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Volkswagen emissions scandal

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Volkswagen emissions scandal

AndyRKett said:
Next time you're sitting in traffic take a look at the exhaust pipes of cars especially ones that are less than 3-4 years old. I've been doing this a lot recently, because of people making claims about what comes out of Diesel engines.

If you look without an element of bias you'll start to notice more often than not petrol cars have very dirty tail pipes with oil and unburnt petrol. Where as diesel tail pipes tend to be cleaner and dryer.

I'm not looking to start an argument or debate over this. Spend a few weeks doing this and see how it goes.
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Much as I hate to agree...

Comparison of the Mazda and Euro 6 diesel DS3 tail pipes bears this out. Although what you see in a tail pipe is the larger particulate matter, the smaller really damaging ones aren't as visible to the naked eye. A car with a particulate filter will have less visible particulates but when it's regenerating or burning off the captured particulates the smaller invisible matter coming out the exhaust is as bad for your health as the full on diesel smoke.
 
ChrisUK said:
Do you not watch top gear? Season 15 Episode 2. They bought an old M3, Merc and A Ford Saphire Cosworth. They put them through the German MOT test with horrifying results.

They even test brake fluid boiling point...
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Oh yeah, I remember now, lol! If memory serves correctly, only the Sierra passed?
 
pooroldcodger said:
I do agree with you. Many cars aren't serviced at all or at least not fully, so this can have all sorts of effects. Also a petrol car that either isn't running cleanly, or does lots of short journeys will have a sooty tail pipe. I used to love the look of my petrol engine exhaust pipe after a good long motorway run - dry and grey, but not too white, and definitely not sooty.(sad I know!)
I have a feeling though (without any scientific evidence I will add) that I think a modern diesel exhaust may look cleaner to the eye, but if the particulates that are still coming out are visible, or invisible, and more or less of a health hazard than petrol fumes - I don't know, but my chest seems to know the difference.
I will add though that I can be sat behind a car in traffic, and even with all windows closed I can tell immediately if somebody lights up a cig because I start to cough, so I know I am sensitive.
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The blackened tailpipe on modern petrols is normal. The grey we used to see was actually caused by the lead in the fuel. Since unleaded fuel and catalysts, black is what we should get.

Any petrol car running badly to cause emission issues will light its warning light and fail any MOT test. Old petrol engines with working catalysts will produce close to the same emissions as when new. I've seen this on engines with over 100,000 miles on them. Conversely, diesels emissions are not tested with a gas analyser, just a visual check. As they age, the injectors wear and combustion is less efficient, producing more pollutants. Compare sitting behind a new diesel and one just a few years old. Whereas an old petrol stays the same.
 
As time has gone on advances have brought un filtered petrol exhaust closer to filtered diesel in terms of particulates. Which is a shame as I'm still to drive a diesel that wouldn't be improved by a decent engine..

1st you have a lot of petrol turbos out there, far more than before when setting one up slightly rich (little soot at full throttle) is infinitely preferable to slightly lean (mmm melted pistons).

2nd Direct injection engines burn the fuel more completely so more PM out of the tail pipe.

3rd there's been no PM target for petrol engines so they never bothered attempting to reduce it.

However good news is you can redesign the combustion chambers to reduce it or fit a PPF which due to the higher exhaust gas temps of a petrol should Regen easily and therefore not be an expensive liability and require adblue..
 
ChrisUK said:
Direct injection is a nightmare for maintenance, Look at all the VW horrors with carbon build up on valve seats. It's so rife there's specialists that will come to your door and do a clean.
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Yup a mate recently bought a petrol 3 series...needs a walnut blast obviously as its currently running like a bag of crap.

It doesn't have to be unreliable Toyota fitted an additional injector in the inlet tract which stops all the inlet coking,
 
The carbon build up is most likely due to the amount of EGR.

A good few years ago Audi did tests to show their new EGR was taking about 50- 100 k off the expected life of their TDI engines.

To meet the tighter regs they were putting more exhaust gasses back through the system and therefore introducing crap back into the combustion chamber and causing the build up.
 
hennabm said:
The carbon build up is most likely due to the amount of EGR.

A good few years ago Audi did tests to show their new EGR was taking about 50- 100 k off the expected life of their TDI engines.

To meet the tighter regs they were putting more exhaust gasses back through the system and therefore introducing crap back into the combustion chamber and causing the build up.
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Egr is one of the causes of carbon build up but it's not the only reason why certain (predominantly BMW and VW although also PSA cars that share engines) DI cars suffer with issues.

On a port injected car although EGR gases do travel through the inlet valves they pass through along with air and petrol. Petrol being a solvent cleans the valves on the way through. On a DI car the fuel doesn't touch the inlet valves so any crap stays there. The options are cleaning up the inlet gases before they hit the valves, fitting the additional injectors to rinse the valves with fuel occasionally (as previously mentioned Toyota does this) or do nothing and let your customers pay to have their valves cleaned every 2-4 years depending on usage.
 
Also worth considering AdBlue equipped cars, the heavy goods industry has been playing with this for years and are finding its the only economic way to meet future 'EURO' standards.
 
portland_bill said:
Some thoughts.

If the cars do not comply with the emission standards required when sold, could they therefore be illegal to be on the road. This would require VW either to modify them to meet the standards, which may be difficult, or they would have met them already, or they could be forced to buy them back. Perhaps replace with new ones that do meet the standards.

The authorities could leave the cars on the road, but re-assess the taxation on them. So if any UK cars are affected, they may suddenly have their tax hiked, making them expensive. Could be a few cheap used one around shortly.

The car manufacturers do not generally make their own injection systems. For VW, the injectors and pump, etc., are probably Bosch. So don't Bosch have a big hand in the way the ECU is programmed? And don't they also provide such products and services to a lot of other manufacturers. If between VW and Bosch they can't actually manufacture an engine that is clean enough, how can anyone else? Do the others really know something VW don't? Or could this affect nearly every recent diesel car?

If Bosch knew about this, have they provided the same "defeat" service to others.

For years now diesel owners have been proudly stating that "newer diesels are so much cleaner". Perhaps not? Oops!
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Bosch maybe the injector parts supplier, but they made everything the way VW wanted.
Remember Bosch also supplies parts for the Alfa ( Fiat) JTD engines, which uses a complete different ( and cleaner) system.
VW (and Merc. and BMW) didn't want to pay Fiat for using their JTD components, instead they hung on to old, outdated systems they modified at their own views, with known results.....
 
My 2.0 tdi euro 6 is not part of the scandal so not subject to any recall or work but manages to meet emotions targets without adblue, it seems to be mostly bigger cars which need it
 
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