We have an engine model which is prone to a particular problem. When the engine goes down after it fails a turbo charger, it slowly fills the aftercooler and intake manifold up with oil. When the engine shutsdown, the aftercooler drains the oil into the manifold. When a operator tries to restart the engine, the cylinders fill up with oil (only after it actually starts) then hydro locks and spits a connecting rod out the side of the block. {yes, the engine generally starts fine with no hydrolock until it starts coming up to speed, then it sucks the oil in and BAM!}
This is an industrial engine, which runs un-manned 24/7 and has a shutdown/safety panel. We have several hundred of them.
What we're looking for, is some sort of sensor that can detect presence of oil in the intake manifold. Oil can reach up to a 1/4" deep. We have a port we can screw into, now we have to determine the best way of detection.
Since oil is a pretty good insulator, it will have an affect on what type of sensor to use or design. Items we thought of....
Float style or tip level sensor - Hard to read a 1/4" level Small, low temp hot wire, measure the current, if submerged in oil it may change, vrs air/gas mixture Capacitance measurement? - Possibly the best method???
The method can not cause combustion of a combustable mixture. We have 24 vdc on skid. Normal shutdown method is to pull down inputs from our panel (3.3 vdc TTL with pull ups) grounding an input forces it low thus a fault.
Any clever ideas for this one?
Richard
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