FORM-2
THE PATENTS ACT, 1970 (39 of 1970) & THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
VARIABLE SWIRL SYSTEM WITH SECTOR VALVE FOR SIAMESE TWIN INLET PORTS
KIRLOSKAR OIL ENGINES LTD.,
an Indian Company
of Laxmanrao Kirloskar Road, Khadki, Pune - 411 003
Maharashtra, India.
Inventor: VAZE ABHIJEET
The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF INVENTION
The present invention relates to the field of controlling the swirl ratio in an engine with Siamese twin inlet ports. Simply stated, the swirl ratio is a measure of the angular momentum of air inside the diesel engine cylinder. This air motion causes the mixing of air and a number of fuel sprays ejected perpendicular to the air motion path in order to facilitate a proper mixing of air and fuel to ensure combustion of the mixture by self ignition. The swirl is the ratio of the angular momentum to the engine speed and it controls the formation of mixture of diesel and air once diesel is sprayed inside the cylinder.
In particular, it relates to individual control of inlet ports by a valve in a diesel engine cylinder head in order to control in-cylinder swirl for better combustion
More particularly, it relates to a configuration of a sector valve to cover or uncover one of the ports to change the angular momentum of the air entering into the cylinder in order to change the position of a sector valve in a diesel engine. This angular momentum of air controls the mixing of air and fuel inside the diesel engine cylinder and is responsible for lower fuel consumption and emissions. These twin inlet ports normally share a common wall, as they are located side by side and therefore these are known as Siamese twin inlet ports. The first port located in the direction of the swirl is known as the upstream port and the second one is known as the downstream port.

BACKGROUND OF THE INVENTION
The diesel engine combustion depends on the proper mixing of air and fuel inside the cylinder. At various speeds, the proper mixing of air and fuel is dependent on the strength of the angular momentum of air perpendicular to fuel spray paths. It is known to the skilled person in the relevant field that the strength of the angular momentum depends on the speed of the engine.
It is also known to the skilled person in the field of diesel engines that proper mixing of air and fuel is essential for ensuring good combustion characteristics, which result in least emissions and greatest fuel economy. The diesel engine employs poppet valves in the cylinder head which open or close at a predetermined time and which are controlled by the cam-shaft cam profile in order to control the passage of air in the cylinder and to trap the mass of air so entrained in the cylinder. It is also known that the diesel is sprayed out radially through the injectors and air is made to rotate around the cylinder axis tangential to the path followed by diesel spray by suitably configuring the intake passage called as a port in the diesel engine cylinder head.
The uses of helix shaped ports known as helical port, straight ports known as tangential ports or directed ports, and combinations thereof, are known for controlling the angular momentum of air and thus controlling the mixture of air and fuel to obtain the desired combustion characteristics. It is also known to those skilled in the art that the helix shaped helical port is more resistant to the flow of air as it tries to swirl the air.

Thus, any increase in swirl is at the expense of the increased resistance to flow of air. The measure of this resistance to flow is known as the flow coefficient and is represented by a ratio of the actual mass of air to the theoretical mass of air entering into the cylinder through the port at a defined pressure drop and at a predetermined poppet valve lift across the port.
The use of sector valves placed in the intake ports or controlling the shape of the auxiliary passages connecting the helical port, is also known for controlling the swirl and the flow-coefficient. The sector valve results in a reduced flow-coefficient and thus, lowers the mass of air available for combustion.
OBJECTS OF THE INVENTION
Some of the objects of the present invention, which at least one embodiment herein satisfies, are as follows:
It is an object of the invention to facilitate proper mixing of air and fuel in an internal combustion engine.
It is another object of the invention to control swirl ratio in an internal combustion engine.
It is still further object of the invention to control inlet ports by means of a valve in an engine cylinder head.

It is yet another object of the invention to ensure good combustion characteristics, which result in least emissions and greatest fuel economy.
It is still another object of the invention to use a sector valve to simultaneously vary the swirl levels in a Siamese with least resistance to the flow of air through the ports.
Other objects and advantages of the present disclosure will be more apparent from the following description when read in conjunction with the accompanying figures, which are not intended to limit the scope of the present invention.
SUMMARY OF THE INVENTION
In accordance with this invention, there is provided a variable swirl system disposed in a cylinder head of an internal combustion engine, comprising Siamese twin inlet ports comprising a downstream port and an upstream port sharing a common wall and a sector valve which can be suitably positioned in order to simultaneously vary the swirl levels in said twin inlet ports by increasing or decreasing the momentum of the in-cylinder air for better mixing of air and fuel.
Typically, the sector valve comprises a prismatic cover welded to a shaft supported on bearing at both the ends thereof.
Typically, the sector valve is positioned to open or close one of said inlet ports for varying the in-cylinder swirl strengths during a small period of the valve lift by means of rotation of said prismatic cover about the axis of said shaft.

Typically, the sector valve opens or closes at least one of said inlet ports, either fully, or partially, at a very high frequency to control the mass of air entrained in the cylinder by means of the suction effect of air.
Typically, the variable sector valve can be used both for spark ignition or gasoline engines to.control the tumbling motion of the air inside the cylinder of said engine.
Typically, the position of said sector valve can be changed electronically by an actuator driven by means of an electronic control unit by sensing the manifold air pressure or the fuel pump rack position and the rpm of said engine.
Typically, the position of said variable sector valve can be changed either pneumatically or hydraulically by using engine oil from the lubricating circuit of said engine.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWING
The variable swirl system in accordance with the present invention will now be explained in more detail with reference to the non-limiting accompanying drawings in which:
Figure 1 illustrates a schematic representation of an exemplary embodiment of the variable swirl system in accordance with the present invention, which includes a sector valve assembled on the cylinder head of an engine and the general arrangement of the sector valve in its various positions;

Figure 2 illustrates the mounting of the sector valve on a shaft supported on bearings to reduce the friction;
Figure 3 illustrates an exemplary configuration of the sector valve shown in Figure 1, in a perspective view;
Figure 4 illustrates the closing of the upstream port when air travels via path 15; and
Figure 5 illustrate the closing of the downstream port when air travels via path 17.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWING
The variable swirl system in accordance with the present invention will now be described with reference to the embodiments-shown in the accompanying drawing. The embodiment does not limit the scope and ambit of the invention. The description relates purely to the exemplary preferred embodiment of the invention and suggested applications thereof.
The invention disclosed herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments thereof. The examples used here are intended merely to facilitate an understanding of ways in which these embodiments may be practiced and to further enable those of skill in the art to practice these embodiments. Accordingly, the examples should not be construed as limiting

the scope of the embodiments of the invention. The description hereinafter, of the specific embodiments of the variable swirl system will so fully reveal the general nature of its embodiments that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is merely for the purpose of description and not of limitation. Therefore, while these embodiments have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described in this specification.
The variable swirl system in accordance with the present invention will now be described with reference to the accompanying drawings which do not limit the scope and ambit of the disclosure. The description provided is purely by way of examples and illustrations.
The variable swirl system herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

The description herein after, of the specific embodiments of the variable swirl system will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.
Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
In accordance with the present invention and as illustrated in Figure 1, an exemplary embodiment of the variable swirl system is shown, including a sector valve 12 which can be positioned in various positions to obtain desired variations in the swirl inside the cylinder. The sector valve 12 is disposed in a moveable manner in a cylinder head 10 which in turn consists of Siamese twin inlet ports 2 and 7. The direction of swirl is clockwise as shown in the figure 1 by arrow 3. Therefore, the port 2 is known as the upstream port, while port 7 is known as the downstream port. The upstream port 2 and the downstream port 7 share a common wall in between and hence these are called as Siamese twin inlet ports and this sector valve 12 is used for ensuring variations in the cylinder swirl.

As illustrated in Figure 2, the assembly of the sector valve 12 consists of a shaft 3 and a cover 4. The shaft 3 is supported on suitable bearings at both ends 5, in order to reduce friction during the rotation thereof and to position the sector valve 12 in any desired position with ease. Thus, this shaft 3 and valve 4 together form an important part of the variable swirl system to facilitate the desired variations of the in-cylinder swirl.
Figure 3 illustrates the perspective view of the configuration of sector valve 12, wherein the sector valve 12 has a prismatic shape and is preferably configured with a cover 4 welded to the shaft 3. With this configuration, the valve 12 can be rotated about the axis of the shaft 3 to selectively open or close the upstream port 2 or downstream port 7 as per the desired swirl ratio for increasing or decreasing the momentum of the in-cylinder air for better mixing of air and fuel.
Figure 4 illustrates the closing of the upstream port when air travels via path shown by arrow 15.
Figure 5 illustrates the closing of the downstream port when air travels via path shown by the arrow 17.
As illustrated in Figure 4 and 5, the position of the sector valve can be changed in order to keep either of these ports fully open or closed, including any of their intermediate positions during the valve lift. The position of the sector valve can also be changed during the inlet valve lift of either of the valves.

TECHNICAL ADVANCEMENTS AND ECONOMIC SIGNIFICANCE
The technical advantages of the variable swirl system include the following:
In the prior art systems, there existed a problem of reduced flow of air to the engine cylinder, because even though the valve is completely opened, it causes some restriction in the air path. It is also desirable that there should be complete control over opening and closing of both the ports during the valve lift, this is not possible in present systems. The present application seeks to address this problem existing in the state of the art, by exploiting the disposition of Siamese twin inlet ports, thereby enabling an easy control of swirl by opening or closing the individual inlet ports. The central position of Sector valve can be used to reduce the effect of reduced flow of air. These are typically used in internal combustion engines for automotive or generator set applications. Thereby, the smoke and emissions can be reduced using.
The numerical values given for various physical parameters, dimensions and quantities, are only approximate values and it is envisaged that the values higher or lower than the numerical value assigned to these physical parameters, dimensions and quantities also fall within the scope of the invention, unless there is a statement in the specification to the contrary.
Wherever a range of values is specified, a value up to 10% below and above the lowest and highest numerical value respectively, of the specified range, is included within the scope of the invention.

While considerable emphasis has been placed herein on the particular features of this invention, it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiment without departing from the principles of the invention.
These and other modifications in the nature of the invention or the preferred embodiments will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation thereof.
Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression "at least" or "at least one" suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the invention to achieve one or more of the desired objects or results.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the invention as it existed anywhere before the priority date of this application.

The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.

We claim:
1. Variable swirl system disposed in a cylinder head (10) of an internal combustion engine, comprising Siamese twin inlet ports comprising a downstream port (2) and an upstream port (7) sharing a common wall and a sector valve (12) which can be suitably positioned in order to simultaneously vary the swirl levels in said twin inlet ports (2, 7) by increasing or decreasing the momentum of the in-cylinder air for better mixing of air and fuel.
2. Variable swirl system as claimed in claim 1, wherein said sector valve (12) comprises a prismatic cover (4) welded to a shaft (3) supported on bearing at both the ends (5) thereof.
3. Variable swirl system as claimed in claim 1, wherein said sector valve (12) is positioned to open or close one of said inlet ports (2, 7) for varying the in-cylinder swirl strengths during a small period of the valve lift by means of rotation of said prismatic cover (4) about the axis of said shaft (3).
4. Variable swirl system as claimed in claim 1 or 2, wherein the sector valve (12) opens or closes at least one of said inlet ports (2, 7), either fully, or partially, at a very high frequency to control the mass of air entrained in the cylinder by means of the suction effect of air.
5. Variable swirl system as claimed in claim 1, wherein said variable swirl system can be used both for spark ignition or gasoline engines to control the tumbling motion of the air inside the cylinder of said engine.

6. Variable swirl system as claimed in anyone of the preceding claims,
wherein the position of said sector valve (12) can be changed electronically by
an actuator driven by means of an electronic control unit by sensing the
manifold air pressure or the fuel pump rack position and the rpm of said
engine.
7. Variable swirl system as claimed in anyone of the preceding claims,
wherein the position of said variable sector valve (12) can be changed either
pneumatically or hydraulically by using engine oil from the lubricating circuit
of said engine.