Dynamic Cylinder Deactivation

[t vago]

Originally Posted by visionary

You have made some sweeping assumptions about the operation of many ECUs and the programming logic behind them, which is unlikely to be borne out upon close inspection.
I have never had an install throw a fault code with this tech - sorry!

And you are making sweeping generalizations from seeing the results of installed aftermarket traction control systems (sorry, missed that part).

Unless I'm mistaken, traction control only engages when wheel slip is detected. That sort of situation would either happen for a period of perhaps seconds (if traction loss is detected while driving) or upon acceleration (traction loss due to acceleration). Either situation is not comparable to regular cruising.

This is an entirely different situation from regular cruising. I will grant that engine misfire monitors for early OBDII cars did not detect the full range of engine operation conditions, but they would certainly operate during regular cruise mode. Engines can and do misfire all the time, but engine computers are programmed to ignore momentary misfires. They will certainly pick up misfires that occur at least once per two crankshaft revolutions over a period of greater than a few seconds.

Don't believe me? Rig up a toggle switch to shut off one fuel injector, then engage that switch while doing steady driving down the road. I guarantee you'll get either a P0300 or one of P0301 through P0308 (misfire detected in cylinder 1 through 8). To the engine computer, it doesn't really matter if the misfire only occurs in one cylinder or equally among all of them. It will still see the loss of power due to the shut off cylinder.

[visionary]

t vago - I was on your side!
But since you posted, I will explain.
I posted racelogic in order to give you an opportunity to review the technology but since you did not, I will summarise thus - although traction limiting conditions only occur for relatively short periods, the same unit has engine speed limiting capabilities including "launch control" which can operate for very long periods at high cut percentages, without fault code recognition
My first-hand experience is at variance with your theoretical knowledge, without declaring a loser shall we leave it that "the proof is in the pudding"?

Why is it so hard for you to believe that this could work? Cut the guy some slack. We should be champions of new and original thinking, not strangling things at birth! Lets see if he can do some proper testing and declare some fair results, then subject them to objective criticsm.

[t vago]

Originally Posted by visionary

t vago - I was on your side!
But since you posted, I will explain.
I posted racelogic in order to give you an opportunity to review the technology but since you did not, I will summarise thus - although traction limiting conditions only occur for relatively short periods, the same unit has engine speed limiting capabilities including "launch control" which can operate for very long periods at high cut percentages, without fault code recognition
My first-hand experience is at variance with your theoretical knowledge, without declaring a loser shall we leave it that "the proof is in the pudding"?

You claimed to be "on my side," yet are so enamored with the idea of deliberately throwing the engine into limp-in mode to save fuel that you're willing to sound like heihetech.

Steady cruising is not the same as momentary slippage, it is certainly not the same as launch control, and you really should know that. If you're willing to try to convince people here that stomping on the gas and putting the engine computer into WOT mode (which is open loop, BTW) is the same thing as cruising down the road at part throttle, you've got a lot of work ahead of you. Proof in the pudding, indeed. Why not rig up one of your aftermarket traction control devices to work in this manner? All you'd have to do is install it onto a test vehicle, and then cut the wheel speed signal to one of your driving wheels with a switch. Right?

Originally Posted by visionary

Why is it so hard for you to believe that this could work? Cut the guy some slack. We should be champions of new and original thinking, not strangling things at birth! Lets see if he can do some proper testing and declare some fair results, then subject them to objective criticsm.

He's been pushing this technology since 2008. He's claimed to have had a working box since 2008. He supposedly won an award from some automotive chip supplier, which implies he had some sort of working prototype. Why not do some digging of your own?

You could argue the same way for HHO.

[Frank Lee]

Originally Posted by t vago

Well, the onboard engine misfire monitor would notice incorrect crankshaft angular accelerations/decelerations from intentionally shutting off cylinders in the pattern that heihetech suggests. That would throw a P0300 DTC (multiple engine misfires detected), cause the CEL to turn on, and would cause the engine to go into open-loop mode. The engine would go into open-loop mode because the engine computer programming would assume that O2 sensor output is flat-out no longer reliable due to the existence of repeating randomly misfiring cylinders, so it doesn't even matter whether or not heihetech's magic black box has a WBO2 sensor with narrowband output to the engine computer.

Since the engine computer would not know any better, it would then assume that the shut-off cylinders were exhausting unburnt fuel into the catalytic converter(s). Assuming this, the engine computer would cause the CEL to start blinking, and would go into limp-in mode to lower engine power in an attempt to mitigate assumed possible catalytic converter damage. This would cause ignition timing to be retarded, which would cause engine efficiency to be lowered.

I would sure hope that this system consists of more than a toggle switch. Therefore it should compensate or deal with these factors.

It's possible, but not very likely, that physical engine damage (broken crank or conrods) may occur, due to the unbalanced nature of an intentionally misfiring engine.

Now you're just being a drama queen.

[Frank Lee]

Yes Frank - it will.

I don't think the rationale supports it.

[t vago]

Originally Posted by Frank Lee

I would sure hope that this system consists of more than a toggle switch. Therefore it should compensate or deal with these factors.

I really doubt it. It's kind of hard to mask angular deceleration of the crankshaft due to misfire. Earlier, OBD-I controlled vehicles would have no problems with this. However, you're talking about cars that would be at least 15 years old.

Originally Posted by Frank Lee

Now you're just being a drama queen.

Just anticipating the inevitable "will it break the engine?" questions.

[Dunkler]

Here's the bottom line. I would be willing to try it given my guidelines and post in excruciating detail the truth, one way or the other. Then we could totally close this thread.

[dutchboy]

Originally Posted by t vago

I really doubt it. It's kind of hard to mask angular deceleration of the crankshaft due to misfire. Earlier, OBD-I controlled vehicles would have no problems with this. However, you're talking about cars that would be at least 15 years old.

So anyone wanting to experiment or actually implement cylinder deactivation should go with an OBD-I based car then?

I don't see 15 year old or older cars being a problem. Most of the cars I like are older/discontinued and automakers seem to have forgotten how to make cars get great gas mileage. That or they intentionally sabotaged their conventional ICE models to make their expensive hybrids seem like a better deal than they are.

[euromodder]

VW will be introducing dynamic cylinder deactivation on their new direct injection 1.4L TSi.
According to VW, their 2 cylinder mode is active in 70% of the NEDC cycle, so expect some seriously improved fuel economy - at least the oficial numbers will look better.

[NeilBlanchard]

Right -- here's an article with some technical details:

Green Car Congress: Volkswagen to implement cylinder deactivation in 4-cylinder 1.4 TSI engines in 2012