Re- temp Sensor

["Jim Cash" <j.cash@xxxxxxxxxxxx>]

Kevin Elmore Writes

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Subject: Temperature Sensor

I think my temperature sensor is located on the front of my car, underneath

the bumper. Does the wind make the sensor think it's colder than it actually

is? Sometimes the temp seems to change kinda fast outside, I don't know if

it's because I sped up, or if it actually got colder.

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Kevin

You are correct about the location of the outside temp sensor. It is located
there so that it can best read the temperature above the road surface - in
an attempt to detect potential freezing conditions.



But wind has nothing to do with measurement of temperature.



While it is true that wind can cause things (like human bodies) to chill
faster it is because the moving air is able to strip away heat faster -
because there is move of that cold air passing the warm surface in a given
timeframe.



But the air is not colder because it is moving (or because you are moving
through it).



The temp sensor reads the actual temp of the air it is in.  When you are
seeing changes it is because it is passing through air pockets at different
temperatures.

Just go down a slight hill and the air there will probably be cooler. Or
winds, travelling in streams and eddies will cause temperatures to vary
constantly as we drive.

So, assuming your temp reading is reasonably accurate against another
thermometer located at the same spot, while the car is sitting in a still
location (like in your garage with the engine off) then the changes you see
while moving are also reasonably accurate.

In hot weather you will get less accurate readings, but again it is
reflecting the temp above the road surface and that can be quite different
that what is generally reported on other thermometers in the area.



Hope that helps



Cheers

Jim Cash

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