JP7409785B2 - Gas engine control device, gas engine system, and gas engine control program - Google Patents

Description

The present disclosure relates to a gas engine control device, a gas engine system, and a gas engine control program.

BACKGROUND ART As a gas engine that uses gas such as city gas as its main fuel, a sub-chamber type gas engine that includes a main chamber and a sub-chamber as a combustion chamber is used.

Patent Document 1 describes a sub-chamber type gas engine that includes a main chamber defined by a cylinder and a piston, and a sub-chamber that communicates with the main chamber via a nozzle.
Generally, in such a gas engine, during the intake stroke, a relatively lean air-fuel mixture is supplied to the main chamber via the air supply pipe, and fuel gas is supplied to the subchamber via the subchamber gas supply pipe. be done. During the compression stroke, an air-fuel mixture at a near stoichiometric air-fuel ratio is formed in the pre-chamber, and the air-fuel mixture in the pre-chamber is ignited by a spark plug provided in the pre-chamber. Then, during the expansion stroke, the flame generated in the sub-chamber is ejected into the main chamber through the nozzle, the flame propagates into the air-fuel mixture in the main chamber, and the fuel gas in the main chamber is combusted.

Furthermore, Patent Document 1 discloses that the sub-chamber gas supply pipe is controlled based on the pressure difference between the pressure in the sub-chamber gas supply pipe and the pressure in the air supply pipe that supplies the air-fuel mixture to the main chamber, that is, the sub-chamber pressure difference. The amount of fuel gas supplied to the auxiliary chamber through the auxiliary chamber is adjusted.

Patent No. 4418124

By the way, in pre-chamber gas engines, depending on how the amount of fuel gas supplied to the pre-chamber is controlled, the engine speed may drop significantly when a load is applied, and it may take some time for engine operation to stabilize. . In other words, when the amount of air-fuel mixture supplied to the main chamber is increased when a load is applied, the excess air ratio in the main chamber decreases rapidly, and the excess air ratio may drop to about 1 (that is, about the stoichiometric air-fuel ratio). be. At this time, for example, if control is carried out based on the pre-chamber differential pressure as described in Patent Document 1, the excess air ratio in the pre-chamber at the time of ignition will also drop rapidly as the excess air ratio in the main chamber decreases. . Therefore, at the time of ignition, the air-fuel mixture concentration in the subchamber becomes excessively high, which may cause a misfire in the subchamber. When a misfire occurs in the pre-chamber, the engine speed drops significantly, and it takes time for the engine speed to recover and stabilize.

In view of the above circumstances, it is an object of at least one embodiment of the present invention to provide a gas engine control device, a gas engine system, and a gas engine control program that can operate stably even when a load is applied. shall be.

(1) A gas engine control device according to at least one embodiment of the present invention includes:
A main chamber defined by a cylinder and a piston, a sub-chamber having a nozzle and communicating with the main chamber via the nozzle, and a sub-chamber for adjusting the amount of fuel gas supplied to the sub-chamber. A gas engine control device including a gas regulating valve,
At least when the engine load increases, the main chamber excess air ratio λ1 is the excess air ratio of the air-fuel mixture supplied to the main chamber, and the pre-chamber excess air ratio λ2 is the excess air ratio of the gas in the auxiliary chamber at the time of ignition. , and based on a misfire rate map showing the correlation between the misfire rates, an opening command value of the pre-chamber gas regulating valve is determined so that the pre-chamber excess air ratio λ2 does not fall into the misfire region in the misfire rate map. A command value setting section configured to set the command value is provided.

In the configuration (1) above, at least when the engine load increases (for example, when applying a load), the misfire rate map showing the correlation between the main chamber excess air ratio λ1, the pre-chamber excess air ratio λ2, and the misfire rate is created. Based on this, the opening command value of the pre-chamber gas adjustment valve is set so that the pre-chamber excess air ratio λ2 does not fall into the misfire region of the misfire rate map (for example, the opening command value is reduced to below a specified value). etc). Therefore, even if the main chamber excess air ratio λ1 is relatively small, the amount of fuel gas supplied to the auxiliary chamber can be appropriately adjusted to prevent the auxiliary chamber excess air ratio λ2 from becoming excessively small. Misfires in the subchamber can be avoided. As a result, it is possible to suppress a significant decrease in the engine speed when a load is applied, and the engine can be operated stably even when a load is applied.
Note that the misfire regions of the misfire rate map are regions of λ1 and λ2 where the misfire rate is high and misfires are likely to occur.

(2) In some embodiments, in the configuration of (1) above,
The control device includes:
At least the pressure P1 of the air-fuel mixture supplied to the main chamber, the main chamber excess air ratio λ1, and the difference between the pressure P2 of the fuel gas supplied to the auxiliary chamber and the pressure P1 in the auxiliary chamber. The apparatus includes a pre-chamber excess air ratio calculating section configured to estimate the pre-chamber excess air ratio λ2 based on the differential pressure (P2-P1).

According to the configuration (2) above, at least the pressure P1 of the air-fuel mixture supplied to the main chamber, the main chamber excess air ratio λ1, and the difference between the pressure P2 and the pressure P1 of the fuel gas supplied to the auxiliary chamber. The pre-chamber excess air ratio λ2 can be appropriately estimated based on the pre-chamber differential pressure (P2-P1). Therefore, using the estimated value of the pre-chamber excess air ratio λ2 obtained in this way, and based on the above-mentioned misfire rate map, the pre-chamber excess air ratio λ2 is adjusted so that the pre-chamber excess air ratio λ2 does not fall into the misfire region of the misfire rate map. By setting the opening degree command value of the gas regulating valve, the amount of fuel gas supplied into the subchamber can be appropriately adjusted.

(3) In some embodiments, in the configuration of (2) above,
The gas engine includes a plurality of main chambers each defined by a plurality of cylinders and a piston, and a plurality of auxiliary chambers and a plurality of auxiliary chamber gas adjustment valves respectively provided corresponding to the plurality of main chambers,
The auxiliary chamber excess air ratio calculation unit is configured to estimate the auxiliary chamber excess air ratio λ2 for each of the plurality of cylinders based on a flow coefficient for each of the plurality of cylinders.

When a gas engine includes multiple cylinders and pistons, the nozzle diameter of the subchamber varies from cylinder to cylinder, so even if the above-mentioned subchamber differential pressure (P2-P1) is the same, there is The flow rate of the inflowing air-fuel mixture may vary from cylinder to cylinder (that is, the flow coefficient may differ from cylinder to cylinder).
In this regard, according to configuration (3) above, the pre-chamber excess air ratio λ2 for each of a plurality of cylinders is calculated by taking into account the flow coefficient for each cylinder, so that the pre-chamber excess air ratio λ2 is calculated in this way. By using the estimated value of the pre-chamber excess air ratio λ2, it is possible to more accurately grasp the misfire rate corresponding to the pre-chamber excess air ratio λ2. Therefore, by setting the opening command value of the pre-chamber gas regulating valve for each of the plurality of cylinders so that the estimated value of the obtained pre-chamber excess air ratio λ2 does not fall within the misfire region of the misfire rate map, The amount of fuel gas supplied into the room can be adjusted more appropriately.

(4) In some embodiments, in any of the configurations (1) to (3) above,
The command value setting unit obtains a target sub-chamber excess air ratio λ2* at which the misfire rate is minimal with respect to the current main-chamber excess air ratio λ1, based on the misfire rate map, at least when the engine load increases. The sub-chamber differential pressure (P2-P1), which is the difference between the pressure P2 of the fuel gas supplied to the sub-chamber and the pressure P1 of the air-fuel mixture supplied to the main chamber, is the target sub-chamber pressure. The opening command value of the subchamber gas regulating valve is configured to be set to a target subchamber differential pressure corresponding to the excess air ratio λ2*.

According to the configuration (4) above, based on the misfire rate map, the target pre-chamber excess air rate λ2* at which the dental rate is minimized is obtained corresponding to the current main vaginal excess air rate λ1, and the pre-chamber The opening degree command value of the subchamber gas regulating valve is set so that the pressure becomes the target subchamber differential pressure corresponding to the target subchamber excess air ratio λ2*. Therefore, by adjusting the amount of fuel gas supplied to the auxiliary chamber based on the opening command value set in this way, even if the main chamber excess air ratio λ1 is relatively small, the auxiliary chamber excess air ratio can be adjusted. By suppressing λ2 from becoming excessively small, it is possible to appropriately avoid a misfire in the subchamber.

(5) In some embodiments, in any of the configurations (1) to (4) above,
The gas engine control device is
comprising a map acquisition unit that acquires the misfire rate map according to operating conditions of the gas engine,
The command value setting section is configured to set the opening command value using the misfire rate map acquired by the map acquisition section.

According to the configuration (5) above, the opening command value is set using the misfire rate map according to the engine operating conditions, so it is based on the main chamber excess air ratio λ1 and the pre-chamber excess air ratio λ2. Therefore, it is possible to obtain the misfire rate according to the engine operating conditions. Therefore, based on the misfire rate obtained in this way, the opening degree command value of the pre-chamber gas regulating valve can be set more appropriately. Therefore, even if the main chamber excess air ratio λ1 is relatively small, the amount of fuel gas supplied to the auxiliary chamber can be adjusted more appropriately to prevent the auxiliary chamber excess air ratio λ2 from becoming excessively small. misfire in the subchamber can be avoided.

(6) In some embodiments, in the configuration of (5) above,
The operating conditions include at least one of the outside temperature, the temperature of the air-fuel mixture supplied to the main chamber, and the properties of the fuel gas.

The relationship between the main chamber excess air ratio λ1, the pre-chamber excess air ratio λ2, and the misfire rate may vary depending on the engine operating conditions such as the outside temperature, the temperature of the air-fuel mixture supplied to the main chamber, or the properties of the fuel gas. There is. In this regard, according to the configuration (6) above, since the opening command value is set using the misfire rate map according to these operating conditions, the main chamber excess air ratio λ1 and the auxiliary chamber excess air ratio Based on λ2, it is possible to obtain the misfire rate according to the operating conditions of these engines. Therefore, based on the misfire rate obtained in this way, the opening degree command value of the pre-chamber gas regulating valve can be set more appropriately.

(7) The gas engine system according to at least one embodiment of the present invention includes:
a main chamber defined by a cylinder and a piston;
a sub-chamber having a spout and communicating with the main chamber via the spout;
a gas engine including a subchamber gas adjustment valve for adjusting the amount of fuel gas supplied to the subchamber;
The control device according to any one of (1) to (6) above for controlling the gas engine;
Equipped with.

In the configuration (7) above, at least when the engine load increases (for example, when applying a load), the misfire rate map is based on the misfire rate map showing the correlation between the main chamber excess air ratio λ1, the pre-chamber excess air ratio λ2, and the misfire rate. Then, the opening command value of the pre-chamber gas adjustment valve is set so that the pre-chamber excess air ratio λ2 does not fall into the misfire region of the misfire rate map (for example, by reducing the opening command value below a specified value, etc.) ). Therefore, even if the main chamber excess air ratio λ1 is relatively small, the amount of fuel gas supplied to the auxiliary chamber can be appropriately adjusted to prevent the auxiliary chamber excess air ratio λ2 from becoming excessively small. Misfires in the subchamber can be avoided. As a result, it is possible to suppress a significant decrease in the engine speed when a load is applied, and the engine can be operated stably even when a load is applied.

(8) A gas engine control program according to at least one embodiment of the present invention includes:
A main chamber defined by a cylinder and a piston, a sub-chamber having a nozzle and communicating with the main chamber via the nozzle, and a sub-chamber for adjusting the amount of fuel gas supplied to the sub-chamber. A program for controlling a gas engine including a gas regulating valve,
At least when the engine load increases, the main chamber excess air ratio λ1 is the excess air ratio of the air-fuel mixture supplied to the main chamber, and the pre-chamber excess air ratio λ2 is the excess air ratio of the gas in the auxiliary chamber at the time of ignition. , and based on a misfire rate map showing the correlation between the misfire rates, an opening command value of the pre-chamber gas regulating valve is determined so that the pre-chamber excess air ratio λ2 does not fall into the misfire region in the misfire rate map. This is a program that causes a computer to execute the steps for setting the .

According to the program (8) above, at least when the engine load increases (for example, when applying a load), the misfire rate map shows the correlation between the main chamber excess air ratio λ1, the pre-chamber excess air ratio λ2, and the misfire rate. Based on this, the opening command value of the pre-chamber gas adjustment valve is set so that the pre-chamber excess air ratio λ2 does not fall into the misfire region of the misfire rate map (for example, the opening command value is set to be smaller than the specified value). etc.). Therefore, even if the main chamber excess air ratio λ1 is relatively small, the amount of fuel gas supplied to the auxiliary chamber can be appropriately adjusted to prevent the auxiliary chamber excess air ratio λ2 from becoming excessively small. Misfires in the subchamber can be avoided. As a result, it is possible to suppress a significant decrease in the engine speed when a load is applied, and the engine can be operated stably even when a load is applied.

According to at least one embodiment of the present invention, a gas engine control device, a gas engine system, and a gas engine control program that can operate stably even when a load is applied are provided.

1 is a schematic diagram of a gas engine system according to one embodiment. 1 is a schematic diagram showing a structure around a combustion chamber of a gas engine system according to an embodiment. FIG. 2 is a block diagram of a control device according to an embodiment. 4 is an example of a misfire rate map according to an embodiment. It is a figure showing the calculation flow of the subchamber excess air ratio concerning one embodiment. FIG. 2 is a block diagram of a control device according to an embodiment. 4 is an example of a misfire rate map according to an embodiment.

Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as the embodiments or shown in the drawings are not intended to limit the scope of the present invention thereto, and are merely illustrative examples. do not have.

First, with reference to FIGS. 1 and 2, a gas engine and a gas engine system to which control devices according to some embodiments are applied will be described. FIG. 1 is a schematic diagram of a gas engine system according to one embodiment. FIG. 2 shows a structure around a combustion chamber of a gas engine system according to an embodiment.
Note that in the embodiment described below, the gas engine of the gas engine system is a gas engine with a supercharger for driving a generator. However, the present invention is not limited to the specific configuration of the gas engine of the embodiment described below, and various configurations can be adopted. For example, the driving target may be any driven device other than a generator. There may be.

A gas engine system 1 shown in FIG. 1 includes a gas engine 3 and a control device 5 for controlling the operation of the gas engine 3. The gas engine system 1 also includes an air supply line 103 that supplies a mixed gas of fuel gas such as natural gas or city gas and combustion air to the main chamber 307 of the gas engine 3, and A subchamber gas supply line 105 that supplies the subchamber 315 of the engine 3 is provided.

More specifically, the gas engine system 1 includes a fuel gas supply line 101 connected to the gas mixer 19 to supply fuel gas to the gas mixer 19, and a combustion air line 101 connected to the gas mixer 19 to supply combustion air to the gas mixer 19. A supply line 107 is provided. The fuel gas supply line 101 is provided with a fuel gas supply amount control section 71 that controls the flow rate of the fuel gas supplied to the gas mixer 19 .

Further, the combustion air supply line 107 may be provided with an air cleaner 17 that removes dirt, dust, etc. contained in the combustion air supplied to the gas mixer 19. The gas mixer 19 mixes the fuel gas supplied via the fuel gas supply line 101 and the combustion air supplied via the combustion air supply line 107 to generate a mixed gas.

The gas engine system 1 also includes a supercharger 11 including a compressor 11a and an exhaust turbine 11b, and the above-mentioned air supply line 103. The compressor 11a boosts the pressure of the mixed gas generated by the gas mixer 19, and supplies the boosted mixed gas to the air supply line 103 on the downstream side of the compressor 11a. The exhaust turbine 11b is rotated by exhaust gas discharged from the gas engine 3, and drives the compressor 11a.

The air supply line 103 includes an upstream air supply line 103a disposed on the upstream side in the flow direction of the mixed gas, and an air supply manifold 103b disposed on the downstream side. The upstream air supply line 103a is provided with an air supply control valve 73 that controls the flow rate of the mixed gas supplied to the air supply manifold 103b. This air supply control valve 73 can be, for example, a governor throttle valve. Furthermore, the air supply manifold 103b is provided with an air supply pressure sensor 92 that detects the pressure inside the air supply manifold 103b.

The gas engine system 1 also includes the above-mentioned auxiliary chamber gas supply line 105 that branches from the fuel gas supply line 101 and supplies a portion of the fuel gas to the auxiliary chamber 315 of the gas engine 3 . The subchamber gas supply line 105 is provided with a subchamber gas adjustment valve 75 that controls the flow rate of fuel gas supplied to the subchamber of the gas engine 3 . Further, a sub-chamber gas pressure sensor 94 is provided downstream of the sub-chamber gas supply line 105 in the flow direction of the fuel gas to detect the pressure of the sub-chamber gas supply line 105 .

A crankshaft 4 of the gas engine 3 is equipped with a flywheel 13, and a generator 15 is directly attached to the flywheel 13. The flywheel 13 is provided with a rotation speed sensor 95 that detects the rotation speed of the gas engine 3, and the generator 15 is provided with a load sensor 93 that detects the load of the generator 15, that is, the engine load. Further, the gas engine 3 may be provided with an in-cylinder pressure sensor (not shown) that detects the pressure within the main chamber 307 of the gas engine 3.

As shown in FIG. 2, the gas engine 3 includes a cylinder 301 and a piston 303 fitted in the cylinder 301 so as to be slidable back and forth. A main chamber (main combustion chamber) 307 is defined by the upper surface of the piston 303 and the inner surfaces of the cylinder 301 and cylinder liner 305.

The gas engine 3 also includes an intake port 311 connected to the main chamber 307, an intake valve 313 that opens and closes the intake port 311, and the like. The above-mentioned air supply line 103 is connected to the upstream side of the intake port 311. Therefore, the mixed gas supplied via the air supply line 103 reaches the intake valve 313 via the intake port 311, and is supplied to the main chamber 307 when the intake valve 313 is opened.

The gas engine 3 includes a nozzle holder 321 and a sub-chamber cap 317 attached to the tip of the nozzle holder 321, and a region surrounded by the lower end surface of the nozzle holder 321 and the inner surface of the sub-chamber cap 317 A subchamber 315 is formed. A plurality of nozzles 319 are formed in the sub-chamber mouthpiece 317 to communicate the main chamber 307 and the sub-chamber 315.

Inside the nozzle holder 321, a subchamber gas line 323 connected to the subchamber gas supply line 105 described above, and an ignition device 325 for igniting the fuel gas supplied by the subchamber gas line 323 in the subchamber 315 are provided. is provided.

Further, the subchamber gas line 323 is provided with a check valve 327 . The amount of fuel gas supplied to the subchamber 315 via the check valve 327 is the difference between the pressure on the upstream side of the check valve 327 in the subchamber gas supply line 105 and the pressure on the downstream side of the check valve 327. Determined by the differential pressure in the subchamber. Here, the pressure on the downstream side of the check valve 327 can be determined based on, for example, the pressure in the auxiliary chamber 315, the pressure in the main chamber 307, or the pressure in the air supply line 103.
By adjusting the sub-chamber differential pressure with the sub-chamber gas adjustment valve 75, the flow rate of fuel gas supplied to the sub-chamber 315 via the check valve 327 can be controlled. Note that, as will be described in detail later, the opening degree of the subchamber gas regulating valve 75 is controlled by the control device 5.

As shown in FIG. 1, the control device 5 includes a command value setting section 20. The command value setting section 20 includes a first command value calculation section 24 (described later), a main chamber excess air ratio calculation section 26, an auxiliary chamber excess air ratio calculation section 28, a misfire rate acquisition section 30, a storage section 34, and an auxiliary chamber excess air ratio. It includes a target value setting section 43 and the like.

The control device 5 may include a CPU, a memory (RAM), an auxiliary storage device, an interface, and the like. The control device 5 is configured to receive information (signals indicating measurement results) from various sensors (supply air pressure sensor 92, pre-chamber gas pressure sensor 94, load sensor 93, rotation speed sensor 95, etc.) via an interface. has been done. The CPU is configured to process the information received in this manner. Further, the CPU is configured to process a program developed in memory.

The above-mentioned command value setting section 20 and the like may be implemented as a program executed by the CPU and stored in the auxiliary storage device. When programs are executed, these programs are expanded into memory. The CPU reads the program from the memory and uses information received from various sensors as necessary to execute instructions included in the program.

Hereinafter, the control device 5 according to some embodiments will be described in more detail.

The command value setting unit 20 of the control device 5 uses signals received from various sensors (supply air pressure sensor 92, pre-chamber gas pressure sensor 94, load sensor 93, rotation speed sensor 95, etc.) and a misfire rate map described later. Accordingly, the opening command value of the subchamber gas regulating valve 75 is calculated (set). The subchamber gas adjustment valve 75 is configured to receive an opening degree command value from the control device 5 and adjust its opening degree based on the opening degree command value.

3 and 6 are block diagrams of the control device 5 according to one embodiment, respectively. Control based on the control flows shown in FIGS. 3 and 6 is performed at least when the load on the gas engine 3 increases. The time when the engine load increases refers to a time when the engine load is in a transient operating state, which is different from the steady state of operation, and for example, the load on the generator 15 (see FIG. 1) connected to the gas engine 3. Including the time of input, etc. Note that the control according to the control flow shown in FIG. 3 may be performed during steady operation of the gas engine 3 (that is, when the engine load is in an operating state where the engine load changes almost steadily).

In the exemplary embodiment shown in FIG. 3, the command value setting section 20 includes a first command value calculation section (feedback command value calculation section) 24, a main chamber excess air ratio calculation section 26, and an auxiliary chamber excess air ratio calculation section 28. , a misfire rate acquisition section 30, a comparison section 36, a switching device 40, and the like.

In the control device 5 shown in FIG. 3, the first command value calculation unit 24 calculates a feedback command value _IFB that is a candidate for the opening command value I of the subchamber gas regulating valve 75. Specifically, first, the target value of the pre-chamber differential pressure and the actual pre-chamber differential pressure (P2-P1) are input to the subtracter 22, and the subtracter 22 converts the actual pre-chamber differential pressure and the above-mentioned The deviation (difference) from the target value is calculated.

Here, the pre-chamber pressure difference is the difference between the pressure P2 of the fuel gas supplied to the sub-chamber 315 (see FIG. 2) of the gas engine 3 and the pressure P1 of the air-fuel mixture supplied to the main chamber 307. .
The target value of the pre-chamber differential pressure is obtained from a map of the pre-chamber differential pressure with respect to engine speed and engine load. Note that the above-mentioned map obtained in advance through experiments or the like is stored in the storage device of the control device 5, and the map is read from the storage device when the first command value calculation unit 24 performs calculations. Good too.
Further, the actual subchamber pressure difference (P2-P1) may be calculated based on the pressure P2 acquired by the subchamber gas pressure sensor 94 and the pressure P1 acquired by the supply air pressure sensor 92.

The deviation between the actual value of the pre-chamber differential pressure calculated by the subtracter 22 and the target value is inputted to the first command value calculation unit 24. The first command value calculation unit 24 calculates a feedback command value _IFB related to the opening degree of the subchamber gas adjustment valve 75 based on the deviation, and outputs it to the switching device 40.

Note that the first command value calculation unit 24 may be a PI controller that calculates and outputs the feedback command value _IFB by performing proportional/integral calculations based on the deviation received from the subtractor 22. Alternatively, the first command value calculation unit 24 may be a PID controller that calculates and outputs the feedback command value _IFB by performing proportional, integral, and differential operations based on the deviation received from the subtracter 22. .

On the other hand, in the control device 5 shown in FIG. The excess rate calculation unit 28 calculates the subchamber excess air rate λ2, which is the excess air rate of the gas in the subchamber 315 at the time of ignition.

The main chamber excess air ratio λ1 can be calculated from the amount of air supplied to the main chamber 307 via the air supply manifold 103b and the amount of fuel. The amount of air supplied to the main chamber 307 can be calculated using, for example, the engine speed, the air supply line pressure, and a volumetric efficiency map. Further, the amount of fuel supplied to the main chamber 307 can be calculated based on, for example, the flow rate in the fuel gas supply amount control section 71 provided in the fuel gas supply line 101.
The main chamber excess air ratio λ1 calculated by the main chamber excess air ratio calculation section 26 is output to the misfire rate acquisition section 30 and the sub-chamber excess air ratio calculation section 28.

The auxiliary chamber excess air ratio λ2 is at least the pressure P1 of the air-fuel mixture supplied to the main chamber 307, the main chamber excess air ratio λ1 calculated by the main chamber excess air ratio calculation unit 26, and the air mixture supplied to the auxiliary chamber 315. It is calculated and estimated based on the pre-chamber pressure difference (P2-P1), which is the difference between the pressure P2 and the pressure P1 of the fuel gas.

Here, with reference to FIG. 5, the method of calculating the subchamber excess air ratio λ2 will be explained in more detail. FIG. 5 is a diagram showing a calculation flow of the subchamber excess air ratio λ2 according to one embodiment.

As shown in FIG. 5, first, the subchamber pressure difference is measured (calculated) (step S1). Next, the amount of fuel gas supplied to the auxiliary chamber 315 is calculated (step S2). Next, the amount of air and fuel gas in the auxiliary chamber 315 before ignition are calculated (step S4). Next, the amount of air and fuel gas in the subchamber 315 at the ignition timing are calculated (step S6). Then, the excess air ratio λ2 in the subchamber 315 at the ignition timing is calculated (step S8).
Note that before ignition is the time when the piston 303 is located near the bottom dead center and the volume of the main chamber is the largest, and ignition timing is the time when the piston 303 is located near the top dead center and the volume of the main chamber is the largest. This is the smallest period.

In step S1, the pressure P2 of the fuel gas supplied to the auxiliary chamber 315 is measured by the auxiliary chamber gas pressure sensor 94, and the pressure P1 of the air-fuel mixture supplied to the main chamber 307 is measured by the supply air pressure sensor 92. . Then, the subchamber pressure difference (P2-P1) is calculated based on the measurement results of the pressures P1 and P2.

In step S2, the amount of fuel gas supplied to the subchamber 315 is calculated based on the subchamber differential pressure (P2-P1) described above.
In step S4, the amount of air and fuel gas in the subchamber 315 before ignition are calculated based on the amount of fuel gas supplied to the subchamber 315 and the volume of the subchamber 315 calculated in step S2.
In step S6, based on the air amount and fuel gas amount in the auxiliary chamber 315 before ignition calculated in step S4, the main chamber excess air ratio λ1 calculated by the main chamber excess air ratio calculation unit 26, the compression ratio, etc. Then, the amount of air and fuel gas in the subchamber 315 at the ignition timing are calculated.
In step S8, the excess air ratio λ2 of the gas in the subchamber 315 at the time of ignition is calculated based on the air amount and fuel gas amount in the subchamber 315 at the ignition timing calculated in step S6.

As shown in FIG. 3, the subchamber excess air ratio λ2 calculated by the subchamber excess air ratio calculation unit 28 is output to the misfire rate acquisition unit 30.

The misfire rate acquisition unit 30 determines the main chamber excess air ratio λ1 and the sub-chamber excess air ratio λ2 that have been input, based on the main chamber excess air ratio λ1 and the sub-chamber excess air ratio λ2, and the misfire rate map 200 acquired from the storage unit 34. A misfire rate R corresponding to the rate λ2 is obtained.

FIG. 4 is an example of a misfire rate map 200. The misfire rate map 200 is a map showing the correlation between the main chamber excess air ratio λ1, the sub-chamber excess air ratio λ2, and the misfire rate R. In FIG. 4, the vertical axis shows the main chamber excess air ratio λ1, and the horizontal axis shows the sub-chamber excess air ratio λ2.

Further, in FIG. 4, straight lines L11 to L13 and L21 to L23 each represent a constant misfire rate curve (note that in FIG. 4, the constant misfire rate curve is a straight line). R1 to R3 in the figure indicate that the misfire rate on straight lines L11 and L21 is R1, the misfire rate on straight lines L12 and L22 is R2, and the misfire rate on straight lines L13 and L23 is R3.
The magnitude relationship between the misfire rates R1 to R3 is R1<R2<R3. That is, in the region A1 on the left side of the straight line L11 (region where λ2 is small), the misfire rate increases as λ2 becomes smaller. Furthermore, in the region A2 on the right side of the straight line L21 (region where λ2 is large), the misfire rate increases as λ2 increases.

In the misfire rate map 200 shown in FIG. 4, areas A1 and A2 in which the misfire rate is higher than R1 indicate misfire areas where a misfire in the pre-chamber is likely to occur. Note that in the misfire rate map 200, the area A0 where the misfire rate is smaller than R1 is a stable combustion area where the possibility of misfire occurring in the pre-chamber is relatively low.

That is, if the main chamber excess air ratio λ1 and the sub-chamber excess air ratio λ2 have been acquired, by referring to the misfire rate map 200, the misfire rate corresponding to the main chamber excess air ratio λ1 and the sub-chamber excess air ratio λ2 is determined. It is possible to obtain R.

The misfire rate map 200 may be created experimentally in advance. Further, a misfire rate map 200 created in advance may be stored in the storage unit 34 of the control device 5.

The misfire rate R acquired by the misfire rate acquisition section 30 is input to the comparison section 36. The comparison unit 36 compares the input misfire rate R with a threshold value Rth. The threshold value Rth may be, for example, R1 in the misfire rate map 200 shown in FIG. 4. When the misfire rate R is larger than R1, this is because the misfire rate R is within the misfire areas A1 and A2.

As a result of comparing the misfire rate R and the threshold value Rth in the comparison unit 36, if the misfire rate R is larger than the threshold value Rth (R>Rth), the comparison unit 36 outputs a signal indicating “ON”, and this signal is The receiving switch 40 reads the opening command value Imem (fixed value) from the memory 38 and outputs it as the opening command value I to the subchamber gas regulating valve 75 . The opening command value Imem may be zero, for example. In this case, a zero value is output as the opening degree command value I, and the subchamber gas regulating valve 75 is closed (that is, the opening degree becomes zero).

On the other hand, as a result of comparing the misfire rate R and the threshold value Rth in the comparison unit 36, if the misfire rate R is smaller than the threshold value Rth (R<Rth), the comparison unit 36 outputs a signal indicating “OFF”, and this The switching device 40 that has received the signal outputs the feedback command value _IFB received from the first command value calculation unit 24 as the opening command value I to the subchamber gas adjustment valve 75. In this case, the opening degree of the subchamber gas adjustment valve 75 is adjusted to match the feedback command value _IFB .

The command value setting unit 20 of the control device 5 according to the embodiment described above determines, based on the misfire rate map 200 described above, that the pre-chamber excess air ratio λ2 corresponds to the misfire in the misfire rate map 200 at least when the engine load increases. The opening command value I of the pre-chamber gas regulating valve 75 is set so as not to fall within the ranges A1 and A2 (see FIG. 4).
That is, when the misfire rate R obtained from the misfire rate map 200 exceeds the threshold value Rth and is about to enter the misfire regions A1, A2, the opening command value I of the pre-chamber gas regulating valve 75 is set to a specified value (for example, zero). It is supposed to be.

Therefore, even if the main chamber excess air ratio λ1 is relatively small, the amount of fuel gas supplied into the subchamber 315 is appropriately adjusted to prevent the subchamber excess air ratio λ2 from becoming excessively small. This allows you to avoid misfires in the subchamber. As a result, it is possible to suppress a significant decrease in the engine speed when a load is applied, and the engine can be operated stably even when a load is applied.

In the embodiment described above, the auxiliary chamber excess air ratio calculation unit 28 of the control device 5 calculates at least the pressure P1 of the air-fuel mixture supplied to the main chamber 307, the main chamber excess air ratio λ1, and the auxiliary chamber 315. It is configured to estimate the subchamber excess air ratio λ2 based on the subchamber differential pressure (P2-P1), which is the difference between the pressure P2 of the supplied fuel gas and the pressure P1.

According to the sub-chamber excess air ratio calculating section 28 having the above-described configuration, the sub-chamber excess air ratio λ2 can be appropriately estimated. Therefore, using the estimated value of the pre-chamber excess air ratio λ2 obtained in this way, it is possible to determine whether the pre-chamber excess air ratio λ2 falls within the misfire regions A1, A2 of the misfire rate map 200 based on the misfire rate map 200 described above. By setting the opening degree command value I of the sub-chamber gas adjustment valve 75 such that the amount of fuel gas supplied into the sub-chamber 315 is not exceeded, it is possible to appropriately adjust the amount of fuel gas supplied into the sub-chamber 315.

Further, the command value setting unit 20 determines that, at least when the engine load increases, the misfire rate R obtained from the misfire rate map 200 based on the main chamber excess air ratio λ1 and the subchamber excess air ratio λ2 is larger than the threshold value Rth. The opening command value I of the pre-chamber gas regulating valve 75 may be set to zero when the pre-chamber gas adjustment valve 75 reaches zero.

In this case, when the misfire rate R obtained from the misfire rate map 200 based on the main chamber excess air ratio λ1 and the sub-chamber excess air ratio λ2 becomes larger than the threshold Rth value, the pre-chamber gas regulating valve 75 is opened. The temperature command value I is set to zero, and the supply of fuel gas to the auxiliary chamber 315 is cut off. Therefore, even if the main chamber excess air ratio λ1 is relatively small, by cutting off the supply of fuel gas into the auxiliary chamber 315, the auxiliary chamber excess air ratio λ2 can be prevented from becoming excessively small. Misfires in the subchamber can be more reliably avoided. As a result, it is possible to suppress a significant decrease in the engine speed when a load is applied, and the engine can be operated stably even when a load is applied.

Furthermore, in the embodiment described above, the first command value calculation unit (feedback command value calculation unit) 24 calculates It is configured to calculate a feedback command value _IFB for the opening degree of the subchamber gas regulating valve 75. Then, at least when the engine load increases, the command value setting unit 20 determines that the misfire rate R obtained from the misfire rate map 200 based on the main chamber excess air ratio λ1 and the subchamber excess air ratio λ2 is equal to or lower than the threshold value Rth. In some cases, the feedback command value _IFB is set as the opening command value I to be output to the subchamber gas regulating valve 75.

In this manner, in the above-described embodiment, whether or not the misfire rate R obtained from the misfire rate map 200 based on the main chamber excess air ratio λ1 and the sub-chamber excess air rate λ2 exceeds the threshold value Rth (that is, the misfire rate map 200 The opening command value I is determined based on the fixed value (Imem, for example, zero) stored in the memory 38 and the feedback control calculation by the first command value calculation unit 24. The calculated value (feedback command value I _FB ) is switched.
Therefore, when the obtained misfire rate R is not in the misfire ranges A1 and A2 (that is, when the misfire rate R is in the stable combustion range A0), the opening degree adjustment by feedback control is performed to The pre-chamber differential pressure can be brought closer to the target value by finely adjusting the fuel gas supply amount, and the opening command value I is set to zero when the acquired misfire rate R falls within the misfire ranges A1 and A2. By doing so, it is possible to cut off the fuel supply and reliably avoid a misfire in the subchamber. As a result, it is possible to suppress a significant decrease in the engine speed when a load is applied, and the engine can be operated stably even when a load is applied.

In some embodiments, the gas engine 3 includes a plurality of main chambers 307 each defined by a plurality of cylinders 301 and a piston 303, and a plurality of auxiliary chambers 315 and a plurality of auxiliary chambers 315 respectively provided corresponding to the plurality of main chambers 307. The subchamber gas adjustment valve 75 may also be included. In this case, the pre-chamber excess air ratio calculation unit 28 may be configured to estimate the pre-chamber excess air ratio λ2 for each of the plurality of cylinders 301 based on the flow coefficient for each of the plurality of cylinders 301. good.

When the gas engine 3 includes a plurality of cylinders 301 and pistons 303, the nozzle diameter of the auxiliary chamber 315 varies depending on the cylinder 301, so even if the above-mentioned auxiliary chamber differential pressure (P2-P1) is the same, the main The flow rate of the air-fuel mixture flowing into the auxiliary chamber 315 from the chamber 307 may vary from cylinder to cylinder (that is, the flow coefficient may differ from cylinder to cylinder).
In this regard, according to the above-described embodiment, the pre-chamber excess air ratio λ2 for each of the plurality of cylinders 301 is calculated in consideration of the flow coefficient for each cylinder 301. By using the estimated value of the pre-chamber excess air ratio λ2, it is possible to more accurately grasp the misfire rate R corresponding to the pre-chamber excess air ratio λ2. Therefore, for each of the plurality of cylinders 301, the opening command value of the pre-chamber gas adjustment valve 75 is set so that the estimated value of the obtained pre-chamber excess air ratio λ2 does not fall within the misfire regions A1 and A2 of the misfire rate map. By doing so, the amount of fuel gas supplied into the subchamber 315 can be adjusted more appropriately.

In the exemplary embodiment shown in FIG. 6, the command value setting section 20 includes a main chamber excess air ratio calculation section 26, an auxiliary chamber excess air ratio target value setting section 43, an auxiliary chamber differential pressure target value calculation section 44, a second It includes a command value calculation unit 48 and the like.

Similar to the embodiment shown in FIG. 3, the main chamber excess air ratio calculation unit 26 calculates the main chamber excess air ratio λ1, which is the excess air ratio of the air-fuel mixture supplied to the main chamber 307, and The ratio λ1 is output to the subchamber excess air ratio target value setting section 43 and the subchamber differential pressure target value calculation section 44.

The pre-chamber excess air ratio target value setting unit 43 acquires the misfire rate map 201 from the storage unit 34 and sets the target pre-chamber excess air ratio target value λ2*(target pre-chamber excess air ratio) based on the misfire rate map 201. λ2*).

Here, FIG. 7 is an example of the misfire rate map 201. The misfire rate map 201 shown in FIG. 7 is basically the same map as the misfire rate map 200 shown in FIG. 4, but the misfire rate map 201 shown in FIG. A minimum misfire rate curve Lmin is shown that represents a combination of the main chamber excess air ratio λ1 and the sub-chamber excess air ratio λ2 that result in a ratio Rmin.

The sub-chamber excess air ratio target value setting unit 43 sets the current main-chamber excess air ratio λ1 based on the current main-chamber excess air ratio λ1 received from the main-chamber excess air ratio calculation unit 26 and the minimum misfire rate curve Lmin of the misfire rate map 201. A target value λ2* of the sub-chamber excess air ratio λ2 corresponding to the excess room air ratio λ1 is obtained. The target value λ2* of the subchamber excess air ratio λ2 obtained in this way is output to the subchamber differential pressure target value calculation unit 44.

The pre-chamber differential pressure target value calculation unit 44 calculates a target value of the pre-chamber differential pressure corresponding to the target value λ2* of the pre-chamber excess air ratio λ2. More specifically, by performing the flow shown in FIG. 5 in reverse order, the target value of the subchamber differential pressure (target subchamber differential pressure) corresponding to the target value λ2* of the subchamber excess air ratio λ2 is calculated.

That is, first, based on the target value λ2* of the pre-chamber excess air ratio λ2, the amount of air and fuel gas in the pre-chamber 315 at the ignition timing such that this target value is obtained is calculated (see step S8). Based on the air amount and fuel gas amount in the sub chamber 315 at the ignition timing obtained by calculation, the air amount and fuel gas amount in the sub chamber 315 before ignition are determined so that these air amounts and fuel gas amounts can be obtained. The amount is calculated (see step S6). Then, based on the calculated air amount and fuel gas amount in the auxiliary chamber 315 before ignition, the fuel gas supply amount to the auxiliary chamber 315 is calculated so that these air amounts and fuel gas amounts can be obtained. (See step S4). Then, based on the calculated fuel gas supply amount, a target value of the subchamber differential pressure (target subchamber differential pressure) necessary to obtain the fuel gas supply amount is calculated (see step S2).

The target value of the subchamber differential pressure calculated by the subchamber differential pressure target value calculation unit 44 is input to the subtractor 46 . The actual pre-chamber pressure difference (P2-P1) is also input to the subtractor 46, and the subtracter 46 calculates the deviation (difference) between the actual pre-chamber pressure difference and the above-mentioned target value.

The deviation between the actual value of the pre-chamber differential pressure calculated by the subtractor 46 and the target value is inputted to the second command value calculation unit 48. The second command value calculation unit 48 calculates a feedback command value related to the opening degree of the sub-chamber gas regulating valve 75 based on the deviation, and directs this to the pre-chamber gas regulating valve 75 as the opening command value I. and output it. In this case, the opening degree of the subchamber gas adjustment valve 75 is adjusted to match the calculated feedback command value. That is, the opening degree of the subchamber gas regulating valve 75 is controlled so that the subchamber differential pressure becomes the target subchamber differential pressure, and the subchamber excess air ratio λ2 approaches the target subchamber excess air ratio λ2*. be done.
Note that, like the first command value calculation unit 24, the second command value calculation unit 48 may be a PI controller or a PID controller.

In the embodiment described above, the command value setting unit 20 selects the combination of the main chamber excess air ratio λ1 and the pre-chamber excess air ratio λ2 that minimizes the misfire rate R on the misfire rate map 201 at least when the engine load increases. Based on the minimum misfire rate curve Lmin representing It is configured to set the opening degree command value I of the subchamber gas regulating valve 75.

Therefore, by adjusting the amount of fuel gas supplied to the auxiliary chamber 315 based on the opening command value I set in this way, even if the main chamber excess air ratio λ1 is relatively small, the amount of air in the auxiliary chamber can be adjusted. It is possible to prevent the excess rate λ2 from becoming excessively small and appropriately avoid misfire in the subchamber.

In some embodiments, the map acquisition unit 32 (see FIGS. 3 and 6) described above determines the operating conditions of the gas engine 3 (for example, the outside temperature, the temperature of the air-fuel mixture supplied to the main chamber 307, or the fuel gas The misfire rate maps 200 and 201 may be acquired according to the characteristics of the engine, etc.).

For example, in one embodiment, the storage unit 34 may store a plurality of misfire rate maps 200 and 201 corresponding to a plurality of different operating conditions. Further, the misfire rate acquisition unit 30 (see FIG. 3) or the pre-chamber excess air ratio target value setting unit 43 (see FIG. 6) selects a misfire rate map 200 that matches the current operating conditions from a plurality of misfire rate maps 200, 201. , 201 may be selected and acquired.

Alternatively, in one embodiment, the control device 5 may include a map correction unit (not shown) that corrects the misfire rate maps 200 and 201 stored in the storage unit 34 in accordance with current driving conditions. Further, the misfire rate acquisition unit 30 (see FIG. 3) or the pre-chamber excess air ratio target value setting unit 43 (see FIG. 6) acquires the misfire rate maps 200, 201 after correction by the map correction unit described above. It may be.

According to the embodiment described above, since the opening command value I can be set using the misfire rate maps 200 and 201 according to the operating conditions of the gas engine 3, the main chamber excess air ratio λ1 and the subchamber excess air ratio Based on the rate λ2, a misfire rate R depending on the operating conditions of the gas engine 3 can be obtained. Therefore, based on the misfire rate R obtained in this way, the opening degree command value I of the pre-chamber gas regulating valve 75 can be set more appropriately. Therefore, even if the main chamber excess air ratio λ1 is relatively small, the amount of fuel gas supplied into the auxiliary chamber 315 can be adjusted more appropriately to prevent the auxiliary chamber excess air ratio λ2 from becoming excessively small. This can prevent misfires in the subchamber.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and also includes forms in which modifications are made to the above-described embodiments and forms in which these forms are appropriately combined.

In this specification, expressions expressing relative or absolute arrangement such as "in a certain direction", "along a certain direction", "parallel", "perpendicular", "center", "concentric", or "coaxial" are used. shall not only strictly represent such an arrangement, but also represent a state in which they are relatively displaced with a tolerance or an angle or distance that allows the same function to be obtained.
For example, expressions such as "same,""equal," and "homogeneous" that indicate that things are in an equal state do not only mean that things are exactly equal, but also have tolerances or differences in the degree to which the same function can be obtained. It also represents the existing state.
In addition, in this specification, expressions expressing shapes such as a square shape or a cylindrical shape do not only mean shapes such as a square shape or a cylindrical shape in a strict geometric sense, but also within the range where the same effect can be obtained. , shall also represent shapes including uneven parts, chamfered parts, etc.
Furthermore, in this specification, the expressions "comprising,""including," or "having" one component are not exclusive expressions that exclude the presence of other components.

1 Gas engine system 3 Gas engine 4 Crankshaft 5 Control device 11 Supercharger 11a Compressor 11b Exhaust turbine 13 Flywheel 15 Generator 17 Air cleaner 19 Gas mixer 20 Command value setting section 22 Subtractor 24 First command value calculation section 26 Main chamber Excess air ratio calculation section 28 Excess air ratio calculation section 30 Misfire rate acquisition section 34 Storage section 36 Comparison section 38 Memory 40 Switch 42 Excess air ratio acquisition section 44 Excess chamber air ratio calculation section 46 Subtractor 48 Second command value calculation unit 71 Fuel gas supply amount control unit 73 Air supply control valve 75 Pre-chamber gas adjustment valve 92 Air supply pressure sensor 93 Load sensor 94 Pre-chamber gas pressure sensor 95 Rotational speed sensor 101 Fuel gas supply line 103 Air supply Line 103a Upstream air supply line 103b Air supply manifold 105 Pre-chamber gas supply line 107 Combustion air supply line 200 Misfire rate map 201 Misfire rate map 301 Cylinder 303 Piston 305 Cylinder liner 307 Main chamber 311 Intake port 313 Intake valve 315 Pre-chamber 317 Pre-chamber cap 319 Nozzle 321 Nozzle holder 323 Pre-chamber gas line 325 Ignition device 327 Check valve A0 Stable combustion region A1 Misfire region A2 Misfire region

Claims (8)

A main chamber defined by a cylinder and a piston, a sub-chamber having a nozzle and communicating with the main chamber via the nozzle, and a sub-chamber for adjusting the amount of fuel gas supplied to the sub-chamber. A gas engine control device comprising a gas regulating valve,
At least when the engine load increases, the main chamber excess air ratio λ1 is the excess air ratio of the mixture supplied to the main chamber, and the subchamber excess air ratio λ2 is the excess air ratio of the gas in the subchamber at the time of ignition. , and an opening command value for the pre-chamber gas regulating valve so that the pre-chamber excess air ratio λ2 does not fall into the misfire region in the misfire rate map, based on a misfire rate map showing the correlation between the misfire rates. Equipped with a command value setting section configured to set the
The command value setting unit sets the opening command value when a misfire rate obtained by applying the main chamber excess air ratio λ1 and the auxiliary chamber excess air ratio λ2 to the misfire rate map enters the misfire region. A gas engine control device configured to set zero as . At least the pressure P1 of the air-fuel mixture supplied to the main chamber, the main chamber excess air ratio λ1, and the difference between the pressure P2 of the fuel gas supplied to the auxiliary chamber and the pressure P1 in the auxiliary chamber. The gas engine control device according to claim 1, further comprising a pre-chamber excess air ratio calculation unit configured to estimate the pre-chamber excess air ratio λ2 based on the differential pressure (P2-P1). The gas engine includes a plurality of main chambers each defined by a plurality of cylinders and a piston, and a plurality of auxiliary chambers and a plurality of auxiliary chamber gas adjustment valves respectively provided corresponding to the plurality of main chambers,
3. The subchamber excess air ratio calculation unit is configured to estimate the subchamber excess air ratio λ2 for each of the plurality of cylinders based on a flow coefficient for each of the plurality of cylinders. A control device for the gas engine described above. The command value setting unit obtains a target sub-chamber excess air ratio λ2* at which the misfire rate is minimal with respect to the current main-chamber excess air ratio λ1, based on the misfire rate map, at least when the engine load increases. The sub-chamber differential pressure (P2-P1), which is the difference between the pressure P2 of the fuel gas supplied to the sub-chamber and the pressure P1 of the air-fuel mixture supplied to the main chamber, is the target sub-chamber pressure. 4. The opening command value of the pre-chamber gas regulating valve is configured to be set to a target pre-chamber differential pressure corresponding to an excess air ratio λ2*. Gas engine control device. comprising a map acquisition unit that acquires the misfire rate map according to operating conditions of the gas engine,
The gas according to any one of claims 1 to 4, wherein the command value setting unit is configured to set the opening command value using the misfire rate map acquired by the map acquisition unit. Engine control device. The gas engine control device according to claim 5, wherein the operating condition includes at least one of an outside temperature, a temperature of the air-fuel mixture supplied to the main chamber, or a property of the fuel gas. a main chamber defined by a cylinder and a piston;
a sub-chamber having a spout and communicating with the main chamber via the spout;
A gas engine including a subchamber gas adjustment valve for adjusting the amount of fuel gas supplied to the subchamber;
A control device according to any one of claims 1 to 6 for controlling the gas engine;
Gas engine system with. A main chamber defined by a cylinder and a piston, a sub-chamber having a nozzle and communicating with the main chamber via the nozzle, and a sub-chamber for adjusting the amount of fuel gas supplied to the sub-chamber. A program for controlling a gas engine including a gas regulating valve,
At least when the engine load increases, the main chamber excess air ratio λ1 is the excess air ratio of the air-fuel mixture supplied to the main chamber, and the pre-chamber excess air ratio λ2 is the excess air ratio of the gas in the auxiliary chamber at the time of ignition. , and based on a misfire rate map showing the correlation between the misfire rates, an opening command value of the pre-chamber gas regulating valve is determined so that the pre-chamber excess air ratio λ2 does not fall into the misfire region in the misfire rate map. is configured to cause the computer to perform steps to configure the
In the procedure, when the misfire rate obtained by applying the main chamber excess air ratio λ1 and the auxiliary chamber excess air ratio λ2 to the misfire rate map enters the misfire region , zero is set as the opening command value. Gas engine control program to set.

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