Pm sensor smoke sensing device based on air-fuel ratio control

Abstract

The utility model relates to PM sensor test technical field, concretely, it relates to PM sensor smoke test device based on air -fuel ratio control. It includes power supply module, particulate matter generation module and PM sensor module. The utility model carries out voltage distribution to different sensor required operating voltage through power supply module, and particulate matter generation module monitors the concentration of oxygen in mixed gas in real time, and through the air -controlled gas valve control air intake total amount and the amount of exhaust gas mixed into the air, so that the kerosene in the diesel heater does not burn completely and produces particulate matter, and the PM sensor module detects the time when the current reaches the preset threshold, judges the concentration of particulate matter in the tail gas, realizes the real -time regulation and control of the air -fuel ratio according to the content of oxygen concentration in the mixed gas, and further accurately controls the generation amount of particulate matter, lays the foundation for the subsequent PM sensor test, and circulates and utilizes the waste gas, reduces energy consumption.

Description

Technical Field

[0001] This utility model relates to the field of PM sensor testing technology, and more specifically, to a PM sensor smoke detection testing device based on air-fuel ratio control. Background Technology

[0002] With increasingly stringent environmental protection requirements, PM sensors are being used more and more widely in fields such as vehicle exhaust emission monitoring. The performance of PM sensors directly affects the accuracy of particulate matter concentration monitoring, so precise testing of PM sensors is necessary.

[0003] Currently, traditional PM sensor smoke detection devices simply reduce the amount of air entering the system, lacking a real-time feedback mechanism. They are easily affected by factors such as ambient air pressure and pipe resistance, resulting in large fluctuations and poor stability in particulate matter concentration. Furthermore, they cannot recycle exhaust gas, leading to energy waste. In order to control the air-fuel ratio by controlling the total amount of air entering the system and the amount of exhaust gas mixed into the intake air, and to provide feedback for air-fuel ratio control based on the oxygen concentration in the mixed gas, thereby generating stable particulate matter and improving the accuracy of PM sensor smoke detection while reducing energy consumption, we propose a PM sensor smoke detection device based on air-fuel ratio control. Utility Model Content

[0004] The purpose of this invention is to provide a PM sensor smoke detection testing device based on air-fuel ratio control, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, this utility model provides a PM sensor smoke detection testing device based on air-fuel ratio control, including a power supply module, a particulate matter generation module, and a PM sensor module, wherein the PM sensor module includes a testing unit and a display unit.

[0006] The power supply module uses a multi-voltage output circuit to distribute voltages according to the operating voltage required by different sensors, maintaining the normal operation of the sensors. The particulate matter generation module uses an oxygen sensor to monitor the oxygen concentration in the mixed gas in real time, and controls the total amount of air intake and the amount of exhaust gas mixed into the intake air through an electronically controlled air valve, thereby controlling the air-fuel ratio to produce particulate matter through incomplete combustion of kerosene. The PM sensor module uses a PM sensor in the test pipeline to detect the time when the current reaches a preset threshold, determines the concentration of particulate matter in the exhaust gas, and displays it on the display unit.

[0007] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0008] 1. This PM sensor smoke detection testing device based on air-fuel ratio control utilizes a multi-voltage output circuit in its power supply module to distribute voltages according to the operating voltages required by different sensors, maintaining the normal operation of the sensors. The particulate matter generation module uses an oxygen sensor to monitor the oxygen concentration in the mixed gas in real time. It controls the total amount of air intake and the amount of exhaust gas mixed into the intake air through an electronically controlled air valve, thereby controlling the air-fuel ratio. This causes incomplete combustion of kerosene in diesel heating to generate particulate matter. It achieves real-time adjustment of the air-fuel ratio based on the oxygen concentration in the mixed gas, thus accurately controlling the amount of particulate matter generated. This lays the foundation for subsequent PM sensor testing and allows for the recycling of exhaust gas, reducing energy consumption.

[0009] 2. The PM sensor module uses the time it takes for the current of the PM sensor in the test pipeline to reach a preset threshold to determine the concentration of particulate matter in the exhaust gas, which is then displayed by the display unit. When multiple PM sensors are powered on, a magnetic field is generated between the positive and negative electrodes, and the particulate matter in the exhaust gas is adsorbed, gradually forming a conductive path. The concentration of particulate matter is determined based on the time it takes for the electrode current to reach a preset value, thus improving the accuracy of PM sensor smoke detection.

[0010] As a further improvement to this technical solution, the power supply module includes a multi-voltage output circuit, wherein the multi-voltage output circuit includes a voltage regulator LM, a Zener diode VD, and an inductor L;

[0011] Pin 1 of the voltage regulator LM is connected to the input voltage UI and one end of capacitor C1. Pin 4 of the voltage regulator LM is connected to one end of resistor R1 and one end of resistor R2. The other end of resistor R1 is connected to the other end of capacitor C1 and pins 3 and 5 of the voltage regulator LM. Pin 2 of the voltage regulator LM is connected to the negative terminal of Zener diode VD and one end of inductor L. The other end of inductor L is connected to one end of capacitor C3 and the other end of resistor R2. Capacitor C2 is connected in parallel with resistor R2. Capacitor C3 is connected in parallel with the output voltage UO.

[0012] The beneficial effect of adopting the above-mentioned further improvements is that by independently controlling the power supply of each part through multiple voltage output modules (such as adjusting the core voltage according to the CPU load), a dynamic balance between performance and power consumption can be achieved, ensuring the normal operation of each sensor.

[0013] As a further improvement to this technical solution, the particulate matter generation module uses an exhaust gas circulation pipe to mix the exhaust gas discharged from the diesel heater into the intake air. By adjusting the opening and closing degree of the two electrically controlled gas valves, the ratio of intake air volume to exhaust gas volume is controlled, thereby regulating the air-fuel ratio.

[0014] As a further improvement to this technical solution, the particulate matter generation module adds the warm air generated by the diesel heating operation back into the test pipeline to ensure that the PM sensor operates at a normal temperature and accelerates the dew point temperature release process of the PM sensor.

[0015] The beneficial effects of the above-mentioned further improvements are that, in conjunction with an oxygen sensor to monitor the oxygen concentration in the mixed gas in real time, a closed-loop control of "monitoring-adjustment-feedback" can be formed, improving the air-fuel ratio control accuracy to ±5%, and reducing the particulate matter concentration fluctuation range from ±30% in traditional open-loop control to ±10%. By flexibly adjusting the proportion of the two gas valves, the degree to which the air-fuel ratio deviates from the theoretical value can be precisely controlled, thereby generating particulate matter of different concentrations, meeting the testing requirements of PM sensors in different pollution scenarios. The exhaust gas components in the exhaust gas recirculation (such as incompletely burned hydrocarbons) have a certain degree of stability, and after mixing with fresh air, the composition of the mixed gas can be made more uniform, thereby ensuring the consistency of kerosene combustion state.

[0016] The sensitive element of the PM sensor is temperature-sensitive and requires an environment above 35°C to function properly. The heating gas generated by the diesel heater is about 250°C. After being introduced into the test area through the pipeline, the gas temperature in the test pipeline can be maintained above 35°C. This avoids the sensor sensitivity from decreasing or the response from lagging due to low ambient temperature. The reuse of hot gas forms a continuous temperature compensation mechanism, which can offset the impact of ambient temperature changes on the test pipeline. In traditional systems without this function, if the ambient temperature fluctuates by 5°C, the sensor probe temperature may fluctuate by 3°C, resulting in a current output deviation of more than 10%.

[0017] As a further improvement to this technical solution, the test unit is equipped with multiple PM sensors in the test pipeline. When the PM sensors are powered on, a magnetic field is generated between the positive and negative electrodes. The particulate matter in the exhaust gas is adsorbed and gradually forms a conductive path. The particulate matter concentration is determined based on the time it takes for the electrode current to reach a preset value.

[0018] The beneficial effect of the above-mentioned further improvements is that five PM sensors under test and one standard sensor can be installed simultaneously, and the electrode current data of each sensor can be collected synchronously via the CAN bus. For example, when testing 10 sensors, the traditional single-sensor test needs to be repeated 10 times, taking about 50 minutes, while the parallel test only takes 10 minutes, improving efficiency by 5 times. The multi-sensor parallel test, combined with automated data processing, can complete the acquisition of multiple sets of data at one time, avoiding repeated operations such as adjusting the diesel heater and adjusting the air-fuel ratio.

[0019] As a further improvement to this technical solution, the display unit displays the sensor type, status, electrode current, and probe temperature parameters during testing, and displays the time required for each sensor to reach the same current. The first sensor is a standard sensor, and the current output acquisition data is displayed in curve form through curve display.

[0020] As a further improvement to this technical solution, the display unit uses a CAN bus and a 485 communication interface to communicate with the outside world.

[0021] The beneficial effects of the above-mentioned further improvements are that they clearly display the current sensor program type and working status, avoiding mistests caused by sensor model confusion or abnormal status. When parameters exceed the normal range (such as electrode current being 0 for a long time or probe temperature dropping suddenly), the system can report errors through the "information prompt box" and quickly locate the fault point in conjunction with the status display. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0023] Figure 2 This is a circuit diagram of the multi-voltage output circuit of this utility model;

[0024] Figure 3 This is a schematic diagram of the particulate matter generation process of this utility model.

[0025] The meanings of the labels in the diagram are as follows:

[0026] 100 Power supply module; 200 Particulate matter generation module; 300 PM sensor module; 310 Testing unit; 320 Display unit. Detailed Implementation

[0027] The technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0028] Currently, traditional PM sensor smoke detection devices simply reduce the amount of air entering the system without establishing a real-time feedback mechanism. This method is easily affected by factors such as ambient air pressure and pipeline resistance, resulting in fluctuating particulate matter concentrations and poor stability. Furthermore, it cannot recycle exhaust gas, leading to energy waste. In order to control the total amount of air entering the system and the amount of exhaust gas mixed into the intake air, thereby controlling the air-fuel ratio, and providing feedback on the air-fuel ratio control based on the oxygen concentration in the mixed gas, stable particulate matter can be generated, improving the accuracy of PM sensor smoke detection and reducing energy consumption.

[0029] like Figure 1 As shown, this utility model provides a PM sensor smoke detection testing device based on air-fuel ratio control, including a power supply module 100, a particulate matter generation module 200 and a PM sensor module 300. The PM sensor module 300 includes a testing unit 310 and a display unit 320.

[0030] The power supply module 100 uses a multi-voltage output circuit to distribute voltages according to the operating voltage required by different sensors, maintaining the normal operation of the sensors. The particulate matter generation module 200 uses an oxygen sensor to monitor the oxygen concentration in the mixed gas in real time, and controls the total amount of air intake and the amount of exhaust gas mixed into the intake air through an electronically controlled air valve, thereby controlling the air-fuel ratio to prevent the incomplete combustion of kerosene in the diesel heater and generate particulate matter. The PM sensor module 300 uses a PM sensor in the test pipeline to detect the time when the current reaches a preset threshold, determines the concentration of particulate matter in the exhaust gas, and displays it on the display unit 320.

[0031] like Figure 2 As shown, the power supply module 100 includes a multi-voltage output circuit, which includes a voltage regulator LM, a Zener diode VD, and an inductor L.

[0032] Pin 1 of voltage regulator LM is connected to the input voltage UI and one end of capacitor C1. Pin 4 of voltage regulator LM is connected to one end of resistor R1 and one end of resistor R2. The other end of resistor R1 is connected to the other end of capacitor C1 and then to pins 3 and 5 of voltage regulator LM. Pin 2 of voltage regulator LM is connected to the negative terminal of Zener diode VD and one end of inductor L. The other end of inductor L is connected to one end of capacitor C3 and the other end of resistor R2. Capacitor C2 is connected in parallel with resistor R2. Capacitor C3 is connected in parallel with output voltage UO.

[0033] Among them, the voltage regulator LM is the LM2596 voltage regulator, which provides all active functions for the buck switching regulator. It can output a drive current of 3A and can be used in fixed output voltages of 3.3V, 5V, and 12V as well as adjustable output versions. It has excellent linearity and load regulation characteristics and operates at a switching frequency of 150kHz. It can be paired with small filter components. Its self-protection functions include two-stage frequency reduction current limiting of the output switch and overheat shutdown with full protection under fault conditions.

[0034] In this circuit, resistors R1 and R2 form a voltage divider network. The performance of the converter is adjusted by inductor L. The larger the inductance value, the smaller the ripple of the output voltage, but the slower the response speed of the circuit; the smaller the inductance value, the larger the ripple, but the faster the response speed. Capacitor C1 is used to filter out low-frequency noise and fluctuations in the input voltage, and capacitor C3 is used to filter out high-frequency noise and ripple in the output voltage, improving the stability of the output voltage. Based on the voltage information fed back by the voltage divider network formed by resistors R1 and R2, the output duty cycle is automatically adjusted, thereby adjusting the output voltage and distributing the voltage according to the operating voltage required by different sensors.

[0035] In order to better control the air-fuel ratio, the particulate matter generation module 200 uses the exhaust gas circulation pipe to mix the exhaust gas discharged from the diesel heater into the intake air. By adjusting the opening and closing degree of the two electronically controlled gas valves, the ratio of intake air volume to exhaust gas volume is controlled, thereby regulating the air-fuel ratio.

[0036] The exhaust gas recirculation system achieves dynamic control of the air-fuel ratio through the coordinated adjustment of electrically controlled valve 1 (controlling the amount of fresh air intake) and electrically controlled valve 2 (controlling the amount of exhaust gas mixed in). For example:

[0037] Increasing the opening of the electronically controlled gas valve 1 increases the amount of fresh air, thereby increasing the oxygen concentration and bringing the air-fuel ratio closer to the theoretical value (14.7:1), resulting in more complete kerosene combustion and reduced particulate matter generation.

[0038] Increasing the opening of the electronically controlled gas valve 2 → increases the amount of exhaust gas mixed in → reduces the oxygen concentration → air-fuel ratio is less than 14.7:1 → exacerbates incomplete combustion of kerosene, increasing particulate matter generation.

[0039] By flexibly adjusting the ratio of the two gas valves, the degree to which the air-fuel ratio deviates from the theoretical value can be precisely controlled, thereby generating particulate matter of different concentrations to meet the testing needs of PM sensors in various pollution scenarios. For example:

[0040] When it is necessary to simulate a high concentration of particulate matter environment, the opening degree of the electronically controlled gas valve 2 can be increased (e.g., opened to 80%) to reduce the air-fuel ratio to 12:1, resulting in more carbon particles from the incomplete combustion of kerosene.

[0041] When simulating low-concentration scenarios, the opening degree of the electronically controlled gas valve 1 can be increased (e.g., opened to 70%) to make the air-fuel ratio close to 14:1, thereby reducing the amount of particulate matter generated.

[0042] like Figure 3 As shown, air enters the pipe from the left. The electronically controlled air valve 1 controls the amount of fresh air intake. The exhaust gas generated by the diesel heater flows through the exhaust gas circulation path. The electronically controlled air valve 2 controls the amount of exhaust gas entering the mixing pipe. The two mix in the pipe. The oxygen sensor monitors the oxygen concentration in the mixed gas in real time to adjust the air-fuel ratio. The air fan sends the mixed gas into the diesel heater. At the same time, kerosene is supplied to the diesel heater from the storage device on the right. Combustion reaction occurs inside the diesel heater, generating hot gas containing particulate matter. The hot gas is discharged from the right side of the diesel heater and can be used for subsequent testing, such as PM sensor testing, to realize the generation of particulate matter and the control of related parameters.

[0043] In order to better recycle the heating, the particulate matter generation module 200 adds the heating generated by the diesel heating operation back into the test pipeline, ensuring that the PM sensor operates at a normal temperature and accelerating the dew point temperature release process of the PM sensor.

[0044] The sensitive element of the PM sensor is temperature sensitive and can only work normally in an environment above 35℃. The heating air generated by the diesel heater is about 250℃. After being introduced into the test area through the pipeline, the gas temperature in the test pipeline can be maintained above 35℃, avoiding the sensor sensitivity decrease or response lag due to the ambient temperature being too low. The reuse of hot air forms a continuous temperature compensation mechanism, which can offset the impact of ambient temperature changes on the test pipeline. When the traditional system does not integrate this function, if the ambient temperature fluctuates by 5℃, the sensor probe temperature may fluctuate by 3℃, resulting in a current output deviation of more than 10%.

[0045] Dew point temperature release refers to the process of removing condensate from the sensor surface before testing. Hot gas reuse can raise the gas temperature in the test pipeline above the dew point temperature, accelerating the evaporation of condensate. For example, in an environment with 60% humidity, dew point release takes 5 minutes without hot gas reuse, but after introducing hot gas, the release time can be shortened to 1 minute, improving test preparation efficiency by 80%.

[0046] The sensor needs to be heated to 785°C for regeneration before each measurement stage. If the temperature of the test pipeline is too low, the heat during the regeneration stage will be quickly absorbed by the environment, resulting in a longer regeneration time. Reusing hot gas can keep the test pipeline in a preheated state, reducing the time to heat to the target temperature during regeneration from 30 seconds to 15 seconds, and reducing the overall test cycle (such as multi-sensor parallel testing) by more than 20%.

[0047] In order to better test the PM sensor, the test unit 310 is equipped with multiple PM sensors in the test pipeline. When the PM sensor is powered on, a magnetic field is generated between the positive and negative electrodes. The particulate matter in the exhaust gas is adsorbed and gradually forms a conductive path. The particulate matter concentration is determined according to the time it takes for the electrode current to reach the preset value.

[0048] When the PM sensor is powered on, a magnetic field is generated between the positive and negative electrodes. Particulate matter is adsorbed to form a conductive path. The current gradually increases as particulate matter is deposited. When the current reaches a preset threshold, a detection cycle is completed. The shorter the response time, the higher the particulate matter concentration. This mechanism determines the concentration by quantifying the time parameter (rather than the simple current value), which can avoid misjudgment caused by the difference in sensitivity between different sensors.

[0049] When testing multiple sensors simultaneously, if most sensors have the same response time (e.g., all 15s), and only one sensor has a response time of 20s, that sensor can be identified as abnormal (e.g., chip contamination or circuit failure), thus avoiding result deviations caused by mismeasurements from a single sensor. The document mentions that "the first sensor is the standard sensor," and other sensors can be calibrated using the standard sensor's time reference, with the error range controlled within ±30%.

[0050] In order to better display the test results, the display unit 320 displays the sensor type, status, electrode current, and probe temperature parameters during the test, and displays the time required for each sensor to reach the same current. The first sensor is a standard sensor, and the current output acquisition data is displayed in curve form through curve display.

[0051] The time list uses the first sensor as the standard, and the response times of other sensors are compared with the standard value to directly reflect the sensitivity differences. For example, if the standard sensor reaches the threshold current in 15 seconds, and the sensor under test takes 18 seconds, then its sensitivity is 83% of the standard value, and performance evaluation can be completed without manual calculation.

[0052] The system features simultaneous display of response times from multiple sensors, enabling simultaneous comparative testing of up to five sensors, a five-fold increase in efficiency compared to testing a single sensor sequentially. For example, while a traditional method would take 50 minutes to test 10 sensors, the time list mode takes only 10 minutes, and the data comparison is more intuitive.

[0053] The curve plots time on the x-axis and current on the y-axis, showing the real-time change in current caused by particulate matter deposition. It also displays the software's operating status and error messages in real time, making it easier for users to identify and resolve problems promptly and improving the reliability of the test.

[0054] In order to better communicate with the outside world, the display unit 320 uses a CAN bus and a 485 communication interface to communicate with the outside world;

[0055] CAN bus is a serial communication protocol that employs a multi-master contention bus architecture, where nodes communicate via messages. In the CAN bus, data is encapsulated into frames with a fixed format, including a start-of-frame field, arbitration field, control field, data field, CRC field, acknowledge field, and end-of-frame field. When multiple nodes transmit data simultaneously, priority is determined by an identifier in the arbitration field; the smaller the identifier, the higher the priority. Nodes with higher priority can transmit data first, thus avoiding bus conflicts.

[0056] The CAN bus and the 485 communication interface work together in the PM sensor smoke detector testing device, giving full play to their respective advantages. The CAN bus is responsible for the real-time data acquisition of sensors and the rapid interaction between devices, ensuring the timely transmission of test data and the collaborative operation of devices. The 485 communication interface focuses on long-distance, multi-device communication connections, realizing centralized control of various modules of the testing device and stable data transmission with external devices, jointly ensuring the efficient and reliable operation of the testing device.

[0057] In summary, the working principle of this solution is as follows:

[0058] This PM sensor smoke detection testing device based on air-fuel ratio control uses a power supply module 100 with a multi-voltage output circuit to distribute voltages according to the operating voltage required by different sensors, maintaining the normal operation of the sensors. The particulate matter generation module 200 uses an oxygen sensor to monitor the oxygen concentration in the mixed gas in real time, and controls the total amount of air intake and the amount of exhaust gas mixed into the intake air through an electronically controlled air valve, thereby controlling the air-fuel ratio. This causes incomplete combustion of kerosene in the diesel heater to generate particulate matter. It realizes real-time adjustment of the air-fuel ratio based on the oxygen concentration in the mixed gas, thereby accurately controlling the amount of particulate matter generated, laying the foundation for subsequent PM sensor testing, and recycling the exhaust gas to reduce energy consumption.

[0059] The PM sensor module 300 uses the time it takes for the current of the PM sensor in the test pipeline to reach a preset threshold to determine the concentration of particulate matter in the exhaust gas, which is then displayed by the display unit 320. When multiple PM sensors are powered on, a magnetic field is generated between the positive and negative electrodes, and the particulate matter in the exhaust gas is adsorbed, gradually forming a conductive path. The concentration of particulate matter is determined based on the time it takes for the electrode current to reach a preset value, thereby improving the accuracy of PM sensor smoke detection.

[0060] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A PM sensor smoke sensing device based on air-fuel ratio control, characterized by: It includes a power supply module (100), a particulate matter generation module (200), and a PM sensor module (300), wherein the PM sensor module (300) includes a testing unit (310) and a display unit (320); The power supply module (100) uses a multi-voltage output circuit to distribute voltage to different sensors according to their required operating voltages, thus maintaining the normal operation of the sensors. The particulate matter generation module (200) uses an oxygen sensor to monitor the concentration of oxygen in the mixed gas in real time, and controls the total amount of air intake and the amount of exhaust gas mixed into the intake air through an electronically controlled air valve, thereby controlling the air-fuel ratio so that the kerosene in the diesel heater is incompletely burned to generate particulate matter. The PM sensor module (300) uses a PM sensor in the test pipeline to detect the time when the current reaches a preset threshold, determines the concentration of particulate matter in the exhaust gas, and displays it on the display unit (320).

2. The PM sensor smoke detection testing device based on air-fuel ratio control according to claim 1, characterized in that: The power supply module (100) includes a multi-voltage output circuit, which includes a voltage regulator LM, a Zener diode VD, and an inductor L. Pin 1 of the voltage regulator LM is connected to the input voltage UI and one end of capacitor C1. Pin 4 of the voltage regulator LM is connected to one end of resistor R1 and one end of resistor R2. The other end of resistor R1 is connected to the other end of capacitor C1 and pins 3 and 5 of the voltage regulator LM. Pin 2 of the voltage regulator LM is connected to the negative terminal of Zener diode VD and one end of inductor L. The other end of inductor L is connected to one end of capacitor C3 and the other end of resistor R2. Capacitor C2 is connected in parallel with resistor R2. Capacitor C3 is connected in parallel with the output voltage UO.

3. The PM sensor smoke detection testing device based on air-fuel ratio control according to claim 1, characterized in that: The particulate matter generation module (200) uses the exhaust gas circulation pipe to mix the exhaust gas discharged from the diesel heater into the intake air. By adjusting the opening and closing degree of the two electrically controlled gas valves, the ratio of intake air volume to exhaust gas volume is controlled, thereby regulating the air-fuel ratio.

4. The PM sensor smoke detection testing device based on air-fuel ratio control according to claim 1, characterized in that: The particulate matter generation module (200) adds the warm air generated by the diesel heating operation back into the test pipeline to ensure that the PM sensor operates at a normal temperature and accelerates the dew point temperature release process of the PM sensor.

5. The PM sensor smoke detection testing device based on air-fuel ratio control according to claim 1, characterized in that: The test unit (310) installs multiple PM sensors in the test pipeline. When the PM sensors are powered on, a magnetic field is generated between the positive and negative electrodes. The particulate matter in the exhaust gas is adsorbed and gradually forms a conductive path. The particulate matter concentration is determined according to the time it takes for the electrode current to reach a preset value.

6. The PM sensor smoke detection testing device based on air-fuel ratio control according to claim 1, characterized in that: The display unit (320) displays the sensor type, status, electrode current, and probe temperature parameters during the test, and displays the time required for each sensor to reach the same current. The first sensor is a standard sensor, and the current output acquisition data is displayed in curve form through curve display.

7. The PM sensor smoke detection testing device based on air-fuel ratio control according to claim 1, characterized in that: The display unit (320) communicates with the outside world using a CAN bus and a 485 communication interface.

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