Message-ID: <4C422274.9000808@windstream.net>
Date: Sat, 17 Jul 2010 17:36:52 -0400
From: Carl Denk <cdenk@windstream.net>
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To: "Microcontroller discussion list - Public." <piclist@mit.edu>
Subject: Re: [OT] Is speeding logical?
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The chart concurs with what I said, but we know little about those 
vehicles, power/weight, gearing (Overdrive, gear ratios, power/torque 
curves, frontal area, drag coefficients, driving style, wind 
speed/direction), and the list could go on and on. The 
instantaneous/trip MPG is one of the most referred to gauge on the 
vehicle. On cruise at say 60 mph,fairly level road, You can see any 
where between 20 - 50 MPG with an average of 30 MPG within a half mile 
as the road slope is up and down slightly, and this is without shifting 
out of OD or the converter clutch disengaging. The readout is also very 
good for assessing engine conditions. We travel frequently Cleveland to 
Atlanta 650 miles. Fuel mileage was low by 20% and then the last tankful 
was back to normal, but returned a week later. Took some months to find 
the problem. One of the differential pressure sensors had developed a 
drop of water in a small (pea sized) foam filter that was obstructing 
the flow. It took many months for the problem to become bad enough to 
set the check engine light and a PID code. The sensor was just slow to 
provide the correct pressure reading. The computer understood different 
operating conditions and the fuel trim was set wrong.

>> Energy per time aka power is thus proportional to the cube of speed,
>> all else being equal.
>> Carl's Cougar shows that all else isn't equal :-).
>>
>> Even if it were, reduced trip time at increased speed makes Harold's
>> Harol'd square law correct for absolute energy trequired and thus fuel
>> required.
>>
>>
>>      
>    
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