Why can’t they think of some light weight engine and small volume engine ?? I am fed up of carrying this weight in the air I might go down one day .

What shall we do?? Shall we take weight penalty or shall we take high cost ??

Felix Wankel finally found a solution to the problem and developed an engine we today know as WANKEL ENGINE.

Thank you Felipe you made my life easy and happy !!

Wankel basically focussed his research that time on 3 things :

•Few parts.

•No ‘sudden death’

•Smoothness and combustion

FEW PARTS

•Number of parts are less especially moving parts.•Generally two parts are in motion- rotor and eccentric shaft•If there are 2 rotors moving parts are now 3 which is still smaller than 40 moving parts in piston engine•Rotor(S) moving at a speed 1/3 as that of eccentric shaft.

No ‘SUDDEN DEATH’

•Rotor is made of cast iron and rotor housing material of aluminium

•Immune to sudden shut down and produce power during its failure stage.

•Complete contrast to piston engine which is likely just “break”

SMOOTHNESS AND GOOD COMBUSTION

•Methodical rotation of rotor on eccentric shaft is smooth as compared to constant and sharp direction changes of moving parts in piston engine.

•Combustion duration is almost ¾ of the stroke time.

2-CYCLE OR 4-CYCLE ??

People ask if wankel engine is a 2-cycle or a 4-cycle engine.Well, It’s neither. It’s a WANKEL!!

FEATURES OF WANKEL ENGINE

•No reciprocating parts.•No vibrations.•Simple construction and compactness.•No separate intake exhaust valve mechanisms.

ENGINE PARTS AND GEOMETRY

Parts:

Rotor Rotor Seals Rotor Housing Cooling Jacket Output Shaft Stationary Gear Intake and Exhaust ports

Rotor: The heart of a rotary engine is the rotor. This is roughly the equivalent of the pistons in a piston engine. The rotor is mounted on a large circular lobe on the output shaft. This lobe is offset from the centerline of the shaft and acts like the 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.

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..

Rotor Seals

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.

Lubrication of rotor housing, phasing gear and the shaft.

Lubrication of apex seals, side seals and bore.

Lubrication system in wankel

Fuel sump

Oil pump

filter

Oil cooler

Main oil line

Main bearing

Ecentric bearings

rotor

Side plates

Layout of lubrication system of typical wankel engine

In addition to normal internal lubrication, the rotary engine uses oil injection. A pump injects a measured amount into the intake manifold. Oil from these nozzles goes to the engine and lubricates the rotor seals.

cooling

a) Air coolingb) Water coolingo Axial flow type cooling systemo Circumferential flow cooling system

c) Rotor cooling

Air cooling

Water cooling

Rotor cooling

It works on four phase cycle principle

As the rotor moves through the housing, the three chambers created by the rotor change size sinusodially. This size change produces a pumping action

the offset lobe on the output shaft spinning three times for every complete revolution of the rotor.

How wankel Engines Work

Wankel engine design

Rotating circle with radius RR

fixed circle with radius Rf

RR/Rf =3/2e = RR-Rf=Rf/2RR/e=3/1

Eccentric circle of radius e

Outer part is having two lobed epitrochoid shape and rotor is of equilateral shape

Major axis = R+eMinor axis =R-e

R

FOUR STROKES OF WANKEL ENGINE

POWEREXHAUST

Swept volume is maximum clearance volume minus minimum clearance volume Compression ratio is (Vmax+Vcc)/(Vmin+Vcc)

Swept volume and compression ratio

IGNITION SYSTEM

•Electronic Ignition System.

•Cold Spark Plug.

•2 spark plug approach like in MAZDA ENGINE.

Use fuel of low octane rating.(due to inherent antiknock properties)

Mainly no Use of diesel. Use of hydrogen as a fuel is possible.(Mazda

succeeded in commercializing the world's first hydrogen rotary engine when it started leasing the RX-8 Hydrogen in February 2006 )

Fuel and it’s characterstics

EXHAUST EMISSIONS CHARACTERISTICS

•Unburnt hydrocarbons: These are in large concentration in wankel engine as compared to reciprocating engine

•Carbon monoxide: for all values of air/fuel >14.8 co emission is almost zero

•Oxides of nitrogen: These are low as compared to reciprocating engine

•Combustion chamber shape:

EXHAUST EMISSION CONTROL SYSTEM

•Thermal Reactor System 1. Continuous emission is advantageous.

2. Installed on the bottom and also in direct contact of the engine.

3. Design ensures that to keep the exhaust gases in reactor as long as possible

CxHy +zO2 xCO2 + yH20

•Catalyst system ( used by Japan and U.S.A.)

Catalyst used mainly is palladium ,platinum and rhodium

FUTURE DEVELOPMENT OF ROTARY ENGINES

•Fuel injection type rotary engine: controlling the time and amount of Fuel supply more accurately as compared to carburetter( Audi-NSU,West germany developing this engine)

`

Stratified charge type Complete combustion

of fuel Reduction hc and co

levels

Super charger type Allow engine to

develop sufficient supercharge effect at low and medium speed (time induction with supercharge)

Compression charge recirculation wankel engine

Multi rotor type Improvement in

performance by increasing total displacement

Easier balance with inertia forces and couple

Two stage diesel rotary engine

Developed by rolls royce(Great Britain)

ADVANTAGES Funk (Siek) FK-12

Comet (with Wankel engine)

small size and lightweight

construction.

Much simpler comparing to its

piston counterpart.

relatively low in NOx emissions

Power to weight ratio is superior than

piston engines.

Smooth power flow and high RPM.

smaller frontal area than a piston engine

of equivalent power, allowing a more

aerodynamic nose to be designed around

it.

fewer moving parts than piston engines of equivalent power output.  

No sudden seizure 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 fuel of very low octane number or very low ignition power requirement without preignition or detonation, a particular advantage for hydrogen-burning cars.

DISADVANTAGES

imperfect sealing against the chamber ends, which counts for leakage between adjacent chambers, and unburned fuel mixture.

High Operating Temperature, the housing operates at steady state with constant heating in each chamber.

Low fuel efficiency and shorter engine life due to damaged seals.

The engine’s operation also allows for more unburned hydrocarbons in the exhaust

small amounts of oil end up in the working chamber leading to high maintenance costs

They typically consume more fuel than a piston engine because the thermodynamic efficiency of the engine is reduced by the long combustion chamber shape and low compression ratio.

APPLICATIONS

Mazda rx8

Automobile racing Aircraft engines Range extender In 2010 Audi revealed that in their electric car,

the A1 e-tron, they would have a small 250 cc Wankel engine running at 5,000 rpm that would recharge the car's batteries as needed.

In 2010 FEV Inc revealed that in their electric version of the Fiat 500 a wankel engine would be used as range extender as well.

Other uses go-karts, personal water craft and 

auxiliary power units for aircraft.

•High performance motor cycle.

•Snowmobile.

•Outboard engine.

•Helicopter engine.

•General purpose engine.

•Industrial engine.

•Chain Saw engine.

•Passenger Cars.

Challenges & Difficulties

Transmission• Many moving parts• Gear ratios were very difficult to get right• Constraints started conflicting

Engine• Measurements for rotor pieces and rotor housing were difficult to obtain• Some pieces needed to be generated by equations• Interference between housing and rotor was an issue• Inserting gear constraints between all moving parts was difficult to get right

FUTURE OF WANKEL ENGINE

1. Because of the arising environmental regulations and in the consequence of the oil crisis of 1973 no more investments were done.

2. Only Mazda continued to develop at the rotary engine (e.g. in 1999 they produced a new car with a wankel engine inside).

3. 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.

4. In this engine, fuel consumption is now within normal limits while passing California State emissions requirements, including California's Low Emissions Vehicle (LEV) standards.

THANK YOU FOR LISTENING

It was huge but we tried to make it worth .

BY:1. Abhimanyu Bhatia2. Ashok Seervi3. Ashutosh Agarwal4. Karuturi R. Chowdhary