Diesel particulate emissions

peasant

Here's some fodder for all you anti-dieslists out there

This is what it looks like when I hold my hand close to the exhaust of my diesel (1990 1.6 VW TD) , running cold on idle:



(engine is perfectly healthy btw ...this is just normal soot, no oil)

JHMEG

There's a startling amount of older diesel engines out there too.

Makes one wonder why they were able clean up the lead thing in petrol, but diesel still gets away with what it does. Policital lobbying in the EU by the euro car industry?

Esel

Wash yer hands!

mike65

Getting better, still I wouldn't worry the brain cancer from your phone will kill you first! :pac:

http://en.wikipedia.org/wiki/European_emission_standards

Mike.

peasant

JHMEG wrote: »

There's a startling amount of older diesel engines out there too.

Makes one wonder why they were able clean up the lead thing in petrol, but diesel still gets away with what it does. Policital lobbying in the EU by the euro car industry?

Actually, the current crop of high pressure, direct injection diesels are the worst when it comes to particulate emissions.

Sure, my old diesel is dirty. But what comes out the exhaust aren't particulates, those are lumps . Those lumps fall to the ground pretty quickly and should you breathe them in, you will cough them up again at some stage.

The soot from modern diesels is so small, that it stays suspended in the air for long periods and on breathing it in it will nest in your lungs.

Modern direct injection petrol engines are the first of their kind to even produce particulates

crosstownk

It would be nice to see a variety of pictures from owners of various diesel vehicles post the results here. A simple test is to put a tissue over the tail pipe for a few seconds and see what the condition of the tissue is afterwards.

JHMEG

peasant wrote: »

Actually, the current crop of high pressure, direct injection diesels are the worst when it comes to particulate emissions.

A lot of them also have filters which improve things, and the Euro 4 standards now are better - tho still pretty bad - than the no standards that were in place in 1991.

peasant wrote: »

Sure, my old diesel is dirty. But what comes out the exhaust aren't particulates, those are lumps . Those lumps fall to the ground pretty quickly and should you breathe them in, you will cough them up again at some stage.

I'd rather not have to rely solely on my lungs to reject them in a timely fashion (ie before the cancer starts).

peasant wrote: »

Modern direct injection petrol engines are the first of their kind to even produce particulates

This is true, which is why DI is flawed.

crosstownk wrote:

It would be nice to see a variety of pictures from owners of various diesel vehicles post the results here. A simple test is to put a tissue over the tail pipe for a few seconds and see what the condition of the tissue is afterwards.

I like the sound of that.

E92

peasant wrote: »

Modern direct injection petrol engines are the first of their kind to even produce particulates

Direct injection petrols are 54 years old, the first of the breed was the 300SL Gullwing.

They thus don't produce "new" pollution.

Unlike diesels which produce PM and loads of other gunk, DI petrols only produce PM when they are in ultra lean burn mode. When they are in high performance model they don't produce PM at all!

Diesels produce PM all the time, and as for NOx the modern DI petrols have a NOx cat so that keeps the extra NOx produced by the DI process at bay(besides the EU allows diesels to produce roughly 3 times more than petrols anyway). They thus are a much better choice than diesel for our health, and get much closer to diesel for CO2 than old fashioned indirect injection petrol engines, if not quite as good as old fashioned petrols on particulates.

JHMEG wrote: »

Anyone know of any Direct Injection petrol engines on the market now that meet Euro 5 requirements which come in next year?

I was reading an article that said that they won't meet Euro 5 because of NOx and (ironically for petrol) particulates. A quick look shows none of the VW or BMW engines currently out there are Euro 5.

Audi's new 3.0 TFSI and the all new 7 series, which is making its world debut on Monday week will meet Euro 5, and thus will be the first of many DI petrols to meet Euro 5. Audi publicly confirmed that the new 3.0 TFSI is a Euro 5 engine last week.

peasant

E92 wrote: »

Direct injection petrols are 54 years old, the first of the breed was the 300SL Gullwing.

They thus don't produce "new" pollution.

Sorry, but that is just wrong. You're confusing direct and indirect injection.

The petrol injection on the Gullwing and subsequent cars injects fuel into the air streaming into the engine somewhere along the air intake




Direct injection goes straight into the cylinder and is a very recent development on mainstream cars

E92

This page begs to differ;)!

"The 1955 Mercedes-Benz 300SL, the first sports car to use fuel injection, used direct injection."

peasant

That may very well be correct, but in the grand scheme of things, direct petrol injection on mainstream cars is a very new thing.

Diesel direct injection is somehwat older (especially on heavy machinery) but once again, it has only become mainstream on cars for about 10 - 15 years

JHMEG

E92 wrote: »

Audi's new 3.0 TFSI and the all new 7 series, which is making its world debut on Monday week will meet Euro 5, and thus will be the first of many DI petrols to meet Euro 5. Audi publicly confirmed that the new 3.0 TFSI is a Euro 5 engine last week.

My my, that's from an old post. I see that all new Accords, petrol and diesel, are Euro V, tho Honda don't use DI on petrol engines.

Without being pedantic, peasant is essentially correct. We didn't have particulate matter from petrols before DI, and we do now. That's not a good thing.

Matt Simis

crosstownk wrote: »

It would be nice to see a variety of pictures from owners of various diesel vehicles post the results here. A simple test is to put a tissue over the tail pipe for a few seconds and see what the condition of the tissue is afterwards.

Cold startup or running for a while?

Steve

Sort of on the same theme - saw a new (was either a passat or A4 or something, can't remember) diesel car, only a month or two old with what looked like a white 'soot' in the exhaust pipe....

Anyone any clue what this is?

Matt Simis

stevec wrote: »

Sort of on the same theme - saw a new (was either a passat or A4 or something, can't remember) diesel car, only a month or two old with what looked like a white 'soot' in the exhaust pipe....

Anyone any clue what this is?

BioDiesel emits white smoke when cold starting. Did it smell funny?

Steve

Matt Simis wrote: »

BioDiesel emits white smoke when cold starting. Did it smell funny?

It was parked when I saw it so don't know.

crosstownk

Matt Simis wrote: »

Cold startup or running for a while?

Personally, I'd go for the test at normal operating temperature (+80°C). Essentially it doesn't matter once all tests meet the same criteria - say 10 seconds at idle on a heated engine.

We all like our cars, but whatever will the neighbours think when the see car owners taking tissues to the tail pipe

E92

One of the more interesting things about the Wikpedia article is that even with the latest Euro 5 standards, diesel is still allowed to pollute 3 times more NOx than petrol. Though why petrol is allowed to produce twice as much CO as diesel is also a good question in itself.

What is also quite amazing is that there appears to be no difference between Euro 5 and Euro 6 for petrols, which Euro 6 diesels will still be allowed to pollute 33% more NOx than petrol(nevertheless it is a big improvement on present regulations).

peasant

E92 wrote: »

One of the more interesting things about the Wikpedia article is that even with the latest Euro 5 standards, diesel is still allowed to pollute 3 times more NOx than petrol. Though why petrol is allowed to produce twice as much CO as diesel is also a good question in itself.

I'm not good in chemistry, but it probably has something to do with the different properties of petrol and diesel.

Just soak a rag in petrol and one in diesl and then light them...the one with petrol will go whooosh and disappear into one big fireball and the one with diesel will splutter and smoke for ages.

Just because you're burning them in an engine doesn't make petrol and diesel the same all of a sudden.

JHMEG

peasant wrote: »

I'm not good in chemistry, but it probably has something to do with the different properties of petrol and diesel.

Just soak a rag in petrol and one in diesl and then light them...the one with petrol will go whooosh and disappear into one big fireball and the one with diesel will splutter and smoke for ages.

Just because you're burning them in an engine doesn't make petrol and diesel the same all of a sudden.

I think E92's (valid) point is that it's curious in Europe that there is a difference. In the US and Japan the standards are applied equally, and hence the sale of diesel vehicles is even banned in some parts.

E92

JHMEG wrote: »

I think E92's (valid) point is that it's curious in Europe that there is a difference. In the US and Japan the standards are applied equally, and hence the sale of diesel vehicles is even banned in some parts.

Exactly the point I wanted to make. Why can't both fuels by of the same standard? I would be in favour of them having the lower limits of each fuel naturally.

The valid concerns about PM from direct injection petrols can be very simply solved by the widespread usage of ultra low sulphur petrol, which cuts down on them significantly. ULS petrol also reduces NOx from direct injection petrols, and better still allows them to be even more efficient too.

Matt Simis

crosstownk wrote: »

Personally, I'd go for the test at normal operating temperature (+80°C). Essentially it doesn't matter once all tests meet the same criteria - say 10 seconds at idle on a heated engine.

From left exhaust (left engine?) after running for 12min (80c):




The only marks are the black ring of the exhaust, as expected on a modern diesel you cant see the PM (at idle and low RPM anyhow), its sinisterly small.

JHMEG

Matt Simis wrote: »

From left exhaust (left engine?) after running for 12min (80c):


The only marks are the black ring of the exhaust, as expected on a modern diesel you cant see the PM (at idle and low RPM anyhow), its sinisterly small.

If someone had blipped the throttle is it fair to say the tissue would be black?

crosstownk

JHMEG wrote: »

If someone had blipped the throttle is it fair to say the tissue would be black?

Maybe - but you'd be surprised how clean modern diesels are. Maybe 10secs at 2000s-1 might produce more of a result. Still, it's a damn sight cleaner than than peasant's original pic (granted peasant's was done at cold).

peasant

If I run my old stinker at idle when warm, there will be no soot either, nor will there be at 2000 rpm.

If however somebody were to hang out the back to collect a sample while I was driving up a hill at full turbo boost, they wouldn't need a tissue, but a bucket

(that also applies to new diesles by the way ..all diesels smoke under full load. Only a new diesel will produce particulates ...mine will throw with lumps of coal )

Steve

peasant wrote: »

...mine will throw with lumps of coal

Is that classed as renewable energy then?

peasant

stevec wrote: »

Is that classed as renewable energy then?

hmmm ..maybe I SHOULD tie a bucket to the exhaust ?

Steve

peasant wrote: »

hmmm ..maybe I SHOULD tie a bucket to the exhaust ?

efficientdynamics eat yer heart out....

Matt Simis

JHMEG wrote: »

If someone had blipped the throttle is it fair to say the tissue would be black?

I can try it tomorrow, but as above replies, most likely no. Certainly far from black anyway. Im not surprised you thought it would. :rolleyes:

Mine only puts out a bit of smoke after it was remapped and when absolutely flooring it on fossil diesel. The version with DPF doesnt like Bio much but limits the PM output. Black smoke is a sign of unburnt fuel, I never saw it pre-remap.

Matt Simis

crosstownk wrote: »

Maybe - but you'd be surprised how clean modern diesels are. Maybe 10secs at 2000s-1 might produce more of a result. Still, it's a damn sight cleaner than than peasant's original pic (granted peasant's was done at cold).

I might run the allroads 2.7T petrol engine at 4000RPM (ballpark similar to a diesel at 2000rpm) for 10sec and compare.

JHMEG

Matt Simis wrote: »

I can try it tomorrow, but as above replies, most likely no. Certainly far from black anyway. Im not surprised you thought it would. :rolleyes:

I'm surprised you think it would be clean, based on replies like this:

"If however somebody were to hang out the back to collect a sample while I was driving up a hill at full turbo boost, they wouldn't need a tissue, but a bucket"

I've yet to see a diesel that doesn't put out plumes of smoke on WOT, and letting off WOT, as per the above replies.

Matt Simis wrote: »

I might run the allroads 2.7T petrol engine at 4000RPM

I did it already on the VTI, and got someone to rev the stones out if it while I did it. Nothing.

Matt Simis

JHMEG wrote: »

I'm surprised you think it would be clean, based on replies like this:

"If however somebody were to hang out the back to collect a sample while I was driving up a hill at full turbo boost, they wouldn't need a tissue, but a bucket"

I've yet to see a diesel that doesn't put out plumes of smoke on WOT, and letting off WOT, as per the above replies.

Lol.

- I never said clean, I said not black.
- You dont know what WOT means or you think diesels redline at 2k rpm
- The replies, if you read them, said under load (driving) + WOT + uphill = smoke. More smoke from older cars.

JHMEG

Matt Simis wrote: »

The replies, if you read them, said under load (driving) + WOT + uphill = smoke. More smoke from older cars.

One reply actually said that. The rest is based on my experience of seeing diesels in action. Old or new.

WOT applies to petrols. You can be pedantic about it, but you know what I mean, I think. Otoh, WOT has nothing to do with redlines... do you know what WOT means?

Matt Simis

JHMEG wrote: »

One reply actually said that. The rest is based on my experience of seeing diesels in action. Old or new.

WOT applies to petrols. You can be pedantic about it, but you know what I mean, I think. Otoh, WOT has nothing to do with redlines... do you know what WOT means?

It isnt as mysterious as you like to allude.
"In the case of an automobile, WOT is when the accelerator is depressed fully."
http://en.wikipedia.org/wiki/Wide_Open_Throttle

To get to and hold 2krpm, one wouldnt depress the accelerator fully now would you.

I tried the 2k rpm + tissue test stationary, there was absolutely zero visable soot on the tissue or coming from the exhaust. I could only hold it about 4seconds (due to exhaust heat burning my hands) as there is only so much personal injury Ill tolerate for the sake of argument.

peasant

To be fair to modern diesels now ...my yoke is purely mechanical. No clever sensors and computer programmes to optimise everything, more turbo boost means more fuel, regardless if it's actually needed or not.
So, modern diesels are a lot more efficient plus most of them do have filters.

JHMEG

Matt Simis wrote: »

It isnt as mysterious as you like to allude.
"In the case of an automobile, WOT is when the accelerator is depressed fully."
http://en.wikipedia.org/wiki/Wide_Open_Throttle

To get to and hold 2krpm, one wouldnt depress the accelerator fully now would you.

I tried the 2k rpm + tissue test stationary, there was absolutely zero visable soot on the tissue or coming from the exhaust. I could only hold it about 4seconds (due to exhaust heat burning my hands) as there is only so much personal injury Ill tolerate for the sake of argument.

WOT = wide open throttle, often taken to mean foot to the floor, but it literally means the throttle is wide open. BUT, petrol engines have throttles, diesel engines don't. It's not clear from your posts whether you know that or not about diesels, tho I suspect not.

Of course one wouldn't depress the accelerator fully to maintain an engine speed of 2000 rpm in normal circumstances. However one can depress the acceleator fully in a high enough gear and achieve "WOT" at 2000 rpm, and depending on the load and gear even maintain it.

Now, that's me done with this thread. It's turning into a silly game of semantics.