JP2019120179A - Engine with EGR - Google Patents

Abstract

[Problem] To provide an engine with EGR that is improved so that the EGR pipe can be easily cooled and the increase in engine length can be suppressed by comprehensively reviewing and devising the structure of the engine case and the replacement of the EGR pipe. offer. An EGR pipe (6) for guiding EGR gas (g) to an intake path (5) is piped through an engine case (k) in a state facing a cooling water passage (w) in the engine case (k). and the outer peripheral portion 6G of the EGR pipe 6 are provided with a seal mechanism S. The seal mechanism S includes a seal ring 21 interposed between the extraction portion 2B and the EGR pipe 6, and a fastener e capable of tightening the seal ring 21 in the direction of the axis P of the EGR pipe 6. The seal ring 21 is pressed in the direction of the axis P by e. [Selection drawing] Fig. 7

Description

  The present invention relates to an engine with EGR, such as a diesel engine equipped with EGR (Exhaust Gas Recirculation) that is exhaust gas recirculation.

  In an engine with EGR, part of the exhaust gas is returned to the intake passage such as an intake manifold as EGR gas to reduce the nitrogen oxides in the exhaust gas and to improve the fuel efficiency at partial load. As this engine with EGR, those disclosed in Patent Document 1 and the like are known.

  In a conventional engine with EGR, a structure is adopted in which an EGR pipe for flowing EGR gas is piped to the intake side by bypassing the lateral outside of the cylinder head in the engine case. In the case of Patent Document 1, as shown in FIG. 3, an EGR pipe (15) communicating the exhaust manifold (13) with the intake manifold (14) is bypassed through the lateral outside of the cylinder head (12). It is done.

JP, 2014-190171, A JP, 2010-236397, A

  The conventional engine with EGR has a disadvantage that the overall length of the engine becomes long because the EGR pipe which becomes high temperature is piped through the lateral and outer sides of the engine. Since the EGR pipe is heated to a high temperature, an increase in size can not be avoided because a heat radiation gap is secured around the EGR pipe. In addition, since the EGR pipe is passed laterally outward of the engine on the side of the flywheel due to the layout of the engine, there is a disadvantage that it is difficult to enjoy the air cooling effect by the cooling air.

  In particular, in the structure in which the EGR cooler (15) bulkier than the EGR pipe is disposed on the flywheel side of the in-line multi-cylinder engine as in the engine disclosed in Patent Document 2, the above-mentioned disadvantages are further increased. It was noticeable.

  The object of the present invention is to improve the EGR pipe so that the EGR pipe can be easily cooled and the increase of the engine length can be suppressed by comprehensively reviewing and devising the structure of the engine case and the replacement of the EGR pipe. To provide an integrated engine.

The present invention relates to an engine with EGR,
An EGR pipe 6 for guiding the EGR gas g to the intake passage 5 is piped through the engine case k in a state facing the cooling water passage w in the engine case k,
A sealing mechanism S is provided for sealing between the takeout portion 2B of the EGR pipe 6 and the outer peripheral portion 6G of the EGR pipe 6 in the engine case k.

According to a second aspect of the present invention, in the engine with EGR of the present invention,
The seal mechanism S includes a seal ring 21 interposed between the takeout portion 2B and the EGR pipe 6, and a fastener e capable of tightening the seal ring 21 in the axial center P direction of the EGR pipe 6. The seal ring 21 is pressed in the axial center P direction by the fastener e.

According to a third aspect of the present invention, in the engine with EGR according to the second aspect,
The fastener e is characterized by including a nut 22 which is loosely fitted to the EGR pipe 6 and can be screwed to the engine case k.

According to a fourth aspect of the present invention, in the engine with EGR of the present invention,
The seal mechanism S is characterized by being formed by casting and wrapping the EGR pipe & in the engine case k.

According to a fifth aspect of the present invention, in the engine with EGR according to any one of the first to fourth aspects of the present invention,
A case end 2A, which is an end of the engine case k, is partially bulged outward, and the EGR pipe 6 is passed through an outwardly bulged portion 7 of the case end 2A. It is characterized by

According to a sixth aspect of the present invention, in the engine with EGR according to any one of the fifth to the fifth aspects of the present invention,
The engine case k is a cylinder head 2.

  According to the present invention, since the EGR pipe passes through the inside of the engine case, the engine length can be shortened as compared with the case of piping to the outside. And since the EGR pipe faces the cooling water passage in the engine case, cooling of the EGR pipe by the cooling water becomes possible, and the EGR pipe which becomes high temperature can be efficiently cooled using the existing equipment.

  Then, the EGR pipe can be favorably supported in a state in which the coolant does not leak, while passing the EGR pipe through the engine case.

  As a result, by comprehensively reviewing and devising the structure of the engine case and the replacement of the EGR pipe, it is possible to easily cool the EGR pipe and prevent the increase of the engine length while preventing the leakage of the cooling water. It is possible to provide an engine with EGR improved to be

Transverse sectional view of the cylinder head end showing the structure near the EGR pipe Longitudinal sectional view of cylinder head end showing structure near EGR pipe Side view showing the EGR pipe (A) The front view by arrow X of FIG. 3 which shows each part of an EGR pipe, (b) is sectional drawing in the YY line of FIG. Schematic showing the cross-sectional structure of the end of the cylinder head from the lateral direction Schematic perspective view showing the end of the cylinder head with the EGR pipe The seal structure of an EGR pipe and an engine case is shown, (a) is a cross-sectional view of the main part, (b) is a cross-sectional view of the main part showing another seal structure.

  Hereinafter, an embodiment of an engine with EGR according to the present invention will be described in the case of an industrial engine with reference to the drawings. The engine case k is a concept including the cylinder head 2 and the cylinder portion 1A. Also, let the exhaust manifold 4 side of the engine case k be the left, and the intake manifold 5 side be the right.

  As shown in FIG. 6, in a vertical industrial engine E, the cylinder head 2 is assembled on the cylinder portion 1A which is the upper portion of the cylinder block 1, and the cylinder head cover 3 is assembled on the cylinder head 2 It is done. An exhaust manifold 4 is assembled on one end side of the cylinder head 2 on the left and right sides, and an intake manifold 5 is assembled on the other end side.

  The industrial engine E is equipped with an EGR device A that returns part of the exhaust gas as EGR gas to the intake path. As shown in FIG. 6, the EGR device A is configured to include an EGR pipe 6 which is a pipe line connecting the exhaust manifold 4 and the intake manifold 5 and an EGR cooling mechanism r capable of cooling the EGR pipe. It is done.

  The EGR pipe 6 is piped through the inside of a cylinder head 2 which is an example of the engine case k. At the case end 2A, which is the front and rear end of the cylinder head 2, a bulging case portion (an example of a bulging portion) 7 is formed so as to expand outward in order to incorporate the EGR pipe 6. In FIG. 6, 4A is a part of the exhaust manifold 4 and is a mounting base for bolting the exhaust manifold 4 to the cylinder head 2.

As shown in FIGS. 1 to 3, the EGR pipe 6 as an example has a main body pipe 6A and a mounting flange 6B fixed to the main body pipe 6A.
The main body pipe 6A includes a basic pipe portion 8, a narrow diameter portion 9 having a slightly reduced diameter formed on the base end side thereof, and a tapered pipe portion formed between the basic pipe portion 8 and the small diameter portion 9 It has 10 and. The basic pipe portion 8 is formed into a deformed pipe portion 8A having a complicated cross-sectional shape, with the exception of both longitudinal end portions. The EGR pipe 6 may be formed of a general pipe.

As shown in FIGS. 3 and 4 (a), in the deformed tube portion 8A, a plurality of strip-shaped deep groove portions 11 extending in the direction of the pipe axis P with the outer peripheral surface greatly recessed are extending at a plurality of locations (six locations) in the circumferential direction. It is a part that is formed into. The long deep groove portion 11 can greatly increase the surface area of the EGR pipe 6 as compared with a simple circular pipe.
The deep groove portion 11 has a groove bottom surface 11a and a pair of left and right groove side surfaces 11b and 11b, and is recessed with a constant groove width d to a groove bottom surface 11a having a diameter of about half the diameter of the basic pipe portion 8 ing.

  As shown in FIG. 3 and FIG. 4 (b), the mounting flange 6B is formed of a thick plate main body flange 12 having six mounting holes 12a, 12a at its outer peripheral portion, and the main body pipe is welded or the like. It is integrated with the open end of the basic pipe portion 8 of 6A. The mounting flange 6B is mounted at a position slightly inward from the end of the basic pipe portion 8 as shown in FIG. The main body pipe 6A and the mounting flange 6B are desirably made of an aluminum alloy having small specific heat and excellent thermal conductivity and high strength, but may be made of other metals. The aluminum alloy has an advantage that it is less expensive than the SUS material while having the same corrosion resistance as the SUS material.

As shown in FIGS. 1, 2 and 5, the EGR pipe 6 is piped through the inside of the bulging case 7 of the cylinder head 2, and is accommodated in the bulging case 7 of the EGR pipe 6. Most of the parts are provided facing the passage w inside the cylinder head 2. The bulging case portion 7 is formed by bulging outward in a semicircular arc shape (see FIG. 5) on the lower portion (a partial example) of the case end portion 2A.

  The EGR pipe 6 is inserted, for example, from a mounting hole 19 formed in a side wall (right side wall) 2B on the side of the intake manifold 5 of the cylinder head 2 and the small diameter portion 9 is a side wall on the side of the exhaust manifold 4 of the cylinder head 2 (Left side wall) Press-fit or close-fit fit into gas inlet port 15 which is a circular hole formed in 2C, and mounting flange 6B on the intake manifold side of cylinder head 2 by two bolts (not shown). It is attached to the side 2a. In this case, the diameter of the mounting hole 19 is slightly larger than the diameter of the gas inlet 15.

  As shown in FIG. 1, FIG. 2 and FIG. 5, the cooling water passage w in the cylinder head 2 is located in the lower water passage w1 located in the lower part of the cylinder head 2, the upper water passage w2 located in the upper part, and the end. While having the end part water channel w3, it has the outer peripheral water channel w4 formed in the outer peripheral side of the EGR pipe 6 in the bulging case 7. The cooling water passage w is formed to surround the EGR pipe 6 due to the presence of the outer peripheral water passage w4. That is, the EGR cooling mechanism r is configured by providing the EGR pipe 6 facing the cooling water passage.

  As shown in FIG. 6, the exhaust gas G from the combustion chamber (not shown) is discharged from the exhaust outlet 13 of the cylinder head 2 into the exhaust manifold 4 by the EGR device A, and a portion thereof is mixed with the EGR gas g. As a result, the gas intake port 15 (see FIGS. 1 and 2) of the cylinder head 2 is entered from the outlet hole 14 and then reduced into the intake manifold 5 through the EGR pipe 6. The internal portion of the cylinder head 2 of the EGR pipe 6 refers to the basic pipe portion 8, the tapered pipe portion 10, and a part of the small diameter portion 9 from FIG.

  Since the EGR pipe 6 is accommodated in the bulging case portion 7, compared with the conventional EGR device in which the EGR pipe is piped outside the cylinder head as a separate one, the cylinder head 2 is laterally outward The amount of overhang can be reduced (suppressed). In addition, since the outer peripheral water passage w4 is also present on the outer periphery of the overhang side of the EGR pipe 6 in the bulging case portion 7, as shown in FIGS. 1 and 5, the outer peripheral water passage w4 and the end water passage w3 The cooling water 20 flowing through the lower water channel w1 cools the refrigerant, and the function of the EGR cooler can be efficiently exhibited.

  Therefore, as the engine, the EGR device A and the EGR cooling mechanism r according to a structural device in which the cylinder head 2 is slightly expanded to incorporate the EGR pipe, while the EGR gas g is cooled by effectively using the existing cooling water 20 An EGR-equipped engine E capable of reducing the bulkiness in the lateral direction is realized. Since the EGR pipe 6 can be effectively cooled, there is also an advantage that the external EGR cooler (not shown) can be made unnecessary or miniaturized.

  As shown in FIGS. 1, 2 and 5, guide portions 16 (solid lines in FIGS. 1 and 2; imaginary lines in FIG. 5) for guiding and guiding the cooling water 20 to the radially outer portion of the EGR pipe 6 in the cooling water passage w. It is convenient to have a configuration provided with The guide portion 16 is a guide main body 17 formed so as to project to the lower water passage w1 below the EGR pipe 6 and a circumferential formed so as to project to the outer circumferential water passage w4 so as to surround the EGR pipe 6 at a half circumference. It comprises the guide part 18 and is comprised. The guide portion 16 may have only the guide main body 17 or may be formed by casting.

  The provision of the guide portion 16 promotes the flow of the cooling water 20 flowing through the cooling water passage w into the outer peripheral water passage w4, thus providing an economical means (guide portion 16) with almost no increase in cost. There is an advantage that the water cooling action of the EGR pipe 6 (EGR gas g) by the cooling water can be enhanced.

  Further, as shown in FIG. 1, the cooling water from the cooling water channel (not shown) of the cylinder block 1 is sent from the left and right water channels 2L and 2R to the lower water channel w1 in the cylinder head 2. Therefore, the cooling water from the left and right water channels 2L, 2R is smoothly divided into the outer peripheral water channel w4 without interference due to the guide portion 16 located between the left water channel 2L and the right water channel 2R. The preferable effect of guiding is also exhibited.

[About seal mechanism]
In the engine with EGR according to the present invention, as shown in FIG. 7, a seal mechanism S for sealing between an extraction portion 2B of the EGR pipe 6 in the engine case k and an outer peripheral surface (an example of the outer peripheral portion) 6G of the EGR pipe 6 Is provided. The seal mechanism S seals (seals) between the EGR pipe 6 passed through the engine case k and the engine case k, and blocks leakage of the cooling water 20 from the cooling water passage (water jacket). .

  The EGR pipe 6 as an example shown in FIGS. 1 to 3 and the like has a structure in which the mounting flange 6B is fixed to the cylinder head 2 by bolting it to the side wall 2B. As shown in FIG. 5, the mounting flange 6B is not provided, and the basic pipe portion 8 is attached to the side wall (extraction site) 2B in a sealed state. The EGR pipe 6 not having the mounting flange 6B may be a pipe having a uniform diameter without the deep groove portion 11, but for the sake of simplicity the overall view is omitted and the end on the seal side is shown in FIG. .

  The seal mechanism S is, as shown in FIG. 7A, a seal ring 21 interposed between a side wall 2B on the side of the intake manifold 5 which is an example of the takeout portion of the cylinder head 2 and the EGR pipe 6; The seal ring 21 is provided with a fastener e capable of fastening the seal ring 21 in the axial center P direction of the EGR pipe 6, and the seal ring 21 is pressed by the fastener e in the axial center P direction. The fastener e is loosely fitted to the EGR pipe 6 and is constituted by a nut (union nut) 22 which can be screwed to the side wall 2B. A ring-shaped retainer 23 is provided between the nut 22 and the seal ring 21.

  The mounting hole 19 of the side wall 2B connects the outer female screw portion 24, the inner loose fitting portion 25 smaller in diameter than the female screw portion 24, and the loose fitting portion 25 and the female screw portion 24. And 26 are formed in a screw hole. The seal ring 21 is provided at the right end of the inner peripheral surface 21a fitted to the basic pipe portion 8 of the EGR pipe 6, the right expanded taper outer peripheral surface 21b tapered and fitted to the right expanded taper inner peripheral surface 26, and the right expanded taper outer peripheral surface 21b. It is a sealing material made of an aluminum material having the following right narrowing tapered outer peripheral surface 21c.

  The nut 22 is a component that has an external thread 22a that can be screwed to the internal thread 24, a hexagonal nut 22b, and a pressing end face 22c and is loosely fitted to the basic pipe 8. The retainer 23 has a right narrow tapered inner circumferential surface 23a which is tapered and fitted to the right narrow tapered outer circumferential surface 21c, a pressure receiving end surface 23b which abuts against the pressing end surface 22c, and an outer circumferential surface 23c which is loosely fitted to the female screw portion 24. It is a strength part.

  As shown in FIG. 7A, with the EGR pipe 6 passing through the mounting hole 19 and the seal ring 21 and the retainer 23 being inserted between the EGR pipe 6 and the mounting hole 19, the nut 22 is internally threaded. Screw the part 24 into place. Then, when the nut 22 is turned in and tightened, the pressing end surface 22c of the nut 22 abuts on the pressure receiving end surface 23b, and presses the seal ring 21 in the axial center P direction via the retainer 23.

  The seal ring 21 pressed in the axial center P direction by the abutment of the tapered surfaces 23a and 21c is mainly the portion between the outer peripheral surface 6G of the EGR pipe 6 and the tapered inner peripheral surface 26 of the mounting hole 19 By expanding and deforming in the radial direction of P and strongly contacting the outer peripheral surface 6G and the tapered inner peripheral surface 26, the space between the both 6G and 26 is effectively sealed. That is, by the tightening of the nut 22 by the sealing mechanism S, the EGR pipe 6 is fixedly supported by the cylinder head 2 and the space between the both is sealed. In this case, when the nut 22 is tightened, the retainer 23 and the seal ring 21 do not rotate relative to each other, and the nut 22 and the retainer 23 rotate relative to each other.

  As shown in FIG. 7B, the sealing mechanism S does not have the retainer 23 and has a configuration using a clamp e by a nut 22 integrally formed with a portion that plays the role of the retainer 23. That is, the nut 22 is provided with a right narrowed tapered inner peripheral surface 22d which is taper-fitted to the right narrowed tapered outer peripheral surface 21c of the seal ring 21 instead of the pressing end surface 22c shown in FIG. 7A. In this case, when the nut 22 is tightened, the right-narrowed tapered inner peripheral surface 22 d and the right-narrowed tapered outer peripheral surface 21 c rotate relative to each other.

  By adopting the sealing mechanism S, the EGR pipe 6 can be well supported in a state in which the cooling water does not leak while being configured to pass the EGR pipe 6 to the engine case k. Since the EGR pipe 6 can be supported in the mounting hole 15 of the cylinder head 2 in a sealed state, a reliable sealing performance is obtained as compared to the means for bolting the mounting flange 6B to the side wall 2B (see FIGS. 1 and 2). However, there is an advantage that it is possible to save the space for the arrangement place.

[Regarding the left side wall 2C and the EGR pipe 6]
As shown in FIGS. 1 and 2, the left side wall 2C of the cylinder head 2 and the EGR pipe 6 are in close contact with each other by casting (or press-fitting) into the gas intake port 15 of the small diameter portion 9. The diameter portion 9 is fixedly supported by the side wall 2C. That is, it is the seal mechanism S configured by casting.

  That is, when casting the cylinder head 2, the EGR pipe 6 is set in a mold by using a core or the like in a state where the small diameter portion 9 is positioned at a planned location to be the gas intake port 15, It casts in the state and produces the cylinder head 2 by which the EGR pipe 6 was cast-wrapped. That is, integral casting of the EGR pipe 6 by casting is substantially equivalent to one having the function of the sealing mechanism S.

  It is possible to firmly support the small diameter portion 9 on the left side wall 2C (EGR pipe 6) in a close contact state while omitting the sealing mechanism by the mechanism as shown in FIG. 7A. Further, the length of the EGR pipe 6 can be shortened as compared with a configuration in which the pipe end is slightly extended outward, and it is preferable also in terms of vibration resistance and durability.

[Another embodiment]
It is possible to adopt a configuration in which the mechanical seal mechanism S is provided on both the EGR pipe 6 and the left and right side walls 2C and 2b, and a configuration in which both the EGR pipe 6 and the left and right side walls 2C and 2b are cast and wrapped It is possible.
The material of the EGR pipe 6 can be replaced with various metals and the like. Further, the seal ring 21 can be variously changed and set, such as an elastic material or a flexible material.

[Remarks]
The "extraction site" is a position where the EGR pipe 6 is passed through or supported by the engine case k, and the left and right side walls 2C and 2B are both "extraction sites" of the EGR pipe 6.

Reference Signs List 2 cylinder head 2A case end 2B extraction part 5 intake path 6 EGR pipe 6G outer peripheral part 7 bulging part 21 seal ring 22 nut S seal mechanism e fastener g EGR gas k engine case w cooling water passage

Claims (6)

An EGR pipe for guiding the EGR gas to the intake path is piped through the engine case, facing the cooling water passage in the engine case,
An engine with EGR is provided with a seal mechanism for sealing between an extraction portion of the EGR pipe and an outer peripheral portion of the EGR pipe in the engine case.   The seal mechanism includes a seal ring interposed between the takeout site and the EGR pipe, and a fastener capable of clamping the seal ring in the axial direction of the EGR pipe, and the clamp mechanism 2. The engine with EGR according to claim 1, wherein the seal ring is pressed in the axial direction.   The engine with EGR according to claim 2, wherein the fastener comprises a nut which is loosely fitted to the EGR pipe and can be screwed to the engine case.   The engine with EGR according to claim 1, wherein the seal mechanism is configured by casting and wrapping the EGR pipe in the engine case.   The case end which is the end of the engine case is partially expanded outward, and the EGR pipe is passed through the outward expanded portion of the case end. An engine with EGR according to any one of the preceding claims.   The engine with EGR according to any one of claims 1 to 5, wherein the engine case is a cylinder head.

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