A system for detecting pollutants emitted from a vehicle carbon canister
By using a loop consisting of a miniature sealed chamber, a hydrogen flame ionization detector, and a Fourier transform infrared spectrometer, the problem of low accuracy in existing carbon canister emission testing has been solved, enabling precise quantitative detection of pollutant emissions from methanol fuel vehicles and improving testing reliability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA AUTOMOTIVE ENG RES INST
- Filing Date
- 2026-03-23
- Publication Date
- 2026-05-29
AI Technical Summary
Existing methods for testing emissions from charcoal canisters cannot accurately detect pollutant emissions from methanol-fueled vehicles, especially under low evaporation emission conditions, where the testing accuracy is low and pollutant concentrations cannot be directly obtained.
A loop circuit consisting of a miniature sealed chamber, a hydrogen flame ionization detector, and a Fourier transform infrared spectrometer is used to collect and calculate the emissions from the carbon canister through a controller. Combined with the data from the hydrogen flame ionization detector and the Fourier transform infrared spectrometer, accurate quantitative detection of pollutants from methanol fuel vehicles is achieved.
This improved the reliability of charcoal canister escaping tests, enabling direct and accurate quantitative detection of pollutant emissions from methanol-fueled vehicles and solving the problem of low test accuracy.
Smart Images
Figure CN122109273A_ABST
Abstract
Description
Technical Field
[0001] The embodiments in this specification pertain to the field of automotive emission pollutant detection, and specifically relate to a system for detecting pollutants emitted from automotive charcoal canisters. Background Technology
[0002] Compared to traditional gasoline, methanol-fueled vehicles produce significantly lower pollutant emissions in their exhaust, leading to the rapid development of the methanol vehicle industry. However, methanol fuel is prone to problems in terms of evaporative pollutant emissions, such as fuel vapor escaping through the sealing material itself, forming unconventional evaporative emission pathways, and the smaller size and higher polarity of the molecules causing a decrease in the adsorption efficiency of the charcoal canister for methanol vapor.
[0003] Canister evaporation emissions testing detects evaporative pollutants generated by the vehicle's fuel system and ultimately released into the external environment through the canister's vent during diurnal temperature variations. Current canister evaporation emissions testing typically uses a collection method to obtain a certain volume of sample gas, followed by offline analysis of methanol concentration using gas chromatography. This method requires a large sampling flow rate, making it unsuitable for testing the relatively low evaporative emissions from the canister's vent. It also results in low accuracy, and the offline analysis method cannot directly obtain pollutant concentrations, leading to unsatisfactory test results. Summary of the Invention
[0004] Embodiments of this disclosure provide a pollutant detection system for emissions from automotive charcoal canisters, designed to address one or more of the aforementioned problems and other potential issues.
[0005] According to a first aspect of this disclosure, a pollutant detection system for emissions from automotive charcoal canisters is provided. The system includes a miniature sealed chamber, a hydrogen flame ionization detector, a Fourier transform infrared spectrometer, and a controller. The miniature sealed chamber, the hydrogen flame ionization detector, and the Fourier transform infrared spectrometer are sequentially connected to form a loop. The controller is electrically connected to the miniature sealed chamber, the hydrogen flame ionization detector, and the Fourier transform infrared spectrometer. The controller is configured to respond to a test command by acquiring first test data at an initial moment corresponding to the test command. The first test data includes a first temperature and a first pressure of the miniature sealed chamber, a first hydrocarbon pollutant concentration of the hydrogen flame ionization detector, and a first methanol concentration of the Fourier transform infrared spectrometer. The controller is also configured to acquire second test data at a first moment after a first preset time elapsed from the initial moment. The second test data includes a second temperature and a second pressure of the miniature sealed chamber, a second hydrocarbon pollutant concentration of the hydrogen flame ionization detector, and a second methanol concentration of the Fourier transform infrared spectrometer. The controller is further configured to calculate the charcoal canister emission amount at the first moment based on the first and second test data.
[0006] The solution provided in the embodiments of this specification can solve the problem of inaccurate response of the hydrogen flame ionization detector to methanol and inability to distinguish between alcohol and hydrocarbon emissions by introducing the sampled gas in the miniature sealed chamber into the hydrogen flame ionization detector and the Fourier transform infrared spectrometer respectively, and then returning the gas to the miniature sealed chamber. This enables accurate quantitative detection of pollutant emissions from methanol fuel vehicles directly during the canister escaping test, thus improving the reliability of the canister escaping test. Attached Figure Description
[0007] The above and other features, advantages, and aspects of the embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description. In the drawings, the same or similar reference numerals denote the same or similar elements, wherein:
[0008] Figure 1 A schematic diagram of the architecture of a pollutant detection system for vehicle charcoal canister emissions according to some embodiments of the present disclosure is shown. Detailed Implementation
[0009] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.
[0010] The terms “comprising” and “having”, and any variations thereof, in this specification, claims, and the foregoing drawings are intended to cover a non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus. Depending on the context, the word “if” as it applies herein may be interpreted as “when”, “in response to determination”, or “in response to detection”.
[0011] Figure 1A schematic diagram of the architecture of a vehicle charcoal canister emission pollutant detection system 100 according to some embodiments of the present disclosure is shown. System 100 includes a miniature sealed chamber 110, a flame ionization detector (FID) 120, a Fourier transform infrared spectrometer (FTIR) 130, and a controller 140. The miniature sealed chamber 110, the flame ionization detector 120, and the FTIR spectrometer 130 are sequentially connected to form a loop. The controller 140 is electrically connected to the miniature sealed chamber 110, the flame ionization detector 120, and the FTIR spectrometer 130.
[0012] The controller 140 is configured to respond to a test command and acquire first test data at the initial moment corresponding to the test command. The first test data includes the first temperature and first pressure of the micro-sealed chamber 110, the first hydrocarbon contaminant concentration of the hydrogen flame ionization detector 120, and the first methanol concentration of the Fourier transform infrared spectrometer 130.
[0013] The controller 140 is also configured to collect second test data at a first moment after a first preset time elapsed from the initial moment. The second test data includes the second temperature and second pressure of the miniature sealed chamber 110, the second hydrocarbon pollutant concentration of the hydrogen flame ionization detector 120, and the second methanol concentration of the Fourier transform infrared spectrometer 130.
[0014] The controller 140 is also configured to calculate the amount of carbon canister emissions at the first moment based on the first test data and the second test data.
[0015] In this embodiment, the controller 140 may include, but is not limited to, mobile phones, tablets, desktop computers, servers, etc. A miniature sealed chamber is a small, robust space used in industrial testing that can be physically isolated from (or controllably connected to) the external environment while maintaining specific internal environmental parameters; examples include sealing test chambers, pressure test chambers, and environmental aging test chambers. After the operator adjusts and sets up the test environment for the vehicle's fuel system, the atmospheric port of the fuel system's charcoal canister can be connected to the miniature sealed chamber. By opening the miniature sealed chamber or running a scavenging pump, the interior and connecting pipes are purged, allowing contaminants to enter the miniature sealed chamber until the background contaminants stabilize. Simultaneously, the environmental chamber (or vehicle-level sealed chamber) containing the system of this application is run for day and night temperature cycling, and then the miniature sealed chamber is closed and sealed. After completing the above preparations, the operator can send test commands to the controller via their own mobile phone, tablet, or other terminal to instruct the controller to perform the test procedure. At the initial moment of the test (within the first 10 minutes if error needs to be considered), the controller can collect the initial temperature and initial pressure inside the miniature sealed chamber using temperature and pressure sensors, respectively, and record them as follows: , The units are respectively and The concentration of the first hydrocarbon pollutant in FID is denoted as The unit is ppm (volume) C1 equivalent, the first methanol concentration of FTIR, denoted as The unit is ppm (volume) C1 equivalent. Then, after a first preset time (e.g., one day and night, i.e., 24 hours; if error needs to be considered, then...) at the initial time... The second temperature reading of the miniature sealed chamber will be collected again immediately afterward. Second pressure The concentration of second hydrocarbon pollutants in a miniature sealed chamber, detected by a hydrogen flame ionization detector and a Fourier transform infrared spectrometer. Second methanol concentration Based on the first and second test data, the emissions from the charcoal canister at the first moment can be calculated as follows:
[0016]
[0017] in, The mass of hydrocarbons discharged from the fixed-volume micro-sealed chamber during a carbon canister effluent emission test. The mass of hydrocarbons entering the micro-chamber with constant volume during the carbon canister effluent emission test. Net volume of a miniature sealed chamber; for ; The carbon-hydrogen ratio is typically taken as 2.33. The response coefficient of the FID detector to methanol can be represented by the recommended value of 0.63, or it can be obtained through actual measurement. For calibration temperature; For calibration pressure.
[0018] In one possible implementation, the controller is further configured to collect third test data at a second time after a second preset time elapsed from the initial time, and calculate the amount of carbon canister emissions at the second time based on the first test data and the third test data. The third test data includes the third temperature and third pressure of the micro-sealed chamber, the third hydrocarbon pollutant concentration of the hydrogen flame ionization detector, and the third methanol concentration of the Fourier transform infrared spectrometer. The second preset time is longer than the first preset time.
[0019] In this embodiment, in order to further evaluate the emissions from the charcoal canister, in addition to collecting second test data for calculation after a first preset time period (e.g., 24 hours), a third test data can also be collected at a second moment after a second preset time period (e.g., 48 hours), that is, the third temperature of the micro-sealed chamber at the third moment. Third pressure Concentration of third hydrocarbon pollutants in a miniature sealed chamber, detected by a hydrogen flame ionization detector and Fourier transform infrared spectroscopy. and third methanol concentration Based on the first and third test data, the emissions from the charcoal canister at the second time point can be calculated as follows:
[0020]
[0021] In one possible implementation, the controller is further configured to send a first instruction message to a preset terminal before acquiring the second and third test data. The first instruction message is used to instruct the staff to calibrate the zero point and measurement point of the hydrogen flame ionization detector and the Fourier transform infrared spectrometer.
[0022] In this embodiment, before each sampling of test data, the controller sends a first instruction message to the preset terminal used by the operator, reminding them to recalibrate the zero point and measurement point of the flame ionization detector and the Fourier transform infrared spectrometer. As an example, the flame ionization detector and the Fourier transform infrared spectrometer can be equipped with multi-port valves or calibration gas switching valves. When calibration is required, the gas source of the instrument can be switched from the miniature sealed chamber to the calibration gas pipeline. For zero-point calibration, the switch is made to a high-purity zero gas (such as nitrogen, hydrogen, and air) cylinder or generator, while for measurement point calibration, the switch is made to a measurement gas cylinder of known concentration (such as a propane and air mixer). After calibration, the valve is switched back to the pipeline corresponding to the miniature sealed chamber, allowing continued detection of the gas within the miniature sealed chamber.
[0023] In one possible implementation, the controller is also configured to send a second instruction message to a preset terminal, the second instruction message being used to instruct the operator to perform preprocessing on the system under test, the preprocessing including oil change, vehicle soaking, carbon canister desorption, and carbon canister gas loading.
[0024] In this embodiment, the controller also sends a second instruction to a preset terminal used by the operator to remind them to pre-treat the system under test, i.e., the fuel system of the vehicle under test, before starting the test. As an example, pre-treatment may include oil change, vehicle immersion, charcoal canister desorption, and charcoal canister gas loading. Oil change involves adding fuel to the tank at a certain proportion of its nominal volume; this process requires temperature control. Vehicle immersion involves placing the fuel system in an immersion area at a specific ambient temperature for a prescribed period. Charcoal canister desorption involves fixing the vehicle under test on a chassis dynamometer with an environmental simulation chamber and operating it under prescribed test conditions, or desorbing the charcoal canister through an equivalent method. Charcoal canister gas loading involves using… A mixture of butane and nitrogen in a specific volume ratio is used to load the carbon canister according to the specified butane flow rate. During this period, the auxiliary carbon canister is continuously weighed. When the test carbon canister reaches the critical point, the gas supply of butane and nitrogen is immediately shut off.
[0025] In one possible implementation, the outlet of the hydrogen flame ionization detector is connected to the inlet of the Fourier transform infrared spectrometer, and the inlet of the hydrogen flame ionization detector and the outlet of the Fourier transform infrared spectrometer are respectively connected to a miniature sealed chamber.
[0026] In this embodiment, by controlling the pump, it can be ensured that after the gas in the miniature sealed chamber enters the hydrogen flame ionization detector, it flows from its outlet into the Fourier transform infrared spectrometer, and finally flows back from the outlet of the Fourier transform infrared spectrometer to the miniature sealed chamber, realizing the unidirectional closed-loop flow of the gas. This achieves the detection of the gas concentration in the miniature sealed chamber while avoiding abnormal loss of gas concentration in the miniature sealed chamber during the detection process.
[0027] In one possible implementation, the piping between the miniature sealed chamber and the hydrogen flame ionization detector, between the miniature sealed chamber and the Fourier transform infrared spectrometer, and between the hydrogen flame ionization detector and the Fourier transform infrared spectrometer are all low-permeability piping.
[0028] In this embodiment, to prevent additional gas escape during the detection process, low-permeability tubing should be used. Low-permeability tubing requires extremely low permeability of its walls to gases (especially small molecules and VOCs) to prevent ambient air components (such as oxygen and water vapor) from seeping into the tubing and contaminating the sample, or to prevent gases in the sample from permeating through the tubing walls and causing additional losses. Specifically, low-permeability tubing can be made of metal (such as stainless steel or nickel-based alloys) or special polymers (such as polyetheretherketone or polytetrafluoroethylene). Furthermore, in this system, the length of the low-permeability tubing should not exceed 5 meters, the inner diameter should not exceed 8 millimeters, and it should be kept warm using heating or insulation devices.
[0029] Although the subject matter has been described using language specific to structural features and / or methodological logic, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or actions described above. Rather, the specific features and actions described above are merely illustrative examples of implementing the claims.
Claims
1. A system for detecting pollutants emitted from automotive charcoal canisters, characterized in that, The system includes a miniature sealed chamber, a hydrogen flame ionization detector, a Fourier transform infrared spectrometer, and a controller. The miniature sealed chamber, the hydrogen flame ionization detector, and the Fourier transform infrared spectrometer are connected in sequence to form a loop. The controller is electrically connected to the miniature sealed chamber, the hydrogen flame ionization detector, and the Fourier transform infrared spectrometer respectively. The controller is configured to respond to a test command and acquire first test data at the initial moment corresponding to the test command. The first test data includes the first temperature and first pressure of the micro-sealed chamber, the first hydrocarbon contaminant concentration of the hydrogen flame ionization detector, and the first methanol concentration of the Fourier transform infrared spectrometer. The controller is also configured to collect second test data at a first moment after a first preset time elapsed from the initial moment. The second test data includes the second temperature and second pressure of the micro-sealed chamber, the second hydrocarbon pollutant concentration of the hydrogen flame ionization detector, and the second methanol concentration of the Fourier transform infrared spectrometer. The controller is also configured to calculate the amount of carbon canister emissions at the first time point based on the first test data and the second test data.
2. The pollutant detection system for automobile charcoal canister emissions according to claim 1, characterized in that, The controller is also configured to collect third test data at a second time after a second preset time elapsed from the initial time, and to calculate the amount of carbon canister emissions at the second time based on the first test data and the third test data. The third test data includes the third temperature and third pressure of the micro-sealed chamber, the third hydrocarbon pollutant concentration of the hydrogen flame ionization detector, and the third methanol concentration of the Fourier transform infrared spectrometer. The second preset time is longer than the first preset time.
3. The pollutant detection system for automobile charcoal canister emissions according to claim 2, characterized in that, The controller is also configured to send a first instruction message to a preset terminal before collecting the second and third test data. The first instruction message is used to instruct the staff to calibrate the zero point and measurement point of the hydrogen flame ionization detector and the Fourier transform infrared spectrometer.
4. The pollutant detection system for automobile charcoal canister emissions according to claim 2, characterized in that, The first preset duration is 24 hours, and the second preset duration is 48 hours.
5. The pollutant detection system for emissions from automotive charcoal canisters according to claim 1, characterized in that, The controller is also configured to send a second instruction message to a preset terminal, the second instruction message being used to instruct the staff to perform preprocessing on the system under test, the preprocessing including oil change, vehicle immersion, carbon canister desorption, and carbon canister gas loading.
6. The pollutant detection system for emissions from automotive charcoal canisters according to claim 1, characterized in that, The outlet of the hydrogen flame ionization detector is connected to the inlet of the Fourier transform infrared spectrometer, and the inlet of the hydrogen flame ionization detector and the outlet of the Fourier transform infrared spectrometer are respectively connected to a miniature sealed chamber.
7. The pollutant detection system for automobile charcoal canister emissions according to claim 1, characterized in that, The piping between the miniature sealed chamber and the hydrogen flame ionization detector, between the miniature sealed chamber and the Fourier transform infrared spectrometer, and between the hydrogen flame ionization detector and the Fourier transform infrared spectrometer are all low-permeability piping.
8. The pollutant detection system for automobile charcoal canister emissions according to claim 7, characterized in that, The length of the low-permeability pipeline shall not exceed 5 meters, and the inner diameter shall not exceed 8 millimeters.