Stopping diesel engine smoke

[CloudPiercer]

There's a skill you can give to an engineer to stop smoke from appearing from the U-Boat while running diesels. Was that actually possible in real life, or is that just a game perk?

[The cursed Jäger]

You could do that in real life by NOT using the diesels. Joke aside, it's a game perk.

[kgoodwinvoodoo]

Black smoke is caused by supplying too much fuel for the air volume flowing through the engine. Fuel to air ratio is off, the engine is running rich. One could learn to keep the engine properly maintained and tuned to produce little to no smoke... and not be Rolling Coal in the Atlantic.

[Jack Schitt]

There is an additive for diesel engines that was introduced in 2010 called DEF which simply stands for Diesel Exhaust Fluid. It's a simple solution made from urea (urine). As funny as that may be it's not a joke. The urea in it is synthetic (man made) derived from ammonia and carbon dioxide.

It makes the exhaust from a diesel engine invisible or at least much less of a thick, black, puff of "smoke". How it works is DEF is filled in to a separate tank than the diesel fuel. It's not mixed in with the fuel it can't be mixed or it causes issues with the engine.
The DEF is sprayed on to the exhaust fumes inside the exhaust pipes.

When you see a non-commercial diesel powered vehicle blowing thick, black, smoke out of the exhaust it's because that person didn't fill their DEF tank.

Since DEF was only introduced 12 years ago it of course didn't exist in the World War II era this game's time period is set to. Submarines usually only ran their diesel engines when they were on the surface where they could be spotted pretty easily anyway although, yes, the smoke didn't help. They ran on battery power when they were under water.

The snorkel thing really didn't do much for them. It didn't make a whole lot of sense to be submerged and have a big, black, puff of smoke broadcasting their position. The smoke could be seen from several miles away even on clear nights that weren't overcast with clouds suffocating moonlight.

[Twelvefield]

I know you said that adding urea to diesel fuel doesn't help, but you've given me the perfect reason to piss in the tank of my brother-in-law's VW Jetta.

[Jack Schitt]

I'm not sure whether the jokes about peeing in a def tank really works or not. I never tried. The nerd reasoning for why straight urine doesn't work is because DEF is a compound. It's not just urea. Urine contains traces of urea. They're not the same thing.

If we wiz in someone's gas tank all we're really doing is diluting the fuel. We might decrease the octane but it's not going to seize the engine or clog anything in the fuel lines. The exhaust might have a weird but familiar smell.

[wolf310ii]

Originally posted by Jack Schitt:

It makes the exhaust from a diesel engine invisible or at least much less of a thick, black, puff of "smoke". How it works is DEF is filled in to a separate tank than the diesel fuel. It's not mixed in with the fuel it can't be mixed or it causes issues with the engine.
The DEF is sprayed on to the exhaust fumes inside the exhaust pipes.

When you see a non-commercial diesel powered vehicle blowing thick, black, smoke out of the exhaust it's because that person didn't fill their DEF tank.

That is pretty much BS. DEF reduces the NOx and is injectec after the katalysator, not the color or the thickness of the smoke.
If a diesel powered vehicle blows thick black smoke, comercial or not, then there is something wrong with the engine or diesel is injected directly into the hot exhaust.
Even on vintage diesel cars, the "smoke" is almost invisibe, unless the engine is cold or running under high load.

The snorkel thing really didn't do much for them. It didn't make a whole lot of sense to be submerged and have a big, black, puff of smoke broadcasting their position. The smoke could be seen from several miles away even on clear nights that weren't overcast with clouds suffocating moonlight.

U-Boats didnt "run coal" like redneck idiots, they didnt had a big black puff of smoke broadcasting their position. The smoke is thin blue-grey

[Jack Schitt]

Without DEF = Thick, dark, smoke.
With DEF = Clear.

Any idiot can see that for them selves. The BS is the nonsense you wrote.
Who said U-Boats ran coal? I didn't.

[kgoodwinvoodoo]

I might be WRONG, diesel engines do not smoke all the time they are running. There are many videos of Uboats running on their diesel engines and not emitting smoke. I drive antique diesels and I do not notice a lot of smoking on a properly maintained diesel engine. It is a interesting question.

https://www.youtube.com/watch?v=C04PjQ6zuJo

[kgoodwinvoodoo]

There's not a lot of smoking.
Does the principle apply to Uboat diesels?
https://www.youtube.com/watch?v=qlvxDcbaYV0

[Jack Schitt]

Originally posted by kgoodwinvoodoo:

I might be WRONG, diesel engines do not smoke all the time they are running. There are many videos of Uboats running on their diesel engines and not emitting smoke. I drive antique diesels and I do not notice a lot of smoking on a properly maintained diesel engine. It is a interesting question.

https://www.youtube.com/watch?v=C04PjQ6zuJo

They aren't going to blast a flume of exhaust just putting along at idle RPM. Nor is a tiny little 20 to 80 horsepower engine going to produce much smoke even if it is blasted at high RMP.
There might have only been 3 in that video that are Diesel. Most of them were gasoline. Some were coal fired Steam Engines.

I am a retired Class 8 Commercial and Industrial Diesel Mechanic. I worked on thousands of diesel engines on thousands of different diesel powered machines for over 30 years.

Do any of you attempting to discredit what I shared have comparable experience, hands-on, knowledge about them?
No? Then you don't have the experience or knowledge to argue, debate, or discredit.

If these were questions I'd be responding differently. They're not questions. I'd be glad to answer and happily do so if they were questions.

[kgoodwinvoodoo]

Arguing???????????

"It is a interesting question."
"Does the principle apply to Uboat diesels?"

[Jack Schitt]

No. That video doesn't apply, as I explained. They're barely even running at idle. Of course they're not going to be blowing a plume of exhaust. I'm digging through old pictures of engines I've worked on to share photos of real life example comparisons between an engine people see every day and a big diesel.

[kgoodwinvoodoo]

Here is Type XXI with snorkel . Not going fast enough to make smoke? Or does quality of vid not show it? Or is it really running on electric motors?

https://www.youtube.com/watch?v=SobV1yIY7t0

[kgoodwinvoodoo]

Originally posted by Jack Schitt:

There might have only been 3 in that video that are Diesel. Most of them were gasoline. Some were coal fired Steam Engines.

A comparison video, to pick out the diesels.

[Jack Schitt]

Originally posted by kgoodwinvoodoo:

Here is Type XXI with snorkel . Not going fast enough to make smoke? Or does quality of vid not show it? Or is it really running on electric motors?

https://www.youtube.com/watch?v=SobV1yIY7t0

Doesn't seem to be running very high RPM. If they were trying to be sneaky I'd assume they would be wise to the exhaust plume and keep RPM down.

Either way that video still proves my point that snorkeling didn't really help them be stealthy at all. That thing cutting through the water like that draws a persons eyes to it from a long distance away. If you were on a ship during WWII and saw that in the water would you ignore it? I sure as hell wouldn't...lol

Did you ever see something like a snake swimming in water in a big lake? You can see the commotion in the water from an extremely long distance away.