MoT test instruments: how accurate are they?

Last MOT our Opacity measurement was 0.1 iirc (can't remember the units), he double checked to make sure the probe was in the exhaust!.

All standard, one of the cleanest cars he'd had on the exhaust tester apparently.

My tester had a similar issue, from memory he got 0.22 the first year and didn't believe it. He has had to become used to my engines low figures over the years :) I gave it a full and very thorough service, just after buying it, as I always do when buying a new to me vehicle.
 
Sponsored Links
I didn't suggest 'burning', rather the waste heat in the cylinder turning the water mist into steam - operating rather like a steam engine. Water mist goes in the cylinder, turns to steam, the steam helps push the piston down as it expands.

I don't think it works like that. Heat in the cylinder isn't "waste" heat. It's waste heat once it goes out of the exhaust valve. Any energy that goes into evaporating the water into steam in the cylinder, can only come FROM the contents of the cylinder, so what you gain by expanding the water into steam, would have to come from the burning mixture in the cylinder.
 
I'm not sure the figures are that far different? The current EU 6 carbon monoxide limits for petrol are 1.0 g/km and for diesels. 0.5 g/km, so that's only a factor of 2. For HC, it's harder to measure because diesels get to add HC and NOx together, but broadly, they're about the same at 0.1 g/km.




No, I'm cool (if you'll excuse the pun!) with that. The gas coming in through the EGR valve will never be hotter than what's in the combustion chamber. And, of course, any that goes into the cylinder will reduce the amount of oxygen available for combustion.
Here is a link, this is also why previous Governments believed diesel was such a miracle as far as emissions go. As far as the planet goes, they are much better but as far as local pollution goes, much worse unfortunately...
http://www.air-quality.org.uk/26.php
 
Sponsored Links
Here is a link, this is also why previous Governments believed diesel was such a miracle as far as emissions go. As far as the planet goes, they are much better but as far as local pollution goes, much worse unfortunately...
http://www.air-quality.org.uk/26.php
When was that written? I'd guess at mid '90s? And yes, it's certainly true that government policy incentivised diesel when "global warming" was public enemy No.1. However, in doing so, we created a massive air quality problem which we're now trying to fix. That said, for the last few years, after falling for over a decade, average CO2 emissions from the UK vehicle fleet is on the rise again, as people turn their backs on diesels in favour of petrol again.
 
2013 Mk2 Kuga 2l Diesel (Euro 5 I believe?).

Sounds about right. Your registration document might tell you in the field called "Euro status No." However, 2013 was certainly Euro 5 territory. It's hard to know, because there are all sorts of skullduggeries that manufacturers can get up to in order to give themselves more time to comply!

Anyway, if it is EU5, it will have a DPF, so it should be completely free of visible smoke. A few years ago, I did some type approval emissions tests on a few different cars, and the diesels were better on particulates than the petrols!
 
When was that written? I'd guess at mid '90s? And yes, it's certainly true that government policy incentivised diesel when "global warming" was public enemy No.1. However, in doing so, we created a massive air quality problem which we're now trying to fix. That said, for the last few years, after falling for over a decade, average CO2 emissions from the UK vehicle fleet is on the rise again, as people turn their backs on diesels in favour of petrol again.
Looks like the article gained more content over a long period of time at a guess? I think the way they are trying to keep petrol engines as CO2 friendly as diesels is by downsizing them as well as strapping on electric motors to help them accelerate . It's very common for sub 1 litre engines in Mondeo sized cars. The simple reality is though, getting us to keep our cars for longer would be by far the single most effective way to reduce Global emission because the Lions share of CO2 is pumped out building the thing in the first place. I wonder too if anybody considered the emissions produced by manufacturing emissions devices? Johnson Mathey near where I live pumps out some noxious smelling smoke from their plant making DPFs and I'd guess making synthetic urea and plastic containers for it probably does the same...
 
Sounds about right. Your registration document might tell you in the field called "Euro status No." However, 2013 was certainly Euro 5 territory. It's hard to know, because there are all sorts of skullduggeries that manufacturers can get up to in order to give themselves more time to comply!

Anyway, if it is EU5, it will have a DPF, so it should be completely free of visible smoke. A few years ago, I did some type approval emissions tests on a few different cars, and the diesels were better on particulates than the petrols!
Isn't it the case now that the tyres produce more particulates by wearing on the road than the engines do?
 
Exactly.....maybe it's time to stop caning diesels.
John :)

Too late for that the ICE has been, largely consigned to the history books. TBF probably about time, it's had a good run for it's money. Still I'll miss the wuffle of a V8
 
Last edited by a moderator:
In years to come, our grandchildren are going to look back on the ICE and rank it along with the horse and cart and steam engines.
 
Sponsored Links
Back
Top