Why is diesel now bad news?
Discussion
OldGermanHeaps said:
Why isn't there more of a push to lpg? The emissions benefits are clear, and because of the high octane its well suited to turbocharged cars, and its something that can be done right now at low cost.
The problem is that cars designed to run on LPG will be a bag of sh*t on petrol because they will have higher compression ratios and/or more advanced timing to make use of the higher octane - this will have to be backed off significantly for petrol which will result in poor combustion and poor economy.You have to have quite different (more expensive) fuel systems because LPG is "dry" so there is no lubrication from the fuel which leads to increased wear. On a home conversion this is usually overlooked but OEMs would need the systems to be as reliable as petrol equivalents which would push the cost up.
Equally, the energy density of LPG is much lower than petrol, ergo you need a much larger tank which presents packaging issues.
You then also have the same issue as with EVs in that the infrastructure is not there to support LPG in the same way as petrol.
ORD said:
What on Earth are you on about? The air quality problem is literally ALL caused by the diesel fumes from cars, taxis and buses in London. It really is that simple.
As for 'extremely polluting', look up some statistics on how much CO2 and, more importantly, particulates are actually emitted by diesel cars in use (especially after the first couple of years). There is simply too much london traffic to allow any of it to be pumping out those levels of particulates.
As for people knocking out their DPF, that should be an imprisonable offence.
As for 'extremely polluting', look up some statistics on how much CO2 and, more importantly, particulates are actually emitted by diesel cars in use (especially after the first couple of years). There is simply too much london traffic to allow any of it to be pumping out those levels of particulates.
As for people knocking out their DPF, that should be an imprisonable offence.
stavers said:
OldGermanHeaps said:
Why isn't there more of a push to lpg? The emissions benefits are clear, and because of the high octane its well suited to turbocharged cars, and its something that can be done right now at low cost.
The problem is that cars designed to run on LPG will be a bag of sh*t on petrol because they will have higher compression ratios and/or more advanced timing to make use of the higher octane - this will have to be backed off significantly for petrol which will result in poor combustion and poor economy.You have to have quite different (more expensive) fuel systems because LPG is "dry" so there is no lubrication from the fuel which leads to increased wear. On a home conversion this is usually overlooked but OEMs would need the systems to be as reliable as petrol equivalents which would push the cost up.
Equally, the energy density of LPG is much lower than petrol, ergo you need a much larger tank which presents packaging issues.
You then also have the same issue as with EVs in that the infrastructure is not there to support LPG in the same way as petrol.
The best cars used to be the Volvo's estates running on both fuels.
ORD said:
mygoldfishbowl said:
Slight exaggeration. Busted.60-odd percent in London, which is bad enough!
London is surrounded by airports. Up until three miles high an aircraft's engine will kill us all long before my euro 6 van ever does. Then we have all the problems with air conditioning from office tower blocks. Aeroplanes & office blocks do not have diesel particulate filters. mygoldfishbowl said:
London is surrounded by airports. Up until three miles high an aircraft's engine will kill us all long before my euro 6 van ever does. Then we have all the problems with air conditioning from office tower blocks. Aeroplanes & office blocks do not have diesel particulate filters. Foppo said:
And these small particles more on the diesels without D.P.F.harm the children.
That is why anybody removing the D.P.F.should be locked up.
Petrol engines put out smaller and lighter particulates, in greater number. These remain airborne longer and penetrate the lungs more deeply.That is why anybody removing the D.P.F.should be locked up.
Thanks to the use of lead in the past, and benzene now, petrol engines have been harming children since the dawn of the motor car. Lead was used for some 70 years. It was as well known from the introduction as it was when it was finally banned that it harmed children by damaging development of the brain. Europe, especially the UK, persevered with lead long after it was banned in the US.
heebeegeetee said:
Foppo said:
And these small particles more on the diesels without D.P.F.harm the children.
That is why anybody removing the D.P.F.should be locked up.
Petrol engines put out smaller and lighter particulates, in greater number. These remain airborne longer and penetrate the lungs more deeply.That is why anybody removing the D.P.F.should be locked up.
Fastdruid said:
What a load of tosh. The only petrol cars which produce more particulates than diesels are GDI's, these (legally) require a GPF which reduces particulates by a factor of 2000 down to the level of unpolluted air.
It's not a load of tosh. Particulates from petrols are barely visible, are smaller, lighter, remain airborne for longer and penetrate the lungs more deeply.Historically they were in greater numbers, with advances in both technologies they may not be any more.
Then there is the other issue that petrol has never been successful as a fuel without having chemicals which are (and always have been) known to be injurious to human health.
heebeegeetee said:
Fastdruid said:
What a load of tosh. The only petrol cars which produce more particulates than diesels are GDI's, these (legally) require a GPF which reduces particulates by a factor of 2000 down to the level of unpolluted air.
It's not a load of tosh. Particulates from petrols are barely visible, are smaller, lighter, remain airborne for longer and penetrate the lungs more deeply.Historically they were in greater numbers, with advances in both technologies they may not be any more.
Then there is the other issue that petrol has never been successful as a fuel without having chemicals which are (and always have been) known to be injurious to human health.
http://www.air-quality.org.uk/26.php
Air-Quality.org said:
In fact particulate emissions from petrol cars are so low that they are not routinely measured.
Air-Quality.org said:
However recent health concerns about particulate matter have given diesels a less environmentally-friendly image, as have the higher emissions of nitrogen oxides compared with petrol cars. As a comparison, petrol cars produce virtually no particulate matter
Lead has been banned for 17 years in the UK. Benzene is undesirable and regulated to <1% across the EU. Lots of the other "injurious to human health" components to petrol are due to it's nature (as a semi-refined product) rather than by necessity.The only petrol cars that give off any significant amounts of particulates are GDI's and these are now (rightly so) now regulated to require GPF's. PFI engines do not give of significant amounts of particulates. If you're going to spout this as "fact" then provide sources.
eg http://publications.jrc.ec.europa.eu/repository/bi...
Note the graph on page 10 showing that *all* Euro 4+ GDI's and all PFI engines are below the petrol Euro 5 limit (4.5mg/km). Note that Euro 4 came in 10 years ago so we're talking about 10 year old cars.
On the next page you see that once again for PM counts (rather than by mass) PFI is still well under the Euro 5 diesel limit for everything past Euro 4.
Assessment of particle number limits for petrol vehicles said:
G-DI vehicles are found to exhibit diesel-like size distributions [14, 23, 25] but at absolute levels that are about one order of magnitude below those of conventional (non-DPF equipped) diesel
Assessment of particle number limits for petrol vehicles said:
A recent study (27) employed a real time mobility spectrometer to investigate the contribution of solid particles smaller than 23 nm in the exhaust aerosol of a 2009 model stoichiometric G-DI vehicle when tested over the Federal Test Procedure (FTP) and US06 test cycles. The study concluded that 15 to 20% of the total emitted solid particles are smaller than 23 nm. This is smaller than what has been reported for Heavy Duty diesel engines equipped with DPF (15-85% [28], ~90% [29]).
Eg http://www.greencarcongress.com/2014/01/2014014-au...A 2012 report on particulates from gasoline vehicles by the European Joint Research Commission found that gasoline direct injection (GDI) vehicles consistently emit a very high number of particles, with the actual emission levels even approaching those of conventional diesels in some cases.
Port Fuel Injection (PFI) engines, on the other hand, have no trouble in meeting the limits
eg http://www.meca.org/resources/MECA_UFP_White_Paper...
UFP White paper said:
Historically, normally aspirated port-fueled gasoline engines have produced the least PM per mile or per brake horsepower hour, both by particle mass and particle number. As a result, environmental regulations did not even bother to regulate PM from gasoline engines until recently.
UFP White paper said:
In reviewing Figure 8, it can be seen that the LEV II vehicle equipped with a GDI engine emits a level of PM during the Phase 1 cold start portion of
the test cycle that is visually comparable to a conventional diesel engine that does not have a DPF.
the test cycle that is visually comparable to a conventional diesel engine that does not have a DPF.
Fastdruid said:
heebeegeetee said:
Fastdruid said:
What a load of tosh. The only petrol cars which produce more particulates than diesels are GDI's, these (legally) require a GPF which reduces particulates by a factor of 2000 down to the level of unpolluted air.
It's not a load of tosh. Particulates from petrols are barely visible, are smaller, lighter, remain airborne for longer and penetrate the lungs more deeply.Historically they were in greater numbers, with advances in both technologies they may not be any more.
Then there is the other issue that petrol has never been successful as a fuel without having chemicals which are (and always have been) known to be injurious to human health.
http://www.air-quality.org.uk/26.php
Air-Quality.org said:
In fact particulate emissions from petrol cars are so low that they are not routinely measured.
Air-Quality.org said:
However recent health concerns about particulate matter have given diesels a less environmentally-friendly image, as have the higher emissions of nitrogen oxides compared with petrol cars. As a comparison, petrol cars produce virtually no particulate matter
Lead has been banned for 17 years in the UK. Benzene is undesirable and regulated to <1% across the EU. Lots of the other "injurious to human health" components to petrol are due to it's nature (as a semi-refined product) rather than by necessity.The only petrol cars that give off any significant amounts of particulates are GDI's and these are now (rightly so) now regulated to require GPF's. PFI engines do not give of significant amounts of particulates. If you're going to spout this as "fact" then provide sources.
eg http://publications.jrc.ec.europa.eu/repository/bi...
Note the graph on page 10 showing that *all* Euro 4+ GDI's and all PFI engines are below the petrol Euro 5 limit (4.5mg/km). Note that Euro 4 came in 10 years ago so we're talking about 10 year old cars.
On the next page you see that once again for PM counts (rather than by mass) PFI is still well under the Euro 5 diesel limit for everything past Euro 4.
Assessment of particle number limits for petrol vehicles said:
G-DI vehicles are found to exhibit diesel-like size distributions [14, 23, 25] but at absolute levels that are about one order of magnitude below those of conventional (non-DPF equipped) diesel
Assessment of particle number limits for petrol vehicles said:
A recent study (27) employed a real time mobility spectrometer to investigate the contribution of solid particles smaller than 23 nm in the exhaust aerosol of a 2009 model stoichiometric G-DI vehicle when tested over the Federal Test Procedure (FTP) and US06 test cycles. The study concluded that 15 to 20% of the total emitted solid particles are smaller than 23 nm. This is smaller than what has been reported for Heavy Duty diesel engines equipped with DPF (15-85% [28], ~90% [29]).
Eg http://www.greencarcongress.com/2014/01/2014014-au...A 2012 report on particulates from gasoline vehicles by the European Joint Research Commission found that gasoline direct injection (GDI) vehicles consistently emit a very high number of particles, with the actual emission levels even approaching those of conventional diesels in some cases.
Port Fuel Injection (PFI) engines, on the other hand, have no trouble in meeting the limits
eg http://www.meca.org/resources/MECA_UFP_White_Paper...
UFP White paper said:
Historically, normally aspirated port-fueled gasoline engines have produced the least PM per mile or per brake horsepower hour, both by particle mass and particle number. As a result, environmental regulations did not even bother to regulate PM from gasoline engines until recently.
UFP White paper said:
In reviewing Figure 8, it can be seen that the LEV II vehicle equipped with a GDI engine emits a level of PM during the Phase 1 cold start portion of
the test cycle that is visually comparable to a conventional diesel engine that does not have a DPF.
the test cycle that is visually comparable to a conventional diesel engine that does not have a DPF.
Lots of quotes about limits, but I said nothing about limits, and limits are changed all the time anyway. Todays ultra-clean lean-burn is tomorrow's child killer.
I'm sure we can quote from the internet all day long - these might be of interest:
http://www.ft.com/cms/s/0/60b7cc8c-56b2-11e3-ab12-...
http://www.sciencedaily.com/releases/2015/06/15062...
http://www.sciencedaily.com/releases/2012/03/12030...
My point to Foppo is, I think it shows great naievity when someone wags a finger at others.
Edited by heebeegeetee on Monday 10th August 01:19
Hopefully the global shaming of OEMs on diesel technology will lead to European manufacturers adopting a less CO2 focussed strategy.
It's about time we caught up the rest of the world in petrol/electric/hybrid/hydrogen technology and stopped relying on lobbying the EU to flog diesels.
It's about time we caught up the rest of the world in petrol/electric/hybrid/hydrogen technology and stopped relying on lobbying the EU to flog diesels.
Fastdruid said:
Which is actually the point of the report that despite the Euro regs it's made no difference.
Despite increasing regs there has been no decrease in NOx from diesel cars in 15-20years while Petrol cars have 96% less NOx (in the really real world rather than just in the lab) and that even the latest tech (SCR etc) actually has worse NOx in the urban environment.
I can't see Euro 6 making any difference.
Of course pre-catylst petrol emissions contain more NOx and HC than diesels; the same holds true (or did) over time as the cat degrades (which I mentioned in another thread). Data for emissions on cold start-up would be interesting. I can't believe NOx data for the Euro 5 and 6 cat cars will be that different over time. Modern urea systems and absporpton catalysts (NAC) together with combustion controls (EGR, HPCR) provide comparable levels of NOx emissons control for diesels.Despite increasing regs there has been no decrease in NOx from diesel cars in 15-20years while Petrol cars have 96% less NOx (in the really real world rather than just in the lab) and that even the latest tech (SCR etc) actually has worse NOx in the urban environment.
I can't see Euro 6 making any difference.
Add in petrol's poor CO and CO2 (elevated with cats) and it's pretty much a wash as far as environmental impact goes. Petrol's real plus for micro environments are low particulate matter emissions, but particulate traps have brought this to near parity for modern diesels. So, we've come full circle.
The reason for the reverse course on diesel (IMO) is that it is more expensive for manufacturers to use as in interim solution. A 3-way cat has got to be cheaper to fit than a urea system with a particle filter, etc. And what is the point when the real development is moving toward alternative drive tech? The internal combustion engine is done.
scherzkeks said:
Fastdruid said:
Which is actually the point of the report that despite the Euro regs it's made no difference.
Despite increasing regs there has been no decrease in NOx from diesel cars in 15-20years while Petrol cars have 96% less NOx (in the really real world rather than just in the lab) and that even the latest tech (SCR etc) actually has worse NOx in the urban environment.
I can't see Euro 6 making any difference.
Of course pre-catylst petrol emissions contain more NOx and HC than diesels; the same holds true (or did) over time as the cat degrades (which I mentioned in another thread). Data for emissions on cold start-up would be interesting. I can't believe NOx data for the Euro 5 and 6 cat cars will be that different over time. Modern urea systems and absporpton catalysts (NAC) together with combustion controls (EGR, HPCR) provide comparable levels of NOx emissons control for diesels.Despite increasing regs there has been no decrease in NOx from diesel cars in 15-20years while Petrol cars have 96% less NOx (in the really real world rather than just in the lab) and that even the latest tech (SCR etc) actually has worse NOx in the urban environment.
I can't see Euro 6 making any difference.
Add in petrol's poor CO and CO2 (elevated with cats) and it's pretty much a wash as far as environmental impact goes. Petrol's real plus for micro environments are low particulate matter emissions, but particulate traps have brought this to near parity for modern diesels. So, we've come full circle.
The reason for the reverse course on diesel (IMO) is that it is more expensive for manufacturers to use as in interim solution. A 3-way cat has got to be cheaper to fit than a urea system with a particle filter, etc. And what is the point when the real development is moving toward alternative drive tech? The internal combustion engine is done.
https://www.london.gov.uk/sites/default/files/Driv...
NOx emissions for diesels hadn't improved from the launch of the Euro emissions standards to Euro V! Even at Euro VI they're still at the level of a 20 year old petrol car and still many times the limit!
Petrol is by no means all fluffy kittens and roses but ignoring CO2 (which while bad from a global warming POV is not otherwise harmful) the other major nasty is CO and that is just not a problem. Even way back in 1998 (when the Euro limits were far less strict and there were far more petrol cars) it wasn't a problem.
Just have a play with http://www.londonair.org.uk/london/asp/publicstats... and you can see that the sites that are failing are NOx rather than anything else and that is predominately a diesel problem.
Fastdruid said:
NOx emissions for diesels hadn't improved from the launch of the Euro emissions standards to Euro V! Even at Euro VI they're still at the level of a 20 year old petrol car and still many times the limit!
Urea-SCR was implemented in the auto industry when Euro 5 went in force as far as I know. A petrol without a 3-way cat is also a nasty thing (and may still be as the cat ages).Gassing Station | Motoring News | Top of Page | What's New | My Stuff