EP3489477A1

EP3489477A1 - Two-sectioned back-pressured catalytic converter

Info

Publication number: EP3489477A1
Application number: EP17203064.5A
Authority: EP
Inventors: Hsin-Chang Chang
Original assignee: Jumbomaw Technology Co Ltd
Current assignee: Jumbomaw Technology Co Ltd
Priority date: 2017-11-22
Filing date: 2017-11-22
Publication date: 2019-05-29

Abstract

A two-sectioned back-pressured catalytic converter has a main body (10), a tail tube (40), and a honeycomb carrier (20). The honeycomb carrier (20) has a first section (21) relatively proximal to the intake opening and a second section (22) relatively proximal to the exhaust opening. The density of the holes of the first section (21) is higher than that of the second section (22). Therefore, waste gas has sufficient space for expansion when passing through the first section (21), and thus the pressure and the temperature are both lowered, solving problems of the back pressure and the backward pushing. The tail tube (40) forms a baffle in the main body (10). The waste gas will hit the baffle after passing the honeycomb carrier (20) and generate turbulence which can slow down the gas and make the gas fully react with the precious metal coating.

Description

1. Field of the Invention

The present invention relates to a catalytic converter of an exhaust pipe of an internal combustion engine, especially to a catalytic converter for vehicles.

2. Description of the Prior Arts

A catalytic converter is a device mounted in an exhaust pipe, adopts precious metal coating such as Platinum, Palladium, and Rhodium as catalyst, and reduces the toxic gas by catalytic mechanism. In order to fully convert the toxic gas, the prior arts generally use a honeycomb carrier to increase the surface area to complete the reaction.
Conventionally, a catalytic converter is combined with a main body and the honeycomb carrier. The main body is a hollow tube that may be in any shape, and the honeycomb carrier is mounted in the main body. The section of the honeycomb carrier is a high-density grid structure, and the aforementioned precious metal coating is deposited on the walls of the holes of the honeycomb carrier.
A density of the holes of the aforementioned honeycomb carrier is constant everywhere in each hole, and is generally from 1000 to 1200cpsi (Cells per Square Inch). Such a high-density structure has the following disadvantages.
First, the toxic gas is passing the honeycomb carrier slowly due to the high density of the holes while the engine is still discharging so that a back pressure may be generated and even push back the gas. Then the turbine blades will be broken because of the high temperature created by the increasing pressure which is the result of the slow flowing speed of the gas.
Second, the aforementioned back pressure will decrease the discharge efficiency and affect the power output of the engine at a low speed while the engine is still working at a high speed.
To overcome the shortcomings, the present invention provides a two-sectioned back-pressured catalytic converter to mitigate or obviate the aforementioned problems.
The main objective of the present invention is to provide a two-sectioned back-pressured catalytic converter that can reduce the pressure and the temperature of the carrier so that the turbine blades will not be broken due to the high temperature and the discharge efficiency will be improved.
The two-sectioned back-pressured catalytic converter comprises a main body, a tail tube, and a honeycomb carrier. The main body is hollow and has an intake opening and an exhaust opening. The tail tube is securely mounted in the exhaust opening of the main body and is mounted into the main body to form a baffle in the main body. The honeycomb carrier is mounted securely in the main body, and has a first section and a second section which are connected to each other. The first section is disposed proximal to the intake opening relative to the second section, and the second section is disposed proximal to the exhaust opening relative to the first section. The first section and the second section respectively have multiple holes. A density of the holes of the first section is higher than a density of the holes of the second section.
The honeycomb carrier has the first section and the second section of different densities, and the density of the holes of the first section is higher than the density of the holes of the second section. Thus, the waste gas has sufficient space for expansion with the pressure being reduced, thereby solving the problems of the back pressure and the pushing back gas and releasing the pressure accumulated in the first section. In addition, the baffle formed by the tail tube which is mounted into the main body creates turbulence when the toxic gas passing through the second section so that the toxic gas can stay in the second section longer to be fully converted.
Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

IN THE DRAWINGS

Fig. 1 is a side view of a first embodiment of a two-sectioned back-pressured catalytic converter in accordance with the present invention;
Fig. 2 is a side view in partial section of the two-sectioned back-pressured catalytic converter in Fig. 1;
Fig. 3 is a front view in partial section of a honeycomb carrier of the two-sectioned back-pressured catalytic converter in Fig. 1;
Fig. 4 is a side view in partial section of the two-sectioned back-pressured catalytic converter in Fig. 1, showing a flow of waste gas; and
Fig. 5 is a side view of a second embodiment of a two-sectioned back-pressured catalytic converter in accordance with the present invention.

With reference to Figs. 1 and 2, a two-sectioned back-pressured catalytic converter in accordance with the present invention comprises a main body 10, a honeycomb carrier 20, a connecting tube 30, and a tail tube 40.
The main body 10 is hollow and has an intake opening and an exhaust opening. In a preferred embodiment, the main body 10 further comprises an expanding section 11, a carrier section 12, and a tapered section 13 which are sequentially connected to one another. An opening of the expanding section 11 is said intake opening, and an inner diameter of the expanding section 11 progressively increases from the intake opening to the carrier section 12. An opening of the tapered section 13 is said exhaust opening, and an inner diameter of the tapered section 13 progressively decreases from the carrier section 12 to the exhaust opening. But an inner diameter of the main body 10 is not limited to the above mentioned, as the main body 10 can be implemented without the expanding section 11 and the tapered section 13, and the inner diameter of the main body 10 is of the same size from the intake opening to the exhaust opening.
The honeycomb carrier 20 is mounted securely on an inner wall of the main body 10. Specifically, the honeycomb carrier 20 is mounted securely on an inner wall of the carrier section 12 of the main body 10. The honeycomb carrier 20 comprises a first section 21 and a second section 22 which are connected to each other. The first section 21 is disposed proximal to the intake opening relative to the second section 22, and the second section 22 is disposed proximal to the exhaust opening relative to the first section 21. With reference to Figs. 2 and 3, the first section 21 and the second section 22 respectively have multiple holes 211, 221, and a density of the holes 211 of the first section 21 is higher than a density of the holes 221 of the second section 22.
In a preferred embodiment, the density of the holes 211 of the first section 21 is from 100 to 150cpsi, preferably 100cpsi. The density of the holes 221 of the second section 22 is from 60 to 100cpsi, preferably 60cpsi. But the densities of the holes 211, 221 are not limited to the abovementioned ranges and values.
In addition, in a preferred embodiment, a length of the first section 21 of the honeycomb carrier 20 is preferably, but not limited to, shorter than a length of the second section 22. Alternatively, the length of the first section 21 and the length of the second section 22 can also be equal or the length of the first section 21 is longer than the length of the second section 22.
In addition, a precious metal coating as the catalyst for reducing toxic gas is deposited on inner walls of the holes 211 of the first section 21 and also on inner walls of the holes 221 of the second section 22. In a preferred embodiment, the precious metal coating is made of, but not limited to, Platinum, Palladium, or Rhodium. Besides, a total surface area of the holes 211, 221 in the present invention is smaller than a total surface area of a conventional honeycomb carrier because of the density of the holes 211 of the first section 21 and the density of the holes 221 of the second section 22 are smaller than the density of the conventional honeycomb carrier. Thus, a concentration of the precious metal coating on the walls of the holes 211, 221 is higher in order to achieve the same catalytic efficiency of the conventional honeycomb carrier.
The connecting tube 30 is connected to an exhaust opening of an engine and communicates with the intake opening of the main body 10. Specifically, the connecting tube 30 is securely mounted into the expanding section 11, but it is not limited thereto, as the connecting tube 30 and the expanding section 11 can also be connected by butt-joint or by any other means. In addition, a mounting hole 31 is formed through a wall of the connecting tube 30 in order to be mounted with an oxygen sensor.
The tail tube 40 is mounted securely into the exhaust opening of the main body 10 and communicates with an exterior environment. Specifically, the tail tube 40 is securely mounted into the tapered section 13 of the main body 10. Because an inner diameter of the tapered section 13 is bigger than an outer diameter of the tail tube 40, the part of the tail tube 40 that is mounted into the tapered section 13 forms a baffle 42. In addition, a mounting hole 41 is formed through a wall of the tail tube 40 in order to be mounted with an oxygen sensor. Besides, with reference to Fig. 1, in a preferred embodiment, the tail tube 40 is preferably, but not limited to, a straight tube. In the second embodiment with reference to Fig. 5, the tail tube 40A can also be an upward curved tube.
For use, the present invention is mounted in the middle or the end part of the exhaust pipe. With reference to Fig. 4, when the engine is working, the toxic gas flows into the main body 10 from the connecting tube 30, and then enters the first section 21 to be converted for the first time after passing through the expanding section 11 of the main body 10. Because the density of the holes 211 is higher and the diameter of the holes 211 is smaller, the flowing speed of the gas is slow in the first section 21. After passing through the first section 21, the gas enters the second section 22, wherein the diameter of the holes is bigger to have the second conversion. This time the flowing speed of the gas is faster compared with the flowing speed of the first conversion that takes place in the first section 21. After the gas has passed through the second section 22, the gas that is relatively near the inner wall of the main body 10 flows along the inner wall of the tapered section 13 and end up hitting the baffle 42 which is formed by the part of the tail tube 40 that is mounted into the tapered section 13, and then turbulence is generated nearby the baffle 42. The turbulence will slow down the flow of the gas and then the gas will stay in the second section 22 longer to extend the time for the gas to be converted. After all this, the gas passes through the tail tube 40 and is discharged to the exterior environment. In addition, even if the main body 10 has no tapered section 13 and the inner diameter of the main body 10 is of a fixed size, the gas will still flow along the inner wall of the main body 10 and end up hitting the baffle 42 and generating the turbulence.
When the present invention is in use, the waste gas which has been converted and passed through the first section 21 enters the second section 22 which has the relatively bigger diameter of the holes. The bigger holes let the waste gas release the pressure and increase the flowing speed in order to achieve the purpose of reducing the back pressure, increasing the discharge efficiency in a low speed, and avoiding the turbine blades from being broken by the high temperature. In addition, the density of the holes of the present invention is lower than the density of the holes of the prior arts so that the present invention can reduce the pressure much more efficiently.
Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and features of the invention, the disclosure is illustrative only. Changes may be made in the details, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.

Claims

A two-sectioned back-pressured catalytic converter, and characterized in that the two-sectioned back-pressured catalytic converter comprises:
a main body (10) being hollow, and having
an intake opening; and

an exhaust opening;

a tail tube (40) securely mounted in the exhaust opening of the main body (10) and mounted into the main body (10) to form a baffle in the main body (10); and

a honeycomb carrier (20) mounted securely in the main body (10), and having
a first section (21) and a second section (22) which are connected to each other; the first section (21) disposed proximal to the intake opening relative to the second section (22), and the second section (22) disposed proximal to the exhaust opening relative to the first section (21); the first section (21) and the second section (22) respectively having multiple holes (211, 221), a density of the holes (211) of the first section (21) is higher than a density of the holes (221) of the second section (22).
The two-sectioned back-pressured catalytic converter as claimed in claim 1, wherein a length of the first section (21) is shorter than a length of the second section (22).
The two-sectioned back-pressured catalytic converter as claimed in claim 1 or 2, wherein the density of the holes (211) of the first section (21) is from 100 to 150cpsi.
The two-sectioned back-pressured catalytic converter as claimed in claim 3, wherein the density of the holes (211) of the first section (21) is 100cpsi.
The two-sectioned back-pressured catalytic converter as claimed in claim 1 or 2, wherein the density of the holes (221) of the second section (22) is from 60 to 100cpsi.
The two-sectioned back-pressured catalytic converter as claimed in claim 5, wherein the density of the holes (221) of the second section (22) is 60cpsi.
The two-sectioned back-pressured catalytic converter as claimed in claim 1 or 2, wherein the main body (10) has
a carrier section (12), the honeycomb carrier (20) mounted in the carrier section (12); and
a tapered section (13) connected to the carrier section (12), the exhaust opening formed on the tapered section (13), and the tail tube (40) mounted into the tapered section (13);
wherein an inner diameter of the tapered section (13) progressively decreases from the carrier section (12) to the exhaust opening.