EFFECT OF DIRECT WATER INJECTION IN PERFOMANCE OF A SIX STOKE ENGINE

SUBMITTED BYSREERAM K AEFFECT OF DIRECT WATER INJECTION IN PERFOMANCE OF A SIX STROKE ENGINEGUIDED BYMr. RAJU M DAsst professor ,FISAT

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CONTENTSINTRODUCTIONSIX STROKE ENGINEWORKING OF A SIX STROKE ENGINETHERMODYNAMICS OF SIX STROKE ENGINEEXPERIMENTAL ANALYSISCOMPARISON BETWEEN SIX STROKE AND FOUR STROKE ENGINESCONCLUSIONDRAWBACKS OF A SIX STROKE ENGINEFUTURE SCOPE AND BETTERMENTREFERENCES11/14/20152

INTRODUCTION4-stroke engines are the most widely used type of IC engine4-stroke engines are highly reliable and durableIn a 4-stroke engine large amount of energy is taken away by exhaust gases.4-stroke engine creates high pollutionThermal efficiency is very low.Energy loss through cylinder wallsLarger cooling losses

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SIX STROKE ENGINEThe concept of six stroke engine was developed in mid 20th centuryThe six stroke engine using water was developed by Brush Crower in 2006.Six stroke engine is a type of internal combustion engineAdditional two strokes make it more efficient and reduce the emission.The engine captures heat, which is lost from conventional four stroke cyclePower is produced by introducing water inside the super heated cylinder.

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WORKINGIn a six-stroke engine, the combustion chamber temperature reaches approx. 800 C

Just before the fifth stroke, fresh water is injected directly into the hotcombustion chamber through the engine's water injector pump.

Water quickly turned to superheatedsteam

Water to expand to 1600 times its volume and forces the piston down for an additional Power stroke11/14/20155

The working principles of six stroke engine is based on the concept of four stroke engine but with some modification, another two strokes are added.

SUCTION STROKEThe piston moves from top dead center to the Bottom dead center and creates vacuum pressure . So the Air and fuel mixture is sucked in to the Cylinder.

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COMPRESSION STROKE The piston moves fromBottom dead center to top deadcenter and compresses the Mixture. The mixture is compressedTo high temperature and pressure.

POWER STROKE: At the end of compressionstroke the fuel is ignited andburnt. The pressure inside the cylinder increases rapidly and it pusses the piston down and the power is transmitted from piston to wheel.

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EXHAUST STROKE:The Burnt product is pushed through the exhaust valve by the upward movement of the piston.

SECONDARY POWER STROKE:At the end of the exhaust stroke the cylinder temperature becomes around 700-9800 C. At this stage water is injected by an Injector in the form of fine droplets.

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The water turns into vapour increasing volume around 1600 times when it comes in contact with the superheatedcylinder.

SECONDARY EXHAUST STROKE:In this stroke the water vapour is exhausted by the upward motion of the piston.

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Working

FIG: WORKING OF 6 STROKE ENGINE11/14/201510

Cylinder pressure for the six stroke engine

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Work obtained by six stroke is the sum of the both combustion work and vaporization work. So that the break mean effective pressure will increase.

Ideal six stroke cyclePressure and volume diagram11/14/201512

Thermodynamic analysis of power strokes:Fuel power stroke:

Water injection 20 power stroke

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EXPERIMENTAL ANALYSIS11/14/201514A single cylinder, four stroke, spark ignition Honda GX 270 model test engine was used in the experimentsNew cam profiles were determined and designedA electronic control unit was utilized in order to control the water injector.The test engine was coupled with Cussons P8160 model DC dynamometer which was rated 10 kW at 4000 rpm engine speed.Engine speed was measured by pick-up sensor mounted on the dynamometer shaft.The experiments were conducted at full load condition between 2250 and 3500 rpm engine speed.

BRAKE TORQUE AT DIFFERENT RPMs

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INFERENCES FROM THE GRAPH:

It is possible to say that brake torque generally decreases with the increase of water injectionThe most effective water injection was seen between 2750 and 3250 rpm The water injection quantity was limited in order to increase engine performance at lowest and highest engine speeds.Unstable operation occured when the engine run at 2250 and 3500 rpm engine speeds with water injection. The reason of the decrease of brake torque after a certain water injection is due to decrease in cylinder temperature.

PERFOMANCE AND WATER INJECTION

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INFERENCES FROM THE GRAPH:

It can be clearly stated that the engine operated stable during water injection in between 2500 and 3250 rpm engine speed. With water injection brake power increases upto 3000 rpm and then decreases.Fuel consumption increased with the water injection due to increase of volumetric efficiency.Specific fuel consumption decreased upto 2750 rpm with the water injection and then increased.There is no significant difference between fuel consumptions with and without water injections. Specific fuel consumption decreased with the water injection as exhaust heat energy was converted to useful work

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EFFECT OF WATER INJECTION ON THERMAL EFFICIENCY

EXHAUST AND WATER INJECTION

Thermal efficiency increased with water injection Maximum thermal efficiency was obtained with water injection at 2750 rpm.Thermal efficiency increased by about 8.72%Overall engine performance improved with water injection.CO emission is lower with water injection at lower and medium rpms.CO emission decreases 21.97% until 3000 rpm.The increase of CO emission at higher rpm is due to lack of sufficient oxygen delivery because of flow losses

COMPARISON BETWEEN FOUR STOKE AND SIX STROKE ENGINES

FUEL FLOW RATE:The amount of fuel flow to the engine per unit time is known as fuel flow rate.

As the diagram shows the fuel flow rate of 6-stroke engine is 50% lesser thanthe conventional 4-stroke engine.

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THERMAL EFFICIENCY

The thermal efficiency of the engine is the power produced by the engine to the power available from fuel.

The thermal efficiency of the four stroke engine lies between 20-30%, where asThe thermal efficiency of six stroke engine lies between 40-50%.

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CONCLUSION11/14/201520Exhaust gas temperature and engine wall temperatures decreased 7% and 2%Brake power increased 10% with water injection. In contrast , specific fuel consumption decreased 9%.There is no remarkable effect of the water injection quantity and injection advance on engine performance at lowest (2250 rpm) and highest(3500 rpm) engine speeds.Thermal efficiency and engine performance improve with the proper water injection quantity.CO and HC emissions decreased 21.97% and 18.23% until 3000 rpm respectively.

CONCLUSION CONTD...Uses rejected heat from engineFuel economy increases to 60% of conventional enginePower output per stroke is moreExhaust gas emission is lowHigh thermal Efficiency There is 40% reduction infuel consumption.Extracts work from heat that is ordinarily lost through the cooling system of a conventional engine.Reduces exhaust emissions per a given power range.Steam stroke cools the engine internally hence the use of much highercompression ratios.The weight and power loss of conventional cooling system parts can be eliminated.

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LIMITATIONS AND DRAWBACKSInjecting relatively cold water onto a hot metal piston can damage it over time from thermal expansion and contraction.Separate water tank would have significant weight and space penaltiesA steam-free cool down reduces the temperature inside the combustion chamber.Cold climate anti-freezing measures would be needed in the water reservoir.Early engine starting problem.Running problem in cold region.Requirement of neutral water.

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BETTERMENT AND FUTURE SCOPETo prevent damages due to the action of cold water, we can utilize the exhaust gases for pre- heating of water.We can use a condenser instead of a separate water tank which will reuse the distilled water for a period of cycles.To compensate the temperature drop inside the chamber we can further increase the Compression ratio which increases the power output making it suitable for higher power requirements. 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.

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REFERENCE11/14/201524[1] Arabac E. Conversion of a four-stroke spark ignition engine to six stroke engine with exhaust heat recovery and investigating of the engine performance and exhaust emission characteristics. PhD. Thesis, GaziUniversity GSNAS, Ankara; 2014. p. 123.[2] Arabac E. Six-stroke reciprocating engine. The Journal of Graduate School of Natural and Applied Sciences of Mehmet Akif Ersoy University, 3(2): 2012; 3745. ISSN Online: 13092243.[3] _Icingur Y, Arabac E. The idealized air-fuel cycle and the performance analyses of a six-stroke spark ignited engine. Gazi Universitesi J Polytechnic 2013;16(1):3744.[4] Saidur R, Muzammil W, Hassan M, Paria S. Technologies to recover exhaust heat from internal combustion engines. Renew Sustain Energy Rev 2012;16:564959.[5] Conklin J, Szybist J. A highly efficient six-stroke internal combustion engine cycle with water injection for in-cylinder exhaust heat recovery. Energy, Knoxville 2010:165864.[6] Pulkrabek W. Engineering fundamentals of the internal combustion engine. New Jersey: Prentice Hall; 2003. p. 103108..

11/14/2015257] Prater DM. Multiple stroke engine having fuel and vapor charges. United States patent 6,253,745; 2001.[8] Crower B. Method and apparatus for operating an internal combustion engine. United States patent application 20070022977; 2005.[9] engel YA, Boles MA. Thermodynamics: an engineering approach. 5th ed. Boston: McGraw-Hill; 2005.[10] Delft University of Technology, Energy Technology Section. FluidProp: software for the calculation of thermophysical properties of fluids. The Netherlands. See also, http://www.FluidProp.com; 2004.[11] Heywood JB. Internal combustion engine fundamentals. New York: McGraw-Hill; 1998.