KR100749667B1 - System and method for engine condition diagnosis from crankshaft angular speed - Google Patents

Abstract

A system for diagnosing engine condition using a crankshaft speed and a method thereof are provided to increase reliability of an engine state diagnosis by constructing a preventive maintenance system to take a required action rapidly. A system for diagnosing engine condition using a crankshaft speed includes speed detecting sensors(2), a speed data collecting unit(3), a network interface(4), and a data storage and diagnosis terminal(5). The speed detecting sensors are installed at one side of a fly wheel which is connected to a crankshaft of an engine and detect a rotation speed of a crankshaft of each cylinder. The speed data collecting unit collects and filters the crankshaft rotation speed of each cylinder. The network interface transfers the rotation speed data to the data storage and diagnosis terminal through a wire or wireless network. The data storage and diagnosis terminal receives and stores speed data of the engine in a storage device, diagnoses the engine condition by an engine condition diagnosis program, and displays the result on a monitor(51).

Description

System and method for engine condition diagnosis from crankshaft angular speed}

1 is a block diagram of a system of the present invention.

2 is a conceptual diagram of sensor installation and signal detection according to the present invention system.

3 is a conceptual diagram illustrating periodic measurement showing the form of instantaneous crankshaft speed from the sensor signal used in the present invention.

Figure 4 is a waveform diagram showing the change state of the time series speed signal during normal operation of the engine and when a specific cylinder abnormality occurs.

Figure 5 is a waveform diagram showing a change in the frequency sequence speed signal during normal operation of the engine and when a specific cylinder abnormality occurs.

Figure 6 is a level monitoring conceptual diagram for determining the degree of engine abnormality progress using the fast Fourier transform value of the crankshaft speed change waveform in the system of the present invention.

Figure 7 is a waveform diagram showing the form of confirming the abnormality cylinder using the two input signals used in the present invention.

8 is a flowchart for explaining the method of the present invention.

Explanation of symbols on the main parts of the drawings

1: reciprocating engine

2: speed detection sensor

3: speed data collector

4: network interface unit

5: Terminal for data storage and analysis

11: fly wheel

51: monitor

The present invention relates to an engine condition diagnosis system and method using a crankshaft speed change for monitoring and diagnosing an online condition of an engine including one or more cylinders. More particularly, the present invention relates to an instantaneous speed change of an engine shaft. To diagnose the condition of each cylinder of the engine, and to establish a Preventive Maintenance system that recognizes that the abnormality of a specific cylinder has not advanced to the point of failure and takes necessary actions quickly. Invented.

In general, the state diagnosis of reciprocating machinery such as an engine is judged by integrating signals from various sensors (pressure, temperature, fuel consumption and speed) installed in the engine.

At this time, the method using the pressure (MIP: Mean Indicated Pressure) data, by installing a pressure sensor in each cylinder to measure the pressure (Pcomp) at the compression stroke and the pressure (Pmax) at the explosion stroke effective pressure (Pmep) in the cylinder It is a system that calculates the pressure automatically, and it is a system that usually requires the operator to measure several cylinders sequentially by hand.

The engine condition diagnosis method using the pressure data is the most reliable method by directly using the internal pressure of the cylinder, but it is not suitable for the online monitoring method because the detection system using the expensive pressure sensor is relatively expensive to bring each cylinder online. not.

In addition, the method using the intake / exhaust pressure and the intake / exhaust temperature can be online, but the reaction rate is slow, and it is difficult to accurately identify the problem occurrence site (cylinder).

On the other hand, the method using the vibration amount is most commonly used for diagnosing the condition of the mechanical equipment. Although the knowledge database is the most accumulated method, the vibration of the crankshaft is used because large bearings use journal bearings to support the crankshaft. As the components pass through the oil film supporting the journal bearings, critical data is lost, which limits their use.

In addition, the lubricating oil analysis technique can accurately obtain the wear information of a specific part of the engine, but since the oil is used for a long time according to the operation of the reciprocating device, the light transmittance is deteriorated, and most of the online lubricating oil analysis sensors use the light transmitting property. As a system for measuring the quantity, size, and composition of particles in the hydraulic fluid, the online analysis is limited.

That is, although the conventional methods are usefully used at present, the installation and maintenance cost of the sensor is high, and an abnormality can be detected only after the condition of the equipment deteriorates to some extent, and the response speed to the abnormal occurrence is slow. to be.

In addition, in terms of cost, it is difficult to detect an abnormal phenomenon that does not have continuity or a gradual abnormal condition that occurs instantaneously due to the presence of a state value that is difficult to monitor online.

Therefore, recently, in order to solve this problem, a research on a method of diagnosing the occurrence of misfire of the engine by monitoring the instantaneous rotational speed change of the engine has been conducted and is used as an effective method. Although it may be usefully used to determine the case of misfire, etc., there is a problem such as poor effectiveness to be applied by techniques such as predictive maintenance.

The present invention has been made to solve such a conventional problem, by using the crankshaft speed change of the engine to detect the instantaneous speed change of the engine shaft to diagnose the state of each engine cylinder, and as a result It is possible to build a predictive maintenance system that can take necessary measures in a timely manner without causing an abnormality in a particular cylinder to cause a failure, thereby greatly increasing the reliability of the engine diagnosis. An object of the present invention is to provide an engine condition diagnosis system using the crankshaft speed change and a method thereof.

The present invention for achieving the above object, the rotational speed as a pulse signal of a frequency that is installed on one side of the flywheel connected to the crankshaft of the reciprocating engine having several cylinders corresponding to the change in the angular velocity of the crankshaft corresponding to each cylinder Speed detection sensors for detecting the; A speed data collector for receiving, collecting and filtering the rotational speeds of the crankshafts of the cylinders detected and output in real time by the speed detection sensors; A network interface unit for transmitting the rotational speed data for each cylinder collected by the speed data collecting unit to a data storage and analysis terminal through a wired or wireless network; It receives the speed detection data of the reciprocating engine through the network interface unit and stores it in its own memory and analyzes it in real time through the engine condition analysis program and displays the result on the monitor and notifies the system operator with an alarm. Characterized in that configured as a terminal for data storage and analysis.

The speed data collection unit may further include a function of collecting data and driving a diagnostic algorithm to actively transmit data to a terminal for data storage and analysis at the time when an abnormal occurrence is inferred.

On the other hand, the present invention for achieving the above object, the speed by the pulse signal of the frequency corresponding to the change in the angular speed of the crankshaft in each cylinder through the speed detection sensors installed on one side of the flywheel connected to the crankshaft of the reciprocating engine Detecting; Collecting and filtering the detected speed detection signal and transmitting the data to a terminal for data storage and analysis; The data storage and analysis terminal analyzes the change of the crankshaft angular velocity in the time axis and the frequency domain to diagnose an engine abnormality, and the speed of each section is detected by detecting the instantaneous speed signal (pulse) of the crankshaft about the time axis. After calculating the fast Fourier transform to determine the state of the rotating shaft system to perform the alarm through the corresponding safety measures or alarms; characterized in that consisting of.

At this time, the step of diagnosing an abnormal occurrence of the reciprocating engine in the data storage and analysis terminal, 1X (RPS: Revolution Per Second) or 2X frequency components (in case of two strokes and four strokes, the monitored frequency is different) Managing the size of each of the levels; When the level of 1X or 2X frequency component is divided into normal state, caution state, monitoring state, warning state and fault state, the alarm notification and safe operation are executed when the specific level is reached. If it is determined that the alarm is notified, and if the status of a particular cylinder is determined as a warning state or a failure state, taking the safety measures by deceleration, and informs through an alarm characterized in that the step of re-confirming the state of the cylinder .

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 1 shows the configuration of the system of the present invention, Figure 2 shows a sensor installation and signal detection conceptual diagram according to the system of the present invention.

According to the present invention, the system is installed on one side of the flywheel 11 connected to the crankshaft of the reciprocating engine 1 having several cylinders, and rotates with a pulse signal of a frequency corresponding to the change in the angular velocity of the crankshaft corresponding to each cylinder. Speed detection sensors 2 for detecting a speed;

A speed data collector (3) for receiving, collecting and filtering the rotational speeds of the crank shafts of the cylinders detected and output in real time by the speed detection sensors (2);

A network interface unit 4 for transmitting the rotational speed data for each cylinder collected by the speed data collecting unit 3 to a data storage and analysis terminal 5 through a wired or wireless network;

The speed detection data of the reciprocating engine 1 is received through the network interface unit 4 and stored in the internal memory, and the engine state analysis program analyzes the data in real time and displays the result on the monitor 51. Of course, the data storage and analysis terminal for notifying the system operator, such as an alarm (5) is characterized in that the configuration.

In addition, the speed data collection unit 3 further includes a function of collecting data and driving a diagnostic algorithm to actively transmit data to the data storage and analysis terminal 5 at the time when an abnormal occurrence is inferred.

2 is a conceptual diagram of sensor installation and signal detection according to the present invention system, FIG. 3 is a conceptual diagram illustrating a periodic measurement showing the instantaneous crankshaft speed from the sensor signal used in the present invention, and FIG. 4 is an engine. Shows a waveform diagram showing the change state of the time series speed signal at the time of normal operation and the occurrence of a specific cylinder abnormality, and FIG. 5 shows the waveform diagram showing the change state of the frequency sequence speed signal at the time of normal operation of the engine and a specific cylinder abnormality.

6 is a conceptual diagram illustrating a level monitoring process for determining an engine abnormality progress rate using a fast Fourier transform value of a crankshaft speed change waveform in the system of the present invention, and FIG. 7 shows two input signals used in the present invention. The waveform diagram which showed the form which confirms the abnormality cylinder is shown, and FIG. 8 shows the flowchart for demonstrating the method of this invention.

According to the present invention, according to the present invention, the speed detection sensor (2) installed on one side of the flywheel (11) connected to the crankshaft of the reciprocating engine (1) as a pulse signal of the frequency corresponding to the change in the angular speed of each cylinder crankshaft Detecting a speed (S1);

 Collecting and filtering the detected speed detection signal through the speed data collector (3) and transmitting the data to the terminal (5) for data storage and analysis (S2);

The data storage and analysis terminal 5 analyzes the change of the crankshaft angular velocity in the time axis and the frequency domain to diagnose the abnormality of the engine 1, and detects the instantaneous speed by detecting the crankshaft speed for the time axis. After calculating the speed change data to the high speed Fourier transform to determine the state of the engine rotation system and to give an alarm through the corresponding safety measures or alarm (S3); characterized in that it consists of.

At this time, the step (S3) of diagnosing an abnormal occurrence of the reciprocating engine (1) in the data storage and analysis terminal (5) includes: dividing and managing the magnitudes of the 1X or 2X frequency components for each level;

When the size of 1X or 2X frequency component is divided into normal state, caution state, monitoring state, warning state and fault state, the alarm notification and safe operation are executed when the specific level is reached. If it is determined that the attention state or monitoring state through an alarm, and if the state of a particular cylinder is a warning state or a failure state, taking safety measures through deceleration, and informs through an alarm and then re-check the state of the cylinder; Characterized in that consisting of.

Referring to the effect of the present invention and the system configured as described above are as follows.

First, the system in which the apparatus of the present invention is mounted is largely a data storage and analysis terminal 5 having a speed detecting sensor 2, a speed data collecting unit 3, a network interface unit 4, and a monitor 51. The configuration is the main technical component.

In this case, the speed detection sensor (2) is installed on one side of the flywheel (11) connected to the crank shaft of the cylinder in the reciprocating engine (1) having several cylinders, respectively, when driving the reciprocating engine (1) The rotational speed is detected as a pulse signal of a frequency corresponding to the change in the angular velocity of the crankshaft corresponding to each cylinder.

In the above, the reciprocating engine 1 includes a reciprocating internal combustion engine such as a gasoline engine, a diesel engine and a gas engine, and the speed detecting sensor 2 is installed in a gear formed on an engine flywheel. It will include an encoder.

In addition, the speed data collector 3 receives and collects the rotational speed of the crankshaft of each cylinder which is detected and output in real time by the speed detection sensors 2 and is included in each speed detection signal. To filter the noise signal.

In this case, the engine speed pulse signal measured by the speed detection sensor 2 may include a processing error of the gear formed on the flywheel and a noise signal due to an error factor of digital sampling. In order to remove this, it is possible to extract an accurate velocity pulse by applying an appropriate filtering process. Software filtering and hardware filtering can be selectively applied as the filtering technique used here.

In addition, the network interface unit 4 has a function of transferring the rotational speed data for each cylinder collected by the speed data collection unit 3 to the data storage and analysis terminal 5 through a wired or wireless network. Will be performed.

Therefore, the data storage and analysis terminal 5 receives the speed detection data of the reciprocating engine 1 through the network interface unit 4 and stores it in its own storage device and at the same time through an engine condition analysis program. The result of the analysis is displayed on the monitor 51 as well as notified to the system operator through an alarm not shown.

At this time, the data storage and analysis terminal 5 extracts instantaneous angular velocity components by measuring intervals between pulses to obtain instantaneous angular velocity changes from the velocity pulse signal of each cylinder measured by the speed detection sensor 2. In addition to the above-described speed extraction method, the angular velocity may be extracted by applying an F / V converter.

On the other hand, the engine state diagnosis method by the above system, first, the angular speed change of each cylinder crankshaft through the speed detection sensor (2) installed on one side of the flywheel (11) connected to the crankshaft of the reciprocating engine (1) The speed is detected by the pulse signal of the corresponding frequency (S1).

Subsequently, the speed detection signal detected above is collected and filtered through the speed data collector 3, and then transmitted to the data storage and analysis terminal 5, so that the data storage and analysis terminal 5 has a crank shaft. The change in the angular velocity is analyzed in the time axis and the frequency domain to diagnose whether the engine 1 is abnormal.

That is, after the instantaneous speed is calculated by detecting the crankshaft speed with respect to the time axis in the data storage and analysis terminal 5, the speed change data is converted into a fast Fourier transform to determine the state of the engine shaft system and corresponding safety. The alarm is triggered through the action or alarm (S3).

In this case, as a method of diagnosing an abnormal occurrence of the reciprocating engine 1 in the data storage and analysis terminal 5, the magnitudes of the 1X or 2X frequency components are divided and managed for each level, followed by the magnitudes of the 1X or 2X frequency components. It divides into normal status, caution status, monitoring status, warning status and fault status, and when it reaches a certain level, it performs alarm notification and safe operation.

As such, when the magnitude of the 1X or 2X frequency component is compared with a specific level corresponding to the normal state, the attention state, the monitoring state, the warning state, and the failure state, and it is determined that the specific cylinder is in the attention state or the monitoring state, an alarm is notified. If the status of a particular cylinder is determined to be a warning or fault condition, safety measures by deceleration are taken, the alarm is notified, and the status of the cylinder is checked again.

That is, the present invention detects the crankshaft rotation pulse and the reference pulse (one pulse output at one rotation or two rotations) through the speed detection sensor 2 from the reciprocating engine 1, which is a diagnosis target, and the speed detection sensor 2 The data collected from the data is collected and filtered through the speed data collecting unit 3 and transmitted to the data storage and analysis terminal 5 through the network interface unit 4 so that the data storage and analysis terminal 5 pulses. The period of rotation is extracted to extract the instantaneous rotational speed, and the extracted velocity signal is fast Fourier transformed (FFT) to determine the degree of abnormality.

As described above, when an abnormality occurs in a specific cylinder as determined by the data storage and analysis terminal 5, a problem cylinder is found by combining the reference frequency, the rotational speed signal, and the explosion order for each cylinder.

On the other hand, Figure 3 shows the form of measuring the interval between the pulses to obtain the instantaneous angular velocity change from the pulse signal measured in the manner of Figure 2, using the signal filtered through the speed data collector 3 Instantaneous angular velocity components can be extracted.

4 shows the angular velocity change with respect to the time axis. The angular velocity change signal in the normal operation state shows a sinusoidal shape, but when an abnormality occurs in a specific cylinder, the angular velocity change waveform is changed.

The change in the angular velocity shown on the time axis of FIG. 4 is performed on the frequency axis by performing the fast Fourier transform, resulting in the form as shown in FIG. 5.

In this case, in the normal operation state, the frequency of 1x or 2x or RPS (revolution per second) of the engine multiplied by the number of cylinders is large.

This is because a perfectly sinusoidal waveform is achieved when the generated torque between the cylinders is constant due to the uniform in-cylinder combustion pressure.

However, when one or more valves fail, the combustion pressure balance between the cylinders is broken, and as a result, the frequency of the crankshaft 1X or 2X component is increased.

FIG. 6 illustrates a method for managing the frequency of the 1X or 2X component (in the drawing, which is an example of the 1X component) generated by the level according to the engine fault diagnosis technique targeted by the present invention.

When reaching a certain level by dividing into normal state, caution state, monitoring state, warning state and fault state, the operator generates an alarm sound through alarm and performs safe operation such as engine slow down. Damage to the entire engine due to abnormal cylinders can be reduced.

FIG. 7 illustrates a method of checking an abnormal cylinder when it is diagnosed that an abnormality has occurred. A period of a reference frequency signal received with an engine speed pulse is converted into a number of time slots equal to the number of engine cylinders. The faulty cylinder is found by linking the timeslot of the fault with the engine cylinder explosion sequence.

In this case, the abnormality of the time slot may be determined by comparing the relationship between the maximum angular velocity and the minimum angular velocity on the time series in addition to visual confirmation.

As described above, the present invention diagnoses the state of the engine equipment by using the change of the crankshaft angular velocity, and the condition diagnosis result is a CBM (Condition Based Maintenance) diagnosis technique that uses peripheral operation data such as pressure, temperature and speed of the engine equipment after alarm notification. By using it as a reference signal to find out the abnormal component, it is possible to diagnose the state of the engine in real time using the engine pulse signal of one cycle of the state of the engine which is out of the normal operation state.

Although the above-described embodiments have been described with respect to the most preferred embodiments of the present invention, it is not limited to the above embodiments, and it will be apparent to those skilled in the art that various modifications can be made without departing from the technical spirit of the present invention.

As described above, according to the present invention, the state of each cylinder is diagnosed by detecting the instantaneous speed change of the engine shaft by using the crankshaft speed change of the engine. It is a very useful invention that can significantly improve the reliability of engine condition diagnosis by establishing a predictive maintenance system that can take necessary actions in a timely manner without progressing to the extent that it causes an increase.

Claims (6)

delete Speed detection sensors installed at one side of the flywheel connected to the crank shaft of the reciprocating engine having several cylinders to detect the rotation speed with a pulse signal of a frequency corresponding to the change in the angular speed of the crank shaft corresponding to each cylinder; A speed data collector for receiving, collecting and filtering the rotational speeds of the crankshafts of the cylinders detected and output in real time by the speed detection sensors; A network interface unit for transmitting the rotational speed data for each cylinder collected by the speed data collecting unit to a data storage and analysis terminal through a wired or wireless network; It receives the speed detection data of the reciprocating engine through the network interface unit and stores it in its own memory and analyzes it in real time through the engine condition analysis program and displays the result on the monitor and notifies the system operator with an alarm. Data storage and analysis to the terminal; The speed data collector further includes a function of collecting data and driving a diagnostic algorithm to actively transmit data to a terminal for data storage and analysis at the time when abnormality is inferred. Engine Condition Diagnosis System. Detecting a speed with a pulse signal of a frequency corresponding to a change in the angular speed of the crankshaft in each cylinder through speed detecting sensors installed at one side of the flywheel connected to the crankshaft of the reciprocating engine; Collecting and filtering the detected speed detection signal and transmitting the collected data to the terminal for data storage and analysis; The crankshaft angular velocity change in the data storage and analysis terminal is divided into a steady state, a caution state, a monitoring state, a warning state, and a fault state in the time axis and the frequency domain to diagnose an engine abnormality, but to crank the time axis. Calculating the instantaneous speed by detecting the shaft speed, and converting the speed change data into a high-speed Fourier transform to determine the state of the engine's rotating shaft system and alarming through safety measures or alarm corresponding thereto. Engine condition diagnosis method using crankshaft speed change. The method according to claim 3, Diagnosing a cylinder for an abnormal occurrence of a reciprocating engine in the data storage and analysis terminal, Managing the magnitudes of the 1X or 2X frequency components by level; When the size of 1X or 2X frequency component is divided into normal state, caution state, monitoring state, warning state and fault state, the alarm notification and safe operation will be performed. If it is determined in the above state as an caution state or a monitoring state, it is notified through an alarm, and when the state of a particular cylinder is determined as a warning state or a fault state, it takes safety measures through deceleration and informs it via an alarm, and then checks the state of the cylinder again. Engine state diagnosis method using the crankshaft speed change, characterized in that consisting of steps. The method according to claim 4, The crankshaft speed change may be used as a reference signal for detecting an abnormal component by applying a CBM diagnosis technique using ambient operating data such as pressure, temperature, and speed of engine equipment after alarm notification. Engine condition diagnosis method used. The method according to claim 4, The abnormality occurrence cylinder is an engine state diagnosis method using a crankshaft speed change, characterized by finding the reference frequency at which one pulse per cycle of the engine's operation pulse signal is divided by a time slot equal to the number of cylinders of the engine.

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