Vehicle driving resistance measurement method and device, computer device, medium and product

Abstract

The application relates to a vehicle driving resistance measuring method and device, computer equipment, a storage medium and a computer program product, which determine the value of aerodynamic resistance by measuring data when a target vehicle is in a coasting test, bring the value into a vehicle driving resistance expression, obtain a target vehicle driving resistance expression, solve the value of the second mechanical resistance in the vehicle mechanical resistance expression based on the value of the wheel edge torque under the condition that the transmission loss and the drive axle loss are removed, solve the value of the target slope based on the value of the second mechanical resistance and the target vehicle driving resistance expression under the condition that the transmission loss and the drive axle loss are not removed, and bring the value of the target slope into the vehicle driving resistance expression and the vehicle mechanical resistance expression, so that the values of the corresponding vehicle wind resistance coefficient and the vehicle rolling resistance coefficient can be accurately obtained, and the value of the vehicle driving resistance with higher precision is obtained.

Description

Technical Field

[0001] This application relates to the technical field of commercial vehicles, and in particular to a method, device, computer equipment, storage medium, and computer program product for measuring the driving resistance of a vehicle. Background Technology

[0002] Economic performance is one of the most important performance indicators in the development of heavy commercial vehicles. Currently, the main methods used to evaluate the economic performance of a vehicle include vehicle testing methods, which involve testing the vehicle's driving resistance, establishing road slope data maps to obtain slope information at various locations on the test road, and correcting the slope for driving resistance to obtain the overall vehicle driving resistance.

[0003] However, this method requires prior knowledge of the slope. In scenarios where the slope is unknown, it is impossible to correct for driving resistance based on the slope, resulting in low accuracy in measuring the overall vehicle driving resistance. Summary of the Invention

[0004] Therefore, it is necessary to provide a method, apparatus, computer equipment, computer-readable storage medium, and computer program product for measuring vehicle driving resistance that can improve measurement accuracy, in order to address the above-mentioned technical problems.

[0005] Firstly, this application provides a method for measuring the driving resistance of a vehicle, the method comprising:

[0006] Construct an expression for the overall vehicle driving resistance; the overall vehicle driving resistance in the expression consists of mechanical resistance, aerodynamic resistance, and gradient resistance;

[0007] Acquire measurement data of the target vehicle during a coasting test, and determine the aerodynamic drag value based on the measurement data;

[0008] Substituting the aerodynamic drag value into the vehicle drag expression, we obtain the target vehicle drag expression.

[0009] Construct the wheel-side torque expression for the drive wheel; the wheel-side torque in the wheel-side torque expression includes a first torque and a second torque; the first torque includes the transmission neutral torque loss and the drive axle neutral torque loss, and the second torque includes the drive shaft rolling resistance, the drive shaft internal resistance, and the slope resistance;

[0010] Construct an expression for the mechanical resistance of the whole vehicle; the mechanical resistance of the whole vehicle in the expression includes the first mechanical resistance and the second mechanical resistance; the first mechanical resistance includes transmission loss and drive axle loss, and the second mechanical resistance includes the rolling resistance of the target vehicle, the internal resistance of the target vehicle, and the gradient resistance;

[0011] Based on the value of the wheel-side torque of the drive wheel measured during the coasting test, and after removing the torque loss of the transmission in neutral and the torque loss of the drive axle in neutral, the value of the second mechanical resistance is obtained based on the value of the wheel-side torque and the expression of the mechanical resistance of the whole vehicle.

[0012] Without removing the torque loss in neutral gear of the transmission and the torque loss in neutral gear of the drive axle, the value of the target slope is obtained based on the value of the second mechanical resistance and the expression of the target vehicle driving resistance.

[0013] Substitute the target slope value into the vehicle's driving resistance expression to obtain the vehicle's drag coefficient value, and substitute the target slope value into the vehicle's mechanical resistance expression to obtain the vehicle's rolling resistance coefficient value.

[0014] The value of the vehicle's driving resistance is determined based on the values ​​of the vehicle's drag coefficient and rolling resistance coefficient.

[0015] In one embodiment, aerodynamic drag includes frontal drag and lateral drag; the measurement data includes frontal wind speed, the equivalent mass of the target vehicle, and the vehicle speed of the target vehicle; the step of determining the value of aerodynamic drag based on the measurement data includes:

[0016] The forward wind speed is corrected to obtain the corrected forward wind speed, and the forward wind speed drag value is obtained by fitting based on the corrected forward wind speed.

[0017] Based on equivalent mass and vehicle speed, the value of lateral wind speed drag is obtained by fitting.

[0018] The value of aerodynamic drag is determined based on the values ​​of frontal and lateral wind speed drag.

[0019] In one embodiment, the step of calculating the value of the second mechanical resistance based on the wheel-side torque of the drive wheel measured during a coasting test, and after removing the torque loss in neutral gear of the transmission and the drive axle, based on the wheel-side torque value and the expression for the mechanical resistance of the entire vehicle, includes:

[0020] Obtain the axle load of the drive wheels, and based on the measurement data, determine the equivalent mass of the drive wheels and the equivalent mass of the target vehicle;

[0021] Based on the axle load of the drive wheel, the equivalent mass of the drive wheel, and the equivalent mass of the target vehicle, the proportional relationship between the second torque and the second mechanical resistance is determined.

[0022] After removing the torque loss in neutral gear of the transmission and the torque loss in neutral gear of the drive axle, the expression for mechanical resistance is solved based on the proportional relationship and the value of the wheel-side torque to obtain the value of the second mechanical resistance.

[0023] In one embodiment, the step of solving the mechanical resistance expression based on the proportional relationship and the wheel-side torque value to obtain the value of the second mechanical resistance, after removing the neutral torque loss of the transmission and the neutral torque loss of the drive axle, includes:

[0024] After removing the torque loss in neutral gear of the transmission and the torque loss in neutral gear of the drive axle, the second torque is expressed as an expression related to the second mechanical resistance based on the proportional relationship, and the mechanical resistance expression is updated.

[0025] Based on the value of the wheel-side torque, the updated mechanical resistance expression is solved to obtain the value of the second mechanical resistance.

[0026] In one embodiment, the step of calculating the target slope value based on the value of the second mechanical resistance and the expression for the target vehicle driving resistance, without removing the transmission neutral torque loss and the drive axle neutral torque loss, includes:

[0027] Without removing the torque loss in neutral gear of the transmission and the torque loss in neutral gear of the drive axle, obtain the coasting data of the target vehicle during the coasting test, as well as the measured value of the first mechanical resistance.

[0028] Based on the gliding data, the value of mechanical resistance is obtained by fitting.

[0029] Substitute the values ​​of the mechanical resistance, the first mechanical resistance, and the second mechanical resistance into the expression for the target vehicle's driving resistance to obtain the value of the target slope.

[0030] In one embodiment, the step of substituting the value of the target slope into the mechanical resistance expression to obtain the value of the vehicle rolling resistance coefficient includes:

[0031] Substituting the value of the target slope into the mechanical resistance expression, we obtain the sum of the values ​​of the target vehicle's rolling resistance and the target vehicle's internal resistance.

[0032] Set the internal resistance of the target vehicle to zero, and calculate the rolling resistance of the target vehicle based on the sum of the values.

[0033] Based on the value of the rolling resistance of the target vehicle, the value of the rolling resistance coefficient of the whole vehicle is obtained.

[0034] In one embodiment, the expression for the overall vehicle driving resistance is as follows:

[0035]

[0036] Where, m eV is the equivalent mass of the target vehicle; V is the measured vehicle speed; A is the vehicle's frontal area; A m B is the mechanical resistance coefficient for the zero-order term. m C is the coefficient of mechanical resistance for the first-order term; m The mechanical drag coefficient is the quadratic term; ρ is the air density; CD y V is the drag coefficient of the vehicle at the deviation angle Y; r y is the relative wind speed; a0, a1...a4 are the aerodynamic drag coefficients, which are functions of the deviation angle; Y is the surface wind speed deviation angle relative to the vehicle's direction of travel; m is the vehicle mass; This refers to the road slope.

[0037] In one embodiment, the expression for the wheel-side torque of the constructed drive wheel is:

[0038] F wheel =F gear +F axle +μ*m i *g*cosθ i

[0039] +F ini +m i *g*cotθ i

[0040] Among them, F wheel F is the wheel-side torque of the drive wheel. gear This refers to the torque loss in neutral gear at the corresponding speed of the transmission; F axle The torque loss in neutral at the corresponding speed of the drive axle; μ is the rolling resistance coefficient of the entire vehicle; m i For the axle load of the drive wheel position; θ i F represents the slope value at each location; ini The internal resistance of the drive shaft.

[0041] In one embodiment, the expression for the overall vehicle mechanical resistance is as follows:

[0042]

[0043] Among them, F mesh For the mechanical resistance of the entire vehicle; V is the fitting constant term in the expression for the vehicle's running resistance; V is the measured vehicle speed; A m B is the mechanical resistance coefficient for the zero-order term. m C is the coefficient of mechanical resistance for the first-order term; m θ is the mechanical drag coefficient of the second term; m is the vehicle mass; μ is the rolling resistance coefficient of the whole vehicle; θ i F represents the slope value at each location; gear This refers to the torque loss in neutral gear at the corresponding speed of the transmission; F axleThis refers to the torque loss in neutral at the corresponding speed of the drive axle. For road slope; F in The internal resistance of the target vehicle.

[0044] Secondly, this application also provides a vehicle driving resistance measuring device, the device comprising:

[0045] The first building module is used to construct the expression for the overall vehicle driving resistance; the overall vehicle driving resistance in the expression consists of mechanical resistance, aerodynamic resistance, and gradient resistance;

[0046] The data acquisition module is used to acquire measurement data of the target vehicle during the coasting test and determine the value of aerodynamic drag based on the measurement data;

[0047] The expression acquisition module is used to input the value of aerodynamic drag into the vehicle driving drag expression to obtain the target vehicle driving drag expression;

[0048] The second building module is used to build the wheel-side torque expression of the drive wheel; the wheel-side torque in the wheel-side torque expression includes a first torque and a second torque; the first torque includes the transmission neutral torque loss and the drive axle neutral torque loss, and the second torque includes the drive shaft rolling resistance, the drive shaft internal resistance and the slope resistance;

[0049] The third construction module is used to construct the expression for the mechanical resistance of the whole vehicle. The mechanical resistance of the whole vehicle in the expression includes the first mechanical resistance and the second mechanical resistance. The first mechanical resistance includes the transmission loss and the drive axle loss, and the second mechanical resistance includes the rolling resistance of the target vehicle, the internal resistance of the target vehicle, and the gradient resistance.

[0050] The first solution module is used to calculate the value of the second mechanical resistance based on the value of the wheel-side torque of the drive wheel measured during the coasting test, and after removing the torque loss of the transmission in neutral and the torque loss of the drive axle in neutral, based on the value of the wheel-side torque and the expression of the mechanical resistance of the whole vehicle.

[0051] The second solution module is used to solve for the target slope value based on the value of the second mechanical resistance and the expression of the target vehicle driving resistance without removing the torque loss of the transmission neutral gear and the torque loss of the drive axle neutral gear.

[0052] The third solution module is used to input the value of the target slope into the expression for the vehicle's driving resistance to obtain the value of the vehicle's wind resistance coefficient, and to input the target slope into the expression for the vehicle's mechanical resistance to obtain the value of the vehicle's rolling resistance coefficient.

[0053] The numerical determination module is used to determine the value of the vehicle's driving resistance based on the values ​​of the vehicle's drag coefficient and rolling resistance coefficient.

[0054] Thirdly, this application also provides a computer device including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the method steps of any one of the first aspects.

[0055] Fourthly, this application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method steps of any one of the first aspects.

[0056] Fifthly, this application also provides a computer program product, which includes a computer program that, when executed by a processor, implements the method steps of any one of the first aspects.

[0057] The aforementioned vehicle drag measurement method, device, computer equipment, storage medium, and computer program product acquire measurement data of the target vehicle during a coasting test to determine the aerodynamic drag value. This aerodynamic drag value is then substituted into the vehicle drag expression, which comprises mechanical drag, aerodynamic drag, and gradient drag, to obtain the target vehicle drag expression. Subsequently, based on the wheel-side torque values ​​of the drive wheels measured during the coasting test, and after removing the neutral torque losses of the transmission and drive axle, the value of the second mechanical drag in the vehicle mechanical drag expression is obtained. This is done without removing the neutral torque losses of the transmission and drive axle. In this case, based on the value of the second mechanical resistance and the expression for the target vehicle driving resistance, the value of the target slope is obtained to eliminate the influence of the unknown slope on the vehicle driving resistance. Then, the value of the target slope is substituted into the expression for the vehicle driving resistance to obtain the value of the vehicle's drag coefficient. Similarly, the value of the target slope is substituted into the expression for the vehicle's mechanical resistance to obtain the value of the vehicle's rolling resistance coefficient. By obtaining the value of the target slope, the value of the slope resistance can be accurately calculated, and the driving resistance can be corrected for the road slope to avoid the slope affecting the vehicle's driving resistance. Thus, based on the values ​​of the vehicle's drag coefficient and rolling resistance coefficient, a more accurate value of the vehicle's driving resistance is obtained. Attached Figure Description

[0058] Figure 1 This is an application environment diagram of the vehicle driving resistance measurement method in one embodiment;

[0059] Figure 2 This is a flowchart illustrating a method for measuring the overall vehicle driving resistance in one embodiment;

[0060] Figure 3 This is a flowchart illustrating the steps for solving the value of the second mechanical resistance in one embodiment;

[0061] Figure 4 This is a flowchart illustrating a method for measuring the overall vehicle driving resistance in one embodiment;

[0062] Figure 5 This is a flowchart illustrating the steps for solving the road slope in one embodiment;

[0063] Figure 6 This is a structural block diagram of a vehicle driving resistance measuring device in one embodiment;

[0064] Figure 7 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation

[0065] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0066] The vehicle driving resistance measurement method provided in this application embodiment can be applied to, for example... Figure 1 In the application environment shown, terminal 102 communicates with measuring device 104 via a network. Measuring device 104 measures data from the target vehicle during a coasting test, including the wheel torque values ​​of the drive wheels. Terminal 102 acquires the measurement data from the target vehicle during the coasting test, determines the aerodynamic drag value based on the measurement data, and, based on the measured wheel torque values ​​of the drive wheels during the coasting test, calculates the value of the second mechanical drag in the overall vehicle mechanical drag expression based on the wheel torque values ​​and the overall vehicle mechanical drag expression, after removing the torque loss from the transmission neutral gear and the drive axle neutral gear. Terminal 102 is also used to, without removing the torque loss in neutral gear of the transmission and the drive axle, calculate the target slope value based on the value of the second mechanical resistance and the expression for the target vehicle driving resistance. Substituting the target slope value into the vehicle driving resistance expression, the vehicle drag coefficient value is calculated. Substituting the target slope value into the vehicle mechanical resistance expression, the vehicle rolling resistance coefficient value is calculated. Therefore, based on the values ​​of the vehicle drag coefficient and the vehicle rolling resistance coefficient, the value of the vehicle driving resistance is determined. Terminal 102 can be, but is not limited to, various personal computers and laptops. The measuring device 104 can be implemented using a separate measuring device or multiple measuring devices.

[0067] In one embodiment, such as Figure 2 As shown, a method for measuring the driving resistance of a vehicle is provided, which can be applied to... Figure 1Taking terminal 102 as an example, the explanation includes the following steps:

[0068] S202: Construct the expression for the overall vehicle driving resistance; the overall vehicle driving resistance in the expression consists of mechanical resistance, aerodynamic resistance, and gradient resistance.

[0069] Driving resistance includes mechanical resistance, acceleration resistance, aerodynamic resistance, and gradient resistance. Mechanical resistance and aerodynamic resistance exist under all driving conditions, while gradient resistance and acceleration resistance exist only under certain driving conditions. For example, there is no gradient resistance when driving on a level road. When the vehicle is coasting, there is no acceleration resistance. In the final vehicle driving resistance expression, the total vehicle driving resistance is composed of mechanical resistance, aerodynamic resistance, and gradient resistance.

[0070] S204: Acquire measurement data of the target vehicle during a coasting test, and determine the value of aerodynamic drag based on the measurement data.

[0071] Aerodynamic drag includes frontal wind speed drag and lateral wind speed drag. Frontal wind speed drag refers to the drag caused by the frontal wind speed directly in front of the vehicle's direction of travel, while lateral wind speed drag refers to the drag caused by the lateral wind speed deviating from the vehicle's direction of travel during the coasting test. Measurement data includes frontal wind speed, the equivalent mass of the target vehicle, and the target vehicle's speed. Frontal wind speed can be measured by an anemometer, and the target vehicle's speed can be obtained from the target vehicle's instruments. Under the condition of equal kinetic energy, the mass of each component of the mechanism can be replaced by a hypothetical mass at a point on the equivalent component; this hypothetical mass is called the equivalent mass of the mechanism. The terminal calculates the equivalent mass based on the measured mass of the target vehicle. The terminal obtains the frontal wind speed drag based on the frontal wind speed and the relative wind speed based on the frontal wind speed. The relative wind speed is used to calculate the lateral wind speed drag. Thus, the terminal determines the value of the aerodynamic drag based on the frontal wind speed drag and the lateral wind speed drag.

[0072] S206: Substitute the aerodynamic drag value into the vehicle drag expression to obtain the target vehicle drag expression.

[0073] The terminal substitutes the aerodynamic drag value into the vehicle driving resistance expression to obtain the target vehicle driving resistance expression. The vehicle driving resistance in the expression consists of mechanical resistance and gradient resistance. Since the mechanical resistance value can be calculated from the data of the target vehicle during the coasting process, the value of the vehicle driving resistance can be calculated by solving for the gradient resistance.

[0074] S208: Construct the wheel-side torque expression for the drive wheel; the wheel-side torque in the wheel-side torque expression includes a first torque and a second torque; the first torque includes the transmission neutral torque loss and the drive axle neutral torque loss, and the second torque includes the drive shaft rolling resistance, drive shaft internal resistance, and gradient resistance.

[0075] Since all resistance encountered by the vehicle ultimately manifests at the wheel edges, the terminal constructs a wheel edge torque expression based on the torque transmission relationship of the drive wheels. This wheel edge torque expression includes a first torque and a second torque. The first torque includes the transmission neutral torque loss and the drive axle neutral torque loss. The second torque includes the drive shaft rolling resistance, drive shaft internal resistance, and gradient resistance. The transmission neutral torque loss refers to the transmission efficiency loss at a corresponding speed, and the drive axle neutral torque loss refers to the drive axle efficiency loss at a corresponding speed. Furthermore, the wheel edge torque is also affected by the drive shaft rolling resistance, drive shaft internal resistance, and gradient resistance.

[0076] S210: Construct the expression for the mechanical resistance of the whole vehicle; the mechanical resistance of the whole vehicle in the expression includes the first mechanical resistance and the second mechanical resistance; the first mechanical resistance includes the transmission loss and the drive axle loss, and the second mechanical resistance includes the rolling resistance of the target vehicle, the internal resistance of the target vehicle, and the gradient resistance.

[0077] The vehicle mechanical resistance expression constructed by the terminal includes a first mechanical resistance and a second mechanical resistance. The first mechanical resistance includes transmission losses and drive axle losses. Transmission losses refer to the portion of mechanical resistance caused by transmission efficiency losses, and drive axle losses refer to the portion of mechanical resistance caused by drive axle efficiency losses.

[0078] Since the target vehicle is in a coasting test, the slope resistance is included in the overall vehicle mechanical resistance after removing the acceleration resistance. The specific slope resistance has been calculated through the overall vehicle mechanical resistance. Therefore, the second mechanical resistance includes the target vehicle's rolling resistance, the target vehicle's internal resistance, and the slope resistance.

[0079] S212: Based on the value of the wheel-side torque of the drive wheel measured during the coasting test, and after removing the torque loss in neutral gear of the transmission and the torque loss in neutral gear of the drive axle, the value of the second mechanical resistance is obtained based on the value of the wheel-side torque and the expression of the mechanical resistance of the whole vehicle.

[0080] In this case, after removing the torque loss in the neutral gear of the transmission and the torque loss in the neutral gear of the drive axle, the mechanical resistance of the whole vehicle in the expression of the whole vehicle mechanical resistance only includes the second mechanical resistance. Since the drive shaft related resistance has a certain proportional relationship with the second mechanical resistance, the end is based on the value of the wheel-side torque of the drive wheel measured during the coasting test to solve the expression of the whole vehicle mechanical resistance and obtain the value of the second mechanical resistance.

[0081] S214: Without removing the torque loss in neutral gear of the transmission and the torque loss in neutral gear of the drive axle, the target slope value is obtained based on the value of the second mechanical resistance and the expression for the target vehicle driving resistance.

[0082] After solving for the value of the second mechanical resistance, the terminal uses the coasting data of the target vehicle during the coasting test to fit and obtain the value of the whole vehicle mechanical resistance. Furthermore, the transmission loss and drive axle loss in the first mechanical resistance can be calculated from the coasting data. Therefore, the value of the first mechanical resistance can be obtained. The terminal substitutes the values ​​of the whole vehicle mechanical resistance, the first mechanical resistance, and the second mechanical resistance into the expression for the target whole vehicle driving resistance, solves the expression for the target whole vehicle driving resistance, and obtains the value of the target slope.

[0083] S216: Substitute the target slope value into the vehicle's driving resistance expression to obtain the vehicle's drag coefficient value, and substitute the target slope into the vehicle's mechanical resistance expression to obtain the vehicle's rolling resistance coefficient value.

[0084] Specifically, the terminal substitutes the target slope value into the vehicle driving resistance expression, solves for the vehicle drag coefficient in the positive wind speed resistance fitted in the vehicle driving resistance expression, and obtains the value of the vehicle drag coefficient. Similarly, the terminal substitutes the target slope into the vehicle mechanical resistance expression, solves for the vehicle rolling resistance coefficient in the second mechanical resistance, and obtains the value of the vehicle rolling resistance coefficient.

[0085] S218: Determine the value of the vehicle's driving resistance based on the values ​​of the vehicle's drag coefficient and rolling resistance coefficient.

[0086] Among them, based on the values ​​of the vehicle drag coefficient and the vehicle rolling resistance coefficient, more accurate vehicle drag and rolling resistance can be calculated. In practical applications, if the vehicle is in a coasting test and acceleration resistance is ignored, the vehicle's overall driving resistance can be directly calculated by solving for the values ​​of the vehicle drag coefficient and the vehicle rolling resistance coefficient.

[0087] In the aforementioned method for measuring vehicle drag, measurement data of the target vehicle during a coasting test is obtained. Based on this data, the aerodynamic drag value can be determined. This aerodynamic drag value is then substituted into the vehicle drag expression, which comprises mechanical drag, aerodynamic drag, and gradient drag, to obtain the target vehicle drag expression. Next, based on the wheel-side torque values ​​of the drive wheels measured during the coasting test, and after removing the neutral torque losses of the transmission and drive axle, the value of the second mechanical drag in the vehicle mechanical drag expression is obtained. Finally, without removing the neutral torque losses of the transmission and drive axle, the value of the second mechanical drag is calculated. By calculating the values ​​of mechanical resistance and the target vehicle running resistance expression, the value of the target slope is obtained to eliminate the influence of the unknown slope on the vehicle running resistance. Then, the value of the target slope is substituted into the vehicle running resistance expression to obtain the vehicle's drag coefficient. Similarly, the target slope is substituted into the vehicle mechanical resistance expression to obtain the vehicle's rolling resistance coefficient. By obtaining the target slope value, the slope resistance value can be accurately calculated, allowing for correction of the running resistance based on the road slope and preventing the slope from affecting the vehicle's running resistance. Therefore, based on the values ​​of the vehicle's drag coefficient and rolling resistance coefficient, a more accurate value of the vehicle's running resistance is obtained.

[0088] In one embodiment, aerodynamic drag includes frontal wind speed drag and lateral wind speed drag; the measurement data includes frontal wind speed, the equivalent mass of the target vehicle, and the vehicle speed of the target vehicle; the step of determining the value of aerodynamic drag based on the measurement data includes: correcting the frontal wind speed to obtain a corrected frontal wind speed, and fitting the value of frontal wind speed drag based on the corrected frontal wind speed; fitting the value of lateral wind speed drag based on the equivalent mass and vehicle speed; and determining the value of aerodynamic drag based on the values ​​of frontal wind speed drag and lateral wind speed drag.

[0089] The terminal corrects the measured forward wind speed to obtain the corrected actual wind speed. Based on this corrected forward wind speed, it fits a value for forward wind speed drag, which is derived from historical data. Next, the terminal fits a value for lateral wind speed drag based on equivalent mass and vehicle speed. This lateral wind speed drag value is obtained by fitting a multivariate polynomial equation. Using both the forward and lateral wind speed drag values, the terminal can determine the aerodynamic drag value.

[0090] In this embodiment, the forward wind speed is corrected to obtain the corrected forward wind speed, and the forward wind speed drag value is obtained by fitting based on the corrected forward wind speed. Then, based on the equivalent mass and vehicle speed, the lateral wind speed drag value is obtained by fitting, thereby determining the aerodynamic drag value. This simplifies the expression of the vehicle's driving drag and reduces the complexity of subsequent calculations based on the expression of the vehicle's driving drag.

[0091] In one embodiment, such as Figure 3 As shown, the steps for calculating the value of the second mechanical resistance based on the wheel-side torque of the drive wheel measured during the coasting test, and after removing the torque loss in neutral gear of the transmission and the drive axle, based on the wheel-side torque value and the expression for the mechanical resistance of the entire vehicle, include:

[0092] S302: Obtain the axle load of the drive wheels and, based on the measurement data, determine the equivalent mass of the drive wheels and the equivalent mass of the target vehicle.

[0093] Among them, the axle load of the drive wheel refers to the load borne by the drive wheel. Based on the axle load of the drive wheel and the measurement data, the terminal calculates the equivalent mass of the drive wheel and the equivalent mass of the target vehicle.

[0094] S304: Determine the proportional relationship between the second torque and the second mechanical resistance based on the axle load of the drive wheel, the equivalent mass of the drive wheel, and the equivalent mass of the target vehicle.

[0095] The second torque includes the rolling resistance of the drive shaft, the internal resistance of the drive shaft, and the slope resistance. The second mechanical resistance includes the rolling resistance of the target vehicle, the internal resistance of the target vehicle, and the slope resistance. After removing the torque loss in neutral gear of the transmission and the drive axle, the second mechanical resistance and the second torque are proportionally distributed based on the axle load and equivalent mass. In other words, the proportional relationship between the second mechanical resistance and the second torque is related to mass and equivalent mass. The terminal determines the proportional relationship between the second torque and the second mechanical resistance based on the axle load of the drive wheels, the equivalent mass of the drive wheels, and the equivalent mass of the target vehicle.

[0096] S306: After removing the torque loss in neutral gear of the transmission and the torque loss in neutral gear of the drive axle, the expression for mechanical resistance is solved based on the proportional relationship and the value of the wheel-side torque to obtain the value of the second mechanical resistance.

[0097] Specifically, after removing the torque loss in neutral gear of the transmission and the torque loss in neutral gear of the drive axle, the terminal expresses the second torque as an expression related to the second mechanical resistance based on the proportional relationship and the value of the wheel-side torque. Thus, by solving the mechanical resistance expression and the wheel-side torque expression simultaneously, the value of the second mechanical resistance is obtained.

[0098] In this embodiment, the equivalent mass of the drive wheel and the equivalent mass of the target vehicle are determined by the axle load and measurement data of the drive wheel. Then, the proportional relationship between the second torque and the second mechanical resistance is determined. After removing the torque loss in neutral gear of the transmission and the drive axle, the expression for mechanical resistance is solved based on the proportional relationship and the value of the wheel-side torque. The value of the second mechanical resistance can be accurately obtained, providing a data basis for the subsequent calculation of the target slope value, so as to ensure the accurate acquisition of the target slope value and thus improve the accuracy of the overall vehicle driving resistance.

[0099] In one embodiment, the step of solving the mechanical resistance expression based on the proportional relationship and the wheel-side torque value to obtain the value of the second mechanical resistance, after removing the neutral torque loss of the transmission and the neutral torque loss of the drive axle, includes: after removing the neutral torque loss of the transmission and the neutral torque loss of the drive axle, expressing the second torque as an expression related to the second mechanical resistance based on the proportional relationship, and updating the mechanical resistance expression; and solving the updated mechanical resistance expression based on the wheel-side torque value to obtain the value of the second mechanical resistance.

[0100] The expression for the wheel-side torque is as follows:

[0101] F wheel =F gear +F axle +μ*m i *g*cosθ i

[0102] +F ini +m i *g*cotθ i

[0103] Among them, F wheel F is the wheel-side torque of the drive wheel. gear This refers to the torque loss in neutral gear at the corresponding speed of the transmission; F axle The torque loss in neutral at the corresponding speed of the drive axle; μ is the rolling resistance coefficient of the entire vehicle; m i For the axle load of the drive wheel position; θ i F represents the slope value at each location; ini The internal resistance of the drive shaft.

[0104] The expression for the mechanical resistance of the whole vehicle is:

[0105]

[0106] Among them, F mesh For the mechanical resistance of the entire vehicle; V is the fitting constant term in the expression for the vehicle's running resistance; V is the measured vehicle speed; A mB is the mechanical resistance coefficient for the zero-order term. m C is the coefficient of mechanical resistance for the first-order term; m θ is the mechanical drag coefficient of the second term; m is the vehicle mass; μ is the rolling resistance coefficient of the whole vehicle; θ i F represents the slope value at each location; gear This refers to the torque loss in neutral gear at the corresponding speed of the transmission; F axle This refers to the torque loss in neutral at the corresponding speed of the drive axle. For road slope; F in The internal resistance of the target vehicle.

[0107] Wherein, after removing the torque loss in neutral gear of the transmission and the torque loss in neutral gear of the drive axle, the expression for the second torque is:

[0108] F wheel_f =F wheel -F gear -F axle

[0109] =μ*m i *g*cosθ i +F ini +m i *g*cotθ i

[0110] Among them, F wheel_f For the first torque, F wheel F is the wheel-side torque of the drive wheel. gear This refers to the torque loss in neutral gear at the corresponding speed of the transmission; F axle The torque loss in neutral at the corresponding speed of the drive axle; μ is the rolling resistance coefficient of the entire vehicle; m i For the axle load of the drive wheel position; θ i F represents the slope value at each location; ini The internal resistance of the drive shaft.

[0111] Specifically, the terminal, based on a proportional relationship, expresses the second torque as an expression related to the second mechanical resistance, and updates the mechanical resistance expression. The expression for the proportional relationship is as follows:

[0112]

[0113] Among them, F wheel_veh For the second mechanical resistance; F wheel_f The first torque is m; m is the vehicle mass; m i For the axle load of the drive wheel position; m e m is the equivalent mass of the target vehicle. ei The equivalent mass of the drive shaft.

[0114] The updated expression for mechanical resistance is:

[0115]

[0116] Among them, F mesh For the mechanical resistance of the entire vehicle; F gear This refers to the torque loss in neutral gear at the corresponding speed of the transmission; F axle θ represents the neutral torque loss at the corresponding speed of the drive axle; m is the vehicle mass; μ is the vehicle rolling resistance coefficient; θ i These are the slope values ​​at each location; For road slope; F in The internal resistance of the target vehicle.

[0117] The terminal solves the updated mechanical resistance expression based on the wheel-side torque value to obtain the value of the second mechanical resistance.

[0118] In this embodiment, after removing the torque loss in neutral gear of the transmission and the torque loss in neutral gear of the drive axle, the second torque is expressed as an expression related to the second mechanical resistance through a proportional relationship, and the mechanical resistance expression is updated. Based on the value of the wheel-side torque, the updated mechanical resistance expression is solved to accurately obtain the value of the second mechanical resistance, providing a data basis for subsequently solving the value of the target slope, thereby ensuring the accurate acquisition of the target slope value and improving the accuracy of the vehicle's driving resistance.

[0119] In one embodiment, the step of calculating the target slope value based on the value of the second mechanical resistance and the expression for the target vehicle's driving resistance, without removing the torque loss in the neutral gear of the transmission and the torque loss in the neutral gear of the drive axle, includes: acquiring coasting data of the target vehicle during a coasting test and the measured value of the first mechanical resistance, without removing the torque loss in the neutral gear of the transmission and the torque loss in the neutral gear of the drive axle; fitting the mechanical resistance value based on the coasting data; and substituting the mechanical resistance value, the first mechanical resistance value, and the second mechanical resistance value into the expression for the target vehicle's driving resistance to calculate the target slope value.

[0120] This includes coasting data of the target vehicle during a coasting test, without removing torque losses in the neutral gears of the transmission and drive axle. The terminal then uses this coasting data to fit and obtain the mechanical resistance values. These values, along with the values ​​of the first and second mechanical resistances, are then substituted into the target vehicle's overall driving resistance expression to solve for the target slope.

[0121] Specifically, the terminal can obtain the following based on the updated mechanical resistance expression:

[0122]

[0123] Among them, F mesh For the mechanical resistance of the entire vehicle; F gear This refers to the torque loss in neutral gear at the corresponding speed of the transmission; F axle This refers to the torque loss in neutral at the corresponding speed of the drive axle; F wheel_veh θ represents the second mechanical resistance; m represents the vehicle mass; θ represents the second mechanical resistance. i These are the slope values ​​at each location; This refers to the road slope.

[0124] The terminal inputs the values ​​of mechanical resistance, the first mechanical resistance, and the second mechanical resistance into the expression for the target vehicle driving resistance to obtain the value of the target slope.

[0125] In this embodiment, without removing the torque loss in neutral gear of the transmission and the torque loss in neutral gear of the drive axle, the value of mechanical resistance is obtained by fitting the coasting data and the value of the first mechanical resistance. The values ​​of mechanical resistance, the first mechanical resistance, and the second mechanical resistance are then substituted into the expression for the target vehicle driving resistance to solve for the value of the target slope. The value of the target slope can be accurately obtained, and thus the values ​​of the vehicle drag coefficient and the vehicle rolling resistance coefficient can be accurately obtained, thereby obtaining a high-precision vehicle driving resistance.

[0126] In one embodiment, the step of substituting the value of the target slope into the mechanical resistance expression to obtain the value of the vehicle rolling resistance coefficient includes: substituting the value of the target slope into the mechanical resistance expression to obtain the sum of the values ​​of the target vehicle rolling resistance and the target vehicle internal resistance; setting the value of the target vehicle internal resistance to zero and calculating the value of the target vehicle rolling resistance based on the sum of the values; and obtaining the value of the vehicle rolling resistance coefficient based on the value of the target vehicle rolling resistance.

[0127] The terminal substitutes the target slope value into the mechanical resistance expression to obtain the sum of the target vehicle rolling resistance and the target vehicle internal resistance. Since the target vehicle internal resistance is related to bearing friction, which cannot be accurately measured, the terminal includes the target vehicle internal resistance in the target vehicle rolling resistance and sets the target vehicle internal resistance value to zero to obtain the vehicle rolling resistance value. Based on the vehicle rolling resistance value and expression, the value of the overall vehicle rolling resistance coefficient is obtained.

[0128] In this embodiment, by substituting the value of the target slope into the mechanical resistance expression, the sum of the target vehicle rolling resistance and the target vehicle internal resistance is obtained. The value of the target vehicle internal resistance is set to zero, and the value of the target vehicle rolling resistance is calculated. Based on the value of the target vehicle rolling resistance, the value of the vehicle rolling resistance coefficient can be accurately obtained, and the vehicle rolling resistance can be accurately calculated, thereby obtaining a more accurate vehicle driving resistance.

[0129] In one embodiment, the expression for the overall vehicle driving resistance is as follows:

[0130]

[0131] Where, m e V is the equivalent mass of the target vehicle; V is the measured vehicle speed; A is the vehicle's frontal area; A m B is the mechanical resistance coefficient for the zero-order term. m C is the coefficient of mechanical resistance for the first-order term; m The mechanical drag coefficient is the quadratic term; ρ is the air density; CD y V is the drag coefficient of the vehicle at the deviation angle Y; r y is the relative wind speed; a0, a1...a4 are the aerodynamic drag coefficients, which are functions of the deviation angle; Y is the surface wind speed deviation angle relative to the vehicle's direction of travel; m is the vehicle mass; This refers to the road slope.

[0132] In this embodiment, by constructing an expression for the overall vehicle driving resistance, the overall vehicle driving resistance can be decomposed into mechanical resistance, aerodynamic resistance, and slope resistance. Based on the fitted aerodynamic resistance, the slope resistance and mechanical resistance are solved to obtain the target slope. Then, based on the target slope and the expression for the overall vehicle driving resistance, the normal drag coefficient and normal rolling resistance coefficient are solved to obtain a more accurate overall vehicle driving resistance.

[0133] In one embodiment, the expression for the wheel-side torque of the constructed drive wheel is:

[0134] F wheel =F gear +F axle +μ*m i *g*cosθ i

[0135] +F ini +m i *g*cotθ i

[0136] Among them, F wheel F is the wheel-side torque of the drive wheel. gear This refers to the torque loss in neutral gear at the corresponding speed of the transmission; F axleThe torque loss in neutral at the corresponding speed of the drive axle; μ is the rolling resistance coefficient of the entire vehicle; m i For the axle load of the drive wheel position; θ i F represents the slope value at each location; ini The internal resistance of the drive shaft.

[0137] In this embodiment, by constructing the wheel-side torque expression of the drive wheel, the sum of the values ​​of the drive shaft rolling resistance, drive shaft internal resistance, and slope resistance can be calculated after removing the torque loss of the drive axle in neutral and the torque loss of the transmission in neutral. Thus, without removing the torque loss of the drive axle in neutral and the torque loss of the transmission in neutral, the sum of the values ​​of the target vehicle rolling resistance, target vehicle internal resistance, and slope resistance can be calculated based on the sum of the values.

[0138] In one embodiment, the expression for the overall vehicle mechanical resistance is as follows:

[0139]

[0140] Among them, F mesh For the mechanical resistance of the entire vehicle; V is the fitting constant term in the expression for the vehicle's running resistance; V is the measured vehicle speed; A m B is the mechanical resistance coefficient for the zero-order term. m C is the coefficient of mechanical resistance for the first-order term; m θ is the mechanical drag coefficient of the second term; m is the vehicle mass; μ is the rolling resistance coefficient of the whole vehicle; θ i F represents the slope value at each location; gear This refers to the torque loss in neutral gear at the corresponding speed of the transmission; F axle This refers to the torque loss in neutral at the corresponding speed of the drive axle. For road slope; F in The internal resistance of the target vehicle.

[0141] In this embodiment, by constructing an expression for the mechanical resistance of the entire vehicle, the accurate value of the rolling resistance coefficient of the entire vehicle can be obtained based on the expression for the mechanical resistance of the entire vehicle, thereby obtaining a more accurate value for the vehicle's driving resistance.

[0142] In one embodiment, such as Figure 4 As shown, a method for measuring the driving resistance of a vehicle is provided.

[0143] S1: The terminal acquires the axle load of the target vehicle in a ready state: the ready state refers to the weight of the target vehicle after it is fully equipped (such as spare tire, tools, etc. are installed) and all fluids are filled. The terminal acquires the axle load of each axle measured by the measuring equipment and can calculate the mass of the target vehicle, etc.

[0144] S2: Vehicle coasting test: The vehicle speed is gradually coasted to 0 in segments of 90-80km / h, 85-75km / h...30-0km / h.

[0145] S3: Anemometer Wind Speed ​​Correction: The terminal acquires the forward wind speed measured by the anemometer, corrects the measured forward wind speed to obtain the corrected actual wind speed, and then fits the corrected forward wind speed to obtain the value of the forward wind speed resistance.

[0146] S4: Road Slope Calculation: The specific steps for solving the road slope problem are as follows: Figure 5 As shown.

[0147] S41: Vehicle Driving Resistance Expression Update: The terminal substitutes the aerodynamic drag value into the vehicle driving resistance expression to obtain the target vehicle driving resistance expression. This makes the vehicle driving resistance in the expression consist of mechanical resistance and gradient resistance. Furthermore, since the mechanical resistance value can be calculated from the data of the target vehicle during the coasting process, only the gradient resistance needs to be solved to calculate the value of the vehicle driving resistance.

[0148] S42: Constant term fitting result update: While the terminal performs equation fitting on the vehicle driving resistance expression to obtain the value of lateral wind speed resistance, it can also fit the constant term in the vehicle driving resistance expression, expressing the constant term as the sum of the 0th degree mechanical resistance coefficient and the slope resistance.

[0149] S43: Wheel-side torque decomposition: The terminal constructs the wheel-side torque expression of the drive wheel, decomposing the wheel-side torque into a first torque and a second torque. The first torque includes the transmission neutral torque loss and the drive axle neutral torque loss, while the second torque includes the drive shaft rolling resistance, drive shaft internal resistance, and slope resistance.

[0150] S44: Mechanical Resistance Decomposition: The terminal constructs the expression for the mechanical resistance of the whole vehicle, decomposing the mechanical resistance of the whole vehicle into the first mechanical resistance and the second mechanical resistance. The first mechanical resistance includes transmission loss and drive axle loss, and the second mechanical resistance includes the rolling resistance of the target vehicle, the internal resistance of the target vehicle, and the gradient resistance.

[0151] S45: Summation of vehicle internal resistance: After removing the torque loss of the transmission in neutral and the torque loss of the drive axle in neutral, the terminal calculates the value of the second mechanical resistance based on the value of the wheel-side torque of the drive wheel measured during the coasting test and the expression of the mechanical resistance of the whole vehicle. This value is the sum of the values ​​of the rolling resistance of the target vehicle, the internal resistance of the target vehicle, and the slope resistance.

[0152] S46: Road slope calculation: Without removing the torque loss in neutral gear of the transmission and the torque loss in neutral gear of the drive axle, the terminal calculates the target slope value based on the value of the second mechanical resistance and the updated expression of the vehicle driving resistance.

[0153] S5: Calculation of vehicle drag coefficient: The terminal substitutes the value of the target slope into the expression for vehicle driving resistance to obtain the value of the vehicle drag coefficient.

[0154] S6: Calculation of rolling resistance coefficient of the whole vehicle: The terminal substitutes the target slope into the expression of mechanical resistance of the whole vehicle to obtain the sum of the rolling resistance and internal resistance of the target vehicle. Then, the value of the internal resistance of the target vehicle is set to zero, and the value of the rolling resistance of the target vehicle is calculated based on the sum of the values. Based on the value of the rolling resistance of the target vehicle, the value of the rolling resistance coefficient of the whole vehicle is obtained.

[0155] In this embodiment, by analyzing the influence of wind speed and road slope on the vehicle's driving resistance during the test, the vehicle's drag coefficient and rolling resistance coefficient can be accurately calculated, resulting in a high-precision vehicle driving resistance.

[0156] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0157] Based on the same inventive concept, this application also provides a vehicle driving resistance measuring device for implementing the above-mentioned vehicle driving resistance measuring method. The solution provided by this device is similar to the solution described in the above method. Therefore, the specific limitations of one or more vehicle driving resistance measuring device embodiments provided below can be found in the limitations of the vehicle driving resistance measuring method above, and will not be repeated here.

[0158] In one embodiment, such as Figure 6As shown, a vehicle driving resistance measurement device is provided, comprising: a first construction module 10, a data acquisition module 20, an expression acquisition module 30, a second construction module 40, a third construction module 50, a first solving module 60, a second solving module 70, a third solving module 80, and a numerical determination module 90, wherein:

[0159] The first construction module 10 is used to construct the vehicle driving resistance expression; the vehicle driving resistance in the vehicle driving resistance expression consists of mechanical resistance, aerodynamic resistance and gradient resistance;

[0160] The data acquisition module 20 is used to acquire measurement data of the target vehicle during the coasting test and determine the value of aerodynamic drag based on the measurement data;

[0161] The expression acquisition module 30 is used to input the value of aerodynamic drag into the vehicle driving drag expression to obtain the target vehicle driving drag expression;

[0162] The second building module 40 is used to build the wheel-side torque expression of the drive wheel; the wheel-side torque in the wheel-side torque expression includes a first torque and a second torque; the first torque includes the transmission neutral torque loss and the drive axle neutral torque loss, and the second torque includes the drive shaft rolling resistance, the drive shaft internal resistance and the slope resistance;

[0163] The third construction module 50 is used to construct the vehicle mechanical resistance expression; the vehicle mechanical resistance in the vehicle mechanical resistance expression includes the first mechanical resistance and the second mechanical resistance; the first mechanical resistance includes transmission loss and drive axle loss, and the second mechanical resistance includes the target vehicle rolling resistance, the target vehicle internal resistance, and the gradient resistance;

[0164] The first solution module 60 is used to calculate the value of the second mechanical resistance based on the value of the wheel-side torque of the drive wheel measured during the coasting test, and after removing the torque loss of the transmission in neutral and the torque loss of the drive axle in neutral, based on the value of the wheel-side torque and the expression of the mechanical resistance of the whole vehicle.

[0165] The second solving module 70 is used to solve for the target slope value based on the value of the second mechanical resistance and the expression of the target vehicle driving resistance without removing the torque loss of the transmission neutral gear and the torque loss of the drive axle neutral gear.

[0166] The third solution module 80 is used to input the value of the target slope into the vehicle driving resistance expression to obtain the value of the vehicle drag coefficient, and to input the target slope into the vehicle mechanical resistance expression to obtain the value of the vehicle rolling resistance coefficient.

[0167] The numerical determination module 90 is used to determine the value of the vehicle's driving resistance based on the values ​​of the vehicle's drag coefficient and rolling resistance coefficient.

[0168] In one embodiment, aerodynamic drag includes frontal wind speed drag and lateral wind speed drag; the measurement data includes frontal wind speed, the equivalent mass of the target vehicle, and the vehicle speed of the target vehicle; the data acquisition module 20 includes: a wind speed correction unit, a wind speed fitting unit, and a numerical determination unit.

[0169] The wind speed correction unit is used to correct the forward wind speed, obtain the corrected forward wind speed, and fit the forward wind speed drag value based on the corrected forward wind speed.

[0170] The wind speed fitting unit, based on equivalent mass and vehicle speed, fits the value of lateral wind speed drag.

[0171] The numerical determination unit is used to determine the value of aerodynamic drag based on the values ​​of forward wind speed drag and lateral wind speed drag.

[0172] In one embodiment, the first solving module 60 includes a mass determination unit, a scale determination unit, and a numerical solving unit, wherein:

[0173] The mass determination unit is used to acquire the axle load of the drive wheels and, based on the measurement data, determine the equivalent mass of the drive wheels and the equivalent mass of the target vehicle.

[0174] The proportional determination unit is used to determine the proportional relationship between the second torque and the second mechanical resistance based on the axle load of the drive wheel, the equivalent mass of the drive wheel, and the equivalent mass of the target vehicle.

[0175] The numerical solution unit is used to solve the mechanical resistance expression based on the proportional relationship and the value of the wheel-side torque, after removing the torque loss in neutral gear of the transmission and the drive axle, so as to obtain the value of the second mechanical resistance.

[0176] In one embodiment, the numerical solution unit includes: an expression update subunit and a numerical solution subunit, wherein:

[0177] The expression update sub-unit is used to express the second torque as an expression related to the second mechanical resistance based on the proportional relationship, after removing the torque loss in neutral gear of the transmission and the torque loss in neutral gear of the drive axle, and to update the mechanical resistance expression.

[0178] The numerical solution sub-unit is used to solve the updated mechanical resistance expression based on the wheel-side torque value to obtain the value of the second mechanical resistance.

[0179] In one embodiment, the second solving module 70 includes: a data acquisition unit, a data fitting unit, and a numerical solving unit, wherein:

[0180] The data acquisition unit is used to acquire coasting data of the target vehicle during a coasting test, as well as the measured value of the first mechanical resistance, without removing the torque loss in neutral gear of the transmission and the torque loss in neutral gear of the drive axle.

[0181] The data fitting unit is used to fit the mechanical resistance value based on the sliding data.

[0182] The numerical solution unit is used to input the values ​​of mechanical resistance, the first mechanical resistance, and the second mechanical resistance into the target vehicle driving resistance expression to obtain the target slope value.

[0183] In one embodiment, the third solving module 80 includes: a sum acquisition unit, a numerical calculation unit, and a numerical solving unit, wherein:

[0184] The summation unit is used to input the value of the target slope into the mechanical resistance expression to obtain the sum of the target vehicle's rolling resistance and the target vehicle's internal resistance.

[0185] The numerical calculation unit is used to set the internal resistance of the target vehicle to zero and calculate the rolling resistance of the target vehicle based on the sum of the values.

[0186] The numerical solution unit is used to solve for the numerical value of the rolling resistance coefficient of the whole vehicle based on the numerical value of the rolling resistance of the target vehicle.

[0187] In one embodiment, the expression for the vehicle's driving resistance constructed by the first construction module 10 is:

[0188]

[0189] Where, m e V is the equivalent mass of the target vehicle; V is the measured vehicle speed; A is the vehicle's frontal area; A m B is the mechanical resistance coefficient for the zero-order term. m C is the coefficient of mechanical resistance for the first-order term; m The mechanical drag coefficient is the quadratic term; ρ is the air density; CD y V is the drag coefficient of the vehicle at the deviation angle Y; r y is the relative wind speed; a0, a1...a4 are the aerodynamic drag coefficients, which are functions of the deviation angle; Y is the surface wind speed deviation angle relative to the vehicle's direction of travel; m is the vehicle mass; This refers to the road slope.

[0190] In one embodiment, the expression for the wheel-side torque of the drive wheel constructed by the second construction module 40 is:

[0191] F wheel =F gear +F axle +μ*m i *g*cosθ i

[0192] +F ini +m i *g*cotθ i

[0193] Among them, F wheel F is the wheel-side torque of the drive wheel. gear This refers to the torque loss in neutral gear at the corresponding speed of the transmission; F axle The torque loss in neutral at the corresponding speed of the drive axle; μ is the rolling resistance coefficient of the entire vehicle; m i For the axle load of the drive wheel position; θ i F represents the slope value at each location; ini The internal resistance of the drive shaft.

[0194] In one embodiment, the expression for the vehicle's mechanical resistance constructed by the third building module 50 is:

[0195]

[0196] Among them, F mesh For the mechanical resistance of the entire vehicle; V is the fitting constant term in the expression for the vehicle's running resistance; V is the measured vehicle speed; A m B is the mechanical resistance coefficient for the zero-order term. m C is the coefficient of mechanical resistance for the first-order term; m θ is the mechanical drag coefficient of the second term; m is the vehicle mass; μ is the rolling resistance coefficient of the whole vehicle; θ i F represents the slope value at each location; gear This refers to the torque loss in neutral gear at the corresponding speed of the transmission; F axle This refers to the torque loss in neutral at the corresponding speed of the drive axle. For road slope; F in The internal resistance of the target vehicle.

[0197] Each module in the aforementioned vehicle driving resistance measurement device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the memory of a computer device as software, so that the processor can call and execute the corresponding operations of each module.

[0198] In one embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 7As shown, the computer device includes a processor, memory, input / output interface, communication interface, display unit, and input device. The processor, memory, and input / output interface are connected via a system bus, and the communication interface, display unit, and input device are also connected to the system bus via the input / output interface. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The input / output interface is used for exchanging information between the processor and external devices. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, mobile cellular networks, NFC (Near Field Communication), or other technologies. When the computer program is executed by the processor, it implements a method for measuring the driving resistance of a vehicle. The display unit is used to form a visually visible image and can be a display screen, a projection device, or a virtual reality imaging device. The display screen can be an LCD screen or an e-ink screen. The input device of the computer device can be a touch layer covering the display screen, or buttons, trackballs, or touchpads set on the casing of the computer device, or external keyboards, touchpads, or mice, etc.

[0199] Those skilled in the art will understand that Figure 7 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0200] In one embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the above-described method embodiments.

[0201] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the steps in the above method embodiments.

[0202] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above method embodiments.

[0203] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0204] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0205] The above embodiments are merely illustrative of several implementation methods of this application, and their descriptions are relatively specific and detailed. However, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for measuring the driving resistance of a vehicle, characterized in that, The method includes: Construct an expression for the overall vehicle driving resistance; the overall vehicle driving resistance in the expression consists of mechanical resistance, aerodynamic resistance, and gradient resistance; Acquire measurement data of the target vehicle during a coasting test, and determine the value of the aerodynamic drag based on the measurement data; Substituting the aerodynamic drag value into the vehicle drag expression, we obtain the target vehicle drag expression. Construct an expression for the wheel-side torque of the drive wheel; the wheel-side torque in the expression includes a first torque and a second torque; the first torque includes the transmission neutral torque loss and the drive axle neutral torque loss, and the second torque includes the drive shaft rolling resistance, the drive shaft internal resistance, and the slope resistance; Construct an expression for the mechanical resistance of the entire vehicle; the mechanical resistance of the entire vehicle in the expression includes a first mechanical resistance and a second mechanical resistance; the first mechanical resistance includes transmission loss and drive axle loss, and the second mechanical resistance includes the rolling resistance of the target vehicle, the internal resistance of the target vehicle, and the gradient resistance; The axle load of the drive wheel is obtained, and based on the measurement data, the equivalent mass of the drive wheel and the equivalent mass of the target vehicle are determined. Based on the axle load of the drive wheel, the equivalent mass of the drive wheel, and the equivalent mass of the target vehicle, the proportional relationship between the second torque and the second mechanical resistance is determined; After removing the torque loss in neutral gear of the transmission and the torque loss in neutral gear of the drive axle, based on the proportional relationship, the second torque is expressed as an expression related to the second mechanical resistance, and the expression for the overall vehicle mechanical resistance is updated. Based on the value of the wheel-side torque, the updated expression for the vehicle's mechanical resistance is solved to obtain the value of the second mechanical resistance. Without removing the torque loss in neutral gear of the transmission and the torque loss in neutral gear of the drive axle, the value of the target slope is obtained based on the value of the second mechanical resistance and the expression of the target vehicle driving resistance. Substitute the value of the target slope into the expression for the vehicle's driving resistance to obtain the value of the vehicle's drag coefficient. Substitute the value of the target slope into the expression for the vehicle's mechanical resistance to obtain the value of the vehicle's rolling resistance coefficient. The value of the vehicle's drag coefficient and rolling resistance coefficient are used to determine the value of the vehicle's driving resistance.

2. The method according to claim 1, characterized in that, The aerodynamic drag includes frontal wind speed drag and lateral wind speed drag; the measurement data includes frontal wind speed, the equivalent mass of the target vehicle, and the vehicle speed of the target vehicle; determining the value of the aerodynamic drag based on the measurement data includes: The forward wind speed is corrected to obtain the corrected forward wind speed, and the forward wind speed drag value is obtained by fitting based on the corrected forward wind speed. Based on the equivalent mass of the target vehicle and the vehicle speed, the value of the lateral wind speed drag is obtained by fitting. The value of the aerodynamic drag is determined based on the values ​​of the forward wind speed drag and the lateral wind speed drag.

3. The method according to claim 1, characterized in that, The step of calculating the target slope value based on the value of the second mechanical resistance and the expression for the target vehicle driving resistance, without removing the neutral torque loss of the transmission and the drive axle, includes: Without removing the neutral torque loss of the transmission and the neutral torque loss of the drive axle, obtain the coasting data of the target vehicle during the coasting test, as well as the measured value of the first mechanical resistance. Based on the aforementioned gliding data, the value of the vehicle's mechanical resistance is obtained through fitting. Substitute the values ​​of the vehicle's mechanical resistance, the first mechanical resistance, and the second mechanical resistance into the expression for the target vehicle's driving resistance to obtain the target slope value.

4. The method according to claim 1, characterized in that, The step of substituting the value of the target slope into the expression for the mechanical resistance of the entire vehicle to obtain the value of the rolling resistance coefficient of the entire vehicle includes: Substituting the value of the target slope into the expression for the mechanical resistance of the whole vehicle, we obtain the sum of the values ​​of the rolling resistance of the target vehicle and the internal resistance of the target vehicle. Set the value of the internal resistance of the target vehicle to zero, and calculate the value of the rolling resistance of the target vehicle based on the sum of the values. Based on the value of the rolling resistance of the target vehicle, the value of the rolling resistance coefficient of the whole vehicle is obtained.

5. The method according to claim 1, characterized in that, The constructed expression for the vehicle's driving resistance is as follows: in, The equivalent mass of the target vehicle; To measure vehicle speed; The frontal area of ​​the vehicle; The mechanical resistance coefficient is the zero-order term. The mechanical resistance coefficient for the first-order term; This is the mechanical resistance coefficient for the second term; air density; The drag coefficient of the vehicle at the deviation angle Y; Relative wind speed; is the aerodynamic drag coefficient, a function of the deviation angle; Y is the surface wind speed deviation angle relative to the vehicle's direction of travel; m is the vehicle's mass; This refers to the road slope.

6. The method according to claim 1, characterized in that, The expression for the wheel-side torque of the constructed drive wheel is: in, This refers to the torque at the wheel edge of the drive wheel; This refers to the torque loss in neutral gear at the corresponding speed of the transmission. This refers to the torque loss in neutral at the corresponding speed of the drive axle. This is the rolling resistance coefficient of the entire vehicle; For the axle load of the drive wheel position; These are the slope values ​​at each location; The internal resistance of the drive shaft is given.

7. The method according to claim 1, characterized in that, The constructed expression for the vehicle's mechanical resistance is as follows: in, This refers to the mechanical resistance of the entire vehicle. This is the fitting constant term in the expression for the vehicle's driving resistance. To measure vehicle speed; The mechanical resistance coefficient is the zero-order term. The mechanical resistance coefficient for the first-order term; The mechanical resistance coefficient is the second-order term; m is the vehicle mass. This is the rolling resistance coefficient of the entire vehicle; These are the slope values ​​at each location; This refers to the torque loss in neutral gear at the corresponding speed of the transmission. This refers to the torque loss in neutral at the corresponding speed of the drive axle. Road slope; The internal resistance of the target vehicle.

8. A device for measuring the driving resistance of a vehicle, characterized in that, The device includes: The first construction module is used to construct the vehicle driving resistance expression; the vehicle driving resistance in the vehicle driving resistance expression consists of mechanical resistance, aerodynamic resistance and gradient resistance; The data acquisition module is used to acquire measurement data of the target vehicle during a coasting test, and to determine the value of the aerodynamic drag based on the measurement data; The expression acquisition module is used to substitute the value of the aerodynamic drag into the vehicle driving drag expression to obtain the target vehicle driving drag expression; The second construction module is used to construct the wheel-side torque expression of the drive wheel; the wheel-side torque in the wheel-side torque expression includes a first torque and a second torque; the first torque includes the transmission neutral torque loss and the drive axle neutral torque loss, and the second torque includes the drive shaft rolling resistance, the drive shaft internal resistance and the slope resistance; The third construction module is used to construct the vehicle mechanical resistance expression; the vehicle mechanical resistance in the vehicle mechanical resistance expression includes a first mechanical resistance and a second mechanical resistance; the first mechanical resistance includes transmission loss and drive axle loss, and the second mechanical resistance includes target vehicle rolling resistance, target vehicle internal resistance, and gradient resistance; The first solution module is used to obtain the axle load of the drive wheel, and based on the measurement data, determine the equivalent mass of the drive wheel and the equivalent mass of the target vehicle; based on the axle load of the drive wheel, the equivalent mass of the drive wheel, and the equivalent mass of the target vehicle, determine the proportional relationship between the second torque and the second mechanical resistance; after removing the neutral torque loss of the transmission and the neutral torque loss of the drive axle, based on the proportional relationship, express the second torque as an expression related to the second mechanical resistance, and update the expression of the overall vehicle mechanical resistance; based on the value of the wheel-side torque, solve the updated expression of the overall vehicle mechanical resistance to obtain the value of the second mechanical resistance; The second solving module is used to solve for the value of the target slope based on the value of the second mechanical resistance and the expression of the target vehicle driving resistance without removing the torque loss in neutral gear of the transmission and the torque loss in neutral gear of the drive axle. The third solution module is used to substitute the value of the target slope into the expression for the vehicle's driving resistance to obtain the value of the vehicle's wind resistance coefficient, and to substitute the value of the target slope into the expression for the vehicle's mechanical resistance to obtain the value of the vehicle's rolling resistance coefficient. The numerical determination module is used to determine the value of the vehicle's driving resistance based on the value of the vehicle's drag coefficient and the value of the vehicle's rolling resistance coefficient.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 7.

11. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 7.

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