EXHAUST GAS OUTLET MEANS FOR AN INTERNAL COMBUSTION ENGINE
United States Patent 3857458
Exhaust gas outlet means for an internal combustion engine comprising an exhaust pipe having an outlet end of a flattened cross-sectional configuration with a width smaller than diameter of unflattened portion and an open-ended fresh air suction pipe disposed with a clearance with the exhaust pipe and having a portion of reduced cross-sectional area around the outlet end of the exhaust pipe so as to define a suction throat in the vicinity of said outlet end.
US Patent References:
/1217615.html
Midowell - February 1917 - 1217615
Exhaust silencer
Sikes - May 1931 - 1804070
Air-cooled exhaust silencer
Smith - April 1957 - 2548563
Vertical muffler for internal combustion engine
Keene - December 1955 - 2725948
Exhaust gas purifying attachment
Villasenor et al. - April 1960 - 2932157
/1217615.html
Midowell - February 1917 - 1217615
Exhaust silencer
Sikes - May 1931 - 1804070
Air-cooled exhaust silencer
Smith - April 1957 - 2548563
Vertical muffler for internal combustion engine
Keene - December 1955 - 2725948
Exhaust gas purifying attachment
Villasenor et al. - April 1960 - 2932157
Inventors:
Ohtani, Toshio (Hiroshima-ken, JA)
Sato, Takahiro (Hiroshima-ken, JA)
Sumitomo, Fukishi (Hiroshima-ken, JA)
Sato, Takahiro (Hiroshima-ken, JA)
Sumitomo, Fukishi (Hiroshima-ken, JA)
Application Number:
05/394817
Publication Date:
12/31/1974
Filing Date:
09/06/1973
View Patent Images:
Export Citation:
Assignee:
Toyo Kogyo Co., Ltd. (Hiroshima-ken, JA)
Primary Class:
Other Classes:
60/319
International Classes:
F01N1/14; F01N3/05; F01N7/08; F01N1/14; F01N3/04
Field of Search:
181/43,36B 60/316,317,319
US Patent References:
Primary Examiner:
Wilkinson, Richard B.
Assistant Examiner:
Miska, Vit W.
Attorney, Agent or Firm:
Fleit & Jacobson
Claims:
We claim
1. Exhaust gas outlet means for an internal combustion engine, the outlet means comprising: an elongated exhaust pipe having a predetermined diameter through a portion of its length, and an outlet end whose cross-sectional configuration is gradually flattened in a first plane into a converging nozzle, and whose cross-sectional configuration is V-shaped in a second plane transverse to said first plane to define a diverging nozzle, the cross-sectional area of said outlet end being at least equal to that of the exhaust pipe in the said portion of its length having a predetermined diameter, and an open-ended fresh air suction pipe disposed around and with a clearance from the exhaust pipe and having a portion of reduced cross-sectional area around the outlet end of the exhaust pipe so as to define a suction throat at said outlet end.
2. Exhaust gas outlet means in accordance with claim 1 which said suction pipe has a flattened cross-sectional configuration at said portion of reduced cross-sectional area.
3. Exhaust gas outlet means in accordance with claim 1 which said portion of reduced cross-sectional area is formed at the intermediate portion of the suction pipe.
4. Exhaust gas outlet means in accordance with claim 1 in which said exhaust pipe is provided with a silencer and said suction pipe is extended to encircle said silencer with a clearance thereto.
1. Exhaust gas outlet means for an internal combustion engine, the outlet means comprising: an elongated exhaust pipe having a predetermined diameter through a portion of its length, and an outlet end whose cross-sectional configuration is gradually flattened in a first plane into a converging nozzle, and whose cross-sectional configuration is V-shaped in a second plane transverse to said first plane to define a diverging nozzle, the cross-sectional area of said outlet end being at least equal to that of the exhaust pipe in the said portion of its length having a predetermined diameter, and an open-ended fresh air suction pipe disposed around and with a clearance from the exhaust pipe and having a portion of reduced cross-sectional area around the outlet end of the exhaust pipe so as to define a suction throat at said outlet end.
2. Exhaust gas outlet means in accordance with claim 1 which said suction pipe has a flattened cross-sectional configuration at said portion of reduced cross-sectional area.
3. Exhaust gas outlet means in accordance with claim 1 which said portion of reduced cross-sectional area is formed at the intermediate portion of the suction pipe.
4. Exhaust gas outlet means in accordance with claim 1 in which said exhaust pipe is provided with a silencer and said suction pipe is extended to encircle said silencer with a clearance thereto.
Description:
The present invention relates to an engine exhaust system and more particularly to exhaust gas outlet means for an automobile engine exhaust system having exhaust gas cleaning means.
Recently, in an automobile engine, it has been necessitated, in order to reduce air polluting constituents in the exhaust gas, to provide exhaust gas cleaning means such as a thermal reactor or a catalytic reactor in the exhaust system of the engine. However, it has been noted that such a type of exhaust gas cleaning means cause an increase in temperature of the exhaust gas at the outlet end of the exhaust pipe and in some cases it has been found that the exhaust gas temperature is as high as 600°C. Particularly, when an engine is operating at an idling speed with a choke device in operation, the reaction in the exhaust gas cleaning means is highly activated and the exhaust gas temperature is remarkably increased. The increased temperature of the exhaust gas causes various troubles such as a burn hazard of a person, a fire hazard and adverse effects on the road surface.
Hithertofore, in addition to a conventional structure in which the exhaust pipe has a merely straightly cut outlet end, there has been proposed to provide an openended fresh air suction pipe having a reduced inner diameter portion which is disposed with a clearance around the outlet end of the exhaust pipe so that a throat portion is formed between the outlet end of the exhaust pipe and the reduced diameter portion of the suction pipe. An example of such an arrangement is disclosed by Japanese Patent Publication No. 19042/69. This arrangement is found as being effective to a certain degree to reduce the temperature of the exhaust gas, however, it cannot reduce the temperature to a satisfactory level. Further, it has also been proposed to open the outlet end of the exhaust pipe downwardly so that the exhaust gas is discharged toward the road surface. This arrangement, however, does not basically solve the problem.
Therefore, the present invention has an object to eliminate the aforementioned problems of prior art.
Another object of the present inventon is to provide exhaust gas outlet means for an automobile engine in which temperature of exhaust gas can be decreased to a satisfactory level.
A further object of the present invention is to provide simple and effective means for decreasing engine exhaust gas temperature.
According to the present invention, the above objects can be achieved by exhaust gas outlet means comprising an engine exhaust pipe having a substantially flat outlet end with a width smaller than diameter of unflattened portion of the exhaust pipe and an open-ended fresh air suction pipe disposed with a clearance around the outlet end of the exhaust pipe, said suction pipe having a portion of reduced cross-sectional area adjacent to the exhaust pipe outlet end so that a suction throat is defined between the exhaust pipe and the suction pipe for drawing fresh air from one end of the suction pipe and discharging it with exhaust gas at the other end of the suction pipe.
In an engine having a silencer provided in the exhaust system, the fresh air suction pipe may be extended so as to enclose the silencer by the extended portion of the suction pipe. This arrangement is effective to reduce exhaust noise level as well as the exhaust gas temperature.
The above and other objects and features of the present invention will become apparent from the following descriptions of preferred embodiments taking reference to the accompanying drawings, in which:
FIG. 1 is side elevational view of exhaust gas outlet means in accordance with one embodiment of the present invention;
FIG. 2 is a top plan view of the exhaust gas outlet means shown in FIG. 1;
FIG. 3 is an end view of the exhaust gas outlet means shown in FIGS. 1 and 2;
FIG. 4 is a vertical sectional view of exhaust gas outlet means in accordance with another embodiment of the present invention;
FIG. 5 is a horizontal sectional view of the exhaust gas outlet means shown in FIG. 4;
FIG. 6 is an end view of the exhaust gas outlet means shown in FIGS. 4 and 5; and
FIG. 7 is a diagram showing exhaust gas temperature changes in various types of exhaust gas outlet means.
Referring now to the drawings, particularly to FIGS. 1 through 3, there is shown an engine exhaust system including an exhaust pipe 1. As shown in the drawings, the exhaust pipe 1 is flattened in V-shape at its outlet end 2. That is, the outlet end 2 tapers from the circular portion of the exhaust pipe 1 into a converging nozzle in one plane and into a diverging nozzle in a transverse plane. The width of the flattened outlet end 2 of the exhaust pipe 1 is substantially smaller than the diameter of the unflattened cylindrical portion thereof as clearly shown in FIG. 3. The cross-sectional area of the outlet end 2 is the same as or larger than that of the remaining portion of the exhaust pipe 1. Around the outlet end 2 of the exhaust pipe 1, there is supported an open ended fresh air suction pipe 3 which is supported with a suitable clearance a with the exhaust pipe 1 by means of support members 4. The suction pipe 3 also has a flattened cross-section as shown in FIG. 3 and reduced in cross-sectional area at the intermediate portion thereof. Thus, a throat portion of reduced cross-sectional area is defined adjacent to the outlet end 2 of the exhaust pipe 1. In operation of the engine, therefore, as the exhaust gas is discharged from the outlet end 2 of the exhaust pipe 1, a suction pressure is produced in the suction pipe 3 around the area of reduced cross-section, so that fresh air is drawn into the pipe 3 from the left end as in FIGS. 1 and 2, passed therethrough and discharged from the right end together with the exhaust gas from the exhaust pipe 1. Since the outlet end 2 of the exhaust pipe 1 and the suction pipe 3 have flattened cross-sectional shape as described before, the fresh air drawn into the pipe 3 is sufficiently mixed with the exhaust gas from the pipe 1, so that the temperature of the exhaust gas is decreased to a satisfactory level.
FIGS. 4 through 6 show another embodiment of the present invention. In the drawings, the exhaust gas outlet means includes an exhaust pipe 11 which has a flattened outlet end 12. The exhaust pipe 11 is supported under a vehicle floor by means of a support member 14. In the exhaust pipe 11, there is disposed a silencer 15 which may be of a conventional type. Around the end portion of the exhaust pipe 11 and the silencer 15, there is disposed a fresh air suction pipe 16 which is supported by means of support members 17 on the exhaust pipe 11 with a suitable clearance therewith. Further, the suction pipe 16 is also supported by support members 18 on the vehicle floor 13. The suction pipe 16 encircles the silencer 15 and flattened around the outlet end 12 of the exhaust pipe 11 as shown in FIG. 6. The suction pipe 16 has an open left end which defines an air intake port 19 around the exhaust pipe 11. Further, the pipe 16 is provided with a portion 16a of reduced cross-sectional area to define a throat portion around the outlet end 12 of the exhaust pipe 11.
In this arrangement, as the exhaust gas is discharged from the exhaust pipe 11, fresh air is introduced from the intake port 19 into the suction pipe 16, passes around the silencer 15 and the exhaust pipe 11 and is discharged from the suction pipe 16 together with the exhaust gas. This arrangement is effective not only to reduce the exhaust temperature but also to decrease noise level.
FIG. 7 shows exhaust gas temperature in various types of exhaust gas outlet means. In the drawing, the curves A through C show temperatures in conventional arrangements, and the curve D shows that in the arrangement shown in FIGS. 1 through 3 of the present invention. It should be noted that the present invention is very effective to decrease the exhaust gas temperature as compared with conventional arrangement.
Although the invention has been shown and described with reference to preferred embodiments, it should be noted that the invention shall in no way limited to the details the illustrated structures but changes and modifications can be made without departing from the scope of the appended claims.
Recently, in an automobile engine, it has been necessitated, in order to reduce air polluting constituents in the exhaust gas, to provide exhaust gas cleaning means such as a thermal reactor or a catalytic reactor in the exhaust system of the engine. However, it has been noted that such a type of exhaust gas cleaning means cause an increase in temperature of the exhaust gas at the outlet end of the exhaust pipe and in some cases it has been found that the exhaust gas temperature is as high as 600°C. Particularly, when an engine is operating at an idling speed with a choke device in operation, the reaction in the exhaust gas cleaning means is highly activated and the exhaust gas temperature is remarkably increased. The increased temperature of the exhaust gas causes various troubles such as a burn hazard of a person, a fire hazard and adverse effects on the road surface.
Hithertofore, in addition to a conventional structure in which the exhaust pipe has a merely straightly cut outlet end, there has been proposed to provide an openended fresh air suction pipe having a reduced inner diameter portion which is disposed with a clearance around the outlet end of the exhaust pipe so that a throat portion is formed between the outlet end of the exhaust pipe and the reduced diameter portion of the suction pipe. An example of such an arrangement is disclosed by Japanese Patent Publication No. 19042/69. This arrangement is found as being effective to a certain degree to reduce the temperature of the exhaust gas, however, it cannot reduce the temperature to a satisfactory level. Further, it has also been proposed to open the outlet end of the exhaust pipe downwardly so that the exhaust gas is discharged toward the road surface. This arrangement, however, does not basically solve the problem.
Therefore, the present invention has an object to eliminate the aforementioned problems of prior art.
Another object of the present inventon is to provide exhaust gas outlet means for an automobile engine in which temperature of exhaust gas can be decreased to a satisfactory level.
A further object of the present invention is to provide simple and effective means for decreasing engine exhaust gas temperature.
According to the present invention, the above objects can be achieved by exhaust gas outlet means comprising an engine exhaust pipe having a substantially flat outlet end with a width smaller than diameter of unflattened portion of the exhaust pipe and an open-ended fresh air suction pipe disposed with a clearance around the outlet end of the exhaust pipe, said suction pipe having a portion of reduced cross-sectional area adjacent to the exhaust pipe outlet end so that a suction throat is defined between the exhaust pipe and the suction pipe for drawing fresh air from one end of the suction pipe and discharging it with exhaust gas at the other end of the suction pipe.
In an engine having a silencer provided in the exhaust system, the fresh air suction pipe may be extended so as to enclose the silencer by the extended portion of the suction pipe. This arrangement is effective to reduce exhaust noise level as well as the exhaust gas temperature.
The above and other objects and features of the present invention will become apparent from the following descriptions of preferred embodiments taking reference to the accompanying drawings, in which:
FIG. 1 is side elevational view of exhaust gas outlet means in accordance with one embodiment of the present invention;
FIG. 2 is a top plan view of the exhaust gas outlet means shown in FIG. 1;
FIG. 3 is an end view of the exhaust gas outlet means shown in FIGS. 1 and 2;
FIG. 4 is a vertical sectional view of exhaust gas outlet means in accordance with another embodiment of the present invention;
FIG. 5 is a horizontal sectional view of the exhaust gas outlet means shown in FIG. 4;
FIG. 6 is an end view of the exhaust gas outlet means shown in FIGS. 4 and 5; and
FIG. 7 is a diagram showing exhaust gas temperature changes in various types of exhaust gas outlet means.
Referring now to the drawings, particularly to FIGS. 1 through 3, there is shown an engine exhaust system including an exhaust pipe 1. As shown in the drawings, the exhaust pipe 1 is flattened in V-shape at its outlet end 2. That is, the outlet end 2 tapers from the circular portion of the exhaust pipe 1 into a converging nozzle in one plane and into a diverging nozzle in a transverse plane. The width of the flattened outlet end 2 of the exhaust pipe 1 is substantially smaller than the diameter of the unflattened cylindrical portion thereof as clearly shown in FIG. 3. The cross-sectional area of the outlet end 2 is the same as or larger than that of the remaining portion of the exhaust pipe 1. Around the outlet end 2 of the exhaust pipe 1, there is supported an open ended fresh air suction pipe 3 which is supported with a suitable clearance a with the exhaust pipe 1 by means of support members 4. The suction pipe 3 also has a flattened cross-section as shown in FIG. 3 and reduced in cross-sectional area at the intermediate portion thereof. Thus, a throat portion of reduced cross-sectional area is defined adjacent to the outlet end 2 of the exhaust pipe 1. In operation of the engine, therefore, as the exhaust gas is discharged from the outlet end 2 of the exhaust pipe 1, a suction pressure is produced in the suction pipe 3 around the area of reduced cross-section, so that fresh air is drawn into the pipe 3 from the left end as in FIGS. 1 and 2, passed therethrough and discharged from the right end together with the exhaust gas from the exhaust pipe 1. Since the outlet end 2 of the exhaust pipe 1 and the suction pipe 3 have flattened cross-sectional shape as described before, the fresh air drawn into the pipe 3 is sufficiently mixed with the exhaust gas from the pipe 1, so that the temperature of the exhaust gas is decreased to a satisfactory level.
FIGS. 4 through 6 show another embodiment of the present invention. In the drawings, the exhaust gas outlet means includes an exhaust pipe 11 which has a flattened outlet end 12. The exhaust pipe 11 is supported under a vehicle floor by means of a support member 14. In the exhaust pipe 11, there is disposed a silencer 15 which may be of a conventional type. Around the end portion of the exhaust pipe 11 and the silencer 15, there is disposed a fresh air suction pipe 16 which is supported by means of support members 17 on the exhaust pipe 11 with a suitable clearance therewith. Further, the suction pipe 16 is also supported by support members 18 on the vehicle floor 13. The suction pipe 16 encircles the silencer 15 and flattened around the outlet end 12 of the exhaust pipe 11 as shown in FIG. 6. The suction pipe 16 has an open left end which defines an air intake port 19 around the exhaust pipe 11. Further, the pipe 16 is provided with a portion 16a of reduced cross-sectional area to define a throat portion around the outlet end 12 of the exhaust pipe 11.
In this arrangement, as the exhaust gas is discharged from the exhaust pipe 11, fresh air is introduced from the intake port 19 into the suction pipe 16, passes around the silencer 15 and the exhaust pipe 11 and is discharged from the suction pipe 16 together with the exhaust gas. This arrangement is effective not only to reduce the exhaust temperature but also to decrease noise level.
FIG. 7 shows exhaust gas temperature in various types of exhaust gas outlet means. In the drawing, the curves A through C show temperatures in conventional arrangements, and the curve D shows that in the arrangement shown in FIGS. 1 through 3 of the present invention. It should be noted that the present invention is very effective to decrease the exhaust gas temperature as compared with conventional arrangement.
Although the invention has been shown and described with reference to preferred embodiments, it should be noted that the invention shall in no way limited to the details the illustrated structures but changes and modifications can be made without departing from the scope of the appended claims.