JPS5813081Y2 - engine intake system - Google Patents

Description

[Detailed Description of the Invention] The present invention defines an intake passage in the cylinder head by a separation wall that is cast at the same time as the cylinder head, and a partition member that extends directly above the head of the intake valve in continuation with the separation wall. The present invention relates to an engine intake system that is separated into low-load and high-load intake ports, and in particular to an improvement in the mounting structure of a partition member.

Conventionally, this intake system has two independent intake passages, one for low load (-primary) and one for high load (secondary), in a single intake hole that opens into the engine's combustion chamber and is opened and closed by an intake valve. , so-called dual intake systems are generally well known.

This dual intake system has a low-load intake passage and a high-load intake passage that open directly above the head of the intake valve, and only uses the low-load intake passage during low and medium loads, including during idling. In addition to increasing the flow rate of the air-fuel mixture to promote vaporization and atomization of the fuel, the air-fuel mixture is also supplied from the high-load intake passage when the load is high, thereby improving output.

Compared to conventional intake systems consisting of a single intake passage, these dual intake systems can promote fuel vaporization and atomization at low loads, or use directional ports (intake air flows tangentially into the cylinder, It has various advantages such as improving combustion efficiency by strengthening the swirl inside the combustion chamber by combining an intake port that generates swirl inside the combustion chamber.

However, in the above-mentioned dual intake system, if the low-load intake passage and the high-load intake passage are not completely separated to just above the head of the intake valve in the fully closed state, the cylinder The air-fuel mixture that has flowed into the low-load intake passage of cylinder B other than A is supplied to the combustion chamber of cylinder A via the high-load intake passage of cylinder B and the high-load intake passage of cylinder A,
Since the flow velocity of the air-fuel mixture supplied to the combustion chamber of cylinder A is reduced, there is a drawback that the inherent advantages of the dual intake system cannot be fully utilized.

Therefore, in order to fully utilize the advantages of this multiple intake system, it is necessary to completely separate the low-load and high-load intake passages to eliminate interference between the cylinders.

One method for this purpose is to extend a separation wall that separates both passages to just above the head of the intake valve, and when the intake valve is closed, the head of the intake valve and the separation wall separate both passages ( JP-A-471504) has been proposed.

However, with the above method, it is difficult to control the gap between the head of the intake valve and the separation wall, which poses problems in terms of machining accuracy, and it is difficult to eliminate the gap at all, making complete separation impossible. Moreover, if the separation wall is formed by casting to the point directly above the head of the intake valve, the thickness of the separation wall cannot be kept below a certain limit, so the intake area cannot be made large, which increases intake resistance. There were some drawbacks.

In order to eliminate such drawbacks, the present applicant has provided independent low-load and high-load intake pipes, and has also created an air intake pipe that is cast at the same time as the cylinder head, so that the air in the intake passage is a separation wall that extends in an arc shape from the side opening to a position a set distance from the head of the intake valve installed in the combustion chamber side opening; The above-mentioned intake passage is separated into low-load and high-load intake ports by a partition member that extends in an arc shape to the opposite end face facing the combustion chamber side opening and extends directly above the head of the intake valve. An intake system for an engine is proposed in which the above-mentioned low-load and high-load intake pipes are respectively connected to a high-load intake port.

(For example, see Japanese Utility Model Application Publication No. 53-53208.

) According to this structure, the machining accuracy of the partition member can be made high, so the separation can be made perfect, and the thickness can be made sufficiently thin.
Although it is possible to generate a good swirl, especially at low load, without unnecessarily increasing the intake resistance, there is still room for improvement in the mounting structure of the partition member.

The present invention enables the partition member to be reliably fixedly supported, and specifically, the intake valve guide, which slidably supports the shaft portion of the intake valve, is placed on the combustion chamber side of the separation wall. The intake valve guide is made to protrude from the opposite end face facing the opening, and a fitting part provided on the partition member is fitted to the outer peripheral surface of the protruding part of the intake valve guide, so that the partition member is reliably supported by the intake valve guide. An object of the present invention is to provide an engine intake device equipped with a partition member mounting structure.

Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

In Figures 1 and 2, 1 is an intake manifold fixed to the cylinder head 2, 3 and 4 are for low load (-outlet) and high load (outlet) separated by a partition 5.
An intake pipe 6 is formed in the cylinder head 2 and has an intake hole 8.
The intake passage 6 is cast at the same time as the cylinder head 2, and continues from the atmosphere side opening 6a of the intake passage 6 to the above-mentioned partition wall 5. Head 14a of intake valve 14 attached to opening 6b
A separation wall 9 extends in an arc shape through the intake passage 6 to a position further away from the combustion chamber by a set distance, and an intake wall is inserted through the combustion chamber side opening 6b and continues to the opposite end surface 9a of the separation wall 9 facing the combustion chamber side opening 6b. A low-load pipe with a relatively small cross-sectional area communicates with the low-load intake pipe 3 and high-load intake pipe 4 through a partition member 10 extending in an arc shape through the intake passage 6 to just above the head 14a of the valve 14. It is separated into an intake port and a high-load intake port 12 having a relatively large cross-sectional area.

In addition, in the figure, 13 is an exhaust hole.

As shown in FIG. 2, the partition wall 9 formed in the cylinder head 2 has an opposing end surface 9a facing the combustion chamber side opening 6b.
is spaced a set distance from the head 14a of the intake valve 14 that opens and closes the intake hole 8, and has a shape that matches the trapezoidal upper edge 10a of the partition member 10 inserted from the combustion chamber side opening 6b. Form.

Further, the cylindrical intake valve guide 15 having an inner circumferential surface that slidably supports the shaft portion 14b of the intake valve 14 is connected to the partition wall 9.
Annular fitting portions 10b integrally formed at the centers of the four parts of the partition member 10 are fitted into the protruding portions 15a by a certain amount axially downward from the opposing end surfaces 9a of the intake valve guide. The upper part of the partition member 10 is fixed to 15.

As shown in FIGS. 3a and 3b, the partition member 10 has a fitting portion 1 having an annular upper portion in the vertical direction of the central portion in the width direction of the plate.
A circular arc portion 10C continuous to 0b is formed, and a circular arc portion 10C continuous to the circular arc portion 10C is formed on both sides of the circular arc portion 10C.
The wing portions 10d and 10e are formed on both sides with an opening angle of about 20° to 150°, and each wing portion 10d, 1
An insertion flange 10fjOg with a constant width plate surface protruding from the side edge of 0e is provided.

Further, the lower edge 10h of the partition member 10 is shaped to approximately match the outer shape of the valve head 14a, as shown in FIG.
It is formed so as to be partitioned right above the valve head 14a when the intake valve 14 is fully closed.

As shown in FIGS. 4a and 4b, the insertion flange 10 f jOg is provided with a slit groove 16 a provided in the axial direction of the cylindrical pin 16 and fitted with the pin 16 , 16 , respectively. A cylindrical insert 17 is formed by a cylindrical pin 16.16.

Corresponding to the insertion portion 17 of the partition member 10, a cylindrical fit is inserted from the combustion chamber side opening 6b side into the cylinder Rad inner wall defining the combustion chamber side opening 6b using a drilling tool such as a drill. Matching grooves 18, 18 are formed.

The partition member 10 is installed from the combustion chamber side opening 6b side so that the upper edge 10a of the partition member 10 is attached to the opposite end surface 9 of the partition wall 9.
Insert the insertion portions 17.17 of the partition member 10 into the fitting grooves 18, 18 from the axial direction until the fitting portions 10b of the partition member 10 come into contact with the protrusion 1 of the intake valve guide 15.
The intake hole 8 is fitted and fixed to the outer circumferential surface of the cylinder head 5a, and is further fitted into a ring-shaped fitting part 20 provided on the inner wall of the cylinder head.
By press-fitting the valve seat 21 forming the fitting groove 18
This is done by pressing and holding the insertion portion 17 of the partition member 10 inserted into j8 from the r direction.

As a result, the partition member 10 is pivotally supported by the intake valve guide 15, and together with the fixation of the insertion portion 17.17, the entire partition member 10 is almost completely fixed without wobbling.

Regarding the fitting part of the partition member, as shown in FIGS. 5a and 5b, a pair of gripping pieces 10i, 1 curved in a circular shape are inserted from the upper part of the arcuate part 10C of the partition member 10'.
0i, thereby forming a fitting portion 10b' that fits into the protrusion 15a of the intake valve guide 15.

Further, the structure of the insertion portion 17 of the partition member 10 is not limited to the above embodiment, and for example, the insertion flange 10f on both side edges 10d and 10e of the partition member 10.

10 g to be wider, and this is formed into the above-mentioned fitting groove 18.
．． Various structures can be adopted, such as forming it by rolling it into a cylindrical shape so that it can fit into the cylindrical shape.

In the above embodiment, the centroid of the cross-sectional area of the combustion chamber side part 6b of the low-load intake port 11 partitioned by the partition plate 10 is defined as G, and the centroid G and the valve shaft 14 b
When the straight line connecting the center P of is the mixture flow center line l, the intersection angle α between the mixture flow center line l and the tangent t passing through the intersection Q of this mixture flow center line l and the combustion chamber outer periphery 7a is 50 ~8
It is preferable to set it within the range of 0°.

If the intersection angle α between the air mixture flow center line l and the tangent line t is set in the above angle range, the low-load intake port 1-1
This is preferable for generating the mixture from 1 as a swirl.

That is, the air-fuel mixture supplied from the low-load intake passage 3 flows from the low-load intake port 11 when the intake valve 14 is opened.

The air-fuel mixture that is about to flow into the head 14a of the intake valve 14
Due to the streamlined shape on one side, the flow speed is increased and the direction is greatly changed, and the surrounding wall 7a of the combustion chamber generates a swirl S with large kinetic energy.

The air-fuel mixture generated as a powerful Swirl S promotes vaporization and atomization of the fuel, and is successfully ignited by a spark plug (not shown) facing the swirling area of the Swirl S.
After going through an explosion and expansion stroke, it is discharged to the outside from the exhaust hole 13.

As is clear from the above detailed explanation, the present invention partitions the intake passage in the cylinder head to just above the head of the intake valve using a partition wall and a partition member continuous with the partition wall, and forms a low-load intake port. In an engine intake system that is separated into a high-load intake port, the intake valve guide that slidably supports the shaft of the intake valve protrudes a certain amount from the opposite end face facing the combustion chamber side opening of the separation wall. The partition member is fixed by forming a protruding part, forming a fitting part that fits into the protruding part on the partition member, and fixing the fitting part to the protruding part. According to the present invention, the partition member can be securely fixed, and the partition member can be firmly supported without wobbling.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a main part of a cylinder head showing an embodiment of an engine intake system according to the present invention, and FIG.
3A and 3B are plan views and front views respectively showing an example of the partition member according to the present invention, and FIGS. 4A and 1] are plane views of the pins forming the insertion portion of the partition member. FIGS. 5A and 5B are a plan view and a front view showing another example of the partition member. 1...Intake manifold, 2...Cylinder head, 3.4...Intake pipe for low load and high load, 6...Inside the cylinder head intake passage,
6a... Atmospheric side opening, 6b... Combustion chamber side ['' part, 7... Combustion chamber, 9...
Separation wall, 10... Partition member, 10 b...
...Mating part, 14...Intake valve, 15...
- Intake valve guide, 15a... protrusion.

Claims (1)

[Claims for Utility Model Registration] Separate low-load and high-load intake pipes are provided, and they are cast at the same time as the cylinder head, and installed from the atmosphere-side opening of the intake passage in the cylinder head to the combustion chamber-side opening. a separation wall extending in an arc shape in the intake passage to a position a set distance away from the head of the intake valve; The intake passage is separated into a low-load intake port and a high-load intake port 1- by a partition member that extends continuously into the intake passage in an arc shape to just above the head of the intake valve. In the engine intake system formed by connecting the low-load and high-load intake pipes, the intake valve has a protrusion that protrudes into the intake passage from the opposing end surface toward the combustion chamber side opening. An intake valve guide having an inner circumferential surface that slidably supports the shaft portion is provided, and a fitting portion is provided on the partition member to be fitted to the outer circumferential surface of the protruding portion of the intake valve guide. Engine intake system.