When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I think with a bit of heat shielding, I can get the Oil Temperature Sensor to read closer to as though as it is submerged in engine oil.
When I renew my serpentine belt, pulleys & tensioner, I have to remove my aftercooler. So I might as well use the opportunity to install K themocouple based Oil Temperature Sensor to the Engine Oil Pressure Sensor adapter.
The result is not bad. Below is stationary revving of the engine, no wind speed from car movement, only from cooling radiator fan.
5Hz data
====================================
83 minutes 100+ KM test drive.
======================
What I can do for improvement is, to shield the thermocouple from ambient cooling by forced airflow for and when 100 KM/H and above.
Example is my dive compressor, since 2010 I been monitoring its cylinder heads (3) temperature.
In 2010, I did not add spade terminal to the K thermocouple ( B) for easier install using hose clamp, it was naked small wire the K thermocouple (B) is.
I then machined item A ( half moon brass ) as a touch pad to make sure thermocouple can touch the hot pipe well and read more accurately as the hose clamp C press down the K themocouple by
way of item A.
After I monitored the cylinder heads temperature, at 30C ambient, the compressor is actually undergoing mild overheating as 2nd stage cylinder head temperature passed 135C.
Same model compressor in different market, Bauer Canada has overheat temperature sensor attached to it and the overheat trigger value is 125C.
This is air cooled compressor, not water cooled.
So I then added electrical high static blower of 0.75KW to help cool down the compressor, as its own pulley fan is very low air speed of no greater than 16KM/H, while the electrical blower can do 50 KM/H at 30cm from fan blade.
This compressor is very expensive for such a small unit, about US$20,000 back in 2010. So I must not let it die from overheating or short lived by overheat.
One day I realized that the way I installed the K thermocouiple is not good, the half moon brass when blown with high speed wind from the electric blower acts as a cooling radiator, taking about 5-7C away from the thermocouple.
So I installed a fiberglass heat shield between the K thermocouple and the half moon brass and hotter/actual cylinder head temperature is now possible.
I was thinking to do the same for the W212, use heatshield to keep heat in at the K thermocouple.
The engine bay temperature 20 cm away from radiator towards engine block can be 89C at traffic jam, but much cooler at 70ish Celsius when car is moving 100 KM/H or higher so there is still
30ish C of cooling power at high speed based on 100C engine oil temperature at the skin of the adapter.
Example is the tranny oil pan temperature. I can't avoid it getting cooled down by wind force under the car at high speed. I can only insulate so much around the K thermocouple but not the whole oil pan.
You can see 4C is lost to fast airflow. If I do not insulate it well, easy 10C can be lost at high speed. In typical slow traffic jam, 77C is the normal tranny oil temperature at oil pan skin.
Differential casing is slow to heat up, due to no real heat generating activity like a tranny and it is big and heavy, so plenty of mass.
The K thermocouple is placed on its flat back facing rear bumper, so wind can't get to it much, only some turbulence.
I seen like 95C when car driven 10 hours at mix highway and rural road speed.
Per my experience, it is not just technical temperature pickup, but placement that is important too.
Doing 7G transmission in the past, I did not have scanner that would read the temperature, so used infra-red thermometer.
Depends where I pointed it on transmission, the differences were up to 20F
Infra red thermo gun is not reliable, due to emissity and depending on its spot ratio.
In fact thermal gun has the same issue, but since we can see what's happening at pixel level based on produced image, we know how to avoid it.
The tranny oil pan is very thin, so it gets to oil temperature pretty fast and even.
I have compared my thermocouple with Xentry, it is within 1-2 celcius and if we give time for oil pan to warm up from oil heat, it can match the Xentry one.
Cooling down after use, in the garage, is the easier time for thermocouple to match Xentry as it is a very slow process of temperature change.
10-01-2022, 10:56 AM
