JPH068548Y2 - Exhaust gas component detection sensor - Google Patents

Description

Detailed Description of the Invention A. Purpose of the Invention (1) Industrial Application Field of the Invention The present invention is directed to an exhaust gas attached to an exhaust pipe of an internal combustion engine, in which a detection section is covered with a cylindrical cover having an exhaust gas passage hole, and the cover faces the exhaust gas passage. The present invention relates to a component detection sensor.

(2) Conventional Technology Conventionally, as such an exhaust gas component detection sensor, for example, oxygen sensors have been disclosed in Japanese Utility Model Publication No. 56-27394 and Japanese Utility Model Publication No. 57-1.
No. 12949, Japanese Utility Model Publication No. 53-157210, and the like.

(3) Problems to be Solved by the Invention However, in the above-mentioned conventional one, the cover is formed with a circular cross section, so that the flow resistance to exhaust gas is relatively large, and therefore the output of the internal combustion engine decreases. Was.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide an exhaust gas component detection sensor that reduces the flow resistance and accordingly suppresses the output loss of the internal combustion engine as much as possible.

B. Configuration of the Invention (1) Means for Solving the Problems According to the present invention, the cross-sectional shape of the cover is formed in a long streamline shape in the direction along the exhaust gas flow direction of the exhaust gas passage.

(2) Action By making the cross-sectional shape of the cover streamlined, the exhaust gas flow resistance is reduced, and thereby the output loss of the internal combustion engine can be suppressed to a small level.

(3) Embodiment Hereinafter, one embodiment of the present invention will be described with reference to the drawings. First, in FIG. 1, an exhaust manifold 1 as an exhaust pipe of a four-cylinder internal combustion engine E has an exhaust gas component detection sensor at its collecting portion 1a. The oxygen sensor 2 is attached.

In FIG. 2, the oxygen sensor 2 has a detecting portion 3 covered with a tubular cover 4, and a collecting portion 1 a of the exhaust manifold 1.
The cover 4 is exposed to the exhaust gas passage 6 through the mounting hole 5 provided in the mounting hole 5, and the flange 7 is mounted by the bolt 8 so as to be coupled to the outer surface of the collecting portion 1a.

In FIG. 3, the cover 4 has a cross-sectional shape that is a streamline shape that is long along the flow direction 9 of the exhaust gas flowing in the exhaust gas passage 6, for example, an elliptical shape whose major axis is the direction along the flow direction 9. It is formed.

Further, in order to allow the exhaust gas to flow into the cover 4 and come into contact with the detection unit 3, the cover 4 is provided with a plurality of exhaust gas circulation holes 10
Is drilled.

Next, the operation of this embodiment will be described. By making the cross-sectional shape of the cover 4 an elliptical shape that is long along the flow direction 9, the flow resistance of exhaust gas is reduced. That is, the exhaust gas smoothly flows along the cover 4,
Since the vortex is less likely to occur behind the cover 4, the flow resistance is reduced. As a result, since the oxygen sensor 2 is attached to the exhaust manifold 1, the output loss of the internal combustion engine E can be reduced.

Here, when the minor axis of the cover 4 is a and the major axis is b,
The result of confirming the change of the output loss by the change of b / a by the experiment is shown in FIG. This experiment was carried out at a medium speed of the internal combustion engine E, but compared with the conventional one in which b / a = 1, that is, the cover 4 has a circular cross-sectional shape, it has an elliptical shape according to the present invention. It is clear that the output loss can be suppressed to a small level by using the cover 4 described above. In particular, when b / a is 1.5 or more, the output loss reducing effect is large, but it is considered difficult to manufacture b / a of 2.5 or more in terms of production technology. 2.5
Is desirable. The experimental results shown in FIG. 4 show comparisons when the projected areas orthogonal to the flow direction 9 are the same.

As another embodiment of the present invention, as shown by the chain double-dashed line in FIG. 3, the cover 4'may have a teardrop shape in cross section, which further reduces the flow resistance and reduces the output loss. It can be kept small.

C. As described above, according to the present invention, the cross-sectional shape of the cover is
Since the exhaust gas passage is formed in a long streamline shape along the exhaust gas flow direction, the exhaust gas flow resistance can be reduced and the output loss of the internal combustion engine can be reduced.

[Brief description of drawings]

The drawings show one embodiment of the present invention. FIG. 1 is a simplified plan view showing the mounting position of an oxygen sensor, FIG. 2 is an enlarged sectional view taken along line II-II of FIG. 1, and FIG. 2 is a sectional view taken along line III-III in FIG. 2, and FIG. 4 is a graph showing experimental results. 1 ... Exhaust manifold as exhaust pipe, 2 ... Oxygen sensor as exhaust gas component detection sensor, 3 ... Detection unit,
4, 4 '... Cover, 6 ... Exhaust gas passage, 9 ... Flow direction, 10 ... Exhaust gas flow hole, E ... Internal combustion engine

Claims (1)

[Scope of utility model registration request] 1. An exhaust gas component detection sensor, wherein the detection part is covered with a cylindrical cover having exhaust gas passage holes, and the exhaust gas component detection sensor is mounted on an exhaust pipe of an internal combustion engine with the cover facing the exhaust gas passage. An exhaust gas component detection sensor having a streamlined shape, which is long in a direction along an exhaust gas flow direction of an exhaust gas passage.