JP4151412B2 - Intake device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an intake device for an internal combustion engine in which an intake port in a cylinder head is partitioned into upper and lower divided intake ports by a partition plate.
[0002]
[Prior art]
Patent Document 1 discloses an intake passage structure in which an intake port in a cylinder head is partitioned into upper and lower divided intake ports by a partition plate in order to enhance the tumble flow (vertical vortex flow) of intake air introduced into a cylinder of an internal combustion engine. It is known.
[0003]
Moreover, in patent document 1, when casting a partition plate at the time of casting of a cylinder head, a partition plate is made into the corrugated plate shape as a countermeasure of a partition plate deformation | transformation by thermal expansion.
[0004]
[Patent Document 1]
JP 2001-193469 A (particularly paragraph numbers 0020 and 0022)
[0005]
[Problems to be solved by the invention]
However, the corrugated plate-like partition plate as in Patent Document 1 can absorb the thermal expansion in the radial direction of the intake port, but the thermal expansion in the axial direction of the intake port, which is the longitudinal direction of the partition plate, Despite its large thermal expansion, it cannot absorb.
[0006]
For this reason, when the partition plate is set and cast into the core for forming the intake port during casting of the cylinder head, the longitudinal end portion of the partition plate is caused by a difference in thermal expansion between the partition plate and the core (cast sand). Will cause cracks in the core, and hot water (aluminum) will flow into the cracked part and generate burrs. There was a problem that the deburring work was extremely troublesome.
[0007]
SUMMARY OF THE INVENTION The present invention has been made in view of the above-described conventional problems, and it is an object of the present invention to avoid cracking of a core due to thermal expansion in the longitudinal direction of a partition plate when casting the partition plate during casting of a cylinder head. To do.
[0008]
[Means for Solving the Problems]
For this reason, in this invention, it is set as the structure which divides | segments into a some in the intake port axial direction the partition plate cast in a cylinder head, and forms a clearance gap between division parts.
[0009]
【The invention's effect】
According to the present invention, by dividing the partition plate to be cast into the cylinder head in the longitudinal direction, the respective thermal expansion can be reduced and the thermal expansion can be absorbed in the gaps between the divided portions. The core can be prevented from cracking.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
1 is a cross-sectional view of a cylinder head of an internal combustion engine showing an embodiment of the present invention, FIG. 2 is a plan view of an intake port along line AA in FIG. 1, and FIG. 3 is a cylinder as viewed in the direction of arrow B in FIG. FIG. 4 is an enlarged cross-sectional view of the intake port.
[0011]
The cylinder head 1 cast from an aluminum alloy is provided with two intake ports 3 and two exhaust ports 4 for the cylinder 2.
The two intake ports 3 open into the cylinder 2 via the intake valves 5 (FIG. 4) on the downstream side, and open to the side wall (intake port opening surface) 6 of the cylinder head 1 on the upstream side.
[0012]
The intake port 3 includes partition plates 7 and 8 made of aluminum alloy (for example, duralumin having higher strength than a general aluminum alloy for cylinder head casting), SUS, or the like that partitions the intake port 3 into upper and lower divided intake ports 3a and 3b. Is provided. Here, the partition plates 7 and 8 partition the two intake ports 3 up and down together, but are divided into two in the longitudinal direction (intake port axial direction) and between the divided portions (upstream partition plates). 7 and a downstream partition plate 8), a thermal expansion absorbing gap C is formed.
[0013]
Although not shown, the partition plate 7 on the side of the intake port 3 is substantially extended into the branch portion of the intake manifold 3 made of resin, for example, connected to the intake port 3 of the cylinder head 1. The interior of the branch is also divided vertically. The lower divided passage among the divided passages in the branch portion is provided with a tumble control valve for opening and closing the divided passage, and only the upper divided intake port 3a is closed by closing the tumble control valve under a predetermined operating condition. The intake air can be introduced into the cylinder 2 through this, thereby enhancing the tumble flow of the intake air and improving the fuel consumption.
[0014]
The partition plates 7 and 8 are cast into the cylinder head 1 when the cylinder head 1 is cast.
Specifically, as shown in FIGS. 5 and 6, the partition plates 7 and 8 are set on the core 10 for forming the intake port at the time of casting the cylinder head, and a part of the partition plates 7 and 8 is placed in the middle. It protrudes from the side of the child 10 and is cast into the inner wall of the intake port of the cylinder head 1 at that portion. In this example, the cores for two cylinders (four) are integrated by a support baseboard (casting sand) 11.
[0015]
By adopting a structure in which the partition plates 7 and 8 are fixed to the cylinder head 1 by casting as described above, the partition plates 7 and 8 can be made sufficiently thin to suppress the airflow resistance, and the partition plate 7 and 8 can be formed of a suitable material such as duralumin or SUS different from the cylinder head 1.
[0016]
7 and 8, when the cylinder head 1 is cast, even if the partition plates 7 and 8 are thermally expanded in the longitudinal direction, they are divided in advance, so that each thermal expansion is reduced, and Since thermal expansion can be absorbed in the gaps C between the divided portions, it is possible to avoid cracks in the core 10 starting from the end portions of the partition plates 7 and 8.
[0017]
Next, a further improved embodiment will be described with reference to FIGS.
In the case of FIG. 4, the main flow (MF in the figure) of the intake air flowing through the upper divided intake port 3a is slightly separated from the gap C between the divided portions of the partition plates 7 and 8, but as shown in the dotted line in the lower part. There is a risk of leakage into the intake port 3b, leading to a decrease in engine performance.
[0018]
Therefore, in the embodiment of FIG. 9, the divided surfaces 7 a and 8 a facing each other in the divided portions of the partition plates 7 and 8 are inclined with respect to a plane perpendicular to the plate surface of the partition plates 7 and 8, and the divided surfaces 7 a and 8 a The upper part is located downstream in the intake flow direction, and the lower part is located upstream in the intake flow direction.
[0019]
As described above, the upper (main flow side) division position of the partition plates 7 and 8 is arranged downstream of the lower division position in the intake flow direction, thereby reducing intake main flow leakage and ensuring engine performance. be able to.
[0020]
Further, in the embodiment of FIG. 10, out of the split end portions facing each other in the split portions of the partition plates 7 and 8, the split end portion of the upstream partition plate 7 protrudes downstream from its upper portion. An eaves 9 is provided, and the upper surface of the divided end portion of the partition plate 8 on the downstream side is covered with the flange 9. Further, the downstream partition plate 8 is made thinner than the upstream partition plate 7. In other words, the divided end portion of the upstream partition plate 7 has an L-shaped cross section so as to cover the upper surface of the downstream partition plate 8 having a reduced plate thickness.
[0021]
By doing so, leakage of the mainstream of intake air can be reduced and engine performance can be ensured. Moreover, since the plate | board thickness of the downstream partition plate 8 can be made thin, the amount of thermal expansion can be reduced, and since the clearance gap C can be made small by that much, the leakage of the mainstream of intake air can be reduced more.
[0022]
Further, in the embodiment of FIG. 11, among the divided end portions facing each other in the divided portions of the partition plates 7 and 8, the divided end portion of the upstream partition plate 7 is further downstream than the upper portion and the lower portion thereof. The eaves 9a and 9b are provided so as to cover the upper and lower surfaces of the divided end portion of the downstream partition plate 8 by these eaves 9a and 9b. In other words, the divided end portion of the upstream partition plate 7 has a U-shaped cross section, and the divided end portion of the downstream partition plate 8 having a reduced thickness is inserted into the recessed portion.
[0023]
According to the embodiment of FIG. 11, the same effect as that of the embodiment of FIG. 10 can be obtained, and the shape of the joint of the dividing portion becomes more complicated, so that the leakage of the mainstream of intake air can be further reduced.
[0024]
In the above embodiment, the description has been given of the case where the two intake ports provided for each cylinder are independent. However, the Siamese type of branching into two at the downstream side and collecting into one at the upstream side. Needless to say, it can also be applied.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a cylinder head of an internal combustion engine showing an embodiment of the present invention. FIG. 2 is a plan view of an intake port along line AA in FIG. Drawing of the intake port opening surface of the cylinder head [Fig. 4] Expanded sectional view of the intake port [Fig. 5] Plan view of the core for forming the intake port [Fig. 6] Front view of the core for forming the intake port [Fig. ] Explanatory drawing of thermal expansion during casting [FIG. 8] Enlarged view of part X in FIG. 7 [FIG. 9] Diagram showing an improvement example (1) of the split part [FIG. 10] An improvement example (2) of the split part FIG. 11 is a diagram showing an improvement example (3) of the dividing unit.
DESCRIPTION OF SYMBOLS 1 Cylinder head 2 Cylinder 3 Intake port 3a Upper division | segmentation intake port 3b Lower division | segmentation intake port 4 Exhaust port 5 Intake valve 6 Cylinder head intake port opening surface 7, 8 Partition plate C Dividing part gap 7a, 8a Inclined division Surface 9, 9a, 9b eaves
10 Inlet port forming core 11 Skirting board

Claims (4)

In the intake system for an internal combustion engine in which a partition plate that partitions the intake port into upper and lower divided intake ports is cast into the cylinder head.
An intake device for an internal combustion engine, wherein a partition plate to be cast into the cylinder head is divided into a plurality of portions in the intake port axial direction, and a gap is formed between the divided portions. In the split part of the partition plate, the split surfaces facing each other are inclined with respect to a plane perpendicular to the plate surface of the partition plate, the upper part of the split surface is located downstream in the intake flow direction, and the lower part is the intake flow 2. The intake device for an internal combustion engine according to claim 1, wherein the intake device is located upstream in the direction. Among the split end portions facing each other in the split portion of the partition plate, the upstream split end portion protrudes downstream from the upper portion thereof, and a ridge that covers the upper surface of the downstream split end portion is formed. 2. An intake device for an internal combustion engine according to claim 1, wherein the intake device is an internal combustion engine. Of the divided end portions facing each other in the divided portion of the partition plate, the upstream divided end portion protrudes downstream from the upper portion and the lower portion, respectively, and the upper surface and the lower surface of the downstream divided end portion are formed. 2. The intake device for an internal combustion engine according to claim 1, wherein a cover is formed.

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