THE WANKEL ENGINE

WHAT IS WANKEL ENGINE?

 

    The Wankel engine is an internal combustion rotary engine that uses the rotary motion of a triangular shape rotor mounted in an elliptical-shaped chamber to transform the thermal energy into rotary motion. The Wankel engine is also known as a rotary because the rotor is the most important main part of the engine that moves in a spinning motion.

MAIN PARTS OF THE WANKEL ENGINE 

HOW WANKEL ENGINE WORKS

The Wankel engine is a four strokes engine that works 4 cycles:

1. Intake
2. Compression
3. Combustion /  ignition
4. Exhaust

1.    INTAKE

    The intake process starts when the tip of the rotor passes the intake port. At the moment when the intake port is exposed to the chamber, the volume of that chamber is close to its minimum. As the rotor moves past the intake port, the volume of the chamber expands, sucking air-fuel mixture into the chamber. When the tip of the rotor passes the intake port, the chamber is sealed off and compression begins.

2.    COMPRESSION

    As the rotor continues its spinning motion around the housing, the volume of the chamber gets smaller and the air-fuel mixture gets compressed. By the time the surface of the rotor is facing to the spark plug, the volume of the chamber is again close to its minimum.

3.    COMBUSTION

    Wankel engine have two spark plugs. The combustion chamber is long, so the flame would spread too slowly if there were only one plug. When the spark plugs ignite the air-fuel mixture, then the pressure quickly builds up forcing the rotor to move.

4.    EXHAUST

    As the rotor continues to move, the chamber starts to contract, forcing the exhaust gases out of the exhaust port. By the time the volume of the chamber is nearing its minimum, the tip of the rotor passes the intake port and the whole cycle starts again.

WANKEL ENGINE WOKING MOTION

ADVANTAGES AND DISADVANTAGES

ADVANTAGES

1. Wankel engine is a simple design.
2. A Wankel engine has no valve for operation.
3. Crankshafts and connecting rods are not required in this type of internal combustion engine. The removal of these components makes the engine lighter.
4. Has a wide range of speeds.
5. Capable to burn high-octane number fuel without knocking occurs.

DISADVANTAGES

1. High Sealing Loss, Wankel engine housing has slightly different temperatures in each separate chamber segment. The various substance expansion coefficients contribute to imperfect screening. 
2. Lifting of the Apex seal, centrifugal force forces the apex seal on the engine surface of the bodies to create a firm seal. In the light-load activity, gaps between the apex seal and housing may develop in the event of centrifugal force and gas pressure imbalances.
3. High rate of emissions, because unburned fuel is in the exhaust flux as fuel is used, emissions standards are difficult to fulfill. Direct fuel injection into the engine combustion chamber will solve this problem.
4. Low fuel economy of petrol fuel, this happened due to the moving combustion chamber, which contributes to poor combustion and good pressure at part load and low rpm. This leads to unburned fuel joining the exhaust flux.
5. Wankel engine has a low compression ratio. Due to this reason, they have low fuel economy and thermal efficiency.