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Author Topic: What is the difference between diesel fuel and petrol (gasoline)?  (Read 99871 times)

ukmicky

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The problem with diesel is less energy is released when it ignites ,so diesel cars have less power, so there drivers tend put their foot down a bit more and in the end they end up filling up more than petrol car owners.  And on top of that they polute more than petrol driven cars.
Sorry Michael but I think what you say is not correct.
Diesel engines have a greater torque than petrol engines with the same cc. So, If they could run at the same rpm, their power would actually be greater. Infact they actually releases more energy than petrol engines when the same amount of air/fuel mix ignites, because of the greater intrinsic efficiency.
To compare how much fuel a Diesel consumes against a petrol fuel, we should have two engines with the same cc and the same weight of the cars.

Having said this, I personally hate Diesels, however, because of how much they pollute. Have you ever noticed that strange, bleach-like smell coming from modern diesel's exaust? If you haven't, try to do it. That is the smell of nitrogen dioxyde: NO2. Have you ever heard of the poison carbon monoxide CO? Ok. NO2 is 500 times more poisonous. And it's also carcinogenic. Nano particles of the smoke are carcinogenic too. Why these informations are not revealed? When will governments stop being paid from car companies and will tell us the truth?  :(!
But petrol car produces more BHP per litre , jump into a 1600 diesel and then a 1600 petrol and see which one accelerates faster ,the petrol will win everytime.

lightarrow

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The problem with diesel is less energy is released when it ignites ,so diesel cars have less power, so there drivers tend put their foot down a bit more and in the end they end up filling up more than petrol car owners.  And on top of that they polute more than petrol driven cars.
Sorry Michael but I think what you say is not correct.
Diesel engines have a greater torque than petrol engines with the same cc. So, If they could run at the same rpm, their power would actually be greater. Infact they actually releases more energy than petrol engines when the same amount of air/fuel mix ignites, because of the greater intrinsic efficiency.
To compare how much fuel a Diesel consumes against a petrol fuel, we should have two engines with the same cc and the same weight of the cars.

Having said this, I personally hate Diesels, however, because of how much they pollute. Have you ever noticed that strange, bleach-like smell coming from modern diesel's exaust? If you haven't, try to do it. That is the smell of nitrogen dioxyde: NO2. Have you ever heard of the poison carbon monoxide CO? Ok. NO2 is 500 times more poisonous. And it's also carcinogenic. Nano particles of the smoke are carcinogenic too. Why these informations are not revealed? When will governments stop being paid from car companies and will tell us the truth?  :(!
But petrol car produces more BHP per litre , jump into a 1600 diesel and then a 1600 petrol and see which one accelerates faster ,the petrol will win everytime.
As I said, you cannot compare an engine's power in this way, because power is not only given by the mechanical energy from a single cycle (at the same capacity = cc), but from rpm also. You cannot compare, for example a 1600 diesel which max rpm is 4000 and a 1600 petrol which max rpm is 6000; to do this theoretically, you should multilply the diesel power by 6000/4000.

Furthermore, a diesel vehicle is usually lighter than a petrol one of the same cc, so, if you want to compare the power' engine from the vehicle's acceleration, you should also multiply the diesel power by W1/W2 where W1 is the diesel vehicle's weight and W2 the petrol vehicle's weight.

ukmicky

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Furthermore, a diesel vehicle is usually lighter than a petrol one of the same cc, so, if you want to compare the power' engine from the vehicle's acceleration, you should also multiply the diesel power by W1/W2 where W1 is the diesel vehicle's weight and W2 the petrol vehicle's weight.

Sorry i think you will find diesel vehicles are much heavier than petrol equivalent.

A diesel engine may be simpler than a petrol and requires less ancillary components due to the simplicity of its design however the diesel engine runs at a much higher temperature and compression ratio than the petrol variant and therefore requires a much heavier and stronger block which adds greatly to the overall weight of the vehicle.

Also diesel engine's tend to be low revving units and deliver their torque low down in a very narrow band of their rev range meaning they tend to run out of steam very very quickly compared to the petrol equivalent.  Yes get one if you live in the countryside and need low down pulling power for your four wheel drive or if your often towing caravans up steep hills.
Diesel engines also tend to require more frequent servicing in order to prevent their performance from dropping and without them frequent services they also tend to pollute quite a bit more than petrol . They smell more,run on the most unpleasant stuff you can get on your hands or clothes,their noisier especially when they first start and after a few years of service.
Their very inefficient after high millages and cost more to insure and purchase. Why would anyone want one.


Petrol engines are much lighter than diesel engines with many of their components being made out of alloy and are higher reeving compared to diesel counterparts, Their supremely more responsive with the deliverance of their power and they deliver that power across a much broader spectrum of the rev range .  Petrol WINS everytime ask Aston Martin,Ferrari or Porsche .
« Last Edit: 28/06/2007 02:37:13 by ukmicky »

rosy

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The AA have already done all the maths here:
http://www.theaa.com/motoring_advice/running_costs/index.html

It appears at a cursory glance that for the cheapest end of the range diesels have running costs of maybe 1p/mile more than petrol cars whereas at the upper end of the cost range diesels provide significantly better value.

Of course, since this is the AA there's no information whatever about emmissions of carbon, SOx, whatever.

lightarrow

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Furthermore, a diesel vehicle is usually lighter than a petrol one of the same cc, so, if you want to compare the power' engine from the vehicle's acceleration, you should also multiply the diesel power by W1/W2 where W1 is the diesel vehicle's weight and W2 the petrol vehicle's weight.

Sorry i think you will find diesel vehicles are much heavier than petrol equivalent.
Sorry Michael, you are right. I made a mistake, I intended: "...a diesel vehicle is usually heavier than...", exactly for the reasons you write. Apologize!
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A diesel engine may be simpler than a petrol and requires less ancillary components due to the simplicity of its design however the diesel engine runs at a much higher temperature and compression ratio than the petrol variant and therefore requires a much heavier and stronger block which adds greatly to the overall weight of the vehicle.
Also diesel engine's tend to be low revving units and deliver their torque low down in a very narrow band of their rev range meaning they tend to run out of steam very very quickly compared to the petrol equivalent.  Yes get one if you live in the countryside and need low down pulling power for your four wheel drive or if your often towing caravans up steep hills. Or if you never need to feel a quick response whilst travel quickly.
Diesel engines also tend to require more frequent servicing in order to prevent their performance from dropping and without them frequent services they also tend to pollute quite a bit more than petrol . They smell more,run on the most unpleasant stuff you can get on your hands or clothes,their noisier especially when they first start and after a few years of service.
Their very inefficient after high millages and cost more to insure and purchase. Why would anyone want one.
Because modern diesels makes more km with 1 litre of fuel, and because diesel fuel cost less than petrol (at least here!). Of course they don't consider the long-term costs, as you pointed out.
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Petrol engines are much lighter than diesel engines with many of their components being made out of alloy and are higher reeving compared to diesel counterparts, Their supremely more responsive with the deliverance of their power and they deliver that power across a much broader spectrum of the rev range . Petrol WINS everytime ask Aston Martin,Ferrari or Porsche.
At the moment, the higher rate power/weight is of petrol's engines, but, if we don't look at the most performant (sport/race) engines, and we are not interested in high rpm, low fumes ecc., diesels are better. Furthermore diesel engines are improving faster than the corrisponding petrol ones; this is the reason there are much more diesels now than 10 years ago, and it's the reason there will be more. Here in Italy, most modern cars sold are diesel ones! If no improvement on petrol engine's efficiency will be made in a few years, you can be sure that we will see diesels on races too, in the future!
When I bought my car 4 years ago, a 1600 petrol Alfa 147, I made a "nostalgic" choice, because if I bought a diesel one (JTD 1900), I would have had a faster car (acceleration and speed), with lower fuel used! (However, I use GPL, more than petrol).
If I had to buy a new car now, I would still buy a petrol one but only because I hate how much diesels pollute, and because I want to listen to the "real" sound of an engine.
« Last Edit: 05/02/2007 20:42:10 by lightarrow »

ukmicky

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Hi Alberto

Diesel was once very cheap over here in the UK now its on par and on some occasions more expensive than petrol,but these days everything in the UK is expensive.

lightarrow

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The same here. :-'(
Bye Michael.

chris

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This is a really interesting thread, but the one thing we've not done is to explain in any great detail how diesel engines versus petrol engines actually work.

Petrol engines have sparkplugs. The fuel is drawn into the cylinder pre-mixed with air, or injected as the cylinder fills with air as the piston is descending (this is the induction stroke). The piston then begins to ascend again (compression stroke), compressing the cylinder contents, which is the petrol/air mixture. At just before top dead centre (TDC) the sparkplug fires, igniting the compressed mixture, which begins to burn.

Burning hydrocarbons in air produces gaseous products (chiefly oxides of carbon, and water). Since gases take up more volume than liquids, the contents of the cylinder expand as they burn, forcing the piston back down inside the cyclinder (the power stroke). The piston then re-ascends the cylinder, pushing the exhaust gases out through the exhaust valves, and then begins a new induction cycle. (Please note that this is the schema for a four-stroke engine).

A turbo or super-charged engine works slightly differently. In this case power is taken from the engine (usually by driving an impeller in the exhaust) and use to drive a compressor. This forces air into the cylinder during the induction stroke. Because the cylinder contains more air it can burn more fuel and hence produce more energy. And because the amount of air forced into the cylinder increases as the engine speeds up that's why you experience an initial lag in pick up when you put your foot down at low engine speeds.

A diesel engine is different. This has no sparkplugs and instead relies on sheer heat to ignite the fuel. During the induction stroke, the descending piston pulls just air into the cylinder, which is compressed as the piston ascends. Just as a bike pump gets hot when you inflate a tyre, the air being compressed inside the cyclider heats up. In the average engine it probably reaches 700-900 degrees C. Diesel engines have a higher compression ratio, at 20:1, than petrol engines, which usually compress at about a 10:1 ratio.

When the piston gets to the top of the cylinder, the fuel is injected as a fine (atomised) mist. The intense heat of the compressed air causes the fuel to burn, again producing gaseous (high-volume) products that drive the piston down, generating power. A turbocharger in this context works similarly to a petrol turbo - a compressor forces in more air, increasing the compression in the cylinder, the amount of oxygen in the cylinder and hence the amount of fuel that can be burned in the cylinder. The more fuel you burn the more energy you liberate.

Chris

« Last Edit: 12/02/2007 10:34:49 by chris »

neilep

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This is a really interesting thread,




THANK YOU very much Chris.....You've dotted the 'i 's and crossed the 't's

Those diesel engines run HOT !!!

many thanks

another_someone

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Burning hydrocarbons in air produces gaseous products (chiefly oxides of carbon, and water). Since gases take up more volume than liquids, the contents of the cylinder expand as they burn, forcing the piston back down inside the cylinder (the power stroke). The piston then re-ascends the cylinder, pushing the exhaust gases out through the exhaust valves, and then begins a new induction cycle. (Please note that this is the schema for a four-stroke engine).

In my understanding, this would not be very significant.  Most of the volume of matter in the cylinder is already gaseous (mostly air).  The big expansion, as I understood it, was because of the input of heat from combustion, and a hot gas takes more room than a cold gas (which is why, with turbocharged cars, they like to add intercoolers, so you start the air off cooler, so there is even more expansion when the mixture heats up).

chris

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Sure, but you need to consume energy to cool incoming air, pack more air into a cylinder in the first place and then compress it (in a diesel engine this is referred to as adiabatic compression). Burning the fuel liberates large amounts of gas AND heat, both of which cause expansion within the cylinder and hence the ability to extract "work".

Chris


scanner

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As a long term diesel car driver (since 1988) I am, err how do I put this politely - ummmm amazed will do - at the ignorance on here about diesel.
Chris and daveshorts seem to be the only contributors who have the slightest idea of anything to do with diesel.

As for Louise (I think) and the carcinogens? Well my flabber is well and truly ghasted, has she been sniffing petrol?

1 Diesels are way more efficient than petrol engines; my son has a 999cc petrol car that struggles to do much over 40(imperial)MPG and is slow and a pain to drive anywhere as any overtaking has to be planned a week in advance. My daughter drives a similar sized car (same make, but later slightly larger model) that has much more equipment inc. air con etc but it has a 1910cc turbo diesel engine. It does well 50mpg overall and is a pleasure to drive in any type of traffic and cruises easily (on my private test track of course) at 100mph when the engine is doing just 3000rpm. It is way faster, accelerates much quicker (and stronger) and does around 30-40% more to the gallon.

2 Diesel engines used to be much heavier than petrols until makers like Peugeot/Citroen started the trend to dieselising petrol engines with the XUD engine in the mid 80's. Diesel engines now are usually less than 10% heavier than their petrol equivalent.

3 Diesel engines are not about BHP a purely artificial measure of power that is simply the torque (the real strength of an engine that does the work) times RPM times a constant.
Torque is therefore the real measure of how "good" and engine is and diesels typically have over twice the torque of equivalent petrol engine and develop it at half the RPM.
This is NOT a failing as some of you seem to think, but an advantage. Diesels do not HAVE to rev to do useful amounts of work as petrols do and revs are what kill engines as wear increases exponentially as RPM rises. Double the revs and you get 4 times the wear.  This is why diesel engines last much much longer than petrols allied to the fact that diesel fuel lubricates whilst petrol destroys lubrication by washing away the engine oil from the cylinder walls. The "lack" of revs is irrelevant as diesels can pull far higher gearing (how many small petrol engined cars are doing 3000RPM @ 100MPH like my daughter's car - in fact how many petrol cars of any size do that??)

4 Diesel emissions are worse in some respects that petrol but way better in others. CO2 is much lower CO is absent (you can't commit suicide with a diesel exhaust) PM10 particulates may be higher (it depends on the car and the quality of fuel used) but PM2.5s and PM5s are not thought to be any worse than petrol (yes petrols emit particulates too) and current thinking is that the smaller particulates are worse for health as they lodge lower in the respiratory tract and lungs - so petrol fumes might be equally bad for us in that respect, especially now that more diesels are being fitted with particulate traps and petrols aren't.

5 Diesels do NOT run hotter, because they are more thermally efficient than petrols, more heat is converted into power/torque so the engines actually run cooler, even though the combustion temperature is higher.

6 Petrol apologists always conveniently forget about all the nasties in petrol - benzene for one. Benzene is a known carcinogen so toxic that there is NO safe exposure level and petrol gives off benzene even when the engine isn't running. Petrol is also volatile and downright dangerous just look at any car that crashes in any US action film - it has exploded in flames before it even hits the barrier - that just couldn't/wouldn't/doesn't happen with diesel. As someone said you can throw a match in a bucket of diesel and it will go out - just don't try it with a bucket of petrol.

All major car makers, even the US ones (but they won't admit it at home) see diesel as the way to go. Audi even Grand Slammed the Le Mans series with a Tdi diesel car last year and Peugeot are entering a Hdi competitor this year. The Audi was so superior that the petrolheads are trying to change the rules so they have even the slightest chance of winning.

Diesel is the future and once anybody has tried a good one (there are still some bad ones left) few ever go back to petrol.

www.dervhead.com

« Last Edit: 13/02/2007 22:40:25 by scanner »

another_someone

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Scanner has some points, but I don't agree with them all.

No question that diesel has come a long way, but then so too has petrol.

The question of benzene in petrol is, I believe, and unfortunate side effect of having gone unleaded (the old leaded petrols had far less benzene in them, but politically it was not considered wise to make too big a fuss over benzene levels in unleaded if the government were going to sell the idea of replacing leaded petrol with unleaded).

Diesel certainly has much going for it, but it is at best an interim solution, and is politically unlikely to be satisfactory (not least because most political pressure groups want to move away from any petrochemical fuel – although whether they succeed in that is another matter).

The argument that diesels will still provide the same performance as petrol is not in my experience true, although there is no doubt that the gap is closing.  Diesels, with their high torque, can provide quite a bit of flexibility, but the engines still are less responsive to sudden demands for more power.  This is even true when one looks at high compression, long stroke,  petrol engines do not have the responsiveness of square bored engines, but have better efficiency.  Diesel engines just take this to the extreme.

Ofcourse, some of the difference is down to marketing – since diesels are marketed for fuel economy and longevity, they will not be optimised for raw performance.  Given the convergence of the capabilities of the two technologies, it may well be that we are close to designing petrol engines with the same efficiency as diesel, and diesel engines with the same performance as petrol, but the buyers for each market would be looking for different things.

And, yes, a lot of the old reputation that diesels had of being smelly and dirty is now out of date (at least for modern diesel cars) – that is, unless you are going to fill them up with vegetable oil, which can be used to fuel diesels, although it is illegal because motor tax has not been paid on the vegetable oil.
« Last Edit: 14/02/2007 01:29:36 by another_someone »

lightarrow

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First of all, hi scanner! Welcome on this Forum!
As a long term diesel car driver (since 1988) I am, err how do I put this politely - ummmm amazed will do - at the ignorance on here about diesel.
Chris and daveshorts seem to be the only contributors who have the slightest idea of anything to do with diesel.
As for Louise (I think) and the carcinogens? Well my flabber is well and truly ghasted, has she been sniffing petrol?
I'm italian and I have some problems in understanding these terms. However I said that Diesel vehicles pollute the air, more than petrol vehicles (and all people breath the air, not only diesel's drivers); I work in Sanity Department, you can believe me.
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1 Diesels are way more efficient than petrol engines; my son has a 999cc petrol car that struggles to do much over 40(imperial)MPG and is slow and a pain to drive anywhere as any overtaking has to be planned a week in advance. My daughter drives a similar sized car (same make, but later slightly larger model) that has much more equipment inc. air con etc but it has a 1910cc turbo diesel engine. It does well 50mpg overall and is a pleasure to drive in any type of traffic and cruises easily (on my private test track of course) at 100mph when the engine is doing just 3000rpm. It is way faster, accelerates much quicker (and stronger) and does around 30-40% more to the gallon.
As I already said.
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3 Diesel engines are not about BHP a purely artificial measure of power that is simply the torque (the real strength of an engine that does the work) times RPM times a constant.
Torque is therefore the real measure of how "good" and engine is and diesels typically have over twice the torque of equivalent petrol engine and develop it at half the RPM.
As I already said (more or less).
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This is NOT a failing as some of you seem to think, but an advantage. Diesels do not HAVE to rev to do useful amounts of work as petrols do and revs are what kill engines as wear increases exponentially as RPM rises. Double the revs and you get 4 times the wear. 
One moment! This would be true only with tha same piston elongation, because it would mean higher piston's speed (yes, there is not only the piston's movement, but here are the most important wears), but, as you said, petrol engines usually have shorter piston elongation than the corresponding diesels ones.
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This is why diesel engines last much much longer than petrols allied to the fact that diesel fuel lubricates whilst petrol destroys lubrication by washing away the engine oil from the cylinder walls.
This could be true for old petrol engines (without electronic ignition) starting at cold weather. Furthermore, you don't consider all the problems in the long term in a diesel engine; remember that the pressure inside the cylinders is higher and the injectors (for example) causes problems in the long term.
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PM10 particulates may be higher (it depends on the car and the quality of fuel used) but PM2.5s and PM5s are not thought to be any worse than petrol (yes petrols emit particulates too) and current thinking is that the smaller particulates are worse for health as they lodge lower in the respiratory tract and lungs - so petrol fumes might be equally bad for us in that respect, especially now that more diesels are being fitted with particulate traps and petrols aren't.
Which diesel engines are you talking about? Euro 4 or 5 or what? Most of the present diesel engines are Much worse than the petrol ones for what concerns particulates.
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6 Petrol apologists always conveniently forget about all the nasties in petrol - benzene for one. Benzene is a known carcinogen so toxic that there is NO safe exposure level and petrol gives off benzene even when the engine isn't running. 
Most of Benzene and aromatic compounds were replaced by MTBE metil-terz-butil ethere (non-aromatic).
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Petrol is also volatile and downright dangerous just look at any car that crashes in any US action film - it has exploded in flames before it even hits the barrier
I usually don't believe very much on US action films :) It's quite improbable that this happens, actually. Anyway, it's certainly more probable with petrol than with diesel.
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Diesel is the future...
I hope not, with these diesels...
« Last Edit: 14/02/2007 18:22:42 by lightarrow »

scanner

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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.

Fact Petrol fumes kill in minutes diesel fumes MAY kill in decades

Fact Petrol washes lubricant off the cylinder walls in all types of engine the ignition system is irrelevant

Fact Wear increases as the square of engine speed - I accept that different bore stroke ratios will have some effect on ultimate wear, but negligible compared the overall rate of wear. In addition petrols have to be driven at higher revs all the time to achieve the same progress as a diesel, this is both tiring and more intrusive than the relaxed drive in a diesel.

Fact Petrols were actively developed for most of the last century - diesel development only really began in the mid 1980's and is now leaping ahead at many times the rate of petrol development, which has really hit a plateau.

Fact ALL major car makers see diesel as the only way forward with the IC engine, as it is able to run on the widest range of fuels. To produce Ethanol for spark ignition engines to run on, consumes almost as much energy as the fuel releases in use, production of Bio-diesel is much more energy efficient.

Fact Petrol is a volatile, explosive (1000 times more explosive than gunpowder), toxic down right dangerous fuel that in most countries (certainly the UK) is subject to specific and rigorous storage regulation because it is just so damn dangerous.
Diesel is benign, safe and in the case of bio-diesel, bio degradeable, so no special storage regulations apply.

Fact Diesel does not pollute MORE than petrol, just differently, they both pollute and the pollutants in petrol emissions kill much much quicker.
It is strange just how much diesel pollutants are exaggerated and how petrol pollutants are conveniently overlooked
WHY? What vested interests are harmed by any criticism of petrol?

Question?? So diesel injectors cause problems in the long term? Is that the same long term over which PETROL injectors give problems and longer than the SHORT term that petrol spark plugs and ignition systems give problems?.
All engines develop problems, diesels do not develop them any sooner overall than petrols - indeed I would suggest that most breakdown services would tell you it is much longer.
The AA (UK breakdown service) have said that 85% of all the breakdowns they attend are related to the High Tension IGNITION system, so therefore if follows that 85% of ALL breakdowns can only happen with Spark Ignition (i.e. Petrol) cars.

Particulates You persist in believing that petrols do not emit particulates. I will be generous and accept that this is because you have been convinced by the vested interests who defend petrol, that only PM10s matter.
Many would argue, as I said earlier, that PM2.5s and PM5 are far more dangerous as they penetrate deeper into the lungs. The main producers of the smaller particulates are petrol engines.

Benzene and MTBE - so petrol is now SAFER because (known carcinogen with NO safe exposure level) benzene has been replaced by "non-aromatic" MTBE - WOW!!!! I suggest you go off and do a Google and find out just what problems MTBE has caused in the USA.

Finally, if you think petrol is safer than diesel, I'll make you a deal.

We each take 10 litres of fuel - You petrol - Me diesel and we'll walk out into the middle of a nice open space. We will then pour our can of fuel onto the ground, stand in the middle of the puddle and strike a match.

The one who is able to come back here and write about it wins.






Hadrian

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We each take 10 litres of fuel - You petrol - Me diesel and we'll walk out into the middle of a nice open space. We will then pour our can of fuel onto the ground, stand in the middle of the puddle and strike a match.

The one who is able to come back here and write about it wins.


Well after a few hours I dropped my match and you what, the petrol was all gone? Funny that....LOL  ;D

scanner

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SMSLOL

Same with the Bio-diesel; Ohh except that it hasn't left a poisoned toxic patch on the ground and released a lethal dose of Benzene into the atmosphere.

Hadrian

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emmmmmmmmm  i love the smell of Benzene in the morning............LOL

you got me there OK but still i did not burn and i got back first to write... so do i win still LOL  ;D




scanner

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If you read the rules it said "Stand in the puddle and light a match".

If you wait for it to evaporate.....

Either

1 I've lit my match and got back here (safely) to post a reply long before you possibly could.

or

2 You are no longer stood in said puddle, because said puddle is no longer there and I win by default.

or

3 You play by the rules and get crispy.

skelo

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emmmmmmmmm  i love the smell of Benzene in the morning............LOL

you got me there OK but still i did not burn and i got back first to write... so do i win still LOL  ;D





Lets alter the rules slightly.

To save any possible cheating, how about both of us choose a liquid. Either petrol or diesel, i choose the diesel.

I pour diesel over myself, you get the farmer to pour petrol over you. I light a match immediately after pouring the fuel over myself, the farmer then lights a match immediately after pouring the petrol over yourself then drops it on your fur coat.

Let see who becomes sunday lunch.

I really don't understand, why there is so much anti-diesel argument here. Scientists are supposed to see through the lies and hypocrisy, and base there judgements on fact and logic.

Can you guys not see the simple facts put in front of you?
Diesel is the fuel of the current, and the future.

Cheers
Skelo

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...
« Last Edit: 15/02/2007 08:33:01 by lightarrow »

lightarrow

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I really don't understand, why there is so much anti-diesel argument here. Scientists are supposed to see through the lies and hypocrisy, and base there judgements on fact and logic.
Can you guys not see the simple facts put in front of you?
Diesel is the fuel of the current, and the future.
About the fuel for the future I certainly don't stand for petrol; I would prefer alcohols. About diesel, I really hope that, at least, NOx emissions will go down drastically, soon.

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Well after a few hours I dropped my match and you what, the petrol was all gone? Funny that....LOL  ;D
Yes causing the production of low level ozone and trashing some DNA with all the benzene released.

Neither petrol or diesel are particularly nice, I have to say I would prefer diesel in many of the ways that scanner has said. but both fuels are unpleasent overall, and produce lots of CO2 and in the long term finding something that will work electrochemically (eg a in fuel cell) means we are not thermodynamically limited to a 30-40% efficiency.

scanner

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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.
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. Diesel virtually eliminate their NOX with EGR (Exhaust Gas recirculation, in case your sampling and studying hasn't got that far).
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.

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.

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
« Last Edit: 15/02/2007 12:25:46 by scanner »

ROCKETRON

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 I noticed on the BBC website that they are providing a link to this site on the “Petrol versus diesel” debate. When I looked at this debate I was utterly amazed that the BBC obviously didn’t get anybody with a modicum of knowledge to look at the ridiculous anti-diesel statements being stated as fact on this website. It seems to me that with the exception of Scanner who actually explained the real facts, most of you are quoting from the Jeremy Clarkson school of thought and have probably never actually had much to do with the modern “euro3/4” diesel engined car. While no internal combustion engine can ever be considered green the diesel engine certainly has more going for it than the petrol engine in terms of overall pollution and when run on bio-diesel is relatively green. It should be remembered also that the smaller particulates are also produced by petrol engined cars but as they are not visible from the exhaust it is often assumed that petrol cars don’t produce any particulates but because you can actually see the larger,less harmfull,particulates from the exhaust of the diesel it is assumed that they must be more polluting. Their high torque at low revs and high gearing certainly makes them feel much better to drive than a similar sized petrol engined car and the fact that they also do about 33% more miles than the petrol car on the same amount of fuel and hold their value better can only be a bonus and prove that most people don’t hold the views of people on this forum.. 

 
 

 

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