It's probably all just talk to give the impression, as always, that something is being done.
Another name for it is spin.
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I'm guessing the original posting was refering to aviation fuel.
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I hate to admit it but my computer indicates that my vehicle (2.5 V6 petrol) uses alot less fuel at 60MPH on a mway against 75MPH. - The computer seems fairly accurate on the average figures and the above is setting it on instant consumption. The difference is surprising.
The next time I do the Uni run I may solenmly promise not to exceed 60MPH for the whole trip and check overall consumption and time taken.
This could be an eye opener but I will need to take plenty of discipline pills with me!!
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Someone who knows will no doubt be along soon to correct me, but isn't it the case that the UK puts out something like 2% of the worlds CO2, and that of that 2%, a good deal less that 50% is put out by cars?
If that is right, then taking into account that fact that the large majority of miles are travelled at under 70mph, I wonder how much of a co2 problem is caused by people breaking the speed limit on motorways?
If there is going to be strict enforcement of motorway speed limits, then they whould be raised to at least 80mph.
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Makes a huge difference (brim/brim) in our Berlingo as well. Less noticeable in the Xantia Estate, mainly aerodynamic drag I suspect.
RAC foundation raise the question of whether it is just to issue penaly points when the limit is enforced for economy rather than safety.
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Nsar,
Yes, I did mean aviation fuel. After all, this is not too dissimilar to diesel.
I quite fail to see how the measure will be implemented to an effect greater than it currently is without increasing resources considerably. ie., more traffic police, more safety cameras, GPS black-box monitoring of speed.
As usual, of all of the users of hydrocarbons, it is the group of people with the least resources in terms of lobbying and representations to government that will foot the bill.
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All I know is that if they decide to do this, it will alienate the public and make my job even harder!
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>>Yes, I did mean aviation fuel.>>
Top Gear magazine ran an article on pollution caused by various forms of transport about two years ago.
One of its most interesting facts was that a 747 flight from London to Sydney caused more pollution than two years of F1 testing and racing....:-)
I've still got it somewhere - that is if the other half, as seems ot be her mission in life, hasn't discreeting disposed of it and various other magazines.
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My Missus too..............What 'other' magazines!
VBR........M
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>>What 'other' magazines!>>
Shame on you...:-) Computer titles stretching back years....
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What\'s for you won\'t pass you by
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In vehicle design studies, it is usually assumed that aerodynamic force is proportional to velocity squared. At high speed, aerodynamic force is the dominant contribution to the road load equation.
So, in terms of power, this means that the aerodynamic power requirement scales as velocity cubed. This power scaling read across reasonably well into a fuel flow.
Also, rolling resistance rises with speed.
So, going fast just wastes fuel and produces needless emissions.
Having said all that, it as nothing when compared with the fuel burn and emissions from aircraft. Without checking up, I'm not sure if this is true, but I have heard that the power required by something like a 747 at take off would provide sufficient electricity for a city like Norwich!
Number_Cruncher
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Gearing is really the issue - if your car revs less, it uses less fuel.
Make more sense to insist all new cars have minimum 6 speed boxes ...
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Gearing is really the issue - if your car revs less, it uses less fuel.
It is not quite as simple as that, the car has got to produce enough power to move at that speed whatever revs/gearing.
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Now I know nothing, but surely final drive ratio for those motorway journeys must be critical.
VBR.........M.
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Makes a huge difference (brim/brim) in our Berlingo as well. Less noticeable in the Xantia Estate, mainly aerodynamic drag I suspect.
How about Tax breaks for people who still buy cars with a low drag coefficient !
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/controversial with points exaggerated for effect without reducing their validity mode equals on
I can't understand it. Why don't we just get rid of vehicles completely? After all, that way we could stop the 1.5% of CO2 emissions that come from all transport, and then we could try to do something about those darned volcanoes that produce the other 98.5%. That and breathing.
Mind you, as I see the latest wheeze is that co2 is NOT the main problem after all - it's water vapour instead - we don't need to worry.
It's not often I side with the Americans but honestly. Global warming due to man? Yeah right.
/end controversial
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And where, in this cluttered land of ours, can we do more than 70mph?
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Its very difficult to know about global warming, and whether or not it is actually caused by man. Whether the world is getting hotter or colder, whether it is actually getting temporarily hotter in an overall period of getting colder.
I'm sure I don't know the truth of it. However, whatever is the truth I am convinced that cars in the UK are not a significant contributor, and that the [small] proportion of car journies which are done over 70mph are no way a major or significant contributor - especially since its not that simple - a car running faster will run less economically but will actually be running for less time - who knows which is worse, but its marginal.
However, I am fairly sure that times were different in the past. Different in that your working life was spent closer to home, and when travel was neccessary it was done more slowly. I suspect that I would have enjoyed those times more. Its not that I don't want to drive, or that on occasions I wdon't want to drive fast, its that I don't like having to drive a long way to work nor do I like the fact that its done at high speed - acknowledging that both of those things are my fault and responsibility.
And the mroe the roads slow down the more viable the trains become. The more [decent] people that use the trains then the cleaner, more pleasant they will become. Conceivably the more services will be available as the equation of viability is shifted.
The net result is that I really don't have a major issue with them slowing down the roads. I don't like them lying to me and tellign me that I want it like that, I don't like them lying to me about their reasons for doing it, but the by-product of slowing life down ? I could live with that.
And people will say that their car is not comfortable or relaxed at slower speeds. They're probably right - but that's only a matter of gearing and all cars are geared for the market they are sold in.
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journies/journeys/whatever - I know what I meant, its just my fingers that were confused.
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Am I right in thinking that more energy is used making most cars than they burn during the "average" life of a vehicle.
If so why not give tax breaks to people who buy used cars and keep them on the road for longer through careful maintenance. Most of the components of my car have got years of useful life in them and it has no problem meeting the MOT emissions test, but my car is worth chuff all because of the fashion for changing cars so it's not worth spending on repairs. If I could offset the cost of repairs in some way against say reduced road tax, fuel tax and reduced insurance or no VAT on repairs the environment would benefit.
Obviously it's a lot easier to kid the public "we're on top of it" by building windmills in beautiful places.
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The drag force term in the road load equation is;
1/2 * rho * Cd * Area * Velocity^2
rho is the density of the air - you can't really change that
Cd is the much publicised drag coefficient
Area is the frontal area of your car
Velocity^2 is the velocity squared bit I mentioned above.
So, frontal area is just as important as drag coefficient. I suspect the Xantia has a lower frontal area as well as a lower drag coeeficient, so you gain twice!
Manufacturers who only quote Cd are really only giving half of the required infromation to enable people to estimate high speed fuel consumption.
Of course, the aredynamic drag force acting on your car isn't at all altered by your being in sixth gear! In terms of fuel consumption per bhp produced, it is not true to say that slower engine speeds are always better - there is an optimum speed, near to the max. torque engine speed.
Number_Cruncher
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but isn't it the case that the UK puts out something like 2% of the worlds CO2,
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lawman, you are right.
now imagine that tomorrow al-quaeda manage to blow up the whole of the uk with a nuclear bomb or whatever. then, from tomorrow, no more man-made co2 emissions ever fro the uk. and what difference will that make to the world? zilch. zero.
don't worry, chaps. china and india will make up our lost 2%contribution in just a few months.
carry on living and motoring. it is too late to worry about how much pollution mankind is creating. we are way past the tipping point. so go on, enjoy life. go ahead buy that x5 now, if that is what you want. don't wait for tomorrow.
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A couple of points:
Pollution per se is not just a matter of fuel consumption bit also how efficiently the fuel is burnt, most modern cars are pretty good in this regard however a petrol engined car geared at say 30mph/1000 rpm is not going to be burning it's fuel as completely at 70 mph (approx 2300 rpm) as at 100 mph (3300 rpm) even though it is using more fuel at 100 mph, hence CO2 might be less at 70 though unburnt HC's might well be less at 100.
Re the 747 analogy, comparing a car with one passenger and and intercontinental 747 flight the amount CO2 produced by the 747 per passenger mile is less:
A 747-400 can do 7000 miles on 200,000 litres of fuel carrying between 400 and 500 people, call it 400 to be conservative.
200,000 litres = 44,000 imp gals divided by 400 people = 110 gals per person. 7000 miles divided by 110 gallons = 63.6 mpg per person. Equal to a car car carrying 1 person at 63mpg, 2 people at 31.5 mpg etc.
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Ref 747 fuel consumption:
1. Long-haul flights, like the one you quoted, are indeed more economical in MPG terms. However, I can fit in a couple of 7000 mile flights in a weekend. It'd take me a mite longer than that to drive 14,000 miles.
2. Take off and climb uses hugely more fuel than cruising. Most flights are short haul and thus more polluting.
What matters is how much pollution is actually produced per person per year rather than per mile. A plane will prduce hugely more per person per year than I could ever manage in a car.
V
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It aslo distributes the CO2 rather higher in the atmosphere than an exhaust pipe and so the damaging effect is amplified.
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"It aslo distributes the CO2 rather higher in the atmosphere than an exhaust pipe and so the damaging effect is amplified."
The higher the better. I don?t want to be breathing it in while I?m strolling along eating a Big Mac.
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2. Take off and climb uses hugely more fuel than cruising. Most flights are short haul and thus more polluting.
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That is certainly true.
What matters is how much pollution is actually produced per person per year rather than per mile. A plane will prduce hugely more per person per year than I could ever manage in a car.
Again is is a matter of comparing a person flying v a person driving, not one plane v one car, the average person might do a couple of short haul or perhaps one long haul flight a year though they will also drive 15,000 miles a year, the latter is likely to be more polluting.
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I'd be far more impressed if the gov. ensured that we could travel at 70mph "to cut down on CO2 emissions". The nearly 8 hours it took me from Midlands to Dover a few weeks ago suggests that it wasn't exceeding 70, but failing to reach 30 mph that produced the most CO2.
Phil
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I see no problem with a strictly enforced 70mph limit for cars to reduce C02. By the same token, the same rules should apply to planes they should be limited to 70 mph as well to reduce CO2.
--
RF - currently 1 Renault short of a family
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This whole debate is laughable.
A politically-inspired leak appears in one of this morning's papers just to gauge public reaction to some of the more extreme ideas floating around in Whitehall, usually followed by something that doesn't go quite as far and therefore seems less extreme.
Strictly enforcing a 70mph limit could take us in all sorts of directions, but is it really where the CO2 battle is at?
Try something that does no miles an hour. It's called a house and it produces more CO2 than cars...
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MO,
The debate is not laughable, although it is not unheard of that government when introducing new policy come out with an idea so alien to the general public that we are grateful for any lesser evil.
To give people some idea of aviation fuel consumption:
A fuel pump on a large jet engine (Trent or RB211) can meter enough fuel to power 1500 1.6 litre Ford Focus at 70mph. That is an awful lot of fuel an many jets have four of these!
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A fuel pump on a large jet engine (Trent or RB211) can meter enough fuel to power 1500 1.6 litre Ford Focus at 70mph. That is an awful lot of fuel an many jets have four of these!
Maybe but again it has to be compared like for like, 4 RB211's can carry 400 + people at 550mph hence the mpg per person is comparable with a 1.6 Focus carrying 2 people.
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MO, The debate is not laughable, although it is not unheard of that government when introducing new policy come out with an idea so alien to the general public that we are grateful for any lesser evil. To give people some idea of aviation fuel consumption: A fuel pump on a large jet engine (Trent or RB211) can meter enough fuel to power 1500 1.6 litre Ford Focus at 70mph. That is an awful lot of fuel an many jets have four of these!
The 'debate' IS laughable. It isn't a debate at all. It's an almost comically obvious example of headline-grabbing gesture politics that doesn't come within a country mile of dealing with the underlying issues.
Homes produce colossal amounts of CO2, yet where there should be a sensible debate about how that can be reduced there is a shattering silence.
Instead of really doing something we're being fed some comedy 'policy' about you and me being the real culprit everytime we go past 70. Absolutely barking...
Imagine: the cost of a new policy, how it would be enforced, how you would measure it, whether, infact, it would be rendered completely irrelevant bythe steady march of different fuels and fuel efficient engines.
As for the slow-these-people-down-at-all-costs Nanny State...don't start me.
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"Homes produce colossal amounts of CO2, yet where there should be a sensible debate about how that can be reduced there is a shattering silence"
That's not altogether accurate but I suspect a debate on that is going to stray away from motoring issues rather quickly, but have a look at today's FT for some comments on this and it is a fact that transport (in all guises) is the fastest rising source of UK CO2 emissions.
I do agree with your first paragraph and I think that the 70mph idea is a good example of the kind of "sticking plaster" approach that passes for a meaningful energy policy in the UK
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Exactly. I heard somewhere that for every person on the planet there is one tonne of termites producing methane. They'll probably do more for climate change than most people are likely to either.
I suspect it is all to do with greenpeace dumping a load of coal (handy for these cold days ;-) ) on Bliar and it is nothing more than a knee jerk response to pretend to be interested in climate change. The only place to read sensible environmental reporting is on envirospinwatch greenspin.blogspot.com/
Concrete in new builds is one of the most damaging of all activities and yet prescott et al is wanting to building thousands of new homes. They'll do far more damage than a few people doing over 70 mph.
I think we should protest and sit in 4th gear at 70 instead of 5th/6th. Soon show them what a bunch of numpties they're being making a fuss over such a miniscule contributor to CO2. Besides if they were really that worried then they'd ban catalyst cars as they produce more CO2 per mile than non-cat cars do....
teabelly
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