Intake Design Exploration

[NoDOHC]

The nice weather will soon be over. This sounds like a winter project with a notepad and a calculator. I think I loaned engine dynamic analysis book to a friend, as I can't find it anywhere. If I can find it, I will try to derive the equations for a rotary engine (from the piston engine equation derivation explanations in the book). It has been too long since I studied any of this for me to trust my memory.

I know that the rotary engine has a 298 degree intake port duration each revolution, making the airflow into the two rotors overlap (one is still filling when the other starts). This is also why the engine is so smooth, as the power strokes of the two rotors overlap. The actual maximum to minimum volume cycle of the engine occurs in 270 degrees of eccentric shaft rotation.

Do you have an engine apart so that you can get a feel for what it does as it turns?

I can try to get pictures, but a photographer I am not (as I think is evidenced by many of my pictures on this site).

For what it's worth I think this development is very helpful to the community and I appreciate your enthusiasm and effort on the project so far.

Thanks!

[vex]

Originally Posted by NoDOHC

The nice weather will soon be over. This sounds like a winter project with a notepad and a calculator. I think I loaned engine dynamic analysis book to a friend, as I can't find it anywhere. If I can find it, I will try to derive the equations for a rotary engine (from the piston engine equation derivation explanations in the book). It has been too long since I studied any of this for me to trust my memory.

Yeah, sounds good... though with the colder weather comes more homework assignments for school for me.

I know that the rotary engine has a 298 degree intake port duration each revolution, making the airflow into the two rotors overlap (one is still filling when the other starts). This is also why the engine is so smooth, as the power strokes of the two rotors overlap. The actual maximum to minimum volume cycle of the engine occurs in 270 degrees of eccentric shaft rotation.

That I understand, but for sizing the actual intake runner length you need only concern ourselves with one intake volume as the pulse from the closing of the intake port results in the wave propagation to achieve higher VE of the engine (in other words we don't really need to worry about the intake overlap charge). The wave travels the length of the runner at a specific RPM and results in a compression wave of air being sucked into the next rotation of the rotor.

Do you have an engine apart so that you can get a feel for what it does as it turns?

No... but I do have a nice program to validate different cycles of various engines to ensure synonymous application of the formulas considered.

I can try to get pictures, but a photographer I am not (as I think is evidenced by many of my pictures on this site).

There's really no need unless you really desire to.

For what it's worth I think this development is very helpful to the community and I appreciate your enthusiasm and effort on the project so far.

Thanks!

As always I appreciate your input and help with my engineering cog turning exercises. Hopefully the final iteration of the formula will facilitate the proper lengths and diameters of the intake runners.

In the meantime however I need to do my boundary layer theory report.