while this is interesting and all, History seems to side with Milehigh on this one.
It was discovered in the days of early locomotive trains,
when 4-cylinder Sterling engines were being used to ship goods across the country
the resonant frequency of the combustion chamber
(think of it as the tube of a pipe organ)
results in an uncontrollable vibration that shook the entire train to pieces.
every since then, engines were designed NOT to do this.
from the intake, to the stroke distance, the explosion time, to the exhaust.
This timing is intentionally designed to NOT be resonant with the combustion chamber.
Otherwise, the standing wave would make the engines RPM unpredictable,
and cause unwanted vibrations at the resonant frequency, throughout the entire vehicle.
This is just one form of resonance that can occur (the primary one) within an ICE.
there are also, resonances that can occur within the drive-belt system.
diameters of pulleys, spinning masses, tension, and a tiny wobble in one of the pulleys,
at just the right rpm, you can shake the engine on its' mounts!
there are also resonances that can occur within the exhaust system,
as it pertains to RPM, back-pressure, lengths and diameters of the pipes, etc.
one of the functions of the muffler/cat is to restrict flow to prevent resonance.
full resonance resulted in a violent 'sputtering' of the exhaust
while half-wave created a vacuum in the exhaust manifold that decreased the overall power of the engine.
or even back-firing
cars that remove these components can sometimes experience this.
Now, half the bore of your engine, squared, times pi,
which is coincidentally, the displacement, as well as the volume of the resonant standing wave...
is a frequency in the Ghz range.
so the resonance you are incurring is the 6th lower harmonic.
or rather, the 6th higher harmonic of the engines RPM can be resonant with the combustion cylinder.
[this is unwanted]
I said that both ways, so everyone gets it.
I like to think of these things as being transfluent, like a musical scale.
going up or down to infinity and the infinitesimal.
then all I have to keep track of is at what point it goes from a multiple, to a divisor.
Some people, because of education or occupation, are trained to only go up, or only down respectively.
If you think about the frequency of the explosions,
with respect to the volume of gas exiting during the exhaust part of the cycle
and the volume of tube this gas will occupy during the amount of time before the next gush comes out.
a resonance in this volume of the pipe will do nothing good for the engine cycle,
because it is post-exhaust.
It can either evacuate the chamber very quickly, or it can restrict such from occurring.
If either of these conditions exceed engine tolerances, it causes problems.
Resonance may help push the exhaust out the end of the tailpipe, and I guess in some abstract way it can help
with propulsion (pulsejet?)
but I would hardly consider that to be an "efficiency gain", when considering the eventual replacement
of rubber mounts, and weld-points.
Now, if we consider a resonance in the intake part of the engine,
perhaps the periodicity of pulses from the fuel pump,
with respect to the intakes of the cylinders
this could result in a decrease in restrictive flow losses from tank to engine
meaning less "load" on the fuel pump,
perhaps there is an RPM, which your fuel pump works more efficiently.
how much of the cars fuel usage is attributed to the pump? not much.....
But this does give futile credence to an ICE resonance discussion.
[Then I said to myself:
"self - you just said to them that resonance was a bad thing, then showed them a way that it could help!"
and myself said to me "No, you just got turned around at the alternator".]
the alternator!?!
This operates desirably at a self resonant frequency,. the manufacturer told us so.....
can we drive at an RPM, that our alternator operates the best at?
yes, when the A/C clutch is not engaged, you can generally notice a brightening of your dash lights
within a certain RPM range.
it is usually between 2 and 3,000 or so, when the secondary coil is fully saturated, and the belt is spinning at just the right speed.
Then we get to resonance in the tires/wheels....... let's not waste our time, its just Bad...
Now,. we can go through all of the systems within car, or motorcycle, or gocart, or lawnmower,
and find different scenarios where resonance may help or hinder operation.
But it is impossible for all of these frequencies to be resonant together.
you may have one, or another, at different rpms.
it all seems like a pointless argument, in general you don't want resonances in an ICE,
and if you did manage to achieve one that was helpful, you have to keep your vehicle at that RPM
to sustain the effect....
drive 55 Mph, and only on cold days.
you will get the best MPG
