CN115655730A - Method for calculating NOx emission in PEMS test of heavy-duty diesel vehicle - Google Patents
Method for calculating NOx emission in PEMS test of heavy-duty diesel vehicle Download PDFInfo
- Publication number
- CN115655730A CN115655730A CN202211397718.XA CN202211397718A CN115655730A CN 115655730 A CN115655730 A CN 115655730A CN 202211397718 A CN202211397718 A CN 202211397718A CN 115655730 A CN115655730 A CN 115655730A
- Authority
- CN
- China
- Prior art keywords
- window
- vehicle
- oil consumption
- nox
- power
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Landscapes
- Combined Controls Of Internal Combustion Engines (AREA)
Abstract
The invention discloses a method for calculating NOx emission in a PEMS test of a heavy-duty diesel vehicle, which comprises the following steps: calculating the accumulated oil consumption according to the test time sequence, defining the accumulated oil consumption reaching the nominal WHTC circulating oil consumption as an oil consumption window, calculating the NOx specific emission of each window according to the concentration of NOx in exhaust, the exhaust flow and the oil consumption-power conversion coefficient, and calculating the ratio of the window average oil consumption rate to the nominal maximum oil consumption rate as the window average specific power; defining a window with the average specific power of the window being more than 20% of the maximum power of the engine as an effective window, and screening the effective windows in all the windows; and sequencing the NOx specific emission values of the effective window, and comparing the obtained specific emission output of NOx at the position of 90% with a preset limit value to judge whether the vehicle meets the requirement. The method can accurately restore the specific emission of the vehicle based on the PEMS power-based window method based on the data items and information in the OBD data stream.
Description
Technical Field
The invention relates to the technical field of emission monitoring of heavy-duty diesel vehicles, in particular to a method for calculating NOx emission in a PEMS test of a heavy-duty diesel vehicle.
Background
Heavy vehicles have a low proportion of the vehicle reserves, but have a large emission of nitrogen oxides and particulate matter. In order to reduce the harm of pollutant emission of heavy vehicles to the atmospheric environment, various motor vehicle emission regulations are successively issued in various countries in the world, and in order to reduce the difference between the actual road emission and the laboratory test cyclic emission result, the technology of applying PEMS to automobile exhaust emission evaluation is rapidly developed.
Currently, monitoring departments have incorporated the actual road driving measurement method (PEMS test) into heavy vehicle emission supervision and employed the power base window method to evaluate the actual road emission of heavy vehicles. The method is a main method for supervising new vehicles and in-use vehicles by a current ecological environment governing department, and comprises the steps of carrying out actual road pollutant emission tests on vehicles by using PEMS and then evaluating the emission level of the whole vehicle by using a power-based window method.
The power-based window method takes the engine WHTC transient test cycle power as a window size standard, accumulates the engine work and pollutant emission data when the vehicle actually runs on a road in a mobile window, the mobile frequency is the same as the sampling frequency, and calculates the pollutant specific emission (g/kW. H) of each window. According to the method, information such as the rotating speed and the torque of the engine when the vehicle runs needs to be read by means of the OBD, and the engine is calculated to do work. However, according to the standard requirements, the torque information in the data collected by the remote emission management vehicle-mounted terminal is the percentage of the maximum reference torque of the engine, the maximum reference torque information of the vehicle is not in the data transmitted by the standard requirements, and meanwhile, the remote emission management vehicle-mounted terminal cannot acquire the transient test cycle power of the WHTC of the vehicle engine, so that the OBD data cannot be directly used for calculating the NOx emission data of the vehicle through a power-based window method of PEMS test, and further the emission condition of the vehicle cannot be accurately judged.
Disclosure of Invention
The invention aims to provide a method for calculating NOx emission in a PEMS test of a heavy-duty diesel vehicle, aiming at solving the problems that in the prior art, OBD data of the vehicle cannot be read completely, reference torque information and WHTC transient test cycle power of the vehicle cannot be obtained, and the NOx emission data of the vehicle cannot be calculated by directly using the OBD data through a power base window method of the PEMS test, so that a high-emission vehicle is judged.
The technical scheme adopted for realizing the purpose of the invention is as follows:
a method for calculating NOx emission in a PEMS test of a heavy-duty diesel vehicle comprises the following steps:
s1, calculating nominal cycle average power of a vehicle under the C-WVC cycle based on a speed time curve of the C-WVC cycle, calculating nominal average fuel consumption rate of the vehicle under the C-WVC cycle according to hundred kilometer fuel consumption information of the C-WVC cycle, and taking the ratio of the nominal average fuel consumption rate of the vehicle to the nominal cycle average power as a vehicle fuel consumption-power conversion coefficient;
s2, calculating to obtain a nominal maximum oil consumption rate of the vehicle according to the maximum power of the engine of the vehicle and the oil consumption-power conversion coefficient;
s3, calculating the nominal WHTC circulating oil consumption of the vehicle according to the nominal maximum oil consumption rate of the vehicle and the WHTC circulating oil consumption coefficient;
s4, eliminating data which do not meet requirements according to requirements on vehicle PEMS data altitude and engine water temperature of the heavy diesel vehicle pollutant emission limit value and standard requirements of a measuring method;
s5, calculating the accumulated oil consumption according to the test time sequence, defining the time consumed by circulating oil when the accumulated oil consumption reaches the nominal WHTC as an oil consumption window, and setting the initial time interval of two adjacent oil consumption windows as 1s;
s6, calculating the specific NOx emission of each window according to the concentration of NOx in exhaust, the exhaust flow and the fuel consumption-power conversion coefficient, and taking the ratio of the average fuel consumption rate of the window to the nominal maximum fuel consumption rate as the average specific power of the window;
s7, defining a window with the average specific power of the window being more than 20% of the maximum power of the engine as an effective window, and screening the effective windows in all the windows;
s8, sequencing the NOx specific emission values of the effective windows, obtaining the specific emission of NOx at 90% of positions, comparing the specific emission with a preset limit value, and if the specific emission is smaller than the preset limit value, indicating that the vehicle meets the requirements.
According to the invention, under the existing OBD data system framework, the specific emission calculation process and calculation results of the vehicle based on the PEMS power-based window method can be accurately reduced based on data items and information in the OBD data stream, and support can be provided for a management department to accurately supervise and screen the in-use high-emission vehicle.
The method solves the problems that a supervision department cannot obtain the reference torque information and WHTC transient test cycle power of the vehicle, and further cannot directly use OBD data to calculate the NOx emission of the vehicle and judge a high-emission vehicle through a power base window method of PEMS test.
The invention relates the hundred kilometer oil consumption of the C-WTVVC test to the specific power of the whole vehicle, and solves the key problems of window division from a power base window to an oil consumption window method, window average specific power calculation, NOx specific emission calculation and the like.
Drawings
FIG. 1 is a schematic diagram of NOx mass emissions versus fuel consumption for the present invention.
FIG. 2 is a flow chart of a method for calculating NOx emissions during a heavy-duty diesel vehicle PEMS test of the present invention.
FIG. 3 is a schematic representation of the vehicle speed distribution of the PEMS test of the present invention.
Detailed Description
The invention is described in further detail below with reference to the figures and specific examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The calculation of the NOx emission in the PEMS test of the heavy-duty diesel vehicle is supported on the basis of oil consumption data in the existing OBD data flow frame, a power base window is replaced by the oil consumption window, the approximate linear relation between the oil consumption and work of the diesel vehicle is used as theoretical support, the calculation result of the NOx specific emission in the PEMS test is accurately reduced, and further support is provided for a management department to accurately monitor and screen vehicles with high emission and violation vehicles.
As shown in fig. 2, the method for calculating NOx emission in the PEMS test of the heavy-duty diesel vehicle according to the embodiment of the present invention includes the following steps:
s1, distributing proportion to characteristic mileage of C-WTVC circulation of a vehicle based on a GB-T27840-2011 heavy commercial vehicle fuel consumption measuring method, confirming road condition proportion of the vehicle in the C-WTVC based on vehicle type and application, referring to a motor vehicle emission Model (MOVES), and combining a calculation formula of Vehicle Specific Power (VSP) to calculate average specific power VSP of the vehicle in the C-WTVC circulation C-WTVC,avg The characteristic mileage distribution ratio of each type of vehicle is shown in table 1, for example. The calculation formula of the average specific power of the C-WTVVC cycle of the vehicle is as follows
VSP C-WTVC,avg ＝α·ν+A·ν+B·ν 3
Among them, VSP C-WTVC,avg Is the average specific power (kW) of the C-WTVVC cycle; alpha is the vehicle acceleration (m/s 2) in the C-WTVVC period; ν is the vehicle speed (m/s) in the C-WTVVC cycle, A and B are road resistance coefficients, and the values are shown in Table 2.
TABLE 1C-WTVVC circulation characteristic mileage distribution ratio
TABLE 2 road resistance coefficient of A and B
The nominal cycle average power (kW) of the vehicle is calculated using the following equation:
where M is the maximum design total mass (kg), η, of the vehicle Trans Is the efficiency of the driveline of the vehicle.
Calculating the nominal average fuel consumption rate FCR of the vehicle under the C-WTVVC circulation according to the hundred kilometers fuel consumption information of the C-WTVVC circulation C-WTVC (L/h), the calculation formula is as follows:
FCR C-WTVC ＝FC C-WTVC /T Total
wherein FC C-WTVC Oil consumption per hundred kilometers (L), T total The nominal hundred kilometers time(s) of the vehicle can be calculated through a C-WTVVC circulating speed time curve and road condition proportion.
The fuel consumption-power conversion coefficient Coeff calculation formula of the vehicle is as follows:
and S2, calculating to obtain the nominal maximum oil consumption rate (kg/h) of the vehicle according to the maximum power of the vehicle engine and the oil consumption-power conversion coefficient. The calculation formula is as follows:
wherein P is Max Is the maximum (net) power (kW) of the vehicle engine.
And S3, calculating the nominal WHTC circulating oil consumption (kg) of the vehicle according to the nominal maximum oil consumption rate of the vehicle and the WHTC circulating oil consumption coefficient. The calculation formula is as follows:
FC WHTC ＝FCR Max ×Rc
in the formula, rc is a WHTC circulating oil consumption coefficient, and the WHTC circulating oil consumption coefficient can be obtained based on a statistical mode according to the actually measured WHTC circulating oil consumption and the maximum oil consumption of a plurality of vehicles.
S4, according to requirements of the GB 17691-2018 heavy-duty diesel vehicle pollutant emission limit value and the measurement method on the vehicle PEMS data altitude and the engine water temperature, eliminating data which do not meet the requirements, such as removing data of the engine water temperature lower than 70 ℃, and removing data of which the altitude is higher than 1700 m.
S5, calculating the accumulated oil consumption according to the test time sequence, wherein the accumulated oil consumption reaches the nominal WHTC circulating oil consumption (FC) WHTC ) The time is defined as a fuel consumption window, and the initial time interval of two adjacent fuel consumption windows is 1s.
The accumulated oil consumption of the oil consumption window should satisfy the following formula, and is shown in fig. 1:
FC(t 2,i )-FC(t 1,i )≥FC WHTC
FC(t 2,i -Δt)-FC(t 1,i )＜FC WHTC ≤FC(t 2,i )-FC(t 1,i )
the FC (t) is the accumulated oil consumption from the initial point of the test to the t moment, and the delta t is the data sampling period (1 s).
M shown in FIG. 1 fuel (t 1 )、m fuel (t 2 )、m fuel (t 2 - Δ t) corresponding to FC (t) 1,i )、FC(t 2,i )、FC(t 2,i Δ t) has the same meaning, FC WHTC And m fuel,cycle Are used in the same sense.
S6, calculating the specific emission of NOx in each window according to the concentration of the NOx in the exhaust, the exhaust flow and the fuel consumption-power conversion coefficient; calculating the ratio of the window average fuel consumption rate to the nominal maximum fuel consumption rate as an average specific power;
wherein, the calculation formula of the NOx emission (mg/kW.h) is as follows:
wherein the mass emission of NOx (mg/s) at each time point is calculated by the formula:
Wherein, the average oil consumption rate (kg/h) of the window is the total oil consumption ratio window time of the window, and the calculation formula is as follows:
the window average specific power calculation formula:
and S7, selecting effective windows with the window average specific power being more than 20% of the maximum power of the engine as the effective windows, screening the effective windows in all the windows, and if the effective window proportion is lower than 50%, reducing the window average specific power threshold value by 1% until the effective window proportion is not lower than 50%. If the window average specific power threshold is reduced to 10%, the effective window proportion is still lower than 50%, and the acquisition result is invalid.
S8, sequencing the effective windows from low to high according to the NOx specific emission value, obtaining the specific emission of NOx at the position of 90%, comparing the specific emission with a preset limit value, and if the specific emission is smaller than the preset limit value, indicating that the vehicle meets the requirements.
In order to verify the reliability of the algorithm, 4 national six-heavy diesel vehicles are selected to carry out the PEMS test, a power base window method and the fuel consumption window method are used for calculating test data, and results are compared.
The PEMS test is carried out according to the national six-emission standard of heavy-duty vehicles, the test route consists of three sections of urban roads, suburban roads and expressway, and the test vehicle speed distribution diagram 3 is shown. The details of the vehicles are shown in table 3, and the WHTC cycle power (kWh) and the hundred kilometer fuel consumption of the C-WTVC cycle corresponding to each vehicle are respectively used as key parameters of a power base window method and a fuel consumption window method.
TABLE 3 details of the vehicle
The calculation results are shown in table 4 below:
compared with a power-based window method, the method provided by the invention has the advantages that the average deviation is less than 6%, and the error is within an allowable range in consideration of the factors that the actual load of the vehicle actually running and the difference between the running road route and the test vehicle exist.
While there have been shown and described the fundamental principles and essential features of the invention and advantages thereof, it will be apparent to those skilled in the art that the invention is not limited to the details of the foregoing exemplary embodiments, but is capable of other specific forms without departing from the spirit or essential characteristics thereof;
the present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.
Claims (8)
1. The method for calculating the NOx emission in the PEMS test of the heavy-duty diesel vehicle is characterized by comprising the following steps of:
s1, calculating nominal circulating average power of a vehicle under the C-WTVC circulation based on a speed-time curve of the C-WTVC circulation, calculating nominal average fuel consumption rate of the vehicle under the C-WTVC circulation according to hundred-kilometer fuel consumption information of the C-WTVC circulation, and taking the ratio of the nominal average fuel consumption rate of the vehicle to the nominal circulating average power as a vehicle fuel consumption-power conversion coefficient;
s2, calculating to obtain a nominal maximum oil consumption rate of the vehicle according to the maximum power of the engine of the vehicle and the oil consumption-power conversion coefficient;
s3, calculating the nominal WHTC circulating oil consumption of the vehicle according to the nominal maximum oil consumption rate of the vehicle and the WHTC circulating oil consumption coefficient;
s4, eliminating data which do not meet requirements according to requirements on vehicle PEMS data altitude and engine water temperature of the heavy diesel vehicle pollutant emission limit value and standard requirements of a measuring method;
s5, calculating the accumulated oil consumption according to the test time sequence, defining the time consumed by circulating oil when the accumulated oil consumption reaches the nominal WHTC as an oil consumption window, and setting the initial time interval of two adjacent oil consumption windows as 1s;
s6, calculating the specific NOx emission of each window according to the concentration of NOx in exhaust, the exhaust flow and the fuel consumption-power conversion coefficient, and taking the ratio of the average fuel consumption rate of the window to the nominal maximum fuel consumption rate as the average specific power of the window;
s7, defining a window with the average specific power of the window being greater than 20% of the maximum power of the engine as an effective window, and screening effective windows in all windows;
s8, sequencing the NOx specific emission values of the effective windows to obtain the specific emission of NOx at 90% of positions, comparing the specific emission with a preset limit value, and if the specific emission is smaller than the preset limit value, indicating that the vehicle meets the requirements.
2. The method of claim 1, wherein the nominal cycle average power of the vehicle is calculated in step S2 using the following equation:
wherein M is the maximum design total mass (kg), η, of the vehicle Trans Efficiency of the vehicle's driveline, P C-WTVC,avg For nominal cyclic average power of vehicle, VSP C-WTVC,avg The average specific power of the vehicle in the C-WTVVC cycle.
3. The method for calculating the NOx emission in the PEMS test of the heavy-duty diesel vehicle according to claim 2, wherein in the step S2, the WHTC circulating oil consumption coefficient is obtained based on a statistical mode according to measured WHTC circulating oil consumption and maximum oil consumption of a plurality of vehicles.
4. The method of claim 3, wherein the step S4 of eliminating the data that do not meet the requirement includes eliminating the data that the engine water temperature is lower than 70 degrees Celsius and eliminating the data that the altitude is higher than 1700 m.
5. The method of claim 4, wherein in step S5, the cumulative fuel consumption of the fuel consumption window satisfies the following formula:
FC(t 2,i )-FC(t 1,i )≥FC WHTC
FC(t 2,i -Δt)-FC(t 1,i )＜FC WHTC ≤FC(t 2,i )-FC(t 1,i )；
in the formula, FC (t) is the accumulated oil consumption from the initial point of the test to time t, and Δ t is the data sampling period.
6. The method of claim 5, wherein the NOx emission in the PEMS test of the heavy-duty diesel vehicle is calculated by the following formula in step S6:
7. The method of claim 6, wherein in step S6, the window average fuel consumption rate is a window total fuel consumption to window time.
8. The method of claim 7, wherein in step S7, if the effective window ratio is lower than 50%, the window average specific power threshold is adjusted downward by 1% until the effective window ratio is not lower than 50%; if the window average specific power threshold is reduced to 10%, the effective window proportion is still lower than 50%, and the acquisition result is invalid.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211397718.XA CN115655730A (en) | 2022-11-09 | 2022-11-09 | Method for calculating NOx emission in PEMS test of heavy-duty diesel vehicle |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211397718.XA CN115655730A (en) | 2022-11-09 | 2022-11-09 | Method for calculating NOx emission in PEMS test of heavy-duty diesel vehicle |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115655730A true CN115655730A (en) | 2023-01-31 |
Family
ID=85015614
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211397718.XA Pending CN115655730A (en) | 2022-11-09 | 2022-11-09 | Method for calculating NOx emission in PEMS test of heavy-duty diesel vehicle |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115655730A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116127616A (en) * | 2023-04-19 | 2023-05-16 | 中汽研汽车检验中心(昆明)有限公司 | Real-time monitoring method and system for nitrogen oxide tail gas emission of diesel vehicle road |
| CN116771477A (en) * | 2023-06-20 | 2023-09-19 | 中国环境科学研究院环境技术工程有限公司 | Heavy diesel vehicle NOx emission statistical method and system |
-
2022
- 2022-11-09 CN CN202211397718.XA patent/CN115655730A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116127616A (en) * | 2023-04-19 | 2023-05-16 | 中汽研汽车检验中心(昆明)有限公司 | Real-time monitoring method and system for nitrogen oxide tail gas emission of diesel vehicle road |
| CN116771477A (en) * | 2023-06-20 | 2023-09-19 | 中国环境科学研究院环境技术工程有限公司 | Heavy diesel vehicle NOx emission statistical method and system |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN115655730A (en) | Method for calculating NOx emission in PEMS test of heavy-duty diesel vehicle | |
| CN108343497B (en) | System and method for rapidly diagnosing aging failure of SCR system of diesel vehicle | |
| CN109613905B (en) | Method and device for dynamically identifying actual operation high-oil-consumption severe working condition of heavy commercial vehicle | |
| CN111598424A (en) | Emission calculation method based on remote monitoring data of heavy-duty diesel vehicle | |
| CN101886940A (en) | System and method for detecting energy consumption and emission of hybrid electric vehicle | |
| CN108682156B (en) | Method for dynamically monitoring urban traffic emission pollution condition based on taxi GPS data | |
| CN113806675B (en) | NOx emission and oil consumption characteristic analysis method | |
| CN113158125B (en) | Diesel vehicle NOx emission evaluation method based on Internet of vehicles | |
| CN101963800A (en) | Remote real-time monitoring system and monitoring method for diesel vehicle road emission | |
| CN114991922B (en) | Real-time early warning method for exceeding of NOx emission of vehicle | |
| CN205016045U (en) | Car carbon discharges detecting system | |
| CN108763643B (en) | Regional motor vehicle emission factor calculation method | |
| CN110966092B (en) | Method for remotely confirming vehicle emission factor based on PEMS test rule and OBD data | |
| CN110608893A (en) | Vehicle emission testing method and device | |
| CN111122171A (en) | Multi-source heterogeneous data correlation analysis method for diesel vehicle and diesel engine multiple emission detection method based on VSP working condition | |
| CN115876484B (en) | System and method for testing actual road conditions and simulating working conditions of heavy whole vehicle | |
| CN114001989B (en) | Single vehicle air conditioner energy consumption prediction method and prediction device based on working condition recognition | |
| CN111157049A (en) | System and method for rapidly evaluating aging performance of SCR (selective catalytic reduction) postprocessor of diesel vehicle | |
| CN113743715A (en) | Fuel consumption and NOx emission evaluation method based on actual working conditions of Internet of vehicles heavy duty vehicles | |
| Hung et al. | A modal approach to vehicular emissions and fuel consumption model development | |
| CN117079459A (en) | Method and system for constructing traffic flow velocity dense energy spectrum of hybrid automatic driving | |
| CN112730737A (en) | Emission calculation method based on non-road mobile machinery remote monitoring data | |
| CN114755025B (en) | Oil-saving and carbon-reducing evaluation method based on remote online monitoring of fuel oil cleaning synergist | |
| Walkowicz et al. | Coca-Cola refreshments class 8 diesel electric hybrid tractor evaluation: 13-month final report | |
| Kugler et al. | Real-world driving, energy demand and emissions of electrified vehicles |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |