Some Questions I Have, please answer if possible.

[v10_viper]

Is it possible to find out the cubic inches by knowing just the stroke, bore, and number of cylinders or does it take more to figure that out, and if there is a formula please tell me.

Has anyone ever produced an engine in a V form that is at an obtuse angle, or have they all been 90º and less?

Also, which is the most powerful engine form? Straight, Flat, V, or Rotary??
I know that straight engines are great for torque but what is the best overall?

[SaabJohan]

Originally posted by v10_viper
Is it possible to find out the cubic inches by knowing just the stroke, bore, and number of cylinders or does it take more to figure that out, and if there is a formula please tell me.

Has anyone ever produced an engine in a V form that is at an obtuse angle, or have they all been 90º and less?

Also, which is the most powerful engine form? Straight, Flat, V, or Rotary??
I know that straight engines are great for torque but what is the best overall?

1. Yes, the displacement volume can be calculated: Pi*bore^2*stroke/4*cylinders
Pi is around 3,1415927

2. V engines can be built with an angle from over 0 up to 180 degrees.

3. Rotary or wankel is a diffrent type of engine using rotating pistons.

No engine form will be more powerful than the other. It's just a different "package".

[ales]

May I also add that the engine in the Renault F1 car is 111 degree V-angle - just to give an example.

Alex

[replicant_008]

2. 180 degrees would be a boxer engine (ie Porsche, Subaru) which is effectively a V engine with the ultimate obtuse angle.

3. There are actually two types of Rotary engines.

Wankel Cycle type engines use an eccentric central rotor and can't really be compared to a piston based engine. Effectively, a rotary could be considered a two-stroke engine with the three zones created by the rotor are a compression/exhaust stroke.

Radial engines are engines where the cylinders are arranged around a central point and radially arranged. Examples include some aero engines.

Each of the layouts has some inherent advantages and disadvantages.

For example, V engines tend to be compact longitudinally which reduces crank length and has advantages in packaging for a given displacement. Hence why this is used a lot in race engines and front wheel drive vehicles. Larger displacement engines also tend to use V arrangements for similar reasons. However, the V also has inherent balancing issues which are complicated by the angle of the V and the different axes of the cylinder banks.

Even different V engines can have different layouts first instance the flat plane crank V8 is effectively 4 sets of V twins mounted together compared to the more common V8 which is effectively two banks of inline 4 layouts.

Inline engines are inherently smoother particularly 6s which fire every 60 degrees of revolution in a 4 stroke. But are fairly long and have a higher deck height compared to other layouts.

Radial engines are great in propeller planes but the deck height makes them difficult to mount in a vehicle.

And flat engines are usually quite wide but can lower the centre of gravity.

[ivymike1031]

a rotary is more like a 4-stroke. There are definite separate intake, compression, expansion, and exhaust portions of the cycle. A two stroke combines intake and exhaust with other parts of the cycle.