Direct Injection - oil additive question solution?

[DriveHard]

It seems that there is some discussion that MMO and like products can evaporate off quite quickly when added to the oil. It is often warned to check the oil level more often when using these products to be sure you do not run low on oil. Where does this oil go? Past the rings...out the seals...perhaps, but my guess is that most of it is evaporated and burned up in combustion through the PCV valve.

So my question...could a volitile oil additive be formulated that would evaporate in the crank case, yet when ingested through the PCV valve help to keep the intake valves of a direct injection engine clean? Yup, you would have to watch your oil level...and add this product on a routine basis...but if it kept my intake valves clean, it would be well worth it IMHO.

Please discuss...

 

[Boomer]

DriveHard, I think you are on the right track. I suggested on this board actually having a separate container with an additive that would be brought up through the PCV system and flow over the valves but it was not well received. I know the major engine folks are trying to get at this with valve timing, spark timing , etc but right now I would NOT by a DI gas engine until this gets resolved.

 

[Quest]

high volatility crankcase lubricant or additives, IMHO, is not the proper way to go RE: eradicating/reducing intake valve deposits on recently released DI gasoline engines.

In fact: I personally don't think there is a proper way to overcome that fundamental issues unless engine manufacturers come out with a rather radical changes in design (changes in cam timing, etc.), and/or to include a small passive ported fuel injector upstream (on the intake side) to squirt PEA-doped gasoline to keep the deposits at bay.

Don't just casually throw yourself in the buying RE: UCL or MMO and the likes. Technology has changed so much over the decades that some stuff deemed obsolete at the end of thei product design (bowing to the need of the public/progress in the relevant field).

Me thinks that if I have to do so much (add additional UCL, or create a custom catchcan, etc. in order to run a newly acquired DI based gasoline engine in order to keep the intake valve deposits at-bay), then I'd rather get an older, proven design such as ported FI engines and stay on it for as long as possible.

My 2c's worth.

q.

 

[JHZR2]

I believe the PCV-type injection of cleaner is a smart way to go. More specifically, something that can survive combustion and make its way through the PCV to provide cleaning... yet, be easily catalyzed to prevent excess HC emissions.

That is a tough thing, thus IMO the inverse oiler, or some kind of a PCV-injection is the way to go... Either via fuel, some additive, etc.

 

[gathermewool]

I wonder if something like adding a port injector would work, with the direct injector providing the majority of the flow, and the port injector enough to maintain the valves clean. No reservoir, no special adds, just fuel.

That, in combination with maybe a redesigned PCV system with some sort of cyclone separator - though that might cause issues with moisture buildup and retention in the sump. Hmmm

 

[Quest]

@gathermewool:

It defies the call for buying a manufactured DI engine if we have to resort to elaborately adding "add-ons" such as ported FI, additional fuel-rail (DI fuel rails typically runs higher pressure than that of a ported FI requires, thus the call for separate fuel rail and fuel pump), pump, alterations to the ignition and fuel injector mapping, etc. in order to overcome the DI intake valve deposit issues.

Methinks that this task should fall into manufacturer's R&D team and not on us. We, as consumer, should be able to purchase a product, enjoy it, w/o making alterations.

Q.

 

[demarpaint]

Originally Posted By: Quest
@gathermewool:

It defies the call for buying a manufactured DI engine if we have to resort to elaborately adding "add-ons" such as ported FI, additional fuel-rail (DI fuel rails typically runs higher pressure than that of a ported FI requires, thus the call for separate fuel rail and fuel pump), pump, alterations to the ignition and fuel injector mapping, etc. in order to overcome the DI intake valve deposit issues.

Methinks that this task should fall into manufacturer's R&D team and not on us. We, as consumer, should be able to purchase a product, enjoy it, w/o making alterations.

Q.


+1 I still think DI is a problem in search of a solution.

 

[Loobed]

What causes the valves to carbon up in a DI engine? Aren't the large diesel truck and tractor engines DI? They don't seem to have a problem.

 

[mechtech2]

Ford and others are testing upstream injectors in conjunction with the DI system, to fix the valve deposit issues.
Think they know there is a problem? it ain't right yet!

 

[Quest]

Originally Posted By: Loobed


What causes the valves to carbon up in a DI engine? Aren't the large diesel truck and tractor engines DI? They don't seem to have a problem.


My understanding so far has to do with the following 2 main culprits:

(1 ) PCV system (re-routing crankcase fumes into the intake track for "re-combustion" for emission purposes) introduces oily gas vapour that would form/burned into carbon deposits on the back side of intake valves.

(2 ) aggressivbe timing/intake valve overlapping which *may introduce oily vapours (or unburned gas fumes) into the back side of intake valves.


While similar technologies have been used with excellent outcome in Diesel engines in the past for a long time, my take is that given the low flashpoint on gasoline (thus the added volatility it comes along part part of the basic properties),which may futher exacerbates the depositing of intake valves on DI gasoline engine ...

Q.
Q.

 

[DriveHard]

Perhaps I need to make an addition to my question.

Yes, this is NOT a cure for the direct injection problem for the future...I agree 100%. These engines should not be out there with the problems they have.

This is a band-aid for those of us that already have a DI engine.

The truth is, products get released all the time that need band-aids to work in the real world. This is just one of those cases. I do like my DI car, and would like to keep it. I am just trying to think of things that would get rid of one of my "pains" with this engine.

Thanks!

 

[gathermewool]

Originally Posted By: Quest
@gathermewool:

It defies the call for buying a manufactured DI engine if we have to resort to elaborately adding "add-ons" such as ported FI, additional fuel-rail (DI fuel rails typically runs higher pressure than that of a ported FI requires, thus the call for separate fuel rail and fuel pump), pump, alterations to the ignition and fuel injector mapping, etc. in order to overcome the DI intake valve deposit issues.

Methinks that this task should fall into manufacturer's R&D team and not on us. We, as consumer, should be able to purchase a product, enjoy it, w/o making alterations.

Q.


DI allows for further tuning for fueling, but that doesn't mean there couldn't be a secondary port injection system. A secondary fuel rail would need to be added, sure, but not necessarily a lower pressure pump and fuel lines. Would not a reducer (FPR) work for maintaining the secondary fuel rails at a sufficiently low pressure.

Besides, how much fuel would really need to be port-injected to maintain the valves clean?

Besides the added cost of the hardware, I wonder how something like this would affect fuel economy? Would there be any other instances (besides cleaning) where a smaller port injector injecting an initial charge during the suction stroke would be beneficial?

 

[JHZR2]

+1. Im sure there is a simpler way to reduce gas pressure on that line. Im also sure that there is a lift pump prior to the HPFP, and if that was tuned to have "typical" (non DI) pressure to send to the HPFP, there would be no new equipment besides the length of tubing and the injector.

The spare injection device might not even need to run all the time. Like diesel particulate filters go through a burn off mode every now and again, this may work, say, at cold start and every so often given certain conditions.

Cars have had cold start injectors, dont see how this would be any different...

My issue is how one would get gas to be sprayed onto all the intake valves...

 

[demarpaint]

Originally Posted By: gathermewool
Originally Posted By: Quest
@gathermewool:

It defies the call for buying a manufactured DI engine if we have to resort to elaborately adding "add-ons" such as ported FI, additional fuel-rail (DI fuel rails typically runs higher pressure than that of a ported FI requires, thus the call for separate fuel rail and fuel pump), pump, alterations to the ignition and fuel injector mapping, etc. in order to overcome the DI intake valve deposit issues.

Methinks that this task should fall into manufacturer's R&D team and not on us. We, as consumer, should be able to purchase a product, enjoy it, w/o making alterations.

Q.


DI allows for further tuning for fueling, but that doesn't mean there couldn't be a secondary port injection system. A secondary fuel rail would need to be added, sure, but not necessarily a lower pressure pump and fuel lines. Would not a reducer (FPR) work for maintaining the secondary fuel rails at a sufficiently low pressure.

Besides, how much fuel would really need to be port-injected to maintain the valves clean?

Besides the added cost of the hardware, I wonder how something like this would affect fuel economy? Would there be any other instances (besides cleaning) where a smaller port injector injecting an initial charge during the suction stroke would be beneficial?


Would a secondary port injection system on a DI engine make the fuel dilution problems even worse?

 

[Ursae_Majoris]

I thought that Toyota was already adding a port injector in their DI engines, or is my recollection off?