Speeding “Class of vehicle” (Kombi 2040kg)

[oldiebut goodie]

Not strictly true, a mass travelling at constant speed (ignoring friction ie air resistance) needs zero force to maintain that speed. The reason that it uses more fuel at 70 than 50 is that the drag force (air resistance) that the engine has to work agains is significantly higher (approx double) so using more fuel.

The mass of the vehicle will however have a big influence on the amount of fuel used when accelerating (provided all other factors ie shape of vehicle are constant).

I appreciate this is a simplified explanation and there are lots of other less significant factors to take into account.

Not the point of my post!

 

[Lubrown]

"Your MPG has shot up from you driving slower? If that’s the case something is very wrong. Typically driving at 70mph uses 9% more fuel than driving at 60mph and 15% more than driving at 50mph. That’s basic science- you need more fuel to propel a mass faster.

Are you holding it in a lower gear?"

Are you mis-reading the above? You have just explained why the mpg has increased yet say that there is something wrong? Are you confusing increase and decrease?

Yes, I completely mis-read it. Thanks for spotting that and setting me straight.

Making a mental note to re-read posts before commenting.

 

[oldiebut goodie]

Shot up = increased = doing more miles per gallon.

That's how I read it anyway.

Correct - mpg not gpm!