New kind of rotary engine - hypnotic!


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There’s a painful high-pitched squeal in the video.

Very Cool!

I remember the excitement surrounding the Wankel engine when it was first introduced in production automobiles in the US, followed by their slow fade as various engineering issues made it clear they were not the right engine for a car.

I hope this story goes differently :smile:

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Hmmmm, interesting design. I also was thinking about the Wankel’s death from a bunch of teeny-tiny flaws and tendency to output a high rate of smog. This engine seems to solve a bunch of problems, and the design will clearly save a lot of weight from the typical construction methods. Yeah, if they can get enough people out there who know how to work on them, this thing might work.

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I saw something about this engine, like ten years ago or more. It’s older than me.

The video shows more detail than I’d seen before, so I can understand how it works now.

It seems to combine the disadvantages of both reciprocating and Wankel engines or rotary valves…

If you want to improve on the traditional piston engine it’s a good idea to lose the pistons if you can, which need to be accelerated to high speed and decelerated to a standstill several times a second… the Wankel pulled that off (no pun intended) brilliantly, but unfortunately the apex seals of the rotors are a weak point, and for whatever reasons fuel economy was poor; a huge disappointment given the relative elegance and apparent promise of the design.

Rotary valves seemed like a great idea too, eliminating the camshaft pushing against all those valve springs, but IIRC there are major hurdles with the sealing.

The large rotating seal in the orbital engine between the block and the head would appear to be a similar source of major potential issues… and it still has pistons.

Meh to internal combustion anyway; it’s stupid.


Reading one of the disadvantages—

Poor fuel consumption as the exhaust stream is enriched with unburned mixture and carbon monoxide. Acceleration and deceleration as in direct drive average driving conditions also affects fuel economy. Running the engine at a constant speed and load eliminates poor fuel consumption.[48]

suggests gasoline powered generator and electric drive to me, but perhaps a car isn’t a train…


Like the fact you need new apex seals every 100k miles…

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Obvious downsides: Lots of spinning mass and friction. The high rotating and oscillating mass means that changes in RPM will be slower than a traditional engine, and the plethora of surfaces rubbing against each other in creative ways will be a nightmare to lubricate properly, and will necessarily lower efficiency.

This design popped up on reddit today, and as far as innovative and potentially-useful engines go, it seems like a much stronger contender.


The Wikipedia article notes that it is being revived as a range-extender for electric vehicles, so you’re right there with the Mazda engineers :smile:

I feel like if hybrid tech came along in the 70’s we would see someone building an actual turbine based hybrid. I know Chrysler played with a turbine prototype for a while at one point. Of course if GM hadn’t wussed out, went the easy route, and designed the Volt to be gas generator and all electric drive it would have been a great platform for various engine/generator prototypes. It was nice when companies were willing to spend money on real R&D and not just chasing the next Prius.


Toyota introduces: The internal combustion shake flashlight!


Rotary engines’ rotating mass leads to bizarre gyroscopic effects. I suppose if you had two in opposition you could cancel it, but that seems like it would reduce simplicity.

Also, there’s no way that you’d get decent compression with the cylinders unsealed like that.


This reminds me of the old “V” engine idea:

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Looking at this thing, it seems like it would operate in a pretty narrow power band, which is what’s needed for a hybrid power train. The hybrid ICE is designed for maximum efficiency at a specific rpm.

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I’m glad I’m not the guy who has to design the bearings and gaskets for this carnival ride turned internal combustion engine. So many angles on the forces…


Like those wwi aircraft that would climb on every left turn and dive on every right turn?


I notice that the animation at 0:50 does not match the physical model.

The engine is actually rotating the engine block, so acceleration would probably be poor. Also notice that the motion of the piston is nearly opposite the axis of the drive shaft and this is achieved through what must be some extremely precise geometry that must also stand up to great physical stress. I see no reason the same engine could not use a right angle drive. Wrapping it around the driveshaft seems like it would only be essential in specific applications.

Really this is not a rotary engine, this is a radial engine with an elaborate linkage in the middle.


Jaguar had a turbine hybrid concept a while back. This thing popped up on Jalopnik a few months ago; it’s basically an air compressor run in reverse.

This engine is similar to those used in torpedoes.


Reminds me of this:

Initially, the left engine was a V-1650-23 with a gear reduction box
to allow the left propeller to turn opposite to the right propeller,
which was driven by the more conventional V-1650-25. In this arrangement
both propellers would turn upward as they approached the center wing,
which in theory would have allowed better single-engine control. This
proved not to be the case when the aircraft refused to become airborne
during its first flight attempt. After a month of work North American
engineers finally discovered that rotating the propellers to meet in the
center on their upward turn created sufficient drag to cancel out all
lift from the center wing section, one quarter of the aircraft’s total
wing surface area. The engines and propellers were then exchanged, with
their rotation meeting on the downward turn, and the problem was fully