Belgium takes a next step against GW

[Pressure Drop]

Let's do some physics here, because I couldn't find a suitable graph anywhere

approximate air resistance F=½Capv^2

where C is acoefficient of friction, a factor depending on the shape of a car and determined by experiment
a is the frontal area of the car
p should actaully be the Greek letter rho. Represents the density of air
v is the speed of the car

As you can see, it's a squared function, which means increases in speed result in very big increases in air resistance, when the factor grows enough

So why isn't it most economical to drive at walking speeds? Air resistance is then an irrelevant coefficient, but other factors (that we don't care about now) become dominant.

Apparently, speeds of 50-70 km/h are most gas efficient with most cars, after that the needed fuel per 100 kilometres increases drastically.

nice question jeansi

i've heard the speed you've quoted before. i've always assumed and never question it any further cuase i don't drive myself. --- that with something like the equations you give over the fact that the energy required to run the engine balance out at this. i.e. the pistons are fired by the engine burning fuel this will lead to a peak efficiency. Thought that the engines were designed that their peak effecincy would cover the average driving speed.

i'm not a mechanical engineer i don't know making it up thats what i'd assumed

[Displaced]

depends on the car, but when speed increases, air resistance does play a huge factor.. but under around 100km/h air resistance isnt a major player.

e.g. my car will do around 9l per 100kmh going 60, it will do the same going 100kmh

above 100, it starts to increase like a motherfucker, at 120 its doing about 12l per 100km, 140 is around 14l per 100km 180 is around 20l per 100km and 200 it was around 30l per 100km.

i remember doing something in physics that was related to this, i.e. we found out the amount of power needed to accelerate a car with a mass of a 1000kg to 100kmh, it wasnt a very large number, something like 40kw, but trying to get it to 200 required around 120kw, purely due to air resistance.

[Da1andonly]

Just remember folks, try to drive at 1500rpm.

Displ, call me when U wake up!

[Barton]

Do you guys have emissions testing? We have it here in Ontario, where your car has to be checked every few years to make sure that it's not spewing that much bad stuff out the back end.

Yes, very year (in belgium)

[Pandagirl!]

I'm with Jerome. I get the best gas mileage when I'm driving 70-80 as opposed to 50-60.

[HeavenSent]

I'd like to see 'them' pull that shit in L.A. California... or anywhere on the west coast for that matter... cept maybe San Francisco... the PC Liberals run that city.. Still, there'd be anarchy on the west coast... Then again, maybe it wouldn't make a difference because everyone speeds 10-20 mph faster than the limit as it is.

Is that a Texaco gas station in that picture? How many American oil companies are there abroad? How common are they?

I've always thought the optimal efficient speed to drive was 45 mph. ^-^


Edit:>Letterman takes the i from Texico and replaces it with an a for Texaco. And people from every walk of life, rich and poor, put their differences aside, come together to praise the glorious one that had entered to correct the typo, and from all around the world, the roar of their resonant love could be heard, followed by their bubbly bongs singing their bubbly songs. :wub:

BP is really popular here too

[Emaho]

It also depends if you have the right pressure in the tires or not.
You should always aim to have as low rpm as possible, on all gears. That's why they new diesel cars are really good compared to the cars driven with petrol.

HS I think it's called Texaco over here. Shell is pretty common too.

[Galleleo]

Shell and BP are the biggest gas stations in Europe I think. Shell is Dutch and BP is British (British Petrol)

[Doc Flabby]

interestingly smog actually cools the earth. Cleaner emissions are accelerating global warming. Therefore the logic of this proposal is flawed.

[Emaho]

Shell and BP are the biggest gas stations in Europe I think. Shell is Dutch and BP is British (British Petrol)

Oh I always thought Shell was American! BP used to stand for British Petroleum but since they are into more the Petrol these days they changed their name to just BP while saying it stands for Beyond Petroleum.

[Vihta]

depends on the car, but when speed increases, air resistance does play a huge factor.. but under around 100km/h air resistance isnt a major player.

e.g. my car will do around 9l per 100kmh going 60, it will do the same going 100kmh

above 100, it starts to increase like a motherfucker, at 120 its doing about 12l per 100km, 140 is around 14l per 100km 180 is around 20l per 100km and 200 it was around 30l per 100km.

i remember doing something in physics that was related to this, i.e. we found out the amount of power needed to accelerate a car with a mass of a 1000kg to 100kmh, it wasnt a very large number, something like 40kw, but trying to get it to 200 required around 120kw, purely due to air resistance.

Bugatti Veyron needs just 270 horsepower to do 155 mph, but the 100mph (up to 253 mph) after that needs extra 730 horsepower (1000hp total)

[Displaced]

yeah, so thats pretty accurate..

considering the veyron is what? 1800kg

and air resistance increases exponentially.

[ZeUs!!]

interestingly smog actually cools the earth. Cleaner emissions are accelerating global warming. Therefore the logic of this proposal is flawed.

Yeah lets have some more smog

BP = British Petroleum and Shell is Anglo-Dutch, I go past the Shell Centre on the way to work every day
The Royal Dutch/Shell Group of companies was created in February 1907 when the Royal Dutch Petroleum Company (legal name in Dutch, N.V. Koninklijke Nederlandsche Petroleum Maatschappij) and the "Shell" Transport and Trading Company Ltd of the United Kingdom merged their operations - a move largely driven by the need to compete globally with the then monopolistic American oil company, Standard Oil. The terms of the merger gave 60% of the new Group to the Dutch arm and 40% to the British.

[Galleleo]

So, the majority is still Dutch.

[Emaho]

Yeah lets have some more smog

BP = British Petroleum

Wrong