I've recently found out about a Wankel Engine, much more sensible engine design then the usual engines we are used to. This is something most people are unaware of.
Most of us are used to common 4-stroke cylinder engines found in most today's cars. One such engine consists of a cylinder body, piston that moves up and down, and a connecting rod that connects the piston with the crankshaft, turning linear movement into a rotational. Of course there are much more elements to it then these but these are basics. In four strokes of the engine air and fuel are inducted, compressed, ignited and exhausted out. Here is the schematic view.
Four stroke engine work diagram
These are the most widely spread engines today although they have many disadvantages. A lot of moving parts which makes them complicated to build and maintain. It also adds to the weight of the engine. Due to transformation of linear to rotational movement noticeable vibrations occur and the limit is imposed on maximum RPM (so called redline). Efficiency of such engines is normally only around 30%, which means that 70% of power is lost during one combustion cycle to other sources like heat. That means that your 100hp car in reality has a 300hp capable engine. Add transmission and drive train losses which are usually about 20% and you see how much power (and fuel) is wasted.
Naturally if someone could solve this efficiency problem connected with engine design they would become the richest man in the world.
The Wankel Engine
A German inventor called Felix Wankel first proposed a design of an ultra simple and efficient engine which was called after him the Wankel Engine. Wankel engine uses rotor instead of a pistons which allow it to deliver power without vibration in much higher RPMs. The design is so simple and brilliant. Here is how it works.
Wankel engine work cycle
In the basic single-rotor Wankel engine, the oval-like housing surrounds a three-sided rotor. The central drive shaft, also called an eccentric shaft or E-shaft, passes through the center of the rotor and is supported by bearings. The rotor both rotates around an offset lobe (crank) on the E-shaft and makes orbital revolutions around the central shaft. Seals at the corners of the rotor seal against the periphery of the housing, dividing it into three moving combustion chambers. Fixed gears mounted on each side of the housing engage with ring gears attached to the rotor to ensure the proper orientation as the rotor moves.
Wankel engines deliver much more power output then a cylinder engine of same displacement. They are also much lighter and since they consist of only three or four moving parts they are much easier to build and maintain. In case of engine problems in combustion, the Wankel Engine would only slowly seize to work while in a piston based design engine a possible destruction of inner parts of the engine is likely.
Wankel engines just start to have a wide recognition with car manufacturers. Only Mazda actively uses Wankel engines and their model RX-8 is best known for it. From a 1.3 liter engine a power output of 238HP is achieved without use of turbo or compressor. That is 183hp per liter which is impressive. Best atmospheric cylinder engines in the world like those in BMW and Honda achieve only around 100Hp/liter of displacement.
So the advantages are obvious, what about disadvantages? Well Wankel engine uses more fuel per displacement (although it produces more power) . Also design of seals is complicated and still much can be done in that perspective. There are several other problems but they are mostly connected with relatively low amount of research money spent on these engines today. There is also a lack of awareness of the existence of such an engine design.
Engine design has so much room for new inventions that this is a brilliant opportunity for those of you with innovative ideas to contribute. More efficient engines designs would help radically bringing down the cost of transportation, ultimately saving our planet in the process.
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27 Comments
i would like to use the biogas in the wankel engine because the biogas is a hydrocarbon and can be used in the combustion of engines which is environmentally friendly
can you guys there help me give some information that how make a mini model rotary engine assembly_diagram..because im doin a project for rotary..im searchin but cant find it...please can you guy help me here..
i want to use wankel engine plese tell how to improw efficience?
venkat
Can you please contact me ??
it's the smallest engine for cars we ever think of it .
If there is anyone out there with an efficient, modern rotary or eccentric rotary engine, please let me know
hi there! being a mechanical engg. i've great interest in automobiles. the wankel engine was of my great interest right from the begining of my graduation.. if you have any advancement research information regarding wankel engine please let me know.
Dear Umesh
here is my email ., please contact me ,
I would love to talk and point to you the better engines,
eagerly waiting your email
best regards
to answer patrick tunga question .
I am not an engineer this is what I know please ask an expert and the net for true details but i will give it a try.
In a normal engine during the compression stroke, as the charge of air and fuel is being compressed by the pistons movement up to wards top dead center, 5 to 15 degrees BEFORE piston reaches TDC the spark plug ignites the mixture , WHY ?
This action of pree ignition in intended to allow for a complete flame deflagration or complete combustion of gases,
Hence complete pressure build up before Piston is at TDC, this timing effort is intended to make best use of the gasses pressure, see you want to have the maximum and complete gas pressure al ready built up meet the piston at TDC or Just after TDC, so that gas pressure is at maximum and burning of gasses is already complete , other wise if you ignite the charge AT TDC then you will have flame deflagration following the piston down hill trying to catch up to it and pressure is in the process of building up or being generated as the piston is going down , in other words pressure is trying to catch up to the downward speeding piston , instead of acting on the piston with pressure.
I hope that is clear .
it takes a bit of imagination to imagine that but it is true you can test it on old cars with classical ignition systems.
Timing of the ignition depends of many thing , fuel type , load, air , RPM , engine design etc
That is why computer engine are more efficient and powerful you can perfectly time the ignition.
In the Wankel one of there two processes can take place but not the other
The same charge compression does take place in a Wankel, but not the pree ignition
In the Wankel the pree ignition is imposable to implement for lots of reasons, starting from the fact that the area of the rotor is large enough that the pressure of the pree ignited gases would prevent the rotor from completing its turn.
Also the combustion chamber of the Wankel is very small ,and is momentarily created it doesn’t last that long .
this creates more problems one of which is the fact that the flam deflagration is so slow to spread across all of the gas fuel mixture (charge) so they use two spark plugs to ensure as wide spread flam deflagration as possible.
So you cannot have gases pressure build up as the rotor is moving to TDC . you can only hope for best ignition exactly at TDC and since the rotor passes to fast at TDC the need to create as many as possible of ignition points to deflagrate the flam as much as possible.
If I know correctly Wankel don’t do good n low RPMs they have to Rev up to get any power .
By the way Wankel is rubbish, it is not even a rotary engine it is an eccentric rotary engine.
See my blog or email me if you want to know the true rotary engines that have the true power of rotary engine and none of the Wankel disadvantages .
Pree ignition is possible in my engine design,complete torque, no wobbly mass, very high compression ratio , all ready supercharged, higher volumetric efficiency , high power to weight ration etc .
I hope this answers your question.
sorry for the long post
hey i would wish to know why the wankel engine uses the twin spark plug.
please advice, thanks in advance
I'll bet this is a trick question... or at least a leading one ;^)
The reason Wankel engines are not wide spread is also the reason there are 2 plugs in most (ie, Toyo Kogyo, that is Mazda) designs. The combustion chamber formed by the rotors against the rotor housing is a terrible shape, long and thin, which means:
1. The flame front has to burn a long thin charge. More complete burning is possible if it's ignited in 2 places
2. The "chamber" has a large surface area, and moves as the rotor moves. Lots of heat is lost, very inefficient
3. A relatively large part of the charge doesn't burn. The unburned hydrocarbons in the exhaust pollute or have to be burned in what is essentially an afterburner... more air is pumped in, and the heat is wasted.
Lots of engineering has gone into trying to solve these problems using a stratified charge, where the mixture is in the correct air/fuel ratio in the middle of the "chamber" and becomes as close as possible to just air at the tips of the rotor and the sides of the "chamber". The supposedly coming soon Mazda 16X engine tries to address this by injecting fuel directly into the "chamber" area and by resizing all the dimensions of the housings and rotors to achieve the smallest practical surface area for the volume. They had not changed the dimensions since the '60's, except for the thickness of the rotors.
But at the end of the day, these problems seem intractable... you can't get the efficiency out of it. And then there is the problem that it needs to have huge area sliding surfaces lubricated, so you have to inject (and therefore burn) oil, which most people are not used to. And there is only one company working on it, and their design is essentially exactly the same as it was in 1968...
And... I've driven one for almost 20 years. They feel absolutely amazing, smooth (just rotating motion) and the faster it spins, the more power it makes. Takes less than a day to pull out of the car, disassemble, overhaul and reinstall, it's just a hand full of parts.
pls. can you give me an advice
? because my rx7 wankel engine does'nt work already.. my problem is i already change a 2 new egnition coil. but; why is it that theres is no fire will go out.. because i already change my two ignition coil but those black box under the first ignition that i will never change.. and i wonder why that, why is it that it will never start the engine.. but those electronic black box only that i never change because there's no available 4sale here in our town.. thanks!!
i want to know more design and structure to produce wankel engine. So please tell me about wankelengine working design and components.
dear i want to know that waht is tha purpose of internal gear, wich is shown in red colour, in wankel engin
i need tha meaning and references of gass turbine
well it's really not up to the corporations... it's all up to us. if everyone that complains about fuel efficiency went out and bought a car that was fuel efficient then the auto makers would listen... because their sells in other cars would drop... and Mazda does have the new RX-8 out... been out for a few years. It's a great car and gets pretty good gas mileage. (and doesn't sound like a sewing machine anymore)
You are obviously spamming but I'll leave it as it's good information.
Dear all thank you for having my words here on your blog.
Thank you for you comments.
But I think you got the wrong idea.
I am not promoting the Wankel engine.
The Wankel engine is an Ec-centric Engine, with only 20 to 30% thermal efficiency.
What I am promoting is Concentric Circular engines, that achieve 60-70-90% even 95% thermal efficiency.
Mr.Vladimir Prelovac Thank you for having my words on your blog. I want to add you to my web log but I didn’t know where.
Please all visit my web log for more details especially
http://dreamer3000.wordpress.com/circular-engine/
in my weg pages and blog roll you will fined
Hekal has the best literature.
Ciqular has animation and Pictures of the model.
VGT has animations of explanations science .
Jonova has nice photos and links to University of Arizona.
Issa Omran
Best regards
Dear All
Thank you for posting my words in your weblog.
The previous post I was talking about the difference between jet engine and circular engine.
Please make the distinction between Circular engines and the Wankel engine, the Wankel isn’t circular it is an Ec-centric circular engine.
please visit the real discussion about circular engines
http://dreamer3000.wordpress.com/circular-engine/
I wanted to link to your weblog bit didn’t know where to put yours.
Please Visit the main page
Best regards
http://dreamer3000.wordpress.com/circular-engine/
Wankel engien is fake Circular engine there is a fmily of engies
Called the circulare engines
here are the Advantiges details
a- The small size of the combustion chamber in Circular engines means higher pressure, while jet engines combustion chamber are huge.
b- Simplicity , un like the jet engine that requires really high end technology, high-Tech manufacturing and sophisticated designing aerodynamics calculations and engineers to manufacture / maintain. This circular engine requires basic machining abilities and basic understanding of rudimentary science not just to maintain but also to Home produce so manufacturing infrastructure is cheaper and smaller.
c- More / Tighter Sealed, meaning better utilization of gas pressure, that would explain the increase in thermal efficiency.
d- Thermal efficiency it is Calculated by a Professor Hekal to be any where from 60% to 90%. While any Jet engine is 50% thermal efficiency. Number don’t lie check Hekal website from my blog.
e- Which would mean less fuel consumption . also since it is a pulsating engine. burn small amounts of fuel sequentially not continually like Jet engine, so this Circular engine uses less fuel even at higher RPMs.
f- The increase in Thermal efficiency would also mean it would run cooler that makes sense if it has higher thermal efficiency it means it is making more use of the thermal / heat power so it is cooler running.
g- Which means even cheaper metals can be used. Unlike Jet engines that require really expensive metals and high end sophisticated metals casting / forming techniques. Or like the normal ICE that wastes a lot of heat putting limitations of the manufacturing of the parts of the engine like the head and valves and piston .So the already established metallurgy science wouldn’t find it hard to deal with a cooler running engine. It might use normal Alloys if not Aluminum. Which also means Cheaper to produce.
h- Looking at previous point Can be manufactured any where even HOME MADE if you will, DIY. So its Easier to manufacture.
i- Smaller in size even than a Jet engine .check the MYT engine comparison Picture. Smaller cars vehicles
j- Lighter. I estimate 50 to 60 KGs I believe 20KGs is possible for an engine that is more powerful than a V8.
k- Produces less sounds than a Jet engine. I think that is a BIG BIG advantage.
l- Higher Compression Ration 30 to 1. I don’t think even Jet engine produce such high compression ratio, this means this engine would be more powerful than any engine all ready manufactured. And it means especially that hydrogen is a wonderful fuel for this engine bringing the hydrogen economy to existence also for smaller WFC system. Since the energy density of Hydrogen is not good enough with these Circualr engines it would make sense.
m- Easy to maintain.
I think producing this Circular engine in your own work shop is a lot more attainable than a home made Jet engine don’t you think??
The Hekal has the Bet scientific literature
The Cirqular has nice clear Pictures of the prototype model and a movie clip very important people on the board of the company.
The VGT is not so friendly but has nice animations along with scientific explanations of the pros of the engines, but there specific design is not so good.
The SS-BF engine page has nice Films of actual model(s), but these engines waste energy but there stop and start motion. At least three different models from three different countries.
The page Circular engine has my attempt to explain the key differences.
The right side shows my summary of original websites while the lower right side of the pages show the original website links
The normal Reciprocating piston engine has negative torque which consists of work against air fuel mixture in next charge preparing cylinder/ Piston + work against the Springs cams frictional forces + the increase of the Gases started burning Before TDC of the next piston.
By making combustion chamber in circular engines separate from the Induction /compression chamber you don’t get the negative torque of the pre detonation of the Charger before TDC. Which means that wastes negative torque is moved to the positive side in circular engines meaning you win it back.
Also meaning no knocking.
There is no advancing of spark in Jet engines since they are continuous burn engines.
The Wankel doesn’t have any advancing of the spark, losing huge amounts of power since the gasses are actually following the rotor. And is only efficient at high RPMs.
Diesel
If you didn’t know I tell you that Diesel has more power (enthalpy) than Gas
But Diesel engines have huge amount of negative torque and no advancing of detonation, while in any of these circular engines Diesel would have NO or very small negative torque and would have advancing or detonation, so the diesel would end up more powerful than Gas engine
I hope this answers all questions relating to the advantages
I will not evade the fact that there is no one single working design. there are huge problems with sealing . and combustion chamber forming.
The problem is in designing one that really works. That is where the race is.
Beset regards
http://dreamer3000.wordpress.com/circular-engine/
I remember seeing a video (about 13 years ago!), about a compressed-air engine.
It was amazing, as it used a small 2-stroke engine to pump air into a "compressed air" tank.
The compressed air was then used to drive the main engine cylinders.
Apparently, it was incredibly fuel efficient... and could also generate a lot of power (for short amounts of time).
I vaguely remember figures like 5 liters per 100Km, and 0 - 100Kph in 7 seconds... really impressive.
What happened?
Apparently a big car maker bought the technology, and then shelved it.
what i dont like is i have a 1990 ford festiva and its pushing 40 to 50 miles to a gallon in 1990 and we have cars that have fuel cells that get that good. so i ask if they did it then, then whats the problem now. and may i add that it is a 1.3 liter 4 cylinder with a 4 speed manual thanks
Reminds me of the mid 70's when me and my mate use to cruise around in his father's RX-7 (In New Zealand). Trouble was, the "sewing machine" noise it generated. Maybe in time the wankel (or rotary) will resurface in another application, it deserves to...
It is a genius design in a sense that the only other design is a very bad one.
But I am sure much more clever design than Wankel engine still can be made. I am somehow still not bought on the idea of triangular body rotation as a best possible solution. I do not know why, maybe I am not a triangles guy.
Anyways, investing in Wankel design is surely a step forward for humanity, but corporations are the ones that will decide.
That's the whole problem, is existing infrastructure does not allow for the massive retooling that would need to take place, companies would have to spend millions to invest in this new technology.
Aside from that, the only real benefit of this engine is performance, and less maintenance. Automakers would rather not lose valuable profits on maintenance and repair, and not everyone wants to sacrifice performance for fuel economy.
It's a shame we start out with the wankel, it's a genius design and if as much innovation was put into this motor as we have in the otto style, we would be much more progressed. The seals and oil leaking issues could be solved with enough research.
Good article though, I really enjoyed it!
Hehe cheers to that :)
Wankel engines have big advantages but so much money has been already spent in building cylinder engines that it is still not economically justifiable for big corporations to turn to them.
When I hear stuff like this how things can be so much more efficient and cost effective for everyone but no one is doing enough about it, it pisses me off!
Now all I want is that bloody Mazda cause they're bold enough to lead. Damn it, when will the Japanese auto makers all get in on this and blow the American standard into hiding. Hehe. My two cents.
Great post!!!!!! Brilliantly enlightening.