Car emissions

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Car emissions

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Treacodactyl
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Joined: 28 Oct 2004
Posts: 25795
Location: Jumping on the bandwagon of opportunism

Posted: Fri Jul 08, 05 8:03 pm Post subject: Car emissions
My car has just passed it's MOT which was a little unexpected as she's getting to the age where major things start to go wrong. The emissions are getting a little worse each year but I have no idea what they should be. Does anyone know where I can check the legal limits for CO2 & hydro carbons for a petrol car?

Jonnyboy

Joined: 29 Oct 2004
Posts: 23956
Location: under some rain.

Posted: Fri Jul 08, 05 11:47 pm Post subject:
You should get a report with the MOT cert which details your cars emissions and the legal requirement. The testing machine should spew out a hard copy. Ask the garage which carried out the MOT for it.

dougal

Joined: 15 Jan 2005
Posts: 7184
Location: South Kent

Posted: Sat Jul 09, 05 12:40 am Post subject: Re: Car emissions

Treacodactyl wrote:

..Does anyone know where I can check the legal limits for CO2 & hydro carbons for a petrol car?

You could have a read of
https://www.motuk.co.uk/manual_730.htm
However, I think a large part of the answer may be 'the Department of Transport Emissions book ... "In-Service Exhaust Emission Standards for Road Vehicles".'
There are all sorts of different standards, and which one applies depends on the vehicle. I think some of the limits are actually set by the manufacturer on a per-vehicle-model basis.
And, yes, that does seem a little unfair, in that an imperfect example of a "good" vehicle could fail, while an ordinary "stinker" would pass...
I think the justification is that its about vehicles being maintained in a good state of repair, rather than getting cleaner vehicles *onto* the road...

Treacodactyl
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Joined: 28 Oct 2004
Posts: 25795
Location: Jumping on the bandwagon of opportunism

Posted: Sat Jul 09, 05 7:28 am Post subject:

Jonnyboy wrote:

You should get a report with the MOT cert which details your cars emissions and the legal requirement. The testing machine should spew out a hard copy. Ask the garage which carried out the MOT for it.

I have and I've also got all the old ones so I can see that the emissions are getting slightly worse. I get the ammounts but all the printout says is 'pass'. Now I have no idea if a 0.12% CO2 reading is good or bad, if the limit is 0.2% I may have a problem next time, if it's 5% then the car is running very well.

Thanks for the link dougal, but there doesn't seem to be any limits mentioned.

alison
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Joined: 29 Oct 2004
Posts: 12918
Location: North Devon

Posted: Sat Jul 09, 05 8:12 am Post subject:
I assume all testing machines aren't equal. Our car, now 9 years old always failed on emmissions when it first had an mot, but now we have moved it has passed everytime.

nora

Joined: 20 Mar 2005
Posts: 1539
Location: West Yorkshire

Posted: Sat Jul 09, 05 8:18 am Post subject:
I have an old diesel renault which struggles on emissions at MOT time. I've found that if you pour a bottle of Anti-smoke solution in the fuel tank a week before the MOT and drive about 100 miles, it then passes. cost about �8.

dougal

Joined: 15 Jan 2005
Posts: 7184
Location: South Kent

Posted: Sat Jul 09, 05 12:42 pm Post subject:

Treacodactyl wrote:

... all the printout says is 'pass'. Now I have no idea if a 0.12% CO2 reading is good or bad, if the limit is 0.2% I may have a problem next time, if it's 5% then the car is running very well.
Thanks for the link dougal, but there doesn't seem to be any limits mentioned.

1/ There is NO limit for CO*2*. There is a limit for Carbon *Monoxide* CO. Or rather, lots of limits.

dougal wrote:

There are all sorts of different standards, and which one applies depends on the vehicle. I think some of the limits are actually set by the manufacturer on a per-vehicle-model basis.

2/ The page linked explains that there are different procedures for petrol and diesel engines, and those with and without catalysts. It explains which limit to apply if the vehicle and engine are different ages. And that there is *one* limit for all vehicles older than 1995 - unless it can be proved that the vehicle *never* could meet that standard (see the para at top right, headed Personal Imports). The limit for pre-1995 petrol engines (no cat) is 3.5% CO and 200ppm unburnt hydrocarbons. (The illustrative figures for catalyst-equipped vehicles are *much* lower.)
But the clear message of that page is that there is a whole *bookful* specifying the limits for particular models.

dougal wrote:

...the answer may be 'the Department of Transport Emissions book ... "In-Service Exhaust Emission Standards for Road Vehicles".'

This 130 page *book* does not seem to be web-accessible or downloadable.
But you can pre-order the August 2005 edition on Amazon.

3/ I discovered this link to a consultation paper about 2004 changes. The abstract reads:

Quote:

In-use emissions requirements are enforced at annual MoT test and roadside checks. In accordance with European Directive 96/96/EC, emissions requirements are based on information provided by manufacturers, where available, and are model specific.

Like I said:

dougal wrote:

There are all sorts of different standards, and which one applies depends on the vehicle. I think some of the limits are actually set by the manufacturer on a per-vehicle-model basis.

I'm sorry I wasn't clear enough previously -
You need to look up your *exact* vehicle in the current edition of the reference book to find the limit to apply for *that* vehicle.

dougal

Joined: 15 Jan 2005
Posts: 7184
Location: South Kent

Posted: Sat Jul 09, 05 12:53 pm Post subject:

nora wrote:

I have an old diesel renault which struggles on emissions at MOT time. I've found that if you pour a bottle of Anti-smoke solution in the fuel tank a week before the MOT and drive about 100 miles, it then passes. cost about �8.

You can reduce your diesel's measured *and* everyday CO and particulate emissions by running on biodiesel...
Even at 5%, there's an improvement.

Treacodactyl
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Joined: 28 Oct 2004
Posts: 25795
Location: Jumping on the bandwagon of opportunism

Posted: Sat Jul 09, 05 6:31 pm Post subject:

dougal wrote:

1/ There is NO limit for CO*2*. There is a limit for Carbon *Monoxide* CO. Or rather, lots of limits.

dougal wrote:

There are all sorts of different standards, and which one applies depends on the vehicle. I think some of the limits are actually set by the manufacturer on a per-vehicle-model basis.

Good point, well made and of course correct; it does say CO.

I did understand the comments about each car having it's own limits but I just wondered if there was a rough guide for common engines. Mine's a 1.6i 16v 1995 with a cat which is quite a common engine.

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