The Revetec engine was first mentioned on The Kneeslider over 3 years ago and there’s been considerable progress since that time, the engine has been developed in many more configurations, as shown above, and in testing they’ve found it to have very high efficiency. Several of these could be adapted for motorcycle use, they have an X4 running in a rear engine trike.
Interesting engineering and if you’re into engine technology, you should stop by their website and see what they’re doing. Cool.
Link: Revetec
JR says
Nice!
ooooo yeah I wonder what a boxer 8 would sound like! Not to mention an X8…
I like the idea of being able to reduce piston stroke and actually gain torque! More torque please!
hoyt says
What a surprise…another engineering marvel from the southeastern hemisphere
WRXr says
If the main advantage is dwell and more complete combustion resulting in greater efficiency, please let’s see it as a diesel.
That boxer four as a diesel in a Goldwing would make a interesting tourer. Big torque with a range of???
todd says
Sweet, they’re building it to fit a VW transaxle. Maybe I can get one to put in my bug or my Vanagon. I wonder how it compares, a stock VW bug-trike will also lift the front wheels at 1/4 throttle take-offs.
-todd
Mr. Tanshanomi says
38.6% is “very high” efficiency? That’s lower than direct injection turbo-diesels already in production. I am still trying to figure out what clear advantage such a radical design offers. Different isn’t always better. Sometimes, it’s just different.
Spartandude says
@ Mr. Tanshanomi. 38.6% is very high for a gasoline engine. Diesels operate much higher typically, and produce more nitrates of oxygen (urea injection works pretty well though).
I am missing something on this design…what is balancing the pistons? Normally the crank shaft is weighted opposite of the piston to offset the momentum, boxer engines have piston moving in opposing directions, but this one has a linear to rotational transfer (crank analogue) that is rotationally symmetrical, while the paired pistons entire weight is oscillating independent of any counter weight that I can see. Sure one could tailor this to have minimal vibration at a given RPM due to mass damping of the engine, but at some point the piston forcing function’s frequency will match the system’s natural frequency and you will get the mother of all shaking with her daughters showing up at the overtone harmonics. I would love to find out how this is worked around. Anybody? – Peace.
Nicolas says
” function’s frequency will match the system’s natural frequency ” : well, maybe Reveted was originally looking for the way to quickly disassemble some VW trikes, bugs, vanagons and others … like the viagra or the micro-wave, some spectacular inventions are just the result of a failing experiment 😉
That’s a pretty cool and mechanically elegant invention, tough
Spartandude says
Update: I think I may have found the balancing mechanism. In the exploded view of an X engine on their website there are two shafts in a housing on top of the engine that are linked to the primary gear and go seemingly nowhere. Maybe each of these shafts would be weighted to counteract one of the pistons and offset the vibrations. Oh wait that would impose more vibrations out of axis to the pistons, unless they also balance out each others “overdamped” condition (look up balancing of steam locomotive engines). Hmm…back to the drawing board. – Peace
todd says
Balancing? This is where the “low RPM” comes in handy.
Since each geared flywheel/crank web is counter rotating they can have weights to counter the pistons. At 90 degrees the counter rotating would allow them to cancel each other as well. There would still be a rocking couple at the center of the two flywheels.
-todd
Spartandude says
@ todd,
Thanks for the reply, but the cranks can’t be weighted as there are three piston cycles per one crank revolution. This would mean that a weight offsetting the piston on one cycle would be neutralized by the other three lobe’s weight (thats what I meant by rotationally symetrical).
Possible on the low RPM though.
Spartandude says
Okay, I solved the balance equations with two pairs of dynamic balancing rods. These rods could neutralize their off axis vibration with one pair cancelling out the X and vice versa for the Y forcing function of the pistons. I haven’t figured out the equations for a single pair of balancing rods, but hopefully this will let me stop obsessing over this. – peace
todd says
Right, forgot the whole 3-lobe crank (“trilobate”) thing. I guess the “low RPM” still stands then.
This might be patentable but… One could always have a simple crankshaft (driving nothing) in the center of the trilobates that would allow the pistons to oscillate in opposition. They would then balance each other out. You would only add the small amount of friction in the rods and a small rocking couple in the off-set of the pistons.
-todd
Spartandude says
It actually was patented (look up tri-lobe engine on freepatents.com). A company called tritech also had some patents on the arrangement of the pistons, but they seem to be in a financial pickle. Couldn’t find the balance issue in the patents though.
I took another look at the x engine and saw that the pistons are in sync vertically. This would eliminate the x direction viabration and the rotating shafts on top could balance the y axis vibration while also offsetting each others rotational moment. One could also have only one top shaft (also used for the alternator) and have the drive shaft rotate at the same frequency as the pistons and these would cancel each others rotational moment.
I want one…anyone see a price tag on these yet?-peace.