Vehicle gear shifting test method and system based on on-board diagnostic interface timing data

Abstract

This invention provides a vehicle gear shifting test method and system based on timing data from an on-board diagnostic interface. The method includes: signal acquisition, data processing, establishment of a steady-state speed ratio range, identification of candidate gear shift ranges, gear shift determination, test compliance determination, and test report generation. The system includes modules corresponding to each step. This vehicle gear shifting test method based on timing data from an on-board diagnostic interface is used to achieve automatic gear shifting interpretation and test analysis of the vehicle under test under cyclic testing. By introducing speed ratio characterization parameters and steady-state speed ratio ranges, gear shifting identification is established on the basis of changes in power transmission state, thereby improving the stability of gear-related signal identification through an intermediate characterization layer. This test method and system can adapt to different test objects and can automatically generate test reports.

Description

Technical Field

[0001] This invention relates to the field of vehicle testing, and specifically to a vehicle shifting test method and system based on timing data from an on-board diagnostic interface. Background Technology

[0002] During vehicle emissions testing, vehicle performance testing, and regulatory compliance verification, testers typically need to analyze the gear shifting behavior of the vehicle under test during the test cycle to determine whether gear shifting occurred, when it occurred, the duration of the shift, the type of shift, whether the timing of the shift met the preset test requirements, and whether manual verification was required.

[0003] Existing technologies mainly include: directly reading the gear position signal provided by the vehicle controller or transmission controller; using external hardware such as GPS, video, acceleration sensor, and speed sensor for auxiliary identification; and relying on test personnel to manually view engine speed curves, vehicle speed curves, and video data to determine the shift boundary.

[0004] The aforementioned existing technologies suffer from several drawbacks, including insufficient versatility, high cost of external equipment, complex test deployment, low efficiency of manual interpretation, and poor result consistency. Particularly in actual testing, the gear-related signals that the tested vehicle can reliably provide through the on-board diagnostic interface vary depending on the vehicle model, communication permissions, and control architecture. Furthermore, even when relying solely on data acquired through the on-board diagnostic interface for gear shifting judgment, issues remain, such as limited sampling frequency, uneven sampling time intervals, outliers, transient fluctuations, and localized noise. Moreover, different types of transmissions exhibit variations in shift duration, gear ratio change patterns, and dynamic response characteristics, further complicating the stable acquisition of gear-related signals.

[0005] Therefore, there is still a need for an automated analysis scheme for vehicle testing scenarios, which can automatically identify, analyze, judge, and report the shifting behavior during the testing process using only the basic timing data provided by the on-board diagnostic interface of the vehicle under test, without relying on the gear position signal of the vehicle under test and preferably without connecting external sensors for shift recognition. Summary of the Invention

[0006] This invention is made to solve the above-mentioned problems, and aims to provide a vehicle shifting test method and system based on timing data from the vehicle diagnostic interface.

[0007] This invention provides a vehicle shifting test method based on on-board diagnostic interface timing data. This method is used for automatic identification of shifting events, determination of shifting timing, and automatic generation of test reports during vehicle cyclic testing. Vehicle cyclic testing includes at least one of the following: vehicle emissions cyclic testing, vehicle power or economy testing, proving ground cyclic operating condition testing, and vehicle shifting compliance testing. The shifting test method includes the following steps: a signal acquisition step, acquiring measured timing data of the vehicle under test during cyclic testing through at least the on-board diagnostic interface of the vehicle under test, including engine speed signal, vehicle speed signal, and time signal acquired through the on-board diagnostic interface of the vehicle under test; a data processing step, preprocessing the measured timing data, calculating the engine speed change rate, vehicle speed change rate, and speed ratio characterization parameters for power transmission based on the preprocessed engine speed and vehicle speed signals, and identifying steady-state driving segments that meet preset steady-state conditions from the preprocessed measured timing data; and a steady-state speed ratio interval establishment step, establishing a steady-state speed ratio interval for the steady-state driving segments. The test involves analyzing the speed ratio characterization parameters of a gear shift segment and establishing multiple steady-state speed ratio intervals to represent different stable power transmission states during cyclic testing. A candidate shift interval identification step searches the pre-processed measured time-series data for the migration process of the speed ratio characterization parameters between different steady-state speed ratio intervals. During this migration, when the engine speed change rate exceeds a preset adaptive speed threshold and the vehicle speed change rate meets the continuity constraint, the corresponding time interval is identified as a candidate shift interval, and false shift events caused by sampling anomalies, local noise, or data spikes are filtered out. A shift determination step extracts shift feature parameters for each candidate shift interval and outputs a shift determination result based on these parameters. A test compliance determination step determines the characterization time of the shift event based on the shift determination result, extracts the corresponding vehicle speed value, compares it with preset shift timing determination rules, and outputs a test compliance determination result. A test report generation step generates a test report based on the shift determination result and the test compliance determination result.

[0008] The vehicle shifting test method based on vehicle diagnostic interface timing data provided by the present invention may also have the following features: in the data processing step, the preprocessing of the measured timing data includes: time synchronization, outlier removal, and smoothing filtering of the measured timing data, and calculating the engine speed change rate and vehicle speed change rate based on adjacent sampling times. The speed ratio characterization parameter can be the direct ratio of the engine speed signal and the vehicle speed signal, or it can be an equivalent speed ratio parameter obtained after processing the direct ratio sequence through moving average, weighted smoothing, or median filtering. When the vehicle speed signal is lower than the preset vehicle speed lower limit threshold, the measured timing data of that sampling time is removed from the data set used to establish the steady-state speed ratio interval.

[0009] The vehicle shifting test method based on vehicle diagnostic interface timing data provided by this invention may also have the following feature: In the data processing step, the preset steady-state condition is: within a continuous preset time period, the absolute value of the engine speed change rate, the absolute value of the vehicle speed change rate, and the fluctuation range of the speed ratio characterization parameter of the tested vehicle do not exceed the corresponding preset threshold range. The preset threshold corresponding to the absolute value of the engine speed change rate is an adaptive speed threshold, which is dynamically adjusted during cyclic testing. The adjustment process includes: calculating the standard deviation σn of the engine speed change rate in a steady-state driving segment; calculating the speed ratio fluctuation rate σr of the speed ratio characterization parameter in the steady-state driving segment; calculating the center value difference ΔC between adjacent steady-state speed ratio intervals; and adjusting the adaptive speed threshold θadp according to the sampling period Δt, the standard deviation σn of the engine speed change rate, the speed ratio fluctuation rate σr, and the center value difference ΔC between adjacent intervals. The formula for calculating the adaptive speed threshold θadp is: θadp = α·σn + β·σr / Δt + γ·ΔC / Tavg; where Tavg... The average duration of historical gear shift samples is α, β, and γ, which are weighting coefficients. These weighting coefficients are obtained by correcting historical test samples, manually reviewed samples, or by pre-setting according to vehicle type, transmission type, and test item type.

[0010] The vehicle shift test method based on vehicle diagnostic interface timing data provided by the present invention may also have the following features: in the shift determination step, the shift characteristic parameters include the steady-state speed ratio range before shift, the steady-state speed ratio range after shift, the shift duration, the amplitude of engine speed change, the peak value of engine speed change rate, the vehicle speed change rate, and the deviation of the speed ratio characterization parameters from the steady-state speed ratio range.

[0011] The vehicle shift testing method based on on-board diagnostic interface timing data provided by this invention may also have the following features: In the shift determination step, the shift determination result includes a shift event and the corresponding determination confidence level. After obtaining the determination confidence level of the shift event, a review is performed, including: when the determination confidence level is higher than a preset high confidence threshold, the corresponding shift event is included in the test compliance determination; when the determination confidence level is lower than a preset low confidence threshold, a review mark is generated, and the occurrence time of the corresponding shift event, the boundary of the shift candidate interval, and the shift feature parameters are marked in the test report; when the determination confidence level is within the preset confidence threshold range, the corresponding shift event is marked as an intermediate confidence event, and automatic determination or manual review is selected according to the test item requirements.

[0012] The vehicle shifting test method based on vehicle diagnostic interface timing data provided by this invention may also have the following features: In the test compliance determination step, the preset shifting timing determination rule includes the target shifting speed range. After identifying a shifting event, the representation time of the shifting event is determined, and the vehicle speed value corresponding to the representation time is extracted. If the vehicle speed value falls within the target shifting speed range, a compliant shifting result is output; if the vehicle speed value is lower than the lower limit of the target shifting speed range or higher than the upper limit of the target shifting speed range, an illegal shifting result is output, and the shifting event number, representation time, corresponding vehicle speed, target range, and out-of-tolerance direction are recorded in the test report.

[0013] The vehicle shifting test method based on vehicle diagnostic interface timing data provided by the present invention may also have the following features: the continuity constraint conditions include: the difference in the rate of change of vehicle speed between adjacent sampling points does not exceed the corresponding preset threshold, there are no isolated spikes in the candidate shifting interval, the number of times the sign of the rate of change of vehicle speed changes in the candidate shifting interval does not exceed the preset number, and when the speed ratio characterization parameter undergoes a steady-state speed ratio interval shift, but the rate of change of vehicle speed does not meet the continuity constraint conditions, the corresponding interval is judged as a pseudo shifting event and is removed.

[0014] This invention also provides a vehicle shifting test system based on on-board diagnostic interface timing data, used for performing the above-mentioned test method, characterized by: a signal acquisition module, used to acquire measured timing data of the vehicle under test during cyclic testing at least through the on-board diagnostic interface of the vehicle under test; a data processing module, used to preprocess the measured timing data, calculate the engine speed change rate, vehicle speed change rate, and speed ratio characterization parameters for characterizing the power transmission state based on the preprocessed engine speed signal and vehicle speed signal, and identify steady-state driving segments that meet preset steady-state conditions from the preprocessed data; a steady-state speed ratio interval establishment module, used to analyze the speed ratio characterization parameters of the steady-state driving segments and establish multiple steady-state speed ratio intervals; and a candidate shifting interval identification module, used to identify the candidate shifting intervals from the preprocessed measured timing data. The search module examines the migration process of the speed ratio characterization parameters between different steady-state speed ratio intervals. During this migration, when the engine speed change rate exceeds a preset adaptive speed threshold and the vehicle speed change rate meets the continuity constraint, the corresponding time interval is identified as a candidate shift interval, and false shift events caused by sampling anomalies, local noise, or data spikes are filtered out. The shift determination module extracts shift feature parameters for each candidate shift interval and outputs the shift determination result based on these parameters. The test compliance determination module determines the characterization time of the shift event based on the shift determination result, extracts the corresponding vehicle speed value, compares it with the preset shift timing determination rule, and outputs the test compliance determination result. The test report generation module generates a test report based on the shift determination result and the test compliance determination result.

[0015] Compared with the prior art, the functions and effects of the present invention include:

[0016] This invention provides a vehicle shifting test method based on on-board diagnostic interface timing data. This method enables automatic interpretation and test analysis of the vehicle under test during cyclic testing. By introducing speed ratio characterization parameters and steady-state speed ratio ranges, shifting identification is based on changes in power transmission state, rather than directly relying on a single fixed threshold, direct gear signals, or manual experience. This intermediate characterization layer improves the stability and consistency of gear-related signal identification. The test method and the test system used to perform this method are adaptable to different test objects and can automatically generate test reports. Attached Figure Description

[0017] Figure 1 This is a flowchart of a vehicle shifting test method based on on-board diagnostic interface timing data in an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of the speed ratio range migration principle in an embodiment of the present invention;

[0019] Figure 3 This is a flowchart of the confidence level classification and verification process in the gear shift determination process of the present invention.

[0020] Figure 4 This is a schematic diagram of gear shift feature extraction in an embodiment of the present invention.

[0021] Figure 5 This is a structural diagram of a vehicle shifting test system based on timing data from an on-board diagnostic interface, as described in an embodiment of the present invention.

[0022] In the diagram: 1. Signal acquisition module; 2. Data processing module; 3. Steady-state speed ratio range establishment module; 4. Candidate shift range identification module; 5. Shift determination module; 6. Test compliance determination module; 7. Test report generation module; 10. System. Detailed Implementation

[0023] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0024] To make the technical means, creative features, objectives and effects of the present invention easy to understand, the following embodiments, in conjunction with the accompanying drawings, specifically illustrate the vehicle shifting test method and system based on on-board diagnostic interface timing data of the present invention.

[0025] This embodiment provides a vehicle shift testing method based on timing data from an on-board diagnostic interface. It is used to automatically identify shift events, determine shift timing, and automatically generate test reports during vehicle cyclic testing. Vehicle cyclic testing refers to a process executed according to a preset speed-time curve, enterprise testing specifications, proving ground cyclic conditions, or shift timing rules. This includes at least one of the following: vehicle emissions cyclic testing, vehicle power or economy testing, proving ground cyclic condition testing, and vehicle shift compliance testing. The testing method in this embodiment does not directly measure emissions or vehicle performance indicators, but rather automatically interprets shift events, shift times, shift durations, shift types, and shift event compliance during the testing process.

[0026] Figure 1 This is a flowchart of the test method, such as... Figure 1 As shown: This test method includes the following steps S1-S7.

[0027] S1, Signal Acquisition Step: At least the measured timing data of the vehicle under test during the cyclic test are acquired through the on-board diagnostic interface (OBD, abbreviation for On-Board Diagnostics) of the vehicle under test, including engine speed signal, vehicle speed signal and time signal.

[0028] The testing method in this embodiment does not rely on the gear position signal directly output by the vehicle under test, nor does it require the connection of an external sensor for gear shift recognition. In the preferred embodiment, the gear shift test analysis can be completed using only the engine speed, vehicle speed, and time data obtained through the on-board diagnostic interface.

[0029] In this embodiment, the following test samples and boundary conditions are provided, as shown in Table 1 below:

[0030] Table 1

[0031]

[0032] S2, Data Processing Step: Preprocess the measured time series data, calculate the engine speed change rate, vehicle speed change rate, and speed ratio characterization parameters based on the preprocessed data, and identify steady-state driving segments that meet the preset steady-state conditions from the preprocessed data.

[0033] Specifically, the preprocessing of the measured time-series data includes: time synchronization, outlier removal, and smoothing filtering. The rate of change of engine speed and vehicle speed are calculated based on adjacent sampling times. Based on the preprocessed engine speed and vehicle speed signals, a speed ratio characterization parameter R(i) is constructed to represent the power transmission state. This speed ratio characterization parameter can be the direct ratio of engine speed to vehicle speed, or an equivalent speed ratio parameter obtained after processing the direct ratio sequence through moving average, weighted smoothing, median filtering, etc. Preferably, R(i) = n(i) / v(i), where n(i) is the engine speed at the i-th sampling point, and v(i) is the vehicle speed at the i-th sampling point. When the vehicle speed is lower than a preset lower vehicle speed threshold, the speed ratio characterization parameter corresponding to that sampling point may not be calculated, or the sampling point may be removed from the dataset used to establish the steady-state speed ratio range.

[0034] In this step, the preset steady-state conditions are: within a continuous preset time period, the absolute value of the rate of change of the engine speed of the tested vehicle is less than its corresponding adaptive speed threshold, the absolute value of the rate of change of the vehicle speed is less than its corresponding preset vehicle speed threshold, and the fluctuation range of the speed ratio characterization parameter does not exceed its corresponding preset threshold range. Segments that meet the above preset steady-state conditions are identified from the measured time-series data throughout the entire test process and are thus considered steady-state driving segments.

[0035] Furthermore, the adaptive speed threshold can be dynamically adjusted during cyclic testing based on indicators such as the standard deviation of the engine-specific rate of change, the volatility of the speed ratio characterization parameter, the difference in the center values ​​of adjacent steady-state speed ratio intervals, the sampling period, and the historical shift duration. The adjustment process includes:

[0036] Calculate the standard deviation σn of the rate of change of engine speed in a steady-state driving segment;

[0037] Calculate the speed ratio fluctuation rate σr of the speed ratio characterization parameter in a steady-state driving segment;

[0038] Calculate the difference ΔC between the center values ​​of adjacent steady-state speed ratio intervals;

[0039] The adaptive speed threshold θadp is adjusted based on the sampling period Δt, the standard deviation of the engine speed change rate σn, the speed ratio fluctuation rate σr, and the difference in center values ​​between adjacent intervals ΔC. The formula for calculating the adaptive speed threshold θadp is as follows:

[0040] θadp = α·σn + β·σr / Δt + γ·ΔC / Tavg;

[0041] Where Tavg is the average duration of historical shift samples, and α, β, and γ are weighting coefficients, which can be obtained through historical test sample calibration, manual review of samples, or preset according to vehicle type, transmission type, and test item type. σr and ΔC can be calculated using normalized values ​​to allow data of different dimensions or amplitude ranges to be used together for threshold adjustment. Tavg can be the average duration of historical shift samples under the same vehicle type, transmission type, or test item, or it can be the average duration of the initial test clamp determined based on manually reviewed samples.

[0042] According to this formula, when the sampling period is long or the steady-state segment fluctuates greatly, θadp increases accordingly to reduce noise-induced false triggering; when the difference between the center values ​​of adjacent steady-state speed ratio intervals is large and the historical shift duration is short, θadp can enhance the response capability to valid shift events. The effect of the adaptive threshold is shown in Table 2 below:

[0043] Table 2

[0044]

[0045] S3, Steady-state speed ratio interval establishment step, analyzes the speed ratio characterization parameters of steady-state driving segments, and establishes multiple steady-state speed ratio intervals.

[0046] Specifically, the steady-state speed ratio interval can be established using methods such as K-means clustering, hierarchical clustering, density clustering, histogram peak identification, or quantile interval division. In this embodiment, the steady-state speed ratio interval does not need to correspond one-to-one with the actual mechanical gear numbers. Through the speed ratio characterization parameters and the steady-state speed ratio interval, an intermediate characterization layer of the power transmission state during the test process is established, thereby providing a state benchmark for subsequent interval migration identification. The establishment results of the steady-state speed ratio interval in this embodiment are shown in Table 3 below:

[0047] Table 3

[0048]

[0049] Figure 2 This is a schematic diagram of the speed ratio range migration principle in this embodiment.

[0050] S4, Candidate shift interval identification steps, such as Figure 2 As shown, the migration process of the speed ratio characterization parameter between different steady-state speed ratio ranges is searched from the preprocessed data to identify candidate shift intervals. Continuity constraints are applied to the vehicle speed change rate in the preprocessed data to filter out pseudo shift events caused by sampling anomalies, local noise, or data spikes.

[0051] Specifically, such as Figure 2As shown, the candidate shift intervals satisfy the following conditions: the speed ratio characterization parameter continuously deviates from the first steady-state speed ratio interval, enters the second steady-state speed ratio interval after passing through the unstable transition region, the engine speed change rate exceeds the adaptive speed threshold, and the vehicle speed change rate satisfies the continuity constraint condition. By identifying the above interval transition process, the time intervals in which shift events may occur can be found from the entire test process, i.e., the candidate shift intervals.

[0052] The continuity constraints include: the difference in vehicle speed change rate between adjacent sampling points does not exceed a corresponding preset threshold; there are no isolated spikes within the candidate shift interval; and the number of sign changes in the vehicle speed change rate within the candidate shift interval does not exceed a preset number. When the speed ratio characterization parameter undergoes a steady-state speed ratio interval shift, but the vehicle speed change rate does not meet the continuity constraints, the corresponding interval is identified as a pseudo-shift event and eliminated. Therefore, this embodiment can avoid misjudgments caused by uneven sampling intervals, local data anomalies, or transient noise in the on-board diagnostic interface.

[0053] Furthermore, this embodiment improves the adaptability and robustness of recognition for different tested vehicles and transmission types by combining steady-state speed ratio range migration, adaptive speed threshold, and vehicle speed change rate continuity constraints. Existing technologies relying solely on fixed speed or vehicle speed thresholds struggle to adapt to differences in data noise and dynamic response under varying vehicle models, transmissions, and OBD sampling qualities. This embodiment uses manual verification results as a reference, comparing the recognition results of the fixed speed threshold method with those of this scheme on the same batch of test samples, as shown in Table 4 below:

[0054] Table 4

[0055]

[0056] As can be seen from the examples provided in Table 4, this scheme can reduce false detections and false negatives and improve the consistency of shift boundary positioning by working together through steady-state speed ratio range migration, adaptive threshold and continuity constraints.

[0057] S5, the shift determination step, extracts shift feature parameters for each shift candidate interval, and outputs the shift determination result based on the shift feature parameters.

[0058] Figure 3 This is a flowchart of the confidence level classification and verification process in the gear shift determination process in this embodiment.

[0059] Specifically, such as Figure 3 As shown: This step is divided into S5-1 to S5-6.

[0060] Figure 4 This is a schematic diagram of gear shift feature extraction in this embodiment.

[0061] S5-1, as shown Figure 4 As shown: For each confirmed candidate shift interval, the following shift feature parameters are extracted: steady-state speed ratio interval before shift, steady-state speed ratio interval after shift, shift duration, engine speed change amplitude, peak engine speed change rate, vehicle speed change rate, and deviation of the speed ratio characterization parameters from the steady-state speed ratio interval.

[0062] S5-2 outputs the shift event, shift type label, and corresponding decision confidence score based on the aforementioned shift characteristic parameters. The shift type label can include upshift, downshift, coasting downshift, rapid acceleration shift, compliant shift, and non-compliant shift. The output shift type label can be expanded or reduced according to specific test items.

[0063] This embodiment provides a feature output example for a single gear shift event, as shown in Table 5 below:

[0064] Table 5

[0065]

[0066] S5-3 compares the confidence level of the shift event with a preset confidence threshold range.

[0067] In this embodiment, the high confidence threshold is set to 0.80, and the low confidence threshold is set to 0.60. These thresholds can be adjusted according to test requirements, vehicle type, transmission type, or historical manually reviewed samples.

[0068] S5-4A: When the confidence level is greater than or equal to 0.80, the corresponding gear shifting event will be included in the test compliance judgment.

[0069] S5-4B: When the confidence level is lower than 0.60, a verification mark is generated to prevent the system 10 from making forced judgments on events with unclear boundaries, and the corresponding shift event occurrence time, shift candidate interval boundary and shift feature parameters are marked in the test report.

[0070] S5-4C: When the confidence level is within the range of [0.6, 0.8), the corresponding shift event is marked as an intermediate confidence level event, and automatic judgment or manual review is selected according to the test item requirements.

[0071] S5-5, write the shift event boundary and the extracted shift feature parameters.

[0072] S5-6 outputs the gear shift determination result.

[0073] S6, Test compliance determination step: Determine the representation moment of the shift event based on the shift determination result, extract the preprocessed data corresponding to that moment, compare it with the preset shift timing determination rule, and output the test compliance determination result.

[0074] The preset shift timing determination rules can be established based on national standards, industry standards, enterprise testing specifications, vehicle development verification specifications, test track cycle conditions, test task books, or internal verification rules, including the target shift speed range.

[0075] Specifically, this step includes: after identifying a shift event, determining the representation time of the shift event, and extracting the vehicle speed value corresponding to the representation time. If the vehicle speed value falls within the target shift speed range, a compliant shift result is output; if the vehicle speed value is lower than the lower limit of the target shift speed range or higher than the upper limit of the target shift speed range, an illegal shift result is output, and the shift event number, representation time, corresponding vehicle speed, target range, and out-of-tolerance direction are recorded in the test report.

[0076] In this embodiment, it is assumed that the target shift speed range for a certain test item is set to V1-V2, i.e., 40-45 km / h. After identifying the shift event, the vehicle speed vj corresponding to the shift characterization time is compared: if vj < 40 km / h, it is determined to be an early shift; if vj > 45 km / h, it is determined to be a delayed shift; if 40 ≤ vj ≤ 45 km / h, it is determined to meet the preset shift timing rules, as shown in Table 6 below:

[0077] Table 6

[0078]

[0079] This compliance determination step can directly output results for early shifting, delayed shifting, or compliance, improving the efficiency of test report generation.

[0080] S7, Test Report Generation Step: Generate a test report based on the shift judgment result and the test compliance judgment result.

[0081] Specifically, the test report includes fields such as test item name, test cycle number, vehicle number under test, transmission model, total number of shift events, time of occurrence of shift events, steady-state speed ratio range before and after shift, shift duration, shift type label, judgment confidence level, test compliance judgment result, number of events requiring review, and boundary information of events requiring manual review.

[0082] Through the aforementioned test reports, testers can directly obtain the identification structure of shifting events during cyclic testing, whether shifting conforms to preset rules, and abnormal events that require manual review, thereby improving the consistency of shifting behavior interpretation and report generation efficiency during vehicle cyclic testing.

[0083] This embodiment also provides a vehicle shift testing system 10 based on timing data from an on-board diagnostic interface. Figure 5 Here is a structural diagram of the test system 10, as follows: Figure 5 As shown, system 10 includes: signal acquisition module 1, data processing module 2, steady-state speed ratio range establishment module 3, candidate shift range identification module 4, shift determination module 5, test compliance determination module 6, and test report generation module 7.

[0084] The signal acquisition module 1 is used to implement the above step S1; the data processing module 2 is used to implement the above step S2; the steady-state speed ratio range establishment module 3 is used to implement the above step S3; the candidate shift range identification module 4 is used to implement the above step S4; the shift determination module 5 is used to implement the above step S5; the test compliance determination module 6 is used to implement the above step S6; and the test report generation module 7 is used to implement the above step S7.

[0085] The role and effects of the embodiments:

[0086] This embodiment presents a vehicle shift testing method based on timing data from the on-board diagnostic interface. This method is used to automatically identify shift events, determine shift timing, and generate test reports during vehicle cyclic testing. By introducing speed ratio characterization parameters and steady-state speed ratio ranges, this method bases shift recognition on changes in power transmission state, rather than directly relying on a single fixed threshold, direct gear signals, or manual experience, thereby improving the stability and consistency of shift recognition.

[0087] The testing method and system in this embodiment do not rely on the gear position signal directly output by the vehicle under test, nor do they require the connection of external sensors for gear shift recognition. In the preferred embodiment, gear shift test analysis can be completed using only the engine speed, vehicle speed and time data obtained through the vehicle diagnostic interface, thus reducing the complexity of test deployment and improving the applicability to different vehicle models in test scenarios.

[0088] This embodiment, through the combined effects of steady-state speed ratio range migration, adaptive speed threshold, and vehicle speed change rate continuity constraint, can reduce false shift events and missed detection events, and improve the recognition robustness under different vehicle types and different transmission types, even when the sampling frequency of the on-board diagnostic interface is limited, the sampling interval is uneven, and there are outliers or local noise.

[0089] This embodiment further utilizes a confidence leveling and review marking mechanism to automatically include high-confidence shift events in the test compliance judgment and mark low-confidence or unclear-boundary events as objects for manual review, thereby avoiding mandatory judgment on uncertain events and improving the traceability of test reports and the credibility of engineering.

[0090] Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A vehicle shifting test method based on on-board diagnostic interface timing data, used for automatic identification of shifting events, determination of shifting timing, and automatic generation of test reports during vehicle cyclic testing, wherein the vehicle cyclic testing includes at least one of vehicle emissions cyclic testing, vehicle power performance or economy testing, proving ground cyclic operating condition testing, and vehicle shifting compliance testing, characterized in that... The shifting test method includes the following steps: The signal acquisition step involves acquiring, at least through the on-board diagnostic interface of the vehicle under test, the measured timing data of the vehicle under test during the cyclic test, including engine speed signal, vehicle speed signal and time signal; The data processing step involves preprocessing the measured time series data, calculating the engine speed change rate, vehicle speed change rate, and speed ratio characterization parameter for power transmission state based on the preprocessed engine speed signal and vehicle speed signal, and identifying steady-state driving segments that meet preset steady-state conditions from the preprocessed measured time series data. The steady-state speed ratio range establishment step involves analyzing the speed ratio characterization parameters of the steady-state driving segment and establishing multiple steady-state speed ratio ranges to represent different stable power transmission states during cyclic testing. The candidate shift interval identification step searches for the migration process of the speed ratio characterization parameter between different steady-state speed ratio intervals from the preprocessed measured time series data. During the migration process, when the engine speed change rate exceeds the preset adaptive speed threshold and the vehicle speed change rate meets the continuity constraint condition, the corresponding time interval is identified as a candidate shift interval, and false shift events caused by sampling anomalies, local noise, or data spikes are filtered out. The shift determination step involves extracting shift feature parameters for each candidate shift interval and outputting a shift determination result based on the shift feature parameters. The test compliance determination step involves determining the representation time of the shift event based on the shift determination result, extracting the vehicle speed value corresponding to that time, comparing it with the preset shift timing determination rule, and outputting the test compliance determination result. The test report generation step generates a test report based on the shift determination result and the test compliance determination result.

2. The vehicle shifting test method based on on-board diagnostic interface timing data according to claim 1, characterized in that: In the data processing step, the preprocessing of the measured time series data includes: time synchronization, outlier removal, and smoothing filtering of the measured time series data, and calculating the engine speed change rate and vehicle speed change rate based on adjacent sampling times. The speed ratio characterization parameter is the ratio of the engine speed signal and the vehicle speed signal. When the vehicle speed signal is lower than a preset lower vehicle speed threshold, the measured time series data at that sampling time is removed from the dataset used to establish the steady-state speed ratio interval.

3. The vehicle shifting test method based on on-board diagnostic interface timing data according to claim 1, characterized in that: In the data processing step, the preset steady-state condition is: within a continuous preset time period, the absolute values ​​of the engine speed change rate, the absolute values ​​of the vehicle speed change rate, and the fluctuation range of the speed ratio characterization parameter of the tested vehicle all do not exceed the corresponding preset threshold range. The preset threshold corresponding to the absolute value of the engine speed change rate is an adaptive speed threshold, which is dynamically adjusted during cyclic testing. The adjustment process includes: Calculate the standard deviation σn of the rate of change of engine speed in the steady-state driving segment; Calculate the speed ratio fluctuation rate σr of the speed ratio characterization parameter in the steady-state driving segment; Calculate the difference ΔC between the center values ​​of adjacent steady-state speed ratio intervals; The adaptive speed threshold θadp is adjusted based on the sampling period Δt, the standard deviation of the engine speed change rate σn, the speed ratio fluctuation rate σr, and the difference in center values ​​between adjacent intervals ΔC. The formula for calculating the adaptive speed threshold θadp is as follows: θadp = α·σn + β·σr / Δt + γ·ΔC / Tavg; Where Tavg is the average duration of historical shift samples, and α, β, and γ are weighting coefficients, which are obtained by correcting historical test samples, manually reviewed samples, or by preset according to vehicle type, transmission type, and test item type.

4. The vehicle shifting test method based on on-board diagnostic interface timing data according to claim 1, characterized in that: In the shift determination step, the shift characteristic parameters include the steady-state speed ratio range before shift, the steady-state speed ratio range after shift, the shift duration, the amplitude of engine speed change, the peak value of engine speed change rate, the vehicle speed change rate, and the deviation of the speed ratio characterization parameters from the steady-state speed ratio range.

5. The vehicle shifting test method based on on-board diagnostic interface timing data according to claim 1, characterized in that: In the shift determination step, the shift determination result includes a shift event and the corresponding determination confidence level. After obtaining the determination confidence level of the shift event, a review is performed, including: When the confidence level of the judgment is higher than the preset high confidence threshold, the corresponding gear shifting event will be included in the test compliance judgment. When the confidence level of the judgment is lower than the preset low confidence threshold, a verification mark is generated, and the occurrence time of the corresponding shift event, the boundary of the candidate shift interval, and the shift feature parameters are marked in the test report. When the confidence level is within the preset confidence threshold range, the corresponding shift event is marked as an intermediate confidence level event, and automatic judgment or manual review is selected according to the test item requirements.

6. The vehicle shifting test method based on on-board diagnostic interface timing data according to claim 1, characterized in that: In the compliance assessment step, the preset shift timing determination rule includes the target shift speed range. After a gear shift event is detected, the time of the gear shift event is determined, and the vehicle speed value corresponding to the time of the gear shift event is extracted. If the vehicle speed value falls within the target gear shift speed range, a compliant gear shift result is output. If the vehicle speed is lower than the lower limit of the target shift speed range or higher than the upper limit of the target shift speed range, the result of the illegal shift will be output, and the shift event number, the time of occurrence, the corresponding vehicle speed, the target range, and the direction of the deviation will be recorded in the test report.

7. The vehicle shifting test method based on on-board diagnostic interface timing data according to claim 1, characterized in that: in, The continuity constraints include: the difference in the rate of change of vehicle speed between adjacent sampling points does not exceed the corresponding preset threshold; there are no isolated spikes within the candidate shift interval; and the number of times the sign of the rate of change of vehicle speed changes within the candidate shift interval does not exceed a preset number. When the speed ratio characterization parameter undergoes a steady-state speed ratio range shift, but the vehicle speed change rate does not meet the continuity constraint condition, the corresponding range is identified as a pseudo-shift event and eliminated.

8. A vehicle shift testing system based on on-board diagnostic interface timing data, used to perform the vehicle shift testing method based on on-board diagnostic interface timing data as described in any one of claims 1-7, characterized in that, include: The signal acquisition module is used to acquire the measured timing data of the vehicle under test during cyclic testing, at least through the vehicle diagnostic interface of the vehicle under test. The data processing module is used to preprocess the measured time series data, calculate the engine speed change rate, vehicle speed change rate and speed ratio characterization parameter used to characterize the power transmission state based on the preprocessed engine speed signal and vehicle speed signal, and identify steady-state driving segments that meet preset steady-state conditions from the preprocessed data. The steady-state speed ratio range establishment module is used to analyze the speed ratio characterization parameters of the steady-state driving segment and establish multiple steady-state speed ratio ranges. The candidate shift interval identification module is used to search for the migration process of the speed ratio characterization parameter between different steady-state speed ratio intervals from the preprocessed measured time series data. During the migration process, when the engine speed change rate exceeds the preset adaptive speed threshold and the vehicle speed change rate meets the continuity constraint condition, the corresponding time interval is identified as a candidate shift interval, and false shift events caused by sampling abnormalities, local noise or data spikes are filtered out. The shift determination module is used to extract shift feature parameters for each of the candidate shift intervals and output a shift determination result based on the shift feature parameters. The test compliance determination module is used to determine the representation time of the shift event based on the shift determination result, extract the vehicle speed value corresponding to that time, compare it with the preset shift timing determination rule, and output the test compliance determination result. The test report generation module generates a test report based on the shift determination result and the test compliance determination result.

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