JPS6139072Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an exhaust purification device in which an exhaust purification catalyst is disposed immediately after an exhaust manifold.

For example, in the exhaust manifold of a four-cylinder internal combustion engine, by vaporizing the liquid fuel that forms in the riser part of the intake manifold during a cold start in a short time after the engine starts, the amount of air-fuel mixture distributed to each cylinder of the engine is uniform. In order to make the exhaust manifold and intake manifold contact each other at their riser parts, a heat control valve is installed near the riser part of the exhaust manifold, in other words, at the entrance of the expansion chamber of the exhaust manifold, in order to effectively heat the riser part. are arranged. When the engine is cold started, the heat control valve is set to the "closed" state, and the flow direction of the exhaust gas that was about to flow into the expansion chamber is changed by the heat control valve to the direction of the riser section. By bringing the exhaust gas into direct contact with the riser section, the heat exchange efficiency of the riser section is improved. Therefore,
When the heat control valve is in the "closed" state, the exhaust gas that has heated the riser part, due to its inertia, moves the center of the exhaust gas flow when it flows out from the expansion chamber of the exhaust manifold to the opposite side of the heat control valve. This causes a phenomenon that causes the body to move to.

On the other hand, there is now an increasing tendency to dispose a catalytic converter for exhaust gas purification immediately after the expansion chamber of the exhaust manifold. The reason for this is to shorten the activation time of the catalyst by the high-temperature exhaust gas immediately after passing through the exhaust manifold, and also to eliminate the need for a shield plate that would be required if the catalytic converter is placed downstream of the exhaust pipe. be.

Therefore, in an exhaust purification device that combines an exhaust manifold with a heat control valve and a catalytic converter, when the heat control valve is in the "closed" state, the flow of exhaust gas flowing out from the expansion chamber of the exhaust manifold is reduced. As a result of the center position moving in the opposite direction to the heat control valve, the exhaust gas does not hit the entire surface of the catalytic converter evenly, and only the catalyst in a part of the catalytic converter (on the opposite side of the heat control valve) deteriorates prematurely. This results in the disadvantage that the catalytic converter cannot be fully and effectively utilized.

The purpose of this invention is to prevent deterioration of only a portion of the catalyst in the catalytic converter in an exhaust gas purification system in which a catalytic converter is attached to an exhaust manifold having a heat control valve, and to utilize the catalytic converter sufficiently and effectively. The objective is to provide an exhaust gas purification device that can

The feature of the exhaust purification device of the present invention in its configuration is that when the heat control valve is in the "closed" state, the center position of the exhaust gas flow flowing out from the expansion chamber is aligned with the center position of the catalytic converter. In order to achieve this, the mounting position of the maniverter relative to the exhaust manifold is offset from the center of the heating riser section to the opposite side of the heat control valve. By eccentrically arranging the catalytic converter in this way, the center position of the exhaust gas flow and the center of the catalytic converter coincide with each other, so the exhaust gas hits the entire surface of the catalytic converter almost evenly, and the catalytic converter functions fully and effectively. Additionally, in order to make the catalytic converter function more effectively, the catalytic converter is tilted to the side opposite to the heat control valve with respect to the heating riser part, and the catalytic converter is tilted against the mounting surface of the exhaust manifold with respect to the cylinder block. It is also possible to tilt it to the opposite side. By installing the catalytic converter at an angle in this way, the exhaust gas flow can impinge on the catalytic converter at right angles, which further enhances the exhaust gas purification function and also reduces the back pressure caused by the presence of the catalytic converter. Since this is minimized, a decrease in the output of the internal combustion engine is prevented.

An embodiment of the present invention will be described below based on the drawings.

The figure shows a case in which the present invention is applied to a four-cylinder internal combustion engine, in which an exhaust manifold 1 is in contact with an intake manifold 2 at a heating riser portion 3. The exhaust manifold 1 has exhaust ports 1a for the first cylinder, exhaust ports 1b for the second cylinder, and exhaust ports 1c and 4 for the third cylinder.
Each cylinder has an exhaust port 1d, and the ends of these exhaust ports 1a, 1b, 1c, and 1d have mounting surfaces 1e and 1f for attaching to a cylinder head (not shown). 1g and 1h indicate separators. On the other hand, the intake manifold 2 has intake ports 2a,
2b, 2c, 2d, and these intake ports 2
The exhaust ports 1a, 2b, 2c and 2d are respectively connected to a cylinder head (not shown), similar to the exhaust ports 1a, 1b, 1c and 1d.

A heat control valve 4 operated by a bimetal (not shown) or the like is rotatably disposed near the heating riser section 3 of the exhaust manifold 1, and an expansion chamber 5 downstream of the heat control valve 4 is provided. An oxygen sensor 6 faces inside.

A catalytic converter 7 is attached to the downstream side of the expansion chamber 5 of the exhaust manifold 1, and the catalytic converter 7 is offset from the center of the heating riser section 3 by a certain distance on the opposite side from the heat control valve 4. Further, as shown in the second figure, the catalytic converter 7 is inclined by θ ₁ degree in the direction opposite to the heat control valve 4 with respect to a plane perpendicular to the upper surface of the heating riser section 3, and as shown in the third figure. It is inclined by _θ2 degrees in the opposite direction to the cylinder block (not shown) with respect to the mounting surfaces 1e and 1f of the exhaust manifold 1. Here, θ ₁ and θ ₂ degrees differ depending on the flow angle of the exhaust gas, but are approximately 15 degrees. The catalytic converter 7 is filled with an exhaust purifying catalyst (not shown), and 8 indicates a front pipe.

The action will be explained below.

When the engine is cold started, the heat control valve 4 is in the solid line position shown in Figure 2 (hereinafter referred to as the "closed" state), and is used to heat the exhaust gas flowing into the exhaust manifold 1 from the exhaust ports 1c and 1d. It will be guided in three directions of the riser section. This results in
Since the heating riser section 3 comes into direct contact with the exhaust gas guided by the heat control valve 4 in the "closed" state, it is heated in a short time after the engine starts, and the liquid fuel in the intake manifold 2 is heated. is vaporized and the amount of air-fuel mixture distributed to each cylinder is equalized.

When the heat control valve 4 is in the "closed" state, the heat flows into the expansion chamber 5 after colliding with the heating riser part 3, but due to the inertia of the exhaust gas, the exhaust gas flow is The center position will be closer to the exhaust ports 1a and 1b.
However, since the mounting position of the catalytic converter 7 is eccentric from the center of the heating riser section 3 to the side opposite to the heat control valve 4, the expansion chamber 7
The center position of the exhaust gas flow flowing out from the catalytic converter 7 substantially coincides with the center axis 7a of the catalytic converter 7.

Furthermore, as shown in FIG. 2, the catalytic converter 7 is inclined with respect to the heating riser part 3 in the opposite direction to the heat control valve 4, and the catalytic converter 7
As shown in the figure, the mounting surface 1e of the exhaust manifold 1,
1f in the opposite direction to the cylinder block (not shown), the exhaust gas flow can enter the catalytic converter 7 in a direction perpendicular to it.

Also, the heat control valve 4 is in the position shown by the imaginary line in Fig. 2 (hereinafter referred to as the "open" state).
, the exhaust ports 1a, 1b, 1c,
1d are mixed in the expansion chamber 5, so that the exhaust gas flow discharged from the expansion chamber 5 aligns its center with the central axis 7a of the catalytic converter 7, and It flows in a direction perpendicular to the opposite direction.

As explained above, according to the exhaust gas purification device of the present invention, since the heating riser part is installed eccentrically in the opposite direction of the heat control valve with respect to the exhaust manifold of the catalytic converter, the expansion chamber of the exhaust manifold This makes it possible to align the center of the flow of exhaust gas flowing out from the catalytic converter with the center of the catalytic converter, and as a result, the exhaust gas impinges almost evenly on the entire surface of the catalyst inside the catalytic converter, allowing the maniverter to function effectively. This effect can be obtained.

In addition, by installing the catalytic converter heating riser section and the exhaust manifold at an angle with respect to the mounting surface, it is possible to approximately align the central axis of the exhaust gas flow with the central axis of the catalytic converter. flows into the catalytic converter in a direction perpendicular to the catalytic converter, further enhancing the exhaust purification function and minimizing the increase in back pressure due to the presence of the maniverter, which also has the effect of preventing a drop in the output of the internal combustion engine. can get.

[Brief explanation of the drawing]

Figure 1 is a plan view of the exhaust purification device of the present invention, Figure 2 is a plan view of the exhaust purification device of the present invention;
The figure is a front view of FIG. 1, and FIG. 3 is a right side view of FIG. 2. 1...Exhaust manifold, 1a, 1b, 1c, 1
d...Exhaust port, 1e, 1f...Exhaust manifold mounting surface, 1g, 1h...Separator, 2...
Intake manifold, 2a, 2b, 2c, 2d... Intake port, 3... Heating riser section, 4... Heat control valve, 5... Expansion chamber, 6... Oxygen sensor, 7... Catalytic converter, 8... ...Front pipe.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) In an exhaust purification device in which a heat control valve is disposed near a heating riser part of an exhaust manifold and a catalytic converter is disposed immediately after the exhaust manifold, the catalytic converter is An exhaust purification device characterized in that the heating riser section is eccentrically arranged from the center of the heating riser section to the opposite side of the heat control valve. (2) The exhaust gas purification device according to claim 1, wherein the catalytic converter is inclined in a direction opposite to the heat control valve with respect to the heating riser portion. (3) Utility model registration claim 1, in which the catalytic converter is inclined in a direction opposite to the cylinder block with respect to the mounting surface of the exhaust manifold.
The exhaust gas purification device according to item 1 or 2.