More questions than I can count

[mahoutekiyo]

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? I am 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 I am 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. =')

 

[brewnog]

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.

 

[ravenprp]

First of all, there's no need to apologize for asking questions. Asking questions is how we learn and deepen our understanding of a subject. It's great that you are actively seeking answers and trying to understand the concepts behind them.

The torque curve on a dyno test can be affected by a variety of factors, such as engine design, fuel type, and environmental conditions. In terms of a relationship to derive a curve, you can use engine specifications such as engine displacement, compression ratio, and valve timing to predict the general shape of the curve. However, it's important to keep in mind that the actual curve may vary due to other factors.

In terms of the integral of net force applied to the crankshaft, you're correct that it is related to the torque curve. The ideal gas law can also play a role in the combustion process, but it's not the only factor. Other things like fuel atomization, combustion efficiency, and cooling system effectiveness can also impact the torque curve.

As for the formulas you mentioned, they can definitely play a role in understanding the torque curve, but they are not the only factors to consider. It's important to remember that engine design and tuning also have a significant impact on the torque curve.

In terms of the math behind it all, there are certainly formulas and theories that can help explain the torque curve, but it's also important to gather real-world data and test different scenarios to fully understand the complexities of engine performance.

Overall, keep asking questions and seeking answers, but also remember to approach the subject with a combination of theory and practical application. Good luck with your automotive studies!