Water/methanol injection into the intake air is a common power/economy modification. 70/30 water/methanol is probably the most common ratio. Straight water would work.....Just would not give as much of a power boost.
I think this could be done safely with a temporary settup, but it would not be as simple as on a gas engine. The water would have to be added downstream of the turbo, to avoid damaging it. And also downstream of the intercooler if installed, to avoid pooling.
It should be done with the engine revs up, and you would need a pressure pump to inject it, since it would be on the boosted side of the turbo. I am not sure that there is ever really a reliable vacuum in the intake of a diesel.
So.......It could be done, but might not be worth the investment.
Good old timer trick on gas motors, but I'd be cautios on high compression motors like diesels. Your clearances between piston and head are much much smaller, which means less room for the water. You have a higher chance of hydrolocking.
And somehow I feel "Decarbonize a diesel" is an oxymoron. Buddy, you are never going to decarbonize a diesel motor. The moment you fire it back up after cleaning it out, the cylinders will be caked black by soot and carbon instantly. Think of all the multimillion mile diesel semi motors that were never opened up let alone decarbonized. I think you are better off spending your time running up the down escalator at the mall
The problem is not inside the cilinder, there's very little soot found there. But the intake is full of it, from where the EGR feeds into it until the intake valves. A mix of soot and oily vapours really.
Water injection seems to work to clean out the intake
Hahaha, I guess you never heard of VW's TDI engines or powerstroke, cummin,and duramax diesel engines.
TDI engines have a habit of getting their intake clogged with carbon from the egr putting exhaust gas "soot" mixing with oil vapor from the CCV port. CCV port is connect to valve cover to the intake. Bypass gasses and oil vapor is released into the intake.
On my cummin engines I have an oil catch can to help reduced the amount of oil vapor being release into my intake.
If oil vapor was not getting into the intake and mixing with the exhaust gasses "soot" why are their companies making egr delete kits to help/prevent the intake from clogging????
Water injection will keep clean you intake and combustion chamber. The water vapor
Heats up and changed to steam during the compression stroke. That steam cleans/ removes the carbon in the combustion chamber, egr valve, and intake.
Having driven through a (long) puddle, only a couple of inches deep in my Nissan, and having the flame go out, and clouds of steam from the exhaust...having traversed the turbo...I'm not in favour of dribbling water through to clean like I did/do on my petrol (gas) engines.
Can get an injector kit on Oz that introduces small volumes of unleaded, unleaded and methanol/ethanol, or ethanol/water into the intake, which could have something good like Techron added to it to clean the intakes if you needed.
Large water particles is a lot different the a fine mist of water.
I would not recommend driver in a large puddle of i knew my car had a low hanging intake I let is. I seen to many cars get hydrolock because they think they can drive in a puddle and a large amount of water get engested braking the engine.
A fine mist will never cause an engine to hydro lock not enough water to do that anyway checkout
Both are good company to ask what are the benefits if any installing a water injection system for you car.
I had looked at water/meth injection on my Cummins 6.7. Aside from the possible power increase, it was said to do a great job cleaning out the egr/ccv deposits, which is what I was wanting.
While dribbling or spraying water into the intake of a gas engine was easy, the water meth injection is a couple hundred psi. Although, I suspect in the naturally aspirated diesel would accept a very light mist into the intake.
The issue I see is that, it may clean somw carbon in the cylinder and post cylinder, it won't do much to clean the intake egr deposits. No heat, not enough pressure to make a difference.
I would like to remove intake manifold and clean manually, so i would like water to clean combustion chamber. I also have a nebulizer that produces a water mist that would assist in decarbonization. Perhaps a mist from nebulizer is finer as from spray bottle.