JPS6335155Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an exhaust manifold for an internal combustion engine in which a detector for exhaust gas analysis is inserted.

Conventional dual port exhaust manifold 1
In this case, as shown in FIGS. 1 to 3, branch pipes 2, 3, 4, and 5 are connected to the first, second, third, and fourth cylinders (not shown), and the first cylinder and the fourth cylinder are connected to each other. It consists of a collecting pipe 6 in which the branch pipes 2 and 5 connected to the cylinders are collected downstream, and a collecting pipe 7 in which the branch pipes 3 and 4 connected to the second and third cylinders are collected in the downstream, and the branch pipe 2, Secondary air supply ports 8 and 8A are provided upstream of the air pump 5. In the exhaust manifold 1 having the above configuration, the oxygen gas sensor 10, which is a detector for exhaust gas analysis, is inserted through the mounting boss 9 into the collecting pipe 7 where the branch pipes 3 and 4 are gathered. The oxygen gas sensor 10 has a configuration in which a standard substance is filled in a solid electrolyte container with electrode layers formed on the front and back surfaces, a reference electrode and a measurement electrode, and the measurement electrode has a catalyst layer that promotes an oxidation reaction. However, in order to accurately detect the oxygen concentration in exhaust gas, a high temperature above a certain level is required. In the above configuration, exhaust gas from each cylinder passes through each branch pipe 2, 3, 4, 5 to collecting pipes 6, 7.
The oxygen concentration in the exhaust gas is detected by the oxygen gas sensor 10 in the collecting pipe 7, and then the exhaust gas is discharged through an exhaust pipe (not shown).
In order to burn harmful components such as CO and HC in the exhaust manifold 1, as mentioned above, the exhaust gas temperature is high and the secondary air supply port is easy to install.
Secondary air supply ports 8, 8A are provided as far upstream as possible in the branch pipes 2, 5 of the cylinder and the fourth cylinder to supply air into the exhaust gas. As mentioned above, the secondary air supply ports 8, 8A are usually provided as far upstream as possible from the branch pipes 2, 5, so at the location of the collecting pipe 6, the exhaust gas is supplied from the secondary air supply ports 8, 8A. The oxygen gas sensor 10 is connected to the branch pipes 3 and 4 connected to the second and third cylinders, as described above, because the second air is already mixed, which hinders accurate detection of the oxygen concentration in the exhaust gas. The oxygen gas sensor 10 is inserted into the collecting pipe 7. However, with the above configuration, the oxygen concentration in the exhaust gas cannot be accurately detected in engines where the oxygen concentration in the exhaust gas differs significantly between cylinders, and the mixture ratio of intake gas cannot be appropriately controlled accordingly. I end up not being able to do anything. Therefore, as shown in FIG.
There is also provided a semi-dual port type exhaust manifold in which an oxygen gas sensor 10 is inserted through a mounting boss 9 at this position. However, even with this semi-dual port type exhaust manifold, the influence of exhaust gas from the collecting pipe 6 mixed with secondary air cannot be avoided, and on the contrary, the influence of the exhaust gas from the collecting pipe 6 and the collecting pipe 7
Due to the mixing of the exhaust gas with the engine, exhaust interference between the cylinders cannot be completely eliminated, resulting in the disadvantage that high engine output cannot be obtained.

The purpose of this invention is to solve the above-mentioned conventional problems and perform exhaust gas analysis in the exhaust manifold of an internal combustion engine with high accuracy. The main point is to sample and submit it for analysis.

The present invention will be explained with reference to an embodiment shown in FIG. 5 and below. In the exhaust manifold 11,
13, 14, 15 are first, second, not shown, respectively.
These are branch pipes connected to the third and fourth cylinders, and the branch pipes 12 and 15 are collected into a collecting pipe 16 downstream, and the branch pipes 13 and 14 are connected to a collecting pipe 17 downstream.
Gather at. Further, secondary air supply ports 18, 18A are provided on the upstream side of branch pipes 12, 15 connected to the first cylinder and the fourth cylinder, respectively, and secondary air supply ports 18, 18A are provided in the collecting pipe 17 connected to the second cylinder and the third cylinder, respectively. An oxygen gas sensor 20 is inserted through a mounting boss 19. Furthermore, branch pipes 12 and 15 are connected to the first cylinder and the fourth cylinder.
Bypass exhaust circuits 21 and 21A are separated from the upstream sides of the secondary air supply ports 18 and 18A, respectively, and the bypass exhaust circuits 21 and 21A are assembled downstream to form a collection section 22 at the oxygen gas sensor 20 position. A separation wall 23 is installed inside the gathering part 22, and branch pipes 13 are connected to the second cylinder and the third cylinder, respectively.
Fourteen bypass exhaust ports 24, 24A are separated, and thus the collecting section 22 communicates with the collecting pipe 17 via the bypass exhaust ports 24, 24A.

In the above configuration, when the internal combustion engine is operated, high-temperature exhaust gas from each cylinder (not shown) is transferred to each branch pipe 12, 13, 1 via a cylinder head (not shown).
In the branch pipes 12 and 15 that flow into the exhaust gases 4 and 15 and connect to the first and fourth cylinders, secondary air is supplied to the exhaust gas from the secondary air supply ports 18 and 18A, thus reducing CO in the exhaust gas. , HC, etc. are burned and reach the collecting pipe 17, and in the branch pipes 13 and 14 connected to the second and third cylinders, the secondary air is not replenished and reaches the collecting pipe 16. It is discharged to an exhaust pipe (not shown). On this occasion,
Branch pipes 12 connected to the first cylinder and the fourth cylinder, respectively;
15, part of the exhaust gas from upstream of the secondary air supply ports 18, 18A is transferred to the bypass exhaust circuit 21,
21A, and the exhaust gas thus reaches the collection part 22 without mixing with secondary air, and is further connected to the branch pipes 13 and 1 to the second and third cylinders.
4, a part of the exhaust gas is diverted to the bypass exhaust ports 24, 24A by the separation wall 23, and thus, in the collection part 22, the exhaust gas from the first to fourth cylinders is a high-temperature gas that is not mixed with secondary air. In this state, the same amount is mixed for each cylinder. Therefore, if the oxygen concentration of the exhaust gas in the collecting portion 22 is detected by the oxygen gas sensor 20, the value will substantially match the original oxygen concentration of the engine. Therefore, the mixture ratio of intake gas can be appropriately controlled based on the detected value. In addition, branch pipes 1 are connected to the first cylinder and the fourth cylinder, respectively.
Since the collecting pipes 16 of the 2nd and 15th cylinders and the collecting pipes 17 of the branch pipes 13 and 14 connected to the 2nd and 3rd cylinders, respectively, are separated, there is no exhaust interference between the cylinders.
Therefore, there is no reduction in output due to exhaust interference.

As described above, in the present invention, branch pipes communicating with the first cylinder and the fourth cylinder, respectively, and branch pipes communicating with the second cylinder and the third cylinder, respectively, are assembled to form two collecting pipes. In a dual-port exhaust manifold for a tracheal internal combustion engine, branch pipes communicating with the first cylinder and the fourth cylinder are each provided with a secondary air supply port on the upstream side, and each secondary air supply port is provided on the upstream side of the secondary air port. The bypass exhaust circuit is separated, and the bypass exhaust circuit is collected in a collection pipe of branch pipes that communicate with the second and third cylinders, so that high-temperature exhaust gas that is not mixed with secondary air is collected in the collection part. Furthermore, by installing a separation wall in the collecting part, a bypass exhaust port of the branch pipe communicating with the second cylinder and the third cylinder is formed, so that the exhaust gases from each cylinder are mixed in equal amounts. Thus, if gas analysis is performed using a detector for exhaust gas analysis at the collection point, the engine's original exhaust gas composition can be accurately detected, and the detected value can be used to determine the mixture of intake gas. It is possible to properly control the operating factors of the engine such as the ratio, and the
Since the collecting pipes of the branch pipes that connect to the cylinders and the collecting pipes of the branch pipes that connect to the second and third cylinders are separated, there is no exhaust interference between the cylinders, so there is no exhaust interference. There is no reduction in output.

[Brief explanation of the drawing]

Figures 1 to 3 relate to conventional examples;
Fig. 1 is a perspective view, Fig. 2 is a sectional view taken along line AA' in Fig. 1, Fig. 3 is a sectional view taken along line BB' in Fig. 1, and Fig. 4 is a sectional view taken along line BB' in Fig. 1. Corresponding cross-sectional view. 5 to 8 relate to an embodiment of the present invention, in which FIG. 5 is a perspective view, FIG. 6 is a sectional view taken along line C-C' in FIG. 5, and FIG. 7 is taken along line D-- in FIG. D' sectional view and FIG. 8 are EE' sectional views shown in FIG. 5 and FIG. 7. 1, 11 in the figure... Exhaust manifold, 2, 3,
4, 5, 12, 13, 14, 15...branch pipe,
6, 7, 16, 17...collecting pipe, 8, 8A, 1
8, 18A... Secondary air supply port, 10, 20...
Oxygen gas sensor, 21, 21A... Bypass exhaust circuit, 22... Gathering part, 23... Separation wall, 24,
24A, 61...exhaust port.

Claims (1)

[Scope of utility model registration request] a branch pipe connected to the first cylinder and the fourth cylinder, respectively;
In a dual-port exhaust manifold for a four-cylinder internal combustion engine, in which branch pipes connected to the second and third cylinders respectively come together to form two collecting pipes, the branch pipes connect to the first cylinder and the fourth cylinder, respectively. A secondary air port is provided on the upstream side of the pipe, and a bypass exhaust circuit is separated on the upstream side of the secondary air port, and the bypass exhaust circuit has a branch connected to the second cylinder and the third cylinder, respectively. By connecting the pipes to a collecting pipe and further providing a separation wall in the collecting part, a bypass exhaust port is formed for the branch pipes connected to the second cylinder and the third cylinder, respectively, and the collecting part is provided with an exhaust gas. An exhaust manifold for an internal combustion engine, characterized in that a detector for gas analysis is installed.