CN114065370A - Method and device for determining automobile wind resistance coefficient, electronic equipment and storage medium - Google Patents
Method and device for determining automobile wind resistance coefficient, electronic equipment and storage medium Download PDFInfo
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Abstract
The invention discloses a method for determining a wind resistance coefficient of an automobile, which comprises the steps of obtaining a target windward area of a target automobile according to a target size parameter and a windward area correction value of the target automobile; acquiring a target passenger compartment volume of the target automobile according to the target passenger compartment parameters of the target automobile; acquiring the target air resistance of the target automobile according to the target passenger compartment data and the air resistance correction value; and acquiring a target wind resistance coefficient of the target automobile according to the target windward area, the target passenger cabin volume and the target air resistance. The method and the device for determining the vehicle wind resistance coefficient, the electronic equipment and the storage medium can effectively improve the accuracy of the obtained wind resistance coefficient.
Description
Technical Field
The present invention relates to the field of automotive technologies, and in particular, to a method and an apparatus for determining an automotive wind resistance coefficient, an electronic device, and a storage medium.
Background
With the rapid development of vehicle technology, the field of automobile application is wider and wider, people continuously improve the performance requirements of all aspects of automobiles, the power performance of the automobiles is required to be good, and the automobiles also need to take space, and the wind resistance of the automobiles when running on roads depends on the wind resistance coefficient and the size of the windward area; and the projected area of the automobile in the driving direction basically determines the size sum of the transverse riding size space; the size of the wheel base determines the size of the longitudinal space of the wheel base; the product of the frontal area and the wheelbase in turn determines the amount of passenger cabin space.
In the prior art, in the design and development process of automobiles, due to the consideration of dynamic property and oil consumption performance, there is usually a limit condition for the air resistance at a specified speed to ensure the safety performance of the automobiles, and thus, the relationship between the windage area and the passenger compartment volume needs to be adjusted under the restriction of air resistance, in order to improve the efficiency of automobile design development, after the passenger compartment volume of the automobile is determined, the wind resistance coefficient of the automobile needs to be calculated, so that the designed automobile can meet the air resistance limiting condition, the prior art usually obtains the wind resistance coefficient through CAE simulation, however, as the road conditions, the environmental climate and the overall vehicle posture are complex when the vehicle is running, the wind resistance coefficient obtained by the CAE simulation is greatly different from the actual wind resistance coefficient, so that the accuracy of the obtained wind resistance coefficient is low.
Disclosure of Invention
The embodiment of the invention provides a method and a device for determining an automobile wind resistance coefficient, electronic equipment and a storage medium, which can effectively improve the accuracy of the obtained wind resistance coefficient.
The first aspect of the embodiment of the invention provides a method for determining an automobile wind resistance coefficient, which comprises the following steps:
acquiring a target windward area of a target automobile according to a target size parameter and a windward area correction value of the target automobile, wherein the windward area correction value is determined according to a windward area expected value, and the windward area expected value is obtained by performing normal distribution processing on the windward area in a preset automobile wind resistance database;
acquiring a target passenger compartment volume of the target automobile according to the target passenger compartment parameters of the target automobile;
obtaining a target air resistance of the target automobile according to the target passenger compartment data and an air resistance correction value, wherein the air resistance correction value is determined according to an air resistance expected value, and the air resistance expected value is obtained by performing normal distribution processing on the air resistance of each automobile in the automobile wind resistance database;
and acquiring a target wind resistance coefficient of the target automobile according to the target windward area, the target passenger cabin volume and the target air resistance.
Optionally, the obtaining of the windward area correction value includes:
carrying out normal distribution processing on the windward area in the automobile wind resistance database to obtain the windward area expected value and the windward area deviation value;
and determining the windward area correction value according to the average difference value of the windward area and the fitted windward area in the automobile risk data, wherein the fitted windward area is determined according to the expected windward area value and the deviation value of the windward area.
Optionally, the step of obtaining the air resistance correction value includes:
carrying out normal distribution processing on the air resistance in the automobile wind resistance database to obtain the expected value and the deviation value of the air resistance;
and determining the air resistance correction value according to the average difference value of the air resistance in the automobile wind resistance database and the fitted air resistance, wherein the fitted air resistance is determined according to the air resistance expected value and the air resistance deviation value.
Optionally, the obtaining of the expected value and the deviation value of the air resistance by performing normal distribution processing on the air resistance in the automobile wind resistance database includes:
and performing normal distribution processing on the air resistance in the automobile wind resistance database by using the volume of the passenger compartment of each automobile to obtain the expected air resistance value and the deviation value of the air resistance.
Optionally, the obtaining a target wind resistance coefficient of the target automobile according to the target windward area, the target passenger cabin volume, and the target air resistance includes:
and obtaining the target wind resistance coefficient according to the target windward area, the target passenger compartment volume, the target air resistance and the corrected value of the wind resistance coefficient, wherein the corrected value of the wind resistance coefficient is determined according to an expected value of the wind resistance coefficient, and the expected value of the wind resistance coefficient is obtained by carrying out normal distribution processing on the wind resistance coefficient in the automobile wind resistance database.
Optionally, the step of obtaining the corrected value of the wind resistance coefficient includes:
carrying out normal distribution processing on the wind resistance coefficients in the automobile wind resistance database to obtain the wind resistance coefficient expected value and the wind resistance coefficient deviation value;
and determining the corrected value of the wind resistance coefficient according to the average difference value of the wind resistance coefficient and a fitted wind resistance coefficient in the automobile wind resistance database, wherein the fitted wind resistance coefficient is determined according to the expected value of the wind resistance coefficient and the deviation value of the wind resistance coefficient.
The second aspect of the embodiments of the present invention also provides a device for determining an automobile wind resistance coefficient, where the device includes:
the system comprises a windward area determining unit, a windward area determining unit and a control unit, wherein the windward area determining unit is used for obtaining a target windward area of a target automobile according to a target size parameter and a windward area correction value of the target automobile, the windward area correction value is determined according to a windward area expected value, and the windward area expected value is obtained by carrying out normal distribution processing on the windward area in a preset automobile windage database;
the passenger compartment volume determining unit is used for acquiring the target passenger compartment volume of the target automobile according to the target passenger compartment parameters of the target automobile;
the air resistance determining unit is used for obtaining the target air resistance of the target automobile according to the target passenger compartment data and the air resistance correction value, wherein the air resistance correction value is determined according to an air resistance expected value, and the air resistance expected value is obtained by carrying out normal distribution processing on the air resistance of each automobile in the automobile wind resistance database;
and the wind resistance coefficient determining unit is used for acquiring a target wind resistance coefficient of the target automobile according to the target windward area, the target passenger cabin volume and the target air resistance.
The third aspect of the embodiments of the present invention further provides an electronic device, which includes a memory and one or more programs, where the one or more programs are stored in the memory and configured to be executed by one or more processors, where the one or more programs include an operation instruction for performing the method for determining a wind resistance coefficient of an automobile according to the first aspect.
The fourth aspect of the embodiments of the present invention also provides a computer-readable storage medium, on which a computer program is stored, where the computer program is executed by a processor to implement the steps corresponding to the method for determining a wind resistance coefficient of an automobile according to the first aspect.
The above one or at least one technical solution in the embodiments of the present application has at least the following technical effects:
based on the technical scheme, the target windward area of the target automobile is obtained according to the target size parameter and the windward area correction value of the target automobile; acquiring a target passenger compartment volume of the target automobile according to the target passenger compartment parameters of the target automobile; acquiring the target air resistance of the target automobile according to the target passenger compartment data and the air resistance correction value; and acquiring a target wind resistance coefficient of the target automobile according to the target windward area, the target passenger cabin volume and the target air resistance.
The windward area correction value is determined according to the windward area expected value, and the windward area expected value is obtained by performing normal distribution processing on the windward area in the preset automobile wind resistance database, so that the matching degree of the windward area correction value and an actual automobile is higher, and the accuracy of the target windward area determined by the windward area correction value is higher; according to the target passenger compartment parameters, the accuracy of the obtained target passenger compartment volume is higher; the air resistance correction value is determined according to the air resistance expected value, and the air resistance expected value is obtained by performing normal distribution processing on the air resistance of each automobile in the automobile wind resistance database, so that the matching degree of the air resistance correction value and an actual automobile is higher, and the accuracy of the target air resistance determined through the air resistance correction value is higher; and then on the basis that the accuracy of the target windward area, the target passenger cabin volume and the target air resistance is higher, the accuracy of the obtained target wind resistance coefficient is improved accordingly, and on the basis that the accuracy of the obtained target wind resistance coefficient is improved, the efficiency of automobile design can be effectively improved.
Drawings
Fig. 1 is a schematic flow chart of a method for determining an automobile wind resistance coefficient according to an embodiment of the present application;
fig. 2 is a schematic structural diagram of a device for determining an automobile wind resistance coefficient according to an embodiment of the present application.
Detailed Description
The main implementation principle, the specific implementation mode and the corresponding beneficial effects of the technical scheme of the embodiment of the present application are explained in detail with reference to the accompanying drawings.
Examples
Referring to fig. 1, an embodiment of the present application provides a method for determining a wind resistance coefficient of an automobile, where the method includes:
s101, obtaining a target windward area of a target automobile according to a target size parameter and a windward area correction value of the target automobile, wherein the windward area correction value is determined according to a windward area expected value, and the windward area expected value is obtained by performing normal distribution processing on the windward area in a preset automobile windage database;
s102, acquiring the volume of a target passenger compartment of the target automobile according to the parameters of the target passenger compartment of the target automobile;
s103, obtaining a target air resistance of the target automobile according to the target passenger compartment data and the air resistance correction value, wherein the air resistance correction value is determined according to an air resistance expected value, and the air resistance expected value is obtained by performing normal distribution processing on the air resistance of each automobile in the automobile wind resistance database;
s104, obtaining a target wind resistance coefficient of the target automobile according to the target windward area, the target passenger cabin volume and the target air resistance.
In the embodiment of the present specification, the target vehicle may be a fuel vehicle, a hybrid vehicle, an electric vehicle, or the like.
Before step S101, an automobile wind resistance database needs to be preset, a windward area correction value and an air resistance correction value are obtained according to data in the automobile wind resistance database, and then step S101 is executed. The automobile wind resistance database includes parameters such as automobile type, wind resistance coefficient, windward area, air resistance, automobile width, automobile height, wheel base, front wheel base and rear wheel base, and certainly includes a product of the automobile width and the automobile height, and the description is not limited specifically.
For example, the automobile wind resistance database includes data of a vehicle type a, a vehicle type B, a vehicle type C, a vehicle type D, a vehicle type E, a vehicle type F, a vehicle type G, a vehicle type H, a vehicle type I, and a vehicle type J, which is specifically shown in table 1 below:
TABLE 1
Wherein the air resistance in Table 1 is the air resistance of the vehicle at a speed of 120km/h, and m2In square meters, N in newtons, and mm in millimeters.
Before step S101 is executed, the step of acquiring the windward area correction value to face includes: carrying out normal distribution processing on the windward area in the automobile wind resistance database to obtain a windward area expected value and a windward area deviation value; and determining a corrected value of the windward area according to the average difference value of the windward area and the fitted windward area in the automobile risk data, wherein the fitted windward area is determined according to the expected value of the windward area and the deviation value of the windward area.
Specifically, the windward area may be fitted using the vehicle width and the vehicle height in the vehicle wind resistance database to determine a fitting coefficient, and after determining the fitting coefficient, the fitted windward area may be determined based on the fitting coefficient, the vehicle width, and the vehicle height.
Specifically, the frontal area of the automobile satisfies the following formula 1, specifically:
A＝kaxwxh formula 1
Wherein, in formula 1, kaAs fitting coefficients, dimensionless; w is the width of the whole vehicle (namely the width of the vehicle) and the unit is meter (m); h is the height of the whole vehicle (namely the height of the vehicle), and the unit m; according to the data in table 1, the windward area and the fitting windward area of each vehicle type are obtained and calculated by the least square method, the fitting coefficient ka is 0.84, and the fitting windward area and the fitting coefficient obtained by calculation are specifically shown in table 2 below.
TABLE 2
After the fitting coefficients are determined, the frontal area in the automobile wind resistance database obeys normal distribution N (mu, sigma)2) Thus, the fitting windward area in table 2 can be subjected to normal distribution processing and calculation to obtain the expected value μ of the windward area1＝2.388m2And windward area deviation value sigma1＝0.1654m2. Namely, A to N (2.388, 0.1654)2)。
Thus, the windward area and the fitted windward area of each vehicle type can be obtained from table 2Determining the average value of the windward area to be 2.389m according to the windward area of each vehicle type2(ii) a And determining the fitting mean value to be 2.388m according to the fitting windward area of each vehicle type2And determining a windward area correction value according to the windward area mean value and the fitting mean value, wherein the windward area correction value can be a difference value of the windward area mean value and the fitting mean value or a product of the difference value of the windward area mean value and the fitting mean value and corresponding weight, the weight can be set manually or automatically by equipment, and can also be set according to actual requirements, and the weight can be 98%, 95% and the like.
In another embodiment of the present description, in order to further improve the accuracy of the windward area correction value, the windward area confidence of each vehicle type may be determined according to the fitted windward area and the actually measured windward area; then, a first target vehicle type set with the windward area confidence coefficient not less than the set windward confidence coefficient is obtained, wherein the set windward confidence coefficient can be set manually or by equipment, and can also be set according to actual requirements, and the set windward confidence coefficient can be 93%, 95%, 96% and the like for example; and determining a windward area correction value according to the actually measured windward area mean value and the fitting mean value corresponding to the first target vehicle type set. Therefore, the windward area correction value is obtained by setting the windward confidence coefficient and selecting the data with high confidence coefficient, so that the accuracy of the obtained windward area correction value is improved.
For example, taking table 2 as an example, if the confidence interval that the confidence of the fitted windward area is not less than 95% is (2.30, 2.476), the fitted windward areas of model a, model D, model I, and model J are averaged, where the fitted windward areas of model a, model D, model I, and model J are 2.424925684, 2.4592272, 2.31568829, and 2.35407172 in this order (only 2 bits after the decimal point is retained in the value in table 2), and μ is obtainedFitting＝2.3885m2(ii) a If the confidence interval of the actually measured windward area is not less than 95% (2.30, 2.475), calculating the average value of the actually measured windward areas of the model A, the model D, the model G, the model I and the model J, wherein the actually measured windward areas of the model A, the model D, the model G, the model I and the model J are 2.447, 2.363, 2.34, 2.35 and 2.36 in sequence, and the average value 2.372 is muMeasured in fact＝2.372m2(ii) a Thus, the windward area correction value muCorrection of A＝μFitting-μMeasured in fact＝0.0165m2。
And executing step S101 after the windward area correction value is acquired.
In step S101, target size parameters of the target vehicle may be obtained, where the target size parameters include a vehicle width and a vehicle height of the target vehicle, and then the target size parameters are input into formula 1 to obtain a fitted windward area of the target vehicle, and then the target windward area is determined according to the fitted windward area of the target vehicle and a corrected value of the windward area.
Specifically, the difference between the fitted windward area of the target vehicle and the windward area correction value may be used as the target windward area, and the product of the difference between the fitted windward area of the target vehicle and the windward area correction value and the corresponding weight may also be used as the target windward area, which is not limited in this specification.
Specifically, the target frontal area A1The calculation formula 2 is as follows:
A1＝ka×w×h-μcorrection of AEquation 2
Thus, the target size parameter and μ of the target automobile are obtainedCorrection of AThen, the obtained target size parameter and muCorrection of AAnd inputting the data into a formula 2, wherein the calculated value is the target windward area. The windward area correction value is determined according to the windward area expected value, and the windward area expected value is obtained by performing normal distribution processing on the windward area in the preset automobile wind resistance database, so that the matching degree of the windward area correction value and an actual automobile is higher, and the accuracy of the target windward area determined through the windward area correction value is higher.
After the target windward area is acquired, step S102 is executed.
In step S102, a target passenger compartment parameter may be obtained first, and then the target passenger compartment parameter is input into a corresponding passenger compartment volume formula, so as to obtain a target passenger compartment volume, where the target passenger compartment parameter includes a vehicle height and an axisDistance, front track and rear track, if Q is the target passenger compartment volume, in m3Then, the target passenger compartment volume is expressed by equation 3, specifically:
Q＝h×L×(wf+wr) Equation 2 formula 3
In the formula 3, h is the vehicle height; l is the wheelbase in m, wfIs the front track, and the unit is m; w is arIs the front track width and has the unit of m. In this manner, after the target passenger compartment parameters are obtained, the target passenger compartment parameters are entered into equation 3 and the target passenger compartment volume is obtained.
After the target passenger compartment volume is acquired, step S103 is executed.
And before executing step S103, acquiring an air resistance correction value, wherein the acquiring of the air resistance correction value includes: carrying out normal distribution processing on the air resistance in the automobile wind resistance database to obtain an air resistance expected value and an air resistance deviation value; and determining an air resistance correction value according to the average difference value of the air resistance in the automobile wind resistance database and the fitting air resistance, wherein the fitting air resistance is determined according to the air resistance expected value and the air resistance deviation value.
Specifically, when the air resistance in the automobile wind resistance database is subjected to the normal distribution processing, the air resistance in the automobile wind resistance database may be subjected to the normal distribution processing by using the passenger compartment volume of each automobile, so as to obtain the expected air resistance value and the deviation air resistance value.
Specifically, the air resistance F at a set vehicle speed may be fitted by the passenger compartment volumewThe following formula 4 is satisfied, specifically:
Fw＝k0XQ formula 4
Equation 4, k0Fitting coefficients for air resistance in units Nm 3For example, the windward area and the fitted windward area in the automobile wind resistance database can be calculated by the least square method to obtain the fitting coefficient k when the automobile speed is 120km/h0＝90.34N/m3。
Further, in the present invention,due to air resistance FwAnd the air resistance value and the volume of the passenger compartment belong to linear combination, on the basis that the volume of the passenger compartment conforms to the normal distribution, the air resistance also obeys the normal distribution, the fitted air resistance in the table 1 is subjected to normal distribution processing, and the expected value mu of the air resistance is obtained3583.27N and air resistance deviation value σ343.23N, as shown in table 3 below. I.e., Fw～N(583.27，43.232)。
TABLE 3
Thus, the measured resistance and the fitted wind resistance of each vehicle type can be obtained from table 3, and the mean value of the measured resistance is determined to be 581.90N according to the measured resistance of each vehicle type; and determining a fitting wind resistance mean value to be 583.27N according to the fitting wind resistance of each vehicle type, and determining an air resistance correction value according to the actual measurement wind resistance mean value and the fitting wind resistance mean value, wherein the air resistance correction value can be a difference value of the actual measurement wind resistance mean value and the fitting wind resistance mean value or a product of the difference value of the actual measurement wind resistance mean value and the fitting wind resistance mean value and corresponding weight, the weight can be set manually or automatically by equipment, and can also be set according to actual requirements, and the weight can be 98% or 95%, and the like.
In another embodiment of the present description, in order to further improve the accuracy of the air resistance correction value, the resistance confidence of each vehicle type may be determined according to the measured resistance and the fitted wind resistance; acquiring a third target vehicle type set with the resistance confidence coefficient not less than the set resistance confidence coefficient, wherein the set resistance confidence coefficient can be set manually or by equipment, and can also be set according to actual requirements, and the set resistance confidence coefficient can be 92%, 95%, 96% and the like, for example; and determining an air resistance correction value according to the actual measurement resistance mean value and the fitting wind resistance mean value corresponding to the third target vehicle type set. Therefore, the air resistance correction value is obtained by setting the resistance confidence coefficient and selecting the data with high confidence coefficient, so that the accuracy of the obtained air resistance correction value is improved.
For example, withTable 3 shows an example, if the confidence interval of the fitting air resistance confidence coefficient is not less than 95% (560.17, 606.38), the fitting windage of model a, model C, model D, model G, model I, and model J is averaged to obtain μFw fitting574.32N; if the confidence interval of the actually measured air resistance is not less than 95 percent is (544.93, 618.873), the actually measured resistances of the vehicle type A, the vehicle type D and the vehicle type G are averaged to obtain muMeasured Fw599.67N; thus, the air resistance correction value muF correction＝μF fitting-μF actual measurement＝-25.3N。
And executing step S103 after the air resistance correction value is acquired.
In step S103, a target air resistance may be obtained according to the target product of the target passenger compartment volume and the air resistance fitting coefficient obtained in step S102, and then according to the target product and the air resistance correction value.
Specifically, the difference between the target product and the air resistance correction value may be used as the target windward area, and the product of the difference between the target product and the air resistance correction value and the corresponding weight may be used as the target windward area.
Specifically, the target air resistance Fw1The calculation formula 5 is as follows:
Fw1＝k0×Q-μf correctionEquation 5
Thus, Q is calculated in step S102, and μ is acquiredF correctionAnd then, putting Q into a formula 5, wherein the calculated value is the target air resistance. The air resistance correction value is determined according to the air resistance expected value, and the air resistance expected value is obtained by performing normal distribution processing on the air resistance of each automobile in the automobile wind resistance database, so that the matching degree of the air resistance correction value and an actual automobile is higher, and the accuracy of the target air resistance determined through the air resistance correction value is higher.
After the target air resistance is acquired, step S104 is executed.
In step S104, a target wind resistance coefficient may be obtained according to the target windward area, the target passenger cabin volume, the target air resistance, and a wind resistance coefficient correction value, where the wind resistance coefficient correction value is determined according to an air resistance coefficient expected value, and the wind resistance coefficient expected value is obtained by performing normal distribution processing on the wind resistance coefficient in the automobile wind resistance database.
Before step S104 is executed, the step of obtaining the windage coefficient correction value includes: carrying out normal distribution processing on the wind resistance coefficients in the automobile wind resistance database to obtain wind resistance coefficient expected values and wind resistance coefficient deviation values; and determining a corrected value of the wind resistance coefficient according to the average difference value of the wind resistance coefficient and a fitted wind resistance coefficient in the automobile wind resistance database, wherein the fitted wind resistance coefficient is determined according to the expected value of the wind resistance coefficient and the deviation value of the wind resistance coefficient.
Specifically, the air resistance F at the vehicle speed V can be determined from the target windward area, the air resistance coefficient, and the atmospheric density acquired in step S101wIs the following formula 6, specifically:
in equation 6, ρ is the atmospheric density, and is generally taken to be 1.2258N · s2·m-4；CDIs the wind resistance coefficient; a is the frontal area of the vehicle in m2And V represents the vehicle speed in km/h.
Thus, equation 4 and equation 6 are combined to obtain equation 7, which is specifically:
thus, after determining equation 7, the fitted passenger cabin volume and the air resistance fitting coefficient k may be determined according to equation 7 and the fitted frontal area, the fitted passenger cabin volume, and the air resistance fitting coefficient k0And calculating the fitting wind resistance coefficient of the vehicle.
After the fitted windage coefficient is determined, the windage coefficient in the vehicle risk data also follows normalAnd (4) performing normal distribution treatment on the fitted wind resistance coefficient to obtain a wind resistance coefficient expected value mu4And the windage resistance coefficient deviation value sigma4Thus, according to the data in equation 7, table 2, table 3 and table 4, the fitting wind resistance coefficient of the vehicle is calculated as shown in table 4 below:
TABLE 4
Wherein, the fitting wind resistance coefficient can be obtained from the table 4 as fitting CDThe data in the column and the measured wind resistance coefficient are measured CDThe data in the column.
Thus, the actually measured wind resistance coefficient and the fitted wind resistance coefficient of each vehicle type can be obtained from table 4, and the average value of the actually measured wind resistance coefficients is determined to be 0.357 according to the actually measured wind resistance coefficient of each vehicle type; and determining a mean value of fitted wind resistance coefficients to be 0.3588 according to the fitted wind resistance coefficient of each vehicle type, and determining a corrected value of the wind resistance coefficients according to the mean value of the actually measured wind resistance coefficients and the mean value of the fitted wind resistance coefficients, wherein the corrected value of the wind resistance coefficients can be the difference value of the mean value of the actually measured wind resistance coefficients and the mean value of the fitted wind resistance coefficients or the product of the difference value of the mean value of the actually measured wind resistance coefficients and the mean value of the fitted wind resistance coefficients and corresponding weights, wherein the weights can be set manually or automatically by equipment, and can also be set according to actual requirements, and the weights can be 98% and 95%, and the like.
In another embodiment of the present description, in order to further improve the accuracy of the corrected value of the wind resistance coefficient, the confidence of the wind resistance coefficient of each vehicle type may be determined according to the actually measured wind resistance coefficient and the fitted wind resistance coefficient; acquiring a fourth target vehicle type set with the wind resistance coefficient confidence coefficient not less than the set wind resistance coefficient confidence coefficient, wherein the set wind resistance coefficient confidence coefficient can be set manually or by equipment, and can also be set according to actual requirements, and the set wind resistance coefficient confidence coefficient can be 92%, 95%, 96% and the like, for example; and determining a wind resistance coefficient correction value according to the actually measured wind resistance coefficient mean value and the fitted wind resistance coefficient mean value corresponding to the fourth target vehicle type set. Therefore, the wind resistance coefficient correction value is obtained by setting the confidence coefficient of the wind resistance coefficient and selecting the data with high confidence coefficient, so that the accuracy of the obtained wind resistance coefficient correction value is improved.
For example, taking table 4 as an example, if the confidence interval of the fitted windage coefficient confidence of not less than 95% is (0.3537, 0.3638), the fitted windage coefficients of model C, model D, model E, model F, model H, and model I are averaged to obtain μCd fitting0.3605; if the confidence interval of the actually measured wind resistance coefficient is not less than 95 percent is (0.3453, 0.3687), the actually measured wind resistance coefficients of the vehicle type A, the vehicle type B and the vehicle type G are averaged to obtain muActual measurement of Cd0.3621; thus, the windage coefficient correction value muCd correction＝μCd fitting-μActual measurement of Cd＝-0.0016。
Therefore, the automobile wind group database establishes a fitting relation between the windward area and the volume of the passenger compartment, a fitting relation between the volume of the passenger compartment and the air resistance, and a fitting relation between the volume of the passenger compartment, the windward area and the wind resistance coefficient. Thus, the air resistance level and the drag coefficient level of the automobile can be evaluated by the passenger compartment volume data.
And executing step S104 after acquiring the windage coefficient correction value.
In step S103, the target frontal area a obtained in step S101 may be used1The target passenger compartment volume Q and the air resistance fitting coefficient k obtained in step S1020And corrected value mu of wind resistance coefficientCd correctionAnd obtaining the target wind resistance coefficient.
Specifically, the air resistance fitting coefficient may be acquired through step S103, and thus, a is acquired1、Q、k0And muCd correctionAnd then, the target wind resistance coefficient can be obtained through calculation by inputting the target wind resistance coefficient into a corresponding function.
Specifically, if the target wind resistance coefficient is CD1Expressed, the corresponding function is formula 8, specifically:
for example, assume that a certain development vehicle model design and manufacturing level matches the data of the vehicle wind array database described above. The width 1860mm of this car, height 1690mm, wheel base 2715mm, front track 1590mm, rear track 1595mm, like this, can calculate the target windage resistance coefficient of this car through the above-mentioned formula.
Specifically, first, μ is calculated from the automobile wind resistance databaseCorrection of AInputting the vehicle width and the vehicle height of the vehicle into a formula 2, and calculating the target windward area A of the vehicle1Comprises the following steps:
A1＝ka×w×h-μa correction＝0.84×1.86×1.69-0.0165≈2.624m2
Then, the height, the wheelbase, the front wheel track and the rear wheel track of the vehicle are input into the formula 3, and the target passenger compartment volume Q of the vehicle is calculated as follows:
accordingly, Q and μF correctionInputting the data into a formula 5, and estimating the air resistance F of the vehicle at the speed of 120km/hw1Comprises the following steps:
Fw1＝k0×Q1-μf correction≈90.34×7.31-(-25.3)≈685.4N
Since the predicted resistance meets the defined condition, i.e. FMeasured of w～N(581.9，69.1892) Then, at this size, at a vehicle speed of 120km/h, the probability that the air resistance reaches 685.4N is:
similarly, the target wind resistance coefficient C can be estimated from equation 8D1：
Due to CD～N(0.3570，0.02192) Then the target wind resistance coefficient CD1The probability of achieving 0.36543 is:
therefore, the possibility that the vehicle wind resistance coefficient is less than 0.37112 is 74.22%, and the target wind resistance coefficient C is determinedD1Is 0.36543. Thus, the accuracy of the obtained target wind resistance coefficient can be higher through the method provided by the embodiment.
The above one or at least one technical solution in the embodiments of the present application has at least the following technical effects:
based on the technical scheme, the target windward area of the target automobile is obtained according to the target size parameter and the windward area correction value of the target automobile; acquiring a target passenger compartment volume of the target automobile according to the target passenger compartment parameters of the target automobile; acquiring the target air resistance of the target automobile according to the target passenger compartment data and the air resistance correction value; and acquiring a target wind resistance coefficient of the target automobile according to the target windward area, the target passenger cabin volume and the target air resistance.
The windward area correction value is determined according to the windward area expected value, and the windward area expected value is obtained by performing normal distribution processing on the windward area in the preset automobile wind resistance database, so that the matching degree of the windward area correction value and an actual automobile is higher, and the accuracy of the target windward area determined by the windward area correction value is higher; according to the target passenger compartment parameters, the accuracy of the obtained target passenger compartment volume is higher; the air resistance correction value is determined according to the air resistance expected value, and the air resistance expected value is obtained by performing normal distribution processing on the air resistance of each automobile in the automobile wind resistance database, so that the matching degree of the air resistance correction value and an actual automobile is higher, and the accuracy of the target air resistance determined through the air resistance correction value is higher; and then on the basis that the accuracy of the target windward area, the target passenger cabin volume and the target air resistance is higher, the accuracy of the obtained target wind resistance coefficient is improved accordingly, and on the basis that the accuracy of the obtained target wind resistance coefficient is improved, the efficiency of automobile design can be effectively improved
To the above embodiment, a method for determining an automobile wind resistance coefficient is provided, and an apparatus for determining an automobile wind resistance coefficient is also provided in the embodiment of the present application, please refer to fig. 2, where the apparatus includes:
a windward area determining unit 201, configured to obtain a target windward area of a target automobile according to a target size parameter and a windward area correction value of the target automobile, where the windward area correction value is determined according to a windward area expected value, and the windward area expected value is obtained by performing normal distribution processing on a windward area in a preset automobile windage database;
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;
an air resistance determining unit 203, configured to obtain a target air resistance of the target automobile according to the target passenger compartment data and an air resistance correction value, where the air resistance correction value is determined according to an air resistance expected value, and the air resistance expected value is obtained by performing normal distribution processing on the air resistance of each automobile in the automobile wind resistance database;
and a wind resistance coefficient determining unit 204, configured to obtain a target wind resistance coefficient of the target automobile according to the target windward area, the target passenger cabin volume, and the target air resistance.
In an optional embodiment, the method further comprises:
the windward area correction value acquisition unit is used for carrying out normal distribution processing on the windward area in the automobile wind resistance database to obtain the windward area expected value and the windward area deviation value; and determining the windward area correction value according to the average difference value of the windward area and the fitted windward area in the automobile risk data, wherein the fitted windward area is determined according to the expected windward area value and the deviation value of the windward area.
In an optional embodiment, the method further comprises:
the air resistance correction value acquisition unit is used for carrying out normal distribution processing on the air resistance in the automobile wind resistance database to obtain the air resistance expected value and the air resistance deviation value; and determining the air resistance correction value according to the average difference value of the air resistance in the automobile wind resistance database and the fitted air resistance, wherein the fitted air resistance is determined according to the air resistance expected value and the air resistance deviation value.
In an alternative embodiment, the air resistance correction value obtaining unit is configured to perform normal distribution processing on the air resistance in the automobile wind resistance database by using the passenger compartment volume of each automobile, so as to obtain the expected air resistance value and the deviation value of the air resistance.
In an alternative embodiment, the wind resistance coefficient determining unit 204 is configured to obtain the target wind resistance coefficient according to the target windward area, the target passenger cabin volume, the target air resistance, and a wind resistance coefficient correction value, where the wind resistance coefficient correction value is determined according to an air resistance coefficient expected value, and the wind resistance coefficient expected value is obtained by performing normal distribution processing on the wind resistance coefficient in the automobile wind resistance database.
In an optional embodiment, the method further comprises:
the wind resistance coefficient correction value acquisition unit is used for carrying out normal distribution processing on the wind resistance coefficients in the automobile wind resistance database to obtain the wind resistance coefficient expected value and the wind resistance coefficient deviation value; and determining the corrected value of the wind resistance coefficient according to the average difference value of the wind resistance coefficient and a fitted wind resistance coefficient in the automobile wind resistance database, wherein the fitted wind resistance coefficient is determined according to the expected value of the wind resistance coefficient and the deviation value of the wind resistance coefficient.
With regard to the apparatus in the above-described embodiment, the specific manner in which each module performs the operation has been described in detail in the embodiment related to the method, and will not be elaborated here.
The embodiment of the present application also provides an electronic device, which includes a memory and one or more programs, where one or more of the programs are stored in the memory and configured to be executed by one or more processors, where the one or more programs include an operation instruction for performing, for example, a method for determining a wind resistance coefficient of an automobile.
The embodiment of the present application also correspondingly provides a computer readable storage medium, on which a computer program is stored, where the computer program, when executed by a processor, implements the steps corresponding to the determination method for the automobile wind resistance coefficient.
Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.
It will be understood that the invention is not limited to the precise arrangements 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 invention is only limited by the appended claims
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (10)
1. A method for determining a wind resistance coefficient of an automobile, the method comprising:
acquiring a target windward area of a target automobile according to a target size parameter and a windward area correction value of the target automobile, wherein the windward area correction value is determined according to a windward area expected value, and the windward area expected value is obtained by performing normal distribution processing on the windward area in a preset automobile wind resistance database;
acquiring a target passenger compartment volume of the target automobile according to the target passenger compartment parameters of the target automobile;
obtaining a target air resistance of the target automobile according to the target passenger compartment data and an air resistance correction value, wherein the air resistance correction value is determined according to an air resistance expected value, and the air resistance expected value is obtained by performing normal distribution processing on the air resistance of each automobile in the automobile wind resistance database;
and acquiring a target wind resistance coefficient of the target automobile according to the target windward area, the target passenger cabin volume and the target air resistance.
2. The method of determining according to claim 1, wherein the step of obtaining the windward area correction value comprises:
carrying out normal distribution processing on the windward area in the automobile wind resistance database to obtain the windward area expected value and the windward area deviation value;
and determining the windward area correction value according to the average difference value of the windward area and the fitted windward area in the automobile risk data, wherein the fitted windward area is determined according to the expected windward area value and the deviation value of the windward area.
3. The determination method according to claim 2, wherein the air resistance correction value obtaining step includes:
carrying out normal distribution processing on the air resistance in the automobile wind resistance database to obtain the expected value and the deviation value of the air resistance;
and determining the air resistance correction value according to the average difference value of the air resistance in the automobile wind resistance database and the fitted air resistance, wherein the fitted air resistance is determined according to the air resistance expected value and the air resistance deviation value.
4. The method of claim 3, wherein the normally distributing the air resistance in the car wind resistance database to obtain the expected air resistance value and the deviation air resistance value comprises:
and performing normal distribution processing on the air resistance in the automobile wind resistance database by using the volume of the passenger compartment of each automobile to obtain the expected air resistance value and the deviation value of the air resistance.
5. The method of claim 4, wherein said obtaining a target wind resistance coefficient for the target vehicle based on the target frontal area, the target passenger cabin volume, and the target air resistance comprises:
and obtaining the target wind resistance coefficient according to the target windward area, the target passenger compartment volume, the target air resistance and the corrected value of the wind resistance coefficient, wherein the corrected value of the wind resistance coefficient is determined according to an expected value of the wind resistance coefficient, and the expected value of the wind resistance coefficient is obtained by carrying out normal distribution processing on the wind resistance coefficient in the automobile wind resistance database.
6. The method of claim 5, wherein said step of obtaining a windage correction value comprises:
carrying out normal distribution processing on the wind resistance coefficients in the automobile wind resistance database to obtain the wind resistance coefficient expected value and the wind resistance coefficient deviation value;
and determining the corrected value of the wind resistance coefficient according to the average difference value of the wind resistance coefficient and a fitted wind resistance coefficient in the automobile wind resistance database, wherein the fitted wind resistance coefficient is determined according to the expected value of the wind resistance coefficient and the deviation value of the wind resistance coefficient.
7. An apparatus for determining a wind resistance coefficient of an automobile, the apparatus comprising:
the system comprises a windward area determining unit, a windward area determining unit and a control unit, wherein the windward area determining unit is used for obtaining a target windward area of a target automobile according to a target size parameter and a windward area correction value of the target automobile, the windward area correction value is determined according to a windward area expected value, and the windward area expected value is obtained by carrying out normal distribution processing on the windward area in a preset automobile windage database;
the passenger compartment volume determining unit is used for acquiring the target passenger compartment volume of the target automobile according to the target passenger compartment parameters of the target automobile;
the air resistance determining unit is used for obtaining the target air resistance of the target automobile according to the target passenger compartment data and the air resistance correction value, wherein the air resistance correction value is determined according to an air resistance expected value, and the air resistance expected value is obtained by carrying out normal distribution processing on the air resistance of each automobile in the automobile wind resistance database;
and the wind resistance coefficient determining unit is used for acquiring a target wind resistance coefficient of the target automobile according to the target windward area, the target passenger cabin volume and the target air resistance.
8. The determination apparatus of claim 7, further comprising:
the windward area correction value acquisition unit is used for carrying out normal distribution processing on the windward area in the automobile wind resistance database to obtain the windward area expected value and the windward area deviation value; and determining the windward area correction value according to the average difference value of the windward area and the fitted windward area in the automobile risk data, wherein the fitted windward area is determined according to the expected windward area value and the deviation value of the windward area.
9. An electronic device comprising a memory and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by one or more processors to execute operating instructions included in the one or more programs for performing the corresponding method according to any one of claims 1 to 7.
10. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the steps corresponding to the method according to any one of claims 1 to 7.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115063474A (en) * | 2022-06-15 | 2022-09-16 | 新疆大学 | Tree windward area calculation method and system |
| CN116227042A (en) * | 2023-05-08 | 2023-06-06 | 中汽研（天津）汽车工程研究院有限公司 | Vehicle windage coefficient determination method, apparatus and storage medium |
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2021
- 2021-09-28 CN CN202111144225.0A patent/CN114065370A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115063474A (en) * | 2022-06-15 | 2022-09-16 | 新疆大学 | Tree windward area calculation method and system |
| CN115063474B (en) * | 2022-06-15 | 2024-03-05 | 新疆大学 | Tree windward area calculation method and system |
| CN116227042A (en) * | 2023-05-08 | 2023-06-06 | 中汽研（天津）汽车工程研究院有限公司 | Vehicle windage coefficient determination method, apparatus and storage medium |
| CN116227042B (en) * | 2023-05-08 | 2023-07-07 | 中汽研（天津）汽车工程研究院有限公司 | Vehicle windage coefficient determination method, apparatus and storage medium |
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