Dynamic Cylinder Deactivation

[Dunkler]

I understand what you're saying. What about a certified mechanic who works for a company?

EDIT:

And why haven't I received my free DCD controller yet!

[Frank Lee]

That's between you two.

[t vago]

I would agree about this being the owner's responsibility if the item in question were a product already released for general consumption. However, if I were offering something to be subjected to testing on somebody else's vehicle, I'd want to make sure that the guinea pig's vehicle would either not be damaged as a result of the item being tested, or that the guinea pig would be compensated for said damage if it occurred as a result of the testing. Negative blowback could be substantial, I would think.

Yep, heihetech should have offered to install his wonder gadget himself in Dunkler's car.

[Frank Lee]

What do you guys think might happen? The thing is basically an artificial limp home mode...

[visionary]

I’ve had so much fun reading through this thread that I could’t resist making a couple of points myself

I take my hat off to Frank Lee who has good knowledge and a realistic attitude to mods. As anyone in the performance car market will tell you, “the warranty is only good until you open the bag”.

I sympathise with t vago who has “got off on the wrong foot” with the manner in which heihetech has presented his invention and who would not be sceptical about this sort of thing, especially when “butting heads” with an obviously commercially driven newbie, who has blatantly misused the forum for his own ends.

BUT – this thing will work.
Its not a new concept – most aftermarket traction control systems use this injector signal intervention method to limit hp and therefore tyre slip. It works seamlessly and without negative side effects. Installation is simple (insert unit in wiring loom between ECU and injector) and it can be switched on/off by driver at any time.
Cut tables (decision about number and order of injector interventions) are installer programmable by laptop – I’ve fitted loads and it’s a very smooth process.

If heihetech has done his design work correctly he will have included a user-definable scale of cut operation from 1cylinder-10%(of available pulses) up to 6 cylinders-30%. This should be linked to a TPS signal so during high power demand the system is disarmed. The unit should have been designed a single 12 cylinder unit and the installer activates the correct number of cylinders for the cars, that way you only make one box and reduce your production costs.

So well done heihetech but forget about that patent you’ll never get it. Any patent search will produce so much “prior art” that you will have nothing you can enforce, and its you money that you have to spend defending the patent against infringement – with little chance of success you may as well burn the money!

Hope this helps calm the waters

[Frank Lee]

BUT – this thing will work.

It will work to disable cylinders and cut power, but will it do the intended function of improving fe? I think not.

[t vago]

Originally Posted by Frank Lee

What do you guys think might happen? The thing is basically an artificial limp home mode...

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.

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.

[t vago]

Originally Posted by visionary

Its not a new concept – most aftermarket traction control systems use this injector signal intervention method to limit hp and therefore tyre slip.

There's a slight difference. This what you mention was integrated from the factory to work. heihetech's magic box is a hacked-in afterthought that does not actually communicate with the vehicle's engine computer.

Originally Posted by visionary

It works seamlessly and without negative side effects. Installation is simple (insert unit in wiring loom between ECU and injector) and it can be switched on/off by driver at any time.
Cut tables (decision about number and order of injector interventions) are installer programmable by laptop – I’ve fitted loads and it’s a very smooth process.

Really? And how did you prevent the engine computer's misfire monitor from noticing the misfires?

[visionary]

Yes Frank - it will. During those times when the engine consumes fuel to make power we don't use (light throttle and cruise conditions) switching off injectors will save fuel. Not as efficiently as some other methods granted - but when you think of the effort we go to with hypermiling techniques this is a simple idea to get similar results. The real question is how clever has heihetech been with his design to get the best from this technology?
If his customer liason skills are anything to go by, I think it'll have a few bugs in it!

[visionary]

t vago - this is where I think you are a bit confused about how it works.
The systems I have installed (look up Racelogic Traction Control) are aftermarket not factory. They only cut injector pulse, and not the same injector and not all the time. The misfire is so soft that it is not easily detectable. Most 90's and early 00's ECUs have no source of feedback to detect this type of misfire. More modern stuff may have but not all cars will - so there is a need to test which.
Please note I have great respect for your opinions and knowledge, and I agree with all the thermodynamics points that you made, but. 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!