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Anti-ice Posted by Ari [Email] (#2847) [Profile/Gallery] (more from Ari) on Tue, 1 May 2001 16:25:04 In Reply to: Would this work?, nickR, Mon, 30 Apr 2001 22:36:28 Members do not see ads below this line. - Help Keep This Site Online - Signup |
The purpose of the heated coolant is to provide throttle de-icing. Icing conditions can happen WELL above freezing - ask any private pilot.
Your air conditioner works by compressing a fluid (Freon of one form or another). This creates lots of heat that is pushed out through a radiator. Then this compressed fluid is released through an expansion valve, which is basically just a hole into a large volume. When the fluid expands, it gets VERY cold. That's how you can make 100 degree air into 32 degree air with no problem.
Now, think about a throttle body. At low throttle openings, you've got a small hole (almost closed throttle plate) and a big open space beyond (throttle body). Physics is physics, so you get a cooling effect. On a nice, warm and humid day, that air has lots of water in it. You can get a lot of cooling, and you can form ice in the throttle body. This restricts flow, which means more vacuum, which ends up as more expansion, and more cold, and more ice. Plenty of small planes have crashed on nice hot summer days because the pilot forgot the carb de-ice.
Not much of an effect at wide open throttle conditions, but it's sure there at partial throttle. And just cruising down the highway, or going downhill, and at idle, you have an almost closed throttle plate.
Yes, this adds a little heat to the intake charge, but not a whole lot. Throttle icing is much worse.
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