6-STROKE ENGINE

PRESENTED BY:-AJIT KUMAR SAHOOREGD NO:-1421108002

INTRODUCTIONThe 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.

There are two power strokes: one with fuel, the other with steam or air.

Actual Prototype of SIX Stroke engine

COMPARISON OF 4-stroke and 6-stroke Engine

4-stroke One Power Stroke Up to 35% Efficiency More Emissions Minimal Power One Working Fluid

6-stroke Two Power Stroke Up to 45% Efficiency Comparatively Less

Emission More Power Two Working Fluid

WORKING OF 6-STROKE ENGINE

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 STROKE The 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.

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.

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 900-10000 C. At this stage water is injected by an Injector in the form of fine droplets. The water turns in to vapour increasing volume around 1600 times when it comes in contact with the superheated cylinder.

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.

Valve timing diagram of 6-stroke engine

IVO: Inlet Valve openEVO: Exhaust Valve OpenIVC: Inlet Valve CloseEVC: Exhaust Valve CloseWC : Water Injection

Cycle analysis and Comparison

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 than the conventional 4-stroke engine.

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 as The thermal efficiency of six stroke engine lies between 40-50%.

BRAKE SPECIFIC FUEL CONSUMPTIONIt is the ratio of fuel consumption per second to the brake

power.

As from the diagram the brake specific fuel consumption of 6-stroke engine is much lower than the conventional six stroke engine.

Factors affecting the engine performance

Water injecting pumpUsed fuel and lubricationValve timing of the engineTemperature of the cylinder wall

MODIFICATIONS REQUIREDFUEL TANK: The fuel tank should divided into two parts, as one part will contain fuel and the

other part will contain water. The water used should be neutral and distilled.

ENGINE COMPONENTS MATERIALThe engine components like piston, cylinder , cam, crank, valves etc. are subjected to severe thermal stress. The thermal stress developed due to the injection of water into the very hot cylinder. The rapid temperature changes may cause micro crack and fractures in the engine components as the periodical compression and expansion takes place.

So the engine components should be designed with high thermal resistive metal alloys to withstand the stress and prevent failure of engine.

The materials that can be used are… Silicon Nitride(Si3N4) Silicon Carbide(SiC) Zirconia(ZrO2) Alumina-Tungsten alloy etc.

CAM-SHAFT DESIGN

In four stroke original angular speed of camshaft is one half of the crankshaft. The crankshaft rotates once for every two revolution of the crank shaft.

4-stroke

The camshaft of 6-stroke engine contains three cams.Intake camExhaust camWater injector cam

6-stroke

Water Injection:The water injection is done by the help of water injector

which is operated by the cam. This thing can be done more effectively by the use of Water metering pump or by the progressive cavity pump.Water metering Pump:

A positive displacement pump capable of driving a fixed quantity of water into the cylinder at regular intervals, independent of the back pressure applied

ADVANTAGES There is 40% reduction in fuel 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 higher compression ratios.

The weight and power loss of conventional cooling system parts can be eliminated.

Limitations and Obstacles

Injecting 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 penalties

A steam-free cool down reduces the temperature inside the combustion chamber.

Cold climate anti-freezing measures would be needed in the water reservoir.