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%. Otherwise, they’re making 0.1% on every liter they sell (after all, they’d be stupid to do anything other than have their pumps be at the absolute limit of the law). So if people see +-0.1% on multiple fuel-ups, that’s a strong indicator that they’re on to something.
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I could write a long post about this paragraph alone, but you do see the problem, repeatability, you just missed the application. People here are testing their accuracy against *fillups*. We do not see inside our tanks, so we are relying on a pressure system to kick off before we pour gasoline on the ground.
Do you really think that point is being hit with a high degree of precision?
However, you are actually wrong even in your disbelief. A 15 degF change in fuel temperature makes about a 1% difference in volume with gasoline. The fuel at a station is generally stored in an underground tank, so it's temp doesn't change all that much, but the fuel lines between the tank and the nozzle do. When consumer reports tested morning fillups vs. afternoon fillups, they saw about a .1% change in fuel economy. Edmunds found higher, but over a hotter period of days.
That, by the way, is a clue for one of the reasons that I find your flow accuracy claim dubious when matched to other literature.
Quote:
Originally Posted by kubark42
By measuring current, instead of voltage, we can do the same on peak-hold as we do on saturation injectors.
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Not if they are under modern PWM control. I wish I had a graphic of a typical schematic handy, it would be interesting just where you expect to put your current measurment.
Quote:
Originally Posted by kubark42
I am a small plane pilot, and I do love cold days, and cold, clear nights even better. (Just so long as there’s no ice accumulation due to radiative heat loss). But you comparison is unfair. You’re assuming that we claim that the summer efficiency map is the same as the winter efficiency map. Not so.
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I think that this one paragraph is a perfect metaphore for ths conversation. There is no assumption in my comment on what you can and cannot measure in winter. There is only a verifiable example to back up my point -
that there is a difference between engine efficiency and operational efficiency, and the difference varies depending upon application.
The only assumption that I am making is that you are young, and you are trying too hard.
I am old, so I have little patience for this sort of game. Look at your comments about flying. Private Pilot or not, you are still trying too hard to impress.
As it happens, I am also a pilot (ATP rated and CFI/CFII ticket), there are two essential ingredients for icing with a small aircraft, visible moisture and below freezing temperatures. The temps do not have to be around the plane, water droplets can get supercooled high in a thunderstorm and fall on you. But both elements have to be present (it's actually a question in both the private and instrument written test question blocks)
The suggestion that you can be out in clear, below freezing air and experience a dangerous accumulation of icing in flight is patently false. Cold clear air contains very little moisture and sublimation cannot occur under a boundary layer of 100 kt air.
NOTE for any lurking pilots, this does not mean you should ignore frost in your preflight, accumulated frost can have a fairly significant impact on lift. No, you almost certaintly wouldn't fall from the sky, but you may find your deptarture shorter on runway or a lot closer to obstacles than you wish to be - so take a few minutes and properly deice it. AOPA's Air Safety Foundation has a good online course on this.
Now, aside from establishing that you don't seem to know what the FAA would like you to know about icing, what has this accomplished? Nothing.
Likewise, what possible reason could I care about the job title of a nameless person that annecotally supports a claim? Does that meaningfully compete against accurate measurement? If so, then what does it mean that I am (truthfully) part of the team that was recently awarded the SAE/MIT Best Innovate award for green/efficiency automotive technology? Does that suddenly make your friend wrong, or do we have to go into a runoff where we measure lab coat stains or count pens in our pocket protectors?
All this sort of noise does is distract from meaningful dialog. Aside from the surprisingly fierce battle between annecdotal opinion and the existing published literature on precisely measured performance of fuel systems, I'm really making only two very simple, (and I would think) easily understood points.
1. If you print your figure 6 and figure 7 on transparency in matching scales and lay one on the other, redish color on one will fall on blueish on the other.
2. It is not really practical to maximize operation of a car at the center of the red zone - since it essentially identifies peak torque.
That's it, take it, leave it, deny it, circular file it, whatever...
I sincerely hope you continue with your studies, but if you are this fierce about annecdote vs. prior art, research is going to be a very stressful field for you!
Good Luck
-jjf