I’ve seen quite a few videos talking about different motorcycle engine architectures (?) and their pros/cons and comparissons between them.
The general idea I’ve gathered so far is that moving from 1 to more cylinders, you lose low-end torque but gain top speed, and I assume high-end torque as well.
I haven’t come across any video explaining how the cylinders play their part in this. Why wouldn’t more cylinders equate to more torque across the whole range? Is my main premise wrong?
Note, I’m talking mainly about the “typical” engines, without V or any other weird angles, but feel free to educate me about that as well if you think it’s easily digestable.
In: Engineering
Torque is the twisting force. For a single cylinder engine you have one big cylinder that pushes down *really hard* once every two cycles (assuming 4 stroke) and causes the crankshaft to rotate. For a two cylinder you have two slightly smaller cylinders that push down less hard but you get one each cycle. The smaller cylinders pushing down less hard (because there’s less fuel/air mixture pushing) means that you get a lower peak torque figure.
The trade off is that the single large cylinder has a single large piston, there’s a lot of mass moving up and down and you can’t throw it around too quickly or you’ll start breaking things. Two smaller pistons are each much light and can be revved up higher without over stressing components. Since Power = Torque x RPM (with a scaling factor) the reduction in torque can be made up for by the increase in RPM to get more power in the end
Cylinder count vaguely translates into torque vs power, but it really comes down to torque being closely tied to the size of the individual cylinder and power is going to be determined by the torque and how quickly you can spin the engine with bigger cylinders requiring lower rev limits and small cylinders letting the engine spin stupid fast (See F1 1.6L V6s that run at 15,000 RPM)
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