Originally Posted by robrecht

Thanks for the explanation, but I don't quite understand what you mean by driving in a "higher" gear improving fuel economy. Did you mean "lower" gear?

Also, generally speaking, is there a greater increase in efficiency when turbocharging a Diesel as opposed to a gasoline engine?

Originally Posted by globi (Post 2518837)

I meant driving in 5th gear vs 3rd gear.


Diesel don't deal with detonation, which allows higher pressure ratios and thus higher efficiencies.
Also, Diesel engines usually have a low power to weight ratio. Thus if they were not turbocharged, a diesel engine without turbocharger would need to be bigger in order to generate the same amount of power. This again would increase engine weight and with it vehicle weight, which again would reduce the overall efficiency of the vehicle and worsen fuel economy.

Originally Posted by RotoRocket (Post 2523842)

How serious or viable is this in terms of making into something backed by Mazda? In other words, would it void one's warranty, or would Mazda even offer it as a factory build?

Also, what effect would it have on reliability/durability?

I understand their reluctant to discuss specifics because of pending patent claims, but is this closer or further to reality within the near future?

Thanks.

Originally Posted by Floyd (Post 2524330)

I'd say that depends on the success of the final product from Moller. If it really kicks ass then Mazda may just take notice of it. Infact if we continue to discuss it here there is an even greater chance that they will.

If this design does create a signifigant jump in efficency then I don't see why Mazda wouldn't be interested.

If this were the case then I would see perhaps Mazda making Moller an offer to buy the rights to the technology and Moller (being smaller and in need of funds) accepting.

All in all it is not impossible, just not likely any time soon though...

Originally Posted by RotoRocket (Post 2523842)

How serious or viable is this in terms of making into something backed by Mazda? In other words, would it void one's warranty ...

Originally Posted by robrecht (Post 2524500)

It's not a DIY job but, if it were, yes, it would definitely void your warranty.

Originally Posted by rotarygod (Post 2467328)

Of course it's quieter. The compound turbocharger/rotor is absorbing lots of energy. Sound is a form of energy. A turbo quiets an engine down considerably and sound can actually pass straight through it quite easily. With this arrangement, the sound of the exhaust leaving the power rotor is never opened to the outside world. It is always hidden somehow behind the closed ports of another rotor's chamber. I'd be willing to be it would require very little muffling. However I'm also pretty sure that enough heat is lost in the process that cat lightoff would be pretty difficult to do.

Originally Posted by rotapower.net (Post 3918656)

Emissions

April 29, 2009

The following is a reply to a question put to inventor Dr Paul Moller by Peter Mustafa asking why it is the Rotapower enjoys such low emissions.

We have shown toxic emissions (NOx, HC, CO) levels below ambient conditions in some cities during certain periods.

The reason our engine is so clean is partly explained in my Emissions Paper (9913).

To reiterate I will describe the reason as follows:

The rotary engine has no valves, which allows the engine to run with a very lean mixture (lots of excess air). A lean mixture burns slower and is still burning as it leaves the engine. This can burn the valves and is why small engines like lawn mowers run “rich” (the opposite of lean) to save their low cost valves. Now one of the problems with a lean mixture is that it can be hard to ignite. Again, our engine uses a charge-cooled rotor rather than oil-cooling it. This results in a rotor surface temperature of over 800 degrees F, versus 350 degrees F for a Mazda oil-cooled rotor. In addition, because of the charge (fuel/air mixture) being pre-heated to 200 degrees (and cooling the rotor in the process) the mixture at the point of ignition is much hotter and easier to be ignited despite being very lean.

With all the excess oxygen in the mixture there is very little hydrocarbons (HC) and carbon monoxide (CO) production. The NOx is low because the excess air keeps the final peak combustion temperature lower even though the average combustion temperature is higher. NOx is formed when combustion temperature exceeds a certain peak.

The above explains the toxic emissions, but for particulates the answer is somewhat different. Particulates result directly from the level of fuel particle size. For example, diesel engines, which are fuel injected, previously used 10,000 psi injection pressure or lower and as a result we saw a black particle smoke. Diesel's are now approaching 30,000 psi and the particulates have visually disappeared because the fuel droplet size is so much smaller. A gasoline engine, once it is warmed up—which takes some time, does not produce particulates because the fuel is vaporized (no droplets). Again, our Rotapower engine heats the air immediately since it cools the rotor and we have very little particulates even at startup.

There are many other factors involved (like exhaust gas re-circulation) but the above are the main differences in why our engines produce so much less emissions. CO 2 emissions are governed by specific fuel consumption and that benefit will be seen in our compound rotary engine.