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Seminar On Wankel Engine Full PDF Report Download

Wankel Engine Seminar Report

ABSTRACT

A Wankel engine is an internal combustion engine, but it works in a completely different way than the conventional piston engine.

Like a piston engine, the rotary engine uses the pressure created when a combination of air and fuel is burnt. In a piston engine, that pressure is contained in the cylinders and forces pistons to move back and forth. The connecting rod and crankshaft convert the reciprocating motion of the pistons into rotational motion that can be used to produce power.
In a Wankel 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 Spiro graph. 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. 

WANKEL ENGINE PARTS:


Wankel Engine
Rotor:
The heart of a wankel engine is the rotor. This is roughly the equivalent of the pistons in a piston engine. The rotor is mounted on the large circular lobe on the output shaft. This lobe is offset from the centerline of the shaft and acts like crank handle on a winch, giving the rotor the leverage it needs to turn the output shaft. As the rotor orbits inside the housing, it pushes the lobe around in tight circles, turning three times for every one revolution of the rotor.

Rotor Housing:
The housing is epitrochoid in shape. Designed to keep all three tips of rotor in contact with housing at all times. Creates three separate volumes of gas at any time during rotation. Housing is designed with four parts specifically dedicated to one of the following: Intake, compression, combustion and exhaust.

Cooling jacket:
The hole (jacket) tracks which are provided to the border of the housing as show in fig., are used for the cooling purpose. During combustion very high temperature water cooling jacket is provided. For the housing cooling system it is important to minimize the temperature difference over the housing to prevent local thermal stresses and deformations as well as reducing its highest temperature. The axial flow type cooling is used in this engine

Stationary Gear:
For stationary gear, the profile shifted spur gearing is generally used. The stationary and rotor gears are designed for a gear ratio 2:3 and for their pitch diameter 4 and 6, respectively, so that the center distance will be equal to the eccentricity of the trochoid. The stationary gear is solid with the main shaft bearing housing,as show in fig. which is generally press fit and bolted to the side housing. The rotor gear is usually in the shape of a ring gear. 

Output Shaft:
Output shaft has lobes mounted offset from the centerline of the shaft. Rotors are mounted on these lobes. Each lobe acts as a crankshaft on the piston engine. When rotor follows the surface of the housing it creates torque on the lobes making the output shaft rotate.

WORKING PRINCIPLES


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.

Wankel Engine Animation
Image source: Wikipedia                                                                             Wankel Engine Animation 
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 Spiro graph. 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.

Advantages of Wankel Engine:
  1. Wankel engines are considerably simpler, lighter, and contain far fewer moving parts than piston engines of equivalent power output.
  2. The elimination of reciprocating mass and the elimination of the most highly stressed and failure prone parts of piston engines gives the Wankel engine high reliability, a smoother flow of power, and a high power-to-weight ratio.
  3. The Wankel engine is very quick to react to throttle changes and is able to quickly deliver a surge of power when the demand arises, especially at higher rpm.
  4. The Wankel engine for use in aircraft is the fact that a Wankel engine generally has a smaller frontal area than a piston engine of equivalent power, allowing a more aerodynamic nose to be designed around it.
  5. The simplicity of design and smaller size of the Wankel engine also allows for savings in construction costs, compared to piston engines of comparable power output. 
  6. Due to a 50% longer stroke duration compared to a four-cycle engine, there is more time to complete the combustion. This leads to greater suitability for direct injection.
  7. A Wankel rotary engine has stronger flows of air-fuel mixture and a longer operating cycle than a reciprocating engine, so it realizes concomitantly thorough mixing of hydrogen and air.

Disadvantages of Wankel Engine:
  • Wankel engines have major disadvantages when it comes gas mileage. They use more power comparative to piston engine.
  • They burn comparatively more oil than piston engines.
  • A typical wankel engine gets average mileage of about 25 miles per gallon.
  • Wankel engines tend to have more problems with seal than piston engines. Seal problem occurs more frequently, particularly in colder regions.
  • There is also an issue with the cost of some spare parts of wankel engines. Repair could be more expensive and maintenance cost is very high.
  • Fewer dealers are certified to fix Wankel engines, and regular dealerships of piston engines do not handle Wankel engines.
Applications Of Wankel Engine:
  • Motorcycle
  • Snowmobile
  • Outboard Engine
  • High-speed Boat
  • Light plane
  • Helicopter
  • Industrial Engines
  • Chain Saws
  • Model Engine
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