FIELD OF THE DISCLOSURE
The present disclosure relates to internal combustion gasoline engines.
More specifically, the present disclosure relates to an intake system for internal combustion gasoline engines using a carburetor per cylinder.
BACKGROUND
An intake system for internal combustion engines includes an air filter, a connecting tube, a carburetor, an intake manifold and an intake port which leads the air and fuel mixture to a combustion chamber. The power and torque required for driving a motor vehicle and the like, is developed in the cylinder of the engine by combustion of the fuel. The requirement of power and torque during engine operating condition depends on load encountered, for example, in the case of motor vehicles the load depends upon various factors like road conditions and weight of the vehicle and the like. To cater the power requirements at different load conditions, the intake conditions has to be varied by accelerator control as the power and the torque developed by the engine, largely depends upon the amount of charge taken in the cylinder through the carburetor plunger opening.
Conventionally, the plunger position of carburetor determines the engine operating range. The engine operating range is determined by the mechanical movement of a plunger that regulates the power and torque generated by the engine.
Particularly, in case of motor vehicles the requirement of power and torque such as in normal city driving conditions is achieved at lower engine speeds at a part open throttle condition and such as on highways it is achieved at higher engine

speeds at a wide open throttle condition. The engine power and the torque developed throughout the travel of carburetor plunger depend on various factors; one among them being the length and geometry of the intake manifold.
Various efforts have been made to achieve two peaks of the torque, one occurring at lower engine speed and one occurring at higher engine speed by changing e.g. the exhaust system characteristics. Also, efforts have been made to provide twin passages in the intake manifold wherein the flow to one of the passage is controlled with the help of a butterfly valve actuated through externally provided hydraulic, pneumatic or electric means. This however adds to cost, increased complexity, increased number of moving parts, decreased reliability, restriction in the flow path and the like.
Hence, there is felt a need for a system that can provide higher torque at both part open throttle conditions and at wide open throttle condition.
OBJECTS
Some of the objects of the system of the present disclosure, which at least one embodiment herein satisfies, are as follows:
An object of the present disclosure is to provide an intake system that enables good spread of torque throughout the engine operating range.
Another object of the present disclosure is to provide an intake system that is simple in construction.
Further, an object of the present disclosure is to provide a system that is reliable.
Still another object of the present disclosure is to provide a system that is free of actuation mechanism.

Yet another object of the present disclosure is to provide a system that is free of moving parts.
An added object of the present disclosure is to provide a system that facilitates improved combustion of fuel within an IC engine.
Another object of the present disclosure is to provide a system that is adaptable in compact space.
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 disclosure.
SUMMARY
In accordance with the present disclosure there is provided an intake manifold for conveying air-fuel mixture from an inlet to an outlet, the inlet and the outlet being connected to the carburetor and the cylinder head respectively, the carburetor includes a plunger to regulate the opening of the inlet between a completely closed configuration and a completely open configuration, the manifold characterized by:
• a long duct fluidly communicating the inlet to the outlet;
• a short duct fluidly communicating the inlet to the outlet; and
• a junction defined adjacent to the inlet, the long duct and the short duct positioned in a manner, such that,
when the plunger is displaced to fully open the inlet, at least 80% of the air-fuel mixture flows through the short duct,

when the plunger is displaced to open the inlet by 50% to fully open the inlet, the air-fuel mixture in the range of 30% to 80% flows through the short duct, and
when the plunger is displaced to block the inlet by 50% or more, at least 70% of the air-fuel mixture flows through the long duct.
The short duct is disposed substantially above the junction.
The long duct is disposed substantially below the junction.
The long duct and the short duct enable flow of a part of the air-fuel mixture in the completely open configuration and the completely closed configuration.
The flow of the air-fuel mixture through the long duct and the short duct define a predetermined angle therebetween.
The junction is profiled to selectively divert flow of air-fuel mixture through the long duct and the short duct corresponding to the plunger position.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
The intake manifold for automotive vehicles of the present disclosure will now be described with the help of accompanying drawings, in which:
Figure 1 illustrates a perspective view of the intake system for internal combustion engine in accordance with one embodiment of the present disclosure;
Figure 2 illustrates a perspective view of the intake manifold of the intake system of Figure 1 having a first path and a second path;
Figure 3 illustrates a cross-sectional perspective view of the intake system of Figure 1 illustrating the junction of the first path and the second path of Figure 2;

Figure 4 illustrates a cross-sectional perspective view of the intake system of Figure 1 depicting the flow of air-fuel mixture at partial open condition of the throttle;
Figure 5 illustrates an another perspective view of the intake system of Figure 1, depicting the flow of air-fuel mixture at part open throttle condition;
Figure 6 illustrates a cross-sectional perspective view of the intake system of Figure 1, depicting the flow of air-fuel mixture at fully open condition of the throttle; and
Figure 7 illustrates a graphical representation depicting the variation of Torque in Newton-meter with respect to engine speed in revolution per minute (rpmj for the intake system of Figure 1.
DETAILED DESCRIPTION
A system of the present disclosure will now be described with reference to the embodiments which do not limit the scope and ambit of the disclosure.
The embodiments 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 intake system for automotive vehicles in accordance with the present disclosure is described herein below with respect to Figure 1 wherein the key components of the intake system are generally referenced by numerals as indicated.
Figure 1 illustrates a perspective view of an intake system 1000 for an internal combustion engine. The intake system 1000 includes a carburetor 100, an intake manifold 200, a cylinder head 300 including an intake port, an air filter member 400 and a connecting tube 500. The Figure 2 particularly illustrates the intake manifold 200 in accordance with the present disclosure.
Figure 2 illustrates a perspective view of the intake manifold 200, in accordance with the present disclosure, cooperating with the carburetor 100 through mounting arrangements 103. The intake manifold 200, illustrated in Figure 3, includes an inlet 106 and an outlet 206 fluidly communicating via a long duct 201and a short duct 202.
The carburetor 100 includes a plunger 101, a fuel reservoir 104 and a mounting provision 102 for mounting the carburetor 100 on the connecting tube 500. The plunger 101 is mechanically displaceable by accelerator control. The displacement of the plunger 101 enables regulating the opening of the inlet 106 between a fully closed condition, an intermediate condition and a wide-open condition. Intake air, filtered in the air filter member 400, is introduced into the carburetor 100. The intake air is mixed with the fuel contained in the fuel reservoir 104 to form a desired air-fuel mixture corresponding to the fuel requirement of an Internal Combustion (IC) engine at a lower speed and a higher speed of operation of the IC engine.

In the closed condition of the plunger 101, the opening of the inlet 106 is closed to flow of air-fuel mixture. In the intermediate condition of the plunger 101, the opening of the inlet 106 is partially open to enable flow of air-fuel mixture therethrough. In the wide-open condition of the plunger 101, the opening of the inlet 106 is fully open to enable flow of air-fuel mixture therethrough.
The air-fuel mixture enters the intake manifold 200 through the inlet 106 from the carburetor 100. The long duct 201 and the short duct 202 diverge from a junction 205 within the inlet 106. The long duct 201 defines a flow path which is substantially longer than that of the short duct 202. The long duct 201 and the short duct 202 enable conveying the air-fuel mixture from the inlet 106 to the outlet 206 depending on the requirement of the IC engine. When the IC engine operates at a lower speed, the air-fuel mixture is conveyed from the inlet 106 to the outlet 206 via the long duct 201. On the other hand, when the engine operates at a higher speed, the air-fuel mixture is conveyed from the inlet 106 to the outlet 206 via the short duct 202.The outlet port 206 communicates the air-fuel mixture to the intake port of the cylinder head 300 and hence supplies the required air-fuel mixture to the IC engine.
The inlet 106 splits into the long duct 201 and short duct 202 at the junction 205 downstream of the inlet 106. The long duct 201 and the short duct 202 is positioned in a manner, such that, when the plunger 101 is displaced to fully open the inlet 106, at least 80% of the air-fuel mixture flows through the short duct 202 while the remaining flow of the air-fuel mixture take place through the long duct 201. Further, when the plunger 101 is displaced the intermediate position so as to block the inlet 106 by 50% or more, at least 70% of the air-fuel mixture flows through the long duct 201. When the plunger 101 is displaced to open the inlet 106 by 50% to fully open the inlet 106, the air-fuel mixture in the range of 30% to 80% flows through the short duct 202. The junction 205 is

profiled such that the flow of the air-fuel mixture through the long duct 201 and the short duct 202 define a pre-determined angle therebetween such that the short duct 202 is positioned substantially above the long duct 201.
Figure 4 and Figure 5 depict the flow of the air-fuel mixture through the intake manifold 200 when the plunger 101 of carburetor 100 is in the intermediate position. When the plunger 101 of carburetor 100 is in the intermediate position, the opening of the inlet 106 is partially open. The air-fuel mixture passes through the partial opening of the inlet 106 and is guided into the long duct 201 because of the profile of the junction 205 such that a substantial portion of the air-fuel mixture is conveyed through the long duct 201 to the outlet 206. This enables conveying the air-fuel mixture to the intake port for enabling efficient operation of the IC engine under conditions wherein high torque is required at lower speed operation of the IC engine. A minimal portion of the air-fuel mixture flows through the short duct 202 to the outlet 206. The air-fuel mixture from the short duct 202 mixes with the air-fuel mixture flowing through the long duct 201 at the outlet 206 of the intake manifold 200. The motion of air-fuel mixture through long duct 201 creates turbulence at the outlet 206 for efficient combustion in the combustion chamber. The position of the plunger 101 of carburetor 100 in the intermediate position restricts the flow of the substantial portion of the air-fuel mixture through the short duct 202, while the profile of the junction 205 enables flow of the substantial portion of the air-fuel mixture through the long duct 201.
Figure 6 depicts the flow of the air-fuel mixture through the intake manifold 200 when the plunger 101 of carburetor 100 is in the wide open position. When the plunger 101 of carburetor 100 is displaced to the wide open position, the opening of the inlet 106 is fully open. The air-fuel mixture from the carburetor 100 passes through the inlet 106. A substantial portion of the air-fuel mixture is

guided into the short duct 202 because of the profile of the junction 205 while a minimal portion of the air-fuel mixture flows through the long duct 201. The air-fuel mixture is conveyed to the outlet 206. The portion of the air-fuel mixture flowing through the long duct 201 mixes with the substantial portion of the air-fuel mixture flowing through the short duct 202 at the outlet 206 of the intake manifold 200. The air-fuel mixture flowing through the short duct 202 facilitates quicker filling of combustion chamber, thus creating turbulence of air-fuel mixture. This enables efficient operation of the IC engine under conditions wherein high torque is required while the engine operates at a higher speed. The minimal portion of the air-fuel mixture through the long duct 201 is essentially due minimal restriction to flow of the air-fuel mixture in the short duct 202. Due to minimum restriction to the flow of the air fuel mixture through the short duct 202, the portion of the air-fuel mixture flowing through the long duct 201 is kept to the minimum.
Thus, the intake manifold 200, as envisaged by the present disclosure, enables selectively directing the air-fuel mixture through the long duct 201 at partially open condition of the inlet 106 and through the short duct 202 at fully open condition of the inlet 106. This helps in achieving good spread of torque throughout the operating range of the IC engine.
TRAIL RESULTS
The intake manifold of the present disclosure mounted on an IC engine was tested for variation of the Torque in (Newton-meter) with respect to engine speed in revolution per minute (rpm). Figure 7 illustrates a typical graphical representation depicting the variation of the Torque in (Newton-meter) with respect to engine speed in revolution per minute (rpm) for the intake manifold of the present disclosure and conventional intake systems.

In Figure 7, curves al and a2, graphically represents Torque in Newton-meter Vs Engine speed (rpm), as produced by an IC engine wherein an intake system with the intake manifold of the present disclosure is installed, when the inlet 106 is in fully open condition and in partially open condition respectively. Again, curves bl and b2 in Figure 7 represent the curve of Torque in Newton-meter Vs Engine speed (rpm) as produced by a conventional Intake system mounted on an IC engine operating in fully open condition and partially open condition respectively.
From Figure 7, it can be observed that in partially open condition of the inlet of the intake manifold of the present disclosure and the conventional intake manifold, the curve a2 illustrates significant improvement in torque of the IC engine as compared to b2. Again, in the fully open condition of the throttle, the curve al illustrates that the intake manifold of the present disclosure generates torque which is substantially similar to that generated by conventional intake manifold as illustrated by the curve bl. Thus, the intake system of the present disclosure provides significant improvement in torque at partially open condition of the throttle without compromising with the performance of the IC engine at fully open condition of the throttle.
TECHNICAL ADVANCEMENTS
The present disclosure described herein above has several technical advantages including but not limited to the realization of:
• an intake manifold that is capable of directing the flow through long and short duct at part and wide open throttle condition respectively;
• an intake manifold that enables good spread of torque throughout the engine operating range;
• an intake manifold that is simple in construction;

• an intake manifold that is reliable;
• an intake manifold free of actuation mechanism;
• an intake manifold with no moving parts;
• an intake manifold facilitating improved combustion of fuel within an IC engine; and
• an intake manifold adaptable in compact space.
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 disclosure to achieve one or more of the desired objects or results.
The numerical values given of 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 the physical parameters, dimensions and quantities fall within the scope of the disclosure 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 in the scope of the disclosure.
The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the

singular forms "a", "an" and "the" may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises," "comprising," "including," and "having," are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.
When an element or layer is referred to as being "on", "engaged to", "connected to" or "coupled to" another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly engaged to", "directly connected to" or "directly coupled to" another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., "between" versus "directly between," "adjacent" versus "directly adjacent," etc.). As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as "first," "second," and other numerical terms when used herein do not imply a

sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.
Spatially relative terms, such as "inner," "outer," "beneath", "below", "lower", "above", "upper" and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the example term "below" can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
The foregoing description of the specific embodiments 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.

WE CLAIM:
1. An intake manifold for conveying air-fuel mixture from an inlet to an outlet,
the inlet and the outlet being connected to the carburetor and the cylinder
head respectively, the carburetor includes a plunger to regulate the opening
of the inlet between a completely closed configuration and a completely
open configuration, said manifold characterized by:
• a long duct fluidly communicating the inlet to the outlet;
• a short duct fluidly communicating the inlet to the outlet; and
• a junction defined adjacent to the inlet, said long duct and said short duct positioned in a manner, such that,
when the plunger is displaced to fully open the inlet, at least 80% of the air-fuel mixture flows through said short duct,
when the plunger is displaced to open the inlet by 50% to fully open the inlet, the air-fuel mixture in the range of 30% to 80% flows through the short duct, and
when the plunger is displaced to block the inlet by 50% or more, at least 70% of the air-fuel mixture flows through said long duct.
2. The manifold as claimed in claim 1, wherein said short duct is disposed substantially above said junction.
3. The manifold as claimed in claim 1, wherein said long duct is disposed substantially below said junction.
4. The manifold as claimed in claim 1, wherein said long duct and said short duct enables flow of a part of the air-fuel mixture in the completely open configuration and the completely closed configuration.

5. The manifold as claimed in claim 1, wherein the flow of the air-fuel mixture through said long duct and said short duct define a predetermined angle therebetween.
6. The manifold as claimed in claim 1, wherein said junction is profiled to selectively divert flow of air-fuel mixture through said long duct and said short duct corresponding to the plunger position.