Fuel fill up to max?
- Thread starter mustang1
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steve292
Veteran
- Location
- Weston-super-mare, north somerset
Open a window, and all the arguments over weight become massively irrelevant. Why do you think millions is spent on drag reduction and naff all on reducing fuel tank sizes as MPG increases?
classic33
Leg End Member
Weight remains constant, volume will change
classic33
Leg End Member
The Citreon CV2?All that torque for a split second, then it's gone. All that noise. All that smell. All that filth from the tailpipe.
James Bond never drove a diesel. Thomas Magnum's Ferrari wasn't a diesel. Donald Trump doesn't get chauffeur driven round in a Massey Fergusson
Trump would use a Ford, American. Ferguson being the only person to tell Ford what to do.
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mustang1
Guru
- Location
- London, UK
[QUOTE 5328692, member: 9609"]1200kg could be the weight of a small car and driver? if you add 30kg of fuel to that car then its weight goes up by 2.5%. I guessed at 40% of the energy used was to overcome rolling resistance, so therefore if the vehicle is 2.5% heavier then fuel consumption could go up by 1%
the 40% bit is certainly debatable - It used to be said that a lorry travelling between 50 and 60 mph that 40% of the fuel went towards overcoming rolling resistance, 40% went to overcome wind resistance and the other 20% was other wastage. (abve about 55mph wind resistance takes over as the biggest user of enegy). I guess a typical car will have far lower wind resistance so may be the 1% figure is a little low?[/QUOTE]
If we take a car which weighs 1000kg and you have to push the car from standstill, you will use X Watts of power. If the car weighs 2000kg, you do not need 2X Watts of power; you may need something like 1.5X Watts (ie less than double power required to push car, dont forget, it's on wheels, not a block which has entire surface area in contact with ground).
When the car is moving at 20mph, the 1000kg car needs 1.3X Watts to accelerate, and the 2000kg car needs 1.4X, if both cars are to accelerate at same rate. The point is, you need less power than when the is pushed from standstill. And you need lower multiple of power to move the both the 1000kg car and the 2000kg car once they are both moving (at higher speeds, wind resistance takes a high precedence and the power required to move each car is higher for same acceleration, but I'm giving example for lower speeds).
So in summary, to move the 2000kg car requires more fuel than to move the 1000kg car, but it's not twice as much fuel.
the 40% bit is certainly debatable - It used to be said that a lorry travelling between 50 and 60 mph that 40% of the fuel went towards overcoming rolling resistance, 40% went to overcome wind resistance and the other 20% was other wastage. (abve about 55mph wind resistance takes over as the biggest user of enegy). I guess a typical car will have far lower wind resistance so may be the 1% figure is a little low?[/QUOTE]
If we take a car which weighs 1000kg and you have to push the car from standstill, you will use X Watts of power. If the car weighs 2000kg, you do not need 2X Watts of power; you may need something like 1.5X Watts (ie less than double power required to push car, dont forget, it's on wheels, not a block which has entire surface area in contact with ground).
When the car is moving at 20mph, the 1000kg car needs 1.3X Watts to accelerate, and the 2000kg car needs 1.4X, if both cars are to accelerate at same rate. The point is, you need less power than when the is pushed from standstill. And you need lower multiple of power to move the both the 1000kg car and the 2000kg car once they are both moving (at higher speeds, wind resistance takes a high precedence and the power required to move each car is higher for same acceleration, but I'm giving example for lower speeds).
So in summary, to move the 2000kg car requires more fuel than to move the 1000kg car, but it's not twice as much fuel.
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mustang1
Guru
- Location
- London, UK
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mustang1
Guru
- Location
- London, UK
I drove 3000 miles across 4 states in 2.5 weeks in a mustang convertible. With gas prices so much cheaper than UK, I was rockin' every inch of the way.
Drago
Legendary Member
- Location
- Suburban Poshshire
When I was in the states, the land of the V8 gas guzzler, I thought to myself "well, when in Rome", and drove a VW Rabbit like the natives did.
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mustang1
Guru
- Location
- London, UK
Its weird how the word mileage comes from mile, but there is no such thing as kilometreage from kilometre.For such a simple question this thread has some serious mileage in it.
Keeb students of fuel comparison will notice that the dastardly Forrin practice of using litres per km to measure fuel use can be resolved into units of area. For more fun one can therefore state fuel consumption in acres. #takingbackcontrol
marzjennings
Guru
- Location
- Houston, Texas, USA
- Location
- The TerrorVortex
Miles per gallon can also be resolved into units of area.
Even better is the Specific Impulse, used as a measure of rocket motor efficiency.
It's essentially fuel used per second, divided by thrust produced, and is expressed in seconds!
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Miles per gallon resolves into inverse area as it's length divided by volume rather than volume divided by length.
- Location
- The TerrorVortex
Yes, you're right. I misremembered something I read on xkcd a while back...
