A SEMINAR PRESENTATION ON

SIX STROKE ENGINE

Presented by

Bhagawan Upreti

3NA11ME002

OBJECTIVE OF PRESENTATION

• To provide the concept of principle and working of six stroke engine.

• To show the advantages of six stroke engine over the conventional four stroke engine with the help of curves.

INTRODUCTION• A six stroke engine derived its name from the fact that it is a

mixture of two and four stroke engine

• The term six stroke engine describes two different approaches in

the internal combustion engine, developed since the early 1990s,

to improve its efficiency and reduce emissions. In the first

approach, the engine captures the waste heat from the four

stroke Otto cycle or Diesel cycle and uses it to get an additional

power and exhaust stroke of the piston in the same cylinder. The

second approach replaces the valve mechanism of a conventional

engine and also it increases the compression ratio.

HISTORY AND TYPES

• Its concept was developed in 1880s.However the rapid research commenced only after 1990s.

• During this,the developed engines are

• A. Single piston designs

• Griffin six-stroke engine

• Bajulaz six-stroke engine

• Velozeta six-stroke engine

• B. Opposed piston designs

• Beare Head

• M4+2

• Piston charger engine

•

WORKING PRINCIPLE

• It captures the waste heat from the four stroke Otto or dual

cycle and use it to power an additional power and exhaust

stroke of the piston.

• Designs either use steam or air as the working fluid for the

additional power stroke.

• The additional stroke cools the engine and giving 40%

increased efficiency over the four stroke engine.

WORKING

• 1st stroke (suction stroke):

Inlet valve opens, air fuel mixture enters the cylinder.

Piston moves from TDC to BDC.

• 2nd stroke (compression stroke) :

Piston moves from BDC to TDC.

Both the inlet valve and exhaust valve are closed and

The air-fuel mixture is compressed.

• 3rd stroke (1st power stroke) :

Power is obtained from the engine by igniting the

compressed air-fuel mixture.

Both valves remain closed.

Piston moves from TDC to BDC.

• 4th stroke (exhaust stroke) :

The exhaust valve opens to remove the burned gases.

Piston moves from BDC to TDC.

• 5th stroke (2nd power stroke):

Exhaust valve opens, air inlet valve opens.

Fresh air from the air inlet valve enters the cylinder through the secondary air induction system.

Piston moves from TDC to BDC.

Fresh water is injected directly into the hot combustion chamber through the engine's fuel injector pump.

Water is quickly turned to superheated steam.

Water expands to 1600 times its volume and forces the piston down for an additional Power stroke.

• 6th stroke (2nd exhaust stroke) :

The air exhaust valve remains open.

The steam exhaust is passed to the condenser through exhaust

valve.

Piston moves from BDC to TDC.

Hence six stroke cycle is completed.

ENGINE PARTS MODIFIED

Crankshaft to camshaft sprockets ratio.

• Crankshaft has 1080 degrees of rotation for 360 degree rotation of the camshaft per cycle.

• Hence their corresponding sprockets are having teeth in the ratio 3:1.

• In the four stroke engine the teeth of the sprockets of the camshaft and the Crankshaft was in 2:1 ratio.

• The 34 teeth sprocket of camshaft was replaced by a 42 teeth sprocket. The camshaft sprockets were also replaced from 17 teeth to 14 teeth to convert the four stroke engine into six stroke engine.

Cam lobes• The 360 degrees of the cam has been divided into 60

degrees among the six strokes.

• The valve provided at the exhaust has to be kept open during the fourth, fifth and the sixth stroke. The cam has been made double lobed in order to avoid the hitting of the exhaust valve with the piston head.

• The profiles of the exhaust and the inlet cams have been shown in the figure

Valve timing diagram• The inlet valve opening (IVO) is 0° at TDC, same as that of the

four stroke engine.

• Inlet valve closes (IVC) at 25° after BDC, same as that of the four stroke engine. Exhaust valve opens (EVO) 0° at BDC, which in the original engine was 25° before BDC.

• Reduction of 25° advanced opening of exhaust valve extract maximum work per cycle.

• Exhaust valve closes 10 degree before TDC in order to prevent the loss of air fuel mixture through the exhaust valve.

COMPARISON WITH FOUR STROKE ENGINE

ADVANTAGES• There is 40% reduction in fuel consumption.

• Higher overall efficiency and less emission of exhaust gas.

• Extracts work from heat that is ordinarily lost through the cooling system of a conventional engine.

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

• Torque increases about 23 and 9 % in otto and dual cycle.

PROBLEMS AND LIMITATIONS

• Injecting relatively cold water into a hot metal piston can damage it over time from thermal expansion and contraction.

• Separate water tank would have significant weight and space penalties.

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

FUTURE SCOPE

• Increased efficiency and low fuel requirement can lead to its extensive use.

• Further studies in new model development is being carried out.

• The automotive industry may soon be revolutionized by a new six-stroke design which adds a second power stroke, resulting in much more efficiency with less amount of pollution.

CONCLUSION• Six stroke engines are the technology for the future in vehicles.

• From the above given data it is clear that six stroke engines are better compared to two stroke and four stroke engines.

• The project is well patented and is undergoing heavy research works.

• Six stroke engines with all the desired qualities of a two stroke and four stroke engines will be hitting the market soon.

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