JP2017082740A - Internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine, with added gas such as EGR gas supplied to an intake manifold, which prevents condensate water from being generated in the intake manifold or accumulated in piping of the added gas and downsizes the intake manifold in whole.SOLUTION: An intake manifold 9 comprises: inclined rising sections 17; upper horizontal sections 18; and downward end sections 19. Each end section has a bent section 20. An EGR gas inflow port 22 is provided at an upper side of the inclined rising sections 17. An EGR gas distribution passage 25 penetrates through branch pipes 11 to 14 arranged next to each other and is divided into branches toward respective branch pipes 11 to 14. EGR gas discharge ports 24 have openings on inner surfaces 20b of the bent sections 20. Because the EGR gas distribution passage 25 can be arranged within a thickness of the intake manifold 9, the intake manifold 9 can be downsized in whole.SELECTED DRAWING: Figure 5

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.

  This additive gas is generally taken into the intake manifold, and as an example of a distribution structure in the intake manifold, in Patent Document 1, a surge tank integrated type in which the branch pipe is bent largely from the bottom as viewed from the crank axis direction. In the intake manifold, there is disclosed an example 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, the EGR valve is disposed beside the intake manifold, and as a result, the EGR device tends to become longer in the crank axis direction as a whole, and therefore there is a possibility that the compactness is not necessarily 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 the purge gas, if the purge gas is introduced into the surge tank as in Patent Document 3, the purge gas inlet and the intake air (new) are not sufficiently mixed unless the position of the purge gas inlet is appropriate. Thus, the purge gas may not be evenly distributed to the cylinders.

  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 includes a cylinder head in which a plurality of intake ports are arranged in the crank axis direction, and an intake manifold in which a plurality of branch pipes are arranged in correspondence with the plurality of intake ports. The additive gas discharge port is not opened to the end of each branch pipe or each intake port, and the additive gas is distributed to each discharge port through a distribution passage after entering one inflow port. This is the basic configuration.

  The inlet of the additive gas is disposed on the side farther from the cylinder across the branch pipe group in the intake manifold when viewed from the crank axis direction, while each discharge port is viewed from the crank axis direction. The branch passages in the intake manifold are disposed on the side close to the cylinder, and the distribution passages pass between the adjacent branch pipes in the intake manifold before reaching the discharge ports. Yes.

  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 of the additive gas is formed on one side or both sides across the group of branch pipes, the distribution passage can increase the cross-sectional area without interfering with the branch pipe. For this reason, the present invention can be applied to an internal combustion engine in which the amount of recirculation of EGR gas is increased without any problem.

  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 easily reaches the EGR gas, so that the moisture contained in the EGR gas can be reduced. It can be said that evaporation is promoted and 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 modification of 1st Embodiment. It is a schematic diagram of 2nd, 3rd embodiment. It is a principal part schematic sectional drawing of 4th Embodiment.

(1). Outline of First Embodiment Next, an embodiment of the present invention will be described with reference to the drawings. 1 to 5 show the first embodiment (main embodiment). First, an outline of the internal combustion engine according to the first embodiment will be described.

  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, 5 (A), the branch pipes 11 to 14 are approximately half the length of the upstream side in a posture that is nearly horizontal, and then stand up in a posture inclined obliquely upward, and then The horizontal position 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. For this reason, 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. Each of the branch pipes 11 to 14 is parallel in the upper horizontal portion 18, and is 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.

  The arrangement position of the EGR gas inlet 22 can be arbitrarily set as necessary. 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. 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 includes a first passage 25 a extending in the crank axis direction on the outer side (upper side) of the second branch pipe 12 and the third branch pipe 13, Two second passages 25b that are bent from both front and rear ends of the one passage 25a and extend in the downstream direction, a third passage 25c that branches from the end of the second passage 25b substantially in the front-rear direction, and downstream from the end of the third passage 25c The fourth passage 25d extends to the EGR gas discharge port 24 at the end thereof.

  The second passage 25b is located between the first branch pipe 11 and the second branch pipe 12, and between the third branch pipe 13 and the fourth branch pipe 14, and on the outer side (upper side). Since the branch pipes 11 to 14 increase the distance between each other, the distance between the two second passages 25b also increases toward the end (toward the downstream side).

  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 resin molded product. 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 EGR gas distribution passage 25 cannot be formed only by joining two main parts, auxiliary parts are welded to the main parts.

(3) Summary of the first embodiment In this embodiment, the EGR gas that has flowed into the EGR gas inlet 22 branches into two first passages 25a, and then is further divided into two at the end of the second passage 25b. Branch. 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 (or valley-shaped part) between the adjacent branch pipes 11-14, and the 3rd channel | path 25c and the 4th channel | path 25d are the branch pipes 11-14. Therefore, it is possible to suppress the EGR gas distribution passage 25 from being exposed on the intake manifold 9. 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. However, since the recess 27 can be effectively used as a place where the joint flange 23 is disposed, the intake manifold 9 can be made compact, and the height of the internal combustion engine can be reduced as much as possible.

  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 intake air (fluctuations in negative pressure) 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). Modification / Other Embodiments FIG. 6 shows a modification of the first embodiment. That is, this modification is a specific example of the EGR gas distribution passage 25, and first, one main passage 25 e extends from the EGR gas inlet 22 toward the downstream side above 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.

  As another aspect, an intermediate passage 25g having a posture across the group of the branch pipes 11 to 14 is connected to the end of the main passage 25e, 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 FIG. 6, the EGR gas discharge port 24 is provided at the end of the branch passage 25f. However, as in the first embodiment, the end portion of each branch pipe 11-14 and the modified fourth passage 25d are shown. It is preferable to provide the EGR gas discharge port 24 with the end of the fourth passage 25d.

  FIG. 7A shows a second embodiment applied to an internal combustion engine in which the cylinder bore axis 7 is in a vertical posture. In this embodiment, 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 embodiment 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-described embodiment, the EGR gas discharge port 24 is provided in the branch pipe of the intake manifold 9. However, in the fourth embodiment shown in FIG. 8, the EGR gas discharge port 24 is provided in the cylinder head 2. The port 31 is opened. 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.

  Also in the fourth embodiment, the EGR gas distribution passage 25 and the communication passage 32 are inclined downward as a whole. For this reason, condensed water does not accumulate. Although the above embodiment is applied to distribution of EGR gas, the present invention can also be applied to distribution of blow-by gas, distribution of fuel gas sent from a canister, and the like.

  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)

A cylinder head in which a plurality of intake ports are arranged side by side in the crankshaft direction, and an intake manifold in which a plurality of branch pipes are arranged in line corresponding to the plurality of intake ports are provided. A discharge port is open to the terminal end of each branch pipe or each intake port, and the additive gas is distributed to each discharge port through a distribution passage after entering one inflow port. There,
The inlet of the additive gas is disposed on a side farther from the cylinder across a group of branch pipes in the intake manifold as viewed from the crank axis direction,
Each of the discharge ports is disposed on a side closer to the cylinder across a group of branch pipes in the intake manifold as viewed from the crank axis direction,
The distribution passage reaches between the discharge ports after passing between adjacent branch pipes in the intake manifold.
Internal combustion engine.

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