Quote:
Originally Posted by planetaire
Hi
I use since 10 years a toyota prius in electric mode only. I close the front totally except in summer when temperature is say 30°C or more. When the front grill est blocked, the drag needed due to colling is zero Newton and zero percent of the total drag.
At the opposite, previously, 11 - 12 years ago I drove the same car in hybrid mode, I can very rarely close the front grill, the engine could quickly goes over 95°C.
So I am sure that in electric mode this car need much less cooling then in gazoline mode.
A second point is that pourcentage is not the value I would prefer, Newton is more suitable because for a car having a gazoline version and an electric version, the Cd of the electric model is lower (E-niro... for exemple). So using a pourcentage of a number lower is not a very good way if the purpose is to compare two type of energy.
A third point is that actual ev car have a grill shutter (Ioniq, ID3, ID4...). If you want to know the cooling drag, Newton or %, you need to know when this grill is open or not.
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1. Closing off the cooling in low-power electric mode in a Prius tells us nothing relevant to this discussion (which is about BEVs), does it?
2. Cd values (or percentages of total Cd) are used for cooling systems because it is a coefficient. If we used Newtons, we'd need to specify speed. We can easily work out the force for any car for which we have speed, area and cooling drag Cd.
3. Shutters apply equally to all cars these days - ICE, Hybrid, BEV. Cooling drag is with the shutters open ie the cooling system working.