Main Question or Discussion Point
What is the advantage of a big V engine over a V-twin engine? Why not just use extra-large V-twin engines instead of using V-12 engines and such?
Actually no. Engine power is not proportional to RPM but to piston speed:Also, power output is proportional to engine speed, and one huge v-twin engine would not be capable of very high rpms. However it is true that for very large engine applications like cruise ships, very large displacement diesel engines are utilized rather than lots of smaller ones.
I understand you know a great deal about how engines generate power, but piston speed IS related directly to the engine's rotational speed.Actually no. Engine power is not proportional to RPM but to piston speed:
I'm sorry if I did not express myself clearly, but I didn't say piston top surface area as most of the time these are not flat. The area I'm talking about is really the "imaginary" one based on the bore of the cylinder, i.e. A = pi / 4 * D². The displacement (or "imaginary" volume) of that cylinder is this area multiply by the stroke of the piston. It corresponds to the theoretical amount of air displaced by the piston's motion (In practice, it can be lower or greater).That is because the power you can get out of an engine is proportional to the surface area of the cylinder bore (and not to the displacement, as most people think)
Forgive me but is not the displacement of one cylinder the total volume of that bore? and is not volume, the surface area of that bore?? Or did you mean the piston top surface area? Or does surface area of the cylinder bore include the combustion chamber? Would this include the volume of the cylinder head gasket?
Yes, but if you read well my post, you'll notice that piston speed IS ALSO related directly to piston stroke, meaning that it is possible for an engine to have a very low RPM and still deliver great amount of power if it has a very long stroke.I understand you know a great deal about how engines generate power, but piston speed IS related directly to the engine's rotational speed.