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Rotapower - The engine of the future

Engine test data


Data will be added soon . . .


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.


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