JJF 1873-2020Calibration Specification for Diesel Vehicle Nitrogen Oxides (NOx)Measuring Instruments (English PDF)

1 Scope (1)

2 Reference documents (1)

3 Terms and measurement units (1)

4 Overview (1)

5 Measurement characteristics (2)

5.1 Indication error (2)

5.2 Repeatability of indication (2)

5.3 NO2-NO conversion rate (2)

5.4 Sensor response time (2)

6 Calibration conditions (2)

6.1 Environmental conditions (2)

6.2 Measurement standards and other equipment (3)

7 Calibration items and calibration methods (3)

7.1 Indication error (3)

7.2 Repeatability of indication (3)

7.3 NO2-NO conversion rate (4)

7.4 Sensor response time (5)

8 Calibration result expression (5)

9 Recalibration interval (5)

Appendix A Standard Gas and Its Requirements (6)

Appendix B: Conversion rate calibration method using ozone generator (7)

Appendix C Format of Calibration Certificate (Inner Page) (9)

Appendix D Examples of Uncertainty Evaluation of Measurement Instrument for NO, NO2, CO2 Indication Errors (10)

Introduction

This specification is based on JJF 1071-2010 "Rules for the Compilation of National Metrology and Calibration Specifications", JJF 1001-2011 "General Metrology terms and definitions", JJF 1059.1-2012 "Measuring Uncertainty Evaluation and Expression" are the basic series of specifications Make it:

According to GB 3847-2018 "Diesel vehicle pollutant emission limits and measurement methods (free acceleration method and loading deceleration) Law)", put forward relevant requirements for the detection of nitrogen oxides in diesel vehicle emissions: This specification mainly refers to GB 3847-2018 ``Limits and Measurement Methods of Pollutant Emissions from Diesel Vehicles (Free Acceleration Method and Loading Deceleration Method)'', GB 18285-2018 "Limits and Measurement Methods of Pollutant Emissions from Gasoline Vehicles (Dual Idle Speed Method and Simple Working Condition Method)", JJG688-2017 "Automobile Emission Gas Tester" was compiled:

This specification is released for the first time:

Diesel vehicle nitrogen oxide (NOx) detector Calibration specification

1 Scope

This specification applies to the calibration of nitrogen oxide (NOx) detectors for diesel vehicles:

2 Reference documents this specification refers to the following documents:

JJF 1071-2010 National Metrology and Calibration Specifications Compilation Rules GB 3847-2018 Diesel vehicle pollutant emission limits and measurement methods (free acceleration method and loading deceleration method) GB 18285-2018 Gasoline vehicle pollutant emission limits and measurement methods (dual idle speed method and simple working condition method) for dated reference documents, only the dated version applies to this specification; for undated references the latest version (including all amendments) is applicable to this specification:

3 Terms and units of measurement the following terms and definitions defined in GB 3847-2018 apply to this specification:

3.1 Terms and definitions

3.1.1 NitrogenoxideNOx Nitrogen oxides emitted from exhaust pipes include nitric oxide (NO) and nitrogen dioxide (NO2):

3.1.2 NO2-NO conversion rate convertrateofNO2-NO when NO2 gas passes through the NO2-NO converter, the mole fraction of NO after the reaction is the same as that before the reaction the ratio of the total mole fraction of NO2, expressed as a percentage (%):

3.2 Unit of measurement the nitrogen oxide (NOx) detector for diesel vehicles adopts legal measurement units, of which:

The mole fraction of CO2 is expressed as "%" or "10-2";

The mole fraction of NO and NO2 is represented by "10-6":

4 overview

The detector (hereinafter referred to as the detector) is used to measure the concentration of nitrogen oxides (NOx) in the exhaust pollutants of diesel vehicles:

It is a detection instrument with CO2 concentration monitoring function: According to the measurement method, it is divided into direct measurement of NO and NO2 detection it uses a NO2-NO converter to convert NO2 into NO and then measure it: According to the measurement principle it is a detector that uses chemiluminescence for measurement, a detector that uses ultraviolet sensors for measurement, and a detector that uses infrared sensors:

Detector for measuring:

The detector should have the display function of NOx concentration: Mainly consists of sampling system, pretreatment device, analysis unit, Display device and main control system, etc: