Working states of various multi-cylinder engines

zaveri · 2012-07-17T03:46:23+00:00

As the title may suggest, this discussion is about the working of I.C engines, which we are all familiar with. But now what we may talk about in this thread may baffle you (or it may not to some experts). Now talking about the single cylinder engine, we know that the piston does one stroke at a time, and thus a very heavy flywheel is used. as for the 4-cylinder inline engine, each of the four pistons does a different stroke at a time, which means that we get a power stroke at any given point of time, and thus a lighter flywheel is used. similarly for engines having cylinders in multiples of four such as V8 or W12, it is known that pistons in sets of 2 (for V8 ) do a different stroke at a time. But now coming to engines, which have more than one piston but not in multiples of four, the working is kind of confusing. For example take a 3-cylinder inline engine, if one of the piston does a power stroke, then what do the other two pistons do at that time ? got any ideas ?

Working states of various multi-cylinder engines

zaveri

Member

Updated: Oct 26, 2024

Views: 1.6K

As the title may suggest, this discussion is about the working of I.C engines, which we are all familiar with. But now what we may talk about in this thread may baffle you (or it may not to some experts).

Now talking about the single cylinder engine, we know that the piston does one stroke at a time, and thus a very heavy flywheel is used.

as for the 4-cylinder inline engine, each of the four pistons does a different stroke at a time, which means that we get a power stroke at any given point of time, and thus a lighter flywheel is used.

similarly for engines having cylinders in multiples of four such as V8 or W12, it is known that pistons in sets of 2 (for V8 ) do a different stroke at a time.

But now coming to engines, which have more than one piston but not in multiples of four, the working is kind of confusing.

For example take a 3-cylinder inline engine, if one of the piston does a power stroke, then what do the other two pistons do at that time ? got any ideas ?

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PRATIK DOKANIA

Member • Jul 17, 2012

In a 3-cylinder engine, the crank angle is 120 degrees. That means when any one piston is at the TDC, one of the other is approaching the BDC after being pushed by the action of the exhaust gases product (power stroke), 120 degree ahead and the other piston is keaving the BDC after being pushed by the effort of the second piston on the crankshaft and a little effort of the flywheel.

the net effect of all the three cylinders each varying with a 120 crank angle produces the desired motion. However there is one big example of 3-cylinder engine is the requirement of a very light flywheel as compared to 4-stroke or 2-stroke.

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zaveri

Member • Jul 18, 2012

Similarly what happens in a 2-cylinder inline engine ?

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zaveri

Member • Jul 18, 2012

PRATIK DOKANIA
However there is one big example of 3-cylinder engine is the requirement of a very light flywheel as compared to 4-stroke or 2-stroke.
i think you mean to say "advantage" and not "example"

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PRATIK DOKANIA

Member • Jul 18, 2012

My apologies!! It is advantage, not example.

2-cylinder inline engine:

according to the crankshaft angle configuration, these are of three types.

360 crankshaft angle, where both the pistons moth alongside and only one carburetor is required. the size of crankshaft required is more than others and the engine involves huge vibrations

in a 180 crankshaft angle configuration, the pistons are at just opposite locations. it is obvious that the ignition in both cylinders will have to occur at different instances and thus two carburetors are required.

in a 270 crankshaft configuration, the pistons are separated by 1/4 th of a cycle and power characteristics are similar to a V-twin engine.

to compare the above three engines u can refer wikipedia.

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VISHNUGOPAN

Member • Aug 12, 2012

Why is a light flywheel required?

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zaveri

Member • Aug 12, 2012

VISHNUGOPAN
Why is a light flywheel required?

in case of a multicylinder engine, a heavy flywheel would not be required, because power strokes will take place more frequently.

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