JP2007198322A - Exhaust structure of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust structure of an internal combustion engine capable of suppressing the pollution of a silencer by unburned fuel by easily removing the unburned fuel from exhaust gases before the exhaust gases containing the unburned fuel flows from an exhaust manifold to the silencer through an exhaust pipe. <P>SOLUTION: The silencer 4 is connected to the exhaust manifold 3 of the internal combustion engine 1 through the exhaust pipe 10 for discharging the exhaust gases. The exhaust pipe is formed in a generally L-shape when viewed from the front. A discharge means 13 for discharging the unburned fuel in the bent part 10c of the exhaust pipe 10 to the outside is installed at the lowermost part of the bent part 10c of the exhaust pipe 10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an exhaust structure of an internal combustion engine in which a silencer is connected to an exhaust manifold of the internal combustion engine via an exhaust pipe to discharge exhaust gas.

Conventionally, an internal combustion engine is provided with various catalysts in an exhaust pipe connected to its exhaust port, and the catalyst removes unburned fuel and combustion products of the fuel contained in the exhaust gas so that the exhaust gas is discharged to the outside. Some have an exhaust structure that purifies before exhaust (see, for example, Patent Document 1), but exhaust gas is exhausted through an exhaust pipe without processing unburned fuel or fuel combustion products contained in the exhaust gas. Many of them have an exhaust structure for discharging. In the latter case, for example, as shown in FIG. 6, an exhaust manifold 23 and a silencer 24 are connected to the internal combustion engine 21 via an exhaust pipe 25 made of a cylindrical body having a constant inner diameter, and the exhaust gas flowing out from the exhaust port. Is exhausted from the exhaust manifold 23 through the exhaust pipe 25 to the silencer 24 and then discharged to the outside.
Japanese Patent Laid-Open No. 5-71433

  However, in the conventional exhaust structure of an internal combustion engine as shown in FIG. 6, when unburned fuel is generated by combustion during low load operation, the unburned fuel is contained in the exhaust gas, and the exhaust manifold, exhaust pipe, silencer Will be discharged to the outside in order. For this reason, unburned fuel in the exhaust gas adheres to each part in the silencer, causing the inside of the silencer to become dirty, and the silencer's silencing function tends to be impaired. Furthermore, if the inside of the silencer is contaminated with unburned fuel, the unburned fuel may ignite as the silencer rises in temperature, which may generate sparks.

  Therefore, in the present invention, before the exhaust gas containing unburned fuel reaches the silencer from the exhaust manifold through the exhaust pipe, the unburned fuel is easily removed from the exhaust gas and the dirt of the silencer caused by the unburned fuel is suppressed. It is an object of the present invention to provide an exhaust structure for an internal combustion engine that can achieve the above.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  That is, in claim 1, in the exhaust structure of the internal combustion engine that connects the silencer to the exhaust manifold of the internal combustion engine via the exhaust pipe and exhausts the exhaust gas, the exhaust pipe is configured in a substantially L shape in front view, Discharge means for discharging unburned fuel in the bent portion to the outside is provided at the lowermost portion of the bent portion of the exhaust pipe.

  According to a second aspect of the present invention, capturing means for capturing unburned fuel in the exhaust gas is disposed at the bent portion.

  According to a third aspect of the present invention, heating means for combusting unburned fuel in the bent portion is disposed in the bent portion.

  According to a fourth aspect of the present invention, a capturing means for capturing unburned fuel in the exhaust gas and a heating means for burning the unburned fuel in the bent portion are arranged at the bent portion.

  According to a fifth aspect of the present invention, an opening is formed in the bent portion, and a lid that covers the opening in an openable and closable manner is provided.

  As effects of the present invention, the following effects can be obtained.

  In claim 1, since exhaust gas from the exhaust manifold side collides with the bent portion in the exhaust pipe and flows to the silencer side, unburned fuel contained in the exhaust gas is attached to the bent portion. It can be separated from the exhaust gas and collected at the bottom. Then, the unburned fuel collected at the lowermost portion by the discharge means can be discharged and extracted from the bent portion to the outside. This makes it possible to easily remove unburned fuel from the exhaust gas in the exhaust pipe and prevent the silencer from reaching the silencer, thereby suppressing the contamination by unburned fuel inside the silencer and extending the life of the silencer. Can do.

  In claim 2, when exhaust gas from the exhaust manifold flows into the bent portion through the exhaust pipe, unburned fuel can be captured by the capture means and separated from the exhaust gas, and efficiently collected at the bent portion. Can do.

  According to the third aspect of the present invention, the unburned fuel adhering to the bent portion or the unburned fuel collected at the lowermost portion thereof can be burned and burned out from the bent portion by the heating means. Further, since unburned fuel can be removed from the bent portion by heating by the heating means, maintenance is facilitated.

  According to the fourth aspect of the present invention, when the exhaust gas from the exhaust manifold flows into the bent portion, the unburned fuel can be captured by the capturing means and separated from the exhaust gas, and can be efficiently collected at the bent portion. Furthermore, the unburned fuel adhering to the bent portion by the heating means or the unburned fuel collected at the lowermost portion thereof can be burned and burned out from the bent portion.

  According to the fifth aspect of the present invention, by removing the lid from the bent portion, maintenance of the bent portion itself, the capturing means disposed in the inside thereof, and the heating means can be easily performed. Further, the capturing means and the heating means can be added later to the bent portion, and the capturing means or the heating means arranged in the bent portion can be easily changed from one to the other.

  Next, embodiments of the invention will be described.

  1 is a front view showing an overall configuration of an exhaust structure of an internal combustion engine according to an embodiment of the present invention, FIG. 2 is a side sectional view of the exhaust pipe, and FIG. 3 is an exhaust pipe in which a filter net is arranged at a bent portion. 4 is a side sectional view of an exhaust pipe in which a heater element is disposed at a bent portion, FIG. 5 is a side sectional view of the exhaust pipe in which a filter net and a heater element are disposed at the bent portion, and FIG. It is the figure which showed the whole structure of the exhaust structure of an internal combustion engine.

  As shown in FIG. 1, in an internal combustion engine 1, an exhaust manifold 3 is attached to one side of a cylinder head 2 disposed on a cylinder block, and the exhaust manifold 3 and the combustion chamber of the cylinder block are communicated with each other via an exhaust port. ing. A silencer 4 is also connected to the exhaust manifold 3 via an exhaust pipe 10, and the silencer 4 and the exhaust manifold 3 are communicated with each other. Thus, the exhaust structure of the internal combustion engine 1 is configured so that the exhaust gas flowing out from the exhaust port flows into the silencer 4 from the exhaust manifold 3 through the exhaust pipe 10 and then is discharged to the outside.

  In the exhaust structure of the present invention in the internal combustion engine 1, as shown in FIG. 2, the exhaust pipe 10 that connects the exhaust manifold 3 and the silencer 4 has a horizontal portion 10 a that extends substantially horizontally on the exhaust manifold 3 side. And a vertical portion 10b extending in the vertical direction on the silencer 4 side, and a bent portion 10c positioned between the horizontal portion 10a and the vertical portion 10b. An exhaust passage is provided. A flange is provided at the other end of the horizontal portion 10a and is fixed to the exhaust manifold 3 by a bolt or the like, and a flange is also provided at the other end of the vertical portion 10b and is fixed to the silencer 4 above the bent portion 10c by a bolt or the like. ing. In this way, the exhaust pipe 10 can be easily attached to and detached from the exhaust manifold 3 and the silencer 4 so that the replacement work is easy.

  The bent portion 10c has an opening 10e on the outer peripheral side thereof, and the opening 10e is closed by a lid 10d. Specifically, the outer side of the bent portion 10c, in other words, an exhaust manifold. 3, a lid 10 d is detachably attached so as to cover an opening 10 e provided on the side far from 3. The lid body 10d is inclined upward from the horizontal part 10a side to the vertical part 10b side, and is arranged so as to be positioned on an extension line of the horizontal part 10a and the vertical part 10b. A concave portion 10f is provided on the inner side of the lid body 10d, and the lowermost portion thereof is positioned below the bottom portion of the horizontal portion 10a to form the lowermost portion 10g of the bent portion 10c. It is also possible to form the bent portion 10c by integrally forming the recess without providing the opening 10e and the lid 10d.

  A drain hole 10h is provided in the lowermost part 10g of the bent part 10c, that is, the lowermost part of the lid 10d, and the drain serves as a discharge means for discharging unburned fuel in the bent part 10c to the outside with respect to the drain hole 10h. A plug 13 or the like is screwed and attached so as to be opened and closed. By removing the drain plug 13 that closes the drain hole 10h in this configuration, the inside of the bent portion 10c and the outside can communicate with each other through the drain hole 10h. The exhaust pipe 10 can be easily formed by hydroforming or bending, and can be manufactured at low cost.

  In such a configuration, when exhaust gas flows out from the exhaust port of the cylinder head 2 to the exhaust manifold 3, the exhaust gas passes through the exhaust inlet 10j from the exhaust manifold 3 through the exhaust inlet 10j as indicated by the two-dot chain line shown in FIG. 10 flows into the horizontal portion 10a and flows in the horizontal direction toward the bent portion 10c through the exhaust passage. When reaching the bent portion 10c, the exhaust gas collides with the concave portion 10f of the lid 10d because the lid 10d is positioned in the exhaust flow direction, whereby the exhaust flow direction is switched to the vertical direction and the vertical portion 10b. The exhaust gas flows through the exhaust passage of the vertical portion 10b to the silencer 4, and is then discharged to the outside. The bent portion 10c has a concave portion 10f, and the volume of the bent portion 10c is larger than that of the horizontal portion 10a. Therefore, noise can be reduced and the temperature can be reduced due to the volume expansion of the exhaust gas.

  In the exhaust process in the exhaust pipe 10, when exhaust gas flows into the bent portion 10c and collides with the concave portion 10f of the lid 10d, unburned fuel contained in the exhaust gas adheres to the concave portion 10f due to the impact. Separated from the exhaust gas. That is, the amount of unburned fuel is removed from the exhaust gas. The unburned fuel separated from the exhaust gas flows down the lid 10d along the inclination of the recess 10f and is collected in the lowermost part 10g of the bent part 10c. The unburned fuel collected in the lowermost portion 10g is discharged to the outside through the drain hole 10h by removing the drain plug 13 that closes the drain hole 10h, and can be removed from the bent portion 10c. Yes.

  As described above, in the exhaust structure of the internal combustion engine in which the silencer 4 is connected to the exhaust manifold 3 of the internal combustion engine 1 via the exhaust pipe 10 and exhaust gas is discharged, the exhaust pipe is configured in a substantially L shape in front view. Since the drain plug 13 serving as a discharge means for discharging unburned fuel in the bent portion 10c to the outside is provided at the lowermost portion of the bent portion 10c of the exhaust pipe 10, the exhaust gas from the exhaust manifold 3 side in the exhaust pipe 10 is provided. Since the gas flows into the silencer 4 after colliding with the bent portion 10c, unburned fuel contained in the exhaust gas is separated from the exhaust gas by being attached to the bent portion 10c and collected in the lowermost portion 10g. Can do. Then, the unburned fuel collected in the lowermost portion 10g can be discharged out of the bent portion 10c and extracted by removing the drain plug 13 by the discharging means. As a result, unburned fuel can be easily removed from the exhaust gas through the exhaust pipe 10 so that it does not reach the silencer 4. Therefore, contamination by unburned fuel inside the silencer 4 is suppressed, and the silencer 4 Life can be extended.

  Further, the bent portion 10c of the exhaust pipe 10 is provided with a capturing means for capturing unburned fuel in the exhaust gas so that the unburned fuel can be separated and removed from the exhaust gas more efficiently. There is also. The capture means is constituted by a filter net 15, for example, as shown in FIG. The filter net 15 is provided over the entire recess 10f provided inside the lid 10d, and is arranged so as to collide with the exhaust gas flowing from the exhaust manifold 3 side through the horizontal portion 10a.

  As described above, in the exhaust structure of the internal combustion engine 1, the exhaust pipe 10 exhausts the exhaust pipe 10 by arranging the filter net 15 serving as a capturing means for capturing unburned fuel in the exhaust gas at the bent portion 10 c of the exhaust pipe 10. When the exhaust gas from the manifold 3 side flows into the bent portion 10c, the unburned fuel can be captured by the filter net 15 and separated from the exhaust gas, and can be efficiently collected at the bent portion 10c. At this time, the exhaust noise is absorbed by the filter net 15 so that the noise can be reduced.

  Alternatively, the bent portion 10c of the exhaust pipe 10 has unfolded fuel in the bent portion 10c so that unburned fuel collected in the lowermost portion 10g and unburned fuel remaining attached can be removed from the bent portion 10c. A heating means for burning the fuel may be provided. The heating means is composed of a heater element 17, for example, as shown in FIG. The heater element 17 is provided so as to be able to be energized by operating means (not shown) over the entire recess 10f provided inside the lid 10d. The heater element 17 causes unburned fuel collected in the lowermost portion 10g or bent when the heater element 17 is energized. The unburned fuel remaining attached to the part 10c can be burned.

  As described above, in the exhaust structure of the internal combustion engine 1, the heater element 17 serving as a heating unit for burning the unburned fuel in the bent portion 10c is disposed in the bent portion 10c of the exhaust pipe 10. Thus, the unburned fuel adhering to the bent portion 10c and the unburned fuel collected in the lowermost portion 10g can be burned and burned out from the bent portion 10c. Further, since unburned fuel can be removed from the bent portion 10c by heating by the heating means, that is, by energizing the heater element 17, maintenance is facilitated.

  Furthermore, both the capturing means and the heating means may be provided in the bent portion 10c. Similarly, when the trapping means is the filter net 15 and the heating means is the heater element 17, for example, as shown in FIG. 5, the filter net 15 and the heater element 17 are provided inside the lid 10d. In the same manner as described above, the filter net 15 is arranged so as to be able to collide with the exhaust gas flowing from the exhaust manifold 3 side through the horizontal portion 10a, and the heater element 17 is energized. It arrange | positions so that the unburned fuel adhering to the bending part 10c and the unburned fuel collected by the lowermost part 10g can be burned.

  Thus, in the exhaust structure of the internal combustion engine 1, the exhaust pipe 10 is connected to the exhaust manifold 10 by disposing the filter net 15 as the capture means and the heater element 17 as the heating means at the bent portion 10 c of the exhaust pipe 10. When exhaust gas from the third side flows into the bent portion 10c, unburned fuel can be captured by the filter net 15 and separated from the exhaust gas, and can be efficiently collected at the bent portion 10c. Furthermore, the unburned fuel adhering to the bent portion 10c by the heater element 17 and the unburned fuel collected in the lowermost portion 10g can be burned and burned out from the bent portion 10c.

  Further, in the exhaust structure of the internal combustion engine 1, since the opening 10e is formed in the bent portion 10c of the exhaust pipe 10 as described above, and the lid 10d that covers the opening 10e so as to be opened and closed is provided, the bent portion 10c is provided. By removing the lid body 10d from the casing, maintenance of the bent portion 10c itself and the filter net 15 as the capturing means disposed therein and the heater element 17 as the heating means can be easily performed. Furthermore, the filter net 15 and the heater element 17 can be added later to the bent portion 10c, and the filter net 15 or the heater element 17 arranged in the bent portion 10c can be easily changed from one to the other.

1 is a front view showing an overall configuration of an exhaust structure of an internal combustion engine according to an embodiment of the present invention. Side surface sectional drawing of an exhaust pipe. Side surface sectional drawing of the exhaust pipe which has arrange | positioned the filter net in the bending part. Side surface sectional drawing of the exhaust pipe which has arrange | positioned the heater element in the bending part. Side surface sectional drawing of the exhaust pipe which has arrange | positioned the filter net | network and the heater element in the bending part. The figure which showed the whole structure of the exhaust structure of the conventional internal combustion engine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 3 Exhaust manifold 4 Silencer 10 Exhaust pipe 10c Bending part 10d Cover body 10e Opening part 13 Drain plug (discharge means)
15 Filter net (capture means)
17 Heater element (heating means)

Claims (5)

  In an exhaust structure of an internal combustion engine in which a silencer is connected to an exhaust manifold of the internal combustion engine via an exhaust pipe and exhaust gas is exhausted, the exhaust pipe is configured in a substantially L shape when viewed from the front, and the lowermost part of the bent portion of the exhaust pipe An exhaust structure for an internal combustion engine, characterized in that exhaust means for discharging unburned fuel in the bent portion to the outside is provided.   2. The exhaust structure for an internal combustion engine according to claim 1, wherein a capture means for capturing unburned fuel in the exhaust gas is disposed at the bent portion.   2. An exhaust structure for an internal combustion engine according to claim 1, wherein heating means for burning unburned fuel in the bent portion is disposed in the bent portion.   2. The internal combustion engine according to claim 1, wherein a capture means for capturing unburned fuel in the exhaust gas and a heating means for burning the unburned fuel in the bent portion are arranged in the bent portion. Exhaust structure. The exhaust structure for an internal combustion engine according to any one of claims 1 to 4, further comprising a lid that forms an opening in the bent portion and covers the opening so as to be openable and closable.

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