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-   -   Car with four cylinder engine or three cylinder engine? (https://www.team-bhp.com/forum/technical-stuff/65785-car-four-cylinder-engine-three-cylinder-engine-2.html)

Since a five is the smellest engine where the power strokes overlap. As for crankshaft disbalance etc. this is not too tough a technological problem to solve.

Add the Accent CRDi to that list.

Jaggu, how much would 10k matter in a car of 4 Lakhs ? That is not savings, the real savings is in the kmpl.

By having a three cylinder engine, the major savings are from following items:
a. cylinder
b. piston
c. piston rings
d. valves
e. spark plug
f. HT wires
g. Fuel injector

Also usage of space in engine compartment is also a valuable commodity.

There is some savings, but it is hardly anything , especially in a production environment, compared to the busness benefit - offering a more fuel efficiency product -which may be a unique selling point (USP) for the sales.

10k over 10,000 engines = 100,000,000/- doesnt it make sense?

Now Nissan Micra also joins the league.

@Sunil - Good article & nice to have you bumped up this thread. Anyday, I prefer one cylinder to 4 valve combination on 2/4/8 cylinders; sounds to me like a good balance; like you said there's no gap in the 4 cylinder configuration & there's always power stroke on any one of the cylinder at any point in time & I believe that makes the balance.

Well,

There are many aspects which are considered, before an engine
(which is a heart) for any automotive is considered.

1) The market segment
2) Application expected (City travel car, SUV, MUV etc)
3) Competitors


Example

A hatch back has some constraints like cost, space(overall dimensions), and finally amount of HP that defines the car as powered to perfection.


Where as

A premium luxury car would be to fill the car with a heart (Engine) to its brim which would fill the pleasure of driving irrespective of many constraints which may apply in other cases.



Now looking at the above scenarios company tend to come up with solutions

may be three cylinder which certainly would save material cost, space but at advent of imbalance (Companies try to remove the imbalance to a extend) due to three cylinders which would ultimately show up in the NVH.

As people have stated about some three cylinder engines feel of some roughness and the some harshness.


To sum up these things.

Three cylinder 800cc

Competitively priced however does have a roughness and harshness

Four cyclinder 800cc

Bit highly priced however has very good NVH (due to good balanced engine)

That's no comparo! A 4-cylinder would any day be better than 3-cylinder. No matter what the manufacturer tells about advancement and blah,blah,blah.... ( which is basically a bullcrap ), they do it JUST to cut costs and boost that all important "mileage kya hai?" If this not so then we wouldn't have supercars with V6, V8, V12 and W24 cylinders. We would have then had single cylinder Ferraris and Lambos.:)

Another thought stuck me after reading this thread (thought nothing about the technical merits of one compared to other)

The most common engines are 1.2l and 1.6l engines. Now each cylinder in a 1.2l - 3 cylinder engine and a 1.6l - 4 cylinder engine is 400cc.

So the cylinder design for the two engines can be common. This may lead to less part types and hence less inventory, NRE, etc. .... and better cost savings for the manufacturer.

The Zen was always a 4 cylinder one! ALWAYS sir.


There is a lot more that goes into a vehicle design and manufacture than what meets our eye.

Some points I can think of are:

1. Marketability
2. Cost of Manufacture
3. Use of a common platform from the existing library [Almost all manufacturers do this]
4. The Target segment
5. Use of a engine available with a partner company [Suzuki - GM - Fiat - TATA Tieups etc]

Also, in a three cylinder engine, there is a Power Stroke every 120 degrees and in a 4 cylinder, there is a Power Stroke every 90 degrees.

Hence it appears that a 4 cylinder is always smoother than a 3 pod engine.

Changes in technology bring about a lot of good things.

About the potential loss of engine power when using AC - One would not feel it if the engine is BIG enough. It does not matter whether it is 3 or 4 or 12.

A little OT:

Are you guys aware that a small company in coimbatore has designed and developed a 7 cylinder 70cc rotary engine bike :Shockked:

That would be true if the cylinders were individual pieces joined together to make a 3 or 4 cylinder engine as required. And that is never the case. There's far more to an engine than the cylinder itself - and that's where the challenge lies. Not just the bore & stroke dimensions and the number of cylinders in the block.

I agree with you that having common cylinder design is beneficial. Let's say I have a 4-cylinder 1.6 L engine. If I want to create a smaller engine, the cheapest way is to cut off a cylinder with a minor redesign of other components. To create a new 1.2 L 4-cylinder engine, new combustion models, etc for the cylinders would be required and hence development costs would be very high. But my keeping the same cylinder design, cutting off a cylinder would give a quick fix.

Remember Maruti went the other was with the 1.16 litre engine of the Alto VX/Wagon R/ Estilo. They added a cylinder to the M800 3-pot.

Wikipedia says that Maruti developed that engine, I always thought that Suzuki already had that engine abroad. Can someone verify this?

Either which way, it corroborates my logic of not having to design new combustion chambers.

Yes, it appears from web excerpts that Maruti has indegeniously discovered the 4 cycle engine in India. According to Wikipedia, A-star is the newest version of Alto but I dont understand the technical connection shared between them.