US20090090101A1

US20090090101A1 - Exhaust Gas-Discharging Device of Vehicle

Info

Publication number: US20090090101A1
Application number: US12/225,872
Authority: US
Inventors: Soo Won Kim
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-04-04
Filing date: 2007-04-04
Publication date: 2009-04-09
Also published as: KR20070099259A; EP2002095A1; WO2007114646A1; JP2009542948A; CN101415916A; CN101415916B; CA2648206A1; KR100766806B1; EP2002095A4

Abstract

An exhaust gas discharge device for vehicles is disclosed. The exhaust gas discharge device of the present invention includes an extension pipe (10), which is fitted over a tail pipe of a silencer of a vehicle. A venturi passage (20) is defined in an exhaust gas inlet end of the extension pipe to increase a flow speed of the exhaust gas. The exhaust gas discharge device further includes an outside air discharge nozzle (30), which extends into the venturi passage, a backflow inlet port (40), which is provided in an exhaust gas outlet end of the extension pipe to guide outside air, and a cover (50), which defines therein a chamber, through which the backflow inlet port communicates with the outside air discharge nozzle. Thus, the present invention restrains backflow of exhaust gas using the flow of outside air, thus preventing back pressure, and rapidly discharging the exhaust gas, thereby enhancing the output of the engine.

Description

TECHNICAL FIELD

The present invention relates, in general, to exhaust gas discharge devices for discharging exhaust gas, used in internal-combustion engines for vehicles, and more particularly, to an exhaust gas discharge device for vehicles which is coupled to a tail pipe of a silencer provided in an exhaust gas discharge path of a vehicle and is constructed such that the backflow of exhaust gas is restrained by the flow of air, thus preventing back pressure, and rapidly discharging the exhaust gas, thereby reducing fuel consumption and enhancing the output of the engine.

BACKGROUND ART

As well known to those skilled in the art, in an internal-combustion engine of a vehicle, power is obtained through a four-stroke cycle including an intake stroke, a compression stroke, an explosion stroke and an exhaust stroke.
With regard to the flow of gas (intake air and discharge air) during the strokes of the engine, in the intake process, gas is drawn into the engine after passing through an air cleaner and a throttle valve with little resistance.
However, in the exhaust process, because exhaust gas is discharged outside the vehicle via an exhaust manifold, a gas purification device comprising a catalyst, and a silencer, there is a relatively large amount of resistance to the discharge air flow.
During the process in which gas is discharged from the cylinder of the engine to the tail pipe of the silencer, a valve overlap, in which an intake valve and an exhaust valve are momentarily opened at the same time in the exhaust manifold, occurs in the four-stroke cycle of the engine. At this time, exhaust gas, which is being discharged, is drawn back into the cylinder, so that the exhaust manifold momentarily enters a vacuum state, thereby forming primary back pressure that interferes with the discharge of exhaust gas.
Furthermore, in a three-dimensional catalytic device, which is a gas purification device, the flow speed of exhaust gas is markedly reduced while it passes through the gas purification device, having a honeycomb shape, thus creating secondary back pressure. In addition, when exhaust gas, which is drawn into the silencer, passes through multi-stepped partition plates to absorb noise, tertiary back pressure is created.
In this gas discharge process, because exhaust gas is discharged at a pressure of approximately 3 to 5 kg/cm²and at a temperature of approximately 600° C., the silencer is essential. Typically, the silencer is designed to have a capacity that is fifteen to twenty times larger than the engine displacement. However, such a silencer has a disadvantage in that exhaust gas is not smoothly discharged from the engine due to air resistance, thus reducing the output of the engine by 5% to 10%.
Therefore, it is to be appreciated that the output of the engine can be enhanced and fuel consumption can be reduced merely by smoothly discharging exhaust gas.
To achieve the smooth discharge of exhaust gas, various conventional techniques were proposed.
As a representative example, an exhaust gas discharge device for vehicles using the flow of air was proposed in Korean Patent Laid-Open Publication No. 2000-56951. This technique, using the flow of air, is constructed such that the streamline-shaped body of the exhaust gas discharge device is coupled to a tail pipe, so that when the vehicle travels, a low pressure region is formed around the exhaust gas discharge device by the flow speed of air that passes along the surface of the streamline-shaped body, so that exhaust gas is sucked out by the lower pressure, thus promoting the discharge of exhaust gas.
However, this technique is disadvantageous in that the streamline-shaped body has a relatively large and complex structure affecting the installation thereof, and, when the vehicle is stopped or travels at a relatively low speed, because rapid air flow cannot be induced, the narrow discharge passage interferes somewhat with the discharge of exhaust gas. Therefore, it is very difficult to use this technique in practice.
Meanwhile, as another example of the conventional arts, in a tail pipe of a main silencer having a vortex generator, which was proposed in Korean Patent Laid-Open Publication No. 1998-75223, a vortex generating blade is provided at a medial portion in the tail pipe so as to be rotatable by exhaust gas. This technique is constructed such that the blade is rotated by exhaust gas, thus generating vortexes, thereby promoting the discharge of exhaust gas. However, there is a problem in that the blade serves as a source of some resistance that interferes with the flow of exhaust gas, and thus it cannot be used in practice.
As another example of conventional arts, in an exhaust gas discharging device for vehicles, which was proposed in Korean Utility Model Registration No. 99434, an exhaust gas discharge device is coupled to a tail pipe using locking bolts, and a plurality of vortex generating blades is radially provided on the circumferential inner surface of the pipe. This exhaust gas discharging device was proposed to achieve an improvement in discharge efficiency. However, it is difficult to rapidly and smoothly discharge exhaust gas using only vortexes generated in the exhaust gas. In other words, there is only a slight effect in which vortexes of fluid partially assist the discharge of exhaust gas, which is naturally discharged by exhaust pressure. As such, the efficiency of the device is very low.
Furthermore, as another example of the conventional arts, in an exhaust gas discharging device using vortexes, which was proposed in Korean Patent Registration No. 257874, a vortex generating duct, which includes a vane that draws outside air and generates vortexes, is provided on the front pipe of a silencer, which is provided in an exhaust gas discharge path. The exhaust gas discharging device further includes a sub duct, which has therein a valve that adjusts the degree of opening thereof in proportion to the opening degree of a throttle valve.
However, in this technique, because the duct is provided on the front pipe of the silencer, which serves to reduce exhaust noise, exhaust noise is transferred outside through the duct. Moreover, when the vehicle accelerates, the degree of opening of the valve is increased, and thus exhaust noise becomes severe. Furthermore, because exhaust gas is discharged through the sub duct, which has low air resistance compared to the interior of the silencer, outside air cannot be smoothly supplied into the duct because of the resistance. Therefore, it is also difficult to use this technique in practice.
In addition, in this technique, because outside air is drawn into an inlet of the silencer, air resistance still occurs in the silencer, and thus it is not useful for increasing the exhaust rate. As well, the device is provided with an air regulating damper, which is operated in conjunction with the throttle valve of the engine, so that there is a disadvantage in that the structure thereof is complex. Because outside air, drawn into the duct, passes through the silencer, foreign substances (dust, sand, etc.), which have been contained in the outside air, are deposited in the silencer, thus deteriorating the performance of the silencer.
In an effort to overcome the problems experienced with the conventional arts, an exhaust gas discharge device for vehicles was proposed in Korean Patent Registration No. 464711, which was filed by the inventor of the present invention.
This technique is constructed such that, when a vehicle travels, outside air is gathered using a flared tube, and is used to increase the exhaust pressure in a tail pipe, thus increasing the flow speed of exhaust gas.
That is, outside air is supplied into the flared tube to rapidly discharge exhaust gas outside the exhaust pipe using a phenomenon in which the pressure of air is increased when the air flows through a reduced area.
This technique realizes an increase in the flow speed of exhaust gas, thus having advantages of enhancing the output of the engine and reducing fuel consumption. However, there is a disadvantage in that, when the vehicle is stopped or travels at a low speed, the effect of this technique is markedly reduced.
Furthermore, a technique was proposed in Korean Patent Application No. 2004-13721, which was filed by the inventor of the present invention, the technique relating to a structure such that two stationary vanes are formed in a tail pipe by cutting and bending portions of the sidewall of the tail pipe inwards, so that the discharge of exhaust gas is promoted, and outside air, which is drawn backwards when the engine is in the valve overlap state, is discharged outside through the vane, thus increasing the output of the engine. Furthermore, a circulation exhaust gas discharge device was proposed in Korean Utility Model Registration No. 374553, which was filed by the inventor. In this circulation exhaust gas discharge device, first and second stationary vanes 1 and 2, each of which has a streamlined shape, are formed in the tail pipe of a silencer of a vehicle by cutting and bending portions of the sidewall of the tail pipe inwards. The first and second stationary vanes are disposed at positions spaced apart from each other by a predetermined distance, and face each other. In addition, the circulation exhaust gas discharge device includes a housing 3, which covers the first and second stationary vanes such that the first and second stationary vanes communicate with each other therethrough and are isolated from the atmosphere thereby. Thus, this exhaust gas discharge device promotes an increase in the flow speed of exhaust gas at the discharge end of the silencer. The inventor of the present invention proposed the above-mentioned techniques and several other techniques, which pertain to the exhaust gas discharge device.
The present invention is provided to improve the functions of the conventional techniques proposed by the inventor.

DISCLOSURE

[Technical Problem]

Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and has the following objects.
An object of the present invention is to provide an exhaust gas discharge device for vehicles, in which exhaust gas discharged through a tail pipe of a silencer is increased in speed by a venturi phenomenon, and outside air drawn thereby is circulated and discharged, thus accelerating the exhaust speed of exhaust gas, thereby making it possible to discharge the exhaust gas more rapidly.
Another object of the present invention is to provide an exhaust gas discharge device for vehicles which is constructed such that exhaust gas can be rapidly discharged, and in addition, some exhaust gas, which flows backwards, can be discharged outside the tail pipe along with outside air, which is circulated and discharged, thus preventing exhaust gas from being drawn back into an engine or forming back pressure, thereby increasing the output of the engine.
A further object of the present invention is to provide an exhaust gas discharge device for vehicles which has a solid structure, thus markedly increasing the durability thereof, and can be applied to an existing vehicle without changing the construction of the existing silencer, thus having superior intercompatibility.
Yet another object of the present invention is to provide an exhaust gas discharge device for vehicles which markedly reduces the backflow of exhaust gas, thus preventing combustion residue, such as carbon, from being deposited, thus extending the lifetime of the engine, and maintaining the components of the exhaust system, including an expensive gas purification device, clear and in a normal state, thereby extending the lifetime of the components.

[Technical Solution]

In order to accomplish the above objects, the present invention provides an exhaust gas discharge device for a vehicle, comprising: an extension pipe fitted over the tail pipe of a silencer of the vehicle, with a venturi passage defined in an exhaust gas inlet end of the extension pipe to increase the flow speed of the exhaust gas; an outside air discharge nozzle extending into the venturi passage; a backflow inlet port provided in an exhaust gas outlet end of the extension pipe to guide the inflow of outside air; and a cover fitted over the extension pipe to define therein a chamber, through which the backflow inlet port communicates with the outside air discharge nozzle, so that the flow speed of exhaust gas is increased at the distal end of an exhaust gas discharge path and the backflow of exhaust gas is prevented, thus enhancing the output of the engine.

[Advantageous Effects]

As described above, in the present invention, the exhaust gas discharge device is additionally coupled to the tail pipe of a silencer, through which exhaust gas is discharged outside. Therefore, the present invention can be easily applied to an existing vehicle without changing the construction of the existing exhaust system. Furthermore, exhaust gas is rapidly discharged by a venturi phenomenon, and outside air, which is drawn into a chamber of the exhaust gas discharge device and is circulated and discharged outside the vehicle, prevents the backflow of exhaust gas and thus prevents back pressure, thereby improving exhaust efficiency and enhancing the output of the engine. In addition, the present invention is designed such that the structures of the outside air discharge nozzle and the backflow inlet port can be changed, so that design of the chamber for forming a low pressure state therein can be easily conducted. As well, the present invention has a solid structure, thus markedly increasing the durability thereof, and can be applied to an existing vehicle without changing the construction of the existing silencer, thus having superior intercompatibility. Moreover, the present invention markedly reduces the backflow of exhaust gas, thus preventing combustion residue, such as carbon, from being deposited, thus extending the lifetime of the engine, and maintaining components of the exhaust system, including an expensive gas purification device, clear and in a normal state, thereby extending the lifetime of the components.
Meanwhile, although the exhaust gas discharge device of the present invention is illustrated as being used in vehicles, it will be easily appreciated that the present invention can be applied to any mechanism using an internal-combustion engine provided with a silencer having a tail pipe.

DESCRIPTION OF DRAWINGS

FIG. 1 is a sectional view showing a conventional exhaust gas discharge device for vehicles, a patent application for which was filed by the inventor of the present invention;

FIG. 2 is a sectional view showing the construction of an embodiment of the present invention;

FIG. 3 is a sectional view taken along line A-A of FIG. 2;

FIG. 4 is a right side view of FIG. 2;

FIG. 5 is a sectional view showing the construction of another embodiment of the present invention;

FIG. 6 is a view illustrating the installation of the present invention;

FIG. 7 is a view showing the operation of the embodiment of FIG. 2 to illustrate the exhaust stream;

FIG. 8 is a view showing the operation of the embodiment of FIG. 5 to illustrate the exhaust stream; and

FIG. 9 is a sectional view showing the construction of a further embodiment of the present invention.

BEST MODE

Hereinafter, the present invention will be described in detail with reference to the attached drawings.
A preferred embodiment of the present invention is shown in FIGS. 2 through 4.
The exhaust gas discharge device 100 of the present invention includes an extension pipe 10, which is fitted over a tail pipe that is provided on the end of a silencer of a vehicle. A venturi passage 20, which has a relatively small diameter to thus increase the flow speed of exhaust gas, is defined in an exhaust gas inlet end of the extension pipe. Outside air discharge nozzles 30 extend from a surface, defining the venturi passage 20, towards the center of the venturi passage. Backflow inlet ports 40, through which outside air is drawn, are formed in an exhaust gas outlet end of the extension pipe. The circulation exhaust gas discharge device 100 further includes a cover 50, which is fitted over the extension pipe to define therein a chamber 52, through which the backflow inlet port 40 communicates with the outside air discharge nozzle 30.
Meanwhile, as shown in FIG. 5, the present invention may further include a subsidiary venturi passage tube 22, which is provided in the venturi passage 20, and the opposite ends of which are increased in diameter. Furthermore, the present invention may be constructed such that the outside air discharge nozzles 30 extend predetermined lengths into the subsidiary venturi passage tube 22, so that the ends of the nozzles communicate with the subsidiary venturi passage tube 22, and the subsidiary venturi passage tube 22 is supported by the nozzles 30 at the center of the venturi passage 20.
The outside air discharge nozzles 30, which extend from the extension pipe 10 into the venturi passage 20, are inclined in the direction in which exhaust gas is discharged. Each nozzle comprises an inclined pipe, the diameter of which is reduced from the chamber 52 to its discharge end, through which air is discharged.
Preferably, the number of outside air discharge nozzles 30 may be selected from among two through four outside air discharge nozzles 30 (refer to FIG. 3).
The backflow inlet ports 40, through which outside air is drawn, are provided in the exhaust gas outlet end of the extension pipe 10, and each comprise a pipe having a predetermined length. Preferably, the number of backflow inlet ports 40 may be selected among from two through four backflow inlet ports 40 (refer to FIG. 4).
In the drawings, the reference numeral 16 denotes slits, through which the extension pipe is coupled to the tail pipe of the silencer.
The operation of the present invention, having the above-mentioned construction, will be explained in detail herein below.
As shown in FIG. 6, the exhaust gas discharge device 100 of the present invention is fitted over and fastened to the circumferential outer surface of the tail pipe of the typical silencer 60 using a clamp or the like. As such, the installation of the present invention can be easily conducted.
Typically, after exhaust gas, which is generated by the operation of an engine through a typical process, is drawn into the silencer 60, noise is reduced in an expansion chamber of the silencer 60 and, thereafter, the exhaust gas is discharged outside the silencer.
As shown in FIG. 7, exhaust gas, which has been discharged from the silencer, is drawn into the extension pipe 10 of the exhaust gas discharge device 100 of the present invention. The exhaust gas thereafter passes through the venturi passage 20, the diameter of which is reduced, at an increased velocity, thus increasing the exhaustion velocity thereof, and simultaneously drawing air, which is in the chamber 52, through the outside air discharge nozzles 30, which extend into the venturi passage 20. Thus, the air is discharged along with the exhaust gas, so that the chamber enters a momentary low pressure state. After the exhaust gas is discharged, backflowing stream of the discharged exhaust gas is drawn into the chamber, which is in the low pressure state, through the backflow inlet ports 40.
Thus, the backflowing exhaust gas stream is not moved towards the engine and is again discharged outside through the chamber 52 of the exhaust gas discharge device. Here, this process, by which exhaust gas is guided to the venturi passage and discharged outside at a relatively high speed, is repeatedly conducted.
Therefore, exhaust gas, which is discharged along with negative pressure waves, serves to eliminate back pressure because negative pressure waves of the backflow are removed by the exhaust gas discharge device.
Here, in the operation of the engine, in which several tens or one hundred and several tens of intake processes and exhaust processes are repeated per second, several tens or one hundred and several tens of processes of discharging exhaust gas and processes of stopping the discharge of exhaust gas are also repeated. At this time, the exhaust system alternately and repeatedly enters a positive pressure state and a negative pressure state. In addition, when the exhaust system enters the negative pressure state while exhaust gas having exhaust inertia is discharged, the backward inflow of outside air is induced. In the conventional art, this outside air, which is drawn backwards, serves as back pressure, with the result that the output of the engine is reduced. However, in the present invention, in a state in which the discharge of exhaust gas is momentarily stopped, at the moment that exhaust inertia is applied, low pressure is formed in the chamber 52, so that outside air is drawn into the chamber 52 through the backflow inlet ports 40, which have low inflow resistance, thus removing back pressure, which is applied to the exhaust system by the backflow in the conventional arts.
Therefore, in the pipe of the silencer, through which exhaust gas is discharged, the discharge of exhaust gas is accelerated. Furthermore, when the engine is in the overlap state, because a backflowing exhaust gas stream is immediately re-discharged by the air circulation of the exhaust gas discharge device 100, including air intake and discharging processes, discharge flow is prevented from being interfered with the backflow, so that the discharge of exhaust gas can be smoothly conducted. Thus, the output of the engine is increased, and fuel consumption is reduced. As well, foreign substances, which remain in the exhaust system after combustion, can be smoothly removed, thereby preventing damage to components of the exhaust system, which are expensive, and extending the lifetime thereof.

MODE FOR INVENTION

The present invention, having the above-mentioned construction and operation may be modified, as shown in FIG. 5.
In detail, in the embodiment of FIG. 5, the air circulation operation, using a venturi passage 20 and a chamber 52, is the same as that of the prior embodiment. However, unlike the prior embodiment, the embodiment of FIG. 5 further includes a subsidiary venturi passage tube 22, which is provided in the venturi passage 20, so that outside air, which has passed through outside air discharge nozzles 30, is discharged through the subsidiary venturi passage tube 22. Thus, the discharge speed of exhaust gas, which is increased through the venturi passage 20, is further increased by the subsidiary venturi passage tube 22 (see, FIG. 8).
Each outside air discharge nozzle 30 comprises an inclined pipe, the diameter of which is reduced from the inlet end thereof, adjacent to the chamber 52, to the discharge end thereof, thus serving to increase the acceleration of discharged air. Furthermore, the outside air discharge nozzle 30 is inclined in the direction in which exhaust gas is exhausted, thus reducing resistance to the discharge flow of the exhaust gas.
Furthermore, backflow inlet ports 40 are disposed at the distal end of the exhaust gas discharge device to prevent outside air from being drawn into a gas discharge passage in an undesirable direction. The opening area of each backflow inlet port 40 can be appropriately adjusted such that, when outside air is discharged through the outside air discharge nozzles 30, a momentary low pressure state is formed in the chamber 52. Furthermore, two through four, preferably two, backflow inlet ports 40 are arranged in a circle at positions spaced apart from each other, as shown in the drawings.
The present invention, having the above-mentioned construction such that the discharge speed of exhaust gas is increased and back pressure applied to the exhaust system is removed, may be modified for ease of manufacture, as shown in FIG. 9.
In detail, the extension pipe, through which exhaust gas is discharged from the engine, is sectioned into a first pipe 12, which is disposed adjacent to the inlet of the extension pipe, and a second pipe 14, which is disposed adjacent to the outlet of the extension pipe. The first pipe 12 includes a bent part 12 a, which is formed by bending the end of the first pipe such that the diameter thereof is reduced to form a venturi passage, and a bent part 14 a is also formed in the end of the second pipe 14. The first pipe 12 and the second pipe 14 are coupled to each other through a cover 52, such that the bent parts 12 a and 14 a face each other, so that the bent parts 12 a and 14 a serve as both the venturi passage and a ring-shaped outside air discharge nozzle.
In this case, there is an advantage in that the outside air discharge nozzle can be easily provided in the venturi passage, and it is to be appreciated that the operation thereof is the same the basic embodiment of the present invention, described above.
Meanwhile, a connection plate 15, having a predetermined width, may be circumferentially welded to the circumferential outer surfaces of the first and second pipes 12 and 14, which are separated from each other, thus ensuring the structural strength of the extension pipe.
The structure of the exhaust gas discharge device, which includes the venturi structure such that the rapid discharge of exhaust gas is realized by increasing the flow speed of exhaust gas of the engine, the outside air discharge nozzle that extends into the venturi passage such that a low pressure state is formed in the chamber, and the backflow inlet port, can be variously modified, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. These modifications must be regarded as falling within the bounds of the claims of the present invention.

Claims

1. An exhaust gas discharge device for a vehicle, coupled to a tail pipe of a silencer of the vehicle to improve a flow of exhaust gas, and comprising:

an extension pipe, with a venturi passage defined in an exhaust gas inlet end of the extension pipe to increase a flow speed of the exhaust gas; an outside air discharge nozzle extending into the venturi passage; a backflow inlet port provided in an exhaust gas outlet end of the extension pipe to guide inflow of outside air; and a cover fitted over the extension pipe to define therein a chamber, through which the backflow inlet port communicates with the outside air discharge nozzle.

2. The exhaust gas discharge device for the vehicle according to claim 1, further comprising:

a subsidiary venturi passage tube provided in the venturi passage, the subsidiary venturi passage being increased in diameter at opposite ends thereof, wherein the outside air discharge nozzle extends a predetermined length into the subsidiary venturi passage tube (22), so that an end of the nozzle communicates with the subsidiary venturi passage tube, and the subsidiary venturi passage tube is supported by the outside air discharge nozzle (30) at a center of the venturi passage.

3. The exhaust gas discharge device for the vehicle according to claim 1, wherein the outside air discharge nozzle, which extends from the extension pipe into the venturi passage, is inclined in a direction in which the exhaust gas is discharged, and the outside air discharge nozzle comprises an inclined pipe, a diameter of which is reduced from the chamber to an air discharge end thereof.

4. The exhaust gas discharge device for the vehicle according to claim 1, wherein the outside air discharge nozzle and the backflow inlet port respectively comprise at least two outside air discharge nozzles and at least two backflow inlet ports.

5. The exhaust gas discharge device for the vehicle according to claim 1, wherein the extension pipe is sectioned into a first pipe, which is disposed adjacent to an inlet of the extension pipe, and a second pipe, which is disposed adjacent to an outlet of the extension pipe, wherein the first pipe has a bent part, which is provided in an end of the first pipe such that a diameter thereof is reduced to form the venturi passage, and the second pipe has a bent part in an end thereof, so that the first pipe and the second pipe are coupled to each other through the cover, such that the bent parts face each other, thus the bent parts, having the reduced diameters, serve as both the venturi passage and as a ring-shaped outside air discharge nozzle.

6. The exhaust gas discharge device for the vehicle according to claim 2, wherein the outside air discharge nozzle, which extends from the extension pipe into the venturi passage, is inclined in a direction in which the exhaust gas is discharged, and the outside air discharge nozzle comprises an inclined pipe, a diameter of which is reduced from the chamber to an air discharge end thereof.

7. The exhaust gas discharge device for the vehicle according to claim 2, wherein the outside air discharge nozzle and the backflow inlet port respectively comprise at least two outside air discharge nozzles and at least two backflow inlet ports.