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Peter_XX
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I am a little ambiguous when I see development like this. It is good with PM/PN reduction in general, but still, a GPF is the best solution if you strive for low levels under all operating conditions. When we compare with a diesel car, it can have 90-99% lower PN emissions than a GDI car without a filter. For those of you who are interested, please have a look at the article in the link. (I presume those of you who are not fluent in German can get it translated.) The study shows that the particulate level in the tailpipe from a diesel car can be lower than in ambient air, i.e. the car cleans the air. This is kind of setting the standard for low emissions, even in comparison with an EV, which cannot clean the air. A gasoline car with high-pressure injection but without GPF cannot compete. Unfortunately, the low PN level of diesel cars is not noted by media (other than ams). In the industry, the low PN level for diesel cars is a well-known fact but they do not talk about it. Thus, they will never ever get credit for it. https://www.auto-motor-und-sport.de/tech-zukunft/werkstatt/dieselabgase-partikelmessungen-im-realbetrieb/
Can we sense that there is a competition between methanol and LNG as "clean" fuels in shipping? There is, of course, no doubt about the preferences by Methanex Corporation in this case.
Perhaps 800 volt is more complex than 48 volt. And more expensive.
@Lad ICE killer? Ha, ha.... What are 30,000 reservations compared to the worldwide market for ICEs? Will everybody drive Porsches and Teslas in the future? I do not think that...
Tesla killer or just a small headache for Tesla?
After a thorough reading of the article, I saw that the quote: "Modern diesel engines emit less CO2 than gasoline engines because diesel fuel has a higher energy density..." is wrong. Moreover, I think they should define what they mean with "energy density", simply because it could be interpreted in several ways. VW should check such statements better.
This technology has been in discussion for some time now and VW has actually hinted about that this has been in the pipeline. It is simple to conclude that the NOx emission from diesel cars is no longer a real problem. Recall that SCR technology is relatively new in this vehicle type and progress is usually fastest after the introduction. Thus, it is no surprise that we now can observe just this. The German ams magazine recently tested a Mercedes diesel car and got a PN level 25000 times lower than the limit. The next issue of the magazine will cover diesel emissions and presumably, will focus on just this topic. Now, we should realize that we cannot tell if the PN level is, e.g. 25000, 10000 or 1000 times below the limit. Current PN instruments simply are not good enough to measure such low levels. We can only say that the PN level is far, far below the limit and, in many cases, also significantly lower than ambient air levels. The car acts as an air cleaner. Regarding CO2, one should note that CO2 is measured in the exhaust. There is no need to speculate about carbon (CO2) levels in the fuel in the tank. This is already taken into account on the regulation by measuring in the tailpipe. (Upstream emissions should, of course, be considered in a well-to-wheel analysis.) Diesel engines are more efficient than gasoline engines. This results in lower CO2. For comparable gasoline and diesel cars, the difference is about 20%. Since density for diesel fuel is higher than gasoline, the difference in volumetric fuel consumption is around 30%. If we look at CO2 per energy unit, the difference is (again) roughly similar to the mentioned 20% for CO2. The difference in fuel mass used is also around 20%, for the same reasons as above. Since the diesel cycle is the most efficient thermodynamic cycle ever invented, it would be a great mistake to forbid, or by other means, try to ban this technology. In the foreseeable future, the use of fossil fuels will still be used and during this period we should do our utmost to reduce CO2 and energy use. Currently, the diesel engine has very bad publicity but it would deserve some credit for recent progress. If there is a diminishing market, manufacturers will not spend resources on its future development.
The average diesel car is about 20% better than the average gasoline car regarding tailpipe CO2; if we compare cars of similar size. If we compare a small gasoline car with a big diesel SUV, the latter would, of course, be worse, but I presume apples-to-apples comparisons is what is of main interest here. Then, some people also drive big gasoline SUVs and we all know how clever that is.
If nobody cared to read the MTZ article, any attempt to a meaningful discussion on this topic would be pointless.
Anybody who read the MTZ article? Or do you prefer to post crap?
I recommend those who are interested to read the article in MTZ Worldwide. There are also some other articles on the same topic.
Large marine methane-fuelled engines have used this technology for ages. It makes sense in that case since the spark plug is very small compared to the combustion chamber. Igniting a very lean charge in such engines is challenging. Scaling spark gap and voltage according to the size of the engine is simply not possible. Recent F1 technology is, per definition, very much confidential but they also seem to find advantages with a pre-chamber. I suppose the researchers, in this case, aim to stretch lean-burn technology as far as they possibly can also on passenger car engines. Why not? With a few exceptions, there has been relatively little research in this field so far. It would be interesting to see the potential of this concept. I could add that urea-SCR aftertreatment technology borrowed from diesel engines could be used to cut NOx under conditions where engine-out NOx would be too high for NOx storage catalysts. SCR aftertreatment is also tested in some EU projects on lean-burn gasoline engines. Cost and complexity are issues but we know today that SCR aftertreatment on diesel engines can be very effective, so of course, it could be used on other types of engines as well. Note that high NOx has been a prohibitive problem for many lean-burn concepts in the past. Conventional TWC is so much easier and cheaper but it can only be used on lean-burn engines when they run stoichiometrically or with fuel enrichment. Mahonj must learn to distinguish between research projects and a commercial product. This study must be very far from commercialization and it might be difficult to assess the full potential.
I guess Tesla is the same crap when it comes to quality as any other American car.
The problem with MeOH is the negative standpoint from the auto industry. A couple of years ago, the automotive manufacturer's organisation (known as the “Organisation Internationale des Constructeurs d’Automobiles”, or OICA) agreed on a document called "Worldwide Fuel Charter" (WWFC) for fuel specifications. WWFC has a clear position on MeOH. This mainly concerns MeOH as a blending component but the message is quite clear: "Methanol is not permitted". OICA is the highest level organization for automotive manufacturers. Some manufacturers might have their own (different) position on MeOH but as long as OICA does not permit MeOH, not much will happen. Today, MeOH is the biggest chemical commodity in the worldwide market (fuels as gasoline and diesel are not considered in this case). Trade and transport of MeOH is worldwide. We also know how to distribute methanol and dispense it at refueling stations. There is no obstacle regarding the supply chain to utilize MeOH in vehicles today. Current vehicle and engine technology could be adapted to MeOH. In fact, MeOH has several advantages over gasoline and diesel, and in the future, fuel cells could be used. Moreover, compared to most other alternative fuels, MeOH from NG is quite affordable. Yet, it is not utilized. Perhaps someone at this site could ask OICA why not.
Methanol is already used as fuel for ships, e.g. by Stena Line in Sweden. I think the problem mostly is about cost. Using a scrubber and dirty bunker oil is still cheaper than alternative fuels. There is also an LNG ferry in operation between Sweden and Finland. (You can probably find many other examples in both cases on an international level.) Which option is better? Well, I suppose it depends on the supply chain. Both MeOH and LNG are made in large quantities today from remote natural gas. In both cases, cost and efficiency are some of the main issues. LNG can apparently be handled on ships without any major issues but it is not that practical on smaller vehicles/vessels. MeOH has an advantage here. On-board reforming of MeOH to make hydrogen is also simpler on a long-term horizon when (?) fuel cells would be an option. Would synthesis of MeOH from CO2 via energy supply from other sources tip the balance over to MeOH? Well, it remains to be seen... The problem so far seems to be that the automotive industry is not in favour of MeOH. Not at all! If this negative association is not broken, there is no future for MeOH in the automotive industry. LNG is already in use in HD vehicles, in spite of the problems associated with the handling of a cryogenic fuel in vehicles. https://www.stenaline.com/corporate/environment/supergreen-en https://www.vikingline.com/environment/lng/
Well, while one can embrace the progress it should still be noted that PN emissions from diesel vehicles are already lower than from any other type with ICE vehicle and tailpipe PN concentrations are mostly lower than ambient levels in densely populated cities. Therefore, future focus on PN should be on other engines/fuels. Moreover, it would be easy to achieve similar incremental improvements simply by improving DPF technology, albeit that there is no driving force for such improvement at the moment. @Scott Less soot might actually decrease DPF filtration efficiency, which could counterweight less frequent DPF regeneration. I am not saying that less soot production has to be negative but the interaction between engine-aftertreatment hardware and fuel is complex. As a side note, I could mention that filtration efficiency is far less for a GPF than a DPF. Thus, while the engine-out PN emissions for a GDI is lower than for a DI diesel, tailpipe PN emissions are higher for a GDI. GPFs tend to "self-generate" very frequently. A lower (average) soot loading decreases filtration efficiency substantially. @Lad Much to your regret, I presume, recent news (i.e. for about the past year) on diesel emissions has been very positive.
There is technology available to reduce hydrogen sulfide. It is routine in plants where biogas is upgraded to a quality similar to natural gas. It is not much of a technology challenge, just an incremental cost. Somewhat beyond the article, I wonder why biogas is not used to replace natural gas in power plants. This would be much easier than trying to make an automotive fuel of biogas (gaseous or liquid). A large marine diesel engine is rather tolerant of fuel quality and requires less fuel upgrade than automotive engines. (Gas turbines are not that picky either but they are normally too big for a biogas plant and small gas turbines are not as efficient as diesel engines.) For example, you have some CO2 in the raw biogas. This implies charge dilution, just as EGR and excess air. Large marine engines operate at high levels of excess air and also have a high tolerance for EGR and CO2. It is just a matter of engine control to use a "less upgraded" biogas. Moreover, you would also utilize all kind of waste heat and obtain a total efficiency of over 90% (which cannot be utilized to such extent in a vehicle, albeit that some waste energy can be used for cabin heating. This is no rocket science since you a container with such an engine is commercial today. Moreover, dual fuel and single (gaseous) fuel versions of such engines have been available for many years and the gen-set has similar electric efficiency (we are talking close to 50% here) as the corresponding (single fuel) diesel engine.
BEVs and PHEVs are much heavier than conventional ICEs, so this increases PM from road and tire contact. It is roughly a linear relationship. Asphalt contains PAH and other heavy hydrocarbons, so it is definitely a health hazard. Tires also used to contain PAH but I am not updated on to what extent this has been phased out from tires on an international level. PM from road/tire contact is definitely not inert and some studies even suggest it is more potent than exhaust PM. Cities close to the sea take salt contribution into account in evaluating their PM values, so salt is not an issue. Note that cars with ICEs can also clean dirty city air. I have done measurements on my diesel car under various driving conditions and got an average level of 2 ug/m3 (
Return of the dinosaur? If you look at state-of-the-art for a 4-cylinder 2-liter engine, it puts out 245 (or 240 in some cases) hp and 500 Nm of torque. This is achieved with the (nowadays) more or less mainstream twin-turbo system. No need for any electric mumbo jumbo in the air handling system. It is a no-brainer to imagine that you could use two such banks and get 480-490 hp and 1000 Nm (albeit you would not need 4 turbos). You have to assess the progress of the Audi engine vs. this benchmark. Thus, I am not as impressed as some of the posters on this site. Of course, it has higher efficiency than a gasoline engine. Not only at full load but the relative difference will be much bigger at lower load. It uses the diesel cycle. Nobody has yet invented a more efficient thermal cycle. (Albeit, you could argue that using Atkinson/Miller variants of the diesel cycle would be more efficient, but the base would still be the diesel cycle.)
I was about to say that this is quite similar to something (Valvetronic) that BMW has had for over 15 years but a quick check with Wikipedia tells me that it was first introduced already in 2001. I am not saying that this is worse or better than Valvetronic; I just conclude that the gain is approximately similar. There are also some cam switching solutions with lower cost and complexity but with smaller gains. Over the years, I have always wondered why fully variable valve timing, or so-called free valves has not gained more attention. Presumably, BMW has had a strong patent but this should have expired or will expire shortly. If you broaden the view somewhat, you realize that a feature like this could also be used on diesel engines. To my knowledge, cam shifting is being used on some diesel engines in production today but no one has yet introduced fully variable valvetrain on a diesel engine. You could argue that there is not much gain by reducing pumping losses in a diesel engine, which normally do not need throttling for power control as a gasoline engine but you could get a better combination of internal and external EGR and thereby gain FC. To simplify, it sometimes "costs" to increase external (short-route) EGR flow, since this requires intake throttling or, e.g., necessitates a non-optimal setting of the variable nozzle turbine. This eventually manifests itself in increased pumping losses. By optimizing internal and external EGR you also gain better control of the in-cylinder temperature. You probably only need long-route EGR, with associated simplifications and offset of the cost penalty by more complicated valvetrain. Moreover, you could increase the exhaust temperature and temperatures in the aftertreatment system without FC penalty, with a most welcome reduction of exhaust emissions as a side effect. There are some research papers that show potential benefits here but, as in the gasoline case, adoption of the technology seems slow.
So they deliver more than they produce...
@GasperG This will cost less than Toyota's hybrid system. Definitely! Why should there be no room for an intermediate solution on the cost-benefit scale? Where did you get the idea that this is a "3rd party solution"? Continental is one of the biggest suppliers to the automotive industry. They are definitely a Tier 1 supplier to the industry. For sure, they are developing this together with a couple of car manufacturers, like all other vehicle components. Oftentimes these days, development is actually initiated by the suppliers, not by the car manufacturers.
Well, correction: in many cases, you would rather prefer to put the driver - not the car - on a ketogenic diet.
@yoatmon Not quite correct. Some emission components are relatively short-lived.
Ketones? Right? Put the car on an LCHF diet.? :)