Re: Air fuel ratio 02 sensors for data
Posted: Fri Sep 08, 2017 6:18 pm
If anyone is interested I have a good little used Innovate LM12 for sale, can log up to 12 wideband AFR and log other things like oil pressure, rpm, etc.
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EGTs are also a safety limit, specially with an expensive industrial engine. The actual temp depends on the engine and the fuel. Typically up at 600 deg C you'll see a 20 or so deg C variance between cylinders and maybe 150 deg across the turbo.Warp Speed wrote:And again, what are EGTs good for?
Certainly not much relating to this thread! LOL
With regard to engine temperatures, there are four possibilities.Firedome8 wrote:Would the EGT drop if the cylinder goes into Pre ignition?
Perhaps you can elaborate on what conditions cause each scenario?David Redszus wrote:With regard to engine temperatures, there are four possibilities.Firedome8 wrote:Would the EGT drop if the cylinder goes into Pre ignition?
Piston temp goes up, EGT goes up
Piston temp goes up, EGT goes down.
Piston temp goes down, EGT goes down.
Piston temp goes down, EGT goes up.
Each will result from some combination of tuning or operating conditions.
I think you'll find that if you correlate the two together(O2/EGT),you predict disaster before it happens.Belgian1979 wrote:I don't see how EGT would be able to predict pre-ignition, but maybe I can learn something.
Like I said, I think EGT's combined with WB could probably tell you more about variances in ignition timing and let you detect misfires, but I don't see more use for EGT's further than that. On the cost aspect I'm not sure it would bring additional value.
Unfortunately, with most any solid roller performance engine, there is so much engine noise, that a knock sensor becomes useless!joe 90 wrote:Coupled with a knock sensor which works.
As opposed to one which doesn't.
Hi, do you have much experience with GM's knock control strategies? I don't have a ton of experience with EFI and solid rollers but one comes to mind that worked very well. It was a pair of ~1500hp blown 571 BBC's for a boat. I spent about 3 days on the dyno just on knock control. Using a crank/cam sensors and 8 coils(sequential spark), the GM strategy allows you to listen at a programmable time before and after TDC on the compression/combustion stroke for each cylinder and ignores all other noise outside that window of time. It will also only retard the cylinder that is knocking instead of all of them at a whack.Warp Speed wrote:Unfortunately, with most any solid roller performance engine, there is so much engine noise, that a knock sensor becomes useless!joe 90 wrote:Coupled with a knock sensor which works.
As opposed to one which doesn't.
Just speculating, but preignition is in some ways similar to advancing the spark timing and so would likely result in an unexpected drop in EGTs, probably not simultaneously in all cylinders.Belgian1979 wrote:I don't see how EGT would be able to predict pre-ignition, but maybe I can learn something.
Like I said, I think EGT's combined with WB could probably tell you more about variances in ignition timing and let you detect misfires, but I don't see more use for EGT's further than that. On the cost aspect I'm not sure it would bring additional value.
That's a possibility Bill, like I said I never used EGT's so don't have much to add. I used O2's extensively though.MadBill wrote:Just speculating, but preignition is in some ways similar to advancing the spark timing and so would likely result in an unexpected drop in EGTs, probably not simultaneously in all cylinders.Belgian1979 wrote:I don't see how EGT would be able to predict pre-ignition, but maybe I can learn something.
Like I said, I think EGT's combined with WB could probably tell you more about variances in ignition timing and let you detect misfires, but I don't see more use for EGT's further than that. On the cost aspect I'm not sure it would bring additional value.
I have got a question : if you can hear valvetrain noise outside of the engine bay, why wouldn't a knock sensor not hear that noise ? After all, it's a microphone attached to the engine.joe 90 wrote:I've got a solid roller engine and a knock sensor but it's a japper.
It doesn't make much noise.
If you've got one and it DOES make lots of noise....it's built wrong.