Quote:
Originally Posted by mort
Ugh, I hate doing this. Usually I can abide by the old saw that if you can't say anything nice don't say anything. But this thread has gone way stupid lately and I feel compelled to comment. So I'll get the nasty part out of the way first.
There are pumping losses, that is there is power needed to pull the charge into the cylinder and that power, which could have been used to propel the car, is instead wasted in suction across the throttle. And second, a loss of efficiency due to the charge in the cylinder being sparse, the sparse charge results in lower pre-ignition temperature and just like running an engine with a lower compression ratio, the thermodynamic efficiency suffers. My claim is that the thermodynamic efficiency drop swamps pumping power. I will call this view the "reality position."
...a bunch of stuff that eventually gets to the big picture
-mort
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Diesel technology: report of the Technology Panel of the Diesel Impacts ... - National Research Council (U.S.). Diesel Impacts Study Committee. Technology Panel - Google Books
So your position agrees with the article above that a motor that does not have a throttle can provide up to double the fuel economy under low power conditions as compared to a vehicle with a throttle being operated under low power conditions?
In other words you left each loss that results from the throttle existing separate although in reality the combined effect is rather large and the subsequent effects are a result of the throttle being used.
Precision can be deceptive.