Oil Level Early Warning System

[mach4]

I've developed a custom engine monitoring system that monitors various components including fuel pressure, oil temp, boost, TIT (EGT), vacuum, transmission temp, volts, intake temp and engine bay temp. Thread here - Engine Instrumentation Project

A well documented threat to our 617/616 engines is a catastrophic loss of oil leading to zero oil pressure and, unless immediate emergency action is taken, almost certain engine destruction. The most common cause is oil cooler line failure often due to age, but also due to engine mount collapse allowing the power steering belt to cut the lines. (A partial solution to this situation is the use of steel braided lines and AN aircraft fittings.) Other causes are leaks of various sources e.g. turbo lines, loss of drain plug and so forth. A fan belt breaking can also take out the cooler lines. And in very rare cases the oil pump chain can break causing immediate oil pressure loss.

Monitoring oil pressure on the gauge is rarely sufficient to catch the problem before it's critical. Some have installed oil pressure idiot lights/buzzers in an effort to provide enough warning and time to safely get off the road and shutdown, but this is after the problem has already occurred.

I'm considering the possibility of developing an early warning system consisting of a low oil level warning light/buzzer to provide additional margin for error. It would be a simple float sensor design installed into the side of the lower oil pan and connected to a light/buzzer in the dash. In the event of a loss of oil, the alarm would provide additional time to shutdown and get off the road before strike damage occurs.

The later MB diesels have such a system and I think it warrants consideration. Many home built aircraft have similar systems to provide time to make an airport under power rather than having to put down in a field after pressure loss and resulting engine failure.

My preliminary research shows that there are easily adapted sensors that are pretty cost effective that could provide a solution.

At this point just tossing this idea out there for comment and feedback.

[moon161]

Maybe grab a 60X float sensor and idiot light, drill the 61x pan and JB weld it in.
Maybe just delete the oil cooler.

[SD Blue]

Hmm...I wonder what the float level would be with the engine running at 3-4000rpm. Using float level may be difficult to ascertain. I'm thinking a float level would be good for convenience but wouldn't it fall short for the catastrophic scenarios you mentioned?

With regards to early warning for an oil leak emergency, wouldn't pressure be a better parameter to detect?

[mach4]

Originally Posted by SD Blue

With regards to early warning for an oil leak emergency, wouldn't pressure be a better parameter to detect?

When pressure hits zero, it's too late already. The idea is to detect when oil level is dropping before it's totally empty and pressure is gone.

[dkr]

For me personally I check the oil at every fuel fill-up. If it's not coming out, it's not a slow leak.

If an oil cooler line breaks off on the freeway, I would think it would be minutes before catastrophic damage. I wonder how much of a difference this would make.

Dkr.

[dieselbenz1]

I recall reading years ago that an ultrasonic level detection device could replace your dipstick to read the actual oil level in both static and dynamic conditions.

[SD Blue]

Originally Posted by mach4

When pressure hits zero, it's too late already. The idea is to detect when oil level is dropping before it's totally empty and pressure is gone.

I wouldn't think an oil pressure of zero would be a good trigger level. However, a pressure of 1 bar might be a good place to start.

My thinking is trying to determine a "low level" on a running engine, at speed. Don't most of the low level indications on newer vehicles come into play before starting? I have'nt looked at a schematic but that would be my guess.