JPH0810178B2 - Diesel engine diagnostic device for private power generation - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a diagnostic apparatus for a diesel engine for private power generation, which determines whether the engine is operating normally or abnormally based on the engine sound and displays it.

Conventional technology Hospitals, telephone stations, broadcasting stations, unmanned relay stations, etc. are generally equipped with private power generators for blackouts. Such an in-house power generator must be ready for operation at any time, so it is inspected regularly.Aside from obvious abnormalities such as inability to start the diesel engine for in-house power generation of the generator, for example, the intake air of the engine. It is difficult to detect an abnormality such as an abnormality in the valve end gap that does not immediately hinder the operation of the engine by daily inspection.

However, if the private power generator breaks down during operation during a power failure due to the above abnormalities, it does not make sense to have a private power generator. It is strongly desired to keep it.

Therefore, as disclosed in, for example, Japanese Patent Laid-Open No. 61-66140, there has been proposed a device for automatically diagnosing the engine state from the engine sound and displaying the diagnostic result.

DISCLOSURE OF THE INVENTION The present invention, in a device for automatically diagnosing the state of the engine from the engine sound, performs more accurate diagnosis as compared with the conventional diagnostic device so that abnormality of each part of the engine can be easily and accurately facilitated. Therefore, it is an object of the present invention to provide a device useful for diagnosing a diesel engine for an in-house power generation device.

Configuration of the Invention A diagnostic device for an automatic power generation diesel engine according to the present invention comprises: (a) at least one microphone for capturing engine sound; (b) filter means for selecting a predetermined frequency component from an output signal from the microphone; c) frequency component switching means for switching the frequency component according to the diagnosis item, (d) timing signal output means for outputting a timing signal according to the rotational position of the engine, (e) putting the engine into a load state according to the diagnosis item (F) Engine load state detecting means for setting; (g) Processing means for converting the output signal from the filter means into a direct current component by envelope detection and converting it into digital data; (h) A digital output signal from the processing means, the timing signal, and a signal from the engine load condition detection means, Based on the diagnosis item, an average level of sound pressure, a peak level, and a peak appearance timing of sound pressure are obtained, and an analysis means for analyzing normality / abnormality by comparing with a preset reference value, and i) The constitutional feature is that the display means for displaying the analysis result by the analysis means is provided.

Examples Hereinafter, the present invention will be described in more detail based on the examples shown in the drawings. Here, FIG. 1 is a block diagram of an engine diagnostic device according to an embodiment of the present invention, FIG. 2 is a schematic flowchart of the operation of the embodiment device shown in FIG. 1, and FIG. 3 is an abnormality diagnosis flowchart of the operation of the device. , FIG. 4 is an example of sound pressure level data in the case of normal and abnormal intake valve end clearance, and FIG. 5 is the sound pressure level in case of normal and misfire (reduced cylinder) operation. It is a data illustration figure. The present invention is not limited by the embodiment shown in the drawings.

The engine diagnostic device 1 shown in FIG. 1 is a device for diagnosing the diesel engine E of the private generator G.

The diesel engine E is, for example, a 4-cycle, 6-cylinder diesel engine.

The diesel engine E is, for example, a 4-cycle, 6-cylinder diesel engine.

Engine sound of diesel engine E is microphone 2
It is captured by and is input to the filter 4 via the amplifier 3.

The filter 4 is a combination of a voltage tuning type high-pass filter and a low-pass filter, and selectively outputs only a component in a predetermined frequency band. The frequency is selected by the frequency control signal given from the microcomputer system 10.

The output signal of the filter 4 is the envelope converter 5
Envelope detection is performed by, and the output of the envelope converter 5 is input to the high speed A / D converter 6.

The top dead center pulse detected from the diesel engine E is input to the high speed A / D converter 6 as a trigger signal for timing.

The output signal of the high-speed A / D converter 6 is the data memory 7
And is read by the personal computer 20.

The microcomputer system 10 reads the load signal from the FO rack and outputs a frequency control signal to the filter 4 to select the frequency component according to the diagnostic item. Also,
The angle pulse signal is read, the timing is determined, and the timing data is output to the personal computer 20.

Based on the sound pressure data obtained from the data memory 7 and the timing data obtained from the microcomputer system 10, the personal computer 20 determines the average level, peak level and peak appearance timing of the sound pressure for a predetermined period according to the diagnostic item. Ask. Also, a predetermined reference plane set in advance is stored, the reference plane is compared with the average level of the sound pressure, and normality / abnormality is analyzed for each predetermined item. Further, the analysis result is displayed on the CRT and recorded on the XY plotter.

When an abnormality is detected, the personal computer 20
The fact is displayed on the CRT and the microcomputer system 10 is notified. The microcomputer system 10 blinks the alarm lamp.

FIG. 2 is a flow chart showing the operation of the engine diagnostic device 1.

First, an initial condition is set for the engine speed and the load amount according to the target diagnostic item (S1). For example, regarding the diagnosis item of "intake valve end gap", the rotation speed is 1200 rpm, and the load is 0
If% is specified, enter those numbers.

When the initial condition is set, the personal computer 20 loads the normal data of the corresponding diagnostic item from the disc (S2).

On the other hand, the microcomputer system 10 reads the operating state data (S3) and checks whether or not the operating state satisfies the set initial conditions (S4).

If the operating condition of the diesel engine E does not match the initial condition, the CRT indicates that the operating condition needs to be adjusted (S5).

If the operating condition matches the initial conditions, the operating condition is OK on the CRT.
Is displayed (S6), the operator gives an instruction to start diagnosis (S7).

When the diagnosis start instruction is given, the microcomputer system 10
Determines a diagnostic item from the load amount and outputs a frequency control signal to select the frequency in the filter 4.

For example, in the case of no-load operation, it is determined that the diagnosis item is "intake valve end gap", and a frequency control signal is given to the filter 4 so as to select 3.5 kHz to 4.7 kHz as the frequency for these items.

According to the inventors of the present invention, the diagnostic item of "intake valve end gap" is the frequency band 3.5k in the no-load operation state.
This is due to the fact that a remarkable abnormality was found in Hz to 4.7 kHz.

The high-speed A / D converter 6 converts the sound pressure data at a timing based on the top dead center pulse and stores it in the data memory 7.

The personal computer 20 appropriately reads the sound pressure data from the data memory 7 based on the timing data given from the microcomputer system 10 (S8).

When the data sampling process (S8) ends, abnormality diagnosis is performed (S9).

The result of abnormality diagnosis is displayed on the CRT, XY plotter, and alarm lamp, and is stored in the disc (S1
0).

Now, the abnormality diagnosis is performed in the procedure as shown in FIG.

First, the load amount is checked (S11), and if there is no load, an abnormality diagnosis of the intake valve end gap is performed (S12).

The abnormality diagnosis of the intake valve end gap is performed by the peak value of the sound pressure level and the appearance timing thereof. This is because the peak level of the sound pressure is increased due to the increase in the clearance between the valve guide and the valve stem, and the timing of the valve operation is delayed because the operation of the valve is delayed.

For example, as shown in FIG. 4, when the intake valve end gap is normal, the sound pressure level changes with a solid line, and when it is abnormal, the sound pressure level changes with a broken line, so a peak level of 0.7 V or higher is detected. At the same time, when the appearance timing is near the opening timing of the intake valve of the No. 4 cylinder, it can be diagnosed that the intake valve end clearance of the No. 4 cylinder is abnormal.

When the intake valve end gap abnormality is diagnosed for the No. 1 to No. 6 cylinders (S13), the abnormality diagnosis ends.

After finishing the diagnosis in the no-load operation, the operator sets the initial condition designated for the diagnosis item of "misfire (reduced cylinder) operation" (S1). For example, the rotation speed 1200 rpm,
Enter 50% load.

Thereby, the personal computer 20 loads normal data for the corresponding item (S2).

On the other hand, the microcomputer system 10 reads the operating state data (S3) and checks whether or not the operating state satisfies the set initial conditions (S4).

If the operating condition of the diesel engine E does not match the initial condition, the CRT indicates that the operating condition needs to be adjusted (S5).

The operator adjusts the diesel engine E so that the operating state is displayed on the CRT.

If the operating condition matches the initial conditions, the operating condition is OK on the CRT.
Is displayed (S6), the operator gives an instruction to start diagnosis (S7).

When the diagnosis start instruction is given, the microcomputer system 10
Determines a diagnostic item from the load amount and outputs a frequency control signal to select the frequency in the filter 4.

For example, in the case of 1/2 load operation, it is determined that the diagnostic item is "misfire (reduced cylinder) operation", and a frequency control signal is given to the filter 4 so as to select 550 Hz to 910 Hz as the frequency for these items. .

This is "misfire (reduced cylinder) operation" by the inventor of the present invention.
As for the diagnostic item, the fact that an abnormality is prominently found in the frequency band of 550 Hz to 910 Hz under the 1/2 load operation condition is found.

The personal computer 20 performs data sampling (S8) and performs abnormality diagnosis (S9).

As shown in FIG. 3, in the abnormality diagnosis processing, it is checked that the operation is not a no-load operation but a half-load operation (S11), and first, it is diagnosed whether or not the misfire (reduced cylinder) operation is performed ( S1
7).

In the malfunction diagnosis of the misfire (reduced cylinder) operation, it is detected that the sound pressure level is lowered at a timing near the fuel injection timing. This is because the sound pressure level is lowered because the combustion noise disappears due to the misfire.

For example, in FIG. 5, since the sound pressure level decreases near the fuel injection timing of the No. 4 cylinder, it can be determined that there is a misfire of the No. 4 cylinder.

When the misfire (reduced cylinder) operation from No. 1 cylinder to No. 6 cylinder is diagnosed (S18), the abnormality diagnosis process is terminated.

The abnormality diagnosis of each item may be performed, for example, for several tens of engine cycles, and the abnormality may be displayed only when 80% or more of the abnormality is diagnosed.

As can be understood from the above description, according to the engine diagnostic device 1, the diesel engine E for the private power generator is provided.
It is possible to automatically and easily determine whether the engine state is normal or abnormal.

As another example, in the diagnosis of the "intake valve end gap", the normal / abnormal state is determined depending on whether or not the peak value of the sound pressure level appears near the intake valve closing timing in the frequency band 2.1 KHz to 3.0 KHz. There are things to judge.

Further, in the diagnosis of "misfire (reduced cylinder) operation", there is one that selects a frequency band of 400 Hz to 550 Hz. Also,
As for this item, there is one that diagnoses in no-load operation.

Furthermore, as another embodiment, in the state of no load operation,
Examples include those that perform abnormality diagnosis with the diagnostic items of "exhaust valve end gap" and "radiator fan belt loosening".

For example, the abnormality diagnosis of the “exhaust valve end gap” is performed by the presence or absence of the peak value of the sound pressure level near the timing of opening the exhaust valve. This is because the peak level of the sound pressure increases due to the increase in the clearance between the valve guide and the valve stem, and the timing of the operation changes because the valve operation is delayed. On the other hand, in the frequency band 2.1 KHz to 3.0 KHz, there is also one that performs abnormality diagnosis of the "exhaust valve end gap" depending on whether or not the peak value of the high pressure level appears near the closing timing of the exhaust valve.

Further, for example, in the abnormality diagnosis of "radiator fan belt slackness", the average level of sound pressure rises, so the sound pressure level is integrated for one engine cycle, and it depends on whether or not the value is higher than a certain level compared to the normal case. to decide. This is because the radiator fan belt slips or taps due to the loose tension, and the noise level increases as a whole. On the other hand, it is also possible to take an integrated value of the sound pressure level for the frequency band 1.3 KHz to 2.0 KHz, 2.1 KHz to 3.0 KHz and compare it with the normal value to judge normality / abnormality. For this item, 1 /
There is also one that diagnoses by two-load operation.

Further, as another example, in the state of 1/2 load operation,
An example is one in which abnormality diagnosis is performed using the "injection timing" and "injection pressure" diagnostic items.

For example, the abnormality diagnosis of the "injection timing" is judged by the peak value of the sound pressure level and the appearance timing thereof. This is because the combustion timing changes due to the delay of the injection timing,
Also, the sound pressure level changes due to this.
On the other hand, there is also one that diagnoses "abnormal injection timing" from the sound pressure level in the frequency band 400 Hz to 550 Hz.

Further, for example, the abnormality diagnosis of the "injection pressure" is determined by comparing the average levels of the sound pressure levels for a predetermined period. this is,
This is because an abnormal noise such as a knocking noise is slightly generated after the combustion timing due to the pressure decrease. On the other hand, it is also possible to select a frequency band of 400 Hz to 550 Hz, 1.3 KHz to 2.0 KHz to diagnose "injection pressure" for abnormality.

EFFECTS OF THE INVENTION According to the present invention, (a) at least one microphone for capturing engine sound, (b) filter means for selecting a predetermined frequency component from an output signal from the microphone, (c) according to a diagnostic item Frequency component switching means for switching the frequency components, (d) timing signal output means for outputting a timing signal according to the rotational position of the engine, (e) engine load state setting means for setting the engine to a load state according to a diagnostic item (F) engine load state detecting means, (g) processing means for converting the output signal from the filter means and envelope detection into a direct current component, and converting this to digital data, (h) digital output from the processing means Based on the signal, the timing signal, and the signal from the engine load condition detecting means, and according to the diagnostic item. Analytical means for obtaining the average level, peak level and peak appearance timing of the sound pressure during the period and comparing it with a preset reference value for normality / abnormality, and (i) displaying the analysis result by the analytical means There is provided a diagnostic device for a diesel engine for in-house power generation, which is characterized by comprising a display means for selectively analyzing only predetermined frequency component data corresponding to the above diagnostic items and selectively extracting and analyzing the data. Therefore, it is not necessary to provide a plurality of filters in the frequency band corresponding to the diagnostic item, and the configuration can be simple. Furthermore, in the present invention, the engine is in a load state in which it is easy to detect an abnormality with respect to the diagnostic item. Since it is possible to make a diagnosis based on the digital data after setting to, it is possible to easily make a highly accurate diagnosis. Therefore, even a non-specialist can easily and accurately find an abnormality in each part of the engine.

In particular, abnormality diagnosis of a diesel engine for an in-house power generator is suitable.

[Brief description of drawings]

FIG. 1 is a block diagram of an engine diagnostic apparatus according to an embodiment of the present invention, FIG. 2 is a schematic flowchart of the operation of the embodiment apparatus shown in FIG. 1, and FIG. 3 is an abnormality diagnosis flowchart of the operation of the apparatus. FIG. 4 is an exemplary diagram of sound pressure level data in the case of normal and abnormal intake valve end clearance, and FIG. 5 is an exemplary diagram of sound pressure level data in the case of normal and misfire (reduced cylinder) operation. is there. Explanation of code 1 …… Engine diagnostic device 2 …… Microphone 4 …… Filter 10 …… Microcomputer system 20 …… Personal computer E …… Diesel engine for private power generator.

Claims (4)

[Claims] 1. (a) At least one for capturing engine sound
Microphones, (b) filter means for selecting a predetermined frequency component from the output signal from the microphone, (c) frequency component switching means for switching the frequency component according to the diagnostic item, (d) at the rotational position of the engine. Timing signal output means for outputting a corresponding timing signal, (e) engine load state setting means for setting the engine to a load state according to the diagnostic item, (f) engine load state detecting means, (g) from the filter means Processing means for converting the output signal and the DC component by envelope detection into digital data, and (h) based on the digital output signal from the processing means, the timing signal and the signal from the engine load condition detecting means, In addition, the average level of sound pressure, peak level, and peak appearance timing for a predetermined period are calculated according to the diagnostic items. Therefore, private power generation comprising an analyzing means for analyzing normality / abnormality by comparing with a predetermined reference value set in advance, and (i) a displaying means for displaying an analysis result by the analyzing means. Diesel engine diagnostic equipment for automobiles. 2. The frequency component switching means selects a frequency band of about 1 KHz to about 5 KHz for the diagnosis item of the intake valve end clearance, and selects a frequency band of about 400 Hz to about 2 KHz for the misfire (reduced cylinder). The diagnostic device for a diesel engine for private power generation according to claim 1. 3. A diagnostic apparatus for a diesel engine for private power generation according to claim 2, wherein the analyzing means analyzes the intake valve end clearance by the peak level of the sound pressure at the time of no load and the appearance timing thereof. 4. The analyzing means causes a misfire (reduced cylinder) depending on the average level of the sound pressure before and after the fuel injection timing at the time of 1/2 load.
The diagnostic apparatus for a diesel engine for private power generation according to any one of claims 2 and 3.