JP2000186611A - Combustion pressure data collector of and analyzer of diesel engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make any state easily diagnosable even in case of an operative diesel engine while simplifying an outer boundary around the engine. SOLUTION: Combustion pressure in a diesel engine 1 is detected by a pressure sensor 2, thereby sampling combustion pressure data at high speed so as to carry out several samplings per 0.1 deg. in the turning angle of a crankshaft 3 by an analog-to-digital converter 55. A top dead center in the crankshaft 3 is detected by a turning angle sensor whereby a top dead center signal is outputted. With the control of a central processing unit 51, the sampling data of the A-D converter 55 and the top dead center signal both are stored in a random-access memory 53. Time series data are formed as the combustion pressure data of one piece per angle 1 deg., and these data are recorded in a memory card C via a memory card interface 56. Then the time series data are read out of this memory card C by a personal computer 6. Subsequently, both combustion pressure and differential diagrams are represented on a display by the personal computer 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diesel engine combustion pressure data collecting apparatus and a diesel engine combustion pressure data analyzing apparatus suitable for assisting diagnosis and maintenance of a large diesel engine.

[0002]

2. Description of the Related Art Heretofore, in order to diagnose and maintain a large diesel engine mounted on a ship or the like, a combustion pressure diagram which graphs changes in combustion pressure in a combustion chamber of a diesel engine has been created. Conventionally, in order to create this combustion pressure diagram, a card draw method using an indicator is often used.However, in this card draw method, since the recording paper is manually moved in the time axis direction, the card draw method is different from the crank angle. There is a problem that the pressure value is incorrect and the reproducibility of the combustion pressure diagram is poor.

Japanese Patent Laid-Open Publication No. Sho 59-100834 discloses a technique for measuring the in-cylinder pressure (combustion pressure) of a diesel engine and analyzing it with a computer. Determine the number of revolutions of the crankshaft, determine the sampling cycle when A / D converting the combustion pressure,
A technique is disclosed in which the combustion pressure is A / D converted at the determined sampling period to obtain combustion pressure data. In this way, by converting the combustion pressure diagram into digital data and analyzing it with a computer or the like, the state of the diesel engine can be more detailed and accurate than when analyzing based on the combustion pressure diagram created by the card draw method. Can be grasped.

[0004]

However, in the case of a diesel engine that operates for a long time, such as a ship that is sailing in the ocean, it is necessary to periodically diagnose the state during the operation of the diesel engine. Installing a dedicated calculator is
It is difficult from the viewpoint of protecting the installation space and the computer itself.

Accordingly, an object of the present invention is to make it possible to easily diagnose the condition of a running diesel engine while simplifying the periphery of the diesel engine.

[0006]

According to a first aspect of the present invention, there is provided a combustion pressure data collecting apparatus for a diesel engine which detects the combustion pressure of a diesel engine and outputs a pressure signal. A pressure sensor, a rotation angle sensor that outputs a reference signal corresponding to a reference position of a rotation angle of a crankshaft of the diesel engine, a sampling unit that samples the pressure signal output by the pressure sensor at high speed, and the sampling unit. Storage means for storing the pressure signal sampled in the above step and a reference signal from the rotation angle sensor; and the signal stored in the storage means as time-series data based on the rotation angle of the crankshaft. And data processing means for recording the data on a recording medium or outputting the data to a communication means.

According to a third aspect of the present invention, there is provided a combustion pressure data analyzing apparatus for a diesel engine based on time series data recorded on the recording medium or time series data inputted through the communication means. A pressure diagram is created, the combustion pressure diagram is displayed on a display screen, and a differential waveform diagram obtained by differentiating the combustion pressure diagram by a rotation angle is displayed on the same screen as the combustion pressure diagram. It is characterized by.

According to the combustion pressure data collecting apparatus for a diesel engine, the combustion pressure data of the diesel engine is recorded on a recording medium such as a memory card as time-series data based on the rotation angle of a crankshaft. Or output to the communication means. Further, the combustion pressure data analysis device for a diesel engine according to claim 3 can be constituted by a personal computer or the like, and is based on the time-series data recorded on a recording medium or the time-series data input via communication means. A combustion pressure diagram is created, and the combustion pressure diagram and a differential waveform diagram of the combustion pressure diagram are displayed on the same screen such as a display.

Therefore, time-series data can be supplied to a personal computer or the like constituting a combustion pressure data analyzer by a memory card or a communication means. This personal computer or the like can be provided at a location different from the diesel engine. Can be used. Further, the ignition point in the diesel engine becomes clear from the differential waveform diagram displayed on the same screen as the combustion pressure diagram.

[0010]

Embodiments of the present invention will be described below. FIG. 1 is a block diagram of a diesel engine analysis system according to an embodiment of the present invention, which inspects a large diesel engine (diesel engine) 1 mounted on a ship or the like. A pressure sensor 2 is attached to the diesel engine 1, and a rotation angle sensor 4 is arranged near the crankshaft 3 of the diesel engine 1. The pressure sensor 2 outputs an analog voltage signal corresponding to the combustion pressure in the combustion chamber of the diesel engine 1. The rotation angle sensor 4 outputs a top dead center signal (reference signal) at the top dead center of the piston according to the rotation of the crankshaft 3. Is output. The analog voltage signal from the pressure sensor 2 and the top dead center signal from the rotation angle sensor 4 are input to the measuring device 5.

The measuring device 5 includes a CPU 51, a ROM 52,
RAM 53, bus 54, A / D converter 55, memory card interface (I / F) 56, and operator 5
7, a CPU 51, a ROM 52, a RAM 53
The bus 54 constitutes a microcomputer for controlling the entire measuring device 5. The A / D converter 55 samples the analog voltage signal output from the pressure sensor 2 at high speed and converts it into a digital voltage signal, and constitutes a sampling unit. The memory card interface 56 writes and reads data to and from the memory card C. Further, the operator 57 is operated when designating the start of the data collection process. Then, the CPU 51 sets the RO
By executing the data collection program stored in M52, collection (sampling) of combustion pressure data, generation of time series data of combustion pressure data, writing to the memory card C, and the like are performed as described later.

The A / D converter 55 performs sampling at such a high speed that the angular error of the rotation angle of the crankshaft 3 falls within 0.1 °. For example, sampling is performed at such a rate that sampling can be performed several times per 0.1 °. Each time the A / D conversion is completed by one sampling and the digital data is determined, an interrupt signal is output to the CPU 51, and the CPU 51 reads the combustion pressure data by an interrupt process based on the interrupt signal. Also, CPU
The reference numeral 51 performs an interrupt process based on the top dead center signal output from the rotation angle sensor 4 and stores the generation of the top dead center signal in the RAM 53 in association with the combustion pressure data.

In the RAM 53, for example, as shown in FIG. 2, a combustion pressure data storage area for storing combustion pressure data and an address data storage area for storing address data of the combustion pressure data storage area are set. The address of each storage area is designated by an independent write pointer. The initial value (address value) of each pointer is set at the head position of the corresponding storage area, and is updated to the next address each time writing is performed.

On the other hand, in the personal computer 6 as a combustion pressure data analysis device, a data analysis program is stored (installed) in a hard disk device (not shown), and the data analysis program of the hard disk device is developed in an internal RAM. Data analysis is controlled based on the RAM program. Further, the personal computer 6 has a built-in memory card interface for reading data from the memory card C, reads time-series data from the memory card C, expands the data in an internal RAM, and performs calculation based on the time-series data. And display a combustion pressure diagram.

Since the large diesel engine 1 has a relatively low rotational speed, the high-speed sampling by the A / D converter 55 as described above allows the combustion pressure data with a high resolution to the rotational angle of the crankshaft 3 to be obtained. Can be sampled. Therefore, diesel engine 1
Thus, there is no need to detect the rotation speed and reset the sampling frequency, and it is possible to obtain a combustion pressure diagram with sufficient accuracy from the sampled combustion pressure data and the top dead center signal.

FIGS. 5 to 7 are flowcharts of a data collection program executed by the CPU 51 of the measuring device 5.
The operation of the measuring device 5 will be described based on each flowchart. 5 is started when the power is turned on, and the interrupt processing I in FIG. 6 is output each time the A / D conversion is completed by the A / D converter 55 and the digital data is determined. Triggered by an interrupt signal,
Interrupt process II is started by the top dead center signal of the rotation angle sensor 4. In this embodiment, the interrupt process II has a higher priority than the interrupt process I.

In the main flow of FIG. 5, first, in step S1, initialization processing such as setting of a write pointer in a combustion pressure data storage area and an address data storage area is performed, and in step S2, a memory card interface 53 is executed.
The state of the memory card C is monitored from the state of (1). If the memory card C is inserted, the operation
8 is operated. When the operation element 58 is operated, the interruption of the interruption processing II is permitted in step S4,
In step S5, the input of the first top dead center signal is monitored. If the input, the interrupt of the interrupt processing I is permitted in step S6, and the process proceeds to step S7.

At step S7, it is monitored whether or not the number of occurrences of the top dead center signal has reached a predetermined number (three or more). During this time, interrupt processing I and interrupt processing II are performed. When the number of occurrences of the top dead center signal reaches a predetermined number, in step S8, interrupts of the interrupt processing I and the interrupt processing II are prohibited, and data processing described later is performed to generate time series data of combustion pressure data. Then, in step S9, the generated time-series data is written to the memory card C, and the process ends.

The interrupt processing I shown in FIG. 6 is executed when the A / D converter 51 performs sampling. In step S11, the combustion pressure data is read from the A / D converter 51, and the process proceeds to step S11.
In step 12, the read combustion pressure data is written to the address indicated by the write pointer in the combustion pressure data storage area of the RAM 53. In step S13, the address of the write pointer in the combustion pressure data storage area is updated, and the process returns to the original routine.

The interrupt processing II shown in FIG. 7 is executed when the top dead center signal is generated. In step S21, the current address data indicated by the write pointer in the combustion pressure data storage area is read, and in step S22, the read address data is read. Is written to the address indicated by the write pointer in the address data storage area of the RAM 53, and in step S23, the address of the write pointer in the address data storage area is updated, and the routine returns to the original routine.

By the above interrupt processing I and interrupt processing II, the combustion pressure data sampled in the combustion pressure data storage area is obtained as shown in FIG. As shown in FIG. 2B, the address data in the combustion pressure data storage area corresponding to the time when the top dead center signal is generated is obtained in the address data storage area. This allows
Time-series combustion pressure data can be associated with a time-series top dead center signal.

Next, the data processing in step S8 will be described. First, three consecutive address data (address data itself is not continuous) in the address data storage area are selected, and combustion corresponding to two revolutions of the crankshaft is determined from the combustion pressure data storage area based on the selected address data. Cut out pressure data. The cut-out combustion pressure data is, for example, several tens of sampling data per degree by sampling several times per 0.1 degree at the crankshaft angle. One combustion pressure data per 1 ° is obtained from the values and the like.

The number of sampling data per degree is 36 when the difference between adjacent address data stored in the address data storage area (for example, ji in FIG. 2B) is 36.
Since it corresponds to the number of sampling data in 0 ° (one rotation), it can be obtained as (ji) / 360. Then, the data of two rotations (corresponding to 720 °) consisting of one combustion pressure data per 1 ° obtained in this way is correlated with the angle data indicating the rotational position of the crankshaft to be time-series data.

The time-series data is written into the memory card C as described above.
For example, as shown in FIG. 3, the angle data is written to the memory card C in a format such that the combustion pressure data corresponding to the angle is written next to the angle data. Note that this format may be a format in which the head combustion pressure data is determined to be an angle of 0 ° and the combustion pressure data is written continuously in the order of the angle, or may be any format. And this memory card C
Is loaded into the personal computer 6, and the personal computer 6 reads the time-series data.

FIG. 8 is a flow chart of the analysis processing in the personal computer 6. The personal computer 6 first reads the time series data from the memory card C in step S31, and in step S32, converts the time series data between the combustion pressure data. Spline processing is performed for interpolation to generate combustion pressure diagram data. Next, in step S33, a process of differentiating the data of the combustion pressure diagram with the angle is performed to generate data of a differential waveform diagram, and in step S34, for example, as shown in FIG. Display the waveform diagram on the display. It is to be noted that, by displaying a combustion pressure diagram in a normal state predetermined for the diesel engine 1 at the same time as these figures, diagnosis can be easily performed.

In the above embodiment, the time-series data obtained by the measuring device 5 using the memory card C is supplied to the personal computer 6, but the measuring device 5 and the personal computer 6 are connected to each other, for example. RS-2
The connection may be made by a communication means such as 32C, and the time-series data obtained by the measuring device 5 may be supplied to the personal computer 6 via this communication means.

Further, not only a memory card but also another recording medium such as a floppy disk may be used.

Further, data of a combustion pressure diagram is transmitted from a marine vessel on a communication satellite or the like, for example, and a diesel engine is diagnosed at a predetermined center based on the data of the combustion pressure diagram. It may be.

[0029]

As described above, according to the apparatus for collecting combustion pressure data of a diesel engine according to claim 1 of the present invention and the apparatus for analyzing combustion pressure data of a diesel engine according to claim 3, The condition can be easily diagnosed even with a running diesel engine while keeping it simple.

[Brief description of the drawings]

FIG. 1 is a block diagram of a diesel engine analysis system according to an embodiment of the present invention.

FIG. 2 is a diagram showing sampled combustion pressure data and a combustion pressure data storage area, and address data and an address data storage area in the embodiment.

FIG. 3 is a diagram showing an example of a format of time-series data written to a memory card in the embodiment.

FIG. 4 is a diagram showing a display example of a combustion pressure diagram and a differential waveform diagram in the embodiment.

FIG. 5 is a flowchart of a main flow of a data collection process in the embodiment.

FIG. 6 is a flowchart of interrupt processing I according to the embodiment.

FIG. 7 is a flowchart of interrupt processing II according to the embodiment.

FIG. 8 is a flowchart of an analysis process according to the embodiment.

[Explanation of symbols]

 Reference Signs List 1 diesel engine 2 pressure sensor 3 crankshaft 4 rotation angle sensor 5 measuring device 6 personal computer 51 CPU 52 ROM 53 RAM 54 bus 55 A / D converter 56 memory card interface 57 operator C memory card

Claims (3)

[Claims] A pressure sensor that detects a combustion pressure of a diesel engine and outputs a pressure signal; a rotation angle sensor that outputs a reference signal corresponding to a reference position of a rotation angle of a crankshaft of the diesel engine; Sampling means for sampling the pressure signal output from the sensor at high speed; storage means for storing the pressure signal sampled by the sampling means and a reference signal from the rotation angle sensor; and a signal stored in the storage means. Data processing means for producing time-series data based on the rotation angle of the crankshaft, and recording the time-series data on a recording medium or outputting the time-series data to a communication means. apparatus. 2. The apparatus for collecting combustion pressure data for a diesel engine according to claim 1, wherein said recording medium is a memory card. 3. A combustion pressure diagram is created based on the time series data recorded on the recording medium according to claim 1 or the time series data input via the communication means, and the combustion pressure diagram is displayed. A combustion pressure data analysis device for a diesel engine, wherein a combustion pressure diagram is displayed on a screen, and a differential waveform diagram obtained by differentiating the combustion pressure diagram with respect to a rotation angle is displayed on the same screen as the combustion pressure diagram.