US & European Fuel economy rating

[robertp]

For the 2010 Prius

European:
Combined city / highway: 3.9 ltr/100 km = 25.6 km/ltr = 60.3 mpg

US:
Combined city / highway: 50.0 mpg = 21.3 km/ltr = 4.7 ltr/100 km


In Europe they are using fuels with 95 octane (they do not have less than that). Here in the US 87 octane fuels. Would that be the reason for the 10 mpg difference?

[Tideland Prius]

Originally Posted by robertp

For the 2010 Prius

European:
Combined city / highway: 3.9 ltr/100 km = 25.6 km/ltr = 60.3 mpg

US:
Combined city / highway: 50.0 mpg = 21.3 km/ltr = 4.7 ltr/100 km


In Europe they are using fuels with 95 octane (they do not have less than that). Here in the US 87 octane fuels. Would that be the reason for the 10 mpg difference?

Umm... no because you're not comparing the same Octane. Actually, I think 95 might be our 91 for that matter. If it isn't, then that's our 87. They're using a different calculated number than we are (It's always amusing to see people exclaim how other countries get 100 Octane).

Testing methods are different too. In Canada, our combined city/highway number is 3.8L/100km which is close to the European number.

[JimboPalmer]

Not your numbers, but another problem with 'European numbers' is that they may use an imperial gallon, 5/4 of a US Gallon. There was a 88.5 MPG micro-car diesel blurb the other day that used imperial gallons and the European test. Very impressive, until you realize that a Prius using the European Test and imperial gallons gets 73.3 MPG in a midsized car.

[Tideland Prius]

Originally Posted by JimboPalmer

Not your numbers, but another problem with 'European numbers' is that they may use an imperial gallon, 5/4 of a US Gallon. There was a 88.5 MPG micro-car diesel blurb the other day that used imperial gallons and the European test. Very impressive, until you realize that a Prius using the European Test and imperial gallons gets 73.3 MPG in a midsized car.

He converted it correctly. 3.9L/100km = 60mpg US.

[spinkao]

Originally Posted by Tideland Prius

Umm... no because you're not comparing the same Octane. Actually, I think 95 might be our 91 for that matter. If it isn't, then that's our 87. They're using a different calculated number than we are (It's always amusing to see people exclaim how other countries get 100 Octane).

Testing methods are different too. In Canada, our combined city/highway number is 3.8L/100km which is close to the European number.

You are correct. Our 95 octane Basic corresponds to the 91 octane U.S. Premium. Details can be found here:

Octane rating - Wikipedia, the free encyclopedia

Octane_rating

There are also other threads on this topic around.

[spinkao]

Originally Posted by robertp

For the 2010 Prius

European:
Combined city / highway: 3.9 ltr/100 km = 25.6 km/ltr = 60.3 mpg

US:
Combined city / highway: 50.0 mpg = 21.3 km/ltr = 4.7 ltr/100 km


In Europe they are using fuels with 95 octane (they do not have less than that). Here in the US 87 octane fuels. Would that be the reason for the 10 mpg difference?

No, it is not because of the higher octane fuel. On the contrary, you usually get *worse* mileage when using higher octane fuel, as it has lower energy density (you can find other threads on this here). It is because of different testing cycle (I would say ).

[Mike Dimmick]

Entirely because of the different testing cycle and parameters. Our numbers come straight off the dyno while the US EPA discounts their numbers a bit; in addition, the US test cycles were always stricter anyway, and now include sustained high speed/high acceleration driving, use of air conditioning, and cold temperature running.

You can find out more about the EU tests at VCAcarfueldata.org.uk - Fuel Consumption Testing Scheme, and about the EPA tests at Fuel Economy Test Schedules.

The numbers for the Prius on the UK test, from Gen 2 to Gen 3, improved 10% in the 'extra-urban' part of the cycle and 28% in the 'urban' part. I believe this is down to the exhaust heat capture system on the new car - we didn't get the coolant thermos on Gen 2.

[RoyalBlue]

Earlier European test cycles had figures for city traffic, country road traffic (80 km/h) and highway traffic (120 km/h). The present highway figures are not very realistic in my view, an average speed of 63 km/h on the highway is not highway speed in my view. When I drive home form our head office, I will drive at appr. 130 km/h for 2 hours, and then you will have a very different fuel consumption. In fact many modern European petrol or diesel cars of the same size will have a better fuel consumption than the Prius in these conditions. The Prius really excells in city traffic, there the hybrid drive has a real advantage, not in constant speed situations on country roads or highways.

[JimboPalmer]

Originally Posted by Tideland Prius

He converted it correctly. 3.9L/100km = 60mpg US.

I did start my post with "Not your numbers" as he had them correct, I was merely pointing out additional dangers comparing the two sets of mileage.

[Airbalancer]

Which country do they use km/l rating?
last night on a 80 km trip with the cruise set at 104 km/hr the OBC read out was 3.9 l /100km

Is there many threads on the forum about how much better metric is for units measurements