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Old 10-05-2010, 10:12 PM   #21
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[YT]http://www.youtube.com/watch?v=ccEjiicrN6g&feature=related[/YT]
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Old 10-05-2010, 10:40 PM   #22
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I have no problem with most Forum links, but linking to a Forum that competes with any of ForuMediaInc'* (Our owner) gets pulled. And one Bonneville one in particular gets a ban.

I shouldn't have said 99%, but this Forum was built and most frequented by people looking to increase HP and care less about MPG efficiency. Not that it isn't interesting, just not most our cups of tea. Never seen a tree hugger with a supercharger before. I guess I stand corrected.
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Old 10-05-2010, 11:41 PM   #23
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The Millenia engine is a bit dated but IMO if the concept was updated it could do quite well.

With an engine that has variable cam timing and lift (pretty common now a days) it'* only a matter of programming the Miller cycle maps into the pcm.

Think about it.. from MPG queen to however much power you could typically make with a standard engine.. just with the touch of a button.

Positive displacement blowers have much better compressor maps now and are much more efficient. So, an updated blower would boost efficiency too.
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Old 10-06-2010, 12:09 AM   #24
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Can a variable cammed engine be altered enough to create a Miller cycle. Or enough to provide better efficiency yet power as needed by the TPS sensor lets say.

It'* the lounge and I was being facetious about two automakers I don't particularly like. But explained a little better, the technology certainly spikes my interest.
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Old 10-06-2010, 12:15 AM   #25
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Quote:
Originally Posted by GXP Venom View Post
Can a variable cammed engine be altered enough to create a Miller cycle.
assuming intake and exhaust are individually controlled, i don't see why not. could retard exhaust as well in an OHV application, but it kills VE in lower RPMs, making less power, but also makes more scream at high RPM...... FWIW.
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Old 10-06-2010, 12:30 AM   #26
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Just wondering if that would go beyond the degrees todays VVT'* can achieve. But it sure sounds alot better than the 4-6-8 cylinder Northstar attempt at giving an engine both sides of the fence.
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Old 10-06-2010, 12:35 AM   #27
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well, the LZ9 3900 supposedly can advance AND retard by 25* and that'* OHV.... IIRC, the 3.6 can go even further.
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Old 10-06-2010, 12:38 AM   #28
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It very well could.

All the Miller or Atkinson cycle does is keep the intake valve open longer. So as the piston travels up, the intake valve is still open for about 20-30% of that stroke. Aside from the intake cam lobe, it'* a normal engine.

Two things happen here.
1. Reduced pumping loss since the engine isn't pumping against a closed valve. It takes energy to compress air in the cylinder.

2. The expansion ratio is increased during the burn cycle.

To explain 2 a little better..
4-stroke engine.. So you got Suck, Squeeze, Bang, Blow. 1, 2, 3, 4.

The bang is where you get all your work from. But the amount of work is limited to how far the burning gases are allowed to expand. The piston only goes so far then it blows everything else out. What if you could get more work out of the bang by letting the gases expand more/longer instead of blowing that wasted energy out the exhaust? That'* what the Atkinson/Miller cycles does.

The first Atkinson cycle engine had a variable crank so that the bang stroke was longer than the suck stroke. But there'* an easier way to do it with a normal crank.. By keeping that intake valve open during the squeeze stroke, you're reducing the effective displacement by that swept amount. So, the air being compressed gets to expand 20-30% than the amount it was originally compressed. More expansion on the exhaust side means more work and less wasted energy.

So, any engine that can alter the timing of the intake valve independently, can be turned into an Atkinson/Miller cycle engine. It'* just a matter of programming when you want the extra intake valve timing.. And variable cam timing like this is very common.
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Old 10-06-2010, 08:01 AM   #29
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I don't care what car it is, but you can't beat the sound of a supercharged engine.
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