Exhaust pipe structure for internal combustion engine

Abstract

To prevent condensed water from being accumulated in an exhaust pipe.SOLUTION: An exhaust pipe structure 10 for an internal combustion engine includes an exhaust pipe 20 which is arranged under a floor panel of a vehicle 1 while extending along a horizontal direction in a vehicle side face view for making exhaust gas flow to the rear side of the vehicle. The exhaust pipe 20 is internally provided with swollen parts 100a-100c swollen upward from a bottom part 53. Condensed water accumulated in the exhaust pipe 20 contacts the swollen parts 100a-100c to be able to easily cause the melting of the frozen condensed water or the evaporation of the condensed water.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an exhaust pipe structure of an internal combustion engine.

Background Art

[0002] Generally, a vehicle equipped with an engine is provided with an exhaust pipe that allows exhaust gas to flow rearward of the vehicle. When the water vapor contained in the exhaust gas flows through the exhaust pipe, it may accumulate in the exhaust pipe as condensed water due to temperature changes or the like.

[0003] Patent Document 1 discloses an exhaust pipe structure in which recesses that are concave downward are provided before and after a horizontal portion of the exhaust pipe where condensed water tends to accumulate. According to such an exhaust pipe structure, when the vehicle travels on an inclined road, condensed water is accumulated in the recesses, and the cross-sectional area of the flow path decreases, so that a negative pressure due to the exhaust gas is generated in the recesses, and it is disclosed that the condensed water can be drained all at once.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the exhaust pipe structure of Patent Document 1 is considered only in a limited scenario where the vehicle travels on an inclined road. Also, when the flow rate of the exhaust gas is small, such as during short-time driving, the condensed water in the exhaust pipe is not completely drained, and the remaining condensed water may freeze in the exhaust pipe when the air temperature is low. If the condensed water freezes in the exhaust pipe, the exhaust pipe may be blocked.

[0006] The present invention has been made in view of the above-described problems, and an object thereof is to prevent condensed water from accumulating in the exhaust pipe.

Means for Solving the Problems

[0007] The present invention relates to an exhaust pipe structure of an internal combustion engine that is disposed below a floor panel of a vehicle, extends along a horizontal direction in a side view of the vehicle, and allows exhaust gas to flow rearward of the vehicle, wherein the exhaust pipe is provided with a bulging portion that bulges upward from a bottom inside.

Advantages of the Invention

[0008] According to the present invention, condensed water can be prevented from accumulating in the exhaust pipe.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0010] An embodiment according to the present invention is an exhaust pipe structure 10 of an internal combustion engine that is disposed below a floor panel of a vehicle 1, extends along a horizontal direction in a side view of the vehicle, and includes an exhaust pipe 20 that allows exhaust gas to flow rearward of the vehicle. The exhaust pipe 20 is provided with bulging portions 100a to 100c that bulge upward from a bottom 53 inside. When the condensed water accumulated in the exhaust pipe 20 comes into contact with the bulging portions 100a to 100c, the frozen condensed water can be easily melted or the condensed water can be evaporated. Therefore, since the condensed water in the exhaust pipe 20 can be eliminated, condensed water can be prevented from accumulating in the exhaust pipe 20.

Examples

[0011] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. <First Embodiment> FIG. 1 is a diagram showing a schematic configuration of a vehicle 1 equipped with an exhaust pipe structure 10 of an internal combustion engine according to the present embodiment. In each figure including FIG. 1, the forward side of the vehicle 1 is taken as the front, indicated by the arrow "front", and the reverse side is taken as the rear. Also, the upper side is indicated by the arrow "up", the reverse side is taken as the lower side, the left side is indicated by the arrow "left", and the reverse side is taken as the right side.

[0012] The vehicle 1 is equipped with an engine 2 as an internal combustion engine. The engine 2 burns a mixture of air and fuel to transmit a driving force to the wheels 3 and make the vehicle 1 run. The exhaust gas generated by the engine 2 burning the mixture is discharged to the outside through the exhaust pipe structure 10.

[0013] The exhaust pipe structure 10 of the present embodiment includes an exhaust pipe 20 and a muffler 70 or the like that performs sound absorption. The exhaust pipe 20 is a pipe that allows the exhaust gas to flow rearward of the vehicle. The main part of the exhaust pipe 20 is arranged below the floor panel of the vehicle and extends along the horizontal direction in a side view of the vehicle. Specifically, the exhaust pipe 20 of the present embodiment is continuously configured by a first exhaust pipe section 30, a second exhaust pipe section 40, a third exhaust pipe section 50, and a fourth exhaust pipe section 60.

[0014] The first exhaust pipe section 30 is connected to an exhaust port (not shown) of the engine 2. The first exhaust pipe section 30 is curved as a whole so as to be convex downward. Specifically, the first exhaust pipe section 30 is formed to curve downward from the front surface of the engine 2 and then pass below the engine 2 while curving toward the rear of the vehicle 1.

[0015] The second exhaust pipe section 40 is connected to the rear end of the first exhaust pipe section 30. The second exhaust pipe section 40 is gently curved as a whole so as to be convex upward. Specifically, the second exhaust pipe section 40 is formed to incline upward from the first exhaust pipe section 30, then extend along the horizontal direction, and then incline downward.

[0016] The third exhaust pipe section 50 is coupled to the rear end of the second exhaust pipe section 40. The third exhaust pipe section 50 is formed to extend along the horizontal direction in a side view of the vehicle. Further, the third exhaust pipe section 50 is located in a section where the height position in the vehicle's vertical direction of the exhaust pipe 20 is the lowest. Furthermore, the third exhaust pipe section 50 is located between the front wheel 3 and the rear wheel 3.

[0017] The fourth exhaust pipe section 60 is coupled to the rear end of the third exhaust pipe section 50. The fourth exhaust pipe section 60 is curved gently as a whole so as to bulge upward. Specifically, the fourth exhaust pipe section 60 is formed to be inclined upward from the third exhaust pipe section 50 and then inclined downward to be connected to the muffler 70.

[0018] In the exhaust pipe structure 10 configured as described above, the exhaust gas from the engine 2 can flow rearward of the vehicle via the first exhaust pipe section 30, the second exhaust pipe section 40, the third exhaust pipe section 50, and the fourth exhaust pipe section 60. However, the specific configuration of the exhaust pipe structure 10 is not limited and can be changed as appropriate according to the vehicle 1.

[0019] Here, a bulging portion 100 that functions so that condensed water does not accumulate is provided in the third exhaust pipe section 50 of the exhaust pipe 20 of the present embodiment. Hereinafter, the specific configuration of the bulging portion 100 will be described.

[0020] FIG. 2 is a perspective view showing an example of the configuration around the third exhaust pipe section 50 of the exhaust pipe 20. In FIG. 2, since the second exhaust pipe section 40 is shown by a two-dot chain line (virtual line), the front end of the third exhaust pipe section 50 is exposed and shown. FIG. 3 is a cross-sectional view of the third exhaust pipe section 50 of the exhaust pipe 20, and is a cross-sectional view taken by cutting in the vertical direction along the line I-I of FIG. 2 and viewed from the arrow direction.

[0021] The third exhaust pipe portion 50 is substantially cylindrical, and exhaust gas flows inside. In the present embodiment, the third exhaust pipe portion 50 is formed such that a plurality (here, three) of bulging portions 100 bulge upward from the bottom portion 53. The three bulging portions 100 are referred to as bulging portions 100a, 100b, and 100c in order from the left side.

[0022] As shown in FIG. 2, the bulging portions 100a to 100c are shaped to extend along the flow direction of the exhaust gas as a whole. That is, the bulging portions 100a to 100c extend in parallel with the extending direction of the third exhaust pipe portion 50. In the present embodiment, since the third exhaust pipe portion 50 extends along the front-rear direction, the bulging portions 100a to 100c also extend along the front-rear direction in the same manner.

[0023] As shown in FIG. 3, the bulging portions 100a to 100c are substantially triangular or substantially mountain-shaped when viewed from the extending direction (front-rear direction) of the third exhaust pipe portion 50. That is, the bulging portions 100a to 100c are formed to taper upward from the bottom portion 53. Here, when the bulging portions 100a to 100c of the present embodiment are triangular, the height is larger than the length of the base, that is, a triangular shape that is long in the vertical direction. Also, for each of the bulging portions 100a to 100c, the upper end 101 is located below the cross-sectional center O (refer to the dashed-dotted line shown in FIG. 3) of the third exhaust pipe portion 50.

[0024] Among the three bulging portions 100a to 100c, the bulging portion 100b is located at the center in the left-right direction, and the bulging portions 100a and 100c are located apart from the left and right of the bulging portion 100b. The left bulging portion 100a and the right bulging portion 100c are substantially symmetric in shape. Among the three bulging portions 100a to 100c, the lower ends of adjacent bulging portions 100 are in contact or close to each other. Also, the shapes of the bulging portions 100a to 100c when viewed from the extending direction of the third exhaust pipe portion 50 are substantially the same regardless of the position at which they are cut in any position in the extending direction of the third exhaust pipe portion 50.

[0025] Further, the bulges 100a to 100c can be fixed to the bottom 53 by welding the lower ends on both the left and right sides of a metal plate bent into a substantially triangular shape to the inner peripheral surface of the bottom 53. However, the bulges 100a to 100c may be integrally formed with the third exhaust pipe portion 50 by bending the bottom 53 itself of the third exhaust pipe portion 50, and the method of forming the bulges 100a to 100c is not limited.

[0026] In addition, the front and rear ends of the bulges 100a to 100c in this embodiment are each closed. That is, the bulges 100a to 100c are configured so that the exhaust gas does not flow inside the bulges 100a to 100c. Therefore, even when the water vapor contained in the exhaust gas condenses into condensed water w due to a temperature change or the like, as shown in FIG. 3, it does not accumulate inside the bulges 100a to 100c, but accumulates outside the bulges 100a to 100c, that is, in contact with the outer surfaces of the bulges 100a to 100c. Specifically, as shown in FIG. 3, the condensed water w accumulates between the bulge 100a and the bulge 100b or between the bulge 100b and the bulge 100c. Further, the condensed water w accumulates between the bulge 100a and the inner peripheral surface on the left side of the third exhaust pipe portion 50 or between the bulge 100c and the inner peripheral surface on the right side of the third exhaust pipe portion 50.

[0027] Next, the operation of the bulges 100a to 100c that function so that condensed water does not accumulate in the exhaust pipe 20 will be described. First, here, it is assumed that the water vapor contained in the exhaust gas in the exhaust pipe 20 becomes condensed water w due to a temperature change or the like. At this time, the condensed water w will accumulate in the third exhaust pipe portion 50, which is the section where the height position in the vehicle up and down direction is the lowest in the exhaust pipe 20. Since the third exhaust pipe portion 50 has the bulges 100a to 100c, as shown in FIG. 3, the condensed water w accumulates in a state of being in contact with the outer surfaces of the bulges 100a to 100c. Also, when the driving of the engine 2 is stopped in the accumulated state, the condensed water w may freeze depending on the outside air temperature.

[0028] Thus, even when condensate accumulates or freezes in the third exhaust pipe portion 50 of the exhaust pipe 20, when the engine 2 is started, the exhaust gas flowing through the exhaust pipe 20 warms the exhaust pipe 20 and the bulging portions 100a to 100. The condensed water that has accumulated or frozen in the third exhaust pipe portion 50 is in wide contact with the outer surfaces of the bulging portions 100a to 100c. Therefore, the heat of the bulging portions 100a to 100c can melt the frozen condensed water w or evaporate the condensed water w. Further, when the exhaust gas flows through the bulging portions 100a to 100c, the pressure becomes high on the upstream side of the bulging portions 100a to 100c, and the wind force increases after passing through the bulging portions 100a to 100c, so that the easily frozen condensed water w can be easily melted or the condensed water w can be evaporated.

[0029] As described above, in the exhaust pipe structure 10 of the present embodiment, the bulging portions 100a to 100c that bulge upward from the bottom portion 53 are provided inside the exhaust pipe 20. Therefore, compared with the conventional exhaust pipe, the area of contact between the condensed water accumulated in the exhaust pipe 20 and the exhaust pipe 20 increases, so that the easily frozen condensed water can be easily melted or the condensed water can be evaporated. Further, the pressure becomes high on the upstream side of the bulging portions 100a to 100c, and the wind force increases after passing through the bulging portions 100a to 100c, so that the easily frozen condensed water can be easily melted or the condensed water can be evaporated. Therefore, since the condensed water in the exhaust pipe 20 can be eliminated, it is possible to prevent the condensed water from accumulating in the exhaust pipe 20.

[0030] Further, according to the above-described embodiment, the bulging portions 100a to 100c are provided in the third exhaust pipe portion 50 which is at least the section where the height position of the exhaust pipe 20 in the vehicle up-and-down direction is the lowest. Since condensed water accumulates by gravity in the section where the height position in the vehicle up-and-down direction is the lowest, by providing the bulging portions 100a to 100c at this part, thawing of the frozen condensed water and evaporation of the condensed water can be effectively performed. Further, the bulging portions 100a to 100c are shaped to extend along the flow direction of the exhaust gas. Therefore, since the area of the outer surface of the bulging portions 100a to 100c increases, the contact area with the condensed water can also be increased. Also, when the frozen condensed water thaws, it can be prevented from accumulating again at a location different from this section. In the above-described embodiment, the case where the bulging portions 100a to 100c are provided in the third exhaust pipe portion 50 has been described, but this is not limiting, and they may be provided in the whole or part of at least any one of the first exhaust pipe portion 30, the second exhaust pipe portion 40, the third exhaust pipe portion 50, and the fourth exhaust pipe portion 60.

[0031] Further, according to the above-described embodiment, the upper ends of the bulging portions 100a to 100c are located below the cross-sectional center O of the exhaust pipe 20. Therefore, since a space can be formed above the exhaust pipe 20, it is possible to prevent blocking of the flow path of the exhaust gas and suppress an increase in exhaust resistance more than necessary.

[0032] <Second Embodiment> In the second embodiment, bulging portions 200a to 200c different in shape from the bulging portions 100a to 100c of the first embodiment will be described. FIG. 4(a) is a cross-sectional view of the third exhaust pipe portion 150 of the second embodiment and is a view showing the configuration of the bulging portions 200a to 200c.

[0033] The third exhaust pipe portion 150 of the present embodiment is a double pipe composed of an inner pipe 151 and an outer pipe 152. A space is formed between the inner pipe 151 and the outer pipe 152. The third exhaust pipe portion 150 is formed with a plurality (here, three) of bulging portions 200 bulging upward from the bottom 153. The three bulging portions 200 are referred to as bulging portion 200a, 200b, and 200c in order from the left side.

[0034] The bulges 200a to 200c are shaped to extend along the flow direction of the exhaust gas as a whole. Also, as shown in Fig. 4(a), the bulges 200a to 200c are substantially U-shaped when viewed from the extending direction of the third exhaust pipe portion 150. That is, in the bulges 200a to 200c, a pair of side walls 201 extend substantially parallel upward from the bottom 153, and the upper ends are connected in a substantially horizontal direction by an upper wall 202.

[0035] Also in this embodiment, similar to the first embodiment, the condensed water or frozen condensed water accumulated in the third exhaust pipe portion 150 comes into wide contact with the outer surfaces of the bulges 200a to 200c, so that the frozen condensed water can be easily melted or the condensed water can be evaporated.

[0036] Further, in the third exhaust pipe portion 150, at least the section having the bulges 200a to 200c is made into a double pipe. Therefore, since the condensed water accumulated in the third exhaust pipe portion 150 does not directly contact the outside air, it is possible to suppress the temperature of the condensed water from becoming low or freezing. As shown in Fig. 4(a), a heat insulation cover 155 may be provided on the outer peripheral surface of the inner pipe 151 in at least the section having the bulges 200a to 200c. When the heat insulation cover 155 is provided, the outer pipe 152 may be omitted.

[0037] <Third Embodiment> In the third embodiment, the bulges 300a to 300c, which are different in shape from the bulges 100a to 100c of the first embodiment, will be described. Fig. 4(b) is a cross-sectional view of the third exhaust pipe portion 250 of the third embodiment and shows the configuration of the bulges 300a to 300c.

[0038] The third exhaust pipe section 250 of this embodiment is a double pipe composed of an inner pipe 251 and an outer pipe 252. A space is formed between the inner pipe 251 and the outer pipe 252. From the bottom 253, a plurality (here, three) of bulging portions 300 bulge upward to form the third exhaust pipe section 250. The three bulging portions 300 are referred to as bulging portions 300a, 300b, and 300c in order from the left side.

[0039] The bulging portions 300a to 300c are shaped to extend along the flow direction of the exhaust gas as a whole. Also, as shown in FIG. 4(b), the bulging portions 300a to 300c are wavy when viewed from the extending direction of the third exhaust pipe section 250. That is, the bulging portions 300a to 300c are formed to taper while meandering left and right upward from the bottom 253.

[0040] Similar to the first embodiment, even in this embodiment, the condensed water or frozen condensed water accumulated in the third exhaust pipe section 250 can easily melt the frozen condensed water or evaporate the condensed water because it comes into wide contact with the outer surfaces of the bulging portions 300a to 300c.

[0041] Also, in the third exhaust pipe section 250, at least the section having the bulging portions 300a to 300c is made into a double pipe. Therefore, since the condensed water accumulated in the third exhaust pipe section 250 does not directly contact the outside air, it is possible to suppress the temperature of the condensed water from becoming low or freezing. As shown in FIG. 4(b), a heat insulation cover 255 may be provided on the outer peripheral surface of the inner pipe 251 in at least the section having the bulging portions 300a to 300c. When the heat insulation cover 255 is provided, the outer pipe 252 may be omitted.

[0042] The embodiments according to the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and changes and the like are possible within the scope of the present invention. For example, a part of an embodiment can be combined with other embodiments.

[0043] The numbers of the bulging portions 100a to 100c, 200a to 200c, and 300a to 300c in the above-described embodiments are not particularly limited and can be changed as appropriate. In the exhaust pipe structure 10 in the above-described embodiments, the case where it has the exhaust pipe 20 and the muffler 70 that performs silencing has been described. However, it is not limited to this case, and alternatively, it may have a catalytic converter, a sub-muffler, or the like.

[0044] The bulging portions 100a to 100c of the above-described embodiments have been described for the case where the front end and the rear end are each closed. However, it is not limited to this case, and they may be open. Therefore, the exhaust gas may also flow into the bulging portions 100a to 100c, and further, the condensed water may be configured to accumulate inside the bulging portions 100a to 100c.

Explanation of Reference Numerals

[0045] 1: Vehicle 2: Engine (internal combustion engine) 10: Exhaust pipe structure 20: Exhaust pipe 50, 150, 250: Third exhaust pipe portion 53, 153, 253: Bottom portion 70: Muffler 100 (100a to 100c), 200 (200a to 200c), 300 (300a to 300c): Bulging portion 101: Upper end 151, 251: Inner pipe 152, 252: Outer pipe 155, 255: Heat insulation cover

Claims

1. An exhaust pipe structure of an internal combustion engine, which is disposed below a floor panel of a vehicle, extends along a horizontal direction in a side view of the vehicle, and allows exhaust gas to flow rearward of the vehicle, wherein the exhaust pipe, is characterized in that a bulging portion bulging upward from a bottom is provided inside. An exhaust pipe structure of an internal combustion engine.

2. The bulging portion, is provided at least in a section where the height position of the exhaust pipe in the vehicle's vertical direction is the lowest, and has a shape extending along the flow direction of the exhaust gas. The exhaust pipe structure of the internal combustion engine according to claim 1.

3. The bulging portion, is characterized in that the upper end is located below the cross-sectional center of the exhaust pipe. The exhaust pipe structure of the internal combustion engine according to claim 1 or 2.

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