Vehicle diesel engine gear abnormal noise hot test bench test system and test method

Abstract

The present invention relates to the technical field of automobile NVH testing, and discloses a vehicle diesel engine gear abnormal noise hot test bench test system, comprising a plurality of vibration collection devices installed on a diesel engine to be tested, the vibration collection device is connected to a signal processor via a noise signal cable, the signal processor is connected to an NVH measurement and control device, the NVH measurement and control device is also connected to a speed PID calculation module, the NVH measurement and control device is connected to a speed signal line, and the speed PID calculation module is connected to a throttle signal line. The present invention also discloses a test method for a vehicle diesel engine gear abnormal noise hot test bench test system. The vehicle diesel engine gear abnormal noise hot test bench test system and the test method thereof can realize rapid determination of the type of gear abnormal noise of a diesel engine assembly during factory hot test, and have a simple structure, low cost, and a convenient method.

Description

Technical Field

[0001] The invention relates to the technical field of automobile NVH testing, and in particular to a vehicle diesel engine gear abnormal noise hot test bench testing system and a testing method thereof. Background Art

[0002] With the development of automotive diesel engine technology, the design of transmission system has become more and more complex. Gear pairs are important transmission parts of diesel engines. Their abnormal transmission noise not only affects the user's sense of comfort, but also poses a greater quality risk to the reliability of the entire vehicle, becoming a prominent quality issue complained by customers.

[0003] At present, the quality control of diesel engine gear abnormal noise in the industry mainly relies on the processing accuracy and consistency of related parts and the assembly process, but the effect is not good. At the same time, factory hot tests generally rely on the operator's senses to judge. Due to the difference in personal senses and other noise factors (engine combustion noise, environmental background noise), the proportion of misjudgment, wrong judgment and missed judgment is high. Moreover, it is difficult to quickly and accurately judge the type of abnormal noise that occurs through sensory discrimination.

[0004] If the equipment is to be used to accurately and quantitatively determine the state of abnormal noise in diesel engine gears, there are currently two main methods: one is to use NVH test equipment to determine the diesel engine on a cold test bench under non-ignition and cold conditions. The problem with this method is that the diesel engine is running without ignition and cannot show the NVH level of the diesel engine transmission gear under actual operating conditions of the whole vehicle; the other method is to use non-standard acoustic instruments to check the possible location of the abnormal noise source under the condition of reducing background noise, and then analyze and confirm the abnormal noise type through the vibration spectrum. This method takes a lot of time to eliminate the interference of non-gear noise sources, and the operation process is complicated and the equipment is expensive. It cannot meet the factory hot test needs of large quantities of diesel engines. Summary of the invention

[0005] The purpose of the present invention is to address the deficiencies of the above-mentioned technology and provide a vehicle diesel engine gear abnormal noise hot test bench test system and a test method thereof, so as to realize rapid determination of the type of gear abnormal noise during the factory hot test of the diesel engine assembly, with simple structure, low cost and convenient method.

[0006] To achieve the above-mentioned purpose, the automotive diesel engine gear abnormal noise hot test bench test system designed by the present invention includes several vibration collection devices installed on the diesel engine to be tested, the vibration collection device is connected to a signal processor through a noise signal cable, the signal processor is connected to an NVH measurement and control device, the NVH measurement and control device is also connected to a speed PID calculation module, the NVH measurement and control device is connected to a speed signal line, and the speed PID calculation module is connected to a throttle signal line.

[0007] Preferably, the vibration collection device comprises an NVH vibration sensor connected to the noise signal cable, the NVH vibration sensor is screwed onto a transfer tool via threads, and the transfer tool is screwed onto a test portion of the diesel engine to be tested via threads.

[0008] Preferably, the NVH vibration sensor is a three-quadrant acceleration sensor.

[0009] A testing method of the vehicle diesel engine gear abnormal noise thermal test bench testing system comprises the following steps:

[0010] A) Setting test parameters: Before the diesel engine gear abnormal noise test, the test parameters are set in the NVH measurement and control equipment;

[0011] B) Establish standard specifications: The fully run-in diesel engine is tested on the factory hot test bench for at least 5 consecutive repeatability tests. The purpose of full running-in is to reduce the test differences caused by the changes in the initial transmission gear meshing characteristics of the diesel engine, obtain NVH data, and the standard deviation of the NVH sound intensity peak of each gear order does not exceed 1dB. On the basis that the NVH test repeatability meets the requirements, the standard specifications and failure sample database of gear abnormal noise are established;

[0012] C) Install the vibration collection device: After completing the oil and electrical connection work required for the factory hot test, install the vibration collection device near the transmission gear of the diesel engine to be tested;

[0013] D) Connecting the speed sensor and the throttle control module: connecting the speed sensor on the diesel engine to be tested to the speed signal line, and connecting the throttle control module on the diesel engine to be tested to the throttle signal line;

[0014] E) Constant operating condition NVH test: Start the diesel engine to be tested, complete the hot engine running-in and other test conditions, and then conduct the NVH constant operating condition test to obtain the NVH data and curve of the vibration-frequency band mode. The constant operating conditions are idling, low speed and medium speed;

[0015] F) NVH test under acceleration and deceleration conditions: Perform NVH acceleration and deceleration test to obtain NVH data and curves of speed-vibration mode;

[0016] G) Abnormal noise judgment: After the diesel engine to be tested undergoes an abnormal noise test, NVH data is obtained and compared with the standard specifications set in the NVH measurement and control equipment. If qualified, the engine will be removed from the production line. If unqualified, the engine will be compared with the sample data and curves in the failure sample database to determine which type of abnormal noise gear has the same characteristics. The location and type of the abnormal noise of the gear can be determined. According to the location and type of the abnormal noise of the gear, repair, assembly or parts control measures are taken, and then the test is returned to step E) to continue testing.

[0017] Preferably, in step A), the test parameters include speed conditions, test time, order, sampling frequency and FFT calculation parameters.

[0018] Preferably, in step B), establishing standard specifications comprises the following steps:

[0019] B1) replacing the diesel engine to be tested in step C) to step F) with a fully run-in diesel engine to obtain sample NVH characteristic data of the fully run-in diesel engine for evaluating the repeatability of the NVH test system, and obtaining sample NVH characteristic data of the diesel engine to be tested in step C) to step F on the basis that the NVH test system meets the repeatability requirements;

[0020] B2) Adopting the “mean ± 3 times standard deviation” method, select at least 50 sets of sample NVH characteristic data, and conduct statistics and analysis on the data of speed ranges or frequency ranges with obvious characteristics;

[0021] B3) Based on the diesel engine noise and vibration development goals and the consistency of sample NVH characteristic data, combined with sensory evaluation, establish the NVH standard specifications for qualified gear transmissions;

[0022] B4) setting the standard specifications in the automatic test program of the NVH measurement and control equipment according to the order characteristics of different transmission gears;

[0023] B5) Establish diesel engine samples with different types of abnormal noise gears, obtain corresponding failure NVH data, find abnormal characteristics, and establish NVH failure sample database.

[0024] Preferably, in the step C), the installation location of the vibration collection device includes the cylinder block side, the front end of the engine or the top of the cylinder head, the rear end of the engine or the top of the cylinder head.

[0025] Preferably, in the step F), when the NVH acceleration and deceleration condition test is performed, the acceleration and deceleration condition is set to test a point every X (rpm) from idle speed, increase to medium speed after a transition time T (s), and then gradually decrease to idle speed every X (rpm) and a transition time T (s), and the speed interval is set according to the speed control accuracy and stability.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] 1. The vibration collection device is small in size, easy and reliable to install, and can realize the collection of NVH vibration signals in more dimensions under the condition of arranging fewer vibration sensors. It can be applied to the disassembly and assembly links with high test efficiency requirements;

[0028] 2. The speed signal is collected by the speed sensor, transmitted to the NVH measurement and control equipment through the speed signal line to display the speed, and then transmitted to the speed PID calculation module. According to the set speed and throttle calibration mode, the voltage value required for throttle control is calculated. Through throttle control, the speed reaches an actual value. The speed sensor transmits the actual speed to the speed PID calculation module, and the voltage required for throttle control is adjusted by PID closed loop until the actual speed reaches the set speed. This structure is based on the diesel engine electronic control system to achieve precise speed control without the need to install additional speed acquisition devices. It has the characteristics of simple structure, fast response rate, and stable speed. It can automatically simulate the working conditions of the vehicle at uniform speed, acceleration and deceleration, thereby realizing NVH test functions under different working conditions;

[0029] 3. The test parameters can be set according to the rotation period and structural characteristics of the transmission gear, and the orders corresponding to different gears can be set. For example, the 106th order represents the NVH detection setting of the crankshaft drive gear (106 teeth). This method is specially set according to the transmission gear that may cause abnormal noise. It is highly targeted and can reduce the interference of background noise and eliminate the influence of non-gear noise frequency and order sources on NVH test results.

[0030] 4. The test conditions include constant and acceleration / deceleration conditions, which respectively simulate the sensory performance of the diesel engine gear transmission when the vehicle is driving at a constant speed and accelerating / decelerating. The constant speed setting can highlight the vibration characteristics of the transmission gear, making it easier to distinguish the gear abnormal noise from the background of noise not caused by the gear transmission. The acceleration / deceleration speed setting can cover the speed range where the gear transmission abnormal noise occurs.

[0031] 5. Standard specifications are set in the test program of NVH measurement and control equipment in the form of parameters such as NVH vibration limit, speed, frequency band, number of abnormal points, etc., which automatically determine whether it is qualified or not, and can be applied to factory hot tests with high automation and standardization requirements;

[0032] 6. Determination of abnormal noise type By establishing a failure sample database, it can be used to quickly identify the abnormal noise symptoms of different types of gears, and can provide specific reference solutions for diesel engine assembly process, parts quality control, and abnormal repair;

[0033] 7. The test system has a simple structure, low cost, and convenient method. It can quickly determine the type of abnormal noise and is suitable for factory hot tests of large quantities of diesel engines. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a structural schematic diagram of a thermal test bench test system for abnormal noise of a vehicle diesel engine gear of the present invention;

[0035] Figure 2 for Figure 1 A schematic diagram of the structure of the vibration collection device;

[0036] Figure 3 It is a flow chart of a test method of a test system for a thermal test bench for abnormal noise of a vehicle diesel engine gear of the present invention;

[0037] Figure 4 This is a schematic diagram of the comparison between NVH test results and gear noise sample data.

[0038] The components in the figure are numbered as follows:

[0039] Diesel engine to be tested 1, vibration collection device 2, noise signal cable 3, signal processor 4, NVH measurement and control equipment 5, speed PID calculation module 6, speed signal line 7, throttle signal line 8, NVH vibration sensor 9, adapter tooling 10, speed sensor 11, throttle control module 12. DETAILED DESCRIPTION

[0040] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0041] like Figure 1 As shown, the vehicle diesel engine gear abnormal noise hot test bench test system of the present invention includes a plurality of vibration collection devices 2 installed on the diesel engine 1 to be tested, the vibration collection device 2 is connected to the signal processor 4 through the noise signal cable 3, the signal processor 4 is connected to the NVH measurement and control equipment 5, the NVH measurement and control equipment 5 is also connected to the speed PID calculation module 6, the NVH measurement and control equipment 5 is connected to the speed signal line 7, and the speed PID calculation module 6 is connected to the throttle signal line 8.

[0042] Among them, Figure 2 As shown, the vibration collection device 2 includes an NVH vibration sensor 9 connected to a noise signal cable 3. The NVH vibration sensor 9 is screwed onto a transfer tool 10 through threads. The transfer tool 10 is screwed onto a test part of the diesel engine 1 to be tested through threads. The NVH vibration sensor 9 is a three-quadrant acceleration sensor.

[0043] When testing the abnormal noise thermal test bench test system for vehicle diesel engine gears in this embodiment, Figure 3 As shown, the following steps are included:

[0044] A) Setting test parameters: Before the diesel engine gear abnormal noise test, set the test parameters in the NVH measurement and control equipment 5;

[0045] B) Establish standard specifications: Perform repeatability tests on fully run-in diesel engines on factory hot test benches for at least 5 times to obtain NVH data. The standard deviation of the NVH sound intensity peak value for each gear order shall not exceed 1dB. On the basis that the NVH test repeatability meets the requirements, standard specifications for gear abnormal noise and a failure sample database shall be established;

[0046] C) Installing the vibration collection device: After completing the oil and electrical connection work required for the factory hot test, install the vibration collection device 2 near the transmission gear of the diesel engine 1 to be tested;

[0047] D) Connecting the speed sensor 11 and the throttle control module 12: Connecting the speed sensor 11 on the diesel engine 1 to be tested to the speed signal line 7, and connecting the throttle control module 12 on the diesel engine 1 to be tested to the throttle signal line 8;

[0048] E) Constant operating condition NVH test: Start the diesel engine to be tested, complete the hot engine running-in and other test conditions, and then conduct the NVH constant operating condition test to obtain the NVH data and curve of the vibration-frequency band mode. The constant operating conditions are idling, low speed and medium speed;

[0049] F) NVH test under acceleration and deceleration conditions: Perform NVH acceleration and deceleration test to obtain NVH data and curves of speed-vibration mode;

[0050] G) Abnormal noise determination: The diesel engine 1 to be tested undergoes abnormal noise test to obtain NVH data, such as Figure 4 As shown, it is compared with the standard specifications set in the NVH measurement and control equipment 5. If it is qualified, it will be removed from the production line. If it is unqualified, it will be compared with the sample data and curves in the failure sample database to determine which type of abnormal gear characteristics are consistent with. The location and type of the abnormal gear noise can be determined, and repair, assembly or parts control measures can be taken according to the location and type of the abnormal gear noise. Then, return to step E to continue testing.

[0051] Among them, in step A), the test parameters include speed conditions, test time, order, sampling frequency and FFT calculation parameters.

[0052] In step B), establishing standard specifications includes the following steps:

[0053] B1) replacing the diesel engine to be tested in step C) to step F) with a fully run-in diesel engine to obtain sample NVH characteristic data of the fully run-in diesel engine to evaluate the repeatability of the NVH test system, and obtaining sample NVH characteristic data of the diesel engine to be tested in step C) to step F on the basis that the NVH test system meets the repeatability requirements;

[0054] B2) Adopt the “mean ± 3 times standard deviation” method, select at least 50 sets of sample NVH characteristic data, and conduct statistics and analysis on the data of speed range or frequency range with obvious characteristics. For example, the obvious characteristic speed range of 86-order vibration is in the low and medium speed range;

[0055] B3) Based on the diesel engine noise and vibration development goals and the consistency of sample NVH characteristic data, combined with sensory evaluation, establish the NVH standard specifications for qualified gear transmissions;

[0056] B4) According to the order characteristics of different transmission gears, the standard specifications are set in the automatic test program of the NVH measurement and control equipment 5;

[0057] B5) Establish diesel engine samples with different types of abnormal gear noises, such as abnormal gear clearance, missing teeth, broken teeth, hard spots on the tooth surface, etc., obtain the corresponding failure NVH data, find abnormal characteristics, and establish an NVH failure sample database.

[0058] In step C), the installation parts of the vibration collection device 2 include the cylinder block side, the front end of the engine or the top of the cylinder head, and the rear end of the engine or the top of the cylinder head. Specifically, the cylinder block side corresponds to the balance shaft and the crankshaft transmission gear, the front end of the engine or the top of the cylinder head corresponds to the timing gear mechanism, and the rear end of the engine or the top of the cylinder head corresponds to the camshaft and the high-pressure oil pump transmission gear. The test range can include all the transmission gears of the diesel engine 1 to be tested.

[0059] In step F), when performing the NVH acceleration and deceleration condition test, the acceleration and deceleration condition is set to test a point every X (rpm) from idle speed, increase to medium speed after a transition time T (s), and then gradually decrease to idle speed every X (rpm) and a transition time T (s). The speed interval is set according to the speed control accuracy and stability.

[0060] The vehicle diesel engine gear abnormal noise hot test bench test system and test method of the present invention have a vibration collection device 2 with a small size, convenient and reliable installation, and under the condition of arranging fewer vibration sensors, more dimensional NVH vibration signal collection can be achieved, which can be applicable to the operation disassembly and assembly links with high test efficiency requirements; the speed signal is collected by the speed sensor 11, transmitted to the NVH measurement and control equipment 5 through the speed signal line 7 to display the speed, and transmitted to the speed PID calculation module 6, and the voltage value required for throttle control is calculated according to the set speed and throttle calibration mode. Through throttle control, the speed reaches an actual value, The speed sensor 11 transmits the actual speed to the speed PID calculation module 6, and performs PID closed-loop adjustment on the voltage required for throttle control until the actual speed reaches the set speed. This structure is based on the diesel engine electronic control system to achieve precise speed control without the need to install additional speed acquisition devices. It has the characteristics of simple structure, fast response rate, and stable speed. It can automatically simulate the working conditions of the vehicle at a constant speed, acceleration and deceleration, thereby realizing NVH test functions under different working conditions; the test parameters can be set according to the rotation period and structural characteristics of the transmission gear, and the orders corresponding to different gears can be set, such as 106 orders, The NVH detection setting represents the crankshaft drive gear (106 teeth). This method is specially set according to the transmission gear where abnormal noise may occur. It is highly targeted and can reduce the interference of background noise and eliminate the influence of non-gear noise frequency and order sources on NVH test results. The test conditions include constant and acceleration and deceleration conditions, which respectively simulate the sensory performance of diesel engine gear transmission when the whole vehicle is driving at a constant speed and acceleration and deceleration. The constant speed setting can highlight the vibration characteristics of the transmission gear, making it easier to distinguish the gear abnormal noise from the background of noise caused by non-gear transmission. The acceleration and deceleration speed setting can cover the speed range where the gear transmission abnormal noise occurs. range; standard specifications are set in the form of NVH vibration limit, speed, frequency band, number of abnormal points and other parameters in the test program of NVH measurement and control equipment 5, which automatically judges whether it is qualified or not, and can be applied to factory hot tests with high automation and standardization requirements; abnormal noise type determination can be applied to the rapid identification of abnormal noise symptoms of different types of gears by establishing a failure sample database, which can provide specific reference solutions for diesel engine assembly process, parts quality control, and abnormal repair; the test system has a simple structure, low cost, and convenient method, and can quickly determine the type of abnormal noise, which is suitable for factory hot tests of large quantities of diesel engines.

Claims

1. A test method for a vehicle diesel engine gear abnormal noise thermal test bench test system, characterized in that: A vehicle diesel engine gear abnormal noise hot test bench test system comprises a plurality of vibration collection devices (2) installed on a diesel engine to be tested (1), wherein the vibration collection devices (2) are connected to a signal processor (4) via a noise signal cable (3), the signal processor (4) is connected to an NVH measurement and control device (5), the NVH measurement and control device (5) is further connected to a speed PID calculation module (6), the NVH measurement and control device (5) is connected to a speed signal line (7), and the speed PID calculation module (6) is connected to a throttle signal line (8), and the test method comprises the following steps: A) Setting test parameters: before the diesel engine gear abnormal noise test, setting test parameters in the NVH measurement and control device (5); B) Establish standard specifications: Perform repeatability tests on fully run-in diesel engines on factory hot test benches for at least 5 times to obtain NVH data. The standard deviation of the NVH sound intensity peak value for each gear order shall not exceed 1dB. On the basis that the NVH test repeatability meets the requirements, standard specifications for gear abnormal noise and a failure sample database shall be established; C) Installing the vibration collection device: After completing the oil and electrical connection work required for the factory hot test, install the vibration collection device (2) at a position close to the transmission gear of the diesel engine to be tested (1); D) connecting the speed sensor (11) and the throttle control module (12): connecting the speed sensor (11) on the diesel engine to be tested (1) to the speed signal line (7), and connecting the throttle control module (12) on the diesel engine to be tested (1) to the throttle signal line (8); E) Constant operating condition NVH test: Start the diesel engine to be tested, complete the hot engine running-in and other test conditions, and then conduct the NVH constant operating condition test to obtain the NVH data and curve of the vibration-frequency band mode. The constant operating conditions are idling, low speed and medium speed; F) NVH test under acceleration and deceleration conditions: Perform NVH acceleration and deceleration test to obtain NVH data and curves of speed-vibration mode; G) Abnormal noise determination: The diesel engine to be tested (1) is subjected to abnormal noise test to obtain NVH data, which is compared with the standard specifications set in the NVH measurement and control equipment (5). If qualified, the engine is removed from the production line. If unqualified, the engine is compared with the sample data and curves in the failure sample database to determine which type of abnormal noise gear has the same characteristics. The location and type of the abnormal noise of the gear can be determined. According to the location and type of the abnormal noise of the gear, repair, assembly or parts control measures are taken, and then the process returns to step E) to continue testing.

2. The testing method of the vehicle diesel engine gear abnormal noise thermal test bench testing system according to claim 1 is characterized by: The vibration collection device (2) comprises an NVH vibration sensor (9) connected to the noise signal cable (3); the NVH vibration sensor (9) is screwed onto a transfer tool (10) via threads; and the transfer tool (10) is screwed onto a test portion of the diesel engine (1) to be tested via threads.

3. The testing method of the vehicle diesel engine gear abnormal noise thermal test bench testing system according to claim 2 is characterized by: The NVH vibration sensor (9) is a three-quadrant acceleration sensor.

4. The testing method of the vehicle diesel engine gear abnormal noise thermal test bench testing system according to claim 1 is characterized by: In step A), the test parameters include speed condition, test time, order, sampling frequency and FFT calculation parameters.

5. The testing method of the vehicle diesel engine gear abnormal noise thermal test bench testing system according to claim 1 is characterized by: In step B), establishing standard specifications includes the following steps: B1) replacing the diesel engine to be tested in step C) to step F) with a fully run-in diesel engine to obtain sample NVH characteristic data of the fully run-in diesel engine for evaluating the repeatability of the NVH test system, and obtaining sample NVH characteristic data of the diesel engine to be tested in step C) to step F on the basis that the NVH test system meets the repeatability requirements; B2) Adopting the "mean ± 3 times standard deviation" method, select at least 50 sets of sample NVH characteristic data, and conduct statistics and analysis on the data of speed ranges or frequency ranges with obvious characteristics; B3) Based on the diesel engine noise and vibration development goals and the consistency of sample NVH characteristic data, combined with sensory evaluation, establish the NVH standard specifications for qualified gear transmissions; B4) setting the standard specifications in the automatic test program of the NVH measurement and control equipment (5) according to the order characteristics of different transmission gears; B5) Establish diesel engine samples with different types of abnormal noise gears, obtain corresponding failure NVH data, find abnormal characteristics, and establish NVH failure sample database.

6. The testing method of the vehicle diesel engine gear abnormal noise thermal test bench testing system according to claim 1 is characterized by: In the step C), the installation location of the vibration collection device (2) includes the cylinder body side, the front end of the engine or the top of the cylinder head, the rear end of the engine or the top of the cylinder head.

7. The testing method of the vehicle diesel engine gear abnormal noise thermal test bench testing system according to claim 1 is characterized by: In the step F), when the NVH acceleration and deceleration condition test is performed, the acceleration and deceleration condition is set to test a point every X (rpm) from idle speed, increase to medium speed after a transition time T (s), and then gradually decrease to idle speed every X (rpm) and a transition time T (s). The speed interval is set according to the speed control accuracy and stability.

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