Diesel Emissions - MOT Test/Euro standards

[Ocko]

For lightweight diesel vans, weight 1760 Kgs to 3500 Kgs, (i.e. my 1999 VW T4, 2.5 TDi), Euro 2 standard specifies a particulates matter (PM) level of 0.20 gms per kilometre.

My recent MOT Emissions Test printed out the result as: "Mean Absorption Coefficient 0.9 l/min", (comfortably below the upper limit of 3.0 l/min).

My questions are:

1) What does "l/min" stand for?

2) Much more importantly, what is the relationship between the Mean Absorption Coefficient and PM? Ok, it MIGHT be a direct relationship and the PM could be 0.9/3.0 x 0.20. "MIGHT," is not good enough. Does anyone know for sure what the relationship is please? :

[Derek Uzzell]

"l/min" is plainly an abbreviation for "Litres per minute".

 

Can't help with your question about the exact relationship between the PM limit in gms per kilometre and the Absorption Coefficient figures produced during the MOT test. All I can suggest is you begin by immersing yourself in the lake of MOT test-related information held on the VOSA's website (www.vosa.gov.uk) and see if you can dredge up the answer there.

 

I did do some cursory searches on the VOSA site and there's plenty of stuff there about the MOT test emissions check, but I didn't look too hard (as long as my vehicles pass the test, I don't much care about the fine-detail mathematics behind the testing procedure) and I didn't quickly retrieve anything that would answer your inquiry. If you can't find the answer on the their website, you could always contact VOSA directly about it as I've found their staff very helpful when I've sought technical advice in the past.

 

Just out of curiosity, why is knowing about this relationship important to you, please?

[Ocko]

This is Ocko back again. Thanks to everyone who looked at my question. Sorry no one was able to help. In the meantime I have, with some effort, found the answers, which I give below. I could write a page of A4 but I doubt that would be appreciated so I will have to be relatively short and to the point. Besides, I don't have a computer and time at the library is scarce. You may not see me again for quite some time.

 

1) A Mean Absorption Coefficient of "0.9 1/m" means "0.9 per metre". (I did not mean to type "0.9 l/min". Also, my MOT printout prints the number "1" the same as the letter "l" and I hadn't picked this up). Some MOT printouts may print it as, 0.9 M-1, or more helpfully as, 0.9/m.

 

2) The test for Mean Absorption Coefficient is decades old and is a general test. It is NOT vehicle specific as the maximum value of 3.0/m is the same for most if not ALL commercial diesels! Hence it is not possible for me to relate the "0.9/m" to "grms per kilometre of particulates matter" as laid down in the Euro 2 standards for my VW T4. It clearly WOULD be possible for this to be done and there are moves under way by VOSA for it to be done, though not for all vehicles. This is where my page of A4 would begin so I'm signing off!

 

Why do I want to understand all this? For various reasons but primarily because I live in London and in October 2010 will fall foul of the Low Emission regulations......and it is my nature to want to understand things which affect me closely. Sometimes I want to understand things just for general knowledge. Cheerio.