JP6692656B2 - Internal combustion engine exhaust adapter - Google Patents

Description

  The present invention relates to an exhaust adapter that is interposed between a cylinder head of an internal combustion engine and an exhaust manifold.

For example, in an internal combustion engine for a vehicle, in order to protect the catalyst for purifying exhaust gases lowers the temperature of the exhaust gas, by arranging the exhaust adapter between the cylinder head and the exhaust manifold, the exhaust through the cooling water into the exhaust adapter It is known to lower the temperature of the gas (note that the exhaust adapter can also contribute to the early temperature rise of the cooling water during warm-up operation).

  It can be said that the thickness of the exhaust adapter should be increased in order to enhance the cooling performance of the exhaust gas by the exhaust adapter, but this increases the weight of the internal combustion engine and deteriorates the fuel consumption. Therefore, it is considered to enhance the cooling performance without increasing the thickness, and as an example thereof, in Patent Document 1, the exhaust gas passage of the exhaust adapter is tapered so that the cross-sectional area decreases from the inlet to the outlet. It is disclosed that the cooling water passage is formed and the cross-sectional area increases from the inlet side to the outlet side of the exhaust gas passage.

JP, 2013-36448, A

  Patent Document 1 attempts to efficiently cool the exhaust gas while suppressing the pressure loss on the outlet side by utilizing the fact that the volume of the exhaust gas decreases as the exhaust gas cools. Since the exhaust gas discharged from the port passes straight through the exhaust gas passage, it is feared that most of the exhaust gas will pass through without being in contact with the inner surface of the exhaust gas passage, which demonstrates high cooling performance. I doubt if I can do it.

  Further, if the cooling property of the exhaust gas is low, the volume reduction rate of the exhaust gas is also low. Therefore, it can be said that the question remains as to whether the exhaust gas passes through the exhaust adapter without pressure loss.

  The present invention has been made to improve the present situation.

The present invention relates to an exhaust adapter arranged between an exhaust side surface of a cylinder head and an exhaust manifold.
"Inside, an exhaust gas passage communicating with the exhaust port of the cylinder head and a branch pipe of the exhaust manifold, and a cooling water passage for cooling the exhaust gas passage are formed,
The exhaust gas passage, by the entry and exit of tilting between the two in a posture orthogonal to the exhaust side of the cylinder head, the inlet is offset at least in the vertical direction so as to the outlet becomes high low While
The cooling water passage has a constricted portion located between the inlet and the outlet of the exhaust gas passage, the cross-sectional area of the portion located on the outlet side of the exhaust gas passage across the constricted portion, It is larger than the cross-sectional area of the part located on the inlet side of the exhaust gas passage. "
Is configured.

As an offset mode between the inlet and outlet of the exhaust gas passage, when viewed from the direction orthogonal to the exhaust side surface of the cylinder head (direction orthogonal to the cylinder bore axis and the crank axis), it can be shifted only in the vertical direction or in the vertical direction and the horizontal direction. It is possible to adopt any mode such as shifting to both. It is also possible to make the offset modes of the plurality of exhaust gas passages different from each other.

In the present invention, since the exhaust gas passage has the inlet and the outlet orthogonal to the exhaust side surface of the cylinder head and the inlet and the outlet are offset at least in the vertical direction, the exhaust gas passage is inclined inside the exhaust adapter. Therefore, the surface area of the exhaust gas passage becomes larger than that in the case where the inlet and the outlet are concentrically arranged as in Patent Document 1. Further, since the exhaust gas discharged from the exhaust port of the cylinder head changes its direction in the exhaust gas passage, a mixing action of the exhaust gas occurs inside the exhaust gas passage, so that the contact property of the exhaust gas with the inner surface of the exhaust gas passage is reduced. It dramatically increases.

  As described above, the increase in the surface area of the exhaust gas passage and the marked increase in the contact property of the exhaust gas with the inner surface of the exhaust gas passage contribute to the exhaust gas without increasing the thickness of the exhaust adapter. Coolability can be improved. Further, it is also possible to promote the uniformization of the temperature of the exhaust gas.

Further, since it is possible to easily provide a swirling flow to the exhaust gas by utilizing the direction change of the exhaust gas, it is possible to enhance the mixing property of the exhaust gas and further promote the homogenization of the temperature of the exhaust gas, As a result, the burden on the exhaust gas purifying catalyst can be lightened and the durability can be improved. Also, being able to give a swirl flow to the exhaust gas contributes to smoothing the flow of the exhaust gas, and as a result, not only can pressure loss be suppressed and fuel efficiency can be improved, but the acceleration response of the vehicle can also be improved. Can also contribute to the improvement of
Further, since the exhaust gas passage is formed so that the inlet is low and the outlet is high, even if condensed water is generated in the exhaust gas passage after the engine is stopped, the generated condensed water passes through the exhaust manifold to the catalyst. There is an advantage that it can be prevented from dropping. Further, when the outlet of the exhaust gas passage is high, the exhaust gas hits the outlet side of the exhaust gas passage strongly, but in the present invention, the cross-sectional area is large on the outlet side of the cooling water passage exhaust gas passage. In the exhaust gas passage, the portion where the exhaust gas hits strongly is cooled strongly. Therefore, it has excellent cooling performance.

It is the side view which looked at the important section of the internal-combustion engine concerning an embodiment from the direction orthogonal to the crank axis and the cylinder bore axis. It is a right view of FIG. It is a separation side view. FIG. It is the figure which looked at the exhaust adapter from the back side. 6A is a sectional view taken along line VIA-VIA in FIG. 5, and FIG. 6B is a schematic view showing the flow of exhaust gas.

(1). Outline of Internal Combustion Engine Next, an embodiment of the present invention will be described with reference to the drawings. In the present embodiment, the state viewed from the crank axis direction is defined as a front view. Therefore, FIG. 1 is a side view as seen from the direction of the crank axis (cam axis direction) and the direction orthogonal to the cylinder bore axis. As a precaution, the direction is shown in FIG. First, the outline of the internal combustion engine will be described.

  The internal combustion engine of the present embodiment is for a vehicle (for an automobile), and has a cylinder lid 1 provided with a cylinder bore (not shown) and a cylinder head 2 fixed to the upper surface thereof as in the conventional case. An exhaust manifold 4 is fixed to the exhaust side surface 2a of the cylinder head 2 via a cast exhaust adapter 3. The internal combustion engine has four cylinders. Therefore, as shown in FIG. 3, on the exhaust side surface 2a of the cylinder head 2, four first to fourth exhaust ports 5 to 8 are opened in line from the end. There is. Each of the exhaust ports 5, 6, 7, and 8 has an oval shape with a longitudinal length.

  The exhaust manifold 4 has first to fourth four branch pipes 9 to 12 corresponding to the four exhaust ports 5 to 8, and the start ends of the branch pipes 9, 10, 11, 12 are flange plates. It is fixed to 4a. The first branch pipe 9 and the fourth branch pipes 9 and 12 are gathered in the first collecting pipe 13, and the second branch pipe 10 and the third branch pipe 11 are gathered in the second collecting pipe 14. These two collecting pipes 13 and 14 are connected to the upper end of the catalyst case 15.

  The first branch pipe 9 and the fourth branch pipe 12 are connected to the first set 13 via a three-way joint 16, and the second branch pipe 10 is welded to a middle portion of the third branch pipe 11. .. Therefore, the second collecting pipe 14 is composed of the terminal end portion of the third branch pipe 11. Although the exhaust manifold 4 of the embodiment is manufactured by welding pipes, a cast product may be used.

  The catalyst case 15 has a straight part in which a three-way catalyst is stored, and an upper part is an upper cone part 17 with an upper constriction (lower spread), and a lower part is a lower cone part 18 with a lower constriction. ing. A straight exhaust connection pipe 19 is connected to the lower end of the lower cone portion 18, and a fixing bracket 20 is integrally fixed to the exhaust connection pipe 19. Further, an EGR pipe 21 for recirculating a part of exhaust gas to the intake system is connected to the lower cone portion 18.

  The two collecting pipes 13 and 14 are arranged in the left-right direction orthogonal to the exhaust side surface 2 a of the cylinder head 2. Therefore, the upper end portion of the upper cone portion 15b of the catalyst case 15 has a shape elongated in the left-right direction, and the two collecting pipes 13 and 14 are connected to the upper end portion. Therefore, the lower end of the upper cone portion 17 has a circular shape, but the upper end has an oval shape. For this reason, although the upper cone portion 17 has an upper constriction as a whole, the degree of the upper constriction displayed in the side view of FIG. 1 becomes a tighter angle than the degree of the upper constriction shown in FIG. ing.

  In other words, the left and right surfaces of the upper cone portion 17 are gently sloping surfaces 17b, the front and rear surfaces are steeply sloping surfaces 17a, and the two sloping surfaces 17a and 17b converge in a circular shape toward the lower end. There is. Then, the hollow boss 22 is fixed to one steep slope 17a by welding, and the AF sensor (air-fuel ratio sensor) is attached to the hollow boss 22 by screwing.

(2). Exhaust adapter structure The exhaust adapter 3 is a thick plate or block and has a long front-rear appearance. As shown in FIG. 5, it corresponds to the first to fourth exhaust ports 5 to 8. And has first to fourth exhaust gas passages 24 to 27. Therefore, the exhaust adapter 3 includes the first to fourth inlets 28 to 31 corresponding to the exhaust ports 5 to 8 and the first to fourth outlets 32 to corresponding to the first to fourth branch pipes 9 to 12. 35.

  Each of the inlets 28 to 31 has the same oval shape as the exhaust ports 5 to 8, while each of the outlets 32 to 35 has the same circular shape as that of each of the branch pipes 9 to 12, and the sectional area is from the inlets 28 to 31 to the outlet 32. It is slightly smaller toward ~ 35.

  Further, as clearly shown in FIG. 5, the inlets 28 to 31 and the outlets 32 to 35 of the exhaust gas passages 24 to 27 are arranged in the vertical direction (the outlets 32 to 35 are higher than the inlets 28 to 31). The outlets 32 to 35 are offset (offset) in the front-rear direction (crank axis direction) with respect to the inlets 28 to 31 while being offset (offset) in the cylinder bore axial direction).

  In this case, the second outlet 33 and the third outlet 34 have almost the same height and are higher than the first outlet 32 and the fourth outlet 35. The first outlet 32 and the fourth outlet 35 have substantially the same height. In addition, the amounts of lateral displacement between the inlets 28 to 31 and the outlets 32 to 35 in the exhaust gas passages 24 to 27 are not uniform but different from each other. Further, the inlets 28 to 30 and the outlets 32 to 34 in the first to third exhaust gas passages 24 to 27 are respectively displaced in the same direction, but the inlet 31 and the outlet 35 of the fourth exhaust gas passage 28 are opposite to each other. Misaligned.

  In this way, the difference in the shift mode between the inlets 28 to 31 and the outlets 32 to 35 in each of the exhaust gas passages 24 to 27 is due to the form of the branch pipes 9, 10, 11, and 12. For example, the catalyst case 15 may be brought close to the end of the cylinder head 2, but in this case, since the positions of the collecting pipes 13 and 14 are changed, the inlets 28 to 31 and the outlets 32 to 31 of the exhaust gas passages 24 to 27 are The mode of deviation from 35 also changes.

As shown by the second exhaust gas passage 25 as a representative in FIG. 6 (A), the exhaust gas passages 24 to 27 have the cylinder head 2 near the inlets 28 to 31 and near the outlets 32 to 35. Is a straight portion orthogonal to the exhaust side surface 2a, and the portion connecting the two is bent so as to incline, whereby the outlets 32 to 35 are offset to be higher than the inlets 28 to 31. In reality, the bend is not two-dimensional but three-dimensional, and it is also possible to employ a spiral bend.

Inside the exhaust adapter 3, an upper cooling water passage 38 and a lower cooling water passage 39 are formed with the exhaust gas passages 24 to 27 interposed therebetween, and both cooling water passages 38, 39 are the first exhaust gas passages. It communicates with the outside of 24. A cooling water inlet 40 is provided at one end of the lower cooling water passage 39, and a cooling water outlet 41 is provided at one end of the upper cooling water passage 38. Therefore, the cooling water enters into one end of the lower cooling water passage 39 in the exhaust adapter 3 from below, makes a U-turn , flows into the other end of the upper cooling water passage 38, and is then discharged from the cooling water outlet 41. ..

The exhaust adapter 3 is fixed to the cylinder head 2 with stat bolts and nuts (neither is shown) at the five first mounting holes 42 shown by black circles in FIG. The exhaust manifold 4 is the location of the second attachment hole 43 of the seven locations indicated by hatching in FIGS. 1 and 3, the flanges 4a are fixed to the exhaust adapter 3 with bolts (not shown). Therefore, the second mounting hole 43 of the exhaust adapter 3 is a tap hole.

(3). Summary Exhaust gas from each exhaust port 5, 6, 7, 8 of the cylinder head 2 is cooled by cooling water in the process of passing through the exhaust gas passages 24 to 27 of the exhaust adapter 3. This can reduce the temperature of the exhaust gas and prevent damage to the catalyst.

  Further, in the present embodiment, the inlets 28 to 31 and the outlets 32 to 35 of the exhaust gas passages 24 to 27 are displaced (offset), so that the length of the exhaust gas passages 24 to 27 becomes long. As a result, the contact area of the exhaust gas is increased, and the exhaust gas flowing into the exhaust gas passages 24-27 is linearly changed in direction, so that the exhaust gas comes into contact with the inner surfaces of the exhaust gas passages 24-27. The nature is enhanced. Therefore, high cooling performance is exhibited.

  Since the exhaust gas passages 24 to 27 are curved and have a long length, the contact area between the exhaust gas passages 24 to 27 and the cooling water also increases. Also in this respect, the exhaust gas is excellently cooled.

  Further, since the exhaust gas is subjected to a strong stirring action as the exhaust gas changes its direction inside the exhaust gas passages 24 to 27, the temperature of the exhaust gas flowing into the catalyst case 15 is made uniform and damage to the catalyst is prevented. Or, it can be remarkably suppressed, and the thermal strain of the branch pipes 9, 10, 11, 12 can be suppressed.

  Further, since the inlets 28 to 31 and the outlets 32 to 35 of the exhaust gas passages 24 to 27 are deviated in both the front-rear direction and the vertical direction, as shown in FIG. The gas tends to swirl around the axes of the exhaust gas passages 24 to 27, which enhances the contactability of the exhaust gas with the inner surfaces of the exhaust gas passages 24 to 27 and the mixing property of the exhaust gas. Thus, the cooling property and the temperature uniformity can be promoted.

  That is, the inner surface of each of the exhaust gas passages 24 to 27 is an arcuate curved surface, and the exhaust gas passages 24 to 27 are directed obliquely upward toward the straight direction from the exhaust ports 5, 6, 7, 8. Due to the conversion, the exhaust gas is guided by the inner surfaces of the exhaust gas passages 24 to 27 to change its direction between the upper direction and the front-rear direction. Therefore, the exhaust gas forms a smooth curved surface of the exhaust gas passages 24 to 27. It is possible to say that a swirl flow is formed as a result of being guided and changing the direction around the axis of the exhaust gas passages 24-27. By forming the exhaust gas passages 24 to 27 in a spiral shape, a strong swirling flow can be surely applied to the exhaust gas.

  In addition, the swirl flow being imparted to the exhaust gas also means that the exhaust gas uniformly contacts the inner surfaces of the exhaust gas passages 24 to 27 and the branch pipes 9, 10, 11, and 12, whereby the exhaust gas is exhausted. The thermal strain of the adapter 3 and the branch pipes 9, 10, 11, 12 can be suppressed to contribute to the prevention of breakage.

  The branch pipes 9, 10, 11, 12 are bent downward from a substantially horizontal direction orthogonal to the outer surface of the exhaust adapter 3, but the branch pipes 9, 10, 11, 12 are connected to the collecting pipes 13, 14 respectively. Since the exhaust gas flows toward the end of the branch pipes 9, 10, 11, 12 since they are gathered together, the exhaust gas swirls around the axis of each branch pipe 9, 10, 11, 12. It can be said that there is a tendency.

That is, since the branch pipes 9, 10, 11, and 12 are bent downward in a state of approaching substantially the middle portion of the exhaust adapter 3, the straightness with respect to the starting ends of the branch pipes 9, 10, 11, and 12 is maintained. The exhaust gas that has flowed in is directed toward the terminal end while being guided by the inner surfaces of the branch pipes 9, 10, 11, 12, but since the branch pipes 9, 10, 11, 12 are bent in plan view, the exhaust gas is exhausted. It can be said that the gas turns toward the catalyst case 15 while swirling around the axes of the branch pipes 9, 10, 11, and 12.

In this embodiment, the inlets 28 to 31 and the outlets 32 to 35 of the exhaust gas passages 24 to 27 are straight portions that are orthogonal to the exhaust side surface 2a of the cylinder head 2, but are formed in this manner. Then , the lengths of the exhaust gas passages 24 to 27 can be further increased, so that the cooling performance can be further improved. In addition, the presence of the straight portion on the side of the inlets 28 to 31 smoothly guides the flow of the exhaust gas, so that the exhaust gas is prevented from excessively hitting a specific portion near the inlets of the exhaust gas passages 24 to 27. Thus, the heat damage to the exhaust adapter 3 can be prevented.

In addition, the straight portion on the side of the outlets 32 to 35 is substantially parallel to the starting end portions of the branch pipes 9, 10, 11, 12 so that the exhaust gas can be discharged onto one of the inner surfaces of the branch pipes 9, 10, 11, 12. It is possible to suppress hitting the part strongly. Thereby, the thermal distortion of the branch pipes 9, 10, 11, 12 can be suppressed, and the adverse effects such as breakage can be prevented.

Exhaust gas passage 24 to 27, the higher the exit 32 to 35 from the inlet 28 to 31 as implementation form, even if condensed water generated in the exhaust gas passage 24 to 27 after the engine is stopped, the condensed water is generated There is an advantage that it can prevent the catalyst from dripping. Further, since heat has a property of escaping upward, tilting the exhaust gas passages 24 to 27 upward as in the embodiment can also contribute to suppression of thermal strain of the exhaust adapter 3.

The exhaust gas changes its direction at the outlets 32-35 of the exhaust gas passages 24-27 and flows into the branch pipes 9, 10, 11, 12, so that the exhaust gas exits 32-35 of the exhaust gas passages 24-27. 6, the cooling water passages 38 , 39 have constricted portions 38a, 39a located between the inlets 28-31 and the outlets 32-35 of the exhaust gas passages 24-27 , as shown in FIG. Since the cross-sectional areas of the inlets 28 to 31 side across the narrowed portions 38a and 39a are small and the cross-sectional areas of the outlets 32 to 35 side across the narrowed portions 38a and 39a are large , In the exhaust gas passages 24 to 27, the part where the exhaust gas hits strongly is cooled strongly. Also in this respect, the cooling performance is excellent.

Although the embodiments of the present invention have been described above, the present invention can be embodied in various other ways. For example, the number of cylinders of the internal combustion engine is not limited to four cylinders, and can be applied to other multi-cylinder internal combustion engines . The exhaust gas passages may be formed in the same displacement mode.

  The present invention can be actually embodied in an exhaust adapter for an internal combustion engine. Therefore, it can be used industrially.

2 Cylinder head 2a Exhaust side face 3 Exhaust adapter 4 Exhaust manifold 5-8 Exhaust port 9-12 Exhaust manifold branch pipe 13,14 Exhaust manifold collecting pipe 15 Catalyst case 24-27 Exhaust gas passage inside exhaust adapter 28-31 Exhaust Gas passage inlet 32 to 35 Exhaust gas passage outlet 38,39 Cooling water passage
38a, 39a constriction

Claims (1)

An exhaust adapter arranged between the exhaust side surface of the cylinder head and the exhaust manifold,
Inside, an exhaust gas passage communicating with an exhaust port of the cylinder head and a branch pipe of the exhaust manifold, and a cooling water passage for cooling the exhaust gas passage are formed,
The exhaust gas passage is offset at least in the vertical direction so that the inlet and the outlet are inclined so that the inlet and the outlet are high by inclining the inlet and the outlet in a posture orthogonal to the exhaust side surface of the cylinder head. While
The cooling water passage has a constricted portion located between the inlet and the outlet of the exhaust gas passage, the cross-sectional area of the portion located on the outlet side of the exhaust gas passage across the constricted portion, It is larger than the cross-sectional area of the portion located on the inlet side of the exhaust gas passage,
Exhaust adapter for internal combustion engine.

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