Method and device for testing noise of engine piston

Abstract

The invention belongs to the technical field of engine detection, and particularly relates to an engine piston noise testing method and device, and the device comprises a detection box, an accelerator treading device, and a noise detector. The detection box is connected with the accelerator treading device and the noise detector, the detection box controls the accelerator treading device to work, and the noise detector transmits detected data into the detection box; a display screen, a key board and an arm ring are mounted on the detection box, and a main control module, a Bluetooth module and a rechargeable battery are arranged in the detection box; according to the scheme, the testing device can work by a single person, cooperation of multiple persons is not needed, the labor cost is saved, the testing efficiency is improved, and detection can be conveniently carried out in some scenes with limited persons; the arm ring is fixed on the arm and is tightened by the magic tape, so that the detection box is fixed on the arm, both hands of a worker are liberated, and other operations can be conveniently carried out in the detection process.

Description

Technical Field

[0001] The invention relates to the technical field of engine detection, and in particular to a method and a device for testing engine piston noise. Background Art

[0002] During normal engine operation, the piston reciprocates in the cylinder, producing sounds of a certain frequency and intensity. This is because the movement of the piston involves multiple mechanical actions, such as the piston sliding up and down on the cylinder wall, the friction between the piston ring and the cylinder wall, and the piston being pushed by the pressure of the combustion gas during the combustion stroke. The sounds produced by these normal mechanical movements are part of the normal working sound of the engine, and their frequency and loudness are relatively stable and usually within a reasonable range. For example, in a four-stroke engine, the piston produces regular sounds every time it completes a working cycle (including intake, compression, power and exhaust strokes). When the gap between the piston and the cylinder wall is too large, the piston swings in the cylinder or hits the cylinder wall, which will produce a crisp metal knocking sound, which is the so-called piston knocking sound; this sound is usually more obvious when the engine is idling or running at low speed; the reason for the excessive gap may be piston wear, cylinder wear or improper assembly of the piston and cylinder; for example, after a long period of engine operation, the piston skirt gradually wears due to friction, causing the matching gap between the piston and the cylinder wall to exceed the normal range; The appearance of piston noise is often accompanied by a decrease in engine power. If the piston noise is caused by the wear of the piston or related components, as the wear increases, the damage to the internal parts of the engine will be further expanded. Long-term piston noise without timely maintenance may significantly shorten the service life of the engine and may even cause the engine to malfunction. When producing new cars, engine testing is also an important inspection indicator, so professional equipment is required for targeted noise testing; however, the traditional method still uses a stethoscope or human ears for testing, which requires a high level of experience from engine testers, cannot be popularized on a large scale, and is not conducive to standardization. Therefore, we propose a test method and device for engine piston noise. Summary of the invention

[0003] The purpose of the present invention is to provide a method and device for testing engine piston noise to solve the problems raised in the above background technology.

[0004] To achieve the above object, the present invention provides the following technical solutions: a test device for engine piston noise, comprising a detection box, an accelerator pedal, and a noise detector; The detection box is connected to the accelerator pedal and the noise detector, the detection box controls the operation of the accelerator pedal, and the noise detector transmits the detected data to the detection box; the detection box is installed with a display screen, a keypad, and an arm ring, and the detection box is provided with a main control module, a Bluetooth module, and a rechargeable battery; The noise detector is provided with multiple parts, and the main body of the noise detector is composed of a suction cup, a mounting box, and a handle. The suction cup is located at the bottom and is attached to the engine cylinder of the engine piston when in use. The top of the suction cup is provided with a mounting box, and the top of the mounting box is provided with a handle by screws. A vibration sensor is installed at the bottom center of the suction cup, and the vibration sensor detects vibration data when the suction cup is attached to the engine cylinder. A collection microphone is installed on the top of the installation box, which is responsible for collecting the sound wave signal emitted by the engine. A rotating shaft is installed at the bottom of the collection microphone, and the direction of the collection microphone can be adjusted through the rotating shaft; a cable connection port is provided on one side of the top of the installation box, and a data cable is plugged into the cable connection port, and the other end of the data cable is connected to the detection box; The throttle pedal is composed of a mounting frame and a pedal rod. One end of the mounting frame is arranged in an arc shape so that the mounting frame can be abutted against the foot pedal of the cab. The other end of the mounting frame is movably connected with a telescopic member. A telescopic plate is arranged at one end of the telescopic member close to the mounting frame. Screw holes are equidistantly arranged on the top of the telescopic plate, and the screw holes are opened from top to bottom. A locking bolt is screwed on the top of the connection between the mounting frame and the telescopic member. The locking bolt fixes the mounting frame and the telescopic plate together downward. One end of the telescopic member abuts under the driver's seat. The upper left part of the mounting frame is symmetrically provided with adjustment slots, a remote control motor is installed on the left side of the front side of the mounting frame by bolts, a transmission end of the remote control motor extends into the inner cavity of the mounting frame, and a driving gear is installed on the transmission end of the remote control motor; A pedal rod is installed in the inner cavity of the mounting frame, and the pedal rod is composed of a sleeve, an adjustment rod, a sliding rod, and a gear plate; the gear plate is installed at the bottom of the sliding rod, and the gear plate is located directly above the driving gear, and the bottom of the gear plate is provided with gear teeth, and the gear teeth are downwardly meshed with the driving gear; A limited rotation rod is provided at the bottom of the sleeve, and the limited rotation rod is inserted on the right side of the mounting frame. The rotation of the sleeve is maintained by the limited rotation rod. An adjustment rod is sleeved on the limited rotation rod, and the left end of the adjustment rod is sleeved on the sliding rod. Both ends of the sliding rod are slidably inserted in the adjustment groove; A telescopic rod is arranged in the middle of the adjusting rod, so that the adjusting rod can be telescopically matched when the sliding rod is displaced. The adjusting rod on one side is arranged in a triangle, and one end of the triangular adjusting rod is fixed on the sleeve; a pedal is installed on the top of the sleeve, and the pedal is synchronously tilted with the sleeve and abuts against the accelerator pedal of the car; A gear plate is fixed in the middle of the bottom of the adjusting rod, and the driving gear drives the gear plate and the sliding rod to move. When the sliding rod moves, the adjusting rod is deformed. After the adjusting rod drives the sleeve to tilt, the pedal abuts against the accelerator pedal of the car. The depth of stepping on the accelerator is controlled by adjusting the inclination size of the sleeve. The accelerator size is controlled by stepping on the accelerator pedal of the car, and noise detection is cooperated. A fixing bolt is set in the middle of the sliding rod. The fixing bolt passes through the sliding rod and is screwed on the gear plate, which is convenient for disassembly of the gear plate.

[0005] Preferably, the armband is symmetrically mounted on the bottom of the detection box, and the armband is sleeved on the arm for use, and a Velcro strap is provided on the outside of the armband to tighten the armband.

[0006] Preferably, a remote-controlled telescopic motor is installed in the inner cavity of the sleeve, and a downwardly extending sleeve rod is provided at the bottom of the pedal, the sleeve rod is inserted in the sleeve, and the transmission end of the remote-controlled telescopic motor is upwardly fixed to the bottom of the sleeve rod. The pedal is driven to telescope and move through the extension of the remote-controlled telescopic motor, and the length of the pedal is changed through the telescopic movement, which is convenient for adapting to the height of different car accelerator pedals. The telescopic range of the pedal does not exceed the length of the sleeve rod.

[0007] Preferably, a tilt sensor is embedded in the downward side of the outer wall of the sleeve to detect the tilt angle of the sleeve to monitor the accelerator pedaling depth; a rechargeable battery and a Bluetooth module are also provided in the accelerator pedal, and the accelerator pedal is connected to the Bluetooth module in the detection box via the Bluetooth module to transmit the tilt angle of the accelerator pedal detected by the tilt sensor.

[0008] Preferably, the detection box establishes a connection with the noise detector through the Bluetooth communication protocol, and a rechargeable battery is also provided in the installation box of the noise detector. A charging port is provided on the other side of the top of the installation box, and the rechargeable battery is replenished with electric energy through the charging port; a signal acquisition module and a Bluetooth module are provided in the noise detector, and a Bluetooth module is also provided in the inner cavity of the detection box, and the Bluetooth module in the detection box is provided with multiple Bluetooth channels, and the detection box is interconnected with the Bluetooth modules of multiple noise detectors through the Bluetooth channels and transmits detection information.

[0009] Preferably, a single person can perform the test work using the test device, and multiple noise detectors are arranged along the piston working position on the main thrust side of the engine cylinder body, and vibration signals and sound wave signals of the piston during operation are collected through vibration. Since multiple noise detectors are provided, they can be distributed in sequence along the position of the piston, or a single piston range can be selected for detection.

[0010] A test method for a test device for engine piston noise: S1, arrangement of noise detectors: multiple noise detectors are arranged along the working position of the piston on the main thrust side of the engine cylinder body, and vibration signals and sound wave signals of the piston when it is running are collected through vibration. Since multiple noise detectors are provided, they can be distributed in sequence along the position of the piston, or a single piston range can be selected for detection; The installation position of the noise detector is selected in the middle of the upper half of the main thrust side of the engine cylinder, mainly collecting vibration signals; the middle position from the crankshaft pulley end to the flywheel end, which is generally 10-12cm away from the cylinder in the main thrust direction, mainly collecting sound wave signals; S2, test steps: place the accelerator pedal on the accelerator pedal of the car, and then control the accelerator pedal to keep the accelerator of the car constant; the detection box controls the remote control motor and the remote control telescopic motor to complete the specified action; the remote control motor drives the driving gear and the gear plate to move, so as to achieve the displacement and tilt of the pedal rod, so that the pedal can abut on the accelerator pedal of the car, and the depth of the accelerator is controlled by adjusting the inclination angle of the sleeve, so as to achieve the control of the accelerator size; the accelerator pedal is also equipped with a remote control telescopic motor, which can adjust the length of the pedal as needed to adapt to the height of different car accelerator pedals; The detection box establishes a Bluetooth communication connection with the accelerator pedal through the Bluetooth module, and is responsible for receiving the tilt angle data transmitted by the accelerator pedal in real time; at the same time, the detection box is also connected to the noise detector through Bluetooth to receive the vibration and sound wave signals collected by the noise detector; these data are further analyzed and processed by the microprocessor in the detection box to determine whether there is piston noise in the engine; S3, test principle: use the minimum time interval of the engine crankshaft signal as the unit of measurement to determine the moment when the peak value of the vibration signal exceeds the peak limit and the moment when the sound wave reaches the peak value; calculate the difference in the piston interval moments, if the difference does not exceed the preset moment difference, then it is judged that the moment is within the preset moment range; if the moment is within the preset moment range, it is determined that the engine has piston noise.

[0011] Compared with the prior art, the present invention has the following beneficial effects: The test device of this solution can be operated by one person alone without the need for collaboration of multiple people, thus saving labor costs and improving test efficiency, making it convenient to carry out tests even in some scenarios with limited personnel. The test box is fixed on the arm through an armband and fastened with a Velcro strap, thereby freeing the hands of the staff and facilitating other operations during the test process. The noise detector can be flexibly arranged to detect the piston conditions of different parts of the engine in a more targeted manner. At the same time, the noise sensor has two optional connection methods: wireless and wired. The cable connection method can make the detection data smoother, while the wireless connection can achieve wireless restraint, which provides more construction space during engine testing. By setting a vibration sensor on the noise detector to collect vibration signals and a microphone to collect sound wave signals, the running status of the engine piston can be monitored from multiple angles, and the working condition of the engine piston and whether there are abnormal noise and other problems can be judged more comprehensively and accurately; The accelerator pedal can remotely control the throttle of the car. During the test, the staff does not need to directly operate the throttle manually. The throttle size can be flexibly adjusted according to the test requirements at a certain distance. It is convenient and safe, and does not require the assistance of others. It is also convenient to cooperate with other test operations simultaneously. The detection box can perform in-depth analysis and processing on the received data, such as drawing trend graphs, spectrum graphs, histograms, etc. of the vibration signal. It can present abstract data to the staff in an intuitive graphical manner, allowing them to understand the changes in vibration more intuitively, helping to quickly determine the working status of the engine piston and whether there are any abnormalities, and facilitating the standardized operations of the staff. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of cable connection of the present invention; Figure 2 This is a remote connection schematic diagram of the present invention; Figure 3 This is a schematic diagram of the accelerator pedal of the present invention; Figure 4 It is a structural diagram of the pedal rod of the present invention; Figure 5 This is a schematic diagram of the gear plate adjustment of the present invention; Figure 6 This is a schematic diagram of stepping on the pedal of the present invention; Figure 7 is a first schematic diagram of a noise detector of the present invention; Figure 8 is a second schematic diagram of the noise detector of the present invention; Fig. 9 This is a schematic diagram of the installation of the vibration sensor of the present invention.

[0013] In the figure: 10 detection box; 101 arm ring; 102 keypad; 103 display screen; 20 throttle pedal; 201 mounting frame; 202 telescopic member; 203 locking bolt; 204 adjusting slot; 205 remote control motor; 206 driving gear; 207 pedal rod; 2071 sleeve; 2072 remote control telescopic motor; 2073 pedal; 2074 adjustment rod; 2075 limit rotation rod; 2076 sliding rod; 2077 gear plate; 2078 fixing bolt; 2079 tilt sensor; 30 noise detector; 301 vibration sensor; 302 charging port; 303 collection microphone; 304 cable connection port. DETAILED DESCRIPTION

[0014] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0015] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. Example

[0016] See also Figure 1-9 , the present invention provides a method and device for testing engine piston noise, including a detection box 10, an accelerator pedal 20, and a noise detector 30; The detection box 10 is connected to the accelerator pedal 20 and the noise detector 30. The detection box 10 controls the accelerator pedal 20 to work, and the noise detector 30 transmits the detected data to the detection box 10. The detection box 10 is equipped with a display screen 103, a keypad 102, and an armband 101. The detection box 10 is provided with a main control module (the main control module includes any one of a single-chip microcomputer, a microprocessor, and a control chip), a Bluetooth module, and a rechargeable battery. The armband 101 is symmetrically installed at the bottom of the detection box 10, and the armband 101 is sleeved on the arm for use. A Velcro band is provided on the outside of the armband 101 to tighten the armband 101. The detection box 10 can be fixed on the arm through the armband 101, freeing the hands of the staff; The noise detector 30 is provided with multiple parts. The main body of the noise detector 30 is composed of a suction cup, a mounting box, and a handle. The suction cup is located at the bottom and is attached to the engine cylinder of the engine piston when in use. The top of the suction cup is provided with a mounting box, and the top of the mounting box is provided with a handle by screws. A vibration sensor 301 is installed at the bottom center of the suction cup. The vibration sensor 301 detects vibration data as the suction cup is attached to the engine cylinder. A collection microphone 303 is installed on the top of the installation box. The collection microphone 303 is responsible for collecting the sound wave signal emitted by the engine. A rotating shaft is installed at the bottom of the collection microphone 303. The collection microphone 303 can adjust its direction through the rotating shaft. A cable connection port 304 is provided on one side of the top of the installation box. A data cable is plugged into the cable connection port 304. The other end of the data cable is connected to the detection box 10. The throttle pedal 20 is composed of a mounting frame 201 and a pedal rod 207. One end of the mounting frame 201 is arranged in an arc shape, so that the mounting frame 201 can be easily connected to the foot pedal of the cab. The other end of the mounting frame 201 is movably connected with a telescopic member 202. The telescopic member 202 is provided with a telescopic plate at one end close to the mounting frame 201. Screw holes are equidistantly provided on the top of the telescopic plate, and the screw holes are opened from top to bottom. A locking bolt 203 is screwed on the top of the connection between the mounting frame 201 and the telescopic member 202. The locking bolt 203 fixes the mounting frame 201 and the telescopic plate together downward. One end of the telescopic member 202 is abutted under the driver's seat. An adjustment slot 204 is symmetrically provided on the upper left side of the mounting frame 201. A remote control motor 205 is installed on the left side of the front side of the mounting frame 201 by bolts. The transmission end of the remote control motor 205 extends into the inner cavity of the mounting frame 201, and a driving gear 206 is installed on the transmission end of the remote control motor 205. A pedal rod 207 is installed in the inner cavity of the mounting frame 201, and the pedal rod 207 is composed of a sleeve 2071, an adjustment rod 2074, a sliding rod 2076, and a gear plate 2077; the gear plate 2077 is installed at the bottom of the sliding rod 2076, and the gear plate 2077 is located directly above the driving gear 206, and the bottom of the gear plate 2077 is provided with gear teeth, and the gear teeth are downwardly meshed with the driving gear 206; A limited rotation rod 2075 is provided at the bottom of the sleeve 2071, and the limited rotation rod 2075 is inserted into the right side of the mounting frame 201, and the rotation of the sleeve 2071 is maintained by the limited rotation rod 2075. An adjusting rod 2074 is sleeved on the limited rotation rod 2075, and the left end of the adjusting rod 2074 is sleeved on the sliding rod 2076, and the two ends of the sliding rod 2076 are slidably inserted in the adjusting slot 204; A telescopic rod is arranged in the middle of the adjusting rod 2074, so that the adjusting rod 2074 can be telescopically matched when the sliding rod 2076 is displaced. The adjusting rod 2074 on one side is arranged in a triangle, and one end of the triangular adjusting rod 2074 is fixed on the sleeve 2071; a pedal 2073 is installed on the top of the sleeve 2071, and the pedal 2073 is synchronously tilted with the sleeve 2071 and abuts against the accelerator pedal of the car; A gear plate 2077 is fixed in the middle of the bottom of the adjusting rod 2074, and the driving gear 206 drives the gear plate 2077 and the sliding rod 2076 to move. When the sliding rod 2076 moves, the adjusting rod 2074 is deformed. After the adjusting rod 2074 drives the sleeve 2071 to tilt, the pedal 2073 abuts against the accelerator pedal of the car. The depth of stepping on the accelerator is controlled by adjusting the tilt size of the sleeve 2071. The accelerator size is controlled by stepping on the accelerator pedal of the car through the accelerator pedal 20, and the noise detection is coordinated; A fixing bolt 2078 is provided in the middle of the sliding rod 2076. The fixing bolt 2078 penetrates the sliding rod 2076 and is screwed to the gear plate 2077, so as to facilitate the disassembly of the gear plate 2077. A tilt sensor 2079 is embedded in the downward side of the outer wall of the sleeve 2071 to detect the tilt angle of the sleeve 2071 to monitor the accelerator pedal depth; The inner cavity of the sleeve 2071 is equipped with a remote control telescopic motor 2072, and the bottom of the pedal 2073 is provided with a sleeve rod extending downward, which is inserted into the sleeve 2071, and the transmission end of the remote control telescopic motor 2072 is upwardly fixed to the bottom of the sleeve rod. The extension of the remote control telescopic motor 2072 drives the pedal 2073 to telescope, and the length of the pedal 2073 is changed by telescopic movement, so as to adapt to the height of different automobile accelerator pedals. The telescopic range of the pedal 2073 does not exceed the length of the sleeve rod. The detection box 10 establishes a connection with the noise detector 30 through the Bluetooth communication protocol. A rechargeable battery is also provided in the installation box of the noise detector 30. A charging port 302 is provided on the other side of the top of the installation box, and the rechargeable battery is replenished with electric energy through the charging port 302. A signal acquisition module and a Bluetooth module are provided in the noise detector 30. A Bluetooth module is also provided in the inner cavity of the detection box 10, and the Bluetooth module in the detection box 10 is provided with multiple Bluetooth channels. The detection box 10 is interconnected with the Bluetooth modules of multiple noise detectors 30 through the Bluetooth channels and transmits detection information. A rechargeable battery and a Bluetooth module are also provided in the accelerator pedal 20 . The accelerator pedal 20 is connected to the Bluetooth module in the detection box 10 via the Bluetooth module to transmit the inclination angle of the accelerator pedal 20 detected by the inclination sensor 2079 .

[0017] The remote control motor 206 and the remote control telescopic motor 2072 are both Bluetooth remote controls (the motors and telescopic machines that can achieve Bluetooth connection and control in the market can be used), and the detection box 10 establishes a Bluetooth communication connection with the remote control motor 206 and the remote control telescopic motor 2072 through the Bluetooth module; the noise detector 30 preferably has two types of cable connection and Bluetooth connection, and when the cable connection is selected, the cable connection port 304 is used; A cable connection port 304 is also provided on the detection box 10. When a noise detector 30 connected by a cable is selected, the noise detector 30 is provided with power from the detection box 10 by the cable, and data transmission is completed through the cable. When a noise detector 30 connected by Bluetooth is selected, the detection box 10 and the noise detector 30 are connected by Bluetooth communication, and wireless data transmission is realized within a short distance, which is very convenient.

[0018] The detection principle is as follows: the noise detector 30 is provided with a vibration sensor 301 (collecting vibration signals) and a collection microphone 303 (collecting sound wave signals). The inductive crystals of the vibration sensor 301 and the collection microphone 303 will generate electric charges when subjected to mechanical stress, and the microstructure of the detection element will be displaced or deformed due to the vibration, and these physical changes will be converted into electrical signals. A signal processing module is provided in the noise detector 30, and the signal processing module amplifies, filters, and performs analog-to-digital conversion on these original electrical signals. The amplification circuit amplifies the weak electrical signal to an amplitude suitable for subsequent processing; the filtering circuit can remove high-frequency noise and low-frequency interference in the signal to improve the signal quality; the analog-to-digital conversion circuit converts the analog signal into a digital signal for digital processing and transmission; A microprocessor or chip is provided inside the noise detector 30, which can run some simple algorithms to perform preliminary analysis on the collected data; for example, calculate basic statistical parameters such as the peak value, mean value, and variance of the vibration signal, or convert the vibration signal in the time domain to the frequency domain through a fast Fourier transform (FFT) to analyze the frequency components of the signal to determine the main frequency range and energy distribution of the vibration; The vibration sensor 301 and the collection microphone 303 send the collected and preliminarily analyzed data to the paired detection box 10 through the Bluetooth wireless communication protocol, and the Bluetooth module in the detection box 10 decodes the data received; the detection box 10 is also provided with a microprocessor and a built-in program system for analysis. These software can perform more in-depth analysis and processing on the received data; for example, trend graphs, spectrum graphs, histograms, etc. of the vibration signal are drawn and displayed on the display screen 103, so that the staff can understand the changes in vibration more intuitively, which is very convenient.

[0019] There are various buttons on the keypad 102 provided on the detection box 10. When a worker presses a certain button, the detection box 10 detects the operation and outputs a command signal, including a command button for controlling the remote control motor 205 and the remote control telescopic motor 2072. The control commands of the remote control motor 205 include on, off, forward and reverse rotation, and the control commands of the remote control telescopic motor 2072 include on, off, telescopic rotation; The accelerator pedal 20 has a built-in rechargeable battery, a microprocessor, and a Bluetooth module. The Bluetooth module establishes a Bluetooth communication connection with the detection box 10. The internal microcontroller (chip) converts the key operation into a specific digital instruction according to a preset program; the generated digital instruction is encoded and transmitted via Bluetooth technology, and the modulation is to load the encoded signal onto a high-frequency carrier for transmission in a wireless environment. Commonly used Bluetooth modulation methods include Gaussian frequency shift keying (GFSK), etc. The encoded and modulated signal is transmitted through the Bluetooth module on the detection box 10 and is executed by the remote control motor 205 or the remote control telescopic motor 2072 to achieve the purpose of remotely controlling the car throttle. The noise test method is as follows: The test device can be used by a single person to perform the test work. First, multiple noise detectors 30 are arranged along the working position of the piston on the main thrust side of the engine cylinder body, and the vibration signal and the sound wave signal of the piston when it is running are collected by vibration. Since multiple noise detectors 30 are provided, they can be distributed in sequence along the position of the piston, or the piston range can be selected separately for detection; The preferred arrangement positions of the noise detector 30 are: in the middle of the upper half of the main thrust side of the engine's cylinder body, mainly collecting vibration signals; in the middle of the crankshaft pulley end to the flywheel end, which is generally 10-12 cm away from the cylinder body in the main thrust side direction, mainly collecting sound wave signals. Test method 1: With the piston interval as a reference point, place the accelerator pedal 20 on the accelerator pedal of the car, then control the accelerator pedal 20 to keep the throttle of the car constant, and use the minimum time interval of the engine crankshaft signal as a measurement unit to determine the time when the peak value of the vibration signal exceeds the peak limit and the time when the sound wave reaches the peak value; calculate the difference in the piston interval time, if the difference does not exceed the preset time difference, then it is judged that the time is within the preset time range; if the time is within the preset time range, it is determined that the engine has piston noise; Select the minimum time interval of the engine crankshaft signal as the unit of measurement; use this unified measurement standard to accurately find the specific moment when the peak value of the vibration signal exceeds the pre-set peak limit, and also determine the specific moment when the sound wave reaches its peak value; this step is to provide basic data for subsequent analysis and clarify the time point when the relevant physical quantities (vibration, sound waves) appear in a critical state (reaching the peak value); After determining the above two moments (the moment when the vibration signal peak exceeds the limit and the moment when the sound wave peaks), the time difference corresponding to the piston interval needs to be calculated; the piston interval moment mentioned here should be a specific moment related to the piston movement and associated with the two moments determined above; If the calculated difference does not exceed the preset time difference, it means that the current time of interest is within a preset specific time range; this preset time range is determined in advance based on the study and definition of normal engine operation and possible piston noise. When, through the previous calculation and judgment, it is determined that the time is within the preset time range, it can be determined that piston noise occurs in the engine. Test method 2: With the piston interval as the reference point and the engine speed as the measurement unit, the accelerator pedal 20 is placed on the accelerator pedal of the car, and then the accelerator pedal 20 is controlled to adjust the throttle of the car, and the vibration and sound wave changes of the engine are detected by the noise detector 30. If the vibration and sound wave are significantly weakened or disappear in a certain piston interval at a certain speed, it means that there is a piston abnormality problem in the engine cylinder at that location; The engine speed is an important parameter to measure the working state of the engine. It reflects the number of revolutions per minute of the engine crankshaft, and the unit is usually revolutions per minute (rpm). This means that during the entire testing process, the engine speed change should be used as a reference standard, such as observing and testing at different speeds (such as 1000rpm, 2000rpm, etc.); The purpose of controlling the throttle of a car is to change the speed of the engine. The opening of the throttle directly affects the amount of fuel and air entering the engine cylinder, thereby changing the output power and speed of the engine. By adjusting the throttle, the engine can be operated in different speed ranges, so as to comprehensively detect the state of the engine under various working conditions. Use noise detectors to detect changes in engine vibration and sound waves; when the engine is working normally, it will generate vibration and sound waves of a certain frequency and intensity, which are caused by the reciprocating motion of the piston, the opening and closing of the valve, the combustion of fuel, and other factors; The key point is that during the detection process, if at a specific engine speed, in a certain piston range (a specific range of movement of the piston in the cylinder, such as the range from the top dead center to the bottom dead center of the piston), it is found that vibration and sound waves are significantly weakened or disappear; under normal circumstances, the piston will continue to generate vibration and sound waves when moving in the cylinder. When these signals change significantly (weaken or disappear) in a certain piston range, it means that the working state of the piston in the cylinder corresponding to this range of the engine has become abnormal; this abnormality may be caused by piston wear, piston ring damage, excessive gap between the piston and the cylinder wall, etc., because these problems will change the vibration and sound wave characteristics generated by the piston movement.

[0020] In addition, the above two test methods can also be used to shut down the engine, remove the spark plug of the cylinder suspected of having noise, inject a small amount of engine oil into the cylinder above the piston, and then turn the crankshaft several times. Then install the spark plug and start the engine for testing. If the vibration or sound wave detection is still weakened or disappears after the test, but the abnormality reappears soon, it can be confirmed that the noise is caused by problems such as piston knocking in the cylinder.

[0021] The basic principles and main features of the present invention and the advantages of the present invention are shown and described above. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention; therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is limited by the attached claims rather than the above description. Therefore, it is intended to include all changes within the meaning and scope of the equivalent elements of the claims in the present invention, and any figure marks in the claims should not be regarded as limiting the claims involved.

[0022] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A testing device for engine piston noise, comprising a testing box (10), an accelerator pedal (20), and a noise detector (30), characterized in that: The detection box (10) is connected to the accelerator pedal (20) and the noise detector (30); the detection box (10) controls the operation of the accelerator pedal (20); and the noise detector (30) transmits detected data to the detection box (10); a display screen (103), a keypad (102), and an armband (101) are installed on the detection box (10); a main control module, a Bluetooth module, and a rechargeable battery are arranged in the detection box (10); The noise detector (30) is provided with a plurality of them. The main body of the noise detector (30) is composed of a suction cup, a mounting box, and a handle. The suction cup is located at the bottom and is attached to the engine cylinder of the engine piston when in use. The top of the suction cup is provided with a mounting box. The top of the mounting box is provided with a handle mounted on it by screws. A vibration sensor (301) is mounted at the bottom center of the suction cup. The vibration sensor (301) detects vibration data when the suction cup is attached to the engine cylinder. A collection microphone (303) is installed on the top of the installation box. The collection microphone (303) is responsible for collecting sound wave signals emitted by the engine. A rotating shaft is installed on the bottom of the collection microphone (303). The direction of the collection microphone (303) can be adjusted by the rotating shaft. A cable connection port (304) is provided on one side of the top of the installation box. A data cable is plugged into the cable connection port (304). The other end of the data cable is connected to the detection box (10). The throttle pedal (20) is composed of a mounting frame (201) and a pedal rod (207); one end of the mounting frame (201) is arranged in an arc shape so that the mounting frame (201) can be easily abutted against a foot pedal of the cab; the other end of the mounting frame (201) is movably connected with a telescopic member (202); an end of the telescopic member (202) close to the mounting frame (201) is provided with a telescopic plate; screw holes are equidistantly provided on the top of the telescopic plate, and the screw holes are opened from top to bottom; a locking bolt (203) is screwed on the top of the connection between the mounting frame (201) and the telescopic member (202); the locking bolt (203) fixes the mounting frame (201) and the telescopic plate together downward; one end of the telescopic member (202) abuts under the driver's seat; An adjustment slot (204) is symmetrically provided on the upper left side of the mounting frame (201); a remote control motor (205) is mounted on the left side of the front side of the mounting frame (201) by means of bolts; a transmission end of the remote control motor (205) extends into the inner cavity of the mounting frame (201); and a driving gear (206) is mounted on the transmission end of the remote control motor (205); A pedal rod (207) is installed in the inner cavity of the mounting frame (201), and the pedal rod (207) is composed of a sleeve (2071), an adjustment rod (2074), a sliding rod (2076), and a gear plate (2077); the gear plate (2077) is installed at the bottom of the sliding rod (2076), and the gear plate (2077) is located directly above the driving gear (206); the bottom of the gear plate (2077) is provided with gear teeth, and the gear teeth are downwardly meshed with the driving gear (206); A limited rotation rod (2075) is provided at the bottom of the sleeve (2071), the limited rotation rod (2075) is plugged into the right side of the mounting frame (201), the rotation of the sleeve (2071) is maintained by the limited rotation rod (2075), an adjustment rod (2074) is sleeved on the limited rotation rod (2075), the left end of the adjustment rod (2074) is sleeved on the sliding rod (2076), and the two ends of the sliding rod (2076) are slidably inserted in the adjustment slot (204); A telescopic rod is arranged in the middle of the adjusting rod (2074), so that the adjusting rod (2074) can be telescopically matched when the sliding rod (2076) is displaced; the adjusting rod (2074) on one side is arranged in a triangle, and one end of the triangular adjusting rod (2074) is fixed on the sleeve (2071); a pedal (2073) is installed on the top of the sleeve (2071), and the pedal (2073) is synchronously tilted with the sleeve (2071) and abuts against the accelerator pedal of the car; A gear plate (2077) is fixed in the middle of the bottom of the adjusting rod (2074), and the driving gear (206) drives the gear plate (2077) and the sliding rod (2076) to move. When the sliding rod (2076) moves, it drives the adjusting rod (2074) to deform. After the adjusting rod (2074) drives the sleeve (2071) to tilt, the pedal (2073) abuts against the accelerator pedal of the car. The depth of stepping on the accelerator is controlled by adjusting the tilt size of the sleeve (2071). The accelerator pedal (20) is used to step on the accelerator pedal of the car to control the accelerator size, so as to cooperate with noise detection. A fixing bolt (2078) is provided in the middle of the sliding rod (2076). The fixing bolt (2078) penetrates the sliding rod (2076) and is screwed to the gear plate (2077) to facilitate the removal of the gear plate (2077).

2. The engine piston noise testing device according to claim 1, characterized in that: The armband (101) is symmetrically mounted on the bottom of the detection box (10), and the armband (101) is sleeved on the arm for use, and a Velcro strap is provided on the outside of the armband (101) for tightening the armband (101).

3. The engine piston noise testing device according to claim 1, characterized in that: The inner cavity of the sleeve (2071) is provided with a remote control telescopic motor (2072); a sleeve rod extending downward is provided at the bottom of the pedal (2073); the sleeve rod is inserted into the sleeve (2071); and a transmission end of the remote control telescopic motor (2072) is fixed upward to the bottom of the sleeve rod; the pedal (2073) is driven to telescope by the extension of the remote control telescopic motor (2072); the length of the pedal (2073) is changed by the telescopic movement, so as to facilitate adaptation to the height of different automobile accelerator pedals; and the telescopic range of the pedal (2073) does not exceed the length of the sleeve rod.

4. The engine piston noise testing device according to claim 1, characterized in that: A tilt sensor (2079) is embedded in the downward side of the outer wall of the sleeve (2071), and the tilt angle of the sleeve (2071) is detected to monitor the accelerator pedaling depth; a rechargeable battery and a Bluetooth module are also provided in the accelerator pedal (20), and the accelerator pedal (20) is connected to the Bluetooth module in the detection box (10) via the Bluetooth module, so as to transmit the tilt angle of the accelerator pedal (20) detected by the tilt sensor (2079).

5. The engine piston noise testing device according to claim 1, characterized in that: The detection box (10) establishes a connection with the noise detector (30) via a Bluetooth communication protocol; a rechargeable battery is also arranged in the installation box of the noise detector (30); a charging port (302) is arranged on the other side of the top of the installation box, and electric energy is replenished in the rechargeable battery via the charging port (302); a signal acquisition module and a Bluetooth module are arranged in the noise detector (30); a Bluetooth module is also arranged in the inner cavity of the detection box (10); and the Bluetooth module in the detection box (10) is provided with a plurality of Bluetooth channels; the detection box (10) is interconnected with the Bluetooth modules of the plurality of noise detectors (30) via the Bluetooth channels, and detection information is transmitted.

6. The engine piston noise testing device according to claim 1, characterized in that: A single person can perform the test work by using the test device, and a plurality of noise detectors (30) are arranged along the working position of the piston on the main thrust side of the engine cylinder body, and the vibration signal and the sound wave signal of the piston when it is running are collected through vibration. Since a plurality of noise detectors (30) are provided, they can be distributed in sequence along the position of the piston, or a piston range can be selected separately for testing.

7. A testing method for an engine piston noise testing device according to any one of claims 1 to 6, characterized in that: S1, arrangement of noise detectors (30): multiple noise detectors (30) are arranged along the working position of the piston on the main thrust side of the engine cylinder body, and vibration signals and sound wave signals of the piston when it is running are collected through vibration. Since multiple noise detectors (30) are provided, they can be distributed in sequence along the position of the piston, or a single piston range can be selected for detection; The installation position of the noise detector (30) is selected to be in the middle position of the upper half of the main thrust side of the cylinder body of the engine, mainly collecting vibration signals; the middle position from the crankshaft pulley end to the flywheel end, which is generally 10-12 cm away from the cylinder body in the main thrust side direction, mainly collecting sound wave signals; S2, test steps: placing the accelerator pedal (20) on the accelerator pedal of the car, and then controlling the accelerator pedal (20) to keep the accelerator of the car constant; the detection box (10) controls the remote control motor (205) and the remote control telescopic motor (2072) to complete the specified action; the remote control motor (205) drives the driving gear (206) and the gear plate (2077) to move, so as to achieve the displacement and inclination of the pedal rod (207), so that the pedal (2073) can abut against the accelerator pedal of the car, and the depth of the accelerator is controlled by adjusting the inclination angle of the sleeve (2071), so as to achieve the control of the accelerator size; the accelerator pedal (200) is also equipped with a remote control telescopic motor (2072), and the length of the pedal (2073) can be adjusted as needed to adapt to the height of different accelerator pedals of the car; The detection box (10) establishes a Bluetooth communication connection with the accelerator pedal (20) via a Bluetooth module, and is responsible for receiving in real time the tilt angle data transmitted by the accelerator pedal (20); at the same time, the detection box (10) is also connected to the noise detector (30) via Bluetooth, and receives the vibration and sound wave signals collected by the noise detector (30); these data are further analyzed and processed by the microprocessor in the detection box (10) to determine whether there is piston noise in the engine; S3, Test principle: Use the minimum time interval of the engine crankshaft signal as the measurement unit to determine the moment when the peak value of the vibration signal exceeds the peak limit and the moment when the sound wave reaches the peak value; Calculate the difference of the piston interval time, if the difference does not exceed the preset time difference, then judge the time is within the preset time range; If the time is within the preset time range, it is determined that the engine has piston noise.

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