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Peter_XX
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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.? :)
@LUH3417 You are probably right about EA and their business. On the other hand, I presume manufacturers of BEVs also care about their business. Perhaps you should not trust anyone :).
I cannot comprehend why we did not have this discussion already a couple of years ago. The current hype about BEVs reminds me of a Danish fairy tale. https://en.wikipedia.org/wiki/The_Emperor%27s_New_Clothes
Yeah, subsidies and all kind of other incentives (e.g. free parking) are the main selling points for BEVs. Those of you who can log in on LinkedIn can have a look at this: https://www.linkedin.com/pulse/ghg-potential-hybrid-vehicles-critically-needed-under-kevin-f-brown/
I might have been a little sarcastic in some of my previous comments, so let me elaborate a little on "real" emission levels. There is, of course, nothing as a zero-emission vehicle of this kind. To state that, you would need better NOx instrumentation than what is available today for on-board measurements and you would also need to measure background concentrations simultaneously; potentially correcting for the background level. We do not have any traces of NOx emissions as second-by-second graphs in this case but it is likely that there are at least some spikes of NOx at levels above the detection limit of the instrument. However, these bursts are very short and if there is a small offset of the zero calibration (or small zero drift between calibration and test run), this (negative) offset could cancel out the mentioned spikes, yielding zero emissions as a result. The only firm conclusion we can make is that this car, and a couple of others, have very, very low NOx emissions. I would also like to conclude that one should not try to distinguish between cars when the emission level is below 20 mg/km. Any difference between cars at this level might be just due to measurement scatter. Nevertheless, cheers to Mercedes! At least they are among the better of the best ones. Finally, some additional sarcasm: Results like these are probably the worst possible catastrophe for environmentalist organizations. Their whole rationale for activism is based on that diesel cars are high emitters from hell. If there is no devil (in the detail... er... case) anymore, what will they fight against in the future? Presumably, they will just ignore data like these and continue on as if nothing happened. If car manufacturers drop diesel development and pull diesel cars from the market, they have eventually won this case. If so, I have to acknowledge their success.
@The Lurking Jerk First, I do not think that a lot of people read this site. Second, I think the diesel reputation is now on such a rock bottom line, that there is not likely any hope for a change here. Note that cities like Paris will ban diesel cars no matter how clean they are. Third, yes I agree with you and I am afraid that many will start shouting out for phase-out even more vigorously than before; just as a response to information like this article. People are not always rational.
Well, this was quite expected and in the pipeline... Modern diesel cars are now at a development state when emission levels approach zero (see more information below). The article does not say it explicitly but I suppose the DOC also has NOx storage capacity. Another interesting technology with similar potential as this catalyst would be a passive NOx adsorber (PNA). I kind of like the simplicity of this concept over the quite complicated control of a conventional NOx storage catalyst. Rumors say, however, that the PNA technology is not quite ready for production yet. Another technology under discussion is to have a second urea injection before the last SCR catalyst. This could allow fine-tuning of the urea injection in a way that the large urea nozzle before DFP/SCR may not quite achieve. I reckon that "overdosing" of urea at this stage is also an option but I suppose that the two-stage injection would be more precise and waste less urea, while at the same time would give lower NOx. Mercedes does not use this but perhaps it is something for the future. Consider the link below and one of the conclusions from ADAC in the study: "It found that a Mercedes C-Class 220d powered by a 2.0-litre turbocharged diesel engine emitted no traceable NOx." https://www.thisismoney.co.uk/money/cars/article-6733271/Are-diesel-cars-really-dirty-Tests-reveal-models-produce-zero-NOx-emissions.html Some explanation about ADAC and their testing from the article above: ADAC, which is similar to the AA in the UK but tests hundreds of vehicle every year at its laboratory in Landsberg on the outskirts of Munich, tested a range of diesel and petrol cars to compare the amount of harmful emissions produced during normal driving on the road.
If they say: "... a yield of 43.2 C%...", it must be clear that this is the carbon efficiency. Energy efficiency is not quite the same. Plant mass contains relatively little hydrogen, so for sure, most of the energy is in the carbon. Ethanol contains more hydrogen than the plant but this does not mean that energy efficiency is much higher than carbon efficiency, since a lot of the energy used in the process must come from the carbon in the plants, or from other sources, e.g. electricity. Most likely, the energy efficiency is lower and this would be the most interesting result to know. Another point is that the system boundaries are very important when you try to assess the total energy efficiency. For example, you might get a sizeable share of the energy left in by-products and one of the trickiest things is to credit for this stuff or find a way of expanding the system boundaries to take it into account. This, however, seems to have been beyond the scope of the study.
95 PS is a joke from a 1,6-liter engine. Anti-downsizing? The state-of-the-art level is 160 hp from a 1,6-liter engine with single-turbo. De-rating such an engine all the way down to 95 PS does not make much sense. A 3-cylinder 1.2-liter engine could do the same job with significantly lower fuel consumption. That engine would still be de-rated somewhat from the potential 120 PS level, which, of course, make sense, if this is the targeted power level.
I think this engine, despite improvements, lags slightly behind state-of-the-art European engines, albeit that it is developed and produced in Europe.
Pretty much expected that the NOx limit could be met. No surprise either that the cost would not escalate. The question is if the measures against cold start emissions will have any significant impact on street level emissions, simply because cold starts are rare for HD vehicles? If we would draw a parallel from this study to diesel-fuelled LD vehicles, it is likely that (the anticipated...) Euro 7 level could be met already today and a potential Euro 8 level in a few more years. It appears as we do not need EVs to reduce emissions.
Scania uses an ignition improver in the ethanol fuel to raise the cetane number. To reduce the necessary concentration of this (expensive) additive, the compression ratio is also higher than for normal diesel engines. I realized that this information was missing in the previous post.
@EP This is GDI, so getting the engine to start at low temperature is not such an issue it was with MPI (there is info on this in the literature). However, current GDI technology is, most likely, not good enough to get low PM/PN at cold starts at low ambient temperature. Ethanol with MPI was a disaster in that respect. The latest 500 bar DI should fix most of the mentioned problems but it remains to be seen how well it can be adapted to ethanol. Diesel engines running on ethanol with DI, such as Scania, start at a few seconds at -30 deg. C. They actually start much better than the corresponding engine on diesel fuel. But here we talk about "real" high-pressure injection. Some basics: DME is a fuel with extremely high cetane number, while the octane number is very low. Its octane number is actually too low to be measured in an octane test engine. The cetane number for DME is higher than for diesel fuel. It is an ideal fuel for a diesel engine. Consequently, you cannot run an otto engine on DME.
@gryf Wow, you can certainly do the math! Good help for those who cannot... At Alibaba, you get what you pay for. Audi would never buy batteries there. But you would, I suppose... Good for Audi that you are not their Purchase Manager.
@Lad Re. battery: 10 Ah at 48 V is not 10 kWh. An MHEV would hardly come with a 10 kWh battery. Re. the price: luxury is never cheap. Re. "hurt": it seems as the Audi brand was not hurt so bad by Dieselgate as VW.
But PM emissions during cold starts at low ambient temperature (lower than +25, as in the tests) might be much higher for ethanol than for gasoline. Not so important for California but definitely for Wisconsin.
In the aerospace industry, a lot of tough alloys are also used but they are expensive, difficult to process and have other drawbacks. I do not have sufficient knowledge in this field to say if there is really any breakthrough here. Recycling is, of course, a general advantage for aluminum over steel.
@Mahonj Well, you can find two answers in the article. Data on strength is clearly stated and since percentage (of doping particles) added most likely is very low, there will be little impact on density. Since this seems to be on-going research, with additional improvements in the pipeline, it is too early to address the two other questions.
I recall the year 2004 when Mercedes started mass production of FCVs.