cylinder head temperature sensor

[squeakie]

I wonder if anyone has used something like this with megasquirt:

https://www.denniskirk.com/cylinder-hea ... 408514.sku

I am thinking about giving it a go, but if it just won't work, I'll skip it.

Thanks!

[Bruce.m]

Mario does one that should do the job.

[luftvagon]

Looks cool, but I wonder if there would be any interference coming from the spark plugs.

[Dale M.]

Some how I can't get enthused about a CHT that goes around spark plug.... I thing something that bolts/screws to head would be more practical and better sensing...

Maybe something like this in concept...



http://www.digikey.com/product-detail/e ... ND/2239473

http://www.omega.com/pptst/WT.html

http://www.omega.com/pptst/WT-HD.html

Dale

[MarioVelotta]

Some how I can't get enthused about a CHT that goes around spark plug.... I thing something that bolts/screws to head would be more practical and better sensing...

Dale

Just like what I make

[Piledriver]

Thermistor based temp sensors tend to die quickly at under-the-plug CHT temps (esp on T1s)
Common K type thermocouples are also used for EGT... The exposed/fast ones have a finite lifetime due to contamination/migration, but they last awhile and do what they need to do.

Under the plug is harder to do on T4s, as the plug seat is recessed, some work and JBWeld is required if it's ever to survive a plug change.

I personally suspect the intake port wall past the injector or even intake valve temp is probably a more ideal driver of WUE.
(That's what most drives fuel vaporization in my understanding of port fuel injection)
I have been considering trying a tiny (10/32 w/ 1/4" hex IIRC) flush mounted PTC screwed into the backside of the intake ports from the bottom of the head, under the rocker box, about an inch above the valve seat.

[MarioVelotta]

Yes, this is a thermistor but I'm not trying to get under the plug with it. But it does track my under plug thermocouple by about 50%.

[andy198712]

When's your next run of them due? Does it react at a similar speed?

[Dale M.]

Let me see if I have this right.... MS CHT is just to let ECU know when transition from a "cold" engine to a "warm" engines happens so it can throttle back idle speed and fuel values to warm parameters.... IT does not need to know exact temperature of head to control fuel volume...

If so about any "temperature" sensor setup that can be calibrated from "cold" to "warm" that the ECU is electrically capable of understanding (compatibility) is all that is required...

Only other issue may be where sensor is locate, as to how long it takes to "warm"...

Dale

[Vee Dub Nut]

Let me see if I have this right.... MS CHT is just to let ECU know when transition from a "cold" engine to a "warm" engines happens so it can throttle back idle speed and fuel values to warm parameters.... IT does not need to know exact temperature of head to control fuel volume...

If so about any "temperature" sensor setup that can be calibrated from "cold" to "warm" that the ECU is electrically capable of understanding (compatibility) is all that is required...

Only other issue may be where sensor is locate, as to how long it takes to "warm"...

Dale

Just to clarify, MS needs a COOLANT (CLT) temp measurement to know how to transition fueling from cold to warm. It does NOT need CHT, but CHT or something similar is the most logical "coolant" parameter or measure of how warm an air cooled engine is. Just wanted to make sure that folks are not getting confused about what MS really needs.

Yes, any temperature can be setup and made to work so long as it tracks the actual engine warmup profile. You then just set up your WUE based on that profile for whatever your engine needs. I've used a sensor mounted into the valve cover twice, and have also used oil sump temperature for the CLT input. Both had their ups and downs. My next build will be using Mario's trick little sensors, as I think it will be an improvement in control.

[pdub]

I think you understand it correctly Dale. After ASE and WUE have done their thing the engine temp is not longer factored into the fueling/timing, at least for MS2. Of course the IAT sensor can be used to pull or add timing...

[Piledriver]

I also use WUE to add fuel% at hot idle sitting in traffic etc.
(it's only off at 100%)
Make sure you have the extended CLT option enabled if aircooled, that's what it's for.
It allows you to use the full temp range.

[Dale M.]

Ok... Got it, just used wrong term...

Dale

[ps2375]

MS also factors CLT and AIT into fuel calcs when using speed/density. Hence the density part. But if you have some sort of temp sender in the mix, it should be able compensate in both the WUE and normal running modes. I'm sure if a motor is tuned with a certain type/location of a sensor is used then moved/changed, a re-tune would certainly be required.