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New technology makes software-only AFM possible


Zane

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Skipfire.jpeg
By Zane Merva
Executive Editor, GM-Trucks.com
1/5/2015
GM Ventures is taking the wraps off brand new technology designed to take the company's existing Active Fuel Management system into a new software-only era.
A 2012 GM Ventures Equity Investment, Tula Technology, Inc has developed a unique digital control system that can "skip" cylinders firing to save fuel. It's called Dynamic Skip Fire (DSF) and it may change everything you know about how an internal combustion engine fires.
The press release says it best:
"Instead of relying on fixed cylinder deactivation or switching between fixed patterns like current multi-cylinder engines, Tula’s DSF technology continuously makes dynamic firing decisions on an individual cylinder basis to deliver the required engine torque for all vehicle speeds and loads while avoiding vibration.
Independent testing commissioned by Tula shows that the application of DSF technology can improve fuel efficiency in a multi-cylinder engine (4/6/8 cylinders) by as much as 15 percent when compared to a vehicle equipped with an engine that does not have cylinder deactivation."

 

In short, GM has replicated the mechanical attributes of displacement on demand with a digital software solution. Will this technology see the light of day in the future? We sure hope so.

Skipfire.jpeg

Skipfire.jpeg

Skipfire.jpeg

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Gotta love tech.

Without tech advances, we'd still be looking for lightning strikes to get fire.

 

and we know when it will happen ............5 nov 1955 on the clock .........doc Emmeth Brown know this lolll

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This really isn't that much different than the current setup except it can shut down any of the cylinders instead of the same 4. It looks like it still uses the same concept of the lifters. Google dynamic skip fire and read the PDF document/paper on it.

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Forget about retrofit, it says the block has to change to improve oil distribution. Too bad, I own a 6.0L pig.

 

I seem to remember that one of the AFM limitations was having to turn it off after a little while to prevent some cylinders from overheatin. By randomly shutting any of the 8 cylinders in stead of only controlling four, it would eliminate this issue.

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I used to have an old car that had a messed up distributor, it was a V8 and would idle like crap because it was missing 2 cyl all the time, but at speed I would never know that it had a misfire. The only time I notice my V8 in my 07 Tahoe going into 4 Cyl mode is the noted change in the DIC, and there is a growel, it is not noticable unless I pay attention to it. This is a good idea, but I think if they combined it with V.V.T. They might be able to make it seamless...

 

Of course to the person that bought a V8 to own a V8, when driving I would be surprised if you noticed any lack of power. I know when I put my truck into trailer mode it will not use the 4 Cyl option, at least it has not done it.,

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Normal driving I never notice the change from 8 to 4 mode. The only way I can sense it is if I see it in the display on the dash. I can try to feel that it's changed, but really I can't unless I also see it on the display and then I can sense something has changed in the engine. A small press on the gas and there is no sense of loss of power at all. None. Those who complain about it either 1. have an engine with an issue that needs to be fixed or 2. just need something to bitch about. I work with a lot of contractors, and they have never needed 8 cylinders 100% of the time. I think this new method described here would be even more seamless and probably more likely to work better, as the skipping would be more fluid than a full 4 cylinder shut off. Seems to me it would be better for engine life too.

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  • 3 weeks later...

I guess I am a throw back to the past. I view most things mechanical I buy as I did things in general growing up on the farm and when I did my time in the military. Everyone does their part. I bought 8 cylinders. None of them gets to take government, union, or EPA inspired breaks while the others work. No sir. Everyone pack the gear and pulls the load. I shut off the AFM cylinder shut down gig on my 2013 the day after I bought it brand new and brought it home.

 

Could be that I am very noticeable of any fluctuations in an engine, because I deal with a lot of commercial equipment engines and ag equipment engines, that I noticed the AFM shut down thing just driving the pickup home from the dealer in 15 miles. Lots of rolling hills in my area and I could tell when it went from 4 cyl back to 8 when going from a flat to starting a climb a hill. Even the wife noticed it. I just looked at her and said, this has got to go bye-bye. Almost caused me to take the pickup back and dump it back in the dealer's lap. But instead, I just disabled it.

 

Might be why my pickup runs great, gets about the same average mpg as anyone else, and uses less than 1/4 quart of oil in 7000 miles. I dearly love technology, but not all technology is beneficial.

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Might be why my pickup runs great, gets about the same average mpg as anyone else, and uses less than 1/4 quart of oil in 7000 miles. I dearly love technology, but not all technology is beneficial.

So your truck gets the same average mpg as a truck with AFM? I wonder why GM engineers spent millions of dollars and years introducing and implementing AFM for no added benefit.

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