JP2910680B2 - Exhaust gas measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas measuring device for determining the weight of exhaust gas discharged from an engine.

[0002]

2. Description of the Related Art In an automobile, an exhaust gas measuring device is used.
2. Description of the Related Art In an exhaust gas test mode including acceleration and deceleration, the weight of exhaust gas emitted from an engine is measured and evaluated.

[0003] The exhaust gas measuring apparatus includes a Japanese Utility Model Laid-Open No. 4-116.
As disclosed in Japanese Unexamined Patent Application Publication No. 620, a sampling device is used to collect exhaust gas diluted with atmospheric air.

In many cases, exhaust gas from an engine is collected by using a sampling device employing a method called CVS (Constant Volume Sampler).

More specifically, as shown in FIG. 4, a sampling device a comprises a passage d open to the atmosphere in which a venturi b and a filter c are interposed, and a blower e for introducing atmospheric air into the passage d. And a passage h for introducing exhaust gas from a test vehicle (vehicle) g operating on the chassis dynamometer f in a predetermined exhaust gas test mode into the passage d. The suction force of the blower e causes the passage d to have a constant flow rate. The exhaust gas emitted from the engine is mixed with the air flowing through the engine.

Exhaust gas is collected from between the passage h and the venturi b via a sampling venturi i, a passage j, and a pump (not shown).
Collected in a bag (not shown).

At this time, the air in the atmosphere is also separated from the other passages k,
Bag (not shown) through pump (not shown)
Collected in. HC, C contained in air collected from diluted exhaust gas collected by an analyzer (not shown)
O, obtaining a net exhaust gas concentration by subtracting regulating substance (impurity) such as NO _X.

Then, by calculating the net exhaust gas concentration and the flow rate coefficient of the venturi b, the diluted exhaust gas amount in the standard state obtained by measuring the inlet temperature and the inlet pressure of the venturi b, the test vehicle g The weight of the discharged exhaust gas is measured.

In such a measurement, the exhaust gas emission weight can be measured with high accuracy. However, it has become necessary to further improve this accuracy. This is because the air pollution caused by automobiles has become more serious year by year, and the emission regulations have been gradually tightened in each country. In recent years, strict regulations have been enacted to reduce harmful emissions to zero.

[0010] Therefore, by receiving the perform measurement by supplying the sampling device of conventional as atmospheric air, as described above directly as dilution air, HC in the atmosphere, CO, the effect of impurities such as NO _X, The inconvenience that high measurement accuracy cannot be secured has arisen.

As a countermeasure, it has been proposed to connect an air purifier n to a dilution air inlet m of a sampling device a as shown in FIG. That is, the air purifier n
Is gas control device p, be configured with a blower fan q, HC of the air taken in from the atmosphere by the blower fan q, CO, dilution air purified by removing the NO _X purifying impurities such equipment n Has the function of creating

For this reason, the exhaust gas measuring device can provide high exhaust gas measuring accuracy by supplying the purified dilution air to the sampling device a instead of the air in the atmosphere.

[0013] However, since the exhaust gas regulation concentration, that is, the measured concentration, is greatly different between a country where exhaust gas regulations are strict and other countries, the use of this air purifier for all exhaust gas tests requires the durability of the air purifier itself. It is not preferable in consideration of the properties and the deterioration of the catalyst and the like provided in the air purifier, that is, the replacement time. For this reason, in countries where exhaust gas regulations are strict, exhaust gas measurement using diluted air purified by an air purifier is performed, and in other countries exhaust gas that simply uses air in the air that flows in through a filter as dilution air is used as in the past. It is desirable to measure. However, separately preparing exhaust gas measuring devices in accordance with the exhaust gas measuring concentration increases the cost of the measuring device, and also increases the size of the measuring device and requires a wide installation space. .

An object of the present invention is to provide an inexpensive exhaust gas measuring apparatus capable of reducing the size of the measuring apparatus, setting the installation space small, and inexpensive. It is in.

A second object of the present invention is to provide an inexpensive and easy-to-use exhaust gas measuring device for switching between purified air and atmospheric air as dilution air for a CVS sampling device.

[0016]

According to a first aspect of the present invention, there is provided an exhaust gas measuring apparatus comprising: an air purifier for purifying dilution air by taking in air in the atmosphere; and air in the atmosphere as dilution air separately from the air purifier. An air introduction device for taking in air, a first passage for flowing the first dilution air purified by the air purifier, a second passage for flowing the second dilution air introduced from the introduction device, and the first dilution. Selecting means for selecting one of the air and the second dilution air and guiding it downstream; a sampling device for collecting an exhaust gas of the engine diluted by the one dilution air selected by the selection means; Measuring means for obtaining the exhaust gas emission weight of the exhaust gas.

[0017] The exhaust gas measuring apparatus according to claim 2 is characterized in that the air purifier purifies the air using a catalyst and an adsorbent. The exhaust gas measuring device according to claim 3 is:
Either the first passage or the second passage is connected to the other,
The other passage is connected to a sampling device.

According to a fourth aspect of the present invention, in the exhaust gas measuring device, the selecting means has a first valve provided in the first passage and a second valve provided in the second passage. , The dilution air introduced into the sampling device is selected.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on one embodiment shown in FIGS. FIG. 1 shows an overall schematic configuration of an exhaust gas measuring apparatus to which the present invention is applied. In FIG. 1, reference numeral 1 denotes an air purifier installed in a machine room of a building, for example.

The main body 1a of the air purifier 1 has an air inlet 2 and an air outlet 3 open to the atmosphere. In the main body 1a, a suction fan 4 having a variable blowing capacity for taking in air in the atmosphere from the inlet 2 and sending the air to the air outlet 3 is provided.
And HC, CO, NO contained in the air taken in
A purification device 5 for removing impurities such as _X is provided.

The air outlet 3 is connected via a connection duct 6 to a main duct 7 (corresponding to a main passage) arranged, for example, along the ceiling of the first floor of the building. The main duct 7 is connected to sampling devices 11 and 11a for each test bench installed on the floor of the first floor, which will be described later, and the air purified by the air purifier 1 is passed through the main duct 7 to each sampling device 11a. , 11a.

Incidentally, for example, one end of the main duct 7 is closed by a removable blind lid 8, and the main duct 7 is closed.
Can be extended. Further, the air purifier 1 has a controller 1b (comprising a microcomputer and its peripheral circuits, corresponding to a flow control unit) for blowing purified air having an appropriate flow rate according to the number of operating sampling devices 11 and 11a. Is provided.

That is, the controller 1 b is connected to the blower fan 4. Further, the controller 1b is also connected to a sensor 7b for detecting the sensor 7a and the atmospheric pressure P ₂ for detecting the pressure P ₁ in the main duct 7.

The controller 1b is provided with a function of controlling the number of revolutions of the suction fan 4 so that the difference ΔP between the pressures P ₁ and P ₂ is substantially constant so that the required supply air volume is always secured. .

With this function, the necessary dilution air amount is automatically adjusted according to the number of operating units, and can be sent to the main header 7. On the other hand, for example, on the floor of the first floor,
A plurality of test benches, for example, two sets of test benches A and B, a first test bench and a second test bench, are provided.

These first and second test benches A and B are:
Both have the same structure. FIG. 2 shows the structure around one of the test benches A, for example.

Here, the structure around the test bench A will be described. Reference numeral 9 denotes a chassis dynamometer for operating the test vehicle 10 (corresponding to an automobile) with the vehicle body stationary.

In the vicinity of the chassis dynamometer 9,
A sampling device 11 is installed. The sampling device 11 employs, for example, a CVS (Constant Volume Sampler).

To explain the sampling device 11, the main body 12 of the sampling device 11 has an inlet 13 for taking in dilution air and an outlet 14 for opening to the atmosphere.

The intake 13 is connected to a branch duct 15 (corresponding to a branch passage) as a first passage branched from the main duct 7 for each sampling device, and the air purified by the air purifier 1 is used as dilution air. , It can be taken.

A passage 16 (corresponding to a first passage portion) is provided in the main body 12 so as to communicate between the inlet 13 and the outlet 14. In the passage 16, a mixing section 18 and a cyclone 19 for removing dust are arranged in this order from the upstream side. Further, a turbo blower 20 (corresponding to a suction device) for suctioning to the downstream side is provided downstream of the passage 16 so that dilution air is sucked from the intake 13.

From the mixing section 18, a connecting pipe 23 (second pipe) which is detachably connected to an exhaust pipe 21 of the test vehicle 10 (which discharges exhaust gas from an engine 22 mounted on the test vehicle 10 to the atmosphere). A passage portion is extended, and the exhaust gas discharged from the engine 22 is diluted by mixing with the dilution air flowing through the passage 16.

A venturi section 24 for setting an appropriate dilution ratio is provided in a passage portion between the turbo blower 20 and the cyclone 19, which is on the upstream side of the turbo blower 19.

Specifically, the venturi section 24 includes a venturi reset section 25 provided in the same section, and a plurality of types of venturis detachable from the venturi reset section 25, for example, large venturis 26, which are separated from a specific flow rate performance. It has three types of venturis, a middle venturi 27 and a small venturi 28.

Here, the turbo blower 20 has a suction force for maintaining a sufficient critical flow regardless of which venturi 26 to 28 is selected.
Is selected, the mixed gas (mixture of exhaust gas and dilution air) flows through the passage 16 at a constant flow rate determined by the selected venturi.

That is, the required supply amount of dilution air is adjusted by setting the venturi reset unit 25 to a venturi selected from the large / medium / small venturis 26 to 28.

Thus, an appropriate dilution rate is selected by properly using the three types of venturis 26 to 28 according to the exhaust gas test mode and the size of the engine 22 (test conditions).

A measuring system 40 for measuring the amount of diluted exhaust gas is provided on the upstream side of the venturi reset section 25 which maintains a constant flow rate. The measurement system 40 includes, for example, a sensor unit 41 that measures the inlet temperature and pressure of the venturi, an arithmetic unit 42 that calculates the diluted exhaust gas amount in the standard state based on the information on the temperature and pressure, the flow coefficient of the venturi, and the time.
It has a flow rate display section 43 for displaying the calculation result.

In this way, the amount of diluted exhaust gas required for obtaining the exhaust gas discharge weight is obtained. Further, a collecting unit 30 is provided on the upstream side of the venture reset unit 25.

The collection unit 30 receives a suction force of a suction pump 31 disposed outside the passage, and causes a sampling venturi 32 disposed on the upstream side of the venturi reset unit 25 to receive a signal from a sampling venturi 32.
A structure is employed in which diluted exhaust gas (mixed gas of exhaust gas and dilution air) is collected at a constant flow rate and stored in the bag 33.

With this collecting structure, the diluted exhaust gas is stored in the bag 33 during the exhaust gas test mode, so that information on the average concentration of the exhaust gas during the exhaust gas test mode can be obtained.

Immediately upstream of the mixing unit 18, only the dilution air is collected by a suction pump 34 through a passage 38 and stored in a bag 35.
6 are provided.

During the exhaust gas test mode, the collection unit 36 allows the HC, C remaining in the purified air (dilution air) to remain.
Restricted substances (impurities) such as O and NO _X are stored.

The gas in these bags 33 and 35 is supplied to an analyzer 37 (which constitutes a measuring means together with the measuring system 40).
And the net exhaust gas concentration is determined.

Specifically, the analyzer 37 converts, for example, HC, CO, and NO _X contained in the purified air collected by the bag 35 from the diluted exhaust gas collected by the bag 33.
It has a function of calculating the net exhaust gas concentration by subtracting regulated substances (impurities) such as the above, and a function of calculating the net exhaust gas concentration and the diluted exhaust gas amount in the standard state to obtain the exhaust gas emission weight.

As a result, the weight of the exhaust gas discharged from the test vehicle 10 is determined. On the other hand, as shown in FIG. 1, a duct 44 (corresponding to a passage for taking in air in the atmosphere) as a second passage extending toward the machine room is connected to the outlet side of the branch duct 15.

The distal end of the duct 44 is connected to, for example, an air intake unit (atmosphere introduction device) 45 with a built-in filter installed above the room. Further, the duct 44 and the branch duct 15 are provided with a valve device for opening and closing the inside of the duct as a selecting means, for example, a motor-driven first valve 4.
6, a second valve 47 (corresponding to a switching valve device or a valve device) is provided.

The sampling device 11 operates such that the purified air from the air purifier 1 or the air in the atmosphere is selectively supplied as dilution air by the first valves 46 and 47, and furthermore, the flow rate according to the dilution rate. The operation in which purified air is supplied can be performed.

That is, each of the first valves 46 and 47 is, for example, a controller 48 provided for each sampling device 11.
(For example, a microcomputer and its peripheral devices).

Operation unit 4 connected to each controller 48
Reference numeral 9 denotes various operation buttons, for example, the sampling device 1
Power button to turn on / off the operation of 1, the button to set the exhaust gas test mode using air in the atmosphere as dilution air, the button to set the exhaust gas test mode to use purified air as dilution air, which venturi was used And a venturi selection button unit (not shown) for inputting a password.

The following functions are set in the controller 48. When the power button is turned off,
While the operation of the sampling device 11 is stopped,
A function of driving the valve 46 and the second valve 47 to be fully closed.

When the button in the exhaust gas test mode using the air in the atmosphere as dilution air is turned on, the first valve 46 is fully opened and the second valve 47 is fully closed. When the button in the exhaust gas test mode using purified air as dilution air is turned on, the first valve 46 is fully closed, and the second valve 47 is switched to the large / medium / small venturis 26 to 28 selected by the venturi selection button. Therefore, the function to drive fully open, half open and small open.

Function of operating the sampling device 11 in accordance with the exhaust gas test mode when the power button is turned on. With such a function, the air purifier 1 can be used for one sampling device simply by operating the operation unit 49.
Purified air from the air or air in the atmosphere is used as dilution air, or a fixed amount of purified air corresponding to the large / medium / small venturi 26-27 is taken in from the air purifier 1 to measure exhaust gas. Multiple tests can be performed according to the concentration.

Such a structure is also employed in the second test bench B, and a plurality of, in this case, two sampling devices 1 are used in one air purifier 1 which is the minimum number required.
Necessary purified air can be supplied to 1, 11a.

The information output from the operation buttons of the operation unit 49 is the same as the operation unit 49 output from the operation unit (not shown) of the sampling device or the automatic measurement device (not shown). May be connected.

The air purifier 1 has a capability of purifying a required maximum amount of dilution air of a plurality of sampling devices and sending the air in advance. In FIG. 1,
In order to distinguish between the first test bench A and the second test bench B, each part around the second test bench B is numbered with “a” at the end.

Next, the air purifier will be described in detail with reference to FIG. In FIG. 3, a pipe 51 connected to the intake 2 is connected to the suction fan 4. The air in the atmosphere is sucked by the suction fan 4. The downstream side of the suction fan 52 is connected to an electric heater 54 and a catalyst 55 via a U-shaped pipe 53. This electric heater 54
Has a function of warming the air sucked by the suction fan 52 to about 400 ° C.

The catalyst 55 is an oxidation catalyst,
CO is completely burned to produce CO ₂ . Since the electric heater 54 is also for activating the catalyst, it is placed upstream of the catalyst 55.

An L-shaped pipe 5 is provided downstream of the catalyst 55.
6 and connected to a cooler 57. The cooler 57 cools the air. The downstream side of the cooler 57 is connected to an activated carbon adsorption layer 59 via a pipe 58. The activated carbon adsorption layer 59 removes NO.

The air that has passed through the activated carbon adsorption layer 59 is connected to the connection duct 6. Next, the operation of the exhaust gas measuring device thus configured will be described. First, for example, when the measured exhaust gas concentration is not severe (the measured concentration level is high), control is performed to open the first valve 46 and close the second valve 47. For this reason, the air taken in from the air intake body 45 is passed through the built-in filter, and then guided to the sampling device 11 via the first valve 46.

On the other hand, when the measured exhaust gas concentration is severe (the measured concentration level is low), the first valve 46 is closed and the second valve 46 is closed.
The control for opening the valve 47 is performed. For this reason, the air taken in from the inlet 2 is sucked in by the rotational suction force of the suction fan 4, heated to about 400 ° C. by the electric heater 54, and then oxidized by the oxidation catalyst 55 (catalyst). HC and CO are completely burned by the oxidation catalyst 55 to form CO ₂ . The oxidation catalyst 55 is activated by the electric heater 54.

After the air that has passed through the oxidation catalyst 55 is cooled by the cooler 57, NO is removed by the activated carbon adsorption layer 59 (adsorbent). As described above, the oxidation catalyst 55 and the activated carbon adsorption layer 59 in the air purifier 1 are made to act only during the test when the exhaust gas measurement concentration is severe. And the life of the oxidation catalyst 55 and the activated carbon adsorption layer 59 can be prolonged.

The diluted air thus obtained is supplied to the main duct 7, the branch duct 15, and the second valve 47.
And is introduced into the sampling device 11 via. In the sampling device 11, dilution air is taken in via a branch duct 15. Here, the sampling device 1
1, the filter c as shown in FIG.
This is because the dilution air obtained from the air purifier 1 and the air introduced from the air intake body 45 pass through the same filter, and the dilution air purified by the air purifier 1 Prevents contamination with impurities.

Here, for example, using both the first test bench A and the second test bench B, and using purified air as dilution air, the exhaust gas emission weight of each test vehicle 10, 10a in the exhaust gas test mode is measured. It shall be.

As a preparation for this, for example, the first test bench A is a test vehicle 1 mounted on the chassis dynamometer 9.
The connection pipe 23 is connected to the exhaust pipe 21 of No. 0 in advance. In addition, the exhaust gas test mode and the size of the engine 22 of the test vehicle 10 (test conditions) are selected from among the three venturis 26 to 28 so that an appropriate dilution ratio (the amount of exhaust gas discharged from the test vehicle 10 and the dilution air) is obtained. According to the appropriate venturi,
For example, a small venturi 28 is selected and set in the venturi section 24. In this selection, consideration is made so that the water in the exhaust gas does not condense and the measurement accuracy does not decrease (the measured exhaust gas concentration does not become too low).

The setting of the small venturi 28 determines the required supply amount of dilution air for the sampling device 11.
Similarly, for example, the second test bench B also connects the connection pipe 23a to the exhaust pipe 21a of the test vehicle 10a mounted on the chassis dynamometer 9a, and sets a proper dilution ratio (exhaust gas discharged from the test vehicle 10a). An appropriate venturi is selected from the three venturis 26 to 28 so that the volume and the dilution air), and this is set in the venturi portion of the sampling device 11a.

Next, the operation unit 49 for each test bench,
Operate 49a. This is performed by inputting the type of the venturi selected by the venturi selection button, turning on the button in the exhaust gas test mode using purified air as dilution air, and turning on the power button.

In response to this operation, the purified air ventilation system is set, and the air purifier 1, the sampling devices 11, 11
The test is started after a is activated and the catalyst 55 is activated.
The catalyst in the air purifier is activated (when the catalyst temperature is about 40
0 ° C.) until the catalyst is activated by switching the first valve 46 and the second valve 47 until the catalyst is activated. This makes it possible to perform a test using the air as dilution air, thereby improving the test efficiency.

In this embodiment, a plurality of sampling devices 1 are provided by the main duct 7 so that a plurality of tests can be performed.
1, 11a are connected, but the present invention is not limited to this embodiment, and the air purifier 1 and the air intake body 45 are connected to a single sampling device, and It goes without saying that it may be configured as a test device.

In this embodiment, the branch duct 15 is connected to the duct 44 and the first valve 4 is connected to each of the ducts 44 and 15.
6 and the second valve 47 are provided, but the respective ducts 44 and 15 are directly connected to the inside of the air purifier 1 so that valves such as the first valve 46 and the second valve 47 are provided inside the air purifier. An apparatus may be provided to switch between a duct from the air intake body 45 and a duct through which air purified by the air purifier passes. In the present embodiment, the first valve 46 and the second valve 46 are respectively connected to the duct 44 and the branch duct 15.
Although the configuration provided with the valve 47 is not particularly limited to this configuration, in order to simplify the configuration, when the measured concentration is high in accordance with the exhaust gas measured concentration at the connection between the duct 44 and the branch duct 15. Alternatively, a butterfly type switching valve that closes the passage of the branch duct 15 (the duct 44 is open) and closes the duct 44 (the branch duct 15 is open) when the measured concentration is low may be used.

[0071]

According to the first aspect of the present invention, the dilution air of the air purifier and the air introducing device is selectively switched so that tests having different exhaust gas concentrations can be measured with a single sampling device. Therefore, the test equipment can be made inexpensive, and the size of the test equipment can be reduced, so that the equipment space can be reduced. In addition, it is possible to switch between purified air and air in the atmosphere as dilution air for the sampling device, and to operate the air purifier only during tests with low exhaust gas measurement concentrations, so that the time during which the air purifier is used can be reduced. It can be shortened to extend its life, and the running cost as an exhaust gas measuring device can be eliminated. Further, in the air purifier having the structure in which the suction fan 52 and the electric heater 54 are provided as in the present embodiment, the power consumption of the suction fan 52 and the electric heater 54 is suppressed, and the waste is reduced. Power consumption can be suppressed.

According to the second aspect of the present invention, in addition to the effects of the first aspect of the present invention, air purification with high purification efficiency can be performed, and the operation of the air purifier is performed only during a test in which the measured concentration of exhaust gas is low. By doing so, particularly the deterioration of the catalyst provided in the air purifier can be suppressed, so that the life of the catalyst can be extended and the running cost can be reduced.

According to the third aspect of the present invention, in addition to the effect of the first aspect, the structure of the passage for introducing dilution air into the sampling device can be simplified. In addition, there is an effect that a commercially available device can be used without having to change the structure of the intake 13 provided in the sampling device as in the present embodiment. According to the invention of claim 4, in addition to the effect of the invention of claim 1, switching between purified air and air in the atmosphere can be reliably performed with an inexpensive and simple configuration.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining an exhaust gas measurement device according to one embodiment of the present invention.

FIG. 2 is a view for explaining a structure around a sampling device of the exhaust gas measuring device.

FIG. 3 is a diagram showing a detailed structure of an air purifier used in the exhaust gas measuring device.

FIG. 4 is a diagram for explaining a conventional exhaust gas measurement device.

FIG. 5 is a diagram for explaining an exhaust gas measuring device in which an air purifier is connected to a sampling device to dilute exhaust gas in order to increase measurement accuracy.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Air refiner 1a, 48, 48a ... Controller 4 ... Blower fan 7 ... Main duct (main passage) 9, 9a ... Chassis dynamometer 10, 10a ... Test car 11, 11a ... Sampling device 15, 15a ... Branch duct ( (Branch passage) 16: passage (first passage portion) 17: mixin q portion 19: cyclone 20: suction blower (suction device) 23: connection pipe (first passage portion) 24: venturi portion 26-28: large venturi Medium venturi, small venturi 30 ... Sampling unit 31,34 ... Suction pump 32 ... Sampling venturi 33,35 ... Bag 37 ... Analyzer 42 ... Calculation unit 43 ... Flow rate display unit 44 ... Duct (passage) 46 ... First valve (switching) Valve device) 47 Second valve (valve device) 49, 49a Operating part 51, 53 Piping 52 Suction fan 54 ... Electric heater 55 ... Catalyst.

Claims (4)

(57) [Claims] 1. An air purifier that takes in atmospheric air to purify dilution air, an air introducing device that takes in atmospheric air as dilution air separately from the air purifier, and an air purifier that is purified by the air purifier. A first passage through which the first dilution air flows, a second passage through which the second dilution air introduced from the introduction device flows, and one of the first dilution air and the second dilution air. Means for collecting the exhaust gas of the engine diluted by one of the dilution air selected by the selecting means, and a measuring means for obtaining the exhaust gas emission weight of the collected exhaust gas. An exhaust gas measuring device characterized by the above-mentioned. 2. The exhaust gas measuring apparatus according to claim 1, wherein said air purifier purifies air using a catalyst and an adsorbent. 3. The exhaust gas measuring device according to claim 1, wherein one of the first passage and the second passage is connected to the other, and the other passage is connected to a sampling device. 4. The selection means has a first valve provided in the first passage and a second valve provided in the second passage, and is introduced into the sampling device by opening and closing each valve. The exhaust gas measuring apparatus according to claim 1, wherein the apparatus is configured to select dilution air.