What is the difference between diesel fuel and petrol (gasoline)?

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Offline lightarrow

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Thank you for the welcome Lightarrow but I can agree with few if any of the points you make.
I don't know what a Sanity Department does but it clearly doesn't do much to do with engine emissions in the real world.
This clearly show that you are talking about another planet. Sanity departments (at least here in Italy!) are continuously studying, sampling, making conferences on this subject. If you don't believe what I say, we have nothing to discuss anylonger.
Maybe you sell diesel vehicles or you are pushing for it...
Studying, sampling and making conferences about what exactly? As you have clearly not studied or sampled much petrol emissions if you think they are safer than diesel ones.
It's not my opinion.
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have you studied or sampled much of the emissions from the new "petrols that work like diesels but still have the most unreliable bit the High-tension ignition system" the FSI and other direct injection engines they produce NOX as well.
Pressures inside an FSI petrol engine are about 10 times lower than those in a corresponding common rail diesel. So NOx are much lower.
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Diesel virtually eliminate their NOX with EGR (Exhaust Gas recirculation, in case your sampling and studying hasn't got that far).
You are dreaming. You don't even realize the difference in smell from a diesel engine exausts and a petrol engine. I studied and made chemistry and I can tell you the smell from diesel exausts means great amounts of NO2. If you don't believe it, make this simple experiment: dissolve a piece of metallic copper in nitric acid and observe the red smoke it forms; then remember the smell it has. Then look up a chemistry book looking for all the physical, chemical and tossicological properties of NO2.
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I fear the Italian version of SANITY (I wonder if you mean Sanitary?) is way out of step with Audi, VW, BMW, GM, Ford, Citroen, Peugeot, Renault and even Errrrr FIAT who all see diesel as the only way of meeting both CO2 and air quality standards.
What car companies and governements told us are not what data analysis show...Furthermore, they make us focus our attention on the CO2 problem, instead of much worse problems. Do keep breathing particulates and NOx at these levels and we won't have to worry about dissolving poles, because we will all be ill before.
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Alcohol is a dead end it is expensive and energy hungry to produce and wasteful of huge areas of land - much more land is needed to produce the same energy value of alcohol than of bio-diesel. It is also more dangerous and more difficult to store and more wasteful in use due to losses by evaporation.
Bio-diesel comes directly as liquid from trees? Making it needs energy too. Alcohol is not more volatile and more difficult to store than petrol.
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However, Yes you are right on one point - if you can't see that and can't see past your clear and undoubted prejudices - you have nothing more to say on a matter you clearly have little relevant knowledge of.
And NO I do not sell diesels - I drive them with a clear conscience and the sooner I can drive anywhere using waste vegetable oil as fuel my conscience will be even clearer
Maybe your conscience, but not the air we all breathe, unfortunately.

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Offline scanner

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I'll connect a pipe to my diesel exhaust and you connect one to your petrol exhaust and then breath it in for a few minutes - I'll have a cough (maybe)- you won't have a cough you'll have a funeral.

I repeat: petrol emissions kill instantly and there are millions of suicides (including a good friend of mine) to conclusively prove that.

Diesel emissions MAY kill in decades and even that hasn't been proved yet and neither you nor anybody else can produce one single person who can be conclusively proved to have died solely as a result of diesel exhaust fumes.

If that friend of mine had followed my advice and had a diesel car he might still be alive, he certainly wouldn't have died in his car.

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Offline rosy

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As has been remarked in this and another thread, this forum thread has been linked from some BBC page somewhere... I don't know where, since no-one's posted the link.

This is rather unfortunate since this forum (being an entirely open discussion area) contains quite a lot of interesting and well argued material posted by individuals who have serious background knowledge or a good record in checking their facts, in response to questions about interesting areas or science and research. However, the diesel/petrol debate is sufficiently contentious (and enough people have a stake in terms of wanting to believe they've made the right choice of car) to fall prey to the not uncommon problem of people with Strongly Held Views shouting louder, longer and more often than those with a more measured viewpoint.

I can only remark, for the benefit of anyone who hadn't already grasped this fact, that all open discussion areas are only as informative as the people posting to them are informed. Some contributors are pretty reliable, and I shall cite Chris and Daveshorts as examples because I know both (and their trackrecords) fairly well, although this is by no means meant to cast aspersions on anyone else (or not anyone in particular).

For new vistors... the quality of debate on this thread is depressingly low, overendowed with ad hominem attacks, and not in my view (as a site regular) typical of this forum.. tho' it's not unheard of either.
Whilst I'm addressing any new visitors, I may as well point out that as well as the forum this site has a load of other content, including a lot of articles on various scientific topics and podcasts of the Naked Scientists radio show, neither of which are afflicted with underinformed rants.

(Apologies, I'm going to cross post this to the feedback thread too.)

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Offline elegantlywasted

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I'll connect a pipe to my diesel exhaust and you connect one to your petrol exhaust and then breath it in for a few minutes - I'll have a cough (maybe)- you won't have a cough you'll have a funeral.

I repeat: petrol emissions kill instantly and there are millions of suicides (including a good friend of mine) to conclusively prove that.

Diesel emissions MAY kill in decades and even that hasn't been proved yet and neither you nor anybody else can produce one single person who can be conclusively proved to have died solely as a result of diesel exhaust fumes.

If that friend of mine had followed my advice and had a diesel car he might still be alive, he certainly wouldn't have died in his car.


Uhh I have a small problem with the statement that petrol emissions kill "instantly"... Years ago, a friend of the family, on a bet (he was 8) put him mouth to a tail pipe of his fathers Ford while the car was running. Although he was terribly sick (nasty cough for months) and had some pretty nasty burns to his face, he isnt dead. Actually he plays for the farm team of an NHL hockey team... Definatly isn't dead, definatly now a professional athelete.
« Last Edit: 15/02/2007 22:04:01 by elegantlywasted »
-Meg

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Offline elegantlywasted

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And rosy... excellent post.
-Meg

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Offline daveshorts

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Petrol engines do produce more carbon monoxide than a diesel and it was unfortunately a common way to commit suicide, however if your car has a catalytic converter fitted (anything newer than at least 20 years old) the platinum and palladium catalysts help oxygen in the exhaust gassed to oxidise the CO into CO2, and I think the  resulting exhaust is no longer very poisonous. Possibly the only way it could kill you is by a shortage of oxygen, but that is going to be quite a challenge.

In the UK an old car with not catalytic converter will fail it's MOT with 5% CO and one with a Converter will fail at 0.2%, apparently, and most cars will do a lot better than this. Possibly a problem if you tried to breath it directly, but will take at least 10 times longer than the hour or so it used to take. I can't find any figures for diesel CO emmision annoyingly.

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another_someone

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Petrol engines do produce more carbon monoxide than a diesel and it was unfortunately a common way to commit suicide, however if your car has a catalytic converter fitted (anything newer than at least 20 years old) the platinum and palladium catalysts help oxygen in the exhaust gassed to oxidise the CO into CO2, and I think the  resulting exhaust is no longer very poisonous. Possibly the only way it could kill you is by a shortage of oxygen, but that is going to be quite a challenge.

In the UK an old car with not catalytic converter will fail it's MOT with 5% CO and one with a Converter will fail at 0.2%, apparently, and most cars will do a lot better than this. Possibly a problem if you tried to breath it directly, but will take at least 10 times longer than the hour or so it used to take. I can't find any figures for diesel CO emmision annoyingly.

CO2 is far less toxic than CO, but as far as I am aware it is still toxic (i.e. you will die sooner breathing in an atmosphere of CO2 than breathing in an inert atmosphere - e.g. N2 or He).

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Offline scanner

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Here is the link to the BBC page with the link to this Topic.
newbielink:http://www.bbc.co.uk/radio4/science/homeplanet_20070213.shtml [nonactive]
If you object to having this forum quoted in this way please take it up with the Producers of the Programme - "Pier Productions"



Petrol engines do produce more carbon monoxide than a diesel and it was unfortunately a common way to commit suicide, however if your car has a catalytic converter fitted (anything newer than at least 20 years old) the platinum and palladium catalysts help oxygen in the exhaust gassed to oxidise the CO into CO2, and I think the  resulting exhaust is no longer very poisonous. Possibly the only way it could kill you is by a shortage of oxygen, but that is going to be quite a challenge.

In the UK an old car with not catalytic converter will fail it's MOT with 5% CO and one with a Converter will fail at 0.2%, apparently, and most cars will do a lot better than this. Possibly a problem if you tried to breath it directly, but will take at least 10 times longer than the hour or so it used to take. I can't find any figures for diesel CO emission annoyingly.


Correct IF a catalyst is fully warmed up and working properly, the catalytic effect being temperature critical (that's why your car has to be fully warmed up for the MOT test). However that takes quite a while, much longer than most people think and in cold weather it can be 15 miles or so depending on driving conditions and until that happens a cat equipped car is actually pumping out more harmful emissions than a non cat equipped one because fitment of the cat causes it to run less efficiently - approx 10% worse.

CO is toxic it combines with something in the blood, Red Corpuscles maybe? and prevents them forming Oxyhaemoglobin  and making Carboxyhaemoglobin instead (perhaps any haematologist who reads this could verify/correct my recollections from schooldays).

CO2 is not toxic but inert (SFAIK) and would kill in just the same way as any inert atmosphere that did not contain any oxygen. It is the lack of oxygen that kills not the CO2 - it's how CO2 fire extinguishers works as well.

How ever little CO a modern fully warmed up catalyst equipped petrol engine produces it is still more than any diesel exhaust emits, as diesels always operate with an excess of Oxygen and CO can only form when there is a deficit of Oxygen (once again SFAIK).

Modern diesels operating on modern Ultra low sulphur diesel or even better totally sulphur free bio-diesel easily meet the same emission standards as catalyst equipped petrol engines whilst using much less fuel and producing much less CO2 and they do not need a Lambda sensor and all the inherently unreliable electronics associated  with it to do so.
Less fuel = Less emissions = Less trouble for the planet and all who live on it.
« Last Edit: 16/02/2007 00:04:29 by scanner »

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Offline lightarrow

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Petrol engines do produce more carbon monoxide than a diesel and it was unfortunately a common way to commit suicide, however if your car has a catalytic converter fitted (anything newer than at least 20 years old) the platinum and palladium catalysts help oxygen in the exhaust gassed to oxidise the CO into CO2, and I think the  resulting exhaust is no longer very poisonous. Possibly the only way it could kill you is by a shortage of oxygen, but that is going to be quite a challenge.
In the UK an old car with not catalytic converter will fail it's MOT with 5% CO and one with a Converter will fail at 0.2%, apparently, and most cars will do a lot better than this. Possibly a problem if you tried to breath it directly, but will take at least 10 times longer than the hour or so it used to take. I can't find any figures for diesel CO emission annoyingly.
Correct IF a catalyst is fully warmed up and working properly, the catalytic effect being temperature critical (that's why your car has to be fully warmed up for the MOT test). However that takes quite a while, much longer than most people think and in cold weather it can be 15 miles or so depending on driving conditions and until that happens a cat equipped car is actually pumping out more harmful emissions than a non cat equipped one because fitment of the cat causes it to run less efficiently - approx 10% worse.
CO is toxic it combines with something in the blood, Red Corpuscles maybe? and prevents them forming Oxyhaemoglobin  and making Carboxyhaemoglobin instead (perhaps any haematologist who reads this could verify/correct my recollections from schooldays).
CO2 is not toxic but inert (SFAIK) and would kill in just the same way as any inert atmosphere that did not contain any oxygen. It is the lack of oxygen that kills not the CO2 - it's how CO2 fire extinguishers works as well.
How ever little CO a modern fully warmed up catalyst equipped petrol engine produces it is still more than any diesel exhaust emits, as diesels always operate with an excess of Oxygen and CO can only form when there is a deficit of Oxygen (once again SFAIK).
Modern diesels operating on modern Ultra low sulphur diesel or even better totally sulphur free bio-diesel easily meet the same emission standards as catalyst equipped petrol engines whilst using much less fuel and producing much less CO2 and they do not need a Lambda sensor and all the inherently unreliable electronics associated  with it to do so.
Less fuel = Less emissions = Less trouble for the planet and all who live on it.
Yes, catalized petrol engines produces CO before the catalitic exaust is hot; but diesel engines produces NO2 always. CO is extremely toxic, we all know; NO2 is extremely toxic AND carcinogenic; it also gives a combined effect with HC (uncombusted hydrocarbons).

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Offline scanner

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Please supply a link to any information that NOX is carcinogenic as that is news to me and I have never heard it suggested anywhere else than in this forum.

In fact a google turns up this reference

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How likely are nitrogen oxides to cause cancer?

The Department of Health and Human Services (DHHS), the International Agency for Research on Cancer (IARC), and the EPA have not classified nitrogen oxides for potential carcinogenicity.
that took all of 2 seconds to find..................and if THEY especially the EPA can't find a link how can you?

You really do need to take your, blinkers off and get real. Stating LIES as facts just shows you up as misinformed and muddle-headed.

And just so you know, petrols also produce uncombusted hydrocarbons not only diesels, so don't try that form of smearing to try and make your weak and unsubstantiated case stick either.

Diesels pollute, but petrols pollute more simply because they produce much more exhaust volume from a more polluting fuel.

I think you should go away and do some up to date "sampling and studying" before sharing your "knowledge" with the world.
« Last Edit: 17/02/2007 16:52:00 by scanner »

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Offline snipez999

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Hi there.
I own a diesel car, but was a petrolhead by habit for over 20 years.
I'm no techy, by any means, but if my car can do twice the mpg of my old petrol car; go twice as long between services; need less replacement parts; reach peak torque in half the engine revs and be safer for everyone concerned in the (God forbid) case of a serious accident (by carrying less easily combustible fuel) then isn't that a good thing?
 
 

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another_someone

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I think one question one has to ask is which NOX?

Nitrous oxide (technically not an NOX because it is N2O) has long been used in medicine, and I have not heard of it being linked as a carcinogen.

In theory, I suppose any gaseous oxide, being an acid, can cause all sorts of cellular damage, and dissolved NO2 would be one of the more potent acids.

NO is a normal part of our metabolism, although that simply means that in the right doses it will not be significantly harmful, but equally many things that are a natural part of our metabolism, if absorbed in excess, can indeed be harmful.

So, I think one should maybe be more careful than simply to lump all NOXs together (excepting that they are all potent acids, just as SOXs or even, to a lesser extent, COXs are).

As for accusing people of lying, I do not think that is in order at all.  We all have our own sources of knowledge, and whether in one case you are in error, or another case Alberto is in error - it is a very different matter to suggest that the error was by malicious intent (which is what the word 'LIES' implies).
« Last Edit: 17/02/2007 21:39:16 by another_someone »

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Offline ROCKETRON

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Lightarrow i have never heard of NO2 being "extremely toxic and carcinogenic" and certainly not on the same scale as CO as suggested in your post. Scanners quote from Google sounds about right to me. As i said in my previous post i am surprised that the BBC is linking to this site about a debate between petrol and diesel when people are just quoting from normal press bias against diesels and quoting theories as fact.

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another_someone

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NO2 may not be listed as a carcinogen, but it does seem consistently listed as a major component in photochemical smog, which certainly does have a range of health issues associated with it, even if it may be debateable if cancer is high on that list.

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Offline scanner

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Sorry if it isn't true it's a lie, but just to placate anybody who thinks that is too strong I'll settle for terminological inexactitude and for my taste too many terminological inexactitudes are spread in the (unfathomable to me) crusade some supposedly knowledgeable people seem to have against diesel.
They seem happy to completely misrepresent and exaggerate every perceived fault of diesel but conveniently ignore all the (too my mind) far more serious faults of petrol - Volatility, flammability, toxicity, benzene newbielink:http://www.epa.gov/ttn/atw/hlthef/benzene.html [nonactive] or MTBE newbielink:http://www.epa.gov/oms/consumer/fuels/mtbe/mtbe.htm [nonactive] (both total environmental disasters) wastefulness and last but not least excessive CO2 emissions.

Whatever the oil industry try to do the "improve" petrol's green credentials just seem to make it ever worse for the environment.

Diesel is a safer, more economical fuel that releases less overall in the way of harmful emissions.
Cars powered by diesel are less tiring to drive due to the more relaxed way they provide motive power. They are far easier to drive in an economical manner and far more likely to actually return the MPG figure claimed for them, unlike the petrol-hybrid white elephants
newbielink:http://www.consumeraffairs.com/news04/2005/hybridwatch02.html [nonactive]

So far as I'm concerned diesel in the form of bio-diesel is the only fuel that offers any large scale  long term hope for the internal combustion engine.

Whether or not that is a good thing is another argument......................

 

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Offline scanner

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NO2 may not be listed as a carcinogen, but it does seem consistently listed as a major component in photochemical smog, which certainly does have a range of health issues associated with it, even if it may be debateable if cancer is high on that list.
If NOX from diesel is the cause of photochemical smog why is the most vehemently anti-diesel city on earth Los Angeles (where is is virtually impossible to own a diesel car) so afflicted with photochemical smog?

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another_someone

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If NOX from diesel is the cause of photochemical smog why is the most vehemently anti-diesel city on earth Los Angeles (where is is virtually impossible to own a diesel car) so afflicted with photochemical smog?

I did not use the words "from diesel", only that NO2 (whatever its source) is considered a major component of photochemical smog.

One reason why Los Angelas is one of the cities (there are a few others) that is particularly badly effected by photochemical smog is because the mountains around the city do not allow proper dispersal of the pollutants, so they get seriously concentrated into the valley in which Los Angeles sits.  If Los Angeles were situated elsewhere, with a different geography, the same levels of pollution pumped into the atmosphere would be more widely dispersed, and cause fewer local problems.

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Offline scanner

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You may not have done, but others on here seem convinced that diesel produces most if not all the NOX in the world - possibly even whilst smoking a cigarette or two, sat in front of an open (or gas) fire or in a house heated by gas or electricity.

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another_someone

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You may not have done, but others on here seem convinced that diesel produces most if not all the NOX in the world - possibly even whilst smoking a cigarette or two, sat in front of an open (or gas) fire or in a house heated by gas or electricity.

From what I read, it seems that NO2 in photochemical smog is caused substantially by NO2 and O3 production caused by an interaction of NO, unburnt hydrocarbons, and sunlight.  Most of the NO2 does not seem to be directly coming from the exhaust of vehicles, but as a secondary product created in the atmosphere.

Thus, pumping out high levels of NO alone will not do it, it requires both the NO and the hydrocarbons.

As has been indicated here, the vehicles that produce a lot of one, tend to produce less of the other.  Thus one might argue the worst case scenario is for a mix of vehicles each adding their own contribution.  Where that leaves us with regard to which type of vehicle is more to blame for the outcome is a more difficult question.
« Last Edit: 17/02/2007 22:56:50 by another_someone »

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Offline scanner

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Well I trust Alberto will believe you..........


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another_someone

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Well I trust Alberto will believe you..........

I am not some supreme being that expects unquestioning belief, and should you or Alberto choose not to believe me (for whatever reason), I should not be mortally offended, nor accuse you or he of heresy or blasphemy.  The only thing I do ask is the you trust that I am telling the truth as I know it (and being human, I am as susceptible to error as anybody else).  I just ask that nobody assume malice or deliberate lies, even if maybe they cannot find cause to agree with me.

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Offline scanner

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Fair enough no one could ask more than that.

If Alberto wants something to worry about this substance newbielink:http://www.dhmo.org/ [nonactive] kills far more people every day than any exposure to NOX from whatever source.

It destroys landscape, infrastructure and technology with equal ease.

All in all it is deadly stuff and we are considering replacing IC engines with motive sources that are said to produce this as their only emission.

Are we mad?

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another_someone

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If Alberto wants something to worry about this substance http://www.dhmo.org/ kills far more people every day than any exposure to NOX from whatever source.

It destroys landscape, infrastructure and technology with equal ease.

All in all it is deadly stuff and we are considering replacing IC engines with motive sources that are said to produce this as their only emission.

Are we mad?

LOL - I first heard about that some many, many years ago - but I do think it still holds a valuable lesson in human gullability.

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Offline Hadrian

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Quote

I am not some supreme being that expects unquestioning belief, and should you or Alberto choose not to believe me (for whatever reason), I should not be mortally offended, nor accuse you or he of heresy or blasphemy.  The only thing I do ask is the you trust that I am telling the truth as I know it (and being human, I am as susceptible to error as anybody else).  I just ask that nobody assume malice or deliberate lies, even if maybe they cannot find cause to agree with me.




i can say that you are one great chap who i have enjoyed a scrap or two with in the past and you never took prisioners on the way and i vary much respect you for it...



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Offline neilep

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Can I just say that me is well happy for asking my question.

Everyone is being so nice and lovely !!!..

Big Big soppy hugs all round.

YAYYYYYYYYYY !!!!






*if you detect even a soupcon of sarcasm...then ewe may be right*
Men are the same as women, just inside out !

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Offline scanner

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If ewer happy then sow are we.

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Offline lightarrow

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Please supply a link to any information that NOX is carcinogenic as that is news to me and I have never heard it suggested anywhere else than in this forum.
In fact a google turns up this reference
Quote
   
How likely are nitrogen oxides to cause cancer?
The Department of Health and Human Services (DHHS), the International Agency for Research on Cancer (IARC), and the EPA have not classified nitrogen oxides for potential carcinogenicity.
that took all of 2 seconds to find..................and if THEY especially the EPA can't find a link how can you?
You really do need to take your, blinkers off and get real. Stating LIES as facts just shows you up as misinformed and muddle-headed.
And just so you know, petrols also produce uncombusted hydrocarbons not only diesels, so don't try that form of smearing to try and make your weak and unsubstantiated case stick either.
Diesels pollute, but petrols pollute more simply because they produce much more exhaust volume from a more polluting fuel.
I think you should go away and do some up to date "sampling and studying" before sharing your "knowledge" with the world.

NOx reacts with amines in biological compounds/tissues forming nitrosamines, which are powerful carcinogens:

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

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Offline lightarrow

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I also would like to precise something:
1. I certainly don't say petrol engines don't pollute; infact I said that, in case, I would prefer alcohol engines (not hydrogen because it would need a lot of energy and so pollution, to get it).
2. I'm not against all diesel engines in general, but against most of the existing ones, because most of vehicle's pollution comes from them (especially lorries, I presume), for example HC, NOx and particulate. Of course petrol engines also produce a huge amount of pollution, but most comes from existing diesels, because most of them are not modern engines (Euro 4, Euro 5, with antiparticulate filters ecc.).
3. In no way I have an interest in imposing my beliefs; I'm only expressing my ideas, which comes from what I have get through different kinds of information means; if they will result to be wrong, I will accept it; it wouldn't be the first time I have something to learn, and a Forum is exactly a place and a mean to exchange ideas and informations. Isnt'it?

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Offline scanner

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So now you claim NOX MAY be a carcinogen IF it reacts with something else - MAYBE.

That is not what you stated as FACT earlier.

Diesels may produce most pollution and it may be the bigger ones that produce most - trucks etc - BUT can you imagine the pollution if all those trucks had petrol engines? What is your alternative to that?

Alcohol may be a good idea but have you studied just how much energy is needed and how much pollution is caused by it's production?
Bio-diesel is far cheaper and easier to produce and produces far more energy at far lower cost. The huge boom in diesel ownership in recent years (certainly in the UK) means that most diesels are less than 3 years old. If all the older ones are to be scrapped think of all the pollution produced when their replacements are manufactured and all the pollution involved in disposing of them.

Pollution produced by use of a car (whatever sort of engine it is fitted with) is relatively small compared to manufacture and disposal.

It is for this reason that hybrids like the Prius are very "UNGREEN" because of the huge extra pollution involved in making and disposing of their battery packs every few years.
« Last Edit: 19/02/2007 17:01:15 by scanner »

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another_someone

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Pollution produced by use of a car (whatever sort of engine it is fitted with) is relatively small compared to manufacture and disposal.

It is for this reason that hybrids like the Prius are very "UNGREEN" because of the huge extra pollution involved in making and disposing of their battery packs every few years.

The battery packs on the prius are Nickel Metal Hydrides, which are still cleaner to dispose of then the lead acid batteries on conventional cars.

I am not sure where you get the idea that the batteries have a short design life, although NHM batteries inherently have a problem with high levels of self discharge, and so can present problems with vehicles that are infrequently used.  I believe the Toyota will be moving to Lithium Ion batterry technology in 2009, which has far less of a self discharge problem.

The other advantage that has not been mentioned about hybrid and electrical cars is the use of electrical (regenerative) braking.  Aside from the energy efficiency this introduces, it also reduces the amount of brake dust generated - which itself is a pollutant.

Ofcourse, all of this depends on the type of driving you are doing - and if you are doing the kind of driving that inherently requires little braking, then this is not an issue.

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Offline lightarrow

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The other advantage that has not been mentioned about hybrid and electrical cars is the use of electrical (regenerative) braking.  Aside from the energy efficiency this introduces, it also reduces the amount of brake dust generated - which itself is a pollutant.
Ofcourse, all of this depends on the type of driving you are doing - and if you are doing the kind of driving that inherently requires little braking, then this is not an issue.
However, the energy lost by acceleration/braking is infact quite a relevant amount of the total energy used, for a car, so the use of electrical braking would considerably reduce a car's fuel consumption, in my opinion.

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Offline lightarrow

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So now you claim NOX MAY be a carcinogen IF it reacts with something else - MAYBE. That is not what you stated as FACT earlier.
NO and NO2 are free radicals. It means: very reactive compounds.
Quote
Diesels may produce most pollution and it may be the bigger ones that produce most - trucks etc - BUT can you imagine the pollution if all those trucks had petrol engines?
Yes, I can imagine it: much less particulates, less HC and NOx. Of course this wouldn't exactly mean pure air, but certainly a little bit better.
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What is your alternative to that?
Alcohol may be a good idea but have you studied just how much energy is needed and how much pollution is caused by it's production?
Not very much, using cellulose fermentation.
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Bio-diesel is far cheaper and easier to produce and produces far more energy at far lower cost. The huge boom in diesel ownership in recent years (certainly in the UK) means that most diesels are less than 3 years old. If all the older ones are to be scrapped think of all the pollution produced when their replacements are manufactured and all the pollution involved in disposing of them. Pollution produced by use of a car (whatever sort of engine it is fitted with) is relatively small compared to manufacture and disposal.
Are you saying that if we have poisonous things the best solution would be to keep them and keep us poisoned? It's a strange way of thinking! (And I'm not referring to diesels only, but to things in general).

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Offline scanner

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You seem to be one of the few people who think NOX is so dangerous in the concentrations produced by diesels and indeed that diesels are a major source. I reckon more NOX is produced by cigarettes and more directly ingested (i.e. straight into the lungs)than from diesels.

Yes and much more Benzene, much more sub-PM10 particulates, much higher overall volume of emissions, more Co, shorter engine life with earlier/higher combustion of lubrication oil causing more smoke, much more rapid exhaustion of a finite resource.

Huge areas of land and enormous distillation plants would be needed to produce enough fuel for thirsty spark ignition truck engines.......... you really cannot be serious, as somebody once said and I still hold that the dangers inherent with making and transporting alcohol are not worth the risk, just one bad accident could kill more people in one go than in years of use.

Whole life costs! You cannot just count "use" toward whether something is "good" or "bad" you have to count from making it to disposing of it as well. The ill effects of getting rid of an old one and making a new one can easily outweigh the ill effects of using one that is maybe not quite as "good" as it could be.

So diesel is now "poisonous" is it - just what is petrol then?

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another_someone

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However, the energy lost by acceleration/braking is infact quite a relevant amount of the total energy used, for a car, so the use of electrical braking would considerably reduce a car's fuel consumption, in my opinion.

In urban traffic, this is certainly the case; but I think one of the reasons why the Prius has proved a little disappointing for some (although it is still very early in the evolution cycle for that technology) is that the same does not hold true for long motorway drives, and it depends upon the type of driving you are doing as to how significant regenerative braking would be.  For Americans in particular, who in may parts of the country don't even have much in the way of bends in the road, and they can just drive on cruise control (something that would be considered highly dangerous in most of Britain, especially the south-east), the benefits of regenerative braking would be marginal at best.

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Offline lightarrow

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In urban traffic, this is certainly the case; but I think one of the reasons why the Prius has proved a little disappointing for some (although it is still very early in the evolution cycle for that technology) is that the same does not hold true for long motorway drives, and it depends upon the type of driving you are doing as to how significant regenerative braking would be.  For Americans in particular, who in may parts of the country don't even have much in the way of bends in the road, and they can just drive on cruise control (something that would be considered highly dangerous in most of Britain, especially the south-east), the benefits of regenerative braking would be marginal at best.
Yes, I forgot that in America, everything is different!

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Offline lightarrow

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You seem to be one of the few people who think NOX is so dangerous in the concentrations produced by diesels and indeed that diesels are a major source. I reckon more NOX is produced by cigarettes and more directly ingested (i.e. straight into the lungs)than from diesels.

Yes and much more Benzene, much more sub-PM10 particulates, much higher overall volume of emissions, more Co, shorter engine life with earlier/higher combustion of lubrication oil causing more smoke, much more rapid exhaustion of a finite resource.

Huge areas of land and enormous distillation plants would be needed to produce enough fuel for thirsty spark ignition truck engines.......... you really cannot be serious, as somebody once said and I still hold that the dangers inherent with making and transporting alcohol are not worth the risk, just one bad accident could kill more people in one go than in years of use.

Whole life costs! You cannot just count "use" toward whether something is "good" or "bad" you have to count from making it to disposing of it as well. The ill effects of getting rid of an old one and making a new one can easily outweigh the ill effects of using one that is maybe not quite as "good" as it could be.

So diesel is now "poisonous" is it - just what is petrol then?
Scanner, I sincerely don't want to go on with this discussion with you and not because I finished my arguments.
Bye.
Alberto.

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Offline scanner

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Of course you haven't finished with your arguments because you don't have a valid position to argue from. All you do is repeat your opinion of flawed and biased data. IF diesel was anywhere near as poisonous as you claim it would be banned just as tetra-ethyl lead was in petrol and benzene has partially been - 1% of petrol can still be a KNOWN (not suspected or just plain possible-maybe) carcinogen.
A move away from diesel as the MAIN motive fuel to petrol or even alcohol would result in a huge overall increase in pollutants especially CO2. Your "solution" would be totally unsustainable.

Until we can stop using the IC engine all together, we need to continue using the one which has the least OVERALL ill-effects and at present most sensible observers agree that is the diesel and that is why research into making it even cleaner is progressing so fast.

Please update your "studying and sampling" to drag yourself kicking and screaming into the 21st century - both diesel engines and diesel fuel have improved hugely in the last few years and I consider your views need to catch up.

Goodbye

Stefano

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paul.fr

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Scanner, I sincerely don't want to go on with this discussion with you and not because I finished my arguments.
Bye.
Alberto.

No offence, but i have to say it's about time...


Paul

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Offline ukmicky

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BY SCANNER Until we can stop using the IC engine all together, we need to continue using the one which has the least OVERALL ill-effects and at present most sensible observers agree that is the diesel and that is why research into making it even cleaner is progressing so fast
You are kidding of course, YOU CAN NOT BE SERIOUS ,you talk about people on this forum being blinkered in regards to their bias towards petrol and yet you are doing the same with you bias towards diesel.


I ASK EVERYONE TO DO A BASIC GOGGLE SEARCH ON "How toxic is diesel compared to petrol 2006 "
 
You will find that every study performed by every health organisation on the dangers of diesel pollution , even the world health organisation report that diesel pollution is many times more hazardous to life than petrol.Did you know that diesel is the number one air poluter in California even though it is nowhere near the number one fuel which is petrol.
The World Health Organization has concluded that, globally,particulate matter causes 460,000 premature deaths each year. Diesel engines generate primary particulate emissions – accounting for 20 percent of direct PM10emissions nationally. EPA has projected that by 2010, direct PM10emissions frommobile sources will be over 600,000 tons, with diesel engines contributing nearly 70percent.
____________________________________________________
THIS WEBSITE GIVES A GOOD BASIC RUNDOWN

For over ten years the U.S. Environmental Protection Agency(EPA) has worked to reduce the amount of emissions that die-sel trucks and buses are allowed to release, due to the threat posed to human health and the environment. Much less has been done to clean up diesel fuel and diesel engines than gaso-line alternatives. Diesel fuel not only contains a higher portion of dangerous substances compared to gasoline (as a result of less refining), but also the high-heat combustion in diesel engines allows a larger portion of these substances to form and be released. The high heat in diesel engines creates NOx. NOx reacts with sunlight and Volatile Organic Compounds (VOCs)to form smog, which triggers asthma. The Clean Air Network estimated that in 1997, smog triggered370,000 asthma attacks, and 9,600 emergency room visits in Pennsylvania. Fourteen Americans die every day from asthma. SO2 contributes to par-ticulate matter (soot) and when inhaled, particles of soot get lodged deep in the lungs causing in-fection, and potentially cancer and premature death. CO de-prives the heart, brain, lungs, and other tissues of oxygen.Diesel exhaust contains more than 40 toxic substances, many more than are found in gasoline. The U.S. EPA stated that die-sel exhaust is a ‘likely human carcinogen’, or cancer-causing agent. Studies in California suggest that over 70% of all cancers attributed to air pollution are caused by diesel exhaust.Carcinogens in diesel exhaust include arsenic and benzene. Other toxics include formaldehyde, cyanide, dioxin, ammonia,and 1-3 butadiene which, can cause long-term health problems such as lung, kidney,and nervous system damage, and short-term effects such as skin and eye irritation,and aggravated respiratory problems
http://www.cleanair.org/Air/diesel_factsheet1_danger.pdf
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Diesel fuel contains more energy per litre than petrol and coupled with the fact that diesel engines are more efficient than petrol engines, diesel cars are more efficient to run. Diesel fuel contains no lead and emissions of the regulated pollutants (carbon monoxide, hydrocarbons and nitrogen oxides) are lower than those from petrol cars without a catalyst. However, when compared to petrol cars with a catalyst, diesels have higher emissions of nitrogen oxides and much higher emissions of particulate matter.
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http://www.ace.mmu.ac.uk/eae/Air_Quality/Older/Cars.html
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While diesel vehicles make up only about 10% of vehicles on the road, they are responsible for belching out 80% of traffic emission problems.
http://www.medicalobserver.com.au/displayarticle/index.asp?articleID=7332&templateID=105&sl=1
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Swedish consultancy agency Ecotraffic report ,showed  that the cancer potency of diesel exhaust is more than twice that of petrol cars. If only particulate emissions are considered, the carcinogenic effect of one new diesel car is equivalent to 24 new petrol cars and 84 new CNG cars on the road.
According to a study conducted by the German Federal Environment Agency, diesel is "several dozen" times more cancer-causing than petrol.
http://www.cseindia.org/dte-supplement/air20040331/toxic_risk.htm

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There is no real debate that breathing diesel fumes is hazardous to the publics health. Compared to auto emissions, which are bad enough, diesel fumes are especially noxious
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The World Health Organization reports that three million people now die each year from the effects of air pollution. This is three times the number who die each year in auto accidents.
A 1999 study by Southern California's South Coast Air Quality Management District (SCAQMD) found that diesel soot accounts for 71 percent of the cancer risk from all toxic air contaminants.
Only 2 percent of all vehicles on the road in the U.S. run on diesel, yet diesels account for 27 percent of the smog-forming pollution and 66 percent of the soot produced by all of the nation's motor vehicles.
Over 30 human epidemiological studies have found a link between diesel exhaust and lung cancer.http://www.aacog.com/schoolbus/Parents/Parents.asp


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Diesel engines emit huge quantities of particulate matter, nitrogen oxides and more than 40 toxic compounds that have been linked to cancer and other serious health impacts. Particulate matter is associated with increased asthma emergencies, bronchitis, various cardiopulmonary ailments, cancer, heart disease and premature death. Nitrogen oxides contribute to ground-level ozone formation, smog, and nutrient pollution in waterways. Up to half of the particulate matter measured in the nation’s largest cities comes from diesel tailpipes. Roughly one-quarter of the nation’s nitrogen oxides come from diesel engines. Diesel exhaust (or diesel particulate) has been found to be carcinogenic by the U.S. Environmental Protection Agency, the California Air Resources Board, the World Health Organization and other public health agencies around the world.
http://www.nrdc.org/air/transportation/trk0600.asp

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http://72.32.110.154/media/pressReleases/001120a.asp

http://www.arb.ca.gov/research/diesel/dpm_draft_3-01-06.pdf


http://www.cseindia.org/aboutus/press_releases/press_20040728.htm

I could go on and on but every study or report from every major heath organisation basically concludes that petrol burning cars pollute less and the pollution that they do give out is less hazardous to our health than diesel, so i may as well leave it as that apart from.

Personally over the years i have driven a hundred or so different diesel powerered vehicles and have driven many thousands of miles in them through my work , but give me the choice and i would have jumped into a petrol car or van everytime because Ive prefer the refinement and responsiveness of the petrol . Also when it comes to health and the dangers of different types of fuels i prefer to listen to the experts like  the U.S. Environmental Protection Agency for example.

.
« Last Edit: 22/02/2007 03:42:59 by ukmicky »

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Offline Karen W.

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I live in California and Let me tell you!! LA has tons of diesel cars etc.. Not to mention High numbers of Big Rigs delivering through there daily... Me Husband Having been one !!! There are plenty of disel powered vehicles there despite the veiw taken earlier on there not being accessible or something in LA with their smog factors.. BUNK!!! I am no expert, but LA IS FULL of diesels all varieties!!!

  Michael YOU ROCK!! LOL

"Life is not measured by the number of Breaths we take, but by the moments that take our breath away."

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Offline scanner

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UKmicky I don't deny diesel pollutes or that petrol pollutes or that they pollute differently.

But US research does not apply in the EU as many factors are different not least the quality of fuel. US diesel is dirty unrefined stuff and is not comparable to EU standard fuel in any way - especially bio-diesel and modern high-tech diesels like V-Power and Ultimate. Once again you are only referring to particulates from diesel - PM10s - petrol produces PM2.5s and PM5s why do you ignore these and their ill effects?
NOX yes diesel produces NOX but in very low concentrations and less now than ever dues to ever better EGR systems. But over all diesel produces less total emissions as it's greater efficiency burns less fuel in the first place.

If things are really so bad why is diesel overhaulling petrol hand over fist as the major motive fuel in the EU?

So
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diesel exhaust is a ‘likely human carcinogen’
is it? Just what is the 1% benzene in petrol then?
I am puzzled by the reference to benzene in diesel exhaust, where would that come from there is no benzene in diesel. It is added to petrol to improve octane ratings - diesel doesn't have or need an octane rating and the very reason it is added to petrol is why it WOULDN'T be added to diesel.

All your quotes relate to the USA and as such are a red herring as those conditions do not translate to the EU as very different circumstances apply and have done for a long time. In any case the EPA is well known for inflating it's case against diesel and totally ignoring the ill-effects of petrol.


OK so you prefer petrol engines, so do such paragons of logical thought as Jeremy Clarkson and Tiff Needell. I would be interested to know exactly which models of diesel car you have driven and how recently that was and when you last drove a petrol van as they are now an endangered species.




Ohh and Karen could you let me know EXACTLY what fraction of 1% of the CARS (not trucks, pick-ups or RVs)in LA are diesel powered? UKmicky states that less than 2% of ALL VEHICLES in the USA are diesel powered, so if you take out all the trucks pick-ups and RVs that cannot leave many % to be cars.

Perhaps the California Dept of Transportation could let you have the figure. I don't think it will take that long to add up.

If it is more than I think, I must say how impressed I am with the good sense of some of your countrypersons.


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Offline Morepower

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Sorry to restart an old thread. I read it all with great interest and I can see both sides of the argument. Neither fuel is healthy and I use both fuels. Petrol in my Motorcycle and Diesel in my car. Now as far as I was taught whilst I worked in the Coal mines dust and particulates were a risk to health and I know people who have died from mining related illnesses. We were always told that if you can see the dust it would be filtered out by our bodies defences and the smaller non visible particles were the highest risk. So when we are looking at particulate emissions surely we need to look at total volume regardless of size and be aware that the smaller particulates have a higher health risk. Again we also need to look at not only emissions per liter of fuel used but also per mile or kilometer. If a diesel can go 30% further per liter than petrol we need to look at it over the amount of fuel used and the distance involved. OK cities are hard work due to volume of traffic but we need to look at ways of reducing the number of vehicles in our cities with options based round less localised pollution. I know electric trams and other public transport has emissions which are away from the urban population but as with LA in the US this lack of ventilation or flow of air over the traffic jams will harm more people who come into contact with it.Electric city transport systems powered by rural wind farms are as clean as we can get at the moment. But I digress.
The energy in diesel is potentially greater than in Petrol and in recent months diesel engined cars have not only won world endurance races but European touring car races and these cars are based on the ones we drive. OK they may be tuned engines but they are all 2 litre and turbo charged, which is as close as any race car will get to being similar to ones we drive.

newbielink:http://www.fiawtcc.com/fiawtcc/season/2008/sport_sto1565962.shtml [nonactive]

As you can see if you look at the link these diesel cars are beating petrol engined ones so power is not too much of a problem with good engine management as these engines are limited to 4100 RPM and have limited boost and fuel pressure applied to them. Now I think unfortunately Diesel will be the fuel we look to more in the future and the US market has not got the volume of diesel vehicles partly due to the poor agricultural quality fuel they use, which almost all the more efficient European and Japanese vehicles now cannot use.There are no top spec European diesel engined cars in the US due to the poor quality fuel. Also as a small by product of US fuel pumps which use one fuel gun for all the fuels which causes the first part of any change in fuel required to take the residue of the other fuel in the lines. Mixing petrol with diesel or vise versa is not good. I was also confused with the comment about Benzine in diesel emissions as Benzine is there to increase octane rating and diesel uses Cetane numbers for its rating and benzine has a negative effect on diesels cetane ratings. I do not argue either fuel is unhealthy but long term bio fuels will be more common and bio diesel in modern engines will become cleaner and exhaust gas recycling to clean up the harmful particulates will become more effective as will the use of catalysts which may not be good for the environment when we make them but will cut down on poisoning due to the use of internal combustion engines.

I do not want to get too wrapped up in the whole argument of either fuel as I have not got the experience of a petrochemical scientist or work in the industry. But from a simplistic point of view if we use less fuel per mile and can use technology to reduce emissions of any type I am in favour of that. Petrol has a limited life and E85 fuels are not an answer with older vehicles as they take a lot to convert over as they use more fuel by volume then petrol alone and fuel injected engines in some cases cannot be adjusted to flow enough E85 and it has a lower energy output per litre to work fully where more modern Diesel fuels will work with older diesel vehicles as the basic principle has not changed and the energy per litre will stay fairly constant.   

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Offline Morepower

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Deisel is like kerosene and it is not as explosive as gas, so it doesn't have as much energy potential as petrol, whereas the gas has a higher energy potential.


Diesel has a higher energy content than Petrol.
1 gallon of gasoline = 124,000 Btu

1 gallon of heating oil or diesel fuel = 139,000 Btu

If you have to make a point please get it right and the above quote doesn't allow for the newer European low sulphur fuels which now have helped evolve diesels in Europe so far that they now cannot be sold in the USA due to the poor quality fuel sold in much of the USA. It is almost the same grade as used in farm vehicles (called Red Diesel in the UK) and the stuff used in 3rd world countries.