ShirBlackspots

While I believe its @F150Torqued trying to figure out the purpose of the Charge Motion Control Valve, its mentioned on the Wikipedia what it does . It doesn't make any mention of it for the 5.4L 3 valve, but the screenshot here is of the 4.6L 3 valve. Here's a further description of the CMCV: called Variable Length Intake Manifold. I was randomly perusing the Wiki, had started out with Transmissions, and wound up on the Ford modular engines.


Description of the CMCV on the Wiki.

Also of note:

F150Torqued

Thanks for the supporting reference material.
I think I got that part. My issue with it is a 'tad' deeper concept than that. I understand its purpose. When it is completing what it does - what are the units it is using and what would you call the task it is accomplishing?

Freak007

Not entirely sure I understand the question... But I can definitely explain why manufacturers want to vary intake manifold runner sizes...

Bare bones, absolute basic - all else being equal, the longer the runner, the more low end torque an engine will produce, and the better the low range throttle response. The shorter the runner, the better high(er) RPM power is made. Why? Because the longer runner better isolates each intake valve from it's peers. This helps prevent the intake pulses of each cylinder from "fighting" with the others to fill at low(er) RPMs. The higher air velocity in the longer runner also helps stuff more air into the cylinders. At some point though, the restriction of the longer runner becomes a hindrance to filling the cylinders, velocity is no longer an issue either as RPMs of the engine alone has created the velocity required. At this point a shorter runner, or even a direct connection to the plenum becomes beneficial.

In short, intake manifold runner tuning helps to reduce emissions by providing a more complete burn at all RPMs. This "better burn" also helps make the torque curve flatter and more user friendly.

I am unaware of any system that utilizes more than 2 runner positions.

River1

I think the valve is about Volumetric Efficiency (VE). Of course that can mean almost anything depending on the purpose of the engine. In this case wouldn't it be about a balance of power, fuel economy and emissions?

For this consider naturally aspirated engines only to reduce the variables involved although the principles are the same for boosted engines. An engine is often referred to as an air pump and that helps to explain a lot about how an engine works but it's really not a pump. John Baechtel explains this in his book, "Engine Airflow," better than I can. Basically though a pump is a machine that overcomes a pressure differential and an engine is a machine that creates a pressure differential. An engine doesn't overcome anything. It takes advantage of what it creates. The problem with an engine is it's asked and expected to operate over a wide range of RPM's. Each engine design has its inherent RPM sweet spots where it runs at peak efficiency and at every other RPM it runs at varying degrees of less efficiency. The purpose of the CMCV is to electromechanically increase available sweet spots and efficiency.

If you think about a water pump it is always fighting or working to move water from one place to another. That is the mechanical displacement. An engine on the other hand with its internal displacement, when running at it's sweet spots as long as it has fuel and a spark it will run on its own. Proven by the old Model T, manual throttle with gravity fuel feed. At its worse this is called dieseling. To keep it simple let's not start picking this apart by inserting variables like the effects of engine load on efficiency. Most automotive engines are inefficient at low RPM's. The CMCV is Ford's way of increasing Lower RPM efficiency by mechanically altering intake runner length. In reality it doesn't change the length, it alters where and how events take place in the runner.

Does this explain it? @Freak007 and @ShirBlackspots have explained how it works I can only hope I've helped more with the task CMCV is accomplishing. The units would depend on a specific question, VE, A/F ratio. BSFC, BSAC, etc.