Why No Aircooled Cars?

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Why Not Aircooled Engines?


Aircooled cars have some inherent advantages over watercooled engines.

The have no radiators, water pumps or coolant hoses. This means there are no opportunities for leaks and possible overheating issues.
The engines are lighter and cheaper to manufacture.
Beacause there are no ancillary plumbing strutures they are easier to work on.

Possible disadvantages are less efficient heating for harsh winter climates although aircooled engines warm up faster.
They are noiser because of the lack of the sound damping effect of a water jacket.

I have experience with several VWs, older Porsches and even owned a Corvair. They never gave me any engine troubles and even kept me adequately warm during many awful Chicago winters.

With modern metallurgical and manufacturing advances the reliability of aircooled engines could be as good as watercooled ones. There is no reason why cars can't be made FWD or even AWD aircooled. While the boxer engine has the most common configuation it is possible any number of V type engines could be designed.

In the current automobile culture where gratuitious complexity seems to be the only profitable direction could it be time to return to the old fashioned idea of K.I.S.S?
 
I wouldn't be surprised if this is something that we see more in the future in hybrids for weight saving and packaging.

However, I think the biggest disadvantage is temperature control. A watercooled engine stays at a stable temperature regardless of load conditions. I'm sure for fuel economy and emissions, stable temperature control is ideal.
 
With modern oil cooling systems on some air cooled engines that use fans and radiators almost as large as water cooled engines wear and tear is not longer the issue it once was. IMO its the inherent mechanical loudness (while not as loud as they used to be) of the engines themselves, with no water jacket to dampen the noise they too many people may find them obnoxious.
 
Performance and reliability would not meet today's standards for a daily driver, I don't think.
 
Because a liquid-cooled engine can be properly designed to be MUCH more efficient, as the coolant can be routed to "hot spots", etc.

Air-cooled motors are an exercise in over-building with no return except simplicity, and water pumps etc. last many many many miles in a quality vehicle today, so the added efficiency and power is worth "putting up" with them.
 
Air cooled engine in a car or truck with a large displacement engine? No thanks.

They're fine for smaller engines, even some of the older cars with limited displacement. But most people don't want a lawnmower engine in their pickup.
 
As a 3-5 yr old my father took me from California to Dallas,tx in a VW bug. We went in the summer, across the deserts with no problems at all.He used PZ 10w40 in the bugs he had,
 
A modern emissions control system requires a consistent engine temperature to properly dial in all the parameters. A varying temperature in an air cooled engine is bad news for that.
 
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Originally Posted by Fawteen
Air cooled engine in a car or truck with a large displacement engine? No thanks.

They're fine for smaller engines, even some of the older cars with limited displacement. But most people don't want a lawnmower engine in their pickup.


Oddly enough, Jay Leno's tank engine car uses a large air-cooled V-12, so large displacement air-cooled engines for land vehicles do exist. Seems to me Franklins from the 1920s had air-cooled V-8s and V-12s.
 
Originally Posted by Snagglefoot
A modern emissions control system requires a consistent engine temperature to properly dial in all the parameters. A varying temperature in an air cooled engine is bad news for that.


^^^^^ This
 
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THE EPA! That's why. Also the air cooled motorcycles they make typically overheat too, so I don't see how it would work better in a car.
 
Originally Posted by Dave Sherman
Oddly enough, Jay Leno's tank engine car uses a large air-cooled V-12, so large displacement air-cooled engines for land vehicles do exist. Seems to me Franklins from the 1920s had air-cooled V-8s and V-12s.

WWII M-4 Sherman tanks used a variety of engines . Some used air cooled rotary engines , similar to those used in some airplanes . Think some of the tank destroyers did too .
 
Originally Posted by Passport1

Why Not Aircooled Engines?

Snip


I have experience with several VWs, older Porsches and even owned a Corvair. They never gave me any engine troubles and even kept me adequately warm during many awful Chicago winters.

Snip


VW aircooled kept you warm in Chicago winter. What color is the sky in your world? Had to have ice scraper for inside at the ready in mild kansas winters, yes, had the heater boxes on the head pipes too.

How about cylinder 3 failures from overheating from oil cooler.

Rod
 
+1
Neither of the air cooled VWs I owned kept me warm in the Wisconsin winters. I too had to use an ice scraper on the inside of the windows while I was driving.
 
Originally Posted by Ws6
Because a liquid-cooled engine can be properly designed to be MUCH more efficient, as the coolant can be routed to "hot spots", etc.


Maybe, maybe not. Air cooled engines may run with cylinder head temperatures as high as 500 deg F. This means less combustion energy is wasted into the cooling system. Aircraft engines are air cooled and have been able to match the thermal efficiency of a Prius engine for the last 70 years.

Put another way, there are valid reasons why air cooled engines continue to be the choice for aircraft. Efficiency, power to weight and cooling drag are all positive factors. Reliability and poor internal dimensional control may not be among the good points though...

EDIT: I'm not making the claim that modern liquid cooled engines are worse, or are somehow inadequate for aircraft. Only that air cooling has some interesting technical points.
 
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I don't think temperature can be controlled as well in an air cooled engine. With current emissions regulations my guess it would cost a fortune to create an air cooled engine that could meet current emission regulations. I don't think it's financially feasible for the auto industry to even try.
 
there's a video on this on youtube. In addition to emissions limitations, as they wanted to get more hp out of smaller engines, you have to deal with the engine throwing off more heat and it was hard to do this with air cooling. They couldn't make an air cooled engine as powerful as water cooled.
 
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