KnifeEdge_2K1
09-03-2004, 10:04 AM
while we're on the subject of engines maybe we should discuss the harmonics of each type of engine like why 3 cylinder engines need a balancer shaft while a 4 cylinder needs twin ballencers while 6 cylinders dont need em at all
i understand it but cant explain it
basically the 3 cylinder will jump up and down because of how the crankshaft and pistons are aranged while a 6 cylinder doesnt because its just two 3 cylinders glued end to end cancelling out each others up down movement
as for twin ballencer shafts in the 4 cylinder engine its gonna take a while
as you may imagine a 4 cylinder inline engine will be comepletly ballenced for the first order force
imagine this
1234
- -
--
this is basically the layout of all inline 4 cylinders
the group 1,2 ballence each other while the group 3,4 ballence each other
the problem is however when piston 1 is at the very top of its movement of the crank shaft piston 2 would be at the bottom but moving slower due to the geometry of the engine
the slower velocity will cause the displacement ratio (sorry i cant put it in better terms) to change causing vibration
this same thing also happens to 3 cylinders (i think) but since most 3 cylinders are low in displacement this effect is minor while in 4 cylinders its more pronounced since they usually have larger displacement, its generally agreed that all 4 cylinders with 2 litres of displacement or more need twin ballencer shafts to operate smoothly and efficiently
ive drawn up a picture to explain this but its kinda hard to understand
i understand it but cant explain it
basically the 3 cylinder will jump up and down because of how the crankshaft and pistons are aranged while a 6 cylinder doesnt because its just two 3 cylinders glued end to end cancelling out each others up down movement
as for twin ballencer shafts in the 4 cylinder engine its gonna take a while
as you may imagine a 4 cylinder inline engine will be comepletly ballenced for the first order force
imagine this
1234
- -
--
this is basically the layout of all inline 4 cylinders
the group 1,2 ballence each other while the group 3,4 ballence each other
the problem is however when piston 1 is at the very top of its movement of the crank shaft piston 2 would be at the bottom but moving slower due to the geometry of the engine
the slower velocity will cause the displacement ratio (sorry i cant put it in better terms) to change causing vibration
this same thing also happens to 3 cylinders (i think) but since most 3 cylinders are low in displacement this effect is minor while in 4 cylinders its more pronounced since they usually have larger displacement, its generally agreed that all 4 cylinders with 2 litres of displacement or more need twin ballencer shafts to operate smoothly and efficiently
ive drawn up a picture to explain this but its kinda hard to understand