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Old 01-08-2011, 11:57 AM   #52 (permalink)
IamIan
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Quote:
Originally Posted by abently View Post
Speed maintained, does not mean RPMs are maintained.
With a fixed transmission ratio ... yes it does... the wheel RPMs are directly connected to the engine RPMs and restricted via the fixed transmission ratio.

Quote:
Originally Posted by abently View Post
I'll explain it with a ridiculous example. Say during lean-burn (less fuel is injected), power at cruise RPM (say 10Kw) is halved, to maintain speed, you must correct RPM such that power is bumped back up to 10Kw. Now that RPM increase may not be so pronounced due to the improvement in efficiency with more throttle, but it will be there.
RPM changes ... are not required for changes in engine power output.

There are a wide variety of ways to change engine power output that do not directly require a change in engine RPMs to get that change in power output.

Quote:
Originally Posted by abently View Post
RPM may even decrease under IamIan example, but I doubt that would be the case unless designed to do so.
I do not know any ICEs designed to operate in Lean Burn that are not also designed to lower the operating RPMs when operating in lean burn ... as touched on previously there are several good engineering reasons to do this.

If you know of any ICEs that do not please post ... I'd like to read / research such an engine design myself, would be interesting.
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