JP2018132001A - Cylinder head for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cylinder head for an engine in which an exhaust manifold that is made more compact is built-in, while securing a smooth exhaust characteristic.SOLUTION: Plural exhaust ports 10 individually connected to plural cylinders 6 are built-in a cylinder head for an engine. The number of the cylinders 6 is 3 or more, and one exhaust port 10 and the other exhaust port 10 among the plural exhaust ports 10 are joined to constitute confluent ports 12. The confluence ports 12 are overlaid on each other in an upward and downward direction at an upper side than the other exhaust port 10 further different from one exhaust port 10 and the other exhaust port 10 among the plural exhaust ports 10.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an engine cylinder head incorporating an exhaust manifold.

  As an engine cylinder head, for example, as shown in Patent Documents 1 and 2, an exhaust manifold integrated type in which a plurality of exhaust ports connected to each cylinder of the engine are built in the cylinder head has been developed. . By incorporating the exhaust port in the cylinder head, the exhaust port and the cooling system provided in the cylinder head can be brought close to each other, the exhaust gas cooling efficiency can be improved, and the exhaust system can be made compact. be able to.

JP 2008-38838 A JP 2006-53311 A

  In the configurations according to Patent Documents 1 and 2, the exhaust ports are gathered in the horizontal direction while maintaining a state in which the exhaust ports are arranged in parallel along the arrangement direction of the cylinders (see FIG. 1 of Patent Document 1 and Patent Document 2). (See FIG. 1). For this reason, there is a problem that it is necessary to secure a space for arranging the exhaust ports in the direction in which they are arranged in parallel, and it is difficult to further downsize the exhaust system. Further, by collecting the exhaust ports along the arrangement direction of the cylinders, exhaust gas pipes from the cylinders to the catalyst device for exhaust purification include cylinders close to the collection position and cylinders far from the collection position. There is a difference in length, which may impair purification efficiency and smooth exhaust gas exhaustion.

  Accordingly, an object of the present invention is to further reduce the size of the cylinder head while ensuring smooth exhaust characteristics of the cylinder head incorporating the exhaust manifold.

  In order to solve the above problems, in the present invention, in an engine cylinder head incorporating a plurality of exhaust ports connected to a plurality of cylinders, the number of cylinders of the cylinder is 3 or more, and the plurality of cylinders One exhaust port in the exhaust port and another exhaust port merge to form a merge port, and the merge port is defined as the one exhaust port and the other exhaust port in the plurality of exhaust ports. An engine cylinder head is provided, which is disposed so as to overlap vertically above another further exhaust port.

  In the above configuration, when the number of cylinders of the cylinder is 4, and the exhaust ports connected to the cylinders are the first port, the second port, the third port, and the fourth port in the order of arrangement. In addition, it is preferable that the merging port is constituted by merging of the second port and the third port.

  In the configuration in which the merging port is configured by the merging of the second port and the third port, the first port and the fourth port are arranged below the merging port while being horizontally parallel, and the merging port The port, the first port, and the fourth port are partitioned by a T-shaped partition when viewed from the gas flow direction of each port, and a cooling water channel along the T-shape is formed inside the partition. It is preferable that the structure is formed.

  In each of the above configurations, the aspect ratio of the cross section of the exhaust port other than the exhaust ports constituting the merge port is the horizontal aspect ratio with respect to the vertical direction of the cross section by the vertical plane with respect to the gas flow direction at the outlet portion of the merge port. It is preferable to use a larger configuration.

  According to the present invention, the plurality of exhaust ports are arranged so as to overlap in the vertical direction, and the offset amount in the vertical direction is made different, so that the exhaust gas piping connected to each cylinder corresponds to the offset amount. The length (the length from each cylinder to the catalyst device) can be made similar, and smooth exhaust gas exhaust can be ensured. In addition, by combining one exhaust port with the other exhaust port among the plurality of exhaust ports, the exhaust system is more compact than when the exhaust ports are assembled along the arrangement direction of each cylinder. Can be achieved.

Exploded perspective view showing an example of engine cylinder head and cylinder block Sectional drawing which shows an example of the internal structure of the engine shown in FIG. The front view which shows 1st embodiment (core) of the cylinder head for engines which concerns on this invention Sectional drawing which follows the IV-IV line in FIG. Bottom view showing the core of the exhaust port shown in FIG. The figure which shows the positional relationship between a cylinder head and a catalyst apparatus. 2 shows a second embodiment (core) of an engine cylinder head according to the present invention, where (a) is a front view and (b) is a bottom view. FIG. The perspective view of the cylinder head (core) shown in FIG. 7 is an exploded perspective view of the cylinder head (core) shown in FIG. 7A is a sectional view taken along line AA, FIG. 7B is a sectional view taken along line BB, FIG. 7C is a sectional view taken along line CC, and FIG. Sectional view along the line

  An engine cylinder head according to the present invention (hereinafter abbreviated as “cylinder head”) is applied to the engine illustrated in FIGS. 1 and 2. As shown in FIG. 1, this engine is an in-line four-cylinder engine in which four cylinders 6 (first cylinder 6a, second cylinder 6b, third cylinder 6c, and fourth cylinder 6d) are arranged in series. A cylinder head 1 and a cylinder block 2 are provided. The cylinder head 1 is an exhaust manifold integrated cylinder head 1 having a built-in exhaust port 10. An engine is constructed by connecting the cylinder head 1 to a cylinder block 2. Hereinafter, the cylinder head 1 side of the engine is referred to as an upper side, and the cylinder block 2 side is referred to as a lower side.

  As shown in FIG. 2, a water chamber 11 (water jacket) through which cooling water flows is formed inside the engine, and the engine is cooled by flowing cooling water through the water chamber 11. A piston 4 is provided in the cylinder 3 so as to be movable up and down. An intake port 5 for sending air and an exhaust port 10 for discharging exhaust gas are connected to the combustion chamber above the piston 4. In this figure, descriptions of engine accessory parts such as intake / exhaust valves and ignition devices are omitted. It should be noted that the form of the engine shown here is merely an illustrative example, and the cylinder head 1 according to the present invention, which will be described below, is limited in terms of the number of cylinders of the engine, the shape of the water chamber 11, and the like. Applied without.

  A first embodiment of a cylinder head 1 according to the present invention will be described with reference to FIGS. Each of these drawings shows the outer shape of the exhaust port 10 and the water chamber 11 formed in the cylinder head 1 (the shape of the core used when the cylinder head 1 is cast, that is, the cavity formed by casting. Part shape). The exhaust ports 10 and the exhaust port 10 and the water chamber 11 are partitioned by a partition wall (not shown) formed by casting, exhaust gas is contained in the exhaust port 10, and cooling water is contained in the water chamber 11. Flowing.

  The water chamber 11 is disposed so as to surround each exhaust port 10 from the top, bottom, left, and right in a front view. Cooling water is circulated in the water chamber 11 by a water pump (not shown). As a result, the exhaust gas flowing through each exhaust port 10 provided close to the water chamber 11 is cooled.

  The cylinder head 1 includes a plurality of exhaust ports 10 (first port 10a, second port 10b, third port 10c, and fourth port 10d) connected to the plurality of cylinders 6, respectively. This cylinder head 1 is for an in-line four-cylinder engine, and each cylinder 6 (first cylinder 6a, second cylinder 6b, third cylinder 6c, fourth cylinder 6d) has a first port 10a and a second port 10b. The third port 10c and the fourth port 10d are connected in the order in which the cylinders 6 are arranged.

  As shown in FIGS. 3 to 5, each exhaust port 10 is gathered near the center in the arrangement direction of the plurality of cylinders 6 arranged in series (near the middle between the second cylinder 6b and the third cylinder 6c). The second port 10b and the third port 10c join together in the middle to form the joining port 12, while the first port 10a and the fourth port 10d do not join with the other exhaust ports 10 and are independent from each other. It is gathered as it is. In this collective position, the merge port 12 is disposed so as to overlap the upper side of the first port 10a and the fourth port 10d.

  For example, in an in-line four-cylinder engine, combustion occurs in the order of the first cylinder 6a, the third cylinder 6c, the fourth cylinder 6d, and the second cylinder 6b every time a crankshaft (not shown) rotates 180 degrees. That is, the second cylinder 6b and the third cylinder 6c are out of phase by 360 degrees in the rotation angle of the crankshaft, and are connected to the second port 10b connected to the second cylinder 6b and the third cylinder 6c. Even if the third ports 10c are merged, no exhaust interference occurs in the exhaust stroke. For this reason, problems such as residual exhaust gas in the cylinder 6 due to exhaust interference and occurrence of knocking when the compression ratio is high are avoided.

  As shown in FIG. 3, when the horizontal plane including the average center position in the vertical direction of the bent portion of each exhaust port 10 in the horizontal direction at the connection portion of the exhaust port 10 to each cylinder 6 is defined as the horizontal reference plane f. The merge port 12 is offset by Δdu upward from the horizontal reference plane f, and the first port 10a and the fourth port 10d are offset by Δdl downward from the horizontal reference plane f. This offset amount is larger in Δdu than in Δdl.

  In the cylinder head 1 according to the first embodiment, the exhaust ports 10 are assembled near the middle between the second cylinder 6b and the third cylinder 6c. In this case, the horizontal distance from each cylinder 6 to the collection position is shorter in the second port 10b and the third port 10c (merging port 12) than in the first port 10a and the fourth port 10d. Therefore, as described above, the offset amount Δdu of a part of the exhaust ports 10 (here, the merging port 12 (second port 10b and third port 10c)) is set to another exhaust port (here By making it larger than the offset amount Δdl of the first port 10a and the fourth port 10d), the second port 10b constituting the confluence port 12 in the cylinder head 1 based on the difference (Δdu−Δdl) between the two offset amounts. And the port length of the 3rd port 10c can be extended relatively compared with the case where it does not offset.

  As shown schematically in FIG. 6, generally, the catalyst device 7 is often connected to the lower side with respect to the cylinder head 1, and the merging port 12 (second port 10 b) in the cylinder head 1. Further, by offsetting the third port 10c) upward, the length of the exhaust gas pipe 8 connecting the cylinder head 1 and the catalyst device 7 outside the cylinder head 1 is compared with the case where it is not offset. Can be relatively extended.

  The length of the exhaust gas pipe connected to the second cylinder 6b and the third cylinder 6c (the second port 10b or the third port 10c (merging port 12)) and the exhaust gas pipe line 8 inside and outside the cylinder head 1 The length of the exhaust gas pipe and the length of the exhaust gas pipe connected to the first cylinder 6a and the fourth cylinder 6d (the first port 10a or the fourth port 10d and the exhaust gas) The total length of the gas pipes 8) can be made similar. In this way, the flow of exhaust gas from the engine to the catalyst device 7 becomes smooth, and exhaust interference can be surely prevented, and various types of sensors such as an air-fuel ratio sensor and an oxygen concentration sensor provided in the catalyst device 7 can be obtained. The sensitivity of the sensor 9 can be improved.

  As shown in FIG. 3, the shape of the outlet portion of the joining port 12 formed by joining the second port 10 b and the third port 10 c is compared with the shape of the outlet portion of the first port 10 a or the fourth port 10 d. It has a flat shape whose vertical width is smaller than the horizontal width (that is, the aspect ratio (horizontal width / vertical width) is large). Thus, by making the confluence port 12 flat, the flow resistance can be increased and the flow rate of the exhaust gas flowing through the confluence port 12 is reduced as compared with the case where the confluence port 12 is not flat. The same effect as when the length of the pipe is increased can be obtained. The adjustment of the offset amount of the exhaust port 10 and the adjustment of the shape of the outlet portion of the merging port 12 can be performed in combination.

  As described above, instead of making the shape of the outlet portion of the merging port 12 flat, the outlet portion area of the merging port 12 is made smaller than the outlet portion area of the first port 10a or the fourth port 10d. However, the effect of reducing the flow rate of the exhaust gas is exhibited as in the case where the shape of the outlet portion is flat.

  A second embodiment of the cylinder head 1 according to the present invention will be described with reference to FIGS. Each of these drawings also represents the outer shape of the exhaust port 10 and the water chamber 11 formed in the cylinder head 1 (the shape of the core used when the cylinder head 1 is cast) as in the first embodiment. It is a thing. The cylinder head 1 incorporates a plurality of exhaust ports 10 connected to a plurality of cylinders 6, respectively. This engine is an in-line four-cylinder engine, and each cylinder 6 (first cylinder 6a, second cylinder 6b, third cylinder 6c, fourth cylinder 6d) has a first port 10a, a second port 10b, a third cylinder. The port 10c and the fourth port 10d are connected in the order in which the cylinders 6 are arranged.

  As shown in FIGS. 7 to 9, the exhaust ports 10 are gathered near the center in the arrangement direction of the plurality of cylinders 6 arranged in series (near the middle between the second cylinder 6b and the third cylinder 6c). The second port 10b and the third port 10c join together in the middle to form the joining port 12, while the first port 10a and the fourth port 10d do not join with the other exhaust ports 10 and are independent from each other. It is gathered as it is. In this gathering position, the merge port 12 is disposed above the first port 10a and the fourth port 10d.

  The water chamber 11 is disposed so as to surround the entire exhaust port 10 from the periphery. The water chamber 11 is composed of an upper water chamber 11a disposed on the upper side of the exhaust port 10 and a lower water chamber 11b disposed on the lower side. Cooling water is circulated in the water chamber 11 by a water pump. As a result, the exhaust gas flowing through each exhaust port 10 provided close to the water chamber 11 is cooled.

  For example, in an in-line four-cylinder engine, combustion occurs in the order of the first cylinder 6a, the third cylinder 6c, the fourth cylinder 6d, and the second cylinder 6b every time a crankshaft (not shown) rotates 180 degrees. That is, the second cylinder 6b and the third cylinder 6c are out of phase by 360 degrees in the rotation angle of the crankshaft, and are connected to the second port 10b connected to the second cylinder 6b and the third cylinder 6c. Even if the third ports 10c are merged, no exhaust interference occurs in the exhaust stroke. For this reason, problems such as residual exhaust gas in the cylinder 6 due to exhaust interference and occurrence of knocking when the compression ratio is high are avoided.

  As shown in FIG. 7, when the horizontal plane including the average center position in the vertical direction of the bent portion of each exhaust port 10 in the horizontal direction at the connection portion of the exhaust port 10 to each cylinder 6 is defined as the horizontal reference plane f. The merging port 12 is offset by Δdu upward from the horizontal reference plane f, whereas the first port 10a and the fourth port 10d are positioned within the horizontal reference plane f without being offset in the vertical direction. (Offset amount Δdl = 0).

  In the cylinder head 1 according to the second embodiment, the exhaust ports 10 are assembled near the middle between the second cylinder 6b and the third cylinder 6c. In this case, the horizontal distance from each cylinder 6 to the collection position is shorter in the second port 10b and the third port 10c (merging port 12) than in the first port 10a and the fourth port 10d. Therefore, as described above, some exhaust ports (here, the merge port 12 (second port 10b and third port 10c)) of the plurality of exhaust ports 10 are offset upward by Δdu from the horizontal reference plane f. By setting the other exhaust ports (here, the first port 10a and the fourth port 10d) to the same height as the horizontal reference plane f (offset amount Δdl = 0), based on the offset amount Δdu of the merging port 12 The port lengths of the second port 10b and the third port 10c constituting the merging port 12 in the cylinder head 1 can be relatively extended as compared with the case where no offset is performed.

  As described in the case of the first embodiment, the catalyst device 7 is often connected to the lower side of the cylinder head 1 (see FIG. 6). When the port 10b and the third port 10c) are offset upward, the length of the exhaust gas pipe 8 connecting the cylinder head 1 and the catalyst device 7 outside the cylinder head 1 is not offset. It can be relatively extended in comparison.

  The length of the exhaust gas pipe connected to the second cylinder 6b and the third cylinder 6c (the second port 10b or the third port 10c (merging port 12)) and the exhaust gas pipe line 8 inside and outside the cylinder head 1 The length of the exhaust gas pipe and the length of the exhaust gas pipe connected to the first cylinder 6a and the fourth cylinder 6d (the first port 10a or the fourth port 10d and the exhaust gas) The total length of the gas pipes 8) can be made similar. In this way, the flow of exhaust gas from the engine to the catalyst device 7 becomes smooth, and exhaust interference can be surely prevented, and various types of sensors such as an air-fuel ratio sensor and an oxygen concentration sensor provided in the catalyst device 7 can be obtained. The sensitivity of the sensor 9 can be improved.

  A bulging portion 11c bulging upward is formed at the center of the upper water chamber 11a. Junction port 12 is arranged so as to fit under the bulging portion 11c. A water channel 13 is formed inside a partition wall (not shown) that divides the first port 10 a, the fourth port 10 d, and the merging port 12. As shown in FIG. 7A, the water channel 13 has a T-shape when viewed from the front. As shown in FIG. 10 (a), this water channel 13 uses the drill D to aim at the space between the merging port 12 and the first port 10a and the fourth port 10d, from the horizontal direction, the upper water chamber 11a. A horizontal water channel 13a is drilled in the partition wall so as to penetrate, and further, the horizontal water channel 13a is penetrated through the lower water chamber 11b from the lower side to the upper side aiming between the first port 10a and the fourth port 10d. It is formed by perforating the reaching vertical water channel 13b.

  Thus, by making the shape of the water channel 13 T-shaped (connecting the horizontal water channel 13a and the vertical water channel 13b), the cooling water flowing through the horizontal water channel 13a is caused to flow upward or downward via the vertical water channel 13b. The vertical movement of cooling water is promoted. Then, the cooling water in the lower water chamber 11b where the cooling water temperature is likely to rise due to the influence of the adjacent combustion chambers and the cooling water in the upper water chamber 11a where the cooling water temperature is relatively low are agitated. The cooling efficiency can be further increased.

  By efficiently cooling the exhaust port 10 and lowering the temperature of the exhaust gas, it is possible to avoid the deterioration of the cylinder head 1 due to thermal distortion. Further, it is not necessary to make the air-fuel ratio rich in the high load region in order to lower the combustion temperature, and fuel efficiency can be improved. Furthermore, since the fuel can be burned at the stoichiometric air-fuel ratio, high purification efficiency of exhaust gas by the three-way catalyst can be ensured.

  In addition, formation of the water channel 13 by a drill process is only what illustrated the formation method, for example, you may form the water channel 13 by other methods, such as providing a core.

  Although not shown in FIG. 7, an air vent hole is formed at the top of the bulging portion 11c of the upper water chamber 11a, and an air vent pipe for discharging the air accumulated in the bulging portion 11c is connected to the air vent hole. It is good also as a structure. In this way, even if air is mixed into the upper water chamber 11a, this air can be quickly discharged so that the bulging portion 11c is completely filled with cooling water. The high cooling efficiency of (especially the merge port 12) can be maintained.

  Further, as shown in FIGS. 10B to 10D, a partition wall between the upper water chamber 11a and the lower water chamber 11b (for example, a baseboard for holding the core of the lower water chamber 11b, exhaust gas) Between the ports, between the cylinders, between the exhaust valves, the end of the water chamber, etc., through holes are formed using a drill D. Thus, by forming the through hole and connecting the upper water chamber 11a and the lower water chamber 11b, the circulation of the cooling water in the water chamber 11 can be enhanced, and the cooling efficiency can be further improved. A sealing process such as fitting a faucet is performed on the opening of the perforation formed by the drill D so that the cooling water in the water chamber 11 does not leak. The positions of the through holes shown in FIGS. 10B to 10D are merely examples, and the shapes of the upper water chamber 11a and the lower water chamber 11b, the arrangement of the exhaust ports 10 and the exhaust gas flowing through the exhaust ports 10 are illustrated. It can be determined appropriately in consideration of the temperature of the gas.

  The above-described embodiment is merely an example, and as long as the problem of the present invention of further reducing the size can be solved while ensuring the smooth exhaust characteristics of the cylinder head 1 incorporating the exhaust manifold, its configuration Changes can be made to the elements as appropriate.

  For example, regarding which exhaust port 10 of the plurality of exhaust ports 10 merge to form the merging port 12 or the offset amount of each exhaust port 10 (merging port 12), etc. However, the position can be determined appropriately in consideration of the arrangement configuration of each exhaust port 10 and the positional relationship between the cylinder head 1 and other devices such as the catalyst device 7.

  Moreover, although not shown in figure, as long as the compactness of an exhaust system is not impaired, the some exhaust port 10 (merging port 12) can also be set as the structure which overlapped 3 steps or more in the up-down direction. Furthermore, the number of cylinders of the engine is not limited to four, and the present invention can be applied to an engine having an arbitrary number of three or more cylinders in which the exhaust ports 10 can be arranged so as to overlap each other.

DESCRIPTION OF SYMBOLS 1 Cylinder head 2 Cylinder block 3 Cylinder 4 Piston 5 Intake port 6 Cylinder 7 Catalytic device 8 Exhaust gas conduit 9 Sensor 10 Exhaust port 10a First port 10b Second port 10c Third port 10d Fourth port 11 Water chamber 11a Upper water Chamber 11b Lower water chamber 11c Swelling portion 12 Merge port 13 Water channel f Horizontal reference plane D Drill

Claims (4)

In an engine cylinder head with a plurality of exhaust ports connected to a plurality of cylinders,
The number of cylinders of the cylinders is 3 or more, and one exhaust port of the plurality of exhaust ports and another exhaust port merge to form a merge port, and this merge port includes the plurality of exhaust ports. An engine cylinder head, wherein the cylinder head is disposed so as to overlap vertically above another exhaust port different from the one exhaust port and the other exhaust port. When the number of cylinders is 4, and the exhaust ports connected to the cylinders are the first port, the second port, the third port, and the fourth port in the arrangement order, the merge port 2. The engine cylinder head according to claim 1, wherein the cylinder head is configured by merging the second port and the third port. The first port and the fourth port are arranged in parallel with each other, and are disposed below the merge port, and the merge port, the first port, and the fourth port are arranged from the gas flow direction of each port. 3. The engine cylinder head according to claim 2, wherein the engine cylinder head is partitioned by a T-shaped partition as viewed, and a cooling water channel along the T-shape is formed inside the partition. The aspect ratio of the horizontal direction with respect to the vertical direction of the cross section by the vertical plane with respect to the gas flow direction at the outlet portion of the merge port is larger than the aspect ratio of the cross section of the exhaust ports other than the exhaust ports constituting the merge port. The cylinder head for an engine according to any one of claims 1 to 3.

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