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Aaron Cake
Administrator
Canada
6717 Posts |
 Posted - Jun 30 2012 : 10:55:52 AM
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Yeah, the swirl generators have been around for a long time and are even still sold under names like the "Tornado", "Fuel Genie" and others. There was some benefit in some cases with older carbureted vehicles as the swirl would mix the A/F mixture a bit better. However now it's really nothing but a scam. EFI manifolds are carefully designed for as smooth an air path as possible and to use effects like Helmholtz resonation to work with the pulses caused by opening and closing valves/ports to cram more air into other cylinders/rotors. Combine this with sequential timed injection and more and more engines going to direct injection with charge stratification and all those devices just do harm. Stratified charge engines like that in my 2000 Insight rely on the ECU knowing exactly the flow characteristics of the manifold so that the fuel delivery can be controlled precisely to generate the required rich and lean spots in the A/F charge.
Fuel heating on a carbureted vehicle could again be beneficial as it would lead to better atomization (though other issues as well like vapor lock). On an EFI vehicle we want the fuel as cold and as dense as possible (many vehicles are fitted with a fuel cooler, and they have been available on the performance aftermarket for a long time...fuel gets hot circulating through the system). Then the injectors are relied upon to control atomization. |
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urquiola
Apprentice
Spain
97 Posts |
Posted - Jul 01 2012 : 09:19:35 AM
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| Yes!: U'R really an expert!. The image I had about the resonation effect in the ICE's intake manifold was the hydraulic ram (In the field of resonators for speakers you may have a look at The Karlson homepage), and the engine that made Mazda win the le Mans 24 h race had, as discussed, a variable geometry intake tubing with a mechanism similar to the one in a trombone, ducts were lenghtened for high torque at low rpm, and were shortened for high power at high rpm, this kind of arrangement would be very well adapted to accept a Reed-Valve controlled Peripheral Intake Port with Side Exhaust Ports, that I keep on thinking may be a good approach for both the low rpm efficiency, the emissions, and the fuel economy issues of Wankel rotary engines; it's sad for me that no open data are available as far as I know, on such an arrangement (Peripheral Intake - Side Exhaust Porting) The fuel saving devices whose images I posted are from the 70's, when fuel injection was too expensive for use in common cars, today even an ultra cheap car as the Tata Nano uses multi-point Electronic Fuel Injection; it would be nice having installed in the Tata Nano car or in anyone similar, a small air cooled rotary engine, and also testing it with a single port control system as the one depicted in the article by R Abell on "Single valve ICE design and operation" (SAE Journal Oct 1923, pp 301-309, it's 14 U$ to download the whole issue at SAE.org ). One of the best engineered cars in the past century: the french Citroen GS, had intake manifold heating for reduced emissions and increased fuel economy, and there's no big difference in heating something in the intake manifold and heating the gasoline, but your remarks on this are right. If you want watching a video about a non-Wankel rotary engine that works, and it's difficult finding one that does, please have a look at http://dai.ly/aFvCa5 about the Moto Turbine Radiale. Thank U! Enjoy summer! Salut + |
Edited by - urquiola on Jan 01 2013 4:33:23 PM |
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Aaron Cake
Administrator
Canada
6717 Posts |
Posted - Jul 07 2012 : 10:44:45 AM
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I think there isn't much done with a peripheral intake and side exhaust mainly because the same overlap issues exist with peripheral exhaust and side intake. The only way to go to zero overlap is very specifically shaped side and exhaust ports, such as the Renesis.
Designing your own intake manifolds, you quickly learn about resonation and its effects. Which is one of the reasons I always find it funny when the muscle car aftermarket companies advertise their intake manifold as "operating between 2000RPM and 6000RPM". Well yeah, I guess they flow air, but you're only going to see efficient resonation at a few narrow RPM bands. |
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urquiola
Apprentice
Spain
97 Posts |
Posted - Jul 07 2012 : 10:47:21 PM
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| Hi!: I'd say that a Peripheral Intake Port with Side Exhaust Port offers an overlap with negligible negative effects and perhaps some positive effects in the actual use, and the much better Mean Effective Pressure of PP at high rpm has no rival in terms of engine efficiency, PP not so good at low rpm or under partial load, but a Reed-Valve can help a lot in preventing the back-flow of exhaust gases into the intake manifold, and will help maintaining an efficiency comparable to side intake porting at low rpm and under partial load of engine, SAE Paper 841017 by T Muroki, on "Recent Technical Developments in High-Power Rotary Engines at Mazda" and other papers, such as the pioneer 288A, by Walter G Froede "The NSU Wankel Rotating Combustion Engine", from a SAE Congres of Jan 9-13, 1961, all speak about the port shape issue, these references appear in www.rotaryengine.net, where I was redirected from a Russia site http://volnovoidvigatel.spb.ru/ (Google translator converts both russian alphabet and russian text into understandable english) there are papers pointing to a greater efficiency of Peripheral Ports of a Rectangular Shape over the Round Shaped Peripheral Ports, the Norton charge cooled rotor engines that had a very good fuel economy used a nearly Rectangular Port, some rounding of corners of rectangle and of intersection of intake duct with working chamber can be of great help as discussed, but a Rectangular Port would be ideal for installing a Reed-Valve such as the 500 cc 2-stroke single cylinder engine Husqvarna R-V previously depicted in a photo, also a Rectangular Port offers the opportunity of tilting the axis of intake mix flow not exactly paralel to the main dimension of working chamber, and this tilting can induce a controllable degree of swirl in the fuel / air mix, that is a factor that affects both completeness of combustion, roughness of combustion process, and exhaust emissions. Please, anybody find me somebody having the envy of testing this! |
Edited by - urquiola on Jan 01 2013 4:34:47 PM |
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urquiola
Apprentice
Spain
97 Posts |
Posted - Aug 13 2012 : 1:36:46 PM
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| 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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urquiola
Apprentice
Spain
97 Posts |
Posted - Sep 07 2012 : 1:10:36 PM
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| 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! |
Edited by - urquiola on Sep 07 2012 1:43:11 PM |
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Aaron Cake
Administrator
Canada
6717 Posts |
Posted - Sep 15 2012 : 11:39:24 AM
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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. |
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urquiola
Apprentice
Spain
97 Posts |
Posted - Sep 25 2012 : 3:25:52 PM
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| 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 + |
Edited by - urquiola on Sep 25 2012 6:42:12 PM |
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urquiola
Apprentice
Spain
97 Posts |
Posted - Sep 25 2012 : 6:41:31 PM
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| 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. |
Edited by - urquiola on Jan 01 2013 4:40:34 PM |
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Aaron Cake
Administrator
Canada
6717 Posts |
Posted - Sep 29 2012 : 10:29:34 AM
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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. |
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urquiola
Apprentice
Spain
97 Posts |
Posted - Oct 07 2012 : 5:50:50 PM
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| 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 + |
Edited by - urquiola on Jan 01 2013 4:43:50 PM |
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urquiola
Apprentice
Spain
97 Posts |
Posted - Jan 01 2013 : 1:30:44 PM
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| 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 + |
Edited by - urquiola on Jan 01 2013 4:23:52 PM |
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urquiola
Apprentice
Spain
97 Posts |
Posted - Jan 01 2013 : 1:33:42 PM
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The articles by Dun-Zen Jeng et al., from Taiwan, about: "The intake and exhaust pipe effect on a Rotary Engine performance", SAE 2013-32-9161,
and: "The numerical investigation on the performance of Rotary Engine with Leakage, different Fuels and Recess Sizes", SAE 2013-32-9160, have a very interesting content. Nice day! |
Edited by - urquiola on Oct 05 2014 8:22:55 PM |
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urquiola
Apprentice
Spain
97 Posts |
Posted - Jan 01 2013 : 3:56:17 PM
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| 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 + |
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urquiola
Apprentice
Spain
97 Posts |
Posted - Feb 03 2013 : 10:38:44 AM
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| 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! |
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Reed valve fitted peripheral intake port Wankel
