Quote:
Originally Posted by aerohead
Aside from the discrepancy between the heat content of Diesel fuel compared to gasoline,the reason a Diesel engine is more efficient than a gasoline engine is it's lack of a throttle plate,running always at W.O.T..
If you add an additional restriction to your gasoline engine's induction system you're shooting yourself in both feet.
If anything,you want a Mitsubishi GDI research engine of the 1990s,which is throttle-less,and picks up 15% thermal efficiency accruing only to its LACK of intake restriction and superior volumetric efficiency.
Save turbulence creation for your combustion chamber design.That's where it counts.
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I'm with you, at least somewhat. Yes the restriction is counterproductive. Think of it this way, if you stretch out the air to twice it's original volume and then squeez it into a 10:1 compression ratio, do you still have a 10:1 compression ratio or a 5:1?
There is one drawback with WOT on a gasoline engine. When at WOT the cylinder temps get so high that detonation becomes a problem. The common "fixes" have been to not only retard ignition timing, but to enrich the AFR way past stoichiometric. (Which is the reason even new cars smell just as bad as old cars when the fly by you at full throttle going up a mountain pass). I'm wanting to try to use cooled EGR as an alternative so I can hopefully keep my AFR lean at WOT.
In order to keep the throttle open wide I'm sticking with a smaller engine. Plus, I'd like to install taller gearing in the transmission.
As far as having two restrictions as being a shot in the foot I don't thinks so. The average restriction will tend to be the same. Since the Jet-A-Vator imposes a slight restriction I'll have to keep the throttle plate slightly more open to maintain the same speed. The only way I could maintain a constant WOT might be to hook an engine up to a generator that matches full output of the engine.