Ignitor temperature

[bfr1992t]

This is aimed at jetjock, jdub, figgie, IJ, etc...

Has anyone monitored the case temperature of the 7MGTE ignitor? I'm checking the top of the case with an IR pyrometer calibrated to emissivity of the case (avoid the more reflective sticker). It seems to vary by about 15-20F, hottest being the center at the wire end and coolest at the other end. I'm mainly looking for average operating temp on a car with a stock ECU. Preferably drive to full heat soaked operating temp, open hood and immediately check temperature.

Thanks guys.

[figgie]

I never got around to measure the 7m ignitor assembly.

[fenix]

if you dont get an answer, i'll do it. I dont have a super "pyrometer", but i have a ir thermometer :P

I'll check it right after i pull up at work tomorrow (unless i go somewhere beforehand, i'll keep an eye here)

[grimreaper]

i dont know why the ol'timers HAVE to be the ones to answer this. why the concern with this?

[Poodles]

It's built like a heatsink for a reason...

[IJ.]

Never owned one but I know for a fact if you overdrive Bosch ignitors they vent epoxy and cease to function....

[figgie]

i dont know why the ol'timers HAVE to be the ones to answer this. why the concern with this?


Besides some of us that are always looking for hard data, who would have such precise measurements? Toyota perhaps but they are not giving that away.

[fenix]

After getting to work, I popped my hood and took some temps, it ranged from 95-112 degrees Fahrenheit, from rear to front, respectively, on wire side. On the other side it was only slightly cooler, about 90-100. Car was running, I dont know if that makes a difference.

also: 89 turbo, m/t, stock ecu.

[bfr1992t]

That is considerably cooler than what I'm reading on my car. How long is your drive to work and what was the approx. ambient temp?

After a 31 min drive, the last 8 on 25mph city roads with several stop lights: peak 183F about 1/4" in at the wire end in the middle and 169F at the other end. 77-80F ambient, probably more over the city roads at the end.

After the reverse drive home, 68-70F and the last 8mins on much cooler, 55mph roads it was max 153F at the wire end down to 140F at the other.

Looking for additional data from others...

[fenix]

30-35 mins of in city driving, 95 degree F ambient air temps.

[3p141592654]

Assuming you want to compute the mean time to failure, you want the junction temperature of the power devices. The case temp won't really tell you anything about MTTF unless you have a model from device junction to case. I got to agree with Grim, what's the point of this.

[bfr1992t]

Not looking for MTTF. I'm comparing with my ignitor and aftermarket ECU to determine if it's being overdriven.

[3p141592654]

That won't tell you if you're stressing it from a voltage standpoint.

You need to capture the waveform at the device and compare it to the device ratings. Anything else is just mickey mouse.

[bfr1992t]

Already have. I'm doublechecking.

Every device has thermal limits that are directly related to how much energy is flowing through it or how fast it is switching. We do not have the device ratings (that I know of, it's a proprietary Toyota device AFAIK) so temperature comparisons are another way.

[IJ.]

What dwell are you feeding it?

[3p141592654]

I do power amp design for a living, so don't bother explaining. You need to know breakdown voltage limits since the primary failure is going to be the flyback voltage spike when the current collapses. I highly doubt they are thermally limited. Just keep the charge current at or below stock.

Toyota does not have its own foundry. They generally use commercial parts although they may label them Denso. All the ECU power devices are commercial and you can find datasheets for them. Have you de-potted the ignitor to check?