Öl-Wasser-Gemsich im Ladeluftsystem | Posts 16+

I'm not sure if a PD engine also has a silencer located before the intercooler, like my ALH does. The oil I found in my silencer was also a grayish mixture that looked more like an emulsion than pure engine oil. After cleaning the silencer, I checked the air passage. The hoses only had a normal oil film, with no trace of water. If your PD engine also has something like this, maybe verschandeln it and then observe it again. The shock absorber in my car was quite full.

Hi,

When you examine the issue of condensation more closely, it becomes quite plausible. Compared to the charge air, the inner surface of the intercooler is significantly colder due to the extremely cold airflow passing over it. When there is sufficient humidity, a certain amount of moisture will condense at the coldest point in the system, which is the liquid-cooled component (LLC).

From the inlet to the outlet of the liquid cooling system, a significant temperature difference may exist. The air flowing through at high speed is cooled by several tens of degrees in fractions of a second. Why shouldn't condensation occur? In almost all cases, there is enough humidity in the air if the surfaces are only cold enough. At significantly higher temperatures in the summer, the difference becomes smaller due to the decreasing efficiency of the air conditioning system, and the tendency for condensation decreases.

Considering the vast air masses that travel thousands of kilometers due to the jet stream, a few drops of rain are certainly plausible. I think that, at the very latest, during a longer AB run with significant boost pressure and a correspondingly high LLT, the water will come out of the system .

Dew point:
http://de.wikipedia.org/wiki/Taupunkt

Hello Roger,
The coldest point in a liquid cooling system cannot be colder than the ambient air temperature.
The warm, compressed air behind the ATL is easily 50 degrees Celsius or more, significantly warmer than the surrounding air, and is therefore 'relatively' quite dry. Condensation can therefore theoretically only occur during a longer 'sea breeze' journey, but should then disappear relatively quickly under 'normal' weather conditions. However, if the water droplets are 'underneath' the oil, they should only be able to evaporate very poorly.
Best regards,
Günther.

Hello Günther,

Of course, the air in the charge air cooling system will become warm, even exceeding 50 degrees Celsius. However, the moisture already present in the intake air cannot be removed from the system. Warm air can simply hold more moisture than cold air. This doesn't change the fundamental moisture content of the intake air (apart from the density change due to the warming and the pressure increase). And when the air, after being warmed by the turbocharger, is cooled down very rapidly in the charge air cooler, the moisture precipitates out. In my opinion, the extremely high cooling rate also plays a role. We are talking about extremely small quantities in relation to the mass of air in motion...

What does the physicist in you say about that?

Hello Roger,
The air coming out of the low-temperature cooling system is definitely going to be 40 degrees warmer than the ambient air.
It's extremely dry (relatively).
Therefore, condensation should occur only minimally, and only intermittently.
I think the amount of water 'generated' in the process is likely to be 'negligible.'
Best regards,
Günther.

Quote:

The air coming out of the LLK (low-temperature cooling) system is definitely 40 degrees warmer than the ambient air.

Nope!

My 1Z has an intake air temperature that is 3-30 K (differences are given in Kelvin) higher than the ambient air temperature.
(the few K, of course, only occur in the de facto suction mode under low load).


It's probably also due to the relatively low boost pressure, especially compared to the ARL.

m;

Roger wrote:

And if, after being heated by the compressor in the low-pressure circuit, the air is cooled down very strongly again, moisture precipitates out.

Hi Roger,

Basically, water can only condense if the air is cooled down "below its original temperature," meaning below the value of the ambient temperature.
It will never be achieved by the LLK. Therefore, no amount of water can condense in the LLK from gas that has been drawn in.
What could potentially condense is additional water from the hot CBM gases. The amount of water introduced enriches the intake air, and when it is then cooled, condensation could occur even at temperatures above ambient temperature.

What we haven't considered so far is the saturation behavior of compressed air.
If the pressure increase and subsequent cooling back to (almost) the initial temperature were to cause an "outgassing" effect in the air would, it could explain the phenomenon.
It's purely speculative -> where are the real physicists?

Thank you in advance for your contributions.

@ Günther
Yes, the oil has mixed into a grayish emulsion.

Hello,
I think this 'oil emulsion' is mainly composed of condensed exhaust gases from the crankcase and a little bit of oil leakage from the Automatic Transmission. I wouldn't worry too much about it.
Best regards,
Günther.