You May Not Like It But this Is What Peak Combustion Technology Looks Like - Rotary Vane Engine

When you think of a rotary engine you probably think of a wankel engine, the kind of engine Mazda used to put in its coolest cars back in the day. They also recently put it in the MX30 REV, but this is some sort of plug-in-hybrid thing where the rotary engine performs the most humiliating task imaginable, it's a range extender.

Now the important thing about the Wankel is that it was a success in terms of power-to-weight ratio and smoothness in terms of everything else it was a failure. Fuel economy, emissions, low rpm torque, longevity, it really didn’t do any of these things well. It was and still is a very fun and very exciting engine so we’re going to call it a beautiful failure

A rotary engine is inherently superior in this regard because we need the output from the engine to be rotation. So that we can connect the engine to the transmission and the wheels, both of which are rotation. So if the internals of the engine are already based on rotation like the rest of the vehicle then we completely eliminate many problems, many parts and a lot of volume and mass.

This is why, according to both physics and common sense the ultimate internal combustion engine should be a rotary engine. But it should not be a wankel. It should be a rotary vane engine.

We essentially have a circle rotating inside an ellipse and we have four vanes extending in and out of the housing. As the vanes rotate they change the volume of the spaces they create.

We have air coming in through the intake ports. As the vane rotates it pushes the air into an ever smaller space which of course compresses the air.

When the air is fully compressed we add the fuel. And then we use a spark to ignite the air and fuel mixture. As the combusting mixture expands it pushes on the vane which rotates the internal circular rotor assembly creating rotational torque output. As the vane rotates further it pushes the exhaust out throught the exhaust port.

We have four combustion events for one full 360 degree rotation of the circular rotor.

In a wankel, we have one combustion event for one full rotation of the rotor and three rotations of the eccentric shaft.

In a traditional four-stroke piston engine we need 2 full rotation or 720 degrees of crankshaft rotation for just 1 combustion event.

This means that the rotary vane engine significantly outpowers both the Wankel and the traditional. But high power is just one of the features. It’s just one item on the list of benefits.

Just like a Wankel engine the vane engine doesn’t need a cylinder head, crankshaft or rod and there’s no reciprocation. So we have a very powerful, very lightweight, very smooth and very compact engine compared to a piston engine. But the vane is even more simple and it’s even smoother than a wankel.

Another benefit is that the vane engine isn’t just a powerhouse it is a torque monster and far better suited to creating massive low rpm torque than a piston or a rotary engine. In this regard too it’s very similar to an electric motor.

We have two things that both the Wankel and the piston engine can only dream off. A giant and a constant lever arm. And our combustion force acting right at the end of that lever arm for maximum torque. The large distance from the vane which receives the combustion pressure and the center of the rotor where the torque output is means that even a small engine with a small rotor will have a very large lever arm and massive torque output. And this lever arm is constantly there, it does not move or change it’s position in relation to the combustion pressure force. And it is constantly present in the same position throughout the entire progression of the combustion event. This leads to a long-lasting and very broad torque spike throughout the entirety of the combustion event. And remember we don’t have to wait for 450 degrees of rotation for another combustion event. In a vane engine, the end of one combustion stroke is immediately followed by the beginning of another. We need a four-cylinder piston engine to achieve the effect of a single-vane rotor.

A special thank you to my patrons:
Daniel
Pepe
Brian Alvarez
Peter Della Flora
Dave Westwood
Joe C
Zwoa Meda Beda
Toma Marini
Cole Philips

#d4a #rotary #rotaryvane

[RobDahm]

What if I stalk myself and post novel length comments here?? 😂😂

[drubradley]

I agree.. but I have to mention, I am one of those people you mentioned who has spent almost 22 years designing a vane powerplant.. There is well over 70 iterations on my design table and shelves. Most of them run, but the one problem that I run into and many others must cross, is the pressure relief on the back sides of each vane. If it is only air behind the vanes, that is okay, and helps keep the vanes outwards in addition to the rotational forces that naturally fling the vanes outwards. But, once you start to collect any liquids, behind the vanes, that is where me and so many others run into crashes, or failure of the machine. We have tried to vent this trapping system to both the intake side to suck any liquids out of on the exhaust side to be pushed out from the linear motion of the vanes telescopic travel in a pumping action... Even tried to just vent these trapping areas to external areas, for collection just to try to get past the issue... I have tried through holes vents long wise in the vanes themselves to allow the trapped liquids to relieve into the front side of the vanes for additional lubrication on the walls, and likewise on the aft side of the vanes in efforts to lubricate the next following vane.... In either of those, we get hovering of the vanes at higher rpms as the edge is trying to either collect/scrape/scoop up the previously laid oil/fuel and grit and results in HP and rpm loss, and after extended periods of endurance runs, hammering effect of the walls, does what we call "catipillar walling" of harmonic wearing in a sign wave and that creates a nasty problem that compounds on itself to destruction very quickly....

These units are so much fun, but I am personally burnt out.. the math mathematics that goes into the volume of the wedges to intake/exhaust to the dimensions of the vanes length, width, height and or length to thickness issue. Based on over 200 material iterations in some base models, and discover some work great some not, but it just keeps the battle of wear factor to life expectancy of the vanes and housing wall(s).. the saving grace is the ease of machining, as compared to the exceptionally tight tolerance of the Wankle housing to rotor dimensions to aid in prevention wedging or crashing.. these vane motors are pretty forgiving in manufacturing... Allot of work, (as you stated) is still needed by somebody who has more money then me.. I am just a guy in a machine shop playing part time on these, in fact, I haven't touched them in about a year or so...

I am not saying anything you said is wrong, but more over, agreeing with you, there is allot of potential for these designs, but somebody who has more money then me can play with more specialized materials / alloys, and simulation software better then mine to hone every bit of active and passive friction out of the entire rotational cycle while incorporating balance as a whole..

Oh, and another crazy issue, leeching, from a combusted chamber, leeching under the wiping edge to the yet not combusted air/fuel ... With a mass damper damage happens in the idea to just carry the rotation on over past the preignition leeched chamber with bent vanes, or snapped axle shaft or ruptured wall.. that is always a fun day and loud too... With out a flywheel aid to dampen things out harmonically, the motors rattle themselves into shavings and scrape themselves to death.

Smaller power tools vane pumps are stable, but the moment they step up to combustion, a whole other character of issues happens... Which is what the one photo of the multi-vane rotor was trying to deal with I think it was a (20 vane rotor) also trying even number of vanes and odd number of vanes all trying to calm down the harmonics or vibrations that rattle these into destruction... I wish more people could put more effort and money into this, venture..

The biggest unit I have that is still working is 5 inches, and offer (0.2 HP) @15, 000 rpm .and is on a bicycle and geared super low and allot of backfiring from unspent fuel but does work just not very good but is on the threshold of not ripping itself apart.. Maybe this winter, I can get back on these

[MrPJunior]

as an engineer, i see problems with it:
1. wane reliability
2. lubrication
3. crosschamber isolation

[AaronMartinColby]

I think that the REAL solution is not to eliminate reciprocation, but eliminate rotation. Instead of wheels, we should have large legs that hammer the car down the road.

[TheAirplaneDriver]

Excellent video! I’m a mechanical engineer and have been involved in compressors and gas pumping equipment for use in chemical plants and oil refineries for 50 years. The achilles heel for vane pumps is not just vane wear against the compression housing, but also vane blade failure, spring fatigue, and the buildup of combustion byproducts and sludge in the vane slots on the rotor causing the vanes to stick.

Though not a thing for automotive use, vane compressors are still used in industry with some regularity and many attempts have been made to make them more reliable. But still, this technology takes a backseat to more reliable designs - with all their weaknesses - such as reciprocating compressors.

Even in aviation, most light aircraft use vane style vacuum pumps to generate vacuum for flight instruments. But, they too are quite prone to failure which requires two pumps to be installed for backup.

Someone may solve these problems with materials and reciprocating vane design improvements, but it is still on the horizon and not here yet.

[jaspurr]

"What if we push fluid into a pump, and make it explode too"-type-engine

I love it

[toofnlazzy]

Rx7 owner: the apex seals were a major problem in a wankel.

Vane engine: "hold my beer"

[Badge]

Your video caught my attention as I designed this exact engine 40 years ago while in high school. I grew up on a farm and we fixed everything and I knew every part in every engine we had. I liked the idea of the rotary engines and first is how to lub it. I tossed that aside and though do it like a two stroke. Ok that will work now how long will it last. After seeing OIL pumps fail that just pumps oil I began to have doubts that it would last any time. Now the emissions have be be cleaned up. Best is cylinder and odd shaped combustion chambers do not burn well in the wedges and they are just there. I lost interest in it and have lost my original drawings somewhere in the many places I have been. Thanks for the video.

[KevinJones-rg]

For a few minutes I was thinking this was a beautifully simple concept. Then the issues of lubrication and stresses on the vanes brought me back to earth. Nice mental exercise.

[Surestick]

There are three things to look for in any new miracle engine technology:
1- How is it cooled.
2- How is it sealed.
3- How is it lubricated.
Cooling this thing would be similar to a Wankle so not that big an issue.
Sealing this thing would likely be exponentially more difficult than with a Wankle which already has issues with apex seals. In addition to the issues faced by Wankels the amount of travel of the vanes at any significant RPM would likely get into the same issues as seen with early valve springs.
Lubrication would require some oil burning (bad for emmisions) and lubrication of the sliding vanes under high temperature and pressure.

[WolfVidya]

The Wankel engine has one crown the sliding vane hasn't taken yet: It worked to the point it reached production level to be used on real life, day to day applications.

[alistairmcmillan]

About 2 decades ago as a mechanical design draftsman with equivalent of 2nd year mech eng and also obsessed with the idea of a better ICE with lower weight, smoother operation and torque, I came up with several iterations (unfortunately only in digital form, no contacts, money or time to do what I wanted to do which was get a prototype built). There were some differences between mine and the design shown in this video. One being that the rotor isn’t circular but elliptical and the vanes in mine were located not in the spinning rotor but in the casing which solves quite a few problems and allows for a sturdier, precision cam-operated vane with lighter sliding seals against the rotor. Also, the exhaust gases vent through ports that open in the side of the housing, ensuring almost complete venting of exhaust gases.

One problem with this type of engine is that combustion always occurs in the same location, and the housing will get extremely hot there, but modern materials and cooling systems should cope.

I’d also love to see this type of engine happen. I honestly think that this is one of the many things that humanity has failed to exploit to our advantage.

[kentkoeninger]

I checked with my step-son who is highly regarded in the field of engine design. He agreed with the multiple potential benefits. He also agreed with you flagging the seals as the unsolved problem.

He said no-contact gas seals using ceramic piezo-electric actuators in jet engines seal a constant-size gap. That is trivial compared to sealing the variable-diameter vanes. It would be difficult to extend the vanes outward to a consistent length at a um tolerances. In addition, they would have to do this while being exposed to both the full heat of combustion and the full speed of the rotor.

I learned a lot from this episode. Keep'm com'n.

[KantiDono]

Actually, the best type of internal combustion engine is neither a Wankel nor a Rotary Vane engine. It's a Turbine engine, for all the reasons you described.
A Rotary Vane engine is interesting, but I'm wondering what the wear characteristics would be like. The vane being a long lever arm is good for torque, but it also means it will need to resist a lot of side-load forces while still moving smoothly in and out to maintain the seal with the sidewall. They work fine for air tools because the pressurized air is providing a steady pressure with a low impact compared to the shock front of a fuel detonation. No contact seals work for Turbines because the blades aren't moving in and out. There's no travel, just thermal expansion to compensate for. It's not feasible to maintain a gap like that while the vanes are moving in and out at the rotation speed of the engine.

[raptor]

17:07 When you said "Roy Hartfield", that caught me off-guard for a second - because I'm currently a student at Auburn University, and I thought "wait, THAT Dr. Hartfield??" Sure enough, it's the same guy, and I walk past his office every day! He's one of the aerospace engineering professors in Davis Hall. If you want to ask him some questions, perhaps you could reply with them here and I can stop by his office to pass them on in-person to get his response!

[charleslowe]

Well, this is the first mention of this type engine I have seen. I am all for this mechanical technology.

[mrkosmos]

The Vane engine, now with 33% more apex seals flying out of your exhaust

[future]

"Things tend to not exist and not be used.... before they are.... existing... and used...." This is the kind of wisdom that brings me back to d4a, thank you 😂

[NightmareKato]

As a machinist, I have to say this: this design is neat on paper but would absolutely grenade itself. Anytime you add a spring loaded dragon into a rotating assembly, the centripetal forces will cause problems, in addition to the fact that there is not enough structural material to keep those fins from bending themselves out of the central assembly.

It is wildly impractical.

[izzysykopth]

I love your channel and you are so gifted at helping the average mechanic understand the concepts of so many different designs that I can’t help but think you could design something to overcome the obstacles to the vane engine…