JPS5810566B2 - Method for manufacturing intake ports for internal combustion engines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates primarily to improvements in dual intake port structures for internal combustion engines for automobiles.

In order to improve combustion in internal combustion engines, especially in the low load range, it is possible to add swirl to the intake air mixture to promote fuel atomization, induce swirling motion in flame propagation, and shorten combustion time. well known.

For this purpose, a swirl generating means is attached to the intake port,
When swirling motion is imparted to the air-fuel mixture, the increase in intake resistance caused by this swirl generating means causes a new problem that cannot be ignored from the perspective of engine output performance, especially when high output is required such as in high-speed, high-load ranges. caused it to happen.

In other words, although the swirl is extremely effective in the low load range, in the high load range where combustion conditions are favorable, it actually causes noise increase due to excessive combustion, and also causes a reduction in charging efficiency due to increased intake resistance, resulting in a full-throttle output characteristic. This resulted in results that were contrary to essential requirements, such as not being able to sufficiently increase

Therefore, as proposed in Japanese Patent Application No. 51-33015 (Japanese Unexamined Patent Publication No. 52-115917) by the present applicant, the interior of the intake port is divided into two stages, and the lower low port is used as the primary passage of the carburetor. By connecting the upper high port to the secondary passage, the air-fuel mixture is guided and supplied only from the low port in the low to medium load range to produce a strong swirl, and in the high load range there is little intake resistance. An engine has been proposed in which a large amount of air-fuel mixture is supplied also from a high port to cancel out the swirl while maintaining a predetermined charging efficiency, thereby satisfying the requirements in the entire operating range of the engine.

By the way, conventional methods for processing this intake port include splitting the sand core into two and integrally casting a two-stage port when casting the cylinder head, or forming only one of the ports during casting. , and the rest was manufactured by machining (for example, drilling).

However, the former has a major problem in producing the core during casting.
In order to obtain the desired shape, core manufacturing is difficult and large, making it impractical.According to the latter, it is almost impossible to process a port with a complex shape, and the required performance cannot be obtained with a simple port. There were drawbacks.

The present invention was proposed in order to solve this problem, and a part for holding the intake port core is provided on the partition plate that divides the low port and the high port, and this partition plate is embedded in the port core to hold it. This integrated intake port core is cast into the intake port part during cylinder head casting to manufacture a two-stage intake port, and the port shape that meets the required characteristics can be created with good productivity. The aim is to realize the following.

Hereinafter, a specific example for carrying out the method of the present invention will be described. In FIG. 1, 1 is an intake port, 2 is an exhaust port, 3 is an intake valve, 4 is an exhaust valve, 5 is a cylinder, and 6 is a Pistons 7a and 7b indicate two spark plugs facing the combustion chamber 8.

This example is based on two-point ignition and high-rate exhaust gas recirculation, making it possible to extremely reduce the generation of NOx.
This is an example for an ignition engine.

Therefore, the partition plate 12 is configured to divide the inside of the intake port 1 into a high port 10 and a low port 11 on a substantially horizontal plane.
will be placed.

The high port 10 is connected to the secondary side of a carburetor (not shown), and the low port 11 is also connected to the primary side. Therefore, the low port 11 is always supplied with air-fuel mixture, but the high port 10 is connected to the secondary side. As the valves begin to open, air-fuel mixture is supplied for the first time in the high load range.

The partition plate 12 is formed by sheet metal working and press working as shown in FIG. , is provided with a curved guide portion 14 oriented in the tangential direction so as to generate a swirling flow in the circumferential direction within the cylinder and to reduce the inflow resistance of the air-fuel mixture flowing into the high port 10.

This guide portion 14 is formed by bending the end surface of the partition plate 12 on the connection side of the combustion chamber along the valve shaft 3a, so that the air-fuel mixture from the low port is not obstructed by the valve shaft 3a and enters the combustion chamber. It is now flowing into the country.

The partition plate 12 is cast integrally with the intake port core during cylinder head casting, and at this time, it improves the ease of attachment to the cylinder head body and the adhesion (integration) with the core. Therefore, the mounting portion 16a as shown in FIGS. 2 to 5.

16b, 16c and 16d.

The mounting portion 16a shown in FIG. 2 is provided with a plurality of protrusions in the shape of a so-called lug in order to improve the mountability with the cylinder head main body, and at the same time, the cores on both sides separated by the partition plate 12 are integrally mounted. A through hole 17 for bonding is also provided to improve adhesion to the core.

In the case of Fig. 3, the core has ring attachment parts 16b on both ends of the core to hold the core in a headband shape, and is fixed to the partition plate 12 by welding or the like, which improves the ease of mounting to the cylinder head and the inner diameter. At the same time, it has good adhesion to children.

Further, FIG. 4 shows a ring-shaped attachment part 16c that is almost the same as that in FIG. Therefore, compared to FIG. 3, the manufacturing process can be simplified.

The mounting portion 16a shown in FIG. 5 is formed in a cylindrical shape so as to completely surround the partition plate 12 in the port axial direction, and has the advantage that the core can be manufactured most easily.

In this way, the partition plate 12, which is integrated with the core, is integrally cast when the intake port 1 is cast, and the low port 11 and the high port 10 are partitioned, so that they can be formed into the desired shape. , high swirl performance at the low port 11 and reduction in intake resistance at the high port 10 are sufficiently achieved.

Furthermore, since the partition plate 12 is cast, the dual port is easy to manufacture and the productivity is very high.

In addition, the core molding during casting also has a simpler shape and is easier to manufacture than a single core.

[Brief explanation of drawings]

FIG. 1 is an overall perspective view of the present invention, and FIGS. 2 to 5 are perspective views showing respective embodiments of the partition plate. 1... Intake port, 2... Exhaust port, 3... Intake valve, 4... Exhaust valve, 5... Cylinder, 6... Piston, 10... High port, 11...・Low port, 1
2... Partition plate, 13... Notch part, 14... Curved guide part, 16a. 16b, 16c, 16a... Attachment parts.

Claims (1)

[Claims] 1 The intake port that communicates with the combustion chamber is divided into two stages,
In an internal combustion engine that has a low port for generating swirl and a high port for high output, a partition plate that divides the low port and high port is provided with a part that holds an intake port core, and this partition plate is embedded in the Manufacture of an intake port for an internal combustion engine, characterized in that an integrated intake port core is formed by the holding part, and this intake port core is cast into the intake port part during cylinder head casting to manufacture a two-stage divided intake port. Method.