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Nearly all new diesel cars exceed official pollution limits

theguardian.com

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Re: Nearly all new diesel cars exceed official pollution limits

#21

Post by InclinedPlane »

verytrivial wrote: post #17

I'm willing to take down votes for this position, I don't understand the fuss here, nor to credulity of the actors whom should have (and probably did) know better. If the tests were meant to reflect real-world conditions, they should be be designed to do that -- they clearly weren't, and were only tiny sample of performance from which (wild?) extrapolations were drawn. Don't have a cry about it, fix the tests. Get to…

Diesel vehicles kill people, period. It's very difficult to reduce emissions sufficiently to change that but it's nigh impossible to ban diesel cars and trucks from the road. Given that, the only reasonable alternative is stringent tests that push diesel technology to the limit in terms of minimizing health impact. Which is what we have. Could the tests be better? Certainly. But that doesn't excuse the cheating. Imagine if airplane manufacturers had been found to be cheating on safety tests. That's how serious and how immoral this cheating is.

Re: Nearly all new diesel cars exceed official pollution limits

#22

Post by MagnumOpus »

awjr wrote: post #19
verytrivial wrote: post #17

I'm willing to take down votes for this position, I don't understand the fuss here, nor to credulity of the actors whom should have (and probably did) know better. If the tests were meant to reflect real-world conditions, they should be be designed to do that -- they clearly weren't, and were only tiny sample of performance from which (wild?) extrapolations were drawn. Don't have a cry about it, fix the tests. Get to…

There is a lot more riding on these tests than is currently being admitted. The simple fact is that based on the tests and the impact of NOx on population health, the sale of diesel cars should be stopped immediately. Even London has doubled the congestion charge fee for diesels. A further step would be to recognise that petrol cars also emit NOx and that the long term goal should be the removal of these from the roa…

> The simple fact is that based on the tests and the impact of NOx on population health, the sale of diesel cars should be stopped immediately

Extremely disingenous. You know what happens when the sale of diesel cars/taxis/buses stops? The old ones get driven longer.

You know what vehicles create the lion's share in NOx emissions? The ones built and sold before 2000 when Euro3 emission standards started limiting NOx emissions. The majority of London "quaint" TX4 black cabs are of this toxic variety, as are the majority of their buses. (This is probably similar to much of the rest of Europe). Taking 50 new diesel vehicles off the street will do less than upgrading a single one of these legacy vehicles to a state-of-the-art diesel engine. Your proposed policy would be counterproductive.

Re: Nearly all new diesel cars exceed official pollution limits

#23

Post by mhw »

While it makes good headlines, I think most of this could be summed up as "vehicle emissions are more complex than the simple model you might expect".

Go and read the Wikipedia page on the New European Driving Cycle - https://en.wikipedia.org/wiki/New_European_Driving_Cycle. Notice that in the test procedure every instance of acceleration is described as "the car slowly accelerates". Now think about the range of driving styles that are found in the real world. Some people might be quite laid back about accelerating, but I think there's an awful lot of "floor the accelerator to get back up to the speed limit" as well. It's hardly surprising that in those periods the emissions from the engine will be higher than they were under the test cycle.

So who do we blame? The vehicle manufacturers? Well, given current popular sentiment, down that path may lie vehicles which are designed to never exceed the emission limit. At the extreme end we might finish up with cars that automatically throttle back when they hit an emission limit, similar to processors throttling back when they hit thermal emission limits. But what do we do when we start having fatal accidents when people tried to overtake and the engine suddenly reduced power in an unpredictable way because it had gone over the emission limit?

So, blame the emissions tests? Well, what should the emissions test be targeting? Never going over a particular threshold, say? In which case, how do you define a standard protocol (to ensure fairness across vehicles) that all vehicles will be able to follow? At one end you've got cars like the Peugeot Bipper Tepee with a 0-60 time north of 16 seconds (with both petrol and diesel engines - http://www.honestjohn.co.uk/carbycar/peugeot/bipper-tepee-20...). At the other you've got cars like the BMW X5 4.4 V8 which can accelerate roughly twice the mass in a quarter of the time (http://www.honestjohn.co.uk/specs/detail/?v=MBMWI-X50311 - the diesel engined version isn't far behind either). I'd imagine that a protocol that produces the highest emissions from the BMW would not even be achievable by the Peugeot.

The only other party left to blame seems to be the drivers, and particularly their inability or unwillingness to drive in a style that minimises emissions (and at the same time most likely increases fuel economy). But the media seem reluctant to point the finger in that direction.

I think we need to blame all of the above, but we need to get past the simplistic model of emissions being a constant that you can set a limit on for all vehicles regardless of how they are driven.

Re: Nearly all new diesel cars exceed official pollution limits

#24

Post by zo1 »

MagnumOpus wrote: post #22
awjr wrote: post #19

Earlier quoted context omitted.

There is a lot more riding on these tests than is currently being admitted. The simple fact is that based on the tests and the impact of NOx on population health, the sale of diesel cars should be stopped immediately. Even London has doubled the congestion charge fee for diesels. A further step would be to recognise that petrol cars also emit NOx and that the long term goal should be the removal of these from the roa…

> The simple fact is that based on the tests and the impact of NOx on population health, the sale of diesel cars should be stopped immediately Extremely disingenous. You know what happens when the sale of diesel cars/taxis/buses stops? The old ones get driven longer. You know what vehicles create the lion's share in NOx emissions? The ones built and sold before 2000 when Euro3 emission standards started limiting NOx…

I think the person you're responding to meant some sort of "immediate action", not necessarily just stopping the sale of new diesel cars. Precisely because we have to be sensible about the actual culprits of emission.

Re: Nearly all new diesel cars exceed official pollution limits

#25

Post by joosters »

_yosefk wrote: post #5

"Unlike other parts of the world, European nations incentivised the use of diesel vehicles over the last 20 years because they emit less carbon dioxide per mile than petrol cars. Governments thought stricter regulation would sharply reduce NOx emissions, but carmakers found ways around the rules and governments failed to clamp down on the practices." How typical in so many ways (I particularly like the claim that gov…

Without the governments' attempts at controlling pollution, do you really believe that the car companies would voluntarily be restricting their cars' emissions?

Re: Nearly all new diesel cars exceed official pollution limits

#27

Post by Shivetya »

walrus01 wrote: post #16

Now I wonder what the diesel emissions of a 20 year old ford f350 are. A lot, I imagine.

Well it wasn't that long ago that a study found that school buses had many times the acceptable levels of pollutants inside because they sat idling while waiting for kids.

All I have to do is watch the local bus service, mostly the city one, to see how bad some vehicles pollute. So let us be honest here, the government needs to clamp down hard on all vehicles in its employ at all levels even more than going after consumer cars

Re: Nearly all new diesel cars exceed official pollution limits

#28

Post by Shivetya »

mhw wrote: post #23

While it makes good headlines, I think most of this could be summed up as "vehicle emissions are more complex than the simple model you might expect". Go and read the Wikipedia page on the New European Driving Cycle - https://en.wikipedia.org/wiki/New_European_Driving_Cycle . Notice that in the test procedure every instance of acceleration is described as "the car slowly accelerates". Now think about the range of dri…

Well motortrend has this real world mileage test where they hook up an complex looking device to the back of the car. Something like that surely can be employed by manufacturers, magazines, colleges, etc, and the EPA.

From reading the article it should not be difficult to extend the testing abilities to cover all pollutants you want to measure

http://www.motortrend.com/news/real-numbers-mpg-101/

Re: Nearly all new diesel cars exceed official pollution limits

#29

Post by D_Alex »

f_allwein wrote: post #2

> There is no suggestion that any of the cars tested broke the law on emissions limits or used any cheat devices. Since all these cars passed the laboratory test, that means there must be something very wrong with the test and the way the standards are enforced. Or all car makers do cheat.

>Since all these cars passed the laboratory test, that means there must be something very wrong with the test and the way the standards are enforced.

It depends how the law is written.

Case a) - the cars must never emit more pollutants than specified in these rules - then yes, you are correct. The car manufacturers would be rightly concerned about the wide range of situations they would need to account for.

Case b) - the cars must not emit more than the specified amount of pollutants under these specific test conditions (implying hopefully "we understand that the real world performance will differ, and are willing to accept this for the sake of simplicity in testing/lawmaking") - in this case the system is working as intended.

I am not sure which case we are dealing with, maybe someone can advise us.

Re: Nearly all new diesel cars exceed official pollution limits

#30

Post by teh_klev »

makomk wrote: post #18
andy_ppp wrote: post #10

Ouch, that's gotta hurt: "Surprisingly, the tiny number of models that did not exceed the standard were mostly Volkswagens"

Not terribly surprising. Their engineers are competent, it's just that the US (where diesels are less popular) set some rather unpleasant requirements for diesel cars, in particular insisting that they couldn't require the diesel exhaust fluid tank to be topped up by the end user and setting lower NO2 limits. In order to meet these conflicting requirements, VW cheated. I think some of the VWs they tested actually hav…

> in particular insisting that they couldn't require the diesel exhaust fluid tank to be topped up by the end user

Not being rude, but I'm having trouble parsing that part of your comment.

Do you mean that the US authorities won't let diesel car owners re-fill the diesel exhaust fluid tank by themselves, i.e. the re-fill must be performed by a dealer?

Also is the DEF tank just a US thing? I'd never heard it before (UK resident here).

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