Emission measurement instrument with self-test function

Abstract

To simplify the self-testing of emission measuring instruments, it is stipulated that: a self-testing unit (20) is provided, and a first coupler component (21, 21a) for connecting couplers is arranged on the self-testing unit (20). The second coupler component (22) for connecting couplers is arranged on the probe tip (2) of the exhaust gas probe (1). In order to perform self-testing, the second coupler component (22) of the probe tip (2) can be connected to the first coupler component (21, 21a) on the self-testing unit (20).

Description

Technical Field

[0001] This invention relates to an emission measuring instrument with a self-testing function, wherein an exhaust gas pipeline is connected to the emission measuring instrument, the exhaust gas pipeline is connected to an emission measuring unit via a measuring pipeline in the emission measuring instrument, and an exhaust gas probe for exhaust gas extraction is provided at the end of the exhaust gas pipeline opposite to the emission measuring instrument. This invention also relates to a method for performing self-testing using such an emission measuring instrument. Background Technology

[0002] Used to measure exhaust emissions, such as hydrocarbons (HC), carbon monoxide (CO), carbon dioxide (CO2), and nitrogen oxides (NOx) from internal combustion engines or industrial processes. x Emission measuring instruments for fine dust and other pollutants are well-known. Such instruments exist in various implementations and based on various known measurement principles. All emission measuring instruments use an exhaust gas probe to extract exhaust gas from the exhaust gas stream and deliver it to the instrument. Within the instrument, the extracted exhaust gas can be treated as needed (e.g., water removal, removal of volatile components, etc.), diluted as needed (e.g., in a dilution channel), and delivered to one or more measurement stages. Typically, the exhaust gas probe is introduced directly into the vehicle's exhaust pipe and anchored during the measurement process, for example, by clamping.

[0003] To ensure the proper operation of emission measuring instruments, regular self-testing is required. This can be achieved through compensation, such as adjusting the zero point of the measurement by zeroing with a zero gas (a pure gas without emission components, such as filtered ambient air) or by calibration using a calibration gas (a gas with defined emission components). It is also common practice to regularly perform leak checks on the probe system (the exhaust gas probe with the exhaust gas line leading to the emission measuring instrument) or the entire gas path within the emission measuring instrument. This is particularly advantageous during plant operation and when used by maintenance personnel, as it allows for both compensation and leak checks to be performed as easily as possible.

[0004] EP530566A1 proposes a shut-off valve in the area of ​​the measuring probe to seal the exhaust gas line. For a leak test, the exhaust gas line is filled with exhaust gas, the concentration of emission components in the exhaust gas is measured, and then the shut-off valve is closed. The emission components are then measured again over a certain period. If a change in the monitored emission components occurs, a leak is identified. A disadvantage is that, in the case of a motor vehicle, the exhaust gas probe for the leak test must be installed in the end pipe of the exhaust system, and the internal combustion engine must be running. Typically, however, the leak test is only performed once a day, for example, at the beginning or end of workshop operation. Therefore, the motor vehicle on which the test is performed is not always available. Furthermore, it is cumbersome to additionally place the exhaust gas probe in the exhaust gas flow for this test. While a leak test before a specific emission measurement is possible, it is often forgotten during normal use of the emission measuring instrument, such as during workshop operation, and is therefore unreliable. In addition, compensation (zeroing, calibration) cannot be performed as a result. Another disadvantage is placing the valve in the area at the probe tip, where high temperatures and the risk of contamination exist. The valve must be designed for these adverse conditions, which increases cost and expense.

[0005] Therefore, it has been considered to place a particulate filter (EPA filter) or a suspended matter filter (HEPA filter) on the exhaust gas probe and thus perform measurements using an emission measuring instrument. In this way, zeroing can be performed using filtered ambient air. Similarly, the exhaust gas probe can be connected to a gas surface with a calibration gas for calibration. For a seal check, the exhaust gas probe is sealed with a sealing plug, a negative pressure is generated, and the subsequent pressure rise is monitored. If the pressure rises too quickly, a leak can be identified. However, the arrangement of the filters, the connection to the calibration gas, and the use of the sealing plug are cumbersome and make the operation of the emission measuring instrument difficult. In particular, separate components are required for this purpose, which are frequently misplaced or lost during the normal operation of the emission measuring instrument, especially in workshop operations. Summary of the Invention

[0006] Therefore, the objective of this invention is to simplify the self-testing of emission measuring instruments.

[0007] This task is solved by setting up a self-test unit, on which a first coupler component for connecting a coupler is arranged, and a second coupler component for connecting the coupler is arranged on the probe tip of the exhaust gas probe. For self-testing, the second coupler component at the probe tip can be connected to the first coupler component on the self-test unit. Through this dual function of the exhaust gas probe tip—that is, exhaust gas extraction on the one hand and as part of the connecting coupler on the other—self-testing can be easily implemented. For this purpose, it is only necessary to connect the first coupler component at the probe tip to the first coupler component on the self-test unit. The self-test unit has all the additional features required for implementing self-testing, particularly for sealing checks and / or zeroing or calibration. No additional parts or components need to be processed for self-testing.

[0008] In the first variant, the probe tip of the exhaust gas probe is implemented as a second coupler component. In other words, the second coupler component and the probe tip are implemented as a single piece or constitute a common component, with the second coupler component being the probe tip.

[0009] When measuring vehicle exhaust gases, the exhaust gas probe is susceptible to contamination during use. Therefore, in the second variant, the second coupler component is detachably mounted on the probe tip. In other words, the second coupler component can be detachably connected to the exhaust gas probe. This allows the second coupler component to be easily removed for cleaning or replacement. It is also conceivable to install different types of couplers on the exhaust gas probe via this detachable connection. This can be particularly advantageous when the instrument is checked by a third party. Such instrument checking could be, for example, calibration performed by a metrology bureau or calibration in a calibration laboratory.

[0010] If the self-test unit is integrated into the emissions measuring instrument, a particularly simple and compact emissions measuring instrument can be achieved. Alternatively, the self-test unit can also be configured as a separate component of the emissions measuring instrument with its own housing.

[0011] For reliable coupling, it is advantageous to provide a first locking member on the first coupler component and a second locking member on the second coupler component. When the first and second coupler components are connected to each other to manufacture a coupling, the first and second locking members cooperate to lock the first and second coupler components. Therefore, unintentional loosening of the coupling can be prevented to the greatest extent possible.

[0012] If the end of the first coupler component in the self-test unit is closed, then a seal check as a self-test can be easily achieved. Thus, a negative or overpressure can be easily generated in the probe system for a seal check.

[0013] Zeroing, adjustment, or calibration can be easily achieved when the first coupler component in the self-test unit is connected to the gas inlet of the self-test unit via a self-test line. If a filter is arranged in the self-test line between the first coupler component and the gas inlet, ambient air can be advantageously used for zeroing.

[0014] If a self-test line is provided in the self-test unit, which connects the first coupler component to the gas inlet on the self-test unit, and a controllable valve is arranged between the first coupler component and the gas inlet in the self-test unit, the valve can close the self-test line to perform a leak check or open the self-test line to perform zeroing or calibration, then both self-tests can be easily achieved.

[0015] To perform a leak test, a delivery pump and a pressure sensor are preferably installed in the measuring line. The delivery pump can generate overpressure or negative pressure. The pressure sensor is connected to the control unit of the emission measuring instrument, and the control unit evaluates the pressure change (curve) over time in the measuring line. When the pressure change over time exceeds a predetermined threshold, the control unit determines that the probe system is leaking. Since delivery pumps and pressure sensors are often installed in emission measuring instruments, these components can also be easily used to perform leak tests.

[0016] The delivery pump, which is typically present in emission measuring instruments, can also be advantageously used to deliver gas to the emission measuring unit via the gas inlet, self-test line, first coupler component, exhaust gas probe, and exhaust gas line for emission measurement in order to perform zeroing, adjustment, or calibration. Attached Figure Description

[0017] Next, please refer to the appendix. Figures 1 to 4 The invention is described in detail here, and the accompanying drawings exemplify, schematically and non-limitingly illustrate advantageous designs of the invention. Seen herein:

[0018] Figure 1 An emission measuring instrument with self-testing function according to the present invention is shown.

[0019] Figure 1a An emissions measuring instrument with an external self-test unit is shown.

[0020] Figure 2 An exhaust gas probe with a coupler component having a connecting coupler is shown according to the present invention.

[0021] Figure 3 Complementary coupler components on the self-test unit are shown, and

[0022] Figure 4An exhaust gas probe with a spacing retainer is shown. Detailed Implementation

[0023] Figure 1 An emission measuring instrument 10 with an exhaust gas conduit 4 is schematically shown, at the end of which an exhaust gas probe 1 is arranged. The exhaust gas probe 1 is introduced into the end pipe of a motor vehicle's exhaust system, for example, in a known manner, to extract exhaust gas from the end pipe. For this purpose, the exhaust gas probe 1 has at least one opening in the region of the probe tip 2, through which exhaust gas can flow into the exhaust gas probe 1. A flow channel is provided in the exhaust gas probe 1, connecting to the opening and the exhaust gas conduit 4, to guide the extracted exhaust gas to the exhaust gas conduit 4. The exhaust gas conduit 4 can be arranged at the end of the exhaust gas probe 1 opposite to the probe tip 2.

[0024] The extracted exhaust gas is guided through exhaust gas line 4 to the exhaust gas inlet connection 13 of the emission measuring instrument 10. The exhaust gas measurement line 14 leads from the exhaust gas inlet 13 to the measurement unit 12, where the prepared and emission measurements are performed. Flow regulation is typically also performed in the measurement unit 12 to provide a specific amount of exhaust gas for the emission measurement.

[0025] A delivery pump 11, such as a suction pump, is provided in the measuring line 14 to deliver exhaust gas through the measuring unit 12. The exhaust gas delivered through the emission measuring instrument 10 can be discharged at the exhaust outlet connection 15, for example, by being delivered to the environment or to a suction device. A control unit 16 is provided in the emission measuring instrument 10 to control and monitor the function of the emission measuring instrument 10, particularly by regulating the delivery pump 11 and controlling the measuring unit 12. The general structure of the emission measuring instrument 10 is well known and therefore will not be discussed in detail here, especially since it is not important to the present invention. For example, one possible (but not the only possible) embodiment of the emission measuring instrument 10 is described in WO2015 / 0044256A1.

[0026] Control unit 16 is typically implemented as processor-based hardware, such as a microcontroller, computer, or programmable control device. However, control unit 16 can also be implemented as an integrated circuit, such as an application-specific integrated circuit (ASIC) or a field-programmable gate array (FPGA). An implementation as a similar or analog electrical switching circuit is also conceivable. Combinations of these implementations are also conceivable.

[0027] To enable a simple self-test of the emission measuring instrument 10, a self-test unit 20 is provided according to the present invention. Figure 1In one embodiment, the self-test unit 20 is integrated into the emission measuring instrument 10, but it can also be implemented separately from the emission measuring instrument 10, i.e., as part of itself (e.g., in...). Figure 1a (As shown in the diagram). The self-test unit 20 may have its own control unit, but if a control device is required, the self-test unit 20 may also be controlled by the control unit 16 of the emission measuring instrument 10.

[0028] The self-test unit 20 includes a first coupler component 21 for connecting couplers. A second coupler component 22 for connecting couplers is formed by the exhaust gas probe 1. For example, the first coupler component 21 is a coupler socket, and the second coupler component 22 is a coupler plug, which is inserted into the coupler socket to establish a connection, or vice versa. Therefore, according to the invention, the exhaust gas probe 1 has a dual function: on the one hand, it extracts exhaust gas from the exhaust gas stream to be tested, and on the other hand, it forms a coupler component for connecting couplers to establish a connection with the self-test unit 20. The second coupler component 22 of the exhaust gas probe 1 can be connected to, for example, inserted into, the first coupler component 21 of the self-test unit 20. The self-test function is at least partially implemented in the self-test unit 20.

[0029] To form the second coupler component 22, the probe tip 2 of the exhaust gas probe 1 can be constructed in the form of the second coupler component 22. The second coupler component 22 is thus integrated into the exhaust gas probe 1. However, the probe tip 2 of the exhaust gas probe 1 can also be detachably connected to the second coupler component 22. For example, the probe tip 2 can be inserted into the gap of the coupling adapter forming the second coupler component 22. In this way, different second coupler components 22 can be easily equipped on the exhaust gas probe 1. Therefore, the second coupler component 22 is naturally connected to the exhaust gas probe, such that although the second coupler component 22 is detachable, it is still fixedly held on the exhaust gas probe 1 when in use. For example, the coupling adapter with the second coupler component 22 can be screwed onto or into the probe tip 2, wherein, of course, any other detachable force-locking or form-locking connection is also conceivable.

[0030] According to Figure 1 and Figure 1aIn this embodiment, a gas inlet 23 is provided on the self-test unit 20. This gas inlet is technically connected to the first coupler component 21 via a self-test conduit 26, so that as long as the second coupler component 22 of the exhaust gas probe 1 is connected to the first coupler component 21, gas can flow from the gas inlet 23 to the first coupler component 21 and from there continue to flow into the exhaust gas probe 1. A filter 24, such as a HEPA filter, and a controlled valve 25 may be arranged in the self-test conduit 26. Ambient air may be supplied at the gas inlet 23, for example. In this case, the filter 24 is provided so that the emission measuring instrument 10 is zeroed with filtered ambient air, as will be further described below. However, specific gases (e.g., via gas cylinders) may also be connected to the gas inlet 23, for example, to supply calibration or adjustment gases via the gas inlet 23. In this case, the filter 24 is not absolutely necessary.

[0031] For example, a controlled valve 25, implemented as a reversing valve (e.g., a two-position two-way reversing valve), is configured to release or close the flow through the self-test line 26. When the flow is released, the gas inlet 23 is connected to the first coupler component 21, allowing gas to flow from the gas inlet 23 to the first coupler component 21. If the flow is blocked, a leak test of the probe system (exhaust gas probe 1 and exhaust gas line 4) can be performed, as will be described below. If a leak test is not required, the controllable valve 25 can be omitted. The controllable valve 25 can be manually adjusted externally, or it can be controlled by the control unit 16 of the emission measuring instrument 10 or the control unit of the self-test unit 20 for switching purposes.

[0032] For example, a user interface 17 can be provided on the emission measuring instrument 10, through which the functions of the emission measuring instrument 10 can be controlled and self-tests can be initiated. For this purpose, the user interface 17 can be equipped with appropriate input and output units, such as buttons, sliders, knobs, keys, keyboards, mouse pads, displays, touch screens, etc.

[0033] The exhaust gas probe 1 according to the present invention has a probe tip 2 at a first axial end and a fixed section 3 for the exhaust gas pipeline 4 at an opposite axial end, such as in Figure 2 As shown in the diagram, the exhaust gas duct 4 is arranged in a suitable manner within the fixed section 3 of the exhaust gas probe 1. However, how this device is specifically implemented is not important to the present invention, and therefore will not be discussed in detail. The exhaust gas duct 4 may also be connected to the exhaust gas probe 1 in other ways.

[0034] The first coupler component 21 on the self-test unit 20 is equipped with a first locking component 6, such as in Figure 3As shown in the diagram. The probe tip 2 is implemented as a second coupler component 22 with a second locking component 5, as in Figure 2 As shown in the diagram, the first coupler component 21 and the second coupler component 22 can be releasably combined in use, such that the first locking component 6 and the second locking component 5 can be releasably locked in, and the two coupler components 21, 22 are held in each other and a substantially airtight connection is established. To disconnect the coupler, the locking components 5, 6 are released in a predetermined manner, thereby allowing the coupler components 21, 22 to be disconnected. Even when the second coupler component 22 is implemented on a separate coupling adapter that is releasably connected to the probe tip 2, the second locking component 5 can be provided on the second coupler component 22.

[0035] If the detachable connection between the first coupler component 21 and the second coupler component 22 can also be established without locking according to the embodiment of the coupler connection, then the first and second locking components can also be omitted.

[0036] Preferably, the first coupler component 21 is implemented as a concave component connecting the coupler, and the second coupler component 22 is implemented as a convex component connecting the coupler.

[0037] The first coupler component 21 and the second coupler component 22 can be implemented, for example, as a quick-locking coupler, according to ISO 6150B or C, wherein, of course, any other implementation can also be adopted. For example, the connecting coupler (comprising the first coupler component 21 and the second coupler component 22) can also be implemented as a known threaded connection, clamping connection, plug-in connection, bayonet connection, etc., with corresponding implementations having coupler components 21, 22 and locking components 5, 6 as needed.

[0038] In the illustrated embodiment, the coupling is implemented as a quick-locking coupling. The probe tip 2 (in the illustrated embodiment, as a second coupling component 22) is implemented as a coupling plug (convex component), which is inserted into the first coupling component 21, which is implemented as a coupling socket (concave component), to establish a connection. The second coupling component 22 has a second locking component 5 in the form of a circumferential groove 7 on the cylindrical end of the probe tip 2. For locking, a retaining body 8 in the first coupling component 21, such as spheres distributed on the periphery, is engaged into the circumferential groove 7. The retaining body 8 constitutes a first locking component 6. The retaining body 8 can be released or locked in the radial direction by means of an axially movable sliding sleeve 9 on the first coupling component 21. If the retaining body 8 is released by the position of the sliding sleeve 9, the second coupling component 22 can be inserted into or removed from the first coupling component 21. If the retaining body 8 is locked in the radial direction by means of the sliding sleeve 9, the second coupling component 22 is fixed in the first coupling component 21.

[0039] To perform zeroing or calibration / adjustment, exhaust gas probe 1 is connected to the first coupler component 21 of self-test unit 20 via the second coupler component 22. This forms a flow path from gas inlet 23 through self-test line 26 to exhaust gas probe 1 and exhaust gas line 4. Therefore, gas, such as filtered ambient air or calibration / adjustment gas, can be delivered to measurement unit 12 by delivery pump 11 of emission measuring instrument 10 for zeroing or calibration / adjustment. For this purpose, if needed (if present), switchable valve 25 is switched so that the first coupler component 21 is connected to gas inlet 23. This can be done automatically, for example, via control unit 16, by selecting zeroing or calibration / adjustment at the user interface.

[0040] For a leak test, exhaust gas probe 1 is connected to the first coupler component 21 of the self-test unit 20 via the second coupler component 22. The switchable valve 25 is switched so that the first coupler component 21 is not connected to the gas inlet 23. This can be done automatically, for example, via the control unit 16, by selecting to perform a leak test on the user interface. Now, a negative or overpressure can be generated in the connected probe system (exhaust gas probe 1 with exhaust gas line 4) using the delivery pump 11 (depending on the type of pump and its operation). Depending on the arrangement of the delivery pump 11 in the measuring line 14, the leak test of the section of the measuring line 14 upstream of the delivery pump 11 is also checked, and if necessary, the leak test of the components of the emission measuring unit 12 is also checked. After disconnecting the delivery pump 11, the pressure change over time can be checked. It can be specified that the delivery pump 11 is sealed on the outlet side when disconnected, i.e., no pressure rise is generated through the exhaust gas outlet connection 15. This functionality is provided, for example, by a commercially available diaphragm pump.

[0041] Instead of using the delivery pump 11, the negative or overpressure used for sealing checks can also be achieved by connecting the probe system to a preferably external vacuum or overpressure line. For example, compressed air lines are often present in a workshop, and the self-test unit 20 or the emission measuring instrument 10 can be connected to these compressed air lines. In the self-test unit 20, the probe system can therefore be connected to the vacuum or overpressure line via valves and first coupler components 21, 21a. Alternatively, the measuring line 14 in the emission measuring instrument 10 can be connected to such an external vacuum or overpressure line 28 via valve 29, as in... Figure 1a As shown in dashed lines. For example, the first coupler components 21, 21a can preferably be connected to such a vacuum or overpressure line via a valve. Such a valve will therefore also close the ends of the first coupler components 21, 21a to perform a leak test after the probe system is connected to the vacuum or overpressure line and the pressure therein. However, it is also conceivable that there is a line under negative or overpressure in the emission measuring instrument 10 itself. Then, the probe system can also be connected to such a line for performing a leak test.

[0042] For a leak check, a pressure sensor 18 can be installed, for example, in the measuring line 14 of the emission measuring instrument 10, preferably upstream of the delivery pump 11. The control unit 16 can read the pressure sensor 18 at predetermined time steps and evaluate the pressure change over time. If the pressure changes excessively over time (which can be configured in the control unit 16), a leak is determined. For this purpose, a limit value for pressure change over time can be predetermined, and the control unit 16 checks whether the pressure change over time exceeds this limit value within a specific time period. The result of the leak check can be signaled to the user interface 17.

[0043] Instead of the switchable valve 25, it is also conceivable to set two first coupler components 21, 21a on the self-test unit 20, such as in Figure 1a As shown in the diagram, one of them is closed to perform a seal check at the end of the coupling component 21a. Alternatively, the first coupling component 21a can also be connected to an external vacuum or overpressure line via a valve. The other will be connected to the gas inlet 23 via the self-test line 26. Therefore, a switchable valve 25 is not required for switching between seal checks and calibration / adjustment. For the self-test to be performed, the exhaust gas probe 1 must be connected to the correct first coupling components 21, 21a.

[0044] A spacing retainer 27 can also be arranged on the exhaust gas probe 1 in a known manner (such as in...). Figure 4As shown in [the document], so that the exhaust gas probe 1 can be arranged and held, for example, in the end tube of the exhaust gas device. Possible embodiments of the spacing retainer 27 are also described in DE102015108586A1. However, it is also possible (additionally or alternatively) to provide its own holding device for the exhaust gas probe 1 in the end tube, such as as described in WO2015 / 0044256A1.

Claims

1. Emission measuring instruments with self-testing function, among which, An exhaust gas pipeline (4) is connected to the emission measuring instrument (10). The exhaust gas pipeline is connected to the emission measuring unit (12) via the measuring pipeline (14) in the emission measuring instrument (10). An exhaust gas probe (1) for exhaust gas extraction is provided at the end of the exhaust gas pipeline (4) away from the emission measuring instrument (10). The instrument is characterized by having a self-testing unit (20) and a first coupler component (21, 21a) for connecting a coupler is arranged on the self-testing unit (20). A second coupler component (22) for connecting the coupler is arranged on the probe tip (2) of the exhaust gas probe (1). In order to perform self-testing, the second coupler component (22) on the probe tip (2) can be connected to the first coupler component (21, 21a) on the self-testing unit (20). To perform zeroing, adjustment, or calibration, the first coupler component (21) is connected in the self-test unit (20) to the gas inlet (23) of the self-test unit (20) via a self-test line (26), or A self-test line (26) is provided in the self-test unit (20), which connects the first coupler component (21) to the gas inlet (23) on the self-test unit (20). A controllable valve (25) is arranged between the first coupler component (21) and the gas inlet (23) in the self-test unit (20). The valve can close the self-test line (26) to perform a leak check or open the self-test line to perform zeroing, adjustment or calibration, depending on the position of the valve (25).

2. The emission measuring instrument according to claim 1, characterized in that, The probe tip (2) of the exhaust gas probe (1) is implemented as a second coupler component (22).

3. The emission measuring instrument according to claim 1, characterized in that, The second coupler component (22) is detachably disposed on the probe tip (2).

4. The emission measuring instrument according to any one of claims 1 to 3, characterized in that, The self-test unit (20) is integrated into the emission measuring instrument (10).

5. The emission measuring instrument according to any one of claims 1 to 3, characterized in that, A first locking member (6) is provided on the first coupler component (21, 21a), and a second locking member (5) is provided on the second coupler component (22). When the first coupler component (21, 21a) and the second coupler component (22) are connected to each other to manufacture a connecting coupler, the first locking member (6) and the second locking member (5) cooperate to lock the first coupler component (21, 21a) and the second coupler component (22).

6. The emission measuring instrument according to claim 1, characterized in that, To perform a sealing check, the ends of the first coupler components (21, 21a) are closed in the self-test unit (20).

7. The emission measuring instrument according to claim 1, characterized in that, A filter (24) is arranged in the self-test line (26) between the first coupler component (21) and the gas inlet (23).

8. The emission measuring instrument according to claim 1 or 6, characterized in that, A delivery pump (11) is provided in the measuring line (14), and in order to perform a seal check in the probe system consisting of the exhaust gas line (4) and the exhaust gas probe (1), the delivery pump (11) can generate overpressure or negative pressure. A pressure sensor (18) is provided in the measuring line (14), which is connected to the control unit (16) of the emission measuring instrument (10). The control unit (16) evaluates the pressure change over time in the measuring line (14), and when the pressure change over time exceeds a predetermined limit value, the control unit (16) determines that the probe system is not sealed.

9. The emission measuring instrument according to claim 1 or 6, characterized in that, The probe system, consisting of the exhaust gas line (4) and the exhaust gas probe (1), can be connected to a vacuum or overpressure line (28) to perform a seal check. A pressure sensor (18) is provided in the measuring line (14), which is connected to the control unit (16) of the emission measuring instrument (10). The control unit (16) evaluates the time change of pressure in the measuring line (14), and when the pressure change over time exceeds a predetermined limit value, the control unit (16) determines that the probe system is not sealed.

10. The emission measuring instrument according to claim 1, characterized in that, A delivery pump (11) is provided in the measurement line (14), and the delivery pump (11) delivers gas to the emission measurement unit (12) via the gas inlet (23), the self-test line (26), the first coupler component (21), the exhaust gas probe (1) and the exhaust gas line (4) for emission measurement in order to perform zeroing, adjustment or calibration.

11. A method for performing self-testing on an emission measuring instrument (10) with self-testing function, characterized in that, A self-test unit (20) is provided with a first coupler component (21, 21a) having a connecting coupler, and an exhaust gas probe (1) for exhaust gas extraction is provided. The exhaust gas probe is connected via an exhaust gas line (4) to a measuring line (14) in an emission measuring instrument (10) and an emission measuring unit (12) connected to the measuring line. The exhaust gas probe has a probe tip (2), on which the second coupler component (22) having the connecting coupler is arranged. For self-testing, the second coupler component (22) of the probe tip (2) is connected to the first coupler component (21, 21a) on the self-test unit (20). To perform zeroing, adjustment, or calibration, the first coupler component (21) is connected in the self-test unit (20) to the gas inlet (23) of the self-test unit (20) via the self-test line (26), or The self-test line connecting the first coupler component (21) to the gas inlet (23) of the self-test unit (20) can be closed by a controllable valve (25) to perform a leak check or to open the self-test line to perform zeroing, adjustment or calibration.

12. The method according to claim 11, characterized in that, When the first coupler component (21, 21a) and the second coupler component (22) are connected to each other to manufacture a connecting coupler, the first coupler component (21, 21a) and the second coupler component (22) are locked by the first locking component (6) of the first coupler component (21, 21a) and by the second locking component (5) of the second coupler component (22) which cooperates with the first locking component (6).

13. The method according to claim 11 or 12, characterized in that, To perform a sealing check, the ends of the first coupler components (21, 21a) are closed in the self-test unit (20).

14. The method according to claim 11 or 13, characterized in that, An overpressure or negative pressure is generated in the probe system consisting of the exhaust gas line (4) and the exhaust gas probe (1) by a delivery pump (11) in the measuring line (14), and the pressure is measured by a pressure sensor (18) in the measuring line (14), wherein the unsealing of the probe system is identified when the pressure change over time of the measured pressure exceeds a predetermined limit value.

15. The method according to claim 11 or 13, characterized in that, The probe system, consisting of the exhaust gas line (4) and the exhaust gas probe (1) connected to the measuring line (14), is connected to the vacuum or overpressure line (28) to generate overpressure or negative pressure therein, and the pressure is measured using the pressure sensor (18) in the measuring line (14), wherein when the pressure change over time of the measured pressure exceeds a predetermined limit value, the unsealing of the probe system is identified.

16. The method according to claim 11, characterized in that, Gas is delivered to the emission measurement unit (12) via the gas inlet (23), the self-test line (26), the first coupler component (21), the exhaust gas probe (1) and the exhaust gas line (4) for emission measurement in order to perform zeroing, adjustment or calibration using the delivery pump (11) in the measurement line (14).

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