Moller invents compound rotary engine, in which the two rotors act in series instead of parallel, causing the first rotor to act like a super charger / turbo charger, compressing the air while being pushed by exhaust gases:

Link (http://www.foxbusiness.com/story/markets/industries/industrials/moller-international-achieves-breakthrough-rotary-engine-performance/)

Major increase in efficiency, cooler exhaust, and no need for a catalytic converter.

This engine looks like it would be great for the Volt. The only thing I would be concerned with is price. If the price premium is high, GM may exclude this engine as an option. I would like to know if GM has evaluated different internal combustion engine designs. There are definitely designs that are superior to the classic piston design. I can only guess that the piston design has remained, because it is the cheapest. If it wasn't, other engine designs would have replaced it.

I suspect this engine would be cheap, because it has very few parts and doesn't require a catalytic converter. It's ability to just spin at a constant rate without having to adjust its load makes it a perfect fit for a REEV.

Don't get too excited. This guy has been scamming venture capital for decades. His Skycar is a joke. However the staged rotary compressor idea sounds reasonable. Maybe he finally invented something worth while. I just doubt that it will amount to anything given the past record.

… no need for a catalytic converter.. ? NOX might be less because of separate compression and expansion chambers, but exhaust from any ICE contains HC and CO (in addition to NOX). How do you turn them to water and CO2? Claiming the engine meets tough California regulations without a cat converter makes it suspicious. Also, to make the compressed air feed effective you must make the feeder chamber displacement at least 1.5 times larger than the combustion chamber. This might be possible, but why bother? A simple turbo charger will do much better job.

… no need for a catalytic converter.. ? NOX might be less because of separate compression and expansion chambers, but exhaust from any ICE contains HC and CO (in addition to NOX). How do you turn them to water and CO2? Claiming the engine meets tough California regulations without a cat converter makes it suspicious.

Given that rotary engines generate most all their pollutants along the combustion chamber walls, it may be a simple case that the combustion chamber is lined with a catalyst.


Also, to make the compressed air feed effective you must make the feeder chamber displacement at least 1.5 times larger than the combustion chamber. This might be possible, but why bother? A simple turbo charger will do much better job.

In effect, I believe this 1st chamber is a combination of a super and turbo charger, as the "compressor" is pushed by both the main shaft and the exhaust gases. You are correct, that there might be simpler approaches, but this seems very efficient in the close grouping of the two, as evidenced by the higher efficiency rating and cooler exhaust gas.

Don't get too excited. This guy has been scamming venture capital for decades. His Skycar is a joke. However the staged rotary compressor idea sounds reasonable. Maybe he finally invented something worth while. I just doubt that it will amount to anything given the past record.

Ever since Moller started using rotary engines to power his flying car, he has actually been able to get the thing off the ground. His website has the videos. This recent breakthrough should make his vehicle even lighter / more powerful - I just wonder if he is willing to develop and test the control algorithms to keep the thing stable.

This link provides more insight into how the compound rotary motor works:

http://www.moller.com/rptechnology.htm

It sounds like they have a special coating in their combustion chamber that eliminates the need for a catalytic converter. This coating prevents "quenching" at the combustion chamber walls to get a more complete burn. Somehow, it also removes the need for liquid (oil) lubrication (cooler / more complete combustion?).

Don't get too excited. This guy has been scamming venture capital for decades. His Skycar is a joke...If I was trying to build a flying car, I certainly would'nt use internal combustion engines to drive the fans, I'd use turbines.
I saw the drawings on the link provided, but these were only external diagrams.
Also, Moller claims numerous patents on this engine, but does'nt provide the patent #'s.

It sounds like they have a special coating in their combustion chamber that eliminates the need for a catalytic converter. This coating prevents "quenching" at the combustion chamber walls to get a more complete burn. Somehow, it also removes the need for liquid (oil) lubrication (cooler / more complete combustion?).

Classic Moller. Make it sound like the real deal, but pretty fuzzy on the details. Don't ever expect to see any real public demonstrations of this engine. Like I said, he's been doing this stuff a long time and his only real accomplishment has been to keep himself employed.

If I was trying to build a flying car, I certainly would'nt use internal combustion engines to drive the fans, I'd use turbines.
I saw the drawings on the link provided, but these were only external diagrams.
Also, Moller claims numerous patents on this engine, but does'nt provide the patent #'s.

Turbines are very powerful and efficient, but they are also very large and heavy. If you are making a small vehicle, turbines' size and weight may be prohibitive.

If I was trying to build a flying car, I certainly would'nt use internal combustion engines to drive the fans, I'd use turbines.
I saw the drawings on the link provided, but these were only external diagrams.
Also, Moller claims numerous patents on this engine, but does'nt provide the patent #'s.

A simple patent search about Moller came up with:

US Patent 6325603 - Charged cooled rotary engine
http://www.patentstorm.us/patents/6325603.html

European Patent
http://www.freepatentsonline.com/EP1040259.html

Australian Patent
http://sec.edgar-online.com/2003/10/14/0001189619-03-000131/Section25.asp

Here is an SEC filing that lists all their patents, including the latest:

Link (http://sec.edgar-online.com/2002/12/11/0001189619-02-000047/Section14.asp)

Here are three more patent applications:

Link (http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=0&f=S&l=50&TERM1=moller+international&FIELD1=&co1=AND&TERM2=&FIELD2=&d=PG01)

I found this snippet in Moller's April 2008 Letter from the President:

"The Rotapower gen-set is unique in its ability to address the plug-in hybrid electric vehicle (PHEV) car market and both Moller International and Freedom Motors have been approached by hybrid car manufacturers and are participating in plans to put the Rotapower engine into volume production in a number of countries. I will have far more to say about this in my next newsletter."

If Moller was already talking to hybrid vehicle makers, then I am sure their compound rotary engine will be an instant success, as it is more powerful, 12 dB quieter, greatly reduced exhaust heat and greatly reduced emissions.

Wankel rotary engines have always been and will always be more inefficient than it's pistoned conterparts, just from it's fundamental design. It makes good power at a light weight, but consumes a lot of fuel to do so, and pollutes pretty badly. And i would be wary of Mollers design: Wankel rotaries historically have had problems when it comes to dealing with forced induction. My RX7 did. As did a lot of the turbo rotaries. And I'd be a little apprehensive about not having to oil the rotor housings...

IMO, if you want a very efficient conststant speed engine for the PEEV's, a small displacement (perhaps, 0.5, 0.75L?) two-cylinder two stroke diesel would be the best way to go.

Wankel rotary engines have always been and will always be more inefficient than it's pistoned conterparts, just from it's fundamental design. It makes good power at a light weight, but consumes a lot of fuel to do so, and pollutes pretty badly. And i would be wary of Mollers design: Wankel rotaries historically have had problems when it comes to dealing with forced induction. My RX7 did. As did a lot of the turbo rotaries. And I'd be a little apprehensive about not having to oil the rotor housings...

IMO, if you want a very efficient conststant speed engine for the PEEV's, a small displacement (perhaps, 0.5, 0.75L?) two-cylinder two stroke diesel would be the best way to go.

I understand the rotary inefficiencies to be centered around high power and varying power demands. I believe an "oversized" Wankel run at a constant, medium load is very efficient on will be much less troublesome too. They also have an advantage in being flex-fuel capable, too. While deisel isn't a bad idea, it is heavier, larger, and more expensive in volume compared to rotary. Size, efficiency, and cost are the 3 most important parameters for an EREV.

If Moller was already talking to hybrid vehicle makers, then I am sure their compound rotary engine will be an instant success, as it is more powerful, 12 dB quieter, greatly reduced exhaust heat and greatly reduced emissions.


Freedom motors has had hybrids shown on their website as one of their key potential markets for some time. Hopefully their newest engine is peforming as they say and they have done a good job marketing it to auto manufacturers. Time will tell, but I think could add a big boost to their Volt EREV powertrain performance with a purpose built engine. One of the elegant features of the EREV is that one size (of engine) fits many and 2 sizes could fit all.

I understand the rotary inefficiencies to be centered around high power and varying power demands. I believe an "oversized" Wankel run at a constant, medium load is very efficient on will be much less troublesome too. They also have an advantage in being flex-fuel capable, too. While deisel isn't a bad idea, it is heavier, larger, and more expensive in volume compared to rotary. Size, efficiency, and cost are the 3 most important parameters for an EREV.

Well you're not going to win in efficiency contest with a rotary in comparison to a diesel. They will cost more because they just pop more easily from forced induction. You automatically negate the size comparison if you want to go to an "oversized" rotary in comparison to a sub 1 liter 2 cylinder diesel. When running an engine for constant speed power, it's most efficient at WOT at peak torque, so you would not want to run a larger rotary at medium load. Rotaries tend to make their best torque higher in the RPM range, so it will have to run faster, while a two stroke diesel, even smaller ones, tend to run more slowly which will give you the benefits of a quieter running engine, and longevity, as diesels are well known for already, and rotaries are...not.
;)

Rotaries are great little engines if you need lots of power (speed) in a small package, but they pale in comparison to even gasoline piston engines in longevity and efficiency.

Jet engines are a rotary type and most are a lot older than me and most are still fully operational. I have outlived the piston engines of all my previous gasoline vehicles. In terms of mileage, the piston engines pale in comparison to the mileage of a jet engine.

Jet engines are a rotary type and most are a lot older than me and most are still fully operational. I have outlived the piston engines of all my previous gasoline vehicles. In terms of mileage, the piston engines pale in comparison to the mileage of a jet engine.

Jet engines =/= Wankel rotary engines. Wankels have fundamental problems and I know them quite intricately.

Jet engines =/= Wankel rotary engines. Wankels have fundamental problems and I know them quite intricately.

I'm sure I did not misread this generalization:

Rotaries are great little engines if you need lots of power (speed) in a small package, but they pale in comparison to even gasoline piston engines in longevity and efficiency.

So jet engines do not rotate? I must be mistaken. :D

There are also tiny little jet engines available that was even used by the flying man of the swiss alps:

http://www.youtube.com/watch?v=bEXxkWXncuo

JoeReal and Steel,

Wankel Engines and Turbine Engines are two separate entities, but they are similar in that neither are reciprocating motion engines, but, instead spin.

Freedom Motors has developed a version of the Wankel engine which they call the compound rotary engine, which has eliminated many of the problems of the Wankel engine:

- emissions - by lining the combustion chamber walls to prevent fuel-air quenching, they have achieved a more complete burn and by implementing features within the "cylinder" for air cooling, they have eliminated the burning of lubricants

- noise - the super / turbo charging "cylinder" harvests more of the energy of the combustion in a second expansion step, reducing the noise

- heat - the more complete burn within the "cylinder" and the two expansion steps convert more of the energy within the cylinder, so that less of the energy goes out the tailpipe

- power / weight - as good as Wankel engines were, the compound rotary engine is 30% more efficient, delivering more power for a given engine size

Thanks Jason and Steel.

If Moller's claims are true, the 93% reduction in noise, increased efficiency, cooler exhausts and reduced emissions, his new rotary engine could really revolutionize a lot of sectors of the vehicle industry, from aircraft to generators of electric vehicles.

Thanks Jason and Steel.

If Moller's claims are true, the 93% reduction in noise, increased efficiency, cooler exhausts and reduced emissions, his new rotary engine could really revolutionize a lot of sectors of the vehicle industry, from aircraft to generators of electric vehicles.

He's already planning to use it in his flying car, for which he is offering initially for $1 million a pop.

He's already planning to use it in his flying car, for which he is offering initially for $1 million a pop.

I've seen his car, his lab is in South Davis. I'm on the other side of the I-80 freeway. Anyway, at one time, he auctioned one of his flying cars at eBay. Starting price was $250,000. I lost track of it after pranksters began bidding furiously.

The flying car uses the old noisy turbo prop, about 5 of them. You can buy the car from the auction but then it will have to be tethered when using it because it wasn't approved by FAA...

I've seen his car, his lab is in South Davis. I'm on the other side of the I-80 freeway. Anyway, at one time, he auctioned one of his flying cars at eBay. Starting price was $250,000. I lost track of it after pranksters began bidding furiously.

The flying car uses the old noisy turbo prop, about 5 of them. You can buy the car from the auction but then it will have to be tethered when using it because it wasn't approved by FAA...

I've watched the video of the tethered turbo prop, and it was very loud. Imagine if it were 96% quieter, and much lighter, using the new compound rotary engines - he would have a real beast on his hands.

JoeReal and Steel,

Wankel Engines and Turbine Engines are two separate entities, but they are similar in that neither are reciprocating motion engines, but, instead spin.

Freedom Motors has developed a version of the Wankel engine which they call the compound rotary engine, which has eliminated many of the problems of the Wankel engine:

- emissions - by lining the combustion chamber walls to prevent fuel-air quenching, they have achieved a more complete burn and by implementing features within the "cylinder" for air cooling, they have eliminated the burning of lubricants

I suppose I'll have to see it to believe it.


- noise - the super / turbo charging "cylinder" harvests more of the energy of the combustion in a second expansion step, reducing the noise

- heat - the more complete burn within the "cylinder" and the two expansion steps convert more of the energy within the cylinder, so that less of the energy goes out the tailpipe

I dont see how this is any different than a standard turbocharger setup. The heat and expansion of the exhaust gasses drives the turbo to charge the incoming air. Unless this turbo/supercharging rotor is connected to the output shaft, it will be the same deal.



- power / weight - as good as Wankel engines were, the compound rotary engine is 30% more efficient, delivering more power for a given engine size

30% more efficient than a standard rotary, maybe. But even then, compare it to a 1.3 liter piston engine, and the piston engine will still be more efficient. It might be on par with a 2.6l piston engine, if that's how you want to calculate its displacement.

And from what I've read about this guy, he seems to have a lot of empty promises, so i'll take his "new design" over what mazda's been working on since the late 60's with a grain of salt. If I'm proven wrong, then I'll eat my humble pie but until then I'm not holding my breath.

The compound rotary engine uses one rotor for super / turbo charging and one rotor for combustion, so it is a combination of the two. All the design changes that I listed combine to produce all these performance improvement - you can look up the patents yourself.

The compound rotary engine uses one rotor for super / turbo charging and one rotor for combustion, so it is a combination of the two. All the design changes that I listed combine to produce all these performance improvement - you can look up the patents yourself.

I just find that idea silly. Any turbocharger or supercharger will do the exact same thing, except with a simpler design. Why walk around the world to get to the next town over?

Turbines are very powerful and efficient, but they are also very large and heavy. If you are making a small vehicle, turbines' size and weight may be prohibitive.

Rotary engines are incredibly heavy for their size. They're practically a solid block of metal, very few pockets or gaps. The basic keg of the 1.2 litre rotary I took out of an RX-7, about the size of a small microwave, has a mass of 81.65kg (about 180 lbs) and that's bare bones and dry without intake or exhaust manifolds, any accessories, any coolant or oil, etc.

The compound rotary engine uses one rotor for super / turbo charging and one rotor for combustion, so it is a combination of the two. All the design changes that I listed combine to produce all these performance improvement - you can look up the patents yourself.

That's extremely silly. A simple DEI box molded into the intake manifold of a rotary engine acts as a virtual supercharger, augmenting the pressure from the natural or turbo compressed intake charge by tuning the pressure pulses as they are drawn into the intake ports. NO moving parts nor exotic materials required. This has been around and in production since 1984.

edited for typo

That's extremely silly. A simple REI box molded into the intake manifold of a rotary engine acts as a virtual supercharger, augmenting the pressure from the natural or turbo compressed intake charge by tuning the pressure pulses as they are drawn into the intake ports. NO moving parts nor exotic materials required. This has been around and in production since 1984.

No matter how much you tune the intake / exhaust, you will never achieve the pressures of a super or turbo charger. This is how you achieve volumetric efficiencies higher than 100%, which drops the power / weight ratio substantially.

No matter how much you tune the intake / exhaust, you will never achieve the pressures of a super or turbo charger. This is how you achieve volumetric efficiencies higher than 100%, which drops the power / weight ratio substantially.

No kidding. That's why I mentioned how it acts as a virtual supercharger, augmenting the pressure from the natural or turbo compressed intake charge. And it does so extremely effectively, with no moving parts, special coatings, etc.

Easier methods to high milage without catalytic converter. Just take any gas engine and convert the liquid fuel to a vapor before inserting in the engine. Gives you about 100 mpg and almost as clean as natural gas. Already been done so risk is minimal.