The Older Diesel

[Pebble]

In recent years I have become quite good at guessing the age of the vehicle that has passed (or at least its Euro Vehicle Emissions Standard). In particular the Euro4 pre DPF diesels that started to be ruled out after 2010. They smell so bad, so toxic. hate it when they pass on a hill

But back in 2008 when I took up cycling they didn't seem to smell, yes there would be the car or waggon belching out black smoke that was deeply unpleasant, but the new diesels at the time didn't seem to stink.

Is this because we have just become accustomed to cleaner air, in the same way I never once noticed the smell of cigarette smoke in pubs or trains or cafe's, now one person can sting out an open air park with a cigarette.

Or is it because these old diesels are tired and stink more ? but I think not, I have an old 08 plate non DPF van, and it stinks, but it has only done 70k, doesn't burn oil, gets 50+ to the gallon, I would say the engine is in good nick.

20years ago what were we breathing in

[Bmblbzzz]

Both of those?

(But did you really not notice the smell of cigarette smoke in pubs etc?)

[Bonefishblues]

The EGR systems are often coked up so don't function properly. Whoever thought up the wheeze that it was a good idea for an engine to eat its own exhaust didn't give any thought to its maintenance.

[Pebble]

(But did you really not notice the smell of cigarette smoke in pubs etc?)

yes sometimes when it was bad and extra thick, and certainly in restaurants etc when eating (esp if some git lit up a big fat cigar) but generally no, everywhere must of smelt of smoke, offices buses, trains, and mostly it must have smelt normal. Now, even if someone goes outside for a smoke, the smell on their clothes when they come back in is enough to leave a bad smell

[Biospace]

...
20years ago what were we breathing in

Overall less pollution than what had gone before, per vehicle, but increasingly more nano particulates which arrived with high pressure injection ("common rail") in the late 90s. Rather than the lungs filtering out particulates, these can pass directly into the blood stream and are associated with circulatory disease.

The EGR systems are often coked up so don't function properly. Whoever thought up the wheeze that it was a good idea for an engine to eat its own exhaust didn't give any thought to its maintenance.

There are better ways of reducing NOx, this is the cheapest, a bolt-on which only serves to point out the stand-alone ICE is reaching the end of its useful life for mass personal transport. I've noticed that road speeds appear to have fallen over the last decade or so, while engines have grown more powerful. An engine which rarely uses its potential and which uses less of its capacity at any time can tend to run with higher emissions.

Real world figures for exhaust emissions are not always what manufacturers and Government would have us believe anyway - many are reported to run significantly over the class limits, typically (despite the VW emissions scandal) it has been German diesels with emissions closest to or under them.

Fossil fuels generally have a dirty burn which is somewhat ameliorated by a cocktail of additives. Unfortunately, when combusted these form toxic compounds.

[Mick F]

It's not just older diesels.
It seems to me, that some cars smell more than others. Not the age of them.

I had a thread on here .......... can't be bothered to search ........... and I sort of blamed it on the health of the car or the sort of diesel they were buying. New ones, old ones, makes no difference.

They should all be off the road.

[Nigel]

Changes in diesel fuel from 2008: 2009 change to low sulphur fuel. Later change (can't find a date) to add a percentage of "bio diesel" which has different volatile components.

Most of the observation may be due to a mixture of maintenance of vehicle, age related decay of parts, and sensitivity of individual to smells. I suspect those are bigger impact than the fuel itself.

[pwa]

I get the impression there are a lot fewer diesel cars on the road now. Why, I wonder, would anyone buy a new one now? We have a small motorhome with a diesel engine, dating back to about 2010, and if it has been idle for a while it isn't something you would want to stand beside as it warms up. Once warmed up its emissions are invisible, but I can get the occasional diesel taste if I walk past it while it is running. It is low mileage, so these commercial van engines must have been like that in the past, too.

[3speednut]

Being an asthma sufferer I can say that modern diesels affect me more than old school diesels, I've been in buildings with old school HGVs running full of choking fumes and had no asthma affect but one mouthful of modern diesel fumes and I can't breathe , so regardless of what the stats say in my book they are worse than ever.

[pq]

I did a little 3 day tour earlier in the year. It turned out the route was popular with motorised 2 wheelers (they stank) and two very large groups of classic cars passed me (they stank nearly as much as the 2 wheelers). I didn't notice any unpleasant smells from other vehicles apart from the occasional smoky diesel. I drive a big 2008 Merc with an intergalactic mileage and a small diesel engine. It produces no visible smoke, doesn't smell and has been properly maintained since I owned it. Here in France we are supposed to apply for a sticker saying how polluting your vehicle is, and oddly, my old Merc does OK, it's in a lower polluting band than the similarly sized 2008 diesel VW I had before - but that was stinky and smoky. It meant that until they chickened out, the VW wouldn't have been allowed in some French cities but the Merc would. I do think that even my relatively clean Merc shouldn't be on the road, especially in cities, but I can't justify spending the money it would cost to get something cleaner

[Blondie]

20years ago what were we breathing in

Likely less of the bad stuff, as the volume of diesel consumed is 50% higher than 20 years ago. Just look at congestion compared to years ago. The number of motorised vehicle miles is increasing unabated so far.

[Bmblbzzz]

It turned out the route was popular with motorised 2 wheelers (they stank)

Probably two-stroke engines. The smell is from the oil that gets burnt (for lubrication) in the combustion chamber. They would be petrol engines but there are also two-stroke diesel engines, used mainly in marine applications; apparently the most efficient of all internal combustion engines in terms of energy in converted to energy out.

[al_yrpal]

Most Lorries and a high proportion of vans are diesel. Many trains are diesel. Electric lorries are becoming available.

Al

[Biospace]

Being an asthma sufferer I can say that modern diesels affect me more than old school diesels, I've been in buildings with old school HGVs running full of choking fumes and had no asthma affect but one mouthful of modern diesel fumes and I can't breathe , so regardless of what the stats say in my book they are worse than ever.

My MoT tester from years ago would second that - he wasn't affected by idling diesels until the first common rail varieties appeared in the early 2000s. The first one left him feeling dizzy, sick and with his eyesight temporarily affected, he took an afternoon to recover and said he felt off it for a week. From then on, his country workshop doors were left wide open and no modern diesel was left idling.

There was a decade of clean looking exhausts but still many particulates, just that they'd been made invisible. They remain in suspension for far longer than larger sooty particles and are re-suspended more easily by passing traffic.

[Cowsham]

It turned out the route was popular with motorised 2 wheelers (they stank)

Probably two-stroke engines. The smell is from the oil that gets burnt (for lubrication) in the combustion chamber. They would be petrol engines but there are also two-stroke diesel engines, used mainly in marine applications; apparently the most efficient of all internal combustion engines in terms of energy in converted to energy out.

I don't think so -- the Detroit diesel fire pump engine used in many large sprinkler systems is a two stroke 3 cylinder diesel -- ( a fascinating engine ) but I think it's main claim was that it is much smaller than it's equivalent 4 stroke version but produces more power ie more power / size, after all it's a fire pump engine and hopefully doesn't need to be efficient just work well when required.

Two stroke motorcycles are more thirsty than equivalent four strokes but do produce more power from a smaller lighter engine.
However
The development of four strokes and abandonment of two strokes has meant that the modern four stroke is now on a power with the last of the race two stroke bikes. Lap times around Donington ( national circuit -- I think ) are similar.

I'm convinced that electric cars and bikes will eclipse lap times set by ice race cars and bikes. There's so much more torque and far superior control -- the drivers and riders will have to do astronaut style G force training to sit in / on them.