Ford's Solution To Intake Valve Deposits w/ DI

[G-MAN]

Originally Posted By: 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!"


I disagree. I think it's a perfectly workable solution. It's the reason engines with carburetors and TBI rarely developed intake deposits even with EGR (assuming adequate detergent levels in the gasoline).

If you've got EGR and PCV filing the intake manifold runners with blowby and exhaust gases, there is no way to eliminate buildup without having some mechanism to continually wash down the interior surfaces of the intake manifold. With a carburetor or TBI, this happened from the minute the air/fuel mixture entered the manifold. With port injection, the valves got washed but the manifold interior could and often did become a mess. Now with DFI, nothing is getting washed, hence Toyota's solution.

 

[unDummy]

GDI is likely to stay until they figure out vapor fuel injection.

To sacrifice more fuel in order to keep the intake port and valve clean is going to be an interesting proposition.

Fuel reversion into the intak,e via VVT and timed fuel directly injected, when it normally usually isn't, is an interesting fix.

Hope it works and doesn't mess up MPG or emissions tuning(which will have to be adjusted for any fuel that is used to do other work other than combustion.

 

[dwendt44]

Mercury Marine uses a air/fuel Direct Injection system that shoots air in with the fuel. That's on the two stroke Optimax engines.
Don't see how that would help keep the valves clean though.

 

[Shannow]

That's the Aussie Sarich patent isn't it ?

 

[OVERKILL]

Originally Posted By: G-MAN
Originally Posted By: 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!"


I disagree. I think it's a perfectly workable solution. It's the reason engines with carburetors and TBI rarely developed intake deposits even with EGR (assuming adequate detergent levels in the gasoline).

If you've got EGR and PCV filing the intake manifold runners with blowby and exhaust gases, there is no way to eliminate buildup without having some mechanism to continually wash down the interior surfaces of the intake manifold. With a carburetor or TBI, this happened from the minute the air/fuel mixture entered the manifold. With port injection, the valves got washed but the manifold interior could and often did become a mess. Now with DFI, nothing is getting washed, hence Toyota's solution.


We don't have EGR in the intake here though. Ford is using VCT to create EGR with cam timing.

Not sure about PCV however.

 

[ffhdriver]

According to several posts I've read, the EGR is not the problem, it's the PCV gasses.

 

[mechanicx]

If that's the case, I wonder if exhaust scavenging the crankcase precat would have that big effect on emissions? Maybe using engine vacuum to scavenge at first than switch to exhaust scavenging after converter warmup would be a good compromise to keep emission and deposits down.

 

[mechtech2]

Originally Posted By: 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.


This secondary injector is what seems to be the best they can do about the problem with DI. Ford for sure was heavily involved with this.

 

[Shannow]

When mercedes was playing with Wankels, they found that a thin layer of oil wetting the inlet manifold would work it's way along the manifold, and lubricate very effectively the apex seals, without having to fill the combustion volume with a "2-stroke" mix.

The film made it's way to exactly where it needed to go.

When I did my BE thesis, the bahaviour of the wetted manifold surfaces versus the bulk air flow made them 2 entirely different actions.

I reckon that you could get enough "wet" cleaned components with minimal disruption to the benefits of D.I.

 

[440Magnum]

Originally Posted By: G-MAN
Originally Posted By: 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!"


I disagree. I think it's a perfectly workable solution.


I didn't say it isn't *workable,* I said its a kludge. Take out the port injectors in favor of direct injectors for more precise fuel metering and the ability to open up the timing map without risk of detonation.... then have to stick them back in for a cleaning cycle? How very disappointed the engineers must have been.