Testing method for actual road emission factors of motor vehicles based on coupling of PEMS and vehicle networking

Abstract

The present invention discloses a method for testing the actual road emission factors of motor vehicles based on the coupling of PEMS and the Internet of Vehicles, introduces VSP and Bin, and uses PEMS testing to establish a PEMS-based motor vehicle actual road emission database of different pollutants VSPBin; calculates the actual road VSP value of the motor vehicle; divides the VSPBin interval according to the actual road VSP value of the motor vehicle; establishes a PEMS-tested motor vehicle actual road pollutant VSPBin emission rate library; uses the Internet of Vehicles technology to obtain a regional motor vehicle actual road operating condition database; a method for calculating the actual road emission factors of a single vehicle based on the coupling of PEMS and the Internet of Vehicles; a method for calculating the transient emission factors of a single vehicle based on the coupling of PEMS and the Internet of Vehicles; and a method for calculating the error of the actual road emission factors of a single vehicle based on the coupling of PEMS and the Internet of Vehicles. The present invention can efficiently and quickly obtain emission factor data under the actual road conditions of the vehicle, saving manpower, expenses and other costs.

Description

Technical Field

[0001] The present invention belongs to the technical field of actual road emission factor testing of motor vehicles, and in particular, relates to an actual road emission factor testing method for motor vehicles based on coupling of PEMS and vehicle networking. Background Art

[0002] Relevant research shows that motor vehicle pollutant emissions are affected by multiple factors such as emission control technology, actual road conditions, road traffic flow, operating environment, vehicle age, oil type and vehicle quality, resulting in significant deviations between actual road and laboratory emission test results.

[0003] The portable vehicle emission measurement system (PEMS) can directly obtain the gaseous and particulate pollutant emission data of motor vehicles on actual roads, and has the advantages of strong data stability, good shock resistance, and fast response speed. It overcomes the shortcomings of traditional vehicle / engine bench testing technology and methods, and truly characterizes the motor vehicle pollutant emissions and operating conditions under actual road conditions and their influence relationship, providing reliable data for the analysis of the characteristics of motor vehicle exhaust emissions pollutants.

[0004] However, in actual applications, the PEMS test method has problems such as high cost, long cycle, and limited emission data acquisition, which makes it difficult to meet the needs of large-scale actual road emission testing of different types of motor vehicles. Therefore, PEMS testing has not been widely used in national and local management departments in the testing and evaluation of motor vehicle emissions. With the development of technologies such as "Internet +", OBD (On-Board Diagnostic) and cloud computing, my country has taken the lead in proposing the need for online monitoring of heavy-duty diesel vehicles in the world. By equipping heavy-duty diesel vehicles in different regions with on-board emission monitoring terminals, it is possible to synchronously collect, organize and analyze the actual operating conditions and emissions of diesel vehicles in different operating areas and matching different pollution control devices, breaking the traditional single-vehicle emission testing and data analysis methods, and providing data for government heavy-duty diesel vehicle emission monitoring, construction of actual road conditions of different types of vehicles in the region, establishment of emission inventory and comprehensive management and control.

[0005] However, when obtaining the actual road condition data of motor vehicles through the Internet of Vehicles, due to abnormal GPRS signals, network disconnection, data storage errors, network congestion for concurrent data uploads, etc., abnormal data such as mutations, losses, and drifts may appear in the online monitoring of the Internet of Vehicles. Therefore, the online data of the Internet of Vehicles needs to be cleaned before data analysis and application. Summary of the invention

[0006] The purpose of the present invention is to provide a method for testing the actual road emission factors of motor vehicles based on the coupling of PEMS and the Internet of Vehicles, so as to efficiently and quickly obtain the emission factor data of the vehicle under actual road conditions, and provide technical support for domestic local management departments and enterprises to carry out actual road emission factor testing and inventory establishment of motor vehicles.

[0007] The present invention is achieved through the following technical solutions:

[0008] The actual road emission factor test method for motor vehicles based on the coupling of PEMS and vehicle networking is as follows:

[0009] (1) Select motor vehicles covering emission stages, fuel types, power types and usage types in the region, conduct actual road emission tests using PEMS equipment, and obtain data such as vehicle speed, emission rates of different pollutants (g / s), engine output power, and engine speed under actual road conditions;

[0010] (2) Calculate the actual road VSP value of the motor vehicle; VSP systematically represents the changes in kinetic energy and potential energy during the actual operation of the motor vehicle, and the work done by the engine to overcome air resistance and rolling friction. It is a physical quantity with vector properties. Its calculation formula is as follows:

[0011]

[0012] Where: KE and PE are the kinetic energy and potential energy in actual road operation, N·m; F r is the rolling friction resistance during driving, N; g is the acceleration due to gravity, which is 9.81 m / s 2 ; F A is air resistance, N; C R is the rolling damping coefficient of the tire and road during driving, usually ranging from 0.0085 to 0.016; v is the driving speed, m / s; a is the transient acceleration during driving, m / s 2 ρ a is the air density, which is 1.207kg / m at 20℃ 3 ; V m is the wind speed, m / s; m is the curb weight, kg; ε i is the mass factor of the motor vehicle, dimensionless; h is the geographical altitude when driving, m; C D is the drag coefficient during driving, dimensionless; A is the frontal area, m 2 ; θ is the road slope;

[0013] (3) Divide the VSP Bin intervals according to the actual road VSP values ​​of motor vehicles;

[0014] (4) Establish a VSP Bin emission rate library of actual road pollutants for motor vehicles based on PEMS testing

[0015] Through the above (1) to (3), a VSP Bin emission rate database of actual road pollutants of motor vehicles based on PEMS testing is established. The VSP Bin database contains the following information: vehicle type, usage type, fuel type, power type, emission stage, and pollutant emission rates in different Bin intervals;

[0016] (5) Using Internet of Vehicles technology to obtain a database of actual road operating conditions of regional motor vehicles

[0017] Install OBD vehicle terminal equipment on N vehicles in the area to obtain the actual road operation data of the vehicles, and transmit the operation data remotely online to the motor vehicle Internet of Vehicles online monitoring system through GPRS and Internet of Vehicles technology;

[0018] After synchronously receiving the actual road operation data of N online vehicles, the online monitoring system of the vehicle network obtains the VSP and Bin feature distribution of the actual road conditions of each motor vehicle in the area according to the above (2) to (3), and establishes a VSP and Bin feature value database based on the actual road condition big data of the vehicle network;

[0019] (6) Calculation method of actual road emission factor of a single vehicle based on coupling of PEMS and vehicle network

[0020] Through the emission rate database of different Bin intervals, on this basis, by obtaining the actual operating conditions of the vehicle in each region, the actual road emission factor of the vehicle can be calculated and analyzed, that is, the emission rate of each pollutant in the VSP Bin interval and the corresponding frequency distribution are used to calculate the corresponding pollutant emission factor:

[0021]

[0022] Where: EF i is the emission factor of pollutant i under actual road conditions of motor vehicles, g / km; D i is the frequency distribution of the jth Bin interval, %; ER ij is the emission rate of pollutant i in the jth Bin interval, g / s; v is the average speed of the actual road condition, m / s;

[0023] (7) Calculation method of transient emission factor of a single vehicle on actual road based on coupling of PEMS and vehicle network

[0024] Actual road PEMS transient data are used to calculate the emission rates (ER) of different pollutants based on different vehicle emission technology types and micro-operation modes. i,j,k , g / s):

[0025]

[0026] Where: i, j, k, n and t are the motor vehicle emission technology type, emission pollutant type, Bin interval, vehicle and test time respectively; ER i,j,k is the average emission rate of pollutant j of technology type i in Bin interval k, g / s; ER i,j,k,n,t is the emission rate of pollutant j in technology type i in bin interval k for the nth test vehicle at the tth second, g / s; T i,k,n is the total time of the nth test vehicle in Bin interval k in technology type i, s; N i Total number of vehicles tested for technology type i;

[0027] (8) Error calculation method of single vehicle actual road emission factor based on coupling of PEMS and vehicle network

[0028] On the basis of calculating the average emission rate of each bin interval of motor vehicles, the average emission rate of different vehicle bin intervals under different motor vehicle technology types is comprehensively considered; therefore, ER i,j,k The standard deviation comes from two aspects, including all instantaneous emission rates and the difference in the modal average emission rates between different vehicles:

[0029]

[0030]

[0031] Where: ER i,j,k,n S is the average emission rate of pollutant j of the nth test vehicle in the motor vehicle technology type i in Bin interval k; ERi,j,k,n For ER i,j,k,n,t The standard deviation of pollutant j in Bin interval k.

[0032] Preferably, for light vehicles, the formula proposed in the above formula (1) is sorted out and refined to obtain the transient VSP:

[0033] VSP=v×(1.1a+9.81[atan(sinθ)]+0.132)+0.000302v 3 (6)

[0034] For heavy vehicles, the MOVES model VSP method is used:

[0035]

[0036] Where: are the road load factors, in units of kW / smt and kW / s 2 .m 2 .t, kW / s 3 .m 3 .t.

[0037] According to the actual road driving status and VSP of motor vehicles, the transient working conditions of motor vehicles are divided into several Bin intervals, each Bin corresponds to different pollutant emission rates, and then the relationship between transient working conditions and emissions is established. By selecting motor vehicles with typical characteristics such as emission stage, fuel type, power type, and use type (public transportation, sanitation, taxi, etc.) in the region, actual road emission tests are carried out using PEMS equipment. The test conditions and test methods should meet the requirements of national standards GB 18352.6-2016 and GB 17691-2018.

[0038] Based on the PEMS test, the present invention introduces the motor vehicle emission specific power VSP and Bin analysis method. Through the actual road emission PEMS test, a basic database of motor vehicle actual VSPBin interval emission rates under different vehicle types, emission stages, fuel types and operating conditions is established, which can truly reflect the actual road operation emission characteristics of vehicles. On this basis, local management departments in China can obtain the actual operating condition big data and Bin interval characteristics of various types of motor vehicles in the region through the vehicle network online monitoring method, and then after coupling with the Bin interval emission rate basic database, they can efficiently and quickly obtain the emission factor data under the actual road conditions of vehicles in the region.

[0039] The beneficial effect of the present invention is that through the actual road motor vehicle emission test technical method based on the coupling of on-board emission test PEMS and vehicle network online monitoring, the emission factor data of the vehicle under actual road conditions can be obtained efficiently and quickly, saving manpower, expenses and other costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a flow chart of the testing method of the present invention;

[0041] Figure 2 Obtain a schematic diagram of the actual road operation conditions of regional motor vehicles for vehicle networking technology;

[0042] Figure 3-Figure 6 A schematic diagram showing the comparison of the actual road PEMS test results of typical motor vehicles and the pollutant emissions obtained by coupling PEMS with the Internet of Vehicles;

[0043] Figure 2 In: 1-N connected vehicle vehicles in the region, 2-connected vehicle online monitoring system for motor vehicles, 3-actual road emission factor testing device for motor vehicles, 4-VSPBin database of actual roads for motor vehicles based on PEMS. DETAILED DESCRIPTION

[0044] Embodiments of the present invention are now described with reference to the accompanying drawings. It will be understood by those skilled in the art that the following embodiments are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention.

[0045] The actual road emission factor testing method for motor vehicles based on PEMS and vehicle networking coupling provided by the present invention comprises the following steps:

[0046] (1) Using PEMS to test the VSPBin database of actual roads for motor vehicles based on PEMS, select motor vehicles with typical characteristics such as emission stage, fuel type, power type and use type (public transportation, sanitation, taxi, etc.) in the region, and use PEMS equipment to carry out actual road emission tests; the test conditions and test methods should meet the requirements of national standards GB 18352.6-2016 and GB 17691-2018. The test conditions meet the following requirements (Table 1):

[0047] Table 1 Vehicle type and test road condition time ratio distribution

[0048]

[0049] The actual road emission database of motor vehicles based on PEMS testing contains information (including but not limited to, and can be expanded): vehicle type (micro / small / medium / heavy, passenger and freight vehicles); usage type (public transportation, sanitation, postal service, etc.); fuel type (gasoline, diesel, natural gas); power type (traditional gasoline, traditional diesel, hybrid power), emission stage (National 0 to National VI stage), and pollutant emission rate under the entire test cycle (CO, CO2, HC, NOx, PM, unit: g / s).

[0050] (2) Calculate the actual road VSP value of the motor vehicle; VSP systematically represents the changes in kinetic energy and potential energy during the actual operation of the motor vehicle, and the work done by the engine to overcome air resistance and rolling friction. It is a physical quantity with vector properties. Its calculation formula is as follows:

[0051]

[0052] Where: KE and PE are the kinetic energy and potential energy in actual road operation, N·m; F r is the rolling friction resistance during driving, N; g is the acceleration due to gravity, which is 9.81 m / s 2 ; F A is air resistance, N; C R is the rolling damping coefficient of the tire and road during driving, usually ranging from 0.0085 to 0.016; v is the driving speed, m / s; a is the transient acceleration during driving, m / s 2 ρ a is the air density, which is 1.207kg / m at 20℃ 3; V m is the wind speed, m / s; m is the curb weight, kg; ε i is the mass factor of the motor vehicle, dimensionless; h is the geographical altitude when driving, m; C D is the drag coefficient during driving, dimensionless; A is the frontal area, m 2 ; θ is the road slope;

[0053] (3) According to the actual road VSP value of the motor vehicle, the VSP bin interval is divided; considering the actual road VSP distribution characteristics of the motor vehicle, the Bin interval division in the study starts from less than or equal to -8kW / t, with an increment of 2kW / t, and gradually increases to more than 12kW / t, totaling 15 intervals, and the second-by-second emission rate values ​​falling in each interval are averaged. Finally, according to the actual road driving status and VSP distribution of the motor vehicle, a total of 38 Bin intervals are determined (as shown in Table 2), among which: Bin0 and Bin1 are deceleration and idling intervals respectively; Bin2-13 is a low-speed interval; Bin14~25 is a medium-speed interval; Bin26~37 is a high-speed interval.

[0054] Table 2 Bin classification standards under actual operating conditions of motor vehicles

[0055]

[0056] (4) Establish a VSPBin emission rate library of actual road pollutants for motor vehicles based on PEMS testing

[0057] Through the above (1) to (3), a VSPBin emission rate database of actual road pollutants of motor vehicles based on PEMS testing is established. The VSPBin database contains the following information (including but not limited to, and can be expanded): vehicle type (micro / small / medium / heavy, passenger and freight vehicles), use type (public transportation, sanitation, postal service, etc.), fuel type (gasoline, diesel, natural gas), power type (traditional gasoline, traditional diesel, hybrid power), emission stage (National 0 to National VI stage), and pollutant emission rates in different Bin intervals (CO, CO2, HC, NOx, PM, unit: g / s);

[0058] (5) Using Internet of Vehicles technology to obtain a database of actual road operating conditions of regional motor vehicles

[0059] pass Figure 2 In the process, OBD vehicle terminal devices are installed on N connected vehicle vehicles in the area to obtain the actual road operation data of the vehicles, and the operation data is remotely transmitted online to the connected vehicle online monitoring system of the motor vehicle through GPRS and connected vehicle technology. The data collection and transmission frequency is 1Hz;

[0060] After synchronously receiving the actual road operation data of N online vehicles, the online monitoring system of the vehicle network obtains the VSP and Bin feature distribution of the actual road conditions of each motor vehicle in the area according to the above (2) to (3), and establishes a VSP and Bin feature value database based on the actual road condition big data of the vehicle network;

[0061] (6) Calculation method of actual road emission factor of a single vehicle based on coupling of PEMS and vehicle network

[0062] Through the emission rate database of different Bin intervals, on this basis, by obtaining the actual operating conditions of the vehicle in each region, the actual road emission factor of the vehicle can be calculated and analyzed, that is, the emission rate of each pollutant in the VSP Bin interval and the corresponding frequency distribution are used to calculate the corresponding pollutant emission factor:

[0063]

[0064] Where: EF i is the emission factor of pollutant i under actual road conditions of motor vehicles, g / km; D i is the frequency distribution of the jth Bin interval, %; ER ij is the emission rate of pollutant i in the jth Bin interval, g / s; v is the average speed of the actual road condition, m / s;

[0065] (7) Calculation method of transient emission factor of a single vehicle on actual road based on coupling of PEMS and vehicle network

[0066] Actual road PEMS transient data are used to calculate the emission rates (ER) of different pollutants based on different vehicle emission technology types and micro-operation modes. i,j,k , g / s):

[0067]

[0068] Where: i, j, k, n and t are the motor vehicle emission technology type, emission pollutant type, Bin interval, vehicle and test time respectively; ER i,j,k is the average emission rate of pollutant j of technology type i in Bin interval k, g / s; ER i,j,k,n,t is the emission rate of pollutant j in technology type i in bin interval k for the nth test vehicle at the tth second, g / s; T i,k,n is the total time of the nth test vehicle in Bin interval k in technology type i, s; N i Total number of vehicles tested for technology type i;

[0069] (8) Error calculation method of single vehicle actual road emission factor based on coupling of PEMS and vehicle network

[0070] On the basis of calculating the average emission rate of each bin interval of motor vehicles, the average emission rate of different vehicle bin intervals under different motor vehicle technology types is comprehensively considered; therefore, ER i,j,k The standard deviation mainly comes from two aspects, including all transient emission rates and the difference in modal average emission rates between different vehicles:

[0071]

[0072]

[0073] Where: ER i,j,k,n S is the average emission rate of pollutant j of the nth test vehicle in the motor vehicle technology type i in Bin interval k; ERi,j,k,n For ER i,j,k,n,t The standard deviation of pollutant j in Bin interval k.

[0074] Furthermore, for light vehicles, the formula proposed in the above formula (1) is sorted out and refined to obtain the transient VSP:

[0075] VSP=v×(1.1a+9.81[atan(sinθ)]+0.132)+0.000302v 3 (6)

[0076] For heavy vehicles, the MOVES model VSP method is used:

[0077]

[0078] Where: are the road load factors, in units of kW / smt and kW / s 2 .m 2 .t, kW / s 3 .m 3 .t. Based on the typical motor vehicle information in China, the road load factor is determined as shown in Table 3.

[0079] Table 3 Road load factors for different types of motor vehicles

[0080]

[0081] According to the above method, taxis, buses, sanitation and postal services with different emission stages, fuel types and power types were selected in Tangshan City to carry out actual road emission factor tests of motor vehicles based on PEMS and vehicle networking coupling, and compared with the actual road PEMS test results to verify the accuracy of the actual road emission factor test method of motor vehicles based on PEMS and vehicle networking coupling, such as Figure 3-Figure 6 As shown, where: Figure 3 For CO emission comparison, Figure 4For CO2 emission comparison, Figure 5 For THC emission comparison, Figure 6 For NOx emission comparison.

[0082] The results show that the deviation range of CO emission is -25.0% to 21.4%; the deviation range of CO2 emission is -14.9% to 14.5%; the deviation range of THC emission is -19.1% to 21.1%; the deviation range of NOx emission is -21.5% to 26.7%. In general, the deviation of the data results between the two methods is controlled within the range of ±30%, which also meets the requirement of GB18352.6-2016 that the actual road PEMS test should be less than 150% (1.5 times) of the laboratory vehicle drum emission limit. This shows that by obtaining the actual road working condition characteristic data of different types of motor vehicles and coupling with the corresponding type of motor vehicle Bin emission rate library established by the actual road PEMS test, the pollutant emission characteristics of motor vehicles under actual road operation can be obtained relatively quickly and accurately.

[0083] The above disclosure is only the preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made according to the scope of the patent application of the present invention are still within the scope covered by the present invention.

Claims

1. A method for testing the actual road emission factors of motor vehicles based on the coupling of PEMS and vehicle networking, characterized in that: Here are the steps: (1) Select motor vehicles covering emission stages, fuel types, power types and usage types in the region, conduct actual road emission tests using PEMS equipment, and obtain data on vehicle speed, emission rates of different pollutants, engine output power and engine speed under actual road conditions; (2) Calculate the actual road VSP value of the motor vehicle; VSP systematically represents the changes in kinetic energy and potential energy during the actual operation of a motor vehicle, and the work done by the engine to overcome air resistance and rolling friction. It is a physical quantity with vector properties, and its calculation formula is as follows: Where: KE and PE are the kinetic energy and potential energy in actual road operation, N·m; F r is the rolling friction resistance during driving, N; g is the acceleration due to gravity, which is 9.81 m / s 2 ; F A is air resistance, N; C R is the rolling damping coefficient of the tire and road during driving, usually ranging from 0.0085 to 0.016; v is the driving speed, m / s; a is the transient acceleration during driving, m / s 2 ρ a is the air density, which is 1.207kg / m at 20℃ 3 ; V m is the wind speed, m / s; m is the curb weight, kg; ε i is the mass factor of the motor vehicle, dimensionless; h is the geographical altitude when driving, m; C D is the drag coefficient during driving, dimensionless; A is the frontal area, m 2 ; θ is the road slope; (3) Divide the VSPBin interval according to the actual road VSP value of the motor vehicle; (4) Establish a VSPBin emission rate library of actual road pollutants for motor vehicles based on PEMS testing Through the above (1) to (3), a VSPBin emission rate database of actual road pollutants of motor vehicles based on PEMS testing is established. The VSPBin database contains the following information: vehicle type, usage type, fuel type, power type, emission stage, and pollutant emission rates in different bin intervals; (5) Using Internet of Vehicles technology to obtain a database of actual road operating conditions of regional motor vehicles Install OBD vehicle terminal equipment on N vehicles in the area to obtain the actual road operation data of the vehicles, and transmit the operation data remotely online to the motor vehicle Internet of Vehicles online monitoring system through GPRS and Internet of Vehicles technology; After synchronously receiving the actual road operation data of N online vehicles, the online monitoring system of the vehicle network obtains the VSP and Bin feature distribution of the actual road conditions of each motor vehicle in the area according to the above (2) to (3), and establishes a VSP and Bin feature value database based on the actual road condition big data of the vehicle network; (6) Calculation method of actual road emission factor of a single vehicle based on coupling of PEMS and vehicle network Through the emission rate database of different Bin intervals, on this basis, by obtaining the actual operating conditions of the vehicle in each region, the actual road emission factor of the vehicle can be calculated and analyzed, that is, the emission rate of each pollutant in the VSP Bin interval and the corresponding frequency distribution are used to calculate the corresponding pollutant emission factor: Where: EF i is the emission factor of pollutant i under actual road conditions of motor vehicles, g / km; D i is the frequency distribution of the jth Bin interval, %; ER ij is the emission rate of pollutant i in the jth Bin interval, g / s; v is the average speed of the actual road condition, m / s; (7) Calculation method of transient emission factor of a single vehicle on actual road based on coupling of PEMS and vehicle network Actual road PEMS transient data is used to calculate the emission rate of different pollutants based on different vehicle emission technology types and micro-operation modes as ER i,j,k , g / s: Where: i, j, k, n and t are the motor vehicle emission technology type, emission pollutant type, Bin interval, vehicle and test time respectively; ER i,j,k is the average emission rate of pollutant j of technology type i in Bin interval k, g / s; ER i,j,k,n,t is the emission rate of pollutant j in technology type i in bin interval k for the nth test vehicle at the tth second, g / s; T i,k,n is the total time of the nth test vehicle in Bin interval k in technology type i, s; N i Total number of vehicles tested for technology type i; (8) Error calculation method of single vehicle actual road emission factor based on coupling of PEMS and vehicle network On the basis of calculating the average emission rate of each bin interval of motor vehicles, the average emission rate of different vehicle bin intervals under different motor vehicle technology types is comprehensively considered; therefore, ER i,j,k The standard deviation comes from two aspects, including all instantaneous emission rates and the difference in the modal average emission rates between different vehicles: Where: ER i,j,k,n is the average emission rate of pollutant j of the nth test vehicle in the motor vehicle technology type i in the Bin interval k; For ER i,j,k,n,t The standard deviation of pollutant j in Bin interval k.

2. The method for testing the actual road emission factor of a motor vehicle based on the coupling of PEMS and the Internet of Vehicles according to claim 1 is characterized in that: For light vehicles, the formula proposed in formula (1) above is sorted out and refined to obtain the transient VSP: VSP=v×(1.1a+9.81[atan(sinθ)]+0.132)+0.000302v 3 (6) For heavy vehicles, the MOVES model VSP method is used: Where: are the road load factors, in units of kW / smt and kW / s 2 .m 2 .t, kW / s 3 .m 3 .t.

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