阅读说明：本技术 一种获取车辆结构振动噪声的方法及系统 (Method and system for acquiring vibration noise of vehicle structure ) 是由 石磊 赵跃 张宏波 罗淼 王平 吕卿青 于 2020-06-05 设计创作，主要内容包括：本申请公开了一种获取车辆结构振动噪声的方法及系统,所述方法包括：根据车辆的实际运行状态,获取所述车辆的发动机激励；获取所述车辆的振动传递函数和所述车辆的噪声传递函数；根据所述发动机激励与所述振动传递函数获得车辆结构振动；根据所述发动机激励与所述噪声传递函数获得车辆结构噪声；其中,所述车辆结构振动与所述车辆结构噪声用于联合指示所述车辆结构振动噪声。采用本申请的技术方案,在计算车辆结构振动以及计算车辆结构噪声的过程中,考虑了车辆的实际运行状态下的发动机激励,因此,在利用该发动机激励计算车辆结构振动以及计算车辆结构噪声时,能降低计算结构的误差,提高计算结构的准确度。(The application discloses a method and a system for obtaining vibration noise of a vehicle structure, wherein the method comprises the following steps: acquiring engine excitation of a vehicle according to the actual running state of the vehicle; acquiring a vibration transfer function of the vehicle and a noise transfer function of the vehicle; obtaining vehicle structure vibration according to the engine excitation and the vibration transfer function; obtaining vehicle structure noise according to the engine excitation and the noise transfer function; wherein the vehicle structure vibration and the vehicle structure noise are used in conjunction to indicate the vehicle structure vibration noise. By adopting the technical scheme of the application, the engine excitation under the actual running state of the vehicle is considered in the process of calculating the vehicle structure vibration and calculating the vehicle structure noise, so that the error of the calculation structure can be reduced and the accuracy of the calculation structure can be improved when the engine excitation is used for calculating the vehicle structure vibration and calculating the vehicle structure noise.)

1. A method of obtaining vibration noise of a vehicle structure, comprising:

acquiring engine excitation of a vehicle according to the actual running state of the vehicle;

acquiring a vibration transfer function of the vehicle and a noise transfer function of the vehicle;

obtaining vehicle structure vibration according to the engine excitation and the vibration transfer function; obtaining vehicle structure noise according to the engine excitation and the noise transfer function;

wherein the vehicle structure vibration and the vehicle structure noise are used in conjunction to indicate the vehicle structure vibration noise.

2. The method of claim 1, wherein said obtaining engine excitation of said vehicle comprises:

establishing a coordinate system with a powertrain of the vehicle; wherein the X axis of the coordinate system is in the same direction as the crankshaft of the power assembly; the Y axis of the coordinate system is perpendicular to the X axis; the Z axis of the coordinate system and the piston of the power assembly are in the same direction;

and decomposing the excitation generated by the engine into the excitation corresponding to the six degrees of freedom according to the six degrees of freedom indicated by the coordinate system so as to obtain the engine excitation.

3. The method of claim 2, wherein decomposing the excitation produced by the engine into six-degree-of-freedom corresponding excitations comprises:

the excitation in the first direction is indicated by the horizontal force Fx in the X-axis direction, and is calculated by the following formula:

Fx＝0

the excitation in the second direction is indicated by the horizontal force Fy in the Y-axis direction, which is calculated by the following equation:

the excitation in the third direction is indicated by the horizontal force Fz in the Z-axis direction, which is calculated by the following equation:

excitation in the fourth direction is indicated by the torque Tx in the X-axis direction, and is specifically calculated by the following equation:

Tx＝T_gas-T_inertia

excitation in the fifth direction is indicated by the torque Ty in the Y-axis direction, and is specifically calculated by the following equation:

the excitation in the sixth direction is indicated by the torque Tz in the Z-axis direction, and is specifically calculated by the following formula:

wherein i is a current cylinder of the engine, n is a total number of cylinders of the engine, r is a crank length of the crankshaft, l is a connecting rod length, λ is r/l, e is a length of a crankshaft rotation central axis from a piston sliding central axis, k is e/r, d is the piston diameter, ω is a rotation speed of the engine, m is a rotation speed of the engine, and_intis the mass of the piston, m_rotIs the mass of the connecting rod, L_iDistance of the current cylinder from the center of the engine, theta_iCrank angle, M, of the current cylinder_bTo balance the unbalanced mass of the shaft, L_bFor the center of mass of the unbalanced mass of the balance shaft to rotate about the axis of rotation of the balance shaft, L_xiIs the distance, omega, from the unbalanced mass center of the ith balance shaft to the mass center of the engine in the X direction_{bal_i}To balance the rotational speed of the shaft, T_gasCombustion torque, T, developed for a combustion cylinder of the engine_inertiaMoment of inertia formed for the mass of the crank, a_boreIs the acceleration of the piston, n_balTo balance the number of axes, θ_{bal_i}Is the rotation angle of the ith balance shaft.

4. Method according to claim 3, characterized in that the combustion torque T_gasIn particular toCalculated by the following formula:

the moment of inertia T_inertiaSpecifically calculated by the following formula:

wherein, P_gasIs the combustion cylinder pressure, P, of the engine_atmIs a standard atmospheric pressure, L_yiIs the distance from the unbalanced mass center of the ith balance shaft to the mass center of the engine in the Y direction, L_ziThe distance from the unbalanced mass center of the ith balance shaft to the mass center of the engine in the Z direction.

5. Method according to claim 3 or 4, characterized in that the acceleration a of the piston is_boreSpecifically calculated by the following formula:

wherein, a_boreIs the acceleration of the piston.

6. Method according to claim 1, characterized in that said noise transfer function is calculated in particular by the following formula:

wherein, TF_PjJ is the excitation frequency of the engine,is a stand forThe weighted sound pressure level corresponding to the excitation frequency,to weight coefficient, F_jAnd exciting the corresponding engine when the excitation frequency is j.

7. The method of claim 6, wherein the vehicle structure noise is calculated by the formula:

wherein, P_jThe vehicle structure is noisy.

8. Method according to claim 1, characterized in that the vibration transfer function is calculated in particular by the following formula:

wherein the content of the first and second substances,for said vibration transfer function, ACC_jIs the vibration acceleration, j is the excitation frequency of the engine, F_jAnd exciting the corresponding engine when the excitation frequency is j.

9. The method according to claim 8, wherein the vehicle structure vibration is calculated in particular by the formula:

wherein A is_jVibrating the vehicle structure.

10. A system for obtaining vibration noise of a vehicle structure, comprising: an acquisition unit and a processing unit;

the acquisition unit is used for acquiring the engine excitation of the vehicle according to the actual running state of the vehicle; the system is also used for obtaining a vibration transfer function of the vehicle and a noise transfer function of the vehicle;

the processing unit is used for obtaining vehicle structure vibration according to the engine excitation and the vibration transfer function; obtaining vehicle structure noise according to the engine excitation and the noise transfer function;

wherein the vehicle structure vibration and the vehicle structure noise are used in conjunction to indicate the vehicle structure vibration noise.

Technical Field

The present application relates to the field of vehicle noise, and more particularly, to a method and system for obtaining vibration noise of a vehicle structure.

Background

Noise Vibration and Harshness (NVH) of the vehicle is currently one of the concerns.

To control the NVH of the vehicle, first to be controlled are noise inside the vehicle and vibration inside the vehicle. In the case of a fuel-powered automobile, noise in the vehicle interior and vibration in the vehicle interior are greatly affected by excitation of the engine. However, in the prior art, when obtaining noise and vibration inside the vehicle, only the transfer function is considered, and excitation of the engine is not considered.

Therefore, when the excitation of the engine is not taken into consideration, the error of the obtained noise and vibration inside the vehicle will be large.

Disclosure of Invention

In order to solve the technical problem, the application provides a method and a system for obtaining vibration noise of a vehicle structure, so that the error of obtaining the noise inside the vehicle is reduced, and the error of obtaining the vibration inside the vehicle is reduced.

The embodiment of the application discloses the following technical scheme:

in a first aspect, the present application provides a method of obtaining vibration noise of a vehicle structure, comprising: acquiring engine excitation of a vehicle according to the actual running state of the vehicle; acquiring a vibration transfer function of the vehicle and a noise transfer function of the vehicle; obtaining vehicle structure vibration according to the engine excitation and the vibration transfer function; obtaining vehicle structure noise according to the engine excitation and the noise transfer function; wherein the vehicle structure vibration and the vehicle structure noise are used in conjunction to indicate the vehicle structure vibration noise.

Optionally, the obtaining engine excitation of the vehicle comprises:

establishing a coordinate system with a powertrain of the vehicle; wherein the X axis of the coordinate system is in the same direction as the crankshaft of the power assembly; the Y axis of the coordinate system is perpendicular to the X axis; the Z axis of the coordinate system and the piston of the power assembly are in the same direction;

and decomposing the excitation generated by the engine into the excitation corresponding to the six degrees of freedom according to the six degrees of freedom indicated by the coordinate system so as to obtain the engine excitation.

Optionally, decomposing the excitation generated by the engine into six-degree-of-freedom corresponding excitations includes:

the excitation in the first direction is indicated by the horizontal force Fx in the X-axis direction, and is calculated by the following formula:

Fx＝0

the excitation in the second direction is indicated by the horizontal force Fy in the Y-axis direction, which is calculated by the following equation:

the excitation in the third direction is indicated by the horizontal force Fz in the Z-axis direction, which is calculated by the following equation:

excitation in the fourth direction is indicated by the torque Tx in the X-axis direction, and is specifically calculated by the following equation:

Tx＝T_gas-T_inertia

excitation in the fifth direction is indicated by the torque Ty in the Y-axis direction, and is specifically calculated by the following equation:

the excitation in the sixth direction is indicated by the torque Tz in the Z-axis direction, and is specifically calculated by the following formula:

wherein i is a current cylinder of the engine, n is a total number of cylinders of the engine, r is a crank length of the crankshaft, l is a connecting rod length, λ is r/l, e is a length of a crankshaft rotation central axis from a piston sliding central axis, k is e/r, d is the piston diameter, ω is a rotation speed of the engine, m is a rotation speed of the engine, and_intis the mass of the piston, m_rotIs the mass of the connecting rod, L_iDistance of the current cylinder from the center of the engine, theta_iCrank angle of the current cylinder, M_bTo balance the unbalanced mass of the shaft, L_bFor the center of mass of the unbalanced mass of the balance shaft to rotate about the axis of rotation of the balance shaft, L_xiIs the distance, omega, from the center of mass of the unbalanced mass of the ith balance shaft to the center of mass of the engine in the X direction_{bal_i}To balance the rotational speed of the shaft, T_gasCombustion torque, T, formed for the combustion cylinder of said engine_inertiaMoment of inertia formed for the mass of the crank, a_boreIs the acceleration of the piston, n_balTo balance the number of axes, θ_{bal_i}Is the rotation angle of the ith balance shaft.

Alternatively, the combustion torque T_gasSpecifically calculated by the following formula:

the moment of inertia T_inertiaSpecifically calculated by the following formula:

wherein, P_gasIs the combustion cylinder pressure, P, of the engine_atmIs a standard atmospheric pressure, L_yiIs the distance from the unbalanced mass center of the ith balance shaft to the mass center of the engine in the Y direction, L_ziFor the ith balance shaft to be unevenAnd the distance between the mass center of the balance mass and the mass center of the engine in the Z direction is measured.

Optionally, the acceleration a of the piston_boreSpecifically calculated by the following formula:

wherein, a_boreIs the acceleration of the piston.

Optionally, the noise transfer function is specifically calculated by the following formula:

wherein, TF_PjJ is the excitation frequency of the engine,for the weighted sound pressure level corresponding to the excitation frequency,to weight coefficient, F_jAnd exciting the corresponding engine when the excitation frequency is j.

Optionally, the vehicle structure noise is specifically calculated by the following formula:

wherein, P_jThe vehicle structure is noisy.

Optionally, the vibration transfer function is specifically calculated by the following formula:

wherein the content of the first and second substances,for said vibration transfer function, ACC_jIs the vibration acceleration, j is the excitation frequency of the engine, F_jAnd exciting the corresponding engine when the excitation frequency is j.

Optionally, the vehicle structure vibration is specifically calculated by the following formula:

wherein A is_jVibrating the vehicle structure.

In a second aspect, the present application provides a system for obtaining vibration noise of a vehicle structure, comprising: an acquisition unit and a processing unit; the acquisition unit is used for acquiring the engine excitation of the vehicle according to the actual running state of the vehicle; the system is also used for obtaining a vibration transfer function of the vehicle and a noise transfer function of the vehicle; the processing unit is used for obtaining vehicle structure vibration according to the engine excitation and the vibration transfer function; obtaining vehicle structure noise according to the engine excitation and the noise transfer function; wherein the vehicle structure vibration and the vehicle structure noise are used in conjunction to indicate the vehicle structure vibration noise.

According to the technical scheme, the method has the following advantages:

the invention provides a method and a system for acquiring vibration noise of a vehicle structure, wherein the method comprises the following steps: acquiring engine excitation of a vehicle according to the actual running state of the vehicle; obtaining a vibration transfer function of the vehicle and a noise transfer function of the vehicle; obtaining vehicle structure vibration according to the engine excitation and the vibration transfer function; obtaining vehicle structure noise according to the engine excitation and the noise transfer function; wherein the vehicle structure vibration and the vehicle structure noise are used to jointly indicate the vehicle structure vibration noise. By adopting the technical scheme, the engine excitation in the actual running state of the vehicle is considered in the process of calculating the vehicle structure vibration and calculating the vehicle structure noise, so that the error of the calculation structure can be reduced and the accuracy of the calculation structure can be improved when the engine excitation is used for calculating the vehicle structure vibration and calculating the vehicle structure noise.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a flow chart of a method for obtaining vibration noise of a vehicle structure according to an embodiment of the present disclosure;

FIG. 2 is a schematic diagram of a noise criterion provided by an embodiment of the present application;

fig. 3 is a schematic diagram of a system for acquiring vibration noise of a vehicle structure according to an embodiment of the present application.

Detailed Description

For fuel powered vehicles, engine excitation is one of the major sources of vehicle structural vibration and vehicle structural noise. When the vehicle structure vibration and the vehicle structure noise are calculated, whether the engine excitation is accurate or not can reflect the accuracy of the calculation result, that is, the engine excitation which is not obtained according to the actual running state of the vehicle is adopted, so that a great error is brought to the calculation result. In the prior art, engine excitation of the actual running state of the vehicle is not considered, and only a transfer function is adopted to obtain vehicle structure vibration and vehicle structure noise, so that a large error is brought to the result.

In order to solve the above problems, the present application provides a method and system for obtaining vibration noise of a vehicle structure. In the technical scheme of the application, the engine excitation under the actual running state of the vehicle, the vibration transfer function of the vehicle and the noise transfer function of the vehicle are considered at the same time. On the basis, when the vehicle structure vibration and the vehicle structure noise are calculated, the error of the calculation structure can be reduced, and the accuracy of the calculation result is improved.

In order to make the technical solutions of the present application better understood by those skilled in the art, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments that can be derived by a person skilled in the art from the embodiments given in the present application without making any creative effort shall fall within the protection scope of the present application.

The first embodiment is as follows:

the embodiment of the present application provides a method for acquiring vibration noise of a vehicle structure, which is described in detail below with reference to the accompanying drawings for facilitating understanding of those skilled in the art.

Referring to fig. 1, a flowchart of a method for acquiring vibration noise of a vehicle structure according to an embodiment of the present application is shown.

The method for acquiring the vibration noise of the vehicle structure comprises the following steps:

step 101: and acquiring the engine excitation of the vehicle according to the actual running state of the vehicle.

In order to obtain the engine excitation at the actual operating state of the vehicle, a coordinate system can be established with the powertrain of the vehicle. Specifically, the X axis of the coordinate system is in the same direction as the crankshaft of the power assembly; the Y axis of the coordinate system is perpendicular to the X axis; and the Z axis of the coordinate system and the piston of the power assembly are in the same direction.

After the coordinate system is established, decomposing the excitation generated by the engine by using the six degrees of freedom indicated by the coordinate system, specifically decomposing the excitation into the excitation corresponding to the six degrees of freedom, and acquiring the engine excitation.

The process of resolving the excitation generated by the engine is described in detail below.

The excitation generated by the engine is decomposed into six directions, specifically comprising: excitation in a first direction, excitation in a second direction, excitation in a third direction, excitation in a fourth direction, excitation in a fifth direction, and excitation in a sixth direction. Excitation in the first direction, excitation in the second direction, excitation in the third direction, excitation in the fourth direction, excitation in the fifth direction, and excitation in the sixth direction may jointly indicate engine excitation. Specifically, engine excitation is represented by the following equation:

F＝(Fx,Fy,Fz,Tx,Ty,Tz)

where F is the engine excitation, Fx is the excitation in the first direction, Fy is the excitation in the second direction, Fz is the excitation in the third direction, Tx is the excitation in the fourth direction, Ty is the excitation in the fifth direction, and Tz is the excitation in the sixth direction.

For an excitation Fx in a first direction, the excitation Fx in the first direction is indicated by a horizontal force Fx in the X-axis direction, and is calculated by the following formula:

Fx＝0

for the excitation Fy in the second direction, the excitation in the second direction is indicated by the horizontal force Fy in the Y-axis direction, and is specifically calculated by the following formula:

for the third direction excitation Fz, the third direction excitation is indicated by the Z-axis direction horizontal force Fz, and is specifically calculated by the following formula:

for the excitation Tx in the fourth direction, the excitation in the fourth direction is indicated by the torque Tx in the X-axis direction, and is specifically calculated by the following formula:

Tx＝T_gas-T_inertia

for the excitation Ty in the fifth direction, the excitation in the fifth direction is indicated by the torque Ty in the Y-axis direction, and is specifically calculated by the following formula:

for the excitation Tz in the sixth direction, the excitation Tz in the sixth direction is indicated by the torque Tz in the Z-axis direction, and is specifically calculated by the following formula:

in the above calculation formula of the excitation generated by the engine corresponding to the six degrees of freedom, i is the current cylinder of the engine, n is the total number of cylinders of the engine, r is the crank length of the crankshaft, l is the connecting rod length, λ is r/l, e is the length of the crankshaft rotation central axis from the piston sliding central axis, k is e/r, d is the piston diameter, ω is the rotation speed of the engine, m is the rotation speed of the engine_intIs the mass of the piston, m_rotIs the mass of the connecting rod, L_iDistance of the current cylinder from the center of the engine, theta_iCrank angle, M, of the current cylinder_bTo balance the unbalanced mass of the shaft, L_bIs the rotating radius of the unbalanced mass center of the balance shaft around the rotating axis of the balance shaft, L_xiIs the distance, omega, from the unbalanced mass center of the ith balance shaft to the mass center of the engine in the X direction_{bal_i}To balance the rotational speed of the shaft, T_gasCombustion torque, T, developed for a combustion cylinder of the engine_inertiaMoment of inertia formed for the mass of the crank, a_boreIs the acceleration of the piston, n_balTo balance the number of axes, θ_{bal_i}Is the rotation angle of the ith balance shaft.

During the calculation of the excitation Tx in the fourth direction, the combustion torque T_gasThe method is specifically calculated by the following formula:

the moment of inertia T_inertiaSpecifically calculated by the following formula:

wherein, P_gasIs the combustion cylinder pressure, P, of the engine_atmIs a standard atmospheric pressure, L_yiIs the distance from the unbalanced mass center of the ith balance shaft to the mass center of the engine in the Y direction, L_ziThe distance between the mass center of the unbalanced mass of the ith balance shaft and the mass center of the engine in the Z direction is shown.

In addition, in the above calculation process, the acceleration a of the piston is also used_boreAcceleration a of said piston_boreSpecifically calculated by the following formula:

wherein, a_boreIs the acceleration of the piston.

It should be noted that the parameters in all the calculation formulas described above can be obtained according to the actual operating state of the vehicle, the obtaining mode of the parameters is not limited in the present application, and the parameters can be obtained by sensors, and some of the parameters can also be obtained according to the actual specification of the engine.

In the technical scheme of this application, the influence during piston, bent axle and balance shaft etc. in the engine has been considered, therefore, the vehicle structure vibration and the vehicle structure noise that obtain are more accurate.

Furthermore, after obtaining the engine excitation F, it is necessary to perform frequency domain conversion on F to obtain a corresponding result in the frequency domain. Specifically, it can be represented by the following formula:

F_j＝(Fx_j,Fy_j,Fz_j,Tx_j,Ty_j,Tz_j)

wherein, F_jFor the frequency domain result, Fx, corresponding to the frequency j of the engine excitation F_jFy, the frequency domain result for the excitation in the first direction at frequency j_jFz, the frequency domain result corresponding to the excitation of the second direction at frequency j_jAs a third partyThe frequency domain result, Tx, corresponding to the frequency of the directional excitation at frequency j_jThe frequency domain result, Ty, corresponding to the excitation of the fourth direction at frequency j_jTz being the frequency domain result corresponding to the excitation in the fifth direction at frequency j_jIs the frequency domain result corresponding to the excitation in the fifth direction at frequency j.

Step 102: a vibration transfer function of the vehicle and a noise transfer function of the vehicle are obtained.

As a possible embodiment, both the vibration transfer function of the vehicle and the noise transfer function of the vehicle may be obtained in advance through actual experiments, or may be obtained through simulation inverse modeling.

In addition, in order to reduce errors of a calculation structure and improve the accuracy of the calculation structure when calculating the vehicle structure vibration and calculating the vehicle structure noise by using the engine excitation, the influence of a Vehicle Technical Specification (VTS) on the vibration transfer function of the vehicle and the noise transfer function of the vehicle can be considered in combination with the actual running state of the vehicle.

As a possible implementation, the noise transfer function is specifically calculated by the following formula:

wherein, TF_PjJ is the excitation frequency of the engine,for the weighted sound pressure level corresponding to the excitation frequency,to weight coefficient, F_jAnd exciting the corresponding engine when the excitation frequency is j.

The vibration transfer function is specifically calculated by the following formula:

wherein the content of the first and second substances,for said vibration transfer function, ACC_jIs the vibration acceleration, j is the excitation frequency of the engine, F_jAnd exciting the corresponding engine when the excitation frequency is j.

In order to make the vibration transfer function and the noise transfer function meet the preset standard, target values of the vibration transfer function and the noise transfer function need to be set.

The following description will be made in detail by taking an example of setting the target value of the noise transfer function.

In order to facilitate understanding of those skilled in the art, the following description will be made in detail with reference to the above technical solutions, taking an example when the engine is in a full throttle condition.

Referring to fig. 2, a schematic diagram of a noise standard provided in an embodiment of the present application is shown.

Wherein, the abscissa is the engine speed, and the ordinate is the noise standard.

With reference to fig. 2, the target values of the noise transfer function for different frequencies can be obtained from the noise order requirements corresponding to the engine speed specified in the VTS, as shown in table 1 below:

frequency of	Target value
		25	55.1
30	50.8
		35	46.3
40	43.9
		45	40.7
50	38.0
		55	37.5
60	36.6

Wherein, the frequency is the frequency of the engine, and the target value is the target value corresponding to the noise transfer function.

After obtaining the target value of the noise transfer function, the target value of the noise transfer function corresponding to the preset frequency may be adopted as the preset threshold value at the preset frequency according to the target value of the noise transfer function at the unused frequency shown in table 1. And judging whether the noise transfer function meets the standard or not according to the preset threshold.

Step 103: and obtaining the vehicle structure vibration according to the engine excitation and the vibration transfer function.

The vehicle structure vibration is specifically calculated by the following formula:

wherein A is_jVibrating the vehicle structure.

Step 104: and obtaining vehicle structure noise according to the engine excitation and the noise transfer function.

The vehicle structure noise is specifically calculated by the following formula:

wherein, P_jThe vehicle structure is noisy.

It should be noted that, the execution order of step 103 and step 104 is not limited in this application, and the execution order may be that step 103 is executed first and then step 104 is executed, or may be that step 104 is executed first and then step 103 is executed, or step 103 and step 104 may be executed simultaneously.

After obtaining the vehicle structure vibration and the vehicle structure noise, the vehicle structure vibration and the vehicle structure noise may be utilized for jointly indicating the vehicle structure vibration noise.

The vehicle structure vibration is transmitted to the interior of the vehicle through the structure of the vehicle based on the vibration generated by the excitation of the engine; vehicle structure noise is transmitted to the vehicle interior through the structure of the vehicle based on noise generated by engine excitation.

Compared with the prior art, the method for acquiring the vibration noise of the vehicle structure comprises the following steps: acquiring engine excitation of a vehicle according to the actual running state of the vehicle; acquiring a vibration transfer function of the vehicle and a noise transfer function of the vehicle; obtaining vehicle structure vibration according to the engine excitation and the vibration transfer function; obtaining vehicle structure noise according to the engine excitation and the noise transfer function; wherein the vehicle structure vibration and the vehicle structure noise are used to jointly indicate the vehicle structure vibration noise. By adopting the technical scheme of the application, the engine excitation under the actual running state of the vehicle is considered in the process of calculating the vehicle structure vibration and calculating the vehicle structure noise, so that the error of the calculation structure can be reduced and the accuracy of the calculation structure can be improved when the engine excitation is used for calculating the vehicle structure vibration and calculating the vehicle structure noise.

Example two:

the second embodiment of the present application provides a system for acquiring vibration noise of a vehicle structure, which is specifically described below with reference to the accompanying drawings.

Referring to fig. 3, the figure is a schematic diagram of a system for acquiring vibration noise of a vehicle structure according to an embodiment of the present application.

The system for acquiring the vibration noise of the vehicle structure comprises: an acquisition unit 301 and a processing unit 302.

The obtaining unit 301 is configured to obtain engine excitation of a vehicle according to an actual running state of the vehicle; and is also used for obtaining the vibration transfer function of the vehicle and the noise transfer function of the vehicle.

The processing unit 302 is configured to obtain vehicle structure vibration according to the engine excitation and the vibration transfer function; obtaining vehicle structure noise according to the engine excitation and the noise transfer function;

wherein the vehicle structure vibration and the vehicle structure noise are used in conjunction to indicate the vehicle structure vibration noise.

As a possible implementation, the obtaining unit 301 is specifically configured to establish a coordinate system with a powertrain of the vehicle; wherein the X axis of the coordinate system is in the same direction as the crankshaft of the power assembly; the Y axis of the coordinate system is perpendicular to the X axis; the Z axis of the coordinate system and the piston of the power assembly are in the same direction; and decomposing the excitation generated by the engine into the excitation corresponding to the six degrees of freedom according to the six degrees of freedom indicated by the coordinate system so as to obtain the engine excitation.

As a possible implementation manner, the obtaining unit 301 specifically calculates the excitation corresponding to the six degrees of freedom as follows:

the excitation in the first direction is indicated by the horizontal force Fx in the X-axis direction, and is calculated by the following formula:

Fx＝0

the excitation in the second direction is indicated by the horizontal force Fy in the Y-axis direction, which is calculated by the following equation:

the excitation in the third direction is indicated by the horizontal force Fz in the Z-axis direction, which is calculated by the following equation:

excitation in the fourth direction is indicated by the torque Tx in the X-axis direction, and is specifically calculated by the following equation:

Tx＝T_gas-T_inertia

excitation in the fifth direction is indicated by the torque Ty in the Y-axis direction, and is specifically calculated by the following equation:

the excitation in the sixth direction is indicated by the torque Tz in the Z-axis direction, and is specifically calculated by the following formula:

wherein i is a current cylinder of the engine, n is a total number of cylinders of the engine, r is a crank length of the crankshaft, l is a connecting rod length, λ is r/l, e is a length of a crankshaft rotation central axis from a piston sliding central axis, k is e/r, d is the piston diameter, ω is a rotation speed of the engine, m is a rotation speed of the engine, and_intis the mass of the piston, m_rotIs the mass of the connecting rod, L_iDistance of the current cylinder from the center of the engine, theta_iCrank angle of the current cylinder, M_bTo balance the unbalanced mass of the shaft, L_bRadius of rotation of unbalanced mass centroid of balance shaft about axis of rotation of balance shaft，L_xiIs the distance, omega, from the center of mass of the unbalanced mass of the ith balance shaft to the center of mass of the engine in the X direction_{bal_i}To balance the rotational speed of the shaft, T_gasCombustion torque, T, formed for the combustion cylinder of said engine_inertiaMoment of inertia formed for the mass of the crank, a_boreIs the acceleration of the piston, n_balTo balance the number of axes, θ_{bal_i}Is the rotation angle of the ith balance shaft.

As a possible implementation, the obtaining unit 301 specifically calculates the excitation in the fourth direction as follows:

the combustion torque T_gasSpecifically calculated by the following formula:

the moment of inertia T_inertiaSpecifically calculated by the following formula:

wherein, P_gasIs the combustion cylinder pressure, P, of the engine_atmIs a standard atmospheric pressure, L_yiIs the distance from the unbalanced mass center of the ith balance shaft to the mass center of the engine in the Y direction, L_ziThe distance between the mass center of the unbalanced mass of the ith balance shaft and the mass center of the engine in the Z direction is shown.

As a possible implementation, the obtaining unit 301 specifically calculates the acceleration of the piston as follows:

acceleration a of the piston_boreSpecifically calculated by the following formula:

wherein, a_boreIs the acceleration of the piston.

As a possible implementation manner, the obtaining unit 301 is specifically configured to obtain the noise transfer function according to the following formula:

wherein, TF_PjJ is the excitation frequency of the engine,for the weighted sound pressure level corresponding to the excitation frequency,to weight coefficient, F_jAnd exciting the corresponding engine when the excitation frequency is j.

As a possible implementation, the processing unit 302 is specifically configured to obtain the vehicle structure noise according to the following formula:

wherein, P_jThe vehicle structure is noisy.

As a possible implementation manner, the obtaining unit 301 is specifically configured to obtain the vibration transfer function according to the following formula:

wherein the content of the first and second substances,for said vibration transfer function, ACC_jIs the vibration acceleration, j is the excitation frequency of the engine, F_jAnd exciting the corresponding engine when the excitation frequency is j.

As a possible implementation, the processing unit 302 is specifically configured to obtain the vehicle structure vibration according to the following formula:

wherein A is_jVibrating the vehicle structure.

Compared with the prior art, the system for acquiring the vibration noise of the vehicle structure comprises: an acquisition unit and a processing unit; the acquisition unit is used for acquiring the engine excitation of the vehicle according to the actual running state of the vehicle; the system is also used for obtaining a vibration transfer function of the vehicle and a noise transfer function of the vehicle; the processing unit is used for obtaining vehicle structure vibration according to the engine excitation and the vibration transfer function; obtaining vehicle structure noise according to the engine excitation and the noise transfer function; wherein the vehicle structure vibration and the vehicle structure noise are used in conjunction to indicate the vehicle structure vibration noise. By adopting the technical scheme of the application, the engine excitation under the actual running state of the vehicle is considered in the process of calculating the vehicle structure vibration and calculating the vehicle structure noise, so that the error of the calculation structure can be reduced and the accuracy of the calculation structure can be improved when the engine excitation is used for calculating the vehicle structure vibration and calculating the vehicle structure noise.

The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on different points from other embodiments. In particular, system or apparatus embodiments are described in relative simplicity as they are substantially similar to method embodiments, and reference may be made to some descriptions of method embodiments for related areas. The above-described system or apparatus embodiments are merely illustrative, and the units and modules described as separate components may or may not be physically separate. In addition, some or all of the units and modules may be selected according to actual needs to achieve the purpose of the solution of the embodiment. One of ordinary skill in the art can understand and implement the method without inventive effort.

It should be understood that in the present application, "at least one" means one or more, "a plurality" means two or more. "and/or" for describing an association relationship of associated objects, indicates that there may be three relationships, for example, "a and/or B" may indicate: only A, only B and both A and B are present, wherein A and B may be singular or plural. The character "/" generally indicates that the front and back associated objects are in an "or" relationship. "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single item(s) or plural items. For example, at least one (one) of a, b, or c, may represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", wherein a, b, c may be single or plural.

The foregoing is merely a preferred embodiment of the present application and is not intended to limit the present application in any way. Although the present application has been described with reference to the preferred embodiments, it is not intended to limit the present application. Those skilled in the art can make numerous possible variations and modifications to the disclosed solution, or modify equivalent embodiments to equivalent variations, without departing from the scope of the solution, using the methods and techniques disclosed above. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application still fall within the protection scope of the technical solution of the present application without departing from the content of the technical solution of the present application.