JPS5856331Y2 - Internal combustion engine with dual intake device - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to an internal combustion engine with a dual intake system.

Generally, in order to improve the exhaust performance (HC, CO, NOx) of internal combustion engines and improve fuel efficiency, it is necessary to generate moderate gas flow turbulence in the combustion chamber during idling and low-load operation. This is effective when the fuel ratio is leaner or when operating with exhaust gas recirculation.

Conventionally, this has been done by bending the suction boat or using a shrouded valve to create turbulence within the combustion chamber, but this has had the disadvantage of increasing suction resistance in high-load operating ranges and making it difficult to increase output.

To solve this problem, idle with a small amount of intake air,
In low-load operating ranges, intake air is introduced only from the primary boat at an increased flow rate, and in high-load operating ranges where the amount of intake air increases, intake air is supplied separately to the combustion chamber from both the primary boat and secondary boat. So-called dual inhalation devices are being considered.

This dual intake device has a primary boat and a secondary boat.
It is important to create a gas seal between the boat and the combustion chamber side using one intake valve, and also to seal the primary boat and the secondary boat when the intake valve is closed.
It was difficult to perform both seals at the same time when the intake valve was closed.

For example, as in Japanese Patent Publication No. 51-19094, the gas seal with the combustion chamber is performed at the normal valve seat, and the seal when the intake valves of the primary boat and the secondary boat are closed is at the combustion chamber opening of the secondary boat. In the case where a cylinder or tube is press-fitted to the intake valve and the end of the cylinder or tube contacts the back side of the intake valve to form a seal, if the normal valve seat part becomes worn, the end of the cylinder or tube at the intake valve It is supposed to secure a suitable seal by hitting the
The disadvantage is that depending on the degree of press fit, it is possible for the cylinder or tube to fall out or not move when struck by the intake valve.

In other words, the seal disclosed in Japanese Patent Publication No. 51-19094 attempts to compensate for the amount of wear by striking the tube end with the umbrella portion of the suction valve and moving the tube, which is separate from the cylinder head material. .

Therefore, the tube must be installed so that it can slide against the cylinder head material, but if it is held too tightly, it will collide with the intake valve, not only will it not be possible to seal it, but it will also damage the tube and intake valve. If it is too loose, it will retract too much when it comes into contact with the intake valve as it rises, and not only will it not function as a partition between both intake passages, but it will also fall off.

Therefore, in practice, the degree of retention must be adjusted very strictly to be of any use, and simply fitting a separate tube to the cylinder head material is of no practical use.

Since they are separate bodies, their coefficients of thermal expansion differ, and the degree of retention changes depending on the temperature.

Furthermore, when installing the tube, the accuracy of its axial position is also required.
If even the slightest deviation occurs, the contact between the tube end and the valve head becomes uneven, creating a gap and deteriorating the sealing performance.

Furthermore, the cost of the tube itself, the processing of the tube, the processing of the cylinder head material for mounting the tube, etc., inevitably become extremely expensive.

In view of the above-mentioned drawbacks of the conventional art, the present invention solves the problem that the seal between the primary port and the secondary port when the suction valve is closed may fall off depending on the degree of press-fitting of the cylinder or tube, or the suction valve may To obtain an internal combustion engine having a dual suction device which can be reliably opened and closed by solving the problem of not moving even when struck.

Hereinafter, the present invention will be explained in detail with reference to embodiments shown in the drawings.

In the embodiment of FIGS. 1 and 2, 1 is the cylinder 2
This is a cylinder block formed with

Reference numeral 3 denotes a cylinder head made of, for example, aluminum alloy casting, which is tightened and fixed to the cylinder block 1 via a gasket or the like.

4 is a piston that reciprocates within the cylinder 2.

Reference numeral 5 denotes a combustion chamber formed by the cylinder 2 and a recess formed in the cylinder head 3.

Reference numeral 6 denotes a dual-type inhaler, and the multiple-type inhaler 6 includes a double-barrel carburetor 7, a primary manifold 8 communicating with a primary side 7a of the carburetor 7, and a secondary side 7 of the carburetor 7.
The secondary manifold 9 is connected to the primary pot 11 and the secondary manifold 9 is connected to the primary manifold 8, and the secondary manifold 9 is connected to the primary pot 11, which is connected to the primary manifold 8.
A secondary port 12 communicates with the primary port 11, and a valve seat 13 made of ordinary heat-resistant steel inserted into the combustion chamber 5 side end of the primary port 11. It is composed of an intake valve 14 whose umbrella part can seal between the primary port 11 and the secondary port 12,
The inclination angle θ (usually about 45°) between the seal portion 15, which is the seating surface of the valve seat 13, and the seat portion 16, which is the seating surface of the umbrella portion of the suction valve 14 at the end of the partition wall 10, is the same. It is formed.

Therefore, processing in this case is carried out by simultaneously cutting the sheet 13 and the partition wall 10 with a cutter having an angle of θ after press-fitting the sheet 13.

Next, a different embodiment of the present invention shown in FIG. 3 will be explained.

In the description of this embodiment, the same parts as in the previous embodiment are denoted by the same reference numerals, and redundant explanation will be omitted.

The embodiment shown in FIG. 3 is mainly different from the previous embodiment in the inclination angle θ2 of the seal portion 15, which is the seating surface of the valve seat 13, and the seating of the umbrella portion of the suction valve 14 at the end of the partition wall 10. With this configuration, the weight of the intake valve can be made equal to that of a normal internal combustion engine in that the inclination angle θ1 of the seal portion 16, which is a surface, is different.

Further, since the processing can be performed integrally using a stepped taper cutter with an angle of 01 on the inside and θ2 on the outside, the number of processing steps is the same as in the previous embodiment.

In the dual intake system, the intake passage from the carburetor 7 to the opening of the combustion chamber 5 has a primary IJ-7a and a secondary IJ-7A.
7b is formed separately.

Therefore, in low speed and low load ranges with a small amount of intake air, the throttle valve on the primary 7a side is opened, and the air-fuel mixture is supplied to the combustion chamber 5 only via the primary manifold 8 and primary port 11. .

Therefore, the passage area is only on the primary side and is small, so the flow rate of intake air increases and the primary port 11
Coupled with the shape of the combustion chamber 5, a swirl is generated in the combustion chamber 5, and the air-fuel mixture is sucked in, thereby improving combustibility.

Furthermore, at high speeds and high load ranges where the amount of intake air increases, the throttle valve on the secondary l/-7b side of the carburetor 7 also opens, so the air-fuel mixture is sucked in from both the primary 7a and secondary 7b. Therefore, intake resistance is reduced and intake efficiency is improved.

By the way, when the primary port 11 and the secondary port 12 in such a dual suction device 6 are defined by the partition wall 10 integrally formed from the material of the cylinder head 3 as described above, this partition wall 10 becomes Since it is softer than the valve seat 13 (usually made of aluminum, etc.), the intake valve 14 may be damaged depending on the wear of the valve seat 13.
The partition wall 10 that comes into contact with the back side of the umbrella part is worn out, and the seal part 16 can always maintain good sealing performance between the primary port 11 and the secondary port 12.

That is, in the present invention, since the partition wall is formed of a cylinder head material that is softer than the valve seat, the partition wall will wear out as the valve seat wears, and the suction valve will come into contact with the partition wall, so the valve seat of the intake valve and The contact between the partition wall and the intake valve is not obstructed, and conversely, there is no gap between the partition wall and the intake valve due to excessive wear or upheaval of the partition wall.

Furthermore, processing accuracy and fitting accuracy are not required so much, and sealing performance is automatically ensured.

Furthermore, since the partition wall of the present invention is integrally molded with the cylinder head material, there is no need for moving parts, there is no need to worry about it retracting too much or falling off, and the coefficient of thermal expansion is the same, so it is not affected by temperature changes. Not at all.

Since the partition wall wears out as it comes into contact with the intake valve head, concentricity is not very necessary, and since the cylinder head is molded, especially integrally, the cost does not increase.

As is clear from the above description, the present invention has the following effects.

(1) Since the partition wall defining the primary port and the secondary port is integrally molded with the cylinder head, the primary port and the secondary port can be easily formed.

(2) The processing of each seal portion is simple and easy, and the number of processing steps can be far similar to that of a normal internal combustion engine.

(3) The primary port and the secondary port can be reliably sealed when the suction valve is closed even if the valve seat is worn.

That is, since the sealing surfaces between the primary port and the secondary port are made of a softer material than the valve seat, they tend to wear out following the wear of the valve seat.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram showing one embodiment of the present invention, FIG. 2 is an enlarged view of the main part of the present invention, and FIG. 3 is an explanatory diagram of the main part showing a different embodiment of the present invention. 1...Cylinder block, 2...Cylinder, 3...Cylinder head, 4...
Piston, 5... Combustion chamber, 6... Dual suction device, 7... Multi-barrel carburetor, 8...
Primary manifold, 9...Secondary
Manifold, 10... Partition wall, 11...
・Primary port, 12...Secondary
Port, 13... Valve seat, 14...
...Intake valve, 15... Seal part, 16...
...Seal part.

Claims (3)

[Scope of utility model registration request] (1) An internal combustion engine having a dual intake device in which the primary side intake passage and the secondary side intake passage of the double-barrel carburetor are separated from each other until they open into the combustion chamber through one common intake valve. In this, the cylinder head is made of a material softer than the intake valve seat, a partition wall that separates the primary boat and the secondary boat is integrally molded with the cylinder head material, and the primary boat and the combustion chamber are formed integrally with each other. The sealing between the primary boat and the secondary boat is performed by the valve seat provided at the combustion chamber side end of the primary boat and the cap portion of the suction valve, and the sealing between the primary boat and the secondary boat is performed by the end of the partition wall and the cap portion of the suction valve. An internal combustion engine having a dual suction device characterized in that the suction is carried out by contact between the two suction devices. (2) An internal combustion engine having a dual intake device according to claim 1, wherein the valve seat, the partition wall, and the valve head portion are in contact with each other at the same angle. (3) An internal combustion engine having a dual intake device according to claim 1, wherein the valve seat, the partition wall, and the valve cap are brought into contact with each other at different angles.