Internal combustion engine startup control system

Abstract

This invention provides an internal combustion engine startup control system that has a safety function to prevent the engine from starting with a gas different from the target gas for the operating mode. [Solution] The starting control system for an internal combustion engine includes: a first fuel gas supply line for supplying a first fuel gas belonging to a predetermined first pressure range to the internal combustion engine; a second fuel gas supply line for supplying a second fuel gas belonging to a predetermined second pressure range that does not overlap with the first pressure range to the internal combustion engine, wherein the second fuel gas supply line is a shared line with the first fuel gas supply line on the side of the merging point that is closer to the internal combustion engine; a supply gas pressure acquisition device for acquiring the pressure of the gas flowing through the shared line; and a control device that, in an operating mode using the first fuel gas as fuel, does not start the internal combustion engine if the pressure of the gas acquired by the supply gas pressure acquisition device does not belong to the first pressure range.

Description

Technical Field

[0001] The present disclosure relates to a starting control system for an internal combustion engine.

Background Art

[0002] In a hydrogen engine (internal combustion engine) that uses hydrogen gas as fuel, operation is mainly performed in an operation mode using hydrogen gas as fuel. In such a hydrogen engine (internal combustion engine), after performing work for maintenance or part replacement, a test run using city gas as fuel may be performed before performing operation using hydrogen gas as fuel. Hydrogen gas has a wider flammable range than city gas, and when hydrogen gas leaks from the fuel system, fuel chamber, etc., the risk of causing a fire is higher than when city gas leaks. Therefore, city gas may be used as fuel for the first test run after work on the hydrogen engine (internal combustion engine).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] During the above test run, it is necessary to switch the fuel gas supply system from the hydrogen gas supply system to the city gas supply system. If the type of gas supplied as fuel to the internal combustion engine can be determined, it is desirable to interlock so that the internal combustion engine cannot be started even if the switching of the fuel gas supply system is neglected during the above test run.

[0005] Patent Document 1 discloses a method for calculating the gas constant of a gaseous fuel to be filled into a fuel tank as a means for determining which gaseous fuel is introduced into an internal combustion engine. The method disclosed in Patent Document 1 requires a fuel tank used for determining the gaseous fuel to be installed on the gaseous fuel supply system, which may incur additional costs. Furthermore, the method disclosed in Patent Document 1 may require the fuel to be drained from the fuel tank and then refilled with gaseous fuel.

[0006] In view of the circumstances described above, at least one embodiment of this disclosure aims to provide an internal combustion engine startup control system having a safety function that prevents the internal combustion engine from being started with a gas different from the target gas of the operating mode. [Means for solving the problem]

[0007] The starting control system for an internal combustion engine according to at least one embodiment of the present disclosure is: A first fuel gas supply line for supplying a first fuel gas belonging to a predetermined first pressure range to an internal combustion engine, A second fuel gas supply line for supplying a second fuel gas belonging to a predetermined second pressure range that does not overlap with the first pressure range to the internal combustion engine, wherein the second fuel gas supply line is a shared line with the first fuel gas supply line on the side of the internal combustion engine that is closer to the confluence of the first fuel gas supply line and the second fuel gas supply line, A supply gas pressure acquisition device configured to acquire the pressure of the gas flowing through the aforementioned shared line, The control device for controlling the starting of the internal combustion engine is configured to prevent the starting of the internal combustion engine if, in an operating mode using the first fuel gas, the pressure of the gas acquired by the supply gas pressure acquisition device does not fall within the first pressure range. [Effects of the Invention]

[0008] According to at least one embodiment of the present disclosure, an internal combustion engine startup control system is provided that has a safety function to prevent the internal combustion engine from being started with a gas different from the target gas of the operating mode. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram illustrating the configuration of a startup control system for an internal combustion engine according to one embodiment of the present disclosure. [Figure 2] This is a schematic diagram illustrating the configuration of a startup control system for an internal combustion engine according to one embodiment of the present disclosure. [Figure 3] This is a schematic diagram illustrating the configuration of a startup control system for an internal combustion engine according to one embodiment of the present disclosure. [Figure 4] This is an explanatory diagram illustrating the pressure range of the gas supplied to an internal combustion engine in one embodiment of the present disclosure. [Figure 5] This is a schematic diagram illustrating the configuration of a control device in one embodiment of the present disclosure. [Modes for carrying out the invention]

[0010] Hereinafter, several embodiments of this disclosure will be described with reference to the attached drawings. However, the dimensions, materials, shapes, relative arrangements, etc., of the components described or shown in the drawings as embodiments are not intended to limit the scope of this disclosure, but are merely illustrative examples.

[0011] (Startup control system for internal combustion engines) Figures 1 to 3 are schematic diagrams illustrating the configuration of a starting control system 1 for an internal combustion engine 2 according to one embodiment of the present disclosure. The starting control system 1 for an internal combustion engine 2 according to several embodiments is for controlling the starting of the internal combustion engine 2. As shown in Figures 1 to 3, the starting control system 1 comprises a first fuel gas supply line 3, a second fuel gas supply line 4, a supply gas pressure acquisition device 6, and a control device 7.

[0012] (Internal combustion engine) The internal combustion engine 2 is configured to be driven by burning a gaseous fuel (combustible gas). In the embodiments shown in Figures 1 to 3, the internal combustion engine 2 has at least one (multiple in the illustrated example) cylinder 21 and a piston 22 housed inside the cylinder 21. Each of the multiple cylinders 21 has a combustion chamber 23 for burning the gaseous fuel (combustible gas). The combustion chamber 23 is formed between the cylinder 21 and the piston 22 housed inside the cylinder 21. The internal combustion engine 2 is configured to burn gaseous fuel, or a mixed gas of gaseous fuel and a combustion gas (e.g., air), in each of the combustion chambers 23 of the multiple cylinders 21.

[0013] (First fuel gas supply line, second fuel gas supply line) The first fuel gas supply line 3 forms a passage for guiding a gaseous first fuel gas belonging to a predetermined first pressure range to the internal combustion engine 2, and is not limited to piping. The second fuel gas supply line 4 forms a passage for guiding a gaseous second fuel gas belonging to a predetermined second pressure range that does not overlap with the first pressure range to the internal combustion engine 2, and is not limited to piping. The second fuel gas is a different type of gas from the first fuel gas.

[0014] In the following embodiments, we will explain using the example where the first fuel gas is city gas mainly composed of natural gas and the second fuel gas is hydrogen gas, but the first and second fuel gases are not limited to these gases. In a hydrogen engine (internal combustion engine 2) that uses hydrogen gas as fuel, operation is mainly performed using hydrogen gas (second fuel gas). In such a hydrogen engine (internal combustion engine 2), after performing work for maintenance or parts replacement, a trial run using city gas (first fuel gas) may be performed before operation using hydrogen gas (second fuel) as fuel. Hydrogen gas has a wider flammability range than city gas, and if hydrogen gas leaks from the fuel system or the fuel chamber 23, etc., the risk of fire is higher than if city gas leaks. For this reason, city gas may be used as fuel for the first trial run after work on the hydrogen engine (internal combustion engine 2). During the above trial run, it is necessary to switch the fuel gas supply system from the second fuel gas supply line 4 to the first fuel gas supply line 3. Being able to identify the type of gas supplied as fuel to the internal combustion engine 2 is desirable because it allows for an interlock to prevent the internal combustion engine 2 from starting, even if the fuel gas supply system is not switched during the above-mentioned trial run.

[0015] In the illustrated embodiment, the first fuel gas supply line 3 is connected on one end to the first fuel gas supply source 101 and on the other end to the internal combustion engine 2 (specifically, the combustion chambers 23 of each of the multiple cylinders 21) to which the first fuel gas is supplied. The first fuel gas supply source 101 is configured to store the first fuel gas. Examples of the first fuel gas supply source 101 include a storage tank for storing the first fuel gas and a pipeline (transport pipe) connected to the storage tank for transporting the first fuel gas.

[0016] The gaseous first fuel gas is guided from the first fuel gas supply source 101 to the first fuel gas supply line 3, flows through the first fuel gas supply line 3 from one side to the other, and is then guided to the internal combustion engine 2 (combustion chamber 23).

[0017] In the illustrated embodiment, one side of the second fuel gas supply line 4 is connected to the supply source 102 of the second fuel gas, and the other side is connected to the internal combustion engine 2 (specifically, the combustion chamber 23 of each of the plurality of cylinders 21) which is the destination of the second fuel gas supply. The supply source 102 of the second fuel gas is configured to store the second fuel gas. Examples of the supply source 102 of the second fuel gas include a storage tank for storing the second fuel gas and a pipeline (transport pipe) connected to the storage tank for transporting the second fuel gas.

[0018] The gaseous second fuel gas is guided from the supply source 102 of the second fuel gas to the second fuel gas supply line 4, flows through the second fuel gas supply line 4 from one side to the other side, and then is guided to the internal combustion engine 2 (combustion chamber 23).

[0019] (Shared line) As shown in FIGS. 1 to 3, the second fuel gas supply line 4 merges with the first fuel gas supply line 3 at the merging portion 11, and the downstream side (the side of the internal combustion engine 2) of the merging portion 11 of the first fuel gas supply line 3 and the second fuel gas supply line 4 becomes the shared line 5 with the first fuel gas supply line 3. The upstream side (the side of the supply source 101) in the flow direction of the first fuel gas with respect to the merging portion 11 of the first fuel gas supply line 3 is defined as the first fuel gas upstream line 3A, and the upstream side (the side of the supply source 102) in the flow direction of the second fuel gas with respect to the merging portion 11 of the second fuel gas supply line 4 is defined as the second fuel gas upstream line 4A.

[0020] Either the first fuel gas or the second fuel gas can be guided to the shared line 5. In the illustrated embodiment, the first fuel gas upstream line 3A includes a first manual on-off valve 12 provided in the first fuel gas upstream line

[0021] The internal combustion engine 2 has two operating modes: a first operating mode, which uses a first fuel gas as fuel, and a second operating mode, which uses a second fuel gas as fuel. Regardless of whether the internal combustion engine 2 is operating in the first or second operating mode, the third manual on / off valve 14 is in the open state.

[0022] When switching the operating mode of the internal combustion engine 2 from the second operating mode to the first operating mode, the operator operates the handle to close the second manual on-off valve 13 from the open state and open the first manual on-off valve 12 from the closed state. Similarly, when switching the operating mode of the internal combustion engine 2 from the first operating mode to the second operating mode, the operator operates the handle to close the first manual on-off valve 12 from the open state and open the second manual on-off valve 13 from the closed state.

[0023] If the second manual shut-off valve 13 is open in the first operating mode due to operator error with the handle, etc., there is a risk that the second fuel gas will flow into the internal combustion engine 2 (combustion chamber 23) through the shared line 5 in the first operating mode. Also, if the first manual shut-off valve 12 is open in the second operating mode due to operator error with the handle, etc., there is a risk that the first fuel gas will flow into the internal combustion engine 2 (combustion chamber 23) through the shared line 5 in the second operating mode.

[0024] (Supply gas pressure acquisition device) The supply gas pressure acquisition device 6 is configured to acquire the pressure (measured value) of the gas flowing through the shared line 5. In the illustrated embodiment, the supply gas pressure acquisition device 6 is a pressure sensor located downstream of the third manual on / off valve 14 of the shared line 5 (on the internal combustion engine 2 side). This pressure sensor is a device that senses the pressure (pressure signal) of the gas flowing through the shared line 5 and converts the sensed pressure (pressure signal) into an electrical signal for output.

[0025] Figure 4 is an explanatory diagram illustrating the pressure ranges of the gases (first fuel gas, second fuel gas) supplied to the internal combustion engine 2 in one embodiment of the present disclosure. In Figure 4, the first pressure range PR1 and the second pressure range PR2 are shown in a graph with pressure P on the vertical axis.

[0026] When the operating mode of the internal combustion engine 2 is the first operating mode, and the opening and closing states of the first manual on-off valve 12, the second manual on-off valve 13, and the third manual on-off valve 14 are normal, the first fuel gas (city gas in the illustrated example) flows through the shared line 5. The first fuel gas flowing through the shared line 5 is at a pressure that falls within a predetermined first pressure range PR1 (see Figure 4). The first pressure range PR1 has a first reference pressure UT1 as its upper limit and a second reference pressure LT1, which is lower than the first reference pressure UT1, as its lower limit. In other words, the first fuel gas flowing through the shared line 5 is at a pressure lower than the first reference pressure UT1 and at a pressure higher than the second reference pressure LT1.

[0027] When the operating mode of the internal combustion engine 2 is the second operating mode, and the open / closed states of the first manual on-off valve 12, the second manual on-off valve 13, and the third manual on-off valve 14 are normal, the second fuel gas (hydrogen gas in the illustrated example) flows through the shared line 5. The second fuel gas flowing through the shared line 5 is at a pressure belonging to a predetermined second pressure range PR2 (see Figure 4) that does not overlap with the first pressure range PR1. The second pressure range PR2 has the third reference pressure UT2 as its upper limit and the fourth reference pressure LT2, which is lower than the third reference pressure UT2, as its lower limit. In other words, the second fuel gas flowing through the shared line 5 is at a pressure lower than the third reference pressure UT2 and at a pressure higher than the fourth reference pressure LT2.

[0028] The lower limit pressure of the first pressure range PR1 (second reference pressure LT1) and the lower limit pressure of the second pressure range PR2 (fourth reference pressure LT2) are set to a pressure higher than atmospheric pressure. In the embodiment shown in Figure 4, the supply pressure of the first fuel gas (city gas in the illustrated example) is lower than the supply pressure of the second fuel gas (hydrogen gas in the illustrated example). Therefore, the first pressure range PR1 is lower than the second pressure range PR2, and the upper limit pressure of the first pressure range PR1 (first reference pressure UT1) is set to a lower pressure than the lower limit pressure of the second pressure range PR2 (fourth reference pressure LT2). Here, whether the first pressure range PR1 is higher or lower than the second pressure range PR2 is determined based on the type of first and second fuel gases, their supply pressure, etc. In other words, depending on the type of first and second fuel gas and the supply pressure, the first pressure range PR1 may be higher than the second pressure range PR2, and the lower limit pressure of the first pressure range PR1 (second reference pressure LT1) may be set higher than the upper limit pressure of the second pressure range PR2 (third reference pressure UT2).

[0029] (Control device) Figure 5 is a schematic diagram illustrating the configuration of a control device 7 in one embodiment of the present disclosure. The control device (controller) 7 is an electronic control unit for controlling the starting (driving) of the internal combustion engine 2. As shown in Figure 5, the control device 7 may be configured as a microcomputer including an input device 71 (input interface), an output device 72 (output interface), a storage device 73 (memory such as ROM or RAM, external storage device, etc.), and an arithmetic unit 74 (CPU). The control device 7 is configured such that, for example, the CPU operates (for example, performs calculations on data) according to instructions of a program loaded into the main memory of the above-mentioned memory, thereby realizing the starting control (driving control) of the internal combustion engine 2, which will be described later.

[0030] The control device 7 is capable of acquiring information regarding the operating mode of the internal combustion engine 2, specifically whether the internal combustion engine 2 is operating in the first operating mode or the second operating mode. For example, the information regarding the operating mode of the internal combustion engine 2 may be stored in the storage device 73, and the control device 7 may refer to the information regarding the operating mode of the internal combustion engine 2 stored in the storage device 73.

[0031] The control device 7 receives various signals from sensors installed in the starting control system 1 of the internal combustion engine 2, such as the supply gas pressure acquisition device 6, the first fuel gas pressure acquisition device 31, and the second fuel gas pressure acquisition device 41, via the input device 71 to the storage device 73 and the arithmetic unit 74. The storage device 73 stores various signals from sensors installed in the starting control system 1 of the internal combustion engine 2. The arithmetic unit 74 is configured to execute various controls according to the control program stored in the storage device 73.

[0032] In some embodiments of the startup control system 1, the control device 7 described above is configured not to start the internal combustion engine 2 in the first operating mode if the gas pressure (measured value) acquired by the supply gas pressure acquisition device 6 does not fall within the first pressure range PR1 (see Figure 4).

[0033] When the operating mode of the internal combustion engine 2 is the first operating mode using the first fuel gas, and the open / closed state of the manual on / off valves 12, 13, and 14 provided in the gaseous fuel supply system is normal, the pressure of the first fuel gas supplied to the internal combustion engine 2 through the shared line 5 falls within a predetermined first pressure range PR1. The start control system 1 of the internal combustion engine 2 can determine whether or not the gas flowing through the shared line 5 is the first fuel gas by monitoring the pressure of the gas flowing through the shared line 5 using the supply gas pressure acquisition device 6. In the operating mode using the first fuel gas, the control device 7 does not start the internal combustion engine 2 if the pressure of the gas flowing through the shared line 5 does not fall within the first pressure range PR1. The start control system 1 has a safety function that prevents the internal combustion engine 2 from being started by a gas other than the first fuel gas (for example, the second fuel gas, or a mixed gas of the first and second fuel gases) in the operating mode using the first fuel gas, thereby improving the safety of the internal combustion engine 2.

[0034] In some embodiments of the startup control system 1, the control device 7 described above is configured not to start the internal combustion engine 2 in the second operating mode if the gas pressure (measured value) acquired by the supply gas pressure acquisition device 6 does not fall within the second pressure range PR2 (see Figure 4).

[0035] When the operating mode of the internal combustion engine 2 is the second operating mode using the second fuel gas, and the open / closed state of the manual on / off valves 12, 13, and 14 provided in the gaseous fuel supply system is normal, the pressure of the second fuel gas supplied to the internal combustion engine 2 through the shared line 5 falls within a predetermined second pressure range PR2. The start control system 1 of the internal combustion engine 2 can determine whether or not the gas flowing through the shared line 5 is the second fuel gas by monitoring the pressure of the gas flowing through the shared line 5 using the supply gas pressure acquisition device 6. In the operating mode using the second fuel gas, the control device 7 does not start the internal combustion engine 2 if the pressure of the gas flowing through the shared line 5 does not fall within the second pressure range PR2. The start control system 1 has a safety function that prevents the internal combustion engine 2 from being started by a gas other than the second fuel gas (for example, the first fuel gas, or a mixed gas of the first and second fuel gases) in the operating mode using the second fuel gas, thereby improving the safety of the internal combustion engine 2.

[0036] (First fuel gas pressure acquisition device) In some embodiments of the startup control system 1, as shown in Figures 1 and 2, a first fuel gas pressure acquisition device 31 is provided, which is configured to acquire the pressure of the first fuel gas flowing upstream of the confluence 11 of the first fuel gas supply line 3. The first pressure range PR1 described above is a pressure range set based on the pressure (measured value) of the first fuel gas acquired by the first fuel gas pressure acquisition device 31.

[0037] The first fuel gas pressure acquisition device 31 is configured to acquire the pressure (measured value) of the gas flowing upstream of the first manual on-off valve 12 (on the supply source 101 side) of the first fuel gas upstream line 3A. In the illustrated embodiment, the first fuel gas pressure acquisition device 31 is a pressure sensor provided upstream of the first manual on-off valve 12 of the first fuel gas upstream line 3A. The pressure sensor is a device that senses the pressure (pressure signal) of the gas flowing in the first fuel gas upstream line 3A and converts the sensed pressure (pressure signal) into an electrical signal for output.

[0038] The control device 7 is configured to set the first pressure range PR1 based on the pressure (measured value) of the first fuel gas acquired by the first fuel gas pressure acquisition device 31. In one embodiment, the control device 7 stores time-series data of the pressure (measured value) of the first fuel gas acquired by the first fuel gas pressure acquisition device 31 in the storage device 73 and extracts measured values ​​for a predetermined period from the time-series data. The control device 7 then calculates the average value of the extracted measured values ​​for the predetermined period and sets the calculated average value as the reference value of the first pressure range PR1 (for example, the median value which is the average of the upper and lower pressure limits of the first pressure range PR1). The upper pressure limit of the first pressure range PR1 is obtained by adding a predetermined margin to the reference value so that it is higher, and the lower pressure limit of the first pressure range PR1 is obtained by subtracting a predetermined margin so that it is lower than the reference value. The first pressure range PR1 includes the pressure (pressure amplitude) of the first fuel gas acquired by the first fuel gas pressure acquisition device 31 during the predetermined period.

[0039] Depending on the supply method of the first fuel gas, the pressure of the first fuel gas introduced into the first fuel gas supply line 3 may fluctuate relatively significantly. By setting the first pressure range PR1 so as not to overlap with the second pressure range PR2, based on the pressure of the first fuel gas acquired by the first fuel gas pressure acquisition device 31, the startup control system 1 can determine whether the gas flowing through the shared line 5 is the first fuel gas, even when the pressure of the first fuel gas introduced into the first fuel gas supply line 3 fluctuates relatively significantly.

[0040] In some embodiments of the internal combustion engine 2, the startup control system 1 includes a first pressure regulating valve 32 located upstream (on the supply source 101 side) of the first fuel gas pressure acquisition device 31 in the first fuel gas supply line 3, as shown in Figure 2. The first pressure regulating valve 32 is configured to adjust the pressure so that the pressure of the first fuel gas acquired by the first fuel gas pressure acquisition device 31 falls within a first target pressure range TPR1 (see Figure 4). The first target pressure range TPR1 has a first target pressure TUT1 as its upper limit and a second target pressure TLT1, which is lower than the first target pressure TUT1, as its lower limit.

[0041] The first pressure regulating valve 32 has a pressure reducing mechanism that reduces the pressure of the first fuel gas to below the upper limit pressure (first target pressure TUT1) when a high-pressure first fuel gas exceeding the upper limit pressure (first target pressure TUT1) is introduced into the first pressure regulating valve 32. The first pressure regulating valve 32 may also be configured to close when a low-pressure first fuel gas below the lower limit pressure (second target pressure TLT1) is introduced into the first pressure regulating valve 32, or it may have a pressure increasing mechanism that increases the pressure of the first fuel gas to above the lower limit pressure.

[0042] In the embodiment shown in Figure 4, the first target pressure range TPR1 is included within the range of the first pressure range PR1. That is, the upper limit of the first target pressure range TPR1 is lower than the upper limit of the first pressure range PR1, and the lower limit of the first target pressure range TPR1 is higher than the lower limit of the first pressure range PR1. In some other embodiments, the upper limit of the first target pressure range TPR1 may be set to the same pressure as the upper limit of the first pressure range PR1. Also, the lower limit of the first target pressure range TPR1 may be set to the same pressure as the lower limit of the first pressure range PR1.

[0043] By adjusting the pressure using the first pressure regulating valve 32, pressure fluctuations of the first fuel gas flowing through the shared line 5 located downstream of the first pressure regulating valve 32 can be suppressed. The startup control system 1 can accurately determine whether the gas flowing through the shared line 5 is the first fuel gas or the second fuel gas by adjusting the pressure of the first fuel gas flowing through the shared line 5 to a pressure that falls within the first target pressure range TPR1.

[0044] (Second fuel gas pressure acquisition device) In some embodiments of the startup control system 1, as shown in Figures 1 and 2, a second fuel gas pressure acquisition device 41 is provided, which is configured to acquire the pressure of the second fuel gas flowing upstream of the confluence 11 of the second fuel gas supply line 4. The second pressure range PR2 described above is a pressure range set based on the pressure (measured value) of the second fuel gas acquired by the second fuel gas pressure acquisition device 41.

[0045] The second fuel gas pressure acquisition device 41 is configured to acquire the pressure (measured value) of the gas flowing upstream of the second manual on-off valve 13 (on the supply source 102 side) of the second fuel gas upstream line 4A. In the illustrated embodiment, the second fuel gas pressure acquisition device 41 is a pressure sensor provided upstream of the second manual on-off valve 13 of the second fuel gas upstream line 4A. The pressure sensor is a device that senses the pressure (pressure signal) of the gas flowing in the second fuel gas upstream line 4A and converts the sensed pressure (pressure signal) into an electrical signal for output.

[0046] The control device 7 is configured to set the second pressure range PR2 based on the pressure (measured value) of the second fuel gas acquired by the second fuel gas pressure acquisition device 41. In one embodiment, the control device 7 stores time-series data of the pressure (measured value) of the second fuel gas acquired by the second fuel gas pressure acquisition device 41 in the storage device 73 and extracts measured values ​​for a predetermined period from the time-series data. The control device 7 then calculates the average value of the extracted measured values ​​for the predetermined period and uses the calculated average value as the reference value for the second pressure range PR2 (for example, the median value which is the average of the upper and lower pressure limits of the second pressure range PR2). The upper pressure limit of the second pressure range PR2 is obtained by adding a predetermined margin to the reference value so that it is higher, and the lower pressure limit of the second pressure range PR2 is obtained by subtracting a predetermined margin so that it is lower than the reference value. The second pressure range PR2 includes the pressure (pressure amplitude) of the second fuel gas acquired by the second fuel gas pressure acquisition device 41 during the predetermined period.

[0047] Depending on the supply method of the second fuel gas, the pressure of the second fuel gas introduced into the second fuel gas supply line 4 may fluctuate relatively significantly. By setting the second pressure range PR2 so as not to overlap with the first pressure range PR1, based on the pressure of the second fuel gas acquired by the second fuel gas pressure acquisition device 41, the startup control system 1 can determine whether the gas flowing through the shared line 5 is the first fuel gas, even when the pressure of the second fuel gas introduced into the second fuel gas supply line 4 fluctuates relatively significantly.

[0048] In some embodiments of the internal combustion engine 2, the startup control system 1 includes a second pressure regulating valve 42 located upstream (on the supply source 102 side) of the second fuel gas pressure acquisition device 41 in the second fuel gas supply line 4, as shown in Figure 2. The second pressure regulating valve 42 is configured to adjust the pressure so that the pressure of the second fuel gas acquired by the second fuel gas pressure acquisition device 41 falls within the second target pressure range TPR2 (see Figure 4). The second target pressure range TPR2 has a third target pressure TUT2 as its upper limit and a fourth target pressure TLT2, which is lower than the third target pressure TUT2, as its lower limit.

[0049] The second pressure regulating valve 42 has a pressure reducing mechanism that reduces the pressure of the second fuel gas to below the upper limit pressure (third target pressure TUT2) when a high-pressure second fuel gas exceeding the upper limit pressure (third target pressure TUT2) is introduced into the second pressure regulating valve 42. The second pressure regulating valve 42 may also be configured to close when a low-pressure second fuel gas below the lower limit pressure (fourth target pressure TLT2) is introduced into the second pressure regulating valve 42, or it may have a pressure increasing mechanism that increases the pressure of the second fuel gas to above the lower limit pressure.

[0050] In the embodiment shown in Figure 4, the second target pressure range TPR2 is included within the range of the second pressure range PR2. That is, the upper limit of the second target pressure range TPR2 is lower than the upper limit of the second pressure range PR2, and the lower limit of the second target pressure range TPR2 is higher than the lower limit of the second pressure range PR2. In some other embodiments, the upper limit of the second target pressure range TPR2 may be set to the same pressure as the upper limit of the second pressure range PR2. Also, the lower limit of the second target pressure range TPR2 may be set to the same pressure as the lower limit of the second pressure range PR2.

[0051] By adjusting the pressure using the second pressure regulating valve 42, pressure fluctuations of the second fuel gas flowing through the shared line 5 located downstream of the second pressure regulating valve 42 can be suppressed. The startup control system 1 can accurately determine whether the gas flowing through the shared line 5 is the first fuel gas or the second fuel gas by adjusting the pressure of the second fuel gas flowing through the shared line 5 to a pressure that falls within the second target pressure range TPR2.

[0052] In some embodiments of the internal combustion engine 2, as shown in Figure 3, the startup control system 1 does not need to include a first fuel gas pressure acquisition device 31 and a first pressure regulating valve 32 if the pressure of the first fuel gas supplied from the first fuel gas supply source 101 and led to the shared line 5 stably falls within the first pressure range PR1. This startup control system 1 can be implemented at a lower cost compared to the case in which the first fuel gas pressure acquisition device 31 and the first pressure regulating valve 32 are included.

[0053] In some embodiments of the internal combustion engine 2, as shown in Figure 3, the startup control system 1 does not need to include a second fuel gas pressure acquisition device 41 and a second pressure regulating valve 42 if the pressure of the second fuel gas supplied from the second fuel gas supply source 102 and led to the shared line 5 is stably within the second pressure range PR2. This startup control system 1 can be implemented at a lower cost compared to the case in which the second fuel gas pressure acquisition device 41 and the second pressure regulating valve 42 are included.

[0054] In some embodiments, the start control system 1 for an internal combustion engine 2, as shown in Figures 1 to 3, is provided on the side of the internal combustion engine 2 that is closer to the supply gas pressure acquisition device 6 for the shared line 5, and includes at least one on-off valve 8 for opening and closing the shared line 5. The on-off valve 8 has a valve body that opens and closes the line to which the on-off valve 8 is provided, and the valve body is configured to open and close in response to an on-off instruction from a control device 7. The control device 7 is electrically connected to the on-off valve 8 via wired or wireless communication and is configured to give an on-off instruction to the on-off valve 8 (transmit an on-off instruction signal).

[0055] In some embodiments, the control device 7 is configured such that, in an operating mode using a first fuel gas, if the gas pressure (measured value) acquired by the supply gas pressure acquisition device 6 does not fall within the first pressure range PR1, at least one on-off valve 8 is closed. Here, "on-off valve 8 is closed" means that if the on-off valve 8 is in a closed state, the control device 7 does not issue an open command to the on-off valve 8 and maintains the closed state of the on-off valve 8; and if the on-off valve 8 is in an open state, the control device 7 issues a close command to the on-off valve 8, and the on-off valve 8 transitions to a closed state in response to the close command. Before starting operation of the internal combustion engine 2 in the first or second operating mode, the on-off valve 8 is in a closed state.

[0056] In the operating mode using the first fuel gas, the control device 7 closes the on-off valve 8 if the pressure of the gas flowing through the shared line 5 does not fall within the first pressure range PR1, thereby suppressing the flow of gas through the shared line 5 to the internal combustion engine 2. By suppressing the supply of gas to the internal combustion engine 2 through the shared line 5, the control device 7 prevents the internal combustion engine 2 from starting.

[0057] In some embodiments, the control device 7 is configured such that, in an operating mode using a second fuel gas, at least one on-off valve 8 is closed if the gas pressure (measured value) acquired by the supply gas pressure acquisition device 6 does not fall within the second pressure range PR2.

[0058] In the operating mode using the second fuel gas, the control device 7 closes the on-off valve 8 if the pressure of the gas flowing through the shared line 5 does not fall within the second pressure range PR2, thereby suppressing the flow of gas through the shared line 5 to the internal combustion engine 2. By suppressing the supply of gas to the internal combustion engine 2 through the shared line 5, the control device 7 prevents the internal combustion engine 2 from starting.

[0059] In some embodiments of the starting control system 1 for an internal combustion engine 2, as shown in Figures 1 to 3, the shared line 5 described above includes a plurality of branch pipes 52 corresponding to each of a plurality of cylinders 21, and a common main pipe 51 to which the plurality of branch pipes 52 are connected. Each of the plurality of branch pipes 52 has one end connected to the cylinder 21 to which the branch pipe 52 corresponds, and the other end connected to the main pipe 51. Gaseous fuel (first fuel gas, second fuel gas) is guided from the branch pipes 52 to the combustion chambers 23 of the cylinders 21 corresponding to the branch pipes 52 via the main pipe 51.

[0060] In some embodiments, the above-described at least one on-off valve 8 includes a main pipe-side on-off valve 81 for opening and closing the supply gas pressure acquisition device 6 on the internal combustion engine 2 side of the main pipe 51. The control device 7 prevents the internal combustion engine 2 from starting by closing the main pipe-side on-off valve 81 provided on the main pipe 51.

[0061] In some embodiments, the at least one on-off valve 8 described above includes a plurality of branch pipe on-off valves 82 for opening and closing each of the plurality of branch pipes 52. The branch pipe on-off valves 82 may also be fuel injectors for injecting gaseous fuel into the combustion chamber 23. The control device 7 prevents the internal combustion engine 2 from starting by closing the branch pipe on-off valves 82 provided in each of the plurality of branch pipes 52, thereby suppressing the supply of gas to the internal combustion engine 2 through the shared line 5.

[0062] In some embodiments of the starting control system 1 for the internal combustion engine 2, the second fuel gas described above is hydrogen gas or ammonia gas. In this case, the second fuel gas (hydrogen gas or ammonia gas) is a gas with a relatively high risk of leakage. The starting control system 1 has a safety function that prevents the starting of the internal combustion engine 2 in the operating mode using the first fuel gas, by using gases other than the first fuel gas, specifically gases including the second fuel gas, thereby suppressing abnormal combustion in the combustion chamber 23 of the internal combustion engine 2, the generation of unburned second fuel gas, leakage, etc.

[0063] In the starting control system 1 for the internal combustion engine 2 according to several embodiments, the first fuel gas described above is city gas mainly composed of natural gas. In this case, the first fuel gas (city gas) is a gas with a relatively low risk of leakage compared to the second fuel gas (hydrogen gas or ammonia gas). The operating mode using the first fuel gas has different combustion control parameters for controlling combustion in the combustion chamber 23 of the internal combustion engine 2, such as ignition timing and intake pressure, compared to the operating mode using the second fuel gas. The starting control system 1 has a safety function that prevents the starting of the internal combustion engine 2 depending on the gas other than the first fuel gas, specifically gas including the second fuel gas, in the operating mode using the first fuel gas. This suppresses abnormal combustion, generation of unburned second fuel gas, leakage, etc., in the combustion chamber 23 of the internal combustion engine 2 due to combustion based on inappropriate combustion control parameters.

[0064] In this specification, expressions describing relative or absolute arrangements such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" shall not only describe such arrangements strictly, but also describe states of relative displacement with tolerances or angles or distances that allow for the same function to be achieved. For example, expressions such as "identical," "equal," and "homogeneous" that describe things being in an equal state not only describe a state of being strictly equal, but also describe a state in which there is a tolerance or a difference that is sufficient to achieve the same function. Furthermore, in this specification, expressions describing shapes such as quadrilaterals and cylindrical shapes shall not only represent geometrically precise quadrilaterals and cylindrical shapes, but also shapes that include uneven surfaces, chamfered surfaces, etc., to the extent that the same effect can be achieved. Furthermore, in this specification, the expressions “equipment,” “includes,” or “possess” of a component are not exclusive expressions that exclude the existence of other components.

[0065] This disclosure is not limited to the embodiments described above, but also includes modified forms of the embodiments described above, as well as forms that combine these forms as appropriate.

[0066] The contents described in some of the embodiments above can be understood, for example, as follows:

[0067] 1) A start control system (1) for an internal combustion engine (2) according to at least one embodiment of the present disclosure, A first fuel gas supply line (3) for guiding a first fuel gas belonging to a predetermined first pressure range to an internal combustion engine (2), A second fuel gas supply line (4) for supplying a second fuel gas belonging to a predetermined second pressure range that does not overlap with the first pressure range to the internal combustion engine (2), wherein the second fuel gas supply line (4) is a shared line (5) with the first fuel gas supply line (3) on the side of the internal combustion engine (2) that is closer to the confluence (11) of the first fuel gas supply line (3) and the second fuel gas supply line (4), A supply gas pressure acquisition device (6) configured to acquire the pressure of the gas flowing through the shared line (5), The device (7) for controlling the starting of the internal combustion engine (2) is configured to prevent the starting of the internal combustion engine (2) if, in an operating mode using the first fuel gas, the pressure of the gas acquired by the supply gas pressure acquisition device (6) does not fall within the first pressure range.

[0068] According to the configuration described in 1) above, the first fuel gas supplied to the internal combustion engine (2) through the shared line (5) is within a predetermined first pressure range. The starting control system (1) of the internal combustion engine (2) can determine whether the gas flowing through the shared line (5) is the first fuel gas by monitoring the pressure of the gas flowing through the shared line (5) using the supply gas pressure acquisition device (6). In the operating mode using the first fuel gas as fuel, the control device (7) will not start the internal combustion engine (2) if the pressure of the gas flowing through the shared line (5) does not fall within the first pressure range. The starting control system (1) can improve the safety of the internal combustion engine (2) by having a safety function that prevents the internal combustion engine (2) from being started by gases other than the first fuel gas in the operating mode using the first fuel gas as fuel.

[0069] 2) In some embodiments, the starting control system (1) for the internal combustion engine (2) described in 1) above, The system further includes a first fuel gas pressure acquisition device (31) configured to acquire the pressure of the first fuel gas flowing upstream of the confluence (11) of the first fuel gas supply line (3), The first pressure range is a pressure range set based on the pressure of the first fuel gas acquired by the first fuel gas pressure acquisition device (31).

[0070] According to the configuration described in 2) above, depending on the supply method of the first fuel gas, the pressure of the first fuel gas introduced into the first fuel gas supply line (3) may fluctuate relatively significantly. By setting the first pressure range so as not to overlap with the second pressure range, based on the pressure of the first fuel gas acquired by the first fuel gas pressure acquisition device (31), the startup control system (1) can determine whether or not the gas flowing through the shared line (5) is the first fuel gas, even when the pressure of the first fuel gas introduced into the first fuel gas supply line (3) fluctuates relatively significantly.

[0071] 3) In some embodiments, the starting control system (1) for the internal combustion engine (2) described in 2) above, The system further includes a first pressure regulating valve (32) located upstream of the first fuel gas pressure acquisition device (31) in the first fuel gas supply line (3), the first pressure regulating valve (32) being configured to adjust the pressure so that the pressure of the first fuel gas acquired by the first fuel gas pressure acquisition device (31) falls within a first target pressure range.

[0072] According to the configuration described in 3) above, pressure fluctuations in the first fuel gas flowing through the shared line (5) located downstream of the first pressure regulating valve (32) can be suppressed by regulating the pressure with the first pressure regulating valve (32). The startup control system (1) can accurately determine whether the gas flowing through the shared line (5) is the first fuel gas or the second fuel gas by regulating the pressure of the first fuel gas flowing through the shared line (5) to a pressure that falls within the first target pressure range.

[0073] 4) In some embodiments, the starting control system (1) for the internal combustion engine (2) described in 2) or 3) above, The system further includes a second fuel gas pressure acquisition device (41) configured to acquire the pressure of the second fuel gas flowing upstream of the confluence (11) of the second fuel gas supply line (4), The second pressure range is a pressure range set based on the pressure of the second fuel gas acquired by the second fuel gas pressure acquisition device (41).

[0074] According to the configuration described in 4) above, depending on the supply method of the second fuel gas, the pressure of the second fuel gas introduced into the second fuel gas supply line (4) may fluctuate relatively significantly. By setting the second pressure range so as not to overlap with the first pressure range, based on the pressure of the second fuel gas acquired by the second fuel gas pressure acquisition device (41), the startup control system (1) can determine whether the gas flowing through the shared line (5) is the first fuel gas, even when the pressure of the second fuel gas introduced into the second fuel gas supply line (4) fluctuates relatively significantly.

[0075] 5) In some embodiments, the starting control system (1) for the internal combustion engine (2) described in 4) above, The system further includes a second pressure regulating valve (42) located upstream of the second fuel gas pressure acquisition device (41) in the second fuel gas supply line (4), the second pressure regulating valve (42) being configured to adjust the pressure so that the pressure of the second fuel gas acquired by the second fuel gas pressure acquisition device (41) falls within a second target pressure range.

[0076] According to the configuration described in 5) above, pressure fluctuations in the second fuel gas flowing through the shared line (5) located downstream of the second pressure regulating valve (42) can be suppressed by regulating the pressure with the second pressure regulating valve (42). The startup control system (1) can accurately determine whether the gas flowing through the shared line (5) is the first fuel gas or the second fuel gas by regulating the pressure of the second fuel gas flowing through the shared line (5) to a pressure that falls within the second target pressure range.

[0077] 6) In some embodiments, the starting control system (1) for an internal combustion engine (2) as described in any of 1) to 5) above, The control device (7) is configured to not start the internal combustion engine (2) in the operating mode using the second fuel gas if the pressure of the gas acquired by the supply gas pressure acquisition device (6) does not fall within the second pressure range.

[0078] According to the configuration in 6) above, the second fuel gas supplied to the internal combustion engine (2) through the shared line (5) is within a predetermined second pressure range. The start control system (1) of the internal combustion engine (2) can determine whether the gas flowing through the shared line (5) is the second fuel gas by monitoring the pressure of the gas flowing through the shared line (5) using the supply gas pressure acquisition device (6). In the operating mode using the second fuel gas as fuel, the control device (7) will not start the internal combustion engine (2) if the pressure of the gas flowing through the shared line (5) does not fall within the second pressure range. The start control system (1) can improve the safety of the internal combustion engine (2) by having a safety function that prevents the internal combustion engine (2) from being started by gases other than the second fuel gas in the operating mode using the second fuel gas as fuel.

[0079] 7) In some embodiments, a starting control system (1) for an internal combustion engine (2) as described in any of 1) to 6) above, The shared line (5) is provided on the internal combustion engine (2) side of the supply gas pressure acquisition device (6), and further comprises at least one on-off valve (8) for opening and closing the shared line (5), The control device (7) is configured such that, in an operating mode using the first fuel gas, at least one on-off valve (8) is closed if the gas pressure acquired by the supply gas pressure acquisition device (6) does not fall within the first pressure range.

[0080] According to the configuration described in 7) above, in the operating mode using the first fuel gas, the control device (7) closes the on-off valve (8) when the pressure of the gas flowing through the shared line (5) does not fall within the first pressure range, thereby suppressing the flow of the gas through the shared line (5) to the internal combustion engine (2). This control device (7) prevents the internal combustion engine (2) from starting by suppressing the supply of gas to the internal combustion engine (2) through the shared line (5).

[0081] 8) In some embodiments, the starting control system (1) for the internal combustion engine (2) described in 7) above, The internal combustion engine (2) has a plurality of cylinders (21), The shared line (5) includes a plurality of branch pipes (52) corresponding to each of the plurality of cylinders (21), and a common main pipe (51) to which the plurality of branch pipes (52) are connected. The at least one on-off valve (8) includes a main pipe on-off valve (81) for opening and closing the main pipe (51) on the side of the supply gas pressure acquisition device (6) that is connected to the internal combustion engine (2).

[0082] According to the configuration described in 8) above, the control device (7) prevents the internal combustion engine (2) from starting by closing the main pipe-side shut-off valve (81) provided on the main pipe (51).

[0083] 9) In some embodiments, the starting control system (1) for the internal combustion engine (2) described in 7) or 8) above, The internal combustion engine (2) has a plurality of cylinders (21), The shared line (5) includes a plurality of branch pipes (52) corresponding to each of the plurality of cylinders (21), and a common main pipe (51) to which the plurality of branch pipes (52) are connected. The at least one on-off valve (8) includes a plurality of branch pipe on-off valves (82) for opening and closing each of the plurality of branch pipes (52).

[0084] According to the configuration in 9) above, the control device (7) prevents the internal combustion engine (2) from starting by closing the branch pipe-side on-off valves (82) provided on each of the branch pipes (52).

[0085] 10) In some embodiments, a starting control system (1) for an internal combustion engine (2) as described in any of 1) to 9) above, The second fuel gas is hydrogen gas or ammonia gas.

[0086] According to the configuration described in 10) above, the second fuel gas is hydrogen gas or ammonia gas, which is a gas with a relatively high risk of leakage. The startup control system (1) has a safety function that prevents the internal combustion engine (2) from starting if the gas other than the first fuel gas, specifically gas including the second fuel gas, is used in the operating mode using the first fuel gas, thereby suppressing abnormal combustion in the combustion chamber (23) of the internal combustion engine (2), the generation of unburned second fuel gas, leakage, etc.

[0087] 11) In some embodiments, the starting control system (1) for the internal combustion engine (2) described in 10) above, The first fuel gas is city gas, which mainly consists of natural gas.

[0088] According to the configuration described in 11) above, the first fuel gas is city gas, which has a relatively low risk of leakage compared to the second fuel gas (hydrogen gas or ammonia gas). The operating mode using the first fuel gas has different combustion control parameters for controlling combustion in the combustion chamber (23) of the internal combustion engine (2), such as ignition timing and intake pressure, compared to the operating mode using the second fuel gas. The starting control system (1) has a safety function that prevents the internal combustion engine (2) from starting depending on the gas other than the first fuel gas, specifically gases including the second fuel gas, in the operating mode using the first fuel gas. This prevents abnormal combustion, generation of unburned second fuel gas, leakage, etc., in the combustion chamber (23) of the internal combustion engine (2) due to combustion based on inappropriate combustion control parameters. [Explanation of Symbols]

[0089] 1. Startup control system 11. Confluence 12, 13, 14 Manually operated valves 2 Internal Combustion Engine 21 cylinders 22 pistons 23 Combustion chamber 3. First fuel gas supply line 31. First Fuel Gas Pressure Acquisition Device 32. First pressure regulating valve 4. Second fuel gas supply line 41. Second Fuel Gas Pressure Acquisition Device 42. Second pressure regulating valve 5 Shared Line 51 Main pipe 52 Branch pipe 6. Supply gas pressure acquisition device 7 Control device 71 Input device 72 Output device 73 Storage device 74 Arithmetic unit 8. Shut-off valves 81 Main pipe side shut-off valve 82 Branch pipe side on / off valve

Claims

1. A first fuel gas supply line for supplying a first fuel gas belonging to a predetermined first pressure range to an internal combustion engine, A second fuel gas supply line for supplying a second fuel gas belonging to a predetermined second pressure range that does not overlap with the first pressure range to the internal combustion engine, wherein the second fuel gas supply line is a shared line with the first fuel gas supply line on the side of the internal combustion engine that is closer to the confluence of the first fuel gas supply line and the second fuel gas supply line, A supply gas pressure acquisition device configured to acquire the pressure of the gas flowing through the aforementioned shared line, A control device for controlling the starting of the internal combustion engine, comprising: a control device configured to prevent the starting of the internal combustion engine in an operating mode using the first fuel gas if the pressure of the gas acquired by the supply gas pressure acquisition device does not fall within the first pressure range; An internal combustion engine start-up control system.

2. The system further comprises a first fuel gas pressure acquisition device configured to acquire the pressure of the first fuel gas flowing upstream of the confluence of the first fuel gas supply line, The first pressure range is a pressure range set based on the pressure of the first fuel gas acquired by the first fuel gas pressure acquisition device. The starting control system for an internal combustion engine according to claim 1.

3. A first pressure regulating valve is provided upstream of the first fuel gas pressure acquisition device in the first fuel gas supply line, and further comprises a first pressure regulating valve configured to adjust the pressure so that the pressure of the first fuel gas acquired by the first fuel gas pressure acquisition device falls within a first target pressure range. The starting control system for an internal combustion engine according to claim 2.

4. The system further comprises a second fuel gas pressure acquisition device configured to acquire the pressure of the second fuel gas flowing upstream of the confluence of the second fuel gas supply line, The second pressure range is a pressure range set based on the pressure of the second fuel gas acquired by the second fuel gas pressure acquisition device. The starting control system for an internal combustion engine according to claim 2 or 3.

5. A second pressure regulating valve is provided upstream of the second fuel gas pressure acquisition device in the second fuel gas supply line, and further comprises a second pressure regulating valve configured to adjust the pressure so that the pressure of the second fuel gas acquired by the second fuel gas pressure acquisition device falls within a second target pressure range. The starting control system for an internal combustion engine according to claim 4.

6. The control device is configured to prevent the internal combustion engine from starting if, in an operating mode using the second fuel gas, the pressure of the gas acquired by the supply gas pressure acquisition device does not fall within the second pressure range. A starting control system for an internal combustion engine according to any one of claims 1 to 3.

7. The shared line is provided on the internal combustion engine side of the supply gas pressure acquisition device, and further comprises at least one on-off valve for opening and closing the shared line, The control device is configured such that, in an operating mode using the first fuel gas, at least one on-off valve is closed if the gas pressure acquired by the supply gas pressure acquisition device does not fall within the first pressure range. A starting control system for an internal combustion engine according to any one of claims 1 to 3.

8. The aforementioned internal combustion engine has multiple cylinders, The shared line includes a plurality of branch pipes corresponding to each of the plurality of cylinders, and a common main pipe to which the plurality of branch pipes are connected. The at least one on-off valve includes a main pipe on-off valve for opening and closing the main pipe on the internal combustion engine side of the supply gas pressure acquisition device, The starting control system for an internal combustion engine according to claim 7.

9. The aforementioned internal combustion engine has multiple cylinders, The shared line includes a plurality of branch pipes corresponding to each of the plurality of cylinders, and a common main pipe to which the plurality of branch pipes are connected. The at least one on-off valve includes a plurality of branch pipe on-off valves for opening and closing each of the plurality of branch pipes, The starting control system for an internal combustion engine according to claim 7.

10. The second fuel gas is hydrogen gas or ammonia gas. A starting control system for an internal combustion engine according to any one of claims 1 to 3.

11. The first fuel gas is city gas, which mainly consists of natural gas. The starting control system for an internal combustion engine according to claim 10.

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