[kubark42]

Originally Posted by jfitzpat

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.

Again, repeatability is repeatability. We cannot comment on how members who report their fuel economy do their fill ups. It is as reasonable to suppose that they stop the first time the handle kick off as they they fill until they see the gasoline reach the filler inlet. As long as people accept 1 part-per-thousand, that’s what I’ll use. And when they no longer do, I’ll change it. You tell me about “the literature”, but for heaven’s sake, my good fellow, give me a specific citation! If the citation says +-1%, I will put that in the study instead, it makes no difference to me.

But we’re getting lost in the details. Let the experts figure out the best way to measure fuel flow, the truly interesting problems for us are in the overall structure.

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 measurement.

I don’t know, but I’m sure someone out there will figure it out and then I’ll have my answer. As problems go, there are far bigger fish to fry than this one. What about electric cars? What about hybrids?

If there’s a modeling or measuring problem, I’m certain we can overcome that when we get to it. The whole reason I’m seeking help on ecomodders is because I only have one car, so I can’t possibly test all the various possibilities.

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.

This analogy works both ways. The world is as full of stories of old men who claimed it couldn’t be done as of young men who failed trying it.

As it happens, I am also a pilot (ATP rated and CFI/CFII ticket), …

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.

Woah, slow down pardner! You’re dangerously close to the line of “assume makes an ass…” The only thing I’m saying is that I don’t like having to miss my weather window because of ice accumulation (specifically frost, but laymen reading this conversation won’t appreciate the difference as it pertains to aircraft) due to radiative heat losses on clear nights as the airplane is sitting on the tarmac. I also don’t like when condensation on control cables ices up. Kind of gets your sphincter in a tight knot when you’re at 11,000’ and you realize you don’t have ailerons anymore.

(That being said, to all those reading this, what jfitzpat said is correct down to the letter. But in the interests of scientific conversation it is not exactly relevant to the topic at hand, and I kind of wish we could delete this whole aeronautic detour through the woods. Clouds. Whatever.)

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 anecdotal 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...

First, look at it from my perspective. You are a voice on the internet. You could be a crank, or a genius. I have no way of telling. I can only judge based on data. Until you support your arguments with data and/or references, I’m stuck. It is entirely within the realm of reason that you are correct, but you’re asking me to take that on faith over what a fuel injector engineer tells me. A nebulous voice on the internet over the professional down the hall. What would you do?

But the problem is that all this is missing the point. If the error is higher, that’s fine, I just have to detune the observer a tad bit. It doesn’t really change whether I can show gains through optimal control.

Second, getting on to optimal control, who ever said that we would be driving in the area of maximum operation? That’s a big… assumption. Honestly, I can’t tell you what the optimal trajectory for your car will be. I’ve said it before, and I’ll say it again: intuition fails when it comes to optimal control. Your intuition, that you’ve gained after so many years, is standing in your way. It’s an obstruction to you seeing the overall picture.

You seem to know what you’re talking about, but I think you could contribute far more to the conversation if you responded to my questions about sources and references. I would love nothing more than to incorporate your experience into my observer and make for a better model. But what I’m getting out of you is that “I’m trying to hard to impress” and “research is going to be a stressful field”. You seem like a valuable resource, but not like this. A change of direction is in order.

Because the fact is, right now I’m engaging in a dialogue that I don’t have time for either, and that isn’t helping me. My whole theory, rather debate, with my colleagues is that it is far more interesting to engage the internet and get the experience of people who don’t necessarily read journal articles, than to go to conferences, publish in unread reviews, etc… I argue that there is a whole world of untapped cross-disciplinary experience, but we have to go to it instead of sitting on our duffs and expecting it to come to us. Right now I’m losing the battle, severely.