JP2021110234A - Exhaust manifold for engine with supercharger - Google Patents

Abstract

To provide an exhaust manifold for an engine with a supercharger, which is comprehensively improved to be so compact that it can be arranged in a narrow space while eliminating/suppressing exhaust interference.SOLUTION: An exhaust manifold 10 for an engine with a supercharger includes a plurality of exhaust branch pipes 10A connected to respective exhaust ports, and a junction pipe part 10B communicating the ends of the exhaust branch pipes 10A with each other. An exhaust outlet part 10C to a supercharger 12 is provided at another position than the center in the longitudinal direction of the junction pipe part 10B, the exhaust outlet part 10C is taken out of the junction pipe part 10B in a direction crossing the longitudinal direction and formed into the state of having a curved circumvention shape.SELECTED DRAWING: Figure 6

Description

The present invention relates to an exhaust manifold applied to a diesel engine mounted on an agricultural tractor or a backhoe, that is, an exhaust manifold for an engine with a supercharger.

In an industrial engine such as a diesel engine for a tractor, as disclosed in Patent Document 1, a plurality of exhaust branch pipes connected to each exhaust port of a cylinder head and a confluence of the ends of the branch pipes are communicated with each other. An exhaust manifold having a pipe portion and formed into one component is used. Since the exhaust gas has a high temperature and severe thermal conditions, the exhaust manifold is generally made of cast iron.

In particular, in an engine with a supercharger (turbocharger) as disclosed in Patent Document 2, in the exhaust manifold, the exhaust gas emitted from each exhaust port is collected at the merging pipe portion, and the turbine inlet of the supercharger is collected. The configuration to send to the side is adopted. Since the supercharger is placed close to the exhaust manifold in order to make the engine compact, there is a problem that (1) the shape of the exhaust manifold tends to be complicated.

In addition, there were the following problems and improvements.
(2) With a small engine, the space on the mounting layout is small and it is difficult to be flexible, so it is almost impossible to arrange the exhaust outlet to the turbocharger at the center of the exhaust manifold in the longitudinal direction.

(3) Due to the above (2), the distance (port length) from each exhaust branch pipe to the exhaust outlet portion is too different and the balance becomes poor, and it is difficult to improve the performance of the turbocharger. For example, in an in-line 4-cylinder engine, the third exhaust branch pipe (exhaust port) is closest to the exhaust outlet, so the first exhaust branch and the third exhaust branch at the combustion timing of 1-3-4-2. There is an inconvenience that the exhaust easily interferes with the pipe.

Japanese Unexamined Patent Publication No. 2013-199881 Japanese Unexamined Patent Publication No. 2013-96347

An object of the present invention is to provide a comprehensively improved exhaust manifold for an engine with a supercharger so that it can be placed in a narrow space and can be made compact while eliminating or suppressing exhaust interference. It is in.

The present invention relates to an exhaust manifold for an engine with a supercharger.
A supercharger having a plurality of exhaust branch pipes connected to each exhaust port and a merging pipe portion that communicates the ends of the branch pipes with each other at a position other than the central portion in the longitudinal direction of the merging pipe portion. Exhaust outlet to
The exhaust outlet portion is taken out from the confluence pipe portion in a direction intersecting with the longitudinal direction thereof, and is formed in a state having a curved detour shape.

Regarding the present invention, refer to claims 2 to 7 for feature configurations and means other than the above-mentioned configurations (means).

According to the present invention, the length of the exhaust outlet portion can be made longer than that in the case where the exhaust outlet portion is not curved. Therefore, even if the exhaust outlet portion is located in the longitudinal direction of the confluence pipe portion other than the central portion, the exhaust gas in each cylinder is exhausted. It is possible to suppress variations in the length of the passage from the branch pipe to the turbocharger.

As a result, it is possible to provide a comprehensively improved exhaust manifold for an engine with a supercharger so that it can be arranged in a narrow space and can be made compact while eliminating or suppressing exhaust interference.

In addition, if the cross-sectional area of the detoured portion at the exhaust outlet is likely to be restricted due to space restrictions, etc., the cross-sectional width can be expanded by adding an angle R at the boundary between the passage between the exhaust confluence and the exhaust outlet. If this is done, there is an advantage that the flow of exhaust gas from the merging pipe portion to the exhaust outlet portion can be made smoother.

Front view of diesel engine with supercharger Left side view of the engine of FIG. Rear view of the engine of FIG. Left side view of the exhaust manifold Cross-sectional plan view of the exhaust manifold cut horizontally at the confluence pipe and viewed from above Rear view of the cross section of the exhaust manifold cut vertically at the exhaust outlet and viewed from behind

Hereinafter, an embodiment of an exhaust manifold for an engine with a supercharger according to the present invention will be described with reference to the drawings regarding an exhaust manifold for an industrial diesel engine suitable for an agricultural tractor or the like.

FIGS. 1 to 3 show an in-line 4-cylinder diesel engine with a supercharger (hereinafter, simply abbreviated as an engine) E. In this engine E, the cylinder head 2 is assembled on the cylinder block 1, and the head cover 3 is assembled on the cylinder head 2. An oil pan 4 is assembled under the cylinder block 1, and an exhaust treatment device 5 is mounted above the head cover 3.

A transmission case 9, a crank pulley (drive pulley) 6, a water pump 7, and the like are mounted on the front side of the engine E, and a flywheel 8 is mounted on the rear side. Exhaust manifold (exhaust manifold for engine with supercharger) 10, EGR cooler 11, supercharger 12, oil filter 13, etc. are installed on the left side of engine E, and intake manifold 14, oil level gauge 15, etc. are installed on the right side. Has been deployed.

As shown in FIG. 2, the exhaust manifold 10 is attached to the left side surface of the cylinder head 2 by bolting, and the exhaust introduction portion 12C of the supercharger 12 is bolted to the exhaust outlet portion 10C of the exhaust manifold 10. Are connected by. Further, at a position directly below the exhaust manifold 10, the EGR cooler 11 is arranged in a front-rear posture in a state where both ends are supported by the exhaust manifold 10. The supercharger 12 is a turbocharger having a turbine 12B having an exhaust introduction unit 12C and a compressor 12A.

As shown in FIGS. 4 to 6, the exhaust manifold 10 includes four (a plurality of examples) exhaust branch pipes 10A connected to the exhaust ports p1, p2, p3, and p4 of the cylinder head 2, and each exhaust. It includes a merging pipe portion 10B that communicates with each other at the ends of the branch pipes 10A, an exhaust outlet portion 10C, a gas outlet portion 10D, and an EGR passage portion 10E. The exhaust manifold 10 is made of cast iron, and a plurality of bolt holes 10h are mainly formed in each exhaust branch pipe 10A.

The exhaust gas discharged from the cylinder head 2 to the four exhaust branch pipes 10A is merged at the merging pipe portion 10B, and a part thereof is EGR from the gas outlet portion 10D formed at the front end portion of the merging pipe portion 10B. It flows to the cooler 11, and the remaining exhaust gas flows from the exhaust outlet portion 10C to the supercharger 12. The gas lead-out portion 10D and the EGR passage portion 10E are formed with front and rear flange portions 22 and 23 for bolting and connecting the EGR cooler 11.

Each exhaust branch pipe 10A has a pair of bolt holes 10h and 10h, and a mounting flange 10f for mounting on the cylinder head 2 is formed. The fourth exhaust branch pipe 10A at the end is formed on a large mounting flange 24 having three bolt holes 10h in order to exert a function of bolt-connecting the EGR passage portion 10E to the gas passage portion 2A (described later). There is. In FIG. 5, a connecting meat portion 10m is formed by connecting adjacent mounting flanges 10f, 10f (or 24) back and forth to contribute to improvement in strength and composition, but the connecting meat portion 10m is omitted. The mounting flanges 10f and 24 may be independent of each other.

The exhaust gas of the gas lead-out portion 10D passes through the EGR cooler 11 and the EGR passage portion 10E as EGR gas, and flows to the gas passage portion 2A (see FIG. 3) formed at the rear end portion of the cylinder head 2. The EGR gas that has passed through the gas passage portion 2A is returned to the intake passage such as the intake manifold 14. The exhaust gas that has passed through the supercharger 12 is sent to the exhaust treatment device 5 through the exhaust duct 16.

As shown in FIGS. 4 to 6, the exhaust outlet portion 10C to the turbocharger 12 is located at a position other than the central portion in the longitudinal direction (front-rear direction) of the merging pipe portion 10B, in detail, the third from the front. It is provided so as to match the position of the third exhaust branch pipe 10A. The exhaust outlet portion 10C is taken out from the merging pipe portion 10B in a direction intersecting the longitudinal direction (leftward direction), and is formed in a state of having a detour shape curved in the front-rear direction.

Each exhaust branch pipe 10A and the branch pipe passage 10a which is an internal passage thereof extend in the left-right direction, and the merging pipe portion 10B and the merging passage 10b which is an internal passage thereof extend in the front-rear direction. The exhaust outlet portion 10C has an exhaust outlet that is approximately curved so as to change its direction from the left-right direction of the outlet from the confluence pipe portion 10B to the diagonal direction extending from the upper right to the lower left of the outlet flange 19 connected to the exhaust introduction portion 12C. The passage 10c is internally formed.

The axis 20p of the exhaust outlet passage 10c at the merging start end 20, which is the outlet point from the merging pipe 10B in the exhaust outlet 10C, and the axis 19p of the exhaust outlet passage 10c at the outlet flange 19 are about 120 to. The exhaust outlet passage 10c is curved so as to intersect at an intersection angle θ of 130 degrees (example: 124 degrees). The axis 20p at the merging start end is also the axis of the third branch pipe passage 10a.

The outlet flange 19 is formed with female threaded portions 18 at three locations, front left, rear left, and middle right, and an exhaust outlet passage 10c is formed so as to avoid the female threaded portion 18 in the middle right below and forward. That is, a female screw portion 18 for bolting the exhaust introduction portion 12C of the turbocharger 12 is formed in the exhaust outlet portion 10C, and the exhaust outlet passage 10c formed in the exhaust outlet portion 10C bypasses the female screw portion 18. It is formed in a curved shape.

The width of the portion 21 of the exhaust outlet passage 10c that bypasses the female screw portion 18 in the direction of intersecting the detour direction (front-rear direction) is expanded. Here, the "detour direction" is a direction (vertical direction, left-right direction, etc.) along a virtual vertical surface extending horizontally and vertically including the axial center 20p at the merging start end and the axial center 19p at the exit flange. An example of a direction that intersects the virtual vertical plane is the front-back direction as an orthogonal direction.

As shown in FIG. 5, in order to expand the width of the detour portion 21, specifically, a large angle R is provided at the boundary between the merging passage 10b and the exhaust outlet passage 10c formed in the merging pipe portion 10B. It is composed of things. Since the vertical length of the detouring portion 21 is compressed by the presence of the female screw portion 18, it is a means for eliminating (or suppressing) the reduction in cross-sectional area by expanding the left-right width more than the other portions.

By connecting the merging passage 10b and the exhaust outlet passage 10c with a large angle R, the front-rear width of the detouring portion 21 in the exhaust outlet portion 10C is substantially expanded, and the cross-sectional area can be secured. As the width expanding means, a configuration may be adopted in which the dimension itself of the front-rear width of the detour portion 21 is set to be larger than that of the other portions.

As shown in FIG. 5, of the merging pipe portion 10B and the merging passage 10b extending in the front-rear direction, the portion between the third exhaust branch pipe 10A, which is the third from the front, and the fourth exhaust branch pipe 10A, which is the rearmost portion. Is a diagonal passage 10n on the right as it goes later. Due to restrictions on the arrangement space, the fourth exhaust branch pipe 10A can be shortened and compactly configured without interference with the EGR passage portion 10E.

[About action and effect]
The exhaust outlet portion 10C is taken out from the confluence pipe portion 10B in a direction (left-right direction) intersecting the longitudinal direction (front-rear direction), and the exhaust outlet passage 10c is turned from left to diagonally upward to the right by about 120 degrees. It is formed in a state having a detour shape curved so as to be.

According to this configuration, the length of the exhaust outlet passage 10c can be made longer than that in the case where it is not curved. Therefore, even if the exhaust outlet portion 10C is located in the longitudinal direction of the confluence pipe portion 10B other than the central portion, each It is possible to suppress variations in the passage length from the exhaust branch pipe to the supercharger in the cylinder. As a result, it is possible to realize a comprehensively improved exhaust manifold for an engine with a supercharger so that it can be arranged in a narrow space and can be made compact while eliminating or suppressing exhaust interference.

The exhaust outlet passage 10c formed in the exhaust outlet portion 10C is formed in a curved shape so as to bypass the female thread portion 18 in the middle right. Therefore, while effectively utilizing the space inside the curve for the placement space of the mounting means of the turbocharger 12, the start end portion and the end portion of the exhaust outlet portion 10C are connected by the female screw portion 18 to enhance the strength and rigidity. There is an advantage that it becomes a rational structure that makes it possible.

Since the width of the portion 21 of the exhaust outlet passage 10c that bypasses the female screw portion 18 is expanded in the direction of intersecting the detour direction (front-rear direction), the cross-sectional area of the exhaust outlet passage 10c can be reduced due to the detour. It can be eliminated or suppressed. Therefore, although the curved exhaust outlet portion 10C tends to be disadvantageous in terms of the arrangement space, there is an advantage that a decrease in cross-sectional area can be suppressed and a smooth flow of exhaust gas can be ensured.

If the width of the detour portion 21 is expanded by providing an angle R at the boundary between the merging passage 10b and the exhaust outlet passage 10c formed in the merging pipe portion 10B, the exhaust outlet is extended from the merging passage 10b. There is an advantage that the above-mentioned "smooth exhaust gas flow" can be realized while smoothing the flow of exhaust gas to the passage 10c.

In an in-line 4-cylinder engine, there is a take-out point 20 on the extension line of the second or third exhaust branch pipe 10A, and the take-out point 20 from the merging pipe portion 10B of the exhaust outlet portion 10C is a plurality of exhaust branch pipes 10A. A configuration can be adopted in which the configuration is arranged on any of the extension lines. Therefore, in terms of combustion timing in a plurality of cylinders, for example, in the case of four cylinders, the first cylinder and the third cylinder are likely to interfere with each other, and the exhaust interference is the same as when the exhaust passage length (exhaust port length) is extended. It becomes possible to obtain the suppressing effect of.

Of both ends of the merging pipe portion 10B, the gas outlet portion 10D for EGR is provided at the end portion (front end portion) on the far side in the longitudinal direction of the exhaust manifold 10 with reference to the exhaust outlet portion 10C. A well-balanced exhaust manifold 10 has been realized in which most of the exhaust gas can be smoothly sent to the supercharger and the exhaust gas for EGR can be taken out well.

[Another Embodiment]
In an in-line 6-cylinder engine with a supercharger, a configuration in which a curved exhaust outlet to the supercharger is provided on an extension of the third or fourth exhaust branch pipe, or an in-line 3-cylinder engine with a supercharger It may be an exhaust manifold in which a curved exhaust outlet passage is arranged between the first and the second, or between the second and the third.
The present invention is also applicable to an exhaust manifold having a structure in which there is substantially no exhaust branch pipe 10A (box-type exhaust manifold) or almost no exhaust branch pipe 10A.

10 Exhaust manifold 10A Exhaust branch pipe 10B Confluence pipe 10C Exhaust outlet 10D Gas outlet 10b Exhaust confluence 10c Exhaust outlet passage 12 Supercharger 12C Exhaust introduction 18 Female thread 20 Take-out point 21 Detour

Claims (7)

It has a plurality of exhaust branch pipes connected to each exhaust port and a merging pipe portion that communicates the ends of the merging pipes with each other, and supercharges the merging pipe portion at a position other than the central portion in the longitudinal direction. An exhaust outlet to the machine is provided,
The exhaust outlet portion is an exhaust manifold for an engine with a supercharger, which is taken out from the confluence pipe portion in a direction intersecting the longitudinal direction thereof and is formed in a state of having a curved detour shape. A female screw portion for bolting the exhaust introduction portion of the turbocharger is formed in the exhaust outlet portion, and an exhaust outlet passage formed in the exhaust outlet portion is formed in a curved shape that bypasses the female screw portion. The exhaust manifold for an engine with a supercharger according to claim 1. The exhaust manifold for an engine with a supercharger according to claim 2, wherein a portion of the exhaust outlet passage that bypasses the female thread portion has an expanded width in a direction that intersects the detour direction. The supercharging according to claim 3, wherein the width of the detour portion is expanded by providing an angle R at a boundary between the exhaust merging passage formed in the merging pipe portion and the exhaust outlet passage. Exhaust manifold for machined engines. The supercharger according to any one of claims 1 to 4, wherein the exhaust outlet portion is taken out from the confluence pipe portion on an extension line of any one of the plurality of exhaust branch pipes. Exhaust manifold for engine with. The exhaust manifold for an engine with a supercharger according to claim 5, wherein four of the exhaust branch pipes are lined up and the take-out point is provided on an extension line of the second or third exhaust branch pipe. The supercharging according to any one of claims 1 to 6, wherein a gas outlet portion for EGR is provided at an end portion of both ends of the confluence pipe portion on the far side with respect to the exhaust outlet portion. Exhaust manifold for machined engines.

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