Quote:
Originally Posted by ConnClark
Air temp isn't the problem. Its mainly fuel temp. Below a certain temp the fuel doesn't atomize or have the vapor pressure to emit vapors to ignite. Glow plugs add heat to the combustion chamber right next to the injectors. This heats the fuel some and adds heat to the combustion chamber walls so it doesn't sap heat away from the compressed air.
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This is true - diesels will run at almost any air temperature but the fuel temperature in the combustion chamber at start-up is critical. Almost all vehicles at the South Pole are diesel and they run all winter using a heavily winterized diesel fuel called AN-8 (Antarctic JP8). When it is -70F or below they don't take the vehicles outside because the vehicles themselves tend to break, but the engines will run at those temperatures. They would never
start at those temps, but they will run at them.
I just spent the past ten months in Antarctica during the winter, and an interesting observation is that you cannot smell diesel fuel when it is really cold (-50 to -100F) even if you spill it on yourself. It has almost no vapor pressure at those temperatures. As soon as you go back into a heated area you will reek of diesel, but you can stick your nose over an open diesel tank in the cold and you won't smell a thing.