Method, device, electronic device and storage medium for determining automobile drag coefficient

Abstract

The present invention discloses a method for determining the wind resistance coefficient of an automobile. According to the target size parameters and the windward area correction value of the target automobile, the target windward area of ​​the target automobile is obtained; according to the target passenger compartment parameters of the target automobile, the target passenger compartment volume of the target automobile is obtained; according to the target passenger compartment data and the air resistance correction value, the target air resistance of the target automobile is obtained; according to the target windward area, the target passenger compartment volume and the target air resistance, the target wind resistance coefficient of the target automobile is obtained. The method, device, electronic device and storage medium for determining the wind resistance coefficient of an automobile disclosed in the present invention can effectively improve the accuracy of the obtained wind resistance coefficient.

Description

Technical Field

[0001] The present invention relates to the field of automobile technology, and in particular to a method, device, electronic equipment and storage medium for determining a wind resistance coefficient of an automobile. Background Art

[0002] With the rapid development of vehicle technology, the application fields of automobiles are becoming wider and wider, and people's requirements for various aspects of automobile performance are constantly improving. They not only require good power performance of automobiles, but also riding space. The size of the wind resistance encountered by a car when driving on the road depends on its drag coefficient and the size of the windward area; and the projection area of ​​the car in the direction of travel basically determines the size of its lateral riding space; the wheelbase size determines the size of its longitudinal space; the product of the windward area and the wheelbase determines the size of the passenger compartment space.

[0003] In the prior art, during the design and development process of an automobile, out of consideration for power and fuel consumption performance, there are usually restrictions on air resistance at a specified speed to ensure the safety performance of the automobile. In this way, under the restriction of air resistance, it is necessary to adjust the relationship between the drag coefficient and the frontal area and the volume of the passenger compartment. In order to improve the efficiency of automobile design and development, it is necessary to calculate the drag coefficient of the automobile after determining the volume of the passenger compartment of the automobile so that the designed automobile meets the restriction of air resistance. The prior art usually obtains the drag coefficient through CAE simulation, but due to the complex road conditions, environmental climate and vehicle posture when the automobile is driving, there is a large difference between the drag coefficient obtained by CAE simulation and the actual drag coefficient, resulting in the problem of low accuracy of the obtained drag coefficient. Summary of the invention

[0004] The embodiments of the present invention provide a method, device, electronic device and storage medium for determining the wind resistance coefficient of an automobile, which can effectively improve the accuracy of the obtained wind resistance coefficient.

[0005] A first aspect of an embodiment of the present invention provides a method for determining a drag coefficient of an automobile, the method comprising:

[0006] According to the target size parameter and the windward area correction value of the target vehicle, a target windward area of ​​the target vehicle is obtained, wherein the windward area correction value is determined according to the expected windward area value, and the expected windward area value is obtained by performing normal distribution processing on the windward area in a preset vehicle wind resistance database;

[0007] According to the target passenger compartment parameters of the target vehicle, obtaining the target passenger compartment volume of the target vehicle;

[0008] Obtaining a target air resistance of the target vehicle according to the target passenger compartment data and the air resistance correction value, wherein the air resistance correction value is determined according to an expected air resistance value, and the expected air resistance value is obtained by performing normal distribution processing on the air resistance of each vehicle in the vehicle wind resistance database;

[0009] A target drag coefficient of the target vehicle is obtained according to the target frontal area, the target passenger compartment volume and the target air resistance.

[0010] Optionally, the step of obtaining the windward area correction value includes:

[0011] Performing normal distribution processing on the frontal area in the automobile wind resistance database to obtain the frontal area expected value and the frontal area deviation value;

[0012] The windward area correction value is determined according to an average difference between the windward area in the automobile risk data and the fitted windward area, wherein the fitted windward area is determined according to the expected windward area value and the windward area deviation value.

[0013] Optionally, the step of obtaining the air resistance correction value includes:

[0014] Performing normal distribution processing on the air resistance in the automobile wind resistance database to obtain the expected value of the air resistance and the air resistance deviation value;

[0015] The air resistance correction value is determined according to an average difference between the air resistance in the automobile wind resistance database and the fitted air resistance, wherein the fitted air resistance is determined according to the expected air resistance value and the air resistance deviation value.

[0016] Optionally, the performing normal distribution processing on the air resistance in the automobile wind resistance database to obtain the expected value of the air resistance and the air resistance deviation value includes:

[0017] The volume of the passenger compartment of each car is used to perform normal distribution processing on the air resistance in the car wind resistance database to obtain the expected value of the air resistance and the deviation value of the air resistance.

[0018] Optionally, obtaining a target drag coefficient of the target vehicle according to the target frontal area, the target passenger compartment volume, and the target air resistance includes:

[0019] The target drag coefficient is obtained according to the target frontal area, the target passenger compartment volume, the target air resistance and the drag coefficient correction value, wherein the drag coefficient correction value is determined according to the expected value of the air drag coefficient, and the expected value of the drag coefficient is obtained by performing normal distribution processing on the drag coefficient in the automobile drag database.

[0020] Optionally, the step of obtaining the drag coefficient correction value includes:

[0021] Performing normal distribution processing on the drag coefficient in the automobile drag database to obtain the expected value of the drag coefficient and the deviation value of the drag coefficient;

[0022] The drag coefficient correction value is determined according to an average difference between the drag coefficient in the automobile drag database and the fitted drag coefficient, wherein the fitted drag coefficient is determined according to the expected drag coefficient value and the drag coefficient deviation value.

[0023] A second aspect of an embodiment of the present invention further provides a device for determining a drag coefficient of an automobile, the device comprising:

[0024] a frontal area determination unit, configured to obtain a target frontal area of ​​the target vehicle according to a target size parameter of the target vehicle and a frontal area correction value, wherein the frontal area correction value is determined according to an expected frontal area value, and the expected frontal area value is obtained by performing normal distribution processing on the frontal area in a preset vehicle wind resistance database;

[0025] a passenger compartment volume determination unit, configured to obtain a target passenger compartment volume of the target vehicle according to a target passenger compartment parameter of the target vehicle;

[0026] an air resistance determination unit, configured to obtain a target air resistance of the target vehicle according to the target passenger compartment data and an air resistance correction value, wherein the air resistance correction value is determined according to an expected air resistance value, and the expected air resistance value is obtained by performing normal distribution processing on the air resistance of each vehicle in the vehicle wind resistance database;

[0027] The drag coefficient determination unit is used to obtain a target drag coefficient of the target vehicle according to the target frontal area, the target passenger compartment volume and the target air resistance.

[0028] A third aspect of an embodiment of the present invention also provides an electronic device, comprising a memory and one or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by one or more processors to execute operating instructions corresponding to the method for determining the vehicle drag coefficient as provided in the first aspect.

[0029] A fourth aspect of an embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon, wherein when the program is executed by a processor, the program implements the steps corresponding to the method for determining the automobile drag coefficient provided in the first aspect.

[0030] The above one or at least one technical solution in the embodiments of the present application has at least the following technical effects:

[0031] Based on the above technical scheme, the target frontal area of ​​the target car is obtained according to the target size parameters of the target car and the windward area correction value; the target passenger compartment volume of the target car is obtained according to the target passenger compartment parameters of the target car; the target air resistance of the target car is obtained according to the target passenger compartment data and the air resistance correction value; the target drag coefficient of the target car is obtained according to the target frontal area, the target passenger compartment volume and the target air resistance.

[0032] Since the frontal area correction value is determined based on the expected value of the frontal area, and the expected value of the frontal area is obtained by subjecting the frontal area in the preset automobile wind resistance database to normal distribution processing, the frontal area correction value has a higher matching degree with the actual automobile, and thus the accuracy of the target frontal area determined by the frontal area correction value is higher; the accuracy of the target passenger compartment volume obtained according to the target passenger compartment parameters is higher; and the air resistance correction value is determined based on the expected value of the air resistance, and the expected value of the air resistance is obtained by subjecting the air resistance of each automobile in the automobile wind resistance database to normal distribution processing, so that the air resistance correction value has a higher matching degree with the actual automobile, and thus the accuracy of the target air resistance determined by the air resistance correction value is higher; and on the basis of the higher accuracy of the target frontal area, target passenger compartment volume and target air resistance, the accuracy of the obtained target drag coefficient will also be improved accordingly, and on the basis of the improved accuracy of the obtained target drag coefficient, the efficiency of automobile design can be effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A schematic flow chart of a method for determining a vehicle drag coefficient provided in an embodiment of the present application;

[0034] Figure 2 A schematic diagram of the structure of a device for determining a vehicle drag coefficient provided in an embodiment of the present application. DETAILED DESCRIPTION

[0035] The main implementation principles, specific implementation methods and corresponding beneficial effects of the technical solutions of the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0036] Example

[0037] Please refer to Figure 1 , an embodiment of the present application provides a method for determining a drag coefficient of an automobile, the method comprising:

[0038] S101, obtaining a target windward area of ​​the target vehicle according to a target size parameter and a windward area correction value of the target vehicle, wherein the windward area correction value is determined according to an expected windward area value, and the expected windward area value is obtained by performing normal distribution processing on the windward area in a preset vehicle wind resistance database;

[0039] S102, acquiring a target passenger compartment volume of the target vehicle according to a target passenger compartment parameter of the target vehicle;

[0040] S103, acquiring a target air resistance of the target vehicle according to the target passenger compartment data and the air resistance correction value, wherein the air resistance correction value is determined according to an expected air resistance value, and the expected air resistance value is obtained by performing normal distribution processing on the air resistance of each vehicle in the vehicle wind resistance database;

[0041] S104. Obtain a target drag coefficient of the target vehicle according to the target frontal area, the target passenger compartment volume, and the target air resistance.

[0042] In the embodiments of this specification, the target vehicle may be a fuel vehicle, a hybrid vehicle, an electric vehicle, etc.

[0043] Before step S101, it is necessary to pre-set a car wind resistance database, and then obtain the windward area correction value and the air resistance correction value through the data in the car wind resistance database, and then execute step S101. The car wind resistance database includes parameters such as car model, wind resistance coefficient, windward area, air resistance, car width, car height, wheelbase, front wheel track and rear wheel track, and of course also includes the product of car width and car height, etc., which are not specifically limited in this specification.

[0044] For example, the automobile wind resistance database includes data of model A, model B, model C, model D, model E, model F, model G, model H, model I and model J, as shown in Table 1 below:

[0045]

[0046] Table 1

[0047] The air resistance in Table 1 is the air resistance of the vehicle at a speed of 120 km / h, and m 2 represents square meter, N represents Newton, and mm represents millimeter.

[0048] Before executing step S101, it is necessary to obtain a windward area correction value, and the step of obtaining the windward area correction value includes: performing normal distribution processing on the windward area in the automobile wind resistance database to obtain an expected windward area value and a windward area deviation value; determining the windward area correction value according to the average difference between the windward area in the automobile risk data and the fitted windward area, wherein the fitted windward area is determined based on the expected windward area value and the windward area deviation value.

[0049] Specifically, the vehicle width and height in the vehicle wind resistance database can be used to fit the windward area to determine the fitting coefficient, and after determining the fitting coefficient, the fitting windward area is determined based on the fitting coefficient, the vehicle width and the vehicle height.

[0050] Specifically, the frontal area of ​​the car satisfies the following formula 1, which is:

[0051] A=k a ×w×h Formula 1

[0052] In formula 1, k a is the fitting coefficient, which can be dimensionless; w is the width of the vehicle (i.e., the width of the vehicle), in meters (m); h is the height of the vehicle (i.e., the height of the vehicle), in meters; according to the data in Table 1, the windward area and the fitted windward area of ​​each vehicle model are obtained for least squares calculation, and the fitting coefficient ka=0.84 is obtained. The fitted windward area and fitting coefficient are calculated and shown in Table 2 below.

[0053]

[0054] Table 2

[0055] After determining the fitting coefficient, since the frontal area in the automobile wind resistance database follows the normal distribution N(μ, σ 2 ), so the fitted windward area in Table 2 can be processed and calculated according to the normal distribution, and the expected value of the windward area μ1=2.388m 2 And the windward area deviation value σ1=0.1654m 2 That is, A~N(2.388,0.1654 2 ).

[0056] In this way, the windward area and fitted windward area of ​​each model can be obtained from Table 2. According to the windward area of ​​each model, the mean windward area is determined to be 2.389m 2 ; and according to the fitted frontal area of ​​each vehicle model, the fitted mean is determined to be 2.388m 2According to the windward area mean and the fitted mean, a windward area correction value is determined. The windward area correction value can be the difference between the windward area mean and the fitted mean or the product of the difference between the windward area mean and the fitted mean and the corresponding weight, wherein the weight can be set manually or by the device, or can be set according to actual needs, and the weight can be, for example, 98% and 95%.

[0057] In another embodiment of the present specification, in order to further improve the accuracy of the windward area correction value, the windward area confidence of each vehicle model can be determined according to the fitted windward area and the measured windward area; then the first target vehicle model set whose windward area confidence is not less than the set windward confidence is obtained, wherein the set windward confidence can be set manually or by the device, or can be set according to actual needs, and the set windward confidence can be, for example, 93%, 95%, and 96%, etc.; the windward area correction value is determined according to the measured windward area mean and the fitted mean corresponding to the first target vehicle model set. In this way, by setting the windward confidence and selecting data with high confidence to obtain the windward area correction value, the accuracy of the obtained windward area correction value is also improved.

[0058] For example, taking Table 2 as an example, if the confidence interval of the fitted frontal area with a confidence level of not less than 95% is (2.30, 2.476), the average of the fitted frontal areas of model A, model D, model I and model J is calculated, where the fitted frontal areas of model A, model D, model I and model J are 2.424925684, 2.4592272, 2.31568829 and 2.35407172 respectively (the values ​​in Table 2 are only retained to 2 decimal places), and μ is obtained. 拟合 =2.3885m 2 ; If the confidence interval of the measured windward area with a confidence level of not less than 95% is (2.30, 2.475), then the average of the measured windward areas of model A, model D, model G, model I and model J is calculated. Among them, the measured windward areas of model A, model D, model G, model I and model J are 2.447, 2.363, 2.34, 2.35 and 2.36 respectively, and the average value is 2.372 to obtain μ 实测 =2.372m 2 ; In this way, the windward area correction value μ A修正 =μ 拟合 -μ 实测 =0.0165m 2 .

[0059] And after the frontal area correction value is obtained, step S101 is executed.

[0060] In step S101, target size parameters of the target vehicle may be obtained, the target size parameters including the vehicle width and vehicle height of the target vehicle, and then the target size parameters are input into Formula 1 to obtain the fitted frontal area of ​​the target vehicle, and then the target frontal area is determined based on the fitted frontal area of ​​the target vehicle and the frontal area correction value.

[0061] Specifically, the target windward area can be taken as the difference between the fitted windward area of ​​the target vehicle and the windward area correction value, or the product of the difference between the fitted windward area of ​​the target vehicle and the windward area correction value and the corresponding weight. This specification does not make any specific restrictions.

[0062] Specifically, the calculation formula 2 of the target frontal area A1 is as follows:

[0063] A1=k a ×w×h-μ A修正 Formula 2

[0064] In this way, after obtaining the target size parameters and μ A修正 After that, the obtained target size parameters and μ A修正 Input into Formula 2, the calculated value is the target windward area. Since the windward area correction value is determined based on the expected windward area value, and the expected windward area value is obtained by normal distribution processing of the windward area in the preset automobile wind resistance database, the windward area correction value is more closely matched with the actual automobile, and the target windward area determined by the windward area correction value is more accurate.

[0065] After the target frontal area is obtained, step S102 is executed.

[0066] In step S102, the target passenger compartment parameters may be first obtained, and then the target passenger compartment parameters may be input into the corresponding passenger compartment volume formula to obtain the target passenger compartment volume, wherein the target passenger compartment parameters include parameters such as vehicle height, wheelbase, front track and rear track. At this time, if Q is the target passenger compartment volume, the unit is m 3 , then the target passenger compartment volume is expressed by Formula 3, specifically:

[0067] Q=h×L×(w f +w r ) / 2 Formula 3

[0068] In formula 3, h is the vehicle height; L is the wheelbase, in meters, and w is f is the front wheelbase, in m; w r is the front wheelbase, in m. Thus, after obtaining the target passenger compartment parameters, the target passenger compartment parameters are input into Formula 3 to obtain the target passenger compartment volume.

[0069] After the target passenger compartment volume is obtained, step S103 is executed.

[0070] Furthermore, before executing step S103, it is necessary to obtain an air resistance correction value, and the step of obtaining the air resistance correction value includes: performing normal distribution processing on the air resistance in the automobile wind resistance database to obtain an expected air resistance value and an air resistance deviation value; determining the air resistance correction value according to the average difference between the air resistance in the automobile wind resistance database and the fitted air resistance, wherein the fitted air resistance is determined based on the expected air resistance value and the air resistance deviation value.

[0071] Specifically, when performing normal distribution processing on the air resistance in the automobile wind resistance database, the passenger compartment volume of each automobile can be used to perform normal distribution processing on the air resistance in the automobile wind resistance database to obtain the expected value of air resistance and the deviation value of air resistance.

[0072] Specifically, the air resistance can be fitted by the volume of the passenger compartment. The air resistance F at a set vehicle speed is w The following formula 4 is satisfied, specifically:

[0073] F w =k0×Q Formula 4

[0074] Formula 4, k0 is the air resistance fitting coefficient, unit N / m 3 For example, the least squares method can be used to calculate the frontal area and the fitted frontal area in the automobile wind resistance database, and the fitting coefficient k0 = 90.34 N / m when the vehicle speed is 120 km / h 3 .

[0075] Furthermore, due to the air resistance F w It is a linear combination with the passenger compartment volume. On the basis that the passenger compartment volume conforms to the normal distribution, the air resistance also conforms to the normal distribution. The fitted air resistance in Table 1 is processed with the normal distribution, and the expected value of air resistance μ3 = 583.27N and the deviation value of air resistance σ3 = 43.23N are obtained, as shown in Table 3. That is, F w ~N(583.27,43.23 2 ).

[0076]

[0077] Table 3

[0078] In this way, the measured resistance and fitted wind resistance of each model can be obtained from Table 3, and the average measured resistance is determined to be 581.90N according to the measured resistance of each model; and the average fitted wind resistance is determined to be 583.27N according to the fitted wind resistance of each model. The air resistance correction value is determined according to the average measured resistance and the average fitted wind resistance. The air resistance correction value can be the difference between the average measured resistance and the average fitted wind resistance or the product of the difference between the average measured resistance and the average fitted wind resistance and the corresponding weight, wherein the weight can be set manually or by the device, or can be set according to actual needs. The weight can be, for example, 98% and 95%.

[0079] In another embodiment of the present specification, in order to further improve the accuracy of the air resistance correction value, the resistance confidence of each vehicle model can be determined according to the measured resistance and the fitted wind resistance; then a third target vehicle model set whose resistance confidence is not less than the set resistance confidence is obtained, wherein the set resistance confidence can be set manually or by the device, or can be set according to actual needs, and the set resistance confidence can be, for example, 92%, 95%, and 96%, etc.; the air resistance correction value is determined according to the measured resistance mean value and the fitted wind resistance mean value corresponding to the third target vehicle model set. In this way, the air resistance correction value is obtained by setting the resistance confidence and selecting data with high confidence, so that the accuracy of the obtained air resistance correction value is also improved.

[0080] For example, taking Table 3 as an example, if the confidence interval of the fitted air resistance is not less than 95% is (560.17, 606.38), then the average value of the fitted wind resistance of model A, model C, model D, model G, model I and model J is obtained to obtain μ Fw拟合 =574.32N; if the confidence interval of the measured air resistance is not less than 95% is (544.93, 618.873), then the average value of the measured resistance of model A, model D and model G is obtained to obtain μ Fw实测 =599.67N; In this way, the air resistance correction value μ F修正 =μ F拟合 -μ F实测 =-25.3N.

[0081] And, after the air resistance correction value is obtained, step S103 is executed.

[0082] In step S103, the target air resistance may be obtained based on the target passenger compartment volume obtained in step S102 and the target product of the air resistance fitting coefficient, and then based on the target product and the air resistance correction value.

[0083] Specifically, the target frontal area may be taken as the difference between the target product and the air resistance correction value, or the target frontal area may be taken as the product of the difference between the target product and the air resistance correction value and the corresponding weight, and this specification does not impose any specific limitation.

[0084] Specifically, the target air resistance F w1 The calculation formula 5 is as follows:

[0085] F w1 =k0×Q-μ F修正 Formula 5

[0086] In this way, Q is calculated in step S102, and μ is obtained. F修正 After that, Q is input into Formula 5, and the calculated value is the target air resistance. Since the air resistance correction value is determined according to the expected air resistance value, which is obtained by performing normal distribution processing on the air resistance of each car in the car wind resistance database, the air resistance correction value has a higher matching degree with the actual car, and thus the target air resistance determined by the air resistance correction value has a higher accuracy.

[0087] After the target air resistance is obtained, step S104 is executed.

[0088] In step S104, the target drag coefficient can be obtained according to the target frontal area, the target passenger compartment volume, the target air resistance and the drag coefficient correction value, wherein the drag coefficient correction value is determined according to the expected value of the air drag coefficient, and the expected value of the drag coefficient is obtained by performing normal distribution processing on the drag coefficient in the automobile wind resistance database.

[0089] Before executing step S104, it is necessary to obtain a drag coefficient correction value, and the step of obtaining the drag coefficient correction value includes: performing normal distribution processing on the drag coefficient in the automobile drag database to obtain an expected drag coefficient value and a drag coefficient deviation value; determining the drag coefficient correction value according to an average difference between the drag coefficient in the automobile drag database and the fitted drag coefficient, wherein the fitted drag coefficient is determined according to the expected drag coefficient value and the drag coefficient deviation value.

[0090] Specifically, the air resistance can be determined based on the target frontal area, air resistance coefficient and atmospheric density obtained in step S101. The air resistance F at the vehicle speed V is w The formula 6 is as follows:

[0091]

[0092] In formula 6, ρ is the atmospheric density, which is generally taken as ρ = 1.2258 N·s 2 ·m -4 ; CD is the drag coefficient; A is the frontal area of ​​the vehicle, in m 2 , V represents the vehicle speed, in km / h.

[0093] Thus, by combining Formula 4 and Formula 6, we can get Formula 7, which is:

[0094]

[0095] In this way, after formula 7 is determined, the fitted drag coefficient of the vehicle can be calculated according to formula 7 and the fitted frontal area, the fitted passenger compartment volume and the air resistance fitting coefficient k0.

[0096] After determining the fitted drag coefficient, since the drag coefficient in the automobile risk data also obeys the normal distribution, the fitted drag coefficient can be processed for normal distribution to obtain the expected value μ4 of the drag coefficient and the deviation value σ4 of the drag coefficient. Thus, according to the data in Formula 7, Table 2, Table 3 and Table 4, the fitted drag coefficient of the vehicle is calculated as shown in Table 4 below:

[0097]

[0098] Table 4

[0099] Among them, the fitting drag coefficient can be obtained from Table 4 as fitting C D The data in the column and the measured drag coefficient are the measured C D The data in the column.

[0100] In this way, the measured drag coefficient and the fitted drag coefficient of each vehicle model can be obtained from Table 4, and the average of the measured drag coefficient is determined to be 0.357 according to the measured drag coefficient of each vehicle model; and the average of the fitted drag coefficient is determined to be 0.3588 according to the fitted drag coefficient of each vehicle model. According to the average of the measured drag coefficient and the average of the fitted drag coefficient, the drag coefficient correction value is determined. The drag coefficient correction value can be the difference between the average of the measured drag coefficient and the average of the fitted drag coefficient or the product of the difference between the average of the measured drag coefficient and the average of the fitted drag coefficient and the corresponding weight, wherein the weight can be set manually or by the device, or can be set according to actual needs, and the weight can be, for example, 98% and 95%.

[0101] In another embodiment of the present specification, in order to further improve the accuracy of the drag coefficient correction value, the drag coefficient confidence of each vehicle model can be determined according to the measured drag coefficient and the fitted drag coefficient; then a fourth target vehicle model set whose drag coefficient confidence is not less than the set drag coefficient confidence is obtained, wherein the set drag coefficient confidence can be set manually or by the device, or can be set according to actual needs, and the set drag coefficient confidence can be, for example, 92%, 95%, and 96%, etc.; the drag coefficient correction value is determined according to the measured drag coefficient mean value and the fitted drag coefficient mean value corresponding to the fourth target vehicle model set. In this way, by setting the drag coefficient confidence and selecting data with high confidence to obtain the drag coefficient correction value, the accuracy of the obtained drag coefficient correction value is also improved.

[0102] For example, taking Table 4 as an example, if the confidence interval of the fitted drag coefficient is not less than 95% is (0.3537, 0.3638), then the average value of the fitted drag coefficients of Model C, Model D, Model E, Model F, Model H and Model I is obtained to obtain μ Cd拟合 =0.3605; if the confidence interval of the measured drag coefficient is not less than 95% is (0.3453, 0.3687), then the average value of the measured drag coefficients of model A, model B and model G is obtained to obtain μ Cd实测 =0.3621; In this way, the drag coefficient correction value μ Cd修正 =μ Cd拟合 -μ Cd实测 =-0.0016.

[0103] In this way, the above automobile wind group database establishes the fitting relationship between the windward area and the passenger compartment volume, the fitting relationship between the passenger compartment volume and the air resistance, and the fitting relationship between the passenger compartment volume, the windward area and the drag coefficient. Therefore, the air resistance level and the drag coefficient level of the automobile can be evaluated through the passenger compartment volume data.

[0104] And, after obtaining the drag coefficient correction value, execute step S104.

[0105] In step S103, the target frontal area A1 obtained in step S101, the target passenger compartment volume Q, the air resistance fitting coefficient k0 and the drag coefficient correction value μ obtained in step S102 may be used to calculate the wind speed. Cd修正 , and obtain the target drag coefficient.

[0106] Specifically, the air resistance fitting coefficient can be obtained through step S103. Thus, after obtaining A1, Q, k0 and μ Cd修正 Afterwards, the target drag coefficient can be calculated by inputting it into the corresponding function.

[0107] Specifically, if the target drag coefficient is expressed as C D1Indicates that the corresponding function is Formula 8, which is:

[0108]

[0109] For example, assuming that the design and manufacturing level of a development model matches the data in the above-mentioned car wind group database, the car is 1860mm wide, 1690mm high, with a wheelbase of 2715mm, a front track of 1590mm, and a rear track of 1595mm. Thus, the target drag coefficient of the car can be calculated by the above formula.

[0110] Specifically, first, μ is calculated based on the above-mentioned automobile wind resistance database. A修正 , the width and height of the vehicle are input into Formula 2, and the target frontal area A1 of the vehicle is calculated as:

[0111] A1=k a ×w×h-μ a修正 =0.84×1.86×1.69-0.0165≈2.624m 2

[0112] Then, the vehicle height, wheelbase, front track and rear track of the vehicle are input into Formula 3 to calculate the target passenger compartment volume Q of the vehicle:

[0113]

[0114] Accordingly, Q and μ F修正 Enter this into Formula 5 to estimate the air resistance F of the car at a speed of 120 km / h. w1 for:

[0115] F w1 =k0×Q1-μ F修正 ≈90.34×7.31-(-25.3)≈685.4N

[0116] Since the estimated resistance meets the limiting conditions, that is, F w实测 ~N(581.9,69.189 2 ), then under this size, at a speed of 120km / h, the probability that the air resistance reaches 685.4N is:

[0117]

[0118] Similarly, the target drag coefficient C can be estimated by formula 8: D1 :

[0119]

[0120] Due to C D ~N(0.3570,0.0219 2), then the target drag coefficient C D1 The probability of reaching 0.36543 is:

[0121]

[0122] It can be seen that the probability that the car's drag coefficient is less than 0.37112 is 74.22%, and the target drag coefficient C is determined. D1 The target drag coefficient is 0.36543. Thus, the method provided by this embodiment can obtain a higher accuracy of the target drag coefficient.

[0123] The above one or at least one technical solution in the embodiments of the present application has at least the following technical effects:

[0124] Based on the above technical scheme, the target frontal area of ​​the target car is obtained according to the target size parameters of the target car and the windward area correction value; the target passenger compartment volume of the target car is obtained according to the target passenger compartment parameters of the target car; the target air resistance of the target car is obtained according to the target passenger compartment data and the air resistance correction value; the target drag coefficient of the target car is obtained according to the target frontal area, the target passenger compartment volume and the target air resistance.

[0125] Since the frontal area correction value is determined based on the expected value of the frontal area, and the expected value of the frontal area is obtained by subjecting the frontal area in the preset automobile wind resistance database to normal distribution processing, the frontal area correction value has a higher matching degree with the actual automobile, and thus the accuracy of the target frontal area determined by the frontal area correction value is higher; the accuracy of the target passenger compartment volume obtained according to the target passenger compartment parameters is higher; and the air resistance correction value is determined based on the expected value of the air resistance, and the expected value of the air resistance is obtained by subjecting the air resistance of each automobile in the automobile wind resistance database to normal distribution processing, so that the air resistance correction value has a higher matching degree with the actual automobile, and thus the accuracy of the target air resistance determined by the air resistance correction value is higher; and on the basis of the higher accuracy of the target frontal area, target passenger compartment volume and target air resistance, the accuracy of the obtained target drag coefficient will also be improved accordingly, and on the basis of the improved accuracy of the obtained target drag coefficient, the efficiency of automobile design can be effectively improved.

[0126] A method for determining the drag coefficient of an automobile is provided in accordance with the above embodiment. The present application also provides a device for determining the drag coefficient of an automobile. Figure 2 , the device comprises:

[0127] A frontal area determination unit 201 is used to obtain a target frontal area of ​​a target vehicle according to a target size parameter and a frontal area correction value of the target vehicle, wherein the frontal area correction value is determined according to an expected frontal area value, and the expected frontal area value is obtained by performing normal distribution processing on the frontal area in a preset vehicle wind resistance database;

[0128] A passenger compartment volume determination unit 202, configured to obtain a target passenger compartment volume of the target vehicle according to a target passenger compartment parameter of the target vehicle;

[0129] an air resistance determination unit 203, configured to obtain a target air resistance of the target vehicle according to the target passenger compartment data and an air resistance correction value, wherein the air resistance correction value is determined according to an expected air resistance value, and the expected air resistance value is obtained by performing normal distribution processing on the air resistance of each vehicle in the vehicle wind resistance database;

[0130] The drag coefficient determination unit 204 is used to obtain a target drag coefficient of the target vehicle according to the target frontal area, the target passenger compartment volume and the target air resistance.

[0131] In an optional implementation, it also includes:

[0132] The windward area correction value acquisition unit is used to perform normal distribution processing on the windward area in the automobile wind resistance database to obtain the expected value of the windward area and the windward area deviation value; determine the windward area correction value according to the average difference between the windward area in the automobile risk data and the fitted windward area, wherein the fitted windward area is determined according to the expected value of the windward area and the windward area deviation value.

[0133] In an optional implementation, it also includes:

[0134] The air resistance correction value acquisition unit is used to perform normal distribution processing on the air resistance in the automobile wind resistance database to obtain the expected air resistance value and the air resistance deviation value; and determine the air resistance correction value according to the average difference between the air resistance in the automobile wind resistance database and the fitted air resistance, wherein the fitted air resistance is determined according to the expected air resistance value and the air resistance deviation value.

[0135] In an optional implementation, the air resistance correction value acquisition unit is used to perform normal distribution processing on the air resistance in the automobile wind resistance database using the passenger compartment volume of each automobile to obtain the expected air resistance value and the air resistance deviation value.

[0136] In an optional embodiment, the drag coefficient determination unit 204 is used to obtain the target drag coefficient based on the target frontal area, the target passenger compartment volume, the target air resistance and the drag coefficient correction value, wherein the drag coefficient correction value is determined based on the expected value of the air drag coefficient, and the expected value of the drag coefficient is obtained by performing normal distribution processing on the drag coefficient in the automobile drag database.

[0137] In an optional implementation, it also includes:

[0138] The drag coefficient correction value acquisition unit is used to perform normal distribution processing on the drag coefficient in the automobile drag database to obtain the expected drag coefficient value and the drag coefficient deviation value; determine the drag coefficient correction value according to the average difference between the drag coefficient in the automobile drag database and the fitted drag coefficient, wherein the fitted drag coefficient is determined according to the expected drag coefficient value and the drag coefficient deviation value.

[0139] Regarding the device in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated here.

[0140] A method for determining the drag coefficient of an automobile is provided in accordance with the above-mentioned embodiment. An embodiment of the present application also provides a storage medium. An embodiment of the present application also provides an electronic device, including a memory and one or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by one or more processors to perform operation instructions corresponding to the method for determining the drag coefficient of an automobile.

[0141] In view of the above-mentioned embodiment, a method for determining the drag coefficient of an automobile is provided. The embodiment of the present application also provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the steps corresponding to the method for determining the drag coefficient of an automobile are implemented.

[0142] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed in this disclosure. The specification and examples are to be considered exemplary only, and the true scope and spirit of the present invention are indicated by the following claims.

[0143] It should be understood that the present invention is not limited to the precise structure described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

[0144] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for determining a vehicle drag coefficient, characterized in that: The method comprises: According to the target size parameter and the windward area correction value of the target vehicle, a target windward area of ​​the target vehicle is obtained, wherein the windward area correction value is determined according to the expected windward area value, and the expected windward area value is obtained by performing normal distribution processing on the windward area in a preset vehicle wind resistance database; According to the target passenger compartment parameters of the target vehicle, obtaining the target passenger compartment volume of the target vehicle; Obtaining a target air resistance of the target vehicle according to the target passenger compartment volume and the air resistance correction value, wherein the air resistance correction value is determined according to an expected air resistance value, and the expected air resistance value is obtained by performing normal distribution processing on the air resistance of each vehicle in the vehicle wind resistance database; The target drag coefficient of the target vehicle is obtained according to the target frontal area, the target passenger compartment volume, the target air resistance and the drag coefficient correction value, wherein the drag coefficient correction value is determined according to the expected value of the drag coefficient, and the expected value of the drag coefficient is obtained by performing normal distribution processing on the drag coefficient in the vehicle drag database.

2. The determination method according to claim 1, characterized in that: The step of obtaining the windward area correction value comprises: Performing normal distribution processing on the frontal area in the automobile wind resistance database to obtain the frontal area expected value and the frontal area deviation value; The windward area correction value is determined according to an average difference between the windward area in the automobile wind resistance database and the fitted windward area, wherein the fitted windward area is determined according to the expected windward area value and the windward area deviation value.

3. The determination method according to claim 2, characterized in that: The step of obtaining the air resistance correction value comprises: Performing normal distribution processing on the air resistance in the automobile wind resistance database to obtain the expected value of the air resistance and the air resistance deviation value; The air resistance correction value is determined according to an average difference between the air resistance in the automobile wind resistance database and the fitted air resistance, wherein the fitted air resistance is determined according to the expected air resistance value and the air resistance deviation value.

4. The determination method according to claim 3, characterized in that: The normal distribution processing of the air resistance in the automobile wind resistance database to obtain the expected value of the air resistance and the air resistance deviation value includes: The volume of the passenger compartment of each car is used to perform normal distribution processing on the air resistance in the car wind resistance database to obtain the expected value of the air resistance and the deviation value of the air resistance.

5. The determination method according to claim 4, characterized in that: The step of obtaining the drag coefficient correction value includes: Performing normal distribution processing on the drag coefficient in the automobile drag database to obtain the expected value of the drag coefficient and the deviation value of the drag coefficient; The drag coefficient correction value is determined according to an average difference between the drag coefficient in the automobile drag database and the fitted drag coefficient, wherein the fitted drag coefficient is determined according to the expected drag coefficient value and the drag coefficient deviation value.

6. A device for determining a drag coefficient of an automobile, characterized in that: The device comprises: a frontal area determination unit, configured to obtain a target frontal area of ​​the target vehicle according to a target size parameter of the target vehicle and a frontal area correction value, wherein the frontal area correction value is determined according to an expected frontal area value, and the expected frontal area value is obtained by performing normal distribution processing on the frontal area in a preset vehicle wind resistance database; a passenger compartment volume determination unit, configured to obtain a target passenger compartment volume of the target vehicle according to a target passenger compartment parameter of the target vehicle; an air resistance determination unit, configured to obtain a target air resistance of the target vehicle according to the target passenger compartment volume and an air resistance correction value, wherein the air resistance correction value is determined according to an expected air resistance value, and the expected air resistance value is obtained by performing normal distribution processing on the air resistance of each vehicle in the vehicle wind resistance database; The drag coefficient determination unit is used to obtain the target drag coefficient of the target vehicle according to the target frontal area, the target passenger compartment volume, the target air resistance and the drag coefficient correction value, wherein the drag coefficient correction value is determined according to the expected value of the drag coefficient, and the expected value of the drag coefficient is obtained by performing normal distribution processing on the drag coefficient in the vehicle wind resistance database.

7. The determination device according to claim 6, characterized in that: Also includes: The windward area correction value acquisition unit is used to perform normal distribution processing on the windward area in the automobile wind resistance database to obtain the expected windward area value and the windward area deviation value; determine the windward area correction value according to the average difference between the windward area in the automobile wind resistance database and the fitted windward area, wherein the fitted windward area is determined according to the expected windward area value and the windward area deviation value.

8. An electronic device, characterized in that: The invention comprises a memory and one or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by one or more processors to execute the operation instructions corresponding to the method according to any one of claims 1 to 5 contained in the one or more programs.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps corresponding to the method according to any one of claims 1 to 5 are implemented.

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