Ford's Solution To Intake Valve Deposits w/ DI

[The Critic]

Quote:
Don't fret about deposits on the back of the intake valves that have plagued some other manufacturers' direct-injected gasoline engines, said Stephen Russ, the Duratec GDI's technical leader for combustion.

Although he called intake-valve deposits "a fact of life" for GDI engines because they lack the raw gasoline sucked in over the intake valves of a conventional port-injected engine to "wash" the valves, Ford's figured out the proper injection-timing calibration to help eliminate the problem.

But he also said the technology of injection components — particularly the high-pressure solenoid injectors — has quickly matured, meaning excess valve deposits should be a thing of the past.


http://www.insideline.com/ford/focus/2012/20-liters-is-now-a-large-engine-at-ford.html

If someone can explain how optimized injection timing is supposed to reduce valve deposits, please explain.

 

[wapacz]

Less fuel blow by?????

 

[Shannow]

Sheer guess...

Cam timing can provide EGR without an EGR valve.

Maybe optimal injection timing can wash the intake with fuel/cleaners, and the exhaust therein can provide improved vaporisation of the fuel charge, while alos improving the volumetric efficiency of hot/cold gasses.

 

[FowVay]

Maybe they program a short injection cycle to occur while the valve is open allowing for a brief exposure of raw fuel to pass the valve face while it's protruding into the combustion chamber.

 

[demarpaint]

Quote: "Although he called intake-valve deposits "a fact of life" for GDI engines because they lack the raw gasoline sucked in over the intake valves of a conventional port-injected engine to "wash" the valves, Ford's figured out the proper injection-timing calibration to help eliminate the problem."

Two things come to mind, the first thing is they are admitting a problem with DI engines. Something most of us knew already. The second thing is the words "help to eliminate the problem." That means to me, there still could be problems.

I'll give it another year or two and let them figure it out at someone else's expense, not mine.

 

[SteveSRT8]

There's another thing we agree on!

Too many unanswered questions about the long term.

The next couple of years should bring some high mileage DI engines to the shop. Can't wait to see what's up.

 

[mikered30]

I thought toyota/lexus solved this issue, or at least minimized it better?

 

[demarpaint]

Originally Posted By: SteveSRT8
There's another thing we agree on!

Too many unanswered questions about the long term.

The next couple of years should bring some high mileage DI engines to the shop. Can't wait to see what's up.

Time will tell, improvements will be made at the consumers expense. I hope they ditch the idea, but that would be a long shot!

 

[sciphi]

GDI is likely here to stay. The makers have far too much $$$,$$$,$$$ into it to throw it all away now.

Like other posters in here, I'll wait a few years for them to iron out the issues. The port-injected engines are doing just fine, TYVM!

 

[Rob_Roy]

Originally Posted By: SteveSRT8
There's another thing we agree on!

Too many unanswered questions about the long term.

The next couple of years should bring some high mileage DI engines to the shop. Can't wait to see what's up.


I am also eager to see how these engines look after some high mileage. I have seen some scary pictures of valve deposits at low mileage! Maybe it is time to bring back the Marvel Inverse Oiler...

 

[d00df00d]

Originally Posted By: The Critic
If someone can explain how optimized injection timing is supposed to reduce valve deposits, please explain.

My understanding:

I'm oversimplifying here, but early DI engines ended up essentially spraying fuel into parts of the combustion chamber where it would not be fully burned. This was really only a big deal on the US market, where our emissions regs required slightly rich running for reasons I don't fully understand. The excess fuel would of course get into the oil and volatize it. Volatile oil components would cook off, get into the intake tract through the PCV, and land on the intake valves, where there was nothing to stop them from accumulating.

If you get the injection parameters right, you prevent the fuel dilution from happening. As long as you're not using a poor quality oil (for your application) or overextending your OCIs, there's nothing to cause deposits in the first place.

 

[d00df00d]

Originally Posted By: demarpaint
Two things come to mind, the first thing is they are admitting a problem with DI engines.

"Inherent disadvantage" would be a better term IMO.

Every design has strengths and weaknesses. GDI gives you more power, better fuel economy, and better emissions; the weaknesses are cost, complexity, and that there might be problems if everything isn't running just right.

Over time, cost will become less of an issue and the systems will become more reliable. We will see if that will be enough.


Originally Posted By: demarpaint
The second thing is the words "help to eliminate the problem." That means to me, there still could be problems.

That was a bit of CYA on their part, but I agree with you.

 

[demarpaint]

Originally Posted By: Rob_Roy
I am also eager to see how these engines look after some high mileage. I have seen some scary pictures of valve deposits at low mileage! Maybe it is time to bring back the Marvel Inverse Oiler...


I mentioned the Inverse Oiler a few times, it might actually work if it is used before the deposits really have a chance to anchor on.

 

[d00df00d]

Originally Posted By: sciphi
GDI is likely here to stay. The makers have far too much $$$,$$$,$$$ into it to throw it all away now.

They might not give up on it any time soon, and it certainly will stick around for some applications (e.g. supercars that still need to meet emissions/fuel economy regs). That doesn't mean it'll be around forever or end up in all our cars. Time will tell...

 

[kr_bitog]

The new solution for GDI is using multiple injection with very short injection cycle, to made very homogeneous mixture, but this very high pressure pump also sap a lot of power

 

[Quest]

Originally Posted By: kr_bitog
The new solution for GDI is using multiple injection with very short injection cycle, to made very homogeneous mixture, but this very high pressure pump also sap a lot of power


Ditto!

That has been my understanding to GDI engine designs so far (in order to minimise/overcome intake valve deposits)

Q.

 

[bepperb]

Originally Posted By: mikered30
I thought toyota/lexus solved this issue, or at least minimized it better?


They didn't really solve the issue, their Direct Injection engines have a single non-direct injector in the intake manifold. So the V6 has 6 in cylinder direct injectors and one port injector. That adds complexity and is more a workaround than solution.

 

[Sayjac]

Are they using these advances in the Taurus Ecoboost engine that BG is testing? Not picking on Ford here, questions here are still regarding DI from any manufacturer.

I realize some say BG may be cooking the books on this one, but still too many questions regarding DI for me. As mentioned, down the road, perhaps the answers will be satisfactory enough for me.

 

[440Magnum]

Originally Posted By: mikered30
I thought toyota/lexus solved this issue, or at least minimized it better?


They stuck a big band-aid on it by using a central injector to "wash" the manifold and intake valves. Its about as elegant as when the Ford Powerstrokes were injecting raw diesel on the exhaust stroke in order to fuel the DPF regeneration cycle: it works (sorta) but leaves you saying "there has GOT to be a better way!"

 

[ffhdriver]

One Lexus IS350 engine uses 6 port and 6 direct injectors.