Quote:
Originally Posted by kubark42
Repeatability is repeatability. I’m not a fluids expert, but I do expect that the gas station pump is accurate to beyond 0.1%.
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While that would be nice ... your a bit off.
In the U.S. the department of weights and measures for each state sets , monitors , and enforces the standards for acceptable error.
There is a sticker on the pump that indicates when that specific pump was last inspected.
The old standard was 6 cubic inches per gallon ... which was pretty good ... pumps had to be within +/- about ~2.5% ... if they were off by more than that the pump would be closed down until it passed and the operator would get fined ... most states did not fine more than about ~$500 ... but it does vary from state to state.
The new standard allot of states in the U.S. are going to now is +/- 6 cubic inches per 5 gallons ... which pushes the pumps to being +/- about ~0.5% ... it still varies from state to state... some places still use the older standards ... others have lower or higher fines etc.
But while 0.1% error rate is possible ... I do not know of any state in the U.S. that has a department of weights and measures that requires that level of accuracy.
So if a pump were off say ~50% when it was tested once per year... the owner might get fined ~$500 ...
... and have to close that specific pump until it was fixed ... but no notices or refunds to any customers... who might have been ripped off.
azcentral.com/news/articles/2008/07/01/20080701biz-gaspumps0630.html
add www in the beginning
In 2007 about ~9% of the gas pumps in Arizona failed to pass and were fined ~$300 each ... Arizona checks the pumps in the state once every ~3 years...
Quote:
A disparity of 6 cubic inches draws a citation, Meissner said. There are 231 cubic inches in a gallon.
Among some of the major offenders, according to The Arizona Republic's record search:
• Six high-flow diesel pumps at Sunmart in Ehrenberg were off from 120 to 200 cubic inches in May 2007.
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So for as long as 3 years there was a pump that was off 200 cubic inches out of 231 cubic inches ... a horrible ~86% error ... for sometime less than ~3 years ... and in Arizona pumps have a maximum fine... $5,000 if a pump is still off beyond that ... they reach the limit ... and in Arizona Operators have maximum fines as well ... and some maxed them out... and even though they were still in violation and their pumps were still inaccurate ... they were not allowed to be fined any more.
It depends on where you live ... I recommend contacting your state department of weights and measure and see what their policies are for pump accuracy ... and what kind of fines ... etc.
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Quote:
Originally Posted by RobertSmalls
Hmm, produce power until you have enough energy to coast across the finish line, leave the engine off whenever it's not required, cycle the engine off and on to keep the vehicle speed such that the engine speed is at the peak of the efficiency curve. What am I missing?
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Just keep in mind that while that may be efficient for the engine... speed fluctuations are inherently inefficient in terms of aerodynamics ... so there is eventually a break even point where the losses outweigh the benefits.
Quote:
Originally Posted by RobertSmalls
The Insight's current sensor outputs about 25mA per amp of battery current. Battery voltage varies from ~140V to ~168V at rest, and probably varies more under load. If you log both channels and consult a motor + inverter efficiency map (efficiency is a function of RPM and torque), it should be possible to estimate electric drive torque. Whether that estimate will be accurate enough to be useful, I don't know.
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FYI ... there is a fellow Gen 1 Insight driver in the U.K. who has done a fair amount with the Insight's IMA battery pack and electronics... including a BCM display for you to be able to see allot of that kinda of data.
solarvan.co.uk/index_files/Page577.htm
add www in the beginning.