Control device, control method, and program

Abstract

A control device capable of suppressing the occurrence of abnormalities when transitioning between any operation modes is provided. [Solution] The control device includes a control unit that, when transitioning the engine operating mode from a first operating mode to a second operating mode, transitions from the first operating mode to a safe mode, which is a common operating mode designed to enable abnormalities to be avoided, and transitions from the safe mode to the second operating mode.

Description

[Technical Field]

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

[0002] When changing settings such as engine ignition timing and air-fuel ratio in response to changes in fuel properties, such as when switching fuel, if the timing and speed of the change in the settings do not match the fuel properties, the settings will no longer be appropriate for the constantly changing fuel properties, increasing the likelihood of abnormal combustion such as knocking or pre-ignition.In particular, when switching between natural gas and hydrogen or hydrogen-blended fuel, abnormal combustion such as knocking or pre-ignition is more likely to occur due to the influence of hydrogen, which has good ignition properties and a fast combustion speed.

[0003] However, it is difficult to uniquely determine the optimum value for the fuel properties at each moment, because the fuel properties at the engine inlet change depending on the operating load, plant layout, etc. One solution is to monitor the fuel properties at the engine inlet, but this increases the cost due to the increased equipment required.

[0004] Furthermore, if an abnormality avoidance mode is set up for each type of abnormality in case adjustment of settings such as ignition timing and air-fuel ratio does not go well, the number of operating modes will increase, making control more complex, and the increased number of settings will make it more likely that errors will occur during adjustment.

[0005] Regarding control when fuel properties change, Patent Document 1 discloses control that reduces NOx emissions when transitioning between a fuel-lean first combustion mode and a stoichiometric second combustion mode by first starting intake air cooling, then adjusting the intake air amount, and completing the switching between the first and second combustion modes after intake air cooling is complete. However, Patent Document 1 does not disclose control that suppresses the occurrence of abnormalities during the transition between any operating modes. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2023-34303 Summary of the Invention [Problem to be solved by the invention]

[0007] There is a demand for technology that can suppress the occurrence of abnormalities regardless of the transition between operating modes.

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

[0009] The control device of the present disclosure includes a control unit that, when transitioning an engine operation mode from a first operation mode to a second operation mode, transitions from the first operation mode to a safe mode, which is a common operation mode in which set values ​​of control parameters are designed to enable abnormalities to be avoided, and transitions from the safe mode to the second operation mode. The control unit then retards the ignition timing of the spark plug by a predetermined amount, then increases the air-fuel ratio by a predetermined amount, then retards the fuel gas supply timing by a predetermined amount, and then reduces the auxiliary chamber fuel gas flow rate by a predetermined amount, thereby transitioning to the safe mode.

[0010] In the control method of the present disclosure, when an engine control device transitions an operation mode of the engine from a first operation mode to a second operation mode, the control device transitions from the first operation mode to a safe mode, which is a common operation mode in which set values ​​of control parameters are designed to enable abnormalities to be avoided, and transitions from the safe mode to the second operation mode. When transitioning to the safe mode, the ignition timing of the spark plug is retarded by a predetermined amount, then the air-fuel ratio is increased by a predetermined amount, then the fuel gas supply timing is retarded by a predetermined amount, and then the pre-chamber fuel gas flow rate is reduced by a predetermined amount, thereby transitioning to the safe mode.

[0011] The program of the present disclosure causes a computer to function as a means for, when transitioning an engine operation mode from a first operation mode to a second operation mode, transitioning from the first operation mode to a safe mode, which is a common operation mode designed to enable abnormalities to be avoided, and transitioning from the safe mode to the second operation mode. When transitioning to the safe mode, the transitioning means retards the ignition timing of the spark plug by a predetermined amount, then increases the air-fuel ratio by a predetermined amount, then retards the fuel gas supply timing by a predetermined amount, and then reduces the pre-chamber fuel gas flow rate by a predetermined amount, thereby transitioning to the safe mode. [Effects of the Invention]

[0012] According to the above-described control device, gas engine, and control method, it is possible to suppress the occurrence of abnormalities in the transient state when transitioning between any operation modes. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic configuration diagram of a gas engine system according to an embodiment. [Figure 2] FIG. 1 is a diagram illustrating a conventional operation mode transition. [Figure 3] FIG. 4 is a diagram illustrating an operation mode transition according to the embodiment. [Figure 4] FIG. 1 is a diagram illustrating an example of conventional operation mode transition control. [Figure 5] FIG. 4 is a diagram illustrating an example of operation mode transition control according to the embodiment. [Figure 6] FIG. 4 is a diagram illustrating an example of an operation mode transition according to the embodiment. [Figure 7] 4 is a first flowchart showing an example of operation mode transition control according to the embodiment. [Figure 8] 6 is a second flowchart showing an example of operation mode transition control according to the embodiment. [Figure 9] FIG. 2 is a diagram illustrating an example of a hardware configuration of a control device according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] <Embodiment> (composition) Hereinafter, the control method for transitioning between operation modes according to the present disclosure will be described with reference to the drawings. 1 is a schematic diagram of an engine system 1 according to this embodiment. The engine system 1 includes a hydrogen mixing device 2, an engine 3, and a control device 10 that controls the engine 3.

[0015] The hydrogen mixing device 2 mixes natural gas, such as city gas, with hydrogen to produce a mixed fuel, and supplies the produced mixed fuel to the engine 3. The concentration of hydrogen in the mixed fuel is called the mixing ratio. The hydrogen mixing device 2 controls the mixing ratio to a desired value based on the load on the engine 3 and a fuel switching command output from a controller (not shown). The hydrogen mixing device 2 can also supply natural gas or hydrogen alone to the engine 3 as the fuel gas.

[0016] The engine 3 is a gas engine that uses a fuel gas mixture made by mixing natural gas with hydrogen, natural gas without hydrogen, or pure hydrogen as its fuel gas. It generates an air-fuel mixture by mixing the fuel gas supplied from the hydrogen mixing device 2 through a fuel supply line L1 with air supplied through an air supply line L2, and outputs power by burning the generated air-fuel mixture. The engine 3 includes the fuel supply line L1, the air supply line L2, an intake line L3 connected to lines L1 and L2 and used to generate the air-fuel mixture, a secondary fuel line L4 connected to the fuel supply line L1, an exhaust line L5, one or more cylinders 4, a piston 5 provided for each cylinder 4, a combustion chamber 6, a spark plug 7, and a secondary combustion chamber 8. The air-fuel mixture is supplied to the cylinder 4 through the intake line L3, and the fuel gas is supplied to the secondary combustion chamber 8 through the secondary combustion line L4. The flame formed by igniting the spark plug 7 in the secondary combustion chamber 8 is blown into the combustion chamber 6, where the air-fuel mixture is combusted. The exhaust gas after combustion is discharged through exhaust line L5. Exhaust line L5 is provided with sensor C2 that measures the temperature of the exhaust gas and sensor C3 that detects the components of the exhaust gas. Additionally, cylinder 4 is provided with sensor C1 that measures the pressure inside cylinder 4. Information measured by sensors C1, C2, and C3 is output to control device 10.

[0017] The control device 10 controls the engine 3. The control device 10 includes a signal acquisition unit 11, a determination unit 12, and a control unit 13. The signal acquisition unit 11 acquires information measured by each of the sensors C1 to C3 from the sensors C1 to C3. The signal acquisition unit 11 also acquires a fuel switching command, a set value of the mixing ratio in the hydrogen mixing device 2, or a measured value of the mixing ratio.

[0018] The determination unit 12 determines whether to transition the operation mode. For example, when a change in the mixture ratio (a change in the combustion properties) occurs, the determination unit 12 determines to transition the operation mode to an operation mode corresponding to the mixture ratio of hydrogen. In addition, in this embodiment, when transitioning from the first operation mode to the second operation mode, the transition to the second operation mode is performed via a common operation mode (referred to as a safe mode) in which the set values ​​of control parameters are designed so that no abnormality occurs regardless of the operation mode from which the transition is made. The determination unit 12 determines the timing of transition from the safe mode to the second operation mode. For example, the determination unit 12 may determine to transition to the second operation mode when fuel switching is completed, or when the state is stabilized after fuel switching is completed. Furthermore, regardless of the transition of the operation mode, the determination unit 12 determines whether abnormal combustion or the like has occurred during operation, and if an abnormality has occurred, determines to transition from the current operation mode to the safe mode. Then, after transitioning to the safe mode, the determination unit 12 determines whether the abnormality has been resolved, and if the abnormality has been resolved, determines to return to the original operation mode.

[0019] Regarding this abnormality determination, the determination unit 12 determines the combustion state of the engine 3. For example, if the pressure or pressure change per unit time measured by the sensor C1 deviates from a normal range, the determination unit 12 determines that abnormal combustion such as knocking has occurred, and if they fall within the normal range, the determination unit 12 determines that combustion is stable. Similarly, if the exhaust gas temperature or temperature change per unit time measured by the sensor C2 deviates from a normal range, the determination unit 12 determines that abnormal combustion has occurred, and if they fall within the normal range, the determination unit 12 determines that combustion is stable. Furthermore, if the exhaust gas components, component ratios, or component changes measured by the sensor C3 deviate from a normal range, the determination unit 12 determines that abnormal combustion has occurred, and if they fall within the normal range, the determination unit 12 determines that combustion is stable.

[0020] The control unit 13 operates the engine 3 by performing combustion control and air-fuel ratio control. In the combustion control, control is performed to set the engine speed and load to target values. For example, the control unit 13 controls the flow rate of fuel gas supplied to the auxiliary combustion chamber 8 by controlling the valve V3 and the like provided in the auxiliary fuel line L4, and controls to advance or delay the ignition timing of the spark plug 7 and the fuel gas supply timing at which fuel gas is injected from the fuel supply line L1 to the intake line L3. In the air-fuel ratio control, in order to maintain a constant air-fuel ratio in the combustion chamber of the engine 3, feedback control is performed to set the air-fuel ratio to a target value by controlling the valves V1, V2 and the like provided in the lines L1 to L3 that flow into the combustion chamber.

[0021] Furthermore, the control unit 13 controls the transition of the operation mode of the engine 3 based on the determination of the determination unit 12. The operation modes include, for example, an operation mode in which the engine 3 is operated solely on natural gas (operation mode 1), an operation mode in which the engine 3 is operated on a mixed fuel in which natural gas is mixed with hydrogen (operation mode 2), an operation mode in which the engine 3 is operated solely on hydrogen gas (operation mode 3), and a low-NOx mode in which NOx in the exhaust gas is reduced. For example, the control unit 13 acquires a set value of the mixing ratio from the hydrogen mixing device 2, and when the set value of the mixing ratio changes from 50% to 0%, the control unit 13 determines to operate the engine 3 in operation mode 1 and changes the operation mode of the engine 3 from operation mode 2 to operation mode 1. Similarly, when the set value of the mixing ratio changes from 0% to 50%, the control unit 13 changes the operation mode from operation mode 1 to operation mode 2. Furthermore, when an instruction to operate in the low-NOx mode is issued, the control unit 13 changes the operation mode from another operation mode to the low-NOx mode.

[0022] When changing the operation mode, the control unit 13 changes the set values ​​of control parameters such as the load, rotation speed, ignition timing, ignition energy, air-fuel ratio, intake air temperature, fuel gas flow rate, fuel gas supply pressure, fuel gas temperature, fuel gas supply timing, pre-chamber fuel gas flow rate supplied to the pre-chamber 8, pre-chamber fuel gas supply pressure, pre-chamber fuel gas temperature, pre-chamber fuel gas supply timing, coolant temperature, coolant pressure, coolant flow rate, lubricating oil temperature, lubricating oil pressure, lubricating oil flow rate, and valve timing, as well as the set values ​​of other parameters that directly or indirectly affect these parameters.

[0023] Furthermore, when the hydrogen concentration is changed when switching between operation modes, the control unit 13 also switches the purging of the crankcase of the engine 3 ON / OFF. This is because if the fuel gas contains hydrogen, there is a possibility that unburned gas will ignite in the crankcase, making purging necessary to ensure safety. For example, when operating in operation mode 2, the control unit 13 turns purging ON. When transitioning from operation mode 2 to operation mode 1, the control unit 13 turns purging ON after transitioning to safe mode and until the transition from safe mode to operation mode 1 begins (until fuel switching is completed or for a while after switching is completed), and then turns purging OFF. Similarly, when transitioning from operation mode 1 to operation mode 2, the control unit 13 turns purging OFF while operation mode 1 is being executed, and turns purging ON when transitioning to safe mode (simultaneously with the start of fuel switching).

[0024] Next, we will explain the operation mode transition method. Figure 2 shows an example of a conventional operation mode transition. In conventional operation mode transitions, the transition between operation modes is performed directly, such as from operation mode A to normal mode B and from normal mode B to operation mode C. When the operation mode transition involves a change in fuel properties (e.g., a change in hydrogen concentration), if the changes in the control parameter settings do not accurately track the changes in the fuel properties at the engine inlet, abnormal combustion such as knocking or pre-ignition may occur. Generally, avoidance modes such as Abnormality Avoidance 1 and Abnormality Avoidance 2 (avoidance modes are a type of operation mode) are prepared for each type of abnormal combustion that may occur. If abnormal combustion occurs during an operation mode transition, the system transitions to the avoidance mode corresponding to the abnormal combustion. Once the abnormal condition is resolved, the system transitions to the original operation mode or the destination operation mode. As shown in Figure 2, conventional operation mode transitions increase the number of operation modes (including avoidance modes) and the transition patterns (arrows in Figure 2), making control more complex. Furthermore, the increase in set values ​​makes it more likely that setting errors will occur during adjustment. Therefore, in this embodiment, a safe mode is provided as a common avoidance mode that can reliably avoid abnormalities, and when transitioning to a different operation mode, the system always transitions to the safe mode first, and then transitions to or returns to the desired operation mode. The avoidance modes that were provided for each type of abnormality in conventional control are unified into a single safe mode. The set values ​​of the control parameters for the safe mode are considered and designed so that abnormalities can be avoided when transitioning from any operation mode, or so that even if an abnormality occurs during operation in such an operation mode, the safe mode can be directed toward eliminating the abnormality (so that the safe mode functions as an avoidance mode for all abnormalities).

[0025] FIG. 3 shows an example of the transition of operation modes in this embodiment. In this embodiment, when transitioning from normal mode B to operation mode A, the normal mode B is transitioned to safe mode, and then the safe mode is transitioned to operation mode A. For example, in the case of a transition of operation modes involving fuel switching (such as changing the fuel property from natural gas alone to a hydrogen-blended fuel), the normal mode B is transitioned to safe mode as soon as the fuel switching begins. Then, once the fuel switching is completed, the safe mode is transitioned to operation mode A. The transition from safe mode to operation mode A may be simultaneous with the completion of the fuel switching, or may be delayed for a certain period of time after the fuel switching for a safer transition. The safe mode is an operation mode that can reliably avoid abnormalities. Therefore, in the safe mode, control parameters (such as retarding the ignition timing and increasing the air-fuel ratio) are changed to weaken combustion within a range that does not cause misfires. When transitioning from the safe mode to another operation mode, combustion is controlled to be strengthened. In this case, in order to prevent abnormal combustion due to a sudden change in the control parameter setting, it is preferable to transition from the safe mode to the desired operation mode in a gradual manner (over a predetermined time). For example, the air-fuel ratio is reduced and the ignition timing is advanced in small increments. Also, if an abnormality occurs while normal mode B or operation mode A is being executed, the operation mode switches to a common avoidance mode, safe mode, and returns to the original operation mode after the abnormality is resolved. In this way, the introduction of a common safe mode ensures stable operation in a transient state. This eliminates the need to consider transitioning to other operation modes when in the operation mode from which or after the transition, and allows the setting values ​​of the control parameters to be optimized (highly efficient) for each operation mode.

[0026] Next, a specific example of control when the operation mode is changed will be described. An example of transition from operation mode 2, in which the hydrogen concentration in the fuel gas at the inlet of engine 3 is 50%, to operation mode 1, in which the hydrogen concentration in the fuel gas at the inlet of engine 3 is 0% will be described. First, conventional control will be described with reference to FIG. 4. Diagram 41 (top) of FIG. 4 shows the transition of hydrogen concentration in the fuel gas. The vertical axis of FIG. 41 represents hydrogen concentration, and the horizontal axis represents the elapsed time since the fuel switch command was output. Diagram 42 (bottom) of FIG. 4 shows the transition of ignition timing of the spark plug 7 as an example of a control parameter. The vertical axis of FIG. 42 represents ignition timing, and the horizontal axis represents the elapsed time since the fuel switch command was output. Because there is a distance between the hydrogen mixing device 2 and the engine 3, there is a time lag between the output of the fuel switch command and the actual start of a change in the fuel properties at the inlet of engine 3. Furthermore, because the hydrogen concentration is not immediately switched from 50% to 0% after the fuel switch command is output, it takes time for the fuel properties at the inlet of engine 3 to completely switch from the state assumed in operation mode 2 to the state assumed in operation mode 1. In other words, the hydrogen concentration at the inlet of the engine 3 gradually decreases from 50% to 0% with a short delay after the fuel switch command is output. Conventional control gradually retards the ignition timing in accordance with this decrease in hydrogen concentration. In this case, for example, a set value for each moment, as shown by the solid line in Figure 42, is prepared in advance, and the ignition timing is controlled according to this set value. However, if the optimum value for the ignition timing according to the fuel properties at each moment actually changes as shown by the dashed line in Figure 42, the ignition timing at each moment will be shifted more advanced than the optimum value, raising concerns about abnormal combustion such as knocking.

[0027] In contrast, in this embodiment, the transition from operation mode 1 to operation mode 2 is performed using control such as that shown in FIG. 5. The vertical and horizontal axes in the upper and lower diagrams 51 and 52 of FIG. 5 are the same as those in FIGS. 41 and 42, respectively. FIG. 51 also shows the same transition of hydrogen concentration as in FIG. 41. In this embodiment, when a fuel switch command is output during operation in operation mode 2, the system transitions to safe mode rather than operation mode 1. At this time, the control unit 13 changes the control parameters in the following order: (1) retard the ignition timing; (2) increase the air-fuel ratio; (3) retard the fuel gas supply timing; and (4) reduce the pre-chamber fuel gas flow rate to the pre-chamber 8. The extent to which the ignition timing and fuel gas supply timing are retarded, and the air-fuel ratio and fuel gas flow rate are set are determined in advance so that no problems arise regardless of the operation mode or abnormal state from which the system transitions (a common avoidance mode that can avoid abnormalities). Changing the set values ​​of the control parameters in the above order makes it possible to maintain stable combustion while avoiding a transient excessive increase in in-cylinder pressure. The dashed line in Figure 52 indicates the optimum value for ignition timing at each moment, and the solid line in Figure 52, 0 to 6 seconds, indicates the set value for ignition timing in safe mode.

[0028] Furthermore, when transitioning from safe mode to a predetermined operation mode, the control unit 13 changes the control parameters in the following order: (1) Increase the flow rate of the pre-chamber fuel gas supplied to the pre-chamber 8; (2) Advance the fuel gas supply timing; (3) Decrease the air-fuel ratio; and (4) Advance the ignition timing. By controlling in this order, it is possible to maintain stable combustion while avoiding the occurrence of abnormal combustion. In the solid line in Figure 52, the setting value of the ignition timing after 6 seconds is the setting value when transitioning from safe mode to operation mode 2. As mentioned above, it is preferable to transition from safe mode to another operation mode in a gradual manner. The gradual advance of the ignition timing after 6 seconds in Figure 52 is an example of a gradual transition.

[0029] Note that when transitioning from operation mode 1 (0% hydrogen concentration) to safe mode or from operation mode 2 (50% hydrogen concentration) to safe mode, the change in the set values ​​of the control parameters during the transition to safe mode is large, which may result in unstable combustion or a deterioration in efficiency. For example, comparing the control parameters of operation modes 1 and 2, operation mode 2 has a retarded ignition timing and a higher air-fuel ratio than operation mode 1. Therefore, when transitioning from operation mode 1 to safe mode, which further retards the ignition timing and sets a higher air-fuel ratio, the change in the set values ​​of the ignition timing and air-fuel ratio becomes larger than when transitioning from operation mode 2 to safe mode. In this case, there are concerns about unstable combustion and a deterioration in efficiency. Furthermore, if abnormal combustion occurs during operation in operation mode 2, the engine switches to safe mode and then returns to it, the time it takes to stabilize operation by switching back and forth between operation mode 2 and safe mode is longer due to the large difference in set values, resulting in a longer operation time in an inefficient state. In order to deal with such situations, instead of providing one unified safe mode, two types of safe modes may be provided: a safe mode 1 for operation mode 1 that is used when transitioning from operation mode 1, and a safe mode 2 for operation mode 2 that is used when transitioning from operation mode 2. Comparing the set values ​​of the control parameters of safe mode 1 and safe mode 2, the set values ​​of safe mode 1 are designed to be relatively close to the set values ​​of the control parameters of operation mode 1, and the set values ​​of safe mode 2 are designed to be relatively close to the set values ​​of the control parameters of operation mode 2. By providing multiple safe modes according to operating conditions (for example, fuel properties), it is possible to suppress excessive deterioration in efficiency and destabilization of operation due to avoidance operations to switch to safe mode.

[0030] Fig. 6 shows an example of the operation mode transition when two types of safe modes are provided. For example, when transitioning from operation mode 1 to operation mode 2, as shown in Figure 6(a), the operation mode 1 transitions to safe mode 1, and when certain conditions are met, such as a predetermined time having passed or the mixture ratio reaching a predetermined value or greater, the operation mode transitions from safe mode 1 to safe mode 2, and when the fuel is switched and operation is stabilized, the operation mode transitions from safe mode 2 to operation mode 2. Similarly, when transitioning from operation mode 2 to operation mode 1, as shown in Figure 6(b), the system transitions from operation mode 2 to safe mode 2, and when certain conditions are met, it transitions from safe mode 2 to safe mode 1, and when the fuel is switched and operation is stabilized, it transitions from safe mode 1 to operation mode 1.

[0031] Furthermore, if an abnormality occurs during operation in operation mode 1, as shown in FIG. 6(c), the operation mode 1 is switched to safe mode 1, and when the abnormality is resolved, the operation mode 1 is restored. Similarly, if an abnormality occurs during operation in operation mode 2, as shown in FIG. 6(d), the operation mode 2 is switched to safe mode 2, and when the abnormality is resolved, the operation mode 2 is restored.

[0032] (operation) Next, the flow of control during transition of the operation mode will be described with reference to FIGS. An example of control for transitioning the operation mode from the first operation mode to the second operation mode is shown in Fig. 7. It is assumed that the engine 3 is operating in the first operation mode. First, the determination unit 12 determines whether or not to transition from the first operation mode to the second operation mode (step S1). If the first operation mode is operation mode 1 and the second operation mode is operation mode 2, when the set value or actual measurement value of the hydrogen mixing ratio acquired by the signal acquisition unit 11 from the hydrogen mixing device 2 changes from 0%, the determination unit 12 determines that the operation mode will transition from operation mode 1, which corresponds to a mixing ratio of 0%, to operation mode 2. Alternatively, when the signal acquisition unit 11 acquires a fuel switching signal instructing a change in the mixing ratio from 0% to 50%, the determination unit 12 determines that the operation mode will transition from operation mode 1 to operation mode 2. If there is no change in the mixing ratio, the determination unit 12 determines that the operation mode will not transition from operation mode 1 to operation mode 2. Also, for example, when the first operation mode is operation mode 1 and the second operation mode is low NOx mode, if the signal acquisition unit 11 acquires a command signal instructing switching to the low NOx mode, the determination unit 12 determines that the operation mode will transition to the low NOx mode, and if no command signal is acquired, the determination unit 12 determines that the operation mode will not transition to the low NOx mode. If it is determined that the operation mode will not transition to the second operation mode (step S1; No), the determination of step S1 is repeated.

[0033] When the determination unit 12 determines that the operation mode will transition from the operation mode 1 to the operation mode 2 (step S1; Yes), the control unit 13 transitions from the first operation mode to the safe mode (step S2). The control unit 13 changes the set values ​​of these control parameters in the following order to transition to the safe mode: (1) retard the ignition timing, (2) increase the air-fuel ratio, (3) retard the fuel gas supply timing, and (4) decrease the flow rate of the auxiliary chamber fuel gas.

[0034] Next, the determination unit 12 determines whether a transition condition for transitioning from the safe mode to the operation mode 2 is met (step S3). For example, when transitioning to the operation mode 2, the determination unit 12 determines that the condition for transitioning from the safe mode to the operation mode 2 is met when the hydrogen mixing ratio obtained from the hydrogen mixing device 2 reaches 50%. Alternatively, the determination unit 12 may determine that the condition for transitioning to the operation mode 2 is met when a predetermined time has elapsed since the mixing ratio reached 50%, or may determine that the transition condition is met when the mixing ratio reaches 50% and the determination result of the combustion state based on the sensors C1 to C3 indicates stable combustion. If these transition conditions are not met (step S3; No), the determination unit 12 repeats the determination of step S3 until the transition condition is met. If the transition condition is met (step S3; Yes), the control unit 13 transitions from the safe mode to the second operation mode (step S4). The control unit 13 changes the set values ​​of these control parameters in the following order to transition to the second operating mode: (1) increase the flow rate of the pre-chamber fuel gas supplied to the pre-chamber 8 in a ramp or step manner to the set value for the second operating mode; (2) advance the fuel gas supply timing in a ramp or step manner to the set value for the second operating mode; (3) decrease the air-fuel ratio in a ramp or step manner to the set value for the second operating mode; and (4) advance the ignition timing in a ramp or step manner to the set value for the second operating mode.

[0035] When changing the hydrogen mixing ratio from 0% to 50%, the safe mode may be divided into two types, and transitions may be made in the following order: operation mode 1, safe mode 1, safe mode 2, and operation mode 2. In this case, transitions between safe mode 1 and safe mode 2 may be made by transitioning to safe mode 1 and then transitioning to safe mode 2 when a predetermined time has elapsed, or by transitioning to safe mode 1 and then transitioning to safe mode 2 when the mixing ratio reaches a predetermined value. The determination of the conditions for transitioning from safe mode 2 to operation mode 2 may be the same as in step S3.

[0036] In addition, in the explanation of Figure 7, the first operation mode is operation mode 1 and the second operation mode is operation mode 2. However, for example, even if the first operation mode is operation mode 1 and the second operation mode is operation mode 3 (100% hydrogen), a transition from the first operation mode to the second operation mode can be achieved by similar control.

[0037] Next, with reference to FIG. 8, the flow of control when an abnormality occurs during operation in a certain operation mode will be described. The determination unit 12 detects the occurrence of an abnormality during the first operation mode (step S11). For example, the determination unit 12 determines the combustion state based on the sensors C1 to C3, and if a value measured by any of the sensors or a change in the measured value deviates from a normal range, the determination unit 12 determines that an abnormality has occurred (detection of the occurrence of an abnormality).

[0038] When the occurrence of an abnormality is detected, the control unit 13 transitions from the first operation mode to the safe mode (step S12). This process is the same as step S2 in FIG.

[0039] Next, the determination unit 12 determines whether the abnormality has been resolved (step S13). For example, the determination unit 12 determines the combustion state based on the sensors C1 to C3, and determines that the abnormality has been resolved if the values ​​measured by each sensor and changes in the measured values ​​are all within normal ranges. If this condition is not met (step S13; No), the determination unit 12 repeats the determination in step S13 until the condition is met.

[0040] When the abnormality is resolved (Step S13; Yes), the control unit 13 returns from the safe mode to the first operation mode (Step S14). The control unit 13 changes the set values ​​of these control parameters in the following order to return to the first operation mode: (1) increase the flow rate of the auxiliary chamber fuel gas in a ramp or step manner to the set value for the first operation mode, (2) advance the fuel gas supply timing in a ramp or step manner to the set value for the first operation mode, (3) decrease the air-fuel ratio in a ramp or step manner to the set value for the first operation mode, and (4) advance the ignition timing in a ramp or step manner to the set value for the first operation mode.

[0041] (effect) As described above, according to this embodiment, when transitioning between operation modes, the system first passes through the safe mode before transitioning to the destination operation mode. This makes it possible to suppress the occurrence of abnormalities in the transition state, regardless of the transition between operation modes. Furthermore, by consolidating the avoidance modes in the event of an abnormality into the safe mode, it is possible to suppress the complexity of the control logic in the event of an abnormality and reduce the number of set value patterns. For example, by reducing the number of transition patterns between operation modes, it is possible to minimize set values ​​such as the transition speed. Furthermore, by ensuring stable operation in the transition state using the safe mode, it is possible to optimize (highly efficient) the set values ​​of the control parameters for each operation mode.

[0042] 9 is a schematic block diagram showing the hardware configuration of a control device according to an embodiment. A computer 90 includes a processor 91, a main memory 92, a storage 93, and an interface 94. The above-described control device 10 is implemented in the computer 90. The operations of each of the above-described processing units are 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-described processing in accordance with the program. The processor 91 also allocates storage areas in the main memory 92 corresponding to each of the above-described storage units in accordance with the program. Examples of the processor 91 include a CPU (Central Processing Unit), a GPU (Graphic Processing Unit), and a microprocessor.

[0043] The program may be for realizing some of the functions to be performed by the computer 90. For example, the program may be combined with other programs already stored in storage or implemented in other devices to perform the functions. In other embodiments, the computer 90 may include 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 realized by the processor 91 may be realized by the integrated circuit. Such an integrated circuit is also an example of a processor.

[0044] Examples of storage 93 include a hard disk drive (HDD), a solid state drive (SSD), a magnetic disk, a magneto-optical disk, a compact disc read-only memory (CD-ROM), a digital versatile disc read-only memory (DVD-ROM), and a semiconductor memory. Storage 93 may be an internal medium directly connected to the bus of computer 90, or an external medium connected to computer 90 via interface 94 or a communication line. Furthermore, if this program is distributed to computer 90 via a communication line, computer 90 receiving the program may load the program into main memory 92 and execute the above-described processing. In at least one embodiment, storage 93 is a non-transitory tangible storage medium. Furthermore, the program may be for implementing some of the above-described functions. Furthermore, the program may be a so-called differential file (differential program) that realizes the above-described functions in combination with another program already stored in storage 93.

[0045] As described above, several embodiments according to the present disclosure have been described, but all of these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope of the invention and its equivalents as defined in the claims, as well as in the scope and spirit of the invention.

[0046] <Additional Notes> The control device, control method, and program described in each embodiment can be understood, for example, as follows.

[0047] (1) A control device according to a first aspect includes a control unit that, when transitioning an engine operation mode from a first operation mode to a second operation mode, transitions from the first operation mode to a safe mode, which is a common operation mode in which the setting values ​​of control parameters are designed to enable abnormalities to be avoided, and transitions from the safe mode to the second operation mode. This makes it possible to suppress the occurrence of abnormalities in the transient state when transitioning between any operation modes.

[0048] (2) A control device according to a second aspect is the control device of (1), in which the control unit transitions to the safe mode by retarding the ignition timing of the spark plug by a predetermined amount, then increasing the air-fuel ratio by a predetermined amount, then retarding the fuel gas supply timing by a predetermined amount, and then decreasing the auxiliary chamber fuel gas flow rate by a predetermined amount. This allows the first operation mode to be transitioned to the safe mode.

[0049] (3) A control device according to a third aspect is the control device of (1) to (2), wherein the control unit transitions to the second operation mode by increasing the flow rate of the auxiliary chamber fuel gas, advancing the fuel gas supply timing, decreasing the air-fuel ratio, and advancing the ignition timing. This allows the safe mode to be switched to the second operating mode.

[0050] (4) A control device according to a fourth aspect is the control device according to any one of (1) to (3), wherein the control unit transitions to the second operation mode by increasing the flow rate of the pre-chamber fuel gas to the flow rate of the pre-chamber fuel gas in the second operation mode over a predetermined time, advancing the fuel gas supply timing to the fuel gas supply timing in the second operation mode over a predetermined time, decreasing the air-fuel ratio to the air-fuel ratio in the second operation mode over a predetermined time, and advancing the ignition timing to the ignition timing in the second operation mode over a predetermined time. This allows the safe mode to be switched to the second operating mode.

[0051] (5) A control device according to a fifth aspect is a control device according to any one of (1) to (4), in which the first operating mode is an operating mode using only natural gas as fuel, and the second operating mode is an operating mode using a mixed fuel of natural gas and hydrogen or only hydrogen as fuel. This allows for transition between an operation mode using hydrogen co-combustion and an operation mode using only city gas.

[0052] (6) A control device according to a sixth aspect is the control device described in (5), further comprising a determination unit that acquires the hydrogen mixing ratio in the fuel and determines that the operation mode will transition from the first operation mode to the second operation mode when the mixing ratio changes from 0%. This makes it possible to determine whether to execute and start a mode transition between an operation mode using mixed hydrogen combustion and an operation mode using only city gas.

[0053] (7) A control device according to a seventh aspect is the control device described in (5) to (6), wherein the control unit starts transitioning from the safe mode to the second operating mode when the mixing ratio reaches the mixing ratio in the second operating mode or when a predetermined time has elapsed since the mixing ratio in the second operating mode was reached. This allows a stable transition to the second operation mode.

[0054] (8) A control device according to an eighth aspect is a control device according to any one of (1) to (7), wherein the safe modes include a first safe mode in which the set values ​​of the control parameters are relatively close to those of the first operating mode, and a second safe mode in which the set values ​​of the control parameters are relatively close to those of the second operating mode, and when transitioning from the first operating mode to the second operating mode, the control unit transitions from the first operating mode to the first safe mode, from the first safe mode to the second safe mode, and from the second safe mode to the second operating mode. This allows for a more stable transition from the first operation mode to the second operation mode.

[0055] (9) In a control method according to a ninth aspect, when an engine control device transitions the engine operation mode from a first operation mode to a second operation mode, the control device transitions from the first operation mode to a safe mode, which is a common operation mode in which the setting values ​​of control parameters are designed to enable abnormalities to be avoided, and transitions from the safe mode to the second operation mode.

[0056] (10) A program according to a tenth aspect causes a computer to function as a means for transitioning an engine operation mode from a first operation mode to a safe mode, which is a common operation mode in which the setting values ​​of control parameters are designed to enable the avoidance of abnormalities, when the engine operation mode is transitioned from a first operation mode to a second operation mode, and for transitioning from the safe mode to the second operation mode. [Explanation of symbols]

[0057] 1. Engine System 2. Hydrogen mixing device 3. Engine 4 cylinders 5. Piston 6. Combustion chamber 7. Spark plug 8...Antechamber C1, C2, C3... sensors L1: Fuel supply line L2: Air supply line L3: Intake line L4: Secondary fuel line L5...Exhaust line 10. Control device 11. Signal acquisition unit 12... Judgment section 13 Control section 90. Computer 91 Processor 92 Main Memory 93 Storage 94···Interface 100···Gas engine

Claims

1. a control unit that, when transitioning an engine operation mode from a first operation mode to a second operation mode, transitions from the first operation mode to a safe mode, which is a common operation mode designed to enable abnormalities to be avoided, and transitions from the safe mode to the second operation mode; Equipped with the control unit retards the ignition timing of the spark plug by a predetermined amount, then increases the air-fuel ratio by a predetermined amount, then retards the fuel gas supply timing by a predetermined amount, and then reduces the pre-chamber fuel gas flow rate by a predetermined amount, thereby transitioning to the safe mode. Control device.

2. a control unit that, when transitioning an engine operation mode from a first operation mode to a second operation mode, transitions from the first operation mode to a safe mode, which is a common operation mode designed to enable abnormalities to be avoided, and transitions from the safe mode to the second operation mode; Equipped with the control unit increases the flow rate of the pre-chamber fuel gas, advances the fuel gas supply timing, decreases the air-fuel ratio, and advances the ignition timing, thereby transitioning to the second operation mode. Control device.

3. a control unit that, when transitioning an engine operation mode from a first operation mode to a second operation mode, transitions from the first operation mode to a safe mode, which is a common operation mode designed to enable abnormalities to be avoided, and transitions from the safe mode to the second operation mode; Equipped with the control unit increases the flow rate of the pre-chamber fuel gas to the flow rate of the pre-chamber fuel gas in the second operation mode over a predetermined time, advances the fuel gas supply timing to the fuel gas supply timing in the second operation mode over a predetermined time, decreases the air-fuel ratio to the air-fuel ratio in the second operation mode over a predetermined time, and advances the ignition timing to the ignition timing in the second operation mode over a predetermined time, thereby transitioning to the second operation mode.

4. a control unit that, when transitioning an engine operation mode from a first operation mode to a second operation mode, transitions from the first operation mode to a safe mode, which is a common operation mode designed to enable abnormalities to be avoided, and transitions from the safe mode to the second operation mode; Equipped with a control device, wherein the first operating mode is an operating mode using only natural gas as fuel, and the second operating mode is an operating mode using a mixed fuel of natural gas and hydrogen or only hydrogen as fuel.

5. a determination unit that acquires a mixture ratio of hydrogen in the fuel, and determines, when the mixture ratio changes from 0%, that the operation mode will transition from the first operation mode to the second operation mode; The control device of claim 4 further comprising:

6. the control unit starts transition from the safe mode to the second operation mode when the mixing ratio reaches the mixing ratio in the second operation mode or when a predetermined time has elapsed since the mixing ratio in the second operation mode was reached. The control device according to claim 5 .

7. a control unit that, when transitioning an engine operation mode from a first operation mode to a second operation mode, transitions from the first operation mode to a safe mode, which is a common operation mode designed to enable abnormalities to be avoided, and transitions from the safe mode to the second operation mode; Equipped with the safe modes include a first safe mode in which the set values ​​of the control parameters are relatively close to those of the first operation mode, and a second safe mode in which the set values ​​of the control parameters are relatively close to those of the second operation mode, When transitioning from a first operating mode to a second operating mode, the control unit transitions from the first operating mode to the first safe mode, transitions from the first safe mode to the second safe mode, and transitions from the second safe mode to the second operating mode. Control device.

8. a control unit that, when transitioning an engine operation mode from a first operation mode to a second operation mode, transitions from the first operation mode to a safe mode, which is a common operation mode designed to enable abnormalities to be avoided, and transitions from the safe mode to the second operation mode; Equipped with the first operating mode is an operating mode using only hydrogen or a mixed fuel obtained by mixing natural gas and hydrogen as fuel, and the second operating mode is an operating mode using only the mixed fuel having a lower hydrogen mixing ratio than the first operating mode or natural gas as fuel, the control unit transitions to the safe mode by retarding the ignition timing of the spark plug by a predetermined amount, and after transitioning to the safe mode, transitions to the second operation mode by advancing the ignition timing to the ignition timing in the second operation mode over a predetermined time. Control device.

9. The engine control unit When the operation mode of the engine is shifted from a first operation mode to a second operation mode, the operation mode is shifted from the first operation mode to a safe mode which is a common operation mode designed to be able to avoid an abnormality, and then the safe mode is shifted to the second operation mode; When transitioning to the safe mode, the ignition timing of the spark plug is retarded by a predetermined amount, then the air-fuel ratio is increased by a predetermined amount, then the fuel gas supply timing is retarded by a predetermined amount, and then the pre-chamber fuel gas flow rate is reduced by a predetermined amount, thereby transitioning to the safe mode. Control method.

10. Computer, a means for transitioning an engine operation mode from a first operation mode to a second operation mode, the means for transitioning from the first operation mode to a safe mode which is a common operation mode designed to enable abnormalities to be avoided, and from the safe mode to the second operation mode; It functions as When transitioning to the safe mode, the transitioning means retards the ignition timing of the spark plug by a predetermined amount, then increases the air-fuel ratio by a predetermined amount, then retards the fuel gas supply timing by a predetermined amount, and then reduces the pre-chamber fuel gas flow rate by a predetermined amount, thereby transitioning to the safe mode. program.

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