DI Engines; Krud Fouled Intake Man'd & Intake Valves
DI Engines; Krud Fouled Intake Man'd & Intake Valves
(OP)
I've searched here in vain .. looking for forum links if they are there, or a new discussion of this problem, where substantial build-up occurs at 20-30K miles. Is this just a DI + Turbo problem, or NA DI/DGI engines also? (Gas only in this thread)
VW has a solution for 2013, using low pressure for port injection at low loads for fuel detergent cleaning.
Mazda had an unresolved problem with their 2006-2007 MazdaSpeed6.
MB just introduced DI for 2012, but their technical department is mum on the subject.
If the pic comes up, it's of a porche with DI.
Thanks, Kevin
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VW has a solution for 2013, using low pressure for port injection at low loads for fuel detergent cleaning.
Mazda had an unresolved problem with their 2006-2007 MazdaSpeed6.
MB just introduced DI for 2012, but their technical department is mum on the subject.
If the pic comes up, it's of a porche with DI.
Thanks, Kevin
.





RE: DI Engines; Krud Fouled Intake Man'd & Intake Valves
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RE: DI Engines; Krud Fouled Intake Man'd & Intake Valves
Mike Halloran
Pembroke Pines, FL, USA
RE: DI Engines; Krud Fouled Intake Man'd & Intake Valves
Some Toyota engines have been using direct injection plus port injection for some time.
I don't know why some DI engines have been trouble and others haven't, but I can think of a number of potential factors. Cam timing may have something to do with it. Avoiding reversion flow in the intake ports during overlap (or not having overlap ...) may have something to do with it. Organizing the combustion process so that under the circumstances when it is using EGR, it is not making carbon particles, may have something to do with it.
RE: DI Engines; Krud Fouled Intake Man'd & Intake Valves
I recently spoke with a DI consultant for Ford, and he inferred exactly what you spoke of. He also spoke of "special" injectors that minimized deposits.
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RE: DI Engines; Krud Fouled Intake Man'd & Intake Valves
RE: DI Engines; Krud Fouled Intake Man'd & Intake Valves
Direct injection + crankcase mist - fuel mist 'cleaning power' = mess.
I spoke with a designer a long time ago when the issues started showing themselves and he more or less stated that by the time it was clear it was a major problem, they had progressed too far and had to keep it going.
I wouldn't touch a Di petrol having looked at a lot of fouled up heads.
Keep in mind this engine requires proper tumble flow for complete combustion. Not until they add a shower type injector in the intake that comes in at higher rpm would I want one.
Some of the deposits are also from the valve stem seals weeping - just incase anyone spends £££££ designing a crank case mist separator.
The above problem was the first thing that came into my head back in 2007 when watching the video below.
http://www.youtube.com/watch?v=PqZXyHp9cPk
I think crankcase mist is just as big of a problem as egr, and baking onto said areas at shutdown.
I would think a car that spends more time at optimum rpm(lower valve seal vacuum), and one that does less short runs would escape better.
Brian,
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RE: DI Engines; Krud Fouled Intake Man'd & Intake Valves
Right now, it seems like it's just turbo'd engines ?? For the crankcase vapors, could add an oil air separator (81 924 Turbo)from crank case to air filter, and a PCV valve with a well designed catch can, with enough capacity to only require emptying at oil change intervals.
Lada Trouble, were those Mitsubishi''s turbos?
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RE: DI Engines; Krud Fouled Intake Man'd & Intake Valves
If you check the eco-boost Ford clip (no sound) it appears the DI nozzle is angled such that part of the faned spray washes the back of the intake valve. Looks good for cleaning the intake valve.
ht
RE: DI Engines; Krud Fouled Intake Man'd & Intake Valves
Your welcome for link, yours is interesting also.
I dont think people would, or like emptying catch cans. The secret of a good catch can is to keep it hot, either with bay heat, conduction, or a coolant heat exchanger. This usually means removal can be a pain.
Below is the Patent file for Audis past separator design, and possibly current too. It goes by the name of ''suction jet pump''.
http://www.freepatentsonline.com/6832603.html
It is a nice design, but, from a little r+d ive done on them, they run too cold. Reflow oil turns thick on cooling(its construction is black plastic) and gums up. If this was alloy, and bolted to head, along with drop pipe(also alloy) then Im sure this problem would vanish. These separators give a lot of trouble for this reason, I feel.
But Im not over the costing...
Brian,
RE: DI Engines; Krud Fouled Intake Man'd & Intake Valves
Brian.
RE: DI Engines; Krud Fouled Intake Man'd & Intake Valves
I read that the "2.0 R4 16v TFSI 125-199kW" turbo 4 is also FSI.
Here is a link to an FSI combustion chamber .. looks like the injector could wash the intake valves when the valve is open, either during intake or compression.
RE: DI Engines; Krud Fouled Intake Man'd & Intake Valves
RE: DI Engines; Krud Fouled Intake Man'd & Intake Valves
http
RE: DI Engines; Krud Fouled Intake Man'd & Intake Valves
Regards
Pat
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RE: DI Engines; Krud Fouled Intake Man'd & Intake Valves