A method and apparatus for rapid testing of emissions from off-highway machinery

Abstract

The application relates to a non-road machine emission rapid test method and device, characterized in that: whether the non-road machine to be tested is in a cold start state is judged; whether the non-road machine to be tested has been in a working state is judged; whether the non-road machine to be tested has entered a state in which rapid emission testing can be carried out is judged; short-time continuous test data acquisition is carried out; continuous test data is filtered; the average value of pollutant emission data in a preset test duration is calculated; and an emission test conclusion is obtained. The application establishes a statistical judgment mechanism based on window filtering and sample window mean discreteness analysis, converts the judgment mode into a quantifiable and verifiable technical judgment process, can obtain an emission test result which can be directly compared with a regulation limit value in a short test time, has the advantages of high test efficiency, clear judgment basis and quantifiable result output, and is suitable for application scenes such as non-road machine on-site law enforcement detection, enterprise self-inspection and emission rapid screening.

Description

Technical Field

[0001] This invention relates to the field of emissions testing technology for non-road mobile machinery, and in particular to a rapid testing method and equipment for non-road machinery emissions. Background Technology

[0002] Non-road mobile machinery is a significant source of mobile pollution emissions, widely used in engineering construction, logistics loading and unloading, mining, road construction, and other fields. With increasingly stringent emission regulations, on-site emission testing and rapid screening of non-road machinery have become crucial requirements for environmental supervision.

[0003] Currently, emissions testing for non-road machinery typically employs portable emissions testing systems for operational process testing. While existing portable systems can perform pollutant emission testing, they generally suffer from drawbacks such as large size, complex installation, long on-site setup time, and insufficient adaptability to non-road mobile machinery. Especially for non-road mobile machinery, due to their diverse structural forms and significant differences in exhaust end arrangements, traditional testing equipment often requires additional tooling for installation, resulting in complex on-site operation and difficulty in meeting the needs for rapid testing and batch screening.

[0004] Meanwhile, non-road machinery typically operates continuously in multiple repetitive work cycles during actual operation, with a certain degree of repeatability and stability between different work cycles. Under continuous load operation, if data covering multiple work cycles can be collected in a short period and the representativeness of the short-term test results can be determined, it is expected to replace traditional long-term testing and improve emission testing efficiency. However, existing technologies lack rapid emission testing methods suitable for continuous operation conditions of non-road machinery, especially lacking technical solutions for determining test initiation conditions, confirming continuous load operation status, and determining the representativeness of short-term test results. Summary of the Invention

[0005] To address the problems of long testing times, complex equipment installation and on-site implementation, low testing efficiency, and lack of objective representativeness in short-term test results in existing non-road machinery emission testing, the primary objective of this invention is to provide a rapid non-road machinery emission testing method that improves testing effectiveness and on-site applicability, achieves adaptive adjustment of the representativeness assessment process, has high testing efficiency, clear assessment criteria, and quantifiable output results.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a rapid testing method for non-road machinery emissions, the method comprising the following sequential steps:

[0007] (1) Determine whether the non-road machinery under test is in a cold start state. If the determination result is yes, install the emission rapid test equipment, enable the non-road machinery under test to enter the actual operation process, and monitor the exhaust gas temperature change in real time, and proceed to step (3); if the determination result is no, proceed to step (2).

[0008] (2) If it is determined that the non-road machinery under test is in operation, stop the operation, install the emission rapid test equipment, resume the operation of the non-road machinery under test, and continuously monitor the change of exhaust gas temperature, and proceed to step (3).

[0009] (3) When the exhaust gas temperature is greater than or equal to the preset temperature threshold and the exhaust gas temperature enters a stable state, it is determined that the non-road machinery under test has entered a state where rapid emission testing can be performed, and proceed to step (4); when the exhaust gas temperature is less than the preset temperature threshold, first check whether the rapid emission testing equipment is installed correctly, then continue to monitor the exhaust gas temperature change in real time, and return to this step to continue the judgment.

[0010] (4) Short-term continuous test data acquisition: The emission rapid test equipment continuously samples for a preset test duration to obtain continuous test data, wherein the preset test duration is 5 minutes;

[0011] (5) Filter the continuous test data with a preset initial window length;

[0012] (6) Select a sample window from multiple window means and calculate the relative standard deviation. Determine whether the data meets the representativeness criteria. If the result is yes, proceed to step (7); otherwise, increase the window length and return to step (5).

[0013] (7) Calculate the average value of pollutant emission data within the preset test duration as the test result;

[0014] (8) Compare the test results with the regulatory limits to obtain the emission test conclusions.

[0015] In step (2), the rapid emission testing equipment includes a NOx sensor for detecting NOx in exhaust gas, a temperature sensor for detecting exhaust gas temperature, a main controller for receiving and processing test data, and a wireless communication device for data transmission. The output terminals of the NOx sensor and the temperature sensor are both connected to the input terminal of the main controller, and the output terminal of the main controller is connected to the host computer through the wireless communication device.

[0016] Step (6) specifically refers to: performing sliding window filtering to obtain multiple window averages; the initial window length is preferably 1 minute, and the window average is used to characterize the average level of pollutant emission data within each corresponding time window.

[0017] Step (7) specifically refers to: selecting multiple sample window means from multiple window means, and calculating the dispersion index of the sample window means to determine whether the continuous test data is representative; the sample window means are obtained by random sampling, and the number of sample window means is set according to the total number of window means; when the total number of window means is large, a preset number of sample window means are randomly sampled using a preset random seed for representativeness determination; the dispersion index is the relative standard deviation of the sample window means. When the relative standard deviation is less than the preset threshold, it is determined that the continuous test data has covered enough feature conditions and is statistically representative; when the relative standard deviation is greater than or equal to the preset threshold, it is determined that the continuous test data under the current window length does not meet the representativeness requirement, the window length is increased first, and the process returns to step (6). If the dispersion index is still greater than or equal to the preset threshold after increasing the window length, the window length is increased until the preset window length upper limit is reached; if the dispersion index is still greater than or equal to the preset threshold after the window length reaches the preset window length upper limit, the collection time of the continuous test data is extended, and the process returns to step (5) until the representativeness determination condition is met.

[0018] Step (8) specifically refers to: establishing Emissions mass balance formula:

[0019] (1);

[0020] in, This refers to the volume concentration in the exhaust gas. For regulations Power consumption factor; For exhaust gas quality; The work done by non-road machinery during operating time t is expressed as:

[0021] (2);

[0022] In the formula, Vehicle power; Runtime;

[0023] Exhaust gas quality Represented as:

[0024] (3);

[0025] Substituting formulas (2) and (3) into formula (1), we get:

[0026] (4);

[0027] Simplifying the identical terms on both sides of equation (4), we get:

[0028] (5);

[0029] Rearranging equation (5) yields:

[0030] ;

[0031] In the formula, This represents the corresponding dimensionless volume fraction. λ is the general mechanical fuel consumption factor; λ is the general diesel engine excess air coefficient, a dimensionless number, taken as 2.1;

[0032] If the test result is greater than or equal to If the mechanical emissions exceed the standard, it is determined that the emissions exceed the standard; if the test result is less than the standard... If so, the mechanical emissions are deemed to comply with legal standards.

[0033] The NOx sensor is model 89463-E0480, the temperature sensor is a PT100 RTD, the main control chip is an STM32F10 chip, and the wireless communication device is a 4G module; both the NOx sensor and the temperature sensor are installed at the exhaust pipe of the non-road machinery.

[0034] Another object of the present invention is to provide an electronic device comprising:

[0035] Processor; and

[0036] A memory storing computer program instructions that, when executed by the processor, cause the processor to perform the rapid non-road machinery emissions testing method as described above.

[0037] The present invention also provides a computer-readable storage medium having stored thereon computer program instructions, which, when executed by a processor, cause the processor to perform the non-road machinery emissions rapid testing method as described above.

[0038] As can be seen from the above technical solution, the present invention has the following beneficial effects: First, addressing the key issue of "when to start testing" in rapid emission testing of non-road machinery, the present invention establishes a test start state determination mechanism based on exhaust gas temperature changes. This mechanism can distinguish between different situations such as cold start, on-site operation, and installation abnormalities, avoiding direct start of testing under unstable operating conditions, idling conditions, or equipment malfunctions, thereby improving test effectiveness and on-site applicability. Second, addressing the key issue of whether short-term test results can represent the overall emission level, the present invention establishes a statistical determination mechanism based on window filtering and sample window mean dispersion analysis. By calculating dispersion indicators such as the relative standard deviation of the sample window mean, it can quantitatively evaluate whether short-term continuous test data has covered enough characteristic operating conditions, transforming the original experience-based judgment method into a quantifiable and verifiable technical judgment. The invention has several key features: First, it defines the process; second, when the discreteness index under the current window length does not meet the threshold condition, the invention does not directly reject the test, but rather adopts a progressive processing method that prioritizes increasing the window length for re-judgment and, if necessary, further extends the data acquisition time, thereby achieving adaptive adjustment of the representativeness judgment process, thus balancing test efficiency, result stability, and method robustness; third, the invention is preferably implemented in conjunction with miniaturized rapid emission testing equipment, which makes it easier to deploy and apply in non-road machinery on-site testing scenarios, further improving the implementation convenience and on-site applicability of the invention; fourth, the invention can obtain emission test results that can be directly compared with regulatory limits in a short test time, and has the advantages of high test efficiency, clear judgment basis, and quantifiable output of results, making it suitable for application scenarios such as on-site law enforcement testing of non-road machinery, enterprise self-inspection, and rapid emission screening. Attached Figure Description

[0039] Figure 1 This is a flowchart of the method of the present invention;

[0040] Figure 2 The curves showing the changes in exhaust gas temperature and nitrogen oxide emissions during a 5-minute test period of the excavator. Detailed Implementation

[0041] like Figure 1 As shown, a rapid testing method for non-road machinery emissions includes the following sequential steps:

[0042] (1) Determine whether the non-road machinery under test is in a cold start state. If the determination result is yes, install the emission rapid test equipment, enable the non-road machinery under test to enter the actual operation process, and monitor the exhaust gas temperature change in real time, and proceed to step (3); if the determination result is no, proceed to step (2).

[0043] (2) If it is determined that the non-road machinery under test is in operation, stop the operation, install the emission rapid test equipment, resume the operation of the non-road machinery under test, and continuously monitor the change of exhaust gas temperature, and proceed to step (3).

[0044] (3) When the exhaust gas temperature is greater than or equal to the preset temperature threshold and the exhaust gas temperature enters a stable state, it is determined that the non-road machinery under test has entered a state where rapid emission testing can be performed, and proceed to step (4); when the exhaust gas temperature is less than the preset temperature threshold, first check whether the rapid emission testing equipment is installed correctly, then continue to monitor the exhaust gas temperature change in real time, and return to this step to continue the judgment; the stable state refers to the exhaust gas temperature being greater than or equal to the preset temperature threshold and lasting for about 60 seconds, and the temperature threshold is determined according to the type of non-road machinery under test, engine power, and actual operating load;

[0045] (4) Short-term continuous test data acquisition: The emission rapid test equipment continuously samples for a preset test duration to obtain continuous test data, wherein the preset test duration is 5 minutes;

[0046] (5) Filter the continuous test data with a preset initial window length;

[0047] (6) Select a sample window from multiple window means and calculate the relative standard deviation. Determine whether the data meets the representativeness criteria. If the result is yes, proceed to step (7); otherwise, increase the window length and return to step (5).

[0048] (7) Calculate the average value of pollutant emission data within the preset test duration as the test result;

[0049] (8) Compare the test results with the regulatory limits to obtain the emission test conclusions.

[0050] In step (2), the rapid emission testing equipment includes a NOx sensor for detecting NOx in the exhaust gas, a temperature sensor for detecting the exhaust gas temperature, a main controller for receiving and processing test data, and a wireless communication device for data transmission. The output terminals of the NOx sensor and the temperature sensor are both connected to the input terminal of the main controller, and the output terminal of the main controller is connected to a host computer via the wireless communication device. The host computer is used to receive, clean, verify, calculate, store, and return results of the uploaded data; the test results can be returned to a mobile phone or operating terminal for display.

[0051] Step (6) specifically refers to: performing sliding window filtering to obtain multiple window averages; the initial window length is preferably 1 minute, and the window average is used to characterize the average level of pollutant emission data within each corresponding time window.

[0052] Step (7) specifically refers to: selecting multiple sample window means from multiple window means, and calculating the dispersion index of the sample window means to determine whether the continuous test data is representative; the sample window means are obtained by random sampling, and the number of sample window means is set according to the total number of window means; when the total number of window means is large, a preset number of sample window means are randomly sampled using a preset random seed for representativeness determination; the dispersion index is the relative standard deviation of the sample window means. When the relative standard deviation is less than the preset threshold, it is determined that the continuous test data has covered enough feature conditions and is statistically representative; when the relative standard deviation is greater than or equal to the preset threshold, it is determined that the continuous test data under the current window length does not meet the representativeness requirement, the window length is increased first, and the process returns to step (6). If the dispersion index is still greater than or equal to the preset threshold after increasing the window length, the window length is increased until the preset window length upper limit is reached; if the dispersion index is still greater than or equal to the preset threshold after the window length reaches the preset window length upper limit, the collection time of the continuous test data is extended, and the process returns to step (5) until the representativeness determination condition is met.

[0053] Step (8) specifically refers to: establishing Emissions mass balance formula:

[0054] (1);

[0055] in, This refers to the volume concentration in the exhaust gas. For regulations Power consumption factor; For exhaust gas quality; The work done by non-road machinery during operating time t is expressed as:

[0056] (2);

[0057] In the formula, Vehicle power; Runtime;

[0058] Exhaust gas quality Represented as:

[0059] (3);

[0060] Substituting formulas (2) and (3) into formula (1), we get:

[0061] (4);

[0062] Simplifying the identical terms on both sides of equation (4), we get:

[0063] (5);

[0064] Rearranging equation (5) yields:

[0065] ;

[0066] In the formula, This represents the corresponding dimensionless volume fraction. λ is the general mechanical fuel consumption factor; λ is the general diesel engine excess air coefficient, a dimensionless number, taken as 2.1;

[0067] If the test result is greater than or equal to If the mechanical emissions exceed the standard, it is determined that the emissions exceed the standard; if the test result is less than the standard... If so, the mechanical emissions are deemed to comply with legal standards.

[0068] The NOx sensor is model 89463-E0480, the temperature sensor is a PT100 RTD, the main control chip is an STM32F10 chip, and the wireless communication device is a 4G module; both the NOx sensor and the temperature sensor are installed at the exhaust pipe of the non-road machinery.

[0069] After meeting the initial test conditions, a continuous 5-minute test period is selected as the initial rapid emission test data. The sampling frequency is 1Hz, therefore the 5-minute test period contains 300 sampling points. Subsequently, the 5-minute continuous test data is subjected to sliding window filtering according to a preset initial window length. Preferably, the initial window length is set to 1 minute, i.e., 60 sampling points, and the sliding step size is set to 1 sampling point. After sliding window filtering, 241 window means corresponding to different time positions are obtained. Then, 10 sample window means are randomly selected from the 241 window means using a preset random seed, and the relative standard deviation of the sample window means is calculated to determine whether the current test data is representative.

[0070] The average values ​​of 10 exhaust gas temperature sample windows randomly selected from the above multiple window averages were approximately 437.92℃, 438.30℃, 437.03℃, 433.37℃, 433.45℃, 431.89℃, 432.17℃, 433.25℃, 434.72℃, and 434.42℃, respectively. The average value of the 10 exhaust gas temperature sample windows was approximately 434.65℃, the variance was approximately 4.85, the standard deviation was approximately 2.20, and the relative standard deviation was approximately 0.51%. The overall fluctuation was small, indicating that the exhaust gas temperature was within a stable fluctuation range during the selected test period, which could support the determination of the test start state.

[0071] Furthermore, the mean values ​​of 10 Wet NOx sample windows randomly selected from the same sliding window filtering results are approximately 1030.35, 1028.63, 1066.02, 1113.57, 1111.26, 1078.92, 1082.33, 1089.70, 1083.61, and 1083.92, respectively. The average of these 10 sample window mean values ​​is approximately 1076.83, the variance is approximately 743.21, the corresponding standard deviation is approximately 27.3, and the relative standard deviation is approximately 2.5%. Comparing this dispersion index with a pre-set representativeness threshold shows that it meets the preset judgment conditions, indicating that the current 5-minute test data statistically covers a sufficient number of characteristic operating conditions and can be used to characterize the overall emission level of the excavator under this operating condition.

[0072] Since the relative standard deviation of the sample window mean calculated based on the initial 5-minute test data and the initial window length already meets the preset threshold condition, there is no need to further increase the window length or extend the acquisition time. Subsequently, all Wet NOx data within this 5-minute test period were statistically analyzed, and the overall mean was approximately 1080.86, which was used as the rapid emission test result of the excavator under the corresponding operating conditions. For particulate matter emission data, the same sliding window filtering, random sampling of the sample window mean, and representativeness determination process described above can also be used for analysis.

[0073] Figure 2 The graphs show the changes in exhaust gas temperature, Wet Nox, and Nox after sliding window filtering during a 5-minute test period. Figure 2 It can be seen that the exhaust gas temperature remained within a stable fluctuation range during the selected test period, without any significant continuous cooling process. While the nitrogen oxide emission data fluctuated somewhat with the operating cycle, the overall change was continuous without any abnormal abrupt changes, and the filtered NOx also tended to stabilize. Combined with the results of sliding window filtering and the determination of the relative standard deviation of the sample window mean, this further demonstrates that the test period met the requirements of this invention regarding the determination of the test start state and the representativeness of short-term data, thus verifying the feasibility and effectiveness of this invention for rapid emission testing of non-road machinery. Wet NOx is the wet-basis NOx concentration, measured without removing water vapor from the exhaust gas.

[0074] In summary, this invention addresses the critical issue of "when to start testing" in rapid emission testing of non-road machinery by establishing a test start-up state determination mechanism based on exhaust gas temperature changes. This mechanism can distinguish between different situations such as cold start, on-site operation, and installation abnormalities, avoiding direct testing under unstable operating conditions, idling, or equipment malfunctions, thereby improving test effectiveness and on-site applicability. Furthermore, addressing the critical issue of whether short-term test results can represent overall emission levels, this invention establishes a statistical determination mechanism based on window filtering and sample window mean dispersion analysis. By calculating dispersion indicators such as the relative standard deviation of the sample window mean, it can quantitatively evaluate whether short-term continuous test data has covered sufficient characteristic operating conditions, transforming the previously experience-based judgment method into a quantifiable and verifiable technical judgment process. The current window... When the dispersion index under the specified window length does not meet the threshold condition, this invention does not directly reject the test. Instead, it adopts a progressive processing method that prioritizes increasing the window length for re-judgment and, if necessary, further extends the data acquisition time. This achieves adaptive adjustment of the representativeness judgment process, thus balancing test efficiency, result stability, and method robustness. This invention is preferably implemented in conjunction with miniaturized rapid emission testing equipment, which makes it easier to deploy and apply in non-road machinery on-site testing scenarios, further improving the implementation convenience and on-site applicability of this invention. This invention can obtain emission test results that can be directly compared with regulatory limits in a short test time, and has the advantages of high test efficiency, clear judgment basis, and quantifiable output of results. It is suitable for application scenarios such as on-site law enforcement testing of non-road machinery, enterprise self-inspection, and rapid emission screening.

[0075] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A rapid testing method for emissions from non-road machinery, characterized in that: The method includes the following steps in sequence: (1) Determine whether the non-road machinery under test is in a cold start state. If the determination result is yes, install the emission rapid test equipment, enable the non-road machinery under test to enter the actual operation process, and monitor the exhaust gas temperature change in real time, and proceed to step (3); if the determination result is no, proceed to step (2). (2) If it is determined that the non-road machinery under test is in operation, stop the operation, install the emission rapid test equipment, resume the operation of the non-road machinery under test, and continuously monitor the change of exhaust gas temperature, and proceed to step (3). (3) When the exhaust gas temperature is greater than or equal to the preset temperature threshold and the exhaust gas temperature enters a stable state, it is determined that the non-road machinery under test has entered a state where rapid emission testing can be performed, and proceed to step (4); when the exhaust gas temperature is less than the preset temperature threshold, first check whether the rapid emission testing equipment is installed correctly, then continue to monitor the exhaust gas temperature change in real time, and return to this step to continue the judgment. (4) Short-term continuous test data acquisition: The emission rapid test equipment continuously samples for a preset test duration to obtain continuous test data, wherein the preset test duration is 5 minutes; (5) Filter the continuous test data with a preset initial window length; (6) Select a sample window from multiple window means and calculate the relative standard deviation. Determine whether the data meets the representativeness criteria. If the result is yes, proceed to step (7); otherwise, increase the window length and return to step (5). (7) Calculate the average value of pollutant emission data within the preset test duration as the test result; (8) Compare the test results with the regulatory limits to obtain the emission test conclusions.

2. The rapid testing method for non-road machinery emissions according to claim 1, characterized in that: In step (2), the rapid emission testing equipment includes a NOx sensor for detecting NOx in exhaust gas, a temperature sensor for detecting exhaust gas temperature, a main controller for receiving and processing test data, and a wireless communication device for data transmission. The output terminals of the NOx sensor and the temperature sensor are both connected to the input terminal of the main controller, and the output terminal of the main controller is connected to the host computer through the wireless communication device.

3. The rapid testing method for non-road machinery emissions according to claim 1, characterized in that: Step (6) specifically refers to: performing sliding window filtering to obtain multiple window averages; the initial window length is preferably 1 minute, and the window average is used to characterize the average level of pollutant emission data within each corresponding time window.

4. The rapid testing method for non-road machinery emissions according to claim 1, characterized in that: Step (7) specifically refers to: selecting multiple sample window means from multiple window means, and calculating the dispersion index of the sample window means to determine whether the continuous test data is representative; the sample window means are obtained by random sampling, and the number of sample window means is set according to the total number of window means; when the total number of window means is large, a preset number of sample window means are randomly sampled using a preset random seed to determine representativeness; the dispersion index is the relative standard deviation of the sample window means. When the relative standard deviation is less than the preset threshold, it is determined that the continuous test data has covered enough feature conditions and is statistically representative; when the relative standard deviation is greater than or equal to the preset threshold, it is determined that the continuous test data under the current window length does not meet the representativeness requirement, the window length is increased first, and the process returns to step (6). If the dispersion index is still greater than or equal to the preset threshold after increasing the window length, the window length is increased until the preset window length upper limit is reached. If the discreteness index is still greater than or equal to the preset threshold after the window length reaches the preset upper limit, the collection time of continuous test data is extended, and the process returns to step (5) until the representativeness judgment condition is met.

5. The rapid testing method for non-road machinery emissions according to claim 1, characterized in that: Step (8) specifically refers to: establishing Emissions mass balance formula: （1）； in, This refers to the volume concentration in the exhaust gas. For regulations Power consumption factor; For exhaust gas quality; The work done by non-road machinery during operating time t is expressed as: （2）； In the formula, For vehicle power; Runtime; Exhaust gas quality Represented as: （3）； Substituting formulas (2) and (3) into formula (1), we get: （4）； Simplifying the identical terms on both sides of equation (4), we get: （5）； Rearranging equation (5) yields: ； In the formula, This represents the corresponding dimensionless volume fraction. λ is the general mechanical fuel consumption factor; λ is the general diesel engine excess air coefficient, a dimensionless number, taken as 2.1; If the test result is greater than or equal to If the mechanical emissions exceed the standard, it is determined that the emissions exceed the standard; if the test result is less than the standard... If so, the mechanical emissions are deemed to comply with legal standards.

6. The rapid testing method for non-road machinery emissions according to claim 2, characterized in that: The NOx sensor is model 89463-E0480, the temperature sensor is a PT100 RTD, the main control chip is an STM32F10 chip, and the wireless communication device is a 4G module; both the NOx sensor and the temperature sensor are installed at the exhaust pipe of the non-road machinery.

7. An electronic device, comprising: processor; as well as A memory storing computer program instructions that, when executed by the processor, cause the processor to perform the rapid testing method for non-road machinery emissions as described in any one of claims 1-6.

8. A computer-readable storage medium having stored thereon computer program instructions, which, when executed by a processor, cause the processor to perform the rapid testing method for non-road machinery emissions as described in any one of claims 1-6.

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