engine

hi everone.

just as a general information i want to know whats the difference between 3 cylinder rengine and 4 cylinder engine?

is it like this that the 3 cylinder engine gives high running costs and as a short life?

i am talking of both the petrol and diesel.

Number of cylinders have nothing to do in the life of engine and running cost.

In general more the number of cylinders, the smoother the engine is. But this is just one parameter and there are various engines with different or same cylinders and different characteristics. For instance, chevy spark is 3 cylinder and is pretty smooth. Cannot comment on the Fabia's 3 pots and not yet driven the Estilos 3 pots. I'm sure it cannot be that bad.

In some high end cars, there may be more cylinders but all the cylinders may not be running at all the times. For instance, Honda Accord V6. It can shut down a cylinder when power is not required. It helps in saving fuel.

A little addendum-its the cancellation of opposing forces that makes an engine smoother. Increasing just the number of cylinders will not directly lead to smoothness.

The key is balance and herein comes the concept of even number of cylinders, like 4/6/8/10/12 cylinder engines.

To cite an example the acclaimed Volvo 5 cylinder engines have 1 cylinder more than run of the mill 4 cylinders, but the latter will be more smoother.

Well, IMO for the same CC, a straight 5-cylinder engine will be smoother than straight 4-cylinder simply because now each cylinder will be smaller (lighter piston and/or smaller stroke and/or smaller bore) as compared to the 4-cyl (thus the 5-cyl engine's vibrations are easier to damp out). However both will have vibration due to different effects. 4-cylinder will have no primary vibration but secondary vibration (up-down vibration) and 5-cylinder will have a sort of lateral vibration (engine ends oscillation about the mid-riff in the horizontal plane). 6-cyl (straight-6 NOT V6 - this has the same problem as a 3-cyl engine) or V12 has neither type of vibration so is considered the best. But for economy 4-cyl is the most preferred upto 3.0 Litres. For other numbers the vibrations are damped out or counter-weights/balance rods are used to reduce vibrations.

Edit: My comment about the 5-cyl having lateral vibration was wrong - it will be front-to-back oscillating but in a plane perpendicular to the cylinders' plane. Same for the 4-cylinder - not exactly up-down in a vertical sense but in the cylinders' plane.

S = k.I^2, where S is the amount of stupidity a species possesses, I is the intelligence the species has and k is the universal constant of stupidity.

Well for all practical purposes a four cylinder will have better NVH than a 5 cylinder.

Sorry to bump this thread.

From the above discussion it seems that the new 3 cylinder K series engine in the Estilo and A-star is potentially not as good as the WagonR engine which is 4 cylinder. Could someone clarify?

I keep reminding myself that my car is just a means of commuting

bump. Looking for an answer.

I keep reminding myself that my car is just a means of commuting

It would depend on other aspects too. Cylinders are like lungs & valves like nostrils. The more the better. For normal driving conditions & style (our type of usage), it hardly matters.

Honesty is not a Spare Wheel that you pull out when in trouble. It's a Steering Wheel that keeps you on the right path throughout the life's journey.

Well, not necessarily so because the K-series probably uses better (lighter) materials - so pistons are lighter making it easier to damp out vibrations. However there have been comparisons of A-star (which uses a 3-cyl engine, not sure if its k-series) with M800 in terms of feel when the engine is revved.

S = k.I^2, where S is the amount of stupidity a species possesses, I is the intelligence the species has and k is the universal constant of stupidity.

Looking at the universal trend, the cylinder volume is in the range of 300 - 333 cc. Therefore if the power requirement dictates a 600 cc engine, it is a 2-cylinder configuration (this is a bad generalization, because engine power is not so straightaway mappable to cubic capacity. But for a a general case, it can be mapped so, because if we deviate from this norm, more tricks needs to be employed to get rid of resultant problems, and it also affects longevity - as seen in Accent example).

For a 1L engine, this tells us to use a 3-cylinder configuration and for a 1200 cc it is falling back to 4 cylinders, as the per-cylinder volume goes up to 400 cc.

We see this being followed religiously for engine capacities till 1600 cc. After that the rule breaks down, for probably bill of material shoots up to unreasonable level for a v6 to be employed for 2L engines.

I request an opinion on this. Steer? Binoy? Rohit? Sani?