FIELD OF THE INVENTION

The present invention relates to a novel construction of the manifold for intake system of an automotive engine. The novelty of the invention lies in the construction of the manifold, more particularly in the design of outlet of the said manifold that is adapted to offset the imbalance in flow of charge (air fuel mixture) through the ports, using guiding structures at the outlet.

BACKGROUND AND PRIOR ART

US4470377 entitled "Intake manifold for an internal-combustion engine with spark ignition" describes an intake manifold for a spark-ignited internal combustion engine including a distributor body from which the intake pipes leading to the individual combustion chambers of the engine branch off in a sequence corresponding to the firing order. The individual intake pipes depart, via branch lines, from more than one location of the distributor body.
WO2010112719 entitled "Control system and method for estimating the flow rate of recycled exhaust gases in an internal combustion engine" discloses a system for controlling an internal combustion engine provided with: two intake manifolds, i.e. a main manifold and a secondary manifold and for adjusting the flow rates of gases entering the cylinders of the engine, an intake valve upstream of the two manifolds and a swirl valve between the intake valve and the secondary manifold.

US4886034 entitled "Internal combustion engine control system" discloses an engine provided with a biased by-pass throttle valve that trims the flow of supplementary combustion air for mixing with basic combustion air and fuel induced in carburetor venturi. The by-pass throttle valve is controlled by an electrical step-motor that is regulated by a pre-programmed microprocessor in response to sensed engine speed and engine manifold pressure conditions to thereby improve engine operating efficiency and reduce noxious emissions without utilizing catalytic converter equipment.

In recent years, an automotive internal combustion engine, with multiple intake ports for each cylinder has been developed to improve charging efficiency of intake air so as to increase engine power. An intake system, used for such multi-port automotive internal combustion engine as having two or more intake ports, may use a single manifold to supply charge to these ports, however, the drawback with such an arrangement is that, the flow of charge through the ports is imbalanced and one of the valves is deprived of the charge, owing to the physical positioning of valves and throttle position at different operating conditions, this may lead to gumming of the starved valve and decrease in intake efficiency of the system. Thus, it is desirable to offset this charge unbalancing effect.

Thus there is a requirement for a new system of an automotive engine such that the imbalance in charge flow through said ports can be managed.

SUMMARY OF THE INVENTION

This invention relates to manifold for the intake system for a two-intake port automotive engine, said manifold has an inlet configured to receive the fuel air mixture, ( hereinafter charge ) from the throttle body and an outlet to discharge the charge into the combustion chamber of the engine, through the two intake ports. In the present invention said outlet is adapted to offset the imbalance in flow of charge through the two intake ports.
In especially preferred embodiment the outlet of the manifold is partitioned by a guide defining the dedicated pathways for the two intake ports. The guide is structured and positioned to offset the imbalance in flow of charge through the two ports.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 illustrates the pictorial representation of a step-through, two-wheeled vehicle embodying present invention.

Figure 2 illustrates the pictorial representation of an engine attached along with the induction system mounted on a vehicle frame.

Figure 3 illustrates a cylinder head of a four-stroke engine having three valves.

Figure 4 illustrates the cross section view of the cylinder head showing the coupling arrangement for manifold.

Figure 5 and Figure 6 illustrates the prospective views of the manifold.

Figure 7 illustrates the cross sectional views of the manifold taken along the line AA of Fig. 5.

Figure 8 illustrates the cross sectional views of the manifold taken along the line BB of Fig. 5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Figure 1 illustrates a two-wheeled motor vehicle, indicated by reference numeral 1, that is a step through type two-wheeled motor vehicle mainly composed of a body frame 2, a front fork 8 attached to a head pipe 3 of the body frame 2, a front wheel 7 secured to the front fork 8 along with the mud shield 4 and a handle bar 11 further attached to the front fork. Furthermore, an engine with induction system 9 is mounted to a rear portion of the body frame 2, a rear wheel 6 is secured to the body frame 2 in a vertically swing able manner using a swing arm 5. In addition, rear cushion units 10 suspend a rear end position of the swing arm from the body frame 2.

Figure 2 illustrates the engine with induction system 9 secured to the body frame 2 of motor vehicle 1, that includes an air filter 12 to provide clean air to the carburetor 13 that mixes the fuel with the air, and finally the air fuel mixture is discharged to the intake ports of the engine 14 through the intake manifold (not shown in figure).

Figure 3 illustrates the cylinder head 15 of the three-valve engine 14 wherein, the combustion chamber 16 has three ports 17, 18, 19 as seen from inside the combustion chamber, of which ports 17 and 18 are intake ports and port 19 is the exhaust port.

Figure 4 gives a cross-sectional view of the engine cylinder head 15 wherein, the intake manifold 20 shown in Figure 5 connects in such a manner that the intake port 17 is coupled to dedicated pathway 22 of the manifold 20 and intake port 18 couples to dedicated pathway 24 of the manifold 20.

Figure 5 and Figure 6 illustrates the intake manifold 20 whereas Figure 7 and Figure 8 gives the cross sectional view of the manifold 20 that includes an inlet 25 configured to receive the charge from the carburetor 13, an outlet 21 configured to discharge the charge in to the cylinder head 15, an interior wall 26, and an intake passageway 27 defined by the interior wall, through which the charge passes, extending between the inlet 25 and the outlet 21. With additional reference to Figure 5 and Figure 8, the intake passageway has a non-linear longitudinal axis, such that the charge passing through the intake passageway 27 travels a substantially arcuate flow path moving from the inlet 25 to the outlet 21. Alternative constructions of the intake manifold may include any of a number of different configurations, in which the longitudinal axis of the intake passageway is substantially arcuate or substantially straight or linear.

In the present embodiment of the invention the outlet 21 of the manifold 20 is partitioned by a guide 23 that defines the dedicated passageways 22 and 24 along with the wall 26 of intake passageway 27, for the two intake ports 17 and 18 respectively. The said guide is positioned, so as to divide the outlet 21 in a specific ratio wherein, the guide 23 starts from the outlet 21 and extends inwards into the intake passageway 27, with the wall 28 towards the dedicated pathway of larger capacity, gradually tapering along the length as said guide 23 extends inwards. (The specific ratio with which the outlet is divided depends on the engine design and other parameters). The inwards tapered side 28 of the guide 23 enables more charge to flow through the dedicated pathway 24 of larger capacity compared to the other pathway thus, offsetting for the imbalance in flow of charge through the two ports.
Although the present invention has been described and illustrated in detail, it is to be clearly understood that the same is by way of illustration and example only, and is not to be taken by way of limitation. The spirit and scope of the present invention are to be limited only by the terms of the appended claims.

WE CLAIM

1. A manifold assembly for a two-intake valve internal combustion engine including an inlet 25, an outlet 21 with a guide 23 which dissects the said outlet thereby defining a plurality of passageway 22 and 24; the guide 23 starts from outlet 21, extends inwardly into intake passageway 27, ends with a wall 28, said wall being tapered so as to offset the imbalance in flow of charge through the ports of the engine.

2. The manifold assembly for a two-intake valve internal combustion engine of claim 1, wherein it enables more charge to flow through the plurality of passageway 24 by the inwards tapered side 28.

3. A method of offsetting the imbalance in flow of charge through the ports of the engine characterized in a manifold assembly for a two-intake valve internal combustion engine of an automotive vehicle including an inlet 25, an outlet 21 with a guide 23 in a specific ratio defining a plurality of passageway; the plurality of passageway tapering along the length extending the guide 23 inwards and an intake passage way 27 by the interior wall having a non-linear longitudinal axis so as to offset the imbalance in flow of charge through the ports of the engine comprising the steps of:

(i) Receiving the charge from the carburetor 13 by the inlet 25;

(ii) Passing the charge through the plurality of passageway 27
traveling a substantially accurate flow path;

(iii) Passing the charge through the plurality of passageway of larger capacity in the outlet 21 partitioned by guide 23;

(iv) Differentiating charge mixture to flow through the plurality of passageway 24 by the inwards tapered side 28;

(v) Offsetting for the imbalance in flow of charge through the two
ports; and (vi) Discharging the charge mixture in the cylinder head 15.

4. The method as claimed in claim 3 wherein it enables more charge to flow through the plurality of passageway 24 by the inwards tapered side 28.