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Automotive Can hot air replicate the sound effects of exhaust gases?

  1. Dec 12, 2016 #1
    Hey guys, is it possible to replicate the sounds produced by exhaust gases in a car by using only hot air? Thanks in advance for your responses.
  2. jcsd
  3. Dec 12, 2016 #2


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    Is this about just getting 'sound effects' or is it about some scientific test or experiment ?

    Tell us more in any case .
  4. Dec 12, 2016 #3
    Suppose we replace the exhaust gases by air. The composition is different, but both of them still contain mostly nitrogen. How does the speed of sound, the density and the acoustic impedance change if part of the oxygen is replaced by CO2 and H2O ? There will be differences in the acoustics, but it is probably not large.
  5. Dec 13, 2016 #4
    Thanks for the responses, basically I wanted to know if it would be possible to harness the heat generated by electric motors & batteries and channel to produce sound so that electric cars would sound just like conventional IC engine cars.
  6. Dec 13, 2016 #5


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    You could generates the sounds in the passenger compartment electronically just using loudspeaker systems .

    Nice idea in principle though . Anyone with a modern boring box on wheels could choose to program in their choice of car sounds .

    Imagine a Mondeo that sounded like a race tuned 6 1/2 litre Blower Bentley .
  7. Dec 13, 2016 #6


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    I'm guessing that Khumo is less interested in esoteric aesthetic sounds than in road safety.
    Porsche and VW cars have had air cooling for IC engines in the past, but I don't know if that produced much sound.
    If these electric cars need some forced air cooling, maybe it could be made deliberately noisy without wasting to much power.
    I think the original question is a bit off track, as the sound of IC engine exhaust has more to do with the pulsed gas flow forced by the IC process, than to do with the fact that the gases are hot or anything to do with their chemistry. Electric motors'cooling air would more likely come in a continuous stream with only turbulence noise. But if it were driven by a rotary blower, perhaps a small cyclical bleed - like old WW2 mechanical sirens - could produce a pulsed air flow to a resonant tube and matching horn?
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