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Peter_XX
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So, they brag that they can meet Stage V without aftertreatment. Fine. I just wonder if car manufacturers also will start bragging about that they can meet Euro 6d-TEMP without GPF on their gasoline cars. This limit was enforced from September 1 this year in the EU but I have not yet seen anyone point out clearly that they do NOT use GPF.
Newer trucks have particle filters, so this is not a problem on those trucks. It seems easy to forget such simple facts. The tailpipe PM/PN level from new diesel trucks can be lower than from vehicles using so-called "clean fuels". Oftentimes, the level is also lower than in ambient air in densely populated cities.
@Lad These engines can have cleaner exhaust than ambient air. For example, PM is "zero" in the diesel case. NMHC is also certified as "zero" for the diesel engine. Running this engine will clean the air from PM emissions. This is something electric vehicles never can do. @Carl I recognize your point that GHG emissions are higher for the ROUSH propane engine. This is usually the case when you compare engines using "otto" and "diesel" cycles, even if the fuel for the otto engine (propane) contain less carbon per unit of energy. Moreover, 90% cleaner than the standard does not necessarily mean 90% cleaner than the corresponding diesel engine, as the data you cite show. We know that recent advance in diesel aftertreatment very soon could enable meeting the future 0,02 g/bhp-hr limit (you need a certain margin to the limit value, so this means certifying at ~0.01 g/bhp-hr). However, I would not anticipate that engine manufacturers will apply such technology in the near future on diesel engines; not even on selected engine families, simply because this would put pressure on all engines to fulfil stricter standards. Consequently, on paper, it looks that the propane engine for the moment would have a significant advantage regarding NOx emissions (but disadvantages for all other emission compounds...) in the near future but this advantage is smaller than the "true" advantage from a technical viewpoint. If the best available technology would be applied in both cases, as a technology-neutral approach would require, the difference would diminish. Finally, both engines are so clean that all talk about the need for electrified vehicles can be dismissed.
Only a very, very small fraction of PM2.5 does come from the tailpipe of vehicles. Tailpipe particles are far smaller than one micron (thus, they might have other health effects, but I will leave that topic for now...). The main contribution to PM2.5 and PM10 from traffic is from tyre/road contact. These PM emissions are roughly proportional to vehicle weight. If you replace ICEs with battery vehicles, you will increase PM2.5 and PM10 emissions. This is a very simple fact that gets neglected all the time.
@E-P One problem with H2/CO mixtures is the low density. Thus, port injection (if one can accept the denotation of ”injection” of a fuel in gaseous state) has the drawback of low volumetric efficiency. Consequently, previous concepts have not achieved the full potential regarding fuel efficiency. I would envision using a reformer that produces the H2/CO mixture at high pressure so that direct injection could be used. This would enable high volumetric efficiency and low pumping work. However, I am not aware of any such research for the moment but it should not be impossible, since reformers can operate at elevated pressure.
@E-P One problem with H2/CO mixtures is the low density. Thus, port injection (if one can accept the denotation of ”injection” of a fuel in gaseous state) has the drawback of low volumetric efficiency. Consequently, previous concepts have not achieved the full potential regarding fuel efficiency. I would envision using a reformer that produces the H2/CO mixture at high pressure so that direct injection could be used. This would enable high volumetric efficiency and low pumping work. However, I am not aware of any such research for the moment but it should not be impossible, since reformers can operate at elevated pressure.
In a refinery where high yield of gasoline is the objective, there is a surplus of hydrogen, even though some of it is used for hydrogenation and desulfurization. However, in European refineries, where high yield of diesel fuel is the objective, there is lack of hydrogen. As correctly mentioned by gryf, this hydrogen is mostly made from methane but this is from fossil CNG/LNG, so there would be some scope of replacing this hydrogen. Efficiency in a Btl refinery could be greatly increased if hydrogen from another source would be available. Interesting to find that work on DME/MeOH is conducted: http://www.greencarcongress.com/2018/08/20180814-meohdme.html
This concept was a well-known in Sweden already at least 15 years ago from work by Chemrec and others. If you synthetize "hydrogen-rich" fuels, such as e.g. methanol or DME, instead of hydrocarbon fuels (gasoline and diesel fuels), you need – or can utilize – even more hydrogen. (For various reasons, Chemrec did not succeed commercially but this is a completely different story.) In a situation where the refinery needs to shift the balance from gasoline to diesel fuel, you also need more hydrogen. This is the current situation in Europe. Perhaps this will change if (?) market penetration of diesel cars decreases. However, the most energy-efficient solution would be increasing the share of diesel cars, particularly now when we already know that the NOx problem has been solved. Well, at least this problem will be solved no later than September 1 this year, when the new Euro 6d-TEM regulation is enforced. In a scenario of increased use of diesel fuel, more hydrogen would be needed in the refineries. From an energy efficiency perspective, it makes more sense to use any non-fossil hydrogen in (fossil) refineries and biorefineries rather than opting for direct use of hydrogen in vehicles. If such hydrogen could be produced cost-effectively, there would, for sure, be a big market waiting without any need for change in the fuel supply chain. However, I think there will be some problems with production cost…
Surprise, surprise... If governments and auto manufacturers do whatever they can to reduce the share of diesel cars, this is bound to happen.
@dursun This is also what I have understood. In the US FTP testing, the soak period before cold start is too long for this device to have any effect and in the hot start, the engine is already hot and there is no further potential gain. In "normal" operation, however, we can anticipate some gain. Nevertheless, 8,5% is probably the upper limit and the average improvement will most likely be significantly lower.
Happy end! (?) Today in Europe (at least...), VW is happy to sell more cars than ever. Most of them are gasoline cars, of course. Oil companies are also happy since they can sell more fuel; i.e. gasoline cars use 20-30% more fuel than diesel cars. EPA/CARB are happy since they eventually could frame a manufacturer. Environmental NGOs are happy since they have been fighting diesel cars for decades. By the end of the day, everybody (?) is happy. Those who are proponents of the conspiracy theory could speculate for years to come... Perhaps this scandal also makes them happy.
...and cobalt prices are exploding... at the same time as child labour under terrible conditions in Congo is increasing. Not a good future for EVs. https://www.springerprofessional.de/elektromobilitaet/ressourceneinsatz/dera-warnt-vor-knappheit-bei-batterierohstoffen-wie-kobalt/15907088?fulltextView=true&wt_eCircle_oad=47986&wt_eCircle_nwsl=10974&wt_eCircle_u=19218463960&wt_mc=nl.red.automobil-motoren.1900984193.x https://www.cbsnews.com/news/cobalt-children-mining-democratic-republic-congo-cbs-news-investigation/
Sales of cars with an ICE was 99,3% in 2017 in the EU. It makes sense to invest more...
@LAD & HarveyD Do you really believe what you say yourselves? Easier to build, less expensive... 5X higher performance... flaws and shortcomings... Having seen all the trouble that e.g. Tesla has and how expensive their cars are, I would like to see that you elaborate a little bit on your statements.
Well, they would lose their capital. EV's are not a big business (yet) and if you would have to wait so long for a return on the investment, you would go bankrupt long before. Why would EV's ever become affordable? There are not sufficient rare elements in the earth's crust for that to happen. Likewise, there is not sufficient crude oil to continue with conventional fuels forever. We do not have sufficient biomass for biofuels. Therefore, a long-term sustainable solution will involve improvement of energy efficiency and gradual substitution of fossil (non-renewable) resources with renewable resources (including some supply of electricity but certainly not 100% substitution).
At least better than a Wankel engine, which is not well-suited to the high-efficiency diesel cycle. RR once worked on a diesel version of a 2-stage Wankel engine to get high compression ratio but it never went into production and I presume it was plagued with various technical issues. It should be noted that they refer to "net indicated efficiency" once and "brake thermal efficiency" the second time. Assuming that they would get 45% net indicated efficiency, this roughly equals 40% brake thermal efficiency (depending on what you assume about pumping losses and friction, of course...). This would be lower efficiency than a passenger car diesel engine (~43%) but, on the other hand, this engine is smaller (e.g. ~100 kW for a passenger car engine), which always comes with a penalty in efficiency. Nevertheless, it would be much more efficient than a corresponding gasoline engine of this size. And, as Nick indicated, diesel and/or jet fuel is always available when the military is present.
An eCVT would be worse! The current CVT sucks. Nobody has yet been able to develop a high-efficiency CVT. Personally, I also hate the feeling of a slipping clutch that current CVTs give, i.e. when the engine revs as crazy but not much happen. I recognize that this partly depends on the pairing of engine type (torque and power characteristics) with the transmission and the control strategy in the ECU. However, one simply has to note that the end result counts and I doubt that adding an "e" to the CVT would change that very much.
Yet another manufacturer committed to GPF. Reasonably, this should be cheaper than double injection systems, which some prefer, and give lower PM/PN emissions under "off-cycle" conditions. Logically, GPFs will become a "de-facto" standard for gasoline cars in the future, except for countries like the USA who lag behind when it comes to reducing particulate emissions. Re. diesels: Well, it is obvious that the Euro 6-D standard can be fulfilled with well-developed SCR systems now and that this will give low emissions also in on-board tests.
It is about time... the new regulation comes in force by September 1. It remains to be seen what the impact of the anti-diesel campaigns from Governments and NGOs will be on the long term. The last statistics in Sweden showed a halt in the decrease of diesel share but that could also be due to the end of current incentives and the introduction of a bonus-malus system shortly. If more manufacturers discontinue their supply of diesel cars, it is obvious that the share will go down further. This would effectively kill the most efficient heat engine ever invented (so far, nobody has had a better idea...). Moreover, this would happen when the cars have become as clean as gasoline cars regarding NOx and much cleaner regarding practically all other health effects. That would be the day of joy for all NGOs, who have had this on their agenda for a couple of decades. Perhaps it would have made some sense 25 years ago but not today. However, this is something they will never comprehend no matter how tight emission tight the limits are and no matter how good the margin to those limits will be (as already shown by some manufacturers).
Yeah, Tesla Redux, waste thousands of children in mines in Africa instead so that you... just can go electric! These children will get lots of silly exercise as well. https://www.cbsnews.com/news/cobalt-children-mining-democratic-republic-congo-cbs-news-investigation/
So, here we have a GPF... or OPF... on a small gasoline engine.
@DJ_D No, it has both PFI and GDI (dual fuel injection). Anyhow, also PFI engines have high PM & PN emissions in off-cycle conditions, e.g. at full load or during cold starts at low ambient temperatures. I know, since I have carried out such tests. GPF is the only solution if you want a clean car.
No mention about GPF. Thus, we can anticipate high off-cycle PM & PN emissions.