Re: Sloth Kills Fuel Economy!

Ad absurdum per aspera wrote:
CNN has discovered something Dad taught me decades ago, after a
lifetime of putting it in practice. Easier on the machinery too.
And it jibed with what they were telling me in Driver's Ed about how
the actions of individual cars can make traffic flow better.

So with all the electronics that they put on cars for frivolous
reasons, where's the display of instantaneous and recent-average MPG
so we can actually learn rather than theorize or guess what driving
style makes our cars, with our load on our terrain, get the best
mileage? LCDs have gotten so cheap you could even do it graphically
as a function of various parameters such as throttle position if you
wanted to go deeper rather than just calibrating your neural net to
your right foot. Imagine instant feedback on how much it cost you to
cowboy it on that last hill -- or whether turtling away from a light
is saving you or costing you.

There are times out in the boonies when a calculation of best speed
for stretching maximum range out of the remaining fuel could be a very
good thing to know too.

With a fuel-injected engine under closed-loop computer control in most
cars these days, seems simple as falling off a data logger to
implement -- come to think of it, the advent of such things was about
when you saw the first built-in "trip computers." But it's never
caught on, appearing only here and there in fancy cars and a few
technoid ones that emphasize mileage such as the Prius. Given the
societal and personal-finance cost of wasting fuel, it should be a
standard-equipment secondary instrument, no?

--Joe


I'm surprised that you can't see instantaneous fuel economy on most built in trip computers; I haven't driven enough newer cars to know whether this is common or not. It'd just be a simple calculation requiring injector pulse width, fuel pressure (if it varies,) RPM, road speed, and a calibration constant (that takes into account the properties of the fuel injectors,) all of which should be available from the PCM.

nate

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