I've recently been looking at the mpg that I am getting from the Mondeo. I've only been judging on what the trip computer tells me, rather than keeping track manually.
Anyway, as part of this, I have the trip computer display set to show the current mpg. I am maybe imagining it, but I certainly seem to get a better mpg when the engine has been running for a few minutes.
Is that possible?
It's hard to do a like for like comparison, because the bits of road that I normally travel when the engine has just been started, or different to those I travel when it has been running a while.
|
|
I think you have discovered what used to be called a "choke" but is now done by the computer gubbins.
|
|
As ON has observed, the fuel enrichment provided by the computer and fuel injection is way more efficient than a manual choke and carbs plus, as the engine gets warmer so does the oil and, even with a multigrade, there will be lowering the internal friction of the rotating parts = better mpg.
|
>>I am maybe imagining it, but I certainly seem to get a better
>> mpg when the engine has been running for a few minutes.
>>
>> Is that possible?
>>
Most certainly, an engine will use more fuel when cold and will only reach optimum efficiency when fully up to temperature.
|
Remember choke knobs?
It's necessary to enrich the mixture when the engine's cold, so yes, it will use more fuel. This is done on modern engines by the engine management control. We can't be trusted to adjust the mixture manually on cars fitted with catalytic converters.
|
>> Remember choke knobs?
Only very vaguely :)
Thanks for the responses guys. I suppose my next questions would be how long does it take to get up to an efficient temperature and how inefficient should I expect it to be before it gets to that temperature?
|
The length of the piece of string is dependent on the ambient temperature, the cars thermostat characteristics, engine load, (mechanical and electrical), heater use, aircon use, whether the car has an oil cooler, gearbox temperature, tyre temperature and pressure, and loads more I expect.
Tell us this lot and we will try to come up with an answer, not necessarily a sensible one though. :-)
Last edited by: Old Navy on Mon 14 Feb 11 at 10:16
|
>> The length of the piece of string is dependent on the ambient temperature, the cars
>> thermostat characteristics, engine load, (mechanical and electrical), heater use, aircon use, whether the car has
>> an oil cooler, gearbox temperature, tyre temperature and pressure, and loads more I expect.
>>
>> Tell us this lot and we will try to come up with an answer, not
>> nessisarily a sensible one though. :-)
OK, OK, I get it :-)
I'm really just wondering if, when I start it up on a cool morning (say 10C), I should expect to see a very noticeable reduction in mpg, and roughly how long it would take to get up to temperature.
I might, for example, start it up, and only drive a couple of miles (at 30 mph). Would that likely get it up to temperature? What ballpark figure for mpg might I expect if, say, I get 40 mpg when it is up to temperature? Does it burn through fuel very quickly at the start but then rapidly get more efficient? Or is it just a bit less efficient when it is cold? Again just looking for ballpark stuff.
Last edited by: SteelSpark on Mon 14 Feb 11 at 10:22
|
|
As a rough estimate add the Urban, Extra Urban, and Combined consumption figures for the car, divide by four, and when you are at about that figure of fuel consumption it has warmed up.
|
|
Only when there is an R in the month.
|
>> Only when there is an R in the month.
Don't suppose I'll be getting much help from Zero for a while :(
|
...Don't suppose I'll be getting much help from Zero for a while :(...
Dunno about that, but your attempt to over-intellectualise the footie ground thread was wearisome.
Most of us left that debating skills garbage behind when our voices broke.
You only kept Zero and Alanovic on the hook for so long because of their passion for the game.
I'm not so bothered, which is why your attempt to get me to participate in a similar style of argument in the Rooney goal thread failed.
|
>> Dunno about that, but your attempt to over-intellectualise the footie ground thread was wearisome.
>>
>> Most of us left that debating skills garbage behind when our voices broke.
Oh, excuse me for trying to have a bit of an intelligent debate on a forum, rather than just making a claim and then telling the other person that they are not qualified to comment.
It's probably a good job you gave up on debating when your voice broke, if your justification of your waffle about "low skill" Premier League players is anything to go by.
I'm sorry I made your argument look stupid.
|
...I'm sorry I made your argument look stupid...
Tripe, you wanted to make my point look stupid and had you succeeded you would have been pleased, not sorry.
The game's about opinions.
If you think Premier League players, in general, are skilful, that's fine.
I think many lack basic skills, trapping the ball cleanly being the most obvious.
Being able to kick with either foot being another.
|
>> Tripe, you wanted to make my point look stupid and had you succeeded you would
>> have been pleased, not sorry.
I did succeed, not because I particularly wanted to, and I'm sorry because it has clearly annoyed you, which wasn't my intention.
>> I think many lack basic skills, trapping the ball cleanly being the most obvious.
It is clearly misguided to think that Premier League sides, with a huge pool of professional players to pick from, would somehow pick those with low skill.
If alternatively, you think that there simply aren't enough players available that match your "basic skills" criteria, it is equally misguided to think that your "basic skills" criteria is realistic.
I doubt you can't see this, but you just don't want admit that you made a silly comment, that can't possibly be justified.
|
>>I doubt you can't see this, but you just don't want admit that you made a silly comment, that can't possibly be justified.>>
Give it a break SS, we didn't say you were asking silly fuel consumption questions, regardless of what we thought.
And I don't have the remotest interest in overpaid posers kicking a ball around a field.
Last edited by: Old Navy on Mon 14 Feb 11 at 15:31
|
>> Give it a break SS
Be fair ON, have a look at Iffy's post of 11:15am, and then tell me who should be giving it a break.
If he wants to butt in and start being rude, he can be the one to give it a break.
>> we didn't say you were asking silly fuel consumption questions, regardless of what we thought.
God forbid that I ask a motoring related question on this forum, and what exactly is so silly about asking whether you get greater fuel consumption at low temperatures?
Last edited by: VxFan on Mon 14 Feb 11 at 20:46
|
>> >> Only when there is an R in the month.
>>
>> Don't suppose I'll be getting much help from Zero for a while :(
Of course you will, it was only gentle ribbing on the soccer thread. You are tho asking a really "how long is my string" question. Far too many variables unique to you to answer in the kind of detail you require.
In brief, it uses a lot more at startup, even more when its colder. This goes down the further and longer you travel till your temp gauge is at normal.
So lots of short (1-2 miles) trips in the cold, means more fuel.
|
>> Of course you will, it was only gentle ribbing on the soccer thread.
Thanks Zero. For what it's worth, you're right that I don't have a strong allegiance anymore. Used to when I was younger, but it has faded significantly over the years. Its decline has been matched by increased intransigence though :)
>> In brief, it uses a lot more at startup, even more when its colder. This
>> goes down the further and longer you travel till your temp gauge is at normal.
>>
>> So lots of short (1-2 miles) trips in the cold, means more fuel.
Yeah, that is pretty much what I am seeing. Had a much longer run this morning, and the economy was much better on the same bit of road later on.
|
>> As a rough estimate add the Urban, Extra Urban, and Combined consumption figures for the
>> car, divide by four, and when you are at about that figure of fuel consumption
>> it has warmed up.
>>
EDIT:- I use this system to get a ballpark fuel consumption figure for any car I am thinking of buying. I find it more accurate than the raw manufacturers figures, but then anything would be. :-)
|
|
Combined -10% is also a fair approximation in my experience.
|
>> Combined -10% is also a fair approximation in my experience.
Agreed, I use Parkers combined and subtract 3mpg, this works on my daily commute.
|
As a rough estimate add the Urban, Extra Urban, and Combined consumption figures for the
>> car, divide by four, and when you are at about that figure of fuel consumption
>> it has warmed up.
Yaris D4d: as above calculation 48.0mpg
Real life mainly town: 57mpg.
Utter fail.
|
It all depends what sort of driving conditions we encounter on our average drives.
I tend to get about 10% above the urban figures.
|
Yeah, I used to get around combined figure + 10% when I was going up and down busy motorways. Now I work from home and do few longer journeys, my economy is more like half way between urban and combined.
I do touch the extra urban figures sometimes, but only when I do long trips between England and Scotland, and I stay disciplined with the throttle. Boring as hell mind.
OTOH, if I do nothing but short trips in cold weather, even the urban figures can be optimistic.
|
>> Yaris D4d: as above calculation 48.0mpg
>>
>> Real life mainly town: 57mpg.
>>
>> Utter fail.
>>
I don't drive like a granny, I am a geriatric hooligan. :-)
|
>> I don't drive like a granny, I am a geriatric hooligan. :-)
>>
We all knew that already...:-)
|
Warm engine and fuel economy - Old Navy
