Fuel Consumption

static

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Jan 12, 2005
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Southern Finland
How do car companies measure their fuel consumption?

For example Honda Civic Type-R does 32 mpg:s combined.
Is that with A/C on? Is it the most economic outcome you can get or just an average consumption wich is fairly easy to achieve?
 
Hi!

Well, normally the manufacturers give you several numbers. For instance average fuel consumption (city and cross-country driving), and maximum/minimum. Most of the time they're very optimistic with their averages though! ;)

In case of the Civic Type-R, that can't be the average! Maybe the minimum fuel consumption when you're havong no fun at all. :p
32 mpg is 7.3 l/100km! Yeah, it's only a 2l 4 cylinder engine but let's not forget it has 200hp!

cya
Oliver
 
32 mpg will probably be with short shifting, driving grandmother style and everything electrical option turned off.

My 1.1l fiesta does 32mpg combined, so a much heavier / more powerful car can't manage that eventhough it's a more modern engine.

edit: the Belgian civic type R uses about 8.9 l/100km according to the brochure. I don't know how much that is in mpg but it must be less than 32 since 32 equals 7.3 liter. The Belgian test driver drives less grandmother-ish. :)
 
1 gallon (US)=3.78541 liters
1 gallon (UK)=4.54609 liters

Data taken from my SX1's converter, should be accurate. :)

cya
Oliver
 
Well, since a US gallon is around 3.8 and a UK one is 4.5, I guess it's different... ;)

US gallon x 1.2 = UK gallon
 
jensked said:
A week or two ago, I posted an URL where you can calculate mpg (UK and US) to l/km and others. But I can't find it anymore :).

Don't know which post it was and I can't find it on google anymore. But I think the URL has .ac.xx or .edu in it.

Yeah, I remember it, but don't know where, too.
 
Re: Fuel Consumption

static said:
How do car companies measure their fuel consumption?

For example Honda Civic Type-R does 32 mpg:s combined.
Is that with A/C on? Is it the most economic outcome you can get or just an average consumption wich is fairly easy to achieve?

Mitsubishi run their cars on a road dyno that has a preset course programed into it.

They get a guy in it and he watches a screen and tries to keep the car running inside certain parameters.
 
I am not too familiar with that mpg-stantard either.
My Honda dealer told me TypeR does a bit over 9l / 100km with normal driving using A/C and not being too carefull.

Thanks for the info :thumbsup:
 
I think the answer to this in driving school was, they put the car on to a test bench and then "drive" a certain kind of program through. For example, when testing city consumption, there will be lots of acceleration with small gears and when testing highway consumption, it will be pretty much just cruising at certain speeds and certain gears. Of course they always try to get as small numbers as possible, so everything electrical is turned off, rolling resistance is minimal and they don't even consider air resistance to have anything to do with fuel consumption.
 
Yeah, cars are bench-tested. They also measure the pollutant levels in the same way, but I don't know if they do it on the same runs as the fuel consumption tests.
Without bench tests it'd be impossible to have repeatable results, as air temperature and humidity, traffic flow, changes in tire wear etc. would all affect a test ran in the real world.
Thus, the results usually seem to be removed from the real world. I'd use them just to estimate the differences between different engines in the same car model or between the models of a given brand, but not between different brands.

I've rarely gotten close to the factory figures, mostly due to my aggressive driving style. Factory figures for my current car are around 6,5 l/100 km extra urban, 11 urban and 8,5 combined.
I drive around 50/50 urban/extra urban, with an average fuel consumption of 11 l/100 km.

My smallest consumption was in a 900 km run with the tankful used between 200-700 km averaging 7,3 l/100 km. And that was a cool autumn night, with no traffic, near optimal air temp for the engine and cruising speed between 100 and 150 km/h.
 
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