Automobile exhust gas measurement device and method of automobile exhust gas measurement using the same

Abstract

According to one aspect of the present invention, a measuring device for automobile exhaust gas is provided, comprising: a gas inlet through which automobile exhaust gas is introduced; an electronic gas valve connected to the gas inlet; a pump that facilitates the introduction of the automobile exhaust gas; a first measuring cell including a non-dispersive infrared gas sensor; a second measuring cell including a zirconia sensor; and a gas outlet through which the automobile exhaust gas is discharged; wherein an atmospheric inlet through which atmospheric air is introduced is further connected to the electronic gas valve, and the electronic gas valve can selectively allow or block the connection to the exhaust gas inlet and the atmospheric inlet.

Description

Technology Field

[0001] The present invention relates to an automobile exhaust gas measuring device and a method for measuring automobile exhaust gas using the same. Background Technology

[0002] By law, vehicles in operation are required to undergo inspections annually for commercial use and every two years for private use. For gasoline vehicles, the inspection items include measuring the components of exhaust gases; vehicles are permitted to operate only if the emissions of environmentally harmful substances fall below legal regulatory limits. The exhaust gas inspection items include carbon monoxide (CO), hydrocarbons (HC), carbon dioxide (CO2), oxygen (O2), which affects fuel efficiency, and nitrogen oxides (NO2), which have recently emerged as a significant issue. X ...is included. Among these, periodic inspections measure only carbon monoxide (CO), hydrocarbons (HC), and oxygen (O2), while precision inspections measure carbon dioxide (CO2) and nitrogen oxides (NO2) in addition to these. X Measures up to ).

[0003] In most exhaust gas measuring devices currently in use, CO / HC / CO2 are measured using the Non-Dispersive Infrared (NDIR) method, O2 is measured using the electrochemical method, and NOx is measured using either the electrochemical method with a liquid electrolyte or the NDIR method. When measuring exhaust gases using the electrochemical method with a liquid electrolyte, a gas-permeable membrane is used around the sensor. However, if the gas-permeable membrane is covered with moisture, exhaust gases cannot reach the inside of the sensor, leading to measurement errors. Furthermore, in the case of electrochemical sensors, the lifespan is typically one or two years even in favorable environments, and the sensor's lifespan decreases significantly under poor operating conditions. Consequently, there are issues where measurement values ​​for exhaust gases are reduced or measured as zero due to moisture in the vehicle exhaust gas, and where accurate measurements cannot be achieved because the concentration of the corresponding gas is measured as zero when using a sensor that has reached the end of its lifespan. The problem to be solved

[0004] One aspect of the present invention is to provide a measuring device for automobile exhaust gases that has a long lifespan and high accuracy without being affected by moisture.

[0005] Another aspect of the present invention is to provide a method for measuring automobile exhaust gases with high accuracy without being affected by moisture. means of solving the problem

[0006] By one aspect of the present invention

[0007] Gas inlet through which automobile exhaust gas enters;

[0008] Electronic gas valve connected to the above gas inlet;

[0009] A pump that assists in the inflow of the above automobile exhaust gas;

[0010] A first measuring cell including a non-dispersive infrared gas sensor;

[0011] A second measuring cell including a zirconia sensor; and

[0012] The above-mentioned gas outlets through which automobile exhaust gas is emitted are connected in sequence, and

[0013] An atmospheric inlet for introducing air is further connected to the above electronic gas valve, and

[0014] The electronic gas valve above provides a measuring device for automobile exhaust gas that can selectively allow or block connection to the exhaust gas inlet and the atmosphere inlet.

[0015] The first measuring cell above can measure the concentrations of carbon monoxide, hydrocarbons, and carbon dioxide.

[0016] The above second measuring cell can measure the concentrations of nitrogen oxides and oxygen.

[0017] The above second measuring cell is

[0018] The above zirconia sensor;

[0019] A cell housing made of a heat-resistant material surrounding the above-mentioned zirconia sensor;

[0020] A cell inlet and a cell outlet located in opposite directions within the cell housing, through which the automobile exhaust gas enters and exits; and

[0021] It includes a cell space between the zirconia sensor and the cell housing, into which the above automobile exhaust gas is filled.

[0022] The above cell space is 10 cm 3 It may be less than.

[0023] The gap between the zirconia sensor and the cell housing may be 1 cm or less.

[0024] The cell housing above may be made of Teflon (PTFE) or PEEK (polyether ether ketone).

[0025] It further includes a main filter located between the gas inlet and the pump, and the main filter may include a water removal filter for removing water and a dust removal filter for removing dust.

[0026] A zero-point filter between the above-mentioned atmospheric inlet and the above-mentioned pump may be further included.

[0027] A pressure sensor between the main filter and the electronic valve may be further included.

[0028] It further includes a span calibration gas inlet located between the pump and the first measuring cell, and span calibration gas can be introduced from the span calibration gas inlet.

[0029] The temperature in the second measuring cell may be in the range of 0℃ to 100℃.

[0030] The pressure in the second measuring cell may be in the range of 0.5 atmospheres to 2 atmospheres.

[0031] By another aspect of the present invention

[0032] A step of providing the aforementioned automobile exhaust gas measuring device;

[0033] A step of introducing automobile exhaust gas into the automobile exhaust gas measuring device through the above gas inlet;

[0034] A step of measuring the concentrations of carbon monoxide, hydrocarbons, and carbon dioxide in the incoming automobile exhaust gas; and

[0035] A method for measuring automobile exhaust gas is provided, comprising the step of measuring the concentration of nitrogen oxides in the automobile exhaust gas in which the concentrations of hydrocarbons and carbon dioxide are measured.

[0036] The method may further include a step of performing zero-point calibration of the non-dispersive infrared gas sensor for hydrocarbons and carbon dioxide or zero-point calibration of the zirconia sensor for nitrogen oxides using the atmosphere introduced from the atmosphere inlet before the introduction of the automobile exhaust gas.

[0037] The method may further include a step of performing span calibration of the non-dispersive infrared gas sensor for hydrocarbons and carbon dioxide or span calibration of the zirconia sensor for nitrogen oxides using span calibration gas introduced from the span calibration gas inlet before the introduction of the automobile exhaust gas. Effects of the invention

[0038] The automobile exhaust gas measuring device of the present invention uses a zirconia sensor, thereby ensuring that measurement accuracy is not affected by moisture and can be maintained economically without the need for periodic replacement of expensive sensors. Furthermore, the automobile exhaust gas measuring method of the present invention utilizes the said automobile exhaust gas measuring device and, through zero-point calibration and span calibration, enables accurate measurement of automobile exhaust gas without being affected by moisture. Brief explanation of the drawing

[0039] FIG. 1 is a schematic diagram of a nitrogen oxide measuring cell for measuring nitrogen oxides in automobile exhaust gas according to one embodiment. FIG. 2 is a configuration diagram of an automobile exhaust gas measuring device according to one embodiment. FIG. 3 is a flowchart describing the method for measuring nitrogen oxides in automobile exhaust gas according to the present embodiment in sequence. FIG. 4 is a flowchart describing the method for measuring automobile exhaust gas according to one embodiment in sequence. Specific details for implementing the invention

[0040] The terms used in this specification are used merely to describe specific test examples and are not intended to limit the creative concept of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the following, terms such as "comprising" or "having" are intended to indicate the existence of the features, numbers, steps, actions, components, parts, components, materials, or combinations thereof described in the specification, and should be understood as not excluding in advance the existence or addition of one or more other features, numbers, steps, actions, components, parts, components, materials, or combinations thereof.

[0041] In this specification, "CO / HC / CO2" means carbon monoxide (CO), hydrocarbon (HC) and / or carbon dioxide (CO2).

[0042] In this specification, "hydrocarbon" refers to various incomplete combustion compounds composed of carbon and hydrogen.

[0043] The carbon and hydrogen compounds generated at this time produce a wide variety of substances depending on the combustion state, which are collectively treated as hydrocarbon compounds.

[0044] In this specification, "NO X " means nitrogen oxide.

[0045] In this specification, "nitrogen oxide" includes NO, NO2, or N2O.

[0046] In this specification, combustion gas refers to the gas produced as fuel burns in an automobile engine.

[0047] The following describes in detail a nitrogen oxide measuring cell in automobile exhaust gas, an automobile exhaust gas measuring device using the same, and a method for measuring automobile exhaust gas according to embodiments of the present invention.

[0048] (Nitrogen oxide measuring cell)

[0049] FIG. 1 is a schematic diagram of a nitrogen oxide measuring cell (50) for measuring nitrogen oxides in automobile exhaust gas according to one embodiment. Referring to FIG. 1, the nitrogen oxide measuring cell (50) includes a zirconia sensor (51), a cell housing (52), and a cell space (53) filled with a measuring gas (exhaust gas) between the zirconia sensor (51) and the cell housing (52). The cell housing (52) includes a cell inlet (54) for the measuring gas to enter and a cell outlet (55) for the measuring gas to exit, and the cell inlet (54) and the cell outlet (55) may be located diagonally opposite each other. The cell space (53) has a minimum volume for the measuring gas. The cell space (53) may vary depending on the size of the zirconia sensor (51), for example, 10 cm 3The gap (d) between the zirconia sensor (51) and the cell housing (52) may be, for example, 1 cm or less, for example, 0.7 cm or less. The gap (d) may be, for example, 0.1 cm or more, for example, 0.3 cm or more. By minimizing the gap between the zirconia sensor (51) and the cell housing (52) and positioning the inlet (54) and outlet (55) of the measurement cell (50) diagonally, the measurement gas does not remain within the cell space (53). That is, the measurement cell (50) according to the present embodiment has no dead volume inside the cell, and thus the exhaust gas can flow smoothly into and out of the measurement cell (50), and thus the exhaust gas can be well delivered into the zirconia sensor (51).

[0050] The zirconia sensor (51) may be a known zirconia sensor capable of measuring nitrogen oxides. The zirconia sensor is a gas sensor comprising two electrodes and a solid electrolyte between them, wherein the solid electrolyte contains zirconia. The zirconia sensor (51) can measure the concentration of nitrogen oxides such as NO, NO2, and N2O in combination. Additionally, the zirconia sensor (51) can simultaneously measure the concentration of oxygen (O2) along with nitrogen oxides. For example, the zirconia sensor (51) can measure the concentration of oxygen (O2) and nitrogen oxides (NO2). X It may be composed of a dual structure including a zirconia sensor for measuring the concentration of ). The zirconia sensor for measuring the concentration of nitrogen oxides can, for example, decompose nitrogen oxides into nitrogen (N2) and oxygen (O2) by an internal catalyst and measure the concentration of oxygen (O2), and from this, the concentration of nitrogen oxides can be calculated.

[0051] The cell housing (52) is made of a heat-resistant material that is not destroyed or deformed by the high-temperature operation of the zirconia sensor (51). The operating temperature of the zirconia sensor (51) may be in the range of about 700°C to 800°C. The cell housing (52) may be made of a material such as, for example, Teflon (PTFE) or PEEK (polyether ether ketone). Meanwhile, although the zirconia sensor (51) operates at a high temperature, the temperature inside the nitrogen oxide measuring cell (50) may be in the range of 0°C to 100°C. The pressure inside the nitrogen oxide measuring cell (50) may be in the range of about 0.5 to 1.5 atmospheres.

[0052] The nitrogen oxide measuring cell (50) according to the present invention can measure nitrogen oxides at a low cost and with high accuracy without reducing the sensor's measurement sensitivity or lifespan due to temperature by using a zirconia sensor (51). In addition, the nitrogen oxide measuring cell (50) according to the present invention does not have any unusable volume inside the cell, and low-pressure exhaust gas is also quickly delivered into the zirconia sensor (51), thereby increasing the measurement speed and the accuracy of the measurement value.

[0053] Conventional devices for measuring nitrogen oxides in automobile exhaust gases utilize electrochemical gas sensors that employ liquid electrolytes. These liquid electrolyte electrochemical gas sensors include a gas-permeable membrane; however, if this membrane becomes covered by moisture, automobile exhaust gases cannot access the interior of the sensor, leading to inaccurate measurements. In particular, condensation on the membrane occurs frequently during the cold winter months, and since the liquid electrolyte may freeze, slowing down the reaction rate, the sensor may fail to function. Heating the sensor to prevent condensation can shorten its lifespan. Furthermore, even under optimal operating conditions, the lifespan of liquid electrolyte gas sensors is generally short, typically lasting only one or two years.

[0054] On the other hand, zirconia sensors operate at high temperatures of about 70°C or higher, so gas measurement errors caused by moisture do not occur, and their lifespan is over 10 years, which is much longer than that of electrochemical gas sensors using liquid electrolytes. In addition, the response speed of zirconia sensors, that is, the measurement speed, is also shorter than that of electrochemical gas sensors using liquid electrolytes.

[0055] However, zirconia sensors are typically used for combustion gases inside a vehicle, and the measurement environment for external vehicle exhaust gases is significantly different from that for internal combustion gases. Zirconia sensors inside a vehicle are installed before and after the environmental pollutant removal device in the combustion gas path of the engine, and are used to verify the status of pollutant removal or the operation of the removal device. Therefore, zirconia sensors used inside a vehicle are attached close to the engine and come into direct contact with the combustion gases emitted from the engine. Since automobile engines typically have a capacity of several thousand cc and operate at over several hundred rpm, tens of thousands of cc of combustion gases pass through the zirconia sensor per minute, and the pressure of the combustion gases is also considerably high due to the fuel explosion in the engine. Furthermore, because internal zirconia sensors take continuous measurements while the vehicle is in operation, the measurement values ​​are stable.

[0056] On the other hand, in exhaust gas measuring devices outside the vehicle, exhaust gas of about several thousand cc per minute usually passes through the zirconia sensor for a short period of time at atmospheric pressure levels. Therefore, it is difficult to accurately measure the concentration of nitrogen oxides for a short period of time from exhaust gas, which has significantly lower pressure and flow rate (volume per minute) compared to combustion gas, using a zirconia sensor suitable for measuring combustion gas inside the vehicle. To solve this problem, it is necessary to effectively introduce exhaust gas into the zirconia sensor. To this end, the nitrogen oxide measuring cell (50) according to one embodiment is designed so that there is no unusable volume in the cell space (53) inside the measuring cell (50), as described above. As a result, the zirconia sensor can respond with a fast response speed even to low-pressure exhaust gas, and the accuracy of the measurement value can be increased.

[0057] (Vehicle exhaust gas measuring device)

[0058] FIG. 2 is a configuration diagram of an automobile exhaust gas measuring device according to one embodiment. Referring to FIG. 2, the automobile exhaust gas measuring device (100) according to one embodiment has a gas inlet (10), an electronic gas valve (20), a pump (30), a first measuring cell (40), a second measuring cell (50), and a gas outlet (60) connected in order. An air inlet (70) through which air is introduced is further connected to the electronic gas valve (20).

[0059] The gas inlet (10) can be introduced into the exhaust port of a vehicle in the form of a probe so that exhaust gas coming from the exhaust port of the vehicle can be introduced into the vehicle exhaust gas measuring device (100).

[0060] The electronic gas valve (20) can selectively allow or block connection to the gas inlet (10) and the atmosphere inlet (70). The electronic gas valve (20) may be, for example, a solenoid valve.

[0061] A main filter (12) may be located between the gas inlet (10) and the electronic valve (20). The main filter (12) may include a water removal filter (not shown) and / or a dust removal filter (not shown). The water removal filter is connected to a pump (30) to discharge water in the vehicle exhaust gas out of the vehicle exhaust gas measuring device (100) through a water inlet (not shown) and a water outlet (not shown). The vehicle exhaust gas from which water has been removed can have dust and other substances contained in the exhaust gas removed through a dust removal filter.

[0062] A pressure sensor (not shown) may be further included between the main filter (12) and the electronic valve (20). The pressure sensor (not shown) may serve to check whether the vehicle exhaust gas is being properly inhaled.

[0063] The pump (30) helps to lower the pressure inside the vehicle exhaust gas measuring device (100) so that vehicle exhaust gas is sucked in from the gas inlet (10). For example, a diaphragm pump or a peristaltic pump can be used as the pump (30). Meanwhile, the pump (30) can be a double pump and help to discharge water in the exhaust gas as described above.

[0064] The first measuring cell (40) measures the concentration of carbon monoxide (CO), hydrocarbons (HC), and / or carbon dioxide (CO2) in automobile exhaust gas. To this end, the first measuring cell (40) may include, for example, a non-dispersive infrared gas sensor.

[0065] The second measuring cell (50) measures nitrogen oxides (NO₂) of automobile exhaust gas. X The concentrations of ) and oxygen (O2) are measured. To this end, the second measuring cell (50) includes a zirconia gas sensor. The second measuring cell (50) is the same as the nitrogen oxide measuring cell (50) according to the previous embodiment. The contents of the second measuring cell (50) refer to the contents of the nitrogen oxide measuring cell (50) described above.

[0066] Automobile exhaust gas that has passed through the second measuring cell (50) is discharged through the gas outlet (60).

[0067] The air inlet (70) is where air is introduced for zero-point adjustment of the zirconia sensor (51). The automobile exhaust gas measuring device (100) can perform zero-point calibration of the gas sensors in the first measuring cell (40) and the second measuring cell (50) for the component to be measured using the air introduced from the air inlet (70). When performing zero-point calibration, the electronic gas valve (20) blocks the connection to the gas inlet (10) and allows the connection to the air inlet (70). When measuring the concentration of automobile exhaust gas, the electronic gas valve (20) blocks the connection to the air inlet (70) and allows the connection to the gas inlet (10). Zero-point calibration can be performed whenever the concentration of automobile exhaust gas is measured, per a certain number of times the concentration of automobile exhaust gas is measured, or at regular time intervals.

[0068] Gas sensors used inside a vehicle are positioned before and after an environmental pollutant removal device and are used to check the difference in concentration of gas components measured at two locations, so they do not require the measurement of the absolute value of the concentration. However, since the vehicle exhaust gas measuring device (100) must accurately measure the concentration of gas components at one location, zero-point calibration and span calibration of the gas sensor are required. Atmosphere from the atmospheric inlet (70) can be used as the gas for zero-point calibration of the non-dispersive infrared gas sensor in the first measuring cell (40) and the zirconia sensor in the second measuring cell (50). The atmosphere contains nitrogen oxides (NO₂ X It does not contain carbon monoxide (CO), hydrocarbons (HC) and carbon dioxide (CO2), so it can be used as a gas for zero point calibration.

[0069] A zero-point filter (22) may be further included between the air inlet (70) and the electronic valve (20). The zero-point filter (22) is a filter for removing fine dust or highly active gases in the air, as these can affect the measurement. Activated carbon or the like can be used as the zero-point filter (22).

[0070] Meanwhile, the automobile exhaust gas measuring device (100) may further include a span calibration gas inlet (80) for span calibration of a gas sensor between the pump (30) and the first measuring cell (40). The span calibration gas may be a gas for span calibration of a zirconia sensor (51) or a gas for span calibration of a non-dispersive infrared gas sensor (not shown). N2 standard gas may be used as the span calibration gas for measuring nitrogen oxides. Since the non-dispersive infrared gas sensor (not shown) measures the concentrations of CO, HC, and CO2, these gases may be used as span calibration gases. Since CO, HC, and CO2 do not react with each other, they may be mixed in one container and used as span calibration gases.

[0071] Span calibration can be performed at appropriate intervals, for example, once a month or once a week. In order to prevent exhaust gas from leaking out through the span calibration gas inlet (80) when measuring exhaust gas, the span calibration gas inlet (80) may include a check valve (81) that prevents gas from flowing in the opposite direction and allows gas to flow in only one direction, and may optionally include an orifice (not shown).

[0072] The automobile exhaust gas measuring device (100) according to the present embodiment includes the aforementioned nitrogen oxide measuring cell (50) for measuring nitrogen oxides, and further includes a unit for zero point calibration and span calibration, thereby enabling accurate measurement of automobile exhaust gas without being affected by the measurement environment, such as moisture and temperature.

[0073] (Method for measuring nitrogen oxides in automobile exhaust)

[0074] A method for measuring nitrogen oxides in automobile exhaust gas according to another embodiment is described in detail.

[0075] FIG. 3 is a flowchart describing the method for measuring nitrogen oxides in automobile exhaust gas according to the present embodiment in sequence.

[0076] Referring to FIG. 3, a nitrogen oxide measuring cell is prepared (S110). As the nitrogen oxide measuring cell, a nitrogen oxide measuring cell (50) as described in FIG. 1 can be used.

[0077] The zirconia sensor (51) in the measurement cell (50) is zero-calibrated (S120). The step of zero-calibrating the zirconia sensor (51) can be performed using a gas that does not contain nitrogen oxides. For example, the atmosphere can be used as a gas that does not contain nitrogen oxides.

[0078] The zirconia sensor (51) in the measurement cell (50) is span-calibrated (S130). In the step of span-calibrating the zirconia sensor (51), one or more nitrogen oxide standard gases of a constant concentration may be used as span-calibrating gases. For example, span-calibrating may be performed using nitrogen oxide gases of 800 ppm or 1600 ppm, or using both concentrations.

[0079] The concentration of nitrogen oxides in automobile exhaust gas is measured using the above zero-point and span-calibrated zirconia sensor (51) (S140).

[0080] Zero calibration can be performed whenever the nitrogen oxide concentration is measured, or at regular intervals of measurement or time. Span calibration can be performed at longer intervals than zero calibration. For example, span calibration can be performed at intervals of one month or one week. Through zero calibration and span calibration of the zirconia sensor, the accuracy of the nitrogen oxide concentration measurement value can be improved.

[0081] In addition, as described above, the space (53) excluding the zirconia sensor (51) in the nitrogen oxide measuring cell (50) is minimized so that nitrogen oxide introduced into the measuring cell (50) can be quickly transferred into the zirconia sensor (51) and can also escape without remaining in the measuring cell (50), thereby increasing the accuracy of the measurement value.

[0082] (Method for measuring automobile exhaust emissions)

[0083] A method for measuring automobile exhaust gas according to another embodiment is described in detail.

[0084] FIG. 4 is a flowchart describing the method for measuring automobile exhaust gas according to one embodiment in sequence.

[0085] Referring to FIG. 4, a vehicle exhaust gas measuring device is prepared (S210). As a vehicle exhaust gas measuring device, a vehicle exhaust gas measuring device (100) as described in FIG. 2 can be used.

[0086] Automobile exhaust gas is introduced into the automobile exhaust gas measuring device (S220). The automobile exhaust gas can be introduced into the automobile exhaust gas measuring device (100) by inserting the gas inlet (10) into the automobile exhaust port. The gas inlet (10) may be in the form of a probe. A pump (30) may be used to introduce the automobile exhaust gas into the measuring device (100).

[0087] Water and dust are removed from the incoming automobile exhaust gas (S230). At this time, a main filter (12) including a water removal filter and a dust removal filter may be used. A pump may be connected to the water removal filter to help remove water contained in the exhaust gas out of the device. By removing foreign substances such as water and dust from the automobile exhaust gas, the concentration of substances in the exhaust gas can be accurately measured.

[0088] The concentration of CO / HC / CO2 in the vehicle exhaust gas from which water and foreign substances have been removed is measured (S240). For example, the concentration of CO / HC / CO2 can be measured by a non-dispersive infrared sensor. Three non-dispersive infrared sensors for each of CO / HC / CO2 may be located within the first measurement cell (40). As the exhaust gas from which water and foreign substances have been removed passes through the first measurement cell (40), the concentrations of CO / HC / CO2 can be measured simultaneously.

[0089] Next, the concentration of nitrogen oxides in the automobile exhaust gas is measured (S250). As the automobile exhaust gas that has passed through the first measuring cell (40) passes through the second measuring cell (50) containing a zirconia sensor, the concentration of nitrogen oxides can be measured. At this time, the concentration of oxygen can be measured simultaneously.

[0090] The automobile exhaust gas that has passed through the second measuring cell (50) is discharged through the exhaust port (60) (S260).

[0091] Meanwhile, as described above, the method may further include a step of calibrating the zero point of the zirconia sensor and / or the non-dispersive infrared sensor using air. During zero point calibration, the connection from the electronic valve (20) to the air inlet (70) is opened and the connection to the gas inlet (10) is closed. Additionally, as described above, the method may further include a step of performing span calibration using a standard gas connected to the span calibration gas inlet (80). Zero point calibration may be performed whenever the concentration of automobile exhaust gas is measured, or per certain number of automobile exhaust gas concentration measurements, or at regular time intervals. Span calibration may be performed at an appropriate frequency, for example, once a month or once a week. The accuracy of the measured value of the exhaust gas concentration can be improved through zero point calibration and span calibration. Explanation of the symbols

[0092] 10: Gas inlet 12: Main filter 20: Electronic gas valve 22: Zero-point filter 30: Pump 40: First measuring cell 50: Second measuring cell 51: Zirconia sensor 52: Cell housing 53: Cell space 54: Cell Entrance 55: Cell Exit 60: Exhaust port 70: Atmospheric inlet 80: Span calibration gas inlet 81: Check valve 100: Vehicle exhaust gas measuring device

Claims

Claim 1 A measuring device for automobile exhaust gas, comprising: a gas inlet through which automobile exhaust gas is introduced; an electronic gas valve connected to the gas inlet; a pump that assists in the introduction of the automobile exhaust gas; a first measuring cell including a non-dispersive infrared gas sensor; a second measuring cell including a zirconia sensor; and a gas outlet through which the automobile exhaust gas is discharged; wherein an atmospheric inlet through which atmospheric air is introduced is further connected to the electronic gas valve, and the electronic gas valve can selectively allow or block the connection to the gas inlet and the atmospheric inlet. Claim 2 In claim 1, the first measuring cell is a measuring device for automobile exhaust gases that measures the concentrations of carbon monoxide, hydrocarbons, and carbon dioxide. Claim 3 In claim 1, the second measuring cell is a measuring device for automobile exhaust gases that measures the concentrations of nitrogen oxides and oxygen. Claim 4 A measuring device for automobile exhaust gas according to claim 1, wherein the second measuring cell comprises: the zirconia sensor; a cell housing made of a heat-resistant material surrounding the zirconia sensor; a cell inlet and a cell outlet located opposite each other within the cell housing, through which the automobile exhaust gas enters and exits; and a cell space between the zirconia sensor and the cell housing, into which the automobile exhaust gas is filled. Claim 5 In claim 4, the cell space is 10 cm 3 A measuring device for automobile exhaust gases below this level. Claim 6 A measuring device for automobile exhaust gas according to claim 4, wherein the gap between the zirconia sensor and the cell housing is 1 cm or less. Claim 7 In claim 4, the cell housing is a measuring device for automobile exhaust gas made of Teflon (PTFE) or PEEK (polyether ether ketone). Claim 8 A measuring device for automobile exhaust gas according to claim 1, further comprising a main filter located between the gas inlet and the pump, wherein the main filter comprises a water removal filter for removing water and a dust removal filter for removing dust. Claim 9 A measuring device for automobile exhaust gas according to claim 1, further comprising a zero-point filter between the atmosphere inlet and the pump. Claim 10 A measuring device for automobile exhaust gas according to claim 8, further comprising a pressure sensor between the main filter and the electronic gas valve. Claim 11 A measuring device for automobile exhaust gas according to claim 1, further comprising a span calibration gas inlet located between the pump and the first measuring cell, wherein span calibration gas is introduced from the span calibration gas inlet. Claim 12 A measuring device for automobile exhaust gas according to claim 1, wherein the temperature in the second measuring cell is in the range of 0℃ to 100℃. Claim 13 A measuring device for automobile exhaust gas according to claim 1, wherein the pressure in the second measuring cell is in the range of 0.5 atmospheres to 2 atmospheres. Claim 14 A method for measuring automobile exhaust gas comprising: providing an automobile exhaust gas measuring device according to any one of claims 1 to 13; introducing automobile exhaust gas into the automobile exhaust gas measuring device through the gas inlet; measuring the concentrations of carbon monoxide, hydrocarbons, and carbon dioxide in the introduced automobile exhaust gas; and measuring the concentration of nitrogen oxides in the automobile exhaust gas in which the concentrations of hydrocarbons and carbon dioxide have been measured. Claim 15 A method for measuring automobile exhaust gas according to claim 14, further comprising the step of performing zero-point calibration of the non-dispersive infrared gas sensor for hydrocarbons and carbon dioxide or zero-point calibration of the zirconia sensor for nitrogen oxides using the atmosphere introduced from the atmosphere inlet before the automobile exhaust gas is introduced. Claim 16 A method for measuring automobile exhaust gas according to claim 14, further comprising the step of performing span calibration of the non-dispersive infrared gas sensor for hydrocarbons and carbon dioxide or span calibration of the zirconia sensor for nitrogen oxides using a span calibration gas introduced from the span calibration gas inlet before the introduction of the automobile exhaust gas.

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