The problem with the rotary combustion chamber removing valuable heat from the burn is built into the geometry of the machine. It is near the end of a long period of developement for rotaries and piston engines, starting years ago before high energy ignition systems, and super high pressure injection.



The need to bring the higher tech stuff to the product is based on public demand and government rules about emissions.



So, progress is slow in companies where output is small like Mazda. Suppose that the rotor housing was lined with ceramic, and instead of two plugs far apart, we just had two electrodes and a spark jumped from plug to plug a few hundred times per cycle? Do you think that would help?



If there is no fuel in the air entering the chamber, radiation from the hot rotor cannot expand that charge much at all, so VE goes up, just from moving the injector inside the chamber.



Picture is of the performance manometer on a home built flow bench. Easy to build.



Lynn E. Hanover



Injectors operating at 40 pounds atomize well, but an injector operating at 2,000 PSI makes a gas out of fuel, as well as adding some heat, to help cancel that heat removed by chamber area and shape. So that will be an improvement.



If that injector fired into a small chamber similar to the trailing plug chamber, and that chamber had a super spark plug and giant MSD like system lighting the fuel as it was injected, much of the burn will be under way before much heat loss to chamber shape could occur. Or the new 16-X injector location at 12 oclock and the stratified (rich) charge from the chamber to light the very lean mixture from the 12 oclock injector.



Then add in the ceramic coating on the rotor face to maintain a high temperature..........then add all of your ideas here:.....................................





Lynn E. Hanover

 

So I've been letting some ideas bounce around in my head for the last hour or so for upping VE. Ultimately, I'm just trying to adapt proven techniques for making piston engines more efficient and applying the equivalent to make rotaries better. The main thing that's buggin me is the side ports. Why aren't the ports on the rotor housing rather than the side plates? The charge as it is gets sucked into the intake, then suddenly comes out the port and has to make a 90 degree turn as the rotor smacks into it and pushes it towards the spark plugs. Then it does it all over again when it gets to the exhaust phase. Such a waste, and changing port locations would definitely make it a much more free flowing setup.



I'm also thinking about how to make the ignition more complete since all those unburned hydrocarbons no doubt take a toll on VE. I like the electrode idea since the voltage traveling through the combustion chamber would make an "effective spark plug" with a length equal to the distance between the two electrodes. On top of that, it's like having a bunch of tiny spark plugs go off in sequence which would help the burn tremendously. My only serious concern (that occurs to me in this daydreamy state of an ideal rotary engine) is how much voltage would be needed to fire the electricity across such a gap. I imagine the larger the gap, the more complete the burn but clearly there's a balance between voltage available and gap size.



I'll let the ideas keep bouncing around in here and I'll post again soon.

 

There you go.....more ideas, brainstorming............



The periphery port is by far the best from the volumetric efficiency point of view, but suffers because of the longer overlap period where exhaust and intake are connected. Thus the move to have both exhaust and intake port in the irons as in the Renesis engine and the coming 16X engine.



The engine responds well to turbocharging because of the excess energy left in the exhaust stream from the HC problem.



So if the fuel is withheld to the latest possible time in the cycle, so as to eliminate detonation, overboosting the engine could be the normal condition rather than the 9 second dyno pass. This would take the engine to the very edge of diesel like operation and thermal efficiency would improve. Something needed in the rotary.



The extreme high energy ignition system is here now and that would be a start. Just have the period of time the plugs stay in full arcing current flow would be required. This is going to be the norm in all cars soon, so it needs to be done.



Lynn E. Hanover



Picture is a 13B in an RV-6 airplane

 

This is the link for a pdf of the SAE article for any wanting a bit more info such as myself: http://www.rotarydevelopment.net/RotDev/Do...1790_Rotary.pdf



I'll be posting soon with more ideas once I've gotten them...having side ports still bugs me despite the fact it removes overlap. Maybe some research regarding trochoidal shapes will help...

 

So more ideas: with the renesis, they eliminated ALL overlap with the side ports which seems a tad silly. The 6 port design is a fantastic idea (especially if it was coupled to ITBs instead of just a whole bunch of valves in the intake) which adds time for a larger port opening, but the same idea could be applied to the exhaust ports. Currently it's like having vtec for the intake cam but not the exhaust cam which is obviously limiting, especially with an N/A application. I can't see overlap being a bad thing, at least at high revs. An auxiliary exhaust port could be the solution though I can only assume having 3 intake ports and 2 exhaust ports per rotor housing was thought to be a bit complex by mazda. Perhaps they feared that adding another port would mean more unburned oil would be scraped by the sides of the apex seals out the exhaust. However, at WOT, clearly fuel economy is not the issue. Similarly, it stands to reason that at times with such high rpms, a freeflowing setup is also more to the point. Peripheral auxiliary exhaust and intake ports perhaps? Then there is still the flexibility of having some fuel economy with the side port design, even when the secondary side intake ports open so the engine can get into the revs it prefers, but once you really want to get going, all bets are off and the peripheral ports open.



Another idea I've been playing with is putting the spark plugs/electrodes on solenoid actuators. Each time the spark plugs are about to fire, the solenoids pop the plugs into a central position in the combustion chamber. The end result is a more complete burn. Logistically, it could be done. Even the 9000rpm redline of a Renesis does not translate to being terribly quick for a solenoid that can snap up and down in a ten-thousandth of a second. I can't imagine oiling/sealing the mechanism being terribly hard either.



Thoughts?

 

the rx8 has no overlap just for emissions reasons.