Vehicle Gas Consumption - Accurate?

You already answered the question, but fail to realize it:

"Lower energy content fuel will deliver fewer miles per volume, regardless of whether you're measuring it at the pump or the engine computer is measuring it at the injector."

So far so good.

Yes...

It's not "calibrated" to anything like that.

WTF?

An injector pulses X amount of gas. X times the number of injector pulses is the total gasoline used. Calculate that against the miles driven in that number of injector pulses.

This is just a fancy engine computer calculated version of the very same thing people do when they calculate their mileage at the pump based on how much gas they put in the tank and how many miles they drove since the last fillup.

The energy content of the fuel is *reflected* in the final calculation, but it is not *part* of the calculation. It used THIS much gas, and drove THAT many miles--period. Lower energy content fuel will deliver fewer miles per volume, regardless of whether you're measuring it at the pump or the engine computer is measuring it at the injector.

WTF?

The X amount of gas to which you refer will drive the piston with a force related to it's energy content. If it is E10, with a lower energy content, it will take more gas to do the same work.

My point is that Toyota doesn't know the energy content of the gas they meter, hence a small error is inevitable.

yeah, keep telling yourself that.

In the meantime, I will continue to buy specific volumes of fuel at specific prices and have that fuel propel me a specific number of miles down the road, and will be able to calculate (a) my number of miles per gallon, and (b) my fuel price per mile--

--all without knowing OR CARING about the fuel chemistry.

Again, the numbers I calculate will *reflect* the fuel chemistry, but no one needs to know the fuel chemistry in order to calculate those numbers.

Your insistence on calling that "wrong" tells me you're not paying attention.

OK, look at it this way. You buy 1 gallon of fuel A and go 50 miles. You buy 1 gallon of fuel B and go 49 miles. Oh, wait, you are right. The energy content doesn't matter.

Exactly correct--and yet meaningless to the calculation of "how many miles can I drive on X gallons of the fuel that I put in the tank".

I get a number, and yes, fuels with lower energy content will show lower numbers. As I said, the final calculated number will REFLECT the varying energy content, but the energy content itself does not factor into the calculation of the final number.

My point is that they don't have to, any more than the driver has to know the energy content of the gas as he sits in his car after filling up and calculates "I drove X miles on Y gallons of gas, I got Z miles per gallon".

That's right. And that calculated number will REFLECT the lower energy--but the calculation itself, and the final number, does not depend on knowing the energy content of the fuel.

I'll make it simple: how is a straight "I drove X miles on Y gallons of fuel, which calculates to Z miles per gallon on that tankful" calculation *wrong* because it is missing the energy content of the fuel?

It's not wrong. It's a straightforward calculation. And Toyota's engine computer is doing the exact same calculation, only at the injector pulse level.

You can't tell the world how such a straight calculation requires knowledge of the energy content of the gas, because it doesn't.

If I were able to put in a "price per gallon" figure inside the Toyota computer, it would immediately know how much an injector pulses costs--and it would be able to total up the number of injector pulses per mile and tell me how much I paid to drive that mile.

Lower energy content fuels will require more fuel delivered to make the car go the same distance. We all know that. But it's not important to the raw MPG calculation. The raw MPG calculation will, instead, show that fact.

The inaccuracy -- which was my original comment -- is in the failure to compensate for fuel chemistry/energy content.

The "inaccuracy" we're discussing is the difference between the number on the screen and the number people get by manually calculating the number of miles they drove this tank against the number of gallons of fuel they put in to fill the tank.

All sorts of things can happen to cause that discrepancy, NONE of which have anything to do with the fuel energy content.

Knock yourself out.

And yet, somehow you've managed never to explain how energy content of the fuel is involved directly in the calculation of "I put this many gallons in the tank and my odometer shows I drove this many miles".

Of course, you can't--and now you're so far underwater in your "argument," you have nowhere to go.

Your "argument" had NOTHING to do with my initial comment.

My comment was that Toyota could have easily compensated for what is apparently inherent and significant inaccuracy in its MPG measurement by compensating for fuel chemistry/energy content.

But please do continue to knock yourself silly with your line of OT ranting.

Absolutely it did.

The Toyota computer that you said "must be calibrated for some specific energy content of gasoline" is doing nothing *but* calculating specific volumes of gasoline used against miles driven.

And again, fuel chemistry/energy content has nothing to do with it.

I can drink bottled water and calculate how many bottles it takes me before I have to go to the bathroom; whether I'm sitting watching a movie munching salted popcorn or running a marathon, has nothing to do with the actual calculation.

However, the final number will *reflect* what I'm doing. But that's way, way different from calculating the number.

If I'm using a low energy gasoline, the number on the dash will reflect that the exact same way that my personal calculation at the pump will. "I drove X miles and used Y amount of this fuel, therefore I got Z miles per gallon". Z will vary as I use fuels with differing energy contents, but the calculation is the same.

Or do you dispute that?

If the dash computer differs from your personal at-the-pump calculation, which is what started all of this, many things can cause that--but that has nothing to do with the energy content of the fuel.

Ummmmm....yeah. Sure. Simple math apparently knocks you for a loop.

Stay clueless. It suits you.

Says the clueless one.

Math was never your strong suit, was it.

Indeed, it was, and far more than your command of context and relevance, shitferbrains.

...says the guy who clearly missed the entire conversation and, in an effort not to look like such an idiot, is just saying random shit.

Says the idiot whose late to the party posts define a command of random shit.

"Late to the party"?

I watched you write this, which showed you were clueless:

So you admit that everything you've written since then has been off point.