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More questions than I can count

  1. Nov 15, 2007 #1
    Apologies to everyone for being so much an asker an so little a responder, though I would like it noted that I do attempt to answer my questions prior to bothering someone with them.

    I do a lot of automotive study but as I get deeper and deeper into the subject, the questions just don't seem to end. So I've decided to just post a bunch of them before they drive me crazy and see what you guys have to say on the subject.

    Can anyone tell me what makes a torque curve on a dyno test so weird? I mean, is there any kinda of relationship I can make to derive a curve if I have enough engine specifications? Im sure inertia has something to do with it since a higher torque is typically generated with increasing engine speed. I saw that this was the integral of the net force applied to the crankshaft, which makes sense since the force is produced in different manners at different degrees of the crankshaft dependent on how much pressure is being generated, I guess through the ideal gas law PV=nRT.

    Of course Im sure to actually graph that I would need to know formulas for:
    How well the cooling system convects heat away from the cylinder
    How much energy is being released at each volume since gas burns for quite some time through the rotation (and subsequently changing the temperature I would imagine, at a rate dependant on how much fuel was put in)
    How much vacuum is created
    How well the fuel atomizes
    How that effects the combustion of it
    And how quickly the gas burns

    I can't really think of anymore questions than that.

    I don't know... Ultimately I just want to know the math behind it all. Even if its pure theory... and we know how well theory and data get along in the automotive world... I think. ='P

    I humbly thank you for all your wonderful help. =')
  2. jcsd
  3. Nov 15, 2007 #2


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    Gold Member

    Read Internal Combustion Engine Fundamentals by John Heywood.

    Chapters 1, 2 and 3 will give you all the basics. The rest of the book will give you all the background info including thermodynamics, chemistry, flow effects, combustion effects, emissions formation, heat transfer, friction, operating characteristics etc.

    If you have specific questions, feel free to post them here.
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