WO2016121482A1

WO2016121482A1 - Intake port structure for engine

Info

Publication number: WO2016121482A1
Application number: PCT/JP2016/050651
Authority: WO
Inventors: 遼森岡; 智吉川; 義幸干場
Original assignee: 三菱自動車工業株式会社
Priority date: 2015-01-29
Filing date: 2016-01-12
Publication date: 2016-08-04
Also published as: CN107208569B; CN107208569A; JP6561480B2; JP2016138534A

Abstract

Tumble flow in a fuel chamber is strengthened without complicating structure. An intake port structure for an engine has an intake port (5) of an engine which is continuous with the upstream side of the inner surface of an annular seat ring (20) in the intake port (5), the inner surface of the intake port is provided with an inner-surface-matching part (32) that, in plan view along the axial direction of the seat ring (20) from a combustion chamber (3) side, is flush with the inner surface of the seat ring (20) on the rear end side farther from the axial center of a cylinder bore, and any other portion is provided with a projecting part (31) that protrudes farther inward than the inner surface of the seat ring (20).

Description

Engine intake port structure

The present invention relates to an intake port structure of an engine that enables good combustion in a combustion chamber.

Conventionally, tumble flow (longitudinal vortex), which is a swirling flow flowing along the axial direction of the cylinder bore, or swirl flow, which is a swirling flow flowing along the circumferential direction of the inner peripheral surface of the cylinder bore, in the combustion chamber of the engine Various techniques for generating vortices) are known.

As a technique for generating tumble flow, for example, there is a technique for changing the degree of shielding in the intake port by an intake flow control valve provided in the intake port to generate tumble flow (for example, Patent Document 1 below) reference). In addition, there is also a nozzle that generates tumble flow by ejecting air downward along a wall surface of a valve throat from a nozzle provided in an intake port (for example, see Patent Document 2 below).

Furthermore, in order to strengthen tumble flow, there is a technique of reducing the inner diameter of the intake port and providing an edge portion on the inner surface of the intake port on the side far from the axial center of the cylinder bore. By providing the edge portion, the flow passage cross-sectional area is reduced, and the tumble flow can be strengthened by increasing the flow velocity (see, for example, Patent Document 3 below).

Japanese Patent Application Publication No. 2007-32560 JP, 2013-122188, A JP-A-2007-46457 (page 3 specification paragraph 0010, page 8 see FIG. 6)

As described above, in the case of generating an intake tumble flow in the fuel chamber, there is a demand to further strengthen the tumble flow in order to ensure good combustion. However, the addition of various valve devices and nozzles in order to enhance tumble flow is limited because it leads to complication of the device and increase in cost.

Further, according to the technology of Patent Document 3, since the intake passage is bent around the edge portion in the intake port, the flow coefficient may be reduced, and conversely, the tumble flow may be weakened.

Therefore, an object of the present invention is to strengthen tumble flow in the fuel chamber without complicating the structure.

In order to solve the above problems, the present invention comprises an intake port connected to a combustion chamber of an engine, and an annular seat ring provided in a region of the intake port facing the combustion chamber; The inner surface of the intake port continuing to the upstream side of the inner surface is the inner surface of the seat ring at the rear end side far from the axial center of the cylinder bore in a plan view along the axial direction of the seat ring from the combustion chamber side. A flared portion provided with a single inner surface matching portion and projecting to the inner side of the inner surface of the seat ring at any other portion, and the cross-sectional area of the flow path at the location where the flared portion is The engine intake port structure was made smaller than the cross-sectional area of the engine.

Here, the projecting portion is any one of side portions connecting the rear end side and the front end side close to the axial center of the cylinder bore among the inner surfaces of the intake port continuing to the upstream side of the inner surface of the seat ring A configuration provided on the side or both sides of the

Further, the inner surface matching portion may adopt a configuration provided on the front end side of the inner surface of the intake port continuing on the upstream side of the inner surface of the seat ring.

Alternatively, a protrusion is provided on the front end side, and a maximum protrusion length of the protrusion of the side portion inward from the inner surface of the seat ring is the inner length from the inner surface of the seat ring in the protrusion on the front end side. A configuration set larger than the maximum protrusion length can be adopted.

In each of these configurations, the inner surface of the intake port continuing on the upstream side of the inner surface of the seat ring has a maximum diameter in the front-rear direction connecting the front end side and the rear end side in the width direction orthogonal to that A configuration that is set larger than the maximum diameter can be adopted.

In each of these configurations, the inner surface of the intake port continuing on the upstream side of the inner surface of the seat ring has an arc-shaped portion around the axial center of the seat ring on the rear end side and the front end side, It is possible to adopt a configuration in which the radius of the arc-shaped portion on the rear end side is set larger than the radius of the arc-shaped portion on the front end side.

The present invention is characterized in that the inner surface of the intake port continued to the upstream side of the inner surface of the seat ring, and the seat ring on the rear end side far from the axial center of the cylinder bore in plan view along the axial direction of the seat ring from the combustion chamber side. Since the inner surface matching portion flush with the inner surface and the projecting portion protruding inward of the inner surface of the seat ring is provided at any other portion, the tumble ratio, that is, The rotational speed of the tumble flow can be improved while the piston reciprocates one time. As a result, the tumble flow in the fuel chamber can be enhanced without complicating the structure.

It is a principal part enlarged view which shows the intake port of embodiment of this invention. It is a modification of FIG. 1A. It is a graph which shows the effect of this invention. It is a principal part enlarged view which shows other embodiment. It is a principal part enlarged view which shows other embodiment. It is explanatory drawing which shows the processing method of an inlet port. It is explanatory drawing which shows the processing method of an inlet port. It is explanatory drawing which shows the completion time of an inlet port. It is a longitudinal cross-sectional view which shows the inside of an engine typically. It is a detail view of an intake port. It is a detail view of an intake port.

An embodiment of the present invention will be described based on the drawings. FIG. 1A is a main part enlarged view showing the vicinity of the intake port of the engine of this embodiment. FIG. 1B is a modification thereof.

The arrangement of the combustion chamber 3 of the engine and the shape of the intake port 5 are shown in FIGS. 5A to 5C. The engine of this embodiment is a diesel engine for automobiles. A piston 2 is accommodated in a cylinder 1 of the engine. A combustion chamber 3 is formed by the inner peripheral surface of the cylinder 1, the upper surface of the piston 2, and the like. An intake passage 5 for feeding intake air into the combustion chamber 3 of each cylinder, an exhaust port 7 drawn from the combustion chamber 3, and a fuel injection device 9 for injecting fuel into the combustion chamber 3 are provided.

In these drawings, members and means directly related to the present invention are mainly shown, and other members and the like are not shown. Further, although only one cylinder 1 is shown in the drawings, the engine may be a single cylinder or may be a multi-cylinder having a plurality of cylinders.

In this embodiment, as shown in FIG. 5C, the intake port 5 branches into two passages in front of the combustion chamber 3. Although not shown, the exhaust port 7 also branches into two passages in front of the combustion chamber 3.

An intake valve hole 5 a, which is an opening of each intake port 5 to the combustion chamber 3, is opened and closed by the intake valve 6. Further, exhaust valve holes 7 a, which are openings of the exhaust ports 7 to the combustion chamber 3, are opened and closed by the exhaust valve 8. At this time, the intake valve 6 and the exhaust valve 8 contact with and separate from an annular seat ring 20 provided in a region facing the combustion chamber 3 of the intake port 5 and the exhaust port 7, respectively.

The intake valve 6 and the exhaust valve 8 open and close the intake valve hole 5a and the exhaust valve hole 7a at a predetermined timing by the rotation of a camshaft provided on the cylinder head 4 side. The shaft portions of the intake valve 6 and the exhaust valve 8 are drawn out to the camshaft side in the cylinder head 4 from a shaft insertion portion 5 b opened to the inner surface of the intake port 5 and the exhaust port 7. As shown in FIG. 5B, the shaft insertion portion 5b of the intake port 5 opens at a bent portion 5c located on the upstream side of the intake valve hole 5a in the intake port 5, or immediately upstream of the bent portion 5c. .

As shown in FIG. 1A, of the inner surface of the intake port 5 continuous to the upstream side of the inner surface of the seat ring 20, the downstream side of the shaft insertion portion 5b supporting the shaft portion of the intake valve 6 and immediately above the seat ring 20 The portion (hereinafter referred to as the seat ring upstream portion 30) located on the side of the cylinder bore has a cylinder bore in a bottom view from the combustion chamber 3 side, that is, a plan view along the axial center direction of the seat ring 20 from the combustion chamber 3 side. At the rear end side far from the axial center x, an inner surface matching portion 32 flush with the inner surface of the seat ring 20 is provided. In this embodiment, the rear end portion 31 d of FIG. 1A corresponds to the inner surface matching portion 32.

In addition, the seat ring is provided on the other portion of the seat ring upstream portion 30, that is, on the front end side close to the axial center x of the cylinder bore in the plan view, and on both side portions connecting the front end side and the rear end side. A projecting portion 31 is provided which protrudes inward from the inner surface of 20. In this embodiment, the front end portion 31 c and the

side portions

31 a and 31 b of FIG. 1A correspond to the overhanging portion 31. The entire sectional shape of the seat ring upstream portion 30 has a so-called oval shape in which the maximum diameter in the front-rear direction connecting the front end side and the rear end side is set larger than the maximum diameter in the width direction orthogonal thereto. It has become.

In addition, each of the rear end portion 31 d and the front end portion 31 c is provided with an arc-shaped portion around the axial center of the seat ring 20. The

side portions

31a and 31b are linear inner surfaces connecting the rear end 31d and the front end 31c. The

side portions

31a and 31b may be in the shape of a gentle arc.

The cross-sectional area of the flow passage of the seat ring upstream portion 30 is smaller than the cross-sectional area of the flow passage of the seat ring 20 by the projecting portion 31. Thereby, the flow velocity of the intake air into the combustion chamber 3 can be increased.

Here, the overhanging portion 31 is not provided at the rear end portion 31 d of the seat ring upstream portion 30 which is far from the axial center x of the cylinder bore. The overhanging portion 31 is provided at a location excluding the rear end 31 d. As a result, the flow rate of intake can be increased by narrowing the flow path at the other portion, that is, the side provided with the overhang portion 31 while securing the flow rate of intake at the side close to the inner circumferential surface of the cylinder 1 . It has been confirmed by experiments that the tumble ratio can be improved by securing the flow rate at the rear end 31 d and improving the flow velocity on the other side.

Here, the seat ring upstream portion 30, that is, the inner surface of the intake port 5 continuing on the upstream side of the inner surface of the seat ring 20 is the inner surface of the seat ring 20 among the inner surfaces of the It means the part located immediately above. Further, the projecting portion 31 is provided to reduce the cross-sectional area of the flow passage in the intake port 5.
For this reason, even if the shaft insertion portion 5 b supporting the shaft portion of the intake valve 6 has a portion that protrudes to the inner surface of the intake port 5, it does not correspond to the overhang portion 31. Further, even if the inner surface of the bent portion 5c is seen from the inner surface of the seat ring 20 in the plan view, the inner surface of the bent portion 5c is not for reducing the cross-sectional area of the flow passage, It does not correspond to Part 31. The seat ring upstream portion 30 is located immediately above the seat ring 20, and usually is also a portion where the cross-sectional area of the flow path of the intake port 5 gradually spreads toward the combustion chamber 3.

A modification is shown in FIG. 1B. In FIG. 1B, the seat ring upstream portion 30 is the same as the above-described example in that the inner side matching portion 32 is provided at the rear end 31d and the projecting portion 31 is provided at the front end 31c and the

side portions

31a and 31b.

Moreover, the point which equips each of the back end part 31d and the front end part 31c with the arc-shaped part of the circumference of the axial center of the seat ring 20 is also the same. The same applies in that the

side portions

31a and 31b are linear inner surfaces connecting the rear end 31d and the front end 31c.

In this example, the radius rd of the circular arc portion of the rear end portion 31 d is set larger than the radius rc of the circular arc portion of the front end portion 31 c. Thus, relatively increasing the radius on the rear end portion 31d side is effective for securing the flow rate on the rear end side, and making the radius on the front end portion 31c side relatively small on the front end side It is effective in securing the flow velocity in

Thus, in the case where the projecting portion 31 is provided at the front end portion 31c, the maximum projecting lengths a and b of the projecting portions 31 of the

side portions

31a and 31b from the inner surface of the seat ring 20 are the same as those of the front end portion 31c. It is desirable to set the projection length 31 to be larger than the maximum inward projection length c from the inner surface of the seat ring 20. The amount of reduction of the flow passage cross-sectional area for improving the flow velocity can be secured larger at the

side portions

31a and 31b than at the front end 31c.

The effect of the tumble ratio improvement of this invention is shown in FIG. In the conventional engine, the flow rate and the tumble ratio are in a trade-off relationship, and there is a problem that when the flow rate is increased, the tumble ratio is decreased. However, according to the present invention, since the tumble ratio can be increased while the flow rate is increased, the trade-off relationship between the conventional flow rate and the tumble ratio can be improved.

Another embodiment is shown in FIG. 3A. In this aspect, the inner surface matching portion 32 is provided on the rear end portion 31d side in the plan view. In addition, an overhanging portion 31 is provided on the front end portion 31c and the

side portions

31a and 31b on both sides. However, the overhanging portions 31 of the

side portions

31a and 31b are not linear but are continuous with the arc-like overhanging portions 31 of the front end 31c only in the portion closer to the front end than the axial center o of the seat ring 20 An arcuate overhang 31 is provided. The arc-shaped overhanging portion 31 of the

side portions

31a and 31b and the arc-shaped overhanging portion 31 of the front end portion 31c are continuous circles having the same radius rc concentrically, these arcs having different radii. It may be Further, the area rc of the overhanging portion 31 may be increased by making the radius rc of the overhanging portion 31 smaller than the radius rd of the arc-shaped inner surface on the rear end portion 31d side.

Yet another embodiment is shown in FIG. 3B. In this aspect, the inner surface matching portion 32 is provided at the rear end portion 31 d and the front end portion 31 c. The overhanging portions 31 are provided on the

side portions

31a and 31b on both sides. Also in this embodiment, the cross-sectional shape of the seat ring upstream portion 30 is a so-called oval in which the maximum diameter in the front-rear direction connecting the front end side and the rear end side is set larger than the maximum diameter in the width direction orthogonal thereto. It is a shape.

In each of these embodiments, the overhanging portion 31 is provided on both

side portions

31a and 31b, but the overhanging portion 31 is provided only on one of the side portions and the other side portion is also used as the inner surface matching portion 32. Good.

Below, the manufacturing method (processing method) for setting it as the intake port structure of these each aspect is demonstrated.

The intake port 5 including the seat ring upstream portion 30 is manufactured together with the cylinder head 4 by casting. Since the cross-sectional shape of the seat ring upstream portion 30 is not a perfect circle due to the existence of the projecting portion 31 and the inner surface matching portion 32, the mold of the casting at the time of casting is made to have such a shape or The member is cut by a three-dimensional machining center or the like.

Next, the portion of the intake valve hole 5a where the intake valve 6 abuts is processed. The seat ring 20 before processing is press-fit into a portion of the intake port 5 facing the combustion chamber 3 in advance, and is fixed to the intake port 5.

First, in the first step, the throat portion 22 which is gradually expanded toward the combustion chamber 3 is processed on the inner surface of the deep portion of the intake valve hole 5a. As shown in FIG. 4A, the throat cutter A is caused to approach a predetermined amount into the intake port 5 along an axial center coinciding with the center line of the intake valve 6. By rotating the throat cutter A about the axis, the inner surface of the seat ring 20 and the upstream portion 30 of the seat ring are shaved. By processing the throat cutter A, a throat portion 22 formed of a conical surface, a spherical surface or the like is formed continuously from the inner surface of the seat ring 20 to the inner surface of the seat ring upstream portion 30. Therefore, at this time, a part of the overhanging portion 31 and the inner surface matching portion 32 is also cut.

Next, in the second step, after the throat cutter A is removed, the portion on which the intake valve 6 abuts, that is, the valve abutment portion 21 is processed. As shown in FIG. 4B, the sheet cutter B is advanced into the seat ring 20 along the axial center coincident with the center line of the intake valve 6 by a predetermined amount. The inner surface of the seat ring 20 is cut by rotating the sheet cutter B around the axis. By processing the sheet cutter B, the valve contact portion 21 formed of a conical surface or a spherical surface is formed on the inner surface of the seat ring 20.

As shown in FIG. 4C, the throat portion 22 and the valve contact portion 21 are smoothly continuous, so that a smooth inner surface is formed from the projecting portion 31 and the inner surface matching portion 32 to the inner surface of the seat ring 20. Be done.

The throat portion 22 may be processed earlier than the valve contact portion 21, and the valve contact portion 21 may be processed earlier than the throat portion 22.

In these embodiments, the configuration of the present invention has been described by taking a diesel engine for a car as an example. However, the present invention can be applied to a four-cycle gasoline engine for a car, other various applications, and various engines.

Reference Signs List 1 cylinder 2 piston 3 combustion chamber 4 cylinder head 5 intake port 6 intake valve 7 exhaust port 8 exhaust valve 9 fuel injection device 20 seat ring 21 valve contact portion 22 throat portion 30 seat ring upstream portion 31 overhang portion 32 inner surface matching portion

Claims

An intake port connected to the combustion chamber of the engine;
And an annular seat ring provided in a region of the intake port facing the combustion chamber,
The inner surface of the intake port continued to the upstream side of the inner surface of the seat ring is the seat ring on the rear end side far from the axial center of the cylinder bore in a plan view along the axial direction of the seat ring from the combustion chamber side An overhanging portion which is flush with the inner surface of the seat ring and has an overhanging portion projecting inward of the inner surface of the seat ring in any other portion, and the cross-sectional area of the flow passage at the location where the overhanging portion is Engine intake port structure smaller than the cross-sectional area of the ring flow path.
The projecting portion is any one of side surfaces connecting the rear end side and the front end side close to the axial center of the cylinder bore among the inner surfaces of the intake port continuing to the upstream side of the inner surface of the seat ring The engine intake port structure according to claim 1, provided on both sides.
The engine intake port structure according to claim 2, wherein the inner surface matching portion is provided on the front end side of an inner surface of an intake port continuing to an upstream side of an inner surface of the seat ring.
An overhanging portion is provided on the front end side,
The maximum inward projecting length from the inner surface of the seat ring in the projecting portion of the side portion is set larger than the inward projecting length from the inner surface of the seat ring in the projecting portion on the front end side The engine intake port structure according to claim 2.
The maximum diameter in the front-rear direction connecting the front end side and the rear end side of the inner surface of the intake port continuing on the upstream side of the inner surface of the seat ring is set larger than the maximum diameter in the width direction orthogonal thereto The engine intake port structure according to any one of claims 1 to 4.
The inner surface of the intake port continuing on the upstream side of the inner surface of the seat ring has an arc-shaped portion around the axial center of the seat ring on each of the rear end side and the front end side,
The engine intake port structure according to any one of claims 1 to 5, wherein the radius of the rear end side arcuate portion is set larger than the radius of the front end side arcuate portion.