SIX STROKE ENGINE

SUBMITTED BY-ROLL NO- 1305440061

CONTENTS:-Introduction………………..Objective……………….Classification of six stroke engine……………….Comparison of six stroke engine with four stroke

engine………P-V and Torque –angle diagram……………….Advantages………………….Limitations…………………Conclusion……………….References.

Introduction:- One of the most difficult challenge in engine

technology today is the urgent need to increase engine thermal efficiency.Higher efficiency means less fuel consumption & lower atmospheric emissions per unit of work produced by the engine.

The six stroke engine is a type of internal combustion engine based on the four stroke engine,but with additional complexity intended to make it more efficient and reduce emissions.Additional complexity means adding two more stroke in the four stroke CI or SI engine.

Objectives:- There are the following objectives: (i) Reduction in fuel consumption.(ii) Reduction in pollution.(iii) More extraction of work per cycle. (iv) Higher thermal efficiency of cycle.

Classification:The six stroke engines catagorised in two catagories according to design

of the piston of the engine.(a)First Approach(Single piston design):-In the first approach the engine

captures the heat lost from the four stroke Otto cycle or diesel cycle and uses it to additional power and exhaust stroke of the piston in the same cylinder.In this type either steam or air used as the working fluid for the additional power stroke.Ex:

(i)Crower six stroke engine.(ii)Dyer six stroke engine.(iii)Bajulaz six stroke engine.(iv)Velozeta six stroke engine.(b)Second Approach(Double piston design):-It uses a second opposed piston

in each cylinder that moves at half the cyclical rate of the main piston,thus giving six piston movements per cycle.Ex:

(i)Beare head six stroke engine.(ii)M 4+2 six stroke engine.

Crower’s six stroke engine:In a six stroke engine developed in U.S. by Bruce

Crowner,distilled water is injected in to the cylinder after the fourth stroke, and is quickly turned to superheated steam,which causes the water to expand to 1600 times its volume and forces the piston down for an additional stroke.

Working:-(i)Suction stroke (1st Stroke):-During the first stroke the piston

move from TDC to BDC by which inlet valve open and air fuel mixture from carburetor sucked in to the cylinder in case of SI or fresh air in case of CI engine through the inlet manifold.

(ii)First compression stroke(2nd stroke):-During the second stroke piston moves from BDC to TDC by which fuel air mixture compressed in the cylinder both valves remain closed during this stroke, the compressed fuel air mixture inginited by the spark plug thus combustion occurs inside the cylinder.

(iii)Expansion stroke/First Power stroke(3rd stroke):-During this stroke product of combustion applied pressure on the piston by which piston moves from TDC to BDC both valves remains closed during this stroke.

(iv)Second Compression stroke(4th stroke):-The fourth stroke is again a compression stroke .The piston move from BDC to TDC where the remaining exhaust gases are compressed whichis similar to second stroke.

(v)Second Power stroke(5th stroke):-Just before the end of the compression stroke distilled water is sprayed in the combustion chamber with the help of water injector.Due to fine spray of water and high temperature it immediately gets converted in to superheated steam.The steam applied pressure on the piston and piston moves from TDC to BDC.Thus thermal enegy of steam is now converted in to mechanical energy.

(vi)Exhaust stroke (6th stroke):-During the six stroke exhaust valve open and inlet valve closed ,the piston move from BDC to TDC the waste gases and the steam are released.

Dyer’s six stroke engine:- It is similar to the Crowner’s six stroke engine.

Bajulaz six stroke engine:-It is similar to regular combustion engine in design.There are ,however modification to the cylinder

head with two supplementary fixed capacity chamber:-

(a)A combustion chamber.(b)Air preheating chamber.

Working:-(i)First stroke:-Intake of pure air in cylinder (5),valve(1)is open.

(ii)Second stroke:-compression of pure air in the heating chamber (7),valve (2) is open.

(iii)Third stroke:-Power stroke (work)-release the combustion gases in the cylinder valve(3)

is open.

(iv)Fourth stroke:-Exhaust the combustion gases valve (4) is

open.

(v)Fifth stroke:-Power stroke(work)-release of pure gas in the cylinder.

(vi)Sixth stroke:-Recompression of pure air in to the combustion chamber.

Velozeta six stroke engine:- In a Velozeta engine, four strokes are similar to the four stroke

IC or SI engine. Fresh air is injected in to the cylinder during the exhaust

stroke,which expand by heat and therefore forces the piston down for an additional power stroke .

The engine seems to show 40% reduction in fuel consumption. The engine can run on a variety of fuels,ranging from gasoline

and diesel fuel to LPG. It shows 65% reduction in CO pollution when compared with

the four stroke from which it was developed.

Beare Head six stroke engine:-This design was developed by Malcom Beare of

Australia.The technology combines a four stroke engine

bottom end with an apposed piston in the cylinder head working at half the cyclical rate of the bottom piston.Fuctionally the second piston replaces the valve mechanism of a conventional engine.

The top and bottom crankshaft are connected via a drive chain or toothed belt.

M 4+2 six stroke engine:- The M4+2 engines have much in common with the Beare Head engines,

combining two opposed pistons in the same cylinder. One piston works at half the cyclical rate of the other, but while the main function of the second piston in a Beare Head engine is to replace the valve mechanism of a conventional four stroke engine, the M4+2 takes the principle one step further. The double-piston combustion engine's work is based on the cooperation of both modules. The air load change takes place in the two-stroke section of the engine. The piston of the four-stroke section is an air load exchange aiding system, working as a system of valves. The cylinder is filled with air or with an air-fuel mixture. The filling process takes place at overpressure by the slide inlet system. The exhaust gases are removed as in the classical two-stroke engine, by exhaust windows in the cylinder. The fuel is supplied into the cylinder by a fuel injection system. Ignition is realized by two spark plugs. The effective power output of the double-piston engine is transferred by two crankshafts. The characteristic feature of this engine is an opportunity of continuous change of cubic capacity and compression rate during engine work by changing the piston's location. The mechanical and thermodynamical models were meant for double-piston engines, which enable to draw up new theoretical thermodynamic cycle for internal combustion double pistons engine.

Comparison of six stroke engine with four stroke engine(P-V diagram for Otto cycle):-

P-V diagram for dual cycle:-

Torque-angle diagram for four stroke engine:-

Torque-angle diagram for six stroke engine:-

Advantages:- Due to an additional power stroke efficiency of the engine increased. Better scavenging and more extraction of work . Reduction in fuel consumption by at least 40%. No cooling system required like heat exchanger in case of Crower six

stroke engine. Reduction in pollutants like NOx, CO ,CO2,photochemical smog etc,

up to 55%. Multiple fuel used like as Bajulaz six stroke engine. Increase in indicated thermal efficiency. Minimize necessity of heat exchanger e.g. radiator.

Limitations:- Engine size increase due to number of cylinder and additional

components. Higher manufacturing cost of six stroke engine.

Conclusion:-The concept of Six Stroke Engine seems to be rather eco-

friendly and low fuel consuming which can fulfill the needs of near future.

A lot of experiments are being conducted in order to improve the efficiency and workability of the engine.

References:• Kiran P , “ A feasibility study on waste heat recovery in six stroke

I.C. Engine, International Journal on Mechanical Engineering and Robotics (IJMER), Volume-1, Issue-1, 2013.

• Vijay Chauhan, "A Review of Research in Mechanical Engineering on Recovery of Waste Heat in Internal Combustion", 2012

• James C. Conklin, James P. Szybist “ A highly efficient six stroke internal combustion engine cycle with water injection for in-cylinder exhaust heat recovry” Energy 35 (2010) 1658-1664 .

• IC. Engine by V Ganesan,TMH.• www.google.com• www.wikipedia.com• www.quasiturbine.com/QTMarchettiSthSixStroke0509• www.bajulazas.com• www.velozeta.com• www.sixstroke.com