| T O P I C R E V I E W |
| urquiola |
Posted - May 20 2010 : 11:26:20 AM
Hi!: as you all know, when Toyota presented the concept of air injection in exhaust port to improve Wankel performance, specially fuel economy, they added also a Reed Valve (RV) close to the trochoid surface in the peripheral intake port; peripheral intake with variable geometry intake manifold made Mazda win Le Mans endurance and fuel use race (-SAE Paper 920309 , Ritsuharu Shimizu et al.). Yanmar Diesel showed also that reed valves improved the partial load and low r.p.m. performance of their small charge-cooled rotaries (SAE Paper 720466 Kojiro Yamaoka & H. Tado), but I got a letter from David W. Garside, that developed the Norton series of Rotary engines, telling that reed valves do impair the high r.p.m. performance, an untoward fact for their engines. As street car engines don't work long times at high r.p.m., anything improving low rpm and partial load performance would be very good for the average driver. RVs do generate opening and closing extra-flows, like an hydraulic ram, that improve volumetric efficiency; also, by tilting the RV angle, you can induce any desired amount and direction of swirl inside the combustion chamber, thus regulating flame speed and engine emissions. I had the concept of installing an Husqvarna 500 cc 2-Stroke engine prismatic reed valve in a rotary with peripheral intake, to improve low speed torque, fuel economy and emissions. I send this note to see if there is anybody with the expertise and will to receive the torch of this concept, implement it and let us know the results. Regards, salud + |
| 15 L A T E S T R E P L I E S (Newest First) |
| urquiola |
Posted - Mar 25 2013 : 6:54:43 PM
Attached please find a graphic on the results of a RX8 Renesis engine with Peripheral Intake Porting, as received from rotaryeng.net, coming from Mazdatrix. Results look very interesting for an Airplane mounted Renesis, but the slightly reduced output that seems appearing in the low rpm end of functioning may not be so good in cars, at least in street cars, than in airplanes, again, Reed-Valve controlled PP data are missing, and a R-V may probably add to the lower rpm and part load results of PP, as it will act as an always adequately placed PP opening and closing in the admission stroke. Enjoy it!
Download Attachment:  RX8PP264a-Stock-RX8 data.jpg
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| urquiola |
Posted - Mar 22 2013 : 12:08:21 PM
Hi: please, have a look ak this: http://www.youtube.com/watch?v=m3pCLjHZmhM From the very old times of internal combustion engines, it was known that the lower the compression ratio of an engine is, the higher the exhaust gas temperatures are, this may have been one of reasons of the poor results of first Poppet Valves. Does this apply also to RCES? Is there a difference in actual compression ratio of a Wankel Engine, and geometrical compression ratio of an RCE, as in Two-Stroke engines? Salut + |
| urquiola |
Posted - Mar 20 2013 : 3:51:53 PM
Your proposals look pretty right, but in the lack of a Software able to simulate this, and also of the expertise for doing it, or not having a possibility of obtaining actual data about this experimental approach, I can't say yeah! or nay!. The people in www.rotaryeng.net seem having tested the Peripheral Intake Port-Side Exhaust in a modifyed Rx-8 Renesis engine, but as their main field of scope is RCEs in aviation, the performance of this arrangement in a car can be only estimated, both environments are quite different. Salut + |
| Aaron Cake |
Posted - Feb 03 2013 : 11:36:49 AM
Seems to me a peripheral Renesis is going to have the same overlap as a standard peripheral exhaust port 13B...and if it doesn't, then the side exhaust ports aren't going to be large enough to flow enough for the peripheral intake ports. |
| urquiola |
Posted - Feb 03 2013 : 10:38:44 AM
The men in www.rotaryeng.net said that if you put a Peripheral Port for intake in a RX-8 Renesis while preserving the Side Exhaust Porting, you have the best of all worlds, and an stable idling as in best 13B series engines. Just somebody trying the Reed-Valve in the Peripheral Port is missing, probably the Paul Lamar people are not going to test it, as their main field is Aircraft RCEs, not street car's RCEs. Mazda in their webpage said that their new engine, that will have a narrower Rotor and an enhanced eccentricity to improve torque at low rpm, and a brand new architechture, Renesis is not too different from previous 13Bs, just rotor weight is much less, side seal are scraper seals, and side exhaust ports include ceramic parts. I have told almost everything I know, I'm just waiting some feedback from actual experimentation on these concepts. Thanks, salut +. Wild winds are blowing! |
| urquiola |
Posted - Jan 01 2013 : 3:56:17 PM
About the subject of RCEs fuel economy, a book in German by Ulrich Ch. Knapp: "Wankel on the test bench" (Waxmann, 2006), page 135 contains a table that points that by 1976, fuel economy of Wankel and reciprocating engines was the same, and many improvements have been added to RCEs since then. Salut + |
| urquiola |
Posted - Jan 01 2013 : 1:33:42 PM
The articles by Ming-June Hsieh et al. about: "The intake and exhaust pipe effect on a Rotary Enegine performance" and "The numerical investigation on the performance of Rotary Enegine with leakage, different fuels and recess sizes", were finaly deleted from the SAE papers list, as authors failed in appearing to the meeting they were supposed to present their work, because of USA Visa problems, and if you don't attend the meeting, they don't publish the work. Hope we have again the oportunity to look at these very promising papers. Nice day! |
| urquiola |
Posted - Jan 01 2013 : 1:30:44 PM
You'll like it! There's another video, 3d of 4, about the non-Wankel Rotary Combustion Engine (Moto Turbine Radiale) that his inventor, the french Jean-Claud Lefeuvre, managed to build and have it working, and working well, very few can say this. See http://youtu.be/puqpf3wGHrw Happy New Year, salut + |
| urquiola |
Posted - Oct 07 2012 : 5:50:50 PM
Hi!: finally, it seems the e-tron will mount a 3-cylinder reciprocating engine as range extender. When you speak about Mazda SAE papers, you mean looking somewhere at Mazda website or at SAE? There are many SAE papers about RCEs, buying them all is a lot of money! In my last order to SAE, one of the most promising titles about the influence of intake and exhaust manifold features on RCE performances was out of print and still is, the SAE paper number for this article is listed in the Wikipedia Wankel engine main article. Salut + |
| Aaron Cake |
Posted - Sep 29 2012 : 10:29:34 AM
Have you looked through Mazda's SAE papers? There is an extensive collection relating to rotary porting because they've basically tried it all. I've not personally read them for years (last time was the early 2000s) though.
I can't seem to find a diagram of the e-tron's rotary but it may be a charge cooled design. "Single port" is an odd way of describging it. That may be down to the confusion of the person writing the report. |
| urquiola |
Posted - Sep 25 2012 : 6:41:31 PM
I mentioned the SAE paper 921444 on a Wankel engine with high-pressure recirculation of unburned gases. The engine in the paper, from Marcos Langeani in Chile, shares some features with those of Yamaha and Kawasaki I cited above in this forum. The Suzuki RE-5 engine had a peripheral port with the carburetor throttle near the epitrochoid surface, acting as said like some kind of a non-return valve for avoiding blow-back of exhaust gasses to the intake manifold, and also the RE-5 engine had two small round ports just for idle; the Norton engines had the throttle placed this way too. The Suzuki engine gave a life of more than 250'000 km by using the coating described in the Canada patents by Alfred Grazen along with Ferrotic apex seals. |
| urquiola |
Posted - Sep 25 2012 : 3:25:52 PM
Hello again!: I've just finished reading the SAE paper 950454 (Ritsuharu Shimizu et al) on characteristics of fuel economy and emissions of Side Exhaust Port RE. It seems that even with side exhaust plus side-intake porting, some EGR exists, but it can be better controlled this way. As pointed elsewhere, Harry Ricardo has shown in the 20's that for every 1% increase in EGR, you get 45º F of flame temperature reduction, and the highest the combustion temperatures, the higher the amount of NOx in exhaust is, so Exhaust Gas Recirculation may be good for reducing Nitrogen Oxides emissions. Some press news about the electric Audi e-tron car said that it had a single rotor, 250 cc Wankel RCE engined range extender unit, but it said it was a "Single port" RCE. Does it mean the port was used alternatively for intake and for exhaust? This is a new and interesting concept. Nice fall, Salut + |
| Aaron Cake |
Posted - Sep 15 2012 : 11:39:24 AM
Now that's an interesting design, I'll have to check that out. Two thinner horizontal peripheral intake ports controlled by valves. Depending on the shape of the exhaust port, overlap could be not much worse than the typical peripheral exhaust with side intake. Ultimately two small peripheral ports would be a compromise as the 2nd would have to be rather high up and into the compression stroke a little.
Mazda has all but eliminated overlap in the Renesis. I can't remember the exact figure, but it's very little.
Mazda alternately added and removed EGR several times in the production of the 13B. There is no EGR in the Renesis. Natural overlap means that EGR isn't necessary.
It's fairly obvious to see the the effects of too much EGR, causing charge dilution. Look at any aggressively ported rotary (bridge, j-bridge, semi-peripheral, peripheral) and the most obvious effect is the pulsing, rhythmic misfire in the idle. |
| urquiola |
Posted - Sep 07 2012 : 1:10:36 PM
The US patent number 3964448 (free download in Espacenet) describes the dual peripheral port system Yamaha used in its RZ201 motorcycle two-rotor liquid cooled 68 HP engine, one of the ports open or closes depending on the rpm and load of the engine, the motorcycle reported being very elastic, as delivering power from the bottom end of the engine speed. (Kawasaki X99 motorcycle's Wankel engine had some patented improvements too: US 3848574, and also another engine 3991722). In this patent you'll find references of other patents related to the subject, and Yamaha addresses, like Aaron Cake did, the issue of dead space and carry-over of exhaust gas into the admission stroke, a feature that in the early times of RCEs originated the so called "misfirings" or alternating cycles where the mixture incoming in the admission stroke ignited or not, with roughness of idle and poor emissions features of engines suffering this. I have the hunch that it's impossible in a Wankel Rotary Combustion Engine to fully eliminate some exhaust gas entering the admission stroke, but as long as the amount of Exhaust Gas Recirculation is kept under an appropriate level, somebody must have measured the top acceptable rate of EGR for a Wankel RCE, a little bit EGR can be even beneficial, and the Reed-Valve with a peripheral intake port may act as a variable timing intake, always giving the best possible filling of intake stroke or volumetric efficiency. Please try it! |
| urquiola |
Posted - Aug 13 2012 : 1:36:46 PM
The new Norton NRV588 motorcycle two rotor engine uses the same intake tubing length changing system as the Mazda that won the Le Mans race, Roton was developed by Brian Crighton from Norton, but it seems doubts exist about the activities of this brand in Australia, some info is at www.jpsnorton.com (Please don't consider smoking because of the connection of this name with tobacco industry, tobacco still kills!) |
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