In-vehicle exhaust gas analysis system, inspection system for in-vehicle exhaust gas analysis system, inspection method for in-vehicle exhaust gas analysis system, and inspection program

Abstract

An in-vehicle exhaust gas analysis system, which is provided with a flowmeter, and an exhaust gas analyzer to analyze a concentration of a measurement target component contained in exhaust gas, includes a standard gas supply mechanism to supply a standard gas containing a predetermined component to the flowmeter and the exhaust gas analyzer. The system is configured to include a detected mass calculation section to calculate a detected mass of a predetermined component by using a flow rate obtained by the flowmeter and a concentration of the predetermined component obtained by the exhaust gas analyzer, a supply mass acquisition section to acquire a supply mass of the predetermined component supplied from the standard gas supply mechanism to the flowmeter and the exhaust gas analyzer, and a mass comparison section to compare a detected mass calculated by the mass calculation section and a supply mass acquired by the supply mass acquisition section.

Claims

1. An inspection system for inspecting an in-vehicle exhaust gas analysis system, the in-vehicle exhaust gas analysis system comprising a flowmeter, including a mounting tube to be externally attached to an exhaust pipe of a vehicle, to measure a flow rate of exhaust gas discharged from the vehicle, and an exhaust gas analyzer to analyze a concentration of a measurement target component contained in the exhaust gas, and the in-vehicle exhaust gas analysis system being configured to be supplied with a standard gas containing a predetermined component, the inspection system comprising: a standard gas supply mechanism including a gas supply port configured to supply the standard gas to the flowmeter and the exhaust gas analyzer, and a gas supply tube configured to supply the standard gas to the mounting tube in a state in which the mounting tube is not attached to the exhaust pipe of the vehicle, wherein the standard gas supply mechanism is configured to permit an inflow of atmospheric air from around the gas supply port into the standard gas supply mechanism such that the standard gas and atmospheric air mix; and one or more processors programmed to calculate a detected mass of the predetermined component by using a flow rate obtained by the flowmeter and a concentration of the predetermined component obtained by the exhaust gas analyzer, acquire a supply mass of the predetermined component supplied to the flowmeter and the exhaust gas analyzer, and compare the detected mass and the supply mass, wherein the predetermined component is a component contained in the exhaust gas.

2. An in-vehicle exhaust gas analysis system comprising: the inspection system for an in-vehicle exhaust gas analysis system according to claim 1; and the flowmeter and the exhaust gas analyzer.

3. The in-vehicle exhaust gas analysis system according to claim 2, wherein the in-vehicle exhaust gas analysis system is configured to supply a mixed gas comprised of the standard gas and atmospheric air to the flowmeter and the exhaust gas analyzer, further comprising: a flow rate control mechanism to control a flow rate of the mixed gas.

4. The in-vehicle exhaust gas analysis system according to claim 3, wherein the flow rate control mechanism is configured to stepwise or continuously change a flow rate of the mixed gas within a measuring range of the flowmeter.

5. The in-vehicle exhaust gas analysis system according to claim 2, wherein the standard gas supply mechanism further comprises a supply-side flow rate control section to control a flow rate of the standard gas supplied to the flowmeter and the exhaust gas analyzer.

6. The in-vehicle exhaust gas analysis system according to claim 2, wherein the one or more processors is further programmed to perform a background correction of the detected mass.

7. An inspection method for an in-vehicle exhaust gas analysis system that includes a flowmeter, including a mounting tube to be externally attached to an exhaust pipe of a vehicle, to measure a flow rate of exhaust gas discharged from the vehicle, and an exhaust gas analyzer to analyze a concentration of a measurement target component contained in the exhaust gas and to be supplied with a standard gas containing a predetermined component that is a component contained in the exhaust gas, the inspection method comprising: supplying a standard gas to the flowmeter and the exhaust gas analyzer via a gas supply port of a standard gas mechanism such that atmospheric air from around the gas supply port is permitted to inflow with the standard gas; supplying the standard gas to the mounting tube in a state in which the mounting tube is not attached to the exhaust pipe of the vehicle via a gas supply tube; calculating a detected mass of the predetermined component supplied to the in-vehicle exhaust gas analysis system by using a flow rate obtained by the flowmeter and a concentration of the predetermined component obtained by the exhaust gas analyzer; acquiring a supply mass of the predetermined component supplied to the in-vehicle exhaust gas analysis system; and comparing the detected mass and the supply mass, wherein the predetermined component is a component contained in the exhaust gas.

8. An in-vehicle exhaust gas analysis system comprising: a flowmeter, including a mounting tube to be externally attached to an exhaust pipe of a vehicle, configured to measure a flow rate of exhaust gas discharged from the vehicle; an exhaust gas analyzer configured to analyze a concentration of a measurement target component contained in the exhaust gas, and to be supplied with a standard gas containing a predetermined component that is a component contained in the exhaust gas; a standard gas supply mechanism including a gas supply port configured to supply the standard gas to the flowmeter and the exhaust gas analyzer, and a gas supply tube configured to supply the standard gas to the mounting tube in a state in which the mounting tube is not attached to the exhaust pipe of the vehicle, wherein the standard gas supply mechanism is configured to permit an inflow of atmospheric air from around the gas supply port; and one or more processors programmed to calculate a detected mass of the predetermined component by using a flow rate obtained by the flowmeter and a concentration of the predetermined component obtained by the exhaust gas analyzer, acquire a supply mass of the predetermined component supplied to the flowmeter and the exhaust gas analyzer, and compare the detected mass and the supply mass.

9. The in-vehicle exhaust gas analysis system according to claim 8, wherein the in-vehicle exhaust gas analysis system is configured to supply a mixed gas comprised of the standard gas and atmospheric air to the flowmeter and the exhaust gas analyzer, further comprising: a flow rate control mechanism to control a flow rate of the mixed gas.

10. The in-vehicle exhaust gas analysis system according to claim 9, wherein the flow rate control mechanism is configured to stepwise or continuously change a flow rate of the mixed gas within a measuring range of the flowmeter.

11. The in-vehicle exhaust gas analysis system according to claim 8, wherein the standard gas supply mechanism further comprises a supply-side flow rate control section to control a flow rate of the standard gas supplied to the flowmeter and the exhaust gas analyzer.

12. The in-vehicle exhaust gas analysis system according to claim 8, wherein the one or more processors is further programmed to perform a background correction of the detected mass.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic diagram that shows a configuration of an in-vehicle exhaust gas analysis system according to the present embodiment;

(2) FIG. 2 is a schematic diagram that shows a configuration of an inspection system in the present embodiment;

(3) FIG. 3 is a schematic diagram that shows a functional configuration of an information processor in the present embodiment; and

(4) FIG. 4 is an inspection flowchart of the in-vehicle exhaust gas analysis system in the present embodiment.

MODE FOR CARRYING OUT THE INVENTION

(5) An embodiment of an inspection system for an in-vehicle exhaust gas analysis system according to the present invention is described below with reference to the drawings.

(6) <In-Vehicle Exhaust Gas Analysis System>

(7) Firstly, the in-vehicle exhaust gas analysis system 10 is described below.

(8) As shown in FIG. 1, the in-vehicle exhaust gas analysis system 10 is one which is mounted in a vehicle V and configured to analyze exhaust gas discharged from an internal combustion engine E of the vehicle when the vehicle V drives on a road, in real time during the driving on the road. The in-vehicle exhaust gas analysis system 10 employs a direct sampling method of directly measuring a concentration of collected exhaust gas without diluting the collected exhaust gas.

(9) The in-vehicle exhaust gas analysis system 10 includes a flowmeter 2 to measure a flow rate of exhaust gas discharged from the vehicle V, and a gas analyzer 3 to analyze a concentration of a measurement target component contained in the exhaust gas.

(10) The flowmeter 2 is attached to an opening end portion EH1 of an exhaust pipe EH being coupled to the internal combustion engine E, and is configured to measure a flow rate of the exhaust gas discharged from the exhaust pipe EH. Specifically, the flowmeter 2 is configured to detect a differential pressure of exhaust gas flowing through a flow channel, and calculate the flow rate of the exhaust gas from the differential pressure. The flowmeter 2 includes a mounting tube externally attached to the opening end portion EH1 of the exhaust pipe EH, a differential pressure detection section 22 to detect a differential pressure of exhaust gas flowing through the mounting tube 21, and a flow rate calculation section 23 to calculate a flow rate of exhaust gas by using the differential pressure obtained by the differential pressure detection section 22.

(11) The mounting tube 21 has a straight pipe-shaped one attached to the opening end portion EH1 of the exhaust pipe EH, and is a circular tube whose cross section is a circular form in the present embodiment. An opening at one end of the mounting tube 21 is attached to the opening end portion EH1 of the exhaust pipe EH, and an opening at the other end is opened. The opening at the other end permits discharge of exhaust gas therethrough to the exterior.

(12) A differential pressure detection section 22 is intended to detect a differential pressure between a total pressure and a static pressure of exhaust gas. The differential pressure detection section 22 includes a pitot tube having a total pressure hole for detecting a total pressure and a static pressure hole for detecting a static pressure, and a differential pressure sensor, such as a differential pressure transmitter, which detects, through the pitot tube, a differential pressure ΔP between the total pressure and the static pressure of the exhaust gas.

(13) The flow rate calculation section 23 calculates a volumetric flow rate Q.sub.exh(t) [m.sup.3/min] of exhaust gas in a standard state according to the following equation and from the differential pressure ΔP obtainable from the differential pressure sensor of the differential pressure detection section 22, an exhaust gas temperature T.sub.exh(t) [K] obtainable from an exhaust gas thermometer (not shown) disposed at the mounting tube 21, and an exhaust gas pressure P.sub.exh(t) [kPa] obtainable from an absolute manometer (not shown) disposed at the mounting tube 21.

(14) $\begin{array}{cc}{Q}_{\mathrm{exh}}\left(t\right)=k\times \sqrt{\frac{P_{\mathrm{exh}}\left(t\right)}{P_0}\times \frac{T_0}{T_{\mathrm{exh}}\left(t\right)}\times \frac{\Delta P}{{\rho }_{\mathrm{exh}}}}& \left[\mathrm{Equation}1\right]\end{array}$

(15) Here, k is a proportionality coefficient, P.sub.0 is a standard pressure (101.3 [kPa]), T.sub.0 is a standard temperature (293.15 [K]), and ρ.sub.exh is an exhaust gas density [g/min.sup.3] in the standard state.

(16) The proportionality coefficient K, standard pressure P.sub.0, standard temperature T.sub.0, and exhaust gas density ρ.sub.exh are previously input.

(17) The gas analyzer 3 is intended to continuously measure a concentration of a measurement target component contained in exhaust gas (for example, CO, CO.sub.2, CO.sub.0, NO.sub.x, and THC). When the gas analyzer 3 is intended to measure the concentration of CO and CO.sub.2, an NDIR detector using non-dispersive infrared absorption method (NDIR method) is usable. When the gas analyzer 3 is intended to measure the concentration of NO.sub.x, a CLD detector using chemiluminescence analysis method (CLD method) is usable. When the gas analyzer 3 is intended to measure the concentration of THC, an FID detector using flame ionization analysis method (FID) is usable. The gas analyzer 3 may include any one of these detectors or a plurality of kinds of these detectors. Alternatively, the gas analyzer 3 may be such a detector that uses different analysis methods according to a measurement target component.

(18) A loading tube 31 for loading sampled exhaust gas is coupled to the gas analyzer 3. One end of the loading tube 31 is coupled to the gas analyzer 3, and a sampling section 32 for sampling exhaust gas is disposed at the other end of the loading tube 31. The sampling section 32 is disposed on the mounting tube 21 of the flowmeter 2 described above. The sampling section 32 is composed of a sampling tube through which part of exhaust gas flowing through the mounting tube 21 is collected.

(19) Concentration signals of individual components obtained by the gas analyzer 3 are transmitted to a host arithmetic unit 4 and used for computing an emission mass of each of the components, together with a flowrate signal outputted from the flow rate calculation section 23 of the differential pressure flowmeter 2.

(20) <Inspection System>

(21) An inspection system 100 is described below.

(22) The inspection system 100 is intended to inspect both the flowmeter 2 and the gas analyzer 3 in the in-vehicle exhaust gas analysis system 10. The in-vehicle exhaust gas analysis system to be inspected by the inspection system 100 may be in a state in which at least the mounting tube 21 of the flowmeter 2 is removed from the exhaust pipe EH of the vehicle V, and the gas analyzer 3 is mounted in the vehicle. The present embodiment describes the inspection system 100 in cases where the gas analyzer 3 is the NDIR detector to measure the concentrations of CO and CO.sub.2.

(23) Specifically, as shown in FIG. 2, the inspection system 100 includes a standard gas supply mechanism 5 to supply a standard gas containing a predetermined component to the in-vehicle exhaust gas analysis system 10, and an information processor 6 to perform information processing for inspecting the accuracy of the in-vehicle exhaust gas analysis system 10.

(24) The standard gas supply mechanism 5 is intended to supply the standard gas having a predetermined flow rate to the in-vehicle exhaust gas analysis system 10. The standard gas supply mechanism 5 includes a standard gas source 51, such as a standard gas cylinder, a standard gas supply tube 52 to supply the standard gas from the standard gas source 51 to the in-vehicle exhaust gas analysis system 10, and a flow rate regulation section 53 to regulate a flow rate of the standard gas supplied to the in-vehicle exhaust gas analysis system 10.

(25) The standard gas source 51 is a CO.sub.2 gas cylinder filled with CO.sub.2 gas in the present embodiment. An opening/closing valve 511a is disposed at a gas supply port 511 of the CO.sub.2 gas cylinder. The opening/closing valve 511a is openable and closable manually or automatically by the information processor 6, or the like.

(26) One end of the standard gas supply tube 52 is coupled to the gas supply port 511 of the CO.sub.2 gas cylinder 51, and the other end thereof is coupled to one end opening of the mounting tube 21 of the flowmeter 2. Here, the one end of the standard gas supply tube 52 is coupled to the gas supply port 511 so as to permit inflow of ambient air (atmospheric air) together with the CO.sub.2 gas. Specifically, the one end opening of the standard gas supply tube 52 is made larger than the gas supply port 511 of the CO.sub.2 gas cylinder 51, thereby permitting the inflow of the atmospheric air from around the gas supply port 511. The standard gas supply tube 52 in the present embodiment is a straight circular tube whose cross section is a circular form, and has approximately the same diameter (approximately the same inner diameter) as the mounting tube 21.

(27) The flow rate regulation section 53 is intended to regulate a flow rate of a mixed gas of the CO.sub.2 gas (standard gas) flowing into the mounting tube 21 of the flowmeter 2 and the atmospheric air so as to reach a predetermined value. Specifically, the flow rate regulation section 53 includes a standard gas discharge tube 531 coupled to the other end opening of the mounting tube 21 of the flowmeter 2, and a flow rate regulating valve 532 and a suction pump 533 which are disposed on the standard gas discharge tube 531.

(28) Similarly to the standard gas supply tube 52, the standard gas discharge tube 531 is a straight circular tube whose cross section is a circular form, and can be made into one which has approximately the same diameter as the mounting tube 21.

(29) The flow rate regulating valve 532 is capable of regulating the flow rate of the standard gas flowing through the mounting tube 21 of the flowmeter 2 so as to reach an arbitrary flow rate, and, for example, an electric-operated valve is usable therefor. The standard gas flowing through the mounting tube 21 of the flowmeter 2 can be made constant by regulating a valve opening degree of the flow rate regulating valve 532 and then sucking the standard gas by the suction pump 533. The valve opening degree of the flow rate regulating valve 532 is controlled by the information processor 6. A rotational speed of the suction pump 533 is also controlled by the information processor 6.

(30) Thus, the mounting tube 21 of the flowmeter 2 in the in-vehicle exhaust gas analysis system 10 is coupled to the standard gas supply tube 52 and the standard gas discharge tube 531, and the standard gas flowing through the mounting tube 21 is regulated by the flow rate regulating valve 532. On this occasion, a flow rate is measured by the flowmeter 2 of the in-vehicle exhaust gas analysis system 10, the standard gas is sampled by the sampling section 32, and a CO.sub.2 concentration in the standard gas is measured by the gas analyzer 3. Signals respectively indicating these values are transmitted to the information processor 6 described below.

(31) The information processor 6 is intended to inspect the accuracy of the in-vehicle exhaust gas analysis system 10 by using the flow rate of the standard gas obtained by the flowmeter 2, and the CO.sub.2 concentration of the standard gas obtained by the gas analyzer 3. The information processor 6 is a so-called computer including, for example, a CPU, memory, and an input/output interface. Alternatively, the information processor 6 may be configured by using the arithmetic unit 4.

(32) Upon execution of an inspection program being stored in the memory, the components of the information processor 6 cooperate with each other to cause the information processor 6 to function as at least a measured flow rate acquisition section 61, a measured concentration acquisition section 62, a detected mass calculation section 63 (background correction section), a supply mass acquisition section 64, and a mass comparison section 65 as shown in FIG. 3.

(33) The measured flow rate acquisition section 61 is intended to acquire a measured flow rate obtained by the flowmeter 2, and acquires the measured flow rate from the flowmeter 2 over a period of time (measuring time) from the beginning of loading of CO.sub.2 from the CO.sub.2 gas cylinder 51 to the termination of the loading. Although the measured flow rate is acquired from the arithmetic unit 4 in the present embodiment, the measured flow rate may be acquired from the flowmeter 2. The measuring time is measured by the information processor 6.

(34) The measured concentration acquisition section 62 is intended to acquire a CO.sub.2 concentration obtained by the gas analyzer 3, and acquires the CO.sub.2 concentration from the gas analyzer 3 over the measuring time. The measured concentration acquisition section 62 acquires a CO.sub.2 concentration of background (hereinafter also referred to as a background concentration) obtained by the gas analyzer 3 in a state in which no standard gas is supplied to the flowmeter 2. Although the measured concentration or background concentration is obtained from the arithmetic unit 4 in the present embodiment, the measured concentration or background concentration may be acquired from the gas analyzer 3.

(35) The detected mass calculation section 63 calculates a detected mass M.sub.mass g [g] of the in-vehicle exhaust gas analysis system 10 by using the measured flow rate G [L] obtained by the measured flow rate acquisition section 61, the CO.sub.2 concentration C.sub.CO2 [vol %] obtained by the measured concentration acquisition section 62, and the background concentration C.sub.amb [vol %] obtained by the measured concentration acquisition section 62. Specifically, the detected mass calculation section 63 integrates the detected mass M.sub.mass [g] in the measuring time from the following equation in which ρ is a gas density [g/L] of CO.sub.2.
M.sub.mass=∫(ρ×Q×(C.sub.co2−C.sub.amb))dt  [Equation 2]

(36) The supply mass acquisition section 64 is intended to acquire a CO.sub.2 mass (supply mass) supplied to the in-vehicle exhaust gas analysis system 10 by the standard gas supply mechanism 5. Specifically, the supply mass acquisition section 64 acquires a difference between a cylinder mass W.sub.1 [g] of the CO.sub.2 gas cylinder 51 before supplying CO.sub.2 and a cylinder mass W.sub.2 [g] after supplying CO.sub.2 (W=W.sub.1−W.sub.2). The supply mass W [g] is obtainable by measuring a weight of the CO.sub.2 gas cylinder 51 by an operator. Alternatively, the supply mass acquisition section 64 may calculate the supply mass W [g] by causing the supply mass acquisition section 64 to acquire data indicating the cylinder mass W.sub.1 [g] before supplying CO.sub.2 and the cylinder mass W.sub.2 [g] after supplying CO.sub.2.

(37) The mass comparison section 65 is intended to calculate a relative error Err [%] of the detected mass M.sub.mass [g] relative to the supply mass W [g] by comparing the detected mass M.sub.mass [g] obtained by the detected mass calculation section 63, and the supply mass W [g] obtained by the supply mass acquisition section 64. Specifically, the mass comparison section 65 calculates the relative error Err [%] from the following equation.

(38) $\begin{array}{cc}\mathrm{Err}=\left(\frac{M_{\mathrm{mass}}}{W}-1\right)\times 100& \left[\mathrm{Equation}3\right]\end{array}$

(39) An embodiment of an inspection procedure of the in-vehicle exhaust gas analysis system 10 is described below with reference to FIG. 4.

(40) Firstly, the in-vehicle exhaust analysis system 10 is attached to the inspection system 100 (step S1). Specifically, the standard gas supply tube 52 and the standard gas discharge tube 531 are coupled to the mounting tube 21 of the flowmeter 2.

(41) Subsequently, atmospheric air having a predetermined flow rate is supplied to the in-vehicle exhaust gas analysis system 10 by the flow rate regulating valve 532 and the suction pump 533 in the flow rate regulation section 53, without supplying CO.sub.2 from the CO.sub.2 gas cylinder 51. On this occasion, the gas analyzer 3 samples atmospheric air and measures a CO.sub.2 concentration in the atmospheric air (a background concentration) (step S2). The background concentration is transmitted to the measured concentration acquisition section 62 of the information processor 6. The measurement of the background concentration may be carried out after the following measurement of a CO.sub.2 concentration with the use of the standard gas (step S3).

(42) Subsequently, CO.sub.2 is supplied from the CO.sub.2 gas cylinder 51, and standard gas having a predetermined flow rate is supplied to the in-vehicle exhaust gas analysis system 10 by the flow rate regulating valve 532 and the suction pump 533 in the flow rate regulation section 53. On this occasion, the flowmeter 2 measures a flow rate of the standard gas, and the gas analyzer 3 measures a CO.sub.2 concentration of the standard gas (step S3). The flow rate of the standard gas is transmitted to the measured flow rate acquisition section 61, and the CO.sub.2 concentration in the standard gas is transmitted to the measured concentration acquisition section 62.

(43) The measuring time is approximately five minutes. During the measuring time, the flow rate may be made constant, or the flow rate may be changed stepwise or continuously within the flow rate range of the flowmeter 2.

(44) Then, the detected mass calculation section 63 calculates a detected mass by using the obtained background concentration, the obtained flow rate of the standard gas, and the obtained CO.sub.2 concentration of the standard gas (step S4).

(45) The operator calculates a supply mass by measuring each of a mass of the CO.sub.2 gas cylinder 51 before and after loading CO.sub.2, and then inputs the supply mass to the information processor 6 with the use of input means (not shown) (step S5).

(46) The mass comparison section 65 of the information processor 6 calculates a relative error by comparing the detected mass obtained by the detected mass calculation section 63 and the supply mass obtained by the supply mass acquisition section 64 (step S6). The calculated relative error is displayed on a display of the information processor 6. Alternatively, when the relative error is a predetermined threshold value or more (for example, ±2% or more), a determination may be made that this is a system error, and an error indication or the like may be performed.

Effects of Present Embodiment

(47) With the inspection system 100 for the in-vehicle exhaust gas analysis system 10 according to the present embodiment so configured, the comparison is made between the detected mass calculated from the flow rate of the standard gas obtained by the flowmeter 2 and the concentration of the predetermined component obtained by the gas analyzer 3, and the supply mass of the predetermined component supplied to the in-vehicle exhaust gas analysis system 10. Therefore, the in-vehicle exhaust gas analysis system 10 is simply inspectable without the use of the CVS that has been used conventionally. Because there is no need to use the CVS, it is possible to eliminate the need for the preparation work for operating the chassis dynamometer and the work for carrying the in-vehicle exhaust gas analysis system 10 that has been mounted in the actual vehicle into the test room in which the CVS is disposed.

Other Embodiments

(48) The present invention is not limited to the above embodiment.

(49) For example, the flow rate is regulated by the flow rate regulating valve 532 and the suction pump 522 disposed on the standard gas discharge tube 531 in the present embodiment. Alternatively, the flow rate or CO.sub.2 concentration of the standard gas supplied to the in-vehicle exhaust gas analysis system 10 may be regulated by disposing a supply-side flow rate regulation section, for example, by disposing a flow regulating value on the standard gas supply tube 52, or by disposing a flow rate regulating valve at the gas supply port 511 of the CO.sub.2 gas cylinder 51.

(50) By regulating the amount of supply of CO.sub.2 from the CO.sub.2 gas cylinder 51 with the use of a supply regulating part, such as a valve, and also by regulating the flow rate of the standard gas with the use of the flow rate regulation section 53, the flow rate and concentration of the standard gas supplied to the mounting tube 21 of the flowmeter 2 can be changed into a variety of combinations, such as a large flow rate and a low CO.sub.2 concentration, a large flow rate and a high CO.sub.2 concentration, a small flow rate and a high CO.sub.2 concentration, and a small flow rate and a low CO.sub.2 concentration.

(51) When the in-vehicle exhaust gas analysis system 10 is inspected a plurality of times by the inspection system 100 of the above embodiment, the flow rates of the standard gas flown through in the inspections may differ from each other. In this case, it is also possible to focus on the inspection of the flowmeter 2 by being changed into a plurality of points within the measuring range of the flowmeter 2.

(52) Although the CO.sub.2 gas is used as the predetermined component of the standard gas in the inspection in the present embodiment, besides that, a predetermined component contained in the standard gas is selectable according to a detector of the gas analyzer 3.

(53) In the above embodiment, the detected mass calculation section is intended to perform the background correction. Alternatively, a background correction section may be included separately, and the background correction section may subtract a background concentration from a concentration of a predetermined component obtained by the gas analyzer 3. In this case, the detected mass calculation section calculates a detected mass by using a predetermined component concentration corrected by the background correction section.

(54) A mixing section, such as an orifice, may be disposed at the one end opening of the mounting tube 21 or in the vicinity thereof in order to make uniform the mixed gas of the standard gas supplied to the mounting tube 21 and atmospheric air.

(55) Although the standard gas supply mechanism 5 in the present embodiment has the standard gas supply tube 52, the standard gas may be directly supplied from the gas supply port 511 of the standard gas source 51 to the one end opening of the mounting tube 21 instead of including the standard gas supply tube 52.

(56) Moreover, the in-vehicle exhaust gas analysis system may be one which has the inspection function of the above embodiment. Specifically, the arithmetic unit 4 of the in-vehicle exhaust gas analysis system may be one which has, for example, the detected mass calculation section, the supply mass acquisition section, and the mass comparison section. Here, the in-vehicle exhaust gas analysis system may further include the standard gas supply mechanism of the above embodiment.

(57) Furthermore, the information processor 6 is intended to calculate the detected mass by acquiring the measured flow rate and the measured concentration in the above embodiment. The information processor 6 may include the detected mass acquisition section to acquire a detected mass insofar as the detected mass is calculated by an external unit, for example, insofar as the arithmetic unit 4 of the in-vehicle exhaust gas analysis system 10 calculates the detected mass.

(58) Although the exhaust gas analysis system of the above embodiment is configured to be mounted in the vehicle, the system may be a stationary one without being mounted on the vehicle, insofar as the configuration of each of the flowmeter and the exhaust gas analyzer remains identical or similar. Even in this case, the inspection is performable by applying a method similar to that in the above embodiment.

(59) Although the exhaust gas analyzer is intended to measure the concentration of the measurement target component in the above embodiment, the exhaust gas analyzer may be configured to analyze the number of particles contained in exhaust gas or the mass of the particles. Even in this case, the inspection is performable by applying the method of the above embodiment.

(60) Besides the above, it will be understood that the present invention is not limited to the above-described embodiment, and various modifications may be made without departing from the spirit and scope of the present invention.

DESCRIPTION OF THE REFERENCE NUMERAL

(61) 100 inspection system V vehicle EH exhaust pipe 10 in-vehicle exhaust gas analysis system 21 mounting tube 2 flowmeter 3 exhaust gas analyzer 5 standard gas supply mechanism 52 standard gas supply tube 53 flow rate regulation section 532 flow rate regulating valve 533 suction pump 63 detected mass calculation section 64 supply mass acquisition section 65 mass comparison section