Differences between automotive & airplane engines

"Peter Dohm" wrote in message
...

My reasoning is that the higher average power levels in aircraft use may
keep the oxigen sensors in the exhaust system hot enough for the
inevitable
lead deposits to sublimate off as fast as they would otherwise build.

Sorry, no. If you want to run lean - then you want a wide range sensor - I
don't recall the operating temperature on those, I'm embaressed to admit,
but if you look in the holes in the protection tube, you can see the sensor
element glowing (At least the NTK brand has a hole right on the end that
lets you see the element directly - I never tried to look into a Bosch or
Denso sensor). And, if you get the sensor much hotter than the normal heated
temperature, they will be damaged and give inaccurate readings (guess how I
know.) The element temperature is actually controlled via a closed loop
controller that reacts to the measured impedance of the sensor.

The more common swicthing sensors are not as sensitive to variations in
temperature and generally don't run as hot.

If you want to put in Oxygen sensors, you are pretty much stuck with
unleaded fuel.

My
best guess is that average power levels in automotive use run around 10%
of
maximum, due to a lot of time spent idling. Even allowing for very
substantial derating, aircraft use would involve much higher power. For
example, I just drove a Plymouth Neon on a 450 mile road trip and, judging
by fuel burn, the 130 HP engine produces less than 25% power at 70 MPH (or
about 70-75% rpm).

Sounds close.

--
Geoff
The Sea Hawk at Wow Way d0t Com
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