New six cylinder engines have no dipstick

May 23, 2005 45 Replies

Everything is going map driven. The oil level sensor is a pair of electrodes in the pan that measure voltage between the pair. As the voltage drops, the oil level can be determined via map based interpolation.

Please. BMW goes from a dumb sensor to a very smart one with sensor failure detection and you want the old one?

No, it's not.

Perhaps a career change is in order to bring the unenlightened to their senses?

I'll see you on the road in your F150.

Correct, to a point. It's a capacitance measure, not resistance. Technology that's been in use on aircraft for fuel contents gauging since Britain pioneered turbojet passenger aircraft with the De-Havilland Comet. Badger.

That'll teach me to post from home.

The other interesting point is that if they fit one in 2 opposite corners and calibrate the plate areas correctly, the gauge/indicator will always read true regardless of attitude. Again, this is why aircraft fuel gauges don't vary with changes in attitude. Modern senders use 2 concentric tubes as the capacitance plates, the tubes being shaped to vary the distance between then according to the shape of the tanks at that point, to ensure a true and accurate reading. Incorporated within the tubes are thermistors that give either a "wet" or "dry" reading, to control the likes of low level warnings and fill shut-off valves. The technology ain't new, if I can suss out the character map I'll post the formula for working out the capacitance, which demonstrates the plate gaps/areas theory nicely. Badger.

Couldn't suss out character map in outlook express, so here goes anyway!

C = Uo Ur A --------- d

C = (capacitance, farads) Uo = relative permeability of air Ur = relative permeability of any other substance between plates A = cross-sectional area of plates d = distance between plates

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