refrigerant. Safe in that up until then, a leak from a fridge could either cause an explosion or send you into a peaceful sleep from which you may never wake. Then it was found to be damaging the earth’s Ozone layer and was replaced in cars in 1994 by R134a.
年长的读者们会记得有些车辆注入的“元老级气态制冷剂”为R12，一种氯氟碳（英文简称CFC）的混合物。它作为一种安全的制冷剂在20世纪30年代被开发出来。直到那时，它还是安全的。一个冰箱的一次泄漏可能会导致一次爆炸或使你安详入睡，不再醒来。之后人们发现它会破坏地球的臭氧层。1994年时，汽车中的制冷剂被替换为R134a。
But in a further twist R134a was also found to be environmentally harmful and is due to be phased out. Meanwhile, there are strict regulations governing its use.
但是又一个反转，人们发现R134对环境也是有害的，即将停止它的使用。同时，严格的规定也监管它的使用。
But back to leak detection. 回归正题，泄漏检测。
The leaking could come from anywhere in the system, from tubing to an accumulator to a tiny pressure switch gone bad. Customers generally don’t report leaks. They only report an inefficient or inoperative system.
泄漏可能源自系统的任何地方，如管道，累加器，还有坏掉的一个小压力开关。顾客们通常不会称出现泄露的毛病，通常只会说系统功效不足或不运行。

Ultra-Violet Detection 紫外线检测
UV dye is injected into the system, mixing with the lubricant and the liquid refrigerant. When a refrigerant leak occurs, the dye comes out with it and leaves a stain around the point of exit. This makes detection remarkably easy as long as the leak is somewhere that can be seen. You will need a UV lamp, the brighter the better, and some UV glasses. The effects are quite remarkable.
紫外线（英文简称UV）着色剂是注入到系统里的，同润滑油和液态制冷剂混合。制冷剂泄漏的话，着色剂就会随之流出，在泄漏点附近留下颜色痕迹。因此，只要泄漏发生在可见的位置，那么检测过程就变得相当简单。你将需要一个紫外线灯，越亮越好，还有一些紫外线眼镜。效果相当明显。
This of course relies on there being UV dye in the system when the leak occurs so it is in your interest to make sure there is. Look at the service valves with the UV glasses and lamp and you should see it. Any recovered PAG oil will have a luminescent glow to it but, if you are unsure, put some in!
这当然是因为在系统中有紫外线着色剂。当泄漏发生时，要确保系统中存在UV着色剂。利用UV眼镜和灯观察服务阀，你应该会发现它。任何回收的PAG油会使泄漏的液体发出荧光，如果你不确定的话，放一些PAG油进去好啦！
It is normally introduced by injecting 5-10ml into the low pressure side when the engine is running and the AC working. It can be a messy affair and the kit should contain some remover. Always clean any spills as this could confuse any later diagnosis. You can also buy the refrigerant with the dye in it so it goes into every vehicle you service. Some recycling machines have the option of automatic dye injection which is very handy.
正常情况下，当引擎在工作或AC系统运行时，推荐在低压端注入5-10毫升。这个活是个脏活，所以套箱里应该包含一些去除剂。清理任何溢出物，因为它会迷惑所有后面的诊断。你还可以购买注有着色剂的制冷剂，这样它就可以被注入你服务的每辆机动车系统中。有些循环使用的机器中可以选择自动注入着色剂，因为它非常方便。
No Gas Pressure? 没有气压？

Remember the mantra “deliberate release of refrigerant is banned”, so putting in a couple of hundred grams of refrigerant into the system and seeing if it comes out could see you with a hefty fine. If the system is empty or of such a low pressure (i.e. less than 2 bars at a