Please tell me what the % humidity was prior to processing the air and after processing the air. What data can you supply to justify this process? Are you actually improving the humidity % or making it worse by introducing ambient air into an engine....or not accomplishing anything at all?
Somebody, please snake a hygrometer remote probe through some opening such as the oil filler tube on a cold engine and leave it there for a day and come back and record the measurement. Then run your dehumidifying system for a day or two and record the measurement.
Inquiring minds want to know if the data supports the practice.
Webb, I have been down the rabbit hole on crankcase humidity measurements. I too long to post and too involved, but a few well researched observations.
The capacity type humidity sensors will measure more than humidity, and the little humidor types may not even read below 20%. The EliTech units will read down near zero, but at what accuracy?? I have gone completely overkill and make a PSA dryer using 5A molecular sieve that yields 0.6% humidity or about -45F dew point. I hooked it to my engine and cleared it for about an hour. It has a humidity & temperature probe inside the dipstick tube and the EliTech will log "data" - -not sure what is humidity. That is a key - what is it measuring.
As an experiment I used a juice bottle, dryed to 1%, even heated the container while drying. Then watched the "humidity" rise from 1% to 35% in a few hours. It was empty!!! Then found out that it is PET material and it will absorb water - not adsorb, and a lot of it, so switched to a quart glass jar for the test. I used a painted lid with a build-in elastomer seal. The results of RH rise dropped dramatically, but not to zero. It would rise to about 5% in 5 hours. There is something beyond my ability to measure going on here. There is no way humidity rises in a sealed closed container made of glass. It was cleaned wiped with acetone, heated in the oven to 150F before all this testing. Now for the best part.
During an oil change some was saved for a test. After comparing the empty jar "RH" rise an oil sample - less than a cup - was put in the jar, dryed and data recorded for24hrs. It came up to around 25% RH. Maybe it has water in it? Maybe, but I called and talked to an engineer at a humid sensor company about the effect of the sensor reading oil vapor as water. It is real, and unless we have a good definition of the compounds or $1000 sensor, or both, we can not get an accurate reading on just the RH due to water. We get oil VOC measured as well.
The good news is that:
1: the rise to 25% RH in the jar mirrors data taken with the same instrument in the engine crankcase. &
2. The rise to 25, even 35% is below the critical level in the literature. The jar test and engine test for RH rise was about the same.
One may conclude from this that there is not a puddle in the crankcase system that could collect water and release it with time. I have a 1/2 Raven and my testing has given some level of confidence that it is not condensing and holding water in the container.
What is more critical in the design and application of the system is to:
1. Purge the crankcase first - while it is hot and get the combustion gasses out. Including water vapor
2. Know your instrument - don't expect it to give valid information under 20% RH.
3. Keep desiccant regenerated, especially if in cold climates where temps can drop 50-60F over a few days.
4. Use a HEPA filter on the flow line.
Caveat: There is one final physical process that could allow humidity into a closed container like the engine - that is thermal and barometric induced breathing. If anyone would like to do some calculations, please share. Otherwise I will get around to this eventually.
BTW: Here is a photo of my prototype #1 PSA system - I really like the idea of repurposing an oxygen PSA system for this function. Self regenerating!!
I ran this outside 37F, 96% RH and 10 min "warm up" period measured 0.6% RH from the dryer. 60 psi input, 20 LPM output flow. It will run on a pancake compressor.
