FIELD OF INVENTION
This invention relates to a six stroke internal combustion (IC) engine. Particularly this
invention relates to a six stroke IC engine based on either spark ignition engine or
auto ignition engine running on all types of fuels, for example, petrol, diesel or
gasoline.
BACKGROUND OF INVENTION
Internal combustion (IC) engines are as such known in the art These engines use
either a two/four-strokes thermodynamic cycle. The main parts of such an engine
are a cylinder containing a piston effecting a reciprocal movement which is
converted into a rotating movement by means of a connecting rod and of a
crankshaft. The four strokes of a spark ignition engine will now be briefly explained.
The piston sucks up an air-fuel mixture by going back in first stroke and then
compresses it by going front in second stroke and the fuel evaporates under the
increase of temperature. When the piston comes close to its front dead point, a
spark plug ignites the mixture by means of a spark which provokes a sudden rise of
temperature and of pressure. During third stroke piston moves backward and
permits combustion gases to expand and the usable work is produced at this
moment. Finally, in fourth stroke that is the forward movement of the piston, the
gases produced in the cylinder after combustion. Therefore, the four strokes are the
admission, the compression, the expansion and the discharge. The diesel engine
uses a comparable principle where the difference resides m the way "'^ introriucing
the fuel, which, in this case, is directly injected into the compressed air. and
therefore hot air, and flames up then spontaneously combustion of fuel takes place.
In both the cases, the energy or efficiency depends, among others, on the
compression volume ratio. The higher it is, the higher is the efficiency. Unfortunately,
this compression ratio is limited, in the case of the gasoline engine, by the nsk of
premature knocking of the mixture and in the case of the diesel engine among
others by the necessity to keep an appropriate combustion chamber Anyway, it is to
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be noted that for a thermodynamic cycle as disclosed above, the increase in
efficiency becomes weaker and weaker for an equal increase of the compression
ratio starting from a value of 10 to 15 for the latter, and, in the case of the diesei
engine, the mechanical stresses determine mainly the critical volumetric
compression ratio.
A six stroke engine has been disclosed in the US patent no. 4917054, which
comprising six strokes for the admission of air. The first compression accompanied
or followed by a possible cooling. A second compression followed by combustion
The first expansion producing a usable work and the second expansion producing a
usable work and finally the discharge of the combustion gases. In this engine the
combustion is either with spark-ignition or with auto ignition and will include
preferably a multiple of five non-uniform cylinders and will have an energy efficiency
of up to 30 % higher than that of four stroke IC engine.
A dual six stroke IC engine is disclosed in the US patent no. 7143725 B1. The
engine comprises a turbo and a cooling cylinder to compress cooi air onto the
engine head to reduce engine temperature. The invention generally reduces the size
and manufacture cost of the cooling equipments such as radiator and intercooler by
cooling the power cylinder from within. Additionally this invention slightly increases
fuel efficiency and reduces exhaust temperature.
There are disadvantages associated with the prior art. One of the disadvantage of
the prior art is that there is some burnt fuel gases left in the cylinder even after fourth
exhaust stroke, this burnt fuel gases mixes in the first intake stroke, which does not
allow full amount of fuel to be taken during the first intake stroke, resulting into drop
in efficiency of the known engines.
Another disadvantage of the prior art is that for particular amount of power
developed, more heat is generated as it not dissipated fully in the atmosphere and
thus causes heating of the engine i.e. cylinder body
Yet another disadvantage of the prior art is that the life of the engine is reduced
because of excessive generation of heart.
Still another disadvantage of the prior art is that the efficiency of the known engines
is low because of left over gases in the cylinder even after fourth discharge stroke.
A further disadvantage of the prior art is that mileage of the known engine is low
because of leftover burnt gases in the cylinder as it mixes with the fresh fuel intake.
OBJECS OF THE INVENTION
Therefore, an object of the present invention is to provide a six stroKe IC engine
which obviates the disadvantages associated with the prior art.
Another object of the present invention is to provide a six stroke IC engine having
more energy and mileage, that is, the mileage of the engine has been increased with
the increase of the engine strokes.
Yet another object of the present invention is to provide a six stroke IC engine
wherein burnt fuel is completely exhausted during fourth and sixth stroke
Still another object of the present invention is to provide a six stroke IC engine
wherein burnt fuel gases are discharged completely and thus allow intake of the
fresh gases.
Another object of the invention is to provide a six stroke engine which discharges
completely the burnt gases from the cylinder which allows to enter full amount of fuel
during the first intake stroke to enhance the efficiency of the engine by reducing the
temperature of the cylinder body and enhancing to convert more full amount of
mechanical work from the fuel in the engine.
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still another object of the presentation invention is to provide a six stroke engine
which reduces discharge (amount to no residual) of the partly burnt through the
exhaust port which creates pollution in the atmosphere.
Another object of the presentation invention is to which provide a six stroke engine
where full energy in the burnt fuel is tapped during the power stroke, resulting in no
wastage of energy in the exhaust stroke.
Yet another object of the presentation invention is to which proviae 3 six stroke
engine where for particular amount of power developed less heat is developed
which is dissipated in the atmosphere causes less heating of the engine i.e cylinder
body.
Still another object of the presentation invention is to 'which provide a six stroke
engine where efficiency of the engine is very high.
Further object of the presentation invention is to provide a six stroke engine which is
cheap in cost simple in construction.
Further object of the presentation invention is to provide a six stroke engine when
used in driving vehicle, the mileage obtained from the fuel is enhanced by 30% .
Still another object of the presentation invention is to provide a six stroke engine
where modification can be performed on the existing engine
STATE MENT OF THE INVENTION
According to this invention there is provided a six stroke tC engine comprising a
piston adapted to be disposed in a cylinder such that to be moved up and down
upon burning of fuel in the cylinder, cams of a special shapes being provided to
operate an inlet valve and an outlet valve such that to provide six strokes in one
combustion wherein during fourth stroke outlet vale is opened fuiiy for ull time and
during fifth stroke the outlet valve remains open partially for some time such that to
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get back a little amount of exhaust gases which facilitate fifth stroke and exhaustion
of the residual burnt gases completely from the cylinder during sixth stroke keeping
outlet valve opened completely during sixth stroke
BRIEF DESCRIPTION OF THE DRAWINGS
The six stroke IC engine according to a preferred embodiment is herein Jesci ,bed
and illustrated in the accompanying drawings wherein;
Figure 1 - shows the sectional view of the piston and cylinder assembly showing
inlet valve's operation,
Figure 2 - shows the sectional view of the piston and cy'inder assenbiy showing
outlet valve's operation,
Figures 3A &B - shows the set of gears used in six stroke engine
Figures 4A to C - shows the shape of cams used in six stroke engine
DESCRIPTION OF THE INVENTION
A device to locate objects is herein described with numerous f>pecific di nails sc as to
provide a complete understanding of the invention. However these specific details
are exemplary details and should not be treated as the limitation to the scope of the
invention. The invention may be performed with slight modifications
Referring to the drawings specifically figures 1 and 2. a piston 1 is accommodated
into cylinder 2 such that to be moved up and down upon oinnino of r^ie fuel HI the
cylinder 2. The piston 1 is connected to the crank shaft (not showi) through a
connecting rod (not shown) such that provide rotational movement to the crank
shaft. When the piston 1 moves down the inlet valve 3 is operiec to 3\k^:/ op: • ':q a ;
inlet port 4 due to the movement of a rocker arm 5. The rockkr arm 5 '-. ooe^.iit d bv
a special shaped cam 6 and thus admitting intake of the air tne! iniytur^:- :n ra^e of q
petrol engine or only air in case of diesel engine. During the second stroke pision 1
moves from down position to the up position in the cylinder and inlet valve 3 and
outlet valve 7 remains closed. During this stroke the air fuel is compressed
constituting a compression stroke. In case of petrol engine the compressed air fuel
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mixture is ignited with the help of a spark plug (not shown) at the end ot the second /
compression stroke. And in case of a diesel engine, diesei fuel in atomized form is
injected at the end of the second / compression stroke and ignited due to high
temperature and pressure automatically to facilitate combustion of fuel mixture. Due
to the combustion of fuel mixture inside the cylinder 2 a high pressure of the gases is
generated which pushes the piston from up position to the down position constituting
a third stroke. This stroke is a power stroke and provides power to run the engine
during all six strokes. Both valves 3 and 7 during the power stroke generally remain
c'osed. During the fourth stroke the piston moves from down position to up position
and the out let valve is opened to facilitate discharge of the exhaust gases through
the exhaust port 8. The outlet valve is opened with the help of a rocker arm 9 and a
special shaped cam 10 (see figures 2 and 4). Now the fifth stroke takes place and
during this stroke the piston moves from up position to the down position. At the end
of the fourth stroke and beginning of the fifth stroke the outlet valve 7 is opened
partially to facilitate movement of the piston during fifth stroke. Subsequently, valve 7
is opened fully to discharge exhaust gases through the exhaust port 8 and dunng the
sixth stroke. The piston 1 moves from down position to the up position so as to
discharge the residual burnt gases completely from the cylinder 2 Thus the exhaust
gases are taken out from the cylinder two time once during the founb stroke and
finally during the last / sixth stroke. This complete discharge of the burni gases gives
more room for the fresh fuel to be admitted during the first stroke and due to
absence of the residual gases in the cylinder. Also due to the extra revolution piston
inside the cylinder it provided more time to cool the engine and thus heating of the
engine has been reduced and therefore efficiency of the engine has been increased
The life of the engine has thus increased due temperature drop in the cylinder body
In one embodiment and if the six stroke engine of the present invention is used to
run a vehicle the mileage of the vehicle is increased in the range of 20 to 40 %.,.
i-^ Referring to figure^S, ihe gears 11 having plurality of teeth have bee-i shown. The
gear used with the crank shaft has more teeth then the gear used v/itn the crank
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shaft so as to provide three revolutions to the crank shaft during one power stroke,
that one revolution of the crank shaft. Number of teeth provided s for six stroke
engine, the cam shaft rotates once in three revolution of crank shaft, accordingly the
gears used for cam shaft and crank shaft is modified. The ratio of the teeth provided
on the respective gear mounted on the crank shaft and the cam shaft is three is to
one respectively.
' Reference is now made to figure^4, wherein special shaped cams used in the sixstroke
engine are shown. The special shapes have been provided to the cams to
operate the opening and closing of the inlet and out let valve properly such that to
exhaust the burnt gases completely and at the proper time and thus tc obtain
optimum efficiency of the engine. The extensions and curves are provided on the
periphery of the cams to synchronize opening and closing of the fuel inlet and fuel
outlet valves at the proper time in order to provided sufficiently amount of fuel to the
engine and exhaust burnt gases from the piston - cylinder assembly compieteiy and
thus increase efficiency and life of the engine and also to reduce pollution generated
by the IC engines.
In one embodiment the special shaped cam is provided in such a manner that the
inlet valve is opened for a longer time such to supply a httle more uiel so as to
generate more gases after combustion so as to facilitate *'^Th and sixtn strokes to
remove the burnt gases from the cylinder completely during the sixth stroke.
The cam provided to operate inlet valve comprises an extension such that to open
the inlet valve to allow fuel intake during first stroke of the engine only by opening
the inlet valve and keep it closed during all the subsequent stiokes
The cam provided to operate outlet valve comprises an extension having a curve on
one side such that to open the outlet valve fully duhng fourth stroke and partially in
the beginning of the fifth stroke and fully during sixth stroke and keep it closed during
all the other strokes.
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According to an embodiment of the present invention the timing of combustion of the
fuel is set in such a manner that the fuel is burnt once in three revolutions of crank
shaft.
According to an embodiment of the present invention a plurality of the six stroke
engines are arranged in such a manner that sufficient amount of power is generated
to complete the task by the engines, for example, heavy vehicles movement.
Certain features of the invention have been described with reference to the example
embodiments. However, the description is not intended to be construed in a limiting
sense. Various modifications of the example embodiments as well as other
embodiments of the invention, which are apparent to the persons skilled in the art to
which the invention pertains, are deemed to lie within the spirit and scope of the
invention.