Russell Kent wrote:

So working on the assumption that we will eventually figure out how to
feed the engine oil from an external reservoir (rather than injecting
crankcase oil), I'd like to raise the issue of monitoring the health of
the oil injector system.  The way I see it, there are 3 possible failure
modes: pump failure, delivery failure (reservoir to pump or pump to
engine), and oil exhaustion.

IMHO, the delivery failure mode can only be adequately addressed by using
good plumbing technique: proper hoses, proper hose routing, and
positive-connection fittings (no slip-on connectors).

The pump failure mode could be detected by an oil pressure or flow
sensor, although I suspect that the pressure and flow rates are so small
that accurately measuring them would be problematic.  Anybody know how to
accurately measure oil flow rates on the order of milliliters per
minute?  I know it sounds ridiculous, but is there any possibility of a
vapor lock (or pump cavitation) issue with two-stroke oil?

Depending on the type of pump used.. a hall effect sensor feeding
data to a divide by a hundred counter driving a LED will blink a light
on the instrument panel as long as the pump is rotating. The parts cost for
this could be under ten dollars. PL

That leaves oil exhaustion, which is a pilot failure mode.  Maybe we need
a reservoir level indication in the cockpit?  Something as simple as a
"low oil" idiot light (or LED), perhaps?

Russell Kent

 
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