JP7260466B2 - industrial engine exhaust manifold and industrial engine - Google Patents

Description

TECHNICAL FIELD The present invention relates to an industrial engine such as a diesel engine mounted on an agricultural tractor or a backhoe and an exhaust manifold used therein, and more particularly to the exhaust manifold of the industrial engine and the industrial engine.

With stricter exhaust gas regulations, the number of engines adopting an EGR (Exhaust Gas Recirculation) system is increasing. That is, it is a device that extracts part of the exhaust gas from the exhaust manifold and returns it to the intake passage through a dedicated EGR passage, which is disclosed in Patent Document 1 and the like.

Usually, as disclosed in Patent Document 1, the EGR passage generally has a structure called "external EGR", which is configured in a passage component separate from the exhaust manifold and the engine body (cylinder head). be.

Problems with external EGR are as follows. That is, when the EGR passage (path) is provided, the heat source of the EGR passage is added to the exhaust manifold which is on the high temperature side. Therefore, there is a problem that the structure around the exhaust manifold and the external EGR is densely packed, and engine accessories such as the starter mechanism are easily damaged by the heat.

Japanese Patent Application Laid-Open No. 2005-291002

An object of the present invention is to reduce the temperature by introducing cooling air to the engine auxiliary equipment arranged on the side of the exhaust manifold, which tends to be subject to high temperature conditions, by devising a structure focusing on the exhaust manifold, which has a relatively large margin of strength. To provide an industrial engine and an exhaust manifold for an industrial engine which are improved so that engine accessories are less likely to fail and reliability is improved.

The present invention provides an exhaust manifold for an industrial engine,
An exhaust manifold for an industrial engine comprising a cooling fan on a first side that is one end side in the front-rear direction,
arranged on a second side that is one end side of a lateral direction that intersects the longitudinal direction in the industrial engine;
a plurality of exhaust inlet portions corresponding to a plurality of exhaust ports of the industrial engine ; one exhaust outlet portion; and an exhaust merging portion for collecting exhaust gas from the plurality of exhaust inlet portions and sending the exhaust gas to the exhaust outlet portion. and
It has an EGR lead-out passage with one end communicating with the exhaust junction and the other end opened, a gas lead-out portion formed at one end in the longitudinal direction of the exhaust junction, and an EGR passage with openings at both ends. An EGR passage portion is formed at the other end portion in the longitudinal direction of the exhaust confluence portion,
The gas lead-out portion and the EGR passage portion are provided with a mounting portion capable of mounting an EGR passage member positioned directly below the exhaust junction portion and connecting the EGR lead-out passage and the EGR passage,
The mounting portion of the EGR passage portion is formed as a flange portion that protrudes outward from the second side and continues from the exhaust confluence portion,
The cooling air directed from the first side toward the other end side in the front-rear direction is guided by the flange portion to an engine accessory located directly below the EGR passage portion .

In this case, it is convenient for the guide portion to be constituted by an EGR passage portion formed in the exhaust confluence portion for sending EGR gas toward the intake passage.

Regarding the present invention, refer to claims 2 to 8 for characteristic configurations and means other than the above-described configurations (means).

According to the present invention, since the guide portion that guides the cooling air to the engine accessories is formed in the exhaust manifold, the cooling air flowing in the vicinity of the exhaust manifold is directed by the guide in the direction in which the engine accessories exist (such as below). By changing, it becomes possible to promote the flow to the engine accessories. In other words, the cooling air can be accelerated by the guide, and the engine accessory located at a position where it is likely to be overheated can be efficiently air-cooled.

As a result, cooling air is directed to the engine accessories located on the side of the exhaust manifold, which are prone to high temperature conditions, to lower the temperature. An industrial engine exhaust manifold can be provided, as well as an industrial engine.

Front view of diesel engine with EGR Left side view of the engine of FIG. Rear view of the engine of Figure 1 Left side view of exhaust manifold Cross-sectional plan view of the exhaust manifold cut horizontally at the confluence pipe and viewed from above Cross-sectional rear view of the exhaust manifold cut vertically at the exhaust outlet and viewed from the rear Right side view of exhaust manifold Partial cutaway perspective view of the rear part of the exhaust manifold cut vertically and viewed from the side Enlarged side view of essential parts showing an exhaust manifold and an EGR cooler Schematic diagram showing the flow of cooling air near the rear of the exhaust manifold

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of an industrial engine and its exhaust manifold according to the present invention will be described below with reference to the drawings for an industrial diesel engine suitable for agricultural tractors and the like and its exhaust manifold.

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of an exhaust manifold for an engine with EGR according to the present invention will be described below with reference to the drawings for an exhaust manifold for an industrial diesel engine suitable for agricultural tractors and the like.

1 to 3 show an in-line 4-cylinder diesel engine with EGR (hereinafter simply referred to as the engine) E. As shown in FIG. In this engine E, a cylinder head 2 is assembled on a cylinder block 1 and a 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 (driving pulley) 6, a water pump 7, etc. are arranged on the front side of the engine E, and a flywheel 8 is arranged on the rear side. An exhaust manifold 10, an EGR cooler 11, a supercharger 12, an oil filter 13, and the like are arranged on the left side of the engine E, and an intake manifold 14, an oil level gauge 15, and the like are arranged on the right side.

As shown in FIG. 2, an exhaust manifold 10 is bolted to the left side surface of the cylinder head 2, and an exhaust outlet 10C of the exhaust manifold 10 is bolted to an exhaust introduction portion 12C of the supercharger 12. are connected by In addition, an EGR cooler 11 is arranged directly below the exhaust manifold 10 in a forward-backward posture in which both ends are supported by the exhaust manifold 10 . The supercharger 12 is a turbocharger having a turbine 12B with an exhaust introduction section 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 respective exhaust ports p1, p2, p3, and p4 of the cylinder head 2, and each exhaust branch pipe 10A. It is configured to have a confluence pipe portion 10B that communicates the ends of the branch pipes 10A with each other, an exhaust outlet portion 10C, a gas lead-out portion 10D, and an EGR passage portion 10E. The exhaust manifold 10 is made of cast iron and has a plurality of bolt holes 10h formed mainly in each exhaust branch pipe 10A.

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

Each exhaust branch pipe 10A is formed with a mounting flange 10f for mounting to the cylinder head 2 having a pair of bolt holes 10h, 10h. The rearmost fourth exhaust branch pipe 10A is formed in a large mounting flange 24 having three bolt holes 10h in order to exhibit the function of bolt-connecting the EGR passage portion 10E to the terminal side EGR passage portion 2A (described later). It is In FIG. 5, a connecting meat portion 10m is formed that can contribute to improvement in strength and composition by connecting the adjacent mounting flanges 10f, 10f (or 24) in the front-rear direction. The mounting flanges 10f and 24 may be independent of each other.

Exhaust gas from the gas lead-out portion 10D passes through the EGR cooler 11 and the EGR passage portion 10E as EGR gas, and flows into the end side EGR 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 terminal side EGR passage portion 2A is returned to the intake passage such as the intake manifold 14. As shown in FIG. Exhaust gas that has passed through the turbocharger 12 is sent to the exhaust treatment device 5 through an exhaust duct 16 .

As shown in FIGS. 4 to 7, the exhaust outlet portion 10C to the supercharger 12 is located at a position other than the central portion in the longitudinal direction (front-rear direction) of the confluence pipe portion 10B, more specifically, at the third position 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 confluence pipe portion 10B in a direction (left direction) that intersects the longitudinal direction thereof, and is formed in a curved detour shape when viewed in the front-rear direction.

Each of the exhaust branch pipes 10A and the branch pipe passage 10a as its internal passage extends in the left-right direction, and the confluence pipe portion 10B and its internal passage 10b extend in the front-rear direction. The exhaust outlet portion 10C has an approximately curved exhaust outlet that extends diagonally from the upper right to the lower left of the outlet flange 19 connected to the exhaust introduction portion 12C from the left and right direction of the extraction point from the confluence pipe portion 10B. A passageway 10c is formed therein.

The axial center 20p of the exhaust outlet passage 10c at the junction starting end 20, which is the extraction point from the joint pipe portion 10B in the exhaust outlet portion 10C, and the axial center 19p of the exhaust outlet passage 10c at the outlet flange 19 are approximately 120 to 120 degrees. The exhaust outlet passage 10c is curved so as to intersect at an intersection angle θ of 130 degrees (eg, 124 degrees). The axis 20p at the confluence starting 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, the left front, the left rear, and the right middle, and an exhaust outlet passage 10c is formed so as to avoid the female threaded portion 18 at the right center below and in front of it. That is, the exhaust outlet portion 10C is formed with a female screw portion 18 for bolting the exhaust introduction portion 12C of the turbocharger 12, 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.

A portion 21 of the exhaust outlet passage 10c that bypasses the female screw portion 18 has an increased width in a direction intersecting the bypass direction (front-rear direction). Here, the "detour direction" is a direction along an imaginary vertical plane extending left, right, up and down including the axis 20p at the confluence starting end and the axis 19p at the outlet flange (vertical direction, horizontal direction, etc.). , and an example of a direction that intersects the imaginary vertical plane is the front-rear direction as an orthogonal direction.

As shown in FIG. 5, the expansion of the width of the detouring portion 21 is achieved by forming a large angle R at the boundary between the confluence passage 10b formed in the confluence pipe portion 10B and the exhaust outlet passage 10c. It is composed by Since the detouring portion 21 is compressed in its vertical length due to the presence of the female screw portion 18, it is a means for eliminating (or suppressing) the reduction in cross-sectional area by widening the lateral width more than the other portions.

By connecting the confluence passage 10b and the exhaust outlet passage 10c at a large angle R, the front-to-rear width of the detouring portion 21 in the exhaust outlet portion 10C is substantially expanded, making it possible to secure a cross-sectional area. As a means for expanding the width, a configuration may be adopted in which the front-to-rear width of the detouring portion 21 itself is set 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 part. is an oblique passage 10n that is turned to the right as it goes to the rear. Due to restrictions on arrangement space, the fourth exhaust branch pipe 10A can be shortened to achieve a compact configuration without interference with the EGR passage portion 10E.

Next, the exhaust manifold 10, the EGR cooler 11, etc. will be described. As shown in FIGS. 4 to 9, the EGR passage portion 10E is formed at the rear end portion (an example of one longitudinal end portion) of the junction pipe portion (an example of the exhaust junction portion) 10B. A gas lead-out portion 10D for extracting EGR gas is formed at the front end portion (an example of the other end portion in the longitudinal direction) of 10B. An exhaust branch pipe (an example of an exhaust inlet portion) 10A, a junction pipe portion 10B, an exhaust outlet portion 10C, and an EGR passage portion 10E are integrally formed of cast iron material. That is, the exhaust manifold 10 is made of cast iron.

As shown in FIGS. 4, 5, 7 and 9, the gas lead-out portion 10D has a 1/4 arcuate opening at the intersection of the front end of the confluence passage 10b and the terminal end (left end) of the first branch pipe passage 10a. An EGR lead-out path 10d is formed downward on the front left side. A portion where the EGR lead-out path 10d opens downward is formed in a front flange portion (an example of a mounting portion) 22 .

The front flange portion 22 has two round holes (not shown) for bolting, and has a downward horizontal contact surface 22a. The position of the left end of the gas lead-out portion 10D is set to the same extent as the position of the left end of the exhaust outlet portion 10C or slightly to the right (inward) (see FIG. 5). The diameter (cross-sectional area) of the EGR lead-out path 10d is smaller than the diameter (cross-sectional area) of the branch pipe passage 10a.

As shown in FIGS. 4 to 9, the EGR passage portion 10E is formed with a curved EGR passage 10e between the forward-facing inlet opening 25 of the rear flange portion 23 and the right-facing outlet opening 26 of the large mounting flange 24. It is The inlet opening 25 is positioned below and to the left of the confluence pipe portion 10B, and the outlet opening 26 is positioned just behind the fourth branch pipe passage and slightly below. Therefore, the EGR passage portion 10E and the EGR passage 10e are formed as oblique passages that change direction at two points, the front end portion and the rear end portion.

The large mounting flange 24 has a substantially trapezoidal connecting surface 24a with a wide bottom and a right-facing vertical surface 24a, and a total of three bolt holes 10h, one on the top and two on the bottom. The bolt hole 10h on the front lower side is vertically intermediate between the EGR start end portion 27 on the front side of the EGR passage portion 10E and the confluence pipe portion 10B, and is located in both the EGR passage 10e and the confluence passage 10b (oblique passage 10n). It can be installed in a position that does not interfere. Also, the seat hole 28 of the bolt hole 10h on the lower front side has a diameter that allows a general bolt turning tool (such as a socket wrench socket) to be used without problems.

As shown in FIGS. 5 and 9 , the EGR cooler (an example of the EGR passage member) 11 has support flanges 29 and 30 at the front and rear ends, and a gap between the front support flange 29 and the rear support flange 30 . A large EGR passage (not shown) is formed inside. An elbow pipe 31 is barely attached to the front support flange 29. The elbow pipe 31 is bolted to the front flange portion 22, and the rear support flange 30 is attached to the rear flange portion 23 through screw holes 23a, 23a ( (see FIG. 8).

The elbow pipe 31 is a 90-degree bent pipe having a front mounting flange 31A, a rear mounting flange 31B, and an elbow pipe body 31C made of pipe material. The front mounting flange 31A is bolted to the front flange portion 22, and the rear mounting flange 31B is bolted to the front support flange 29. As shown in FIG. That is, the EGR gas (exhaust gas) from the gas lead-out portion 10D of the exhaust manifold 10 enters the EGR cooler 11 through the elbow pipe 31, and the EGR gas cooled to some extent in the EGR cooler 11 passes through the EGR passage portion 10E. , to the gas passage 2a (see FIG. 5) of the terminal side EGR passage portion 2A of the cylinder head 2. As shown in FIG.

The EGR cooler 11 has an elongated shape that is long in the front-rear direction, and has appropriate clearances between the upper and lower sides of the exhaust manifold 10 and the left and right sides of the cylinder head 2 . Therefore, the rearward cooling air w generated by the cooling fan 32 (see FIG. 2) provided in the front part of the engine flows well near the surface of the EGR cooler 11, thereby exhibiting a good air cooling effect.

As shown in FIGS. 9 and 10, the exhaust manifold 10 is formed with a guide portion G that guides the cooling air w from the cooling fan 32 (see FIG. 2) to the starter mechanism (starter, cello) 33, which is the engine accessory A. It is The guide portion G is composed of an EGR passage portion 10E formed in the junction pipe portion 10B for sending EGR gas toward the intake passage.

A starter mechanism 33 for starting the engine is provided at the rear of the left side of the engine E and in front of the flywheel 8 . The starter mechanism 33 is located below the rear portion of the EGR cooler 11 and is a place where the thermal load is large. The EGR passage portion 10</b>E of the exhaust manifold 10 protrudes greatly obliquely downward (diagonally downward to the left) from the junction pipe portion 10</b>B and is positioned just above the starter mechanism 33 .

Therefore, of the rearward cooling airflow w generated by the rotation of the cooling fan 32, the cooling airflow w flowing near the exhaust manifold 10 and the EGR cooler 11 is generated by the EGR passage portion 10E projecting laterally downward, particularly the rear flange portion. 23 to facilitate flow to the starter mechanism 33 . That is, as shown in FIG. 10, the EGR passage portion 10E functions as a guide portion G, and the temperature of the starter mechanism 33, which is the engine auxiliary machine A that easily overheats, is effectively lowered by the cooling air w.

The front lower bolt hole 10h of the large mounting flange 24 is located between the EGR starting end 27 of the EGR passage 10E and the exhaust confluence 10B as described above. There is nothing to block, and there is a good point that the bolt and nut can be turned without problems. In addition, there is also the advantage that a good heat dissipation effect can be expected from the seat hole 28 which is in a state of being open on the left side. There is also the advantage that the heat trapped during dead soaking is easily discharged (heated) from the seat hole (tool path hole) 28 .

As shown in FIGS. 4, 5, 8, and 10, a tubular EGR passage 10e is formed inside the EGR passage portion 10E, and the contour shape of the EGR passage portion 10E is a curved surface conforming to the shape of the EGR passage 10e. Therefore, it can be expected that the cooling air w passing through the vicinity thereof flows more smoothly and efficiently.

In addition, as shown in FIGS. 4, 5 and 8, the EGR passage portion 10E has a rearwardly constricted shape as a whole, so that the exhaust air after cooling the starter mechanism 33 and the like flows more smoothly rearward. Since it can flow, there is also an advantage that the air-cooling action of the starter mechanism 33 by the cooling air w is accelerated from this point.

[About other effects]
The EGR passage portion 10E is formed at the rear end portion, which is one longitudinal end portion of the confluence pipe portion 10B, and is provided at the front end portion, which is the other longitudinal end portion of the confluence pipe portion 10B, for extracting EGR gas. is formed. Therefore, an external EGR passage (external EGR) such as the EGR cooler 11 can be provided between the gas lead-out portion 10D and the starting end portion of the EGR passage portion 10E, thereby improving the degree of freedom in design.

Mounting portions 22 and 23 for mounting the EGR cooler 11 (EGR passage member 11) connecting the gas lead-out portion 10D and the EGR passage portion 10E are provided at the starting ends of the gas lead-out portion 10D and the EGR passage portion 10E. It is convenient because the attachment and detachment of the cooler 11 is facilitated. The attachment portion 23 of the EGR passage portion 10E is a flange portion for bolting the EGR passage member 11, and if the flange portion 23 is continuous with the confluence pipe portion 10B, the strength and rigidity of the EGR passage portion 10E are increased. It is convenient to improve.

[Another embodiment]
A vane-shaped guide may be provided in the EGR passage portion 10E for more positively guiding the cooling air w downward.
The present invention is also applicable to an exhaust manifold having a structure in which the exhaust branch pipe (exhaust inlet portion) 10A is substantially short or absent (box type exhaust manifold). In the case of a box-type exhaust manifold with one opening covering multiple exhaust ports in the cylinder head, the exhaust branch (exhaust inlet) 10A is one of the large openings. Also, in the box-type exhaust manifold, the junction pipe portion 10B is one large exhaust junction portion.

2 cylinder head 10 exhaust manifold 10A exhaust inlet (exhaust branch pipe)
10B Exhaust junction (junction pipe)
10C exhaust outlet portion 10D gas lead-out portion 10E EGR passage portion
10d EGR lead-out path
10e EGR passage 10h Bolt hole 11 EGR passage member (EGR cooler)
22 Mounting part (front flange part)
23 Mounting part (rear flange part)
25, 26 opening 33 starter mechanism A engine accessory
E. Industrial engine
G Guide part
p1 to p4 Exhaust port
w Cooling air

Claims (8)

An exhaust manifold for an industrial engine comprising a cooling fan on a first side that is one end side in the front-rear direction,
arranged on a second side that is one end side of a lateral direction that intersects the longitudinal direction in the industrial engine;
a plurality of exhaust inlets corresponding to a plurality of exhaust ports of the industrial engine ; one exhaust outlet; exhaust gases from the plurality of exhaust inlets are collectively sent to the exhaust outlet; A confluence section is provided, and
It has an EGR lead-out passage with one end communicating with the exhaust junction and the other end opened, a gas lead-out portion formed at one end in the longitudinal direction of the exhaust junction, and an EGR passage with openings at both ends. An EGR passage portion is formed at the other end portion in the longitudinal direction of the exhaust confluence portion,
The gas lead-out portion and the EGR passage portion are provided with a mounting portion capable of mounting an EGR passage member positioned directly below the exhaust junction portion and connecting the EGR lead-out passage and the EGR passage,
The mounting portion of the EGR passage portion is formed as a flange portion that protrudes outward from the second side and continues from the exhaust confluence portion,
An exhaust manifold for an industrial engine that guides cooling air flowing from the first side toward the other end side in the front-rear direction to an engine accessory located directly below the EGR passage through the flange portion . The industry according to claim 1, wherein a tubular EGR passage is formed inside the EGR passage portion, and the contour shape of the EGR passage portion is set to a shape having a curved surface that conforms to the shape of the EGR passage. engine exhaust manifold. 3. The exhaust manifold for an industrial engine according to claim 1, wherein a bolt hole for bolting the exhaust inlet portion to the cylinder head is formed between the EGR passage portion and the exhaust junction portion. The EGR passage portion is formed at one end in the longitudinal direction of the exhaust junction, and a gas lead-out portion for extracting EGR gas is formed at the other end in the longitudinal direction of the exhaust junction. 4. The industrial engine exhaust manifold according to claim 2 or 3. 5. The exhaust manifold for an industrial engine according to claim 4, wherein a mounting portion for mounting an EGR passage member connecting said gas lead-out portion and said EGR passage portion is provided at the starting end portion thereof. An industrial engine comprising an industrial engine exhaust manifold according to any one of claims 1-5 . 7. The industrial engine of claim 6, wherein said engine accessory is a starter mechanism . The industrial engine according to claim 6 or 7, wherein said EGR passage member is an EGR cooler .

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