JP2530310Y2 - Catalytic converter with flange integrated with O2 sensor - Google Patents

Description

[Detailed description of the invention]

[0001]

INVENTION The present invention relates to a O ₂ sensor integrated flanged catalytic converter in the converter mounting flange to the exhaust manifold is provided a mounting portion of the O ₂ sensor.

[0002]

2. Description of the Related Art Generally, a catalytic converter for purifying exhaust gas discharged from an engine is mounted on a vehicle exhaust system. Such a catalytic converter uses a catalyst to oxidize carbon monoxide and hydrocarbons in exhaust gas to convert them into harmless carbon dioxide gas and water vapor. Conventionally, an O ₂ sensor for detecting the oxygen concentration in the exhaust gas is mounted on the vehicle exhaust system, and when the amount of oxygen necessary for the oxidation-reduction reaction by the catalyst becomes insufficient, the control means which inputs the signal of the O ₂ sensor is used. The ejector supplies secondary air into the catalytic converter in accordance with the above command to promote the oxidation-reduction reaction.

FIG. 8 shows a conventional vehicle exhaust system in which a pre-converter 3 is directly connected to a downstream end of a dual exhaust manifold 1. In such an exhaust system, the pre-converter 3 temporarily removes carbon monoxide in the exhaust gas. The hydrocarbons are oxidized to increase the exhaust gas temperature, thereby increasing the activation temperature of the catalyst in the main converter mounted on the downstream side to promote the purification of exhaust gas.

[0004] Thus, in the above exhaust system, conventionally, the boss mounting hole 7 drilled in the shell 5 of the pre-converter 3 as shown in FIG. 9, O ₂ mounting boss of the sensor 9 to the boss attachment hole 7
Was welded. Then, the O ₂ sensor is inserted into and screwed into the mounting boss 9 so that the insertion side end of the O ₂ sensor is desired near the upstream end surface 11a of the catalyst carrier 11, and the secondary side is inserted into the downstream main converter based on the detected value. Air is being introduced. still,
In the figure, reference numeral 13 denotes a flange for mounting the pre-converter 3.

[0005]

[Problems to be solved by the present invention]
_In the conventional structure in which the _two sensors are mounted near the upstream end surface 11a of the catalyst carrier 11, the exhaust gas flowing from the exhaust manifold 1 interferes with the exhaust gas that has bounced off the upstream end surface 11a of the catalyst carrier 11. And the oxygen concentration cannot be detected accurately. In other words, in the exhaust gas that rebounds on the catalyst carrier 11, the oxygen concentration is slightly changed by the action of the catalyst on the upstream end face 11a side of the catalyst carrier 11, and the catalyst carrier 11 becomes a flow path resistance. Exhaust gas is upstream end surface 1
Since the exhaust gas stays in the shell 5a on the 1a side, the exhaust gas affects new exhaust gas flowing from the exhaust manifold 1, and an accurate oxygen concentration in the exhaust gas cannot be detected.

In Japanese Utility Model Laid-Open Publication No. 63-71409,
As shown in FIG. 10, the mounting boss portion 19 of the O ₂ sensor is formed integrally with the mounting flange 17 provided at the collecting portion of the downstream end of the dual exhaust manifold 15, the O ₂ sensor to the mounting boss portion 19 A mounting structure is disclosed.
Thus, if the O ₂ sensor is attached to the mounting flange 17 on the exhaust manifold 15 side to secure the distance from the catalyst carrier, the exhaust gas that has bounced off the upstream end face of the catalyst carrier and the new exhaust gas from the exhaust manifold 15 can be obtained. It is possible to prevent interference with the exhaust gas.

However, the O ₂ sensor is mounted on the mounting boss 19.
Through the exhaust passages 15a, 15a of the exhaust manifold 15.
5b, the two exhaust passages 15a,
Even if the total oxygen concentration in the exhaust gas flowing into the catalytic converter from 15b is sufficient for the oxidation-reduction reaction in the catalytic converter,
When the oxygen concentration of the exhaust gas in a is slightly insufficient,
The O ₂ sensor may detect that the exhaust gas in the exhaust passage 15a is short of oxygen.

Therefore, it is preferable that the O ₂ sensor be mounted downstream of the outlet collecting portion of the dual exhaust manifold 15. However, if the O ₂ sensor is inserted into the shell 5 of the pre-converter 3 as shown in FIG. 9, an accurate oxygen concentration in the exhaust gas cannot be detected. The present invention has been devised in view of such circumstances, and focuses on a converter mounting flange connected to the downstream side of an outlet assembly of an exhaust manifold, and provides an O ₂ sensor mounting portion on the mounting flange. Accordingly, an object of the invention to provide an O ₂ sensor integrated flanged catalytic converter that enables accurate detection of the oxygen concentration in the exhaust gas by the O ₂ sensor.

[0009]

In order to achieve the above object, a catalytic converter having an O ₂ sensor integrated flange according to the present invention is provided by directly connecting the catalytic converter to a downstream end of a dual exhaust manifold via a converter mounting flange. In the connected vehicle exhaust system, a notch for inserting an O ₂ sensor is provided at the upstream end of the shell of the catalytic converter,
The converter mounting flange, in which is provided integrally with the O ₂ sensor mounting boss portion abutting the outer periphery of the shell covering the-out the cut-out.

[0010]

According to the present invention, the O ₂ sensor mounting boss has O
By mounting _two sensors, O ₂ sensor trims the converter mounting flange and the O ₂ sensor detects the oxygen concentration in the exhaust gas flowing in from the exhaust manifold. Then, the exhaust gas flowing into the catalytic converter even rebounding is part when the upstream side end face of the catalyst carrier, the present invention is to secure the O ₂ sensor compared with the conventional example long distance to the upstream side end surface Therefore, the risk of interference of the exhaust gas flowing from the exhaust manifold with the exhaust gas that bounces back on the upstream end surface of the catalyst carrier is reduced. possibility even fewer ₂ sensor affected, in addition, the present invention is I or mutually俟be those wearing the O ₂ sensor downstream of the outlet collecting portion of the dual of the exhaust manifold, the O ₂ sensor exhaust The oxygen concentration in the gas is accurately detected.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. The same components as those in the conventional example shown in FIGS. 8 and 9 are denoted by the same reference numerals. In FIG.
Is a pre-converter, and the pre-converter 21 is shown in FIG.
As in the conventional pre-converter 3 shown in FIG. 1, the catalyst carrier 11 is incorporated in a shell 23 formed by a pair of upper and lower split shells 23a and 23b being joined to each other, and a converter mounting bracket attached to an upstream end thereof. The dual exhaust manifold 1 is connected to a downstream end of the dual exhaust manifold 1 via a flange (hereinafter referred to as “mounting flange”) 25.
Then, as shown in FIG. 2 and FIG.
Is formed with a U-shaped notch 27 through which the O ₂ sensor is inserted.

On the other hand, as shown in FIGS. 4 and 5, on the upper surface 25a of the mounting flange 25, an O ₂ sensor mounting boss portion (hereinafter referred to as “boss portion”) 29 having a hexagonal cross section is provided. An O ₂ sensor mounting hole 33 whose inner periphery is threaded as shown in FIG. 6 is formed at the center of the O ₂ sensor mounting hole 33.
The boss portion 29 is provided with the mounting flange 2 as shown in FIG.
When the shell 5 is attached to the upstream end of the shell 23, a contact surface 29a that comes into contact with the outer periphery of the split shell 23a is formed along the outer shape of the upstream end of the split shell 23a. The boss 29 covers the notch 27 when the contact surface 29a contacts the outer periphery of the split shell 23a.

Then, while covering the notch 27 with the boss portion 29 in this way, the mounting flange 25 and the boss portion 29 are connected to the shell 2.
If screwed 3 of the O ₂ sensor is welded to the outer periphery O ₂ sensor mounting hole 33 of the boss portion 29 protrudes O ₂ sensor is inserted through the notch 27 the insertion side end within the shell 23, O ₂
The sensor will be attached to the pre-converter 21. Since the present embodiment is configured as described above, if the pre-converter 21 is directly connected to the downstream end of the exhaust manifold 1 via the mounting flange 25 and the O ₂ sensor is inserted and screwed into the boss portion 29, An O ₂ sensor is attached to the converter mounting flange 25, and the O ₂ sensor detects the oxygen concentration in the exhaust gas flowing from the exhaust manifold 1.
Then, based on the detection value of the O ₂ sensor, so that the downstream side of the main converter secondary air is introduced.

At this time, even if the exhaust gas flowing into the pre-converter 21 hits the upstream end face 11a of the catalyst carrier 11 and a part of the exhaust gas rebounds, the present embodiment has a higher O.sub.2 than the conventional example shown in FIG. _{(2) Since} the distance between the sensor and the upstream end surface 11a is long, the upstream end surface 1
An exhaust gas bouncing against the 1a, with interference with the exhaust gas flowing in from the new exhaust manifold 1 is reduced, O ₂ sensor is affected by the exhaust gas staying in the upstream end surface 11a of the shell 23 There is little danger, and this embodiment is O.sub.0 compared to the conventional example shown in FIG.
_{The two} sensors are mounted on the downstream side of the outlet gathering part of the exhaust manifold 1 which is dualized.
_Two sensors accurately detect the oxygen concentration in the exhaust gas.

Therefore, according to the present embodiment, O
Accurate detection of oxygen concentration in exhaust gas by _two sensors became possible, and purification of exhaust gas was surely achieved. Further, according to this embodiment, the boss 9 of another part as shown in FIG.
It is no longer necessary to separately prepare and weld this to the shell, and the number of parts of the boss and the number of mounting steps for the boss can be reduced. In addition, according to the present embodiment, by protruding the boss portion 29 integrally with the mounting flange 25, there is an advantage that a secondary effect such as improvement in rigidity of the mounting flange 25 can be expected. .

In the above embodiment, the present invention is applied to a pre-converter, but the present invention is also applicable to a manifold converter directly connected to an exhaust manifold.

[0017]

As described above, according to the present invention, the oxygen concentration in the exhaust gas can be detected more accurately by the O ₂ sensor than in the conventional case, and the exhaust gas can be reliably purified. Was. Further, according to the present invention, it is not necessary to separately prepare a boss of another part and weld it to the shell of the catalytic converter as in the conventional case shown in FIG. 9, so that the number of parts and the number of mounting steps can be reduced. It became.

In addition, according to the present invention, by integrally projecting the boss portion on the mounting flange, there is an advantage that a secondary effect such as improvement in rigidity of the mounting flange can be obtained.

[Brief description of the drawings]

FIG. 1 is a side view of a pre-converter according to an embodiment of the present invention.

FIG. 2 is a plan view of a split shell.

FIG. 3 is a side view of a shell of the pre-converter.

FIG. 4 is a plan view of a mounting flange.

FIG. 5 is a front view of a mounting flange.

6 is a sectional view taken along line VI-VI of FIG.

FIG. 7 is a plan view of a pre-converter.

FIG. 8 is a partial perspective view of a conventional vehicle exhaust system.

FIG. 9 is a partial perspective view of a conventional pre-converter provided with a boss for mounting an O ₂ sensor.

FIG. 10 is a perspective view of a mounting flange provided at a collecting portion at a downstream end of the exhaust manifold.

[Explanation of symbols]

 Reference Signs List 11 catalyst carrier 21 pre-converter 23 shell 25 mounting flange 27 notch 29 boss

Claims (1)

(57) [Scope of request for utility model registration] An upstream end of a catalytic converter shell (23) in a vehicle exhaust system in which a catalytic converter is directly connected to a downstream end of a dual exhaust manifold (1) via a converter mounting flange (25). the cutout for the O ₂ sensor inserted provided with a (27), the converter to the mounting flange (25), the O ₂ sensor mounting boss portion abutting the outer periphery of-out the cut-out (27) covering the shell (23) (2
9) A catalytic converter with a flange integrated with an O ₂ sensor, wherein the catalytic converter is provided integrally.