JB/T 7235-1994 Test methods for four-wheeled agricultural transport vehicles
Some standard content:
Mechanical Industry Standard of the People's Republic of China
Test Methods for Four-wheeled Agricultural Transport Vehicles
1 Subject Content and Scope of Application
This standard specifies the test methods for determining the various performances of four-wheeled agricultural transport vehicles. This standard applies to the whole vehicle test of four-wheeled agricultural transport vehicles (hereinafter referred to as agricultural transport vehicles). 2 Reference standards
GB3846
GB6236
GB7031
GB7258
GB7454
GB/T3871.10
3 General requirements
3.1 General test conditions
Terms and definitions of motor vehicles and trailers Vehicle dimensions Method of measuring free acceleration smoke density of diesel vehicles
Agricultural tractor Driver's seat marking points
Vehicle vibration input Method of expressing road surface flatness Technical conditions for motor vehicle operation safety
Technical regulations for the use and beam adjustment of motor vehicle headlamps JB/T7235-94
Test methods for agricultural wheeled and crawler tractors Part 10 Cold starting test
Unless otherwise specified, each test must meet the following requirements. 3.1.1 The following items must be consistent with the technical documents accompanying the vehicle: the structure and performance of each assembly, accessory and auxiliary device of the test vehicle; the technical status of the test vehicle, the adjustment and operation methods of each part; the fuel, lubricating oil, coolant and other working fluids used during the test. 3.1.2 During the entire test period, except for routine maintenance and adjustment in accordance with the provisions of the instruction manual, no other adjustments and replacements are allowed. If necessary, it must be approved by the test organization and carried out under its supervision, and then the relevant items will be tested again, and the details will be recorded in the report. 3.1.3 The tire pressure during the test should comply with the provisions of the technical documents accompanying the vehicle. Except for the reliability test, the tires must not have mud and oil. 3.1.4 Except for special provisions, the load during the test should be kept at the rated full load, and the load should be an item whose mass and shape will not change due to changes in climate and use conditions. It should be evenly placed in the car box, and its movement should be restricted, and its height should not exceed the car box side panel. The number of passengers (including the driver) on the vehicle shall comply with the provisions of the accompanying technical documents, but heavy objects may be placed in the corresponding positions to replace passengers, and each person shall be calculated as 65kg (55kg on the seat and 10kg on the front floor). 3.1.5 Except for the reliability test, which is not restricted by climatic conditions, all other tests shall be conducted in rainless weather with a temperature of 20±15℃ and a wind speed of no more than 3m/s at a height of 1.2m above the ground (except for special provisions). At the beginning and end of each test, the temperature, wind speed and air pressure shall be measured and recorded, and their ranges shall be reported. 3.1.6 Unless otherwise specified, the test shall be conducted on a clean, dry, flat asphalt or concrete road surface, with a longitudinal slope of less than 0.1% and a transverse slope of no more than 0.3%. The length of the straight section shall not be less than 1500m and the width shall not be less than 8m. 3.1.7 Before conducting various performance tests, the test vehicle shall be preheated so that all parts reach the normal operating temperature. 3.1.8 Except for the reliability driving test, which can open the windows, the rest of the tests should be conducted with the doors and windows closed. Approved by the Ministry of Machinery Industry on July 18, 1994
Implemented on July 1, 1995
JB/T7235-94
3.1.9 The accuracy of the instruments and equipment used in the test should meet the measurement accuracy requirements and be within the validity period of their calibration. 3.1.10 All abnormal phenomena that occur during the test should be recorded in detail and written into the report. 3.2 Measurement accuracy
3.2.1 Unless otherwise specified, the measurement accuracy of various parameters shall meet the following requirements: distance ±0.5%, operating force ±5%, mass ±1.0%, time ±0.2s, torque ±1.0%, speed ±1.0%, vehicle speed ±3.0%, oil pressure or air pressure ±2%, ambient temperature ±0.5℃, water temperature and oil temperature ±2℃, angle ±1°, atmospheric pressure ±0.2kPa, tire pressure ±10kPa, noise level ±0.5dB(A), others ±2%.
3.2.2 When making precise measurements of part dimensions and adjusting fitting clearances, the measurement accuracy shall be consistent with the accuracy requirements of the dimensions being measured. 3.2.3 When recording the number of kilometers driven, just record to the nearest integer. 4 Acceptance and running-in of test vehicle
4.1 The test vehicle shall be fully inspected and accepted by the test responsible unit according to the acceptance technical conditions of the transport vehicle or other relevant documents. The inspection items are listed in Table 1 and the inspection results are recorded in the table. 4.2 Before the test, the test vehicle shall be run-in and maintained in accordance with the provisions of the accompanying technical documents. The running-in situation shall be recorded in Table 1. 4.3 After running-in and maintenance, and before the performance test, the odometer of the test vehicle shall be calibrated and the results shall be recorded in Table 1. During the inspection, the test vehicle shall accurately drive along a route of known distance (the route length shall not be less than 25km), record the mileage displayed on the odometer when passing this section, and calculate the correction coefficient of the odometer of the test vehicle according to formula (1), C.
Where: C is the odometer correction coefficient;
S is the actual mileage, km;
S, — odometer indication, km.
5 Vehicle parameter measurement
5.1 Measurement conditions
5.1.1 Except for the commonly used on-board tools and the original spare tire, no overloaded cargo, sundries, dirt, etc. are allowed on the test vehicle. 5.1.2 Fuel, lubricating oil, coolant and other working fluids should be filled to the highest liquid level specified in the technical documents. ·(1)
5.1.3 All adjustable or changeable parts that affect the external dimensions of the test vehicle, such as the flip cab, dump box, etc., should be in a stable state with the minimum external dimensions. 5.1.4 When measuring dimensional parameters, the test vehicle should be parked on a hard and level ground. The ground slope within the test range should not exceed 0.3% and the ground flatness should be within 3mm.
5.1.5 The test vehicle is in a straight-line driving position. For adjustable passenger seats, they should be placed in the middle position. 5.1.6 During the measurement, the engine is turned off, the gear lever is in the neutral position, the brake is released, and no wooden blocks are allowed. 5.2 Instruments and equipment
Steel tape measure or other linear dimension measuring device, scale or other weighing device, angle meter, etc. 5.3 Determination method
5.3.1 Dimension parameters
Measure the overall dimensions of the test vehicle and the dimensions of the cargo box, etc. The measurement items are listed in Table 2 and shown in Figure 1. The definition of each parameter shall be in accordance with the provisions of GB3730.3.
5.3.2 Mass parameters
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Figure 1 Schematic diagram of vehicle size parameters of transport vehicles
It includes the total mass of the test vehicle and the mass distribution on the front and rear axles, and is measured in the empty vehicle condition (with driver and no cargo, the same below) and rated full load condition (with all passengers and specified load, the same below). 5.3.3 Center of mass coordinates
The center of mass coordinates of agricultural transport vehicles are represented by a, e, and h (see Figure 1). a is the longitudinal coordinate of the center of mass, that is, the horizontal distance from the center of mass to the rear axle; e is the center of mass. The horizontal coordinate of the center of mass, that is, the distance from the center of mass to the longitudinal center plane of the agricultural transport vehicle. When the center of mass is on the right side of the plane, an asterisk is placed before the value of e. Otherwise, no asterisk is placed. a and e are calculated from the measurement results in 5.3.2 according to equations (2) and (3). h is the height coordinate of the center of mass, that is, the distance from the center of mass to the rigid support plane of the wheel. It is measured and calculated according to the two common measurement methods and calculation formulas introduced in Appendix A (reference). The swing method is recommended, and the moment balance method can also be used. The measurements should be carried out under empty vehicle and rated full load conditions respectively.
5.4 Determination results Results and Reports
5.4.1 Calculation formula for center of mass coordinates
Longitudinal coordinate of center of mass
Where: a-
Longitudinal coordinate of the center of mass of the test vehicle, mm;
Ground support reaction of the front wheels when the test vehicle is parked horizontally, N; Mass of the test vehicle, kg;
Wheelbase of the test vehicle, mm;
Gravity acceleration, m/s.
Transverse coordinate of center of mass
Transverse coordinate of the center of mass of the test vehicle, mm;
Where: e-
B-Average of the wheelbase of the front and rear wheels of the test vehicle , mm; 0.5)
Z,—The ground support reaction force of the left wheel when the test vehicle is parked horizontally, N. (2)
+（3）bZxz.net
c. Height coordinate of the center of mass
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The calculation formula of the height coordinate of the center of mass h varies with the test method, see Appendix A. 5.4.2 Record the test conditions and various measurement results in Table 2. 6 Engine main performance test
6.1 Test conditions
6.1.1 The ambient temperature of the test site should be 23±7℃, and the atmospheric pressure should not be lower than 96.6kPa. If the atmospheric pressure requirement cannot be met due to altitude restrictions, the fuel injection pump may be adjusted to improve the engine's working condition, and the adjustment shall be recorded in the report. 6.1.2 During the test, the engine shall be equipped with accessories necessary for normal operation, such as fans, air filters, water tanks and exhaust mufflers, etc. The exhaust can be connected to the laboratory's air discharge device (but it cannot affect the engine's performance). Other accessories (such as generators, hydraulic pumps, air pumps, etc.) shall be in a no-load state or disconnected from the drive. 6.1.3 During the test, an external fuel tank shall be used for fuel supply, and the temperature of the diesel shall be controlled at 40±5℃. 6.1.4 Unless otherwise specified, all tests shall be carried out continuously with the throttle fully open. When measuring various parameters, they shall be carried out after they have stabilized for at least 1 minute.
6.2 Instruments and Equipment
Dynamometer, fuel consumption meter, tachometer, timer, thermometer and barometer, etc. 6.3 Test Method
The engine is directly connected to the dynamometer and the following test is carried out. 6.3.1 Rated power test
The engine is continuously and steadily loaded to reach the rated speed and maximum power condition, and it is operated under this condition for 1 hour. The following parameters are measured once at the beginning, middle and end of the test: torque, speed, fuel consumption, fuel temperature, lubricating oil temperature, coolant temperature, intake temperature, ambient temperature, atmospheric pressure and relative humidity. If the difference between the power measurement results exceeds 2%, the test should be repeated. If the repeated results are still out of tolerance, the deviation should be recorded in the report. The speed, torque and fuel consumption should be measured at the same time, and the time for measuring fuel consumption should not be less than 30s. The measurement positions of various temperatures are as follows:
Ambient temperature: measured on the same side of the engine air filter, 1.5m away from the outside of the air filter and 1.2m above the ground. Intake temperature: measured 5cm away from the outer wall of the engine air filter inlet and away from the engine body. Fuel temperature: measured as close to the fuel inlet of the injection pump as possible. Lubricating oil temperature: measured in the main oil channel or at 1/2 of the oil depth in the oil pan. Coolant temperature: measured at the engine coolant outlet. For air-cooled engines, measure the air flow temperature at the point specified by the manufacturer. 6.3.2 Determination of minimum no-load stable speed
Disconnect the engine from the dynamometer, gradually reduce the throttle to the lowest speed, and measure that the engine should be able to run stably at this speed for at least 5 minutes. Measure three times and take the average value.
6.4 Test results and report
6.4.1 The test results of each test shall be calculated according to formulas (4) to (6). a. Engine power
Where: P.--engine power, kW;
T., engine torque, N·m;
n. Engine speed, r/min.
b. Hourly fuel consumption
G, =3. 64G
·（4）
（5）
Where: G,—hourly fuel consumption, kg/h; JB/T7235-94
AG—fuel consumption during the measurement time, g; t—measurement time, s.
c. Fuel consumption rate
Where: g—fuel consumption rate, g/(kW·h). 6.4.2 Record the results of each measurement and calculation in Table 3. (6)
6.4.3 For each test result, only the measured value shall be published. For parameters that are measured multiple times, only the arithmetic mean value shall be published (temperature parameters shall publish their range).
7 Dynamic performance test
7.1 Test conditions
The test road should be a road with good adhesion performance. The climbing test is carried out on a ramp with a longitudinal slope. At the appropriate section of the test road, a section of a specified length is marked as the test area. There should be a sufficiently long auxiliary working section at both ends of the test area. 7.2 Instruments and equipment
Five-wheel instrument, timer, steel tape measure, slope meter, thermometer and anemometer, etc. 7.3 Test method
7.3.1 Minimum stable vehicle speed determination
During the test, the test vehicle is put in the lowest gear, driven at the smallest possible throttle, and driven into the test area at the minimum speed for stable driving. The test area is 100m long, and the time to pass the test area is recorded. After passing the test area, immediately step down the accelerator pedal to accelerate. During this period, the engine should not be turned off and the transmission system should not vibrate. If the above situation occurs, the vehicle speed should be appropriately increased and the test should be repeated. The test should be repeated until the lowest stable speed at which the test vehicle can accelerate smoothly is found. The test should be carried out at least twice in both directions. The time to pass through the test area should be recorded and the arithmetic average should be taken. Then, the lowest stable speed of the highest gear should be tested in the same way. 7.3.2 Determination of the highest speed
Start the test vehicle from a place far enough away from the test area, shift gears and accelerate to the highest gear, and step on the accelerator to the bottom. The test vehicle has the highest speed at least 20m before arriving at the test area, and maintains the stable speed to pass through the test area. The length of the test area is 200m. The test should be carried out once in both directions. The time to pass through the test area should be recorded and the average should be taken. 7.3.3 Acceleration performance test
On the straight section test road, a sufficiently long test test area is marked in the middle, and a 100m speed test area is marked at both ends for measuring the initial speed. The test vehicle is tested on this road for the following two acceleration performance tests. a. Acceleration performance of the highest gear
The test vehicle is put into the highest gear and driven at a speed 10% higher than the minimum stable speed of the gear. It passes through the speed measurement area at a constant speed and the passing time is recorded. When it reaches the starting point of the acceleration measurement area, the accelerator is immediately pushed to the bottom and the test vehicle is driven through the measurement area quickly until it is accelerated to more than 80% of its maximum speed. The whole acceleration process is continuously recorded with a five-wheel instrument, and the speed, time and distance are recorded. The test is carried out once for each round trip, and the average value of the two measurements at the same speed is taken as the measurement result at the speed. b. Acceleration performance of continuous gear shifting at start
Before the test, the driver should first fully practice the process of gear shifting at start on the test road to determine the best gear shifting condition (the acceleration time and acceleration distance should be the shortest at this time). During the test, the test vehicle stops at the starting point of the test area, immediately starts in the starting gear from the start command and accelerates as quickly as possible. At the best gear shifting moment, the vehicle is quickly and silently shifted to a higher gear, and then the vehicle is continuously shifted to the highest gear as quickly as possible and accelerated to more than 80% of the maximum vehicle speed. The whole acceleration process is continuously recorded with a five-wheel instrument, and the speed, time and distance are measured. The test is carried out once for each round trip, and the average value of the two measured values at the same speed is taken as the result. 7.3.4 Determination of maximum climbing ability
JB/T 723594
Select a section of the road with a slope close to the maximum climbing slope (design value) of the test vehicle, uniform slope, sufficient slope length, and a flat road or gentle straight slope at the bottom of the slope as the test road. Set a 25m long speed measurement area on the slope, and the starting point of the measurement area is 20m away from the bottom of the slope. The slope measurement should be measured at three representative locations at the beginning, end and middle section of the slope, and the average value should be taken. During the test, the test vehicle starts with the lowest gear from the flat road section about 20m away from the bottom of the slope, and immediately drives up the slope with the accelerator to the bottom, and the time to pass the measurement area is measured. If the vehicle cannot climb the slope and is forced to stop, the load should be reduced and the test should be repeated. If the slope of the test road is not suitable (large or small), the load or gear can be changed to change the driving method and the test can be repeated. Until the vehicle can or cannot just pass the test area after reducing or increasing by about 50kg (25kg for the test vehicle with a total mass less than 1500kg). After the test, the test result under this critical state is converted into the maximum slope that can be climbed when climbing the slope with the lowest gear at the rated load according to formula (10). When increasing the load, the load shall not exceed the limit of the component strength. If restricted by terrain conditions, the traction simulation method can also be used for measurement on a straight road with good adhesion performance. During the test, the test vehicle is rated fully loaded, engaged in a suitable gear, and tows a load vehicle (with a dynamometer connected in series), gradually increasing the load, measuring the maximum traction that can be exerted when the engine of the test vehicle is about to shut down, and then calculating its maximum climbing grade according to formula (11). 7.4 Test results and report
7.4.1 The test results are calculated using formulas (7) to (10) respectively. a.
Average driving speed
Where: 0
Average driving speed, m/s;
Length of measuring area, m;
Time to pass through the measuring area, S.
Average acceleration
Where: aj——average acceleration, m/s\,—stable speed before acceleration, m/s:
—speed when accelerating to 80% of the maximum speed, m/s; t-acceleration time from to\, s.
c. Conversion of maximum climbing grade
Jmu=100tgamax
Climbing method:
=arcsin
Simulation method:
arcsin
Where: J..
Conversion of maximum climbing grade, %;
Conversion of maximum slope angle of ramp, (\);
Slope angle of a test ramp, (\);
m.Rated total mass of the vehicle under test, kg;
m, — actual total mass of the vehicle under test during the test, kg; ii — total transmission ratio of the lowest gear of the vehicle under test; — total transmission ratio of the gear actually used during the test; FTmar
— maximum traction, N.
*(10)
·（11)
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7.4.2 Record the results of various measurements and calculations in Table 4. For the test in Article 7.3.3, two acceleration process performance curves, namely t- and S-curves, should be drawn respectively, where \ is the vehicle speed reached, t is the acceleration time, and S is the acceleration distance, and at least 8 measuring points should be distributed between them. In addition, the average acceleration when the direct gear accelerates to 80% of its maximum vehicle speed should also be calculated. For the test results of Article 7.3.4, when the maximum slope angle αm of the converted ramp is greater than the departure angle αm or approach angle αm of the test vehicle, this angle or this angle shall be used as the maximum slope angle and stated in the report. 8 Fuel economy test
8.1 Test conditions
According to the requirements of Article 3.1.
8.2 Instruments and equipment
Fuel consumption meter, five-wheel meter, steel tape measure, timer, anemometer and thermometer, etc. 8.3 Test method
8.3.1 Constant speed driving fuel economy test
At the appropriate section of the test road, mark out a 500mm long section as the test area. There should be a long enough preparation area at both ends of the test area so that the test vehicle can obtain a stable speed at least 20m before entering the test area. Engage the highest gear and conduct the following two tests. a. Determination of average fuel consumption at constant speed under six working conditions
During the test, start the vehicle and shift to the highest gear before leaving the test area. Set the throttle to a certain position, keep the test vehicle at a certain stable speed, first pass the speed test area (to confirm whether the predetermined requirements are met) and then enter the test area, and measure the time and fuel consumption of passing the test area. The test vehicle speed v should be taken as 100%, 90%, 80%, 70%, 60% and 50% of the maximum speed V. (allowable deviation ±2%), and go back and forth once at each speed, and take the average value. b. Economic fuel consumption determination
The test is carried out immediately after test a, and then a number of additional points (including the lowest stable speed condition) are measured to draw a curve of the relationship between fuel consumption and speed until the lowest fuel consumption gTmi and the corresponding speed are found: 8.3.2 Determination of fuel consumption under variable conditions
In the middle of the straight section of the test road, a 1000m long section is taken as the measurement area, which is divided and marked into seven sections with lengths of 50, 150, 150, 150, 300, 100, and 100m, respectively. They are A, B, C, D, E, F, and G, as shown in Figure 2. (km/h)
Drinking high gear
Top gear
Top gear
Sliding, braking
Sub-high gear
9001000
Figure 2 Schematic diagram of the layout of the fuel consumption measurement site and operating requirements for variable operating conditions When encountering the
test, the test vehicle is in the sub-high gear, which is one gear lower than the top gear, and passes through area A at a stable speed (v=0.25vm or 1.1Vmin, whichever is larger, U and Ui are the highest speed and the lowest speed of the test vehicle in the top gear respectively); from arriving Starting from the starting point b of the B zone, smoothly shift to the highest gear and accelerate to the point c to reach the speed of us (vz=0.5um) and keep it unchanged to complete the C zone; starting from the starting point d of the D zone, uniformly accelerate to the point e to reach the speed of (\二m) and keep it unchanged to complete the E zone; when the test vehicle reaches the starting point f115
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of the F zone, immediately shift the gear and glide, and use the brake appropriately as needed, so that the test vehicle gradually decelerates to the speed of exactly when it arrives at the starting point g of the G zone, and immediately shift to the next highest gear and keep the speed uniform to pass the G zone. Measure the total fuel consumption and total time when the test vehicle passes through the above seven sections continuously, and the driving speed tolerance is ±0.5km/h. After completing the above test, immediately repeat this test from the opposite direction (but the site shown in Figure 2 should also be rearranged in the opposite direction), and test twice in each round trip (the difference in the two fuel consumption measurements should not be greater than 5% of the average value), and take the arithmetic average. 8.3.3 Determination of fuel consumption under limited conditions
The test vehicle is driven on a level third-class highway in the test area in a normal traffic condition in a conventional manner. Its average speed should not be less than 60% of the maximum speed. It is driven back and forth once on a 50km long section of road and the total fuel consumption is measured and recorded. If it is necessary to stop during driving, the engine should be turned off and the engine is not allowed to run rapidly for a long time. The stopping time is recorded. 8.4 Test results and report
8.4.1 The test results of each item are calculated using equations (12) to (15). Fuel consumption
Where: GTs
Fuel consumption per 100 kilometers, L/100km;
-Fuel consumption when passing through the test area, mL; s—length of the test area, m
×100:
-Constant speed fuel consumption rate under each speed condition, L/(t·100km); gt
gm-Average constant speed fuel consumption rate under six conditions, L/(t·100km); m.
Gross mass of the test vehicle, kg.
b. Economic speed range ratio
Where: w
Economic speed range ratio, %;
The speed corresponding to the point with the lowest fuel consumption gTuin in the constant speed fuel economy test, km/h; Auj-The change in speed between the two points with a specific fuel consumption of 1.1gtmi, km/h. (12)
.*（13）
（14)
+（15）
8.4.2 Record the results of various measurements and calculations in Table 5. For the test in Article 8.3.1.b, a constant speed fuel economy curve including Grs- and gT-curves shall be drawn. The vehicle speed at the lowest specific fuel consumption gTmia and the speed change between two points with a specific fuel consumption of 1.1gTml (when the intercept point is outside the curve, the curve endpoints shall be used) shall be obtained from the curve, and the economic speed range ratio @ shall be calculated and recorded in the table. For the test results in Articles 8.3.2 and 8.3.3, only the arithmetic mean value shall be announced. 9 Coasting test
9.1 Test conditions
As required in Article 3.1, but the wind speed shall not exceed 1m/s. 9.2 Equipment only
Anemometer, five-wheel instrument or steel tape measure, timer, etc. 9.3 Test method
On the straight section of the test road, mark out a 100m long speed measurement area and a sufficiently long sliding area. 116
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During the test, the test vehicle is in the highest gear and drives into the speed measurement area at a constant speed as follows: 30km/h when the highest speed design value is higher than 30km/h, and 20km/h otherwise. When the vehicle just passes the speed measurement area and enters the sliding area, the clutch is immediately disengaged and the vehicle is in neutral gear and slides until it stops. The time to pass the speed measurement area and the sliding distance from the start of sliding to the stop are recorded. The test is carried out twice each way and the average value is taken. 9.4 Test results and report
Use formula (7) to calculate the initial speed before sliding. When the initial speed before sliding is within ±5% of the initial sliding speed value specified in Table 5, use formula (16) to calculate the sliding distance at the specified initial speed. Otherwise, the test is invalid and should be repeated. Record the measurement and calculation results in Table 6. S,=()s
Where: S. Sliding distance at the specified initial sliding speed, m; specified initial sliding speed, km/h;
—actually measured initial sliding speed, km/h;
S——actually measured sliding distance, m.
10 Handling performance test
10.1 Test conditions
The determination of the front wheel side slip rate is carried out on a special test bench, and the rest is in accordance with the requirements of Article 3.1. 10.2 Instruments and equipment
Front wheel side slip test bench, steering angle meter, dynamometer and steel tape measure, etc. 10.3 Test method
10.3.1 Front wheel toe-in and side slip rate measurement
（16）
The front wheel toe-in measurement is carried out on a horizontal plane passing through the center of the left and right front wheels. Measure the difference between the front and rear distances in the symmetry plane of the left and right wheels. Measure once every time the wheel turns 90°, and take the average of four measurements. When measuring the front wheel side clearance rate, the test vehicle is in the lowest gear and drives in a straight line at a speed of about 4km/h. It passes the side slip test bench in the positive direction and reads the maximum side slip rate value displayed by the instrument when the front wheel passes. Repeat the measurement three times and take the minimum value. 10.3.2 Minimum turning circle diameter and horizontal passing diameter measurement The turning circle radius and horizontal passing radius refer to the distance from the outermost wheel track center and the outermost end point to the instantaneous turning axis when the test vehicle turns, that is, R and R in Figure 3..
Figure 3 Schematic diagram of turning circle diameter measurement (left turn) During the measurement, the vehicle under test drives steadily at a low speed, turns the steering wheel to the extreme position in one direction, and marks the tracks of the center and the outermost end of the outer wheel track on the ground. After driving a full circle, exit the site, and then use a steel tape measure to measure the diameter of the circle formed by the two rolling tracks. The measurement is evenly distributed three times and the average value is taken.
The measurement should be carried out in the two directions of turning left and turning right, and the average value is taken. 10.3.3 Driving Straightness Test
JB/T723594
Before the test, a 50m long prediction area and a 25m long measurement area are marked out on the test field in turn. During the test, the vehicle under test drives straight at a uniform speed of about 10km/h. When the center of its front wheel just reaches the starting line of the measurement area, the driver immediately releases the steering wheel with both hands and lets the vehicle under test drive freely until the center of any of its front wheels reaches the end line of the measurement area and stops. Measure the distance between the midpoint of the front axle and the extended line of the driving track of the midpoint of the front axle of the vehicle under test before it deviates from the starting line. Repeat the test three times and take the average of the three measurements. If the deviation direction is opposite in the three tests, the test is invalid and should be retested after inspection and adjustment, and the items affected by the adjustment should be retested. 10.3.4 Measurement of operating force
a. Measurement of steering wheel operating force
First, draw a driving route as shown in Figure 4 on the test site. During the measurement, the transport vehicle starts from point A at a speed of 10km/h, and drives its outer front wheel along curve ABCD. Measure the maximum operating force acting on the steering wheel during the driving of the vehicle under test from point B to point C. The measurement should be carried out three times in both right turn and left turn, and take the average value. When turning left, it should drive along a route symmetrical to Figure 4.
b Measurement of operating force of brake, clutch and other operating levers The measurement of the operating force of each operating mechanism is carried out using spring dynamometers of different types. During the measurement, the vehicle under test is in a stationary state. The minimum operating force required to smoothly move each operating mechanism to its working position is measured respectively. The force point is the midpoint of the driver's normal operating position. For the measurement of the operating force of the service brake pedal, see 12.3.2. A
BC concentric line and CD west center coordinates
Figure 4 Schematic diagram of driving trajectory for steering operating force measurement (right turn) 10.4 Test results and report
Record the results of each measurement and calculation and the driver's comments in Table 6. The slope rate in the table is the ratio of the offset to the length of the measuring area (or the vertical distance traveled).
11 Visual field measurement
11.1 Test conditions
11.1.1 The test site should be a sufficiently large and flat concrete or asphalt ground with a ground slope of no more than 1%. 11.1.2 The light in the test site should be dark enough so that the shadow of the obstruction of the vehicle under test can be shown on the ground during the test. 11.1.3 For adjustable driver's seats, they should be in the middle position of adjustment. 118
11.2 Instruments and equipment
Bulbs, bulb holders, steel tape measures, chalk, etc. 11.3 Test method
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11.3.1 On the test site, draw a semicircle with a radius of 12m with point M as the center as shown in Figure 5, and mark the center line NN. At the same time, draw a chord cd perpendicular to the NN line and 9.5m long, and draw a 1mX1m grid line 9.5m
Figure 5 Schematic diagram of the layout of the field of vision measurement
11.3.2 Use a driver's seat marking point measurement device that meets the requirements of GB6236 to measure the "eye position" of the driver of the test vehicle, that is, the purely theoretical eye position specified when determining the driver's field of vision. It is located 670mm above the driver's seat mark and 10mm in front.
11.3.3 Park the vehicle under test on the test field so that the projection of its "eye position" on the ground falls exactly on point M, and at the same time, the intersection of the longitudinal center plane of the vehicle under test with the ground is parallel to the NN line. 11.3.4 Use a bulb holder to fix two sufficiently bright (can cast a clear shadow on the ground) light bulbs with a spacing of 65mm above the driver's seat, and make the continuous midpoints of the two lights fall exactly on the driver's "eye position" specified in Article 11.3.2. The bulb holder shall not produce a shadow on the ground.
11.3.5 Turn on the light and adjust the bracket in turn so that the line connecting the two light sources is perpendicular to the line connecting the "eye position" and the obstructions (such as the cab frame, reflectors, etc.) in the front field of vision. Each time you aim at an obstruction, use chalk to draw the obstruction shadows of the components of the cab of the vehicle under test in the square on the ground. Then the vehicle under test is moved out of the test field, and the shadow image left on the ground is drawn on the coordinate paper in proportion. 11.3.6 During the day, a driver of medium build and normal vision sits in the driver's seat and looks at the left and right rearview mirrors of the vehicle under test (adjustment is allowed) to determine whether the scene on both sides of the vehicle under test and behind it can be seen clearly. 11.4 Test results and report
Record the test results in the table according to the requirements of Table 7, and attach a visual field diagram. The center distance α of the obscured shadow and its width 6 are both measured on the circumference of the chord length; when counting the number of obscured shadows within the range of the shaped visual field cd, incomplete shadows are counted as integers. 12 Braking performance test
12.1 Test conditions
12.1.1 The adhesion coefficient of the test road surface shall not be less than 0.7, and the longitudinal slope of the ramp parking test road shall be 20%. 12.1.2 In addition to the brake running-in during vehicle running-in, the vehicle should also be subjected to more than 10 emergency brake runs before this test.2 Use a driver's seat mark point measurement device that meets the requirements of GB6236 to determine the "eye position" of the driver of the test vehicle, that is, the purely theoretical eye position specified when determining the driver's field of vision. It is located 670mm above the driver's seat mark point and 10mm in front.
11.3.3 Park the test vehicle on the test field so that the projection of its "eye position" on the ground falls exactly on point M, and at the same time, the intersection line of the longitudinal center plane of the test vehicle with the ground is parallel to the NN line. 11.3.4 Use a bulb holder to fix two sufficiently bright (can cast a clear shadow on the ground) light bulbs with a spacing of 65mm above the driver's seat, and make the continuous midpoint of the two lights fall exactly on the driver's "eye position" specified in Article 11.3.2. The bulb holder shall not produce a shadow on the ground.
11.3.5 Turn on the light and adjust the bracket in turn so that the line connecting the two light sources is perpendicular to the line connecting the "eye position" and the obstructions (such as the cab frame, reflector, etc.) in the front field of vision. Each time you aim at an obstruction, use chalk to draw the obstruction shadows of the various components of the cab of the test vehicle in the square on the ground. Then move the test vehicle out of the test field and draw the shadow image left on the ground on the coordinate paper in proportion. 11.3.6 During the day, a driver of medium build and normal vision sits in the driver's seat and looks at the left and right rearview mirrors of the test vehicle (adjustment is allowed) to determine whether the scene on both sides of the test vehicle and behind it can be seen clearly. 11.4 Test results and report
Record the test results in the table according to the requirements of Table 7, and attach the field of vision diagram. The center distance α of the obstruction shadow and its width 6 are both measured on the circumference of the chord length; when counting the number of obstruction shadows within the range of the shaped field of vision cd, incomplete shadows are counted as integers. 12 Braking performance test
12.1 Test conditions
12.1.1 The adhesion coefficient of the test road surface shall not be less than 0.7, and the longitudinal slope of the ramp parking test road shall be 20%. 12.1.2 In addition to the brake running-in during the vehicle running-in, the emergency brake shall be applied more than 10 times before this test.2 Use a driver's seat mark point measurement device that meets the requirements of GB6236 to determine the "eye position" of the driver of the test vehicle, that is, the purely theoretical eye position specified when determining the driver's field of vision. It is located 670mm above the driver's seat mark point and 10mm in front.
11.3.3 Park the test vehicle on the test field so that the projection of its "eye position" on the ground falls exactly on point M, and at the same time, the intersection of the longitudinal center plane of the test vehicle with the ground is parallel to the NN line. 11.3.4 Use a bulb holder to fix two sufficiently bright (can cast a clear shadow on the ground) light bulbs with a spacing of 65mm above the driver's seat, and make the continuous midpoint of the two lights fall exactly on the driver's "eye position" specified in Article 11.3.2. The bulb holder shall not produce a shadow on the ground.
11.3.5 Turn on the light and adjust the bracket in turn so that the line connecting the two light sources is perpendicular to the line connecting the "eye position" and the obstructions (such as the cab frame, reflector, etc.) in the front field of vision. Each time you aim at an obstruction, use chalk to draw the obstruction shadows of the various components of the cab of the test vehicle in the square on the ground. Then move the test vehicle out of the test field and draw the shadow image left on the ground on the coordinate paper in proportion. 11.3.6 During the day, a driver of medium build and normal vision sits in the driver's seat and looks at the left and right rearview mirrors of the test vehicle (adjustment is allowed) to determine whether the scenery on both sides of the test vehicle and behind it can be seen clearly. 11.4 Test results and report
Record the test results in the table according to the requirements of Table 7, and attach the field of vision diagram. The center distance α of the obstruction shadow and its width 6 are both measured on the circumference of the chord length; when counting the number of obstruction shadows within the range of the shaped field of vision cd, incomplete shadows are counted as integers. 12 Braking performance test
12.1 Test conditions
12.1.1 The adhesion coefficient of the test road surface shall not be less than 0.7, and the longitudinal slope of the ramp parking test road shall be 20%. 12.1.2 In addition to the brake running-in during the vehicle running-in, the emergency brake shall be applied more than 10 times before this test.
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