Control device, control method, and program

Abstract

It provides ignition control according to the engine's operating conditions. [Solution] The control device is a control device for a spark plug that ignites the fuel mixture in the cylinder of an engine, and includes a control unit that sets the number of ignitions in one cycle and the discharge energy supplied to the spark plug according to the operating state of the engine.

Description

Technical Field

[0001] The present disclosure relates to a control device, a control method, and a program.

Background Art

[0002] In a premixed gas engine, a spark ignition method using a spark plug is adopted. By applying a voltage of more than ten kV from an ignition coil between the electrodes of the spark plug, the air-fuel mixture is ignited and burned in a short time of about 0.1 msec. Ignition of the air-fuel mixture is affected by external air conditions and operating conditions. Therefore, for the purpose of ensuring reliable ignition and continuous combustion, ignition is often performed multiple times at intervals of about 1 msec.

[0003] Generally, the electrodes of a spark plug to which a high voltage is applied and which is used in a high-temperature environment are consumed as the usage time increases. Also, the rate of consumption varies depending on usage conditions such as intake air pressure, ignition timing, and fuel properties. As the engine's output and efficiency increase, the temperature in the combustion chamber rises and the intake air pressure also tends to increase. In particular, in the latest Miller cycle engine, operation at a high pressure ratio using a high-efficiency supercharger is required. Therefore, the operating environment of the spark plug is becoming more severe.

[0004] The following two factors are known as factors that consume the electrodes of a spark plug. (1) Spark consumption: Consumption in which the discharge part of the electrode is locally melted and scattered by ignition energy. (2) Oxidation consumption: The electrode is consumed due to oxidation and the peeling of the oxide layer at a high ambient temperature. In order to improve the wear resistance of the electrodes, technical improvements have been made by changing the electrode material for spark consumption. On the other hand, for oxidation consumption, countermeasures have been taken by improving the structure of the engine and the spark plug to lower the electrode temperature.

[0005] For example, Patent Document 1 discloses a control method that determines whether ignition has occurred based on the pressure inside the cylinder after ignition by an ignition device and the cylinder pressure calculated by the equation of state, and if it is determined that ignition is complete, it stops the discharge by the spark plug to suppress the number of ignitions. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] International Publication No. 2019 / 064932 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] The quality of ignition of the fuel-air mixture is affected by the engine's operating conditions. For example, if the number of ignitions per cycle can be reduced depending on the operating conditions, electrode wear can be suppressed. Ignition control that is appropriate to the engine's operating conditions is necessary.

[0008] This disclosure provides a control device, a control method, and a program that can solve the above-mentioned problems. [Means for solving the problem]

[0009] The control device of this disclosure is a control device for a spark plug that ignites the fuel mixture in the cylinder of an engine, and comprises a control unit that sets the number of ignitions in one cycle and the discharge energy supplied to the spark plug according to the operating state of the engine. The control unit increases the discharge energy when the combustion state of the engine is unstable compared to when it is not, and if the combustion state of the engine remains unstable even after increasing the discharge energy, it increases the number of ignition cycles.

[0010] The control method disclosed herein is a method for controlling a spark plug that ignites the fuel mixture in the cylinder of an engine, wherein a computer sets the number of ignitions in one cycle and the discharge energy to be supplied to the spark plug according to the operating state of the engine. The system has a step, in which, if the combustion state of the engine is unstable, the discharge energy is increased compared to when it is not, and if the combustion state of the engine is still unstable even after increasing the discharge energy, the number of ignitions is increased. .

[0011] The program of this disclosure is a process for a computer to control a spark plug that ignites the fuel mixture in the cylinder of an engine, and sets the number of ignitions per cycle and the discharge energy to be supplied to the spark plug according to the operating state of the engine. The system has a step, in which, if the combustion state of the engine is unstable, the discharge energy is increased compared to when it is not, and if the combustion state of the engine is still unstable even after increasing the discharge energy, the number of ignitions is increased. Execute the process. [Effects of the Invention]

[0012] According to the control device, control method, and program described above, wear on the spark plug electrodes can be suppressed. [Brief explanation of the drawing]

[0013] [Figure 1] This figure shows an example of a gas engine system according to the embodiment. [Figure 2] This flowchart shows an example of a typical ignition control system. [Figure 3] This figure shows an example of ignition settings according to the embodiment. [Figure 4] This flowchart shows an example of ignition control according to Embodiment 1 of the embodiment. [Figure 5] This flowchart shows an example of ignition control according to Embodiment 2 of the embodiment. [Figure 6] This is a first flowchart showing an example of ignition control according to Embodiment 3 of the embodiment. [Figure 7] This is a second flowchart showing an example of ignition control according to Embodiment 3 of the embodiment. [Figure 8] This is a first flowchart showing an example of ignition control according to Embodiment 4 of the embodiment. [Figure 9] This is a second flowchart showing an example of ignition control according to Embodiment 4 of the embodiment. [Figure 10] This flowchart shows an example of ignition control according to Embodiment 5 of the embodiment. [Figure 11] This flowchart shows an example of ignition control according to Embodiment 6 of the embodiment. [Figure 12]This is a diagram for explaining the ignition control according to Example 7 of the embodiment. [Figure 13] This is a diagram for explaining the ignition control according to Example 8 of the embodiment. [Figure 14] This is a diagram showing an example of the hardware configuration of the control device according to each embodiment.

Mode for Carrying Out the Invention

[0014] <Embodiment> (Configuration) Hereinafter, the ignition control of the present disclosure will be described with reference to FIGS. 1 to 14. FIG. 1 is a diagram showing an example of a system of a gas engine according to an embodiment. The engine system 100 includes a gas engine 10, a generator 20, a gas supply controller 30, an ignition device 40, a combustion diagnosis device 60, a control device 70, and a fuel management device 80.

[0015] The gas engine 10 includes a supercharger 11 and a plurality of cylinders 12a to 12d. An intake air system 11a1 and an exhaust system 19a are connected to the cylinder 12a. The intake air system 11a1 is connected to an air system 11a to which air compressed by the supercharger 11 is supplied and a main chamber fuel gas system 15a to which main chamber fuel gas is supplied. An air-fuel mixture of air and main chamber fuel gas is supplied to a combustion chamber (not shown) in the cylinder 12a through the intake air system 11a1. A valve 16a is provided in the main chamber fuel gas system 15a, and the opening degree of the valve 16a is controlled by the gas supply controller 30. Note that the ignition control of the present embodiment described below is not applicable only to the port injection type gas engine illustrated here, but is also applicable to other types, for example, a type that generates an air-fuel mixture of fuel gas and air before the supercharger 11, or a general gas engine such as a type that injects air and fuel gas separately into the cylinder 12a.

[0016] A sub-chamber 13a, located in cylinder 12a, is connected to a sub-chamber fuel gas system 17a, through which sub-chamber fuel gas is supplied. The sub-chamber 13a is equipped with a spark plug 14a. Ignition occurs when the spark plug 14a is ignited, causing the sub-chamber fuel gas to burn and a flame to form. This flame is blown into the combustion chamber in cylinder 12a, igniting the fuel-air mixture in the combustion chamber and causing combustion. A valve 18a is provided in the sub-chamber fuel gas system 17a. The opening of the valve 18a is controlled by a control device 70. Ignition of the spark plug 14a is performed by an ignition device 40. The ignition device 40 applies fuel to the spark plug 14a according to instructions from the control device 70. While Figure 1 schematically shows one ignition device 40, an ignition device 40 may be provided for each cylinder 12a to 12d. Furthermore, although Figure 1 illustrates a gas engine having a sub-chamber 13a, the ignition control of this embodiment is not only applicable to gas engines with a sub-chamber 13a, but can also be applied to engines without a sub-chamber 13a.

[0017] The exhaust gas after combustion is supplied to the supercharger 11 through the exhaust system 19a and used to rotate the compressor of the supercharger 11.

[0018] The cylinder 12a is equipped with a pressure sensor 1a that detects the pressure inside the combustion chamber (referred to as combustion pressure). The pressure sensor 1a outputs the detected combustion pressure to the combustion diagnostic device 60.

[0019] The above explanation uses cylinder 12a as an example, but the same applies to cylinders 12b to 12d. Although not shown in the diagram, valves 16b to 16d are provided in the main chamber fuel gas systems 15b to 15d, and valves 18b to 18d are provided in the sub-chamber fuel gas systems 17b to 17d. Figure 1 shows a configuration with four cylinders, but the number of cylinders may be three or less, or five or more.

[0020] The generator 20 is driven by the gas engine 10 and generates electricity. The generator 20 is connected to the power grid 21 and supplies the generated electricity to the power grid 21. A circuit breaker 22 is provided in the line connecting the generator 20 and the power grid 21, and the connection and disconnection between the generator 20 and the grid 21 can be switched on (connected) and off (disconnected) by turning the circuit breaker 22 on (connected).

[0021] The gas engine 10 is equipped with an output sensor 23 that detects the output of the gas engine 10. The output value detected by the output sensor 23 is output to the control device 70. Near the gas engine 10, there is a temperature sensor 24 that detects the temperature of the environment in which the gas engine 10 is operating, and a humidity sensor 25 that detects the humidity. The temperature detected by the temperature sensor 24 and the humidity detected by the humidity sensor 25 are output to the control device 70.

[0022] The combustion diagnostic device 60 acquires the combustion pressure detected by pressure sensors 1a to 1d and diagnoses the combustion state of each cylinder 12a to 12d. For example, the combustion diagnostic device 60 monitors the peak value of the combustion pressure in one engine cycle (intake, compression, combustion, and exhaust processes), and diagnoses that the combustion pressure is decreasing if the peak value of the combustion pressure falls below a threshold for a predetermined number of times, either continuously or intermittently, over several cycles. The combustion diagnostic device 60 also diagnoses that flame suppression or misfire has occurred if flame suppression or misfire is detected for a predetermined number of times, either continuously or intermittently, over several cycles. Any known method can be applied to diagnose flame suppression or misfire. For example, methods are known that diagnose based on the combustion pressure detected by pressure sensor 1a, or methods that diagnose based on the combustion pressure detected by pressure sensor 1a and the crank angle detected by a crank angle detector (not shown). The combustion diagnostic device 60 outputs the diagnostic results of the combustion state of each cylinder 12a to 12d (normal, decreased combustion pressure, extinction, misfire, etc.) to the control device 70.

[0023] The control device 70 controls the gas engine 10. The control device 70 comprises an acquisition unit 71, a control unit 72, and a storage unit 73.

[0024] The acquisition unit 71 acquires the output value detected by the output sensor 23, the temperature detected by the temperature sensor 24, the humidity detected by the humidity sensor 25, the combustion status of each cylinder 12a to 12d diagnosed by the combustion diagnostic device 60, the on / off signal of the circuit breaker 22, and fuel gas information output by the fuel management device 80.

[0025] The control unit 72 controls the gas supply controller 30 to adjust the amount of gas fuel supplied to the main chambers 12a to 12d, controls the valve 16a, etc. to adjust the amount of gas fuel supplied to the sub-chambers 13a to 13d, and controls the turbocharger 11, etc., thereby performing air-fuel ratio control.

[0026] Furthermore, the control unit 72 controls the ignition of the spark plugs 14a to 14d by controlling the ignition device 40. Normally, the control unit 72 outputs control signals to the ignition device 40 to instruct the start and end of ignition and the ignition timing, but in this embodiment, in addition to these, it also instructs the number of ignitions and the discharge energy of the spark plugs. Discharge energy is the value obtained by integrating the voltage × current over time when the electromagnetic energy stored in the secondary coil of the ignition device 40 is released (induced discharge). The reason for instructing the number of ignitions and the discharge energy is to suppress electrode wear of the spark plugs by changing the number of ignitions and the discharge energy according to the operating state and combustion state of the gas engine 10. For example, in the low-load range of the engine, combustion tends to become unstable because the combustion chamber temperature decreases, so multiple ignitions are performed to stabilize ignition. On the other hand, in the high-load range, good combustion can often be obtained with a single ignition, so only one ignition is performed. The control unit 72 adjusts the ignition frequency and discharge energy according to the engine's operating state to achieve both stable combustion and reduced spark plug wear.

[0027] The memory unit 73 stores various information necessary for control. For example, the memory unit 73 stores detection values ​​from various sensors acquired by the acquisition unit 71, diagnostic results of the combustion state for each cylinder and whether or not abnormal combustion has occurred, and information about the fuel gas (for example, what type of fuel gas it is, whether or not the fuel gas has been switched to a different type of fuel gas, etc.).

[0028] (Examples of typical behavior) Next, with reference to Figure 2, an example of a typical ignition control system, such as a spark plug 14a, will be explained. The control device 70 starts the gas engine 10 (step S1). The control unit 72 sets the number of ignitions to 2 and the discharge energy to a predetermined value (referred to as setting A), and instructs the ignition device 40 to perform ignition control under these conditions. Note that 2 ignitions is just an example, and there may be more than 2 ignitions. This is also true in the following embodiments ("described as 2 (or more)"). The ignition device 40 applies a high voltage to the spark plugs 14a to 14d with an ignition setting of 2 ignitions per cycle and discharge energy of setting A, and ignites the spark plugs 14a to 14d (step S2). For example, the ignition device 40 applies the voltage to the spark plugs 14a to 14d twice at an interval of 1 msec. The control unit 72 instructs the ignition device 40 to ignite with the same ignition setting each time. From this point onward, the ignition device 40 ignites the spark plugs 14a to 14d with an ignition setting of 2 ignitions and a discharge energy of setting A in each cycle.

[0029] Generally, as explained in Figure 2, the spark plug 14a is ignited with the same ignition setting each time. However, if ignition is performed every cycle with an ignition setting that ensures reliable ignition under any environmental or operating conditions, electrode wear cannot be suppressed. Therefore, in this embodiment, the ignition setting for the spark plug 14a is switched to one of ignition settings 1 to 4 in the setting table 300 shown in Figure 3, depending on the output and combustion state of the gas engine 10, thereby suppressing electrode wear of the spark plug. An example of ignition control using ignition settings 1 to 4 is shown below.

[0030] (Example 1) Figure 4 is a flowchart showing an example of ignition control according to Embodiment 1 of the embodiment. The control device 70 starts the gas engine 10 (step S11). The control unit 72 acquires the output of the gas engine 10 detected by the output sensor 23 through the acquisition unit 71 and determines whether the output is below the output range that can be considered a high load (step S12). The output range that can be considered a high load is, for example, the output range of 80% or more of the rated output. (Hereafter, an output below the output range that can be considered a high load will be described as "less than high load," and an output above the output range that can be considered a high load will be described as "high load or more.") If the output of the gas engine 10 is less than high load (step S12; Yes), the control unit 72 sets the number of ignitions in one cycle to 2 (multiple times), sets the discharge energy to setting A (ignition setting 3), and instructs the ignition device 40 to perform ignition control with ignition setting 3. The ignition device 40 ignites the spark plugs 14a to 14d based on ignition setting 3 (step S14). When the engine output is below high load, combustion tends to become unstable due to a decrease in combustion chamber temperature. Therefore, multiple ignitions are performed without changing the discharge energy setting.

[0031] If the engine output is above high load (step S12; No), the control unit 72 obtains the combustion state diagnosis results of cylinders 12a to 12d from the combustion diagnostic device 60 via the acquisition unit 71 and determines whether the combustion is unstable (step S13). For example, if the diagnosis result is that the combustion pressure is low, flame extinction is occurring, or misfires are occurring, the control unit 72 determines that the combustion is unstable; otherwise, it determines that the combustion is not unstable.

[0032] If combustion is determined to be unstable (step S13; Yes), the control unit 72 sets the number of ignitions per cycle to 2 (multiple times) and the discharge energy to setting A for the cylinder among cylinders 12a to 12d that is determined to have unstable combustion (ignition setting 3). Based on ignition setting 3, the ignition device 40 ignites the spark plug 14x of the cylinder 12x (x is one or more of a to d, the same applies hereinafter) that is determined to have unstable combustion (step S14). If combustion is unstable, multiple ignitions stabilize the combustion.

[0033] If it is determined that combustion is not unstable (step S13; No), the control unit 72 sets the number of ignitions per cycle to 1 and the discharge energy to setting A for the cylinders among cylinders 12a to 12d that are determined to have stable combustion (ignition setting 1). Based on ignition setting 1, the ignition device 40 ignites the spark plug 14x of the cylinder that is determined to have stable combustion (step S15). When the output of the gas engine 10 is high and combustion is stable, it is expected that good combustion can be obtained with one ignition, so the number of ignitions is set to 1 to suppress electrode wear.

[0034] The control unit 72 repeats the processing from step S12 onward in subsequent cycles. This suppresses wear on the electrodes of the spark plugs 14a to 14d while achieving stable combustion.

[0035] Figure 4 illustrates the control of the gas engine 10 by combining its output and combustion state. However, the number of ignitions may also be controlled by the output alone or by the combustion state alone. For example, in the case of controlling only the output, if the output of the gas engine 10 is above high load, the number of ignitions is set to 1 and the discharge energy to A (ignition setting 1). If the output is below high load, the number of ignitions is set to 2 (multiple times) and the discharge energy to A (ignition setting 3) to ignite the spark plug 14a, etc. For example, in the case of controlling only the combustion state, if the combustion state of the gas engine 10 is not unstable, the number of ignitions is set to 1 and the discharge energy to A (ignition setting 1). If the combustion state is unstable, the number of ignitions is set to 2 (multiple times) and the discharge energy to A (ignition setting 3) to ignite the spark plug 14a, etc.

[0036] (Example 2) Figure 5 is a flowchart showing an example of ignition control according to Embodiment 2 of the embodiment. The flowchart in Figure 5 shows the control of the engine over a time range of each cycle (e.g., 160 msec) or several cycles (in seconds). The control device 70 starts the gas engine 10 (step S21). The control unit 72 determines whether the output of the gas engine 10 is below high load (step S22). This determination is the same as in step S12 in Figure 4. This is also the case in the following embodiments. If the output of the gas engine 10 is below high load (step S22; Yes), the control unit 72 sets the number of ignitions in one cycle to 2 (multiple times), the discharge energy to setting A (ignition setting 3), and instructs the ignition device 40 to perform ignition control with ignition setting 3. The ignition device 40 ignites the spark plugs 14a to 14d based on ignition setting 3 (step S23). After performing ignition control based on ignition setting 3, the control unit 72 determines whether the combustion of each cylinder 12a, etc. is unstable based on the diagnosis results from the combustion diagnosis device 60 (step S24). This determination is the same as in step S13 in Figure 4. This is also the case in the following embodiments. If the control unit 72 determines that combustion is not unstable (step S24; No), it sets the ignition setting to 3 for the cylinder 12x among the cylinders 12a to 12d that it determined to have stable combustion. Based on the ignition setting 3, the ignition device 40 ignites the spark plug 14x of the cylinder 12x that does not have unstable combustion (step S25). The control unit 72 repeats the process from step S22 onwards in subsequent cycles.

[0037] If the control unit 72 determines that combustion is unstable (step S24; Yes), it sets the number of ignitions per cycle to 2 (multiple times) and the discharge energy to setting B (ignition setting 4) for the cylinder 12x whose combustion is deemed unstable. Setting B is a higher discharge energy setting than setting A. Based on ignition setting 4, the ignition device 40 ignites the spark plug 14x of the cylinder 12x whose combustion is deemed unstable (step S26). The control unit 72 repeats the process from step S22 onwards in subsequent cycles.

[0038] If the output is above high load (step S22; No), the control unit 72 sets the number of ignitions per cycle to 1 and the discharge energy to setting A (ignition setting 1). Based on ignition setting 1, the ignition device 40 ignites the spark plugs 14a to 14d (step S27). After performing ignition control based on ignition setting 1, the control unit 72 determines whether the combustion of each cylinder 12a, etc. is unstable based on the diagnosis results from the combustion diagnosis device 60 (step S28). If it is determined that the combustion is not unstable (step S28; No), the control unit 72 sets ignition setting 1 for the cylinder 12x among the cylinders 12a to 12d that was determined to have stable combustion. Based on ignition setting 1, the ignition device 40 ignites the spark plug 14x of the cylinder 12x that does not have unstable combustion (step S297). The control unit 72 repeats the process from step S22 onwards in subsequent cycles.

[0039] If the combustion is determined to be unstable (step S28; Yes), the control unit 72 sets the number of ignitions per cycle to 1 and the discharge energy to setting B (ignition setting 2) for the cylinder 12x whose combustion is determined to be unstable. Based on ignition setting 2, the ignition device 40 ignites the spark plug 14x of the cylinder 12x whose combustion is determined to be unstable (step S29). When ignition control is performed based on ignition setting 2, the control unit 72 determines whether the combustion of the cylinder 12a, etc., which is the subject of processing in step S29, is unstable, based on the diagnosis result from the combustion diagnostic device 60 (step S291). If the combustion is determined not to be unstable (step S291; No), the control unit 72 sets ignition setting 2 for the cylinder 12x whose combustion is determined not to be unstable, and the ignition device 40 ignites the spark plug 14x of the cylinder 12x whose combustion is not unstable, based on ignition setting 2 (step S296). The control unit 72 will continue to repeat the processing from step S22 onward in subsequent cycles.

[0040] If the combustion is determined to be unstable (step S291; Yes), the control unit 72 sets the number of ignitions per cycle to 2 (multiple times) and the discharge energy to setting A (ignition setting 3) for the cylinder 12x that was determined to have unstable combustion among those targeted in step S29. Based on ignition setting 3, the ignition device 40 ignites the spark plug 14x of the cylinder 12x that was determined to have unstable combustion (step S292). After performing ignition control based on ignition setting 3, the control unit 72 again determines whether the combustion of the cylinder 12a, etc., that was processed in step S292 is unstable, based on the diagnosis result from the combustion diagnostic device 60 (step S293). If the combustion is determined not to be unstable (step S293; No), the control unit 72 sets ignition setting 3 for the cylinder 12x that was determined not to have unstable combustion. The ignition device 40 ignites the spark plugs 14x of cylinders 12x whose combustion is not unstable, based on the ignition setting 3 (step S294). The control unit 72 repeats the process from step S22 onwards in subsequent cycles.

[0041] If the control unit 72 determines that combustion is unstable (step S293; Yes), it sets the number of ignitions per cycle to 2 (multiple times) and the discharge energy to setting B (ignition setting 4) for the cylinder 12x whose combustion is deemed unstable. Based on ignition setting 4, the ignition device 40 ignites the spark plug 14x of the cylinder 12x whose combustion is deemed unstable (step S295). The control unit 72 repeats the process from step S22 onwards in subsequent cycles.

[0042] As shown in the flowchart in Figure 5, the ignition settings are switched according to the load, and if combustion is unstable, the discharge energy is increased to stabilize combustion. If combustion remains unstable even after increasing the discharge energy, the number of ignitions is increased to stabilize combustion. More specifically, to address combustion instability, the ignition setting level in the setting table 300 in Figure 3 is increased one level at a time to stabilize combustion. This approach is also applied to the following examples 3 to 7.

[0043] (Example 3) Figures 6 and 7 are flowcharts showing an example of ignition control according to Embodiment 3 of the embodiment. Unlike Example 2, Example 3 involves control over a time range of minutes. First, refer to Figure 6. The control unit 72 executes the process shown in Figure 6 at a predetermined control cycle (in minutes) while the engine 10 is running.

[0044] The control unit 72 determines whether an unstable combustion state has occurred for a long period of time (step S311). The control unit 72 records the diagnostic result of the combustion diagnostic device 60 in the storage unit 73, corresponding to the time the diagnostic result was obtained. Then, the control unit 72 refers to the diagnostic result recorded in the storage unit 73 and, for example, if the diagnostic result of the combustion diagnostic device 60 indicates that the combustion pressure has decreased, flame extinction has occurred, or misfire has occurred for a predetermined period of time or longer (or a predetermined number of times or longer), the control unit 72 determines that an unstable combustion state has occurred for a long period of time; otherwise, it determines that the combustion state has not been unstable for a long period of time. If it is determined that an unstable combustion state has occurred for a long period of time (step S311; Yes), the control unit 72 sets a flag, which has an initial value of 0, to 1 (step S313). If it is determined that an unstable combustion state has not occurred for a long period of time (step S311; No), the control unit 72 sets the flag to 0 (step S312).

[0045] In parallel with the process in Figure 6, the control unit 72 executes the flowchart in Figure 7. In each block of the flowchart in Figure 7, the ignition setting described in the upper section is the process when the flag is set to 0. The ignition setting described in the lower section in parentheses is the process when the flag is set to 1. While the process in Figure 6 is executed every minute, the flowchart in Figure 7 is executed every engine cycle or every few cycles.

[0046] • If the combustion state is not unstable for an extended period (flag=0) First, let's explain the case where the flag is set to 0 (i.e., when an unstable combustion state has not occurred for a long period of time). Since most of the processing when the flag is set to 0 is the same as in Example 2, we will explain it briefly.

[0047] The control device 70 starts the gas engine 10 (step S31). The control unit 72 determines whether the output of the gas engine 10 is below high load (step S32). If the output of the gas engine 10 is below high load (step S32; Yes), the control unit 72 sets ignition setting 3. The ignition device 40 ignites the spark plugs 14a, etc., based on ignition setting 3 (step S33). After performing ignition control based on ignition setting 3, the control unit 72 determines whether the combustion is unstable (step S34). If it is determined that the combustion is not unstable (step S34; No), the control unit 72 sets ignition setting 3 for the cylinders 12x for which it was determined that the combustion is not unstable. The ignition device 40 ignites the spark plugs 14x of these cylinders 12x based on ignition setting 3 (step S35). The control unit 72 proceeds to the process of step S398, which will be described later.

[0048] If the control unit 72 determines that combustion is unstable (step S34; Yes), it sets the ignition setting 4 for the cylinder 12x that was determined to have unstable combustion. Based on the ignition setting 4, the ignition device 40 ignites the spark plugs 14x of these cylinders 12x (step S36). The control unit 72 then proceeds to the process of step S398, which will be described later.

[0049] If the output is above high load (step S32; No), the control unit 72 sets ignition setting 1, and the ignition device 40 ignites the spark plugs 14a to 14d based on ignition setting 1 (step S37). Next, the control unit 72 determines whether the combustion of each cylinder 12a, etc. is unstable (step S38). If it is determined that the combustion is not unstable (step S38; No), the control unit 72 sets ignition setting 1 for the cylinder 12x that was determined to have stable combustion, and the ignition device 40 ignites the spark plug 14x of the cylinder 12x that has not had unstable combustion based on ignition setting 1 (step S397). The control unit 72 then proceeds to the process of step S398, which will be described later.

[0050] If the control unit 72 determines that combustion is unstable (step S38; Yes), it sets ignition setting 2 for the cylinder 12x that was determined to have unstable combustion. Based on ignition setting 2, the ignition device 40 ignites the spark plug 14x of the cylinder 12x with unstable combustion (step S39). Next, the control unit 72 determines whether the combustion of the cylinder 12a, etc., that was processed in step S39 is unstable (step S391). If the control unit 72 determines that combustion is not unstable (step S391; No), it sets ignition setting 2 for the cylinder 12x that was determined to have stable combustion, and the ignition device 40 ignites the spark plug 14x of these cylinders 12x based on ignition setting 2 (step S396). The control unit 72 proceeds to the process in step S398, which will be described later.

[0051] If the control unit 72 determines that combustion is unstable (step S391; Yes), it sets the ignition setting to 3 for the cylinder 12x that was determined to have unstable combustion. The ignition device 40 ignites the spark plugs 14x of these cylinders 12x based on the ignition setting 3 (step S392). Next, the control unit 72 determines whether the combustion of the cylinder 12a, etc. that was processed in step S392 is unstable (step S393). If the control unit 72 determines that combustion is not unstable (step S393; No), it sets the ignition setting to 3 for the cylinder 12x that was determined to have stable combustion. The ignition device 40 ignites the spark plugs 14x of these cylinders 12x based on the ignition setting 3 (step S394). The control unit 72 proceeds to the process of step S398, which will be described later.

[0052] If the control unit 72 determines that combustion is unstable (step S393; Yes), it sets the ignition setting 4 for the cylinder 12x that was determined to have unstable combustion. The ignition device 40 ignites these spark plugs 14x based on the ignition setting 4 (step S395). The control unit 72 then proceeds to step S398.

[0053] Next, the control unit 72 determines whether the long-term combustion is unstable (step S398). The control unit 72 records the diagnosis result of the combustion diagnostic device 60 in the storage unit 73, corresponding to the time the diagnosis result was obtained. Then, the control unit 72 refers to the diagnosis result recorded in the storage unit 73 and, for example, if the diagnosis result of the combustion diagnostic device 60 indicates that the combustion pressure has decreased, flame extinction has occurred, or misfire has occurred for a predetermined time or longer (or a predetermined number of times or longer), the control unit 72 determines that the long-term combustion is unstable; otherwise, it determines that the long-term combustion is not unstable. The long time in step S398 and the long time in step S311 in Figure 6 may be the same or different. The determination in step S398 is performed more frequently than in step S311 in Figure 6. If it is determined that the long-term combustion is unstable (step S398; Yes), the control unit 72 sets the flag to 1 (step S399). The control unit 72 repeats the processing from step S32 onwards in subsequent cycles. If it determines that combustion is not stable for a certain period of time (step S398; No), the control unit 72 repeats the processing from step S32 onwards without changing the flag.

[0054] For example, if the process in Figure 6 is executed in parallel with the process in Figure 7 and the flag value changes from 0 to 1, the process may be switched to the process for when the flag is set to 1 when the process from step S32 is started anew, or the lower ignition setting may be applied from the first block executed after the flag changes from 0 to 1. Similarly, if the flag value changes from 1 to 0 while the process in Figure 7 is being executed, the process may be switched to the process for when the flag is set to 0 when the process from step S32 is started anew, or the upper ignition setting may be applied from the first block executed after the flag changes from 1 to 0.

[0055] • If the combustion state remains unstable for an extended period (flag=1) Next, we will explain the process when the flag is set to 1 (when an unstable combustion state occurs for a long period of time). When the flag is set to 1, the ignition setting level, which is the same as when the flag is 0, is increased by one (for example, if the ignition setting is 1 when the flag is 0, it will be set to ignition setting 2), and the ignition setting is determined in the same way as when the flag is 0. The process when the flag is set to 1 is the same as when the flag is set to 0, except for the ignition setting level, so we will explain it briefly.

[0056] The control device 70 starts the gas engine 10 (step S31). The control unit 72 determines whether the output of the gas engine 10 is below high load (step S32). If the output of the gas engine 10 is below high load (step S32; Yes), the control unit 72 sets the ignition setting 4. The ignition device 40 ignites the spark plugs 14a, etc., based on the ignition setting 4 (step S33). Next, the control unit 72 determines whether the combustion is unstable (step S34). If it is determined that the combustion is not unstable (step S34; No), the control unit 72 sets the ignition setting 4 for the cylinders 12x for which it was determined that the combustion is not unstable. The ignition device 40 ignites the spark plugs 14x of these cylinders 12x based on the ignition setting 4 (step S35). The control unit 72 proceeds to the process in step S398.

[0057] If the control unit 72 determines that combustion is unstable (step S34; Yes), it sets the ignition setting 4 for the cylinder 12x that was determined to have unstable combustion. Based on the ignition setting 4, the ignition device 40 ignites the spark plugs 14x of these cylinders 12x (step S36). The control unit 72 then proceeds to step S398.

[0058] If the output is above high load (step S32; No), the control unit 72 sets ignition setting 2, and the ignition device 40 ignites the spark plugs 14a to 14d based on ignition setting 2 (step S37). Next, the control unit 72 determines whether the combustion of each cylinder 12a, etc. is unstable (step S38). If it is determined that the combustion is not unstable (step S38; No), the control unit 72 sets ignition setting 2 for the cylinder 12x that was determined to have stable combustion, and the ignition device 40 ignites the spark plug 14x of the cylinder 12x that has not had unstable combustion based on ignition setting 2 (step S397). The control unit 72 then proceeds to step S398.

[0059] If the control unit 72 determines that the combustion is unstable (step S38; Yes), it sets the ignition setting to 3 for the cylinder 12x whose combustion is unstable, and the ignition device 40 ignites the spark plug 14x of the cylinder 12x with unstable combustion based on the ignition setting 3 (step S39). Next, the control unit 72 determines whether the combustion of the cylinder 12a, etc., that was processed in step S39 is unstable (step S391). If the control unit 72 determines that the combustion is not unstable (step S391; No), it sets the ignition setting to 3 for the cylinder 12x whose combustion is not unstable, and the ignition device 40 ignites the spark plug 14x of these cylinders 12x based on the ignition setting 3 (step S396). The control unit 72 proceeds to the process in step S398.

[0060] If the control unit 72 determines that combustion is unstable (step S391; Yes), it sets the ignition setting 4 for the cylinder 12x with unstable combustion. The ignition device 40 ignites the spark plugs 14x of these cylinders 12x based on the ignition setting 4 (step S392). Next, the control unit 72 determines whether the combustion of the cylinder 12a, etc. that was processed in step S392 is unstable (step S393). If the control unit 72 determines that combustion is not unstable (step S393; No), it sets the ignition setting 4 for the cylinder 12x that was determined not to have unstable combustion. The ignition device 40 ignites the spark plugs 14x of these cylinders 12x based on the ignition setting 4 (step S394). The control unit 72 proceeds to the process in step S398.

[0061] If the control unit 72 determines that combustion is unstable (step S393; Yes), it sets the ignition setting 4 for the cylinder 12x that was determined to have unstable combustion. The ignition device 40 ignites these spark plugs 14x based on the ignition setting 4 (step S395). The control unit 72 then proceeds to step S398.

[0062] Next, the control unit 72 determines whether the long-term combustion is unstable (step S398). If it determines that the long-term combustion is unstable (step S398; Yes), the control unit 72 sets the flag to 1 (step S399). The control unit 72 repeats the process from step S22 onwards. If it determines that the combustion is not stable for a certain period of time (step S398; No), the control unit 72 repeats the process from step S32 onwards.

[0063] (Example 4) Figures 8 and 9 are flowcharts showing an example of ignition control according to Embodiment 4 of the embodiment. First, refer to Figure 8. The control unit 72 executes the process shown in Figure 8 at a predetermined control cycle while the engine 10 is running. The control unit 72 determines whether the fuel gas properties are outside the standard range (step S411). The control unit 72 acquires information on the fuel gas (main chamber fuel gas and sub-chamber fuel gas) from the fuel management device 80 through the acquisition unit 71. If the gaseous fuel is a low-calorie fuel or a fuel with a low calorific value such as hydrogen fuel, the control unit 72 determines that the fuel gas properties are outside the standard range; otherwise, it determines that the fuel gas properties are not outside the standard range.

[0064] If the fuel gas properties are determined to be outside the standard range (step S411; Yes), the control unit 72 sets the flag, which has an initial value of 0, to 1 (step S413). If the fuel gas properties are determined to be not outside the standard range (step S411; No), the control unit 72 sets the flag to 0 (step S412).

[0065] In parallel with the process shown in Figure 8, the control unit 72 executes the flowchart shown in Figure 9. In each block of the flowchart in Figure 9, the ignition setting described in the upper section is the process when the flag is set to 0. The ignition setting in parentheses in the lower section is the process when the flag is set to 1.

[0066] • When the properties of the fuel gas are not outside the standard range. First, let's explain the case where the flag is set to 0. The processing when the flag is set to 0 is the same as in Example 2, so we will explain it briefly.

[0067] The control device 70 starts the gas engine 10 (step S41). The control unit 72 determines whether the output of the gas engine 10 is below high load (step S42). If the output is below high load (step S42; Yes), the control unit 72 sets ignition setting 3. The ignition device 40 ignites the spark plugs 14a, etc., based on ignition setting 3 (step S43). Next, the control unit 72 determines whether the combustion is unstable (step S44). If it determines that the combustion is not unstable (step S44; No), the control unit 72 sets ignition setting 3 for the cylinders 12x for which it determined the combustion was not unstable. The ignition device 40 ignites the spark plugs 14x of these cylinders 12x based on ignition setting 3 (step S45). The control unit 72 repeats the process from step S42 onward.

[0068] If the control unit 72 determines that combustion is unstable (step S44; Yes), it sets the ignition setting 4 for the cylinder 12x that was determined to have unstable combustion. The ignition device 40 ignites the spark plugs 14x of these cylinders 12x based on the ignition setting 4 (step S46). The control unit 72 repeats the process from step S42 onward.

[0069] If the output is above high load (step S42; No), the control unit 72 sets ignition setting 1, and the ignition device 40 ignites the spark plugs 14a to 14d based on ignition setting 1 (step S47). Next, the control unit 72 determines whether the combustion of each cylinder 12a, etc. is unstable (step S48). If it is determined that the combustion is not unstable (step S48; No), the control unit 72 sets ignition setting 1 for the cylinder 12x that was determined to have stable combustion, and the ignition device 40 ignites the spark plug 14x of the cylinder 12x that has not had unstable combustion based on ignition setting 1 (step S497). The control unit 72 repeats the process from step S42 onward.

[0070] If the control unit 72 determines that combustion is unstable (step S48; Yes), it sets ignition setting 2 for the cylinder 12x that was determined to have unstable combustion. Based on ignition setting 2, the ignition device 40 ignites the spark plug 14x of the cylinder 12x with unstable combustion (step S49). Next, the control unit 72 determines whether the combustion of the cylinder 12a, etc., that was the subject of step S49 is unstable (step S491). If the control unit 72 determines that combustion is not unstable (step S491; No), it sets ignition setting 2 for the cylinder 12x that was determined to have stable combustion, and the ignition device 40 ignites the spark plug 14x of these cylinders 12x based on ignition setting 2 (step S496). The control unit 72 repeats the process from step S42 onward.

[0071] If the control unit 72 determines that combustion is unstable (step S491; Yes), it sets the ignition setting to 3 for the cylinder 12x that was determined to have unstable combustion. The ignition device 40 ignites the spark plugs 14x of these cylinders 12x based on the ignition setting 3 (step S492). Next, the control unit 72 determines whether the combustion of the cylinder 12a, etc. that was processed in step S492 is unstable (step S493). If the control unit 72 determines that combustion is not unstable (step S493; No), it sets the ignition setting to 3 for the cylinder 12x that was determined to have stable combustion. The ignition device 40 ignites the spark plugs 14x of these cylinders 12x based on the ignition setting 3 (step S494). The control unit 72 repeats the process from step S42 onward.

[0072] If the control unit 72 determines that combustion is unstable (step S493; Yes), it sets the ignition setting 4 for the cylinder 12x that was determined to have unstable combustion. The ignition device 40 ignites these spark plugs 14x based on the ignition setting 4 (step S495). The control unit 72 repeats the process from step S42 onward.

[0073] While the process in Figure 9 is being performed, the process in Figure 8 is executed in parallel. If the flag value changes from 0 to 1 during the process in Figure 8, the process may be switched to the process for when the flag is set to 1 at the timing when the process from step S42 starts anew, or the lower ignition setting may be applied from the first block executed after the flag changes from 0 to 1. Similarly, if the flag value changes from 1 to 0 due to the process in Figure 8 while the process in Figure 9 is being performed, the process may be switched to the process for when the flag is set to 0 at the timing when the process from step S42 starts anew, or the upper ignition setting may be applied from the first block executed after the flag changes from 1 to 0.

[0074] • If the properties of the fuel gas are outside the standard range. Next, we will explain the process when the flag is set to 1. The process when the flag is set to 1 is the same as when the flag is set to 0, with only the ignition setting level being different, so we will explain it briefly.

[0075] The control device 70 starts the gas engine 10 (step S41). The control unit 72 determines whether the output of the gas engine 10 is below high load (step S42). If the output is below high load (step S42; Yes), the control unit 72 sets the ignition setting 4. The ignition device 40 ignites the spark plugs 14a, etc., based on the ignition setting 4 (step S43). Next, the control unit 72 determines whether the combustion is unstable (step S44). If it determines that the combustion is not unstable (step S44; No), the control unit 72 sets the ignition setting 4 for the cylinders 12x for which it was determined that the combustion is not unstable. The ignition device 40 ignites the spark plugs 14x of these cylinders 12x based on the ignition setting 4 (step S45). The control unit 72 repeats the process from step S42 onward.

[0076] If the control unit 72 determines that combustion is unstable (step S44; Yes), it sets the ignition setting 4 for the cylinder 12x that was determined to have unstable combustion. The ignition device 40 ignites the spark plugs 14x of these cylinders 12x based on the ignition setting 4 (step S46). The control unit 72 repeats the process from step S42 onward.

[0077] If the output is above high load (step S42; No), the control unit 72 sets ignition setting 2, and the ignition device 40 ignites the spark plugs 14a to 14d based on ignition setting 2 (step S47). Next, the control unit 72 determines whether the combustion of each cylinder 12a, etc. is unstable (step S48). If it is determined that the combustion is not unstable (step S48; No), the control unit 72 sets ignition setting 2 for the cylinder 12x that was determined to have stable combustion, and the ignition device 40 ignites the spark plug 14x of the cylinder 12x that has not had unstable combustion based on ignition setting 2 (step S497). The control unit 72 repeats the process from step S42 onward.

[0078] If the control unit 72 determines that combustion is unstable (step S48; Yes), it sets the ignition setting to 3 for the cylinder 12x whose combustion is unstable, and the ignition device 40 ignites the spark plug 14x of the cylinder 12x with unstable combustion based on the ignition setting 3 (step S49). Next, the control unit 72 determines whether the combustion of the cylinder 12a, etc., which was processed in step S49, is unstable (step S491). If the control unit 72 determines that combustion is not unstable (step S491; No), it sets the ignition setting to 3 for the cylinder 12x whose combustion is not unstable, and the ignition device 40 ignites the spark plug 14x of these cylinders 12x based on the ignition setting 3 (step S496). The control unit 72 repeats the process from step S42 onward.

[0079] If the control unit 72 determines that combustion is unstable (step S491; Yes), it sets the ignition setting 4 for the cylinder 12x with unstable combustion. The ignition device 40 ignites the spark plugs 14x of these cylinders 12x based on the ignition setting 4 (step S492). Next, the control unit 72 determines whether the combustion of the cylinder 12a, etc. that was processed in step S492 is unstable (step S493). If the control unit 72 determines that combustion is not unstable (step S493; No), it sets the ignition setting 4 for the cylinder 12x that was determined not to have unstable combustion. The ignition device 40 ignites the spark plugs 14x of these cylinders 12x based on the ignition setting 4 (step S494). The control unit 72 repeats the process from step S42 onward.

[0080] If the control unit 72 determines that combustion is unstable (step S493; Yes), it sets the ignition setting 4 for the cylinder 12x that was determined to have unstable combustion. The ignition device 40 ignites these spark plugs 14x based on the ignition setting 4 (step S495). The control unit 72 repeats the process from step S42 onward.

[0081] (Example 5) Figure 10 is a flowchart showing an example of ignition control according to Embodiment 5 of the embodiment. The control unit 72 executes the process shown in Figure 10 at a predetermined control cycle while the engine 10 is running. The control unit 72 determines whether the outside temperature or humidity is outside the reference range (step S511). The control unit 72 acquires the outside temperature detected by the temperature sensor 24 and the humidity detected by the humidity sensor 25 through the acquisition unit 71. If the outside temperature or humidity is outside the reference range (specifically, if the outside temperature is lower than the threshold and / or the humidity is higher than the threshold), the control unit 72 determines that the outside temperature or humidity is outside the reference range; otherwise, it determines that the outside temperature and humidity are not outside the reference range.

[0082] If the outside temperature or humidity is determined to be outside the reference range (step S511; Yes), the control unit 72 sets a flag, which has an initial value of 0, to 1 (step S513). If the outside temperature and humidity are determined to be not outside the reference range (step S511; No), the control unit 72 sets the flag to 0 (step S512).

[0083] In parallel with the process shown in Figure 10, the control unit 72 executes the flowchart shown in Figure 9. In each block of the flowchart in Figure 9, the ignition setting described in the upper section is the process when the flag is set to 0. The ignition setting in parentheses in the lower section is the process when the flag is set to 1.

[0084] • When the outside temperature or humidity is not outside the standard range. In this case, the control device 70 performs the same processing as in Example 4, "when the properties of the fuel gas are not outside the standard range."

[0085] • If the outside temperature or humidity is outside the standard range. In this case, the control device 70 performs the same processing as in Example 4, "when the properties of the fuel gas are outside the standard range."

[0086] (Example 6) Figure 11 is a flowchart showing an example of ignition control according to Embodiment 6 of the embodiment. The control unit 72 executes the process shown in Figure 11 at a predetermined control cycle while the engine 10 is running. The control unit 72 determines whether an unstable combustion state has occurred for a long period of time (step S611). This process is the same as step S311 in Figure 6. If it is determined that an unstable combustion state has occurred for a long period of time (step S611; Yes), the control unit 72 sets the flag to 1 (step S615). If it is determined that an unstable combustion state has not occurred for a long period of time (step S611; No), the control unit 72 determines whether the fuel gas properties are outside the standard range (step S612). This process is the same as step S411 in Figure 8. If it is determined that the fuel gas properties are outside the standard range (step S612; Yes), the control unit 72 sets the flag to 1 (step S615). If it is determined that the fuel gas properties are not outside the standard range (step S612; No), the control unit 72 determines whether the outside temperature or humidity is outside the standard range (step S613). This process is the same as step S511 in Figure 10. If the outside temperature or humidity is determined to be outside the reference range (step S613; Yes), the control unit 72 sets the flag to 1 (step S615). If the outside temperature and humidity are determined to be not outside the reference range (step S613; No), the control unit 72 sets the flag to 0 (step S512).

[0087] In parallel with the process shown in Figure 10, the control unit 72 executes the flowchart shown in Figure 7. In each block of the flowchart in Figure 7, the ignition setting described in the upper section is the process when the flag is set to 0. The ignition setting in parentheses in the lower section is the process when the flag is set to 1.

[0088] • If the flag is set to 0 In this case, the control device 70 performs the same processing as in Example 3, "when the combustion state is not unstable for a long period of time."

[0089] If the flag is set to 1 In this case, the control device 70 performs the same processing as in Example 3, "when the combustion state is unstable for a long period of time."

[0090] Figure 12 is a diagram illustrating the ignition control according to Embodiment 7 of the embodiment. Referring to Figure 12, the ignition control during load application will be explained. Graph 801 in Figure 12 shows the change in required power output. Graph 802 shows the change in the number of ignitions and discharge energy. Until time T1 when load application occurs, the control unit 72 sets the number of ignitions per cycle to 1 and the discharge energy to setting A, and the ignition device 40 ignites the spark plugs 14a to 14d with this ignition setting. At time T1, the circuit breaker 22 turns on, and the generator 20 is connected to the power system 21 (load application). At this time, the acquisition unit 71 acquires the ON signal (connection) of the circuit breaker 22. Upon acquiring the ON signal of the circuit breaker 22, the control unit 72 immediately sets the number of ignitions per cycle to 2 (multiple times) and the discharge energy to setting B. The ignition device 40 ignites the spark plugs 14a to 14d with this ignition setting. When a load is applied while the generator 20 is operating independently, disconnected from the power grid 21, the rotational speed of the gas engine 10 decreases, and the amount of air supplied to the engine decreases. In response, the control unit 72 increases the number of ignitions and discharge energy triggered by the ON signal from the circuit breaker 22. This ensures ignition stability. After a predetermined time (a predetermined value within 1 minute) has elapsed and it is time T2 (or when the rotational speed of the gas engine 10 reaches a value corresponding to the required power generation output and the rotational speed stabilizes), the control unit 72 returns the number of ignitions per cycle to 1 and the discharge energy to setting A. The ignition device 40 ignites the spark plugs 14a to 14d with this ignition setting (from time T2 onward).

[0091] Figure 13 is a diagram illustrating the ignition control according to Embodiment 8 of the embodiment. Referring to Figure 13, the ignition control during load shedding will be explained. Graph 901 in Figure 13 shows the change in required power output. Graph 902 shows the change in the number of ignitions and discharge energy. Until time T1 when load shedding occurs, the control unit 72 sets the number of ignitions per cycle to 1 and the discharge energy to setting A, and the ignition device 40 ignites the spark plugs 14a to 14d with this ignition setting. At time T1, the circuit breaker 22 turns off, and the generator 20 is disconnected from the power system 21 (load shedding). At this time, the acquisition unit 71 acquires the off signal (shutdown) of the circuit breaker 22. Upon acquiring the off signal of the circuit breaker 22, the control unit 72 immediately sets the number of ignitions per cycle to 2 (multiple times) and the discharge energy to setting B. The ignition device 40 ignites the spark plugs 14a to 14d with this ignition setting. When the generator 20 disconnects from the power grid 21 and switches to independent operation, the rotational speed of the gas engine 10 increases, and the amount of air supplied to the engine increases. In response, the control unit 72 increases the number of ignitions and discharge energy triggered by the off signal from the circuit breaker 22. This ensures ignition stability. After a predetermined time (a predetermined value within 1 minute) has elapsed and it is time T2 (or when the rotational speed of the gas engine 10 reaches a value corresponding to the required power output and the rotational speed stabilizes), the control unit 72 returns the number of ignitions per cycle to 1 and the discharge energy to setting A. The ignition device 40 ignites the spark plugs 14a to 14d with this ignition setting (from time T2 onward).

[0092] (effect) As described above, according to this embodiment, the operating state (output, combustion state), operating conditions (fuel gas properties, load application, load cutoff), and operating environment (ambient temperature, humidity) of the gas engine 10 are understood, and the number of ignitions and discharge energy are set accordingly to control the ignition of the spark plug. This makes it possible to optimize (minimize) the number of ignitions and discharge energy, suppress wear on the electrodes of the spark plug, and extend the lifespan of the spark plug. Furthermore, it is possible to achieve both stable operation and economic efficiency of the gas engine 10.

[0093] Figure 14 is a schematic block diagram showing the hardware configuration of a control device according to an embodiment. The computer 90 includes a processor 91, main memory 92, storage 93, and interface 94. The control device 70 described above is implemented in the computer 90. The operation of each processing unit described above is stored in the storage 93 in the form of a program. The processor 91 reads the program from the storage 93, loads it into the main memory 92, and executes the above processing according to the program. The processor 91 also allocates memory areas in the main memory 92 corresponding to each of the above-mentioned storage units according to the program. Examples of the processor 91 include a CPU (Central Processing Unit), a GPU (Graphic Processing Unit), and a microprocessor.

[0094] The program may be for implementing some of the functions that the computer 90 is to perform. For example, the program may perform functions in combination with other programs already stored in storage, or in combination with other programs implemented in other devices. In other embodiments, the computer 90 may be equipped with a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device) in addition to or instead of the above configuration. Examples of PLDs include PAL (Programmable Array Logic), GAL (Generic Array Logic), CPLD (Complex Programmable Logic Device), and FPGA (Field Programmable Gate Array). In this case, some or all of the functions implemented by the processor 91 may be implemented by the integrated circuit. Such an integrated circuit is also included as an example of a processor.

[0095] Examples of storage 93 include HDDs (Hard Disk Drives), SSDs (Solid State Drives), magnetic disks, magneto-optical disks, CD-ROMs (Compact Disc Read Only Memory), DVD-ROMs (Digital Versatile Disc Read Only Memory), and semiconductor memory. Storage 93 may be an internal medium directly connected to the bus of the computer 90, or an external medium connected to the computer 90 via an interface 94 or a communication line. Furthermore, if this program is distributed to the computer 90 via a communication line, the computer 90 that receives the program may expand it into the main memory 92 and execute the above processing. In at least one embodiment, storage 93 is a tangible storage medium that is not temporary. The program may also be for implementing some of the functions described above. Moreover, the program may be a so-called differential file (differential program) that implements the functions described above in combination with other programs already stored in storage 93.

[0096] As described above, several embodiments relating to this disclosure have been explained, but all of these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents.

[0097] <Note> The control device, control method, and program described in each embodiment can be understood, for example, as follows:

[0098] (1) The control device according to the first embodiment is a control device for a spark plug that ignites the air-fuel mixture in the cylinder of an engine, and comprises a control unit that sets the number of ignitions in one cycle and the discharge energy to be supplied to the spark plug according to the operating state of the engine. This helps to suppress wear on the spark plug electrodes.

[0099] (2) The control device according to the second embodiment is the control device according to (1), wherein the control unit reduces the number of ignitions when the output of the engine is equal to or greater than a first threshold compared to when it is not. This allows for stable ignition and combustion of the fuel-air mixture while suppressing electrode wear.

[0100] (3) The control device according to the third embodiment is the control device described in (1) to (2), wherein the control unit increases the discharge energy when the combustion state of the engine is unstable compared to when it is not. This allows for stabilization of the ignition and combustion of the fuel-air mixture.

[0101] (4) The control device according to the fourth embodiment is the control device described in (3), wherein the control unit increases the number of ignitions if the combustion state of the engine is unstable even when the discharge energy is increased. This allows for stabilization of the ignition and combustion of the fuel-air mixture.

[0102] (5) The control device according to the fifth embodiment is the control device described in (1) to (4), wherein the control unit increases the discharge energy or increases the number of ignitions compared to when the combustion state of the engine remains unstable for a predetermined time. This allows for stabilization of the ignition and combustion of the fuel-air mixture.

[0103] (6) The control device according to the sixth embodiment is the control device described in (1) to (5), wherein the control unit increases the discharge energy or increases the number of ignitions when the temperature of the engine operating environment is below the second threshold or when the humidity is above the third threshold compared to when it is not. This allows for stabilization of the ignition and combustion of the fuel-air mixture.

[0104] (7) The control device according to the seventh embodiment is the control device described in (1) to (6), wherein the control unit increases the discharge energy or increases the number of ignitions when the properties of the engine fuel are outside the standard range compared to when they are not. This allows for stabilization of the ignition and combustion of the fuel-air mixture.

[0105] (8) The control device according to the eighth aspect is the control device described in (1) to (7), wherein when the control unit detects that a load has been applied to or removed from the generator driven by the engine, it increases the number of ignitions and increases the discharge energy. This allows for stable ignition and combustion of the fuel-air mixture, even during load cutoff or load application.

[0106] (9) The control device according to the ninth embodiment is the control device described in (1) to (8), wherein the control unit reduces the number of ignitions when the output of the engine is above a first threshold and the combustion state of the engine is stable, compared to when the output of the engine is above a first threshold and the combustion state of the engine is unstable. This allows for stable ignition and combustion of the fuel-air mixture while suppressing electrode wear.

[0107] (10) A control device according to the tenth embodiment is the control device described in (1) to (8), wherein the control unit sets the number of ignitions to multiple times when the output of the engine is equal to or greater than the first threshold and the combustion state of the engine is unstable, and increases the discharge energy when the spark plug is ignited with the setting and the unstable combustion state continues. This allows for stabilization of the ignition and combustion of the fuel-air mixture.

[0108] (11) A control device according to the 11th embodiment is the control device described in (10), wherein the control unit increases the discharge energy when the combustion state remains unstable as a result of reducing the discharge energy and setting the number of ignitions to multiple times to ignite the spark plug. This allows for stabilization of the ignition and combustion of the fuel-air mixture.

[0109] (12) A control device according to the twelfth embodiment is a control device according to (1) to (8) and (10) to (11), wherein the control unit sets the number of ignitions to multiple times when the output of the engine is less than the first threshold, and increases the discharge energy when the combustion state is unstable as a result of igniting the spark plug with said setting. This allows for stabilization of the ignition and combustion of the fuel-air mixture.

[0110] (13) The control device according to the 13th embodiment is the control device described in (1) to (12), wherein the setting is defined as ignition setting 1, where the number of ignitions is 1 and the discharge energy is a relatively low first discharge energy; ignition setting 2, where the number of ignitions is 1 and the discharge energy is a relatively high second discharge energy; ignition setting 3, where the number of ignitions is multiple and the discharge energy is the first discharge energy; and ignition setting 4, where the number of ignitions is multiple and the discharge energy is the second discharge energy. In this case, the control unit sets ignition setting 1 as the ignition condition when the output of the engine is equal to or greater than a first threshold; sets ignition setting 2 when the combustion state of the engine becomes unstable; sets ignition setting 3 if the combustion state of the engine is still unstable; and sets ignition setting 4 if the combustion state of the engine is still unstable. This allows for stable ignition and combustion of the fuel-air mixture while suppressing electrode wear.

[0111] (14) The control device according to the 14th embodiment is the control device described in (13), wherein the control unit sets the ignition setting 3 as the ignition condition when the output of the engine is less than a first threshold, and sets the ignition setting 4 as the ignition condition when the combustion state of the engine becomes unstable. This allows for stable ignition and combustion of the fuel-air mixture while suppressing electrode wear.

[0112] (15) A control method according to the 15th embodiment, a method for controlling a spark plug that ignites the air-fuel mixture in the cylinder of an engine, wherein a computer sets the number of ignitions in one cycle and the discharge energy to be supplied to the spark plug according to the operating state of the engine.

[0113] (16) The program according to the 16th aspect causes a computer to perform a process for controlling a spark plug that ignites the fuel mixture in the cylinder of an engine, wherein the computer sets the number of ignitions in one cycle and the discharge energy to be supplied to the spark plug according to the operating state of the engine. [Explanation of symbols]

[0114] 10. Gas engine 20... Generators 30. Gas supply controller 40...Ignition device 60. Combustion diagnostic device 70... Control device 71...Acquisition part 72... Control Unit 73...Storage section 80...Fuel management device 1a, 1b, 1c, 1d... Pressure sensors 11. Supercharger 11a, 11b, 11c, 11d... Air system 11a1, 11b1, 11c1, 11d1... Air supply system 12a, 12b, 12c, 12d... cylinders 13a, 13b, 13c, 13d... sub-room 14a, 14b, 14c, 14d... Spark plugs 15a, 15b, 15c, 15d... Fuel gas system for the main chamber 16a, 16b, 16c, 16d... valves 17a, 17b, 17c, 17d...Fuel gas system for sub-chamber 18a, 18b, 18c, 18d... valves 19a, 19b, 19c, 19d... Exhaust system 20... Generators 21...Power system 22... Circuit breaker 23. Output Sensor 24. Temperature sensor 25. Humidity sensor 90... Computer 91... Processor 92···Main Memory 93.. Storage 94. Interface 100... Engine System

Claims

1. A control device for a spark plug that ignites the fuel mixture in the cylinder of an engine, A control unit sets the number of ignitions per cycle and the discharge energy supplied to the spark plug according to the operating state of the engine. Equipped with, The control unit increases the discharge energy when the combustion state of the engine is unstable compared to when it is not, and if the combustion state of the engine remains unstable even after increasing the discharge energy, it increases the number of ignitions. Control device.

2. The control unit reduces the number of ignitions when the engine output is above a first threshold, compared to when it is not. The control device according to claim 1.

3. The control unit increases the discharge energy or the number of ignitions compared to when the engine combustion state remains unstable for a predetermined period of time. The control device according to claim 1 or claim 2.

4. The control unit increases the discharge energy or the number of ignitions when the temperature of the engine's operating environment is below a second threshold, or when the humidity is above a third threshold, compared to when it is not. The control device according to claim 1 or claim 2.

5. The control unit increases the discharge energy or the number of ignitions when the properties of the engine fuel are outside the standard range, compared to when they are not. The control device according to claim 1 or claim 2.

6. When the control unit detects that a load has been applied to or removed from the generator driven by the engine, it increases the number of ignitions and increases the discharge energy. The control device according to claim 1 or claim 2.

7. The control unit reduces the number of ignitions when the engine output is above a first threshold and the engine combustion state is stable, compared to when the engine output is above a first threshold and the engine combustion state is unstable. The control device according to claim 1.

8. A control device for a spark plug that ignites the fuel mixture in the cylinder of an engine, A control unit sets the number of ignitions per cycle and the discharge energy supplied to the spark plug according to the operating state of the engine. Equipped with, The control unit increases the discharge energy when the engine output is above a first threshold and the engine combustion state is unstable, and if the combustion state remains unstable as a result of ignition at the spark plug with this setting, it decreases the discharge energy and sets the number of ignitions to multiple times. Control device.

9. The control unit reduces the discharge energy and sets the number of ignitions to multiple times to ignite the spark plug, and if the combustion state remains unstable as a result, it increases the discharge energy. The control device according to claim 8.

10. A control device for a spark plug that ignites the fuel mixture in the cylinder of an engine, A control unit sets the number of ignitions per cycle and the discharge energy supplied to the spark plug according to the operating state of the engine. Equipped with, The control unit, when the engine output is below a first threshold, sets the number of ignitions to multiple times, and if the combustion state of the engine is unstable as a result of igniting the spark plug with this setting, increases the discharge energy. Control device.

11. A control device for a spark plug that ignites the fuel mixture in the cylinder of an engine, A control unit sets the number of ignitions per cycle and the discharge energy supplied to the spark plug according to the operating state of the engine. Equipped with, Ignition setting 1 is defined as a setting where the number of ignitions is 1 and the discharge energy is a relatively low first discharge energy. Ignition setting 2 is defined as a setting where the number of ignitions is 1 and the discharge energy is a second discharge energy which is relatively high. Ignition setting 3 is a setting in which the number of ignitions is multiple and the discharge energy is set to the first discharge energy. When the number of ignitions is multiple, and the setting for the discharge energy is the second discharge energy, the ignition setting 4 is selected. The control unit sets ignition setting 1 as the ignition condition when the engine output is equal to or greater than a first threshold, sets ignition setting 2 when the combustion state of the engine becomes unstable, sets ignition setting 3 when the combustion state of the engine is still unstable, and sets ignition setting 4 when the combustion state of the engine is still unstable. Control device.

12. The control unit sets ignition setting 3 as the ignition condition when the engine output is below a first threshold, and sets ignition setting 4 as the ignition condition when the engine combustion state becomes unstable. The control device according to claim 11.

13. A method for controlling a spark plug that ignites the fuel-air mixture in an engine cylinder, The computer has a step of setting the number of ignitions per cycle and the discharge energy to be supplied to the spark plug, according to the operating state of the engine. In the setting step, if the combustion state of the engine is unstable, the discharge energy is increased compared to when it is not unstable, and if the combustion state of the engine remains unstable even after increasing the discharge energy, the number of ignitions is increased. Control method.

14. On the computer, A process that controls the spark plug that ignites the fuel mixture in the cylinder of an engine, The system includes a step of setting the number of ignitions per cycle and the discharge energy supplied to the spark plug, according to the operating state of the engine. In the setting step, if the combustion state of the engine is unstable, the discharge energy is increased compared to when it is not unstable, and if the combustion state of the engine is still unstable even after increasing the discharge energy, the number of ignition cycles is increased. A program that executes the command.

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