Diesel Cars

[jacks09]

I was never really educated on the differences between petrol and Diesel cars, and have owned both. From my own limited reading i can gather that government pushed Diesel cars a while ago and now look as if though they will retract that thinking and maybe even offer a scrappage service for Diesel cars.

Are they really more polluting than a petrol?

Are there "performance" differences?

Is a scrappage scheme a good idea?

[Nigello]

They produce less CO2 - a global warming gas - but produce more NO2 - the stuff that aggravates breathing difficulties, etc. The latter was not known, apparently, when a previous government wanted to promote diesel use to "save the planet".

Some have said a scrappage scheme would be a good idea but others say it may penalise those who live in rural areas, where pollution is not as big an issue. Also, it may be a better idea to offer upgrades to converters, etc, to diesel drivers but others say this would not work.

Taxis, lorries and buses would be the ones to go after, some say, whereas others would argue that getting rid of speed bumps and certain traffic lights would work best because the vehicles would then not be slowing down and speeding up, thereby causing more pollution to be produced.

The above is a sketch of the main ideas, solutions and drawbacks so please add to it and correct as necessary!

[rendelharris]

Briefly:

- Diesel cars theoretically produce less Co2 than petrol cars, so are better for the global environment - that's why the government offered a tax break to buy them, as they were struggling to meet our EU obligations to reduce carbon emissions. However, recent studies ( https://www.theguardian.com/environment/2016/feb/19/diesel-cars-may-be-be-worse-than-petrol-for-co2-emissions-report-claims ) have shown that in fact diesels may be as bad or worse for Co2, as their filters can clog (especially in urban driving) and they can be removed to increase performance. At the same time diesels produce No2 (nitrogen dioxide), which is basically a poison, and particulate matter which is what contributes to "on the ground" pollution causing breathing problems, developmental problems and premature deaths (around 40,000 per year in the UK).

- It certainly used to be the case that diesels were more economical, as diesel fuel has a higher energy content and converts more of that energy into useful work. However, advances in petrol engine technology have cut back on that advantage until it's almost unnoticeable in ordinary urban driving. For longer motorway type driving diesels still generally have better economy. Conversely, in terms of performance, petrol cars were always faster but improvements in diesel technology have removed a lot of that advantage. In terms of financial economy, diesel's more expensive than petrol (more so here than in Europe) and may become more so still if proposed levies are brought in. With diesel cars being more expensive to buy and having greater depreciation petrol seems to be the choice for overall economy at the moment.

- A proper scrappage scheme would be a good idea, i.e. one that would have some effect, but last I saw the government were proposing to offer to replace the 15,000 worst polluting diesel cars with electric or hybrids (actually only offering ?8,000 per vehicle to do this): given that there are over twelve million diesel cars in Britain, how they think this will have any more than a homeopathic effect is not entirely clear.

It is unfair on diesel drivers who bought their cars in good faith when the government was encouraging their purchase as "green" vehicles, and better compensation should be offered to those who will lose out. But if we're going to have the slightest chance of improving the air quality in our cities (can you imagine anything else being allowed to cause 40,000 premature deaths and just be accepted as normal?) then diesels are going to have to go - that includes, of course, HGVs, buses and trains. ETA crossposted with Nigello - as s/he pointed out, taxis are a big problem as well, especially in London.

[Jeremy]

Diesel and petrol emissions are different. As Nigello says, diesel is more efficient, so produces less carbon emissions, but they produce other nasty staff .. NO2, and smoke particles.

As for performance, diesel engines tend to have more torque, so you can accelerate or climb hills more easily without having to rev the engine as much. Even if they look slower on paper (0-60 speed, etc).

I think a hybrid is the way to go. In theory you should get the torque and fuel efficiency of the diesel, with lower emissions than either. If you're lucky enough to have off-street parking, a plug-in hybrid would seem like a no-brainer.

[BrandNewGuy]

There are problems with the headline figure that 40,000 premature deaths are caused by air pollution (and that's all air pollution, indoor and out, and not just vehicle emissions) in that it really refers to loss of life expectancy rather than something as brutal as killing you. And that loss of life expectancy for many of that 40,0000 might only be a few days over a lifetime, which is regrettable but not quite the impact of "kills 40,000 people a year", which is what many people interpret the phrase to mean.

I'm all for reducing air pollution as it's clearly been shown to be harmful, but I'm unhappy with being potentially misleading with the statistics just because it's for a perceived good reason.

[This is not having a go at Rendel, but at how these figures get passed about by the media]

[rendelharris]

BrandNewGuy Wrote:

-------------------------------------------------------

> There are problems with the headline figure that

> 40,000 premature deaths are caused by air

> pollution (and that's all air pollution, indoor

> and out, and not just vehicle emissions) in that

> it really refers to loss of life expectancy rather

> than something as brutal as killing you. And that

> loss of life expectancy for many of that 40,0000

> might only be a few days over a lifetime, which is

> regrettable but not quite the impact of "kills

> 40,000 people a year", which is what many people

> interpret the phrase to mean.

>

> I'm all for reducing air pollution as it's clearly

> been shown to be harmful, but I'm unhappy with

> being potentially misleading with the statistics

> just because it's for a perceived good reason.

>

>

Yes I agree it can be overdramatised! It's well nigh impossible to quantify, the authors of Royal College of Physicians report put the number as roughly 450,000 years of life. But that could be 45,000 people dying ten years early, 450,000 people dying a year early, a million people dying six months early...the actual calculations are massively complex and impossible for a layman (well this layman, anyway) to understand. It's an average, not a definitive figure. Of course nobody can ever attribute this sort of death with absolute certainty, any more than one could say the seventy-year-old smoker who died of lung cancer definitely wouldn't have had lung cancer if she hadn't smoked.

More worrying in its way I think is the relationship between pollution and asthma, obstructive pulmonary disease, child development etc. I'm not really bothered if I live to seventy-five or eighty-five (might change my mind nearer the time of course!) but I'm very bothered about children growing up with stunted lung capacity, asthma etc, and all the follow-on problems to which that can lead.

[TE44]

Gas and coal big winners in electricity capacity auction.2017-2018

https://www.ft.com/content/1e3d6e34-ea84-11e6-893c-082c54a7f539

Spring budget hitting the solar industry, makes

no sense.

https://www.theguardian.com/environment/2017/mar/06/solar-powered-schools-bill-business-rates-rise-england-wales

[Borky]

Renewables have a funny old return profile that ensures Kapital will not invest unless given increasingly large wedges of cash

[TE44]

This move to charge for already installed solar panels is discouraging and unfair.

It shows this goverment do not care about

our health. At the same time many of the free

schools are charities therefore exempt from

this tax. High on the goverments agenda, feels like anything that hasn't happened, they will do everything in there power to push it through, regardless of what people want.

The returns will be cleaner air.

Edit to make post clearer

[Villager]

Diesel cars produce???

15 per cent less CO2 than petrol,

400 per cent more NO2 and NO

2200 per cent more particulates, (tiny particles that penetrate the lungs, brain and heart)

The diesel problem has been made worse by two factors?

1. Car manufacturers using cheat devices in their cars which make it appear they are meeting emission standards but are in fact exceeding limits by up to 700%.

2. Diesel cars on short runs fail to reach the optimum operating temperature As a result the emission control systems are totally ineffective. The catalytic converters only become effective when they reach high temperature. Similarly with the fuel control systems inject a richer fuel mixture until the engine warms up. Under these conditions these engines emit up to 8 times their regular levels of pollutants.

[malumbu]

OK time for some myth busting.

Government did not say "go out and buy diesel" they incentivised low carbon cars to help save the planet. People (including me) bought diesels because they were fuel efficient, low-end torque, less stressed, reliable etc. There are other relatively low carbon cars - the Fiat 500 (petrol) is an ace city car. Yet even with that model Fiat had to extend it (in size) and bring in diesel variants.

We didn't buy diesels 20 years ago as they were awful. Noisy, slow, agricultural, take for ever to start. The French used them in country areas - not us Brits of course. The Sierra had one diesel variant, and that was with a 3L Peugeot engine (compare that to the Mondeo).

Then came along the common rail injection system and wow, you'd have to put a label on telling that it was a diesel or you may fill it with petrol.

Energy output is much higher on a diesel, but combustion is less complete. The fuel/oxgen ratio is differnt to that of petrol so you can't use three way catalysts. The Americans probably due the the great LA smogs of the 70 realised the need to clean up petrol engines which led to the end of carbureters and the introduction of the aforementioned three way cats. (And helped kill off the Brit small sports car industry, but it was pretty rubbish at that time).

The increased particulate matter emissions from diesels have been know for years, which is why all modern diesel cars have filters on them, with the trapped material being periodically burned off. Very successful, apart from the occasional one where it has either failed or been illegally used. You could have a go at government, police or local authorities for not doing more about smoky exhausts. Or the rrsses who don't care. Go back 25 years and you will have seen much more crap in the air.

There is no set amount that diesel cars are more polluting that petrol. All depends on the technology and the engine mapping - balance of performance, fuel use and NOx. It's wrong that vehicles are often optimised for the first two, but that is what sells cars. If as consumers we'd asked for low pollution at the expense of performance then the world would be different. But then we'd all be like me who uses a push bike as the main form of transport. VW make some excellent vehicles, have a massive R&D programme so it beggars belief that they cheated. The VW group are the only ones to date who have been shown do do so, and I doubt if it is a log jame.

There are no specified emission control systems. Some new vehicles use catalyst, others NOx traps, others exhaust gas recirculation. Or combinations. Depending on how these are plumbed in can help emission reductions. Some manufacturers say they can do it simply by engine mapping. It will all come out in the wash in times to come. Modern direct injection petrol engines may be the next environmental nightmare out there.

To date the emissions control regime for diesels hasn't delivered for cars and vans - but has been given a massive kick up its arse so will do. Yet for trucks and buses the new standards have delivered what they say on the tin, so with money and the space to bring in a chemistry kit it can be made to work. (see the Dutch NGO testing organisation TNO https://www.tno.nl/en/collaboration/expertise/technical-sciences/tno-research-on-powertrains/)

The health impacts of most air pollutants have been known for some time. We have got rid of sulphur and lead emissions. The impacts of NO2 are now much better understood. This is not a conspiracy theory as the Grauniad makes out.

So who's to blame. Government for not putting out better advice? And being afraid of the motor and petrol heads lobby?

Local authorities for some pretty wishy washy air quality strategies and communications. Low Emisison Zone was a start but why on earth not have progression in the standards rather than fix them six years ago.

The auto industry for doing the least they have to do in terms of meeting standards, not promoting environmentally friendly vehicles (or greenwash using 'eco' inappropriately, and promoting fast and sexy vehicles? Noting that the auto industry has been seen as a great British economic success in recent times and emplys tens of thousands - being out of a job is not good for your health.

The beaureau and Eurocrats for getting the standards wrong?

The health research community for not getting advice out swifter.

Or us for our obsession with speed and power, driving two tonne vehicles with one person in it badly and at times unecessarily.

Not that simple eh? And what are you going to do about it!

I'm using my diesel car less and less (yes I have one, it is reliable and economic), to the extent that when it falls apart or gets banned I'll consider alternative forms of propulsion and/or ownership and continue to use my pushbike as number one transport. It wont stop the family on the street from owning five cars, and everytime one of their kids hits 17 another one will come on the street.

Anyway apart from my jibe at the neighbours no selective use of numbers here.

And if I wanted to have a proper moan I'd say why are we also afraid of the black cab lobby.

Oh here is some data (the company who unearthed the VW scandal, so I expect pretty reliable) showing that slowly it is betting better http://emissionsanalytics.com/real-driving-emissions-how-real-is-it/

[stringvest]

I'm a bit peeved, as I went to look at a diesel car, but with the "pollution hype/ dilemma" went for the petrol thinking it would be less polluting and less tax, NO! 520 pounds in band L. Apparently there was an announcement about re-banding polluting cars THREE YEARS AGO. Was I out that day, was I expected to remember?

[tomdhu]

Many people switched to diesel in the 90's and naughties because it was a lot cheaper per litre then and you got much better mileage with diesel. When it got popular, the Gordon Brown upped the excise duty on diesel and it has now become about 2-3pence a litre more expensive than petrol for the last few years.

This has increased haulage costs as all trucks are diesel. Diesel in the UK is much more expensive than in Europe so foreign hauliers coming into the UK have installed bigger tanks and top up before leaving the Continent. That way they never need to buy our expensive fuel.

The Chancellor did it, Guv.

[malumbu]

There's this great information source called the internet which tells you about everything. Here's some information about petrol cars with low carbon emissions

http://www.nextgreencar.com/emissions/low-emission-cars/petrol/

Perhaps this interwebnet thingy will catch on.

This may be of interest too http://www.nextgreencar.com/emissions/low-emission-cars/petrol/

At 500 odd quid this must be some real muscle car. Bet is sounds good.

[Cardelia]

malumbu Wrote:

-------------------------------------------------------

> OK time for some myth busting.

>

> Government did not say "go out and buy diesel"

> they incentivised low carbon cars to help save the

> planet. People (including me) bought diesels

> because they were fuel efficient, low-end torque,

> less stressed, reliable etc. There are other

> relatively low carbon cars - the Fiat 500 (petrol)

> is an ace city car. Yet even with that model Fiat

> had to extend it (in size) and bring in diesel

> variants.

At the time, low CO2 emissions were synonymous with diesel because there were virtually no low-CO2 petrol/LPG/hybrid cars around. So it's a bit disingenuous to say that the Government weren't promoting diesel. They were, just not explicitly.

Additionally, the negative health effects of NOx and carbon particulates have been known about for decades. The government of the time decided that CO2 was a more pressing problem to solve than air quality. They were mistaken. If they'd listened to proper scientific advice at the time then they may not have been so keen on saving the planet at the expense of people's health.

> Then came along the common rail injection system

> and wow, you'd have to put a label on telling that

> it was a diesel or you may fill it with petrol.

Don't underestimate the effect of improved turbocharger technology. How many normally aspirated diesel engines do you see nowadays?

> The auto industry for doing the least they have to

> do in terms of meeting standards, not promoting

> environmentally friendly vehicles (or greenwash

> using 'eco' inappropriately, and promoting fast

> and sexy vehicles? Noting that the auto industry

> has been seen as a great British economic success

> in recent times and emplys tens of thousands -

> being out of a job is not good for your health.

I think you're being a bit unfair here. Technology advances don't grow on trees, it takes an enormous sum of money and time to get a new engine from a concept to commercial product. Look at how Honda have struggled in F1 with the new hybrid engines: that energy-recovery tech is going to be in road going cars within a decade or two, which is why Honda are keen on making it work in F1, but it's so hideously complicated to get the energy efficiency of an ICE up to state-of-the-art in F1 that even a company with a multi-billion dollar R&D division can't get it to work. For commercial cars we've long passed the point of an easy fix to clean up emissions so the next advances will be in energy-recovery systems. Thermoelectrics are still a long way off, unfortunately.

> Or us for our obsession with speed and power,

> driving two tonne vehicles with one person in it

> badly and at times unecessarily.

Most modern cars are significantly lighter than 2 tonnes. Most volume manufacturers don't advertise on the basis of power and speed anymore. And most people prioritise practicalities like boot space, fuel economy, road tax etc. over power and speed when buying a car.

[malumbu]

My point was it isn't simply a case of those dirty disel cars, and there are many reasons why we are in this position. I wasn't talking about totally redesigning engines, rather the control systems that help determine power, fuel efficiency and pollution. I expect that as more and more testing results come out, and the new standards are introduced, we will find out that some diesel cars are much cleaner than others. Now whether that is luck, the design of the engine and pollution reducing technology, or the way the engine is managed I don't know.

For heavy vehicles there had to be some more fundamental redesign to meet emissions standards, there again there tendes to be far more space in a truck or bus to fit a chemistry set.

Go back 25 years and many cars were much lighter and flimsier. Road safety standards changed making them heavier, and weitght has a big influence on fuel economy. Going back further as a young driver there were plenty of cars (virtually all petrol with decent fuel economy). And nobody wanted a diesel because they were agricultural in performance. (Yep the turbo also had a big effect). A quick Google shows that, for example, an estate car can exceed 1.5 tonnes and go up to a Range Rover and over two tonnes. OK we don't all drive Range Rovers but with the popularity of SUVs, and the 'I'll be more safer than you' weights are going up. The 1990 Citroen AX sports was like sh... off a shovel, weighing less than 800 kg so you'd come off pretty bad against a modern car. Crash impact systems leading up to autonomous cars could lead to considerable light-weighting but that is some way off.

I'm still not convinced there are government files warning that there would be mass adoption of diesel cars and that we'd all die. The state of knowledge until recent years was that fine particles were dangerous, and that these would be significantly reduced as technology was fitted. Which has happened - less and less is from diesel, and much you can't do a lot about blowing over from the continent. And as many have pointed out construction.

Nitrogen dioxide moved from an irritant to something more sinister in recent years. It was not hushed up, or a coup by the Grauniad/Greenpeace. Read the expert Committee papers eg www.gov.uk/government/publications/nitrogen-dioxide-health-effects-of-exposure

There has also been a number of select committee reports and it is a bit rich of Ed Davey to blame the Tories when his party were also in government.

Anyway simply trying to put a bit of balance/context into the argument. I'm a tree hugger but I simply don't buy into much of the popular views. And if you are going to get stuff delived, for the time being it will very likely to be a 'dirty diesel'

Here's something to help you save fuel - buses use it, but will it catch on for car drivers? http://www.bbc.co.uk/news/av/magazine-39792384/could-this-box-make-you-a-better-driver

[Cardelia]

I agree that, in the grand scheme of things, diesel is one small part of the whole air pollution issue. And I certainly don't think that the Government which promoted diesel had anything other than best intentions in mind. I suppose my point is that we should be careful about the unintended consequences of trying to change people's behaviour because we didn't *have* to go down the diesel route in the first place.

NOx is more than just NO2. There are many different oxides of nitrogen and they all have negative effects on the body. The physiological effects of NOx exposure (upper respiratory tract irritation, formation of nitrous/nitric acids etc. etc.) have been documented for absolutely ages. The issue has been trying to pin down how much of these negative health effects have been directly caused by NOx and not the other pollutants which are commonly found with NOx. Recent studies have helped in this regard, but the basic premise that NOx is actually quite nasty is not a new one.

[Tammy1987]

How do you think cars on diesel are more profitable?

[malumbu]

Nope they sell cars that will sell. Nice balanced post Cardelia. Nitrous oxide is not toxic in fact I understand that celbs take if for fun. For many giving birth its essential. It's a nasty greenhouse gas though.

I'm going to start a thread on consultation on the air quality plan, to bet a greater interet on this pretty important issue.