WO2013001663A1

WO2013001663A1 - Device for evaluating catalytic performance in purifying exhaust gas

Info

Publication number: WO2013001663A1
Application number: PCT/JP2011/073111
Authority: WO
Inventors: 明豊高宮; 幸太郎高橋
Original assignee: 株式会社ベスト測器
Priority date: 2011-06-30
Filing date: 2011-10-06
Publication date: 2013-01-03
Also published as: JP2013011238A; JP4813626B1

Abstract

Provided is a gas-introduction pipe (1), a gas cell (2), an infrared heater (4), coolers (6a, 6b) for cooling a region extending over a given length to the gas-introduction pipe side from the gas cell side, and a light-blocking plate (12) extending to the downstream side of the cooled region. An exhaust-gas purification catalyst (3) is accommodated in a region in which infrared rays are blocked, on the downstream side of the cooled region inside the gas cell. A temperature sensor (13) is arranged just before the exhaust-gas purification catalyst in the region in which the infrared rays inside the gas cell are blocked. A controller (14) controls the coolers according to a set value for a simulated exhaust-gas temperature for the position of the temperature sensor, and controls the infrared heater on the basis of a detection signal sent from the temperature sensor. Cooling is at all times performed by the cooler, and the cooling output from the cooler and the heating output from the infrared heater are controlled so that the temperature of the simulated exhaust gas immediately upstream of the exhaust-gas purification catalyst corresponds with the set value for the simulated exhaust-gas temperature.

Description

Exhaust gas purification catalyst performance evaluation device

The present invention relates to an apparatus for evaluating the performance of an exhaust gas purification catalyst provided in an exhaust system of an internal combustion engine such as an automobile.

In order to reduce air pollution caused by automobile exhaust gas, exhaust gas regulations have been implemented mainly in Japan, the United States and Europe, and this exhaust gas regulation tends to be strengthened in stages. Automobile exhaust gas regulations are discharged from the internal combustion engine of a motor vehicle, nitrogen oxides _(NO X), carbon monoxide (CO), hydrocarbons (HC), non-methane hydrocarbons (NMHC), particulate matter (PM) Regulations stipulating the upper limit amount of air pollutants, etc., and if this regulation is not cleared, measures such as refusing new car registration are taken.

In automobile exhaust gas regulations, test modes are defined, and for example, test modes such as JC08C mode and JC08H mode in Japan and LA4 mode in the United States are well known.
In the exhaust gas measurement test, the vehicle is set on the chassis dynamometer and traveled in the specified test mode, and the amount of air pollutants in the exhaust gas during the test period is determined by the specified measurement method. It is executed by measuring on the basis of.

In addition, the exhaust system of an automobile internal combustion engine is equipped with an exhaust gas purification device equipped with an exhaust gas purification catalyst. In order to clear exhaust gas regulations that are tightened year by year, it is essential to improve the performance of the exhaust gas purification catalyst. For this reason, research and development of exhaust gas purification catalysts are actively conducted.

An exhaust gas purification catalyst performance evaluation device is used for research and development of exhaust gas purification catalysts. In the exhaust gas purification catalyst performance evaluation apparatus, a simulated exhaust gas containing the same components as the exhaust gas from the internal combustion engine is usually used. The simulated exhaust gas is a mixture of various components contained in the exhaust gas of the internal combustion engine, such as NO _X , CO ₂ , HC, H ₂ O, etc., with nitrogen gas so as to have a concentration similar to the concentration in the exhaust gas. It is.

The simulated exhaust gas is brought into a temperature state similar to the exhaust gas immediately before the catalyst in the exhaust gas purification device of the vehicle while traveling in the test mode, and is introduced into the gas cell containing the catalyst, and before and after the catalyst. The performance of the catalyst is evaluated by measuring the gas concentration.

In this case, in order to improve the accuracy of performance evaluation, the temperature of the simulated exhaust gas immediately before the catalyst in the gas cell can be changed to the temperature change of the exhaust gas immediately before the catalyst in the exhaust gas purification device of the vehicle running in the test mode as much as possible. It is important to change it so that it can be accurately reproduced. To do so, it is necessary to raise and lower the temperature of the simulated exhaust gas immediately before the catalyst in the gas cell at high speed, in other words, the simulation just before the catalyst. The temperature gradient when raising and lowering the temperature of exhaust gas must be increased.

As a conventional catalyst performance evaluation apparatus that achieves this, for example, a first heating unit and a second heating unit are sequentially provided along a gas cell in which simulated exhaust gas supplied from a simulated exhaust gas supply path flows, and the simulated exhaust gas is provided by the first heating unit. The catalyst disposed in the gas cell is heated by the second heating unit, the branch channel is connected to the simulated exhaust gas supply channel, and the downstream end of the branch channel is connected to the first heating unit and the second heating unit. Connected to the gas cell, and provided with flow control valves that adjust the flow rate of the simulated exhaust gas in each of the simulated exhaust gas supply channel and the branch flow channel, detect the temperature near the catalyst inlet, and adjust the flow rate based on the detected value There is known a catalyst performance evaluation apparatus that adjusts the opening of a valve so that the temperature in the vicinity of the catalyst inlet becomes a predetermined temperature (see, for example, Patent Document 1).

In this apparatus, each of the first and second heating units is controlled so as to always be on and generate a predetermined amount of heat. Also, simulated exhaust gas at room temperature is supplied to the simulated exhaust gas supply path, and is divided into a hot line (simulated exhaust gas supply path after the branch point) and a cool line (branch path) at the branch point. Then, the simulated exhaust gas flowing through the hot line is supplied into the gas cell from the upstream end of the gas cell, is heated by passing through the first heating unit, and is quite high immediately before the catalyst. On the other hand, the simulated exhaust gas flowing through the cool line is supplied directly before the catalyst without passing through the first heating unit, and thus is about room temperature immediately before the catalyst.

Thus, the flow rate to Q ₁ simulated exhaust gas flowing through the hot line, so that the flow rate Q ₂ of the simulated exhaust gas flowing through the cool lines, the flow rate ratio Q _{1 /} Q ₂ becomes large in the heating process, the flow rate ratio Q ₁ is in the cooling process / Q ₂ are controlled so as to become smaller, thereby, the temperature elevation of the simulated exhaust gas immediately before the catalyst are controlled.

However, in this device, the temperature rise and fall of the simulated exhaust gas immediately before the catalyst is controlled by controlling the mixing ratio of the high temperature simulated exhaust gas and the simulated exhaust gas at room temperature. However, the temperature change of the exhaust gas immediately before the catalyst in the exhaust gas purification apparatus of the vehicle running in the test mode cannot be accurately reproduced.

Japanese Patent No. 3927399

Therefore, an object of the present invention is to make it possible to raise and lower the temperature of the simulated exhaust gas immediately before the exhaust gas purification catalyst at high speed.

In order to solve the above problems, according to the present invention, an apparatus for evaluating the performance of an exhaust gas purification catalyst, which is connected to a gas introduction pipe into which simulated exhaust gas is introduced from one end side and the other end of the gas introduction pipe. A gas cell in which the exhaust gas purifying catalyst is accommodated, an infrared heating unit disposed at intervals outside the gas introduction pipe and the gas cell, and a constant upstream side from the other end of the gas introduction pipe A cooling unit that cools the length or a region extending from the gas cell side to the gas introduction pipe side over a certain length, and a space between the gas cell and the infrared heating unit, and the cooling unit A light shielding plate extending downstream from the vicinity of the downstream end of the region to be cooled, and the exhaust gas purification catalyst is cooled by the cooling unit in the gas cell. The apparatus is further downstream and is accommodated in a region where infrared rays are shielded by the light shielding plate, and the apparatus further has a space upstream from the exhaust gas purification catalyst in the region where the infrared rays are shielded in the gas cell. The cooling unit is controlled according to a temperature sensor arranged in an open position and a simulated exhaust gas temperature setting value at a predetermined position of the temperature sensor, and the infrared heating unit is controlled based on a detection signal from the temperature sensor. A control unit that performs cooling by the cooling unit at all times, and the cooling output of the cooling unit and the heating output of the infrared heating unit are controlled by the control unit, whereby the exhaust gas purification catalyst An apparatus is provided wherein the temperature of the simulated exhaust gas immediately before is controlled so as to coincide with the simulated exhaust gas temperature set value.

According to a preferred embodiment of the present invention, the cooling unit is fixed to the gas introduction pipe, or the gas cell and the gas introduction pipe over the predetermined length, and the outer space of the gas introduction pipe, or the gas cell. And a refrigerant reservoir surrounding the outer space of the gas introduction pipe in a sealed state, wherein the refrigerant reservoir is formed with at least one refrigerant inlet and a refrigerant outlet, and the cooling unit further includes a refrigerant supply source, One end connected to the refrigerant supply source, the other end connected to the refrigerant inlet of the refrigerant reservoir, a refrigerant discharge line connected to the refrigerant outlet of the refrigerant reservoir, and the refrigerant supply pipeline And a flow rate control unit that controls the flow rate of the refrigerant, and the cooling output of the cooling unit is determined by the flow rate of the refrigerant supplied from the refrigerant supply source to the refrigerant supply line, The medium is constantly injected from the refrigerant inlet of the refrigerant reservoir toward the gas introduction pipe, or the gas introduction pipe and the gas cell, and the outer peripheral surface of the gas introduction pipe or the outer peripheral surface of the gas introduction pipe and the gas cell. Then, the refrigerant is discharged from the refrigerant outlet of the refrigerant reservoir, and the flow rate of the refrigerant is controlled by the control unit according to the simulated exhaust gas temperature set value, and at the same time based on the detection value of the temperature sensor. The heating output of the infrared heating unit is controlled by the control unit.

According to another preferred embodiment of the present invention, the control of the flow rate of the refrigerant by the control unit divides the possible range of the simulated exhaust gas temperature setting value into a plurality of temperature zones, and cools the temperature for each temperature zone. The necessary flow rate of the refrigerant is set in advance, it is determined each time the temperature range to which the simulated exhaust gas temperature set value belongs, and the flow rate of the refrigerant corresponding to the temperature range is determined from the refrigerant supply source. This is done by supplying the refrigerant supply pipe.

According to still another preferred embodiment of the present invention, the infrared heating unit is configured so that the heating output is not required to be soft-started by the infrared heating unit except when the apparatus is activated. Control is performed so as not to fall below a preset minimum value.
According to still another preferred embodiment of the present invention, the control for preventing the heating output of the infrared heating unit from being equal to or lower than the minimum value is performed by setting a predetermined range of detection values of the temperature sensor to a plurality of temperatures. The temperature is divided into bands, the minimum value of the heating output is set in advance for each temperature band, the temperature sensor detection value is determined each time, and the infrared heating unit The heating output does not fall below the minimum value corresponding to the temperature range.

According to still another preferred embodiment of the present invention, the refrigerant reservoir is fixed to the outer periphery of the other end of the gas introduction pipe or the outer periphery of the gas cell in a sealed state, A second annular flange fixed in a sealed state on the outer periphery of the gas introduction pipe at a position away from the first annular flange upstream by the predetermined length; and the first and second annular members A cylindrical side wall extending between the flanges and connecting the outer peripheral edges of the first and second annular flanges.

According to still another preferred embodiment of the present invention, the refrigerant comprises a liquid refrigerant, a gaseous refrigerant or a mixture thereof.
According to still another preferred embodiment of the present invention, the refrigerant consists of pure water mixed with air or nitrogen.

According to still another preferred embodiment of the present invention, the flow rate control unit comprises a flow rate control valve disposed in the middle of the refrigerant supply line.
According to still another preferred embodiment of the present invention, the flow rate control unit is connected to the refrigerant supply source, and is arranged in the middle of the main pipe line for circulating the refrigerant, and from the main pipe line to the refrigerant. And at least one branch valve or branch valve for branching the supply line.

According to still another preferred embodiment of the present invention, the refrigerant discharge line is connected to the refrigerant supply source via a heat exchanger, and the refrigerant discharged from the refrigerant reservoir is predetermined by the heat exchanger. Then, it is returned to the refrigerant supply source.

According to the present invention, the gas introduction pipe and the gas cell are heated by the infrared heating unit, and the vicinity of the simulated exhaust gas inlet of the gas cell is always cooled by the cooling unit, so that the simulated exhaust gas temperature setting at a predetermined temperature sensor position is set. The cooling output of the cooling unit is controlled according to the value, and the heating output of the infrared heating unit is controlled based on the detection value of the temperature sensor placed immediately before the exhaust gas purification catalyst, so the infrared heating unit is always operated at high output When the simulated exhaust gas temperature set value is in the low temperature range, the cooling output of the cooling unit is set to a high output, and when it is in the high temperature range, the cooling output of the cooling unit is set to a low output to reduce the temperature of the simulated exhaust gas. As a result, the temperature of the simulated exhaust gas immediately before the exhaust gas purification catalyst is changed in all temperature ranges from the low temperature range to the high temperature range. It can be raised and lowered at a rate.

It is a longitudinal cross-sectional view of the exhaust gas purification catalyst performance evaluation apparatus by one Example of this invention. It is a longitudinal cross-sectional view which shows schematic structure of one example of the shunt valve of the flow control unit of the apparatus of FIG. 6 is a graph showing an example of a temperature change of the simulated exhaust gas immediately before the exhaust gas purification catalyst when the raising and lowering of the simulated exhaust gas temperature set value is repeated in the exhaust gas purification catalyst performance evaluation apparatus according to one embodiment of the present invention. Using the same device that acquired the data in the graph of FIG. 3, the exhaust gas emission just before the catalyst in the exhaust gas purification device of the vehicle running in the LA4 cold start test mode (gasoline engine vehicle with a displacement of 2400 cc) is used. It is the graph which plotted the experimental data at the time of experimenting to what extent temperature change can be reproduced. When the simulated exhaust gas temperature set value is raised and lowered at a constant cycle in the range of 300 to 600 ° C. using the same apparatus that acquired the data of the graph of FIG. 3 (temperature gradient at the time of temperature increase = 60 It is the graph which showed the temperature change of the simulation exhaust gas just before an exhaust gas purification catalyst of (degreeC / sec, temperature gradient at the time of temperature fall = 25 degreeC / sec). Using the same apparatus that acquired the data of the graph of FIG. 3, the simulated exhaust gas temperature set value is maintained immediately before the exhaust gas purification catalyst when maintained for a certain time at 30 ° C., 50 ° C., and 80 ° C., respectively. It is the graph which showed the temperature change of the simulation exhaust gas.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a longitudinal sectional view showing the configuration of an exhaust gas purification catalyst performance evaluation apparatus according to one embodiment of the present invention.
Referring to FIG. 1, an exhaust gas purification catalyst performance evaluation apparatus according to the present invention is connected to a gas introduction pipe 1 into which simulated exhaust gas is introduced from one end 1a side, and the other end 1b of the gas introduction pipe 1, and exhaust gas purification is provided inside. A gas cell 2 in which the catalyst 3 is accommodated, and an infrared heating unit 4 disposed at intervals outside the gas introduction pipe 1 and the gas cell 2 are provided.

In this embodiment, the gas cell 2 includes a catalyst housing tube 2a having a larger diameter than the gas introduction tube 1, a tapered tube 2b connecting the gas introduction tube 1 and the catalyst housing tube 2a, and an infrared heating unit. 4 includes a cylindrical infrared furnace surrounding the gas introduction pipe 1 and the gas cell 2, but the configurations of the gas cell 2 and the infrared heating unit 4 are not limited thereto.

The exhaust gas purifying catalyst performance evaluation apparatus according to the present invention also includes cooling

units

6a and 6b for cooling a region extending over a certain length from the gas cell 2 side to the gas introduction pipe 1 side. In this case, the cooling

units

6a and 6b may be configured to cool the region extending from the other end 1b of the gas introduction pipe 1 over the predetermined length on the upstream side.

In this embodiment, the cooling

units

6a and 6b are fixed to the outside of the gas cell 2 and the gas introduction pipe 1 over the predetermined length, and surround the outer space of the gas cell 2 and the gas introduction pipe 1 in a sealed state. It has.
The refrigerant reservoir 7 has a first annular flange 7a fixed in a sealed state on the outer periphery of the gas cell 2, and the gas introduction pipe 1 at a position away from the first annular flange 7a by the predetermined length upstream. The outer peripheral edges of the first and second

annular flanges

7a and 7b extend between the second annular flange 7b and the first and second

annular flanges

7a and 7b. And a cylindrical side wall 7c for connecting the two. In the refrigerant reservoir 7, at least one refrigerant inlet 7d and a refrigerant outlet 7e are formed.

The cooling

units

6 a and 6 b further include a refrigerant supply source 8, a refrigerant supply line 9 having one end connected to the refrigerant supply source 8 and the other end connected to the refrigerant inlet 7 d of the refrigerant reservoir 7, A refrigerant discharge line 10 connected to the refrigerant outlet 7e and a flow rate control unit 11 arranged in the middle of the refrigerant supply line 9 and controlling the flow rate of the refrigerant are provided.
In this case, the refrigerant discharge pipe 10 is connected to the refrigerant supply source 8 via a heat exchanger, and the refrigerant discharged from the refrigerant reservoir 7 is cooled to a predetermined temperature by the heat exchanger, and then the refrigerant supply source 8 is supplied. You may make it return.

In this embodiment, the refrigerant is composed of pure water mixed with air, and the refrigerant supply source 8 includes a water tank 8 a, a pump 8 b, and an air supply branched and connected in the middle of the refrigerant supply pipe 8. It consists of a conduit 15. In this case, pure water mixed with nitrogen instead of air may be used as the refrigerant.
The flow rate control unit 11 connects the water tank 8a and the pump 8b, and is disposed in the middle of the main pipeline 11a for circulating pure water and the main pipeline 11a, and at least branches the refrigerant supply pipeline 9 from the main pipeline 11a. It consists of one branch valve (or branch valve) 11b.

FIG. 2 is a longitudinal sectional view showing a schematic configuration of an example of the diversion valve. Referring to FIG. 2, the diversion valve 11b includes a base 28, and a cylindrical housing 20 that is fixed on the base 28 and includes a columnar cavity 21 inside, with both end openings closed. is doing. In the central part of the side wall of the housing 20, there is provided an inlet pipe line 22 having one end opened to the cavity 21 and the other end connected to the main pipe line 11 a, and one end part of the side wall of the housing 20 has one end. A first outlet pipe 23 that opens to the cavity 21 and has the other end connected to the main pipe 11a is provided. One end opens to the cavity 21 at the other end of the side wall of the housing 20, and the other end is a refrigerant. A second outlet line 24 connected to the supply line 9 is provided.

Further, in the cavity 21, a valve body 25 having a circular cross section and gradually tapered from both ends toward the center is disposed, and the first valve seat 20a on the first outlet conduit 23 side, Between the 2nd valve seat 20b by the side of 2 outlet pipeline 24, it arrange | positions so that a reciprocating motion is possible to an axial direction. On both end surfaces of the valve body 25, rods 26 extending in the axial direction are projected. Each rod 26 protrudes outside through the end face of the housing 20 and is supported in a sealed state by a bearing provided in the housing 20 so as to be capable of reciprocating in the axial direction. Further, a linear actuator 27 is mounted on the base 28 and connected to the tip of one rod 26.

The linear actuator 27 causes the valve body 25 to reciprocate in the axial direction between the first valve seat 20a and the second valve seat 20b, and supply refrigerant according to the position of the valve body 25 relative to the

valve seats

20a and 20b. The valve opening on the side of the pipe 9 and the valve opening on the side of the main pipe 11a change (when the end of the valve body 25 is located at the position of the

valve seats

20a, 20b, the opening becomes the minimum, and the

valve seats

20a, 20b When the center of the valve body 25 is located at the position of (2), the opening degree is maximized).

The configuration of the flow rate control unit 11 is not limited to this embodiment, and the flow rate control unit 11 may be constituted by a flow rate control valve such as a mass flow controller disposed in the middle of the refrigerant supply line 9, for example. .
Further, the configuration of the refrigerant is not limited to this example, and any known appropriate liquid refrigerant, gaseous refrigerant, or a mixture thereof can be used as the refrigerant.
Further, the configuration of the

cooling units

6a and 6b is not limited to this example, and any configuration is possible as long as the cooling output can be appropriately controlled and is suitable for cooling near the inlet of the gas cell 2. You may do it.

In the space 5, a light shielding plate 12 that shields infrared rays from the infrared heating unit 4 is disposed, and is located at the downstream end of the region cooled by the cooling

units

6 a and 6 b (in this embodiment, the refrigerant reservoir 7. It extends from the vicinity of the downstream end) to the downstream side. In this embodiment, the light shielding plate 12 has a cylindrical shape that surrounds the outside of the gas cell 2 with a space therebetween.
The exhaust gas purification catalyst 3 is accommodated in a region downstream of the region cooled by the cooling

units

6 a and 6 b in the gas cell 2 and where infrared rays are blocked by the light shielding plate 12.

The exhaust gas purifying catalyst performance evaluation apparatus according to the present invention further includes a temperature sensor 13 disposed at an upstream side from the exhaust gas purifying catalyst 3 in a region where infrared rays in the gas cell 2 are blocked, and a predetermined temperature. The

cooling unit

6 a, 6 b is controlled according to the simulated exhaust gas temperature set value at the position of the sensor 13, and the control unit 14 that controls the infrared heating unit 4 based on a detection signal from the temperature sensor 13 is provided.

In this embodiment, the cooling outputs of the

cooling units

6a and 6b are determined by the flow rate of the refrigerant supplied from the refrigerant supply source 8 to the refrigerant supply line 9, and the flow rate of the refrigerant is determined by the opening of the diversion valve 11b (diversion valve). It is controlled by adjusting the opening of the refrigerant supply pipe 9 side in 11b.
And after a refrigerant | coolant is always injected toward the gas introduction pipe 1 and the gas cell 2 from the refrigerant inlet 7d of the refrigerant reservoir 7, and flows along the outer peripheral surface of the gas introduction pipe 1 and the gas cell 2, the refrigerant of the refrigerant reservoir 7 While being discharged from the outlet 7e, the flow rate of the refrigerant is controlled by the control unit 14 according to the simulated exhaust gas temperature set value, and at the same time, the heating output of the infrared heating unit 4 is controlled by the control unit 14 based on the detection value of the temperature sensor 13. Thereby, the temperature of the simulated exhaust gas immediately before the exhaust gas purification catalyst 3 is controlled so as to coincide with the simulated exhaust gas temperature set value.

Thus, according to the exhaust gas purification catalyst performance evaluation apparatus of the present invention, the gas introduction pipe 1 and the gas cell 2 are heated by the infrared heating unit 4, and the vicinity of the simulated exhaust gas inlet of the gas cell 2 is constantly cooled by the cooling

units

6a and 6b. Since the cooling output of the

cooling units

6a and 6b is controlled according to the simulated exhaust gas temperature setting value at the position of the temperature sensor 13 determined in advance, and at the same time, the heating output of the infrared heating unit is controlled based on the detection value of the temperature sensor 13 When the simulated exhaust gas temperature set value is in the low temperature region while the infrared heating unit 4 is always operated at a high output, the cooling output of the

cooling units

6a and 6b is set to a high output, and when in the high temperature region, the cooling unit 6a. By reducing the cooling output of 6b, the temperature of the simulated exhaust gas can be raised and lowered. As a result, the simulated exhaust gas immediately before the exhaust gas purification catalyst 3 can be increased. The temperature can be raised or lowered at high speed at all temperatures region from low temperature region to high temperature region.

In this embodiment, the control of the refrigerant flow rate by the control unit 14 divides the possible range of the simulated exhaust gas temperature set value into a plurality of temperature zones, and the refrigerant flow rate required for cooling for each temperature zone (of the shunt valve 11b). Opening degree) is set in advance, it is determined each time the simulated exhaust gas temperature set value belongs, and the opening degree of the diverter valve 11b is adjusted to a value corresponding to the temperature range to supply the refrigerant. The amount of refrigerant corresponding to the refrigerant supply line 9 is supplied from the source 8.

In addition, the infrared heating unit 4 causes the control unit 14 to reduce the heating output below a preset minimum value so as not to require the soft start of the infrared heating unit 4 except when the exhaust gas purification catalyst performance evaluation device is activated. It is controlled not to become.
In this control, preferably, the range of detection values of the temperature sensor 13 determined in advance is divided into a plurality of temperature zones, the minimum value of the heating output is set in advance for each temperature zone, and the detection of the temperature sensor 13 is performed. The temperature range to which the value belongs is determined each time so that the heating output of the infrared heating unit 4 does not fall below the minimum value corresponding to the temperature range.

The control by the control unit 14 is executed as follows.
First, the range that the simulated exhaust gas temperature set value can take is set in advance as 0 to 1000 ° C. Regarding the control of the flow rate of the refrigerant, as shown in Table 1, the range of the temperature set value is 0 to 200 ° C. (temperature zone No. 1), 201 to 300 ° C. (temperature zone No. 2), 301 -350 ° C. (temperature zone No. 3), 351-400 ° C. (temperature zone No. 4), 401-450 ° C. (temperature zone No. 5), 451-500 ° C. (temperature zone No. 6), 501-550 10 temperature zones: ℃ (temperature zone No. 7), 551 to 600 ° C. (temperature zone No. 8), 601 to 700 ° C. (temperature zone No. 9), 701 to 1000 ° C. (temperature zone No. 10) It is divided. For each temperature zone, the opening degree of the diversion valve 11b (the opening degree on the refrigerant supply line 9 side in the diversion valve 11b) is 95% (temperature zone No. 1), 85% (temperature zone No. 2), 75% (temperature zone No. 3), 65% (temperature zone No. 4), 55% (temperature zone No. 5), 45% (temperature zone No. 6), 35% (temperature zone No. 7), It is preset such as 25% (temperature zone No. 8), 15% (temperature zone No. 9), 5% (temperature zone No. 10).

As for the heating output of the infrared heating unit 4, the range of the detected value of the temperature sensor 13 determined in advance is 0 to 1000 ° C., as shown in Table 2, below 0 to 35 ° C. (temperature zone No. 1), 35 ° C. to less than 100 ° C. (temperature zone No. 2), 100 ° C. to less than 150 ° C. (temperature value No. 3), 150 ° C. to less than 200 ° C. (temperature zone No. 4), 200 ° C. to 1000 ° C. It is divided into five temperature zones of ° C. (temperature zone No. 5). For each temperature zone, the minimum heating output value is 0% of the maximum heating output value (temperature zone No. 1), 5% of the maximum heating output value (temperature zone No. 2), and 10% of the maximum heating output value. % (Temperature zone No. 3), 15% of the maximum heating output value (temperature zone No. 4), and 20% of the maximum heating output value (temperature zone No. 5).
In this case, the temperature zone No. in which the minimum value of the heating output is 0% of the maximum heating output. In 1 (corresponding to the start of the exhaust gas purification catalyst performance evaluation apparatus of the present invention), the infrared heating unit 4 must be soft-started.

FIG. 3 is a graph showing an example of a temperature change when the temperature of the simulated exhaust gas immediately before and after the exhaust gas purification catalyst is repeatedly raised and lowered in this specific example. In the graph of FIG. 3, the vertical axis represents temperature (° C.), the horizontal axis represents elapsed time (sec), and the curve C represents temperature change. Moreover, the opening degree of the diversion valve 11b in each temperature zone is shown on the right side of the graph.

Referring to FIG. 3, first, after the start of the exhaust gas purification catalyst performance evaluation apparatus of the present invention, the simulated exhaust gas temperature set value is raised to around 300 ° C. (0 to 40 seconds). In this temperature raising process, after the apparatus is started up (the temperature at the time of starting is about room temperature), the infrared heating unit 4 is soft-started until the simulated exhaust gas temperature set value reaches 35 ° C., and during that time, the shunt valve 11b is opened. The degree is set to 95%. Next, when the simulated exhaust gas temperature set value is in the range of 35 ° C. or more to 300 ° C., the infrared heating unit 4 is operated at a high output (above the minimum heating output), while the opening of the diversion valve 11b is the simulated exhaust gas temperature set value. Is set to 95% up to 200 ° C., and is set to 85% when the simulated exhaust gas temperature set value is in the range of 201 to 300 ° C.

Thereafter, the simulated exhaust gas temperature set value is lowered from about 300 ° C. to about 250 ° C. (40 to 50 seconds). In the temperature lowering process, the heating output of the infrared heating unit 4 is maintained at the minimum heating output (20% of the maximum heating output), and the opening degree of the flow dividing valve 11b is set to 85%.
Next, the simulated exhaust gas temperature set value is raised from around 250 ° C. to around 350 ° C. (50 to 55 seconds). In this temperature raising process, the infrared heating unit 4 is again operated at a high output (more than the minimum heating output), while the opening of the diverter valve 11b is 85 when the simulated exhaust gas temperature set value is in the range of 250 to 300 ° C. %, In the range of 301 to 350 ° C., it is set to 75%. At this time, the infrared heating unit 4 does not need to be soft-started, and thus can raise the temperature at a high speed.

Thus, by controlling the flow rate of the refrigerant (cooling output of the

cooling units

6a and 6b) and the heating output of the infrared heating unit 4, the temperature of the simulated exhaust gas immediately before the exhaust gas purification catalyst is raised and lowered at a high speed.

FIG. 4 shows a state immediately before the catalyst in the exhaust gas purification apparatus of a vehicle (gasoline engine vehicle with a displacement of 2400 cc) running in the LA4 cold start test mode using the same apparatus that acquired the data of the graph of FIG. It is the graph which plotted the experimental data at the time of experimenting to what extent the temperature change of the exhaust gas in can be reproduced.
In the graph of FIG. 4, the vertical axis represents temperature (° C.) and vehicle speed (km / h), and the horizontal axis represents elapsed time (sec). A curve C1 drawn with a solid line represents a temperature change of the simulated exhaust gas in the apparatus of the present invention, a curve C2 drawn with a broken line represents a temperature change of the exhaust gas of the actual vehicle, and a curve C3 represents a speed change of the actual vehicle. Represents.
From the graph of FIG. 4, according to the exhaust gas purification catalyst performance evaluation apparatus of the present invention, it is possible to accurately reproduce the temperature change of the exhaust gas immediately before the catalyst in the exhaust gas purification apparatus of the vehicle running in the test mode. Recognize.

FIG. 5 shows the case where the simulated exhaust gas temperature set value is raised and lowered at a constant cycle in the range of 300 to 600 ° C. using the same apparatus that acquired the data of the graph of FIG. It is the graph which showed the temperature change of the simulation exhaust gas just before an exhaust gas purification catalyst of a temperature gradient = 60 degreeC / sec and the temperature gradient at the time of temperature fall = 25 degreeC / sec). From the graph of FIG. 5, it can be seen that according to the exhaust gas purification catalyst performance evaluation apparatus of the present invention, the temperature of the simulated exhaust gas immediately before the exhaust gas purification catalyst can be raised and lowered in units of 1 second.

FIG. 6 shows the exhaust gas purification when the simulated exhaust gas temperature set value is maintained at 30 ° C., 50 ° C., and 80 ° C. for a certain period of time using the same apparatus that acquired the data of the graph of FIG. It is the graph which showed the temperature change of the simulation exhaust gas just before a catalyst. From the graph of FIG. 6, it can be seen that according to the exhaust gas purifying catalyst performance evaluation apparatus of the present invention, the temperature of the simulated exhaust gas can be raised and lowered stably even in a low temperature region of 100 ° C. or lower.

DESCRIPTION OF SYMBOLS 1 Gas introduction pipe 1a One end 1b Other end 2 Gas cell 2a Catalyst accommodating pipe 2b Taper pipe 3 Exhaust gas purification catalyst 4 Infrared heating part 5

Space

6a, 6b Cooling part 7 Refrigerant reservoir 7a First annular flange 7b Second annular flange

7c Side wall

7d Refrigerant inlet 7e Refrigerant outlet 8 Refrigerant supply source 8a Water tank 8b Pump 9 Refrigerant supply line 10 Refrigerant discharge line 11 Flow rate control unit 11a Main line 11b Flow dividing valve 12 Light shielding plate 13 Temperature sensor 14 Control unit 15 Air supply line 20 Housing 20a First valve seat 20b Second valve seat 21 Cavity 22 Inlet conduit 23 First outlet conduit 24 Second outlet conduit 25 Valve element 26 Rod 27 Linear actuator 28 Base

Claims

An apparatus for evaluating the performance of an exhaust gas purification catalyst,
A gas introduction pipe into which simulated exhaust gas is introduced from one end side;
A gas cell connected to the other end of the gas introduction pipe and containing the exhaust gas purification catalyst therein;
An infrared heating unit disposed at intervals outside the gas introduction pipe and the gas cell;
A cooling section that cools a region extending from the other end of the gas introduction pipe to a certain length upstream, or a certain length extending from the gas cell side to the gas introduction pipe;
A light-shielding plate disposed in a space between the gas cell and the infrared heating unit and extending from the vicinity of the downstream end of the region cooled by the cooling unit to the downstream side, , In the region downstream of the region cooled by the cooling unit in the gas cell, the infrared ray being blocked by the light shielding plate,
The apparatus further comprises:
A temperature sensor disposed at an upstream side from the exhaust gas purification catalyst in a region where the infrared ray is blocked in the gas cell;
A control unit that controls the cooling unit in accordance with a simulated exhaust gas temperature setting value of the position of the temperature sensor determined in advance, and controls the infrared heating unit based on a detection signal from the temperature sensor. The cooling by the cooling unit is always performed, and the cooling output of the cooling unit and the heating output of the infrared heating unit are controlled by the control unit, whereby the temperature of the simulated exhaust gas immediately before the exhaust gas purification catalyst is controlled. The apparatus is controlled to match the simulated exhaust gas temperature set value.
The cooling part is
A refrigerant reservoir fixed to the gas introduction pipe or the gas cell and the gas introduction pipe over the certain length and surrounding the outer space of the gas introduction pipe or the outer space of the gas cell and the gas introduction pipe in a sealed state. The refrigerant reservoir is formed with at least one refrigerant inlet and a refrigerant outlet,
The cooling unit further includes:
A refrigerant supply source;
A refrigerant supply line having one end connected to the refrigerant supply source and the other end connected to a refrigerant inlet of the refrigerant reservoir;
A refrigerant discharge line connected to a refrigerant outlet of the refrigerant reservoir;
A flow rate control unit that is disposed in the middle of the refrigerant supply line and controls the flow rate of the refrigerant,
The cooling output of the cooling unit is determined by the flow rate of the refrigerant supplied from the refrigerant supply source to the refrigerant supply pipe, and the refrigerant is always supplied from the refrigerant inlet of the refrigerant reservoir to the gas introduction pipe or the gas introduction pipe. And is injected toward the gas cell and flows through the outer peripheral surface of the gas introduction pipe or the outer peripheral surface of the gas introduction pipe and the gas cell, and is then discharged from the refrigerant outlet of the refrigerant reservoir, and the simulated exhaust gas The flow rate of the refrigerant is controlled by the control unit according to a temperature set value, and simultaneously, the heating output of the infrared heating unit is controlled by the control unit based on a detection value of the temperature sensor. The device described in 1.
The control of the flow rate of the refrigerant by the control unit divides the possible range of the simulated exhaust gas temperature set value into a plurality of temperature zones, and presets the flow rate of the refrigerant necessary for cooling for each temperature zone. , It is determined each time the simulated exhaust gas temperature set value belongs to which temperature range, and a refrigerant having a flow rate corresponding to the temperature range is supplied from the refrigerant supply source to the refrigerant supply line. The apparatus according to claim 2.
The infrared heating unit is controlled by the control unit so that the heating output does not become lower than a preset minimum value so as not to require a soft start of the infrared heating unit except when the apparatus is activated. The device according to any one of claims 1 to 3, wherein
The control to prevent the heating output of the infrared heating unit from being equal to or lower than the minimum value is performed by dividing a range of detection values of the temperature sensor determined in advance into a plurality of temperature zones, and the heating output for each temperature zone. Is set in advance, and it is determined each time the temperature sensor detection value belongs, and the heating output of the infrared heating unit is equal to or lower than the minimum value corresponding to the temperature zone. 5. The device according to claim 4, characterized in that it consists of preventing the failure.
The refrigerant reservoir is
A first annular flange fixed in a sealed state on the outer periphery of the other end of the gas introduction pipe or on the outer periphery of the gas cell;
A second annular flange fixed in a state of being sealed to the outer periphery of the gas introduction pipe at a position away from the first annular flange by the predetermined length upstream;
A cylindrical side wall extending between the first and second annular flanges and connecting outer peripheral edges of the first and second annular flanges is provided. Item 6. The device according to any one of Items 5.
The apparatus according to any one of claims 2 to 6, wherein the refrigerant comprises a liquid refrigerant, a gaseous refrigerant, or a mixture thereof.
The apparatus according to any one of claims 2 to 6, wherein the refrigerant is made of pure water mixed with air or nitrogen.
The apparatus according to any one of claims 2 to 8, wherein the flow rate control unit includes a flow rate adjusting valve disposed in the middle of the refrigerant supply pipe.
The flow rate control unit includes:
A main line connected to the refrigerant supply source for circulating the refrigerant;
9. The apparatus according to claim 2, further comprising at least one branching valve or branching valve that is arranged in the middle of the main pipeline and branches the refrigerant supply pipeline from the main pipeline. The device described in 1.
The refrigerant discharge line is connected to the refrigerant supply source via a heat exchanger, and after the refrigerant discharged from the refrigerant reservoir is cooled to a predetermined temperature by the heat exchanger, the refrigerant supply source The device according to any one of claims 2 to 10, wherein the device is returned.