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Discussion Starter #1 (Edited)
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

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

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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.
 

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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.
 

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… 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.
 

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Discussion Starter #6
… 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.
 

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Discussion Starter #7
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.
 

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Discussion Starter #8
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?).
 

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Anachronisms in the jet age....

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.
 

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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.
 

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Discussion Starter #11
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.
 

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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
 

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Discussion Starter #15
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.
 

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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.
 

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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.
 

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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.
 

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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.
 

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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.
 
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