I think I found the solution to DI gunk....

[exranger06]

I was going through the tool catalog at work, fiddling with the idea of adding a catch can to my PCV system, when I came across an air line lubricator. Apparently it's the exact opposite of a catch can, in that it instead of removing oil/liquids from the intake stream, it injects liquid into the intake. Some have an adjustable drip rate to adjust how much liquid gets injected. It apparently attaches the exact same way as a catch can

It seems one could eliminate the gunky buildup on direct injected engines by installing one of these on their PCV system and filling the reservoir with some kind of injector cleaner. Better yet, install both a catch can and a lubricator. Install them in a way that the catch can removes oil from the air stream before it gets to the lubricator, and then the lubricator adds cleaner to the stream before it gets to the valves.

Discuss!

 

[Eddie]

Interesting. I have read that some DI engines have an extra injector in the intake system for just problem. I can't remember the manufacture.

 

[KrisZ]

Problem is that these air line lubricators require positive air pressure to work, PCV has negative pressure.

 

[Quest]

Depending on the design of the DI gasoline engine itself: you may slow down the gunking process on the back of the intake valves by using a PCV catch can but not eliminating the buildup entirely....

Gasoline DI engine is a sage design which ideally pushes the design/efficiency boundary of a gasoline IC 4 cycle engine to a new horizon but it's not mature yet. It will require a few more years of mature in development before we can see a proper workaround or elimination of that gunky buildup on the intake valve backs.

Q.

p.s. I take the additional injector up the intake manifold as being one of a much more "viable" approach in keeping the intake valves in DI engines from gunking up. PEA additives used in regular intervals would definitely keep the problem in-check.

 

[pzev]

People have used compressed air water traps as catch cans successfully. But what you must take into account is that most DI equipped cars already have substantial PCV baffling and oil removal mechanisms. Audi's even use cyclonic oil separators, and there isn't anything better then that.

Its just a design issue with DI and US emissions requirments. Best solution I have seen so far to combat the issue is Toyota's, with extra injectors that spray the valves in low throttle situations. Their design is basically port injected and DI, using the port injectors to clean the valves. Its not ideal and is more expensive, but at least you'll have clean valves.


What they really should do is start adding inverse oiling systems to DI cars with a special injector by each port. More maintenance for the end user, but at least the valves stay clean. Would give the OEM another product to sell during service...gotta keep the oiler full .

 

[whip]

The simple solution is an alcohol injection system.

 

[SteveSRT8]

Originally Posted By: exranger06
I was going through the tool catalog at work, fiddling with the idea of adding a catch can to my PCV system, when I came across an air line lubricator. Apparently it's the exact opposite of a catch can, in that it instead of removing oil/liquids from the intake stream, it injects liquid into the intake. Some have an adjustable drip rate to adjust how much liquid gets injected. It apparently attaches the exact same way as a catch can

It seems one could eliminate the gunky buildup on direct injected engines by installing one of these on their PCV system and filling the reservoir with some kind of injector cleaner. Better yet, install both a catch can and a lubricator. Install them in a way that the catch can removes oil from the air stream before it gets to the lubricator, and then the lubricator adds cleaner to the stream before it gets to the valves.

Discuss!



Not a bad idea, you go first.

The biggest problem I see is with any modern engine the manifold is designed to be dry, as in no fuel. Thus, when you do introduce any fluids, they tend to be very poorly distributed.

 

[artificialist]

Originally Posted By: Eddie
Interesting. I have read that some DI engines have an extra injector in the intake system for just problem. I can't remember the manufacture.

Toyota has direct injection plus multi port injection in some engines.

 

[meep]

a single upstream injector... would create a lean condition on compression stroke until the D'injector was fired. would that not contribute to possible predetonation?

M

 

[ffhdriver]

There is quite a discussion, with pictures, on the VW vortex forum about the fact that catch cans don't work at all.