A whole vehicle road load bench test device and method

Abstract

The application relates to a whole vehicle road load bench test device and method, which is characterized in that a driving axle fixing tool and a control system are additionally arranged on a tire drum tester; a vertical loading system for applying actual load during whole vehicle test is arranged on the driving axle fixing tool; when in use, a driving axle body with wheels, a power system, a transmission, a transmission shaft, a temperature adjusting system and a transmission control system are assembled to form a sample to be tested; the driving axle body of the sample to be tested is connected with the driving axle fixing tool, so that the wheels are in contact with a roller of a dynamometer; the control system controls the sample to be tested and the vertical loading system to operate by using input sample parameters and road spectrum information; the loading device of the tire drum tester is controlled according to the rotating speed of the roller of the dynamometer and a compensated bench running resistance curve, and the running resistance is adjusted, so that the bench test is consistent with the actual situation, and the test result is accurate; only key vehicle components are provided, so that the vehicle development cycle is shortened, and the cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bench simulation experiment, in particular to a vehicle road load bench test device and method. BACKGROUND

[0002] At present, vehicle road durability test is a necessary test in vehicle development verification, and vehicle road load durability test has a long cycle and is greatly affected by weather. The fixed expenses such as site fee, driver cost, fuel cost and travel cost are very high, resulting in high test cost. Therefore, current automobile companies are exploring how to carry out virtual verification and bench verification to reduce road verification as much as possible to reduce development cost.

[0003] In some related technologies, parts bench simulation load durability test is used, but there is a problem of insufficient test result reliability, and the reason is that:

[0004] (1) In the test process, the tire is directly disassembled, and the wheel shaft is connected with the dynamometer, which does not consider the influence of the driving resistance of the tire in the actual vehicle road load test.

[0005] (2) In the actual test process of the vehicle, the road load changes and fluctuates with the vehicle load and speed, and the driving resistance of the tire at each moment is different. When the parts bench simulation is used, the vehicle is in a fixed state, and the influence of the transient driving resistance caused by frequent working conditions is not considered, which finally leads to insufficient test result reliability. SUMMARY

[0006] The embodiments of the present application provide a vehicle road load bench test device and method to solve the problem of insufficient test result reliability in the related art bench simulation test for vehicle road load, which does not consider the influence of the driving resistance of the tire in the actual vehicle road load test.

[0007] In a first aspect, a vehicle road load bench test device is provided, which includes a tire drum test machine, a drive axle fixing tool and a control system connected to the tire drum test machine; the drive axle fixing tool is provided with a vertical loading system;

[0008] The control system is used to control the vertical loading system to simulate the actual load during vehicle test; the control system is also used to detect the rotating speed of the dynamometer roller of the tire drum test machine, and control the loading device of the tire drum test machine to adjust the driving resistance in time according to the compensated bench driving resistance curve and the rotating speed.

[0009] In some embodiments, the drive axle fixing tool includes a connecting seat, and the connecting seat is provided with a mounting channel for the drive axle body to pass through; the outer side of the connecting seat is provided with a support arm connected with the tire drum test machine;

[0010] The vertical loading system comprises a hydraulic cylinder, the telescopic end of which extends into the installation channel and abuts against the drive axle body.

[0011] The second aspect provides a vehicle road load bench test method, comprising the following steps:

[0012] A vehicle road load bench test device is provided;

[0013] A drive axle body with wheels at both ends, a power system, a transmission, a drive shaft, a temperature regulation system and a transmission control system are assembled to form a sample to be tested; then the drive axle body of the sample to be tested is connected with the drive axle fixing tool to make the wheels contact with the roller of the dynamometer;

[0014] The sample parameters and road spectrum information collected in the actual vehicle road load test are used as control data; the control data and the control system are used to control the operation of the sample to be tested and the vertical loading system; then the loading device of the tire drum tester is adjusted in time to control the rolling resistance according to the speed of the roller of the dynamometer and the compensated bench rolling resistance curve.

[0015] In some embodiments, the sample parameters include engine inertia, engine idle speed, engine universal characteristic MAP, vehicle test mass, main reduction ratio, transmission speed ratio, wheel rolling radius, brake torque;

[0016] The road spectrum information includes vehicle speed, gear position and driving distance, engine speed, throttle, output torque, drive shaft output torque, actual load, actual vehicle road rolling resistance curve in the actual vehicle road load test.

[0017] In some embodiments, the compensated bench rolling resistance curve is obtained, specifically comprising the following steps:

[0018] The actual vehicle road rolling resistance curve obtained through the road sliding test is used as the reference rolling resistance curve;

[0019] The vehicle road load bench test device is tested for internal resistance sliding to obtain a bench internal resistance curve;

[0020] The sample to be tested is installed on the vehicle road load bench test device for sliding test to obtain a bench rolling resistance curve of the sample to be tested;

[0021] According to the reference rolling resistance curve, the bench rolling resistance curve and the bench internal resistance curve, the bench rolling resistance corresponding to each vehicle speed is compensated to obtain a compensated bench rolling resistance curve.

[0022] In some embodiments, the vehicle road load bench test device is subjected to an internal resistance coasting test to obtain a bench internal resistance curve, including the following steps:

[0023] The motor-driven dynamometer roller of the tire drum tester is operated to a set speed.

[0024] The power input of the motor of the dynamometer is cut off, so that the dynamometer roller overcomes the internal resistance by inertia to do coasting motion.

[0025] The time from deceleration to zero speed and the total coasting distance are recorded.

[0026] The upper and lower error limit values of a certain vehicle speed and the time corresponding to the upper error limit value coasting to the lower error limit value of the certain vehicle speed are obtained during the process of decelerating from the set speed to zero; and the corresponding coasting distance is calculated according to the upper and lower error limit values and the time.

[0027] Then, according to the kinetic energy theorem and the upper and lower error limit values and the coasting distance, the bench internal resistance value corresponding to the certain vehicle speed is calculated.

[0028] The above steps are repeated to obtain the bench internal resistance values corresponding to multiple vehicle speeds to fit the bench internal resistance curve.

[0029] In some embodiments, the sample to be tested is installed on the vehicle road load bench test device to perform a coasting test to obtain a bench driving resistance curve of the sample to be tested, including the following steps:

[0030] The power system and transmission of the sample to be tested are controlled by the control system to drive the wheels to rotate to a set maximum speed.

[0031] The power input of the transmission to the drive shaft is cut off to make the wheels do coasting motion.

[0032] The time from deceleration to zero speed and the rotational speed at each time are recorded.

[0033] The time difference and speed difference corresponding to the upper error limit value of a certain vehicle speed coasting to the lower error limit value of the certain vehicle speed during the process of decelerating from the set speed to zero are calculated, and then the bench driving resistance corresponding to the certain vehicle speed is calculated according to Newton's second law.

[0034] The above steps are repeated to obtain the bench driving resistances corresponding to multiple vehicle speeds to fit the bench driving resistance curve.

[0035] In some embodiments, the bench driving resistance corresponding to each vehicle speed is compensated according to the reference driving resistance curve, the bench driving resistance curve and the bench internal resistance curve to obtain a compensated bench driving resistance curve, including the following steps:

[0036] obtaining a standard resistance corresponding to the reference running resistance curve, a bench running resistance corresponding to the bench running resistance curve and a bench internal resistance value corresponding to the bench internal resistance curve at the same vehicle speed;

[0037] obtaining a middle value by subtracting the bench internal resistance value corresponding to the bench internal resistance curve from the bench running resistance corresponding to the bench running resistance curve at the same vehicle speed; and comparing the middle value with the standard resistance value corresponding to the reference running resistance curve;

[0038] if the error between the middle value and the standard resistance value corresponding to the reference running resistance curve is less than the design error range, the bench running resistance corresponding to the bench running resistance curve at the vehicle speed meets the requirements; otherwise, the bench running resistance corresponding to the bench running resistance curve at the vehicle speed is compensated;

[0039] repeating the above steps to optimize the bench running resistance corresponding to each vehicle speed of the bench running resistance curve to obtain a compensation curve.

[0040] In some embodiments, the step of compensating the bench running resistance corresponding to the bench running resistance curve at the vehicle speed comprises the following steps:

[0041] obtaining a compensation value by subtracting the standard resistance value corresponding to the reference running resistance curve from the middle value;

[0042] adding the compensation value to the bench running resistance corresponding to the vehicle speed to obtain a new bench running resistance corresponding to the vehicle speed.

[0043] In some embodiments, after the control data and the control system are used to control the operation of the sample and the vertical loading system, the loading device of the tire test machine is adjusted in time according to the compensated bench running resistance and the rotational speed of the dynamometer roller to adjust the running resistance, and the method further comprises the following steps:

[0044] determining whether the power system and the temperature adjusting system are preheated to the same temperature and pressure as the actual vehicle road load test;

[0045] if yes, the step of adjusting the running resistance of the tire test machine in time according to the compensated bench running resistance curve and the loading device of the tire test machine is performed;

[0046] otherwise, the preheating is continued.

[0047] The technical scheme provided by the present application has the following beneficial effects:

[0048] The embodiment of the application provides a whole vehicle road load bench test device and method, wherein a driving axle fixing tool and a control system are additionally arranged on a tire drum tester; the driving axle fixing tool is provided with a vertical loading system for applying actual load in whole vehicle test; in use, the driving axle body, a power system, a transmission, a transmission shaft, a temperature adjusting system and a transmission control system are assembled to form a sample to be tested, then the driving axle body of the sample to be tested is connected with the driving axle fixing tool, so that the wheel is in contact with the roller of the dynamometer; the control system controls the sample to be tested and the vertical loading system to operate by using control data; then the loading device of the tire drum tester is controlled to adjust the running resistance instantaneously according to the speed of the roller of the dynamometer and the compensated bench running resistance curve, so that the bench test is consistent with the actual situation in the transient change at different speeds, and the test result is accurate; in addition, the whole vehicle does not need to be tested, only the key vehicle parts need to be provided, the test can be carried out without the sample vehicle after the sample is trial-produced before the design scheme is finalized, then the vehicle design scheme is adjusted in time according to the test result, the performance of the whole vehicle is optimized, the vehicle development cycle is shortened, and the development cost is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0049] In order to more clearly illustrate the technical solutions in the embodiments of the application, the drawings needed to be used in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative effort.

[0050] Fig. 1 A state schematic view of the whole vehicle road load bench test device provided by the embodiment of the application is installed with a sample to be tested.

[0051] Fig. 2 A flowchart of the whole vehicle road load bench test method provided by the embodiment of the application.

[0052] In the figure: 1, tire drum tester; 2, driving axle fixing tool; 200, connecting seat; 201, supporting arm; 3, vertical loading system; 4, roller of dynamometer; 5, wheel; 6, driving axle body; 7, power system; 8, transmission; 9, transmission shaft; 10, temperature adjusting system; 11, transmission control system. DETAILED DESCRIPTION

[0053] To make the purposes, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0054] The main components of a general tire drum tester include:

[0055] Frame: welded by section steel, which serves as a support, and all components are installed on the frame. Drum: rolled by steel plate, which is placed on the support through two end support half shafts and a vertical seat bearing, forming a free rotating cylinder. The cylinder is provided with a material opening that can be opened or closed and sealed, and a lifting plate is welded in the cylinder. Driving device: composed of a reducer motor, a shaft coupling, etc., which drives the drum to rotate at a constant speed required, and the reducer system is also provided with a manual adjustment device for facilitating unloading. Counting device: connected with the end support half shaft of the drum, which can feedback the rotating speed and record the rotating number, and the device is automatically stopped when the required number of revolutions is reached. Loading device: providing resistance torque to simulate the driving resistance. Measuring device: measuring torque and rotating speed, which usually includes a force lever type and a flywheel mechanism, etc.

[0056] For the present application, the greater the road load, the more fuel consumed, and the road load diagram highlights the power demand in a certain driving speed range in a stable running state, and uses a component bench to simulate load endurance test, but there is a problem of insufficient reliability of test results, the reason is that:

[0057] (1) In the test process, the tire is directly disassembled, and the wheel shaft is connected with the dynamometer, which does not consider the influence of the driving resistance of the tire in the actual vehicle road load test.

[0058] (2) In the actual test process of the vehicle, the road load changes and fluctuates with the vehicle load and speed, and the driving resistance of the tire at each moment is different, and when the component bench is simulated, the vehicle is in a fixed state, and the influence of the transient driving resistance caused by frequent changes in working conditions is not considered, which ultimately leads to insufficient reliability of test results

[0059] The embodiments of the present application provide a vehicle road load bench test device and method, to solve the problem that the bench simulation test for the vehicle road load in the related art does not consider the influence of the driving resistance of the tire in the actual vehicle road load test, resulting in insufficient reliability of test results.

[0060] In the first aspect, please refer to Figs. 1-2, first put forward a kind of whole vehicle road load bench test device, including tire drum tester 1;Tire drum tester 1 is connected with drive axle fixed tooling 2 and control system;Drive axle fixed tooling 2 is equipped with vertical loading system 3;Control system is used to simulate the actual load applied by vertical loading system 3 during whole vehicle test;The control system is also used to detect the rotational speed of the dynamometer roller 4 of the tire drum tester 1, the dynamometer roller 4 is in contact with the wheel 5, and then the rotational speed and the compensated bench driving resistance curve are used to control the loading device of the tire drum tester 1 to adjust the driving resistance instantaneously (in time).

[0061] Drive axle fixed tooling 2 includes connecting seat 200, connecting seat 200 is equipped with mounting channel for drive axle body 6 to pass through;The outer side of connecting seat 200 is provided with support arm 201 connected with tire drum tester 1;Vertical loading system 3 includes hydraulic cylinder, the telescopic end of hydraulic cylinder extends into mounting channel and abuts with drive axle body 6.The above only gives a specific structure of drive axle fixed tooling 2 vertical loading system 3, including but not limited to other forms, as long as the function of linearly connecting and fixing drive axle body 6, the function of applying actual load during whole vehicle test can be applied.

[0062] The above is based on tire drum tester 1, which is added to simulate the actual load during whole vehicle test, and the driving resistance in the actual whole vehicle road load test is simulated by the compensated bench driving resistance curve and the rotational speed of the wheel 5.

[0063] In use, the drive axle body 6 with the wheel 5, the power system 7, the transmission 8, the transmission shaft 9, the temperature adjusting system 10 and the transmission control system 11 are assembled to form the sample to be tested, then the drive axle body 6 of the sample to be tested is connected with the drive axle fixed tooling 2, so that the wheel 5 is in contact with the dynamometer roller 4;The control system controls the operation of the sample to be tested and the vertical loading system 3 by using control data;Then the rotational speed of the dynamometer roller 4 and the compensated bench driving resistance curve are used to control the loading device of the tire drum tester 1 to adjust the driving resistance in time, so that the bench test conforms to the actual situation under different vehicle speeds, so as to ensure the accuracy of the test results;In addition, the whole vehicle does not need to be tested, only the key vehicle parts need to be provided, the test can be carried out without sample vehicle before the design scheme is finalized and after the sample is manufactured, then the vehicle design scheme is adjusted in time according to the test results, the performance of the whole vehicle is optimized, the vehicle development cycle is shortened, and the development cost is reduced.

[0064] The second aspect is a whole vehicle road load bench test method, comprising the following steps:

[0065] Step 100, providing a whole vehicle road load bench test device;

[0066] Step 200, the driving axle body 6 with wheels 5 at both ends of the whole vehicle, power system 7, transmission 8, transmission shaft 9, temperature regulation system 10 and transmission control system 11 are assembled to form a sample to be tested; then the driving axle body 6 of the sample to be tested is connected with the driving axle fixing tool 2 to make the wheels 5 contact with the dynamometer roller 4;

[0067] Step 300, the sample parameters and road spectrum information collected by the actual whole vehicle road load test are used as control data; the control data and the control system are used to control the operation of the sample to be tested and the vertical loading system 3; then the loading device of the tire test machine 1 is controlled according to the speed of the dynamometer roller 4 and the compensated bench running resistance curve to adjust the running resistance instantaneously.

[0068] The control system controls the loading device of the tire test machine 1, converts the collected speed to obtain the vehicle speed and acceleration, combines the control data input into the control system before and the compensated bench running resistance curve to obtain the total running resistance at this moment, and then converts it into torque to be applied to the wheels by the loading device. Since the tire speed and torque are changing in real time, the action is repeated continuously, so that the whole vehicle road load bench test device dynamically simulates the running resistance to the wheels 5.

[0069] The control system is responsible for collecting the speed, rotation speed, throttle, torque, temperature, pressure, opening degree, position coordinates, displacement, stress and force signals of each system, and storing them in real time. The control system integrates automobile running simulation software, can control the tested system according to the written automatic sequence, and can take measures to protect the test equipment and sample when the value of a certain parameter collected exceeds the limit value according to the preset parameter limit value and instruction. In order to ensure the transmission efficiency and consistency with the actual vehicle, the installation position and angle of each part of the sample to be tested need to be adjusted to be consistent with the actual vehicle; the transmission control system 11 is a fast response gear shifting robot; the gear shifting logic is a control logic for confirming the timing of entering different gears according to the real-time vehicle speed; the gear shifting logic is used to judge when to start upshift or downshift; for downshift, in addition to the conventional gear-by-gear shifting logic, it is also necessary to ensure consistency with the driver's operation habit in special scenarios, that is, if the last cycle needs to stop from a high speed, the driver usually uses the method of directly stepping on the clutch and braking to achieve the purpose, so the gear shifting strategy in this scenario also needs to be consistent with the driver's habit, otherwise the damage in the brake stage will differ by thousands of times. Therefore, the selection of multiple gear shifting strategies not only needs to be judged according to the vehicle speed, but also needs to be judged in combination with the automatic sequence simulating the driver's operation habit.

[0070] The above sample parameters include engine inertia, engine idle speed, engine universal characteristic MAP, whole vehicle test mass, main reduction ratio, transmission speed ratio, wheel rolling radius, brake torque;

[0071] The road spectrum information includes vehicle speed, gear position, and driving distance, engine speed, throttle, output torque, drive shaft output torque, actual load, and actual road driving resistance curve of the vehicle during the actual vehicle road load test.

[0072] In some preferred embodiments, how to obtain the compensated bench driving resistance curve is described in detail, which specifically includes the following steps:

[0073] Step 300-1: The actual road driving resistance curve of the vehicle obtained through the road sliding test is taken as the reference driving resistance curve; wherein obtaining the reference driving resistance curve includes the following steps: performing vehicle preparation and actual road sliding test according to the requirements of Appendix CD of GB 18352.6-2016 Light-duty Vehicle Emission Limit Values and Measurement Methods (China Phase VI), obtaining the sliding data of the test vehicle on the actual road, calculating the road driving resistance at each speed, i.e. the standard resistance value F 道路i , and deriving the road sliding curve F0=A0+B0*V+C0*V 2 .

[0074] Step 300-2: Internal resistance sliding test is performed on the vehicle road load bench test device to obtain the bench internal resistance curve; step 300-2 specifically includes:

[0075] The motor of the dynamometer of the tire drum tester 1 is driven to run the dynamometer drum 4 to the set maximum speed;

[0076] The power input of the motor of the dynamometer is cut off to make the dynamometer drum 4 slide with its own inertia to overcome the internal resistance;

[0077] The time taken from deceleration to zero speed and the total sliding distance are recorded;

[0078] The upper and lower error values of a certain speed and the time corresponding to the sliding of the upper error value to the lower error value of the certain speed are obtained during the process of decelerating from the set speed to zero; the corresponding sliding distance L is calculated according to the upper and lower error values and the time; then the bench internal resistance value corresponding to the certain speed is calculated according to the kinetic energy theorem; the lower error value of a certain speed is V i -5km, i.e. v1; the upper error value of a certain speed is V i +5km, i.e. v2; m is the mass of the vehicle; according to the kinetic energy theorem FL=1 / 2mv2 2 -1 / 2mv1 2 , the resistance F i of a certain speed V ri。 is calculated.

[0079] Repeat the above steps to obtain a plurality of vehicle speed corresponding to the bench resistance value, to fit the bench resistance curve; namely F r =A r +B r *V+C r *V 2 .

[0080] Step 300-3, the measured sample is installed on the whole vehicle road load bench test device for sliding test, to obtain the bench driving resistance curve of the measured sample; step 300-3, specifically comprising:

[0081] The power system 7 and the transmission 8 of the measured sample are controlled by the control system, so that the transmission shaft 9 drives the wheels 5 to rotate to the set highest speed;

[0082] The power input of the transmission 8 to the transmission shaft 9 is cut off, so that the wheels 5 do sliding motion;

[0083] The time used and the speed at each time during the process of the wheels 5 from deceleration to zero speed are recorded;

[0084] The time difference Δt and the speed difference ΔV from the error upper limit value Vi+5km / h of a certain speed to the error lower limit value Vi-5km / h of the certain speed in the process of the highest speed decelerating to zero are calculated; then the corresponding bench driving resistance of a certain speed is calculated by combining Newton's second law F=ma=m*ΔV / Δt, wherein m is the mass of the whole vehicle, and the bench driving resistance F corresponding to the vehicle speed Vi is calculated 实际i .

[0085] Repeat the above steps to obtain a plurality of vehicle speed corresponding to the bench resistance value, to fit the bench resistance curve; namely F

[0086] Step 300-4, according to the reference driving resistance curve, the bench driving resistance curve and the bench resistance curve, the bench driving resistance corresponding to each vehicle speed is compensated to obtain the compensated bench driving resistance curve; step 300-4, specifically comprising: obtaining the standard resistance corresponding to the reference driving resistance curve, the bench driving resistance corresponding to the bench driving resistance curve and the bench resistance value corresponding to the bench resistance curve at the same vehicle speed;

[0087] The bench driving resistance corresponding to the bench driving resistance curve and the bench resistance value corresponding to the bench resistance curve at the same vehicle speed are subtracted to obtain an intermediate value; then the intermediate value is compared with the standard resistance value corresponding to the reference driving resistance curve to determine;

[0088] If the error between the intermediate value and the standard resistance value corresponding to the reference running resistance curve is less than the design error range, the bench running resistance corresponding to the vehicle speed in the bench running resistance curve meets the requirements; otherwise, the bench running resistance corresponding to the vehicle speed in the bench running resistance curve is compensated.

[0089] The above steps are repeated to optimize the bench running resistance corresponding to each vehicle speed of the bench running resistance curve to obtain a compensation curve.

[0090] Since the bench has an internal resistance F ri , although theoretically F 实际i -F ri =F 道路i , in fact, due to the great difference between the bench and the road, F 实际i -F ri ≠F 道路i .

[0091] F 实际i is the bench running resistance, F 道路i is the standard resistance value, and F ri is the bench internal resistance value.

[0092] The running resistance on the bench (F 实际i -F ri ) and the standard resistance value F 道路i at the same vehicle speed are compared, and if the deviation between them is within ±10N, it is considered that the bench rolling resistance meets the requirements; if the deviation is greater than ±10N, the bench rolling resistance needs to be compensated, and the resistance F 补偿i that needs to be compensated for each vehicle speed is F 实际i -F ri -F 道路i , then the new bench running resistance F ri ’=F ri +F 补偿i , the updated bench running resistance and the corresponding vehicle speed are fitted to obtain a new bench running resistance curve and the coefficient

[0093] The above steps are repeated to optimize the bench running resistance corresponding to each vehicle speed of the bench running resistance curve to obtain a compensation curve.

[0094] In some preferred embodiments, after the test sample and the vertical loading system 3 are controlled to operate by using the control data and the control system; the loading device of the tire drum test machine 1 is controlled to adjust the running resistance instantaneously according to the compensated bench running resistance curve and the rotational speed of the wheel 5, further comprising the following steps:

[0095] It is judged whether the power system 7 and the temperature adjusting system 10 are preheated to reach the same temperature and pressure as the actual vehicle road load test.

[0096] If reached, then the step of adjusting the running resistance of the tire test machine 1 in time according to the compensated running resistance curve of the test bench and the loading device is performed.

[0097] If not, the preheating continues.

[0098] In some preferred embodiments, how to meet the test conditions that accurately match the actual whole vehicle road is described above, and the subsequent process of the test is described below:

[0099] In the test process simulated by the whole vehicle road load test bench test device, the automatic sequence is continuously run for no less than 3 cycles, and relevant information during running is collected; the fatigue analysis software is used to calculate the damage degree of the system in each cycle, invalid data is removed, the average value D1 of the multiple results is taken, the test bench parameters and the automatic sequence are repeatedly adjusted, and until D1≈D0; if it is necessary to speed up the examination, a strengthening coefficient n needs to be calculated, relevant parameters are optimized, and until D1≈n*D0; according to the given strengthening coefficient n, the test cycle number or test time is calculated according to the adjusted automatic sequence and the test mileage, the total damage Dt1 of the test bench test is calculated, and the test bench test is carried out; if the main examination part appears damage during the test process, the test is stopped, the test cycle number and test mileage and the like information at this time are recorded, and the failure reason of the sample part is analyzed; if part of the tested parts of the non-main examination part appears failure or damage during the test process, the test bench is stopped, and the relevant situation of the failure is recorded, after the failure reason is investigated and solved, the test can continue until the test is completed; the collected data is checked every day, and the consistency and accuracy of the test data are ensured; after the test bench test is completed, the examination sample is subjected to appearance inspection, function inspection, disassembly analysis and the like; the data recorded by the control system is sorted and analyzed, the test sample inspection and analysis after the test, the problems and failure parts during the test process and the like are combined, and the performance of each part of the transmission system is analyzed according to the data recorded by the control system, and the test report is prepared.

[0100] The beneficial effects of the present application are as follows:

[0101] Firstly, in the present application, the engine or driving motor drives the wheels, the resistance is provided by the vertical loading system and the loading device of the tire test machine 1, and the dynamometer roller 4 of the tire test machine 1 simulates the transmission pair of the whole vehicle wheel and the ground, so that different working conditions on the test bench are simulated. The test method can carry out the test without a sample vehicle even without a driving system before the design scheme is finalized and after the sample is trial-produced, the design scheme of the vehicle type is adjusted in time according to the test result, the performance of the whole vehicle is optimized, the development cycle of the vehicle type is shortened, and the development cost is reduced.

[0102] Secondly, the application solves the problem that the traditional component bench cannot slide, ensures the consistency of the bench running resistance and the actual road running resistance of the whole vehicle, and improves the precision of the variable working condition and uniform speed working condition test.

[0103] Thirdly, the application can adjust specific test conditions for testing, and compared with uncontrollable factors such as the change of the whole vehicle road test environment and personnel operation, the bench test has better consistency, and the test result is more accurate.

[0104] In the description of the present application, it should be noted that the positions or position relationships indicated by the terms "upper", "lower", etc. are based on the positions or position relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. Unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through an intermediate medium, or internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0105] It should be noted that in the present application, relationship terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations. Moreover, the terms "include", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the sentence "including a" does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0106] The above is only a specific embodiment of the present application, which enables those skilled in the art to understand or implement the present application. Various modifications of these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features applied herein.

Claims

1. A vehicle road load bench test method, characterized in that: It includes the following steps: A whole vehicle road load bench test device is provided; the whole vehicle road load bench test device comprises a tire drum tester (1), the tire drum tester (1) is connected to a drive axle fixing fixture (2) and a control system; the drive axle fixing fixture (2) is provided with a vertical loading system (3); the control system is used to control the vertical loading system (3) to simulate the actual load during the whole vehicle test; the control system is also used to detect the rotation speed of a dynamometer roller (4) of the tire drum tester (1), and to control the loading device of the tire drum tester (1) to adjust the running resistance in real time according to a compensated bench running resistance curve and the rotation speed; Assembling a drive axle body (6) with wheels (5) at both ends of a vehicle, a power system (7), a transmission (8), a drive shaft (9), a temperature control system (10), and a transmission control system (11) to form a sample to be tested; then connecting the drive axle body (6) of the sample to be tested to the drive axle fixing fixture (2) so that the wheels (5) are in contact with the dynamometer roller (4); The sample parameters and road spectrum information collected during the actual vehicle road load test are used as control data; the control data and the control system are used to control the operation of the sample to be tested and the vertical loading system (3); then, the loading device of the tire drum tester (1) is controlled to adjust the driving resistance in real time according to the rotation speed of the dynamometer roller (4) and the compensated bench driving resistance curve; the sample parameters include engine inertia, engine idle speed, engine universal characteristic MAP, vehicle test mass, main reduction ratio, gear ratio, wheel rolling radius and braking torque; the road spectrum information includes vehicle speed, gear position and driving distance, engine speed, throttle, output torque, transmission shaft output torque, actual load and vehicle actual road driving resistance curve during the vehicle driving process of the actual vehicle road load test; The process of obtaining the compensated test bench running resistance curve specifically includes the following steps: The actual road driving resistance curve of the whole vehicle obtained through the road coasting test is used as the benchmark driving resistance curve; an internal resistance coasting test is performed on the whole vehicle road load bench test device to obtain the bench internal resistance curve; the sample to be tested is installed on the whole vehicle road load bench test device and a coasting test is performed to obtain the bench driving resistance curve of the sample to be tested; based on the benchmark driving resistance curve, the bench driving resistance curve and the bench internal resistance curve, the bench driving resistance corresponding to each vehicle speed is compensated to obtain the compensated bench driving resistance curve.

2. The vehicle road load bench test method according to claim 1, wherein: The drive axle fixing fixture (2) includes a connecting seat (200), wherein a mounting channel for the drive axle body (6) to pass through is provided in the connecting seat (200); and a support arm (201) connected to the tire drum tester (1) is provided on the outer side of the connecting seat (200); The vertical loading system (3) comprises a hydraulic cylinder, the telescopic end of which extends into the installation channel and abuts against the drive axle body (6).

3. The vehicle road load bench test method according to claim 1, characterized in that: Conducting an internal resistance coasting test on a vehicle road load bench test device to obtain a bench internal resistance curve includes the following steps: Using the motor of the tire drum tester (1) to drive the dynamometer drum (4) to run to a set speed; Cutting off the power input of the dynamometer motor so that the dynamometer roller (4) can utilize its own inertia to overcome the internal resistance and slide; Record the time from the start of deceleration to zero speed and the total sliding distance; Obtaining an upper error limit and a lower error limit of a certain vehicle speed during deceleration from a set speed to zero, as well as a time corresponding to a coasting from the upper error limit of the certain vehicle speed to the lower error limit of the certain vehicle speed; and calculating a corresponding coasting distance based on the upper error limit, the lower error limit, and the time; Then, based on the kinetic energy theorem and the upper and lower error limits and the sliding distance, the internal resistance value of the test bench corresponding to a certain vehicle speed is calculated; Repeat the above steps to obtain the test bench internal resistance values ​​corresponding to multiple vehicle speeds to fit the test bench internal resistance curve.

4. The vehicle road load bench test method according to claim 3, characterized in that: The test sample is mounted on a vehicle road load bench test device and a coasting test is performed to obtain a bench driving resistance curve of the test sample, including the following steps: Using a control system to control the power system (7) and the transmission (8) of the sample to be tested, so that the transmission shaft (9) drives the wheel (5) to rotate to a set maximum speed; Cutting off the power input from the transmission (8) to the transmission shaft (9) to allow the wheel (5) to slide; Record the time taken by the wheel (5) from the start of deceleration to the speed reaching zero and the speed at each moment; Calculate the time difference and speed difference corresponding to the time it takes for the upper error limit of a certain speed to slide to the lower error limit of the same speed during the process of decelerating from the set speed to zero; then calculate the test bench driving resistance corresponding to the certain speed by combining Newton's second law; Repeat the above steps to obtain the bench running resistance corresponding to multiple vehicle speeds, and fit it into a bench running resistance curve.

5. The vehicle road load bench test method according to claim 4, characterized in that: Compensating the bench running resistance corresponding to each vehicle speed according to the reference running resistance curve, the bench running resistance curve, and the bench internal resistance curve to obtain a compensated bench running resistance curve includes the following steps: Obtaining the standard resistance corresponding to the reference running resistance curve, the test bench running resistance corresponding to the test bench running resistance curve, and the test bench internal resistance values ​​corresponding to the test bench internal resistance curve at the same vehicle speed; The intermediate value is obtained by subtracting the test bench running resistance value corresponding to the test bench running resistance curve and the test bench internal resistance value corresponding to the test bench internal resistance curve at the same vehicle speed; and then the intermediate value is compared with the standard resistance value corresponding to the reference running resistance curve. If the error between the intermediate value and the standard resistance value corresponding to the reference running resistance curve is less than the design error range, the running resistance corresponding to the vehicle speed in the running resistance curve meets the requirement; otherwise, the running resistance corresponding to the vehicle speed in the running resistance curve is compensated; Repeat the above steps to optimize the test bench running resistance corresponding to each vehicle speed in the test bench running resistance curve to obtain a compensation curve.

6. The vehicle road load bench test method according to claim 5, characterized in that: Compensating for the bench running resistance corresponding to the vehicle speed in the bench running resistance curve includes the following steps: The compensation value is obtained by subtracting the intermediate value from the standard resistance value corresponding to the reference driving resistance curve; The compensation value is added to the platform running resistance corresponding to the vehicle speed to obtain a new platform running resistance corresponding to the vehicle speed.

7. The vehicle road load bench test method according to claim 1, characterized in that: After the test sample and the vertical loading system (3) are controlled to operate by using the control data and the control system; the loading device of the tire drum tester (1) is controlled to adjust the running resistance in real time according to the compensated bench running resistance and the rotation speed of the dynamometer roller (4), and the following steps are also included: Determine whether the power system (7) and the temperature control system (10) have been preheated and have reached the same temperature and pressure as those in the actual vehicle road load test; If the value is reached, the step of adjusting the running resistance in real time according to the compensated bench running resistance curve and the speed control loading device of the tire drum tester (1) is performed; Otherwise, continue preheating.

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