How effective is air recirculation for blocking out pollution?

ahfh1

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Hi,

Here's the scenario: You are driving along and get stuck behind a bus, which is just about to move away from a bus stop. All of a sudden a cloud of black smelly exhaust fumes as the bus accelerates engulfs your car and the pollution enters your car cabin. I'm sure this has happened to us many a time!

What do you normally do to counteract the horrible fumes?

Usually as soon as I see any black smoke from the bus in front, I'll immediately hit the air recirculation button to recirculate the existing clean air in my cabin. The theory is that it will also close off the vents to prevent outside (bus fumes air) from entering the cabin. However, sometimes I may not hit the air recirculation button in time!

Or is it better to leave the air recirculation off, and bear with the bus fumes entering your car cabin, in the knowledge that fresh outside air (once you have overtaken the bus) will replace the inside air?
 

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I have used air recirculation when I've been going through a reasonable length tunnel and it has stopped the general exhaust fumes from entering the car. I always switch it back to normal as soon as I come out of the tunnel. As this situation has occurred mostly when I have been on holiday in Austria and Switzerland my assistant (my wife) in the passenger seat usually does this for me!!
 
Also, shouldn't this happen automatically when you have auto recirc set?
 
I don't think it displays or lights up anything, it just gets on with it in the background.

I've certainly not breathed in any smelly fumes since switching it on, and driving through diesel clouds etc.
 
I find the most effective way is to turn off the climate control.

The recirc button seems to still let the smell in!
 
Except a EURO 6 diesel that produces far less of them and much less CO2 than a petrol engine and goes much further on every litre. The problem is with older, especially buses and lorries, where there engines are not up to modern standards. Lets ban all Buses and lorries and then we would not get stuck behind them....

Lets not start a silly Petrol vs Diesel thread, please!
 
Except a EURO 6 diesel that produces far less of them and much less CO2 than a petrol engine and goes much further on every litre. The problem is with older, especially buses and lorries, where there engines are not up to modern standards. Lets ban all Buses and lorries and then we would not get stuck behind them....

Lets not start a silly Petrol vs Diesel thread, please!

Some one did........................................see above?
 
I don't think it displays or lights up anything, it just gets on with it in the background.

I've certainly not breathed in any smelly fumes since switching it on, and driving through diesel clouds etc.

Wish it told you when it's doing something, I was stuck behind a dying car the other day and the fumes / smoke was immense.
 
Except a EURO 6 diesel that produces far less of them and much less CO2 than a petrol engine and goes much further on every litre. The problem is with older, especially buses and lorries, where there engines are not up to modern standards. Lets ban all Buses and lorries and then we would not get stuck behind them....

Lets not start a silly Petrol vs Diesel thread, please!

hmmmm I think you need to tell yourself that before typing then
 
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Wish it told you when it's doing something, I was stuck behind a dying car the other day and the fumes / smoke was immense.

I agree - mine is switched on, but I was following a ratty old 2-stroke scooter on the way home from work last night and it filled the car with fumes and I couldn't tell if the recirc was doing anything.

it certainly didn't seem to be doing much...
 
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I agree - mine is switched on, but I was following a ratty old 2-stroke scooter on the way home from work last night and it filled the car with fumes and I couldn't tell if the recirc was doing anything.

it certainly didn't seem to be doing much...

Saying that though I've never noticed any outside smells in the car. It's just got new car smell
 
I've noticed your smells in the car, but been too polite to mention it ;)
 
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As the OP's post referred to buses, and buses produce most of the particulates in this county, along with some Taxi
I'm sure an activated charcoal pollen filter would ?

It certainly stops the exhaust fume smell.
Partculates can pass through solid objects as they are so minute, so whether any filter could stop them I don't know..
 
The problem is a lot of buses, especially around my area, are so old I doubt if any of their engines meet Euro1 standards let alone the current Euro 6 standard. The other silly thing is, that living in a fairly rural area, there are a lot of buses and coaches used to take children to school and these are generally even older than the normal buses.

If we were in Germany none of these buses would meet the 'Umwelt 4' standard and would therefore not be allowed to enter most town centres and would almost certainly have been scrapped years ago.
 
Partculates can pass through solid objects as they are so minute, so whether any filter could stop them I don't know..

If only someone could devise some kind of particulate filter for diesel? You could call it a diesel particulate filter or DPF for short.

Maybe I'll give Audi a call and suggest it...

</snark>
 
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I assume new buses and lorries as well as cars have to have a DPF to meet the current Euro 6 standard.
 
If only someone could devise some kind of particulate filter for diesel? You could call it a diesel particulate filter or DPF for short.

Maybe I'll give Audi a call and suggest it...

</snark>
I was responding to the post about activated charcoal pollen filters, however I wouldn't suggest a DPF as you'll have some of the diesel performance brigade, if there is such a thing, complaining about it will reduce the performance of their engines :D If mine has a activated charcoal pollen filter I don't consider it working very well as if I drive on roads that have been treated with grit and salt after it's been put down a few days before and nicely broken up I still get a taste of it inside the cabin.
 
I was responding to the post about activated charcoal pollen filters, however I wouldn't suggest a DPF as you'll have some of the diesel performance brigade, if there is such a thing, complaining about it will reduce the performance of their engines :D

This used to be a big think with some members. It was a bit like those who wanted to remove the catalytic converter from petrol engines to make go faster. Now with the current MOT a physical and emissions test has to be done to any diesel engine that is supposed to have a DPF to make sure the DPF is still there and working. It also makes the car illegal if the DPF is removed. So I suppose those companies that were making money out of removing the DPF will now be able to make more money by putting them back.

My current A3 has a DPF and still goes very well indeed!
 
I think under the mot checks the dpf one is only visual and as on many vehicles the dpf is inside the same 'bumb' as the convertor thus it cannot be seen anyway if it is removed, and unless a warning light is illuminated on the dash, which can easily be eliminated by a ecu map, then the tester really doesn't know if it is there or not. There are plenty of people out there who think dpf's are the devil's own work and a very expensive item to replace on higher mileage vehicles. Having owned a diesel with a dpf I know know that a diesel engined car is totally unsuitable because of the dpf even though I can see the benefits of having one...
 
This is a link to the Government statement about DPFs: https://www.gov.uk/government/news/new-rules-for-mot-to-test-for-diesel-particulate-filter

Personally I've owned five A3 diesel as well as four A3 petrol engined cars (all 1.8T). Four of my A3 diesels (1x140, 2x170 and now 1x184) that have been fitted with a DPF and I have never had any problems or even been aware that it is there. I have not even been aware of the re-gen of the DPF. Perhaps I drive 'spiritedly' enough for it never to show.

Is a DPF any more expensive to replace than a catalytic converter on a petrol engine. Not really a problem as far as I'm concerned as I will never own a high-mileage vehicle, petrol or diesel. The highest mileage I've had since I started keeping records in 1985 was with a Golf VR6 2.8 petrol at 60k. The highest with an A3 was a 1.8T petrol at 46k and the highest with a diesel was an A3 140cr with 38k.
 
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Unfortunately you probably have both, however catalytic convertors, or engines, tend not to fail prematurely under normal conditions and catalytic convertors tend to last on average about 100,000 miles under normal conditions, if not more and it is only recently that dpf's are reaching that mileage. It is failed regens, and I am not necessarily talking present audi's, that have caused numerous and costly issues with diesels since they've been around. There are many horror stories of engines being contaminated with diesel causing their untimely failure. Your link states what I was saying however the check can only be visual as there no change to the emisions from a diesel by removing the dpf. Thus on certain vehicles there isn't really anyway of asserting if it has been removed. Despite it being illegal, such as fitting hid kits into ordinary headlamps, there are still plenty of places advertising the removal of dpf's and quite legitimate companies as well that are recommended for Audi's.
Yes your style of driving is probably the best way, and the long journey's you make. However the very short journey's I was making, 5 miles max with the engine not really warmed up, wasn't long enough to generate a proper regen, thus I had to take the car once a month for a fast run as recommended. Rather a waste of diesel...