RE: NEDC mpg tests don't lie: Tell Me I'm Wrong
Discussion
Fastdruid said:
I disagree. Having a real world test would mean manufacturers could concentrate on tuning for real world conditions rather than a tiny fraction of that.
The offshoot could be a *real* improvement rather than an on paper improvement.
Well put. Most people want to be told roughly what they can expect so they can budget accordingly. So many friends and colleagues have been frustrated and surprised to be so far from the publicised figures. Such a loosely qualitative comparison that shows how well cars play the system is useless. Removing spare tyres etc to reduce weight, taping up gaps for aero gains etc should not be allowed either, as is not a fair comparison between different manufacturers or models you might buy and use.The offshoot could be a *real* improvement rather than an on paper improvement.
Admittedly using a real route (eg driving 90 miles at 2am on a set route) would still leave anomalies as you would have roadworks and different weather conditions to contend with, not to mention different traffic conditions which all introduce variances. But unless a lab condition simulated much more stop/start/hill/wind than present, with much longer testing cycles to give PHEVs etc a more realistic range too, then I think the variances from on-road testing would be the best option at present.
They've sold over 4million hybrids in the US,a country where the most popular cars remain 4 and 6 cylinders despite no annual VED. They also have relatively accurate MPG tests, one where car makers have been fined and partial refunds offered to buyers when the carmaker has been found to be gaming these tests.
Every single argument Dan makes is spurious and wrong.
Countries can base taxes on co2 where cars ratings more accurately reflect real world mpg/emissions just as easily on an artificial easily gamed test.
Yes people care about emissions and even where they don't, that doesn't mean encouraging people to buy cars that emit less is a bad thing. Most people don't care about a plastic bag levy, recycling or congestion (beyond how it personally affects them) and many other examples that the age old Tragedy of the Commons attempts to illustrate.
Car makers in Europe have a disproportionate amount of power and influence (as do commercial makers). This is shown time and again when Europe tries to bring in more stringent emission rules, with them inevitably being watered down and pushed back. See for example the truck industries recent success. If car makers wanted a more realistic test they would have one, so to put the blame entirely on NEDC is wrong. Blah blah blah.
It's not that your view is controversial, it's simply that it's predicated entirely on very obvious fallacies and sounds like the kind of clarkson rant that would appear in tbr Daily Mail (I.e. far more ranty and silly than he usually is).
Every single argument Dan makes is spurious and wrong.
Countries can base taxes on co2 where cars ratings more accurately reflect real world mpg/emissions just as easily on an artificial easily gamed test.
Yes people care about emissions and even where they don't, that doesn't mean encouraging people to buy cars that emit less is a bad thing. Most people don't care about a plastic bag levy, recycling or congestion (beyond how it personally affects them) and many other examples that the age old Tragedy of the Commons attempts to illustrate.
Car makers in Europe have a disproportionate amount of power and influence (as do commercial makers). This is shown time and again when Europe tries to bring in more stringent emission rules, with them inevitably being watered down and pushed back. See for example the truck industries recent success. If car makers wanted a more realistic test they would have one, so to put the blame entirely on NEDC is wrong. Blah blah blah.
It's not that your view is controversial, it's simply that it's predicated entirely on very obvious fallacies and sounds like the kind of clarkson rant that would appear in tbr Daily Mail (I.e. far more ranty and silly than he usually is).
awarded said:
Qualitatively the figures do mean something to an extent. However, quantitatively it is very hard to draw an accurate conclusion from the data provided by manufactures. What people want to know is the difference in fuel cost between two cars based on the one they currently own. The official figures don't allow an accurate calculation.
People are unpredictable in a number of ways though, and what the vehicle and engine can do is a factor in what fuel economy they will achieve outside of what ultimate fuel economy the engine is capable of achieving. Not that that statement makes a huge amount of sense but bear with me...If you look at the trend of 2.0l diesels from BMW for instance. The first iteration in 1998 was 135PS and capable of ~50mpg combined on cycle. The next iteration of that engine went up to 150PS (~50mpg), then 163PS (~50mpg) and now the "normal" model is 190PS (~60mpg).
The cycle means the vehicle only operates in a window of speeds and loads, which as a percentage of operating range is getting smaller as engines get more powerful over time. If you give the average individual a vehicle which has a bigger performance envelope then the chances are they will use it which will hurt fuel economy. There have been a load of suggestions over the years that actually engines haven't got any better but they are just better at cheating the test. I disagree - engines are fundamentally capable of much better fuel economy than they were 10 years ago, but there is also more performance available to use at the same time.
kedaha said:
They've sold over 4million hybrids in the US,a country where the most popular cars remain 4 and 6 cylinders despite no annual VED. They also have relatively accurate MPG tests, one where car makers have been fined and partial refunds offered to buyers when the carmaker has been found to be gaming these tests.
No they don't, they are just as inaccurate but the EPA provide an adjusted fuel economy figure at point of sale which is more in line with sales expectations. This amounts to a percentage taken off the fuel economy achieved on the cycle.Fun fact, when the various commissions were coming up with the WLTP cycle which is to replace the NEDC in the coming years, they actually saw that cycle fuel economy got better or didn't change at all despite the cycle being many times more transient than an NEDC. Subsequent tweaking hasn't really made it a "better" cycle in that respect, because the problem isn't the cycle it's the boundary conditions of the cycle that cause the discrepancy.
Edited by zeppelin101 on Wednesday 21st October 10:27
Edited by zeppelin101 on Wednesday 21st October 10:27
Totally agree. I have to get from A-B I base my purchases on perceived cost of ownership, the fact that that also means probably the least polluting is a happy by product.
I used to run a Lexus LS430 that did low teens to 27ish mpg, but converted to LPG meant it was doing the equivalent of 35-50 mpg. It was still chucking out low teens worth of pollutants.
I'd buy a hybrid, not cos its eco friendly (debatable) but cos it cost less to run.
I used to run a Lexus LS430 that did low teens to 27ish mpg, but converted to LPG meant it was doing the equivalent of 35-50 mpg. It was still chucking out low teens worth of pollutants.
I'd buy a hybrid, not cos its eco friendly (debatable) but cos it cost less to run.
Disagree completely. If doing a regular motorway speed (130 km/h tacho, 121-122 km/h fo'real) in a 'tax exempt' NEDC special (that's you, Fiat Twin Air) results in the same fuel consumption as doing the same, in the same place, in utterly similar conditions in a V8 sports car that I would have to pay SIXTY THOUSAND euro CO2-related taxes for if I bought and registered it here new, the system is broken.
And I won't get into the plug-in hybrid scam that is built entirely on the fact that the NEDC test takes no account of electricity useage whatsoever. Build the biggest tank feasible, equip it with a relatively weedy ICE and a battery just big enough to last the test and presto, <50g/km CO2 emissions (on paper)!
Unrealistic as it is, the test itself I have no problems with. I do have problems with the legislation and taxation consequences driving engine and car development into an evolutionary dead end.
If the aim was energy conservation in the real world, we would build lower, lighter, more aerodynamic cars with engines that would be most efficient at typical open road cruising speeds and acceleration rates that go with the general pace of traffic, not high-rise, square boxes with engines downsized to the point that they need forced induction assistance with lambda values dropping as low as 0.8 to keep things cool, if any more than glacial acceleration or town speeds is being asked for.
Alas, politicians are more concerned with creating a parallel universe on paper than creating a more sustainable economy, and car manufacturers - having been held responsible for everything that's wrong in the world since the 1970s, are far too eager to please.
And I won't get into the plug-in hybrid scam that is built entirely on the fact that the NEDC test takes no account of electricity useage whatsoever. Build the biggest tank feasible, equip it with a relatively weedy ICE and a battery just big enough to last the test and presto, <50g/km CO2 emissions (on paper)!
Unrealistic as it is, the test itself I have no problems with. I do have problems with the legislation and taxation consequences driving engine and car development into an evolutionary dead end.
If the aim was energy conservation in the real world, we would build lower, lighter, more aerodynamic cars with engines that would be most efficient at typical open road cruising speeds and acceleration rates that go with the general pace of traffic, not high-rise, square boxes with engines downsized to the point that they need forced induction assistance with lambda values dropping as low as 0.8 to keep things cool, if any more than glacial acceleration or town speeds is being asked for.
Alas, politicians are more concerned with creating a parallel universe on paper than creating a more sustainable economy, and car manufacturers - having been held responsible for everything that's wrong in the world since the 1970s, are far too eager to please.
Q
Um, yes, that would be why VW are facing criminal investigation around the world, and was a totally different test. This is not about what VW did to break the law but complaints about the perceived inaccuracies of MPG tests, not faking emissions tests.
Cotic said:
Article said:
...generally ill-informed but incredibly self-righteous stories about how the carmaking mega corporations lied to us.
They didn't really. They just engineered their cars to play the system...
Woah - hang on. My understanding is that VW developed software to purposely detect a rolling road, and therefore to give grossly misleading results to avoid the fitment of an expensive AdBlue system. That's more than just 'playing the system', surely? Taping up shut lines, running the car with the minimum of fuel, even removing the spare wheel - that's playing the system.They didn't really. They just engineered their cars to play the system...
Of course official MPG figures have no bearing on reality. This has already been proven and tested.
I think I still have an issue of a car mag where they tested city cars (Fiesta size) and not one made claimed mpg. Worst one consumed over 1.5l / 100km more than stated.
I mean lets be serious. How car a over 1.7 tonne 5 meter car with 3 liter 272bhp diesel do over 50mpg combined? Magic?
I think I still have an issue of a car mag where they tested city cars (Fiesta size) and not one made claimed mpg. Worst one consumed over 1.5l / 100km more than stated.
I mean lets be serious. How car a over 1.7 tonne 5 meter car with 3 liter 272bhp diesel do over 50mpg combined? Magic?
We all know the figures are out, but it all depends on the driver and where you drive.
As I said in a previous post I get 27 mpg avg compared to 25 quoted. But I see 40 mpg when I drive down the a9 due to be a average speed camera zone for the length of it. The higher mpg figure for my car only sees 30/31.
As I said in a previous post I get 27 mpg avg compared to 25 quoted. But I see 40 mpg when I drive down the a9 due to be a average speed camera zone for the length of it. The higher mpg figure for my car only sees 30/31.
Actually, I don't accept that the tests necessarily are a valid basis for comparison.
Testing two cars in conditions under which you never drive does not mean that A will be more economical than B under the conditions in which you do drive.
As I understand it, these tests are mainly conducted at sub 30mph speeds – which actively favour smaller engined, hybrid and/or diesel cars.
However, if your usage is mainly motorway the real world differences may turn out not to be that great since larger engined vehicles are proportionately more efficient at higher speed.
I once had use of a 1.2 VW Polo at a time when my own car was a Volvo V70 2.5 petrol auto.
On paper the Polo was vastly more efficient and, of course, around town the tiny VW trounced the Volvo on mpg but on a long motorway journey there was almost nothing in it.
So “Tests Schmests” I say - it still remains a case of horses-for-courses.
But, as ever, your mileage may vary.
Testing two cars in conditions under which you never drive does not mean that A will be more economical than B under the conditions in which you do drive.
As I understand it, these tests are mainly conducted at sub 30mph speeds – which actively favour smaller engined, hybrid and/or diesel cars.
However, if your usage is mainly motorway the real world differences may turn out not to be that great since larger engined vehicles are proportionately more efficient at higher speed.
I once had use of a 1.2 VW Polo at a time when my own car was a Volvo V70 2.5 petrol auto.
On paper the Polo was vastly more efficient and, of course, around town the tiny VW trounced the Volvo on mpg but on a long motorway journey there was almost nothing in it.
So “Tests Schmests” I say - it still remains a case of horses-for-courses.
But, as ever, your mileage may vary.
900T-R said:
Disagree completely. If doing a regular motorway speed (130 km/h tacho, 121-122 km/h fo'real) in a 'tax exempt' NEDC special (that's you, Fiat Twin Air) results in the same fuel consumption as doing the same, in the same place, in utterly similar conditions in a V8 sports car that I would have to pay SIXTY THOUSAND euro CO2-related taxes for if I bought and registered it here new, the system is broken.
If you cherry-pick a scenario carefully enough, then you can draw whatever conclusions you like from it.Use both those vehicles in the same way, day-in-day-out, and tell me they both use the same fuel.
TooMany2cvs said:
The one caveat has to be that it doesn't really seem to reflect hybrids accurately.
If we're going to get / our taxes are all enviro-b
ks it would seem something should be added to include the real through life environmental cost of all cars including creation and disposal. That would stop the hybrid owners acting so pious.Fetchez la vache said:
If we're going to get / our taxes are all enviro-bks it would seem something should be added to include the real through life environmental cost of all cars including creation and disposal.
Hmm. Not easy to calculate. Do you hit a new car buyer with a retrospective tax if they write it off, so the life was much shorter than expected?ks it would seem something should be added to include the real through life environmental cost of all cars including creation and disposal. Fetchez la vache said:
That would stop the hybrid owners acting so pious.
...ba-doom-tish...TooMany2cvs said:
Fastdruid said:
Having a real world test would mean manufacturers could concentrate on tuning for real world conditions rather than a tiny fraction of that.
Lovely, in theory. But you go away and define a "real-world" test that's infinitely reproducible across every car from every manufacturer from every country, and isn't open to gaming by manufacturers... Even if you can, you'll still get the ham-footed muppets and half-mile-commute brigade complaining they don't get the figure, so it must be rigged.And complaining about the 'ham footed muppets' or 'half-mile-commuters' is silly. If those conditions were included as part of the test, you bet your b
ks that the manufacturers would spend time optimising the cars performance for those scenarios and again, we'd all benefit.This is a daft article confusing emissions with fuel efficiency in the wake of the VW scandal.
The two are very separate things.
The VW cars could achieve good fuel economy under standard testing and probably not too bad on the road too, but this is only if the defeat device was activated to stop the filters and catalytic converters from working.
VW wanted to have their cake and eat it. The only way they could create cars with low emissions for regulatory purposes was by adding the filters and catalytic converters, but when these additions are in use during driving it increases the fuel use of the car, so they implement software to turn this off during testing to get better fuel economy.
Let's be clear here, VW is at fault, not anyone else. VW can achieve the low emissions required legally, with the filters and converters, but they also want to sell cars that are fuel efficient and they can't seem to create a car that is both.
You either drive the car with the defeat device activated (as they did during testing) and release 20X more bad emissions in the atmosphere or release fewer emissions and get lower fuel efficiency. I think VW should have stuck to the latter proposition instead of trying to claim they achieved both.
The two are very separate things.
The VW cars could achieve good fuel economy under standard testing and probably not too bad on the road too, but this is only if the defeat device was activated to stop the filters and catalytic converters from working.
VW wanted to have their cake and eat it. The only way they could create cars with low emissions for regulatory purposes was by adding the filters and catalytic converters, but when these additions are in use during driving it increases the fuel use of the car, so they implement software to turn this off during testing to get better fuel economy.
Let's be clear here, VW is at fault, not anyone else. VW can achieve the low emissions required legally, with the filters and converters, but they also want to sell cars that are fuel efficient and they can't seem to create a car that is both.
You either drive the car with the defeat device activated (as they did during testing) and release 20X more bad emissions in the atmosphere or release fewer emissions and get lower fuel efficiency. I think VW should have stuck to the latter proposition instead of trying to claim they achieved both.
I've never had any trouble matching or bettering the NEDC figures with every car I've ever owned, I think much of the problem is that most people just don't understand simple physics and are hopeless at driving efficiently. Just look around (or even at yourself) to see all the muppets tailgating and jumping on the brakes every 10 seconds, zooming up to red lights and queues, braking to 5mph for every corner, idling for hours outside the school gates etc and it's no wonder everyone gets crap economy.
The other factor worth considering is maintenance. I use top quality tyres not chinese cack, check my tyre pressures religiously when cold rather than at the garage when hot, service cars excessively using top quality oils etc. How many people are driving around with half flat chinese tyres and engine oil that's done 50k?
I've not owned a modern diesel I will concede, maybe they are worse. The old diesels I've owned have easily bettered their quoted figures though (2x 4.2l I6 TDI Landcruisers and one 3.0tdi Hilux Surf).
The other factor worth considering is maintenance. I use top quality tyres not chinese cack, check my tyre pressures religiously when cold rather than at the garage when hot, service cars excessively using top quality oils etc. How many people are driving around with half flat chinese tyres and engine oil that's done 50k?
I've not owned a modern diesel I will concede, maybe they are worse. The old diesels I've owned have easily bettered their quoted figures though (2x 4.2l I6 TDI Landcruisers and one 3.0tdi Hilux Surf).
TooMany2cvs said:
If you cherry-pick a scenario carefully enough, then you can draw whatever conclusions you like from it.
Use both those vehicles in the same way, day-in-day-out, and tell me they both use the same fuel.
If I wanted to cherry-pick, I'd have mentioned the dismal fuel consumption of the Twin-Air engined Lancia Ypsilon on the German Autobahn at indicated speeds of 150 km/h (6.6-7 km/litre) and 170 km/h (4.4-4.6 km/litre) - figures that are easily bettered by my 22 year old TVR, let alone the diesel hack. Use both those vehicles in the same way, day-in-day-out, and tell me they both use the same fuel.
The point is that I don't have my cars for running about in cities - I have got two functional legs for that purpose - and the motorway scenario actually applies for about 90% of my mileage covered, as it does for most people here that aren't complete car potatoes. Optimising cars for a scenario that knows many better alternatives doesn't strike me as especially enlightened. But then again maybe I'm thinking about these things in a way that's deemed too holistic for this convenience- and indifference-driven society.
Americans don't like Dielsels. Thus they create standards that favour petrol over diesel.
NoX fumes are not the issue.
Solution do not sell dielsels to Americans.
Seeing as Americans buy over 1 million sub 20 mpg cars a year, they have as ususal missed intentionally the point.
It would be nice if they investigated domestic companies with the same enthusiasm as they like to investigate and fine foreign companies.
NoX fumes are not the issue.
Solution do not sell dielsels to Americans.
Seeing as Americans buy over 1 million sub 20 mpg cars a year, they have as ususal missed intentionally the point.
It would be nice if they investigated domestic companies with the same enthusiasm as they like to investigate and fine foreign companies.
An objective test is good. What is, however, missing is (as in all good science)a test that at the same time checks the correlation between the test and real conditions. A car that produces good test results but lousy real results (VW) should be penalized in relation to a car that has a good correlation between the test and reality.
And this is the responsibility of the government.
Thinks evolve over time. First manufacturers produced there own mpg etc. Then all vehicles became subject to a standardized test an now comes the progression to a reality correlated test....
Simple.
And this is the responsibility of the government.
Thinks evolve over time. First manufacturers produced there own mpg etc. Then all vehicles became subject to a standardized test an now comes the progression to a reality correlated test....
Simple.
Gassing Station | General Gassing | Top of Page | What's New | My Stuff