JP2594971Y2 - Engine intake system - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake device for an engine capable of generating a strong tumble flow in a cylinder during an intake stroke of the engine.

[0002]

2. Description of the Related Art In an engine operating region, in a low load region in which the throttle opening is small and the intake air amount is correspondingly small, the mixture is generally set to be rich so as to stabilize combustion. Emissions tend to deteriorate. Therefore, as a measure for improving the fuel efficiency and the emission, a technique of generating a tumble flow in an intake air-fuel mixture in a cylinder is conventionally generally known. The generation of this tumble flow causes the intake air-fuel mixture to swirl along the axial direction of the cylinder. In the latter half of the compression stroke, the tumble flow collapses, generating strong turbulence and igniting the turbulent air-fuel mixture. By doing so, a turbulent combustion can be obtained in which the combustion speed is high and the combustion is stable, so that it is particularly effective for improving the combustion in a low to medium load region of the engine.

[0003] Such a tumble flow can be generated by sucking the intake air passing through the intake port into the cylinder as a deflected flow that is shifted toward the center of the combustion chamber. In view of the above, various types of intake devices have been proposed which generate a deflected flow for generating a tumble flow in an intake port (Japanese Utility Model Application Laid-Open No. 59-156122 and Japanese Utility Model Application Laid-Open No. 63-48).
No. 920).

The intake system described in Japanese Utility Model Laid-Open Publication No. 59-156122 divides the vicinity of an intake port into a main intake passage and a sub intake passage, and the main intake passage has a low engine load region. A closed on-off valve is installed, and in the low load region of the engine where the on-off valve is closed, a tumble flow is generated by sucking the air-fuel mixture into the cylinder as a deflected flow only from the auxiliary intake passage. is there. Also,
In the intake device described in Japanese Utility Model Laid-Open Publication No. 63-48920, a rectifying section integrally formed on a valve head of an intake valve causes intake air passing through the intake port to flow into the cylinder while being deflected toward the center of the combustion chamber. It is like that.

[0005]

The intake device described in Japanese Utility Model Laid-Open Publication No. 59-156122 is a partition that partitions the vicinity of an intake port into a main intake passage and a sub intake passage, and opens and closes the main intake passage. The structure requires a valve, and the structure is relatively complicated. In addition, the aforementioned Japanese Utility Model Laid-Open No. 63-489
In the intake device described in Japanese Patent Publication No. 20, the rectifying portion for diverting the intake air flow in the intake port toward the center of the combustion chamber is formed integrally with the intake valve, and the intake valve rotates around the axis of the valve stem. Therefore, there is a problem that uneven wear occurs on the contact surface between the valve head and the valve seat to impair the function of the intake valve.

Accordingly, the present invention provides an intake system for an engine which has a relatively simple structure and which can generate a strong tumble flow in a cylinder during the intake stroke of the engine while sufficiently maintaining the function of the intake valve. It is intended to provide a device.

[0007]

SUMMARY OF THE INVENTION For this purpose, the present invention provides a deflector plate capable of generating a tumble flow in a cylinder by deflected an intake flow passing through an intake port of an engine toward a central portion of a combustion chamber. The drift plate is provided so as to be relatively rotatably mounted on a valve stem portion of an intake valve facing the intake port while being prevented from rotating by engagement with a guide rib formed on the inner wall of the intake port. .

[0008]

In the intake device for an engine according to the present invention employing such means, the intake air passing through the intake port during the intake stroke of the engine is mounted on the valve stem portion of the intake valve facing the intake port. It is drawn into the cylinder while being guided by the drift plate and drifting toward the center of the combustion chamber, so that a strong tumble flow is generated in the cylinder.

The drift plate is engaged with a guide rib in the intake port and is prevented from rotating, and is mounted so as to be rotatable relative to a valve stem portion of the intake valve. It rotates around the axis of the valve stem according to the operation, and uneven wear of the contact surface between the valve head and the valve seat is prevented.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be specifically described below with reference to the accompanying drawings. In FIG. 1 showing an overall schematic configuration of an engine intake device according to an embodiment, reference numeral 1 denotes an engine body in which a cylinder head 3 is connected to a cylinder block 2, and a piston 5 slides in a cylinder 4 of the cylinder block 2. It is movably fitted.

The cylinder head 3 has an intake port 8 communicating with a combustion chamber 7 via an intake valve 6 and an exhaust port 10 communicating with the combustion chamber 7 via an exhaust valve 9.
Are formed. And in this cylinder head 3,
An end of the intake manifold 11 that distributes the air-fuel mixture is continuously connected to the intake port 8. In addition, an ignition plug 12 is provided at the center of the combustion chamber 7.

Here, a deflector plate 13 is mounted on the valve stem portion 6a of the intake valve 6 facing the intake port 8, for causing the mixture flow passing through the intake port 8 to be deflected toward the center of the combustion chamber 7. Have been.

FIG. 2 shows the appearance of the drift plate 13, which has a cylindrical portion 13b having a fitting hole 13a which bulges out to the center with its axis inclined.
A guide groove 13d is formed in the periphery of the brim-shaped main body 13c, which is continuous with b, at the inclined side of the cylindrical portion 13b. As shown in FIG. 3, such a drift plate 13 covers the large-diameter shaft portion 6c that connects the valve stem portion 6a of the intake valve 6 and the valve head 6b. It is loosely fitted to the portion 6a so as to be relatively rotatable, and is held between a stop ring 15 such as a C-shaped ring mounted together with the wave washer 14 on the valve stem portion 6a and the step 6d on the large-diameter shaft portion 6c side. ing.

On the other hand, as shown in FIG. 1, a guide rib 8b is slidably engaged with a guide groove 13d of the drift plate 13 on a bent inner wall surface 8a of the intake port 8. The guide rib 8b has a guide groove 13d.
The deflector plate 13 with which the main body 13c is obliquely inclined so that the mixed gas flow passing through the intake port 8 is deflected toward the center of the combustion chamber 7, is prevented from rotating. It can be moved up and down together with the stem portion 6a.

Next, the operation of the thus-configured intake device for an engine according to this embodiment will be described. In this embodiment, during the intake stroke of the engine with the intake valve 6 opened, the intake air-fuel mixture flowing into the intake port 8 from the intake manifold 11 flows along the main body 13c of the drift plate 13 toward the center of the combustion chamber 7 To drift to The deflected flow of the intake air-fuel mixture is sucked into the cylinder 4 from the center of the combustion chamber 7 along the cylinder wall on the exhaust valve 9 side as shown by an arrow in FIG. , A tumble flow of the intake air-fuel mixture is generated in the cylinder 4.

The tumble flow of the intake air-fuel mixture generated in the cylinder 4 collapses and becomes turbulent in the latter half of the compression stroke of the engine, so that stable and rapid turbulent combustion is performed. As a result, the fuel efficiency is greatly improved, and the exhaust emission is improved.

Here, the drift plate 13 is engaged with the guide rib 8b in the intake port 8 and is prevented from rotating, and is attached to the valve stem portion 6a of the intake valve 6 so as to be relatively rotatable. The intake valve 6 can rotate around the axis of the valve stem portion 6a according to the opening / closing operation. Therefore, uneven wear of the contact surface between the valve head 6b of the intake valve 6 and the valve seat 16 is prevented beforehand, and the function of the intake valve 6 is sufficiently maintained.

Here, a structural view of the present embodiment shows that the guide ribs 8 formed on the inner wall surface 8a of the intake port 8 are bent.
b, the valve stem portion 6 of the intake valve 6 facing the drift plate 13 into the intake port 8 in a state of being prevented from rotating by engagement with
a, it is only necessary to mount the main intake passage to the main intake passage and the auxiliary intake passage in the vicinity of the intake port 8, and the structure requires a valve for opening and closing the main intake passage. Is relatively simple.

[0019]

As described above, according to the present invention, during the intake stroke of the engine, the intake air passing through the intake port is guided to the drift plate mounted on the valve stem of the intake valve and facing the intake port. Then, it is sucked into the cylinder while drifting toward the center of the combustion chamber. Therefore, a strong tumble flow can be generated in the cylinder during the intake stroke of the engine.

Here, the deflector plate is engaged with a guide rib in the intake port and is prevented from rotating, and is mounted so as to be rotatable relative to the valve stem portion of the intake valve. Rotates around the axis of the valve stem. Therefore, uneven wear of the contact surface between the valve head and the valve seat of the intake valve is prevented, and the function of the intake valve can be sufficiently maintained.

From a structural point of view, the present invention mainly comprises a drift plate that is relatively rotatably mounted on the valve stem portion of the intake valve while being prevented from rotating by the guide rib of the intake port. Therefore, the structure is relatively simple as compared with a conventional example in which a partition partitioning the vicinity of the intake port into a main intake passage and a sub intake passage and an opening / closing valve for the main intake passage are required.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an overall schematic configuration and operation of an embodiment of an engine intake device according to the present invention.

FIG. 2 is an external perspective view of a drift plate in one embodiment.

FIG. 3 is a cross-sectional view showing a structure for mounting a drift plate in one embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine main body 2 Cylinder block 3 Cylinder head 4 Cylinder 5 Piston 6 Intake valve 6a Valve stem part 6b Valve head 6c Large diameter shaft part 6d Step part 7 Combustion chamber 8 Intake port 8a Curved inner wall surface 8b Guide rib 9 Exhaust valve 10 Exhaust port DESCRIPTION OF SYMBOLS 11 Intake manifold 12 Spark plug 13 Drift plate 13a Fitting hole 13b Tubular part 13c Main body 13d Guide groove 14 Wave washer 15 Stop ring 16 Valve seat

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) F02B 31/00 F01L 3/06

Claims (1)

(57) [Scope of request for utility model registration] An airflow passing through an intake port of an engine is deflected toward a center portion of a combustion chamber to generate a tumble flow in a cylinder. An intake device for an engine, wherein the intake device is rotatably mounted on a valve stem portion of an intake valve facing an intake port while being prevented from rotating by engagement with a guide rib formed in the intake valve.