Mazdas rotary engine, eh?
can someone explain the difference between a 'normal' engine and a rotary one.
my dad tried to explain it a few year ago. iwas as clueless then as now.
Answers:
Imagine a coke can sliding up and down a tube. This is a normal piston. A small hole at the top of the tube opens and a petrol/air mix squirts in. A spark makes it explode and the piston whizzes down the tube. Another hole opens at the top and as the piston goes back up all the burnt stuff is pushed out the tube, ready for the next cycle. If you have four of these "tubes" in a row, you have a four cylinder engine. You can probably imagine how wasteful and wearing it is for the pistons to be exploded downwards, then almost immediately braked to a halt and flung back upwards again, maybe 100 times a second.
Now a Rotary is more like a revolving door, with 3 compartments. The petrol air mix is pushed in through the entrance as each compartment passes; then as it swings into the building an explosion propels it round. Once the compartment reaches the other opening, all the burnt air escapes. We all know how easily you can spin a revolving door just by giving it a little push every time it comes round. There is no wasted energy stopping and starting it like a piston. And of course, each of the compartments is doing something at any time - loading, exploding or emptying. Obviously, the shape of the cylinder and rotor are specially designed.
The biggest drawback is that the seal - that bit of brush strip along the edge of a revolving door - has to be airtight, fireproof, friction free and able to whizz round at high speed for years without wearing out. Also, the fuel consumption is unavoidably poor.
Apologies to all the engineers out there for my wild generalisations.
Hope that gets you started!
It means they go quite fast and cost a lot of money should things go wrong.
you REALLY need pictures to understand it.
It's generically a 'Wankel' engine, plenty of tech stuff on line
In rotary engines each rotor section basically has a triangular shaped rotor that acts as three cylinders. Usually you will find a one or two rotor engine. They are very complicated to work on and very expensive to build and maintain. They do however make great power for their size.
Try this link for more info;
http://en.wikipedia.org/wiki/mazda_wanke.
ordinary car engines have pistons which move up & down in cylinders compressing air and fuel vapour which is burned, this spins a crankshaft / gearbox drive / and ultimately the wheels. rotary engines don't have pistons, a roughly triangular rotor spins in a shaped combustion chamber the rotor tips are in contact with the walls of the combustion chamber as it spins it compresses the fuel, fires it , and takes in a fresh fuel/air charge, the crankshaft/gearbox/ final drive is the same on both.
I owned an '86 RX-7 Sport quite a number of years ago and it was a great little car. My one gripe was that it used about a quart of oil every 2,000 miles.
A 'normal engine' has pistons that slide up and down in a set cylinder. I hope you understand the basics of how a 'normal' 4 stroke engine works (Intake, Compression, Combustion, Exhaust).
Like a piston engine, the rotary engine uses the pressure created when a combination of air and fuel is burned. In a piston engine, that pressure is contained in the cylinders and forces pistons to move back and forth. The connecting rods and crankshaft convert the reciprocating motion of the pistons into rotational motion that can be used to power a car.
In a rotary engine, the pressure of combustion is contained in a chamber formed by part of the housing and sealed in by one face of the triangular rotor, which is what the engine uses instead of pistons. The rotor follows a path that looks like something you'd create with a Spirograph. This path keeps each of the three peaks of the rotor in contact with the housing, creating three separate volumes of gas. As the rotor moves around the chamber, each of the three volumes of gas alternately expands and contracts. It is this expansion and contraction that draws air and fuel into the engine, compresses it and makes useful power as the gases expand, and then expels the exhaust.
If you need more let me know and I'll try to explain it in finer detail.
A rotary engine is an internal combustion engine, like the engine in your car, but it works in a completely different way than the conventional piston engine.
In a piston engine, the same volume of space (the cylinder) alternately does four different jobs -- intake, compression, combustion and exhaust. A rotary engine does these same four jobs, but each one happens in its own part of the housing. It's kind of like having a dedicated cylinder for each of the four jobs, with the piston moving continually from one to the next.
The rotary engine (originally conceived and developed by Dr. Felix Wankel) is sometimes called a Wankel engine, or Wankel rotary engine.
Improve on Perfection?
How would you improve the rotary engine in order to make it a more vialble alternative to the traditional piston engine?
Share your thoughts.
In this article, we'll learn how a rotary engine works. Let's start with the basic principles at work.
Like a piston engine, the rotary engine uses the pressure created when a combination of air and fuel is burned. In a piston engine, that pressure is contained in the cylinders and forces pistons to move back and forth. The connecting rods and crankshaft convert the reciprocating motion of the pistons into rotational motion that can be used to power a car.
In a rotary engine, the pressure of combustion is contained in a chamber formed by part of the housing and sealed in by one face of the triangular rotor, which is what the engine uses instead of pistons.
The rotor and housing of a rotary engine from a Mazda RX-7: These parts replace the pistons, cylinders, valves, connecting rods and camshafts found in piston engines.
The rotor follows a path that looks like something you'd create with a Spirograph. This path keeps each of the three peaks of the rotor in contact with the housing, creating three separate volumes of gas. As the rotor moves around the chamber, each of the three volumes of gas alternately expands and contracts. It is this expansion and contraction that draws air and fuel into the engine, compresses it and makes useful power as the gases expand, and then expels the exhaust.
We'll be taking a look inside a rotary engine to check out the parts, but first let's take a look at a new model car with an all-new rotary engine.
Mazda RX-8
Mazda has been a pioneer in developing production cars that use rotary engines. The RX-7, which went on sale in 1978, was probably the most successful rotary-engine-powered car. But it was preceded by a series of rotary-engine cars, trucks and even buses, starting with the 1967 Cosmo Sport. The last year the RX-7 was sold in the United States was 1995, but the rotary engine is set to make a comeback in the near future.
The Mazda RX-8 , a new car from Mazda, has a new, award winning rotary engine called the RENESIS. Named International Engine of the Year 2003, this naturally aspirated two-rotor engine will produce about 250 horsepower. For more information, visit Mazda's RX-8 Web site.
The Parts
A rotary engine has an ignition system and a fuel-delivery system that are similar to the ones on piston engines. If you've never seen the inside of a rotary engine, be prepared for a surprise, because you won't recognize much.
Rotor
The rotor has three convex faces, each of which acts like a piston. Each face of the rotor has a pocket in it, which increases the displacement of the engine, allowing more space for air/fuel mixture.
At the apex of each face is a metal blade that forms a seal to the outside of the combustion chamber. There are also metal rings on each side of the rotor that seal to the sides of the combustion chamber.
The rotor has a set of internal gear teeth cut into the center of one side. These teeth mate with a gear that is fixed to the housing. This gear mating determines the path and direction the rotor takes through the housing.
Housing
The housing is roughly oval in shape (it's actually an epitrochoid -- check out this Java demonstration of how the shape is derived). The shape of the combustion chamber is designed so that the three tips of the rotor will always stay in contact with the wall of the chamber, forming three sealed volumes of gas.
Each part of the housing is dedicated to one part of the combustion process. The four sections are:
Intake
Compression
Combustion
Exhaust
The intake and exhaust ports are located in the housing. There are no valves in these ports. The exhaust port connects directly to the exhaust, and the intake port connects directly to the throttle.
Output Shaft
The output shaft has round lobes mounted eccentrically, meaning that they are offset from the centerline of the shaft. Each rotor fits over one of these lobes. The lobe acts sort of like the crankshaft in a piston engine. As the rotor follows its path around the housing, it pushes on the lobes. Since the lobes are mounted eccentric to the output shaft, the force that the rotor applies to the lobes creates torque in the shaft, causing it to spin.
The output shaft
(Note the eccentric lobes.)
Now let's take a look at how these parts are assembled
if you want picts go to www.rotaryengineillustrated.co.
the rotary engine is special, it is something different then everybody else. If you own an RX7 third generation life will be good. the power is great. Rotary engine do not break down that easy because they dont have a lot of moving part. If it run well the first day it will run untill you forgot to put in the oil. Check this site out on how it work.
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