Intake Design Exploration

[NoDOHC]

I think I need to have a look in the attic, I can't find that book anywhere. From your other threads, it looks like you have done a lot more research than I can remember from old textbooks.

The intake is looking good!

I was thinking that the rotary intake strokes come twice as often as the piston engine intake strokes, meaning that the air had half the time to travel. The intake runner length equation may be off. I will try to get a chance to draw the dynamic model and solve the characteristic equations to see if I can derive the resonance frequency formula properly for a piston engine (it helps to stretch the algebra muscles every so often anyway, as they obviously atrophy). If I can, I will draw the model for the rotary and compare.

[vex]

Originally Posted by NoDOHC

I think I need to have a look in the attic, I can't find that book anywhere. From your other threads, it looks like you have done a lot more research than I can remember from old textbooks.

The intake is looking good!

I was thinking that the rotary intake strokes come twice as often as the piston engine intake strokes, meaning that the air had half the time to travel. The intake runner length equation may be off. I will try to get a chance to draw the dynamic model and solve the characteristic equations to see if I can derive the resonance frequency formula properly for a piston engine (it helps to stretch the algebra muscles every so often anyway, as they obviously atrophy). If I can, I will draw the model for the rotary and compare.

Please do. I have since had that class and now understand what you're talking about. I honestly can't model a dynamic system like this without just retarding it down to a simple mass-spring-damper problem. I do believe the equation I have is correct, though I am of the same concern as you.

The way I looked at it is degrees of rotation compared one to the other. For 720 degrees of rotation of the crank you get 1 intake stroke (Just looking at a single piston), similarly for the rotary you get 1 intake stroke for 720 degrees of rotation (looking only at a single rotor).

I had a simple program at one point that showed the correlation between the intake stroke of the rotary and piston with respect to engine RPM. I'll see if I can dig it up and validate my mental experiment.