The video talks of the CEO interview where he states that they have "reinvented the conrod" to remove first and second order harmonics.
Could it be as (relatively) simple as a cutout in the H beam for a type of tuned mass damper?
I'm definitely open to some speculation, as it would seem that it could be adapted to almost any engine.
Thoughts?
Re: Alfadan conrods
Posted: 18 Jul 2021, 04:22
by J.A.W.
Yeah, seems like a fairly big claim, esp' sans useful data.
A 30hp 2-cylinder test engine is a far cry from 325hp @ 5500rpm, as expected per the claim.
Another caution about 'hype' is to be found in the bio-blurb of the CEO,
wherein it is claimed that he:
"...headed R & D of the 1st miniature gas turbines used in military UAV's..."
But of course, mini turbo-jet manufacture for target drones & small planes - well pre-dates - him.
Yeah, seems like a fairly big claim, esp' sans useful data.
A 30hp 2-cylinder test engine is a far cry from 325hp @ 5500rpm, as expected per the claim.
Another caution about 'hype' is to be found in the bio-blurb of the CEO,
wherein it is claimed that he:
"...headed R & D of the 1st miniature gas turbines used in military UAV's..."
But of course, mini turbo-jet manufacture for target drones & small planes - well pre-dates - him.
Could it be as (relatively) simple as a cutout in the H beam for a type of tuned mass damper?
clearly not
the 'first and second order harmonics' (does the poster mean 1st/2nd order or 1st/2nd harmonics ?) are ....
time-varying inertia forces caused by fixed time-variations of velocities built-in to the fixed geometric cycle
a damper within that system won't cancel or significantly attenuate them ..... (dampers work on free vibrations)
some counterbalancer external or internal to that system could cancel them - by generating 'equal-and-opposite' forces
yes in principle this might be an active eg electromagnetic or electrostatic (ie piezoelectric) device ....
which might also act as a damper
a passive eg tuned mechanical counterbalancer device in the rod might be of some use - but is frequency-specific
TMDs mostly damp free higher-harmonic torsional vibrations of the crankshaft - unrelated to the topic matter
Could it be as (relatively) simple as a cutout in the H beam for a type of tuned mass damper?
clearly not
the 'first and second order harmonics' are ....
time-varying inertia forces caused by time-varying velocities built-in by the cyclic geometries
a damper within that system won't cancel or significantly attenuate them ..... (that's not what a damper does)
some counterbalancer external or internal to that system could cancel them - by generating 'equal-and-opposite' forces
yes in principle this could be an active eg electromagnetic or electrostatic (ie piezoelectric) device ....
which might also act as a damper
TMDs mostly damp higher-harmonic torsional vibrations of the crankshaft - unrelated to the topic matter
Could it be as (relatively) simple as a cutout in the H beam for a type of tuned mass damper?
clearly not
the 'first and second order harmonics' are ....
time-varying inertia forces caused by time-varying velocities built-in by the cyclic geometries
a damper within that system won't cancel or significantly attenuate them ..... (that's not what a damper does)
some counterbalancer external or internal to that system could cancel them - by generating 'equal-and-opposite' forces
yes in principle this could be an active eg electromagnetic or electrostatic (ie piezoelectric) device ....
which might also act as a damper
TMDs mostly damp higher-harmonic torsional vibrations of the crankshaft - unrelated to the topic matter
What abuot some sort of compression of the rod?
Re: Alfadan conrods
Posted: 18 Jul 2021, 23:35
by gruntguru
AlfaDan's "BIG SECRET" is skotch yokes replacing the con rods. (Not a new idea - its hundreds of years old.) This eliminates 2nd order imbalance which Alfadan erroneously claims is the factor which limits cylinder size in inline fours. This concept is doomed to failure. https://patents.google.com/patent/US103 ... US10378578
Re: Alfadan conrods
Posted: 19 Jul 2021, 00:36
by Tommy Cookers
and there's always the Lanchester Rhombic drive ......
AlfaDan's "BIG SECRET" is skotch yokes replacing the con rods. (Not a new idea - its hundreds of years old.) This eliminates 2nd order imbalance which Alfadan erroneously claims is the factor which limits cylinder size in inline fours. This concept is doomed to failure. https://patents.google.com/patent/US103 ... US10378578
Looks like a neat concept actually. Can you tell us why it's doomed? The large sliding surface area robs power/heats up/deflects? Can you please be more specific?
Re: Alfadan conrods
Posted: 19 Jul 2021, 02:08
by Hoffman900
I agree with the doomed to failure.
As an aside, Aluminum connecting rods are interesting in that are popular in power adder drag racing classes. The slight give in their design saves bearings. Service intervals are short, but that’s not a problem for them.
As an aside, Aluminum connecting rods are interesting in that are popular in power adder drag racing classes. The slight give in their design saves bearings. Service intervals are short, but that’s not a problem for them.
Why doomed? Is there a clear engineering reason that you can share please?
AlfaDan's "BIG SECRET" is skotch yokes replacing the con rods. (Not a new idea - its hundreds of years old.) This eliminates 2nd order imbalance which Alfadan erroneously claims is the factor which limits cylinder size in inline fours. This concept is doomed to failure. https://patents.google.com/patent/US103 ... US10378578
Looks like a neat concept actually. Can you tell us why it's doomed? The large sliding surface area robs power/heats up/deflects? Can you please be more specific?
In this case the "idea" seems to be based on the premise that 4 cyl engine displacement is limited by secondary imbalance and Alfadan has a mechanical solution. The reality is that secondary imbalance is easily cancelled with balance shafts and the real limits are mainly inertia torque and the fact that thermal efficiency for SI engines peaks around 300 cc/cylinder (this has probably increased since Taylor's time) and falls steadily as cylinder size grows.
Many have tried to implement the Scotch Yoke in piston engines - and failed. Lots of issues with strength, lubrication etc and at the end of the day there is no real benefit.