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Natural gas is cleaner than E85 and gasoline; at least at the dealer’s office. After a while, its catalyst deteriorates and methane emissions will increase. Most of the HC is methane. Could we live with that? Well, methane is not harmful to human health. We produce it ourselves. However, methane contributes to climate change. The fact that methane contains less carbon per energy equivalent than gasoline is negated by methane emissions that have higher GWP than carbon dioxide. The outcome is about similar to gasoline over the lifetime of the car. However, climate change is not global. It does not happen in the USA, as we have heard your president say.
Well, ethanol is definitely not a “clean-burning” fuel. It has its issues - many issues BTW. Apparently some of you did not bother to read the report I posted as a comment to an earlier article. Shortly, emissions of PAH – note that many of these compounds are carcinogenic – are much, much higher than from gasoline during cold starts at low ambient temperatures. Considering that PAH emissions are the main cause of cancer from vehicle exhaust – much more so than benzene – ethanol proponents should keep this in mind. Solve this problem first, and then push for a large-scale introduction. Fuel and engine must be co-developed. This has not happened (yet) for E85, for blends or for pure ethanol (E100). Fuel switching is not necessary the solution to all our problems. By the end of the day, most alternative fuels can only displace a small part of the fuel pool in the foreseeable future. There are simply not enough natural resources available. Thus, we have to solve the problems of emissions from gasoline and diesel fuels. And we are, in fact, a long way on this route already.
@SJC Diesel engines with DPF are far below the PM limit for real-world (RDE) limits. This is not by a small margin; we are talking about levels at least 90% lower than the current limit. PM (and PN) is mainly a problem for gasoline cars. Recall that the PN limit has been set 10x higher for gasoline cars in the EU but it will now be reduced to the same level as for diesel cars. This is why mass production of GPFs starts this autumn. This is for Europe, of course; not for the USA, where EPA do not bother about small particles. At least some diesel cars meet the RDE limits for NOx by considerable margin. NEDC/WLTP limit is 0.08 g/km and RDE stage 1 limit is 0.168 g/km and stage 2 is 0.12 g/km. One of the “best” diesel cars on the market is the new Mercedes E220. It has NOx emissions, on average in various RDE driving patterns, at ~0.04 g/km. This is about 75% lower than stage 1. Of course it is possible to have low NOx also from a diesel car.
@Trees This article is about a gasoline engine. Why do you bring up E85 in this context? Please stick to the topic if you want to comment on the article. I will do that in my comments below. In my view, this is definitely a high-risk project. If it was low-risk, Renault, or any other car manufacturer for that matter, would do the homework themselves without telling anybody and simply start production as quick as they could, if the project was a success. Ideas like this one has been around for quite some time. It looks like a diesel engine, it walks like a diesel engine and it quacks like a diesel engine, albeit it is still not quite a diesel engine. In any case, they need most of the “internal” engine features and exhaust aftertreatment to reduce emissions. These are, e.g., high lambda, EGR (various kinds, presumably also internal EGR), particle filter, NOx storage catalyst and SCR. As for a diesel engine. The Euro 6d emission limit might seem as a great challenge but recall that you simply need to fulfil this limit if you want to sell new cars. Both conventional gasoline and diesel cars will fulfil this regulation. A more progressive approach would be to aim at something we think could be enforced by Euro 7. After all, it will take such a long time to reach production anyway that you would have to think about further emission reductions by then. One should also recall that there have been several research programs aiming at 55 % efficiency for diesel engines in the past but none of these features (including thermal barrier coatings) has yet reached production status. Reaching efficiencies in the 50-55 % range is not easy. I acknowledge that they try!
Of course this would happen any day. Now, all other manufacturers have to follow. Except in the USA, of course, where nanoparticles is not a problem. Please wake up EPA! BTW admin, this news article should be put in the main section, due to its importance.
Think about this: Diesel passenger vehicles (cars, pickup trucks and SUVs) continued to outnumber hybrid vehicles in all states except California, Massachusetts and the District of Columbia.
@Juan The diesel engine is the most efficient heat engine. In the last 100 years, nobody has invented a more efficient engine. Have you tried? If you did, I would probably not be impressed by your proposal. If we want to preserve resources and minimize climate change, we should, instead, increase our efforts to further develop diesel engines for lower emissions and higher efficiency. Logical! In combination with mild hybridization, both emissions and efficiency can be improved at a reasonable marginal cost.
The big potential for reducing NOx by hybridization is in improving aftertreatment efficiency, which this study has not addressed. The 9% cut in NOx is just engine-out NOx. This explains the big difference compared to the Continental article, as mentioned by “dursun”. For once, you should also try to think like a car manufacturer. If you can meet Euro 6 limits in the new WLTP cycle and, in addition, also in the (coming) real-driving test cycle (RDE) for on-board measurements, what is then the motivation for further reduction of NOx? Our emission standards do not demand more. Customers will not pay more for a car that has even lower emissions. The authors indicate that they can meet those limits even with simplification of the exhaust aftertreatment. This will cut costs. Technical measures not implemented can then be postponed until Euro 7, whenever this standard will come. Finally, the incremental cost for 48 V hybrids is relatively moderate (compared to full hybrids). If this hybridization can cut costs in aftertreatment and other areas, it is a further improvement of the cost-effectiveness. For once, I can also agree with Engineer-Poet. Mild hybrids have greater potential to replace conventional cars on short-term horizon than PHEVs. The incremental cost is prohibitive for the latter category.
@Trees You should read some reports/papers from the study I mentioned before commenting. Of course, the study could only test available production vehicles but there is significant discussion about future development potential of E85. For sure, there has been a lot of research on ethanol fuel in advanced engines during the last years but basically nothing has been implemented on production vehicles. These are just “simple” conversions. Thus, for the moment, E85 and ethanol blends do not provide any real emission benefit compared to gasoline; or diesel if you prefer to use diesel as reference in the comparison. And, as seen in the Swiss study, diesel was much better than GDI. I do not bother to comment in detail on your contribution but let me just mention that there is, in fact, benzene in the exhaust from E85. As said, read the report. You will find data on benzene there. Benzene was lower for E85 at high ambient temperature but there was only a small difference between fuels at low temperature. You should also note that many PAHs are much more carcinogenic than benzene and these were higher for E85. In fact, the mentioned study evaluated the total carcinogenic impact of all the compounds measured. E85 did not score well in this comparison. In contrast, the CNG/biogas car was much better than gasoline.
There must be some seriously ambiguous interpretation of data by Dr. Aung here. Particles in engine exhaust are way smaller than 2.5 micrometer and contribute very little to PM2.5 (total mass up to 2.5 micrometer). Instead, PM2.5, and PM10 for that matter, is dominated by road/tire contact and other sources than exhaust. This has been shown by many researches in the past. For PM2.5, and PM10, it does not help to introduce EVs. On contrary, the EV is heavier than a conventional ICE vehicle and thus, the EVs will create more PM2.5, and PM10. Moreover, the thesis referenced to at the end of the article talks about particle number, not PM2.5. I have not read the thesis but I read the abstract. Nowhere in the abstract PM2.5 is mentioned. I have no problem to comprehend that there are (severe) health effects of “large” particles, such as PM2.5 and PM10, as well as from nanoparticles (perhaps even worse), but one should not blame vehicle exhaust when other sources dominate.
@Arnold You should think twice before publishing such stupid comments on this site, albeit that it is not illegal to do so.
@Trees In Sweden, it was shown already in 2008 that harmful emission components at low ambient temperatures were higher from E85 than from gasoline. See link. This work has also been cited in so many other scientific publications that it is well-known in the scientific community (e.g. search for Westerholm & E85). I attached the link to a home page where the main report can be downloaded for free. There are also several peer-reviewed papers from this work. The excerpt below from the summary is quite clear. Moreover, if we compare to E85 to diesel cars, we also find that these harmful emission compounds are much, much higher for E85. This conclusion is valid at any temperature but, of course, more pronounced at low temperatures. “…increased ethanol content in the ethanol/petrol fuel blends increases emissions of polycyclic aromatic hydrocarbons (PAH) at decreasing (ambient) temperatures, i.e. engine cold start emissions.”
If you look carefully at the graph, you see that only one engine in the graph is environmentally acceptable.
@Trees Ethanol/gasoline blends also generate particles. So does E85, particularly at cold starts at low ambient temperatures. This was shown almost a decade ago. Thus, these engines also need filters, just as GDIs running on gasoline. Besides soot, engines also produce ash from the lube oil. This you get also with gaseous fuels, e.g. CNG and hydrogen (they also need lubrication). Lube oil ash has severe health effects and thus, a filter is needed in this case as well.
YES, what have I been telling you for the last couple of years.
ICCT runs a campaign against diesel. Of course, they try to argue that nanoparticles from GDI is not a big problem. And perhaps it is not – from a legislative point of view. US EPA does not regulate nanoparticles. It is simply not (seen as) a problem in the USA (???). In Europe, however, nanoparticles from GDI will also be regulated and the same limit values will apply as for diesel (previously 10x higher level was allowed for GDI). Moreover, real-drive emission testing will require nanoparticle control under (basically) any type of driving condition. Consequently, car manufacturers now plan to introduce GPFs. Large-scale production starts later this year. There is simply no other way to make a GDI engine clean. Even with perfect combustion, ash particles from oil will be generated. Such particles are trapped in a filter.
Well, all the real driving emissions (RDE) tests I have seen confirm the low NOx mentioned in the article. Generally, ~50% lower than the limit for chassis dynamometer and ~80% lower than the RDE limit to be introduces shortly. Yet, not all technical features commercially available have been used on this engine, implying that further emission reductions would be possible. Most notably would be a NOx storage catalyst (replacing the oxidation catalyst) and direct ammonia injection (e.g. Amminex concept). This just shows that a modern engine can meet very strict NOx emission limits also in real-driving conditions. Of course, these solutions could be "copied" by any other manufacturer.
So, if you buy an EV version of a big SUV, or a big conventional car, then you are environmental friendly (?). Hypocrisy!
No Lad, new diesel car use DPF that give levels at similar - or lower - than ambient air. Soon, we will also have GPF on gasoline cars. Until this happen, however, I can agree it is a problem for the latter category. Conventional gasoline MPI cars have low PN emissions in the test cycle but off-cycle emissions (real driving conditions) can also be high in some cases.
@Juan EV sales has already stagnated in the EU. They are far more expensive than diesel cars. These are the facts.
You need bigger electric machines if you want to cut one cylinder but of course, it is possible. That option might just come with a somewhat bigger price tag; despite reduced number of cylinders (electric systems and batteries are so darn expensive). Eventually, the concept shown here should be very cost-effective, so we might see something similar in production pretty soon. The synergy with NOx reduction is compelling but Euro 6d can, of course, be met with conventional means (you can already buy such cars). A full hybrid with diesel engine would cost more and thus, the total incremental price might be prohibitively high, in spite of lower fuel consumption than the gasoline counterpart.
Lad, you should realize that the PM levels in exhaust from a Duramax are lower than in ambient air in densely populated cities. This cleans the air from harmful emissions in a way that an EV version of the same truck would not do. For sure, NOx emissions still must be further reduced but engineers should have something to work on in the future. Furthermore, an EV version of the same truck would be more expensive and suffer from all other shortcomings of this technology, e.g. low payload in this application. Let’s face the reality: an EV truck would only be good at transporting… batteries. Moreover, if the electricity is produced as in the current US mix, there is little advantage for CO2 and energy use of the EV option.
Well, mahonj, you can use a mild hybrid on a diesel engine as well. It is not forbidden by law. So, that might be the beginning; not the end.
If I read this correctly, they compare the "new" E-class E 350 e with the "old" E 350 CGI. Thus, it would be an apples-to-oranges comparison. The new body is much lighter, has lower air drag and many other modifications that generally reduce fuel consumption. This kind of comparison is not honest. They also calculate on maximum use of grid electricity, which is hardly a likely scenario in ordinary use. PHEVs are generally heavier (batteries) than their gasoline counterparts and usually have higher fuel consumption when operated on fuel. Thus, realistic in-use operation (with much lower use of grid electricity) might yield radically different results that would be less favorably for the PHEV version. Albeit the “biased” conditions, we can see that CO2 is considerably lower for the hybrid. Good! This also increases the resource base for energy supply. Also good! However, when it comes to NOx, the hybrid does not seem to have an advantage on current EU grid mix. Furthermore, one could suspect that the “basis” for comparison (E 350 CGI, i.e. “Predecessor”) is of an older generation which presumably generally has higher NOx than a new engine generation. They do not even mention if the “Predecessor” is Euro 5 or Euro 6. One would assume the latter. The current focus on EVs and PHEVs is contra productive unless we can clean up electricity generation. We clearly have a mismatch here in timing, since the trend of shutdown in nuclear power plants (which in itself is good because we want to avoid any further incidents) will make the EU grid power even “worse” on the short-term horizon. In summary, we should start by cleaning up our electricity generation.
The housing must simply be strong enough to withstand complete rupture of the flywheel. A turbocharger spins at even higher rpm but we accept these risks, and in fact, the turbocharger does not kill people if it breaks. The same, I presume, applies to e-turbos/e-compressors and the built-in electrical machines. I do not see potential risks of the flywheel as a show-stopper. In comparison, batteries and supercapacitors are also associated with potential risks.