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Why not replace 8 cylinders in engine with one cylinder of same displacement?

Question asked by NAVATHE SACHIN in #Coffee Room on Mar 30, 2013
NAVATHE SACHIN
NAVATHE SACHIN · Mar 30, 2013
Member of CrazyEngineers
Why have eight cylinders in an engine?Why not have one big cylinder of the same displacement of the eight cylinders instead? Posted in: #Coffee Room
Jeffrey Arulraj
Jeffrey Arulraj · Mar 30, 2013
Member of CrazyEngineers
The net force required to drive the single piston will be more there by the efficiency of the system will be reduced so go for multi cylinder engines and Never single cylinder engines
zaveri
zaveri · Mar 30, 2013
Member of CrazyEngineers
for a single cylinder engine, you require a heavy and a big flywheel.

now just think of this : how big will the flywheel of the single cylinder engine be, which has the displacement of eight cylinders ?

and in case, this engine is for automotive use, then won't this increase the weight of the vehicle.
NAVATHE SACHIN
NAVATHE SACHIN · Mar 30, 2013
Member of CrazyEngineers
Are there 8 flywheels for 8 cylinders?
zaveri
zaveri · Mar 31, 2013
Member of CrazyEngineers
N.SACHIN
Are there 8 flywheels for 8 cylinders?

Oh no man ! there is only one flywheel for any I.C engine, no matter how many cylinders it has.

what i am trying to say is that the flywheel of a multicylinder engine is far more lighter than that of single cylinder engine.
Gurjap
Gurjap · Apr 2, 2013
Member of CrazyEngineers
Interesting question. Obviously size is not a problem, seeing Fairbanks/Morse and Wartsila manufacture huge diesel engines larger than an average house anyway. Neither is manufacturing, because pretty much anything you want manufactured can be manufactured.

I think the problem might be with control of the combustion chemistry and noise. Would welcome any more inputs on this thread.
Anand Tamariya
Anand Tamariya · Apr 2, 2013
Member of CrazyEngineers
More the number of cylinders, smoother the ride. Also, you can achieve more efficiency by reducing the number of cylinders that fire at lower RPMs and only use full capacity at higher RPMs when you need it.
NAVATHE SACHIN
NAVATHE SACHIN · Apr 5, 2013
Member of CrazyEngineers
There are a couple of reasons why a big 4.0-liter engine has eight half-liter cylinders rather than one big 4-liter cylinder. The main reason is smoothness. A V-8 engine is much smoother because it has eight evenly spaced explosions instead of one big explosion. Another reason is starting torque. When you start a V-8 engine, you are only driving two cylinders (1 liter) through their compression strokes, but with one big cylinder you would have to compress 4 liters instead.
The Observer
The Observer · Apr 7, 2013
Member of CrazyEngineers
do not forget the vibrations it would cause. May feel like a horse ride i suppose. the casing would also get heavy cuz of the energy it is supposed to contain. You need to have balanced masses to counter the effects its gonna cause. a 2 cyl opposed configuration engine may seem better .
riteshbstkr
riteshbstkr · Apr 18, 2013
Member of CrazyEngineers
Hey Sachin
There are so many reasons for why no use of single cylinder rather use of multicylinder
1 there is very high friction for large single cylinder delivering high force
hence problem of lubrication
2 Less compression ratio obtained compared to multicylinder.
3 very less efficiency.
4 one cylinder have very large weight not possible to carry.
Ric Zambales
Ric Zambales · Jan 11, 2017
Member of CrazyEngineers
There would be problems in weight, operation and maintenance of the engine. Imagine in a diesel power plant like where I work every engine has pretty big 16 cylinders and pistons (each has 400mm bore size) and we have 21 units of it. The noise and vibrations are high. imagine those 21 units having much larger single cylinder and piston (each unit will have 6,400mm or 6.4m bore size!) and other parts. it would cause a massive vibration, less efficiency, harder maintenance (due to much more massive parts)

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