A method for testing and evaluating braking and coasting deceleration consistency of an electric vehicle

Abstract

This invention relates to a method for testing and evaluating the consistency of braking and coasting deceleration in electric vehicles, comprising the following steps: S1: Conducting multiple sets of comparative tests on the vehicle; the tests include vehicle coasting tests and vehicle braking tests, and the test results include the vehicle's coasting time, coasting distance, braking time, and braking distance; S2: Performing differential processing on the test results of each set of comparative tests to obtain the percentage difference of the test results of each set of comparative tests; the percentage difference includes the percentage difference in coasting distance, coasting time, braking distance, and braking time; S3: Based on a preset mapping relationship between the percentage difference and the evaluation standard, performing a weighted calculation on the percentage difference of the vehicle's coasting test and vehicle braking test for each set of tests, and then conducting a comprehensive evaluation and analysis of the vehicle's deceleration consistency. This invention can measure and evaluate the consistency of vehicle braking deceleration and coasting deceleration.

Description

Technical Field

[0001] This invention relates to the field of automotive testing technology, and specifically to a method for evaluating the consistency of braking and coasting deceleration in electric vehicles. Background Technology

[0002] Electric vehicles have energy recovery systems, which significantly impact their deceleration performance. These systems convert the kinetic energy generated during coasting and braking into electrical energy, improving energy efficiency and increasing driving range. However, during energy recovery, a noticeable dragging sensation occurs as the vehicle decelerates additionally, affecting braking and coasting distances. This can lead to driver misjudgment and accidents.

[0003] During the operation of an energy recovery system, the consistency of deceleration during coasting or braking with that during energy recovery is crucial to braking performance, as it directly relates to braking safety and efficiency. Good deceleration consistency ensures stability and predictability during braking, allowing the driver to accurately control vehicle deceleration and effectively avoid accidents caused by improper braking in emergency situations. Consistent deceleration performance helps reduce braking distance, which is essential for avoiding collisions or mitigating their consequences during emergency braking.

[0004] In the prior art, such as the invention patent with authorization publication number CN118810451A, "A Coordinated Control System and Method for Energy Recovery of Electric Vehicles with Drive-by-Wire", it coordinates and controls multiple active safety functions to optimize braking response, aiming to reduce the discomfort of drivers and passengers during energy recovery. However, it does not test or evaluate the deceleration differences caused by the operation of the energy recovery system. Summary of the Invention

[0005] The purpose of this invention is to provide a method for testing and evaluating the consistency of braking and coasting deceleration in electric vehicles, so as to solve the problem of deceleration differences caused by the operation of energy recovery systems in the prior art.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for evaluating the consistency of braking and coasting deceleration in electric vehicles includes the following steps:

[0008] S1: Conduct multiple sets of comparative tests on the vehicle; the tests include vehicle coasting tests and vehicle braking tests, and the test results include the vehicle's coasting time, coasting distance, braking time and braking distance;

[0009] S2: Perform differential processing on the test results of each group of comparative tests to obtain the percentage difference of the test results of each group of comparative tests; the percentage difference includes the percentage difference of vehicle coasting distance, coasting time, braking distance, and braking time.

[0010] S3: Based on the preset mapping relationship between the percentage difference and the evaluation standard, the percentage difference between the coasting test and the braking test of each group of vehicles is weighted and calculated, and then the deceleration consistency of the vehicles is comprehensively evaluated and analyzed.

[0011] Based on the aforementioned technical methods, vehicle coasting and braking tests are conducted to obtain more comprehensive and realistic deceleration scenarios, including braking deceleration and coasting deceleration. By differentiating the test results of each group of comparative tests, the impact of energy recovery intensity on vehicle coasting deceleration and braking deceleration can be observed intuitively.

[0012] The pre-defined mapping relationship between the percentage difference and the evaluation criteria provides a clear quantitative indicator for the percentage difference of each test result, making the originally vague range data more precise, easier to understand and operate. Different weights are assigned to the degree of influence of different test items on the vehicle deceleration consistency, which can more accurately evaluate the vehicle's deceleration consistency under different test conditions. This enables drivers to accurately control the vehicle's deceleration, thereby effectively avoiding accidents caused by improper braking in emergency situations.

[0013] Furthermore, the multi-group comparative test of the vehicle in S1 specifically includes conducting the comparative tests of each group based on multiple energy recovery influencing factors using the controlled variable method.

[0014] Based on the above technical means, and considering multiple factors affecting energy recovery, experiments using the controlled variable method can determine the influence of energy recovery intensity on the deceleration differences during sliding deceleration and braking deceleration under various factors. Furthermore, the controlled variable method can improve the reliability and repeatability of the results of sliding tests and braking deceleration.

[0015] Furthermore, step S1 specifically includes the following sub-steps:

[0016] S11: Based on the vehicle's battery charge state, motor operating temperature, and battery temperature, the vehicle test conditions are set differently using the controlled variable method so that the vehicle can perform three sets of coasting comparison tests and three sets of braking comparison tests respectively.

[0017] S12: Obtain the gliding time and gliding distance for each group of gliding comparison tests, and the braking time and braking distance for each group of braking comparison tests.

[0018] Based on the aforementioned technical means, by considering three key factors affecting energy recovery efficiency—the vehicle's battery charge state, motor operating temperature, and battery temperature—this method can comprehensively evaluate the consistency of braking and coasting deceleration in electric vehicles. Furthermore, by using the controlled variable method to differentiate the vehicle test factors, the impact of different factors on deceleration consistency can be measured more accurately, resulting in more precise test results. Conducting three sets of coasting comparison tests and three sets of braking comparison tests provides abundant data, helping to reveal the comprehensive impact of different factors on deceleration performance.

[0019] Further, the test conditions in S1 include: a first test condition, a second test condition, and a third test condition; the first test condition: the variable is the vehicle's battery state of charge, and the irrelevant variables are the vehicle's motor operating temperature and the vehicle's battery temperature; the second test condition: the variable is the vehicle's motor operating temperature, and the irrelevant variables are the vehicle's battery state of charge and the vehicle's battery temperature; the third test condition: the variable is the vehicle's battery temperature, and the irrelevant variables include the vehicle's battery state of charge and the vehicle's motor operating temperature; so that the vehicle can perform three sets of coasting comparison tests and three sets of braking comparison tests under the three test conditions respectively.

[0020] Based on the above technical means, the variables and irrelevant variables in the experimental process were determined, and the effects of the energy recovery system on the deceleration differences in sliding deceleration and braking deceleration were determined for each vehicle, including the battery charge state, motor operating temperature, and battery temperature.

[0021] Furthermore, the gliding comparison test described in each group specifically includes the following sub-steps:

[0022] S121: Based on the test conditions described above, set up two sets of sliding test conditions with different variable values ​​and the same irrelevant variable values ​​to conduct a control variable sliding comparison test;

[0023] S122: Under each coasting test condition, when the vehicle speed exceeds the preset first coasting speed, acceleration is stopped in order to coast;

[0024] S123: When the vehicle's coasting speed decreases to the first coasting speed, timing and measurement of the vehicle's coasting distance begin. When the vehicle decelerates to the second coasting speed, timing and measurement of the vehicle's coasting distance end, in order to obtain the first coasting time and first coasting distance for each group of vehicles.

[0025] S124: Change the variable values ​​corresponding to each of the test conditions, and repeat steps S122 to S123 to obtain the second coasting time and the second coasting distance of the vehicle.

[0026] Furthermore, step S2 further includes the following sub-steps:

[0027] S21: Differentiate the test results of the coasting comparison test for each group to obtain the percentage difference in coasting time and coasting distance for each group of vehicles.

[0028] Based on the above technical means, the influence of the energy recovery system on the coasting deceleration process can be observed intuitively by the percentage difference in coasting time and coasting distance of each group of vehicles, so as to obtain the difference in coasting time and coasting distance during the coasting deceleration process.

[0029] Furthermore, in S21, the formulas for calculating the percentage difference in coasting time and the percentage difference in coasting distance for each group of vehicles are as follows:

[0030] The percentage difference in gliding time is calculated as shown in the following formula:

[0031] Where: i represents the i-th group of gliding comparison tests, M i T represents the percentage difference in gliding time in the i-th group of gliding comparison tests. 滑i T′ represents the first or second sliding time measured when the variable mentioned in the i-th group of sliding comparison tests is the smaller value during the comparison test process. 滑i This indicates the first sliding time or the second sliding time measured when the variable mentioned in the i-th group of sliding comparison tests is the larger value during the comparison test process;

[0032] The percentage difference in gliding distance is calculated as shown in the following formula:

[0033] Where: i represents the i-th group of gliding comparison tests, H i S represents the percentage difference in sliding distance in the i-th group of sliding comparison tests. 滑i S′ represents the first or second sliding distance measured when the variable in the i-th group of sliding comparison tests is the smaller value during the comparison test process. 滑i This indicates the second sliding distance or the first sliding distance measured when the variable mentioned in the i-th group of sliding comparison tests is a larger value during the comparison test process.

[0034] Furthermore, the braking comparison test described in each group specifically includes the following sub-steps:

[0035] S121': Based on the test conditions described above, two sets of braking test conditions with different variable values ​​and the same irrelevant variable values ​​are set to conduct a control variable braking comparison test;

[0036] S122': Under each braking test condition, when the vehicle speed is higher than the preset first braking speed, acceleration is stopped, the brake pedal opening is adjusted to the target brake pedal opening to perform braking, and the target brake pedal opening is maintained.

[0037] S123': When the vehicle speed decreases to the first braking speed, start timing and start measuring the vehicle braking distance. When the vehicle decelerates to the second braking speed, stop timing and stop measuring the vehicle braking distance to obtain the first braking time and second braking distance of each group of vehicles.

[0038] S124': Change the value of the variable and repeat steps S122' to S123' to obtain the second braking time and second braking distance of the vehicle.

[0039] Furthermore, step S2 also includes the following sub-steps:

[0040] S22: Differentiate the test results of the braking comparison test for each group to obtain the percentage difference in braking time and braking distance for each group of vehicles.

[0041] Based on the above technical means, the influence of the energy recovery system on the braking deceleration process can be observed intuitively by the percentage difference in braking time and braking distance of each group of vehicles, so as to obtain the difference in braking time and braking distance during the braking deceleration process.

[0042] Furthermore, in S22, the formulas for calculating the percentage difference in braking time and the percentage difference in braking distance among the various groups of vehicles are as follows:

[0043] The percentage difference in braking time is calculated as shown in the following formula:

[0044] Where: i represents the i-th group of braking comparison tests, M′ i T represents the percentage difference in braking time in the i-th group of braking comparison tests. 制i T′ represents the first or second braking time measured when the variable mentioned in the i-th group of braking comparison tests is the smaller value during the comparison test process. 制i This indicates the second braking time or the first braking time measured when the variable mentioned in the i-th group of braking comparison tests is a larger value during the comparison test process;

[0045] The percentage difference in braking distance is calculated as shown in the following formula:

[0046] Where: i represents the i-th group of braking comparison tests, H′ iS represents the percentage difference in braking distance in the i-th group of braking comparison tests. 制i S′ represents the first braking distance or the second braking distance measured when the variable mentioned in the i-th group of braking comparison tests is the smaller value during the comparison test process. 制i This indicates the second braking distance or the first braking distance measured when the variable mentioned in the i-th group of gliding comparison tests is a larger value during the comparison test process.

[0047] The beneficial effects of this invention are:

[0048] 1. Conducting vehicle coasting and braking tests ensures comprehensive data that better reflects real-world deceleration scenarios, including braking and coasting deceleration. By differentiating the test results from each group of comparative tests, the impact of energy recovery intensity on vehicle coasting deceleration and braking deceleration can be clearly observed.

[0049] 2. The pre-defined mapping relationship between the percentage difference and the evaluation criteria provides a clear quantitative indicator for the percentage difference of each test result, making the originally vague range data more precise and easier to understand and operate; different weights are assigned to the degree of influence of different test items on the vehicle deceleration consistency, which can more accurately evaluate the vehicle's deceleration consistency under different test conditions, thereby enabling drivers to accurately control the vehicle's deceleration and effectively avoid accidents caused by improper braking in emergency situations. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the overall process of an embodiment of the present invention;

[0051] Figure 2 This is a schematic diagram of the process for each group of comparative experiments of the present invention;

[0052] Figure 3 This is a schematic diagram of the process for the various groups of gliding comparison tests of the present invention;

[0053] Figure 4 This is a schematic diagram of the process for the braking comparison test of each group in this invention;

[0054] Figure 5 This is a schematic diagram of the processing flow of the comparative experimental results of the present invention. Detailed Implementation

[0055] The embodiments of the present invention will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention and not for limiting the scope of protection of the present invention.

[0056] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0057] like Figure 1 As shown, a method for testing and evaluating the consistency of braking and coasting deceleration in electric vehicles includes the following steps:

[0058] S1: Conduct multiple sets of comparative tests on the vehicle; the tests include vehicle coasting tests and vehicle braking tests, and the test results include the vehicle's coasting time, coasting distance, braking time and braking distance;

[0059] S2: Perform differential processing on the test results of each group of comparative tests to obtain the percentage difference of the test results of each group of comparative tests; the percentage difference includes the percentage difference of vehicle coasting distance, coasting time, braking distance, and braking time.

[0060] S3: Based on the preset mapping relationship between the percentage difference and the evaluation standard, the percentage difference between the coasting test and the braking test of each group of vehicles is weighted and calculated, and then the deceleration consistency of the vehicles is comprehensively evaluated and analyzed.

[0061] Conducting vehicle coasting and braking tests provides comprehensive data that better reflects real-world deceleration scenarios, including braking and coasting deceleration. By differentiating the test results from each group of comparative tests, the impact of energy recovery intensity on vehicle coasting deceleration and braking deceleration can be observed directly.

[0062] The pre-defined mapping relationship between the percentage difference and the evaluation criteria provides a clear quantitative indicator for the percentage difference of each test result, making the originally vague range data more precise, easier to understand and operate. Different weights are assigned to the degree of influence of different test items on the vehicle deceleration consistency, which can more accurately evaluate the vehicle's deceleration consistency under different test conditions. This enables drivers to accurately control the vehicle's deceleration, thereby effectively avoiding accidents caused by improper braking in emergency situations.

[0063] In this embodiment, the multi-group comparative test of the vehicle in S1 specifically includes conducting the comparative tests of each group based on multiple energy recovery influencing factors using the controlled variable method. By conducting experiments based on multiple energy recovery influencing factors using the controlled variable method, the influence of energy recovery intensity on the deceleration differences during sliding deceleration and braking deceleration under each energy recovery influencing factor can be determined. Furthermore, the controlled variable method can improve the reliability and repeatability of the sliding test and braking deceleration results.

[0064] like Figure 2 As shown, in this embodiment, step S1 specifically includes the following sub-steps:

[0065] S11: Based on the vehicle's battery charge state, motor operating temperature, and battery temperature, the vehicle test conditions are set differently using the controlled variable method so that the vehicle can perform three sets of coasting comparison tests and three sets of braking comparison tests respectively.

[0066] S12: Obtain the gliding time and gliding distance for each group of gliding comparison tests, and the braking time and braking distance for each group of braking comparison tests.

[0067] By considering three key factors affecting energy recovery efficiency—the vehicle's battery state of charge, motor operating temperature, and battery temperature—this method can comprehensively evaluate the consistency of braking and coasting deceleration in electric vehicles. Furthermore, by using the controlled variable method to differentiate vehicle test factors, the impact of different factors on deceleration consistency can be measured more accurately, resulting in more precise test results. Three sets of coasting comparison tests and three sets of braking comparison tests provide abundant data, helping to reveal the comprehensive impact of different factors on deceleration performance.

[0068] In this embodiment, the test conditions in S1 include: a first test condition, a second test condition, and a third test condition; the first test condition: the variable is the vehicle's battery charge state, and the irrelevant variables are the vehicle's motor operating temperature and the vehicle's battery temperature; the second test condition: the variable is the vehicle's motor operating temperature, and the irrelevant variables are the vehicle's battery charge state and the vehicle's battery temperature; the third test condition: the variable is the vehicle's battery temperature, and the irrelevant variables include the vehicle's battery charge state and the vehicle's motor operating temperature; so that the vehicle can perform three sets of coasting comparison tests and three sets of braking comparison tests under the three test conditions respectively.

[0069] The variables and extraneous variables in the experimental process were identified, and the effects of the energy recovery system on the deceleration differences during sliding deceleration and braking deceleration were determined based on the battery charge state, motor operating temperature, and battery temperature of each vehicle.

[0070] Preferably, when the vehicle's battery state of charge is a variable, it is adjusted to 5%–10% and 90%–100% respectively, while the irrelevant variable vehicle motor operating temperature is 80°C–100°C and the irrelevant variable vehicle battery temperature is 35°C–50°C; when the vehicle's motor operating temperature is a variable, it is adjusted to below 80°C and above 100°C respectively, while the irrelevant variable vehicle battery state of charge is 45%–55% and the irrelevant variable vehicle battery temperature is 35°C–50°C; when the vehicle's battery temperature is a variable, it is adjusted to 10°C–35°C and above 50°C respectively, while the irrelevant variable vehicle battery state of charge is 45%–55% and the irrelevant variable vehicle motor operating temperature is 80°C–100°C.

[0071] like Figure 3 As shown, the gliding comparison test for each group specifically includes the following sub-steps:

[0072] S121: Based on the test conditions described above, set up two sets of sliding test conditions with different variable values ​​and the same irrelevant variable values ​​to conduct a control variable sliding comparison test;

[0073] S122: Under each coasting test condition, when the vehicle speed exceeds the preset first coasting speed, acceleration is stopped in order to coast;

[0074] S123: When the vehicle's coasting speed decreases to the first coasting speed, timing and measurement of the vehicle's coasting distance begin. When the vehicle decelerates to the first coasting speed, timing and measurement of the vehicle's coasting distance end, in order to obtain the first coasting time and first coasting distance for each group of vehicles.

[0075] S124: Change the variable values ​​corresponding to each of the test conditions, and repeat steps S122 to S123 to obtain the second coasting time and the second coasting distance of the vehicle.

[0076] Preferably, the gliding test includes two sets of gliding tests. In the first set of gliding tests, the first gliding speed is 120 km / h and the second gliding speed is 80 km / h. In the second set of gliding tests, the first gliding speed is 60 km / h and the second gliding speed is 10 km / h.

[0077] like Figure 5 As shown, in this embodiment, the test results of each group of coasting comparison tests are differentiated to obtain the percentage difference in coasting time and coasting distance for each group of vehicles. The percentage difference in coasting time and coasting distance for each group of vehicles allows for a direct observation of the impact of the energy recovery system on the coasting deceleration process during operation, thus revealing the differences in coasting time and coasting distance during the deceleration process.

[0078] In this embodiment, the calculation formulas for the percentage difference in coasting time and the percentage difference in coasting distance among the various groups of vehicles in step S21 are as follows:

[0079] The percentage difference in gliding time is calculated as shown in the following formula:

[0080] Where: i represents the i-th group of gliding comparison tests, M i T represents the percentage difference in gliding time in the i-th group of gliding comparison tests. 滑i T′ represents the first or second sliding time measured when the variable mentioned in the i-th group of sliding comparison tests is the smaller value during the comparison test process. 滑i This indicates the first sliding time or the second sliding time measured when the variable mentioned in the i-th group of sliding comparison tests is the larger value during the comparison test process;

[0081] The percentage difference in gliding distance is calculated as shown in the following formula:

[0082] Where: i represents the i-th group of gliding comparison tests, H i S represents the percentage difference in sliding distance in the i-th group of sliding comparison tests. 滑i S′ represents the first or second sliding distance measured when the variable in the i-th group of sliding comparison tests is the smaller value during the comparison test process. 滑i This indicates the second sliding distance or the first sliding distance measured when the variable mentioned in the i-th group of sliding comparison tests is a larger value during the comparison test process.

[0083] like Figure 4 As shown, in this embodiment, the braking comparison test for each group specifically includes the following sub-steps:

[0084] S121': Based on the test conditions described above, two sets of braking test conditions with different variable values ​​and the same irrelevant variable values ​​are set to conduct a control variable braking comparison test;

[0085] S122': Under each braking test condition, when the vehicle speed is higher than the preset first braking speed, acceleration is stopped, the brake pedal opening is adjusted to the target brake pedal opening to perform braking, and the target brake pedal opening is maintained.

[0086] S123': When the vehicle speed decreases to the first braking speed, start timing and start measuring the vehicle braking distance. When the vehicle decelerates to the second braking speed, stop timing and stop measuring the vehicle braking distance to obtain the first braking time and second braking distance of each group of vehicles.

[0087] S124': Change the value of the variable and repeat steps S122' to S123' to obtain the second braking time and second braking distance of the vehicle.

[0088] Preferably, the braking test includes two sets of braking tests. In the first set of braking tests, the first braking speed is 100 km / h, the second braking speed is 0, and the target brake pedal opening is 25%. In the second set of braking tests, the first braking speed is 50 km / h, the second braking speed is 0, and the target brake pedal opening is 50%.

[0089] like Figure 5 As shown, in this embodiment, step S2 further includes the following sub-steps:

[0090] S22: The test results of the braking comparison tests for each group are processed to obtain the percentage difference in braking time and braking distance for each group of vehicles. Based on the above technical means, the impact of the energy recovery system on the braking deceleration process during operation can be observed intuitively through the percentage difference in braking time and braking distance for each group of vehicles, thus obtaining the differences in braking time and braking distance during the braking deceleration process.

[0091] In this embodiment, the calculation formulas for the percentage difference in braking time and percentage difference in braking distance among the various groups of vehicles in step S22 are as follows:

[0092] The percentage difference in braking time is calculated as shown in the following formula:

[0093] Where: i represents the i-th group of braking comparison tests, M′ i T represents the percentage difference in braking time in the i-th group of braking comparison tests. 制iT′ represents the first or second braking time measured when the variable mentioned in the i-th group of braking comparison tests is the smaller value during the comparison test process. 制i This indicates the second braking time or the first braking time measured when the variable mentioned in the i-th group of braking comparison tests is a larger value during the comparison test process;

[0094] The percentage difference in braking distance is calculated as shown in the following formula:

[0095] Where: i represents the i-th group of braking comparison tests, H′ i S represents the percentage difference in braking distance in the i-th group of braking comparison tests. 制i S′ represents the first braking distance or the second braking distance measured when the variable mentioned in the i-th group of braking comparison tests is the smaller value during the comparison test process. 制i This indicates the second braking distance or the first braking distance measured when the variable mentioned in the i-th group of gliding comparison tests is a larger value during the comparison test process.

[0096] Preferably, the mapping relationship in S3 specifically includes a negative correlation between the percentage difference in vehicle coasting deceleration and braking deceleration processes and the evaluation criteria.

[0097] Preferably, the weighted algorithm in S3 includes assigning weights to each test item based on its impact on the vehicle's deceleration consistency, thereby evaluating the vehicle's deceleration consistency. Assigning different weights to different test items based on their impact on the vehicle's deceleration consistency allows for a more accurate evaluation of the vehicle's deceleration consistency under different test conditions.

[0098] In summary, the implementation process of a test and evaluation method for the consistency of braking and coasting deceleration of electric vehicles includes the following steps:

[0099] Step 1: Based on the vehicle's battery charge state, motor operating temperature, and battery temperature, the vehicle test conditions are set differently using the controlled variable method, so that the vehicle can perform three sets of coasting comparison tests and three sets of braking comparison tests to obtain the test results of each set of comparison tests.

[0100] Step Two: Determine the respective test conditions, including: Test Condition 1, Test Condition 2, and Test Condition 3; Test Condition 1: The variable is the vehicle's battery state of charge, and the irrelevant variables are the vehicle's motor operating temperature and the vehicle's battery temperature; Test Condition 2: The variable is the vehicle's motor operating temperature, and the irrelevant variables are the vehicle's battery state of charge and the vehicle's battery temperature; Test Condition 3: The variable is the vehicle's battery temperature, and the irrelevant variables include the vehicle's battery state of charge and the vehicle's motor operating temperature; so that the vehicle can perform three sets of coasting comparison tests and three sets of braking comparison tests under the three test conditions respectively.

[0101] Step 3: Conduct coasting and braking tests on each comparative test group, including measuring the vehicle's coasting time, coasting distance, braking time and braking distance under different variable conditions;

[0102] Step 4: Compare the differences in gliding time, gliding distance, braking time, and braking distance among the test results of each group.

[0103] Step 5: Based on the pre-defined mapping relationship between the percentage difference and the evaluation criteria, and using a weighted algorithm for each test item, obtain the impact of each influencing factor on the consistency of vehicle deceleration;

[0104] Step Six: Obtain the impact of the energy recovery system's operation on the vehicle's deceleration consistency under the vehicle's battery charge state, motor operating temperature, and battery temperature variables, and then evaluate the deceleration consistency during the vehicle's coasting and braking processes.

[0105] The above embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention.

Claims

1. A method for testing and evaluating the consistency of braking and coasting deceleration in electric vehicles, characterized in that, Includes the following steps: S1: Conduct multiple sets of comparative tests on the vehicle; the tests include vehicle coasting tests and vehicle braking tests, and the test results include the vehicle's coasting time, coasting distance, braking time and braking distance; The S1 process of conducting multiple sets of comparative tests on the vehicle specifically includes conducting each set of comparative tests based on multiple energy recovery influencing factors using the controlled variable method. Step S1 specifically includes the following sub-steps: S11: Based on the vehicle's battery charge state, motor operating temperature, and battery temperature, the vehicle test conditions are set differently using the controlled variable method so that the vehicle can perform three sets of coasting comparison tests and three sets of braking comparison tests respectively. S12: Obtain the gliding time and gliding distance for each group of gliding comparison tests, and the braking time and braking distance for each group of braking comparison tests; The test conditions in S1 include: a first test condition, a second test condition, and a third test condition; First test condition: The variable is the vehicle's battery state of charge, and the irrelevant variables are the vehicle's motor operating temperature and the vehicle's battery temperature; Second test condition: The variable is the vehicle's motor operating temperature, and the irrelevant variables are the vehicle's battery state of charge and the vehicle's battery temperature; Third test condition: The variable is the vehicle's battery temperature, and the irrelevant variables include the vehicle's battery state of charge and the vehicle's motor operating temperature; so that the vehicle can perform three sets of coasting comparison tests and three sets of braking comparison tests under the three test conditions respectively. S2: Perform differential processing on the test results of each group of comparative tests to obtain the percentage difference of the test results of each group of comparative tests; the percentage difference includes the percentage difference of vehicle coasting distance, coasting time, braking distance, and braking time. S3: Based on the preset mapping relationship between the percentage difference and the evaluation standard, the percentage difference between the coasting test and the braking test of each group of vehicles is weighted and calculated, and then the deceleration consistency of the vehicles is comprehensively evaluated and analyzed.

2. The method for testing and evaluating the consistency of braking and coasting deceleration in electric vehicles according to claim 1, characterized in that, The gliding comparison test in each group in S12 specifically includes the following sub-steps: S121: Based on the test conditions described above, set up two sets of braking test conditions with different variable values ​​and the same irrelevant variable values ​​to conduct a control variable braking comparison test. S122: Under each coasting test condition, when the vehicle speed exceeds the preset first coasting speed, acceleration is stopped in order to coast; S123: When the vehicle's coasting speed decreases to the first coasting speed, timing and measurement of the vehicle's coasting distance begin. When the vehicle decelerates to the second coasting speed, timing and measurement of the vehicle's coasting distance end, in order to obtain the first coasting time and first coasting distance for each group of vehicles. S124: Change the variable values ​​corresponding to each of the test conditions, and repeat steps S122 to S123 to obtain the second coasting time and the second coasting distance of the vehicle.

3. The method for testing and evaluating the consistency of braking and coasting deceleration in electric vehicles according to claim 2, characterized in that, S2 includes the following sub-steps: S21: Differentiate the test results of the coasting comparison test for each group to obtain the percentage difference in coasting time and coasting distance for each group of vehicles.

4. The method for testing and evaluating the consistency of braking and coasting deceleration in electric vehicles according to claim 3, characterized in that, In step S21, the formulas for calculating the percentage difference in coasting time and the percentage difference in coasting distance for each group of vehicles are as follows: The percentage difference in gliding time is calculated as shown in the following formula: Where: i represents the i-th group of gliding comparison tests, This represents the percentage difference in gliding time in the i-th group of gliding comparison tests. This indicates the first or second gliding time measured when the variable mentioned in the i-th group of gliding comparison tests is the smaller value during the comparison test process. This indicates the first or second gliding time measured when the variable mentioned in the i-th group of gliding comparison tests is the larger value during the comparison test process; The percentage difference in gliding distance is calculated as shown in the following formula: Where: i represents the i-th group of gliding comparison tests, This represents the percentage difference in gliding distance in the i-th group of gliding comparison tests. This indicates the first or second gliding distance measured when the variable mentioned in the i-th group of gliding comparison tests is the smaller value during the comparison test process. This indicates the second gliding distance or the first gliding distance measured when the variable mentioned in the i-th group of gliding comparison tests is a larger value during the comparison test process.

5. The method for testing and evaluating the consistency of braking and coasting deceleration in electric vehicles according to claim 1, characterized in that, The braking comparison test in each group in S12 specifically includes the following sub-steps: S121': Based on the test conditions described above, two sets of braking test conditions with different variable values ​​and the same irrelevant variable values ​​are set to conduct a control variable braking comparison test; S122': Under each braking test condition, when the vehicle speed is higher than the preset first braking speed, acceleration is stopped, the brake pedal opening is adjusted to the target brake pedal opening to perform braking, and the target brake pedal opening is maintained. S123': When the vehicle speed decreases to the first braking speed, start timing and start measuring the vehicle braking distance. When the vehicle decelerates to the second braking speed, stop timing and stop measuring the vehicle braking distance to obtain the first braking time and first braking distance of each group of vehicles. S124': Change the value of the variable and repeat steps S122'~S123' to obtain the second braking time and second braking distance of the vehicle.

6. The method for testing and evaluating the consistency of braking and coasting deceleration in electric vehicles according to claim 5, characterized in that, Step S2 further includes the following sub-steps: S22: Differentiate the test results of the braking comparison test for each group to obtain the percentage difference in braking time and braking distance for each group of vehicles.

7. The method for testing and evaluating the consistency of braking and coasting deceleration in electric vehicles according to claim 6, characterized in that, In step S22, the formulas for calculating the percentage difference in braking time and the percentage difference in braking distance for each group of vehicles are as follows: The percentage difference in braking time is calculated as shown in the following formula: Where: i represents the i-th group of braking comparison tests. This represents the percentage difference in braking time in the i-th group of braking comparison tests. This indicates the first braking time or the second braking time measured when the variable mentioned in the i-th group of braking comparison tests is the smaller value during the comparison test process. This indicates the second braking time or the first braking time measured when the variable mentioned in the i-th group of braking comparison tests is a larger value during the comparison test process; The percentage difference in braking distance is calculated as shown in the following formula: Where: i represents the i-th group of braking comparison tests, This represents the percentage difference in braking distance in the i-th group of braking comparison tests. This indicates the first braking distance or the second braking distance measured when the variable mentioned in the i-th group of braking comparison tests is the smaller value during the comparison test process. This indicates the second braking distance or the first braking distance measured when the variable mentioned in the i-th group of gliding comparison tests is a larger value during the comparison test process.

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