JPS6117247Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to an exhaust gas recirculation passage installed in an internal combustion engine for exhaust gas purification, and in particular, the invention relates to an exhaust gas recirculation passage installed in an internal combustion engine as a measure for exhaust gas purification. This relates to improvements to the format built into the main body.

[Conventional technology]

In this type of exhaust gas recirculation passage, an exhaust gas recirculation passage with an EGR valve is connected from the exhaust gas inflow port on the exhaust side to the outflow port on the suction side, and a part of the exhaust gas is returned to the suction side. It is beginning to purify. By the way, it is known that the passage in this case is not constructed from a pipe disposed outside the engine body, but is built inside the cylinder head.

However, with the conventional ones, for example,
As shown in Publication No. 143128 and Japanese Utility Model Application Publication No. 53-12919, holes are formed in the inlet port and the cylinder head to communicate with the exhaust port, and suction is carried out from this inlet port through the cylinder head and the inside of the suction pipe. An exhaust gas recirculation passage is formed on the side by the same mechanical hole machining, and an outflow port is further formed in the intake pipe by hole machining so as to communicate with the intake passage. and,
In order to prevent leakage of exhaust gas, a hole for press-fitting a blind plug is machined into the unnecessary open end of each port, and then a blind plug is press-fitted.

[Problem that the invention attempts to solve]

As mentioned above, the conventional method involves drilling holes for press-fitting the blind plug and press-fitting the blind plug into the hole, which causes problems such as the machining and work is troublesome and the structure becomes complicated. Ta.

The present invention aims to eliminate such problems.

[Means for solving problems]

In order to achieve the above object, the present invention is a cylinder head having an exhaust port and an intake port facing each other, and an exhaust pipe and an intake pipe connected to these ports, respectively. A first exhaust gas recirculation passage is formed by an exhaust gas inflow port provided at the joint between the cylinder head and the intake pipe, and a passage provided through the cylinder head and the suction pipe so as to communicate with the inflow port. A second exhaust gas recirculation passage is formed by an exhaust gas outflow port provided at a joint between the intake pipe and the intake pipe, and a passage provided in the intake pipe so as to penetrate therethrough and communicate with the outflow port; The exhaust gas recirculation passage and the second exhaust gas recirculation passage are communicated via the EGR valve, and are formed integrally with each other during casting of the cylinder head and suction pipe to have a rough surface.
The present invention is characterized in that a plurality of ribs are provided at the inlet port of the exhaust gas recirculation passage.

[Effect]

In the present invention, by having the above means, a part of the exhaust gas from the exhaust port is recirculated to the intake passage of the intake pipe via the first exhaust gas recirculation passage, the EGR valve, and the second exhaust gas recirculation passage. During this time, the carbon in the exhaust gas is removed and purified by the plurality of ribs at the entrance of the first exhaust gas recirculation passage and the rough surfaces of these passages, which are still cast. Carbon adhering to the cylinder head is cleaned by removing the exhaust pipe and suction pipe from the cylinder head, and holes are drilled for press-fitting blind plugs into the cylinder head and suction pipe to form the conventional exhaust gas recirculation passage. Moreover, there is no need for work such as press-fitting a blind plug into this, and the structure is simplified.

〔Example〕

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings.

In the figure, numeral 1 is the cylinder head;
This cylinder head 1 is provided with an intake port 2 and an exhaust port 3 facing each other, and an intake pipe 6 from a carburetor 5 is airtightly connected to the intake port 2 side of the cylinder head 1 via a gasket 4. Similarly, a gasket 7 is installed on the exhaust port 3 side.
An exhaust pipe 8 is airtightly connected to the exhaust pipe 8 via.

The exhaust gas recirculation passage according to the present invention is located at the junction between the cylinder head 1 and the exhaust pipe 8.
A rectangular parallelepiped-shaped recess 9 that opens to the exhaust port 3 and communicates to the exhaust pipe 8 side is provided by casting the cylinder head 1 on the side, and the opening of the recess 9 to the exhaust port 3 has the following features: A plurality of ribs, for example, a comb-shaped fence 22 as shown in FIG. 4, is formed. and,
A hole 10 is made in the gasket 7 at a portion corresponding to the opening of the recess 9 on the exhaust pipe 8 side, and this is closed with the joint surface 8a of the fitting 8b of the exhaust pipe 8 to open the exhaust gas inflow port 11. It is beginning to form. A passage 1 passes through the inlet port 11, passes through the cylinder head 1, and passes through the suction pipe 6.
2 is formed integrally with the cylinder head 1 and suction pipe 6 in a straight line by roughening the surface roughness of the inner wall 12a with a pin type, etc., and this passage 12 and the inflow port 11 are Thus, a first exhaust gas recirculation passage 12b is formed. And the first
The valve body 14 of the EGR valve 13 is located at the opening of the exhaust gas recirculation passage 12b at the intake pipe 6.
The valve body 14 is airtightly joined and mounted via a gasket 15, and the passage 12b communicates with the inlet port 16 of the valve body 14.

Further, on the cylinder head 1 side of the joint between the cylinder head 1 and the suction pipe 6, a rectangular parallelepiped-shaped recess 19 that opens and communicates with the suction port 2 and the intake passage 6b is integrally formed when the cylinder head 1 is cast. The suction pipe 6 of this recess 19 of the gasket 4 is formed.
A hole 20 is made in a portion that coincides with the side opening, and this is closed with the joint surface 6a of the suction pipe 6 to form an exhaust gas outflow port 21. A second exhaust gas recirculation passage 17b is formed by the outflow port 21 and the passage 17 that is integrally formed in the suction pipe 6 when the suction pipe 6 is cast so as to penetrate therethrough and communicate with the outflow port 21. It's summery. This passage 17b communicates with the outlet port 18 of the valve body 14 of the EGR valve 13.

With this configuration, the exhaust port 3
First exhaust gas recirculation passage 12b, EGR valve 1
3. It communicates with the suction port 2 via a system path formed by the second exhaust gas recirculation passage 17b and the like.

For example, during high-load operation, a negative pressure signal is input from the carburetor to the EGR valve 13 and it is opened, so that part of the exhaust gas from the exhaust port 3 is returned to the intake port 2 through the above-mentioned system. However, this lowers the combustion temperature and reduces NOx contained in the exhaust gas. Also, at this time, the first and second exhaust gas recirculation passages 12b and 17b
Due to the rough surface of the inner wall of the exhaust gas, carbon in the recirculating exhaust gas adheres to it and is removed.

Further, in the above embodiment, the inflow port 11 is provided on the cylinder head 1 side, but this is provided on the exhaust pipe 8 side, and the outflow port 21 is provided on the cylinder head 1 side, but this is provided on the intake pipe side. Alternatively, only one of the inflow and outflow ports 11 and 21 may be provided at the joint with the cylinder head 1.

[Effect of idea]

As described above, according to the present invention, the first and second exhaust gas recirculation passages 12b and 17b are formed by casting the cylinder head 1 and the suction pipe 6, so that the above-mentioned blind plugs that were conventionally used for these can be replaced. Processing of holes for press-fitting and press-fitting of blind plugs are no longer necessary, and manufacturing and structure are greatly simplified. In addition, since these passages are used with the casting surface intact, leakage due to casting defects (holes) is reduced and the yield rate is improved, and the inner wall surface roughness allows for reflux. Carbon in the exhaust gas is removed to purify the exhaust gas, but the removal of this carbon is the first step.
This is also achieved by a plurality of ribs at the entrance of the inlet port of the exhaust gas recirculation passage. Furthermore, when the exhaust pipe 8 and suction pipe 6 are disassembled from the cylinder head 1, the inflow and outflow ports 11 and 21 as well as the first and second exhaust gas recirculation passages 12b and 17b are opened, making it easy to clean the inside thereof. obtain.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment of the device according to the present invention, FIGS. 2 and 3 are a cross-sectional view and a cross-sectional view of FIG. 1, and FIG. 4 is a perspective view of an inflow port recess. 1...Cylinder head, 2...Suction port, 3
...exhaust port, 6...intake pipe, 8...exhaust pipe,
11... Exhaust gas suction port, 12b... First
Exhaust gas recirculation passage, 13...EGR valve, 17
b...Second exhaust gas recirculation passage, 21...Exhaust gas outflow port.

Claims (1)

[Scope of utility model registration request] In a cylinder head with an exhaust port and an intake port facing each other, and an exhaust pipe and an intake pipe connected to these ports, respectively, the inflow of exhaust gas is provided at the joint between the cylinder head and the exhaust pipe. A first exhaust gas recirculation passage is formed by the port and a passage provided through the cylinder head and suction pipe so as to communicate with the inflow port, and an exhaust gas recirculation passage provided at the joint between the cylinder head and the suction pipe. A second exhaust gas recirculation passage is formed by the outflow port of the intake pipe and a passage provided in the suction pipe to communicate with the outflow port, and these passages communicate with each other via the EGR valve. , an exhaust gas recirculation system characterized in that the suction pipe is integrally formed at the time of casting to have a rough surface, and a plurality of ribs are provided at the inlet portion of the inflow port of the first exhaust gas recirculation passage. Device.