What is Wankel Rotary Engine? Operation and construction.

Wankel Rotary Engine- 

Engines are generally regularly utilized everywhere. They have turned into a significant piece, everything being equal. A Wankel motor is a kind of IC rotational motor that utilizes the revolving movement of a three-sided rotor mounted in a curved chamber to change the nuclear power into turning movement without utilizing the conventional responding cylinder. The Wankel motor is otherwise called a revolving motor since it has all the turning parts.

The German architect Felix Wankel created the rotational motor known as the Wankel turning engine and it for the most part utilized in race vehicles. The Wankel motor chips away at the conventional Otto cycle yet vary from the responding I.C. motors. By 1957, Wankel had constructed an exploratory revolving engine that was running on a proving ground, and in 1964 this motor was proposed to people in general in the NSU Wankel Spyder. This little, back-engined sports vehicle had a 498cc Wankel motor, yet it could create 50bhp and had a maximum velocity of 95mph (152km each hour).


The figure shows a simplified diagram of the Wankel Rotary Engine. It consists of a three-lobe rotor (a rotor of tri-angular shape with curved sides), that rotates eccentrically in an oval chamber. The rotor is mounted on the crankshaft through external and internal gears. The rotor lobes A. B and C are sealed tightly against the sides of the oval chamber. The combustion of rotor and chamber shapes ensures that they remain in contact with each other throughout the rotation. The rotor has an oval-shaped depression on its three sides between the lobes, as shown by dashed lines.

As the rotor turns, the revolution and the state of the lodging push the rotor nearer to the lodging wall and the motor burning chamber nearer and farther down the “strokes” of an equal cylinder. Be that as it may, these 4 phase motors produce an ignition stroke after two upsets of the cylinder inside the chamber.


The three-lobe rotor makes three spaces around it in the oval chamber. The four cycles of intake. compression, power, and exhaust go on simultaneously in the three spaces around the rotor when the engine is running.

Intake stroke- 

This image represents
the fuel intake, in which the rotor side AB
creates suction. The fuel mixture from the carburetor enters the suction chamber. As the
rotor turns clockwise, the mixture is compressed between
the rotor and the chamber, as at. 

Compression stroke-

As the rotor begins pivoting, the hole between corner A to corner B of the principal chamber (as displayed in the above chart) decreases because of that the volume of the combination diminishes, and the pressure of the blend happens.
As the air-fuel blend is compacted by the necessities, it is sent for the ignition cycle.

Power stroke- 

As the combination of the primary chamber (between A to B corners) is compacted by the necessity, a flash fitting presents a flash inside the chamber, which lights the air-fuel blend.
Because of the start, the blend is changed over into high temperature and tension gases. The energy of the combusted combination powers the rotor to push ahead. This interaction goes on until the first corner passes by the exhaust port.

Exhaust stroke- 

At the point when corner A contacts the fumes or release port, the high-pressure copying gases are released from the motor.
In the wake of releasing exhaust gases, the exhaust port closes.

Thus, the cycle is complete. The same cycle of operations goes on on all three sides of the rotor simultaneously. It is obvious that there are three power impulses in every revolution of the rotor, which is three times compared to a two-stroke engine and six times compared to a four-stroke engine. The engine delivers power almost continuously. The eccentric motion of the rotor develops vibrations which are eliminated by the use of two symmetrically mounted flywheels.

Advantages of Wankel Engine- 

1. Wankel rotary engine is smaller in size, lighter in weight, and more compact as compared to reciprocating engines.

2. It is cheaper and simpler in construction for mass production due to the absence of many working parts like connecting rods, crankshafts, valve mechanisms, etc.

3. Its balancing is easier because it does not contain any reciprocating parts. Road tests have proved that this engine is practically free of vibrations.

4. Its volumetric efficiency is very high, often exceeding 100%.

5. Its power output per kg of the engine is considerably higher. 

6. Its running cost is less. 

7. It does not require overdrive because its speed is very high. 

Disadvantages of Wankel Engine-

1. Higher fuel consumption at low-speed ranges.

2. Higher oil consumption per B.P.

3. Lower torque speeds.

4. Braking effect of the engine is far less.

5. Reduction of speed in the transmission is necessary due to very high engine speed.

6. Due to the ignition troubles experienced with ordinary ignition systems, the spark plug has to be changed frequently. However, this has been remedied by using transistorized ignition.

7. The main obstacle in the development of the Wankel rotary engine was the sealing problem, which has been largely overcome by now.

8. Cylinder distortion may occur due to the close proximity of the inlet and exhaust ports.

9. Very high exhaust gas temperatures, nearly 1,600°F creates problem in the exhaust manifold and silencer designs.

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