A method for compiling a powertrain reliability test operating condition map

Abstract

The present application discloses a method for compiling a powertrain reliability test operating condition map, which relates to the technical field of powertrain reliability testing. The method comprises extracting execution actions from CAN bus data of multiple vehicles in a short period of time, classifying ordinary accelerator actions and braking actions, converting them proportionally to obtain all execution actions in a long period of time, and performing Weibull distribution statistics on them respectively to obtain the optimal number of times each type of execution action can cover 75% of vehicles. At least one execution action is configured within different vehicle speed variation ranges to obtain multiple groups of final action combinations, and the number of execution actions in all final action combinations meets the optimal number. Multiple final action combinations are integrated to obtain driving curves, and multiple driving curves are integrated to obtain a powertrain reliability test operating condition map. The present application can obtain an operating condition map that can accurately simulate the user's driving behavior habits based on short-term driving data, which helps to improve the discovery of powertrain software problems and user experience problems.

Description

Technical Field

[0001] The present application relates to the technical field of powertrain reliability testing, and in particular to a method for compiling a powertrain reliability test operating condition map. Background Art

[0002] To verify the reliability of an automotive powertrain and ensure it is free of problems such as piston ring breakage, connecting rod deformation, cylinder scuffing, oil and water leaks, the powertrain undergoes bench-level or vehicle-level reliability testing. Reliability testing involves operating the powertrain on a test bench or on a real road according to a specific operating profile. The basis for creating the operating profile is to translate user behavior to the test bench or on a standard road, and this translation is crucial.

[0003] The existing technology uses fatigue damage calculation methods to convert the user's total damage equivalently to the test bench or actual road. The specific implementation steps are: (1) Investigate the driving trajectory, speed, signal, CAN signal torque and other data information of a certain number of users; (2) Calculate the total damage of each user based on the torque data; (3) Draw a Weibull distribution diagram (Weibull distribution diagram) containing the total damage of all users and determine the target total damage of a certain proportion of users; (4) Set a certain cyclic working condition on the test bench or actual road, and its total damage is consistent with the target total damage obtained through the Weibull distribution.

[0004] The technical solution of the existing technology is to connect the engine to the gearbox and place it on the test bench, and connect the output end of the gearbox to the dynamometer. The load can be applied according to the working conditions, and the corresponding gearbox gear is changed according to the shifting timing. The engine intake, oil supply, exhaust, cooling, and lubrication systems are all connected to the corresponding supporting equipment to ensure the normal operation of the engine. (1) The engine speed is set to 750rad / min-4000rad / min and the full working condition cycle is scanned for 100 hours; (2) The engine is set to run continuously for 100 hours at the highest load and highest speed; (3) The speed and gear setting of the whole vehicle are simulated to accelerate from 0km / h full throttle to the highest speed, and the cycle is repeated for 100 hours. The cumulative total damage calculated under the above three working conditions is consistent with the target total damage obtained through Weibull distribution.

[0005] The technical solution of the existing technology has the following disadvantages: (1) It is far from the actual driving behavior of the user and cannot cover the user's working conditions. (2) This test method is difficult to verify software-related issues. (3) The test efficiency coefficient of this test method is relatively large, which can better verify the strength performance and other basic functions of the mechanical structure throughout the life cycle of the powertrain, but it is difficult to verify user experience issues.

[0006] The technical solution of the second existing technology is to drive the actual vehicle for about 60,000 km, which mainly includes three operating conditions: (1) high-speed uniform speed operating condition, with a uniform speed between 130km / h and 160km / h for more than 90% of the time; (2) variable operating condition, repeatedly accelerating from 0km / h to 130km / h and back and forth; (3) accelerating from 0km / h to 60km / h, maintaining a uniform speed of 60km / h for a certain distance, accelerating from 60km / h to 120km / h, and repeating the above process. The cumulative total damage calculated under the above three operating conditions is consistent with the target total damage obtained by Weibull distribution.

[0007] The technical solution of the second existing technology has the following disadvantages: (1) Most users travel on urban roads, where traffic jams frequently occur. Simulating traffic jams in the test will significantly extend the test period. The existing damage calculation method uses other working conditions to replace such time-consuming working conditions, which makes it impossible to simulate users in practice, making it difficult to verify some user experience issues. (2) The theoretical test efficiency coefficient of the whole vehicle test on the actual road is relatively low, making it difficult to verify the strength performance and other basic functions of the mechanical structure throughout the life cycle of the powertrain. Summary of the Invention

[0008] In response to the defects in the existing technology, the purpose of this application is to provide a method for compiling a powertrain reliability test operating condition map, which can obtain an operating condition map that can accurately simulate the user's driving behavior habits based on short-term driving data, and help improve the discovery of powertrain software problems and user experience problems.

[0009] In order to achieve the above objectives, the technical solutions adopted are:

[0010] The first aspect of the present application provides a method for compiling a powertrain reliability test operating condition map, comprising:

[0011] Acquire CAN bus data of a plurality of vehicles when they travel for a preset first time period;

[0012] Extracting all execution actions based on the CAN bus data, the execution actions include normal accelerator pedaling actions, fluctuating accelerator pedaling actions, step accelerator pedaling actions, braking actions, and free sliding actions, classifying normal accelerator pedaling actions according to maximum throttle opening, and classifying braking actions according to maximum braking rate;

[0013] The execution times of all the execution actions of the preset second duration are converted proportionally according to the execution times of all the execution actions, and the preset first duration is less than the preset second duration;

[0014] Perform Weibull distribution statistics on all execution actions of the preset second duration to obtain the optimal number of execution actions for each type to cover 75% of vehicles;

[0015] A plurality of preliminary action combinations corresponding to different vehicle speed ranges are obtained by combining ordinary accelerator pedaling actions, braking actions, or free sliding actions respectively; a uniform speed action is inserted into the preliminary action combinations to obtain a final action combination, wherein the uniform speed action includes a fluctuating accelerator pedaling action and a step-by-step accelerator pedaling action; and the sum of the executed actions in all the final action combinations meets the optimal number of times;

[0016] The final action combination of at least one vehicle speed variation range is integrated to obtain a driving curve, and multiple driving curves are integrated to obtain a powertrain reliability test condition map.

[0017] In some embodiments, the CAN bus data includes an accelerator pedal opening signal, a vehicle speed signal, a brake signal, a vehicle acceleration signal, and a cruise control status signal;

[0018] The sampling frequency of the CAN bus data is not less than 10 Hz;

[0019] When the frequency of the CAN bus data is greater than 20 Hz, it is first down-converted to between 10 Hz and 20 Hz and then sampled.

[0020] In some embodiments, the method further comprises:

[0021] Decode the CAN bus data to obtain the accelerator pedal opening data A a , vehicle speed data V v , Braking data B b , vehicle acceleration data and cruise control status data C c , a is a positive integer, v is a positive integer, b is a positive integer, and c is a positive integer;

[0022] All normal accelerator pedaling actions, fluctuating accelerator pedaling actions, and step accelerator pedaling actions are extracted based on the accelerator pedal opening data and vehicle speed data. All braking actions are extracted based on the braking data and vehicle acceleration data. All free sliding actions are extracted based on the accelerator pedal opening data, vehicle speed data, braking data, and cruise control status data.

[0023] In some embodiments, extracting all common accelerator pedal actions based on the accelerator pedal opening data and the vehicle speed data specifically includes the following steps:

[0024] From the first accelerator pedal opening data A whose accelerator pedal opening is greater than 0 x First, determine whether A exists x+1 -A x ≥0 or Ax -A x+3 <8%, if so, continue to make the judgment until A x+n+1 -A x+n <0, A x+n -A x+n+3 ≥8% and V x+n -V x ≥5km / h, will be from A x Start until A x+n Counts as a normal accelerator pedal press; and

[0025] From the first accelerator pedal opening data A whose accelerator pedal opening is greater than 0 x First, determine whether A exists x+1 -A x ≥0 or A x -A x+3 <8%, if so, continue to make the judgment until A is satisfied x+n+1 =0, A x+n+2 =0 or A x+n+3 =0 and V x+n -V x ≥5km / h, will be from A x Start until A x+n It is counted as a normal accelerator pedal action;

[0026] The maximum value of each normal accelerator pedaling action is recorded as the maximum throttle opening of this action.

[0027] In some embodiments, extracting all fluctuating accelerator pedal actions based on the accelerator pedal opening data and the vehicle speed data specifically includes the following steps:

[0028] From the first accelerator pedal opening data A whose accelerator pedal opening is greater than 0 x First, determine whether A exists x+1 -A x ≥0 or A x -A x+3 <8%, if so, continue to make the judgment until A x+n+1 -A x+n <0, A x+n -A x+n+3 ≥8% and V x+n -V x <5km / h, will go from A x Start until A x+n It is counted as one throttle-pressing action.

[0029] In some embodiments, extracting all step-by-step accelerator pedal actions based on the accelerator pedal opening data and the vehicle speed data specifically includes the following steps:

[0030] From the first accelerator pedal opening data A whose accelerator pedal opening is greater than 0 x First, determine whether A exists x+1 -A x ≥0 or A x -A x+3 <8%, if so, continue to make the judgment until A is satisfied x+n+1 =0, A x+n+2 =0 or A x+n+3 =0 and V x+n -V x <5km / h, will go from A x Start until A x+n This is counted as one throttle step.

[0031] In some embodiments, the classification of ordinary accelerator pedaling actions according to the maximum accelerator opening and the classification of braking actions according to the maximum braking rate specifically include the following steps:

[0032] The accelerator pedal opening data corresponding to all common accelerator pedal pressing actions are counted according to the 1 / 8, 2 / 8, 4 / 8, and 8 / 8 throttle opening classifications, and the number of common accelerator pedal pressing actions performed according to the 1 / 8, 2 / 8, 4 / 8, and 8 / 8 throttle opening classifications is obtained;

[0033] The 1 / 8 throttle opening is used to indicate that 0 < maximum throttle opening ≤ 15%;

[0034] The 2 / 8 throttle opening is used to indicate that 15% < maximum throttle opening ≤ 30%;

[0035] The 4 / 8 throttle opening is used to indicate that 30% < maximum throttle opening ≤ 65%;

[0036] The throttle opening of 8 / 8 is used to represent 65%<maximum throttle opening≤100%.

[0037] In some embodiments, classifying the braking actions according to the maximum braking rate specifically includes the following steps:

[0038] Collect statistics on the vehicle acceleration data corresponding to all braking actions, define data less than zero as deceleration, convert the deceleration into gravity acceleration g as the unit, and convert the deceleration into a positive value through absolute value processing;

[0039] Braking actions with a maximum deceleration of ≥0.5g are classified as emergency braking;

[0040] Braking actions with a maximum deceleration of 0.5g or greater or greater than 0.25g are classified as 0.3g braking;

[0041] Braking actions with a maximum deceleration of 0.25 ≥ ≥ 0.15 g are classified as 0.2 g braking;

[0042] Braking actions with a maximum deceleration of less than 0.15g are classified as 0.1g braking.

[0043] In some embodiments, extracting all free sliding actions based on the accelerator pedal opening data, vehicle speed data, braking data, and cruise control state data specifically includes the following steps:

[0044] From the first accelerator pedal opening data A where the accelerator pedal opening is equal to 0 and the brake data is equal to 0 x and brake data B x First, determine whether A exists x-1 >0 or B x-1 > any one of 0 and from A x+1 to A x+n are equal to 0, from B x+1 to B x+n are equal to 0, V x ≥30km / h, cruise control data C x+1 to C x+n are equal to 0 and n≥30, the V x Start until V x+n This is counted as one free sliding action.

[0045] In some embodiments, inserting a uniform speed movement into the preliminary movement combination to obtain a final movement combination specifically includes the following steps:

[0046] For each initial action combination corresponding to the vehicle speed range, all types of common accelerator pedaling actions are classified as acceleration actions, and all types of braking actions and free sliding actions are classified as deceleration actions;

[0047] When it is determined that the vehicle speed after the acceleration action is completed or the vehicle speed after the deceleration action is completed reaches the preset through-vehicle speed, a uniform-speed action of the corresponding uniform-speed total mileage corresponding to the through-vehicle speed is inserted after the completion of the action to obtain the final action combination; when the through-vehicle speed is 60km / h, 80km / h, and 100km / h, the uniform-speed action includes a fluctuating accelerator action and a step-by-step accelerator action.

[0048] The beneficial effects of the technical solution provided by this application include:

[0049] The system can extract various user driving actions from short-term driving data, amplify them to obtain various long-term driving actions, and apply Weibull distribution statistics to these actions to determine the optimal number of times each action type can be executed across a large number of vehicles. By combining various actions at different vehicle speeds and inserting uniform-speed actions, the system can obtain a final action combination that accurately simulates user driving behavior habits. The final action combinations for at least one speed range are then integrated to form a driving curve. Multiple driving curves are then integrated to form a powertrain reliability test operating condition map, resulting in an operating condition map that accurately simulates user driving behavior habits, helping to improve the detection of powertrain software issues and user experience issues. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 The figure is a flow chart of a method for compiling a powertrain reliability test operating condition map in an embodiment of the present invention.

[0051] Figure 2 This is a flowchart of extracting all execution actions based on CAN bus data in step S2.

[0052] Figure 3 This is a flow chart of inserting a uniform speed action into a preliminary action combination to obtain a final action combination in step S4.

[0053] Figure 4 Schematic diagram of the road in the test field in the embodiment of the present invention.

[0054] Figure 5 Schematic diagram of the final action combination in an embodiment of the present invention. DETAILED DESCRIPTION

[0055] The present application is further described in detail below with reference to the accompanying drawings and embodiments.

[0056] The powertrain reliability test refers to the test in which the transmission mechanism of a car's powertrain is subjected to vibration and impact after a long period of driving, and fatigue fracture may occur after a certain movement cycle; its gears, lubricants, chains and other mechanisms are subjected to friction damage and may wear out after a certain driving cycle. To verify the above problems, the vehicle is driven on actual roads or on a test bench at a certain speed and load for a certain period to confirm whether its powertrain will have reliability problems.

[0057] The operating condition map refers to the operating condition requirements of the powertrain or vehicle's operating speed, acceleration, and load during vehicle road tests or bench tests.

[0058] The test efficiency coefficient means that driving for one hour on the standard road of the test site or on the test bench is equivalent to the user driving for n hours on the actual road. n is the test efficiency coefficient. The larger the n value is, the longer the driving time of the verified user under the premise of the same test cycle.

[0059] like Figure 1 As shown, an embodiment of the present invention provides a method for compiling a powertrain reliability test condition map, which includes extracting execution actions from CAN bus data of multiple vehicles in a short period of time, classifying ordinary accelerator actions and braking actions, converting them proportionally to obtain all execution actions in a long period of time, and performing Weibull distribution statistics on them respectively to obtain the optimal number of times that each type of execution action can cover 75% of vehicles. At least one execution action is configured within different vehicle speed variation ranges to obtain multiple groups of final action combinations, and the number of execution actions in all final action combinations meets the optimal number. Multiple final action combinations are integrated to obtain driving curves, and multiple driving curves are integrated to obtain a powertrain reliability test condition map. The present application can obtain a condition map that can accurately simulate the user's driving behavior habits based on short-term driving data, and can ensure that the test condition map is closer to the user's actual driving condition, which helps to improve the discovery effect of powertrain software problems and user experience problems.

[0060] Specifically, such as Figure 1 As shown, the above method includes:

[0061] Acquire CAN bus data of a plurality of vehicles when they travel for a preset first time period;

[0062] Step S1: extract all execution actions based on the above-mentioned CAN bus data, wherein the above-mentioned execution actions include normal accelerator pedaling action, fluctuating accelerator pedaling action, step accelerator pedaling action, braking action, and free sliding action. Normal accelerator pedaling action is classified according to the maximum throttle opening, and braking action is classified according to the maximum braking rate.

[0063] Step S2: proportionally convert the execution times of all the execution actions to obtain the execution times of the preset second duration, wherein the preset first duration is less than the preset second duration.

[0064] Step S3: Perform Weibull distribution statistics on all execution actions of the preset second time period to obtain the optimal number of times for each type of execution action to cover 75% of vehicles.

[0065] Step S4: Combine the normal accelerator pedaling action, the braking action, or the free-sliding action to obtain multiple preliminary action combinations corresponding to different vehicle speed ranges. A uniform speed action is inserted into the preliminary action combinations to obtain a final action combination. The uniform speed action includes a fluctuating accelerator pedaling action and a stepped accelerator pedaling action. The total number of actions executed in all the final action combinations meets the optimal number.

[0066] Step S5: Integrate the final action combination of at least one vehicle speed variation range to obtain a driving curve, and integrate multiple driving curves to obtain a powertrain reliability test operating condition map.

[0067] In this embodiment, various user driving actions can be extracted from short-term driving data, amplified to obtain various long-term driving actions. Weibull distribution statistics are then applied to these actions to determine the optimal number of times each action type can be executed across a majority of vehicles. By combining various actions at different vehicle speeds and inserting uniform-speed actions, a final action combination that accurately simulates the user's driving behavior is obtained. These final action combinations across at least one speed range are then integrated to form a driving curve. Multiple driving curves are then integrated to form a powertrain reliability test operating condition map. This results in an operating condition map that accurately simulates the user's driving behavior, helping to improve the detection of powertrain software and user experience issues.

[0068] In a preferred embodiment, the CAN bus data includes an accelerator pedal opening signal, a vehicle speed signal, a brake signal, a vehicle acceleration signal, and a cruise control status signal.

[0069] The sampling frequency of the above CAN bus data is not less than 10 Hz.

[0070] In this embodiment, market research is conducted to collect CAN bus data from 50 or more users driving their vehicles for two months. This data includes, but is not limited to, mileage, vehicle speed, accelerator pedal position, brake signals, vehicle acceleration, and cruise control status signals. The sampling frequency of the CAN bus data is no less than 10 Hz. Using two months of CAN bus data as short-term data, a proportional conversion can be used to extrapolate to a longer-term performance period, such as six years, thereby improving the theoretical test efficiency coefficient.

[0071] In a preferred embodiment, if Figure 2 As shown, the above step S2 extracts all execution actions according to the CAN bus data, which may specifically include the following steps:

[0072] Step S21a: Decode the CAN bus data to obtain the accelerator pedal opening data A a , vehicle speed data V v , Braking data B b , vehicle acceleration data and cruise control status data C c , a is a positive integer, v is a positive integer, b is a positive integer, and c is a positive integer.

[0073] Step S22a: extract all normal accelerator pedaling actions, fluctuating accelerator pedaling actions, and step accelerator pedaling actions based on the accelerator pedal opening data and vehicle speed data; extract all braking actions based on the braking data and vehicle acceleration data; and extract all free sliding actions based on the accelerator pedal opening data, vehicle speed data, braking data, and cruise control status data.

[0074] In this embodiment, the CAN bus data of each user is decoded and converted into a calculable data format, that is, the accelerator pedal opening data A is obtained. a , vehicle speed data V v , Braking data B b , vehicle acceleration data and cruise control status data C c .

[0075] In a preferred embodiment, the above step S22a extracts all common accelerator pedaling actions based on the accelerator pedal opening data and the vehicle speed data, and specifically includes the following steps:

[0076] From the first accelerator pedal opening data A whose accelerator pedal opening is greater than 0 x First, determine whether A exists x+1 -A x ≥0 or A x -A x+3 <8%, if so, continue the above judgment until A x+n+1 -A x+n <0, A x+n -A x+n+3 ≥8% and V x+n -V x ≥5km / h, will be from A x Start until A x+n Counts as a normal accelerator pedal press.

[0077] From the first accelerator pedal opening data A whose accelerator pedal opening is greater than 0 x First, determine whether A exists x+1 -A x ≥0 or A x -A x+3 <8%, if so, continue the above judgment until A is satisfied x+n+1 =0, A x+n+2 =0 or A x+n+3 =0 and V x+n -V x ≥5km / h, will be from A x Start until A x+n It is counted as a normal accelerator pedal action;

[0078] The maximum value of each normal accelerator pedaling action is recorded as the maximum throttle opening of this action.

[0079] In this embodiment, from the first data A where the accelerator pedal opening A is greater than 0, x Start calculating, A x The first data A downward x+1 , the nth data A below x+n .

[0080] A x+1 -A x ≥0, or A x -A x+3 <8%, then continue to calculate this step until A x+n+1 -A x+n <0, and A x+n -A x+n+3 ≥8%, and V x+n -V x ≥5km / h, then from A x Start to A x+n So far, it is counted as a normal accelerator pedal action.

[0081] A x+1 -A x ≥0, or A x -A x+3 <8%, then continue to calculate this step until A x+n+1 -A x+n <0, and any of the following conditions A is met x+n+1 =0, A x+n+2 =0, A x+n+3 =0, and V x+n -V x ≥5km / h, then from A x Start to A x+n So far, it is counted as a normal accelerator pedal action.

[0082] The maximum value of the accelerator pedal is equal to A x Start to A x+n The maximum value so far is defined as the throttle of this normal accelerator action.

[0083] From A x+n Start repeating the above calculation steps to obtain all common accelerator pedaling actions.

[0084] During the process of pressing the accelerator and brake, the pedal opening Ax increases first and then decreases. x+1 -A x ≥0, or A x -A x+3<8% is to judge whether the current data has a peak, that is, to judge whether it is an increasing trend or not a decreasing trend. If it meets the requirements, it is defined as a step on the accelerator. x -A x+3 <8% indicates a relatively small fluctuation value, which still belongs to the current accelerator application.

[0085] 10Hz means 10 data points per second, so the interval between two data points is 0.1s. Human reaction time is greater than 0.1s. If x+1 is too close, the interval will be too close, resulting in the two values of x and x+1 being very close. If x+5 is 0.5s later, the time interval is too long, resulting in a large difference from x. Therefore, the interval from x to x+3 is chosen to best simulate the user's real actions.

[0086] If the speed of pressing and releasing the accelerator is very fast and the increase in vehicle speed is very small, it is judged that it is not an ordinary accelerator pressing action. Furthermore, if the accelerator opening fluctuates in a small range, it is a fluctuating accelerator pressing action. If the accelerator opening opens and closes quickly, it is a step accelerator pressing action.

[0087] In a preferred embodiment, the above step S22a extracts all fluctuating accelerator pedaling actions based on the accelerator pedal opening data and the vehicle speed data, and specifically includes the following steps:

[0088] From the first accelerator pedal opening data A whose accelerator pedal opening is greater than 0 x First, determine whether A exists x+1 -A x ≥0 or A x -A x+3 <8%, if so, continue the above judgment until A x+n+1 -A x+n <0, A x+n -A x+n+3 ≥8% and V x+n -V x <5km / h, will go from A x Start until A x+n It is counted as one throttle-pressing action.

[0089] In this embodiment, A x+1 -A x ≥0, or A x -A x+3 <8%, then continue to calculate this step until A x+n+1 -A x+n <0, and A x+n -A x+n+3 ≥8%, and V x+n -V x <5km / h, then from Ax Start to A x+n So far, it is recorded as one wave accelerator pedal action.

[0090] From A x+n Start repeating the above calculation steps to obtain all the fluctuating accelerator pedaling actions.

[0091] In a preferred embodiment, the above step S22a extracts all the step accelerator pedal actions based on the accelerator pedal opening data and the vehicle speed data, and specifically includes the following steps:

[0092] From the first accelerator pedal opening data A whose accelerator pedal opening is greater than 0 x First, determine whether A exists x+1 -A x ≥0 or A x -A x+3 <8%, if so, continue the above judgment until A is satisfied x+n+1 =0, A x+n+2 =0 or A x+n+3 =0 and V x+n -V x <5km / h, will go from A x Start until A x+n It is counted as one step accelerator pedal action.

[0093] In this embodiment, A x+1 -A x ≥0, or A x -A x+3 <8%, then continue to calculate this step until A x+n+1 -A x+n <0, and any of the following conditions A is met x+n+1 =0, A x+n+2 =0, A x+n+3 =0, and V x+n -V x <5km / h, then from A x Start to A x+n So far it is recorded as one step accelerator pedal action.

[0094] From A x+n Start repeating the above calculation steps to obtain all step-by-step accelerator actions.

[0095] In a preferred embodiment, the above-mentioned step S22a classifies the common accelerator pedaling actions according to the maximum accelerator opening and classifies the braking actions according to the maximum braking rate, which specifically includes the following steps:

[0096] The throttle pedal opening data corresponding to all common throttle pressing actions are counted according to the throttle opening classification of 1 / 8, 2 / 8, 4 / 8, and 8 / 8, and the number of common throttle pressing actions performed according to the throttle opening of 1 / 8, 2 / 8, 4 / 8, and 8 / 8 is obtained.

[0097] The above-mentioned 1 / 8 throttle opening is used to represent 0<maximum throttle opening ≤15%.

[0098] The above-mentioned 2 / 8 throttle opening is used to indicate that 15% < maximum throttle opening ≤ 30%.

[0099] The above-mentioned throttle opening of 4 / 8 is used to indicate that 30% is less than the maximum throttle opening and is less than or equal to 65%.

[0100] The above 8 / 8 throttle opening is used to represent 65%<maximum throttle opening≤100%.

[0101] In this embodiment, the driving data of each customer within 2 months is counted according to the throttle opening classification of 1 / 8, 2 / 8, 4 / 8, and 8 / 8, and the number of times the normal accelerator pedaling action is performed according to the throttle opening of 1 / 8, 2 / 8, 4 / 8, and 8 / 8 is obtained.

[0102] In a preferred embodiment, the classification of the braking actions according to the maximum braking rate in step S22a specifically includes the following steps:

[0103] The acceleration data of the whole vehicle corresponding to all braking actions are counted, and the data less than zero is defined as deceleration. The deceleration is converted into the unit of gravity acceleration g, and the deceleration is converted into a positive value through absolute value processing.

[0104] Braking actions with a maximum deceleration ≥ 0.5g are classified as emergency braking.

[0105] Braking actions with a maximum deceleration of 0.5g or greater and a maximum deceleration of 0.25g or greater are classified as 0.3g braking.

[0106] Braking actions with a maximum deceleration of 0.25 g or greater and a maximum deceleration of 0.15 g or greater are classified as 0.2 g braking.

[0107] Braking actions with a maximum deceleration of less than 0.15g are classified as 0.1g braking.

[0108] In this embodiment, the data of the vehicle acceleration signal less than 0 is extracted and defined as deceleration, which is converted into gravity acceleration g (10m 2 / s) as the unit, convert all deceleration values to positive values. When the brake switch signal is 1, it is considered that the user has braked, and when it is 0, the user has not braked. One braking action is counted from the moment the first brake switch signal is 1 to the moment the next brake switch signal is 0. Repeat the previous calculation for subsequent data.

[0109] When a car decelerates, it is generally less than 1g, unless it crashes. Normal deceleration is between 0.1g-0.3g.

[0110] Any braking action with a maximum deceleration signal greater than or equal to 0.5g is considered an emergency brake. Any braking action with a maximum deceleration signal greater than or equal to 0.25g and less than 0.5g is considered a 0.3g brake. Any braking action with a maximum deceleration signal greater than or equal to 0.15g and less than 0.25g is considered a 0.2g brake. Any braking action with a maximum deceleration signal less than 0.15g is considered a 0.1g brake. The total number of each type of braking action is counted separately: emergency brake, 0.3g, 0.2g, and 0.1g.

[0111] In a preferred embodiment, the above step S22a extracts all free sliding actions based on the accelerator pedal opening data, vehicle speed data, braking data, and cruise control state data, and specifically includes the following steps:

[0112] From the first accelerator pedal opening data A where the accelerator pedal opening is equal to 0 and the brake data is equal to 0 x and brake data B x First, determine whether A exists x-1 >0 or B x-1 > any one of 0 and from A x+1 to A x+n are equal to 0, from B x+1 to B x+n are equal to 0, V x ≥30km / h, cruise control data C x+1 to C x+n are equal to 0 and n≥30, the V x Start until V x+n This is counted as one free sliding action.

[0113] In this embodiment, from the first data A where the accelerator pedal opening A is equal to 0 and the brake signal B is equal to 0, x 、B x Start calculating, A x The first data A downward x+1 , the nth data A below x+n .

[0114] A x-1 >0 or B x-1 >0, and from A x+1 to A x+n are equal to 0, and from B x+1 to B x+n are equal to 0, and V x≥30km / h, and cruise control C x+1 to C x+n are all equal to 0, and n≥30, then from V x Start to V x+n This is counted as one free sliding action.

[0115] Count the total number of free skating actions.

[0116] In a preferred embodiment, the mileage data of each user for two months is summarized and statistically analyzed, including the total number of each common accelerator action of 1 / 8, 2 / 8, 4 / 8, 8 / 8, the total number of each braking action of emergency braking, 0.3g, 0.2g, 0.1g, the total number of free sliding actions, the total number of step accelerator actions, and the total number of fluctuating accelerator actions.

[0117] According to the mileage in the user data collected for 2 months, the mileage of the user's car use for 6 years is proportionally deduced, and then the total number of each normal accelerator action of 1 / 8, 2 / 8, 4 / 8, 8 / 8, the total number of each braking action of emergency braking, 0.3g, 0.2g, 0.1g, the total number of free sliding actions, the total number of step accelerator actions, and the total number of fluctuating accelerator actions contained in the mileage data of each user for 6 years are obtained.

[0118] Perform Weibull distribution statistics on the total number of each common accelerator pedaling action of 1 / 8, 2 / 8, 4 / 8, and 8 / 8, as well as the total number of each braking action of emergency braking, 0.3g, 0.2g, and 0.1g, obtained in the previous step, to obtain the number of times each throttle opening and each braking action can cover 75% of users.

[0119] In this embodiment, each time you refuel, for example, step on the full throttle, it is possible to accelerate from 0 to 60 or from 0 to 100, but the acceleration from 0 to 10 is very rare and almost negligible. As mentioned above, for example, there are 50 users, and the number of full throttle times is different for each user. Based on these times, a Weibull distribution function curve for the number of full throttle times can be derived. After this curve is derived, a value covering 75% can be determined, thereby obtaining a working condition map that can accurately simulate the user's driving behavior habits, which helps to improve the discovery of powertrain software problems and user experience problems.

[0120] In actual tests, after a certain test vehicle has completed the above-mentioned operating condition map with a total test mileage of approximately 48,000 km, consisting of 23 driving curves, and each driving curve needs to be executed hundreds to thousands of times, it can effectively discover possible software problems in the vehicle and problems that cause poor user experience.

[0121] Table 1 below shows the optimal number of times each type of execution action can cover 75% of vehicles in a specific embodiment, obtained through Weibull distribution statistics, where free sliding refers to free sliding action, step throttle refers to step throttle action, and fluctuating throttle refers to fluctuating throttle action.

[0122] Driving behavior 1 / 8 throttle 2 / 8 throttle 4 / 8 throttle 8 / 8 throttle emergency braking 0.3g 0.2g 0.1g Freeride Step throttle Fluctuating throttle Total number of executions a b c d e f g h i j k

[0123] Table 1 List of the optimal number of times each type of action can cover 75% of vehicles

[0124] In a preferred embodiment, if Figure 3 As shown, the above step S4 inserts the uniform speed action into the preliminary action combination to obtain the final action combination, which specifically includes the following steps:

[0125] Step S41a: for each preliminary action combination corresponding to the vehicle speed variation range, classify all types of common accelerator pedaling actions as acceleration actions, and classify all types of braking actions and free sliding actions as deceleration actions.

[0126] Step S42a: When it is determined that the vehicle speed after the acceleration action or the deceleration action reaches a preset through-speed, a uniform-speed action corresponding to the uniform-speed total mileage at the through-speed is inserted after the completion of the action to obtain a final action combination. When the through-speed is 60 km / h, 80 km / h, and 100 km / h, the uniform-speed action includes a fluctuating accelerator pedaling action and a stepped accelerator pedaling action.

[0127] In this embodiment, varying vehicle speeds are combined with various conventional accelerator pedaling, braking, and free-sliding actions, each performed at the times shown in Table 2 below. These actions are categorized into two main categories: acceleration and deceleration (including braking, deceleration, and free-sliding). For example, if a 1 / 8 throttle opening is used to accelerate a vehicle from 10 km / h to 20 km / h, this driving action is performed a4 times in total. The sum of a1, a2, a3, and a4 times equals the a times shown in Table 1 above.

[0128]

[0129] Table 2 Preliminary action combination list

[0130] like Figure 5 Figure 2 shows another example of a final action combination, where the x-axis represents mileage and the y-axis represents driving speed. This final action combination includes a 1 / 8 throttle action a1, a constant speed action u1, a 2 / 8 throttle action b1, a 0.1g braking action h1, an 8 / 8 throttle action d1, a 0.2g braking action g1, a constant speed action u2, a 4 / 8 throttle action c1, a free sliding action i1, a fluctuating throttle action t1, and an emergency braking action e1.

[0131] Furthermore, uniform-speed actions are interspersed between the aforementioned acceleration and deceleration combinations, ensuring that the total mileage for each uniform-speed driving pattern is configured as follows. Uniform-speed actions can be randomly distributed between acceleration and deceleration combinations, meaning that the uniform-speed mileage can be freely distributed between acceleration and deceleration combinations. This configuration is sufficient as long as the total uniform-speed mileage for all uniform-speed actions corresponding to the same vehicle speed within a single final action combination meets the following requirements.

[0132] At a speed of 160 km / h, the total mileage at a constant speed is 2,000 km to 3,000 km. At a speed of 140 km / h, the total mileage at a constant speed is 2,000 km to 3,000 km. At a speed of 120 km / h, the total mileage at a constant speed is 2,000 km to 3,000 km. At a speed of 100 km / h, the total mileage at a constant speed is 2,000 km to 3,000 km. At a speed of 80 km / h, the total mileage at a constant speed is 1,000 km to 2,000 km. At a speed of 70 km / h, the total mileage at a constant speed is 500 km to 1,000 km. At a speed of 60 km / h, the total mileage at a constant speed is 1,000 km to 2,000 km. At a speed of 50 km / h, the total mileage at a constant speed is 500 km to 1,000 km. At a speed of 40 km / h, the total mileage at a constant speed is 500 km to 1,000 km. The total mileage of the constant speed movements of 5km / h, 10km / h, 20km / h and 30km / h is 200km-500km.

[0133] Furthermore, the above-mentioned uniform speed action can be a uniform speed action with a constant vehicle speed, or can be achieved by a step throttle action with a small and rapid fluctuation in vehicle speed, or can be achieved by a step throttle action with a large and rapid fluctuation in vehicle speed.

[0134] Specifically, the step-by-step accelerator action is performed at vehicle speeds of 60km / h, 80km / h, and 100km / h as follows:

[0135] Start from 0 accelerator pedal opening and increase it to about 20%, then completely release the accelerator pedal and wait for a certain period of time. This counts as one action. During this period, ensure that the vehicle speed does not exceed the target speed by more than ±5 km / h (60±5 km / h, 80±5 km / h, 100±5 km / h). Repeat the above steps 10 times as a loop. This loop can be repeated multiple times to ensure that the number of times the action is performed is approximately equal to j times.

[0136] Set the throttle pedal to fluctuate as follows at speeds of 60km / h, 80km / h, and 100km / h:

[0137] Start with the accelerator pedal open at approximately 20%, then gradually reduce it to approximately 8%, and then gradually increase it to approximately 20%. This counts as one action. During this time, ensure that the vehicle speed does not exceed ±8 km / h of the target speed (60 ± 8 km / h, 80 ± 8 km / h, 100 ± 8 km / h). Repeat the above steps 10 times as a loop. This loop can be repeated multiple times to ensure that the action is executed approximately k times.

[0138] Furthermore, different acceleration, deceleration, constant speed, step throttle, and fluctuating throttle actions at different vehicle speeds are combined to create a variety of driving curves. Each acceleration curve starts at 0 speed and ends at 0 speed. During this period, it can include multiple acceleration, deceleration, constant speed, step throttle, and fluctuating throttle actions. Some actions can also be repeated continuously to ensure that all actions can be safely executed on the roads of the corresponding test site. Multiple driving curves are combined to form a powertrain reliability test condition map.

[0139] In a specific embodiment, a powertrain reliability test condition map compiled by this method has a total test mileage of about 48,000 km and consists of 23 driving curves, each of which needs to be executed hundreds to thousands of times. Figure 4 The above test site is carried out on the road.

[0140] Simulate the city traffic jam driving curve, drive 5 laps in total, 1 lap is 5.3km, and the vehicle speed covers 0-60km / h.

[0141] At the entrance to the expressway, shift into D gear and accelerate to 20 km / h with a 2 / 8 throttle. Release the accelerator pedal and immediately accelerate to 40 km / h with a 2 / 8 throttle. Release the accelerator pedal and immediately accelerate to 60 km / h with a 2 / 8 throttle. Then, step on the throttle to maintain a speed of 60 ± 5 km / h through the expressway curve. After exiting the curve, lightly apply the brake (0.1g) to reduce the speed to 20 km / h. After maintaining a constant speed for 2 seconds, continue to lightly apply the brake (0.1g) until the speed drops to 0.

[0142] After stopping for 2 seconds, accelerate the vehicle to 30 km / h using the 4 / 8 throttle pedal. Lightly apply the brake (0.1g) to decelerate the vehicle to 0 km / h. Then, accelerate the vehicle to 20 km / h using the 2 / 8 throttle pedal. Repeat the "5-20" acceleration and deceleration cycle 10 times. After stopping for 2 seconds, accelerate the vehicle to 20 km / h using the 4 / 8 throttle pedal. Immediately release the pedal and apply the 4 / 8 throttle pedal to accelerate the vehicle to 40 km / h. Then, lightly apply the brake (0.1g) to decelerate the vehicle to 0 km / h. Repeat this cycle 5 times.

[0143] After completion, stop for 2 seconds, increase the speed to 30km / h at full throttle, release the accelerator briefly and immediately accelerate to 60km / h at full throttle again, lightly apply the brake (0.1g) to decelerate to 40km / h, and then continue to accelerate to 60km / h at full throttle. After entering the curve, fluctuate the throttle to keep the speed within 60±8km / h. After exiting the curve, glide to 40km / h, then lightly brake (0.1g) to slow down and stop. After stopping for 2s, accelerate to 30km / h at full throttle, maintain a constant speed for 2s and then lightly brake to slow down to stop. After stopping for 2s, accelerate to 20km / h with 2 / 8 throttle, then accelerate to 40km / h with 4 / 8 throttle, lightly brake (0.1g) to decelerate to 10km / h, then accelerate to 60km / h with 4 / 8 throttle, lightly brake to decelerate to 20km / h, then accelerate to 60km / h with 4 / 8 throttle, then decelerate to 20km / h, then accelerate to 60km / h with 4 / 8 throttle. Then lightly apply the brake (0.1g) to decelerate to 0, stop for 2 seconds, then accelerate to 20km / h with 4 / 8 throttle, release the throttle and immediately accelerate to 40km / h with 4 / 8 throttle, release the throttle and immediately accelerate to 60km / h with 4 / 8 throttle, drive at a constant speed for 3 seconds and then decelerate freely to the exit.

[0144] After a certain test vehicle has completed the above-mentioned operating condition map with a total test mileage of approximately 48,000 km, consisting of 23 driving curves, and each driving curve needs to be executed hundreds to thousands of times, it can effectively discover possible software problems in the vehicle and problems that cause poor user experience.

[0145] The present application is not limited to the above-mentioned embodiments. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications are also considered to be within the scope of protection of the present application.

Claims

1. A method for compiling a powertrain reliability test operating condition map, characterized in that: include: Acquire CAN bus data of a plurality of vehicles when they travel for a preset first time period; Extracting all execution actions based on the CAN bus data, the execution actions include normal accelerator pedaling actions, fluctuating accelerator pedaling actions, step accelerator pedaling actions, braking actions, and free sliding actions, classifying normal accelerator pedaling actions according to maximum throttle opening, and classifying braking actions according to maximum braking rate; The execution times of all the execution actions of the preset second duration are converted proportionally according to the execution times of all the execution actions, and the preset first duration is less than the preset second duration; Perform Weibull distribution statistics on all execution actions of the preset second duration to obtain the optimal number of execution actions for each type to cover 75% of vehicles; A plurality of preliminary action combinations corresponding to different vehicle speed ranges are obtained by combining ordinary accelerator pedaling actions, braking actions, or free sliding actions respectively; a uniform speed action is inserted into the preliminary action combinations to obtain a final action combination, wherein the uniform speed action includes a fluctuating accelerator pedaling action and a step-by-step accelerator pedaling action; and the sum of the executed actions in all the final action combinations meets the optimal number of times; The final action combination of at least one vehicle speed variation range is integrated to obtain a driving curve, and multiple driving curves are integrated to obtain a powertrain reliability test condition map.

2. The method for compiling a powertrain reliability test operating condition map according to claim 1, wherein: The CAN bus data includes accelerator pedal opening signal, vehicle speed signal, brake signal, vehicle acceleration signal and cruise control status signal; The sampling frequency of the CAN bus data is not less than 10 Hz; When the frequency of the CAN bus data is greater than 20 Hz, it is first down-converted to between 10 Hz and 20 Hz and then sampled.

3. The method for compiling a powertrain reliability test operating condition map according to claim 1, wherein: The method further comprises: Decode the CAN bus data to obtain the accelerator pedal opening data , vehicle speed data , braking data , vehicle acceleration data and cruise control status data , is a positive integer, is a positive integer, is a positive integer, is a positive integer; All normal accelerator pedaling actions, fluctuating accelerator pedaling actions, and step accelerator pedaling actions are extracted based on the accelerator pedal opening data and vehicle speed data. All braking actions are extracted based on the braking data and vehicle acceleration data. All free sliding actions are extracted based on the accelerator pedal opening data, vehicle speed data, braking data, and cruise control status data.

4. The method for compiling a powertrain reliability test operating condition map according to claim 3, wherein: The method of extracting all common accelerator pedal actions based on the accelerator pedal opening data and the vehicle speed data specifically includes the following steps: Accelerator pedal opening data from the first accelerator pedal opening greater than 0 First, determine whether - ≥0 or - <8%, if so, continue to make the judgment until - <0, - ≥8% and - ≥5km / h, will be Start until It is counted as a normal accelerator pedal action; as well as Accelerator pedal opening data from the first accelerator pedal opening greater than 0 First, determine whether - ≥0 or - <8%, if so, continue to make the above judgment until it meets =0, =0 or =0 and - ≥5km / h, will be Start until It is counted as a normal accelerator pedal action; The maximum value of each normal accelerator pedaling action is recorded as the maximum throttle opening of this action.

5. The method for compiling a powertrain reliability test operating condition map according to claim 3, wherein: The method of extracting all fluctuating accelerator pedal actions based on the accelerator pedal opening data and the vehicle speed data specifically includes the following steps: Accelerator pedal opening data from the first accelerator pedal opening greater than 0 First, determine whether - ≥0 or - <8%, if so, continue to make the judgment until - <0, - ≥8% and - <5km / h, will Start until It is counted as one throttle-pressing action.

6. The method for compiling a powertrain reliability test operating condition map according to claim 3, wherein: The step-by-step accelerator pedaling actions are extracted based on the accelerator pedal opening data and the vehicle speed data, and specifically include the following steps: Accelerator pedal opening data from the first accelerator pedal opening greater than 0 First, determine whether - ≥0 or - <8%, if so, continue to make the above judgment until it meets =0, =0 or =0 and - <5km / h, will Start until This is counted as one throttle step.

7. The method for compiling a powertrain reliability test operating condition map according to claim 1, wherein: The classification of the common accelerator pedal pressing action according to the maximum accelerator opening specifically includes the following steps: The accelerator pedal opening data corresponding to all common accelerator pedal pressing actions are counted according to the 1 / 8, 2 / 8, 4 / 8, and 8 / 8 throttle opening classifications, and the number of common accelerator pedal pressing actions performed according to the 1 / 8, 2 / 8, 4 / 8, and 8 / 8 throttle opening classifications is obtained; The 1 / 8 throttle opening is used to indicate that 0 < maximum throttle opening ≤ 15%; The 2 / 8 throttle opening is used to indicate that 15% < maximum throttle opening ≤ 30%; The 4 / 8 throttle opening is used to indicate that 30% < maximum throttle opening ≤ 65%; The throttle opening of 8 / 8 is used to represent 65%<maximum throttle opening≤100%.

8. The method for compiling a powertrain reliability test operating condition map according to claim 1, wherein: The classification of the braking actions according to the maximum braking rate specifically includes the following steps: Collect statistics on the vehicle acceleration data corresponding to all braking actions, define data less than zero as deceleration, convert the deceleration into gravity acceleration g as the unit, and convert the deceleration into a positive value through absolute value processing; Braking actions with a maximum deceleration of ≥0.5g are classified as emergency braking; Braking actions with a maximum deceleration of 0.5g or greater than 0.25g are classified as 0.3g braking; Braking actions with a maximum deceleration of 0.25 and ≥ 0.15g are classified as 0.2g braking; Braking actions with a maximum deceleration of less than 0.15g are classified as 0.1g braking.

9. The method for compiling a powertrain reliability test operating condition map according to claim 3, wherein: The method of extracting all free sliding actions based on the accelerator pedal opening data, vehicle speed data, braking data, and cruise control state data specifically includes the following steps: From the first accelerator pedal opening equal to 0 and brake data equal to 0 and braking data First, determine whether >0 or >0 and from arrive are equal to 0, from arrive are all equal to 0, ≥30km / h, cruise control data arrive are equal to 0 and n≥30, will be Start until This is counted as one free sliding action.

10. The method for compiling a powertrain reliability test operating condition map according to claim 1, wherein: Inserting a uniform speed action into the preliminary action combination to obtain a final action combination specifically includes the following steps: For the preliminary action combinations corresponding to each vehicle speed range, all types of common accelerator pedaling actions are classified as acceleration actions, and all types of braking actions and free sliding actions are classified as deceleration actions; When it is determined that the vehicle speed after the acceleration action is completed or the vehicle speed after the deceleration action is completed reaches the preset through-vehicle speed, a uniform-speed action of the corresponding uniform-speed total mileage corresponding to the through-vehicle speed is inserted after the completion of the action to obtain the final action combination; when the through-vehicle speed is 60km / h, 80km / h, and 100km / h, the uniform-speed action includes a fluctuating accelerator action and a step-by-step accelerator action.

Images