Method for reproducing and simulating road PEMS test
By installing PEMS equipment on a rotating test bench and simulating the road spectrum of the testing center, the discrepancy between the road PEMS preliminary test and certification test results was solved, achieving accurate preliminary testing, improving the certification pass rate, and saving costs and time.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- GUANGXI YUCHAI MASCH CO LTD
- Filing Date
- 2025-12-31
- Publication Date
- 2026-05-08
AI Technical Summary
In the existing technology, there is a significant discrepancy between the road PEMS preliminary test results of vehicle manufacturers or engine manufacturers and the certification test results of testing centers, resulting in certification failure or passing the retest. This makes it impossible to accurately evaluate the certification results of testing centers, increasing certification costs and time.
A PEMS device is installed on a rotating test bench to acquire data from the testing center, convert it into test data suitable for the test bench, plot test curves, import it into the control console computer, simulate the vehicle undergoing PEMS testing on the rotating test bench, reproduce the road spectrum from the testing center, and achieve accurate preliminary testing of the vehicle.
It enables accurate preliminary testing before vehicle PEMS certification testing, improves the comparability and accuracy of results, reduces certification costs and time, increases the pass rate, provides a basis for improvement, and saves testing costs and time.
Smart Images
Figure CN121994503A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to PEMS testing of vehicles, and more specifically, to a method for reproducing and simulating road PEMS testing. Background Technology
[0002] Vehicle manufacturers developing new models need to apply for environmental protection and certification, among which road PEMS certification is mandatory. Road PEMS certification primarily tests whether exhaust emissions meet the standards of GB 17691-2018 "Limits and Test Methods for Pollutant Emissions from Heavy-Duty Diesel Vehicles (China VI)" (referred to as the China VI regulation). Currently, before conducting road PEMS certification for a vehicle, the vehicle manufacturer or engine manufacturer conducts a preliminary road PEMS test using their own PEMS equipment. Only if the emission results (mainly NOx, CO, PN, or THC emission values) of the preliminary test are qualified will the vehicle be submitted to the testing center for road PEMS certification. However, the following situation exists at present: The vehicle manufacturer or engine manufacturer conducts preliminary road PEMS tests and the emissions results are qualified, but when the vehicle is delivered to the testing center for road PEMS certification, the emissions results are unqualified; or, the testing center conducts road PEMS certification and the emissions results are unqualified. The emissions results are fed back to the vehicle manufacturer or engine manufacturer, and the vehicle manufacturer or engine manufacturer uses its own PEMS equipment to re-test the road PEMS. Sometimes the re-test results are qualified.
[0003] This shows a significant discrepancy between the emissions results from the road PEMS baseline test and the certification test from the testing center. The different operating conditions (driving route, altitude, vehicle speed, engine speed, driver behavior, etc.) result in differences in vehicle speed, torque, and exhaust flow. Figure 1 For vehicle speed comparison chart, Figure 2 For altitude comparison chart, Figure 3 For exhaust flow comparison chart, Figure 4 The torque comparison charts show a significant difference between the two, leading to different results. Furthermore, the greater the difference in operating conditions, the greater the difference in emission results, making the road PEMS test results less reliable for evaluating the certification results from the testing center. Summary of the Invention
[0004] The technical problem to be solved by the present invention is to provide a method for reproducing and simulating road PEMS tests to address the shortcomings of the existing technology. This method enables accurate and effective preliminary PEMS testing before vehicle road PEMS certification testing, saving automobile manufacturers certification costs and time.
[0005] The present invention discloses a method for reproducing and simulating road PEMS tests, the method comprising the following steps: Step 1: Install the PEMS equipment on the rotating drum stand; Step 2: Obtain data collected by the PEMS testing laboratory at the testing center; Step 3: Convert the data collected by the PEMS test center into test data suitable for the rotating drum test bench; Step 4: Plot the test curve based on the test data; Step 5: Import the test curve into the control console computer of the rotating drum test bench; Step 6: Conduct pre-test inspections on the vehicle to be tested, and drive the vehicle to be tested onto the rotating test bench; Step 7: Perform PEMS testing on the test vehicle using a rotating bench according to the test curve. Step 8: After the test is completed, process, analyze, and export the PEMS test data and report the results.
[0006] Preferably, the data collected by the PEMS test at the testing center includes altitude and vehicle speed data.
[0007] Preferably, in step three, the altitude and vehicle speed data are converted into slope and corresponding vehicle speed data.
[0008] Preferably, in step four, the test time is allocated according to the road conditions that the vehicle needs to travel on, and time-speed curves and time-gradient curves are plotted based on the test time, gradient, and corresponding vehicle speed data.
[0009] Preferably, in step five, the time-slope curve is imported into the control computer of the swivel test bench to set the road spectrum parameters of the swivel test bench. The control system of the swivel test bench outputs the resistance of the swivel test bench according to the time-slope curve to simulate the driving resistance experienced by the wheel hub during vehicle road testing.
[0010] Preferably, in step seven, the vehicle under test is controlled to drive on the rotating test bench according to the time-speed curve.
[0011] Beneficial effects The advantages of this invention are: 1. Based on the data collected by the PEMS testing center, this invention transfers the PEMS testing of vehicles to a rotating test bench, realizing accurate and effective PEMS preliminary testing before the vehicle road PEMS certification test. The preliminary test results are comparable, improving the accuracy and effectiveness of the preliminary test results evaluation. Vehicles are only delivered after the preliminary test results are passed and have a large margin, thereby increasing the certification pass rate, saving car manufacturers certification costs and time, and helping car manufacturers to quickly seize the market.
[0012] 2. This invention reproduces the PEMS certification road spectrum of the testing agency on the rotating test bench, and reproduces the parameters and performance parameters of each working condition. This not only facilitates accurate analysis and finding the cause, providing an accurate basis for improvement measures and helping to meet the standards in the next test, but also allows for arbitrary switching of test roads by setting vehicle speed and gradient. This eliminates the need to conduct tests on roads with various terrains in remote locations, saving a lot of time and costs for testing. Attached Figure Description
[0013] Figure 1 A comparison chart of vehicle speeds for road PEMS baseline testing and testing center certification testing; Figure 2 An elevation comparison chart for road PEMS baseline testing and testing center certification testing; Figure 3 A comparison chart of exhaust flow rates for road PEMS baseline testing and testing center certification testing; Figure 4 A comparison chart of torque values from road PEMS baseline testing and testing center certification testing; Figure 5 This is a schematic diagram of the method for reproducing and simulating road PEMS tests according to the present invention; Figure 6 This is a schematic diagram of the time-vehicle speed curve and the time-gradient curve of the present invention; Figure 7 This is a comparison chart of vehicle speeds based on the method of this invention and those obtained through certification testing by a testing center; Figure 8 This is a comparison chart of rotational speeds based on the method of this invention and those obtained through certification testing by a testing center; Figure 9 This is a comparison chart of altitude results based on the method of this invention and those obtained through certification testing by a testing center; Figure 10 This is a comparison chart of exhaust flow rates based on the method of this invention and those obtained through certification testing by a testing center; Figure 11 This is a comparison chart of torque measured using the method of this invention and the torque measured by a testing center certification test. Figure 12 This is a comparison chart of torque distribution based on the method of this invention and the torque distribution obtained from the certification test conducted by the testing center; Figure 13 This is a comparison chart of the PN distribution based on the method of this invention and the certification test results from the testing center. Detailed Implementation
[0014] The present invention will be further described below with reference to embodiments, but this does not constitute any limitation on the present invention. Any limited modifications made by any person within the scope of the claims of the present invention are still within the scope of the claims of the present invention. See Figure 5The present invention provides a method for reproducing and simulating road PEMS tests, the method comprising the following steps: Step 1: Install the PEMS equipment on the swivel test bench, so that the road PEMS test is carried out on the swivel test bench.
[0015] Step 2: Connect and communicate with the testing center to obtain the data collected by the PEMS test. Then, extract the data from the PEMS test provided by the testing center, mainly the altitude and vehicle speed data.
[0016] Step 3: Convert the data collected by the PEMS testing center into test data suitable for the rotating test bench. Specifically, convert the extracted altitude and vehicle speed data into slope and corresponding vehicle speed data.
[0017] Step 4: Plot the gradient and its corresponding vehicle speed data into time-vehicle speed and time-gradient curves. For example... Figure 6 As shown, time is plotted on the horizontal axis, and vehicle speed and gradient are plotted on the vertical axes. This reproduces the road spectrum of the testing agency's PEMS test. Subsequent PEMS tests are then conducted on a rotating test bench according to these curves, enabling the reproduction of the testing agency's road PEMS certification test and facilitating accurate analysis of various operating conditions, performance, and causes during certification.
[0018] Specifically, the test vehicles are divided into urban, suburban, and highway operating conditions according to their model, purpose, and China VI emission standards. Therefore, the test time on the test bench is also allocated according to this operating condition ratio. The time-speed and time-gradient curves are calibrated based on this test time. This ensures that the speed requirements for urban, suburban, and highway operating conditions of the test vehicles can be tested on the test bench. Furthermore, the time-gradient curve also reflects the uphill and downhill operating conditions of the test vehicles; the gradient is calculated based on the altitude, and the road gradient data is set in the gradient parameters of the test bench, thus replicating the road profile onto the test bench. Moreover, harsh operating conditions can be set on the test bench, such as full-load resistance, long uphill slopes, long downhill slopes, and frequent uphill and downhill slopes. This solves the problem of limited local road verification intensity and inability to meet the extreme performance verification requirements of the engine's core system, achieving extreme road verification of the engine.
[0019] Therefore, the curve allows the test vehicle to set its speed and gradient at will, and switch test roads at will. This eliminates the need to travel to remote places, such as high-altitude areas, long uphill or downhill areas, or other terrains with various topographical features. It solves the problem of local roads lacking extreme road conditions such as long uphill, long downhill, or frequent uphill and downhill sections, saving a lot of time and costs for testing.
[0020] Step 5: Import the "Time-Gradient Curve" into the control computer of the swivel test bench to set the swivel's road profile parameters. The swivel control system will automatically convert the time-gradient curve into swivel resistance. Additionally, import the "Time-Speed Curve" into the control computer. This road profile curve will be displayed on the screen in the swivel test chamber to guide the driver to maintain the current vehicle speed.
[0021] Step Six: Vehicle Testing Preparations: First, inspect the test vehicle to ensure it is in good working order and free of faults; add sufficient fuel (or natural gas), urea, and coolant to the test vehicle; ensure adequate tire pressure; perform parking regeneration. Then, drive the vehicle onto the wheel slewing platform and secure it, etc.
[0022] Step 7: Warm up the PEMS equipment and the test bench. After preparation, the driver drives the vehicle according to the "Time-Speed Curve" on the screen, and the test engineer operates the PEMS equipment to conduct emissions testing. Throughout the entire process, the PEMS equipment synchronously detects and collects vehicle exhaust emissions, achieving the reproduction or simulation of road PEMS testing under the same load. Through this experiment, the road PEMS testing conducted at the testing center and the PEMS testing conducted on the rotating test bench are highly comparable.
[0023] Step 8: Test completion. The PEMS equipment processes, analyzes, and exports the PEMS test data, generating a report. (Specific details are as follows...) Figure 7 , Figure 8 , Figure 9 , Figure 10 , Figure 11 , Figure 12 , Figure 13 As shown in the figure, the two are very similar and highly comparable.
[0024] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention, and these will not affect the effectiveness of the implementation of the present invention or the practicality of the patent.
Claims
1. A method for reproducing and simulating road PEMS tests, characterized in that, The method includes the following steps: Step 1: Install the PEMS equipment on the rotating drum stand; Step 2: Obtain data collected by the PEMS testing laboratory at the testing center; Step 3: Convert the data collected by the PEMS test center into test data suitable for the rotating drum test bench; Step 4: Plot the test curve based on the test data; Step 5: Import the test curve into the control console computer of the rotating drum test bench; Step 6: Conduct pre-test inspections on the vehicle to be tested, and drive the vehicle to be tested onto the rotating test bench; Step 7: Perform PEMS testing on the test vehicle using a rotating bench according to the test curve. Step 8: After the test is completed, process, analyze, and export the PEMS test data and report the results.
2. The method for reproducing and simulating road PEMS tests according to claim 1, characterized in that, The data collected by the PEMS test at the testing center includes altitude and vehicle speed data.
3. The method for reproducing and simulating road PEMS tests according to claim 2, characterized in that, In step three, the altitude and vehicle speed data are converted into slope and corresponding vehicle speed data.
4. The method for reproducing and simulating road PEMS tests according to claim 3, characterized in that, In step four, test time is allocated according to the road conditions required for the vehicle to travel, and time-speed curves and time-gradient curves are plotted based on the test time, gradient, and corresponding vehicle speed data.
5. The method for reproducing and simulating road PEMS tests according to claim 4, characterized in that, In step five, the time-slope curve is imported into the control computer of the swivel test bench to set the road spectrum parameters of the swivel test bench. The control system of the swivel test bench outputs the resistance of the swivel test bench according to the time-slope curve to simulate the driving resistance experienced by the wheel hub during the vehicle road test.
6. The method for reproducing and simulating road PEMS tests according to claim 4, characterized in that, In step seven, the vehicle under test is controlled to drive on the rotating test bench according to the time-vehicle speed curve.