Vehicle outside-vehicle passing noise testing method

Abstract

The invention relates to a method for testing passing noise outside a vehicle. The method is suitable for passing noise testing in the standard of GB1495-2020 Vehicle Accelerated Driving Exterior Noise Limit and Measurement Method. Equipment used in the invention is composed of an in-vehicle data acquisition host and a sound level meter, and is characterized in that a GNSS + IMU inertial navigation module is arranged in the in-vehicle data acquisition host, and the positions of an AA'line and a BB 'line, the speed of a test vehicle and the distance between the test vehicle and the AA'line and the BB' line in the standard of an automobile accelerated running out-of-vehicle noise limit value and measurement method are acquired through the inertial navigation module. The problems of measurement result deviation and data recording asynchronism caused by WIFI signal transmission time delay are solved.

Description

Technical Field

[0001] The present invention relates to a method for testing the passing noise outside a vehicle, which is applicable to the passing noise test in the standard of GB1495-2020 "Limits and Measurement Methods for Exterior Noise of Motor Vehicles during Acceleration". Background Art

[0002] Currently, the equipment used in the automotive industry for measuring the passing noise outside a vehicle during acceleration is as shown in Figure 1 When the test vehicle (1) passes the AA' line at the front, the digital trigger signal generated is transmitted to the external data acquisition host (3) outside the vehicle through a cable. The external data acquisition host (3) transmits the trigger signal to the in-vehicle data acquisition host (4) on the test vehicle (1) through the WIFI module (2). The in-vehicle data acquisition host (4) starts to record the instantaneous speed of the test vehicle (1) passing the AA' line and prompts the driver to start stepping on the accelerator to accelerate. When the rear of the test vehicle (1) passes the BB' line, a trigger signal is also sent to the in-vehicle data acquisition host (4) through the WIFI module (2). The in-vehicle data acquisition host (4) records the instantaneous speed at this time, and thus calculates the acceleration of the vehicle between the AA' line and the BB' line. The in-vehicle data acquisition host (4) transmits the test results such as speed, acceleration, throttle, and gear to the external data acquisition host (3) through the WIFI module (2). The external data acquisition host (3) simultaneously receives the noise measurement results of the sound level meter (5), and finally obtains the noise measurement results. The in-vehicle data acquisition host (4) generally consists of a central processing unit, a power supply module, a GPS module, a WIFI module, and an A / D acquisition module.

[0003] However, the current method for testing the passing noise outside the vehicle is complex. When the external data acquisition host (3) transmits the trigger signal to the in-vehicle data acquisition host (4) through the WIFI module (2), there is a time delay. When the in-vehicle data acquisition host (4) receives the trigger signal and records the instantaneous speed, in fact, the front of the test vehicle (1) has already passed the AA' line, and the recorded instantaneous speed has also changed. Similarly, there is also a certain time delay in the instantaneous recorded data when the rear of the test vehicle (1) passes the BB' line, resulting in the fact that it is not known whether the front and rear of the test vehicle (1) are really on the AA' line and the BB' line when recording the instantaneous speed, ultimately leading to deviations in the test results and asynchronization of the recorded data. Summary of the Invention

[0004] The present invention provides a testing method, and the composition of the testing equipment used is simple, as shown in Figure 2As shown in the figure: The device consists only of the in-vehicle data acquisition host (2) and the sound level meter (3). The in-vehicle data acquisition host (2) is built-in with a GNSS+IMU inertial navigation module, which can measure the absolute positions of line AA’ and line BB’ through the inertial navigation module, and can obtain the speed of the test vehicle (1) and the distances of the test vehicle (1) from line AA’ and line BB’ through the inertial navigation module. During the test, it is not necessary to obtain the trigger signal through the laser transmitter and the laser reflector, nor is it necessary to transmit the trigger signal through the WIFI signal. The states of the front of the test vehicle (1) passing line AA’ and the rear of the vehicle passing line BB’ can be accurately obtained, overcoming the problems of measurement result deviation and data recording asynchronism caused by the time delay of WIFI signal transmission.

[0005] At the same time, since the in-vehicle data acquisition host (2) is built-in with a video acquisition module, it can accurately record whether the instantaneous front and rear of the test vehicle are on the line when entering and leaving the line, and the reliability of the test results is higher.

[0006] Compared with the prior art, the beneficial effects of the test device of the present invention are: simple structure, low cost, convenient to carry and connect. There is no data transmission delay during the test process, and the test results are highly reliable. Description of the Drawings

[0007] Figure 1 Currently, the equipment used in the automotive industry to measure the external passing noise of a vehicle during acceleration. In the figure: 1. Test vehicle, 2. WIFI module, 3. External data acquisition host, 4. In-vehicle data acquisition host, 5. Sound level meter, 6. Laser transmitter, 7. Laser reflector.

[0008] Figure 2 The composition of the test device used in the present invention. In the figure: 1. Test vehicle, 2. In-vehicle data acquisition host, 3. Sound level meter.

[0009] Figure 3 The internal structure of the in-vehicle data acquisition host of the test device used in the present invention. In the figure: 1. Central processing unit, 2. Power supply module, 3. TTL pulse acquisition module, 4. Temperature acquisition module, 5. CAN communication module 6. GNSS+IMU inertial navigation module, 7. Video processing module, 8. A / D digital-to-analog acquisition module.

[0010] Figure 4 The interface of the in-vehicle data acquisition host of the device used in the present invention. In the figure: 1. Host origin, 2. GNSS antenna interface, 3. CAN interface, 4. Digital, analog quantity, temperature acquisition interface, 5. USB interface, 6. Power supply interface, 7. Video interface.

[0011] Figure 5The working process of the equipment used in the present invention. In the figure, 1. In-vehicle data acquisition host, 2. GNSS interface, 3. GNSS antenna, 4. CAN interface, 5. Digital, analog, and temperature acquisition interface, 6. Camera connection video interface, 7. Sound level meter, 8. Test vehicle. Detailed implementation manner

[0011] Figure 5 As shown, the equipment used in the present invention consists of an in-vehicle data acquisition host (1) and a sound level meter (7). The in-vehicle data acquisition host (1) is installed inside the vehicle. The GNSS antenna (3) is connected to the GNSS interface (2) of the in-vehicle data acquisition host (1) and is placed on the roof of the test vehicle (8). The CAN interface (4) is connected to the engine OBD CAN interface. Pressure, temperature, and sensors are connected to the digital, analog, and temperature acquisition interface (5) of the in-vehicle data acquisition host (1). The camera connection video interface (6) is installed at the front and rear of the test vehicle (8). The sound level meter (7) is installed at the designated position.

[0012] During the test, the GNSS+IMU inertial navigation module built into the in-vehicle data acquisition host (1) real-time collects the speed of the test vehicle (8) and the distances of the test vehicle (8) from the AA' line and the BB' line. When the front of the test vehicle (8) passes the AA' line and the rear of the test vehicle (8) passes the BB' line, the in-vehicle data acquisition host (1) can accurately measure the speed and status of the front and rear of the test vehicle (8) when crossing the line and prompt the driver to accelerate the vehicle. The sound level meter (7) records the noise value throughout the test process. At the same time, through the cameras installed at the front and rear of the vehicle, the in-vehicle data acquisition host (1) can synchronously record the video data of the front and rear of the test vehicle (8) when passing the AA' line and the BB' line to check the credibility of the test results.

[0013] The internal structure of the in-vehicle data acquisition host is as Figure 3As shown in the figure, it includes: a central processing unit (1), a power supply module (2), a TTL pulse acquisition module (3), a temperature acquisition module (4), a CAN communication module (5), a GNSS+IMU inertial navigation module (6), a video processing module (7), and an A / D data acquisition module (8). The difference from the current equipment used to test the passing noise outside the vehicle during acceleration is that there are an additional inertial navigation module and a video processing module. The central processing unit (1) collects and processes the data of all modules. The power supply module (2) supplies power to all modules. The TTL pulse acquisition module (3) acquires the engine speed signal. The temperature acquisition module (4) acquires the engine water temperature. The CAN communication module (5) reads the gearbox gear signal through the vehicle's OBD CAN interface. The GNSS+IMU inertial navigation module (6) can obtain the network RTK positioning enhancement signal through the 4G signal, and through differential operation, the in-vehicle data acquisition host (1) obtains a positioning accuracy of 1 cm. Thus, the positions of line AA' and line BB', the speed of the test vehicle, and the distances of the test vehicle from line AA' and line BB' are obtained. The video processing module (7) can synchronously view the actual situation of the front and rear of the vehicle passing through line AA' and line BB' during the test. The A / D data acquisition module (8) can acquire the intake pressure signal of the engine.

[0014] The external interfaces of the in-vehicle data acquisition host are as Figure 4 shown in the figure. The origin (1) is used to identify the positioning origin of the IMU. The GNSS antenna interface (2) is used to connect the GNSS antenna. The CAN interface (3) is used to connect the OBD CAN port of the vehicle. The digital, analog, and temperature acquisition interfaces (4) are used to connect pressure, speed, and temperature sensors. The USB interface (5) is used to connect to the computer. The power supply interface (6) is used to connect to the DC power supply. The video interface (7) is used to connect to the camera.

[0015] Since there is no need to transmit the trigger signal to the in-vehicle data acquisition host through the WIFI signal during the test, but the in-vehicle data acquisition host measures the distances of the test vehicle from line AA' and line BB' through the inertial navigation module, and then obtains the acceleration instruction. Such a structure overcomes the problem of measurement result deviation caused by the time delay of WIFI signal transmission. At the same time, since there is no out-of-vehicle data acquisition host, no laser emitter and laser reflector, the equipment structure is simple and portable.

Claims

1. A method for testing the passing-by noise outside a vehicle, characterized in that a GNSS+IMU inertial navigation module is built into the in-vehicle data acquisition host, and the positions of line AA’ and line BB’ in the standard of "Limits and Measurement Methods for Exterior Noise of Motor Vehicles during Acceleration" are obtained through the inertial navigation module.

2. An apparatus for testing the passing-by noise outside a vehicle according to claim 1, characterized in that a video acquisition module is built into the in-vehicle data acquisition host, and the situations of the vehicle head and the vehicle tail passing line AA’ and line BB’ are obtained through the video acquisition module.

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