JP6591791B2 - Internal combustion engine for vehicles - Google Patents

Description

  The present invention relates to an internal combustion engine mounted on a vehicle.

  An internal combustion engine for a vehicle is provided with an exhaust purification device such as a three-way catalyst, a lean NOx catalyst, or a DPF (diesel particulate filter) in order to purify exhaust gas. Further, recent internal combustion engines for vehicles include an exhaust gas recirculation device (hereinafter referred to as an EGR device) that recirculates a part of the exhaust gas to the intake system as EGR gas for the purpose of promoting exhaust gas purification and improving fuel efficiency. .

  In this case, the position of the exhaust gas purification device and the piping structure of the exhaust gas recirculation pipe are various. Looking at the position of the exhaust gas purification device, there are cases where the exhaust gas purification device is integrated with the exhaust manifold and in the middle of the exhaust pipe. There are cases where an exhaust purification device is provided and cases where both configurations are provided. Further, when looking at the relationship between the exhaust gas recirculation pipe and the exhaust gas purification apparatus, the exhaust gas recirculation pipe (EGR pipe) is connected to the upstream side of the exhaust gas purification apparatus, and the exhaust gas recirculation pipe is connected to the downstream side of the exhaust gas purification apparatus. In order to ensure the cleanliness of the engine, it is preferable to recirculate the exhaust gas purified by the exhaust purification device.

From the standpoint of vibration countermeasures, when the exhaust gas purification device is integrated with the exhaust manifold, the exhaust gas recirculation pipe is incorporated in the vibration system of the engine body together with the exhaust manifold. However, if the exhaust gas purification device is provided in the middle of the exhaust pipe, the vibration of the engine and the body of the vehicle body on which the exhaust pipe is suspended are not affected. Since both the vibration and the vibration are spread, if the exhaust gas recirculation pipe is provided, the vibration of the engine and the vibration of the vehicle body are also spread to the exhaust gas recirculation pipe. For this reason, if both ends of the exhaust gas recirculation pipe are fixed by welding or the like, high stress acts on the exhaust gas recirculation pipe or the exhaust pipe, and in some cases , the exhaust gas recirculation pipe or the exhaust pipe may be damaged. is there.

  With respect to this point, in Patent Document 1, an exhaust purification device is connected to the upstream portion of the exhaust pipe connected to the exhaust manifold with a spherical joint so as to absorb both the vibration of the engine body and the vibration of the vehicle body. In the configuration, an EGR gas relay space is formed in the spherical joint, and the exhaust gas recirculation pipe for recirculating the EGR gas taken out from the downstream side of the exhaust gas purification device is separated into the first and second tubes. By connecting the tube to the relay joint of the spherical joint, the stress caused by the difference in the vibration system is prevented from acting on the exhaust gas recirculation pipe.

  Further, in Patent Document 2, in the configuration in which the outlet of the exhaust manifold and the start end of the exhaust pipe are connected by a spherical joint, the middle part of the exhaust gas recirculation pipe connected to the downstream side of the exhaust purification device is near the spherical joint. It is disclosed that the stress generated by the difference between the vibration system of the engine main body and the vibration system of the vehicle body is absorbed by the flexible pipe by configuring the above part with a flexible pipe that can be bent and deformed. In Patent Document 2, the exhaust pipe and the exhaust manifold are joined by a flange, and a portion of the exhaust recirculation pipe that is downstream of the flexible pipe is joined by a flange for the exhaust pipe.

JP 2004-176553 A JP 2013-083230 A

  In both Patent Document 1 and Patent Document 2, since EGR gas is taken out from the downstream side of the exhaust purification device, there is an advantage that the cleanliness of the intake system members and cylinders can be maintained. The joint becomes a custom-made product and not only makes the structure complicated, but also there is a concern that the sealing performance may deteriorate during use and the exhaust gas may easily leak, and there is a concern about reliability.

  On the other hand, in the case of Patent Document 2, for example, a bellows tube can be considered as the flexible tube, but the exhaust gas does not always flow through the exhaust gas recirculation tube, and the exhaust gas may remain in the exhaust gas recirculation tube. Therefore, when the EGR gas stays after the engine is stopped or when the EGR device is not operating, the moisture contained in the exhaust gas may become condensed water and accumulate on the inner surface of the flexible pipe due to the temperature drop of the exhaust gas. Then, it cannot be said that there is no risk of corrosion and rust entering the combustion chamber, or causing a hole in the flexible tube.

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

The present invention is
“Intake section and exhaust section provided in the engine body, an exhaust pipe connected to the exhaust section, an exhaust purification apparatus interposed in the middle of the exhaust pipe, and the exhaust purification apparatus of the exhaust pipe An exhaust gas recirculation pipe branched from the downstream side and connected to the intake section;
The exhaust gas from the exhaust part to the intake part includes: a start side pipe connected to the exhaust part; a termination side pipe connected to the intake part; and the exhaust purification device and the termination side pipe Is divided into three or more pipelines with one or a plurality of intermediate pipelines located between the exhaust pipe and the start pipe, the terminal pipe and the suction pipe, and adjacent to each other. The pipes are connected so that they can rotate relative to each other. ''
This is the basic configuration.

And in the above basic configuration,
“ The connecting portion of each pipe line is composed of a spherical joint in which a hook-like part and a seal body are closely attached to each other by a spring and a pair of bolts , and each pipe line has a resistance. It is allowed to rotate in the vertical direction with
In addition, an angle formed by a line connecting a pair of bolts with respect to the horizontal in the spherical joint to which each pipe constituting the exhaust gas recirculation pipe is connected is a pair of in the spherical joint to which the start-end side pipe is connected. The line connecting the bolts is larger than the angle made to the horizontal. ''
The structure is added.

In the present invention, when each pipe line and the engine main body are viewed as members, the EGR gas recirculation path constitutes a link mechanism composed of at least four members. Therefore, depending on the difference between the vibration of the engine main body and the vibration of the vehicle body, When an external force to try to relative movement members each other acts, in particular therefore the vibration member adjacent to relative rotation is absorbed.

And in this invention, since it is possible to use a commercial item like a spherical joint as it is as a means to accept | permit the relative motion of an adjacent member, a structure is simple and can ensure high reliability. . Moreover, the use of spherical joints, without a pivot axis parallel to one another in the consolidated point, since the members to each other is relatively rotated smoothly, it is preferable to be improved freedom of design.

  Further, as in the embodiment, when the two pipes constituting the exhaust gas recirculation pipe are connected in a square shape, the angle of the square shape only changes regardless of the relative movement of the engine body and the exhaust purification device. Therefore, since the pipe lines do not stretch, smooth movement can be more reliably maintained. In addition, if the top of the square is directed to the exhaust pipe, there is an advantage that the whole can be made compact.

It is a plan view of the implementation forms. FIG. 2 is a side view taken along the line II-II in FIG. 1. FIG. 3 is an enlarged view of a main part of FIG. 2. It is the fragmentary sectional view which showed the structure of the spherical joint. It is a schematic diagram which shows a motion.

(1). Outline of Internal Combustion Engine Next, an embodiment of the present invention will be described with reference to the drawings. In the present application, front / rear / left / right words are used to specify the direction, but this is defined with the forward direction of the vehicle as the front (or the direction toward the driver). The direction indication is clearly shown in FIG. The front view is a state seen from a direction opposite to the forward direction of the vehicle. First, an outline of the internal combustion engine will be described with reference to FIGS.

  The internal combustion engine has an engine main body 1, and the engine main body 1 is disposed in the engine room in a vertically installed posture with the crankshaft oriented in the longitudinal direction of the vehicle. Although FIG. 1 is a plan view, the cylinder block 2, the cylinder head 3, the head cover 4, and the oil pan 5 that constitute the engine main body 1 are seen in a plan view. On the other hand, in the side view of FIG. 2, the head cover 4 and the oil pan 5 appear large, but the cylinder block 2 and the cylinder head 3 are only slightly visible.

  For this reason, the engine main body 1 of the present embodiment is largely slanted (tilted) to a state in which the cylinder is nearly horizontal in a front view. A transmission 2 a is arranged on the rear surface of the cylinder block 2. The illustrated one is an example, and the present invention can be applied to various types of internal combustion engines such as an internal combustion engine in which the cylinder is in a substantially vertical posture and a horizontal type in which the crank axis is in a left and right longitudinal posture.

  The internal combustion engine of the present embodiment has four cylinders, and therefore, four ignition device mounting holes 6 are arranged in the head cover 4 in the front-rear direction. In the present embodiment, the head cover 4 has the intake side facing upward and the exhaust side facing downward. Therefore, the intake manifold 7 is connected to the upper surface of the cylinder head 3.

  As shown in FIG. 1, a surge tank 9 having a throttle body 8 opened upward is connected to the intake manifold 7 as a member constituting the intake portion. An EGR cooler 10 is connected to the surge tank 9, and an EGR cooler is connected. 10 is provided with an EGR valve 11 at the end of the outlet side (the EGR cooler 10 may be omitted). As shown in FIG. 1, an air cleaner 8b is connected to the throttle body 8 via a hose 8a.

(2). Exhaust System / EGR Device As shown in FIG. 2, an exhaust manifold 12 is connected to the lower surface of the cylinder head 3. A collecting portion 12 a of the exhaust manifold 12 extends rearward, and an exhaust pipe 13 is connected to the collecting portion 12 a via a first spherical joint 14.

  The exhaust pipe 13 has an exhaust pipe first portion 17 in which a catalyst case (catalytic converter) 16 is integrated, and an exhaust pipe second portion 19 connected to the exhaust pipe first portion 17 by a flange 18. The silencer 20 is provided in the exhaust pipe second portion 19.

  The catalyst case 16 has a cone shape having a start end taper portion 16a and a terminal end taper portion 16b, and a three-way catalyst is built in a straight portion. Therefore, the exhaust purification device 21 is configured by the catalyst case 16 and the catalyst built therein.

  The branch pipe 22 is fixed to the terminal tapered portion 16b of the catalyst case 16 by welding or brazing, and the exhaust recirculation pipe first portion 23 is connected to the branch pipe 22 via the second spherical joint 24. An auxiliary pipe 25 is fixed to the EGR cooler 10 by welding or the like, and an exhaust recirculation pipe second portion 26 is connected to the auxiliary pipe 25 via a third spherical joint 27. Furthermore, the exhaust gas recirculation pipe first portion 23 and the exhaust gas recirculation pipe second portion 26 are connected via a fourth spherical joint 28. Therefore, the exhaust gas recirculation pipe 29 is constituted by the exhaust gas recirculation pipe first portion 23 and the exhaust gas recirculation pipe second portion 26. In other words, the exhaust gas recirculation pipe 29 is separated into the exhaust gas recirculation pipe first part 23 and the exhaust gas recirculation pipe second part 26.

  As shown in FIG. 1, the exhaust pipe first portion 17 of the exhaust pipe 13 has a rear portion bent in a substantially square shape, but extends substantially linearly in a side view. Further, as shown in FIG. 1, the branch pipe 22 is bent in a substantially L shape in a plan view, and the exhaust recirculation pipe first portion 23 is bent in a gentle shape in a plan view and extends linearly in a side view.

  On the other hand, the exhaust gas recirculation pipe second portion 26 is bent in a substantially crank shape in a plan view and a side view. Then, the exhaust gas recirculation pipe second portion 26 exits from the exhaust gas recirculation pipe first portion 23 and rises upward, and then faces the EGR cooler 10. For this reason, the fourth spherical joint 28 is closer to the exhaust pipe first portion 17 than the line connecting the second spherical joint 24 and the third spherical joint 27. That is, the exhaust gas recirculation pipe first portion 23 and the exhaust gas recirculation pipe second portion 26 are connected in a square shape, and the apex of the square shape faces the exhaust pipe first portion 17 (the exhaust gas recirculation pipe first portion). (The pipe line composed of the portion 23 and the exhaust recirculation pipe second portion 26 is in a convex posture toward the exhaust pipe first portion 17).

  The structure of each spherical joint is the same, and the cross section is shown in FIG. 4 taking the fourth spherical joint 28 as an example. As shown in FIG. 4, the spherical joints 14, 24, 27, and 28 have a first cylindrical portion 31 and a second cylindrical portion 32 that are arranged substantially concentrically. While the first flange plate 33 is provided integrally, a second flange plate 34 is fixed to the second cylindrical portion 32 by welding, and the first flange plate 33 opens toward the second flange plate 34. A flange 35 is formed, and a seal body 36 is inserted between the flange 35 and the second flange plate 34. Further, both flange plates 33 and 34 are connected by bolts 37, nuts 38 and springs 39. It is sandwiched. Both flange plates 33 and 34 are formed by rounding the rhombus corners.

  In the illustrated example, the nut 38 is disposed on the first flange plate 33 and the spring 39 is disposed on the second flange plate 34, but the opposite arrangement may be employed. The contact surface between the inner surface of the bowl-shaped portion 35 and the seal body 36 is a circular arc surface having one center. Therefore, even if both the cylindrical portions 31 and 32 move relative to each other so as to cross their axial centers, The state portion 35 and the sealing body 36 are kept in surface contact. Thereby, both the cylinder parts 31 and 32 are permitted to rotate relatively in an arbitrary direction while ensuring sealing performance.

  The second flange plate 34 may be fixed to the pipe line itself by welding or the like without using the second cylindrical portion 32. The first flange plate 33 of the first spherical joint 14 is fixed to the collective portion 12 a of the exhaust manifold 12.

(3) Summary As shown schematically in FIG. 5, the engine body 1 is supported on the vehicle body 41 via a rubber mount 40. For this reason, the engine body 1 has a vibration system independent of the vehicle body 41. On the other hand, for example, the exhaust pipe second portion 19 of the exhaust pipe 13 is supported by the vehicle body 41 via the suspension support member 42.

  Accordingly, the vibration of the vehicle body 41 and the vibration of the engine body 1 act on the exhaust pipe first portion 17, but relative movement between the engine body 1 and the exhaust pipe first portion 17 is permitted by the first spherical joint 14. Since the relative movement between the vehicle body 41 and the exhaust pipe first portion 17 is allowed by the second spherical joint 24, a strong stress is applied to the exhaust pipe first portion 17 due to the difference between the vibration of the engine body 1 and the vibration of the vehicle body 41. Can be prevented.

  That is, as shown in FIG. 5, the exhaust pipe first portion 17 can rotate relative to both the engine body 1 and the vehicle body 41, but it is assumed that there is only one exhaust recirculation pipe 29. With the structure, even if both ends of the exhaust gas recirculation pipe 29 are connected by spherical joints, the engine main body 1, the exhaust pipe first portion 17 and the EGR pipe have only a simple truss structure. The exhaust pipe first portion 17 and the exhaust gas recirculation pipe 29 cannot be rotated relative to each other by virtue of the fact that the expansion and contraction due to heat of the first portion 17 and the exhaust pipe first portion 17 can be allowed. A strong stress acts on the exhaust pipe 17 and the exhaust gas recirculation pipe 29.

  On the other hand, in the present embodiment, the exhaust gas recirculation pipe 29 is separated into the first part 23 and the second part 26, and the engine body 1, the exhaust pipe first part 17, the exhaust gas recirculation pipe first part 23, and the exhaust gas. Since a kind of four-point link mechanism is configured with the reflux pipe second portion 26, when the exhaust pipe first portion 17 rotates as shown by a dotted line and a one-dot chain line in FIG. 23 and the exhaust gas recirculation pipe second portion 26 also rotate relative to each other.

For this reason, even if the vibration system of the engine body 1 and the vibration system of the vehicle body 41 are different, the difference in the vibration system is that the exhaust pipe first portion 17, the exhaust recirculation pipe first portion 23, and the exhaust recirculation pipe second portion 26. Absorbed by rotation. As a result, excessive stress does not occur in the exhaust pipe first portion 17, the exhaust recirculation pipe first portion 23, and the exhaust recirculation pipe second portion 26, and high durability can be ensured. The exhaust gas recirculation pipe 29 is inclined so that its starting end is the lowest, and the lowermost end, which is the starting end, is connected to the catalyst case 16 via the second spherical joint 24. Even if the exhaust gas stays in the tank and condensed water is generated after the engine is stopped, the condensed water flows down to the exhaust pipe 13. Therefore, the problem of corrosion of the exhaust gas recirculation pipe 29 can also be prevented.

In the present embodiment, the exhaust gas recirculation pipe 29 is separated into an exhaust gas recirculation pipe first part 23 and an exhaust gas recirculation pipe second part 26. Therefore, in relation to the claims, the exhaust pipe first portion 17 corresponds to the start side pipe line, the exhaust recirculation pipe second part 26 corresponds to the end side pipe line, and the exhaust recirculation pipe first part 23 corresponds to the middle. Corresponds to a pipeline. Each spherical joint 14,24,27,28 is that make up the means for allowing relative rotation of the pipe.

  As described above, in the present embodiment, the exhaust recirculation pipe first portion 23 and the exhaust recirculation pipe second portion 26 are connected (coupled) in a square shape, and are directed to the exhaust pipe first portion 17. It has a convex shape. As is apparent from the display of FIG. 5, when the exhaust gas recirculation pipe first portion 23 and the exhaust gas recirculation pipe second portion 26 rotate in conjunction with the rotation of the exhaust gas pipe first portion 17, Only the crossing angle between the first portion 23 and the exhaust recirculation pipe second portion 26 changes, and the overall layout does not change. Therefore, the rotation of the exhaust gas recirculation pipe first portion 23 and the exhaust gas recirculation pipe second portion 26 is smooth and has a compact configuration. This is one of the advantages of this embodiment.

  Further, the exhaust recirculation pipe first portion 23 and the exhaust recirculation pipe second portion 26 tend to rotate due to their own weights. However, when the arrangement mode of this embodiment is adopted, the exhaust recirculation pipe first portion 23 and the exhaust recirculation pipe first portion 23 When the exhaust gas recirculation pipe second portion 26 tries to rotate under its own weight, both of them tend to have a depression angle that tends to shorten the overall length of the exhaust gas recirculation pipe 19. For this reason, as shown by a one-dot chain line in FIG. 5, the exhaust pipe first portion 17 rotates upward with the first spherical joint 14 as a fulcrum, or the exhaust pipe first portion 17 is deformed into an upward convex bow. In other words, the exhaust gas recirculation pipe first portion 23 and the exhaust gas recirculation pipe second portion 26 rotate relatively smoothly to reduce the depression angle.

  Conversely, as indicated by the dotted line in FIG. 5, the exhaust pipe first portion 17 rotates downward with the first spherical joint 14 as a fulcrum, or the exhaust pipe first portion 17 is deformed into a downward convex bow. Then, the exhaust gas recirculation pipe first part 23 and the exhaust gas recirculation pipe second part 26 are relatively rotated so as to increase the depression angle, and the entire length of the exhaust gas recirculation pipe 29 tends to become long. Even in this case, the exhaust gas recirculation pipe first portion 23 and the exhaust gas recirculation pipe second portion 26 do not butt and rotate smoothly. These points are also one of the advantages of this embodiment.

  Also, as shown in FIG. 3, the angle θ formed by the line 43 connecting the two bolts 37 in each spherical joint 14, 24, 27, 28 with respect to the horizontal plane 44 is generally kept within 45 °. The exhaust pipe first portion 17, the exhaust gas recirculation pipe first portion 23, and the exhaust gas recirculation pipe second portion 26 can be easily rotated.

  That is, both the engine body 1 and the vehicle body 41 vibrate in the vertical direction. For this reason, the exhaust pipe first portion 17 and the like are also subjected to the action of rotating in the vertical direction. If the bolts 37 are arranged in a vertical posture, the spring 39 must be greatly deformed in order to rotate the tube, and thus a large force is applied to the rotation of the tube. Since the bolts 37 are arranged in a posture that is closer to the horizontal posture than the vertical posture, an excessive force is not applied to the spring 39, and the tube is smoothly rotated.

Further, as can be understood from FIG. 3, the above-mentioned θ is almost zero at the location of the first spherical joint 14, while it is the largest at the location of the second spherical joint 24. The tube first portion 17 tends to rotate around the first spherical joint 14 as a fulcrum. Further, since θ of the second to fourth spherical joints 24, 27, 28 provided in the exhaust gas recirculation pipe 29 is larger than θ of the first spherical joint 14 provided in the exhaust pipe 13, The resistance to movement is greater at the exhaust recirculation pipe 29 than at the exhaust pipe 13.

And, since the above θ is in the relationship of the third spherical joint 27 <the fourth spherical joint 28 <the second spherical joint 24 at the location of the exhaust gas recirculation pipe 29, looking at the whole exhaust gas recirculation pipe 29, The third spherical joint 27 is in a state where it can be moved relatively easily. For this reason, the exhaust gas recirculation pipe 29 smoothly rotates with the third spherical joint 27 as a fulcrum in response to the exhaust pipe first portion 17 smoothly rotating with the first spherical joint 14 as a fulcrum. It has become. Accordingly, the exhaust purification device 21 having a large weight is allowed to vibrate easily following the vibration of the vehicle body 41, and a specific connection portion is not burdened ( not concentrated) .

The present invention can be embodied in various ways other than the above-described embodiment. For example, but it may also be divided into the exhaust pipe and the exhaust circulation pipe into a plurality respectively. If the exhaust collection function incorporated in the cylinder head, the exhaust pipe is connected to an exhaust hole in the cylinder head.

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

DESCRIPTION OF SYMBOLS 1 Engine body 2 Cylinder block 3 Cylinder head 4 Head cover 7 Intake manifold which comprises intake system 9 Surge tank 10 EGR gas introduction part 12 Exhaust manifold (exhaust part)
13 Exhaust pipe 14 First spherical joint 16 Catalyst case 17 Exhaust pipe first part (starting end side pipe line)
19 Exhaust pipe second part 21 Exhaust gas purification device 23 Exhaust gas recirculation pipe first part (intermediate pipe line)
24 Second spherical joint 26 Exhaust gas recirculation pipe second part (end pipe line)
27 Third spherical joint 28 Fourth spherical joint 29 Exhaust gas recirculation pipe
35 bowl
36 Seal body
37 volts
38 nuts
39 Spring

Claims (1)

An intake section and an exhaust section provided in the engine body, an exhaust pipe connected to the exhaust section, an exhaust purification device interposed in the middle of the exhaust pipe, and a downstream of the exhaust purification apparatus in the exhaust pipe An exhaust gas recirculation pipe branched from the side and connected to the intake part,
The exhaust gas from the exhaust part to the intake part includes: a start side pipe connected to the exhaust part; a termination side pipe connected to the intake part; and the exhaust purification device and the termination side pipe Is divided into three or more pipelines with one or a plurality of intermediate pipelines located between the exhaust pipe and the start pipe, the terminal pipe and the suction pipe, and adjacent to each other. The pipes are connected to each other so as to be relatively rotatable,
The connecting portion of each pipe line is constituted by a spherical joint in which a flange-like part and a sealing body are closely attached by a spring and a pair of bolts so as to be relatively rotatable , and each pipe line has a resistance. It is allowed to rotate in the vertical direction in the state ,
In addition, an angle formed by a line connecting a pair of bolts with respect to the horizontal in the spherical joint to which each pipe constituting the exhaust gas recirculation pipe is connected is a pair of in the spherical joint to which the start-end side pipe is connected. The line connecting the bolts is larger than the angle formed with respect to the horizontal,
Internal combustion engine for vehicles.

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