JPH0620996Y2 - Exhaust gas sample extractor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an exhaust gas sample extracting device for analyzing exhaust gas of an engine.

(Prior Art) Conventionally widely used exhaust gas sampling devices for engines guide all the exhaust gas discharged from the engine into a distribution pipe called dilution tunnel for diluting exhaust gas. Mixed with diluted air, the diluted exhaust gas is introduced into the exhaust gas analyzer through a bag containing a fixed amount of gas, and the exhaust gas analyzer analyzes the components of the exhaust gas. Since the entire amount of engine exhaust gas is introduced into the distribution pipe, the overall size of the device becomes extremely large, and the flow rate of exhaust gas in the distribution pipe is always kept constant even if the engine speed changes. Therefore, there is a problem that exhaust gas cannot be analyzed according to the engine speed.

Therefore, the specification and drawings of Jpn. Pat. Appln.
The applicant of the present invention has proposed an exhaust gas sample extracting device that solves the above problems as disclosed in Japanese Patent Application Laid-Open No. 0-127420).

An outline of the exhaust gas sample extracting device will be described with reference to FIG. 5. Reference numeral 10 is a test engine whose exhaust gas components are investigated, 12 is an exhaust pipe of the engine, and 14 is an exhaust diffuser connected to the exhaust pipe 12. , 16 are exhaust gas splitting devices connected to the upstream opening ends, and a large number of pipes 18 having substantially the same flow path resistance are uniformly arranged inside thereof.
20 is a suction reducer arranged facing the downstream opening end of the dividing device, 22 is a suction blower connected to the suction reducer 20, and 24 is formed by one of the above-mentioned many pipes, that is, one of the dividing pipes 18. A sample probe whose upstream opening end is adjacent to the downstream opening end of the diffuser 12,
And upstream pipe 24a taken out to the outside through the outer wall of the dividing device 16 downstream opening end, the downstream opening end 24A is introduced into the dilution flow pipe 26, and the upstream opening end of the dilution flow pipe 26 The downstream pipe 24b taken out through the pipe wall and the upstream pipe 2
It is composed of an intermediate pipe 24c that airtightly connects the 4a and the downstream pipe 24b. 28 is a diffusion orifice arranged in the diluting flow pipe 26 in proximity to the downstream open end 24A of the sample probe 24, 35 is a suction blower with a constant blowing capacity for forcedly introducing the atmosphere, and 30 is an upstream of the diluting flow pipe 26. A filter for removing atmospheric dust attached to the open end, 32 is a suction blower connected to the downstream open end of the dilution flow pipe 26 via a heat exchanger 34, and 36 is close to the heat exchanger 34 for dilution. Intake pipe inserted into the flow pipe 26 for exhaust gas, 38 is an exhaust gas analyzer connected to the intake pipe 36 via a bag 40, 42 is a holder for a filter that collects particulates in the exhaust gas, and 44 is a constant A sample flow controller and a gas analyzer.

In this exhaust gas sampling device, the engine 10
From exhaust pipe 12 and exhaust diff user 14 to dividing device 16
The exhaust gas introduced into the pipe is introduced into the split tube 18 and the sample probe 24. Then, the exhaust gas discharged from the sample probe 24 passes through the diffusion orifice 28 and is mixed with the atmosphere from the suction blower 35 arranged upstream of the diluting flow pipe 26, and a part of the diluted exhaust gas. Is taken into the intake pipe 36 inserted in the dilution flow pipe 26 and sampled. Here, the pressure P ₂ at the downstream opening end of the dividing device 16 and the pressure P ₁ at the upstream portion of the diffusion orifice 28 in the diluting flow pipe 26, that is, the pressure P ₁ around the downstream opening end 24A of the sample probe 24 are set to be substantially equal. , And the pressure difference P ₂ −P
By making the value of ₁ smaller than the pressure difference with the inlet pressure P ₀ of the dividing device 16, the flow rate in each of the dividing tubes 18 and the sample probe 24 can be made equal. Therefore, the device can be downsized because only a small amount of exhaust gas needs to be taken out as compared with the conventional device, and the exhaust gas can be analyzed according to the change in the engine speed.

(Problems to be Solved by the Invention) As described above, theoretically, the pressure of the upstream portion of the orifice 28, that is, the discharge port pressure P ₁ of the sample probe 24 and the pressure P ₂ of the downstream opening end of the dividing device 16 are determined. If they coincide with each other, the exhaust gas can be accurately proportionally divided by the dividing device 16, but in actuality, the operation, that is, P
_There is no specific means for setting ₁ = P _2, and proportional division with low accuracy was performed.

An object of the present invention is to provide an exhaust gas sample extracting device that can analyze exhaust gas with high accuracy.

(Means for Solving Problems) In order to achieve the above object, the exhaust gas sample extracting device of the present invention uses a variable blower as a suction blower provided upstream of the diluting flow pipe to make the flow rate through the orifice variable. It is characterized in that a variable means and a controller for operating the variable blower and the variable means so as to equalize the pressure upstream of the orifice and the pressure downstream of the division are provided.

(Operation) According to the present invention, the variable blower and the variable means receive the signal from the controller and operate so that the pressure upstream of the orifice becomes equal to the pressure downstream of the dividing pipe.

Embodiment An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a partial cross-sectional schematic configuration diagram of an exhaust gas sample extracting device showing an embodiment of the present invention, in which the same functions and functions as those of the above-mentioned prior art are denoted by the same reference numerals, and description thereof Are omitted because they overlap. The main difference of the exhaust gas sample extraction device of this embodiment from that of the prior art is the suction blower.
35 is a so-called variable blower 65 with variable blowing capacity, variable means 90 for varying the flow rate of the orifice 50 is provided, and the pressure upstream of the orifice 50, that is, the pressure P ₁ around the sample probe discharge port 24A in this embodiment. And the variable blower 65 and the variable means 90 are operated so that the pressure P _{2 on} the downstream side of the exhaust gas dividing device 16 becomes equal. Here, the variable blower 65 is a well-known blower whose blowing ability is changed by receiving an electric signal, and adjusts the amount of air.

Further, the orifice 50 and the variable means 90 for varying the flow rate of the passage through the orifice 50 are constructed as shown in FIG. In the figure, the orifice 50 is configured by combining flat plates 1 and 2 having finger-shaped notches 1a and 2a at their ends so as to overlap each other. The notches 1a and 2a are arranged so as to face each other so that the connections of the notches do not become staggered, and the notch 1a and 2a can form an elongated hole 3 substantially at the center. This plate 1,2
The side end portions of are provided with protrusions 1b and 2b, respectively,
A left-hand thread is formed on the protrusion 1b, and a right-hand thread is formed on the protrusion 2b. A left-hand thread 5b is formed on the upper portion and a right-hand thread 5a is formed on the lower portion of each female screw portion formed on the protrusions 1b and 2b. The bearing 4 is pivotally supported, and the lower part thereof is directly connected to the reversible motor M. Here, the male screw 5, the bearing 4, and the motor M
Variable means 90 for varying the flow rate through orifice 50
Are configured.

On the other hand, as shown in FIG. 1, a pressure sensor S1 is provided upstream of the orifice 50, a pressure sensor S2 is provided downstream of the exhaust gas dividing device 16, and a pressure sensor S2 is provided between the heat exchanger 34 and the suction blower 32. S3 are arranged respectively, and a controller 60 for receiving the pressure signals from the sensors S1, 2, 3 is provided. The controller 60 is a well-known microcomputer, has a built-in ROM, RAM, arithmetic means, etc.
In response to the pressure signals from 1, 2, and 3, an operation signal is sent to the motor B of the variable blower 65 and the variable means 90 so that the pressure P ₁ upstream of the orifice and the pressure P ₂ downstream of the exhaust gas dividing device 16 become equal. It is what is sent.

Next, the operation of the exhaust gas sample extracting device configured as described above will be described.

First, the controller 60 receives pressure signals from the sensors S1, 2, and 3 and sets initial values. Then, at the sampling stage, the concentration, amount, etc. of the exhaust gas change, and the pressure of each sensor changes. Then the controller 60
Pressure P ₃ of the sensor S3 is the initial value in the manner, and the above-described variable blower 65 and the variable means such that P ₁ = P ₂
An actuation signal is sent to the 90 motor M. Here, for example, when the flow rate passing through the orifice 50 is reduced, a signal is sent to the motor M to rotate the male screw 5 to the right, and the flat plates 1 and 2 move in the direction of the arrow as shown in FIG. The elongated hole 3 becomes a circular hole, and the flow rate is reduced. On the other hand, on the contrary, when increasing the flow rate, the motor M is rotated to rotate the male screw 5 counterclockwise.
A signal is sent to the flat plates 1 and 2 to move in the direction opposite to the direction of the arrow, and the elongated hole 3 becomes a larger elongated hole to increase the flow rate.

The pressure is adjusted as described above, P ₁ = P ₂ , and the sensor
When the pressure P _{3 of} S3 reaches the initial value, the controller 60
Is finished and the analysis by the exhaust gas analyzer 38 is performed.

Since the exhaust gas sample extracting device of this embodiment is configured in this manner, the pressure P _{1 at} the upstream portion of the orifice 50 and the dividing device 1 are maintained while maintaining the pressure P _{3 of the} sensor S3 at the initial value.
The pressure P ₂ at the downstream opening end of 6 can be made to match, and the proportional division of the exhaust gas by the dividing device 16 can be performed accurately.

FIG. 3 is a front view showing another example of the orifice and the variable means used in the exhaust gas sample extracting device of the above. As shown in the figure, the orifice 51 is a long flat plate 6, 7, 8,
It is configured by alternately combining 9 on a mesh and a square opening 80 is formed by the side surfaces of the flat plates 6, 7, 8 and 9. Projections 6b, 7b, 8b, 9b are provided at the ends of the flat plates 6, 7, 8, 9 respectively, and the projections 7b, 8b are provided with a left-hand thread, and the projections 6b.9b are provided with the projections 6b, 9b. Right-hand threads are formed respectively. A right-hand thread 25b is formed on the upper part and a left-hand thread
5a is formed on the male screw 25, and each of the female screw portions formed on the projections 8b and 9b is screwed with the left screw 23b formed on the upper portion and the male screw 23 formed on the lower portion with the right screw 23a. The upper portions of the male screws 23, 25 are bearings 13, 15 respectively.
Is supported by and bevel gears 46 and 47 are connected to the lower part thereof. The bevel gears 46 and 47 mesh with each other, and a bevel gear 45 further meshes with the bevel gear 46, and the bevel gear 45 is directly connected to a reversible motor (not shown). Here, the male screws 23 and 25, the bearings 13 and 15, the bevel gears 45, 46 and 47, and the reversible motor constitute variable means 91 for varying the flow rate through the orifice 51.

It is needless to say that even with such a configuration, the same effects as in the case where the orifice 50 and the variable means 90 for varying the flow rate of the passage of the orifice 50 are used are exhibited. That is, for example, when the flow rate passing through the orifice 51 is reduced, a signal is sent from the controller 60 to the reversible motor to rotate the bevel gear 45 to the right, and the flat plates 6, 7, 8 and 9 are moved as shown in FIG. When moving in the direction of the arrow, the square hole 80 becomes smaller and the flow rate is reduced, while on the other hand, when increasing the passing flow rate, a signal is sent to the reversible motor to rotate the bevel gear 45 counterclockwise, and the flat plate 6, 7, 8 and 9 move in the direction opposite to the direction of the arrow, and the square hole 80 becomes a large hole to increase the flow rate.

FIG. 4 is a side sectional view showing still another example of the orifice and the variable means used in the above-mentioned exhaust gas sample extracting device. As shown in the figure, the orifice 28 is a fixed type orifice similar to that used in the prior art.
On the other hand, in the orifice, the downstream tube 24b of the sample probe 24 is inserted, a screw 74 is formed at the tip thereof, and a piece 71 for varying the flow rate of the orifice is screwed into the screw 74. There is. A ring gear 75 is fixed to the outer periphery of the piece 71, and a worm gear 76 meshes with the ring gear 75. The worm gear 76 is directly connected to a reversible motor (not shown). On the other hand, a conical hole 73 is formed inside the piece 71, and a conical cone 72 made of an elastic piece is fitted in the hole 73. This conical cone 72 has a fan shape when unfolded, and has a habit of opening outward by being rolled into a hole 73 and inserted. here,
The piece 71, the conical cone 72, the conical hole 73, the screw 74, the ring gear 75, the worm gear 76, and a reversible motor constitute variable means 92 for varying the flow rate through the orifice 28.

It goes without saying that even if configured in this way, the same effects as in the case of using the above-mentioned variable means 90 for varying the flow rate of the orifice 50 and the orifice 50 can be exerted.
For example, if you want to reduce the flow rate through the orifice 28,
A signal is sent from the controller 60 to the reversible motor to move 71 to the left in the figure, while a signal is sent from the controller 60 to the reversible motor to move the piece 71 to the right in the figure when increasing the flow rate through the orifice 28. Is sent. By adjusting the flow rate in this way, the pressure P _{1 at} the upstream portion of the orifice 28 and the pressure P ₂ at the downstream opening end of the dividing device 16 are made to match while maintaining the pressure P _{3 of the} sensor S3 at the initial value. Like

Furthermore, the orifice is a well-known camera shutter,
A motor may be attached as an operating mechanism of the camera shutter, that is, a flow rate changing mechanism, and the controller 60 may operate the motor.

The position of the variable blower 65 in the above embodiment is upstream of the filter 30, but it may be between the filter 30 and the orifice.

The pressure adjustment in the above embodiment (flow adjustment) is being performed by the variable means for the flow rate through the variable blower 65 and the orifice in the variable, only the variable means and P ₃ = initial value and P ₁ = P ₂ If possible, the flow rate may be adjusted only by the variable means.

(Effect of the Invention) As described above, according to the present invention, the suction blower provided upstream of the diluting flow pipe is a variable blower, and the variable means for varying the flow rate of the orifice is provided, and the pressure upstream of the orifice and the dividing pipe Since the variable blower and the variable means are operated so that the downstream pressure becomes equal, the exhaust gas can be accurately proportionally divided, and the exhaust gas sample extracting device with excellent analysis accuracy can be obtained.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional schematic configuration diagram of an exhaust gas sample extracting device showing an embodiment of the present invention, FIG. 2 is a front view of an orifice and a variable means used in the same device, and FIG. 3 is used in the same device. FIG. 4 is a front view showing another example of the orifice and the variable means, FIG. 4 is a side sectional view showing still another example of the orifice and the variable means used in the same apparatus, and FIG. It is a partial cross-section schematic block diagram of an apparatus. 10 …… Engine, 12 …… Exhaust pipe, 14 …… Exhaust diffuser, 16 …… Exhaust gas divider, 18 …… Split pipe, 24 …… Sample probe, 24A …… Sample probe outlet, 26
...... Dilution flow pipe, 28,50,51 …… Orifice, 35 …… Suction blower, 38 …… Exhaust gas analyzer, 60 …… Controller, 65 …… Variable blower, 90,91,92 …… Variable means , P ₁ ...
… Pressure upstream of the orifice, P ₂ … Pressure downstream of the dividing pipe.

Claims (1)

[Scope of utility model registration request] 1. An exhaust gas passage discharged from an engine is provided with a dividing pipe for dividing the exhaust gas into a plurality of substantially equal flows, and a sample probe is formed by any one of the dividing pipes. A small amount of the exhaust gas sample proportional to the flow rate of the exhaust gas in the exhaust gas passage is guided to the dilution flow pipe by the probe, and the exhaust gas is passed through an orifice arranged downstream of the sample probe discharge port to dilute the sample. In an exhaust gas sample extraction device that mixes with the atmosphere forcedly introduced by a suction blower from the upstream of the flow pipe and samples the diluted exhaust gas, the suction blower is a variable blower and the flow rate through the orifice is variable. The variable blower and the variable blower for equalizing the pressure upstream of the orifice and the pressure downstream of the dividing pipe. Exhaust gas sample extraction apparatus characterized by comprising a controller for actuating the serial varying means.