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Your thoughts please
- Thread starter JackRussell
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And that is exactly what I said....
All to do with torque - as i said in post 29.
Didn't think it need much more explanation than that.
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And what Wammers was saying that if you take load out of the equation, then by simple physics, a larger capacity engine will use more fuel to maintain the Stoich Mixture Ratio....
Which is what I said in post #24 that the variables at work in the real world due to load and etc would be very difficult to calculate.....
And just to put my experience into the mix as you did in post #44, my Post Graduate Degree was in Aeronautical and Aerospace Design Engineering focusing on Thermodynamics and Thermofluids applied to Gas Turbine Design...although I may not have your 20 year experience (as I am only 36)
Datatek
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The amount of air inducted is governed by the throttle opening, not the cylinder size. Mixture ratio for a given amount of air is govened by the ECU.
A long stroke engine of a given capacity will produce more torque for a fixed amount of fuel than the same capacity short stroke engine.
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And what Wammers was saying that if you take load out of the equation, then by simple physics, a larger capacity engine will use more fuel to maintain the Stoich Mixture Ratio....
Which is what I said in post #24 that the variables at work in the real world due to load and etc would be very difficult to calculate.....
And just to put my experience into the mix as you did in post #44, my Post Graduate Degree was in Aeronautical and Aerospace Design Engineering focusing on Thermodynamics and Thermofluids applied to Gas Turbine Design...although I may not have your 20 year experience (as I am only 36)
Well i am educated to a certain degree. With 53 years of practical experience, i have been a keen amateur gynecologist for longer than that, so if any of the ladies needs an examination i would be willing to help out. Please note i have my own mobile damp sponge to dip in Dettol.
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At a given engine speed with no load which was quoted, the air ingested is constant. The larger the cylinder the more air will be ingested and therefore will need more fuel to maintain mixture ratio. The mixture ratio is not governed by the ECU it is maintained at around 14/15 to 1 by it, subject to throttle opening, less air less fuel, more air, more fuel to maintain the mixture ratio. Diesel engines are somewhat different.
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Oh very much so...in the real world, MPG comparisons are very tricky which is why the standard tests for Urban, Extra Urban and Combined where devised...to try an give some form of comparison which takes into account the variables at play as theoretical calculation would be a minefield...so you are both right in both your arguments, and as I put in post #59 the real world values differ by 3-5% whereas the theoretical is 13%...the 4.6 makes up the deficit by virtue of more torque which is a measure of how efficiently a machine generates work or power....so the 4.6 can close the gap due to it being a more 'work efficient' engine!
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The fuel consumption figures for the 4.0 litre and 4.6 litre Land rover V8s with torque effects taken into consideration (road tested using the same procedure) would seem to indicate that the 4.6 uses more fuel than the 4.0 litre. Now how much longer are you going to prattle on about something you obviously don't understand?
Datatek
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As I said, the amount of air ingested on a petrol engine is governed by the throttle opening, the ECU adjusts the amount of fuel injected proportionate to throttle opening, obviously maintaining a stoichiametric ratio.
I never said the 4.6 gave better MPG than the 4.0. What i said was the difference is marginal.
What you said was that a bigger engine capacity will always result in less MPG which is incorrect.
Anyway, cant argue with a brick wall so will leave it at that.
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I never said the 4.6 gave better MPG than the 4.0. What i said was the difference is marginal.
What you said was that a bigger engine capacity will always result in less MPG which is incorrect.
Anyway, cant argue with a brick wall so will leave it at that.
So a Bugatti Veron uses less fuel than a Ford Fiesta then. A five litre engine uses less fuel than a one litre engine because it has more torque. Don't talk through your arse. You live in a dream world of fairies and furry animals. Your not talking to one of your piston head buddies down at the bloody pub here. When you have a clue what you are on about come back think it maybe a long time.
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Oh dear,
Where's the 1ltr / 5ltr engine comparison come into this????
So your disputing figures that show a 4.4TDV8 to have better fuel economy than a 2.5TD?
Right, over & out.
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Don't talk through your arse it is a totally different engine design. Progress has been made between the two engines. That is what you don't understand. Don't try to teach your granny to suck eggs. What do you design with your fancy qualifications? Toilet seats.
& a Bugatti Veyron uses the same but larger capacity engine as a Ford Fiesta does it?
I totally understand the differences at play between engines, thats the whole point. You made the statement that larger engines equals less MPG.
I'm not the one with a case of verbal diarrhoea.
If you want to insult & disparage others who disagree with you then go ahead.
I totally understand the differences at play between engines, thats the whole point. You made the statement that larger engines equals less MPG.
I'm not the one with a case of verbal diarrhoea.
If you want to insult & disparage others who disagree with you then go ahead.
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Difference here is i know what i'm talking about and you don't. You obviously still do not understand the required mixture ratio needed in petrol engines for clean efficient burn. A larger cylinder has more air in it at any given time and therefore needs more fuel than a smaller cylinder would under the same conditions, simple as that. Is that so hard to follow? We know the difference in the 4.0 and 4.6 engine is only 600 cc that is why the difference in fuel used is comparatively small as well explained by Ant. By your reasoning if they increase the 4.6 to 5.0 litres and give it more torque maybe it could beat the consumption figures of the 4.0 litre engine. It simply does not work that way. In general terms the larger the engine the more fuel it needs.
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Wammers, do you often argue with your own shadow?
No just people who think they know something they don't.
2.0_hippo
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:boxing:
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