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The Wankel engine is a type of internal combustion engine, invented by Felix Wankel, which uses a rotary piston instead of reciprocating pistons.
In the Wankel engine, the four strokes of a typical Otto cycle engine are arranged sequentially around an oval, unlike the reciprocating motion of a piston engine. In the basic single rotor Wankel engine, a single oval (technically a trochoid shaped) housing surrounds a three-sided rotor (a Reuleaux triangle) which turns and moves within the housing. The sides of the rotor seal against the sides of the housing, and the corners of the rotor seal against the inner periphery of the housing, dividing it into three combustion chambers.
As the rotor turns, its motion and shape and the shape of the housing cause each side of the rotor to get closer and farther from the wall of the housing, compressing and expanding the combustion chamber similarly to the "strokes" in a reciprocating engine . However, whereas a normal four stroke cycle engine produces one combustion stroke per cylinder for every two revolutions, i.e. one half power stroke per revolution per cylinder, each combustion chamber of each rotor in the Wankel generates one combustion 'stroke' per revolution, i.e. three power strokes per rotor revolution. Since the Wankel output shaft is geared to spin at three times the rotor speed, this becomes one combustion 'stroke' per output shaft revolution per rotor, twice as many as the four-stroke piston engine, and similar to the output of a two stroke cycle engine. Thus, power output of a Wankel engine is generally higher than that of a four-stroke engine of similar engine displacement in a similar state of tune, and higher than an engine of similar physical dimensions. In international sports car racing the FIA considers a Wankel engine to be equivalent to a four-stroke engine of twice the displacement; other racing series seem to have settled on 1.8 times the displacement.
Wankel engines have several major advantages over reciprocating piston designs besides the higher output for similar displacement and physical size. They are considerably simpler and contain far fewer moving parts. For instance, because valving is accomplished by simple ports cut into the walls of the rotor housing, they have no valveA poppet valve is the type of valve system used in most piston engines, used to seal the intake and exhaust ports. The valve is usually a flat disk of metal with a long rod known as the valve stem out one end. The stem is used to push down on the valve ans or valve trains; in addition, since the rotor is geared directly to the output shaft, there is no need for connecting rodIn a reciprocal piston engine, the connecting rod connects the piston to the crankshaft. It can rotate at both ends so that its angle can change as the piston moves up and down and the crankshaft rotates. The top end, with a small opening for the piston ps, a conventional crankshaftThe crankshaft is that part of an engine which translates linear piston motion into rotation. Generally more than one piston is attached to the crank to provide a smoother delivery of power to the rotating part, though many small engines, such as those fo, or balance weights, etc. The elimination of these parts not only makes a Wankel engine much lighter, typically half that of a conventional engine with equivalent power, it eliminates the reciprocating mass of a piston engine with its higher strain due to repetitious accelerationIn physics, acceleration (symbol: a is defined as the rate of change (or time derivative) of velocity. It is thus a vector quantity with dimension length/ timeČ. In SI units, this is metre/secondČ. To accelerate an object is to change its velocity over a and deceleration as well as its inherent vibration, producing not only a smoother flow of power, but the ability to run at higher rpmRotational speed (sometimes called speed of revolution indicates for example how fast the motor is running. Rotational speed is like angular speed but not same: rotational speed tells how many rotation events there are per time unit and angular speed tell, thereby producing more power.
In addition, this simplicity and small size allows for a savings in construction costs.
As another advantage, the shape of the Wankel combustion chamber and the turbulence induced by the moving rotor prevent localized hot spots from forming, thereby allowing the use of fuelFuel is material with potential energy which can be transferred into kinetic energy, or as heat or mechanical work. In most cases this is just something that will burn. There are many different types of fuel. Solid fuels include coal, wood and peat. All t of very low octane number without preignition or knock. This is a particular advantage for Hydrogen cars.
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