This is Peter_XX's Typepad Profile.
Join Typepad and start following Peter_XX's activity
Join Now!
Already a member? Sign In
Recent Activity
The authors talk about "industrial exhaust". If we think about automotive applications of this technology, urea would have to be hydrolyzed to ammonia, so to say, "offline" with respect to the aftertreatment system. It cannot be done at this low temperature on an SCR catalyst. However, there is technology for this available, where a heated catalyst makes ammonia from urea and this ammonia is injected before the SCR catalyst.
@SJC Why didn't you put in a full quote from the source you cite? It says: "...However, if one includes the thermal efficiency for the methanol synthesis process from natural gas (~60%), then the overall energy efficiency (natural gas to gasoline) is about 50-60%." Even if I have seen higher numbers for efficiency from natural gas to methanol, the total efficiency is still very low.
I agree with KokomoKid1, series hybrid systems tend to be less efficient than parallel hybrid systems, particularly on highway. Toyota's THS is kind of a mix between series and parallel using the power-split. It sacrifices a little highway efficiency compared to an "ideal" system. In any case, it sets the current standard for fuel efficiency. I wonder how noice will be perceived (albeit if it is quiet) when there is not much connection between engine operation and power demand. For example, if the engine is running at high power during vehicle standstill.
Without ammonia for fertilizer, we could not feed billions of people on the planet.
@SJC Yeah, but if you already have methanol you can use that in your car or blend it in gasoline. They already do that in China. Or, at least did..., the last time I visited China.
Well, I came into the discussion on this topic rather late. I reckon that there is a significant potential for hyperexpansion. Sure! However, most mechanisms proposed so far to utilize this potential tend to become very bulky and complicated. Here we see another such example. One should also note that there already is an engine that uses a high expansion ratio and high charge pressure. This is the diesel engine. As indicated, the maximum cylinder pressure for a diesel engine is rather high in comparison to an otto engine. Millerization, which is also an option to utilize hyperexpansion, could be used on a diesel engine (as well as on an otto engine), which reduces the max pressure and/or further improves efficiency. The authors promise a 20% reduction in fuel consumption. Well, this is also what a diesel engine can provide and they aim on a moving target. So, by the end of the day, it boils down to if they can make this engine less complex and cheaper to manufacture than a diesel engine.
Well, this is a competition for prize money, so we will see which solution wins. The ultimate solution might be ceramic but the question is if the mechanical properties are sufficient. Already as a young engineer a couple of decades ago, I held such turbine parts in my hands but they never got mature for production. Re. transient response: Ask a driver and he/she will answer: more! We have all heard about the excellent transient response from Audi's e-booster on this site but I recently saw a magazine that compared to a conventional twin-turbo car from another german manufacturer and the latter was considered better regarding transient response.
Well, this site might soon get an overflow of angry comments regarding combining the words "Eco" and "Diesel" to "EcoDiesel" :). Those who look for progress in technology might note the use of low-pressure EGR. This is now state-of-the-art technology but still not used on all engines.
After all the criticism they made about EU legislation, couldn't they come up with something better?
Well, we also heard "Fuel and Technology neutral emission limits" from the EU; and others. Nothing new here either.
Very disappointing! During the last couple of years, everybody seems to complain about how the EU and its authorities have handled emission limits and regulations. Then, you would think that if those who complain the most would come up with their own proposal, it would be much better. However, this is no better. It is worse… much worse! A proposal must be concrete. Lots of empty phrases are of no value. Let me make an analogy from sports: I presume you can all distinguish between a professional runner and a “hobby-jogger”. This is a proposal (for new emission regulations) by the hobby-jogger. There is hardly any point in commenting on details in the proposal. As said initially, very disappointing.
Well, a gasoline engine can improve from, let's say 37% to 45% efficiency. What if you start with an electric motor at 97% efficiency? If we do not bother about relative and absolute percentages here, would we expect an electric motor to reach 105% efficiency with further development? No! We all have some feelings about the laws of nature to understand that this is not possible. Considering current (average) electricity production in the EU, the Ricardo engine would have lower CO2 emissions than a corresponding EV. So, why would we stop developing ICEs?
So, by the end of 2019, Volvo should have electrified all new car models. Does this mean that we should wait for wonderful things to happen before the end of this year?
@Justin, I do not need comments from a clown like you. It is obvious that the current US administration does not accept current evidence on climate change. Sad!
However,... Americans don't believe in climate change. Fake news!
You can reuse CO2 with a methanol fuel cell vehicle. CO2 produced by the FC/reformer can be stored in the methanol tank using a bladder to separate methanol and CO2. CO2 will be stored under pressure at liquid state. At the refueling station, methanol is dispensed and CO2 is returned to the station.
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.
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.