Durability test method for off-road passenger vehicle off-road system

Abstract

The invention relates to a durability test method for a cross-country passenger vehicle cross-country system, and the method comprises the steps: collecting cross-country use condition information, and analyzing the proportion of each driving road condition through analyzing the daily driving road condition data of a cross-country user; construction of a load acquisition system and installation and debugging of test equipment; acquisition of load spectrums of domestic typical cross-country areas and professional cross-country test sites; construction of cross-country site test working conditions and result analysis. According to the invention, typical cross-country users and typical cross-country pavement research objects are added; in consideration of use conditions and stress characteristics of the cross-country passenger vehicle, the process of targeted cross-country test system construction, real vehicle road load spectrum acquisition and data optimization analysis is carried out, and the whole vehicle cross-country system durability test verification process of the cross-country passenger vehicle is converted into a special cross-country test site. Constructing a series of characteristic pavement test conditions for verification; the verification method is solidified, the professional blank is filled, and the verification requirement of the reliability and durability of the whole cross-country passenger car is met.

Description

Technical Field

[0001] The invention belongs to the technical field of automobiles, and in particular relates to a durability test method for an off-road system of an off-road passenger vehicle. Background Art

[0002] With the rapid development of the automobile industry, people's demand for automobiles is also increasing. Hard-core off-road vehicles have attracted many users with their unique power performance and passing performance. Hard-core off-road vehicles are mainly designed to meet the needs of users to pass through extremely harsh off-road roads. Common off-road roads for users include potholes, steep slopes, inclined roads, steps, deserts, gravel, and mud. The update and replacement of hard-core off-road vehicle products is very fast. In recent years, models with pure electric drive and hybrid drive have been produced. The characteristics of large motor drive torque are consistent with the requirements of off-road passenger cars, which has promoted the blowout of the hard-core off-road vehicle market. Faced with complex user off-road usage scenarios and the continuous replacement of new technologies, whether the off-road performance of hard-core off-road vehicles can be accurately and reliably verified has become a crucial part of the entire vehicle development process.

[0003] At present, the assessment of off-road vehicle performance mainly includes general passability, impact resistance, rescue and self-rescue capabilities, which involves examining the performance of vehicle components when subjected to extreme loads. For hardcore off-road vehicles, meeting the extreme passability and off-road performance is essential to establish a good reputation among off-road users and enhance product competitiveness. While verifying the performance, the reliable and durable performance of the off-road vehicle should also be guaranteed to reduce related failures during the off-road process of users, and reduce user complaints and product recall risks.

[0004] At the same time, existing off-road durability verification is mainly focused on:

[0005] 1. By conducting driving tests on reinforced bad roads consistent with ordinary passenger cars, the whole vehicle and parts are cyclically loaded until the end of the test, mainly to test the reliability and durability of the vehicle's load-bearing system. This method is more inclined to test the high-cycle fatigue of the whole vehicle and parts, and lacks the verification of the extreme load of parts in off-road scenarios commonly seen by typical off-road users, such as cross-axle roads and large-angle turning conditions;

[0006] 2. Adding off-road system assessment content to the adaptability test. Although there are some off-road road condition assessments such as desert, sand, rainforest, and mud, the types are relatively few and the user relevance is not high. At the same time, the test conditions will change with the different test time and seasons, and the key system problems related to off-road will be exposed later;

[0007] 3. The off-road durability test is replaced by the off-road passability test. However, the passability test mainly evaluates the off-road performance and cannot verify the ability to complete the specified functions under specified conditions, that is, the off-road reliability and durability.

[0008] Based on this, there is an urgent need to develop a test method for off-road reliability and durability verification of hard-core off-road vehicles, so that it can improve the assessment items of relevant hard-core off-road vehicles in order to fill the gap in reliability and durability verification of hard-core off-road systems. Summary of the invention

[0009] The purpose of the present invention is to provide a durability test method for the off-road system of an off-road passenger vehicle, so as to solve the problem of off-road reliability and durability verification of hard-core off-road vehicles, improve the assessment items of relevant hard-core off-road vehicles, and fill the gap in reliability and durability verification of hard-core off-road systems.

[0010] The objective of the present invention is achieved through the following technical solutions:

[0011] A durability test method for an off-road system of an off-road passenger vehicle comprises the following steps:

[0012] A. Collect off-road usage information, analyze the daily driving condition data of off-road users, and analyze the proportion of each driving condition;

[0013] B. Construction of load acquisition system and installation and commissioning of test equipment:

[0014] B1. Obtain the dangerous points of the components of the chassis and body systems through virtual simulation calculations, and determine the locations of characteristic measurement points;

[0015] B2. Paste strain gauges on the chassis system, including the steering rod and control arm, and the body system such as the crossbeam and longitudinal beam to measure the stress;

[0016] B3. Paste displacement sensors and acceleration sensors on the shock absorber, wheel axle head and body center of mass, and monitor the CAN protocol channel through the CAN bus acquisition system;

[0017] C. Collect load spectra of typical domestic off-road areas and professional off-road test sites:

[0018] C1. Determine the combination of D ditch, E desert, F mining area, G off-road mountain road and H forest off-road road for typical domestic users’ off-road areas;

[0019] C2. Determine the professional off-road test site to use the I test site;

[0020] C3. Collect load spectrum data in typical off-road areas and professional off-road venues in China. During the data collection process, use intense driving and simulated user driving to collect data on typical off-road conditions to the maximum extent;

[0021] D. Construction of off-road field test conditions and result analysis:

[0022] D1. Set C% road condition as off-road, calculate the collected typical off-road road load data, define the test condition as the user's typical off-road durability target, consistent with the vehicle strength of C%, and the test channel compliance is at least 80%;

[0023] D2. Construction and optimization analysis of off-road field test conditions: Comprehensively evaluate all vehicle systems and components, define off-road durability test conditions, compare damage between typical user off-road targets and off-road durability test conditions, and determine compliance based on the proportion of test channel strengths.

[0024] Furthermore, in step A, the road conditions that drivers drive on are relatively good, accounting for A% of the total, while the remaining B% of poor driving conditions include defective roads on national highways, defective roads in mountainous areas, off-road roads, Gobi and other roads, among which off-road roads account for C% of the total statistical road conditions.

[0025] Furthermore, in step A, the operating condition information includes but is not limited to road condition ratio, load condition, driving mode and driving speed.

[0026] Furthermore, in step B, all channels jointly record the load spectrum results under off-road conditions and record the load measurement information.

[0027] Furthermore, in step C1, the D ditch area covers cross-axle road conditions, gravel slopes, and riverbed and ditch road conditions that are commonly used to examine the off-road performance of vehicles; the E desert working condition includes desert crossing, sand dune climbing, and sand ridge crossing; the F mining area includes gravel roads and cross-axle road conditions; the G off-road mountain road and the F forest off-road road include rock slopes, pebble rivers, obstacle crossing, and cross-axle road conditions.

[0028] Furthermore, in step C2, the test site I includes 20 types of off-road characteristic roads, which can comprehensively assess the off-road vehicle's chassis, frame, power system, control system, sustained low-speed capability, mountain off-road driving mode assessment, differential lock, steering system, and steep slope descent capability.

[0029] Further, in step C3, the same road condition is driven at least 5 times.

[0030] Furthermore, in step D1, the test channel compliance is 92%.

[0031] Furthermore, in step D2, when judging the compliance by the ratio of the test channel strength, the rule is that the ratio is between 0.7 and 1.5, and the number of channels that comply is at least 80%.

[0032] Further, step D2 determines the number of cycles of the off-road venue I in the working conditions of small round bump composite impact road, pipeline road, V-shaped road, melon stone, cross axis, S curve, cobblestone road, sand, cement cross axis, ramp platform, rock road and cone pit.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The process of formulating the durability test method for the off-road system of an off-road passenger vehicle carried out in the present invention adds typical off-road users and typical off-road road surface research objects to the technical route process of formulating the final vehicle durability standard; considering the use conditions and stress characteristics of off-road passenger vehicles, a targeted off-road test system is constructed, a real vehicle road load spectrum is collected, and a data optimization and analysis process is carried out; the off-road system durability test verification process of the off-road passenger vehicle is transformed into a dedicated off-road test site, and a series of characteristic road surface test conditions are constructed for verification; the verification method is solidified to fill the professional gap and meet the verification needs of the reliability and durability of the off-road passenger vehicle as a whole. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0036] Figure 1 Schematic diagram of the proportion of driving road surface;

[0037] Figure 2 Schematic diagram comparing the intensity of typical off-road user conditions and off-road test field conditions;

[0038] Figure 3 Schematic diagram comparing absolute damage between typical off-road user conditions and off-road test field conditions;

[0039] Figure 4 A flow chart of the steps of a durability test method for an off-road system of an off-road passenger vehicle according to the present invention. DETAILED DESCRIPTION

[0040] The present invention will be further described below in conjunction with embodiments:

[0041] The present invention takes the existing durability test verification system as the main body, and keeps the vehicle assessment strength target unchanged. Conduct off-road user use surveys to determine the proportion of driving on off-road roads and replace it with typical off-road conditions; build a test system for the entire vehicle including suspension, frame, body, control system (CAN), etc., with special attention paid to the large suspension travel and large frame torsion conditions in off-road conditions; collect data in areas where typical hard-core off-road vehicles are concentrated in China to obtain the off-road condition load of actual users; conduct an off-road durability test method that combines medium-intensity fixed cycle test conditions with the number of passes of high-intensity off-road conditions to assess the reliable durability of hard-core off-road vehicles, which is more in line with the use of hard-core off-road users in terms of verification strength and test conditions.

[0042] The durability test method of the off-road system of an off-road passenger vehicle of the present invention comprises the following steps:

[0043] 1. Collect relevant off-road use condition information through a typical off-road user questionnaire survey, including but not limited to road condition ratio, load condition, driving mode and driving speed. The specific user survey form content example is shown in Table 1.

[0044] Table 1 Off-road user survey form (example)

[0045]

[0046] By analyzing the daily driving road condition data of off-road users, it was found that most drivers have good driving conditions, accounting for A% of the total, while the remaining B% of poor driving conditions mainly include defective road conditions on national highways, defective road conditions in mountainous areas, off-road roads, Gobi and other roads, among which off-road roads account for C% of the total statistical road conditions.

[0047] 2. Construction of load acquisition system and installation and commissioning of test equipment.

[0048] By calculating the total damage of off-road passenger vehicle parts under different test schemes, the corresponding assessment strength is compared. If the cumulative damage of the two schemes is similar, the assessment strength is considered to be the same. The load measurement method of vehicle parts is recorded by strain gauges, acceleration and displacement sensors and CAN bus. According to the purpose of the off-road system durability load spectrum collection test, a full vehicle test system including suspension, frame, body, control system (CAN) was constructed, with special attention paid to the large suspension travel and large frame torsion in off-road conditions.

[0049] First, the dangerous points of the components of the chassis and body systems are obtained through virtual simulation calculations, and the locations of characteristic measurement points are determined. After that, strain gauges are attached to the chassis system such as the steering rod and control arm, and the body system such as the crossbeam and longitudinal beam to measure the stress. Displacement sensors and acceleration sensors are attached to the shock absorber, wheel axle head and body center of mass, and the CAN protocol channel is monitored through the CAN bus acquisition system. All the above channels jointly record the load spectrum results under off-road conditions, and the measurement information is shown in Table 2.

[0050] Table 2 Load measurement information

[0051] Measuring signal Channel Name Purpose of the test Sensor Type Spring displacement D_spring Displacement Wire Displacement Sensor Shock absorber sliding rod axial force Fz_jzqhz Displacement Wire Displacement Sensor Body measuring point 1 F_strain1 stress Strain gauge …… …… …… …… Front stabilizer bar torsion F_TorsionBar stress Strain gauge Rear stabilizer bar torsion R_TorsionBar stress Strain gauge Front control arm system stress F_kzb stress Strain gauge Rear suspension rod stress F_barsystem stress Strain gauge Frame torsion / bending forces F_twist / bend stress Strain gauge Three-axis acceleration at the shaft head A_Axle Acceleration Accelerometer Three-dimensional acceleration of the vehicle body suspension A_Cab Acceleration Accelerometer Three-axis acceleration of vehicle center of mass A_COG Acceleration Accelerometer CAN bus test channel -- -- -- …… …… …… ……

[0052] 3. Collect load spectra from typical domestic off-road areas and professional off-road test sites.

[0053] Through the investigation and analysis of typical off-road areas and off-road conditions in China, it is determined that the typical user off-road area in this test method adopts a combination of D ditch, E desert, F mining area, G off-road mountain road and H forest off-road road. Among them, the D ditch area covers the cross-axle road, gravel slope, river beach and river ditch and other road conditions commonly used to examine the off-road performance of vehicles; the E desert working condition includes desert crossing, sand dune climbing and sand ridge crossing; the F mining area includes gravel roads, cross-axle roads and other road conditions; the G off-road mountain road and F forest off-road road include rock slopes, pebble rivers, obstacles, cross-axle and other road conditions.

[0054] After analyzing and comparing multiple professional off-road test sites in China, it was determined that the off-road test site in this test method is the I test site. The I test site contains about 20 types of off-road characteristic roads, covering typical domestic off-road roads. It can comprehensively assess the off-road vehicle's load-bearing system (chassis, frame), power system, control system, continuous low-speed capability, mountain off-road driving mode assessment, differential lock, steering system, steep slope descent and other capabilities.

[0055] Load spectrum data were collected on-site in the above-mentioned typical off-road areas and professional off-road venues. The same road condition was driven at least 5 times to ensure data validity. During the data collection process, both intense driving and user-simulated driving were used to collect data on typical off-road conditions to the maximum extent possible.

[0056] 4. Construction of off-road field test conditions and analysis of results.

[0057] 41. Off-road durability target setting for typical off-road users

[0058] According to the results of satisfying the user survey, the C% road condition is off-road, and the typical off-road load data collected is calculated. The test conditions in Table 3 are defined as the typical off-road durability target of the user. Consistent with the vehicle strength of C%, the test channel compliance is 92% (required to be at least 80%).

[0059] Table 3 Definition of typical user off-road goals

[0060] Typical user off-road area Number of trips D groove J1 Desert J2 F Mining Area J3 G off-road mountain road J4 H Forest Off-road J5

[0061] 42. Construction and optimization analysis of off-road field test conditions

[0062] Comprehensively assess all vehicle systems and components, and define off-road durability test conditions as shown in the following table. Compare the damage of typical user off-road targets with off-road durability test conditions, and 85% of the test channels have the same strength (the rule is that the ratio is between 0.7 and 1.5, and the number of channels that meet the requirements is at least 80%), with a high degree of compliance.

[0063] Table 4 Off-road durability verification field condition cycle number

[0064] I Cross-country venue Number of cycles Small round protrusion K1 Composite impact road K2 Pipeline Road K3 V-shaped road K4 Guami Stone K5 Cross Axis K6 S-bend K7 Pebble Road K8 Sandy K9 Cement cross axis K10 Ramp K11 Rocky Road K12 Cone pit K13

[0065] The innovation of the present invention lies in the establishment of an off-road system durability test method, including a typical off-road user questionnaire survey, a load spectrum test system construction technology for off-road passenger vehicles, typical user off-road area load spectrum collection, professional off-road test site load spectrum collection, and corresponding association and optimization analysis of off-road passenger vehicle typical user load spectrum and professional off-road site load spectrum. Among them, the test conditions of the present invention are based on the results of off-road users and market research and the test experience in the product development process. In the typical user off-road road surface and professional off-road test site, the user driving mode is simulated to collect load spectrum data, and the off-road system durability test method of off-road passenger vehicles is designed by applying amplitude statistics, load loading phase analysis, fatigue strength analysis and data fitting. The test conditions of the present invention cover the typical user off-road road conditions and technical parameters, and carry out user association of driving mode and driving mode, and fit the domestic off-road vehicle target setting and user use process to the maximum extent. The load spectrum test construction technology of the present invention and the definition of the typical user off-road condition target are the key test requirements of the test process.

[0066] The method used in the present invention is based on the existing durability test verification system, keeping the vehicle assessment strength target unchanged. Conduct off-road user use surveys to determine the proportion of driving on off-road roads and replace it with typical off-road conditions; build a test system for the entire vehicle including suspension, frame, body, control system (CAN), etc., with special attention paid to the large suspension travel and large frame torsion conditions in off-road conditions; collect data in areas where typical hard-core off-road vehicles are concentrated in China to obtain the off-road load of actual users; conduct an off-road durability test method that combines medium-intensity fixed cycle test conditions with the number of passes of high-intensity off-road conditions to assess the reliable durability of hard-core off-road vehicles, which is more in line with the use of hard-core off-road users in terms of verification strength and test conditions.

[0067] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A durability test method for an off-road system of an off-road passenger vehicle, characterized in that: The following steps are involved: A. Collect off-road usage information, analyze the daily driving condition data of off-road users, and analyze the proportion of each driving condition; B. Construction of load acquisition system and installation and commissioning of test equipment: B1. Obtain the dangerous points of the components of the chassis and body systems through virtual simulation calculations, and determine the locations of characteristic measurement points; B2. Paste strain gauges on the chassis system, including the steering rod and control arm, and the body system such as the crossbeam and longitudinal beam to measure the stress; B3. Paste displacement sensors and acceleration sensors on the shock absorber, wheel axle head and body center of mass, and monitor the CAN protocol channel through the CAN bus acquisition system; C. Collect load spectra of typical domestic off-road areas and professional off-road test sites: C1. Determine the combination of D ditch, E desert, F mining area, G off-road mountain road and H forest off-road road for typical domestic users’ off-road areas; C2. Determine the professional off-road test site to use the I test site; C3. Collect load spectrum data in typical off-road areas and professional off-road venues in China. During the data collection process, use intense driving and simulated user driving to collect data on typical off-road conditions to the maximum extent; D. Construction of off-road field test conditions and result analysis: D1. Set C% road condition as off-road, calculate the collected typical off-road road load data, define the test condition as the user's typical off-road durability target, consistent with the vehicle strength of C%, and the test channel compliance is at least 80%; D2. Construction and optimization analysis of off-road field test conditions: Comprehensively evaluate all vehicle systems and components, define off-road durability test conditions, compare damage between typical user off-road targets and off-road durability test conditions, and determine compliance based on the proportion of test channel strengths.

2. The durability test method of an off-road system of an off-road passenger vehicle according to claim 1, characterized in that: In step A, the drivers drive on good road conditions, accounting for A% of the total, while the remaining B% of poor driving conditions include defective roads on national highways, defective roads in mountainous areas, off-road roads, Gobi and other roads, among which off-road roads account for C% of the total statistical road conditions.

3. The durability test method of an off-road system of an off-road passenger vehicle according to claim 1, characterized in that: In step A, the operating condition information includes but is not limited to road condition ratio, load condition, driving mode and driving speed.

4. The durability test method of an off-road system of an off-road passenger vehicle according to claim 1, characterized in that: Step B: All channels jointly record the load spectrum results under off-road conditions and record the load measurement information.

5. The durability test method of an off-road system of an off-road passenger vehicle according to claim 1, characterized in that: Step C1, the D ditch area covers the cross-axle road surface, gravel slope road, river beach and ditch road conditions commonly used to examine the off-road performance of the vehicle; the E desert working condition includes desert crossing, sand dune climbing and sand ridge crossing; the F mining area includes gravel roads and cross-axle road conditions; the G off-road mountain road and the F forest off-road road include rock slopes, pebble rivers, obstacle crossing, and cross-axle road conditions.

6. The durability test method of an off-road system of an off-road passenger vehicle according to claim 1, characterized in that: Step C2, the I test site includes 20 types of off-road characteristic roads, which can comprehensively test the off-road vehicle's chassis, frame, power system, control system, continuous low-speed capability, mountain off-road driving mode assessment, differential lock, steering system and steep slope descent capability.

7. The durability test method of an off-road system of an off-road passenger vehicle according to claim 1, characterized in that: Step C3: driving on the same road condition at least 5 times.

8. The durability test method of an off-road system of an off-road passenger vehicle according to claim 1, characterized in that: Step D1, the test channel compliance is 92%.

9. The durability test method of an off-road system of an off-road passenger vehicle according to claim 1, characterized in that: In step D2, when judging the compliance by the ratio of the test channel strength, the rule is that the ratio is between 0.7 and 1.5, and the number of channels that comply is at least 80%.

10. The durability test method of an off-road system of an off-road passenger vehicle according to claim 1, characterized in that: Step D2, determining the number of cycles of the off-road venue I in the working conditions of small round bump composite impact road, pipeline road, V-shaped road, melon stone, cross axis, S curve, cobblestone road, sand, cement cross axis, ramp platform, rock road and cone pit.

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