JP6591864B2 - Internal combustion engine - Google Patents

Description

  The present invention relates to an internal combustion engine for a vehicle or the like, and particularly has a feature in a distribution supply structure of an additive gas such as EGR gas or blow-by gas.

  For example, in an internal combustion engine for a vehicle, EGR gas that is part of exhaust gas is recirculated to an intake system for the purpose of promoting purification of the exhaust gas. Also, the blow-by gas blown into the crank chamber is widely returned to the intake system. Furthermore, the volatile fuel generated in the fuel tank is collected by a canister and supplied to the intake system.

These additive gases such as EGR gas are generally taken into the intake manifold, and as an example of a distribution structure in the intake manifold, in Patent Document 1, the branch pipe is greatly bent from the bottom to the top as viewed from the crank axis direction. In an intake manifold integrated with a surge tank, an example is disclosed in which a distribution passage extending long along the crank axis is provided on the upper side of the intake manifold, and a discharge port is opened on the upper surface of the end portion near the outlet of each branch pipe.

  On the other hand, in Patent Document 2, in an intake manifold of an internal combustion engine in which cylinders are upright, a distribution passage that is long in the crank axis direction is provided below the group of branch pipes and discharged to the lower surface of the end part of each branch pipe. Opening the outlet is disclosed.

  Further, Patent Document 3 discloses that a purge gas is taken into a surge tank, mixed with fresh air in the surge tank, and distributed to each branch pipe of the intake manifold, and a connecting flange and a cover constituting the end portion of the intake manifold. It is described that an EGR passage that is long in the direction of the cylinder is formed on the mating surface with the flange, and EGR gas is distributed from the EGR passage to each branch pipe.

JP 2012-219626 A JP 2012-087732 A JP 2010-265871 A

  Although Patent Document 1 is superior in terms of suppressing contamination of the intake passage because the additive gas is discharged toward the end of the branch pipe, the distribution passage is disposed on the intake manifold, so that the height of the internal combustion engine is increased. However, there is a concern about the problem of lack of compactness.

  Particularly, in the slant type internal combustion engine in which the cylinder is inclined with respect to the vertical line, the height of the arrangement space of the internal combustion engine is often limited. Therefore, in the configuration of Patent Document 1, a space for providing the distribution passage is secured. Expected to be impossible. In addition, when the additive gas is EGR gas, an EGR valve is often connected to the distribution passage. However, if the distribution passage is arranged directly above the intake manifold as in Patent Document 1, the EGR valve is also connected to the intake manifold. Since it is located directly above, it can be said that the difficulty of securing the space appears remarkably.

On the other hand, in Patent Document 2, since the distribution passage is arranged below the group of branch pipes, it is possible to prevent the height of the internal combustion engine from increasing, but the inlet of the distribution passage is exposed to the side of the intake manifold. Therefore, EGR valve will be placed next to the intake manifold, Then, will be exhibiting a tendency EGR device becomes long in the crank axial direction as a whole, therefore, there is a possibility that the compactness is not always sufficient.

  Furthermore, the EGR gas passage has a problem of condensed water generated in the middle of the piping due to a temperature drop of the residual gas after the engine is stopped or a gas temperature drop by the EGR cooler. In other words, the generation of condensed water should be avoided as much as possible from the viewpoint of preventing corrosion of the pipeline, and also from the viewpoint of preventing problems caused by the condensed water flowing into the cylinder during engine start-up and operation. Although it should be avoided, in Patent Document 2, since the discharge port is slightly higher than the distribution passage, the condensed water tends to accumulate, and there is a concern that it is difficult to eliminate the adverse effects of the condensed water.

Regarding Patent Document 3, first, regarding purge gas, when purge gas is introduced into a surge tank as in Patent Document 3, if the position of the purge gas inlet is not appropriate, the purge gast and intake air ( fresh air ) are not sufficiently mixed. As a result, the purge gas may not be evenly distributed to each cylinder.

  On the other hand, regarding EGR gas, Patent Document 3 is superior in terms of compactness in the thickness direction because the EGR passage is formed in the thickness of the intake manifold, but the EGR gas inlet is formed of a branch pipe. Since the EGR valve must be disposed outside the row of branch pipes because it is located on the outside facing the parallel direction, the intake manifold tends to spread in the direction of the branch pipes as a whole with the EGR device. In this respect, it can be said that the compactness is inferior. Further, when the EGR passage is provided on the mating surface of the members constituting the intake manifold, there is a problem that it is difficult to increase the recirculation amount of the EGR gas because it is difficult to increase the cross-sectional area of the EGR passage.

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

The present invention is as follows: “ A cylinder head in which a plurality of intake ports are formed side by side in the crank axis direction ; a plurality of branch pipes corresponding to the plurality of intake ports; and a trough located between adjacent branch pipes. It has an intake manifold made of synthetic resin arranged side by side ,
Wherein the intake manifold, new with the discharge port of the gas is not additive gas are formed so as to open at the end or each intake port before Symbol respective branch pipes, the respective discharge ports of the additional gas from one inlet A distribution passage is formed for distribution toward
This is the basic configuration.

And in the above basic configuration,
"While the inflow port is located at the upstream side of the discharge port at the position where the valleys exist on both sides of the inflow port,
The distribution passage has a first passage branched from the inflow port and extending in a direction crossing the branch pipe, and a second passage bent from an end of the first passage and going downstream in the valley portion. It is formed in a tournament shape with multiple branches as a whole. ''
The configuration is added.

  In the present invention, the end portion of the branch pipe constituting the intake manifold is configured to bend downward from the lateral posture as viewed from the crank axis direction, and the discharge port is opened from the inside of the curve toward the inside of the branch pipe. Is preferred. Moreover, it is preferable that the distribution passage is directed downward from the inlet to the outlet.

In the present invention, since the discharge port is located at the end of the branch pipe or at the intake port, the distribution performance of the additive gas is excellent. Further, even when the additive gas is EGR gas or blow-by gas, contamination of the inner surface of the intake manifold can be significantly suppressed. Further, since the distribution passage has a tournament shape, the additive gas can be evenly distributed to the discharge ports.

In addition, when the additive gas is EGR gas, there is an advantage with respect to condensed water. That is, first, since the inlet of the additive gas is located at the branch pipe group, the length of the conduit leading the EGR gas from the exhaust system can be shortened as much as possible. Can be suppressed. In addition, since the discharge port is located at the end of the branch pipe or at the intake port, the heat generated in the cylinder is easily transferred to the EGR gas, thereby evaporating the moisture contained in the EGR gas. It can be said that the generation of condensed water can be suppressed.

  When the end portion of the branch pipe is curved, the intake air tends to flow strongly along the outside of the curve. However, in the present invention, when the discharge port is provided inside the curve, the additive gas is sucked into the strong flow of the intake air. Since the tendency is exhibited, there is an advantage that the mixing property between the intake air and the additive gas is excellent.

  Furthermore, in the present invention, since the inlet and outlet of the distribution passage are divided into the front side and the back side of the branch pipe group, when the additive gas distribution path is arranged on the branch pipe group, In comparison, the height of the intake manifold can be reduced. Further, the distribution passage and the inlet do not protrude in the crank axis direction. By these points, the intake manifold with the distribution passage for the additive gas can be made compact as a whole. As a result, the present invention can be easily applied to a slant type internal combustion engine in which the height of the installation space is often limited.

1 is a front view of an internal combustion engine according to a first embodiment. It is a perspective view of an intake manifold. It is a top view of an intake manifold. It is a bottom view of an intake manifold. FIG. 5 is a cross-sectional view taken along the line V-V in FIG. It is a schematic diagram of the 1st reference example . It is a schematic diagram of the 2nd, 3rd reference example . It is a principal part schematic sectional drawing of the 4th reference example .

(1). Summary of the implementation forms will be described with reference to the embodiment of the present invention with reference to the drawings. In Figure 1-5 and displays the embodiment, first, an outline of an internal combustion engine according to the implementation embodiments.

  FIG. 1 is an overall front view of an internal combustion engine as viewed from the crank axis direction. As shown in FIG. 1, the internal combustion engine includes a cylinder block 1 and a cylinder head 2 as main elements of the engine body. A head cover 3 is fixed to the top surface of the head 2, while an oil pan 5 is fixed to the bottom surface of the cylinder block 1 via a crankcase block 4. The crankshaft is indicated by reference numeral 6.

  The internal combustion engine of the present embodiment is a slant type in which the cylinder bore axis 7 is largely tilted to the horizontal side, and the cylinder head 2 has the intake side surface 8a facing up and the exhaust side surface 8b facing down. The intake side surface 8a is substantially horizontal, and the intake manifold 9 is fixed to the intake side surface 8a. An exhaust manifold is fixed to the exhaust side surface 8b, but this is not shown.

  As shown in FIGS. 2 to 4, the intake manifold 9 has a surge tank portion 10 and four branch pipes 11 to 14 branched therefrom. Therefore, the internal combustion engine of this embodiment has four cylinders, and the intake manifold 9 is a surge tank integrated type. The branch pipes 11 to 14 are arranged in the crank axis direction (cylinder row direction), and in order from one end of the arrangement, the first branch pipe 11, the second branch pipe 12, the third branch pipe 13, and the fourth branch pipe 14 I will call it.

  As shown in FIGS. 1, 2, and 5 (A), the branch pipes 11 to 14 are approximately half horizontal in the upstream side, and then rise in a posture inclined obliquely upward, and then The horizontal posture is maintained for a certain length, and the end faces downward. Therefore, the intake manifold 9 has four parts in order from the upstream side: a lower horizontal portion 16, an inclined rising portion 17, an upper horizontal portion 18, and a downward end portion 19. Adjacent parts are smoothly continuous. Therefore, a curved portion 20 is formed by the upper horizontal portion 18 and the downward end portion 19.

  As shown in FIG. 2 and FIG. 3, the branch pipes 11 to 14 are in close contact with each other at the lower horizontal portion 16 and are in a bundled state, and the start ends thereof are open inside the surge tank portion 10. . The surge tank portion 10 is provided with an intake inlet 10a to which a throttle body (not shown) is attached. The intake inlet 10a is opened obliquely upward. The branch pipes 11 to 14 are parallel to each other at the upper horizontal portion 18, and are also substantially parallel to the downstream end portion and the downward end portion 19 of the upper horizontal portion 18. Therefore, the inclined rising portion 17 and the corresponding portion on the front side of the upper horizontal portion 18 are spread and deformed in the crank axis direction.

(2). EGR gas distribution passage In this embodiment, EGR gas is added to the intake manifold 9 as an example of the additive gas. EGR gas is sent from the engine exhaust system through the EGR pipe 21, and an EGR gas inlet 22 to which the end of the EGR pipe 21 is connected is provided on the front side of the end of the inclined rising portion 17. The EGR gas inlet 22 is provided with a joint flange 23 for connecting the EGR pipe 21. The joint flange 23 is generally long in the vertical direction, and is provided with bolt insertion holes at the upper end and the lower end.

In addition, although the arrangement | positioning position of the EGR gas inflow port 22 has become the location of the 3rd branch pipe 13 in embodiment, it can be arbitrarily set as needed. For example, it may be arranged between the second branch pipe 12 and the third branch pipe 13.

  As shown in FIGS. 2, 3, and 5, an EGR gas discharge port 24 is opened at an inner portion facing the cylinder head 2 when viewed from the crank axis direction in the downward end portions 19 of the branch pipes 11 to 14. is doing. Therefore, the intake manifold 9 is provided with an EGR gas distribution passage 25 for distributing EGR gas from the EGR gas inlet 22 to the four EGR gas outlets 24.

As shown in FIGS. 2 and 3, the EGR gas distribution passage 25 is in the crank axis direction (in a direction crossing the branch pipes 12, 13 ) on the outer side (upper side) of the second branch pipe 12 and the third branch pipe 13. One extending first passage 25a, two second passages 25b that bend from both front and rear ends of the first passage 25a and extend in the downstream direction, and a third passage 25c branched substantially in the front-rear direction from the end of the second passage 25b And a fourth passage 25d extending downstream from the end of the third passage 25c, and the end of the fourth passage 25d is an EGR gas discharge port 24.

Second passage 25b is arranged between the first branch pipe 11 and the second branch pipe 12, and, positioned and in valleys outside (upper side) between the third branch pipe 13 and the fourth branch pipe 14 And since each branch pipe 11-14 has expanded the mutual space | interval, the 2nd 2nd channel | path 25b also has the mutual space | interval widening toward the termination | terminus (toward downstream).

  The first passage 25 a and the second passage 25 b are exposed on the upper side of the intake manifold 9, but the third passage 25 c and the fourth passage 25 d are in a state of being hidden below the intake manifold 9. Accordingly, the EGR gas distribution passage 25 penetrates the intake manifold 9 from the top to the bottom (from the front side to the back side) between the adjacent branch pipes 11 to 14.

  The third passage 25c is inclined so as to approach the EGR gas discharge port 24 toward the end in plan view, and the connection portion between the third passage 25c and the fourth passage 25d is provided in the buffer space 26 having a large volume. It has become. The buffer space 26 and the fourth passage 25 c are located directly below the center line of each upper horizontal portion 18. Accordingly, the EGR gas discharge port 24 is also opened so as to be directed to the center line of the downward end portion 19. As clearly shown in FIG. 5B, the fourth passage 25d has a tapered shape in which a cross-sectional area is widened toward the tip. For this reason, EGR gas is ejected into the intake passage while diffusing.

The intake manifold 9 of the present embodiment is a molded product of synthetic resin . Basically, the two upper and lower main parts are superposed and then welded by high-frequency vibration or ultrasonic vibration. For this reason, the flange 23 for welding protrudes from both front and rear ends. However, since the first passage 25a and the second passage 25b of the EGR gas distribution passage 25 cannot be formed only by joining two main parts, auxiliary parts are welded to the main parts.

(3). Conclusion The present embodiment of implementation form, EGR gas flowing in the EGR gas inlet 22 is branched from the branch to the two first passages 25a, two further at the end of the second passage 25b To do. That is, the EGR gas distribution passage 25 has a tournament shape. Therefore, the EGR gas can be evenly distributed to the four EGR gas discharge ports 24.

And the 2nd channel | path 25b has entered into the groove-shaped part ( valley part) between the adjacent branch pipes 11-14, and the 3rd channel | path 25c and the 4th channel | path 25d are the downward direction of the branch pipes 11-14. Therefore, the exposure of the EGR gas distribution passage 25 on the intake manifold 9 can be suppressed. For this reason, the intake manifold 9 can be made compact as a whole.

In particular, in the present embodiment, since the EGR gas inlet 22 including the joint flange 23 is disposed in the inclined rising portion 17, most of the joint flange 23 and the front part of the EGR gas inlet 22 are placed upward. Since it can be located below the horizontal part 18, compactization can be further promoted. That is, in this embodiment, since the branch pipes 11 to 14 have the inclined rising portions 17, a recess 27 (see FIG. 5A) with an upward opening is formed above the intake manifold 9. and that although, from the particular can be effectively utilized the recess 27 as an arrangement place of the joint flange 23, to promote compactness of the intake manifold 9, and by extension, it can be as low as possible the height of the internal combustion engine.

  Furthermore, since the connection surface 23a of the joint flange 23 is inclined in the same manner as the inclined rising portion 17, the height of the flange provided at the end of the EGR pipe 21 can be reduced. This can further contribute to the suppression of the height of the internal combustion engine. It is also possible to dispose the entire joint flange 23 below the upper horizontal portion 18.

  When the terminal portions of the branch pipes 11 to 14 are configured in the curved portion 20 as in the present embodiment, the intake air is strongly along the outer surface 20a of the curved portion 20 as indicated by an arrow 29 in FIG. Presents a tendency to flow. And since the EGR gas discharge port 24 is opened to the inner surface 20b side of the bending portion 20, the EGR gas tends to be drawn by the suction action of a strong flow of intake air. Thereby, supply of EGR gas is performed smoothly, and the mixing property of intake air and EGR gas can be improved.

  In addition, since the EGR gas discharge port 24 is provided just before the opening edge of the downward terminal portion 19, the inner surfaces of the branch pipes 11 to 14 are hardly contaminated with EGR gas. In particular, as described above, since the intake air strongly flows on the outer surface 20a of the curved portion 20, the ejected EGR gas is mixed with the intake air and does not reach the outer surface 20a, and is sent to the intake port. Therefore, it can be said that the inner surface of the intake manifold 9 is hardly contaminated with EGR gas.

  Further, since the EGR gas discharge port 24 is located at the terminal end of each branch pipe 11-14, each branch pipe 11-14 can take a long portion where only the intake air flows. Can be increased. Therefore, it is possible to contribute to an improvement in torque in the low and medium speed range.

  If the connection part of the 3rd channel | path 25c and the 4th channel | path 25d is formed in the buffer space 26 like embodiment, there exists an advantage which can discharge EGR gas smoothly, suppressing the flow resistance of EGR gas. In addition, since each cylinder burns in order, the flow of intake air in each branch pipe 11 to 14 also fluctuates. However, if the buffer space 26 is provided, fluctuations in the intake air (negative pressure fluctuations) in each branch pipe 11 to 14 occur. There is also an advantage that the EGR gas can be stably discharged to the branch pipes 11 to 14 while being prevented from spreading to the EGR gas distribution passage 25.

  As shown in FIG. 5, the EGR gas distribution passage 25 has a height that decreases toward the EGR gas discharge port 24 as a whole. For this reason, condensed water does not accumulate in the EGR gas distribution passage 25.

(4) Reference Example FIG. 6 shows a first reference example . That is, this reference example is a specific example of the EGR gas distribution passage 25. First, one main passage 25e extends from the EGR gas inlet 22 toward the downstream side on the upper side of the intake manifold 9.

  As one aspect, four branch passages 25f are branched from the end of the main passage 25e toward the four EGR gas discharge ports 24. The branch passage 25 f is located below the intake manifold 9. Accordingly, the EGR gas distribution passage 25 penetrates from the top to the bottom between the second branch pipe 12 and the third branch pipe 23 at the end of the main passage 25e. The dotted line in the figure indicates that it is located below the intake manifold 9.

In another aspect , an intermediate passage 25g is connected to the end of the main passage 25e so as to cross the group of the branch pipes 11 to 14, and four branch passages 25f are branched from the intermediate passage 25g. Therefore, the main passage 25e and the intermediate passage 25g are connected in a T shape. In Figure 6, but are displayed in a state in which a EGR gas discharge ports 24 at the end of the branch passage 25f, as in the implementation form, a fourth passage 25d changes the end of each branch pipe 11-14 It is preferable to provide the EGR gas discharge port 24 at the end of the fourth passage 25d.

FIG. 7A shows a second reference example applied to an internal combustion engine in which the cylinder bore axis 7 is in a vertical posture. In this reference example , the intake side surface of the cylinder head 2 is inclined so as to approach the cylinder bore axis 7 as it goes upward as viewed from the crank axis direction, and at least the terminal portion of each branch pipe of the intake manifold 9 is inclined. A downward portion 30 is formed.

  Then, an EGR gas inlet 22 is provided on the upper side of the intake manifold 9, and the EGR gas distribution passage 25 is penetrated downward from between the adjacent branch pipes in the intake manifold 9, so that branch passages 25f to the respective branch pipes. Is provided on the lower surface side of the intake manifold 9. The branch passage 25f is inclined so that the height decreases toward the EGR gas discharge port 24. For this reason, condensed water does not accumulate in the EGR gas distribution passage 25.

  The start end portion of the branch pipe of the intake manifold 9 may be bent upward as shown by a solid line, or may be bent downward and provided with a surge tank portion 10 at its lower end as shown by a one-dot chain line.

The third reference example shown in FIG. 7B is applied to an internal combustion engine in which the cylinder bore axis 7 is horizontal. In this embodiment, the branch pipe of the intake manifold 9 is curved downward from a substantially horizontal posture, and the branch passage 25 f of the EGR gas distribution passage 25 is connected to the downward portion 30.

  7A and 7B, the EGR gas distribution passage 25 penetrates the branch pipe of the intake manifold 9 from the top to the bottom, and the EGR gas discharge port 24 has a cylinder bore across the intake manifold 9. Located on the side close to

In the above embodiment and reference example , the EGR gas discharge port 24 is provided in the branch pipe of the intake manifold 9, but in the fourth reference example shown in FIG. 8, the EGR gas discharge port 24 is provided in the cylinder head 2. It is provided and opened to the intake port 31. Therefore, the cylinder head 2 is formed with a communication passage 32 that opens to the intake side surface 8 a for each intake port 31, and the branch passage 25 f of the EGR gas distribution passage 25 formed in the intake manifold 9 is connected to the communication passage 32. It is connected to the.

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

DESCRIPTION OF SYMBOLS 1 Cylinder block 2 Cylinder head 6 Crankshaft 7 Cylinder bore axis 8a Cylinder head intake side 9 Intake manifold 10 Surge tank part 11-14 Branch pipe 16 Lower horizontal part 17 Inclined rising part 18 Upper horizontal part 19 Down end part DESCRIPTION OF SYMBOLS 20 Curve part 21 EGR pipe 22 EGR gas inflow port 24 EGR gas discharge port 25 EGR gas distribution channel 25a 1st channel | path 25b 2nd channel | path 25c 3rd channel | path 25d 4th channel | path 26 Buffer space

Claims (1)

Synthesis plurality of intake ports are arranged and a cylinder head formed by arranging the crankshaft axis direction, a valley portion positioned between the plurality of branch pipes and neighboring branches tubes corresponding to the plurality of intake ports side by side With a plastic intake manifold ,
Wherein the intake manifold, new with the discharge port of the gas is not additive gas are formed so as to open at the end or each intake port before Symbol respective branch pipes, the respective discharge ports of the additional gas from one inlet A distribution passage that is distributed toward the
While the inflow port is disposed on the upstream side of the discharge port at a position where the valley is present on both sides of the inflow port,
The distribution passage has a first passage branched from the inflow port and extending in a direction crossing the branch pipe, and a second passage bent from an end of the first passage and going downstream in the valley portion. And formed as a tournament having a plurality of branch portions as a whole,
Internal combustion engine.

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