How much gas does a car use when idling?
I drive in a lot of isolated areas and sometimes need to take a break in a rest area, for a nap, to read, or do some paper work. How much gas would a 4 cylinder car use in a half hour if I let the engine run with the AC on? It is too darn hot here in Texas to sit outside or not have the AC on. (And please, the question is about gas consumption, not wasting gas. I often work out of my car and am NOT running an Air Conditioner in a 250 Sq. Ft. office)
When idling and just driving the AC, the engine is working in a very inefficient mode. The AC is only drawing maybe 3 to 4 horsepower. The engine friction and compression and valve train are probably using 10 to 20 horsepower. So you’re only benefitting from say 3/ 15, or 20% of the horsepower. In other words you’re using up almost five times as much gas as necessary.
Ideally cars would come with a 5HP putt-putt gas engine to drive the AC, now that would be much more efficient.
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