Diesel: and if you wrong us?

[bham]

I went for a walk on the site indicated by abyssin3: http://forum.aceboard.net/recherche.php ... go=1Diesel: and I found this:
http://forum.aceboard.net/forum2.php?ru ... &login=879

what if we were cheated?
by Jean Louchet, INRIA (National Institute for Research in Automation and Computer Science)

The "official truth" about Diesel

Here are the statements we commonly hear:

* diesel consumes less
* diesel fuel is cheaper
* the efficiency of a diesel engine is higher than that of a gasoline engine
* The longevity of a diesel engine is greater than that of a gasoline engine
Now that all engines are equipped with catalytic converters and particulate filter diesels, toxic fumes are eliminated and only the CO2 remains.
* diesel pollutes less than gasoline
* diesel is better for the ozone layer
* diesel is better against the greenhouse effect.

Almost all of these claims are false, and none is completely correct. Unfortunately, as you will see, the serious sources of information on these topics are for the most part in English and have never been translated into French - which may be a good fit for some.

It is possible - and even probable - that I made some mistakes in the following: in fact I am neither chemist nor physicist of the atmosphere nor engineer engine, even if the English cooking, the lapping of valves and the profile Cams are quite familiar to me. Thank you for pointing this out, as well as the references (serious scientific articles) that could complement or give different points of view.

From the following analysis comes a conclusion: whether we are users of diesel engines or not, we are victims of propaganda dangerous for our health and for the planet.

Objective elements

benzopyrenes

In 1984 the Calspan company (Buffalo, Michigan) had shown that the concentration of Benzopyrenes in the outputs of passenger diesel engines was approximately 100 times higher than in heavy-duty diesel (and in negligible concentration in petrol engines). These benzotrucs are the main atmospheric agents responsible for cancers. Results never published in the scientific literature because emanating (we speak of fumes!) From work ordered internally by car manufacturers (VW in particular) and that I learned directly in 1984 because I knew by my job the engineers of Calspan who made the measurements.

It means in practice that a single diesel car pollutes (carcinogenically speaking) as much as thirty semi-trailers! Twenty years of silence later, furnished only by my small and vain gestures (it seems that I am sensitive) and, in the opposite direction, some great propaganda of PSA pointing to CO2 as the main pollutant (if it is true, therefore prohibit Perrier and Quézac!)

Reinforcement of allergenicity of pollens by diesel emissions

To add a layer (if we can say), here are some sites on this subject, provided by a German friend who told me that European standards in particles were exceeded in some German cities (we imagine in France so!), and that people were beginning to take legal action against the government on this issue.

Epidemiology

The magazine "Que Choisir" recently took the commercial risk of spreading a bit of the truth. I will summarize the article: diesel vehicle emissions caused, in French cities alone and in the year 2002, between 6450 and 9500 additional cases of death from cancer of the respiratory tract compared to what would have occurred if these same vehicles had run on gasoline. This brief article is actually a summary of the AFSSE report (see http://www.afsse.fr/documents/Rapport_1.pdf) made in 2004 at the request of the French government. The AFSSE report is much more detailed and interesting: it shows that diesel still causes far more deaths from cardiopulmonary diseases than just cancer of the respiratory tract. The total number of deaths due to fine particles in the atmosphere (so essentially diesel) is estimated 31700 dead 2000 in France (AFSSE report, page 60): compared to 30000 due to tobacco or 7000 approximately due to accidents of the road. And we must not forget that, while passive smoking exists (and fortunately has dropped since the Evin law), the vast majority of these 30000 are about smokers themselves and it is up to everyone to take responsibility; on the other hand, dieselism is more often passive than active (it seems to me!). Which means that diesel kills many more people than tobacco and road accidents combined!

We put deterrent labels on the cigarette packs, well. What are we waiting for to put on diesel pumps at petrol stations?

If nothing is changed, the prospects on the 2020 horizon are dire.

It is now established that the benzopyrene microparticles (precisely those that no filter can stop, of size less than about 10 microns) cross the pulmonary barrier and enter the bloodstream. We do not know all the organs where they can attach, but it is already established that the brain is one of the targets since we find these same diesel particles in the brains of laboratory mammals exposed to diesel fumes. These particles are believed to promote the development of brain tumors, but this is not currently proven.

I also saw an article on ovarian cancer due to diesel: women exposed to diesel emissions have a probability of developing ovarian cancer multiplied by 3,5 (International Journal of Cancer, Vol 111, Issue 2, August 2004 )

Nitrogen oxides NOx

The "pollution peaks" of large European cities are due to the exceeding of the maximum permitted concentrations of NOx. The current remedy used in France is to restrict movement or even do nothing at all. So who is producing NOx?

In a gasoline engine, the production of NOx is inherently low. On an engine built without special precautions, the product of the NOx and CO concentrations is approximately constant. A "richer" setting gives less NOx and more CO, a "lean" setting (lots of air and little gasoline) the reverse. The very questionable "pollution control" of the compulsory technical control fixes a maximum for the CO rate, but no minimum, which amounts to encouraging the production of NOx which varies in the opposite proportion. Catalyzed gasoline engines (triple effect catalysts, compulsory since 1991 I believe) have electronic richness control which keeps NOx production at a very low level. This electronic regulation is not possible on diesel engines whose NOx production always remains high despite the catalysts (double-acting only). In short, diesels remain the main source of NOx.

Response to official and publicity "truths"

"diesel consumes less"

IT DEPENDS. Less than what? liters of fuel? And why count in liters? Knowing that it takes more oil to make a liter of diesel than it does to make a liter of petrol, and that diesel is heavier than petrol ........

"diesel fuel is cheaper"
FALSE. Cheaper per liter, yes, public price in France in 2005. Much cheaper per kilogram, unfortunately yes (again in France in 2005), but this price difference is completely artificial. The taxation of fuels per liter (not per kilogram) is a tax device which makes it possible to charge less tax on diesel than on petrol ...........

"the efficiency of a diesel engine is higher than that of a gasoline engine"
IT DEPENDS. It would be more correct to say "equal or slightly higher".

In theory, the thermodynamic efficiency of an engine is linked to its volumetric ratio. The latter is between 10 and 11 on petrol engines, and around 25 on diesel engines. In theory, a diesel engine therefore has a higher efficiency (roughly half the thermodynamic losses). In reality things are more complicated and the total energy yields are much lower, due to multiple other losses, independent of the volumetric ratio which ultimately has a very minor impact on the yield.

A heavy-duty diesel engine has a high efficiency (around 30%). The internal combustion engines that have the highest efficiency are the diesel used in thermal power plants and in super-tankers and container ships. The world record is held by a Japanese-made engine, which achieves an energy efficiency of more than 50%. The maximum speed of this engine is 102 revolutions per minute, and each cylinder has a displacement of 1820 liters. The very low speed allows the combustion to be almost complete.

Diesel engines used in passenger cars and light commercial vehicles have a very different technology, which aims to have light engines and high horsepower per liter. This is done to the detriment of the quality of combustion and efficiency: in fact in a diesel, combustion is triggered spontaneously and the flame spreads slowly (unlike a spark ignition engine where the flame spreads almost instantaneously), this which does not mix well with engines whose camshafts are designed to be able to approach high speeds. For an engine (gasoline or diesel) to have a high maximum power, the exhaust valves must open as soon as possible, which means that on a diesel the discharged gases have not finished. burn. Particulate filters, which nevertheless allow the most dangerous particles to pass, do not help because they create a back pressure which opposes the evacuation of the burnt gases from the cylinder. Modern passenger cars thus have an efficiency of close to 25%. By comparison, modern naturally aspirated gasoline engines (with a compression ratio of around 11: 1) also have an efficiency close to 25%. Supercharged ("turbo") gasoline engines have lower efficiency because their compression ratio is lower.

In summary, a passenger diesel engine has roughly the same fuel efficiency as a non-turbo petrol engine.

"the longevity of a diesel engine is greater than that of a gasoline engine"
FALSE. Admittedly, heavy-duty diesel has a longer lifespan than the others. But if we confine ourselves to touring engines, the two longevity records are held by two petrol engines (a Volvo with 2,5 million km and a Mercedes with 1,5 million). It is true that the first diesel engines for French tourism had a long life because it was at the origin of utility engines. Currently, diesel being the workhorse of French manufacturers, French diesel lasts longer than French petrol, but the reverse is true almost everywhere else. A construction of the same quality (and therefore the same price) a gasoline engine will last longer.

"Now that all engines are fitted with catalytic converters and diesel particulate filters, toxic fumes are eliminated and only CO2 remains"
FALSE. A catalytic converter only works once it is hot. During the first quarter of an hour of operation, everything goes directly into the atmosphere. Once the catalyst is hot, it can completely burn unburnt gasoline engines (which are light hydrocarbons and CO) but does not remove either the NOx or the microparticles which are produced by diesel.

All particle filters stop about 90% of particles, but the 10% which pass are precisely the most dangerous (microparticles) because they cross the pulmonary barrier, pass into the blood and cause cancer even in organs distant from the lungs (in particular the brain) and diseases of other organs (ovaries, etc.). Being light, they remain suspended in the atmosphere for several days or weeks and travel very long distances.

"diesel pollutes less than gasoline"
FALSE. There is not ONE but several pollutants.
The only pollutant that diesel produces in smaller quantities than gasoline is carbon monoxide CO. It is a gas which is only toxic in the short term and at high concentrations (engine running in a closed garage, faulty bathroom water heater ...) but it very quickly transforms into CO2 (not toxic) in the atmosphere under the effect of UV and ambient oxygen.

CO2 (carbon dioxide) is not toxic - it is released in large quantities by natural human respiration and by my bottle of Champagne (or Perrier). We can only blame him for his contribution to the planetary greenhouse effect, but the question is not so simple and is still the subject of scientific and political debate. In any case, it is produced in equivalent quantity (to within 5%) by petrol and diesel engines (on condition of comparing touring engines of equivalent power).

All other pollutants - the "real" ones, those which are directly harmful to human health - are produced in much greater quantities by diesels and in practically nil quantities by gasoline engines.

"diesel is better for the ozone layer"
FALSE Diesel, even catalyzed, is the main producer of unburnt hydrocarbons (tars) and NOx. The diesel engine is more harmful to the ozone layer than the gasoline engine.

"diesel is better against the greenhouse effect."
NOT TRUE IF WE COMPARE WHAT IS COMPARABLE. CO2 production is roughly equivalent for equal power (see above, regarding CO2). Obviously a Polo diesel engine will produce less CO2 than a Jag petrol engine ... On the other hand, the production of NOx (also greenhouse gases) is much higher on a diesel. Diesel is therefore more harmful than gasoline in terms of the greenhouse effect.

Conclusion
Concrete policy measures have already been taken in some countries, notably in Japan, where all movement of diesel vehicles (even utility vehicles) is prohibited in the Tokyo Metropolitan Area. This ban is becoming widespread, and I was told that there is currently a major conversion of existing diesel vehicles into gasoline engines. I do not know if this operation is financially supported by the State.

Norway (a country with a low population density but where public opinion is aware of health problems and climate change) has sounded the alarm this year (2005) because the sale of diesel reaches 30% of total new cars: the Ministry of Transport estimates that the safety threshold is exceeded and the government is preparing highly dissuasive measures.

In Denmark, the proportion of diesel has remained low, following good information for consumers, and the presence of a special "diesel" tax of 8000 crowns (1100 Euros) per year and per vehicle.

In the United States, where the proportion of diesel-tourism is negligible, the federal government is preparing measures to limit pollution from heavy goods vehicles (which is however relatively lower on these large engines, see above). It is in the United States that the studies on the health effects of diesel are the most numerous and thorough, although it is probably the least affected among the developed countries.

In France, a country with a fairly high population density, 70% of new passenger car registrations are diesel, and no measure has been taken. Spain and Belgium are in similar situations.

Jean Louchet
http://fractales.inria.fr/~louchet/perso/diesel.html"

What do you think of all this? benzopyrenes and performance and longevity.

[iota]

Jacques Calvet from psa said it was not true I believe it!

[SixK]

One thing is certain, I much prefer to breathe what comes out of the exhaust of my R21 carburetor what comes out of my HDI.

And yet on HDI, there is no visible pollution ...
But when stopped, if the wind is contrary, there is quickly a smell of death ...

SixK

[bolt]

extract from: diesel engine ed. 1976:


use at partial load: better diesel output than petrol: can someone confirm? (with fuel consumption curves, gasoline, full load + partial loads)

use at zero load at idle: fewer droppings for diesel than petrol: same: can someone confirm with tests?

bolt

[pluesy]

I had for 6 years a bx sedan 1600 carbureted which I used quazi that in short trips (15 km) average consumption 10 / 11L per 100 ... in long trips (800km) 7L to 100

I replaced it with a 1.9 l diesel station wagon without turbo
in town 6L / 6.5Lau 100 on highway 5L / 100km

before I was spending 100 euros per month on fuel now I'm less than 50 euros ...

[Woodcutter]

I went for a walk on the site indicated by abyssin3: http://forum.aceboard.net/recherche.php ... go=1Diesel: and I found this:
http://forum.aceboard.net/forum2.php?ru ... &login=879
[...]

This quote extracted from personal pages has already turned here, in the spring I believe, it seems to me that it was Jean63 who found it ...

What else to say that this is an argument made by a convinced anti-diesel?
His argument is very clearly oriented, sometimes false ...
Furthermore, this gentleman seems to be one of those who still believe (who believed? In 2005 ...) that the responsibility for CO2 in increasing the greenhouse effect is still questionable and that the CO2 production by petrol is identical to diesel ... Truly amazing ...
By spending time there, I think that we can take point by point its "dismantling" as a rule of the diesel and answer it in many cases ... No time tonight ...


For the lowest consumption at partial load, it seems to me that it is linked to the pumping of a petrol engine which does not exist on a diesel (no gas control valve)

[Other]

Hello,

The efficiency of the diesel engine depends not only on the compression ratio, but also on the ratio between the volumes at the end and at the beginning of the combustion.

At equal compression a diesel engine would have a lower efficiency than that of an explosion engine.

At low load, the internal combustion engine is disadvantaged because of the lack of filling and the high pressure behind the throttle valve. (sometimes I wonder if we should not put the pappillon on the exhaust) we would have our automatic ERG.

On a diesel when we make a restriction on the air intake is a dirty filter, it gives off more heat in the cylinder head at full power (in my case the radiator does not provide, the temperature exceeds the set point of the calorstat me who thought it was the reactor restriction in the exhaust)

Andre

[I Citro]

Even today, in the show "les ptits boats" on france inter, Jean marc Jancovici said that the first source of pollution was agriculture in front of heaters, factories and far ahead of transport ... everything is fine, therefore !

One thing is certain, it is easier to act on transport (with large tax increases) because it is an essential sector of our economy and perfectly controlled ...

[elephant]

It is certain that with the telecom resources we currently have, provided we are a little less rushed and store a little more (bye-bye just-in-time) we could reduce transport by 10 to 20%, which would do the road safety business

[--Ex--]

Even today, in the show "les ptits boats" on france inter, Jean marc Jancovici said that the first source of pollution was agriculture in front of heaters, factories and far ahead of transport ... everything is fine, therefore !

One thing is certain, it is easier to act on transport (with large tax increases) because it is an essential sector of our economy and perfectly controlled ...

By comparing transport to agriculture, to heating ..., you mean that it is easier to take care of transport (therefore fuel ...) than fertilizers, insulating barracks ... .?

For insulation for example, I find that measures are not so difficult to implement.
There are already energy balances that go in this direction for an awareness and I imagine that changes will be expected within 1 to 2 years. People will try to have a better energy balance for their home and will insulate better. Finally I hope it will happen like this: