six stroke engine ion

8/4/2019 Six Stroke Engine ion

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Technical Seminar topic onTechnical Seminar topic on

SIX STROKE ENGINESIX STROKE ENGINE

Presented By:-

BHOJARAJA.B.G

Dept of mechanical engg.GMIT


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CONTENTS

Introduction

How six stroke engine works

Working principles

Specification of six stroke engine

Comparison of six stroke engine with four strokeengine

Graphs

Gallery

Thermodynamic advantages Conclusion

References


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Introduction

Malcolm beare built an innovative hybrid design ofthe I C engine , by combining a two stroke with afour stroke engine.

The Beare Head is a new type of four stroke

engine head design known as the Beare Head

The Beare Head uses a piston and ports verymuch like a two stroke engine to replace the overhead valve system that is found in four strokeengines today. The four stroke block, pistons andcrankshaft remain unaltered. This combination oftwo stroke and four stroke technology has giventhe engine its name the six stroke engine (2 + 4= 6).


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Key attributes of the Beare Head

are:

Increased power,

Increased torque,

Fewer, lighter reciprocating parts,

Simpler manufacture.


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HOW SIX STROKE ENGINE

WORKS


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Below the cylinder head gasket, everything is

conventional, so one advantage is that the Beare

concept can be transplanted on to existing engineswithout any need for redesigning or retooling the

bottom end. But the cylinder head and its poppet

valves get thrown away. To replace the camshaft and

valves, Beare has retained the cam drive belt andfitted an ultra short-stroke upper crankshaft complete

with piston, which the belt drives at half engine speed

just as it previously drove the cam. This piston drives

up and down in a sleeve, past inlet exhaust ports setinto the cylinder wall, very much like on a two-

stroke: these are all exposed during both inlet and

exhaust strokes.


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Working Principle

Fuel ignites with

piston at the top

dead center.


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Rotary valve

opens, allowing

exhaust to

escape


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Exhaust

stroke begins

when the

piston is atbottom dead

center


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Exhaust stroke

ends, intake

begins. rotary

valve cutsexhaust .intake of

charge into

cylinder due to

pressuredifference.


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The intake strokehappens when thepiston is on itsdownward path withthe intake valveopen. This actioncreates suction,drawing atomized

fuel in this casegasoline mixed withair, into thecombustion

chamber.


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Top piston nearly

closes completeinlet port and The

compression

begins.


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Combustion

chambercompletely sealed

and ready for the

combustion.


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The power strokebegins at a criticalmoment, just as the air-fuel mixture is at its mostcompressed. Asupercharged voltage isdelivered to the sparkplugs from the ignitioncoil, at that point it ignitesthe fuel mixture. Thevalves in the engine arestill closed during thisperiod. Thus the

explosion forces thepiston down to turn theengine's crankshaft,delivering the power viathe gearbox and clutch to

the driving wheels.


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SPECIFICATION OF SIX STROKEENGINE

PROTOTYPE 5 - DUCATI BASED


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Comparison OfSix Stroke Engine

With Four Stroke Engine


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1. In a six stroke engine the energy absorption is less because

of slower acceleration of reciprocating parts.

2. It reduces the weight and complexity of the engines head by

as much as 50%. Instead of using energy to drive the head.

3.Torque is increased by 35% and efficiency increased by

the same.

4.Increased torque and power output.


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Gallery

UPPER CRANK WITH PISTON


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DISC VALVEThe piston is half way up on the exhaust stroke. When the piston

reaches TDC with the ports fully open, the disk will begin to

cut off the exhaust. The valve runs clockwise


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CYLINDER HEAD

FROM BELOW

CYLINDER

HEADUPPER VIEW


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Thermodynamic Advantages

The intake begins at 0 degrees on the X-axis.

The effect of the additional volume changes that

the upper piston has on the volume of the engine is

all positive from a thermodynamic point of view. If

the engine were a normal 4 stroke the cylindercapacity would be 340cc. Of note - maximum

volume at the end of the intake stroke occurs at

173 degrees instead of 180 degrees- the change in

volume is 308cc which is less than a 4 stroke(340cc)- yet the total volume at the end of the

intake stroke is 415cc as opposed to 375cc for a

conventional stroke.


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Thermodynamic advantages

The change in volume during the compression

stroke is slightly greater than a 4 stroke after the

ports are closed.

The expansion stroke is much greater than a 4stroke, both from T.D.C. to B.D.C. and from T.D.C.

till the exhaust port is open.

It is possible to leave the opening of the exhaustport later than in a 4 stroke because maximum

volume is not reached until after B.D.C.-548 deg.

Instead of 540 deg .


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Thermodynamic advantages

Hence the 6 stroke system is better from athermodynamic point of view because more energy

is extracted from the expansion process.

During the critical combustion period the rate of

change in volume in the 6 stroke is less than a 4

stroke. Minimum volume is not reached until after

T.D.C., at 361 deg. This is because of the phasing

of the upper piston. It is retarded in reaching its

T.D.C. until 20 deg. after T. D.C. (380). This is

much better from a thermodynamic view in thatcombustion occurs at a more constant volume;

hence ignition timing is not as critical as in a 4

stroke. There is room in the combustion chamber

for up to 4 spark plugs and two direct injectors if

needed.


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Conclusion

In a six stroke engine the energy absorption is lessbecause of slower acceleration of reciprocating

parts The piston speed of the upper piston is about

a quarter of the main piston; therefore its service

life should be at least twice that of the main piston.

In the Beare design, per single cylinder, thenumber of parts is 15 compared to a four stroke of

approx 40 to 50 parts. Also, to reduce

manufacturing costs the head and block can be

machined in o-ne piece.


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The bottom piston is a standard design and theBeare Head bolts directly o-nto the engine block,replacing the overhead valves and standard head.

It reduces the weight and complexity of the engineshead by as much as 50%. Instead of using energyto drive the head, the head actually developsenergy for conversion to power back through thetiming chains of an engine.

Torque is increased by 35% and efficiencyincreased by the same. This can be achieved bysimply unbolting an existing head of a four-strokeengine and then bolting on a Beare Head.


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Increased torque and power output,

Better fuel economy and cleaner burning longer

service intervals and considerably reduced toolingcosts when compared with a conventional four-

stroke design.


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REFFERENCES

1. www.autocarindia.com

2. www.sixstroke.com

3. www.dynobike.com

4. www.delphi.com

5. www.engineersedge.com

6. www.howstuffworks.com

7. Applied Thermodynamics by Rajput

8. Automobile Engineering by Dr. Kripal singh

9. Automobile engineering by G.Nagula

10. Mechanical Engineering science byK.R.Gopalakrishna


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THANK YOU

six stroke engine ion

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