Hi,
I ve got an F20 Vauxhall gearbox and am wanting to monitor the temperature. What kind of sensor could i use? The original housing doesn't have room to put a sensor in a sensable place.
Is it posible to measure the surface temperature?
Greetz
Measure gearbox Temperature
It is possible to buy thermocouples in the form of a washer that you install under the head of a bolt or nut. Cylinder head temperature sensors are traditionally a special case of this technique. They replace the sparkplug washer.
Thermocouple (TC) outputs need to be amplified for all but special purpose loggers. R-T have the amplifiers, but not the washer type thermocouples, the last time I looked: http://www.race-technology.com/content.php?pcat=2&cat=62
This is a rather expensive solution, due to the cost of the amplifier rather than the sensor. There are kits and circuits available in the DIY electronic community...
The temperature of the outside of the housing will only be typically a few degrees cooler than the internals, assuming that there is oil in the 'box
This will be the case, even if the case is cast iron, but then the difference will be a bit more and lag behind. Heat travels through metal relatively easily. Components wet and forcibly splashed with oil transfer heat with the oil quite well too. The difficult heat transfer is between metal and air, especially if the convection that occurs at this surface is in relatively still air.
The exception to be aware of with a surface measurement is that the surface might be hotter than the internals if it is subject to a strong radiant heat source, such as an exhaust pipe. Common sense is usually a sufficient guide
I do not know the F20 or your installation. As you've observed, most general purpose screw in automotive temp sensors are rather bulky. Apart from the space issue, the size of the hole required could create a potentially disasterous reduction in strength and durability in many locations on a gearbox housing. There are smaller (1/8 NPT) sensors available if you look hard enough. The hole for these will end up over about 8mm when tapped, so the mechanical properties of the housing can still be compromised.
This is especially so, if it is a lightweight production die-cast aluminium thing run in a hot, high load, motorsport application
Thus, the TC washer solution should be explored.
If you are simply curious how hot the thing gets, forget logging and apply some self-adhesive temperature strips:https://www.demon-tweeks.co.uk/products/ProductDetail.asp?cls=MCYCLE&pcode=TDSA&cc=eur
Thermocouple (TC) outputs need to be amplified for all but special purpose loggers. R-T have the amplifiers, but not the washer type thermocouples, the last time I looked: http://www.race-technology.com/content.php?pcat=2&cat=62
This is a rather expensive solution, due to the cost of the amplifier rather than the sensor. There are kits and circuits available in the DIY electronic community...
The temperature of the outside of the housing will only be typically a few degrees cooler than the internals, assuming that there is oil in the 'box
This will be the case, even if the case is cast iron, but then the difference will be a bit more and lag behind. Heat travels through metal relatively easily. Components wet and forcibly splashed with oil transfer heat with the oil quite well too. The difficult heat transfer is between metal and air, especially if the convection that occurs at this surface is in relatively still air.
The exception to be aware of with a surface measurement is that the surface might be hotter than the internals if it is subject to a strong radiant heat source, such as an exhaust pipe. Common sense is usually a sufficient guide
I do not know the F20 or your installation. As you've observed, most general purpose screw in automotive temp sensors are rather bulky. Apart from the space issue, the size of the hole required could create a potentially disasterous reduction in strength and durability in many locations on a gearbox housing. There are smaller (1/8 NPT) sensors available if you look hard enough. The hole for these will end up over about 8mm when tapped, so the mechanical properties of the housing can still be compromised.
This is especially so, if it is a lightweight production die-cast aluminium thing run in a hot, high load, motorsport application
Thus, the TC washer solution should be explored.
If you are simply curious how hot the thing gets, forget logging and apply some self-adhesive temperature strips:https://www.demon-tweeks.co.uk/products/ProductDetail.asp?cls=MCYCLE&pcode=TDSA&cc=eurReturn to “Sensor-related questions”
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