Control device, gas engine, control method, and program

Abstract

Provided is a control device making it possible to suppress an increase in pressure downstream of an electronic valve when a vent valve opened during load rejection is closed. An engine comprises: a fuel supply system for supplying fuel to the engine; a valve provided to the fuel supply system; a fuel injection device for adjusting the flow rate of the fuel on the downstream side of the valve; a vent line having one end connected between the fuel injection device and the valve in the fuel supply system and another end open to the atmosphere; and a vent valve provided to the vent line. With respect to the engine, the control device is provided with: a means for opening the vent valve when load rejection occurs; and a means for closing the vent valve after the vent valve has been opened and also controlling the opening degree of the valve to a post-load-rejection opening degree, which is an opening degree corresponding to the output of the engine after the load rejection.

Description

Control Device, Gas Engine, Control Method, and Program

[0001] The present disclosure relates to a control device, a gas engine, a control method, and a program. The present disclosure claims priority based on Japanese Patent Application No. 2025-018234 filed in Japan on February 6, 2025, and incorporates the content herein by reference.

[0002] An electronic valve for fuel pressure adjustment used in the fuel pipe of a gas engine controls the fuel pressure by electronic control. In a gas engine having a vent valve in the fuel pipe, the vent valve may be opened to appropriately maintain the fuel pressure during load interruption. When the responsiveness of the electronic valve is poor, when closing the vent valve that has once opened during load interruption, the operation of reducing the opening degree of the electronic valve is not in time, and the pressure tends to rise downstream of the electronic valve by the amount of fuel that has been discharged to the outside of the system by the opening of the vent valve. Depending on the degree of pressure increase, an overshoot of the fuel pressure may occur, which may adversely affect fuel injection.

[0003] Patent Document 1 describes discharging fuel from a fuel gas discharge pipe provided with an on-off valve (vent valve) during load interruption and increasing the gain of a pressure regulating valve (electronic valve) during load interruption. Patent Document 1 does not disclose a technique for dealing with the pressure increase downstream of the pressure regulating valve due to the response delay of the pressure regulating valve.

[0004] Japanese Unexamined Patent Application Publication No. 2008-115737

[0005] Control for suppressing the pressure increase downstream of the electronic valve when closing the vent valve that has opened during load interruption is required.

[0006] The present disclosure provides a control device, a gas engine, a control method, and a program capable of solving the above problems.

[0007] According to one aspect of the present disclosure, a control device is provided for an engine that includes a fuel supply system for supplying fuel to an engine, a valve provided in the fuel supply system, a fuel injection device for adjusting the flow rate of the fuel downstream of the valve, a vent line having one end connected between the valve and the fuel injection device in the fuel supply system and the other end open to the atmosphere, and a vent valve provided in the vent line, wherein the control device includes means for opening the vent valve when a load cutoff occurs, and means for closing the vent valve after it has been opened and controlling the opening degree of the valve to a post-load cutoff opening degree that indicates an opening degree corresponding to the output of the engine after the load cutoff.

[0008] According to one aspect of the present disclosure, a gas engine includes a fuel supply system for supplying gaseous fuel to the engine, a valve provided in the fuel supply system, a fuel injection device downstream of the valve that adjusts the flow rate of the gaseous fuel, a vent line having one end connected between the valve and the fuel injection device in the fuel supply system and the other end open to the atmosphere, a vent valve provided in the vent line, and the control device described above.

[0009] According to one aspect of the present disclosure, a control method provides an engine comprising: a fuel supply system for supplying fuel to the engine; a valve provided in the fuel supply system; a fuel injection device for adjusting the flow rate of the fuel downstream of the valve; a vent line having one end connected between the valve and the fuel injection device in the fuel supply system and the other end open to the atmosphere; and a vent valve provided in the vent line, wherein when a load cutoff occurs, the vent valve is opened, the vent valve is closed after it has been opened, and the opening degree of the valve is controlled to a post-load cutoff opening degree that indicates an opening degree corresponding to the output of the engine after the load cutoff.

[0010] According to one aspect of the present disclosure, a program causes a computer to perform a process in an engine including a fuel supply system for supplying fuel to an engine, a valve provided in the fuel supply system, a fuel injection device for adjusting the flow rate of the fuel downstream of the valve, a vent line having one end connected between the valve and the fuel injection device in the fuel supply system and the other end open to the atmosphere, and a vent valve provided in the vent line, wherein when a load cutoff occurs, the program opens the vent valve, closes the vent valve after opening it, and controls the opening degree of the valve to a post-load cutoff opening degree that indicates an opening degree corresponding to the output of the engine after the load cutoff.

[0011] According to the control device, gas engine, control method, and program described above, it is possible to suppress the pressure rise downstream of the electronic valve when the vent valve, which was opened when the load was cut off, is closed.

[0012] These are schematic diagrams of the gas engine according to each embodiment. Figure 1 illustrates the control during load shedding according to the first embodiment. Figure 2 illustrates the control during load shedding according to the first embodiment. This is a flowchart showing an example of the control during load shedding according to the first embodiment. Figure 1 illustrates the control during load shedding according to the second embodiment. Figure 2 illustrates the control during load shedding according to the second embodiment. This is a flowchart showing an example of the control during load shedding according to the second embodiment. This figure illustrates the control during load shedding according to the third embodiment. This is a flowchart showing an example of the control during load shedding according to the third embodiment. These are schematic diagrams showing an example of the hardware configuration of the control device according to each embodiment.

[0013] <First Embodiment> (Configuration) The control of the gas engine 100 during load shedding according to the first embodiment will be described below with reference to Figures 1 to 4. Figure 1 shows an example of the schematic equipment configuration of the gas engine 100. The gas engine 100 includes a fuel supply system L0, a vent line L1, and an engine body E, the engine body E being equipped with a cylinder, piston, crankshaft, etc. (not shown). The fuel supply system L0 is equipped with an electronic valve V0, a ​​pressure sensor C0, a fuel injector I1, and a pressure sensor C1 in order from the upstream side in the direction of gas fuel flow. High-pressure gas fuel is supplied to the fuel supply system L0, the pressure of the gas fuel is adjusted by the electronic valve V0, and the flow rate of gas fuel supplied to the cylinder is adjusted by the fuel injector I1. One end of the vent line L1 is connected to a position between the electronic valve V0 and the fuel injector I1 of the fuel supply system L0. The other end of the vent line L1 is open to the atmosphere. The vent valve V1 is provided on the vent line L1. Normally, the vent valve V1 is closed.

[0014] The control device 10 controls the electronic valve V0, the fuel injector I1, the vent valve V1, the crankshaft of the engine body E, etc. For example, the control device 10 acquires the pressure measured by pressure sensors C0 and C1, subtracts the pressure P1 measured by pressure sensor C1 from the pressure P measured by pressure sensor C0 to calculate the differential pressure between the upstream and downstream sides of the fuel injector I1, and feedback controls the opening degree of the electronic valve V0 so that the calculated differential pressure becomes a predetermined target differential pressure. The control device 10 controls the flow rate of gas fuel injected by the fuel injector I1 according to the output of the gas engine 100. The control device 10 ignites the gas fuel (or a mixture with air) to rotate the crankshaft of the engine body E, causing the piston to reciprocate and drive the gas engine 100. When the load is cut off, the control device 10 opens the vent valve V1 and discharges the gas fuel out of the system to avoid an excessive pressure rise.

[0015] After opening the vent valve V1 when the load is cut off, the control device 10 opens the vent valve V1 again after a while, depending on the elapsed time since the vent valve V1 was opened and the pressure measured by the pressure sensor C0. If the opening degree of the electronic valve V0 is kept under feedback control at this time, a response delay will occur, causing the pressure downstream of the electronic valve V0 to rise excessively. Therefore, in this embodiment, when the vent valve V1 is opened or closed when the load is cut off, at the timing of closing the vent valve V1, the opening degree of the electronic valve V0 is changed to a degree corresponding to the output after the load is cut off (this opening degree is smaller than the opening degree before the vent valve V1 was closed), and it is fixed at that opening degree for a while. This control is called opening degree fixed control. The control device 10 then monitors the pressure P measured by the pressure sensor C0 and terminates the opening degree fixed control according to the pressure P of the gas fuel downstream of the electronic valve V0.

[0016] (Fixed Opening Control 1) Figure 2 shows an example of fixed opening control. The vertical axis of Figure 2 shows the pressure P of the gas fuel downstream of the electronic valve V0 measured by the pressure sensor C0 and the opening degree of the electronic valve V0, and the horizontal axis shows time. Graph 21 shows the change in pressure P, and graph 22 shows the change in the opening degree of the electronic valve V0. When a load shutoff signal indicating the occurrence of load shutoff is acquired at time T0, the control device 10 opens the vent valve V1. Then, at time T1, the control device 10 closes the vent valve V1 and, at the same time, fixes the opening degree of the electronic valve V0 to an opening degree corresponding to the output after load shutoff. For example, the control device 10 is equipped with an opening degree setting table that associates the output of the gas engine 100 with the opening degree of the electronic valve V0. For example, the load shutoff signal includes the output after load shutoff. The control device 10 obtains the opening degree of the electronic valve V0 corresponding to the output after load removal by referring to the opening degree setting table, stops the feedback control up to that point, and fixes the opening degree of the electronic valve V0 to the opening degree corresponding to the output (opening degree fixed control). The control device 10 continues to monitor the pressure P measured by the pressure sensor C0. At time T2, when the pressure P falls below a predetermined threshold, the control device 10 terminates the opening degree fixed control and returns to the opening degree control of the electronic valve V0 by feedback control. By closing the vent valve V1 and simultaneously forcibly narrowing the opening degree of the electronic valve V0 to a fixed value, even if the responsiveness of the electronic valve V0 is poor, it is possible to suppress an excessive pressure rise downstream of the electronic valve V0 after the vent valve V1 is closed.

[0017] Figure 3 shows another example of fixed-opening control. The meaning of the vertical and horizontal axes in Figure 3 is the same as in Figure 2. Graph 31 shows the change in pressure P, and graph 32 shows the change in the opening degree of the electronic valve V0. When a load cutoff signal is received at time T0, the control device 10 opens the vent valve V1, and at time T1, closes the vent valve V1 and fixes the opening degree of the electronic valve V0 to an opening degree corresponding to the output after load cutoff (fixed-opening control). The pressure P measured by the pressure sensor C0 rises for a while, and then gradually decreases after reaching a peak. The control device 10 receives the pressure P measured by the pressure sensor C0 and monitors the change in pressure P. When the pressure P begins to decrease at time T2', the control device 10 terminates the fixed-opening control and returns to feedback control of the opening degree of the electronic valve V0. For example, the control device 10 may store the time-series pressure P after the vent valve V1 is closed, and when it acquires a pressure P that has fallen by a predetermined value or more from the maximum value among the stored pressures P, it may determine that the pressure P has begun to decrease. In this way, similar to the control in Figure 2, it is possible to suppress an excessive pressure rise downstream of the electronic valve V0 after the vent valve V1 is closed.

[0018] (Operation) Figure 4 is a flowchart showing an example of control during load shedding according to the first embodiment. The control device 10 acquires a load shedding signal (step S1). Upon acquiring the load shedding signal, the control device 10 immediately opens the vent valve V1 (step S2). Next, when predetermined conditions are met (for example, a predetermined time has elapsed since the vent valve V1 was opened, or the pressure P measured by the pressure sensor C0 reaches a predetermined value), the control device 10 closes the vent valve V1 and performs opening degree fixing control to fix the opening degree of the electronic valve V0 to a value corresponding to the output of the gas engine 100 after load shedding (step S3). Next, when the pressure P measured by the pressure sensor C0 satisfies predetermined conditions, the control device 10 terminates the opening degree fixing control of the electronic valve V0 (step S4). For example, the control device 10 terminates the opening degree fixing control when the pressure P falls below a predetermined threshold (Figure 2). Alternatively, the control device 10 terminates the opening degree fixing control when the pressure P changes from rising to falling (Figure 3).

[0019] (Effects) As described above, according to the first embodiment, the vent valve V1 that was opened when the load was cut off is closed, and at the same time, the electronic valve V0 is controlled with an opening degree corresponding to the output of the gas engine 100 after the load was cut off. As a result, even if the responsiveness of the electronic valve V0 is poor, the electronic valve V0 can be narrowed compared to before the vent valve V1 was closed, so that an excessive pressure rise downstream of the electronic valve V0 can be suppressed compared to conventional control.

[0020] <Second Embodiment> (Configuration) The control after load shedding according to the second embodiment will be described below with reference to Figures 5 to 7. In the first embodiment, the opening degree of the electronic valve V0 was fixed at the timing of closing the vent valve V1. In contrast, in the second embodiment, pressure rise is dealt with while continuing to control the opening degree by feedback control.

[0021] Figure 5 is the first diagram illustrating the control during load shedding according to the second embodiment. The control device 10 adjusts the opening degree of the electronic valve V0 by PI control or PID control so that the difference between the pressure P measured by pressure sensor C0 and the pressure P1 measured by pressure sensor C1 approaches the target differential pressure. Figure 5 is a schematic diagram of the control logic when the control device 10 calculates the opening degree command value of the electronic valve V0 by PID control. The control logic includes a proportional term 51, a differential term 52, and an integral term 53 of the PID control. In the second embodiment, at the timing of closing the vent valve V1 which was opened by load shedding, the control device 10 overwrites the integral term 53 so that the output by PID control, that is, the opening degree command value of the electronic valve V0, becomes an opening degree corresponding to the output of the gas engine 100 after load shedding. For example, the control device 10 has an opening degree setting table that associates the output of the gas engine 100 with the opening degree of the electronic valve V0, and obtains an opening degree corresponding to the output after load shedding by referring to this opening degree setting table. This opening degree is Y ＴＡＲＧＥＴ Let Y be the opening degree of the electronic valve V0 at time T1 when the vent valve is closed. Ｔ１ The control device 10 closes the vent valve V1, and the opening degree of the electronic valve V0 at time T1 is Y ＴＡＲＧＥＴ The value of the integral term 53 is obtained from the value of the integral term 53 calculated by PID control (Y Ｔ１ -YＴＡＲＧＥＴ The value obtained by subtracting ) is rewritten. This makes the opening command value of the electronic valve V0 Y ＴＡＲＧＥＴ The same applies when the control device 10 controls the opening degree of the electronic valve V0 by PI control.

[0022] Figure 6 shows the changes in pressure P and the opening degree of the electronic valve V0 during load shedding according to the second embodiment. Graph 61 shows the changes in pressure P, and graph 62 shows the changes in the opening degree of the electronic valve V0. When the control device 10 receives a load shedding signal at time T0, it opens the vent valve V1. Next, at time T1, the control device 10 closes the vent valve V1 and opens it to an opening degree Y corresponding to the output after load shedding. ＴＡＲＧＥＴ The value of the integral term 53 of the PID control or PI control is overwritten so that it matches the opening command value for the electronic valve V0. After time T1, the opening of the electronic valve V0 is adjusted by PID control or PI control as before so that the pressure difference between the gas fuel on the upstream and downstream sides of the fuel injector I1 becomes the target differential pressure. This makes it possible to suppress an excessive pressure rise after the vent valve V1 is closed.

[0023] (Operation) Figure 7 is a flowchart showing an example of control during load shedding according to the second embodiment. The control device 10 acquires a load shedding signal (step S11). Upon acquiring the load shedding signal, the control device 10 immediately opens the vent valve V1 (step S12). Next, when predetermined conditions are met (for example, a predetermined time has elapsed since the vent valve V1 was opened, the pressure P measured by the pressure sensor C0 reaches a predetermined value, etc.), the control device 10 closes the vent valve V1 and rewrites the integral term 53 of the PID control or PI control so that the opening degree of the electronic valve V0 corresponds to the output after load shedding (step S13). After closing the vent valve V1 and rewriting the integral term 53 only once, the control device 10 performs PID control or PI control so that the differential pressure between the pressure P measured by the pressure sensor C0 and the pressure P1 measured by the pressure sensor C1 becomes the target differential pressure, and controls the opening degree of the electronic valve V0.

[0024] (Effects) As described above, according to the second embodiment, when the load is cut off, the vent valve V1 that was opened is closed, and at the same time the integral term 53 of the PID control or PI control is rewritten, the electronic valve V0 is controlled with an opening degree corresponding to the output of the gas engine 100 after the load is cut off. As a result, even if the responsiveness of the electronic valve V0 is poor, the electronic valve V0 can be narrowed compared to before the vent valve V1 was closed, so that an excessive pressure rise downstream of the electronic valve V0 can be suppressed compared to conventional control.

[0025] <Third Embodiment> (Configuration) The control after load shedding according to the third embodiment will be described below with reference to Figures 8 to 9. In the first and second embodiments, the opening degree of the electronic valve V0 was controlled to an opening degree corresponding to the output at the timing of closing the vent valve V1. In contrast, the third embodiment controls the opening degree of the vent valve V1. The third embodiment assumes that the vent valve V1 is a valve whose opening degree can be controlled. The third embodiment may be executed alone when the load is shedding, or the first or second embodiment and the third embodiment may be executed in combination.

[0026] Figure 8 illustrates the control during load shedding according to the third embodiment. In Figure 8, the vertical axis represents the opening degree of the vent valve V1, and the horizontal axis represents time. When the control device 10 receives a load shedding signal at time T0, it sets the opening degree of the vent valve V1 to 100%. When the predetermined conditions are met at time T1, the control device 10 closes the vent valve V1, but at this time, it gradually decreases the opening degree of the vent valve V1 from 100% (for example, in a ramp shape). By gradually decreasing the opening degree of the vent valve V1 from 100% and closing it, the change in the flow rate of the gas fuel passing through the vent valve V1 becomes gradual when the vent valve V1 is closed, and as a result, the opening degree control of the electronic valve V0 can keep up more easily. This makes it possible to suppress an excessive pressure rise on the downstream side of the electronic valve V0 after the vent valve V1 is closed during load shedding.

[0027] (Operation) Figure 9 is a flowchart showing an example of control during load shedding according to the third embodiment. The control device 10 acquires a load shedding signal (step S21). Upon acquiring the load shedding signal, the control device 10 immediately opens the vent valve V1 (step S22). The control device 10 sets the opening of the vent valve V1 to 100%. Next, when predetermined conditions are met (for example, a predetermined time has elapsed since the vent valve V1 was opened, the pressure P measured by the pressure sensor C0 reaches a predetermined value, etc.), the control device 10 gradually decreases the opening of the vent valve V1 (step S23). For example, the control device 10 decreases the opening of the vent valve V1 so that the opening of the vent valve V1 decreases in a ramp-like manner. When the opening of the vent valve V1 becomes 0%, the control after load shedding is terminated.

[0028] Regarding the control of the electronic valve V0 from step S23 onward, it may be controlled so that the differential pressure of the gas fuel on the upstream and downstream sides of the fuel injector I1 becomes a target differential pressure, or it may be controlled in the same manner as in the first or second embodiment. By combining the first or second embodiment with the third embodiment, it is expected that the pressure rise on the upstream side of the fuel injector I1 can be further suppressed compared to when they are implemented individually.

[0029] In the above explanation, for example, the vent valve V1 is started to close when a predetermined time has elapsed since it was opened, or when the pressure P measured by the pressure sensor C0 reaches a predetermined value. However, the vent valve V1 may be started to close a little earlier so that its opening degree becomes 0% around the time these conditions are met.

[0030] (Effects) As described above, according to the third embodiment, the vent valve V1, which is open to 100% when the load is removed, is gradually closed. This makes it possible to suppress an excessive pressure rise downstream of the electronic valve V0 after the vent valve V1 is closed.

[0031] Figure 10 is a schematic block diagram showing the hardware configuration of a control device according to an embodiment. The computer 90 includes a processor 91, main memory 92, storage 93, and interface 94. The control device 10 described above is implemented in the computer 90. The operation of each of the above-described processing units is stored in the storage 93 in the form of a program. The processor 91 reads the program from the storage 93, loads it into the main memory 92, and executes the above processing according to the program. The processor 91 allocates storage areas in the main memory 92 corresponding to each of the above-described storage units according to the program. Examples of the processor 91 include a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), and a microprocessor.

[0032] The program may be for implementing some of the functions that the computer 90 is to perform. For example, the program may perform functions in combination with other programs already stored in storage, or in combination with other programs implemented in other devices. In other embodiments, the computer 90 may include, in addition to or instead of the above configuration, a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device). Examples of PLDs include PAL (Programmable Array Logic), GAL (Generic Array Logic), CPLD (Complex Programmable Logic Device), and FPGA (Field Programmable Gate Array). In this case, some or all of the functions implemented by the processor 91 may be implemented by the integrated circuit. Such an integrated circuit is also included as an example of a processor.

[0033] Examples of storage 93 include HDDs (Hard Disk Drives), SSDs (Solid State Drives), magnetic disks, magneto-optical disks, CD-ROMs (Compact Disc Read Only Memory), DVD-ROMs (Digital Versatile Disc Read Only Memory), and semiconductor memory. Storage 93 may be an internal medium directly connected to the bus of the computer 90, or an external medium connected to the computer 90 via an interface 94 or a communication line. When this program is delivered to the computer 90 via a communication line, the computer 90 that receives the delivery may expand the program into the main memory 92 and execute the above processing. In at least one embodiment, storage 93 is a tangible storage medium that is not temporary. The program may be for realizing some of the functions described above. Furthermore, the program may be a so-called differential file (differential program) that realizes the functions described above in combination with other programs already stored in storage 93.

[0034] As described above, several embodiments relating to this disclosure have been explained, but all of these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents.

[0035] <Note> The control device, gas engine, control method, and program described in each embodiment can be understood, for example, as follows.

[0036] (1) The control device according to the first embodiment is an engine including a fuel supply system that supplies fuel to the engine, a valve provided in the fuel supply system, a fuel injection device that adjusts the flow rate of the fuel downstream of the valve, a vent line having one end connected between the valve and the fuel injection device in the fuel supply system and the other end open to the atmosphere, and a vent valve provided in the vent line, wherein the control device includes means for opening the vent valve when a load cutoff occurs, and means for closing the vent valve after it has been opened and controlling the opening degree of the valve to a post-load cutoff opening degree which is an opening degree corresponding to the output of the engine after the load cutoff. This makes it possible to suppress the pressure rise downstream of the electronic valve when the vent valve that was opened during a load cutoff is closed.

[0037] (2) The control device according to the second embodiment is the control device according to (1), wherein the controlling means closes the vent valve and controls the opening degree of the valve to the opening degree after load removal, and fixes the opening degree to the opening degree after load removal for a predetermined period of time. This makes it possible to suppress the pressure rise downstream of the electronic valve when the vent valve that was opened when the load was removed is closed.

[0038] (3) The control device according to the third embodiment is the control device according to (2), wherein the predetermined period is the period from when the opening of the valve is controlled to the opening after load cutoff until the pressure of the fuel between the valve and the fuel injector falls below a predetermined threshold. This makes it possible to suppress the pressure rise downstream of the electronic valve when the vent valve that was opened during load cutoff is closed.

[0039] (4) The control device according to the fourth embodiment is the control device according to (2), wherein the predetermined period is the period from when the opening of the valve is controlled to the opening after load cutoff until the pressure of the fuel between the valve and the fuel injector changes from rising to falling. This makes it possible to suppress the pressure rise downstream of the electronic valve when the vent valve that was opened during load cutoff is closed.

[0040] (5) The control device according to the fifth aspect is the control device of (1), wherein the means for controlling controls the opening degree of the valve by PI control or PID control, closes the vent valve, and sets the value of the integral term of the PI control or the PID control so that the opening degree of the valve becomes the opening degree after load interruption. Thereby, it is possible to suppress the pressure increase downstream of the electronic valve when the vent valve opened during load interruption is closed.

[0041] (6) The control device according to the sixth aspect is the control device of (5), wherein when the opening degree of the valve when closing the vent valve is taken as the first opening degree, the means for controlling rewrites the output of the integral term to a value obtained by subtracting (the first opening degree - the opening degree after load interruption) from the output. Thereby, the opening degree of the electronic valve can be quickly controlled to the opening degree corresponding to the output after load interruption.

[0042] (7) The control device according to the seventh aspect is the control device of (5) to (6), wherein the means for controlling performs the PI control or the PID control without rewriting the value of the integral term after once rewriting the value of the integral term. Thereby, the differential pressure between the fuel upstream and downstream of the fuel injection device can be controlled to the target differential pressure.

[0043] (8) The control device according to the eighth aspect is the control device of (1) to (7), wherein the means for controlling decreases the opening degree of the vent valve in a ramp shape when closing the vent valve. Thereby, it is possible to gently increase the pressure downstream of the electronic valve when the vent valve opened during load interruption is closed.

[0044] (9) The control device according to the ninth aspect includes a fuel supply system that supplies fuel to an engine, a valve provided in the fuel supply system, a fuel injection device that adjusts the flow rate of the fuel downstream of the valve, a vent line having one end connected between the valve and the fuel injection device in the fuel supply system and the other end open to the atmosphere, and a vent valve provided in the vent line. In the engine, means for opening the vent valve when a load cut occurs and means for closing the vent valve after opening the vent valve are provided. The closing means decreases the opening degree of the vent valve in a ramp shape when closing the vent valve. Thereby, it is possible to suppress an increase in pressure downstream of the electronic valve when closing the vent valve opened during load cut.

[0045] (10) The gas engine according to the tenth aspect includes a fuel supply system that supplies gas fuel to an engine, a valve provided in the fuel supply system, a fuel injection device that adjusts the flow rate of the gas fuel downstream of the valve, a vent line having one end connected between the valve and the fuel injection device in the fuel supply system and the other end open to the atmosphere, a vent valve provided in the vent line, and the control device according to (1) to (9). Thereby, it is possible to suppress an increase in pressure downstream of the electronic valve when closing the vent valve opened during load cut.

[0046] (11) The control method according to the eleventh aspect is applicable to an engine including a fuel supply system that supplies fuel to an engine, a valve provided in the fuel supply system, a fuel injection device that adjusts the flow rate of the fuel downstream of the valve, a vent line having one end connected between the valve and the fuel injection device in the fuel supply system and the other end open to the atmosphere, and a vent valve provided in the vent line. When a load cut occurs, the vent valve is opened, the vent valve is closed after opening the vent valve, and the opening degree of the valve is controlled to an opening degree after load cut that is an opening degree corresponding to the output of the engine after the load cut.

[0047] (12) The program according to the twelfth embodiment causes a computer to perform a process in an engine including a fuel supply system for supplying fuel to an engine, a valve provided in the fuel supply system, a fuel injection device for adjusting the flow rate of the fuel downstream of the valve, a vent line having one end connected between the valve and the fuel injection device in the fuel supply system and the other end open to the atmosphere, and a vent valve provided in the vent line, wherein when a load cutoff occurs, the computer opens the vent valve, closes the vent valve after it has been opened, and controls the opening degree of the valve to a post-load cutoff opening degree which is an opening degree corresponding to the output of the engine after the load cutoff.

[0048] According to the control device, gas engine, control method, and program described above, it is possible to suppress the pressure rise downstream of the electronic valve when the vent valve, which was opened when the load was cut off, is closed.

[0049] C0, C1... Pressure sensors E... Engine body I1... Fuel injection system L0... Fuel supply system L1... Vent line V0... Electronic valve V1... Vent valve 10... Control unit 90... Computer 91... Processor 92... Main memory 93... Storage 94... Interface 100... Gas engine

Claims

An engine comprising: a fuel supply system for supplying fuel to the engine; a valve provided in the fuel supply system; a fuel injection device for adjusting the flow rate of the fuel downstream of the valve; a vent line, one end of which is connected between the valve and the fuel injection device in the fuel supply system and the other end of which is open to the atmosphere; and a vent valve provided in the vent line, A means for opening the vent valve when a load shedding occurs, A means for closing the vent valve after it has been opened, and controlling the valve opening to a post-load-off opening that corresponds to the engine output after the load has been cut off, A control device equipped with the following features. 　 The control means closes the vent valve and controls the valve opening to the opening after load removal, and fixes the opening to the opening after load removal for a predetermined period of time. The control device according to claim 1. 　 The predetermined period is the period from when the valve opening is controlled to the load-off opening until the fuel pressure between the valve and the fuel injector falls below a predetermined threshold. The control device according to claim 2. 　 The predetermined period is the period from when the valve opening is controlled to the load-shelter opening until the fuel pressure between the valve and the fuel injector changes from rising to falling. The control device according to claim 2. 　 The control means controls the opening degree of the valve by PI control or PID control. The vent valve is closed, and the value of the integral term of the PI control or PID control is rewritten so that the valve opening becomes the opening after load removal. The control device according to claim 1. 　 The control means, when the opening degree of the valve when the vent valve is closed is defined as the first opening degree, rewrites the value of the integral term to a value obtained by subtracting (the first opening degree - the opening degree after load cutoff) from that value. The control device according to claim 5. 　 The control means, after rewriting the value of the integral term once, performs the PI control or PID control without rewriting the value of the integral term. The control device according to claim 5. 　 The control means, when closing the vent valve, reduces the opening degree of the vent valve in a ramp-like manner. The control device according to claim 1 or claim 2. 　 An engine comprising: a fuel supply system for supplying fuel to the engine; a valve provided in the fuel supply system; a fuel injection device for adjusting the flow rate of the fuel downstream of the valve; a vent line, one end of which is connected between the valve and the fuel injection device in the fuel supply system and the other end of which is open to the atmosphere; and a vent valve provided in the vent line, A means for opening the vent valve when a load shedding occurs, A means for closing the vent valve after it has been opened, Equipped with, The closing means reduces the opening degree of the vent valve in a ramp-like manner when closing the vent valve. Control device. 　 A fuel supply system that supplies gaseous fuel to the engine, A valve provided in the fuel supply system, A fuel injection device that adjusts the flow rate of the gas fuel downstream of the valve, A vent line having one end connected between the valve and the fuel injection device in the fuel supply system and the other end open to the atmosphere, A vent valve provided in the aforementioned vent line, A control device according to claim 1 or claim 2, A gas engine equipped with a gas engine. 　 An engine comprising: a fuel supply system for supplying fuel to the engine; a valve provided in the fuel supply system; a fuel injection device for adjusting the flow rate of the fuel downstream of the valve; a vent line having one end connected between the valve and the fuel injection device in the fuel supply system and the other end open to the atmosphere; and a vent valve provided in the vent line, When a load shedding occurs, the vent valve opens, After opening the vent valve, the vent valve is closed, and the opening degree of the valve is controlled to a post-load-off opening degree that corresponds to the engine output after the load is cut off. Control method. 　 On the computer, An engine comprising: a fuel supply system for supplying fuel to the engine; a valve provided in the fuel supply system; a fuel injection device for adjusting the flow rate of the fuel downstream of the valve; a vent line having one end connected between the valve and the fuel injection device in the fuel supply system and the other end open to the atmosphere; and a vent valve provided in the vent line, When a load shedding occurs, the vent valve opens, A process to close the vent valve after opening it, and to control the valve opening to a post-load-off opening that corresponds to the engine output after the load is cut off. A program that executes the command.

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