For a 'hobby' project I'm looking for a way to measure/detect whether a diesel engine is producing (too much) smoke (carbon particles). Anyone got some idea's on how to do this reliably for a small amount of money? The required accuracy is not so high.
Gut an old photoelectric smoke detector?
John
You could go to a smog check station and ask them where they get their tailpipe probes.
Good Luck! Rich
I have been thinking in that direction, but I'm afraid the high temperature (and big temperature changes) may be a problem and the sensor might be poluted by carbon deposits.
What do lambda probes measure?
They meausure oxygen, called lambda probes because they are used to measure exhaust oxygen to control the lambda or fuel/air ratio . also called exhaust gas oxygen sensor EGO
-Lasse
Do you have an air compressor? You could make an 'air curtain' in front of the emitter and sensor. Basically, just blow a small amount of air across each aperture.
Small sheep.
That's baaaaad!
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------------------------------------------------------------------ Deja fubar: The feeling that you've made the same mistake before.
If you have three of them you can test for the exact level of nerdiness. ;-)
Compressed air is not available. I was hoping to do something with the conductivity. The smoke I'm interested in consists of carbon particles, so they must be conductive. I just don't know if its worth a try or my idea is completely nuts and optical is the way to go.
Exhaust with conductive particles in it does not become significantly electrically conductive with any particle density which could be called smoke, but you could possibly measure electrical conductivity of a patch of filter paper after drawing a fixed amount of exhaust gas through it (moisture would be a problem), or build a miniature electrostatic percipitator and measure the current drawn as the exhaust sample is drawn through it at a known rate.
For hobby use though you should probably just suck some exhaust through filter paper see how dark the spot on the paper gets. You could make reasonable comparisons between vehicles by timing how long it takes for a given spot darkness at a constant rate of suck. Or you might be able to find a cheap furnace smoke density tester on eBay or elsewhere, of the type which uses a few squeezes of a rubber bulb to suck exhaust through the filter and includes a color comparison chart.
Okay, that is a clear answer.
Hmm, that would be too slow to use as a feed-back system for the car's engine management :-)
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