Does anyone know where I can find the algorithm for the Variable Cylinder Management (VCM II) system? i would like to know the details on when (what conditions) the engines mgmt decides to run on all cylinders or shut off 1 cylinder or shutdown 3 cylinders. i expect that this is not a secret, as I would simply like to know how a product's critical system, functions.
TIA

 

This is the best explanation I found so far:

http://world.honda.com/automobile-technology/VCM/

 

Thanks. That link is good info on what VCM is and how it saves fuel.

Not sure why it's so hard to find the information that i am looking for.

 

How about at idle?

 

That would be the same as "braking to decelerate", no fuel is given to the engine.

 

basically you only get all 6 cylinders if you're at WOT?

 

No, anything more than cruising will kick in 4, 5 or 6 cylinders. ID imagine there are only a few light throttle situations where only 3 cylinders are firing.

 

Guys,
VCM operates in 3 or 4 cyl modes, there is no 5 cyl mode.

Either sealing off all 3 cyl in one bank (leaving the other bank of 3 active) or 1 cyl in each bank (leaving 4 active).

During hwy cruise I noticed VCM can steadily remain on at around 70mph even with slight uphills. It's still on at 75mph but any slight inclination and it turns off.

I really don't know where 4 cyl mode comes in.
For idle; 3 cyl mode may cause rough idling so who knows.

I really hate how on the RDX there is no VCM indicator in any of the screens.

 

Doesn't the instant mpg bar graph sort of act as one? When it goes above 40 mpg it's either in 3 cylinder mode. If you are off throttle and coasting you are in no cylinder mode. When it drops to 20 mpg or less it's in 6 cylinder mode.

 

Haha .. that is true.
But it's hard to tell, did the mpg just drop because of the downshift (higher RPM), deeper accelerator or just because VCM turned off?

I'm not hoping for a Honda like blue green light sceme or a special dash light, just a simple indicator on the MFD (while in MPG mode) would suffice.

 

So, in the end, i guess there is no definitive document or web page by Acura, that shows the exact condition when cylinder deactivation happens on the RDX.
Perhaps the answer is too technical and could only be understood by mechanical engineers, or perhaps the average RDX owner does not really care how the VCM in their car works.