12 a
          Hi Paul,

          I'm an engineering student who is also working at a start-up aerospace company. I
          would like to learn more about rotary engines. Please point me in the right
    direction.

          Thanks,
          Eric Rinell

          There are two clues to high deficiency of cars and prop driven aircraft,
          They are BSFC and engine power to weight ratio.
          The Wankel can  excel at both. We just set a prop driven aircraft world record on
          time to climb to 10,000 feet which largely depends on engine power to weight ratio.

          The world F1 road racing organization demands turbo compound which raises
          the over all efficiency of the piston engine from 35% to 50%. Turbo compound
    can do even
          better with the Wankel.

          It is time for the world to pull their head out of their smart phones (asses) and
          recognize these facts.

          Paul Lamar



          Turbo-compounding has issues in real-world applications. Back around 2008, my
    customer launched an HD engine with turbo-compound. Customer a major international
    engine supplier with state-of-the-art engineering and development resources. I had a
    few test engines with the turbo compound, but didn't see it in the later MY engines.
    Not sure why it was removed, but I suspect it reduced the efficiency of the after
    treatment (emissions control) system.


    Hakan Uras

    I don't see how it could do that except perhaps lowering the temperature
    of the exhaust gases. Detroit Diesel AKA Mercedes Bence
    sold many  DD15 truck diesel turbo compound.

    NOX reduction is still refused all over the world except in the USA.
    Reducing NOX has a terrible affect on Diesel MPG and Germany refuses
    to do it.  Diesel run wide open throttle full lean high NOX  all the time and the
    power is controlled by how much fuel is injected until you get black smoke.


       I have been in many large cities around the world (35 countries) and I don't see
    anything like the smog we had in LA back in the 60's.

    I have never found any data that NOX, in typical atmospheric concentrations,  affects
    the health of people. If you have some please upload it.

    Paul Lamar


DDC/MB phased out turbocompounding in 2015 or so. If you look on DDC's website, there is no more mention of it.

Turbocompounding causes issues with emissions control because all catalysts need heat to function. Below a certain temp threshold, catalysts don't do anything. Once they get to temp, they are virtually 100% efficient. Adding a 2nd turbine downstream of the turbo reduces exhaust temp, so it will reduce the efficacy of the emissions control system. Turbocompound does work to improve fuel economy. That's been proven repeatedly. You are correct that it would be especially effective on a Wankel since the exhaust temps are higher then on a piston engine, so the enthalphy of the exhaust is higher (e.g. there's more energy to drive the turbo-compound).

Europe, Germany included, has regulated NOx for years. If you buy a new diesel vehicle in Germany, it will be equipped with a NOx aftertreatment system.

Hakan Uras




Perhaps VW passes the German  NOX test the same way they did it in California :-)

https://www.dw.com/en/angela-merkel-aims-to-ward-off-diesel-car-ban-in-germany/a-45978487


"  Angela Merkel aims to ward off diesel car ban in Germany

Angela Merkel has pledged to introduce legislation to stop "disproportionate" bans on diesel cars. The chancellor was speaking ahead of the state election in Hesse, where her CDU is desperate for a good showing.German Chancellor Angela Merkel has warned it would be "disproportionate" to ban diesel cars in cities where limits on nitrogen emissions are only being marginally exceeded.


Speaking to reporters in Berlin on Sunday evening, Merkel pledged to introduce legislation that would allow car owners to continue driving older diesel vehicles.

Many drivers have been left outraged as a number of major German cities — including Frankfurt, Berlin and Stuttgart — have threatened to limit or ban older diesel engines from their roads <https://www.dw.com/en/court-orders-partial-ban-for-diesel-cars-in-berlin/a-45813568>."

Merkel said diesel car owners should not bear the costs <https://www.dw.com/en/opinion-diesel-drivers-are-voters-too/a-45727046> of having their older diesel engines retrofitted with catalytic converters, which would reduce the amount of nitrogen emissions cars produce.

Diesel car emissions have raised nitrogen levels above the permitted level of 50 milligrams per cubic meter in several cities across Germany.

However, Merkel's proposed legislation would enshrine in law that diesel car bans are disproportionate in cities where there are only marginal excess nitrogen levels. In Frankfurt, for example, the nitrogen level stands at 57 micrograms <https://www.dw.com/en/frankfurt-must-ban-old-diesel-cars-court-rules/a-45373435> thanks largely to a series of environmental measures, such as the introduction of cleaner buses.

End quote.


Maybe pig piss is the answer :-)

Paul Lamar


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