Thread: WoW: supermini class diesel cars produce more NOx than a 40 tonne truck!

... Agreed. he was only drawing an over-all comparison between his newer XYZ Euro-6 bus and the one he'd just "retired"...

One must allow a certain Literary License to the proud owner of a New Toy...

Or maybe he believed everything the Salesman had told him !

In Real Life... My old HX/Z Holden V8 with all the anti-pollution garbage on it, was supposedly cleaner than the earlier HJ V8s... But used more fuel and 'servicing' to travel the same distance.
One can only wonder just how worthwhile was the net gain in cleanliness.

Originally Posted by DiscoMick

It certainly shows that manufacturers have been avoiding the rules on emissions once their vehicles are out in the real world. I guess there will have to be random testing of vehicles in real-world driving before they are approved for sale.

No. The rules specify exactly the conditions under which the emissions limit must be met, but says nothing about all the other conditions the vehicle may operate in. The manufacturers are guilty only of designing engines to meet the specified tests. (Note - this is not the same as changing engine settings when test conditions are detected, as VW did.)

This is the same sort of approach as used, for example, by racing yacht designers designing to meet the rules, or Formula 1 racing cars designing cars to meet the rules. If the emission testing rules do not reflect real life, you can hardly lay the blame at the feet of the manufacturers or designers.

And the problem with "real world" testing is - which real world? London, with stop/start traffic, short distances, high humidity, low temperatures? Houston, with mostly long distance freeway driving, high humidity, high temperatures? Outback NT, with very high temperatures, very high speeds for long periods, low humidity? Singapore, with stop/start traffic, high humidity, high temperatures, very short distances? Sweden, with long distances, relatively low speeds, very low temperatures?

John

But John
Irrespective of rules/ testing regimes etc etc
-Trucks in the real world are producing Nitrous Oxides at less than 0.08g/km
-Surely a buzz box can too?

10L truck engine moving 40T makes less NOx than a 1L car engine moving 1T

It doesnt matter about testing regimes city air pollution (smog) IS correlated with NOx emissions and small cars are pumping it out?

Irrespective of testing regimes - why is it that a current euro6 small car doesn't meet euro1 standards EXCEPT for in a specified test regime?

I don't live in a city - smog is not a huge concern in Cooktown but sitting back looking in on this saga there will have to be big changes. Either stocks in Urea will skyrocket or diesel small engine production will plummet - not too many other options available!

The electric car brigade will be getting a boost from this too!

s

Originally Posted by JDNSW

I suspect that the test conditions do not even come close to the real world, and that trucks and buses do better than small cars because the engines operate close o maximum power most of the time, whereas a car engine rarely operates at more than about 10% of maximum power.

John

John,please don't denigrate this thread with facts. Pat

Originally Posted by DiscoMick

It certainly shows that manufacturers have been avoiding the rules on emissions once their vehicles are out in the real world. I guess there will have to be random testing of vehicles in real-world driving before they are approved for sale.

There has been Mick,show room stock vehicles were tested in the UK and VW's were the cleanest,Mazda the dirtiest. Pat

why are petrol engine not having the same issues? or ore they?

Originally Posted by roverrescue

But John
Irrespective of rules/ testing regimes etc etc
-Trucks in the real world are producing Nitrous Oxides at less than 0.08g/km
-Surely a buzz box can too?

10L truck engine moving 40T makes less NOx than a 1L car engine moving 1T

It doesnt matter about testing regimes city air pollution (smog) IS correlated with NOx emissions and small cars are pumping it out?

Irrespective of testing regimes - why is it that a current euro6 small car doesn't meet euro1 standards EXCEPT for in a specified test regime?

I don't live in a city - smog is not a huge concern in Cooktown but sitting back looking in on this saga there will have to be big changes. Either stocks in Urea will skyrocket or diesel small engine production will plummet - not too many other options available!

The electric car brigade will be getting a boost from this too!

s

Trucks will always run more efficiently than cars,the reason is simply because they run at their operating temp 95% of the time,a small privately owned vehicle runs at it's operating temperature maybe 10% of the time.Truck manufacturers spend millions making gains in efficiency because it saves the operators money,a 5% saving in fuel over 12 months per truck across a fleet makes a huge difference to the bottom line which then sells more trucks,manufacturers are happy because they get a return on their R&D costs and the owners get a return on fuel,everyone's happy.Private car sales are the opposite,if you had two vehicles,one was really clean burning for 30K and the second not quite as clean for 25K which do you think people will buy?. Pat

From what I have read - trucks meet euro6 because they use urea injection.

Eevo, petrol engines don't generate Nitrous Oxides in the quantities of diesel engines
I am under the understanding that NOx creation from petroleum combustion is favoured by increased burn temperatures and leaner burn conditions.
Petrol runs Stoichiometric ratios nearly all the time, Diesels run lean nearly all the time.

It is a known fact that city fog is directly correlated to NOx

s