JPH0619074Y2 - Exhaust gas sample extractor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an exhaust gas sample extracting device for analyzing exhaust gas from an engine body.

[Conventional technology]

In general, as a means for analyzing the components of the exhaust gas discharged from the engine body, there is known one in which the whole exhaust gas discharged from the engine body is introduced into the flow pipe for analysis, but the entire device is Due to the difficulty of increasing the size of the engine, a part of the exhaust gas discharged from the engine body is extracted and used for analysis to reduce the size of the entire apparatus.

In this case, a small-diameter ejector that forms a venturi is provided in the middle of the flow pipe so that air is introduced from the air compressor to the flow pipe through the air filter, and the discharge end of the intake pipe is arranged in this ejector. The exhaust gas in the exhaust pipe is sucked through the intake pipe while utilizing the pressure drop of the air flowing in the ejector. Then, the air and the exhaust gas are mixed in the flow pipe, and the diluted exhaust gas is sent to the exhaust gas analyzer through the intake pipe to analyze the exhaust gas.

However, in the above-mentioned configuration, since a part of the exhaust gas in the exhaust pipe is sucked by utilizing the pressure drop phenomenon of the air due to the ejector formed in the flow pipe, Regardless of the change in the number of revolutions, that is, the change in the flow rate of the exhaust gas flowing in the exhaust pipe, the flow rate of the exhaust gas introduced into the flow pipe through the intake pipe is always kept constant. Therefore, even if the rotation speed of the engine body changes, the exhaust gas concentration in the flow pipe does not change, so that it is not possible to analyze the exhaust gas corresponding to the change in the rotation speed of the engine body.

Therefore, an exhaust gas sample extracting device has been developed which can downsize the entire device and can analyze the exhaust gas in response to changes in the number of revolutions of the engine body.

For example, FIGS. 3 to 9 show an exhaust gas sample extracting device disclosed in Japanese Utility Model Publication No. 60-127420.

FIG. 3 shows a schematic configuration of the whole analyzer equipped with an exhaust gas sample extracting device, 31 is an engine body, 32 is an exhaust pipe of the engine body 31, and the exhaust pipe 32 has an exhaust diffuser 33 One end is connected. As shown in FIGS. 4 to 6, the exhaust diffuser 33 is formed in a substantially cylindrical shape with its main body 34 gradually expanding in diameter, and the flange portion of the exhaust pipe 32 is provided at one end of the main body 34.
A flange portion 34a connected to 32a is provided, and a flange portion 35b connected to the flange portion 35a of the proportional divider 35 at the other end.
Is provided. Furthermore, this exhaust diffuser 33
In the main body 34, the discharge end on the proportional divider 35 side is formed in an octagonal shape.

Further, the proportional divider 35 is formed by a substantially cylindrical case 36 and a plurality of thin tubes 37 having the same flow path resistance as shown in FIGS. In this case, the thin tube 37
The respective suction ends are arranged in an octagonal uniform distribution according to the shape of the discharge end of the exhaust diffuser 33 (see FIG. 5).

Further, an intake reducer 38 is arranged in a state of being separated and opposed to the discharge end of each thin tube 37 of the proportional divider 35.

An intake blower 39 is connected to the intake reducer 38, and the exhaust gas guided from the engine body 31 through the exhaust pipe 32, the exhaust diffuser 33, and the thin tubes 37 of the proportional divider 35 is introduced into the intake blower 39 via the intake reducer 38.
It is supposed to be inhaled. Further, at this time, the exhaust gas sent from the discharge end of the exhaust diffuser 33 is uniformly divided by the proportional divider 35 and introduced into each thin tube 37.

Further, the sample probe 40 is formed by one of the thin tubes 37 forming the proportional divider 35. The sample probe 40 has a portion other than the suction end portion extended to the outside of the case 36 of the proportional divider 35, and exhaust gas proportional to the exhaust gas flow rate is taken out by the sample probe 40. . A discharge end 41 of the sample probe 40 is inserted inside a flow pipe (dilution tunnel) 42 for diluting exhaust gas.

The sample probe 40 includes a suction portion 40a fixed to the proportional divider 35 side, an injection nozzle portion 40b fixed to the flow pipe 42 side, and a connecting portion connecting the suction portion 40a and the injection nozzle portion 40b. 40c, the back pressure P ₁ of the discharge end 41 of the sample probe 40 and the discharge end back pressure P ₂ of each thin tube 37 of the proportional divider 35 are substantially constant values, and the pressure difference between them is also the same. It is very small compared to the pressure difference with the inlet pressure P ₀ .

On the other hand, the distribution pipe 42 is provided with a diffusion orifice 43 and a critical flow velocity venturi 44, respectively,
The suction blower 45 is connected to the venturi 44 side,
Air is sucked into the flow pipe 42 through the air filter 46 by the suction blower 45.

Further, the discharge end 41 of the sample probe 40 is arranged closer to the air filter 46 than the diffusion orifice 43.
A mixing chamber 47 for the exhaust gas discharged from the sample probe 40 and the air introduced through the air filter 46 is formed in the flow pipe 42 upstream of the diffusion orifice 43. The exhaust gas mixed and diluted with air is diverted to the venturi 44 side via the diffusion orifice 43.

In the vicinity of the venturi 44 in the distribution pipe 42,
One end of the intake pipe 48 is inserted. This intake pipe 48
The other end is connected to an exhaust gas analyzer 50 via a bag 49, and the exhaust gas analyzer 50 is used to analyze the components of the exhaust gas. In addition,
Reference numeral 51 is a particulate collection filter holder, 52
Shows a constant sample flow controller and gas analyzer.

With the above configuration, the exhaust gas derived from the engine body 31 via the exhaust pipe 32 and the exhaust diffuser 33 is introduced into each thin tube 37 of the proportional divider 35 and the sample probe 40.

At this time, the exhaust gas sent out from the exhaust diffuser 33 respectively flows into each thin tube 37 of the proportional divider 35 and the sample probe 40 in a uniformly divided state.

Therefore, even if the rotation speed of the engine body 31 changes, the
Since an exhaust gas sample having a flow rate proportional to the flow rate of the exhaust gas discharged from the sample probe 4 is introduced,
By setting 0, an exhaust gas sample proportional to the exhaust gas amount of the engine body 31 can be taken out.
It is possible to analyze the exhaust gas corresponding to the change in the rotation speed of 1.

[Problems to be solved by the invention]

However, in the exhaust diffuser 33 in the conventional exhaust gas sample extracting device described above, the exhaust pipe 32
There is a problem that the exhaust gas flow from the above is not sufficiently evenly distributed to each thin tube 37 of the proportional divider 35.

Further, if some setting conditions are not given to the shape and size of the thin tube, there is a possibility that the exhaust gas cannot be taken out in proportion to the thin tube or the exhaust gas can be taken out through the sample probe under the analysis conditions of the exhaust gas.

The present invention is intended to solve these problems, and enables the exhaust gas to be evenly distributed to each thin tube, and also to guide the exhaust gas that meets the conditions that can be analyzed to the exhaust gas analyzer. It is an object of the present invention to provide an exhaust gas sample extracting device.

[Means for solving problems]

Therefore, the exhaust gas sample extraction device of the present invention is
It is equipped with a proportional divider that consists of a plurality of thin tubes arranged in the middle of the exhaust passage through which the exhaust gas from the engine body flows, and divides the exhaust gas in the exhaust passage evenly into each thin pipe of the proportional divider. Exhaust gas that has a diffuser for evenly guiding the exhaust gas, forms a sample probe by any of the thin tubes, and can take out an exhaust gas sample proportional to the flow rate of the exhaust gas in the exhaust passage by the sample probe. In the sample extracting device, the diffuser is provided with a straight pipe portion, and the plurality of thin tubes are set to have substantially the same length, inner diameter, and shape, and the length of the plurality of thin tubes is set to be the same.
In addition to being set within the range of 100 mm to 3000 mm,
It is characterized in that the inner diameters of the plurality of thin tubes are set within a range of 2 mm or more and 30 mm or less.

[Action]

In the above-described exhaust gas sample extracting device of the present invention, the exhaust gas discharged from the engine body is introduced into each thin tube of the proportional divider through the diffuser, and the exhaust gas sample is sampled by the sample probe of the thin tube. Taken out. At this time, the exhaust gas from the engine body is uniformly mixed by the straight pipe portion of the diffuser, and the respective thin pipes are set to have substantially the same length, inner diameter, and shape. It is evenly distributed to each thin tube.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.
1 and 2 show an exhaust gas sample extracting device as one embodiment of the present invention. FIG. 1 (a) is its side view, FIG. 1 (b) is its plan view, and FIG. c) is I in Fig. 1 (b)
FIG. 2 is a sectional view showing a modified example of the diffuser shape corresponding to FIG. 1 (c).

As shown in FIGS. 1 (a) to 1 (c), the exhaust gas sample extracting device of the present embodiment has a diffuser 1 whose one end is connected to an exhaust gas pipe 7 of an engine body 6 and the diffuser 1.
It has a proportional divider 2 whose one end is connected to the other end and a surge tank 5 into which the other end of the proportional divider 2 is introduced.

A flange portion 1a is provided at one end of the diffuser 1,
This flange portion 1a is connected to a flange portion 7a provided at an end portion of the exhaust gas pipe 7, and a flange portion 1b is provided at the other end of the diffuser 1 as well.
Is connected to a flange 8a provided on the case 8 of the proportional divider 2.

Further, the diffuser 1 has a reduced diameter pipe portion 9 having substantially the same diameter as the exhaust pipe 7 at one end thereof, and an enlarged diameter straight pipe portion 10 having a diameter larger than that of the reduced diameter pipe portion 9 at the other end side thereof, The reduced diameter pipe portion 9 and the expanded diameter straight pipe portion 10 are joined together by a horn-shaped pipe portion 11.

The diameter-expanded straight pipe portion 10 has a length L of approximately 10 times the inner diameter d.
It is set to double. This is a setting that allows the exhaust gas to be uniformly mixed in the process of passing through the radially expanded straight pipe portion 10 even if the radially expanded straight pipe portion 10 has a small diameter of, for example, d = 70 to 85 mm. is there. That is, when L is smaller than 10d, it becomes difficult to make the exhaust gas uniform, and on the other hand, the smaller L is, the more compact the device can be made.

The proportional divider 2 includes a plurality of thin tubes 3 and 4 inside the case 8, one end of which is opened to the other end of the diffuser 1.

All of these thin tubes 3 and 4 have the same size and shape, and bent portions 3a and 4a are provided in the middle portions. And
The lengths of the thin tubes 3 and 4 are set within the range of 100 mm to 3000 mm, and the inner diameters thereof are set within the range of 2 mm to 30 mm.

When the length of the thin tube is too large, the internal pressure becomes excessive. On the contrary, when the length of the thin tube is too small, the respective thin tubes 3 and 4 are set.
This is done because the pressure difference between the suction end 3c, 4c and the discharge end 3b, 4b cannot be kept constant.When setting the inner diameter too large, the pressure difference cannot be kept constant. If it is too small, the internal pressure will be too large.

Of these thin tubes 3 and 4, those with reference numeral 3 are arranged with the bent portions 3a facing both sides, and the other ends are introduced into the surge tank 5. The thin tube indicated by reference numeral 4 is configured as a sample probe, the bent portion 4a is directed upward, and the discharge end 4b at the other end is separated from the discharge end 3b of the thin tube 3 and shown in FIG. It is arranged so as to be introduced into the distribution pipe 42 similar to that of the conventional example shown in FIG.

The cross section of the diffuser 1 may be a circular cross section shown in FIG. 1 (c), a hexagonal cross section 1'as shown in FIG. 2, or another polygonal cross section.

In addition, the exhaust gas analyzer including the flow pipe 42,
It is configured similarly to the conventional example. That is, as shown in FIG. 3, a diffusion orifice 43 and a critical flow velocity venturi 44 are provided in the flow pipe 42, respectively, and
The suction blower 45 is connected to the venturi 44 side,
Air is sucked into the flow pipe 42 through the air filter 46 by the suction blower 45.

The discharge end 4b of the sample probe 4 is arranged closer to the air filter 46 than the diffusion orifice 43. And
A mixing chamber 47 for the exhaust gas discharged from the sample probe 4 and the air introduced via the air filter 46 is formed on the upstream side of the diffusion orifice 43 in the flow pipe 42. The mixed and diluted exhaust gas is passed through the diffusion orifice 43 to the venturi 4
It is designed to be leaked to the 4 side.

In addition, one end portion of an intake pipe 48 is inserted near the venturi 44 in the flow pipe 42. The other end of the intake pipe 48 is connected to an exhaust gas analyzer 50 via a bag 49.
The exhaust gas analyzer 50 is used to analyze the components of the exhaust gas.

The particulate collection filter holder 51, the constant sample flow rate controller and the gas analyzer 52 are also provided in the same manner as in the conventional example.

Since the exhaust gas sample extracting device of the present invention is configured as described above, the exhaust gas discharged from the engine body 6 is guided from the exhaust pipe 7 through the diffuser 1 into the proportional divider 2.

At this time, since the length L of the expanded straight pipe portion 10 of the diffuser 1 is set to about 10 times the diameter d, the expanded gas straight pipe portion 10 mixes the exhaust gas sufficiently and the proportional divider 2 Evenly distributed and guided to each thin tube 3, 4. Then, after the exhaust gas passes through the thin tubes 3 and 4 set to the same shape and the same size under the same conditions, the exhaust gas in the thin tube 4 is introduced into the flow pipe 42, and the exhaust gas in the thin tube 3 is removed. Guided into the surge tank 5.

At this time, the surge tank 5 also holds the exhaust gas from each thin tube 3 in the same outflow state as the exhaust gas guided from the thin tube 4 into the distribution tube 42.

Further, since the lengths of the thin tubes 3 and 4 are set to 100 to 3000 mm and the inner diameters thereof are set to 2 to 30 mm, the exhaust gas pressure P ₁ at the suction ends 3c and 4c of the thin tubes 3 and 4 is Exhaust gas pressure P ₂ at the discharge ends 3b, 4b of the thin tubes 3, 4
The differential pressure ΔP (= P ₁ −P ₂ ) with respect to is secured within a desired range. For example, if the lengths and inner diameters of the thin tubes 3 and 4 are set to appropriate values within the above range, ΔP changes momentarily depending on the output state of the engine body 6, etc., but the maximum value of ΔP is from 100 mmHg to 300 mmHg. The size of the range becomes, and the gas analysis by the exhaust gas analyzer 50 becomes possible.

Therefore, the exhaust gas in an appropriate pressure state is guided from the thin tube 4 to the exhaust gas analysis system as in the conventional case, and the desired analysis is performed.

As described above, in the exhaust gas sample extracting device of the present embodiment, the exhaust gas can be evenly distributed to the thin tubes 3 and 4, and the exhaust gas can be distributed in the thin tubes 3 and 4 and the discharge ends 3b and 4b under the same conditions. Since the exhaust gas is distributed and discharged, extremely accurate exhaust gas sampling is realized. Then, the pressure of the exhaust gas is also given in an appropriate range, and the analysis can be reliably performed.

The surge tank 5 may be omitted if the discharge end 3b of the thin tube 3 releases to the atmosphere.

Although the inner diameters d of the thin tubes 3 and 4 are substantially constant, the value of each d is determined so that the cross-sectional area within the tubes is within ± 20% of the reference cross-sectional size.

[Effect of device]

As described above in detail, according to the exhaust gas sample extraction device of the present invention, the exhaust gas is evenly distributed from the diffuser to each thin tube, and the exhaust gas is sampled in a desired pressure state. With a small analyzer, exhaust gas analysis of a large engine can be performed with extremely high precision as a large analyzer. Therefore, the small analyzer can be sufficiently applied to the exhaust gas analysis of the large engine, which contributes to the reduction of the analysis cost.

[Brief description of drawings]

1 and 2 show an exhaust gas sample extracting device as one embodiment of the present invention. FIG. 1 (a) is its side view, FIG. 1 (b) is its plan view, and FIG. c)) is shown in Fig. 1 (b).
Ic-Ic arrow sectional view, FIG. 2 is a sectional view showing a modified example of the diffuser shape corresponding to FIG. 1 (c), and FIG.
9 shows a conventional exhaust gas sample extracting device, FIG. 3 is a schematic configuration diagram of the entire exhaust gas analyzer equipped with the same device, FIG. 4 is a side view showing the exhaust diffuser, and FIG. Is a front view thereof, FIG. 6 is a perspective view thereof, and FIG.
The drawing is a side view showing the proportional divider partially broken, FIG. 8 is a front view showing the discharge port of the proportional divider, and FIG. 9 is a plan view showing the proportional divider partially broken. 1, 1 '... Diffuser, 1a, 1b ... Flange part, 2
...... Proportional divider, 2b …… Discharge end, 2c …… Suction end, 3 ……
Capillary, 3a ... Bent, 3b ... Discharge end, 3c ... Suction end, 4
...... Capillary tube as sample probe, 4a ...... Bent part, 4b
...... Discharge end, 4c ...... Suction end, 5 ...... Surge tank, 6 ...
… Engine body, 7 …… Exhaust pipe, 7a …… Flange part, 8
...... Case, 8a ...... Flange part, 9 ...... Reducing tube part, 10
...... Expansion straight pipe part, 11 ...... Horn type pipe part, 42 ...... Flow pipe, 43 ...... Orifice, 44 ...... Venturi, 45 ...
... Suction blower, 46 ... Air filter, 47 ... Mixing chamber, 48 ... Intake pipe, 49 ... Bag, 50 ... Exhaust gas analyzer, 51 ... Particulate collection filter holder, 52 ... Constant sample Flow controller and gas analyzer.

Claims (1)

[Scope of utility model registration request] 1. A proportional divider for uniformly dividing the exhaust gas in the exhaust passage, comprising a plurality of thin tubes arranged in an intermediate portion of an exhaust passage through which exhaust gas from the engine body flows. A diffuser for evenly guiding the exhaust gas to each thin tube of the vessel, a sample probe is formed by any of the thin tubes, and the sample probe forms an exhaust gas sample proportional to the flow rate of the exhaust gas in the exhaust passage. In the exhaust gas sample extraction device capable of taking out, the diffuser is provided with a straight pipe portion, and the plurality of thin tubes are set to have substantially the same length and inner diameter and shape, respectively, and the length of the plurality of thin tubes is set to be the same. In addition to being set within the range of 100 mm or more and 3000 mm or less, the inner diameter of the plurality of thin tubes is set within the range of 2 mm or more and 30 mm or less Characterized Rukoto, exhaust gas sample extraction device.