Control device, engine system, control method, and program

Abstract

Provided is a control device having the function of, when the mixing ratio of a mixed fuel of a plurality of fuels is used for control, compensating for the delay from when the mixed fuel is produced to when the mixed fuel reaches a combustion chamber of an engine. The control device controls an engine, in which a mixed fuel generated by mixing a plurality of gases at a mixing point is supplied through piping, on the basis of the mixing ratio of the plurality of gases, and includes: a means for calculating the mixing ratio to compensate for a delay due to the time it takes for the mixed fuel to reach a combustion chamber of the engine from the mixing point; and a means for controlling the engine on the basis of the mixing ratio following the compensation.

Description

Control device, engine system, control method and program

[0001] The present disclosure relates to a control device, an engine system, a control method, and a program. This disclosure claims priority to Japanese Patent Application No. 2023-137072, filed on August 25, 2023, the contents of which are incorporated herein by reference.

[0002] CO ２ As part of efforts to reduce CO2 emissions, a system has been proposed that uses a gas engine powered by a mixture of hydrogen and fuel gases, such as city gas (natural gas). Gas engines that blend and switch between multiple fuels require adjusting the air-fuel ratio and ignition timing based on the fuel's properties and calorie content, as well as adjusting the fuel density and calorie information used for control. When using a mixture of multiple fuels, a valve is often installed at the fuel mixing point (known as the mixing point) to control the desired mixture ratio, and this mixture ratio is then used to control the engine. In such engines, the mixture ratio needs to be adjusted or switched on or off. However, if the distance from the mixing point to the combustion chamber in the engine cylinder is long, the mixture ratio at the mixing point may differ from the actual mixture ratio in the combustion chamber. For example, in situations where the fuel mixture ratio must be switched instantaneously due to a sudden change in load or the detection of an engine abnormality, the difference between the mixture ratio at the mixing point and the combustion chamber may become significant.

[0003] Patent Document 1 discloses a control method that detects abnormal combustion conditions using the in-cylinder pressure of a hydrogen-fuel engine and resolves the abnormal condition by appropriately controlling the hydrogen mixture ratio. However, Patent Document 1 does not anticipate a premixing method in which there is a distance between the mixing point and the combustion chamber, and does not disclose a mechanism for compensating for the difference between the mixture ratio at the mixing point and the actual mixture ratio in the combustion chamber - in other words, the time (delay) until the mixed fuel, controlled to the desired mixture ratio at the mixing point, reaches the combustion chamber.

[0004] International Publication No. 2022 / 259771

[0005] In an engine that uses a mixed fuel in which a plurality of fuels are mixed, there is a need for control that takes into account the delay between when the fuel mixed at a desired mixture ratio travels from the mixing point to the combustion chamber.

[0006] The present disclosure provides a control device, an engine system, a control method, and a program that can solve the above-mentioned problems.

[0007] According to one aspect of the present disclosure, a control device controls an engine to which a mixed fuel produced by mixing a plurality of gases at a mixing point is supplied through a pipe, based on a mixing ratio of the plurality of gases, and includes: means for calculating the mixing ratio at the mixing point by compensating for a delay in the mixed fuel reaching the combustion chamber of the engine from the mixing point; and means for controlling the engine based on the mixing ratio after the compensation.

[0008] According to one aspect of the present disclosure, an engine system includes an engine, a fuel mixing device that mixes a plurality of gases at a mixing point, piping that connects the mixing point to the engine, and the above-described control device.

[0009] According to one aspect of the present disclosure, a control method is a control method for controlling an engine to which a mixed fuel produced by mixing a plurality of gases at a mixing point is supplied through a pipe, based on a mixing ratio of the plurality of gases, and includes the steps of: calculating the mixing ratio at the mixing point by compensating for a delay in the mixed fuel reaching a combustion chamber of the engine from the mixing point; and controlling the engine based on the compensated mixing ratio.

[0010] According to one aspect of the present disclosure, the program causes a computer of a control device that controls an engine to which a mixed fuel generated by mixing a plurality of gases at a mixing point is supplied through a pipe based on a mixing ratio of the plurality of gases, to execute the following steps: calculating the mixing ratio at the mixing point by compensating for a delay until the mixed fuel reaches a combustion chamber of the engine from the mixing point; and controlling the engine based on the compensated mixing ratio.

[0011] The above-described control device, engine system, control method, and program can compensate for the delay between when the fuel mixture is produced and when it is supplied to the combustion chamber, thereby enabling stable engine operation.

[0012] FIG. 1 is a block diagram illustrating an example of an engine system according to an embodiment. FIG. 2 is a diagram illustrating a delay compensation process according to an embodiment. FIG. 3 is a diagram illustrating an example of setting dead time and the like according to a flow rate range according to an embodiment. FIG. 4 is a flowchart illustrating an example of engine control according to an embodiment. FIG. 5 is a flowchart illustrating an example of switching control between presence and absence of mixing according to an embodiment. FIG. 6 is a schematic diagram illustrating an example of a hardware configuration of a controller according to an embodiment.

[0013] <Embodiment> The configuration and control of an engine system 1 according to the present disclosure will be described below with reference to Figures 1 to 6. Figure 1 is a block diagram showing an example of an engine system according to an embodiment. The engine system 1 includes a hydrogen mixing device 2, an engine 3, a generator 4, a circuit breaker 5, a hydrogen mixing device controller 20 that controls the hydrogen mixing device 2, an engine controller 30 that controls the engine 3, and a generator controller 40 that controls the generator 4, etc.

[0014] The hydrogen mixing device 2 mixes hydrogen with fuel gas, such as city gas (natural gas), to produce a mixed fuel and supplies the produced mixed fuel to the engine 3. The proportion of hydrogen in the mixed fuel is called the mixture ratio. The mixture ratio is controlled between 0 and several tens of percent. For example, when the engine 3 starts and enters a stable operating state, the mixture ratio is gradually increased from 0% until it reaches a predetermined value, at which point the mixture ratio is maintained. If a sudden change in load or an abnormality in the engine 3 is detected, the mixture ratio is immediately reduced to 0%. When the mixture ratio is gradually increased to a predetermined value, the change in the mixture ratio per unit time is small, so the delay in the mixed fuel reaching the combustion chamber is not a significant issue. However, when the mixture ratio is changed significantly in a short period of time (e.g., when the mixture ratio is immediately reduced to 0%), the mixture ratio at the mixing point and the combustion chamber is likely to deviate. Therefore, using the control value of the mixture ratio (the mixture ratio at the mixing point) to perform control may result in erroneous control based on a mixture ratio that differs from the actual value. Therefore, in this embodiment, the actual mixture ratio in the combustion chamber is estimated from the mixture ratio of the mixed fuel produced by the hydrogen mixer 2, and the estimated value is used to control the engine 3.

[0015] The hydrogen mixing device 2 includes a pipe 2A to which fuel gas (hereinafter referred to as city gas) is supplied, a pipe 2B to which hydrogen gas is supplied, and a pipe 2C to which the mixed fuel is supplied. The pipes 2A and 2B are connected to the pipe 2C at a mixing point 2D. A flow control valve 2a is provided in the pipe 2A, and a flow control valve 2b is provided in the pipe 2B. Pressure gauges (not shown) are provided in the pipes 2A and 2B, and the hydrogen mixing device controller 20 controls the apertures of the flow control valves 2a and 2b based on the flow rates of hydrogen gas and city gas calculated from the measured pressures of the pipes 2A and 2B, thereby controlling the mixing ratio at the mixing point 2D to a desired value. The mixing ratio value may be preset in the hydrogen mixing device controller 20 or may be instructed by the engine controller 30 or the generator controller 40.

[0016] The engine 3 is a gas engine that uses city gas as fuel. It generates an air-fuel mixture by mixing the mixed fuel supplied from the hydrogen mixing device 2 with intake air (air) supplied through a pipe 3a, and then burns the generated air-fuel mixture to rotate and drive the output shaft 3b. The engine controller 30 operates the engine 3 primarily by performing combustion control and air-fuel ratio control. The combustion control involves feedback control to maintain the engine 3's rotation speed and load constant. The air-fuel ratio control involves feedback control to maintain a constant air-fuel ratio in the combustion chamber of the engine 3 by controlling a throttle valve (not shown) or the like provided in the piping system for the air-fuel mixture flowing into the combustion chamber. The configuration of the engine 3, combustion control, and air-fuel ratio control are well known, and therefore detailed description thereof will be omitted. The function of the engine controller 30 related to the delay compensation process of this embodiment will be described later.

[0017] The generator 4 is connected to the engine 3 via the output shaft 3b, and generates electricity using the rotational driving force transmitted from the output shaft 3b. The generator 4 is connected to an electric power system (not shown) via a circuit breaker 5. The electric power generated by the generator 4 is supplied to a load 6 through the electric power system by opening and closing the circuit breaker 5. A generator controller 40 controls the generator 4, the circuit breaker 5, and auxiliary equipment (not shown).

[0018] The hydrogen mixing device controller 20, the engine controller 30, and the generator controller 40 are connected to one another via a network such as a LAN and signal lines. The control status of the engine system 1 is transmitted and received via the network, and fault information (fault contact signals) and the like are transmitted and received via signal lines, and this information is shared among the three controllers 20, 30, and 40. For example, the hydrogen mixing device controller 20 transmits the hydrogen mixing ratio at the mixing point 2D to the engine controller 30. The engine controller 30 transmits to the hydrogen mixing device controller 20 and the generator controller 40 the result of a determination as to whether or not multi-fuel combustion control (operation of the engine 3 using a fuel mixture containing hydrogen) is possible. A signal instructing the start of multi-fuel combustion is transmitted from the hydrogen mixing device controller 20 or the generator controller 40 to the engine controller 30. The generator controller 40 detects the magnitude of the load 6 and transmits a load signal indicating the magnitude of the load 6 to the engine controller 30.

[0019] The engine controller 30 includes a signal acquisition unit 31, a multi-fuel combustion feasibility determination unit 32, and a control unit 33. The signal acquisition unit 31 acquires a load signal indicating the magnitude of the load 6 from the generator controller 40. The signal acquisition unit 31 makes decisions such as load shedding and load application based on the load signal. The signal acquisition unit 31 acquires the mixing ratio at the mixing point 2D from the hydrogen mixing device controller 20. The signal acquisition unit 31 acquires an instruction signal to start multi-fuel combustion control from the hydrogen mixing device controller 20 or the generator controller 40.

[0020] The multi-fuel combustion feasibility determination unit 32 determines whether multi-fuel combustion control, i.e., whether the engine 3 is capable of operating on a mixed fuel obtained by mixing hydrogen with fuel gas, is possible. For example, the multi-fuel combustion feasibility determination unit 32 determines that multi-fuel combustion control is possible when the magnitude of the load 6 is equal to or greater than a predetermined reference value or when the engine 3 is considered to be in a stable operating state. For example, the multi-fuel combustion feasibility determination unit 32 determines that multi-fuel combustion control is impossible when it detects a sudden change in the load or an abnormal state. The multi-fuel combustion feasibility determination unit 32 transmits the determination result to the hydrogen mixing device controller 20 and the generator controller 40. If it is determined that multi-fuel combustion control is possible, for example, an operator or the like instructs the hydrogen mixing device controller 20 or the generator controller 40 to start multi-fuel combustion control. Based on this instruction, the hydrogen mixing device controller 20 starts producing a mixed fuel. If it is determined that multi-fuel combustion control is impossible, the hydrogen mixing device controller 20 fully closes the flow control valve 2b and fully opens the flow control valve 2a, thereby supplying city gas with a 0% mixture ratio to the engine 3.

[0021] The control unit 33 controls the engine 3. For example, the control unit 33 controls the air-fuel ratio by targeting an air-fuel ratio corresponding to the hydrogen mixing ratio. For example, the control unit 33 has a table that associates mixing ratios with air-fuel ratios, and calculates the air-fuel ratio corresponding to the mixing ratio based on this table and the mixing ratio acquired from the hydrogen mixing device controller 20, and performs feedback control so that the air-fuel ratio in the combustion chamber becomes the calculated air-fuel ratio. At this time, the control unit 33 compensates for the delay until the mixed fuel, controlled to the desired mixing ratio, reaches the combustion chamber of the engine 3 from the mixing point 2D, and calculates the target air-fuel ratio based on the compensated mixing ratio. FIG. 2 shows an example of the delay compensation process in this embodiment. The control unit 33 acquires the mixing ratio r(t) at the mixing point 2D at time t from the hydrogen mixing device controller 20 via the signal acquisition unit 31. The control unit 33 calculates the target air-fuel ratio using a transfer function G(s)=e shown in the block diagram of FIG. 2. －Lｓ The mixing ratio rc(t) after delay compensation is calculated by / Tb·s+1. Here, L is the dead time, and Tb is the time constant of the first-order delay. The dead time L can be expressed as L=V / Q. The time constant Tb of the first-order delay can be expressed as Tb=1 / (PV / RT·Q·σ). V is the volume (m３ ), Q is the flow rate of the mixed fuel (m ３ / sec), P is the pressure of the mixed fuel (Pa), R is the gas constant, and σ is the density of the mixed fuel (kg / m ３ ), T is the temperature (°C) of the mixed fuel, and s is the Laplace operator. For example, the delay with which the mixed fuel with the mixing ratio r(t0) is supplied to the combustion chamber can be determined from the mixing ratio r(t0) at the mixing point 2D at time t0 using the transfer function G(s) described above. The mixing ratio of the mixed fuel that reaches the combustion chamber at each time can be estimated by constantly calculating the delay-compensated mixing ratio rc(t) from the current mixing ratio r(t) using the transfer function G(s). This allows the control unit 33 to control the engine 3 using the mixing ratio rc(t0) of the mixed fuel that was supplied to the pipe 2C from the hydrogen mixing device 2 a little earlier and reaches the combustion chamber at time t0, rather than the mixing ratio r(t0) of the mixed fuel generated by the hydrogen mixing device 2 at time t0.

[0022] The delay due to the piping from the mixing point 2D to the cylinder of the engine 3 is considered to be only the dead time L (i.e., Tb = 0), and the first-order lag time constant Tb is used for adjustment. When the first-order lag time constant Tb is used, the dead time L is also taken into consideration to adjust the delay so that it does not become too large. The control unit 33 may acquire measured values ​​of the mixed fuel flow rate Q, mixed fuel pressure P, mixed fuel density σ, mixed fuel temperature T, etc., calculate the first-order lag time constant Tb and the dead time L each time, and calculate the mixture ratio after delay compensation using the transfer function G(s). Alternatively, values ​​such as the flow rate Q and density σ for a frequently used mixed fuel flow rate range or a flow rate range when a mixing ratio switch occurs may be measured or calculated in advance, and the first-order lag time constant Tb and the dead time L may be calculated using these values ​​and set in the control unit 33. The mixture ratio after delay compensation may then be calculated using Tb and L for the corresponding flow rate range depending on the operating state and load 6 of the engine 3. 3 shows an example of the first-order lag time constant Tb and dead time L corresponding to the flow rate range. For example, the control unit 33 may have a table as shown in FIG. 3 , determine which flow rate range the mixed fuel flow rate belongs to based on the operating state of the engine 3 and the magnitude of the load 6 at that time (for example, prepare a table that defines the correspondence between the operating state of the engine 3 and the flow rate range), obtain the first-order lag time constant Tb and dead time L corresponding to the mixed fuel flow rate by referring to the table in FIG. 3 , and calculate the mixing ratio after delay compensation using the transfer function G(s). Alternatively, a table that defines the values ​​of the first-order lag time constant Tb and dead time L for each operating state of the engine 3 and the magnitude of the load 6 may be set in the control unit 33, and the mixing ratio after delay compensation may be calculated based on this table and the operating state of the engine 3 at that time.

[0023] (Engine Control Operation Taking Mixing Ratio Supply Delay into Account) Next, with reference to FIG. 4, the engine control process taking mixing ratio supply delay into account according to this embodiment will be described. FIG. 4 is a flowchart illustrating an example of engine control according to this embodiment. The hydrogen mixing device controller 20 controls the flow control valves 2a and 2b so that the hydrogen mixing ratio at the mixing point 2D becomes a desired value. The hydrogen mixing device controller 20 transmits the controlled mixing ratio value to the engine controller 30. In the engine controller 30, the signal acquisition unit 31 acquires the mixing ratio value (step S1). The signal acquisition unit 31 outputs the acquired mixing ratio value to the control unit 33. The control unit 33 calculates the mixing ratio after delay compensation processing using the transfer function (G(s)) illustrated in FIG. 2 (step S2). The control unit 33 stores the calculated mixing ratio after delay compensation processing. By constantly executing steps S1 and S2 while the engine 3 is operating, the control unit 33 stores the time-series mixing ratio after delay compensation processing. Next, the control unit 33 controls the engine 3 based on the mixture ratio in the combustion chamber, rather than the mixture point 2D acquired from the hydrogen mixing device controller 20 (step S3). The control unit 33 determines the mixture ratio of the mixed fuel in the combustion chamber at the current time from the mixture ratios after the time-series delay compensation process calculated in the process of step S2, and performs control according to the determined mixture ratio.

[0024] (Effect) Conventional control does not take into account the time it takes for the mixed fuel to reach the cylinder from the mixing point 2D. Therefore, in situations where the mixture ratio suddenly changes, a discrepancy occurs between the mixture ratio at the mixing point 2D and the mixture ratio in the combustion chamber, and if engine control is performed using the mixture ratio control value (the mixture ratio at the mixing point 2D), the operating state of the engine 3 may become unstable. In contrast, according to the present embodiment, the delay in the arrival of the mixed fuel is taken into account and control is performed according to the actual mixture ratio in the combustion chamber, thereby enabling stable operation of the engine 3.

[0025] Next, we will explain how to change the mixture ratio and switch between mixing and non-mixing. To ensure stable operation of the engine 3, the mixed fuel feasibility determination unit 32 determines that mixed fuel combustion is possible only when stable operation is possible using mixed fuel, and otherwise selects operation using only city gas.

[0026] 5 is a flowchart showing an example of switching control of whether or not to mix fuels according to the embodiment. The multi-fuel combustion possibility determination unit 32 determines whether or not multi-fuel combustion control is possible based on the state of the load 6 or the engine 3, and whether or not there is an abnormality (step S11). The multi-fuel combustion possibility determination unit 32 determines whether to perform multi-fuel combustion control or to stop mixing based on whether stable operation is possible. For example, if stable operation is possible even if the mixing ratio is increased, the CO ２ If stable operation is difficult under mixed combustion control, the mixed combustion feasibility determination unit 32 determines whether to change the mixed combustion ratio or to stop the mixing, based on the following criteria (1) to (4).

[0027] (1) Determination Based on Load To ensure stable combustion, for example, the multi-fuel combustion feasibility determination unit 32 determines to perform multi-fuel combustion control when the magnitude of the load 6 acquired by the signal acquisition unit 31 is equal to or greater than a certain value. For example, the multi-fuel combustion feasibility determination unit 32 may determine that multi-fuel combustion control is possible when the magnitude of the load 6 is equal to or greater than a predetermined load, and may determine to stop multi-fuel combustion control when the magnitude of the load 6 is less than the predetermined load. Alternatively, the multi-fuel combustion feasibility determination unit 32 may have map information that associates the load size with the fuel mixture ratio, and may determine whether to perform multi-fuel combustion control or whether to change the fuel mixture ratio based on the load 6 size and the map information.

[0028] (2) Determination Based on Other Engine Conditions The multi-fuel combustion feasibility determination unit 32 may determine that the engine 3 is warmed up if the temperatures of the lubricating oil, cooling water, etc. are equal to or higher than a predetermined threshold, and may determine that the engine 3 is in a stable operating state if the engine 3 is warmed up and that fuels should be mixed (multi-fuel control is possible), and may determine that fuel mixing should be stopped if the engine 3 is not in that state. For example, the multi-fuel combustion feasibility determination unit 32 may determine that the operating state is stable after a certain period of time has passed since the start of the engine 3 and that multi-fuel control is possible.

[0029] (3) Determination Based on Abnormal Condition The multi-fuel combustion possibility determination unit 32 determines to immediately stop the fuel-fuel mixture upon detecting an abnormality in the engine 3.

[0030] (4) Load Shedding, Load Application When the signal acquisition unit 31 detects load shedding, the multi-fuel combustion feasibility determination unit 32 determines that mixing should be immediately stopped. Load shedding is detected by detecting an "open" in the circuit breaker 5 or a sudden drop in the load. When the signal acquisition unit 31 detects load application, the multi-fuel combustion feasibility determination unit 32 determines that mixing should be immediately stopped. Load application is detected by detecting a "close" in the circuit breaker 5 or a sudden increase in the load.

[0031] If the hybrid fuel-mixing capability determination unit 32 determines that hybrid fuel-mixing control is possible based on the above criteria (1) to (4) (Step S11; Yes), the hybrid fuel-mixing capability determination unit 32 notifies the hydrogen mixing device controller 20 that hybrid fuel-mixing control is possible (Step S12). When this signal is transmitted and the operator, who has confirmed that hybrid fuel-mixing control is possible, issues a command to start hybrid fuel-mixing control, the hydrogen mixing device controller 20 increases the hydrogen mixing ratio to a predetermined ratio, for example, at a predetermined rate. For example, if the hydrogen mixing ratio is to be continuously changed based on map information of the load and the hydrogen mixing ratio, the hybrid fuel-mixing capability determination unit 32 may determine the hydrogen mixing ratio according to the load 6 based on the magnitude of the load 6 and the map information, and notify the hydrogen mixing device controller 20 of the determined hydrogen mixing ratio. The hydrogen mixing device controller 20 then controls the flow control valves 2a and 2b to change the hydrogen mixing ratio to the determined hydrogen mixing ratio at a predetermined rate. After changing the hydrogen mixing ratio, the hydrogen mixing device controller 20 notifies the engine controller 30 of the changed hydrogen mixing ratio.

[0032] If the multi-fuel combustion possibility determination unit 32 determines that multi-fuel combustion control is not possible (step S11; No), the multi-fuel combustion possibility determination unit 32 notifies the hydrogen mixing device controller 20 that multi-fuel combustion control is not possible (step S13). For example, if load shedding is detected during multi-fuel combustion control, the multi-fuel combustion possibility determination unit 32 sends a signal to stop mixing. The hydrogen mixing device controller 20 immediately reduces the hydrogen mixing ratio to 0%. After changing the mixing ratio, the hydrogen mixing device controller 20 notifies the engine controller 30 of the changed mixing ratio. If fuel mixing was not originally performed, the hydrogen mixing device controller 20 does not change the mixing ratio and supplies only city gas to the engine 3.

[0033] In the engine controller 30, the signal acquisition unit 31 acquires the mixing ratio from the hydrogen mixing device controller 20, and the control unit 33 controls the engine 3 (step S14). The process of step S14 is as described with reference to FIG. 4. The control unit 33 calculates the mixing ratio taking delay into account and controls the engine 3 using the calculated mixing ratio after delay compensation. In this case, the control unit 33 may calculate the mixing ratio after delay compensation using a first-order lag time constant Tb and a dead time L corresponding to the flow rate range. For example, the control unit 33 has a table in which the first-order lag time constant Tb and the dead time L are set for each flow rate range, as shown in FIG. 3, and determines L and Tb based on this table and the flow rate Q of the mixed fuel. The control unit 33 then calculates the mixing ratio after delay compensation using the determined L and TB and the transfer function of FIG. 2. The control unit 33 then controls the engine 3 using the mixing ratio after delay compensation.

[0034] Next, the control unit 33 determines whether or not to terminate the operation of the engine 3 (step S15). For example, when a command to stop the engine 3 is input by the user, the control unit 33 determines to terminate the operation of the engine 3 (step S15; Yes) and terminates the processing of the flowchart in Fig. 5. If the operation is not to be terminated (step S15; No), the processing from step S11 is repeatedly executed.

[0035] 5 , the mixture ratio is changed depending on the operating state of the engine 3, whether or not there is an abnormality, whether or not there is a sudden load change, etc., thereby enabling stable operation without stopping the engine 3. Since the mixture ratio in the combustion chamber can be used for control even in situations where the mixture ratio at the mixing point D2 is likely to differ from the mixture ratio in the combustion chamber, such as when mixing is immediately stopped, the mixture ratio in the combustion chamber can be used for control, enabling stable operation of the engine 3.

[0036] In the above embodiment, city gas and hydrogen gas are mixed, but the types of gases to be mixed are not limited to these. Three or more types of gases may be mixed.

[0037] 6 is a schematic block diagram showing the hardware configuration of a controller according to an embodiment. The computer 90 includes a processor 91, a main memory 92, a storage 93, and an interface 94. The hydrogen mixing device controller 20, the engine controller 30, and the generator controller 40 are implemented in the computer 90. The operations 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 allocates storage areas in the main memory 92 corresponding to 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.

[0038] 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 another embodiment, 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.

[0039] 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 internal media directly connected to the bus of computer 90, or may be external media connected to computer 90 via interface 94 or a communication line. When this program is distributed to computer 90 via a communication line, computer 90 that receives 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.

[0040] The program may be a program for realizing 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.

[0041] 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.

[0042] <Additional Notes> The control device, engine system, control method, and program described in each embodiment can be understood, for example, as follows.

[0043] (1) A control device according to a first aspect controls an engine to which a mixed fuel produced by mixing a plurality of gases at a mixing point is supplied through a pipe, based on a mixture ratio of the plurality of gases, and includes: means for calculating the mixture ratio at the mixing point by compensating for a delay between the mixed fuel's arrival at the mixing point and its arrival at a combustion chamber of the engine (controller 33, step S2); and means for controlling the engine based on the compensated mixture ratio (controller 33, step S3). This compensates for the delay between the production of the mixed fuel and its supply to the combustion chamber, enabling stable engine operation.

[0044] (2) A control device according to a second aspect is the control device of (1), wherein the means for calculating the mixing ratio is a transfer function G(s)=e where L is a dead time, Tb is a first-order lag time constant, L=V / Q, Tb=1 / (PV / RT·Q·σ), V is a volume of the piping from the mixing point to the cylinder of the engine, Q is a flow rate of the mixed fuel, P is a pressure of the mixed fuel, R is a gas constant, σ is a density of the mixed fuel, T is a temperature of the mixed fuel, and s is a Laplace operator. －LｓThe mixing ratio at the mixing point is input to / Tb·s+1 to calculate the mixing ratio with the delay compensated for. This makes it possible to compensate for the delay in the mixing ratio.

[0045] (3) A control device according to a third aspect is the control device of (2), wherein the means for calculating the mixing ratio has a table that associates the flow rate of the mixed fuel with the L and the Tb, determines the L and the Tb using the flow rate of the mixed fuel flowing through the pipe and the table, and calculates the delay-compensated mixing ratio according to the flow rate of the mixed fuel flowing through the pipe using the determined L and Tb and the transfer function G(s). This reduces the calculation load when calculating the delay-compensated mixing ratio.

[0046] (4) A control device according to a fourth aspect is the control device of (1) to (3), further comprising a means for determining whether or not to change the mixture ratio (multi-fuel combustion possibility determination unit 32, step S11), wherein the determination means determines to mix the multiple gases when the magnitude of the engine load is equal to or greater than a predetermined threshold, and determines not to mix the multiple gases when the magnitude of the engine load is less than the threshold. By allowing mixing only when the operating load is equal to or greater than a certain level, stable engine operation can be achieved.

[0047] (5) A control device according to a fifth aspect is the control device of (1) to (4), further comprising a means for determining whether to change the mixing ratio, wherein the means for determining whether to mix the plurality of gases when the engine is in a stable operating state, and whether to not mix the plurality of gases when the engine is not in a stable operating state. By allowing mixing only when the engine is in a stable operating state, stable engine operation can be achieved.

[0048] (6) A control device according to a sixth aspect is the control device of any one of (1) to (5), further comprising a means for determining whether to change the mixing ratio, wherein the means for determining determines to stop mixing the plurality of gases when an abnormality in the engine is detected. By quickly stopping mixing when an abnormality in the engine is detected, stable engine operation can be achieved.

[0049] (7) A seventh aspect of the present invention is a control device according to any one of (1) to (6), further comprising a means for determining a change in the mixing ratio, wherein the means for determining determines to stop mixing the plurality of gases when a load is detected as being cut off or added. By stopping mixing when the load suddenly changes, stable engine operation can be achieved.

[0050] (8) An engine system according to an eighth aspect includes an engine, a fuel mixing device that mixes multiple gases at a mixing point, piping that connects the mixing point to the engine, and a control device described in any one of (1) to (7).

[0051] (9) A control method according to a ninth aspect is a control method for controlling an engine to which a mixed fuel produced by mixing a plurality of gases at a mixing point is supplied through a pipe, based on a mixing ratio of the plurality of gases, and includes the steps of: calculating the mixing ratio at the mixing point by compensating for a delay in the mixed fuel reaching a combustion chamber of the engine from the mixing point; and controlling the engine based on the mixing ratio after the compensation.

[0052] (10) A program according to a tenth aspect causes a computer of a control device that controls an engine to which a mixed fuel produced by mixing a plurality of gases at a mixing point is supplied through a pipe based on a mixing ratio of the plurality of gases, to execute the following steps: calculating the mixing ratio at the mixing point by compensating for a delay in the mixed fuel reaching the combustion chamber of the engine from the mixing point; and controlling the engine based on the mixing ratio after the compensation.

[0053] The above-described control device, engine system, control method, and program can compensate for the delay between when the fuel mixture is produced and when it is supplied to the combustion chamber, thereby enabling stable engine operation.

[0054] DESCRIPTION OF SYMBOLS 1 Engine system 2 Hydrogen mixing device 3 Engine 4 Generator 5 Circuit breaker 6 Load 20 Hydrogen mixing device controller 30 Engine controller 31 Signal acquisition unit 32 Multi-firing possibility determination unit 33 Control unit 40 Generator controller 90 Computer 91 Processor 92 Main memory 93 Storage 94 Interface

Claims

1. A control device that controls an engine to which mixed fuel produced by mixing a plurality of gases at a mixing point is supplied through a pipe, based on a mixing ratio of the plurality of gases, the control device comprising: a means for calculating a mixing ratio obtained by compensating for a delay in the mixed fuel reaching a combustion chamber of the engine from the mixing point, with respect to the mixing ratio at the mixing point; and a means for controlling the engine based on the mixing ratio after compensation.

2. The means for calculating the mixture ratio is expressed by the transfer function G(s)=e where L is dead time, Tb is a first-order time lag constant, L=V / Q, Tb=1 / (PV / RT·Q·σ), V is the volume of the piping from the mixing point to the engine cylinder, Q is the flow rate of the mixed fuel, P is the pressure of the mixed fuel, R is a gas constant, σ is the density of the mixed fuel, T is the temperature of the mixed fuel, and s is a Laplace operator. －Lｓ The control device according to claim 1 , wherein the mixing ratio in which the delay has been compensated for is calculated by inputting the mixing ratio at the mixing point to / Tb·s+1.

3. The control device according to claim 2, wherein the means for calculating the mixing ratio has a table correlating the flow rate of the mixed fuel with L and Tb, determines L and Tb using the flow rate of the mixed fuel flowing through the piping and the table, and calculates the mixing ratio with the delay compensated for according to the flow rate of the mixed fuel flowing through the piping using the determined L, Tb and transfer function G(s).

4. The control device according to claim 1 or claim 2, further comprising a means for determining a change in the mixing ratio, the means for determining determining that the multiple gases should be mixed when the magnitude of the engine load is equal to or greater than a predetermined threshold, and that the multiple gases should not be mixed when the magnitude of the engine load is less than the threshold.

5. The control device according to claim 1 or claim 2, further comprising a means for determining a change in the mixing ratio, the means for determining determining that the plurality of gases should be mixed when the engine is in a stable operating state, and that the plurality of gases should not be mixed when the engine is not in a stable operating state.

6. The control device according to claim 1 or 2, further comprising a means for determining a change in the mixing ratio, wherein the means for determining determines to stop mixing the plurality of gases when an abnormality is detected in the engine.

7. The control device according to claim 1 or 2, further comprising a means for determining a change in the mixing ratio, wherein the means for determining determines to stop mixing of the plurality of gases when a load interruption or load introduction is detected.

8. An engine system comprising: an engine; a mixing device that mixes a plurality of gases at a mixing point; piping that connects the mixing point and the engine; and the control device according to claim 1 or 2.

9. A control method for controlling an engine to which mixed fuel produced by mixing a plurality of gases at a mixing point is supplied through a pipe, based on a mixing ratio of the plurality of gases, the control method comprising: a step of calculating a mixing ratio at the mixing point by compensating for a delay in the mixed fuel reaching a combustion chamber of the engine from the mixing point; and a step of controlling the engine based on the mixing ratio after the compensation.

10. A program that causes a computer of a control device that controls an engine to which mixed fuel produced by mixing a plurality of gases at a mixing point is supplied through a pipe based on the mixing ratio of the plurality of gases, to execute the following steps: calculating a mixing ratio at the mixing point by compensating for a delay in the mixed fuel reaching the combustion chamber of the engine from the mixing point; and controlling the engine based on the mixing ratio after compensation.

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