A method for remote monitoring of real road emissions of heavy duty vehicles

Abstract

This invention relates to a method for calculating the actual road emissions of heavy-duty vehicles under remote monitoring. Based on the three-zone moving average window method, a three-zone moving average window model is established using a fixed duration of 300 seconds. The corresponding load ratio is calculated based on the carbon dioxide emissions of each window. The window, moving second by second, is divided into idling, low-load, and medium-high load zones according to the load ratio. Emission values ​​for the three zones are calculated, and it is verified whether the emissions in each zone exceed the limits. The beneficial effects are: This invention solves the current limitation of existing calculation methods for verifying the actual driving emission levels of vehicles after receiving emission data from networked vehicles on a remote platform. It can fully utilize networked vehicle emission data, taking into account emission data under idling and low-load conditions. It has no strict requirements on vehicle load and data continuity, does not distinguish between vehicle types, simplifies the monitoring procedure, and has strong adaptability and wide application range.

Description

Technical Field

[0001] This invention belongs to the field of environmental monitoring technology, and in particular relates to a method for calculating the actual road emissions of heavy vehicles through remote monitoring. Background Technology

[0002] To better control emissions from heavy-duty vehicles, 11 ministries, including the Ministry of Ecology and Environment, jointly proposed to "promote the construction of a remote online monitoring system for heavy-duty diesel vehicles." After years of development, the remote monitoring system for heavy-duty vehicles has gradually improved its functions, and the number of connected vehicles has also increased. However, there is currently no proposed or invented method for using the large amount of emission data received from the remote platform to establish a monitoring model, verify and calculate the emissions of connected vehicles, and achieve effective monitoring of vehicle emission levels. The China VI emission standard for heavy-duty vehicles has added a vehicle-based emission testing method, incorporating real-world emissions (PEMS) testing into the regulation of heavy-duty vehicle emissions. By specifying factors affecting vehicle emissions, such as vehicle load and the proportion of driving conditions, the test cycle of the real-world driving measurement method is made closer to the actual operating conditions of the vehicle. However, the China VI standard uses the power-based window method to calculate the real-world emissions results of heavy-duty vehicles, which requires the average power of the effective window to be greater than 10%. This results in the exclusion of a large amount of low-power, high-NOx emission data from engines, seriously underestimating the NOx emission levels of heavy-duty vehicles in actual road conditions, especially in urban areas. Furthermore, in actual use of heavy-duty vehicles, the actual operating conditions are more complex and diverse than the PEMS test cycle, and even vehicles of the same model may have significantly different actual operating conditions. Therefore, the power-based window method cannot effectively monitor emissions under low-load conditions. For some test results, if the effective window ratio is low, a large proportion of test data will be sacrificed. At the same time, when applied to remote monitoring of heavy-duty vehicle emissions focusing on a single vehicle, it also faces shortcomings such as the actual operating conditions of networked vehicles not meeting the requirements for the driving condition allocation ratio, and the single run time not meeting the minimum test time requirement. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the above-mentioned technologies and provide a method for calculating the actual road emissions of heavy-duty vehicles through remote monitoring. Based on the emission big data received by the remote platform, a remote monitoring model is established to verify and calculate the emission status of networked vehicles. This method can achieve emission monitoring applicable to the actual operating conditions of vehicles and also take into account idling and low-load conditions, thereby realizing effective monitoring of vehicle emission levels, meeting the requirements of the ecological and environmental authorities for remote supervision of heavy-duty vehicle emissions, and improving supervision efficiency.

[0004] To achieve the above objectives, this invention employs the following technical solution: a method for remotely monitoring and calculating actual road emissions from heavy-duty vehicles, based on a three-zone moving average window method. A three-zone moving average window model is established using a fixed duration of 300 seconds. The corresponding load ratio is calculated based on the carbon dioxide emissions of each window. The window, moving second by second, is divided into an idling zone, a low-load zone, and a medium-to-high-load zone according to the load ratio. The emission values ​​for the three zones are calculated, and it is verified whether the emissions in the three zones exceed the limits. The specific steps are as follows:

[0005] Step 1) Input data from the remote monitoring platform: Use the daily monitoring data of each vehicle on the remote monitoring platform as input. If the data is insufficient, supplement it forward day by day.

[0006] Step 2) Data cleaning: Filtering and removing data from remote monitoring systems;

[0007] Step 3) Moving Window Load Ratio Calculation: Divide the valid data into moving windows, and calculate the load ratio of each moving window according to the formula.

[0008]

[0009] Where: L is the load ratio of the window, which is the CO2 test result of the vehicle model according to Appendix L of GB17691-2018, in g·(kW·h)-1; Pmax is the rated power of the vehicle engine, in kW; twin is the duration of the moving window, recommended to be 300s; is the sampling time interval, 1s; and is the instantaneous CO2 emission of the vehicle, in g·s-1.

[0010] Step 4) Three-zone division: Based on the window load ratio L calculated in Step 3), divide each moving window into different types: idle zone, low load zone, and medium-high load zone;

[0011] Step 5) Confirm that the cumulative number of windows in each region is greater than or equal to the required minimum number of windows n. min =2400, otherwise return to step 1), and supplement the previous day's data:

[0012] Step 6) Calculate the emission values ​​for the three zones: For the calculation of emission values ​​for the low-load zone and the medium-to-high-load zone, the formula is used.

[0013]

[0014] In the formula, Ea,b represents the specific emissions of the zone, in g·(kW·h)⁻¹; a represents the emissions, which can be HC, CO, NOx, or PM; b represents the zone type, which can be a low-load zone or a medium-to-high-load zone; represents the number of windows in the zone; and represents the instantaneous emissions of the emissions, in g·s⁻¹.

[0015] The calculation of the emission flow rate in the idling range is based on the formula.

[0016]

[0017] In the formula, Ea,idle is the emission flow rate in the idle speed area, with the unit of g·h-1;

[0018] Step 7) Verify whether the emissions in the three areas exceed the limit: Set the emission limit according to regulatory requirements. If there is an area where the emissions exceed the limit, it is recorded that the emissions exceed the standard on that day;

[0019] Step 8) Calculate the percentage of days with emissions exceeding the standard: Statistically analyze whether the proportion of days with emissions exceeding the standard for this vehicle over a period of time is greater than x%. If the proportion of days with emissions exceeding the standard for this vehicle is greater than x%, it is determined that this vehicle is an over-emission vehicle, and it is output that the vehicle emissions exceed the standard. Otherwise, return to Step 1) to calculate the emission situation for the next day. 0 < x < 100, and it can be selected according to actual regulatory needs.

[0020] Furthermore, the principles for screening and eliminating the remote monitoring data in Step 2) are as follows:

[0021] (1) The driving altitude of the vehicle is less than 2500 m, that is, the atmospheric pressure is approximately greater than 74 kPa;

[0022] (2) The engine is in a non-shutdown state, that is, the engine speed is greater than 500 r / min;

[0023] (3) The engine is in a warm state, that is, the coolant temperature is greater than 70 °C;

[0024] (4) The NOx sensor of the vehicle can normally transmit valid NOx concentration values.

[0025] Furthermore, for the calculation of the load ratio of the moving window in Step 3), the calculation formula for diesel vehicles is:

[0026] In the formula, is the engine fuel flow rate, with the unit of L·h-1, which is a remote monitoring upload data item; is the diesel density, with the unit of g·L-1.

[0027] Furthermore, for the division of the three areas in Step 4): Among them, the windows with L ≤ 6% are divided into the idle speed area, the windows with 6 < L ≤ 20% are divided into the low load area, and the windows with L > 20% are divided into the medium and high load areas.

[0028] Beneficial effects: The present invention can solve the current situation that there are great limitations in the existing calculation methods for verifying the actual driving emission levels of vehicles after the remote platform receives the emission data of networked vehicles. It can make full use of the emission data of networked vehicles, take into account the emission data under idle speed and low load conditions, have no strict requirements for vehicle load and data continuity, do not distinguish vehicle types, simplify the monitoring procedure, have strong adaptability of the monitoring method, and a wide application range. Description of the Drawings

[0029] Figure 1 This is a three-zone moving average window model diagram;

[0030] Figure 2 This is an example diagram showing the distribution of invalid and valid data;

[0031] Figure 3 It is a moving window partition map. Detailed Implementation

[0032] To better understand the above-mentioned objects, features, and advantages of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. The described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit the present invention.

[0033] In the various embodiments of the present invention, for ease of description and not limitation of the invention, the term "connection" used in the present invention patent application specification and claims is not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Above," "below," "underneath," "left," "right," etc., are only used to indicate relative positional relationships, and when the absolute position of the described object changes, the relative positional relationship also changes accordingly.

[0034] See appendix for details Figure 1 This embodiment provides a method for calculating the actual road emissions of heavy-duty vehicles under remote monitoring. Based on the three-zone moving average window method, a three-zone moving average window model is established with a fixed duration of 300 seconds. The corresponding load ratio is calculated based on the carbon dioxide emissions of each window. The window, which moves second by second, is divided into an idling zone, a low-load zone, and a medium-high load zone according to the load ratio. The emission values ​​of the three zones are calculated, and it is checked whether the emissions of the three zones exceed the limits. The specific steps are as follows:

[0035] Step 1) Input data from the remote monitoring platform: Use the daily monitoring data of each vehicle on the remote monitoring platform as input. If the data is insufficient, supplement it forward day by day.

[0036] Step 2) Data cleaning: Filtering and removing data from remote monitoring systems;

[0037] Step 3) Moving window load ratio calculation: Divide the valid data into moving windows, calculate the load ratio of each moving window, according to the formula

[0038]

[0039] where: L is the load ratio of this window, which is the CO2 test result of this vehicle type according to Appendix L of GB17691-2018, with the unit of g·(kW·h)-1; Pmax is the rated power of the vehicle engine, with the unit of kW; twin is the duration of the moving window, recommended to be 300 s; is the sampling time interval, 1 s; is the instantaneous CO2 emission of the vehicle, with the unit of g·s-1;

[0040] Step 4) Three-zone division: According to the window load ratio L calculated in Step 3) and divide each moving window into different types of idle zone, low load zone and medium-high load zone; among them, the windows with L≤6% are divided into the idle zone, the windows with 6<L≤20% are divided into the low load zone, and the windows with L>20% are divided into the medium-high load zone.

[0041] Step 5) Confirm that the cumulative window number in each zone is greater than or equal to the required minimum window number n min = 2400, otherwise return to Step 1), supplement the data of the previous day:

[0042] Step 6) Calculate the emission values of the three zones: For the calculation of the emission values of the low load zone and the medium-high load zone, according to the formula

[0043]

[0044] where, Ea,b is the specific emission of this zone, with the unit of g·(kW·h)-1; a is the emission substance, which can be HC, CO, NOx and PM; b is the type of the zone, which can be the low load zone or the medium-high load zone; is the window number of this zone; is the instantaneous emission amount of the emission substance, with the unit of g·s-1;

[0045] For the calculation of the emission flow rate of the idle zone, according to the formula

[0046]

[0047] where, Ea,idle is the emission flow rate of the idle zone, with the unit of g·h-1; [[ID=…]] [[ID=…]]

[0048] Step 7) Verify whether the emissions of the three zones exceed the limits: Set the emission limits according to the regulatory requirements. If there is a zone whose emissions exceed the emission limits, it is recorded that the emissions exceed the standards on that day;

[0049] Step 8) Calculate the percentage of days exceeding emission standards: Calculate whether the percentage of days exceeding emission standards for this vehicle over a certain period is greater than x%. If the percentage is greater than x%, the vehicle is considered an over-emission vehicle, and the output "Vehicle emissions exceed standards" is output. Otherwise, return to Step 1) to calculate the emissions for the next day. 0 < x < 100, which can be selected according to actual regulatory needs.

[0050] In this preferred embodiment, the principle for filtering and eliminating remote monitoring data in step 2) is as follows:

[0051] (1) The vehicle travels at an altitude of less than 2500m, which means the atmospheric pressure is approximately greater than 74kPa;

[0052] (2) The engine is not stopped, that is, the engine speed is greater than 500 r / min;

[0053] (3) The engine is in a hot state, that is, the coolant temperature is greater than 70°C;

[0054] (4) The vehicle NOx sensor can transmit the effective NOx concentration value normally.

[0055] In this preferred embodiment, the calculation formula for the load ratio of the moving window in step 3) for diesel vehicles is as follows:

[0056] In the formula, is the engine fuel flow rate in L·h⁻¹, is the data item uploaded by remote monitoring, and is the diesel density in g·L⁻¹.

[0057] Example

[0058] For the current remote monitoring requirements, the emission pollutants generally refer to NOx. Taking an N2 category truck with a maximum gross weight of 4495kg and an engine displacement of 2.289L as an example, the following steps can achieve the desired effect.

[0059] Step 1, Input remote platform data: Use the daily monitoring data of each vehicle on the remote monitoring platform as input. If the data volume is insufficient, it will be supplemented forward day by day.

[0060] Step 2, Data Cleaning: The remote monitoring data is filtered and discarded. The principles for selecting valid data are as follows:

[0061] (1) The vehicle travels at an altitude of less than 2500m, which means the atmospheric pressure is approximately greater than 74kPa;

[0062] (2) The engine is not stopped, that is, the engine speed is greater than 500 r / min;

[0063] (3) The engine is in a hot state, that is, the coolant temperature is greater than 70°C;

[0064] (4) The vehicle NOx sensor can transmit the effective NOx concentration value normally.

[0065] Taking the actual operating data of this truck for 2400 seconds as an example, Figure 2 The distribution of valid and invalid data is presented. It can be seen that after the vehicle has been running for a period of time, the engine coolant temperature may be below 70℃, and the vehicle is not fully warmed up; data from this point should be discarded. Even after the coolant temperature rises above 70℃, the NOx sensor still needs some time to start transmitting valid data; invalid NOx data from this point also needs to be discarded. The valid data after data cleaning no longer meets the operating condition allocation ratio for N2 category non-urban vehicles, but the three-zone division can still be performed using this method.

[0066] Step 3, Calculate the load ratio of the moving window: Divide the valid data into moving windows and calculate the load ratio of each moving window.

[0067] Step 4, Three-zone division: Based on the window load ratio L calculated in Step 3 and the three-zone division method, each moving window is divided into different types.

[0068] Taking the truck's 3600s valid data as an example, Figure 3 The diagram shows the changes in vehicle speed and calculated load ratio over time. Each point on the load ratio curve represents the calculated load ratio within a 300-second moving window following that point, as shown in the boxed area of ​​the diagram. It can be seen that the load ratio curve is correlated with the vehicle speed curve. When the vehicle speed is high, the engine load is high, the load ratio increases, and the moving window enters the medium-to-high load zone. As the vehicle speed decreases, the engine load decreases, and the load ratio also decreases. When the load ratio is less than 20%, the moving window enters the low load zone. When the vehicle is stationary for a long period, the engine is idling, and the load ratio continues to decrease. When the load ratio is less than 6%, the moving window enters the idle zone. This implementation partitions all valid data points, allowing them to participate in emissions calculations.

[0069] Step 5: Confirm that the cumulative number of windows in each region is greater than or equal to the required minimum number of windows n. min =2400, otherwise return to step 1 and supplement the previous day's data.

[0070] Step 6: Calculate the emission values ​​for the three zones respectively. For the low-load zone and the medium-high load zone, calculate the specific emission. For the idling zone, calculate the emission flow rate.

[0071] Step 7: Verify whether the emissions in the three zones exceed the limits. If any zone exceeds the emission limits, it will be recorded as exceeding the emission standards for that day. The emission limits are set according to regulatory requirements.

[0072] Two test vehicles were selected and tested under random operating conditions close to actual operation. Operating data for each vehicle was acquired via remote monitoring. The test results were analyzed using this method, and the vehicle specifications and results are shown in the table.

[0073] Table 1. Calculation results using the three-zone moving average window method

[0074]

[0075] It can be seen that, under unrestricted load and random operating conditions, the effective data window division of both vehicles meets the minimum window number requirement for the three zones. Specifically, when vehicle 1 was running under no-load conditions, the idle zone window accounted for the highest proportion, reaching 34.0% of the total windows; while when vehicle 2 was running under near-full load conditions, the medium-high load zone window accounted for the highest proportion, reaching 44.6% of the total windows. It can be observed that the actual load during vehicle use is significantly affected by the vehicle load and operating conditions. Therefore, in actual supervision, emission values ​​under different loads, especially idling and low-load conditions, should be fully considered and included in regulatory accounting.

[0076] Step 8: Calculate the percentage of days exceeding emission standards. Determine if the percentage of days exceeding standards for this vehicle over a given period is greater than x%. If the percentage is greater than x%, the vehicle is considered an over-emission vehicle, and the system outputs "Vehicle Emissions Exceed Standards." Otherwise, return to Step 1 to calculate the emissions for the next day. 0 < x < 100, which can be selected based on actual regulatory needs.

[0077] The above detailed description of a method for calculating the actual road emissions of a remotely monitored heavy vehicle, with reference to the embodiments, is illustrative rather than limiting. Several embodiments may be listed within the defined scope. Therefore, variations and modifications that do not depart from the overall concept of the present invention should be within the protection scope of the present invention.

Claims

1. A method for calculating actual road emissions from heavy-duty vehicles under remote monitoring, characterized by: Based on the three-zone moving average window method, a three-zone moving average window model is established with a fixed duration of 300 seconds. The corresponding load ratio is calculated based on the carbon dioxide emissions in each window. The window, moving second by second, is divided into idling zone, low load zone, and medium-high load zone according to the load ratio. The emission values ​​in the three zones are calculated, and it is checked whether the emissions in the three zones exceed the limits. The specific steps are as follows: Step 1) Input data from the remote monitoring platform: Use the daily monitoring data of each vehicle on the remote monitoring platform as input. If the data is insufficient, supplement it forward day by day. Step 2) Data cleaning: Filtering and removing data from remote monitoring systems; Step 3) Moving Window Load Ratio Calculation: Divide the valid data into moving windows, and calculate the load ratio of each moving window according to the formula. In the formula: L This represents the load ratio for that window. The CO2 test results for this vehicle are based on Appendix L of GB17691-2018, and the unit is g•(kW•h). -1 ; P max This refers to the rated power of the vehicle's engine, measured in kW. t win The duration of the moving window is 300 seconds; The sampling time interval is 1 second. The instantaneous CO2 emissions of a vehicle, expressed in g•s. -1 ; Step 4) Three-zone division: Based on the window load ratio calculated in Step 3) L And divide each moving window into different types: idle zone, low load zone, and medium-high load zone; Step 5) Confirm that the cumulative number of windows in each zone is greater than or equal to the required minimum number of windows. n min =2400, otherwise return to step 1), supplement the previous day's data: Step 6) Calculate the emission values ​​for the three zones: For the calculation of emission values ​​for the low-load zone and the medium-to-high-load zone, use the formula... In the formula, E a,b for b The specific emissions of the region, expressed in g•(kW•h). -1 ; a The emissions are HC, CO, NOx, and PM; b The type of zone is either a low-load zone or a medium-to-high-load zone; This refers to the number of windows in this area; The instantaneous emission rate of the pollutant, expressed in g•s. -1 ; The calculation of the emission flow rate in the idling range is based on the formula. In the formula, E a,idle This refers to the emission flow rate in the idling range, expressed in g•h. -1 ; Step 7) Check whether the emissions in the three zones exceed the limits: Emission limits are set according to regulatory requirements. If there are zones that exceed the emission limits, they are recorded as exceeding the emission standards for that day. Step 8) Calculate the percentage of days exceeding emission standards: Calculate whether the percentage of days exceeding emission standards for this vehicle over a period of time is greater than x%. If the percentage of days exceeding emission standards for this vehicle is greater than x%, then the vehicle is identified as an over-emission vehicle, and the vehicle emission standards are output. Otherwise, return to Step 1) Calculate the emission situation for the next day; 0 < x < 100. Select according to actual regulatory needs.

2. The method for calculating the actual road emissions of heavy-duty vehicles under remote monitoring according to claim 1, characterized in that: Step 2) The principles for filtering and eliminating remote monitoring data are as follows: (1) The vehicle travels at an altitude of less than 2500 m, or the atmospheric pressure is approximately greater than 74 kPa; (2) The engine is not stopped, or the engine speed is greater than 500 r / min; (3) The engine is in a hot state, or the coolant temperature is greater than 70°C; (4) The vehicle NOx sensor can transmit the effective NOx concentration value normally.

3. The method for calculating actual road emissions of heavy-duty vehicles under remote monitoring according to claim 1, characterized in that: Step 3) If the calculation is for the load ratio of the sliding window of a diesel vehicle, the formula is as follows: In the formula, Engine fuel flow rate, in L•h -1 ; This refers to the density of diesel fuel, expressed in g•L. -1 .

4. The method for calculating the actual road emissions of heavy-duty vehicles under remote monitoring according to claim 1, characterized in that: Step 4) The three-zone division: where, L Windows with a percentage ≤6% are classified as the idle zone, and those with a percentage <6% are classified as the idling zone. L Windows with ≤20% load are classified as low-load zones. L Windows with more than 20% capacity are classified as medium-to-high load zones.

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