Quote:
Originally Posted by jeff88
2 Engines, each 1.8 liters:
- Engine 1: 4 cylinder engine (.45 liters per cylinder) (ex. 79x91.5 borexstroke)
- Engine 2: 8 cylinder engine (.225 liters per cylinder) (ex. 39.5x45.75 borexstroke)
In the end, you still have the same size engine, just the bore and stroke is exactly 1/2 the size of Engine 1 with half the cylinders, but double the size cylinder. I'm thinking this might be more efficient as more cylinders will fire per revolution of the crankshaft.
Any thoughts?
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Engine 1 has 8 times the displacement of engine 2. In order to reduce displacement 50 % you need just to reduce displacement 50 %. Another option is to divide bore with 2^0,5
(79*2^0,5=59)
Fewer cylinders will give you:
- Less surface area for heat loss
- Fewer moving parts means less mechanical friction (pistons, con rods, valves...)
- Smaller engine (one cylinder with 79 mm bore takes much less space than two cylinders with 59mm bore)
On the other hand, fewer cylinders mean:
- More vibration
- Uneven torque output (bigger flywheel)
- Higher piston speed and/or mass (might be a problem at high revs)