Posted on 10/09/2004 1:09:21 PM PDT by doug from upland
not sure, Mercedes is the leader in this. I think its just a container that injects urea into the exhaust stream as a reactant. it may be just an empty container when exhausted.
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Urea Based Cataytic Converter for Diesel Engines Topic: Research & Technology
In the near future the usual summer ozone peaks exceeding the allowed threshold may be a thing of the past: the Paul Scherrer Institute (PSI) in Switzerland has developed a new type of catalytic conversion system, which filters nearly all nitrogen oxides out of diesel exhaust gases using a refined control technology. This eliminates the main cause of summer ozone build-up. The process requires a non-toxic urea solution, which future diesel engine commercial vehicles can take with them in a separate refillable tank.
Diesel engines are looked upon as relatively economic and environment-friendly, because they have a better fuel efficiency than gasoline engines. But burning diesel also has a grave disadvantage: it produces nitrogen oxides, which enhance the build-up of hazardous ozone during periods of high solar radiation. “In the end, diesel engines today are the main cause for high ozone values during summer”, says Oliver Kroecher, Exhaust Gas Aftertreatment Group Manager at PSI. Already by 2005, exhaust gas standards for diesel engines are to be tightened massively throughout Europe. And further steps reducing the threshold are planned.
To comply with the new threshold values engine manufacturers are now focussing on the so-called SCR (Selective Catalytic Reduction) technology. Here nitrogen oxides are transformed into nitrogen and water vapour using a catalytic converter and by adding a harmless urea solution. This compelling principle could establish itself in the foreseeable future in all commercial diesel-powered commercial vehicles. In future drivers should get used to refilling an additional urea tank.
Zero emission for combustion engines is long term objective
PSI scientists have now developed a practicable SCR catalytic converter that disposes over 90% of the nitrogen oxides in exhaust gases. Kroecher describes the PSI advantages over other SCR prototypes: “Our converter has minimal dimensions and can prevent the escape of ammonia generated during the reaction, thanks to an ingenious regulating system.” To optimise the nitrogen oxide dismantling, the amount of urea added adapts continuously to different drive phases. “Our regulator system all but anticipates the engine activity and can therefore react fast enough to changes”, says Kroecher.
With the nitrogen oxide output going down the problem with harmful soot particles from diesel engines will also be defused. While diesel engines could be tuned to a low soot production, this will however increase the nitrogen oxides. The new SCR catalytic converter strongly reduces this drawback. PSI researchers want to achieve even more. Kroecher: “In the long run, we’re working on zero-emission concepts, in order to develop combustion types creating no other pollutants than carbon dioxide.”
The work on the SCR catalytic converter was carried out together with industry partners and with the support of the Swiss Federal Office of Energy. The Measurement and Control Laboratory at the Swiss Federal Institute of Technology (ETH) in Zurich developed the advanced catalytic converter process strategy. Commercial products based on the PSI know-how will be introduced to the market in the near future.
Visit: http://www.psi.ch/.
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that's it.
The capacitor would be charged by dynamic breaking as the vehicle was slowed down, and could be further charged as the vehicle either maintained a slower speed or was sitting motionless. I don't know the details, but my guess would be that the capacitor would have an "optimum" charge level for any given speed of motion and would be charged any time it was below optimum and spare horsepower was available from the engine.
Well, yes, but they will make it up in volume!
Toyota said 100,000 additional hybrids for 2005...
Throw your snow chains in the box, just in case. The afternoons are looking more and more like winter.
BTTT!!!!!!
Timing is everything. A "flash boiler" can have a small amount of steam available within 30 seconds of flame ignition, and with careful engineering of the system for heat reclamation, and keeping the water hot (just a few degrees below boiling) by use of high-grade insulation, adequate road power should be available within 3-5 minutes, not a bad trade-off considering that internal combustion engines also have a warm-up period before they are at optimal performance. By starting the steam cycle by a remote starting device (similar to remote starting devices used in snow country to start vehicles parked in driveways), the vehicle should be ready to go when you slip behind the wheel.
Abner Doble built such a power plant back in the late 1920's, and put it into cars that could be driven on a transcontinental journey (Howard Hughes had one). But these were practicaly custom-built vehicles, and only a few examples exist today, most non-operating. The design was not that complex, apparently, but the materials technology of the time was dreadful, and attempts to reverse-engineer from existing examples are hung up on the difficulties in casting a clean reproduction of the Doble cylinder block configuration. And besides, old Abner was constantly tinkering with the design, and no two were ever quite the same.
The last Stanley Steamers (about 1924) had a similar flash boiler feature.
Each cylinder had a spark plug wired to a distributor that fired each cylinder at 120 degree intervals.
An engravure affixed at the bottom right-hand corner of the case showed a man dressed quite nicely and bent over apparently breathing from the big end of a constructed funnel attached to the large exhaust pipe from the center cylinder.
I would have sworn it was called a Franklin design but no on-line search discloses such a design or history that I can find.
But it remains intriguing.
Really? I get over 50mpg from my hybrid, mostly highway driving.
Next myth, please.
That's just dumb.
How can you compare the Echo to the Prius?
Where's all the room? The navigation system? The 9 speaker stereo? The auto climate control? The bluetooth handsfree system? The homelink system? And so on.
The Prius is slotted alongside the Camry. You can drive your lil econobox, but that's not for me.
I don't have a little car. I've got three SUVs.
A significant improvement in internal-combustion-engine efficiency can be had by "compounding": taking the exhaust from one cylinder and using it to drive a larger cylinder whose piston is 180 degrees out of phase. Because a "compounding" cylinder can be used on every revolution unlike a four-stroke power cylinder which is used every other revolution, two power cylinders can feed one compounding cylinder. Perhaps that's what the engine you saw did.
Another Freeper just freepmailed me a proposal which would apply the same concept on an inline-four when the power demands were not great while maintaining the ability to operate as a conventional inline-four when maximum power was needed. Seems like an excellent concept to me, since the efficiency improvements available through compounding are quite significant and most automotive engines spend most of their operating time far below their peak power levels.
Interesting.
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