You are generally correct about CHTs but having a bunch of thermocouple channels on your monitor can be useful in an alternative engine installation. Being able to clamp a piece of thermocouple wire to any part of the installation (or just dangle it in the airstream behind a heat exchanger) can give you a lot of clues about how your cooling system is working. I use them to measure things like gear box temperature, under cowl temps, coolant and oil temp on the inlet or outlet that is not normally measured to see differentials and the aforementioned air temps just behind the heat exchangers. I also use one clamped where the knock sensor usually goes because that will probably be the first indication of coolant loss. The EM3 has 8 CHT & 8 EGT inputs and any of these can be used for these purposes. You can also assign 2 of them to the main coolant & oil temperature readouts if a thermocouple is easier to mount in your installation. A standard 18mm CHT thermocouple fits perfectly under the AN adapter on the oil inlet to the engine so I used that to monitor oil temp.
Temp sensors can be made from thermocouple wire by just twisting the ends together. If you have gas welding available, melt the very end of the twisted wires together for stability or crimp a butt splice over them with the insulation removed.
Tracy
Sent from my iPad I’m thinking about engine monitors and what parameters I need to watch. I’m wondering about the value of cylinder head temperatures in a water-cooled engine. For an air-cooled engine, CHT is valuable as a measure of engine overheat. For the water-cooled rotary, the coolant temp supplies that info. So, what is the additional benefit of monitoring CHTs (in addition to coolant temp). What am I missing? Gordon C. Alling, Jr., PE President acumen Engineering/Analysis, Inc. 540-786-2200 www.acumen-ea.com
|