CN112903313B - Stability test method for heavy-duty car braking system - Google Patents

Abstract

The invention discloses a stability test method for a heavy-duty car braking system, which comprises the following steps: s1, preparing instruments required by a test: the system comprises a weather instrument, a speedometer, a data acquisition system, a pressure sensor, a temperature sensor, a gyroscope and a mass center platform; s2, testing conditions and related requirements of a test vehicle; s3, typical downhill braking stability test; s4, an emergency braking test. The stability test method is used for a heavy-duty car braking system in combination with a weather meter, a speedometer, a data acquisition system, a pressure sensor, a temperature sensor, a gyroscope and a mass center platform, is used for a special test for the braking stability of the heavy-duty car on a long downhill and a flat road in the test process, and is used for obtaining test data of a more comprehensive system through strict control of various parameters in the test process, so that the stability test method is more scientific and reasonable for later evaluation of the braking system of the heavy-duty car.

Description

Test method for stability of braking system of heavy vehicles

technical field

The invention relates to the technical field of automobile testing methods, in particular to a method for testing the stability of a heavy-duty automobile braking system.

Background technique

The current test methods for the braking system of automobiles are very basic, mainly testing the braking distance and braking time, which cannot objectively and effectively evaluate the performance of the vehicle braking system, which has great limitations. With the continuous improvement of vehicle braking requirements, especially for heavy-duty vehicles, there is still no complete and scientific test method system, resulting in unscientific and reasonable evaluation of heavy-duty vehicle braking systems.

Contents of the invention

The present invention aims to provide a scientific, reasonable and complete testing method for the stability of the braking system of heavy-duty vehicles.

For this reason, the technical scheme that the present invention adopts is: a kind of heavy-duty vehicle braking system stability test method, comprises the following steps:

S1. Preparation of instruments required for the test: including meteorological instrument, speedometer, data acquisition system, pressure sensor, temperature sensor, gyroscope, and center of mass platform; among them, the speedometer should be installed on the longitudinal symmetrical plane of the heavy vehicle, and the gyroscope should be close to the center of mass Install;

S2. Test conditions and relevant requirements of the test vehicle;

S2-1. Test road

S2-1-1. Long downhill test road, the length is not less than 5000m, the average width is not less than 5m, the average slope is not less than 10%, and the road surface is clean and dry;

S2-1-2. Flat test road with a length of not less than 2000m, a width of not less than 6m, a longitudinal slope of not more than 1%, and a transverse slope of not more than 2%. The road surface is clean and dry;

S2-2. Meteorological conditions

Atmospheric pressure 80~110kPa, wind speed less than 5m/s, temperature 5℃~35℃;

S2-3. Test vehicle and load

S2-3-1. The brake system of the test vehicle shall be a qualified product that meets the technical requirements of the product;

S2-3-2. The mileage of the test vehicle is less than 2000km, and the tire pressure is the cold inflation pressure recommended by the test vehicle manufacturer;

S2-3-3. The test vehicle is in the rated full load state specified by the manufacturer, and the load is evenly distributed and fixed to ensure that there will be no load transfer during the test. Use weighing equipment to weigh the test vehicle to ensure the wheel load difference of each axle The ratio is not greater than 5%; measure the wheelbase between each axle, measure the wheelbase of each axle, and measure the position of the center of mass of the vehicle;

S2-3-4. The test vehicle should run in the brakes;

S3. Typical downhill braking stability test;

S3-1. The test vehicle starts and accelerates to a speed of 30km/h~32km/h on a relatively flat road at the top of the slope and stabilizes for at least 5 seconds, then disengages the engine, and performs emergency braking at 30km/h±0.2km/h Until the test vehicle stops, record the test data;

S3-2. The test vehicle is driven downhill for a long distance, and the vehicle speed is controlled at 30±5km/h. The transmission gear used should ensure that the engine speed does not exceed the rated speed specified by the manufacturer, and record the test data;

S3-3. If one of the following situations occurs during the test, the test will be terminated: the temperature of the brake drum (disc) exceeds 400°C; the lateral acceleration is greater than 1m/s2; the vehicle speed cannot be controlled at 30±5km/h; the air pressure of the brake system is low at 500kPa;

S3-4. After the downhill test, the test vehicle starts quickly on a relatively flat road at the bottom of the slope and accelerates to a speed of 30km/h~32km/h and stabilizes for at least 5 seconds, then disengages the engine and runs at 30km/h±0.2km Carry out emergency braking at /h until the test vehicle stops, and record the test data;

S3-5. The measurement records include at least the average deceleration of each brake, the initial braking speed, the final braking speed, the temperature of the brake drum (disc), the pressure change of the air storage tank, the tire pressure and temperature before and after the test, Each braking time, time interval, vehicle longitudinal inclination, vehicle lateral inclination, lateral acceleration;

S4. Emergency brake test

S4-1. The test vehicle starts on a flat road and accelerates to a speed of 60km/h～62km/h and stabilizes for at least 5 seconds. Disengage the engine and perform emergency braking at 60km/h±0.2km/h until the test vehicle stops. Record test data;

S4-2. The test vehicle starts quickly on a flat road and accelerates to a speed of 60km/h~62km/h and stabilizes for at least 5 seconds, then disengages the engine; when the speed is 60km/h±0.2km/h, perform emergency braking to Release the emergency brake at 30km/h±5km/h, quickly accelerate the speed of the test vehicle to 60km/h～62km/h and stabilize it for at least 5 seconds, repeat the emergency brake-release emergency brake 50 times, the transmission gear used The position shall ensure that the engine speed does not exceed the rated speed specified by the manufacturer;

S4-3. During 50 emergency braking tests, if one of the following situations occurs, the test will be terminated: the braking distance is greater than 36m; the temperature of the brake drum (disc) exceeds 400°C; the deviation from the 3.5m wide lane; 1m/s2; brake system air pressure lower than 500kPa;

S4-4. After completing 50 emergency braking tests, the test vehicle accelerates rapidly on a flat road to a speed of 60km/h～62km/h and stabilizes for at least 5 seconds. Carry out emergency braking until the test vehicle stops, and record the test data;

S4-5. The measurement records include at least the average deceleration of each brake, the initial braking speed, the final braking speed, the temperature of the brake drum (disc), the change of the air pressure of the air tank, the tire pressure and temperature before and after the test, Each braking time, time interval, vehicle longitudinal inclination, vehicle lateral inclination, lateral acceleration.

As a preference for the above solution, in step S1, the measuring range of the meteorological instrument is: temperature: -10°C ~ 60°C; humidity: 0%RH ~ 100%RH; atmospheric pressure: 300hPa ~ 1200hPa; wind speed: 0.4m/s ~ 25m /s; the maximum error of the weather instrument: temperature: ±0.1℃; humidity: ±0.1%; atmospheric pressure: 0.1hPa; wind speed: 0.1m/s.

More preferably, in the step S1, the measurement range of the speedometer is: 0km/h～220km/h; the maximum error of the speedometer: speed 0.1km/h; speed output frequency: 200Hz; output mode: CAN, pulse.

Further preferably, in the step S1, the data acquisition system adopts 24 analog channels with scalable number, 16 digital inputs with scalable, and 2 CAN interfaces with scalable; working temperature: -10-55°C; channel precision: 0.1 %;

Single-channel maximum sampling frequency: 100kHz; single-channel AD: 24bit.

Further preferably, in the step S1, the measuring range of the pressure sensor is 0 bar to 15 bar; combined nonlinearity + hysteresis: ±0.5% FSmax; long-term stability: ±0.5% FS/year typ.

Further preferably, in the step S1, the measurement range of the temperature sensor is -41°C to 1000°C; the maximum error of the temperature sensor is ±1.5°C.

Further preferably, in the step S1, the gyroscope adopts high-performance nine-vector attitude measurement, and all signals are output at 200 Hz; acceleration range: ±18g; angular velocity range: ±300°/s; acceleration accuracy: 0.1m/s2; angular velocity accuracy : 0.1°/s; Angle accuracy: 0.1°; Speed accuracy: 0.1km/h.

More preferably, in the step S1, the table size of the center of mass platform is 12×3.3m; weighing range: 0-40000kg; angle range: 0-50°; weight accuracy: 5kg; angle accuracy: 0.5°.

Beneficial effects of the present invention: combined with meteorological instrument, speedometer, data acquisition system, pressure sensor, temperature sensor, gyroscope, and center-of-mass platform, it is used for the stability test of the braking system of heavy-duty vehicles. Conduct special tests on braking stability on slopes and flat roads, and through strict control of various parameters during the test process, more comprehensive and systematic test data can be obtained for subsequent evaluation of the stability of heavy-duty vehicle braking systems, which is more scientific ,Reasonable.

Detailed ways

Below by embodiment, the present invention will be further described:

A method for testing the stability of a heavy-duty vehicle braking system, comprising the following steps:

S1. Preparation of instruments required for the test: including meteorological instrument, speedometer, data acquisition system, pressure sensor, temperature sensor, gyroscope, and center of mass platform; among them, the speedometer should be installed on the longitudinal symmetrical plane of the heavy vehicle, and the gyroscope should be close to the center of mass Install;

The measuring range of the meteorological instrument is: temperature: -10℃～60℃; humidity: 0%RH～100%RH; atmospheric pressure: 300hPa～1200hPa; wind speed: 0.4m/s～25m/s;

The maximum error of the meteorological instrument: temperature: ±0.1℃; humidity: ±0.1%; atmospheric pressure: 0.1hPa; wind speed: 0.1m/s.

The measurement range of the speedometer is: 0km/h～220km/h; the maximum error of the speedometer: speed 0.1km/h; speed output frequency: 200Hz; output mode: CAN, pulse.

The digital acquisition system adopts 24 analog channels, 16 digital inputs, 2 CAN interfaces; working temperature: -10～55°C; channel accuracy: 0.1%;

Single-channel maximum sampling frequency: 100kHz; single-channel AD: 24bit.

The measuring range of the pressure sensor is 0bar to 15bar; combined nonlinearity + hysteresis: ± 0.5% FSmax; long-term stability: ± 0.5% FS/year typ.

The measuring range of the temperature sensor is -41°C to 1000°C; the maximum error of the temperature sensor is ± 1.5°C.

The gyroscope adopts high-performance nine-vector attitude measurement, and all signals are output at 200Hz; acceleration range: ±18g; angular velocity range: ±300°/s; acceleration accuracy: 0.1m/s2; angular velocity accuracy: 0.1°/s; angular accuracy: 0.1 °; speed accuracy: 0.1km/h.

The table size of the centroid platform is 12×3.3m; weighing range: 0~40000kg; angle range: 0~50°; weight accuracy: 5kg; angle accuracy: 0.5°.

As shown in Table 1.

Table 1 Measuring instrument measuring range and maximum error

S2. Test conditions and relevant requirements for test vehicles;

S2-1. Test road

S2-1-1. Long downhill test road, the length is not less than 5000m, the average width is not less than 5m, the average slope is not less than 10%, and the road surface is clean and dry;

S2-1-2. Flat test road with a length of not less than 2000m, a width of not less than 6m, a longitudinal slope of not more than 1%, and a transverse slope of not more than 2%. The road surface is clean and dry;

S2-2. Meteorological conditions

Atmospheric pressure 80~110kPa, wind speed less than 5m/s, temperature 5℃~35℃;

S2-3. Test vehicle and load

S2-3-1. The brake system of the test vehicle shall be a qualified product that meets the technical requirements of the product;

S2-3-2. The mileage of the test vehicle is less than 2000km, and the tire pressure is the cold inflation pressure recommended by the test vehicle manufacturer;

S2-3-3. The test vehicle is in the rated full load state specified by the manufacturer, and the load is evenly distributed and fixed to ensure that there will be no load transfer during the test. Use weighing equipment to weigh the test vehicle to ensure the wheel load difference of each axle The ratio is not greater than 5%; measure the wheelbase between each axle, measure the wheelbase of each axle, and measure the position of the center of mass of the vehicle;

S2-3-4. The test vehicle should run in the brakes;

S3. Typical downhill braking stability test;

S3-1. The test vehicle starts and accelerates to a speed of 30km/h~32km/h on a relatively flat road at the top of the slope and stabilizes for at least 5 seconds, then disengages the engine, and performs emergency braking at 30km/h±0.2km/h Until the test vehicle stops, record the test data;

S3-2. The test vehicle is driven downhill for a long distance, and the vehicle speed is controlled at 30±5km/h. The transmission gear used should ensure that the engine speed does not exceed the rated speed specified by the manufacturer, and record the test data;

S3-3. If one of the following situations occurs during the test, the test will be terminated: the temperature of the brake drum (disc) exceeds 400°C; the lateral acceleration is greater than 1m/s2; the vehicle speed cannot be controlled at 30±5km/h; the air pressure of the brake system is low at 500kPa;

S3-4. After the downhill test, the test vehicle starts quickly on a relatively flat road at the bottom of the slope and accelerates to a speed of 30km/h~32km/h and stabilizes for at least 5 seconds, then disengages the engine and runs at 30km/h±0.2km Carry out emergency braking at /h until the test vehicle stops, and record the test data;

S3-5. The measurement records include at least the average deceleration of each brake, the initial braking speed, the final braking speed, the temperature of the brake drum (disc), the pressure change of the air storage tank, the tire pressure and temperature before and after the test, Each braking time, time interval, vehicle longitudinal inclination, vehicle lateral inclination, lateral acceleration.

S4. Emergency brake test

S4-1. The test vehicle starts on a flat road and accelerates to a speed of 60km/h～62km/h and stabilizes for at least 5 seconds. Disengage the engine and perform emergency braking at 60km/h±0.2km/h until the test vehicle stops. Record test data;

S4-2. The test vehicle starts quickly on a flat road and accelerates to a speed of 60km/h~62km/h and stabilizes for at least 5 seconds, then disengages the engine; when the speed is 60km/h±0.2km/h, perform emergency braking to Release the emergency brake at 30km/h±5km/h, quickly accelerate the speed of the test vehicle to 60km/h～62km/h and stabilize it for at least 5 seconds, repeat the emergency brake-release emergency brake 50 times, the transmission gear used The position shall ensure that the engine speed does not exceed the rated speed specified by the manufacturer;

S4-3. During 50 emergency braking tests, if one of the following situations occurs, the test will be terminated: the braking distance is greater than 36m; the temperature of the brake drum (disc) exceeds 400°C; the deviation from the 3.5m wide lane; 1m/s2; brake system air pressure lower than 500kPa;

S4-4. After completing 50 emergency braking tests, the test vehicle accelerates rapidly on a flat road to a speed of 60km/h～62km/h and stabilizes for at least 5 seconds. Carry out emergency braking until the test vehicle stops, and record the test data;

S4-5. The measurement records include at least the average deceleration of each brake, the initial braking speed, the final braking speed, the temperature of the brake drum (disc), the change of the air pressure of the air tank, the tire pressure and temperature before and after the test, Each braking time, time interval, vehicle longitudinal inclination, vehicle lateral inclination, lateral acceleration. Explanation of technical terms:

(1) Longitudinal inclination—the angle of the vehicle's pitch (the angle of rotation around the y-axis).

(2) Lateral inclination—the angle at which the vehicle rolls (the angle of rotation around the x-axis).

(3) Longitudinal acceleration—acceleration in the direction of vehicle travel.

(4) Lateral acceleration—the component of the acceleration vector of the vehicle's center of mass (or sprung mass) along the y-axis.

(5) Emergency braking - when the vehicle encounters an emergency during driving, the driver quickly and fully actuates the brake pedal to stop the vehicle.

(6) Braking distance—the distance traveled by the vehicle from the moment the foot touches the brake pedal (or the hand touches the brake handle) to the moment the vehicle stops when the vehicle brakes suddenly at the specified initial speed.

(7) Wheel load difference ratio - the ratio of the absolute value of the difference between the left and right wheels on the same axle to the half of the axle load.

The braking stability test record sheet A1, the braking stability data analysis sheet A2, and the braking stability data analysis sheet A3 are shown below.

A1 Braking Stability Test Record Form

A2 braking stability data analysis table

A3 braking stability data analysis table

Claims (8)

1. The stability test method for the heavy-duty car braking system is characterized by comprising the following steps of:

s1, preparing instruments required by a test: the system comprises a weather instrument, a speedometer, a data acquisition system, a pressure sensor, a temperature sensor, a gyroscope and a mass center platform; the speedometer is arranged on a longitudinal symmetrical plane of the heavy vehicle, and the gyroscope is arranged close to the mass center;

s2, testing conditions and related requirements of a test vehicle;

s2-1, test road

S2-1-1, a long downhill test road, wherein the length is not less than 5000m, the average width is not less than 5m, the average gradient is not less than 10%, and the road surface is clean and dry;

s2-1-2, flattening a test road, wherein the length is not less than 2000m, the width is not less than 6m, the longitudinal gradient is not more than 1%, the transverse gradient is not more than 2%, and the road surface is clean and dry;

s2-2, meteorological Condition

Atmospheric pressure is 80-110 kPa, wind speed is less than 5m/s, and air temperature is 5-35 ℃;

s2-3, test vehicle and load

S2-3-1, testing a vehicle braking system, wherein the test vehicle braking system is a qualified product meeting the technical requirements of the product;

s2-3-2, wherein the driving distance of the test vehicle is less than 2000km, and the tire pressure is the cold inflation pressure recommended by the test vehicle manufacturer;

s2-3-3, wherein the test vehicle is in a rated full-load state specified by a manufacturer, loads are uniformly distributed and fixed, so that no load transfer occurs in the test, the test vehicle is weighed by a weighing device, and the wheel load difference ratio of each axle is ensured to be no more than 5%; measuring the wheel base among the shafts, measuring the wheel base of each shaft, and measuring the mass center position of the vehicle;

s2-3-4, the test vehicle should run in the brake;

s3, typical downhill braking stability test;

s3-1, starting and accelerating the test vehicle to a vehicle speed of 30 km/h-32 km/h on a road with a relatively flat slope top and stabilizing for at least 5 seconds, then disconnecting the engine, performing emergency braking when the speed of 30km/h +/-0.2 km/h until the test vehicle stops, and recording test data;

s3-2, performing long-distance downhill running on the test vehicle, controlling the speed of the vehicle to be 30+/-5 km/h, ensuring that the speed of an engine does not exceed the rated speed specified by a manufacturer by using a gear of a transmission, and recording test data;

s3-3, terminating the test when one of the following conditions occurs in the test process: the temperature of the brake drum or disc exceeds 400 ℃; lateral acceleration greater than 1m/s ² The method comprises the steps of carrying out a first treatment on the surface of the The speed of the vehicle cannot be controlled at 30+/-5 km/h; the brake system air pressure is lower than 500kPa;

s3-4, after the downhill test is finished, the test vehicle starts rapidly and accelerates to 30km/h 32km/h on a relatively flat road at the bottom of the slope and stabilizes for at least 5 seconds, then the engine is disconnected, emergency braking is carried out until the test vehicle stops at 30km/h +/-0.2 km/h, and test data are recorded;

s3-5, the measurement record at least comprises full average deceleration, initial braking speed, final braking speed, temperature of a brake drum or a brake disc, air pressure change of an air storage cylinder, air pressure and temperature of tires before and after a test, time of each braking, time interval, longitudinal inclination angle of a vehicle, transverse inclination angle of the vehicle and transverse acceleration;

s4, emergency braking test

S4-1, starting and accelerating the test vehicle to a vehicle speed of 60 km/h-62 km/h on a flat road, stabilizing for at least 5 seconds, disconnecting the engine, performing emergency braking when the speed of 60km/h +/-0.2 km/h until the test vehicle stops, and recording test data;

s4-2, rapidly starting and accelerating the test vehicle to a speed of 60 km/h-62 km/h on a flat road and stabilizing for at least 5 seconds, and disconnecting the engine; when the speed of the vehicle is 60 km/h+/-0.2 km/h, emergency braking is carried out until the speed reaches 30 km/h+/-5 km/h to release the emergency braking, the speed of the test vehicle is quickly accelerated to-62 km/h and stabilized for at least 5 seconds, the emergency braking is repeatedly carried out for 50 times, and the gear of the transmission is used for ensuring that the engine speed does not exceed the rated speed specified by the manufacturer;

s4-3, in 50 emergency braking tests, stopping the test when one of the following conditions occurs: the braking distance is more than 36m; the temperature of the brake drum or disc exceeds 400 ℃; deviation from 3.5m wide lane; lateral acceleration greater than 1m/s ² The method comprises the steps of carrying out a first treatment on the surface of the The brake system air pressure is lower than 500kPa;

s4-4, after 50 emergency braking tests are finished, the test vehicle is rapidly accelerated to a speed of 60 km/h-62 km/h on a flat road and stabilized for at least 5 seconds, the engine is disconnected, emergency braking is carried out until the test vehicle stops when 60km/h +/-0.2 km/h, and test data are recorded;

s4-5, the measurement record at least comprises the fully issued average deceleration of each braking, the initial braking speed, the final braking speed, the temperature of a brake drum or a brake disc, the air pressure change of an air storage cylinder, the air pressure and the temperature of tires before and after a test, and the time, the time interval, the longitudinal inclination angle, the transverse inclination angle and the transverse acceleration of each braking.

2. The method for testing the stability of a brake system of a heavy-duty car according to claim 1, wherein: in step S1, the measurement range of the weather meter is: temperature: -10 ℃ to 60 ℃; humidity: 0% RH-100% RH; atmospheric pressure: 300 hPa-1200 hPa; wind speed: 0.4 m/s-25 m/s;

maximum error of the weather instrument: temperature: (+ -0.1 ℃; humidity: + -0.1%; atmospheric pressure 0.1hPa; wind speed: 0.1m/s.

3. The method for testing the stability of a brake system of a heavy-duty car according to claim 1, wherein: in the step S1, the measuring range of the speedometer is: 0 km/h-220 km/h; maximum error of speedometer: speed 0.1km/h; speed output frequency: 200Hz; the output mode is as follows: CAN, pulse.

4. The method for testing the stability of a brake system of a heavy-duty car according to claim 1, wherein: in the step S1, the data acquisition system adopts 24 paths of extensible analog channel numbers, 16 paths of extensible digital quantity input and 2 paths of extensible CAN interfaces; operating temperature: -10-55 ℃; channel accuracy: 0.1%;

single channel highest sampling frequency: 100kHz; single channel AD is 24bit.

5. The method for testing the stability of a brake system of a heavy-duty car according to claim 1, wherein: in the step S1, the measuring range of the pressure sensor is 0 bar-15 bar; combining nonlinearity + hysteresis: 0.5% fsmax; long-term stability: 0.5% FS/year type.

6. The method for testing the stability of a brake system of a heavy-duty car according to claim 1, wherein: in the step S1, the measurement range of the temperature sensor is-41-1000 ℃; maximum error of temperature sensor ± 1.5 ℃.

7. The method for testing the stability of a brake system of a heavy-duty car according to claim 1, wherein: in the step S1, a gyroscope adopts high-performance nine-vector attitude measurement, and all signals are output at 200Hz; acceleration range: 18g; angular velocity range: 300 DEG/s; acceleration accuracy: 0.1m/s ² The method comprises the steps of carrying out a first treatment on the surface of the Angular velocity accuracy: 0.1 °/s; angular accuracy: 0.1 °; speed accuracy: 0.1km/h.

8. The method for testing the stability of a brake system of a heavy-duty car according to claim 1, wherein: in the step S1, the table surface size of the mass center platform is 12 multiplied by 3.3m; weighing range: 0-40000 kg; angular range: 0-50 degrees; weight accuracy: 5kg; angular precision: 0.5 deg..