Bad mpg?

[Antonm]

P

Based on this comment I can tell you are willfully ignoring what is an obvious fact.

This is just like the other thread on disablers where RG23RST handed you the facts on a platter and you still wouldn’t concede the point.

If you are so brazen as to look at a valid algebraic rearrangement of a formula and impudently refuse to see an obvious correlation, there is no point in continuing the discussion.

I can’t make it any simpler.

You also can't make true either.

Here's a statement I will stand by,,, You are a clueless moron, you like troll, and its freaking hilarious watching you grasp at straws and make things up.

Its almost like watching a political debate were the crazies just make up/ say whatever dumb crap they want that makes no sense. But this is funnier because hopefully you're not in charge of making policy/ law like the clueless politicians.
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[Antonm]

Sure did and supports the notion that larger displacement can achieve higher fuel mileage in some situations.

Thanks for agreeing.

The other slides show how VE changes things as well.

Key point there is that Ve isn’t just a function of engine dimensions ( your claim)

But I’ll leave that one alone .

The argument was you keep wrongfully saying that engines of different displacements can't make the same power at the same AFR. Remember the statement you stand by even though you accidently deleted it.

The only thing, repeat, the one and only thing, that could make a larger engine use less fuel than a smaller engine moving the same mass at the same rare would be if the larger engine happened to be more efficient at that given load than the smaller engine.

Considering both the 5.3 and 6.2 are very similar in design, i would expect their efficiencies' to also be very similar, any differences would likely be in the second significant digit range, and could go either way.
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[blanchard7684]

The argument was you keep wrongfully saying that engines of different displacements can't make the same power at the same AFR. Remember the statement you stand by even though you accidently deleted it.

The formula we have been dissecting literally says this in plain mathematics.

 

[Antonm]

The formula we have been dissecting literally says this in plain mathematics.

Again , no its does not, you just keep imagining, or misunderstanding, or wishing, or whatever that it does.

If that were true, then the solution to getting more MPG would be for everyone to drive huge displacement engines with as many cylinders as possible.

If the math says what you think it does (which it doesn't, but lets just say), and bigger meant better fuel economy, then were does it end , if 6.2L better why 8.0L or 11.0L or 22.0L, do you think all those would get better fuel milage too,,,or does that just sound ridiculous (like the other stuff you been posting?
...

 

[blanchard7684]

You also can't make true either.

Here's a statement I will stand by,,, You are a clueless moron, you like troll, and its freaking hilarious watching you grasp at straws and make things up.

Its almost like watching a political debate were the crazies just make up/ say whatever dumb crap they want that makes no sense. But this is funnier because hopefully you're not in charge of making policy/ law like the clueless politicians.
..

Look..

I can tell this is all new information for you.

It isn’t for me.

I am a practitioner of this information on a regular basis.

I found open source material (that I already knew) and provided it for discussion and your edification.

I can’t post IP.

I will make an apology for being prickly up thread.

However you have kept up incessant ad hominem, insults to my intelligence, mental well being, academic achievement, and others. Some were actually amusing and funny.

Yet I’ve kept this discussion factual. I’ve spent an inordinate amount of time attempting to educate you.

I can tell you have a hang up about this discussion.

That is ok.

Take some time and regroup.

I’m ok. You are ok.

Even though you have lobbed some nasty comments in my direction I don’t hold it against you.

This isn’t 101 level stuff. If it was,then oem’s like Gm wouldn’t have an army of engineers working these engines.

Cheers

 

[blanchard7684]

Again , no its does not, you just keep imagining, or misunderstanding, or wishing, or whatever that it does.

If that were true, then the solution to getting more MPG would be for everyone to drive huge displacement engines with as many cylinders as possible.

If the math says what you think it does (which it doesn't, but lets just say), and bigger meant better fuel economy, then were does it end , if 6.2L better why 8.0L or 11.0L or 22.0L, do you think all those would get better fuel milage too,,,or does that just sound ridiculous (like the other stuff you been posting?
...

Reductio ad absurdum

The difference we are looking for is in a small range of fuel economy.

You are plenty smart enough to know that if one of these variables goes way up then it will change the output of the dependent variable.

No where have I said that the 6.2 gets better economy in all possible driving scenarios.

There is a specific set of conditions that it can.

 

[Antonm]

Look..

I can tell this is all new information for you.

It isn’t for me.

I am a practitioner of this information on a regular basis.

I found open source material (that I already knew) and provided it for discussion and your edification.

I can’t post IP.

I will make an apology for being prickly up thread.

However you have kept up incessant ad hominem, insults to my intelligence, mental well being, academic achievement, and others. Some were actually amusing and funny.

Yet I’ve kept this discussion factual. I’ve spent an inordinate amount of time attempting to educate you.

I can tell you have a hang up about this discussion.

That is ok.

Take some time and regroup.

I’m ok. You are ok.

Even though you have lobbed some nasty comments in my direction I don’t hold it against you.

This isn’t 101 level stuff. If it was,then oem’s like Gm wouldn’t have an army of engineers working these engines.

Cheers

If you are a "practitioner" then you need more practice (like a lot more), because you have some very basic concepts and math fundamentals wrong.

There was a time back in the early 2000's where I taught math and physics to young adults, this discussion has reminded me of some of my more ,,, interesting,, students and how some people refuse to accept when they're mistaken.

But cheers to you as well, this has at least made the last few days less boring if nothing else.
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[djnice]

Entertaining. I don't have time to read it all today. Did you factor the 6.2 has higher compression?

 

[blanchard7684]

The half point in CR would benefit the 6.2. The otto cycle thermal efficiency is highly dependent on compression ratio:

3.5 The Internal combustion engine (Otto Cycle)

3.5 The Internal combustion engine (Otto Cycle)

web.mit.edu

r is compression ratio, and gamma exponent is ratio of specific heats for air (Otto cycle is an "air-standard" thermodynamic cycle for SI 4 stroke engines on gasoline)

 

[blanchard7684]

UM, no , not even close.

Lets review. Your linked power equation shows that power is equal to a bunch of efficiencies (slide of terms coming up if needed) and fuel flow.

The red box terms in the the numerator of the the mass flowrate of fuel equation are in the numerator of the power equation, and the blue boxed terms in the denominator of the mass fuel flowrate equation and in the denotator of the power equation.

For ease of reference, lets compare the terms in the red and blue colored boxes to each other, respective colored box,,, spoiler alert,,they're the same.


View attachment 447618


So that leaves these terms in the numerator of the power equation( that you linked).

View attachment 447619

So lets examine what those remaining terms in that numerator are again;

View attachment 447620

Its a bunch of efficiency terms and another fuel term,,,so your power equation says power is equal to the various efficiencies, times a fuel heating term, times fuel mass flowrate.

So, if you change any one of the terms in either the red or blue boxes, you also change the mass flowrate of fuel,,,you know fuel,,,where the power comes from.
...

Let's examine this a bit further.

Taking this view, we can further rearrange the power formula: P = n x Q x fuel flow rate.

The opposing contention is: if power is the same then fuel flow rate has to be the same. Therefore 6.2 and 5.3 make same power at same afr.

What this analysis is missing is that the power equation (P = n x Q x fuel flow rate ) is true for the same engine 5.3 vs 5.3 or 6.2 vs 6.2.
But comparing 6.2 vs 5.3 the main difference is the displacement. The flow rate equation for fuel even shows a direct proportionality to displacement. The 6.2 will draw more air and require more fuel for a given afr.

Here is why.

Fuel flow rate is dependent on afr. There is only a specific range of afr where a combustible mix can occur.

Take 14.7.

We will assume air density, in cylinder, is same between 5.3 and 6.2.

It may be different at extremes of engine operation, but not enough to alter the outcome of the discussion.

For ease of illustration let's say the air density in cylinder is 1 kg/L.

A 5.3 will have 5.3L x 1kg/L = 5.3 kg of air. To get 14.7 afr, then the fuel will have to be 5.3kg/14.7 = 0.36 kg fuel. 5.3 kg air/ 0.36 kg fuel = 14.7.

A 6.2, following same method, will have 0.42kg of fuel.

Since this is over the same time scale this is also the flow rate of fuel.

You can see then that the 5.3 will have less fuel than 6.2 at same afr.

So...with less fuel in this equation P = n x Q x fuel flow rate, it will not have the same power, P, as a 6.2 at the same afr.