Method for testing and evaluating consistency of braking and sliding deceleration of electric vehicle

Abstract

The invention relates to a method for testing and evaluating consistency of braking and sliding deceleration of an electric vehicle. The method comprises the following steps: S1, carrying out multiple groups of comparison tests on the vehicle; the test comprises a vehicle sliding test and a vehicle braking test, and the test result comprises the sliding time, the sliding distance, the braking time and the braking distance of the vehicle; s2, differentiating the test results of each group of comparison tests to obtain the difference percentage of the test results of each group of comparison tests; the difference percentage comprises a sliding distance difference percentage, a sliding time difference percentage, a braking distance difference percentage and a braking time difference percentage of the vehicle; and S3, according to a preset mapping relation between the difference percentage and an evaluation standard, performing weighted calculation on the difference percentage of each group of vehicle sliding tests and vehicle braking tests, and further performing comprehensive evaluation analysis on the deceleration consistency of the vehicles. According to the invention, the braking deceleration consistency and the sliding deceleration consistency of the vehicle can be measured and evaluated.

Description

Technical Field

[0001] The invention relates to the technical field of automobile testing, and in particular to a method for testing and evaluating the consistency of braking and coasting deceleration of an electric vehicle. Background Art

[0002] Electric vehicles have an energy recovery system, which has a significant impact on the deceleration performance of electric vehicles. The energy recovery system converts the kinetic energy generated during the coasting deceleration process and the braking deceleration process into electrical energy, thereby improving energy utilization efficiency and increasing the range. During the energy recovery process, there will be a noticeable dragging feeling when the vehicle decelerates. This is because electric vehicles will produce additional deceleration during energy recovery, which in turn affects the braking distance and coasting distance of electric vehicles, making it easy for drivers to make misjudgments during the deceleration process, resulting in vehicle accidents.

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

[0004] In the prior art, for example, the invention patent with authorization publication number CN118810451A, “A coordinated control system and method for electric vehicle wire-controlled braking energy recovery”, aims to reduce the discomfort of drivers and passengers during energy recovery by coordinating control of multiple active safety functions and optimizing braking response. However, it does not test and evaluate the deceleration differences caused by the operation of the energy recovery system. Summary of the invention

[0005] The object of the present invention is to provide a method for testing and evaluating the consistency of braking and coasting deceleration of an electric vehicle, so as to solve the problem of deceleration differences in the deceleration process caused by the operation of an energy recovery system in the prior art.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A method for testing and evaluating the consistency of braking and coasting deceleration of an electric vehicle comprises the following steps:

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

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

[0010] S3: Based on the preset mapping relationship between the difference percentage and the evaluation standard, a weighted calculation is performed on the difference percentage of each group of vehicle coasting tests and vehicle braking tests, and then a comprehensive evaluation and analysis of the vehicle's deceleration consistency is performed.

[0011] According to the above-mentioned technical means, the vehicle is subjected to a vehicle coasting test and a vehicle braking test, so that the measured data is more comprehensive and more in line with the deceleration scenarios in actual scenarios, including braking deceleration and sliding deceleration; by performing differentiated processing on the test results of each group of comparative tests, it is possible to intuitively observe the impact of energy recovery intensity on the vehicle's coasting deceleration process, as well as the impact on the vehicle's braking deceleration process.

[0012] The preset mapping relationship between the difference percentage and the evaluation standard provides a clear quantitative indicator for the difference percentage 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's deceleration consistency, which can more accurately evaluate the vehicle's deceleration consistency under different test conditions, thereby enabling the driver to accurately control the vehicle's deceleration, thereby effectively avoiding accidents caused by improper braking in emergency situations.

[0013] Furthermore, the performing of multiple groups of comparative tests on the vehicle in S1 specifically includes performing each group of comparative tests by a control variable method based on multiple energy recovery influencing factors.

[0014] According to the above-mentioned technical means, based on multiple energy recovery influencing factors, experiments are carried out through the control variable method, which can determine the influence of energy recovery intensity on the deceleration difference of sliding deceleration and the deceleration difference in braking deceleration under various energy recovery influencing factors, and the control variable method can improve the reliability and repeatability of sliding test and braking deceleration results.

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

[0016] S11: Based on the battery charge state of the vehicle, the motor operating temperature of the vehicle, and the battery temperature of the vehicle, the vehicle test conditions are set differently by a control variable method, so that the vehicle can perform three groups of coasting comparison tests and three groups of braking comparison tests respectively;

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

[0018] According to the above technical means, by considering the three key factors affecting energy recovery efficiency, namely the vehicle's battery charge state, motor operating temperature and battery temperature, this method can comprehensively evaluate the braking and coasting deceleration consistency of electric vehicles; then the control variable method is used to differentiate the vehicle test factors, which can more accurately measure the impact of different factors on deceleration consistency, thereby obtaining more accurate test results; three groups of coasting comparison tests and three groups of braking comparison tests are conducted, which provide rich data and help reveal the comprehensive impact of different factors on deceleration performance.

[0019] Furthermore, 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 battery charge state of the vehicle, and the irrelevant variables are the motor operating temperature of the vehicle and the battery temperature of the vehicle; the second test condition: the variable is the motor operating temperature of the vehicle, and the irrelevant variables are the battery charge state of the vehicle and the battery temperature of the vehicle; the third test condition: the variable is the battery temperature of the vehicle, and the irrelevant variables include the battery charge state of the vehicle and the motor operating temperature of the vehicle; so that the vehicle can perform three groups of coasting comparison tests and three groups of braking comparison tests under the three test conditions.

[0020] According to the above technical means, the variables and irrelevant variables in the experimental process were determined, and it was possible to determine the different deceleration effects of the energy recovery system on sliding deceleration and braking deceleration under the battery charge state of each vehicle, the motor operating temperature of the vehicle and the battery temperature of the vehicle.

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

[0022] S121: Based on the test conditions, two groups of coasting test conditions with different variable values ​​and the same irrelevant variable values ​​are set to perform a controlled variable coasting comparison test;

[0023] S122: Under each coasting test condition, when the vehicle running speed is higher than a preset first coasting speed, the vehicle stops accelerating to coast;

[0024] S123: when the vehicle coasting speed decreases to the first coasting speed, start timing and start measuring the vehicle coasting distance, and when the vehicle decelerates to the second coasting speed, end timing and end measuring the vehicle coasting distance, so as to obtain the first coasting time and the first coasting distance of each group of vehicles;

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

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

[0027] S21: performing differentiation processing on the test results of the coasting comparison test of each group to obtain the coasting time difference percentage and the coasting distance difference percentage of each group of vehicles.

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

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

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

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

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

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

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

[0035] S121': based on the test conditions, setting two groups of braking test conditions with different variable values ​​and the same irrelevant variable values ​​to perform a control variable braking comparison test;

[0036] S122': Under each braking test condition, when the vehicle running speed is higher than the preset first braking speed, stop accelerating, adjust the brake pedal opening to the target brake pedal opening to perform braking, and maintain the target brake pedal opening;

[0037] S123': when the vehicle running speed is reduced to the first braking speed, start timing and start measuring the vehicle braking distance; when the vehicle is decelerated to the second braking speed, end timing and end measuring the vehicle braking distance, so as to obtain the first braking time and the second braking distance of each group of vehicles;

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

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

[0040] S22: performing differentiation processing on the test results of the braking comparison test of each group to obtain the braking time difference percentage and the braking distance difference percentage of each group of vehicles.

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

[0042] Furthermore, in S22, the calculation formulas for the braking time difference percentage and the braking distance difference percentage of each group of vehicles are as follows:

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

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

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

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

[0047] Beneficial effects of the present invention:

[0048] 1. Carry out vehicle coasting test and vehicle braking test to make the measured data more comprehensive and more in line with the deceleration scenarios in actual scenarios, including braking deceleration and sliding deceleration; by differentiating the test results of each group of comparative tests, it is possible to intuitively observe the impact of energy recovery intensity on the vehicle's coasting deceleration process and the impact on the vehicle's braking deceleration process.

[0049] 2. The preset mapping relationship between the difference percentage and the evaluation standard provides a clear quantitative indicator for the difference percentage of each test result, making the originally vague range data more accurate and easier to understand and operate; different weights are assigned to the degree of influence of different test items on the vehicle's deceleration consistency, which can more accurately evaluate the vehicle's deceleration consistency under different test conditions, thereby enabling the driver to accurately control the vehicle's deceleration, thereby effectively avoiding accidents caused by improper braking in emergency situations. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0051] Figure 2 It is a schematic diagram of the flow chart of each group of comparative experiments of the present invention;

[0052] Figure 3 It is a schematic diagram of the flow chart of each group of sliding comparison test of the present invention;

[0053] Figure 4 It is a schematic diagram of the flow chart of each group of brake comparison tests of the present invention;

[0054] Figure 5 It is a schematic diagram of the processing flow of each group of comparative experimental results of the present invention. DETAILED DESCRIPTION

[0055] The following will describe the embodiments of the present invention 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 contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways 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, 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 illustrations of the basic concept of the present invention, and thus the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

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

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

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

[0060] S3: Based on the preset mapping relationship between the difference percentage and the evaluation standard, a weighted calculation is performed on the difference percentage of each group of vehicle coasting tests and vehicle braking tests, and then a comprehensive evaluation and analysis of the vehicle's deceleration consistency is performed.

[0061] The vehicle is subjected to a coasting test and a braking test, so that the measured data is more comprehensive and more in line with the deceleration scenarios in actual scenarios, including braking deceleration and sliding deceleration. By performing differentiated processing on the test results of each group of comparative tests, the impact of energy recovery intensity on the vehicle's coasting deceleration process and the impact on the vehicle's braking deceleration process can be intuitively observed.

[0062] The preset mapping relationship between the difference percentage and the evaluation standard provides a clear quantitative indicator for the difference percentage 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's deceleration consistency, which can more accurately evaluate the vehicle's deceleration consistency under different test conditions, thereby enabling the driver to accurately control the vehicle's deceleration, thereby effectively avoiding accidents caused by improper braking in emergency situations.

[0063] In this embodiment, the multiple groups of comparative tests on the vehicle in S1 specifically include performing the comparative tests on each group by a control variable method based on multiple energy recovery influencing factors. Based on multiple energy recovery influencing factors, the control variable method is used to perform experiments, so that the influence of energy recovery intensity on the deceleration difference of sliding deceleration and the deceleration difference in braking deceleration under each energy recovery influencing factor can be determined, and the control 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 battery charge state of the vehicle, the motor operating temperature of the vehicle, and the battery temperature of the vehicle, the vehicle test conditions are set differently by a control variable method, so that the vehicle can perform three groups of coasting comparison tests and three groups of braking comparison tests respectively;

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

[0067] By considering the three key factors affecting energy recovery efficiency, namely the vehicle's battery charge state, motor operating temperature and battery temperature, this method can comprehensively evaluate the braking and coasting deceleration consistency of electric vehicles; then using the control variable method to differentiate the vehicle test factors, the impact of different factors on deceleration consistency can be more accurately measured, thereby obtaining more accurate test results; three groups of coasting comparison tests and three groups of braking comparison tests were conducted, providing rich data, which helps 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 battery charge state of the vehicle, and the irrelevant variables are the motor operating temperature of the vehicle and the battery temperature of the vehicle; the second test condition: the variable is the motor operating temperature of the vehicle, and the irrelevant variables are the battery charge state of the vehicle and the battery temperature of the vehicle; the third test condition: the variable is the battery temperature of the vehicle, and the irrelevant variables include the battery charge state of the vehicle and the motor operating temperature of the vehicle; so that the vehicle can perform three groups of coasting comparison tests and three groups of braking comparison tests under the three test conditions.

[0069] The variables and irrelevant variables in the experimental process were determined, and the different effects of the energy recovery system on deceleration in sliding deceleration and braking deceleration under the battery charge state of each vehicle, the motor operating temperature of the vehicle and the battery temperature of the vehicle were determined.

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

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

[0072] S121: Based on the test conditions, two groups of coasting test conditions with different variable values ​​and the same irrelevant variable values ​​are set to perform a controlled variable coasting comparison test;

[0073] S122: Under each coasting test condition, when the vehicle running speed is higher than a preset first coasting speed, the vehicle stops accelerating to coast;

[0074] S123: when the vehicle coasting speed decreases to the first coasting speed, start timing and start measuring the vehicle coasting distance; when the vehicle decelerates to the first coasting speed, end timing and end measuring the vehicle coasting distance, so as to obtain the first coasting time and the first coasting distance of each group of vehicles;

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

[0076] Preferably, the taxiing test includes two groups of taxiing tests. In the first group of taxiing tests, the first taxiing speed is 120 km / h and the second taxiing speed is 80 km / h; in the second group of taxiing tests, the first taxiing speed is 60 km / h and the second taxiing speed is 10 km / h.

[0077] like Figure 5 As shown, in this embodiment, the test results of the coasting comparison test of each group are differentiated to obtain the coasting time difference percentage and the coasting distance difference percentage of each group of vehicles. The influence of the energy recovery system on the coasting deceleration process during the operation of the energy recovery system can be intuitively observed through the coasting time difference percentage and the coasting distance difference percentage of each group of vehicles, so as to obtain the coasting time difference and the coasting distance difference in the coasting deceleration process.

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

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

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

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

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

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

[0084] S121': based on the test conditions, setting two groups of braking test conditions with different variable values ​​and the same irrelevant variable values ​​to perform a control variable braking comparison test;

[0085] S122': Under each braking test condition, when the vehicle running speed is higher than the preset first braking speed, stop accelerating, adjust the brake pedal opening to the target brake pedal opening to perform braking, and maintain the target brake pedal opening;

[0086] S123': when the vehicle running speed is reduced to the first braking speed, start timing and start measuring the vehicle braking distance; when the vehicle is decelerated to the second braking speed, end timing and end measuring the vehicle braking distance, so as to obtain the first braking time and the second braking distance of each group of vehicles;

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

[0088] Preferably, the braking test includes two groups of braking tests, in which 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 group 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 also includes the following sub-steps:

[0090] S22: Performing differentiation processing on the test results of the braking comparison test of each group to obtain the braking time difference percentage and braking distance difference percentage of each group of vehicles. According to the above technical means, the influence of the energy recovery system on the braking deceleration process during the operation of the energy recovery system can be intuitively observed through the braking time difference percentage and braking distance difference percentage of each group of vehicles, so as to obtain the braking time difference and braking distance difference during the braking deceleration process.

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

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

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

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

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

[0096] Preferably, the mapping relationship in S3 specifically includes that the difference percentage between the vehicle's coasting deceleration and braking deceleration processes is negatively correlated with the evaluation criterion.

[0097] Preferably, the weighted algorithm in S3 includes assigning weights to each test item according to its influence on the vehicle deceleration consistency, thereby evaluating the vehicle deceleration consistency. Different weights are assigned to the influence of different test items on the vehicle deceleration consistency, so that the deceleration consistency of the vehicle under different test conditions can be evaluated more accurately.

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

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

[0100] Step 2: Determine the respective test conditions, the test conditions include: a first test condition, a second test condition and a third test condition; the first test condition: the variable is the battery charge state of the vehicle, and the irrelevant variables are the motor operating temperature of the vehicle and the battery temperature of the vehicle; the second test condition: the variable is the motor operating temperature of the vehicle, and the irrelevant variables are the battery charge state of the vehicle and the battery temperature of the vehicle; the third test condition: the variable is the battery temperature of the vehicle, and the irrelevant variables include the battery charge state of the vehicle and the motor operating temperature of the vehicle; so that the vehicle can perform three groups of coasting comparison tests and three groups of braking comparison tests under the three test conditions.

[0101] Step 3: Conduct coasting tests and braking tests on each comparison test group, including measuring the coasting time, coasting distance, braking time and braking distance of the vehicle under different variables;

[0102] Step 4: Compare the test results of each group by the taxiing time difference ratio, taxiing distance difference ratio, braking time difference ratio and braking distance difference ratio;

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

[0104] Step 6: Obtain the impact of the vehicle's battery charge state, the vehicle's motor operating temperature, and the vehicle's battery temperature variables on the vehicle's deceleration consistency when the energy recovery system is running, and then evaluate the vehicle's deceleration consistency during coasting and braking.

[0105] The above embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Any equivalent substitution or change made by a person skilled in the art based on the present invention is within the protection scope of the present invention.

Claims

1. A method for testing and evaluating the consistency of braking and coasting deceleration of electric vehicles, characterized in that: The following steps are involved: S1: performing multiple comparative tests on the vehicle; the tests include a vehicle coasting test and a vehicle braking test, and the test results include the vehicle's coasting time, coasting distance, braking time and braking distance; S2: performing differentiation processing on the test results of each group of comparative tests to obtain the difference percentage of the test results of each group of comparative tests; the difference percentage includes the vehicle's coasting distance difference percentage, coasting time difference percentage, braking distance difference percentage and braking time difference percentage; S3: Based on the preset mapping relationship between the difference percentage and the evaluation standard, a weighted calculation is performed on the difference percentage of each group of vehicle coasting tests and vehicle braking tests, and then a comprehensive evaluation and analysis of the vehicle's deceleration consistency is performed.

2. The electric vehicle braking and coasting deceleration consistency test and evaluation method according to claim 1 is characterized in that: The performing of multiple groups of comparative tests on the vehicle in S1 specifically includes performing each group of comparative tests by a control variable method based on multiple energy recovery influencing factors.

3. The electric vehicle braking and coasting deceleration consistency test and evaluation method according to claim 2 is characterized in that: The S1 step specifically includes the following sub-steps: S11: Based on the battery charge state of the vehicle, the motor operating temperature of the vehicle, and the battery temperature of the vehicle, the vehicle test conditions are set differently by a control variable method, so that the vehicle can perform three groups of coasting comparison tests and three groups of braking comparison tests respectively; S12: Obtaining the coasting time and the coasting distance of each group of coasting comparison tests, and the braking time and the braking distance of each group of braking comparison tests respectively.

4. The electric vehicle braking and coasting deceleration consistency test and evaluation method according to claim 3 is characterized in that: 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 battery charge state of the vehicle, and the irrelevant variables are the motor operating temperature of the vehicle and the battery temperature of the vehicle; the second test condition: the variable is the motor operating temperature of the vehicle, and the irrelevant variables are the battery charge state of the vehicle and the battery temperature of the vehicle; the third test condition: the variable is the battery temperature of the vehicle, and the irrelevant variables include the battery charge state of the vehicle and the motor operating temperature of the vehicle; so that the vehicle can perform three groups of coasting comparison tests and three groups of braking comparison tests under the three test conditions.

5. The electric vehicle braking and coasting deceleration consistency test and evaluation method according to claim 4 is characterized in that: The gliding comparison test of each group in S12 specifically includes the following sub-steps: S121: Based on the test conditions, two groups of braking test conditions with different variable values ​​and the same irrelevant variable values ​​are set to perform a control variable braking comparison test; S122: Under each coasting test condition, when the vehicle running speed is higher than a preset first coasting speed, the vehicle stops accelerating to coast; S123: when the vehicle coasting speed decreases to the first coasting speed, start timing and start measuring the vehicle coasting distance; when the vehicle decelerates to the second coasting speed, end timing and end measuring the vehicle coasting distance, so as to obtain the first coasting time and the first coasting distance of each group of vehicles; S124: Change the variable value corresponding to each of the test conditions, repeat steps S122 to S123, and obtain the second coasting time and second coasting distance of the vehicle.

6. The electric vehicle braking and coasting deceleration consistency test and evaluation method according to claim 5 is characterized in that: The S2 comprises the following sub-steps: S21: performing differentiation processing on the test results of the coasting comparison test of each group to obtain the coasting time difference percentage and the coasting distance difference percentage of each group of vehicles.

7. The electric vehicle braking and coasting deceleration consistency test and evaluation method according to claim 6 is characterized in that: In S21, the calculation formulas for the coasting time difference percentage and the coasting distance difference percentage of each group of vehicles are as follows: The taxi time difference percentage is calculated as shown in the following formula: Where: i represents the i-th group of sliding comparison test, M i represents the percentage difference of sliding time in the sliding comparison test of group i, T 滑i represents the first sliding time or the second sliding time measured when the variable in the i-th group of sliding comparison test is the smaller value in the comparison test process, T′ 滑i represents the first sliding time or the second sliding time measured when the variable in the i-th group of sliding comparison test is a larger value during the comparison test; The sliding distance difference percentage is calculated as shown in the following formula: Where: i represents the i-th group of sliding comparison test, H i represents the percentage difference in sliding distance in the sliding comparison test of group i, S 滑i represents the first sliding distance or the second sliding distance measured when the variable in the i-th group of sliding comparison test is the smaller value in the comparison test process, S′ 滑i It represents the second sliding distance or the first sliding distance measured when the variable in the i-th group of sliding comparison test is a larger value during the comparison test.

8. The electric vehicle braking and coasting deceleration consistency test and evaluation method according to claim 4 is characterized in that: The braking comparison test of each group in S12 specifically includes the following sub-steps: S121': based on the test conditions, setting two groups of braking test conditions with different variable values ​​and the same irrelevant variable values ​​to perform a control variable braking comparison test; S122': Under each braking test condition, when the vehicle running speed is higher than the preset first braking speed, stop accelerating, adjust the brake pedal opening to the target brake pedal opening to perform braking, and maintain the target brake pedal opening; S123': when the vehicle running speed is reduced to the first braking speed, start timing and start measuring the vehicle braking distance; when the vehicle is decelerated to the second braking speed, end timing and end measuring the vehicle braking distance, so as to obtain the first braking time and the second braking distance of each group of vehicles; S124': Change the value of the variable, and repeat steps S122' to S123' to obtain a second braking time and a second braking distance of the vehicle.

9. The electric vehicle braking and coasting deceleration consistency test and evaluation method according to claim 6 is characterized in that: The S2 step also includes the following sub-steps: S22: performing differentiation processing on the test results of the braking comparison test of each group to obtain the braking time difference percentage and the braking distance difference percentage of each group of vehicles.

10. The electric vehicle braking and coasting deceleration consistency test and evaluation method according to claim 9 is characterized in that: In S22, the calculation formulas for the braking time difference percentage and the braking distance difference percentage of each group of vehicles are as follows: The braking time difference percentage is calculated as shown in the following formula: Where: i represents the i-th group of braking comparison test, M′ i represents the percentage difference in braking time in the i-th group braking comparison test, T 制i represents the first braking time or the second braking time measured when the variable in the i-th group of braking comparison test is the smaller value during the comparison test, T′ 制i represents the second braking time or the first braking time measured when the variable in the i-th group of braking comparison test is the larger value during the comparison test; The braking distance difference percentage is calculated as shown in the following formula: Where: i represents the i-th group of braking comparison test, H′ i represents the percentage difference in braking distance in the i-th group braking comparison test, S 制i represents the first braking distance or the second braking distance measured when the variable in the i-th group of braking comparison test is the smaller value in the comparison test process, S′ 制i It represents the second braking distance or the first braking distance measured when the variable in the i-th group of coasting comparison test is a larger value during the comparison test.

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