The Concept IC engine is a reciprocating engine that opens the exhaust valves soon after combustion begins. The inventors claim that the exhaust acts similarly to a recoilless gun so that the piston is still pushed while the exhaust has more energy than a conventional engine, allowing more energy to be extracted by a turbo.

Is this a viable concept?

  • 3
    $\begingroup$ Glancing through the site, it doesn't seem particularly credible at all. Can you elaborate on what you mean by "viable?" $\endgroup$
    – Air
    Mar 4 '15 at 4:43
  • $\begingroup$ I actually really like this question as an educational tool. The process of working through the details of thermodynamic cycles, nozzle and compressor efficiency etc. makes for a pretty interesting exercise. It would actually make a great final exam question in a college thermo class. Short version: no, you're actually stealing power from the piston to run the turbine and that process will never be 100% efficient, so you're losing energy. $\endgroup$
    – Dan
    Mar 4 '15 at 6:23
  • 1
    $\begingroup$ @Dan I'm about certain (for various irrelevant reasons) that it would not be viable, but from a quick skim it seems that the turbine is a power source in its own right and the IC engine is in effect being used as a gas generator. It's conceivable that the turbine can run at higher net temperatures than the IC portion and also will almost certainly use a different thermodynamic cycle so has the potential to make better use of the energy source that it steals from the IC engine. [The word "potential" seems to get more than average use here :-) ]. $\endgroup$ Mar 4 '15 at 6:40
  • $\begingroup$ @Russel: that's an interesting point: while the thing would decrease fuel efficiency, it might increase the peak power output: using up more fuel than the IC could normally accept without choking, but increasing the combustion chamber volume by expanding them into exhaust area; the IC receives same or slightly less power (richer mix, but lower top pressure), but the turbo receives significantly more power, simply because there's much more of the mix burning, even if some of it burns outside the cylinder. $\endgroup$
    – SF.
    Mar 4 '15 at 20:00
  • $\begingroup$ The relevant physics topics are en.wikipedia.org/wiki/Heat_engine, en.wikipedia.org/wiki/Carnot%27s_theorem_%28thermodynamics%29 - one could say he is using the exhaust of one heat engine as the input of another. Together, these can be seen as one heat engine. The second engine uses the still hot exhaust gas of the first, and works based on the temperature difference from that to some cooled reference. Now. it's very important what that cool side temparature is, to determine what could be passible in terms of efficiency. $\endgroup$ Mar 5 '15 at 0:22

Reading through the site I would say no. Using the exhaust gas as input for the turbine will have horrible efficiencies for powering everything he listed. Also, on the "How turbochargers work" page he stated that he uses the compressed air from the turbocharger to directly power a turbine. A turbine and a compressor can be thought of as opposite cycles of the same mechanism...one puts work in and changes pressure, the other changes pressure and gets work out. You would at best be getting the same air and energy as not having a turbo, but since there are mech losses that wouldn't be the case.

To sum, I don't think the heated exhaust would provide enough power for the turbo, water pump, etc as he suggests, and his compressor/turbine combo wouldn't work as he describes (unless I misinterpreted what he stated).


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