JP5539747B2 - Abnormality and deterioration diagnosis method of main gas valve for gas engine - Google Patents

Description

  The present invention relates to an abnormality of a main gas valve for setting a fuel gas amount to be supplied to an air-fuel mixture supply passage for supplying an air-fuel mixture to the main chamber of a gas engine having a combustion chamber having a sub chamber communicated with an upper portion of the main chamber. And a method for diagnosing deterioration.

  A gas engine having a combustion chamber composed of a main chamber and a sub chamber communicating with the upper portion of the main chamber has been well known (for example, Patent Document 1). In the case of this type of gas engine, a gas supply pipe for supplying fuel gas is communicated with an air-fuel mixture supply path for supplying air-fuel mixture to the main chamber, and a main gas valve (main pressure regulating valve in Patent Document 1) is connected to the gas supply pipe. Is installed.

  The gas engine having the above-described configuration is used, for example, in power generation equipment that generates power by transmitting a driving force from an output shaft to a generator. In the case of this gas engine, based on the supply pressure (air amount) measured by a sensor installed in the mixture supply path, the amount of fuel gas to be mixed with the fuel gas mixed with the air flowing through the mixture supply path is set. The opening and closing of the main gas valve is controlled to set the supply amount.

  In checking the main gas valve, the operating state is diagnosed by either measuring the operating current during periodic maintenance or checking the operating sound when the engine is stopped.

  Among these, in the diagnosis for measuring the operating current of the main gas valve, if the measured current value is outside the appropriate range, it is determined that there is an abnormality and the main gas valve is replaced. On the other hand, in the diagnosis for confirming the operation sound of the main gas valve when the engine is stopped, if the operation sound is low, it is determined that there is an abnormality and the main gas valve is replaced.

  However, since periodic maintenance is performed once every several months, there is no method for detecting when the abnormality or deterioration of the main gas valve progresses during this period, which may result in poor combustion and engine shutdown. In addition, the gas engine used for the power generation equipment that confirms the operation sound of the main gas valve when the engine is stopped may not stop the engine for a long period of time.

  In order to confirm the state of the main gas valve, an open / close detector and a flow rate detector are effective. However, in the case of the gas engine, these cannot be installed because of its structure.

JP 2009-221937 A

  The problem to be solved by the present invention is that the conventional abnormality and deterioration diagnosis of the main gas valve for a gas engine is performed at the time of regular maintenance of the main gas valve or when the engine is stopped. The point is that it is not predicted to deteriorate.

An abnormality and deterioration diagnosis method for a main gas valve for a gas engine of the present invention includes:
To enable daily prediction of abnormalities and deterioration of the main gas valve,
A method for diagnosing the state of a main gas valve installed in the middle of a gas supply pipe for a main combustion chamber for supplying fuel gas to an air-fuel mixture supply passage communicating with each cylinder chamber of a gas engine,
A stable combustion state for each cylinder based on the exhaust gas temperature detected by the exhaust gas temperature sensor provided in the exhaust gas exhaust passage of each cylinder of the gas engine and the knocking value detected by the knock sensor provided in each cylinder of the gas engine Collecting the injection offset value, which is a value that adjusts the fuel gas injection time set to keep
The average injection offset value calculating means for calculating the injection offset value for each cylinder as the average injection offset value extracted during the day,
Judgment means for monitoring the fluctuation of the daily average injection offset value calculated by the average injection offset value calculation means and judging whether or not the main gas valve is abnormal,
With
When the average injection offset value calculated by the average injection offset value calculating means starts to decrease or increase and deviates from a predetermined reference range, it is determined that the state of the main gas valve shows a sign of abnormality. The most important feature.

  In the present invention, since it is determined whether or not the state of the main gas valve shows a sign of abnormality based on the daily average injection offset value, a sign of abnormality of the main gas valve is routinely displayed even in a remote place away from the site. Since it can be determined, it becomes possible to prevent troubles.

It is the figure which showed schematic structure of the gas engine which applies the abnormality and deterioration diagnostic method of the main gas valve for gas engines of this invention. It is a figure explaining an example of combustion control of each cylinder, (a) is a case where the combustion state of some cylinders enters a knocking region or misfire region, and (b) is a knocking region or misfire of all cylinders. It is the figure which showed the case where it does not enter into an area. It is the figure which showed an example of the injection offset value collected in the remote monitoring room. It is the figure which showed an example of the analysis example of an injection offset value.

  In the present invention, the average injection offset value obtained by calculating the injection offset value for each cylinder extracted during the day, with the object of making it possible to predict abnormality or deterioration of the main gas valve on a daily basis. It was realized by judging by the change of a certain period.

Hereinafter, the present invention will be described in detail with reference to FIGS.
FIG. 1 is a diagram showing a schematic configuration of a gas engine to which a method for diagnosing abnormality and deterioration of a main gas valve for a gas engine of the present invention is applied.

  The gas engine that is the subject of the present invention is composed of a cylinder head 1, a cylinder block 2, and the like. Among these, the cylinder block 2 is formed with a plurality of (for example, four) cylinder bores 2a, and a piston 3 is slidably accommodated in each cylinder bore 2a. Although not shown in the figure, an intake valve and an exhaust valve are attached to the cylinder head 1 so as to be openable and closable.

  The combustion chamber 4 of the engine communicates with the main combustion chamber 4a formed on the lower surface side of the cylinder head 1 above the upper end surface of the piston 3 accommodated in the piston bore 2a. And a pre-combustion chamber 4b formed in the cylinder head 1.

  The fuel gas supplied to the pre-combustion chamber 4b via the pre-combustion chamber gas supply pipe 6 is ignited by the spark plug 5 disposed in the pre-combustion chamber 4b and burned in the pre-combustion chamber 4b. A flame is injected into the chamber 4a. In the main combustion chamber 4a, the mixture of the fuel gas supplied from the main combustion chamber gas supply pipe 7 to the mixture supply path 8 and the air sent through the mixture supply path 8 is ignited by the injected flame. And burn.

  Due to this combustion, the piston 3 is reciprocated, the reciprocating motion is converted into rotational motion by the crank mechanism 21, and the output shaft 22 is rotated to generate output for power generation. The exhaust gas after combustion is discharged from the exhaust valve through the exhaust gas discharge path 9.

  The operation of opening and closing the supply valve and the exhaust valve when supplying air to the combustion chamber 4 and exhausting from the combustion chamber 4 is performed by transmitting power from the output shaft 22 to a camshaft or the like. Done.

  In the case of the gas engine having the above configuration, the exhaust gas exhaust passage 9 is provided with an exhaust gas temperature sensor 10 for detecting the temperature of the exhaust gas, and the output shaft 22 is provided with a generator 23. A main gas valve 11 is provided in the middle of the main combustion chamber gas supply pipe 7 to adjust the amount of fuel gas supplied to the mixture supply path 8. The pre-combustion chamber gas supply pipe 6 has a pre-combustion chamber gas control valve 12 that adjusts the amount of fuel gas supplied to the pre-combustion chamber 4b, and a check valve 13 that prevents the backflow of combustion gas. Each is provided at the tip. Further, a knocking sensor 14 for measuring a knocking value (quantitative representation of the current combustion state) is provided on the upper surface of the cylinder head 1.

  In the combustion control of the engine, the opening time (reference injection period) of the main gas valve 11 commanded to the plurality of cylinders is set to a value corresponding to the output (generated power) of the generator 23. All are automatically controlled at once.

Simultaneously with this automatic control, in order to keep the knocking value and exhaust gas temperature for each cylinder constant , the injection offset value, which is a value for adjusting the fuel gas injection time to the main gas valve 11 , is automatically controlled for each cylinder.

  As for the combustion state of each cylinder, the ignition timing, temperature offset, and injection offset value are adjusted (increased or decreased), and as shown in FIG. 2B, the combustion state of each cylinder enters the knocking region or misfiring region. It is controlled two-dimensionally so that there is no. FIG. 2A is a diagram showing a case where the combustion state of some cylinders enters a knocking region or a misfire region.

  The output (generated power) acting on the engine output system, the knocking value measured by the knocking sensor 14, and the exhaust gas temperature value measured by the exhaust gas temperature sensor 10 are sent to the control device 15.

  The combustion value for each cylinder is located in a combustible region between the knocking region and the misfire region when normal. Further, the combustion offset of the engine is stabilized by keeping the injection offset value for each cylinder constant unless the exhaust gas temperature fluctuates greatly.

  The control device 15 sets the injection time and the injection offset value based on the measurement values sent, and ignites the ignition timing in the main gas valve 11 using the opening time obtained by adding the injection time and the injection offset value as a command. Send to plug 5.

  Then, the main gas valve 11 is opened by the commanded set value, and the fuel gas is caused to flow into the mixture supply path 8 through the main combustion chamber gas supply pipe 7. The commanded set value is a time for opening the main gas valve 11 or a time for supplying electricity to the main gas valve 11.

  The pre-combustion gas control valve 12 is controlled so as to open and close the pre-combustion gas control valve 12 with a preset opening time based on the engine speed and output, but the injection offset value is irrelevant ( Not set).

  In the combustion control of the engine as described above, the inventor diagnoses the state of the main gas valve 11 by the change of the injection offset value set based on the exhaust gas temperature value and the knocking value sent to the control device 15. I found out that it was data.

  The present invention has been made based on such knowledge, and when the injection offset value increases or decreases, it is determined that the engine is unstable and the main gas valve 11 may be abnormal. To do.

  More specifically, the injection offset value set by the control device 15 is recorded as time history data in the man-machine interface device 16. The recorded time history data (graph) can be viewed from the personal computer 18 in the remote monitoring room 17 via a communication line. FIG. 3 shows an example of time history data viewed on the personal computer 18 in the remote monitoring room 17.

  The injection offset value extracted during one day from the time history data recorded in the man-machine interface device 16 is taken into the personal computer 18 of the remote monitoring room 17 and averaged to obtain one injection offset value (average injection per day). Recorded as an offset value). FIG. 4 shows an example in which the average injection offset value is recorded.

  And when the change of the recorded average injection offset value fluctuates within a desired range (for example, ± 1.0) (for example, between May 1 and July 15 in FIG. 4), it is determined as normal. To do.

  On the other hand, when the change in the average injection offset value starts to decrease or increases and exceeds the desired range (for example, between July 15 and September 20 in FIG. 4), it is determined that the value is abnormally high. To do.

  Based on the determination by the personal computer 18, the operator can make a maintenance plan and take countermeasures, and can prepare for the site.

  By the way, in the above description, the reason why the injection offset value extracted during one day is extracted is that a data collection device is necessary when collecting and capturing a huge amount of data recorded throughout the day. If the equipment breaks down, repair costs or replacement costs will be incurred, so avoiding this and collecting data under certain conditions makes the data collection device unnecessary. is there. Of course, if the purchaser of the gas engine equipment has agreed to install the data collection device, the data collection device may be used.

  The present invention is not limited to the above examples, and it goes without saying that the embodiments may be appropriately changed within the scope of the technical idea described in each claim.

  For example, in the above description, the personal computer 18 in the remote monitoring room 17 determines whether the main gas valve 11 is abnormal or deteriorated, but this determination may be made by an operator who looks at the time history data.

DESCRIPTION OF SYMBOLS 4 Combustion chamber 4a Main combustion chamber 4b Precombustion chamber 7 Main combustion chamber gas supply pipe 8 Mixture supply path 9 Exhaust gas discharge path 10 Exhaust gas temperature sensor 11 Main gas valve 14 Knock sensor 15 Control device 17 Remote monitoring room 18 Personal computer

Claims (2)

A method for diagnosing the state of a main gas valve installed in the middle of a gas supply pipe for a main combustion chamber for supplying fuel gas to an air-fuel mixture supply passage communicating with each cylinder chamber of a gas engine,
A stable combustion state for each cylinder based on the exhaust gas temperature detected by the exhaust gas temperature sensor provided in the exhaust gas exhaust passage of each cylinder of the gas engine and the knocking value detected by the knock sensor provided in each cylinder of the gas engine Collecting the injection offset value, which is a value that adjusts the fuel gas injection time set to keep
The average injection offset value calculating means for calculating the injection offset value for each cylinder as the average injection offset value extracted during the day,
Judgment means for monitoring the fluctuation of the daily average injection offset value calculated by the average injection offset value calculation means and judging whether or not the main gas valve is abnormal,
With
When the average injection offset value calculated by the average injection offset value calculating means starts to decrease or increase and deviates from a predetermined reference range, it is determined that the state of the main gas valve shows a sign of abnormality. A method for diagnosing abnormality and deterioration of a main gas valve for a gas engine. The mean injection offset value, characterized by determining whether using the injection offset value extracted during the day that by averaging the states of the main gas valve showed signs of abnormal A method for diagnosing abnormality and deterioration of a main gas valve for a gas engine according to claim 1.

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