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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.
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.
This article is mainly about gasoline cars and GPF. The second paragraph (about diesel) should not have been included in this article.
Euro 6d-TEMP engines are subject to RDE testing (on-board emission testing). Defeat devices will be detected and those who cheat will be punished. From September 1, 2018 all cars have to fulfil this regulation. In essence, this is as "safe" it can be regarding your desire for low emissions. If you do not want to wait for Euro 7, or Euro 8 and so on... But then we are discussing ~2025 timeframe and further.
So, we can expect more child labour in cobalt mining...
Lad One of the most polluted places in Europe is "Neckartor" in Stuttgart. The average concentration of NO2 there was 73 ug/m3 in 2017, i.e. well above the EU limit of 40 mg/m3. The limit in the USA (at 53 ppb) corresponds to ~108 ug/m3. This strange situation was pointed out already in the recent Bosch paper; for those who bothered to read it. The mentioned US limit for NO2 has been set well below the level when any harm to humans is considered to happen. EU seems to be more cautious and perhaps we even focus at the "wrong" emission component. NO and NO2 are "natural" substances in our body and most likely, there is a threshold level, which is not the case for other emission components, e.g. PM and PN. All-in-all, we could conclude that the level at one of the most polluted "hot spots" in the EU is well below the limits in the USA. In fact, Stuttgart would presumably be considered a very clean city, if it was located in the USA. Fortunate for you, Americans, is that you tolerate much higher NO2 levels than we do in the EU. Lad, what children should we care for? What about the children in Congo who produce cobalt for BEV batteries?
Well, dear EU Commission, start to promote gasoline engines for HD vehicles and you will get +15% and +30% CO2 instead. This is what is happening right now with light-duty vehicles.
I would like to add a reservation regarding very low on-board NOx levels. In general, on-board instruments are not as “good” as laboratory instruments. On-board instruments must be much smaller than laboratory instruments and the (instrument) manufacturers have to cut some corners somewhere. As an example, Horiba’s laboratory NOx instruments have a 10-fold lower range and, presumably, corresponding detection limit than their on-board instrument. If you are at, or close to, the detection limit, only a small error in instrument calibration against the calibration gases (as you have to do prior to any measurement) will give a small offset; low or high. This means that the average level over the test cycle might be a little higher; or lower. I would assume that at ~20 mg/km you are close to the detection level for current on-board instruments. In an extreme case, and taking all other variation into account, you could one day get 30 mg/km and the second day you could get 10 mg/km, since you might have up to +/- 10 mg/km in scatter. Therefore, I am cautious when people start to talk about single-digit NOx levels from on-board measurements. For sure, it will be possible to improve on-board instruments further in the future but perhaps we should only say that a level below ~50% of the Euro 6d “final” RDE limits of 120 mg/km (diesel) and 90 mg/km (gasoline), let’s say <50 mg/km, is just “very low” and not try to distinguish between different cars below this level. Moreover, if we cannot measure the levels, we should be happy and conclude that the cars are clean.
All-in-all, improvement of SCR catalysts (lower “light-off” temperature) over the last years has led to that urea hydrolysis is now a limiting factor; not the SCR catalyst itself. You have to make ammonia from urea and this cannot be done under a certain temperature threshold. Off-line treatment of urea via a heated catalyst could be one way of further improvement, or else, storage of ammonia in a different way than urea (e.g. Amminex). In a recent article in ETI, Loughborough University claims they can come down to 60 deg. C but perhaps this number should refer to a decrease in light-off temperature rather than absolute number. A break-through of one of these concepts might drastically reduce NOx emissions further. Besides the improvement above, there is also additional potential in both internal and external EGR that has not yet been exploited. Thus, engine-out NOx can be reduced, most likely without any fuel penalty. An additional advantage is lower urea consumption. For increasing exhaust temperature, the most obvious improvement is downsizing. Instead of a 4-cylinder 1.6-liter engine, a 3-cylinder 1.2-liter engine could do the job. A mild hybrid system plus additional e-compressor can increase power and facilitate good drivability. 150+ hp is not impossible from such a small engine or ~120 hp with a single turbo from a lower rated engine. Extended engine stop periods (over conventional start-stop) will avoid cooling of the catalysts due to low exhaust temperature at low engine loads. If nothing of the above helps, an electrically heated catalyst can increase exhaust temperature and shorten warm-up. Also, an additional underfloor SCR catalyst with second urea/ammonia injection after the SCR/DPF could further reduce NOx under some operating conditions. The emission problem of diesel cars has never been a technical issue. Of course, SCR technology was new in this application and need some time to mature but mostly, the car manufacturers have not done their homework properly and they have also exploited loop-holes in the current regulation. State-of-the-art technology today goes beyond potential Euro 7 limit (assuming ~35 mg/km in WLTP and ~50 mg/km on-road). A level of <20 mg/km is certainly possible in a couple of years for all cars since some cars today already reach this level. This would be a substantial improvement over the on-road limit of 168 mg/km that comes into force in September 2018.
There is really no new hardware presented by Bosch, as many on this site seem to believe. Bosch has just optimized a concept that has been used for a couple of years. VW introduced this technology in 2014 (presented in a paper in the MTZ journal) for the heavier vehicles (smaller cars use only LNT, i.e. no SCR). Note that this was a later engine generation the one that got caught in the USA and also later than the Euro 5 engines that were in the grey zone and needed recall. In a most generous assessment, one could say that Bosch concept represents the second generation of this concept and that they have developed this to perfection by improvements in detail and better software control under all operating conditions. A few hardware features: • Multi-way EGR (both high-pressure and low-pressure EGR). In the VW case also VVT that give some internal EGR (presumably, the engine used by Bosch does not have this). • Clouse-coupled aftertreatment. This gives a 30 deg. C increase in exhaust temperature compared to underfloor SCR, according to a paper by Mercedes. • SCR on DPF (instead of a separate underfloor SCR catalyst) • LNT catalyst before DPF) Apparently, Mercedes does not use an LNT. Perhaps they do not need it. Moreover, they claim in an MTZ paper that they need no catalyst heating strategy at cold-start, i.e. no fuel penalty. Besides Mercedes, and VW group to some extent, the best on-board emission results come from BMW. In contrast to Mercedes, BMW use LNT plus separate underfloor SCR. The disadvantage is lower SCR temperature but perhaps they use the LNT to avoid this problem. I presume it requires much software calibration to perfect the system. Surprisingly, BMW does not use long-route EGR on their newest engines. Perhaps they do not need it. Instead, they use twin-turbochargers also on the lower rated engines. This improves transient behaviour and also reduces NOx spikes and, in combination with LNT, LR-EGR is not needed.
It slipped my mind that the VW engines introduced in Europe (later generation than the ones they used in the USA when caught cheating) in fall 2013 basically used a similar concept as this one (PSA, Ford, Opel, etc.) but also the Bosch article. However, VW also had an option with NSC catalyst for smaller cars. The one in discussion here is usually referred to as "SCR" but it also comprises an NSC catalyst, which I had forgotten. Detailed information about that VW engine can be found in a paper in the MTZ journal of June 2013. In the previous generation of the PSA-Ford 1,5/1,6-liter engines, no NSC catalyst was used, at least as I am aware of. They also refer to higher urea consumption than the previous generation, which indicates that they control the engine/aftertreatment in a better way than before. This must be in response to the RDE regulation, since the old engine was not that clean in on-road measurements.
You in the US must now (again) blame the diesel cars and VW. Er... I just realized that VW does not sell diesel cars anymore in the USA.
I found this picture of the Peugeot 308 engine that should be very similar. They use an NSC catalyst and SCR on DPF. Nothing new, really, except that the combination is not (yet) so common.
@Lad This is a guy who has no money, no technology, no customers and no hope (?). Anyhow, we could always hope that he succeeds.
The Bosch paper is available for free downloading, so we do have a detailed description about the technology. As I said in a previous thread, there is no new hardware. Everything they used i already in production. The VW paper has been presented at the Vienna conference, so those who attended will have the paper in the conference proceedings. The rest of us will have to wait until it is available via the organizers (very expensive) or hope that VW will publish it.
I found the complete paper from Bosch. Usually, the conference organizer asks a fortune for the whole package of conference proceedings.
@LAD Building clean(er) ICE cars that cost much less and use less rare elements than EVs is a really good idea.
This must be the new PSA (Peugeot, Citroën & DS) 1.5-liter engine, since Opel is now part of the PSA group. This engine has previously been certified according to Euro 6d-TEMP in several PSA vehicles. Presumably, this would indicate very low (NOx) emissions.
@Engineer-Poet, For once, I could not agree more with you. Gradual improvement and a stepwise introduction of hybrid technology in large-scale production, starting with mild hybrids. Evolution rather than revolution.