DPF...Verständnisproblem...! Ungeeignete Krücke? (viel Text) | Posts 16+

Moreover, things will get even worse when Euro 5 comes into effect in 2010, which will likely mean the end for small and medium-sized diesel cars, because how can one possibly achieve the same level of nitrogen oxide emissions from a 2.0-liter TDI engine as from a comparable gasoline engine.


but finally, some good news

There is a highly efficient catalytic process for reducing NOx emissions in diesel exhaust, which is currently being tested in trucks: the urea catalyst.
This exhaust aftertreatment system does not require any additional energy , but it does require a reagent: a urea solution that is carried in a separate tank.

The actual NOx reduction process actually occurs with ammonia (NH3). However, since ammonia is considered too dangerous, a detour is taken via urea, which is a harmless substance that is then converted into ammonia within the catalytic converter.

The reaction in the catalytic converter can be simplified as follows:

6 NO2 + 8 NH3 -> 7 N2 + 12 H2O

Advantages of these methods:

-Engine efficiency and soot behavior can be optimized internally, regardless of NOx.

-no increase, but a decrease in consumption.

- Emergency aid is cheap.

-No AGR (Activated Regeneration) required.


Best regards,

Hi,
Great discussion! Thank you!

WarLord wrote:

Why shouldn't gasoline engines also produce soot?

"The gasoline engine also produces soot! And it produces quite a bit of it." You can see this beautifully in modern direct injection engines (FSI, GDI, etc.), although the soot particles are not as clumpy as in diesel engines.

Albrecht wrote:

Hello Bertil and the others, Regarding your explanation, I must say: it is unfortunately incorrect...

That's why I asked for a correction.
I'm just wondering which scientific publication (see my source) is the correct one...
I may be oversimplifying the filter mechanism, but I don't believe I can produce an "ideal laboratory filter" that would last for 250,000 km or more under automotive conditions. Theoretically, the conversion of soot/particles into CO2 is possible without major problems, but the varying environmental conditions make me doubt the feasibility of a long-term solution.

Albrecht wrote:

Therefore, no toxic substances or tiny, invisible particles are created!

I see things differently. During the regeneration phase, the soot is heated to 500-600°C, which inevitably leads to the formation of dioxins (this has already been documented).

Why shouldn't gasoline engines also produce soot?
'The gasoline engine also produces soot! And it produces quite a bit of it.' You can see this beautifully in modern direct injection engines (FSI, GDI, etc.), although the soot particles are not as clumpy as in diesel engines.


That would mean, according to the statements of some experts, that gasoline engines are even more carcinogenic than diesel engines. Has anyone ever considered that?

Best regards, WarLord.

WarLord wrote:

That would mean, according to the statements of some experts, that gasoline engines are even more carcinogenic than diesel engines. Has anyone ever considered that?

Benzene are even considered to be extremely carcinogenic.

As long as there is sulfur in the fuels (even in very small amounts), soot will be produced. Gasoline direct injection (DI) engines only function with sulfur-containing fuel. ...why is that?
Sulfur-free fossil fuels are likely to remain a pipe dream.

Throughout all these considerations, we have always assumed the use of an ideal fuel. That doesn't exist!

SeatArosa1.7SDI wrote:

Quote: Moreover, things will get much worse when Euro 5 comes into effect in 2010. This will likely mean the end for small and medium-sized diesel cars, because how can one possibly achieve the same level of nitrogen oxide emissions from a 2.0-liter TDI engine as from a comparable gasoline engine? but finally, some good news There is a highly efficient catalytic process for reducing NOx emissions in diesel exhaust, which is currently being tested in trucks: the urea catalyst. This exhaust aftertreatment system does not require any additional energy , but it does require a reagent: a urea solution that is carried in a separate tank. The actual NOx reduction process actually occurs with ammonia (NH3). However, since ammonia is considered too dangerous, a detour is taken via urea, which is a harmless substance that is then converted into ammonia within the catalytic converter. The reaction in the catalytic converter can be simplified as follows: 6 NO2 + 8 NH3 -> 7 N2 + 12 H2O Advantages of these methods: -Engine efficiency and soot behavior can be optimized internally, regardless of NOx. -no increase, but a decrease in consumption. - Emergency aid is cheap. -No AGR (Activated Regeneration) required. Regards

The urea tank can then be refilled by anyone, and if it doesn't work out sometimes, you just have to quickly crack open a wheat beer .
Sorry, I was just out drinking with my girlfriend.

Hello Bertil,

Quote:

I'm just wondering which scientific paper (see my source) is the correct one...

So, regarding that, I can assure you that what I wrote above is correct . A DPF filter that would function as you described initially (sources) would become completely clogged very quickly (unfortunately, I don't have time to read everything thoroughly).
While I won't completely deny that other substances besides CO2 are produced during the combustion of accumulated soot, the soot only burns at temperatures above 550°C. At lower temperatures, it doesn't combust without the aid of coated filters (e.g., BMW) or additives (Peugeot, VW). You can imagine it like a brick under the car.

From my perspective, the car manufacturers aren't installing the filters due to cost considerations, especially since many vehicles now meet the EU4 standard through combustion engine development. Peugeot probably wouldn't even have been able to produce an EU3 engine back then. They turned a necessity into a virtue and introduced the DPF.
The extra cost of a DPF is outrageous for every buyer.

I can also confirm that modern gasoline direct injection (DI) engines (like FSI, etc.) can produce a significant amount of soot.
However, soot is not considered in any standard for internal combustion engines.

Soot and ash are completely different things. Ash is a non-combustible residue that deposits in the DPF in the same way as soot, and remains there even during regeneration. Therefore, the filter also needs to be replaced periodically.
The SINoX catalyst is certainly an interesting development that deserves further attention.

Best regards,
Albrecht.

Albrecht wrote:

Hello Bertil, Quote: I'm just wondering which scientific paper (see my source) is the correct one... So, regarding that, I can assure you that what I wrote above is correct .

They don't contradict each other. It's probably also a matter of perspective.

Quote:

A DPF filter that would function as you described initially (sources) would become completely clogged very quickly (unfortunately, I don't have time to read everything thoroughly).

I've greatly simplified this to get a basic understanding. The 100µm filter size you mentioned as a mechanical filter is also stated there. However, it's said that these filters can only filter out particles up to a size of 5-3µm. And it's especially the smaller particles that pose a problem for the lungs.

Quote:

I will not completely deny that other substances besides CO2 are produced during the combustion of accumulated soot.

I see that as critical. Not that we have eliminated soot, but then we would have another problem that requires another catalytic converter/filter.

Pollutants that don't actually exist are still the best, and using the DPF as a crutch when there are other ways to do it, I consider to be wrong (see below).

Quote:

... From my perspective, the car manufacturers are not installing the filter for cost reasons, especially since many vehicles now meet the EU4 standard through combustion engine development.

Certainly, that's also a reason. Currently, there's no obligation to install a DPF, and the EU4 standard can be easily met without it. VW even assumes that the EU5 standard will not be met.
Just 5 years ago, the EU4 standard was considered unattainable for small diesel engines... how wrong that was.

Quote:

Peugeot probably wouldn't even have been able to put an EU3 engine in those cars back then. They turned a necessity into a virtue and introduced the DPF. The extra cost of a DPF is outrageous for every buyer.

Okay, the first FAP engine was a pure EU2 engine.

Quote:

... However, soot is not considered in any standard for internal combustion engines.

Unfortunately, but for now, the "bad" diesel is to blame...

That would mean, according to the statements of some experts, that gasoline engines are even more carcinogenic than diesel engines. Has anyone ever considered that?


Benzene are even considered to be extremely carcinogenic.

As long as there is sulfur in the fuels (even in very small amounts), soot will be produced. Gasoline direct injection (DI) engines only function with sulfur-containing fuel. ...why is that?
Sulfur-free fossil fuels are likely to remain a pipe dream.

Throughout all these considerations, we have always assumed the use of an ideal fuel. That one doesn't exist!

I understand that benzene is considered extremely carcinogenic (although, as far as I know, it mainly affects refueling). But, is the sulfur in gasoline really the only culprit behind the soot problem? I think, if I understand correctly, even a gasoline engine should produce soot, even when using sulfur-free fuel, right?

Best regards, WarLord.

WarLord wrote:

I think, if I understand everything correctly, a gasoline engine, even when using sulfur-free fuel, should still produce soot, right?

Yes, that's right.

The current fuel is only low in sulfur. Sulfur is the largest contributor to emissions in fuel, but it also acts as a lubricant to some extent.

Hello Bertil,

Quote:

I have greatly simplified this to get a basic understanding. The 100µm filter size you mentioned as a mechanical filter is also stated there. However, it is said that these filters can only filter out particles up to a size of 5-3µm. And it's the smaller particles that pose a problem for the lungs.

Without wanting to sound like a know-it-all, you haven't simplified it, but rather you've misunderstood it. Please refer to the diagram in the Word document I've attached for clarification. Even the smallest particles are separated with a very high percentage.
When soot is reduced through internal combustion processes, it leads to a shift towards very small particles that can reach the lungs. The emission standard is still met because the measurement is mass-based, and the very fine particles are not captured on the filter paper or weigh virtually nothing.
From an environmental perspective, the filter (e.g., made of...) Do not blame the silicon carbide.
Something else is the system that is currently distributed by TwinTech and ATU. That's Vera... (followed by something that's been cut off).

Best regards,
Albrecht.

Here are some facts, as there has been a lot of speculation already.

Here's the translation:

'It's a filter, which means it needs to be cleaned – either with additives or through thermal regeneration. This only works as long as there are no substances trapped in the filter that cannot be cleaned and will therefore burn. This means: if you use poor-quality diesel or oil that forms solid ash, it will quickly become clogged.' The exhaust pressure increases, and so does the fuel consumption. If you don't replace the filter, the car will eventually stop running.
'Even with a functioning filter, the exhaust back pressure is already quite high, at least several hundred millibars. This increases fuel consumption. The reason why diesel filter engines don't consume significantly more fuel is that current TDI engines are designed for emissions optimization, not fuel efficiency. This is also why well-tuned TDI engines often demonstrate a fuel efficiency advantage.' It's no secret that, as a reward for using the filter, you can allow the engines to run at their optimal consumption levels again, while still remaining below the emission limits.

Assuming that a single vehicle now emits as much soot as 1000 diesel vehicles equipped with filters, but that it costs a good million euros (1000 euros per vehicle) to achieve this, one realizes just how much nonsense is being imposed on us. If it were truly worth one million [currency unit] to the economy to save the soot from a single truck, then those trucks simply wouldn't exist anymore.
Manufacturers who, for understandable reasons, tried to avoid the filter craze were ultimately forced to comply by so-called 'experts' (ADAC).
(Where did the ADAC point out the disadvantages?) Not everything that is technically feasible is also sensible.


If our politicians were truly serious about reducing greenhouse gases like CO2, they would need to subsidize diesel fuel. Instead, the price of diesel engines is being increased to the point where they will soon only be available in mid-range vehicles and above. (See here in the forum).

What a stir there was when the Green Party proposed increasing the price of gasoline to 5 Deutsche Marks. (And only taking one vacation every three years!)
Has anyone noticed that we've already exceeded the 2.50 DM mark?

@ Bertil: You are right about the benzenes; the benzenes adhering to the soot are also the main cause of the carcinogenic effect of diesel soot. This is unlikely to occur with plants or gas-powered appliances.
The problem is that the studies on diesel soot that I am familiar with were conducted at concentrations where flour dust would be lethal. Despite being a highly dangerous substance, it is readily available for purchase in every grocery store.

I'm not familiar with the sulfur issue. As far as I know, it was removed because it poisons the diesel catalytic converters, or in the case of gasoline engines, the analog lambda sensors (which provide an analog signal corresponding to the oxygen content, unlike the step function of standard sensors).
EU4 cars still have NOx sensors that can also be damaged by sulfur.
I recommend that everyone finds out how much exhaust sensors cost for a gasoline direct injection engine BEFORE they buy one. Eventually, you might find mass airflow sensors or throttle position sensors really cheap.

Albrecht wrote:

...without wanting to sound like a know-it-all here...

Hello Albrecht,

After the head teacher , I had asked! Otherwise, I probably wouldn't have written the comprehension test. You've just completely changed my perspective on things.

I reviewed a specification for a Diesel Particulate Filter (DPF), and it stated under "Efficiency": Particles larger than 5µm. The DPF cannot retain particles smaller than this size. However, particles smaller than 0.1µm are known to be inhalable and dangerous to the lungs. Therefore, the DPF (Diesel Particulate Filter) is not a factor when considering particles that reach the lungs.
Furthermore, the regeneration process was described, and it mentioned ash particles (less than 5µm) and CO2. The origin of this ash was attributed to fuel impurities and oil residues from the combustion process. Everything comes in great, engine-friendly sizes, and also includes an engine without a DPF!

@garth.brooks

Sulfur not only poisons the sensors, but also damages the special catalytic converters in direct-injection gasoline engines.

TDI engines produce significantly more particulate matter in the USA compared to the EU. In Germany, diesel fuel can contain a maximum of 50 ppm of sulfur, while in the United States, it currently contains 1500 ppm (which is now being reduced to 300 ppm).