Noise diagnostic system

Abstract

To precisely identify an intake valve and an exhaust valve that generate noise.SOLUTION: A noise diagnostic system according to the invention is configured to: when noise is determined to be generated by a driven valve system of an internal combustion engine, determine, on the basis of information on a crank angle in a predetermined period, information on a valve lift timing of the internal combustion engine, amounts of change in opening / closing timings of a variable valve timing mechanism and a waveform of a recorded sound, whether or not at least one of opening / closing timings of an intake valve and an exhaust valve of each of air cylinders in the predetermined period is included within a predetermined timing range including timings of peaks of a waveform of the recorded sound: and, when the at least one of opening / closing timings of the intake valve and the exhaust valve of each of the air cylinders in the predetermined period is included within the predetermined timing range, diagnose that the noise is generated by an intake valve or exhaust valve of an air cylinder whose opening / closing timing is included in the predetermined timing range among the intake valves and exhaust valves of a plurality of air cylinders.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to an abnormal sound diagnosis system. [Background technology]

[0002] Conventionally, as this type of abnormal sound diagnosis system, one that diagnoses abnormal sounds generated in an internal combustion engine has been proposed (for example, see Patent Document 1). In this system, when an abnormal sound (knock sound) is detected by a knock sensor in a knock sound detection gate section, it is diagnosed that the abnormal sound is caused by narrowing of the valve clearance due to the adhesion of deposits, etc. The knock sound detection gate section is set so as to avoid a knocking section where knocking is possible. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-98236 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the abnormal sound diagnosis system described above, it is necessary to set the knocking period in advance before detecting the abnormal sound. Since knocking occurs due to various causes, it is difficult to set the knocking period appropriately in advance. Therefore, the abnormal sound diagnosis system described above cannot accurately identify the intake valve and exhaust valve that are generating the abnormal sound.

[0005] The abnormal noise diagnosis system of the present disclosure has a primary objective of accurately identifying the intake valve and exhaust valve that are producing the abnormal noise. [Means for solving the problem]

[0006] The abnormal sound diagnosis system of the present disclosure employs the following measures to achieve the above-mentioned main object.

[0007] The abnormal sound diagnosis system disclosed herein is an internal combustion engine abnormal sound diagnosis system that diagnoses abnormal sounds generated in an internal combustion engine with multiple cylinders, the abnormal sound diagnosis system having a variable valve timing mechanism that can change the opening and closing timing of at least one of the intake valve and the exhaust valve, and when it is determined that the abnormal sound is generated from a valve system including the intake valve and the exhaust valve, the system determines whether or not at least one of the opening and closing timings of the intake valve and the exhaust valve for each cylinder during a predetermined period of time falls within a predetermined timing range that includes the timing of a peak of the waveform of the recorded sound, based on crank angle information during the predetermined period of time, valve lift timing information of the internal combustion engine, an amount of change in the opening and closing timing by the variable valve timing mechanism, and a waveform of the recorded sound, and when at least one of the opening and closing timings of the intake valve and the exhaust valve for each cylinder during the predetermined period of time falls within the predetermined timing range, the system diagnoses that the abnormal sound is generated in the intake valve or the exhaust valve of the cylinder whose opening and closing timing falls within the predetermined timing range among the intake valves and the exhaust valves of the multiple cylinders. [Brief description of the drawings]

[0008] [Figure 1] 1 is a diagram showing the outline of the configuration of an abnormal sound diagnosis system 10. [Diagram 2] 6 is a flowchart showing an example of each process of an abnormal sound diagnosis application. [Diagram 3] FIG. 13 is an explanatory diagram showing how the valve lift amount etc. corresponds to the crank angle θcr. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Next, a mode (embodiment) for carrying out the present disclosure will be described. Fig. 1 is a configuration diagram showing an outline of the configuration of an abnormal sound diagnosis system 10 as an embodiment of the present disclosure. The abnormal sound diagnosis system 10 of the embodiment is a system for supporting abnormal sound diagnosis of a vehicle V to be diagnosed (hereinafter referred to as "vehicle"), and includes a mobile terminal (hereinafter referred to as "terminal") 20 capable of communicating with a server 40.

[0010] The vehicle V includes an engine 30 with multiple cylinders (eight cylinders in the embodiment) and an electronic control unit (hereinafter referred to as "ECU") 32. The engine 30 is configured as an internal combustion engine driven by a hydrocarbon fuel such as gasoline or diesel. The engine 30 includes a variable valve timing mechanism 30a on an intake camshaft, which is capable of continuously changing the intake valve opening / closing timing VT (opening timing and closing timing) while maintaining an operating angle (angle between the opening timing and closing timing). In the variable valve timing mechanism 30a, an angle of the intake camshaft corresponding to the intake valve opening / closing timing VT that allows the engine 30 to efficiently output power is set as a reference angle. The angle of the intake camshaft is advanced from the reference angle to set the engine 30 in an operating state that allows high torque to be output from the engine 30, or the angle of the intake camshaft is set to a predetermined angle on the retard side (for example, the most retarded angle) to set the engine 30 in an operating state suitable for stopping or starting. The engine 30 is controlled by the ECU 32. The ECU 32 includes a microcomputer having a CPU, a ROM, a RAM, a flash memory, an input / output port, and a communication port, though not shown. To the ECU 32, signals from various sensors required for controlling the operation of the engine 30, such as a crank angle θcr from a crank position sensor that detects the rotational position of a crankshaft of the engine 30 and a cam angle from a cam position sensor that detects the rotational position of an intake camshaft that opens and closes an intake valve, are input via an input port. From the ECU 32, various control signals for controlling the operation of the engine 30, such as a control signal to a throttle valve, a control signal to an injection valve, and a control signal to a variable valve timing mechanism 30a, are output via an output port. The ECU 32 calculates the rotation speed Ne of the engine 30 based on the crank angle θcr of the engine 30 from the crank position sensor.

[0011] The server 40 is configured as a well-known computer and has a CPU, ROM, RAM, auxiliary storage device (e.g., flash memory), main storage device (e.g., HDD, SSD), communication module, etc., and exchanges various information with the terminal 20 via a network such as the Internet.

[0012] The terminal 20 is used by an operator (user of the abnormal sound diagnosis system 10) at a vehicle dealership, a repair shop, or the like, when performing a reproduction test to reproduce an abnormal sound using the vehicle V in which the abnormal sound has occurred. The terminal 20 is, for example, a smartphone or a tablet terminal, and includes an SoC having a CPU and a GPU, a ROM, a RAM, an auxiliary storage device (flash memory), a display (display unit) 21, a speaker (sound output unit) 22, a camera 23, a microphone 24, a communication module 25, and the like. The display 21 is configured as a touch panel type display. The speaker 22 outputs sound. The camera 23 captures images of the surroundings. The microphone 24 collects surrounding sounds. The communication module 25 exchanges various information with an electronic control device of the vehicle V via short-range wireless communication, and exchanges various information with a server 40 via a network such as the Internet.

[0013] An abnormal sound diagnosis application (software, hereinafter referred to as "diagnostic app") is installed in the terminal 20. The terminal 20 includes an acquisition unit 26, a recording unit 27, and a processing unit 28. The acquisition unit 26, the recording unit 27, and the processing unit 28 are each configured by the abnormal sound diagnosis application (software) in cooperation with hardware such as an SoC, a ROM, a RAM, a display 21, a speaker 22, a camera 23, a microphone 24, and a communication module 25. The acquisition unit 26 acquires various information from the vehicle V and the server 40. The recording unit 27 records sounds as recorded sounds. The processing unit 28 performs various processes and controls the display 21.

[0014] Next, an abnormal sound diagnosis procedure using the abnormal sound diagnosis system 10 will be described. When an operator (user of the abnormal sound diagnosis system 10) at a vehicle dealer, repair shop, or the like receives a request from the owner of the vehicle V to identify the cause of the abnormal sound or to eliminate the abnormal sound, the operator places each wheel of the vehicle V on the rollers of a chassis dynamometer and operates them together with the rollers. The operator may operate the vehicle V in a parked state. The operator also starts up a diagnostic app on the terminal 20. FIG. 2 is a flowchart showing an example of each process of the diagnostic app.

[0015] In the diagnostic application, first, the sound of the engine room (the room in which the engine is housed) of the vehicle V is recorded, and information on the valve lift timing (valve lift curve) of the intake valve and the exhaust valve from the ECU 32 of the vehicle V, information on the crank angle signal (crank angle θcr) from the crank position sensor at the time of recording the sound, the amount of change ΔVT from the reference angle of the opening and closing timing VT of the intake valve by the variable valve timing mechanism 30a at the time of recording the sound, and the rotation speed Ne of the engine 30 at the time of recording the sound are acquired and recorded (S100). Recording of the sound of the engine room may be started automatically at a predetermined time tstr (e.g., several seconds) after the diagnostic application is started, or may be started after a recording request and a recording button are displayed on the display 21 and the recording button displayed on the display 21 is tapped by the operator. Recording of the sound of the engine room may be ended after a predetermined recording time trt has elapsed since the start of recording, or may be ended when a recording end button is displayed on the display 21 after the start of recording and the recording end button displayed on the display 21 is tapped by the operator.

[0016] Next, it is determined whether the abnormal sound is an abnormal sound of a valve system including an intake valve and an exhaust valve based on the recorded sound and the rotation speed Ne of the engine 30 (S110). This determination is made by determining that the abnormal sound is an abnormal sound of the valve system when the timing at which the amplitude of the waveform of the recorded sound becomes large occurs once every two revolutions of the engine 30. If the abnormal sound is not an abnormal sound of the valve system, the display 21 is caused to display that the abnormal sound is not caused by the opening or closing of the intake valve or exhaust valve (S200), and this routine is terminated.

[0017] If the abnormal noise in S110 is a valve system abnormal noise, it is determined whether the abnormal noise is occurring around the cylinder head (S120). For this determination, a first selection button for selecting that the abnormal noise is occurring around the cylinder head and a second selection button for selecting that the abnormal noise is occurring at a location other than around the cylinder head are displayed on the display 21, and when the first selection button is tapped by the operator, it is determined that the abnormal noise is occurring around the cylinder head. When the operator taps the second selection button and the abnormal noise is occurring at a location other than around the cylinder head, the display 21 is caused to display that the abnormal noise is not due to the opening or closing of the intake and exhaust valves (S200), and this routine is terminated.

[0018] When an abnormal noise is generated around the cylinder head in S120, it is determined whether the engine 30 is a V-type engine (S130). This determination is made by displaying a third selection button for selecting that the engine 30 is a V-type engine and a fourth selection button for selecting that the engine 30 is not a V-type engine on the display 21, and when the operator taps the third selection button, it is determined that the engine 30 is a V-type engine. This determination may be made by storing in advance as a database information on the types of various engines and whether they are V-type engines or not, acquiring the type of the engine 30 from the ECU 32 of the vehicle V, and determining whether the type of the engine acquired is a V-type engine based on the information stored in the database. When the engine 30 is not a V-type engine in S130, the processing from S150 onwards is executed. When the engine 30 is a V-type engine in S130, information on the bank from which the abnormal noise is generated is acquired (S140). Here, a listening request requesting to listen to the sounds of the left and right banks with a stethoscope, a sixth selection button for selecting that the abnormal sound is coming from the left bank, and a seventh selection button for selecting that the abnormal sound is coming from the right bank are displayed on the display 21. An operator who visually recognizes the listening request listens to the sounds of the left and right banks with a stethoscope and selects either the sixth or seventh selection button. When either the sixth or seventh selection button is selected in this manner, the diagnostic app obtains information that the abnormal sound is coming from the selected bank.

[0019] Next, for all cylinders when engine 30 is not a V-type engine, or for the cylinder of the bank where the abnormal noise is occurring when engine 30 is a V-type engine, information on the valve lift timing (valve lift curve) of the intake valve and exhaust valve during a diagnosis period (predetermined period) from 0° to 720° of crank angle θcr, a change amount ΔVT, and a crank angle signal from the crank position sensor are obtained from the information input in S100, with the top dead center of the compression stroke of a reference cylinder (cylinder No. 1 in this embodiment) being set to 0° of crank angle θcr (S150), and the valve lift curve of the intake valve is corrected from the reference angle to the retarded or advanced side using the change amount ΔVT (S160). Then, the corrected intake valve lift timing, exhaust valve lift timing, crank angle signal, and sound waveform are associated with each other by crank angle θcr (time) (S170), and it is determined whether or not at least one of the intake valve and exhaust valve opening / closing timing VT for each cylinder during the diagnosis period coincides with the timing of the peak (maximum value) of the sound waveform of the recorded sound (S180). When at least one of the intake valve and exhaust valve opening / closing timing VT for each cylinder during the diagnosis period is included within a predetermined timing range including the timing of the peak of the waveform of the recorded sound, S180 determines that at least one of the intake valve and exhaust valve opening / closing timing VT for each cylinder during the diagnosis period coincides with the timing of the peak of the sound waveform.

[0020] FIG. 3 is an explanatory diagram showing an example of how the corrected intake valve lift amount, exhaust valve lift amount, crank angle signal, and sound waveform are associated with each other by the crank angle θcr (time) in the case where abnormal noise is generated in the right bank (in this embodiment, the second cylinder (#2), the fourth cylinder (#4), the sixth cylinder (#6), and the eighth cylinder (#8)). In the sound waveform, it is considered that the abnormal noise occurs at the timing when the amplitude is at its peak. Therefore, it is considered that the abnormal noise occurs when the intake valve or exhaust valve of the cylinder that opens and closes at the timing when the amplitude is at its peak among the intake valves and exhaust valves of each cylinder is opened or closed. For example, in FIG. 3, the amplitude of the sound waveform is maximum when the crank angle θcr is 180°, and the exhaust valve of the sixth cylinder is closed within a predetermined range including this timing. Therefore, it is considered that the abnormal noise occurs due to the closing of the exhaust valve of the sixth cylinder. In this way, by checking whether at least one of the intake valve and exhaust valve opening / closing timings VT for each cylinder during the diagnosis period coincides with the timing of the peak of the sound waveform, it is possible to determine which cylinder's intake valve or exhaust valve is causing the abnormal noise to be caused by its opening or closing.

[0021] If at least one of the intake valve and exhaust valve opening / closing timings VT for each cylinder during the diagnosis period does not match the timing of the peak of the waveform of the recorded sound in S180, the display 21 displays that the abnormal sound is not caused by the opening or closing of the intake valve or exhaust valve (S200), and this routine ends. If at least one of the intake valve and exhaust valve opening / closing timings VT for each cylinder during the diagnosis period matches the timing of the peak of the waveform of the recorded sound, the display 21 displays that the abnormal sound is caused by the opening or closing of the intake valve or exhaust valve of the cylinder whose opening / closing timing VT matches the peak of the waveform of the recorded sound (S190), and this routine ends. This makes it possible to accurately identify the intake valve and exhaust valve that are generating the abnormal sound.

[0022] In the abnormal sound diagnosis system 10 of the embodiment described above, when it is determined that an abnormal sound is generated from a valve train including the intake valve and exhaust valve of the engine 30, it is determined whether or not at least one of the opening and closing timings VT of the intake valve and exhaust valve for each cylinder during the diagnosis period falls within a predetermined timing range including the timing of the peak of the waveform of the recorded sound, based on crank angle information during a diagnosis period (predetermined period), valve lift timing information of the engine 30, the amount of change ΔVT in the opening and closing timing VT by the variable valve timing mechanism 30a, and the waveform of the recorded sound.When at least one of the opening and closing timings VT of the intake valve and exhaust valve for each cylinder during the diagnosis period falls within the predetermined timing range, it is determined that an abnormal sound is generated in the intake valve or exhaust valve of a cylinder whose opening and closing timing VT falls within the predetermined timing range, among the intake valves and exhaust valves of a plurality of cylinders, thereby making it possible to accurately identify the intake valve and exhaust valve generating the abnormal sound.

[0023] In the above embodiment, the vehicle V is an engine vehicle. However, the type of the vehicle V may be, for example, a moving body such as a vehicle equipped with an engine, such as an engine vehicle or a hybrid vehicle, or a train, or a device equipped with an internal combustion engine that is stationary and does not move.

[0024] Note that the correspondence between the main elements of the embodiment and the main elements of the invention described in the Means for Solving the Problem column does not limit the elements of the invention described in the Means for Solving the Problem column, since the embodiment is an example for specifically explaining the form for implementing the invention described in the Means for Solving the Problem column. In other words, the interpretation of the invention described in the Means for Solving the Problem column should be made based on the description in that column, and the embodiment is merely a specific example of the invention described in the Means for Solving the Problem column.

[0025] The above describes embodiments for implementing the present disclosure, but the present disclosure is not limited to these embodiments, and it goes without saying that the present disclosure can be implemented in various forms without departing from the gist of the present disclosure. [Industrial Applicability]

[0026] The present disclosure can be used in the manufacturing industry of abnormal sound diagnosis systems, etc. [Explanation of symbols]

[0027] 10 Abnormal noise diagnosis system (diagnostic app), 20 Mobile terminal (terminal), 30 Engine.

Claims

[Claim 1] An abnormal noise diagnosis system for an internal combustion engine, which diagnoses abnormal noise generated in an internal combustion engine having a plurality of cylinders and having a variable valve timing mechanism capable of changing the opening and closing timing of at least one of an intake valve and an exhaust valve, comprising: When it is determined that the abnormal noise is generated from a valve system including the intake valve and the exhaust valve, based on crank angle information and valve lift timing information of the internal combustion engine during a predetermined period, the amount of change in the opening and closing timing by the variable valve timing mechanism, and the waveform of the recorded sound, it is determined whether or not at least one of the opening and closing timings of the intake valve and the exhaust valve for each cylinder during the predetermined period falls within a predetermined timing range that includes the timing of a peak of the waveform of the recorded sound; When at least one of the opening / closing timings of the intake valve and the exhaust valve for each cylinder falls within the predetermined timing range during the predetermined period, it is diagnosed that the abnormal noise is occurring in the intake valve or the exhaust valve of the cylinder whose opening / closing timing falls within the predetermined timing range among the intake valves and the exhaust valves of the plurality of cylinders. Abnormal noise diagnosis system.

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