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Mount Vernon, WA | I just went to the Cummins QuickServe website and found a spec for maximum permissible oil temp for an ISX (truck) engine. It is 252 degrees. Pretty much the same as the 257 you quoted for the Deutz.
Just because the EXTERNAL cylinder fins on a Deutz run at 300 degrees plus, this does not mean that the INTERNAL cylinder wall temps differ that much between a water-cooled and an air cooled engine. Just look at how much more cooling surface area there is on a Deutz.
The oil temps in a water cooled engine are typically 20-30 degrees higher than water jacket temps, so if the cooling system is running at 210, then the oil is going to be in the 230-240 degree range, and so the overall INTERNAL engine temps (exhaust, oil, piston crown, valve, etc.) are pretty much the same between an air cooled and water cooled engine.
An aluminum piston is basically the same, whether it's used in a Cummins (or Deere or Cat or whatever) or a Deutz engine. The cylinder wall temps cannot exceed "x" (whatever we want "x" to be) without causing overheating and subsequent scoring of the piston and cylinder wall. We KNOW that running a water-cooled engine much above 230 or so will cause problems with piston scoring. In my professional opinion, this gives the air cooled engine NO advantage in the fuel efficiency department.
What I'm trying to say is that the INTERNAL temps of a Deutz engine cannot be significantly (if any) higher than that of a water-cooled engine, hence no real fuel economy advantage.
NOx levels are more a function of exhaust temps than cooling system temps. If indeed, as you say, a Deutz engine is more fuel efficient for the reasons you stated above, then NOx levels should be LOWER in a Deutz, because that means that more of the heat energy of the fuel is being converted to useable HP, which should translate to LOWER exhaust temps and lower amount of NOx. | |
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Deutz Air Cooled Irrigation Engines ?
