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Discussion Starter #1
It seems carbon build up on intake side of the engine has been a problem in some gas direct injection engines of past designs. I'm wondering what Ford has done to combat this issue.

For those that don't know, in the typical engine cycle the valves don't actually close at BDC of the intake stroke. They remain open slightly longer in order take in as much air as possible, which is achieved with only a small amount of blowback. After time this blowback creates a substantial carbon deposit on the intake side of the valve head. The usual engines with port injection pass fuel with added detergents over the underside of the valve heads as it enters the cylinders to clean the carbon build up away. Direct injection has no means to clean the valves that I'm aware of.
 

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I, too, wonder what Ford has done for the GDI engine in the 2012 Focus.

As for me (and I am strongly considering buying a 2012 Focus) I will plumb-in a Mann-Hummel Provent 200 (http://www.mann-hummel.com/group/upload/doc/HBCHACUaaBi.pdf). I am principally concerned about the (metered) PCV flow, where crankcase blowby gets sent back into the intake. The Focus 2012 does have an oil separator, but I don't know that it would be as effective as the Provent 200 (with its changeable filter).

It would be a PITA to plumb-in this PCV filter -- and unless it is fit with a drain arrangement, possibly with a check valve on the drain -- back to the crankcase -- above the level of the oil in the crankcase -- then the alternative is to manually drain it, at interval. I say it's a PITA to plumb-in, 'cause the space between the existing oil separator, and the point where the air-flow (exiting the separator) is plumbed back into the intake manifold -- is at a premium. I think it'd require removal of the intake manifold, to be able to make the connections / re-routes, etc...

Other cars -- notably the BMW's with GDI -- have a clear problem with carboning up, as I understand it.

Toyota has proposed GDI engines, with both piezo-type direct injectors, and also port injectors. The latter would come on once in a while, or possibly continously, although at less than the full fuel requirement for the engine. Their sole purpose would be to keep the intake valves washed in high-detergency (relatively speaking) gasoline for purposes of staving off the carbon build-up.

Your suggestion that 'cause of valve timing, the reversal of flow carbons-up the intakes -- is intriguing. I had never heard of that before. I suppose it's one of two sources?

Eurofordfan
 

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Mazdaspeed 3's have some considerable build up as well. A lot of guys when going with big turbo builds will get throttle body and intake manifold thermal insulator gaskets, and when they pull those intake mani's, the result is generally a lot of black buildup, lol.

I wonder if Ford will clean these for us at scheduled intervals to avoid the buildup. I'll atleast be asking my dealership if they will.
 

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Mazdaspeed 3's have some considerable build up as well. A lot of guys when going with big turbo builds will get throttle body and intake manifold thermal insulator gaskets, and when they pull those intake mani's, the result is generally a lot of black buildup, lol.

I wonder if Ford will clean these for us at scheduled intervals to avoid the buildup. I'll atleast be asking my dealership if they will.
I'm thinking this may be the case if it turns out carbon build up is a problem.
 

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Remember Ford doing a live tear down of their 3.5L EcoBoost at last years Detroit Auto Show?

At the Detroit Auto Show in January, Ford was confident enough about its popular 3.5 liter EcoBoost direct-injection V6 to have technicians tear down an example engine that had accumulated the equivalent of 160,000 miles through an intentionally abusive regimen of log dragging, high-speed towing and desert racing. When they opened it up before a live audience, they found some light carbon deposits on the valves and pistons, but not enough to affect performance. In fact, the engine showed a loss of just one horsepower afterwards.

Stephen Russ, technical leader for combustion for Ford’s 2-liter Duratec DI engine, said that similar to GM, engineers have determined the proper injection-timing calibration to help eliminate the carbon deposits. But Russ also said the technology of injection components – particularly the high-pressure solenoid injectors – has quickly matured, meaning excess valve deposits in most DI engines should become a thing of the past as these improved components are incorporated into production.
http://www.autoobserver.com/2011/06/direct-injection-fouls-some-early-adopters.html


http://www.ford.com/trucks/f150/experiencef150/

This link is for the Live Chat with Ford regarding the 3.5 EB tear down and what they found.
http://www.thefordstory.com/our-art...rd-v6-engine-program-manager-jim-mazuchowski/
 

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Also, another manufacturer has found that if you can keep the temperature of the intake valve down, deposits won't form on it.
 

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Discussion Starter #7
I, too, wonder what Ford has done for the GDI engine in the 2012 Focus.

As for me (and I am strongly considering buying a 2012 Focus) I will plumb-in a Mann-Hummel Provent 200 (http://www.mann-hummel.com/group/upload/doc/HBCHACUaaBi.pdf). I am principally concerned about the (metered) PCV flow, where crankcase blowby gets sent back into the intake. The Focus 2012 does have an oil separator, but I don't know that it would be as effective as the Provent 200 (with its changeable filter).

It would be a PITA to plumb-in this PCV filter -- and unless it is fit with a drain arrangement, possibly with a check valve on the drain -- back to the crankcase -- above the level of the oil in the crankcase -- then the alternative is to manually drain it, at interval. I say it's a PITA to plumb-in, 'cause the space between the existing oil separator, and the point where the air-flow (exiting the separator) is plumbed back into the intake manifold -- is at a premium. I think it'd require removal of the intake manifold, to be able to make the connections / re-routes, etc...

Other cars -- notably the BMW's with GDI -- have a clear problem with carboning up, as I understand it.

Toyota has proposed GDI engines, with both piezo-type direct injectors, and also port injectors. The latter would come on once in a while, or possibly continously, although at less than the full fuel requirement for the engine. Their sole purpose would be to keep the intake valves washed in high-detergency (relatively speaking) gasoline for purposes of staving off the carbon build-up.

Your suggestion that 'cause of valve timing, the reversal of flow carbons-up the intakes -- is intriguing. I had never heard of that before. I suppose it's one of two sources?

Eurofordfan
I've read your post a few times and I'm still having trouble understanding how you would configure the Provent with what is existing, probably because I'm not completely aware of what is existing and what is not in the Focus's system. Has the Provent been used with successful results before? Is blowby the same or similar to EGR (Exhaust Gas Recirculation)? I was not aware of blowby being a potential source of carbon build up either.


Remember Ford doing a live tear down of their 3.5L EcoBoost at last years Detroit Auto Show?

At the Detroit Auto Show in January, Ford was confident enough about its popular 3.5 liter EcoBoost direct-injection V6 to have technicians tear down an example engine that had accumulated the equivalent of 160,000 miles through an intentionally abusive regimen of log dragging, high-speed towing and desert racing. When they opened it up before a live audience, they found some light carbon deposits on the valves and pistons, but not enough to affect performance. In fact, the engine showed a loss of just one horsepower afterwards.

Stephen Russ, technical leader for combustion for Ford’s 2-liter Duratec DI engine, said that similar to GM, engineers have determined the proper injection-timing calibration to help eliminate the carbon deposits. But Russ also said the technology of injection components – particularly the high-pressure solenoid injectors – has quickly matured, meaning excess valve deposits in most DI engines should become a thing of the past as these improved components are incorporated into production.
http://www.autoobserver.com/2011/06/direct-injection-fouls-some-early-adopters.html


http://www.ford.com/trucks/f150/experiencef150/

This link is for the Live Chat with Ford regarding the 3.5 EB tear down and what they found.
http://www.thefordstory.com/our-art...rd-v6-engine-program-manager-jim-mazuchowski/

Thank you!! This was the perfect thing to sedate my fears carbon build up relating to valve timing. Although, forced induction may have been a factor that helped to keep "blowback" off the valve necks. Has Ford done a public tear-down on any non-boosted Focus engines?
 

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I've read your post a few times and I'm still having trouble understanding how you would configure the Provent with what is existing, probably because I'm not completely aware of what is existing and what is not in the Focus's system. Has the Provent been used with successful results before? Is blowby the same or similar to EGR (Exhaust Gas Recirculation)? I was not aware of blowby being a potential source of carbon build up either.





Thank you!! This was the perfect thing to sedate my fears carbon build up relating to valve timing. Although, forced induction may have been a factor that helped to keep "blowback" off the valve necks. Has Ford done a public tear-down on any non-boosted Focus engines?
Blowback was a major contender in the Mazdaspeed 3, lol, so forced-induction did nothing there... but that car has a really poorly designed PCV system, so that's Mazda's fault. Or is it Ford's? I don't know the details but I know Ford helped develop Mazda's MZR 2.3 DISI Turbo. Who knows, but if they did help design it I'm sure they've refined some things across the 5-6 years it's been since that engine debuted in the Mazdaspeed 6.
 

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DaeGoesFast: humor me for a moment... Nearest as I can tell, PCV systems have two ports into or onto an engine... The system draws clean air from downstream of the air filter, and sends it thru the pcv valve (which is a known / calibrated restriction) -- and this line ties-in to the valve cover (which is in communication with the crankcase). Then elsewhere on the block, in a portion that also is in "communication" with the pressure in the crankcase, the flow is taken thru an oil separator, which sends liquid oil back to the crankcase, and sends the vapors on to the intake manifold (where the vapors are combusted). The second line mentioned picks up (from within the crankcase) to varying degrees, engine blow-by... oil / vapor mix... aerosol oil droplets, in air, along with gasoline vapor. The overall pcv flow bypasses the throttle and bypasses the air inflow measuring device, hence the need for the pcv to restrict the flow to a known degree, i.e. create a known restriction that is compensated for, by the Powertrain Control Module (unmetered air has to be compensated-for... fuel added to, to compensate, otherwise you get a lean mixture).

In any case, the Provent would be placed in the vapor line that leaves the stock oil separator device – due to my perception that the stock oil separator (without changeable filter elements) is probably not that super in "scrubbing" the oil aerosols out of the air / gasoline vapors. The the "overhead" (or vapor flow) from the Provent would go back into the intake manifold, and the liquid drain from the Provent would go into a line which has a check valve, and then would be drained back to the block, above the oil level. I am not 100% sure about the orientation / arrangement of the check valve -- but apparently it is used in turbocharged applications, and also functions in naturally aspirated, as well, where it allows drainage only when the engine is shut off. The check valve is not a necessity. Instead, the oil flow off the bottom of the Provent can simply be terminated with a valve – and the Provent can be manually drained, at interval, into a tin can - when the engine is shut off.

This is explained, in the link to Mann Hummel provent series of oil / vapor separators, above...

Your question about its application: it certainly has been used in diesel engines. I believe it has as well been used in gasoline engine applications. The application is the same, in that diesel engines take pure air into the engine (but for combustion blow-by) – and diesel engines get coked-up intake valves. The VW TDI crowd use these Mann Hummel Provents, a fair amount, as I understand it.

I do know that all manner of people use those so-called oil catch cans.. .some of which look pretty fancy. However, some of the catch cans are absolutely empty -- and so the oil-droplet-laden vapor... well, the liquid oil does not get intercepted.... and so these plain oil catchcans are useless. The Provent has a replaceable filter element, that is designed to catch the oil aerosols.
 
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