With all this dicussion of "minimizing pumping losses"

[imzjustplayin]

Originally Posted by R.I.D.E.

Think of it as a "cylinder filling event"

In order to fill the cylinder for every combustion pulse you must allow all the air in that the cylinder needs to fill completely.

Using a vacuum guage at 1200 RPM in high gear slowly depress the gas pedal until the vacuum drops to a point then levels off. That is basically where your "cylinder filling event" has occured. Adding throttle really makes little difference after the vacuum has dropped to its lowest point. Going beyond this can use more fuel in some systems.

Pumping losses are the essental components of cylinder filling events. Decrease the throttle and you starve the engine for air. It responds by loosing power.

gary

So how do you know if the engine will use more fuel past that point? Does the OBD provide this sort of vacuum information and whatnot?

It's interesting to see everybody advocate P&G yet isn't it conventional wisdom that cruise control saves gas? I mean don't most people let the throttle get away(there is a word for this) and when they realize they've increase speed, they let off the throttle, only to do this again? I remember reading some article somewhere saying how cruise control can save you fuel. Also it is said that because it requires more energy to increase speed than maintaining momentum that P&G technically shouldn't be saving but wasting more gas.

Are these people that say these things going mostly off of theory and not in practice like we all do?

Also has anybody considered using a stirling engine to power a compressor for an airconditioner? That air conditioner would cool the engine coolant and then the engine could allow for hotter temperatures and so on? Can you reduce NOX by reducing the temps of the coolant?