JP2016070245A - Fuel injection control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection control device of an internal combustion engine capable of properly executing a processing for resolving an abnormality when the abnormality in valve opening is found on a gas injection valve.SOLUTION: A control device of an engine applied to a fuel injection system including a gas injection valve 21 injecting a gas fuel to an engine 10, and a pressure sensor 38 detecting a pressure of the gas fuel in a gas fuel supply passage to the gas injection valve 21, generates a first drive signal of the gas injection valve 21 according to a requested injection amount calculated according to an operating state of the engine 10, and executes fuel injection by outputting the first drive signal. In a case when the difference between a first pre-drive pressure as a detection value of a pressure before the output of the first drive signal and a first after-drive pressure as a detection value of a pressure after the output of the first drive signal is less than a prescribed threshold value, an abnormality in valve opening in which the gas injection valve 21 is not opened, is determined, and a second drive signal generated regardless of the requested injection amount, is output to the gas injection valve 21.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fuel injection control device for an internal combustion engine.

  An internal combustion engine in which gas fuel such as compressed natural gas (CNG) is burned has been put into practical use. In such an internal combustion engine, a fuel supply system configured to supply gas fuel to the gas injection valve is provided in the middle of a gas tank that stores the gas fuel in a high pressure state and a fuel pipe that connects the gas tank and the injection valve. A pressure regulating valve that adjusts the pressure of the gas fuel to be reduced, and an electromagnetically driven shut-off valve that is provided upstream of the pressure regulating valve (that is, on the gas tank side) and blocks the flow of the gas fuel to the pressure regulating valve; There is a known configuration comprising:

  By the way, in an internal combustion engine using gas fuel, the viscosity of the oil component (mixed by the compressor of the gas stand equipment) increases in the gas fuel when the temperature is low, or in the methane gas contained in the gas fuel. Due to freezing of moisture or moisture generated during combustion, there may be a valve opening abnormality in which the gas injection valve does not open normally at the injection timing of the gas injection valve.

  Therefore, in Patent Document 1, when there is a possibility that the valve opening abnormality may occur in the gas injection valve based on the detection results of the engine water temperature, the intake air temperature, and the gas temperature, the energization amount to the gas injection valve is increased. Further, the elimination of the valve opening abnormality is promoted (see, for example, Patent Document 1).

JP-A-8-144859

  However, in the low temperature state, the valve opening abnormality does not always occur uniformly in the gas injection valve. Further, the abnormality of the gas injection valve opening may also be caused by foreign matter or the like adhering to the gas injection valve. In Patent Document 1, these points are not considered. Therefore, in order to more appropriately perform the process for eliminating the valve opening abnormality when the gas injection valve has the valve opening abnormality while improving the accuracy of determining the gas injection valve opening abnormality, It can be said that there is room.

  The present invention has been made in view of the above, and it is a main object of the present invention to provide a fuel injection control device for an internal combustion engine that can appropriately perform a process of prompting the elimination of the abnormality when the gas injection valve has a valve opening abnormality. Objective.

  The present invention comprises a gas injection valve (21) for injecting gas fuel in an internal combustion engine (10), a pressure detection means (38) for detecting the pressure of the gas fuel in the supply path of gas fuel to the gas injection valve, The first drive signal of the gas injection valve is generated according to the required injection amount calculated according to the operating state of the internal combustion engine, and fuel injection is performed by the output of the first drive signal The fuel injection control means for performing the operation, the first pre-drive pressure that is a detected value of the pressure before the output of the first drive signal, and the post-first drive that is the detected value of the pressure after the output of the first drive signal When the difference from the pressure is less than a predetermined threshold, it is determined that a valve opening abnormality that does not open the gas injection valve occurs, and the generated second drive signal is output to the gas injection valve regardless of the required injection amount. Second drive signal raw Characterized in that it comprises a means.

  According to the present invention, the pressure change before and after outputting the first drive signal generated based on the required injection amount is acquired, and when the pressure change is less than a predetermined threshold, the gas injection valve has a valve opening abnormality. The generated second drive signal is output regardless of the required injection amount. In this case, the abnormality determination is performed using the gas pressure change directly related to the driving of the gas injection valve, so that the valve opening abnormality can be accurately determined. Moreover, when there is a valve opening abnormality in the gas injection valve, it is possible to appropriately perform processing for prompting the cancellation.

1 is a schematic configuration diagram of a fuel injection system. The flowchart of a valve opening abnormality determination process. The timing chart of a valve opening abnormality determination process.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings. The present embodiment is applied to a so-called bi-fuel type on-vehicle multi-cylinder engine (multi-cylinder internal combustion engine) that uses compressed natural gas (CNG) as a gas fuel and gasoline as a liquid fuel as combustion fuel. It is supposed to be embodied as a fuel injection system. An overall schematic diagram of this system is shown in FIG.

  An engine 10 shown in FIG. 1 is an inline three-cylinder spark ignition gas engine, and an intake system 11 and an exhaust system 12 are connected to an intake port and an exhaust port, respectively. The intake system 11 has an intake manifold 13 and an intake pipe 14. The intake manifold 13 has a plurality of (for the number of cylinders of the engine 10) branch pipe portions 13a connected to the intake port of the engine 10, and a collective portion 13b connected to the intake pipe 14 on the upstream side. ing. The branch pipe portion 13a corresponds to a cylinder-specific intake passage. The intake pipe 14 is provided with a throttle valve 15 as air amount adjusting means. The throttle valve 15 is configured as an electronically controlled throttle valve whose opening degree is adjusted by a throttle actuator 15a such as a DC motor. The opening degree of the throttle valve 15 (throttle opening degree) is a throttle opening degree built in the throttle actuator 15a. It is detected by the degree sensor 15b.

  Further, the exhaust system 12 has an exhaust manifold 16 and an exhaust pipe 17. The exhaust manifold 16 has a plurality of (for the number of cylinders of the engine 10) branch pipe portions 16a connected to the exhaust port of the engine 10 and a collecting portion 16b connected to the exhaust pipe 17 on the downstream side. ing. The exhaust pipe 17 is provided with an exhaust sensor 18 for detecting exhaust components and a catalyst 19 for purifying exhaust. Specifically, an air-fuel ratio sensor that detects the air-fuel ratio from the oxygen concentration in the exhaust is provided as the exhaust sensor 18.

  A spark plug 20 is provided in each cylinder (# 1 to # 3) of the engine 10. A high voltage is applied to the ignition plug 20 at a desired ignition timing through an ignition device 20a including an ignition coil. By applying this high voltage, a spark discharge is generated between the opposing electrodes of each spark plug 20, and the fuel introduced into the cylinder (combustion chamber) is ignited and used for combustion.

  Further, the present system is a fuel injection means for injecting and supplying fuel to the engine 10, and a gas fuel supply unit 30 for injecting gas fuel (CNG fuel) to the gas injection valve 21 and a liquid injection valve 74. And a liquid fuel supply unit 70 for supplying liquid fuel.

  In the gas fuel supply unit 30, the gas injection valve 21 injects gas fuel into the branch pipe portion 13 a of the intake manifold 13 in the intake system 11, and the gas fuel is injected into each cylinder by the injection of the gas injection valve 21. Supplied to the port.

  The gas injection valve 21 is an open / close type control valve in which the valve body is lifted from the closed position to the open position by being electrically driven by the power of the battery 50, and is an on / off type input from the control unit 40. Are driven to open by the drive signal (valve opening drive signal). The gas injection valve 21 opens when the drive signal is on, and closes when the drive signal is off. An amount of gas fuel corresponding to the time for which the drive signal is turned on is injected.

  A fuel conduit 22 is connected to the tip of the gas injection valve 21. The other end side of the fuel conduit 22 is connected to a branch pipe portion 13a as an intake portion. Thereby, the gas fuel injected from the gas injection valve 21 is discharged to the branch pipe portion 13a through the fuel conduit 22. Note that each cylinder and the gas injection valve 21 may be directly connected without providing the configuration of the fuel conduit 22.

  A gas tank 32 is connected to the gas injection valve 21 via a gas pipe 31, and in the middle of the gas pipe 31, there is a pressure adjustment function for adjusting the pressure of the gas fuel supplied to the gas injection valve 21. A regulator 33 is provided.

  The regulator 33 adjusts the gas fuel stored in the gas tank 32 in a high pressure state (for example, a maximum of 20 MPa) to a predetermined set pressure (for example, 0.2 to 1.0 MPa) that is an injection pressure of the gas injection valve 21. The gas fuel after the pressure reduction adjustment is supplied to the gas injection valve 21 through the gas pipe 31. In the gas pipe 31, the upstream side of the regulator 33 is a high-pressure pipe part 31a that forms a high-pressure side passage, and the downstream side is a low-pressure pipe part 31b that forms a low-pressure side passage.

  The gas fuel passage formed by the gas pipe 31 and the like further includes a tank main stop valve 34 disposed in the vicinity of the fuel outlet of the gas tank 32, and a fuel downstream of the tank main stop valve 34 and in the regulator 33. A shutoff valve 35 is provided in the vicinity of the inlet, and the flow of gas fuel in the gas pipe 31 is allowed and shut off by these valves 34 and 35. Both the tank main stop valve 34 and the shutoff valve 35 are electromagnetic on-off valves, and are normally closed types that shut off the flow of gas fuel when not energized and allow the gas fuel to flow when energized.

  In the gas pipe 31, a pressure sensor 36 for detecting the fuel pressure and a temperature sensor 37 for detecting the fuel temperature are provided in the high-pressure pipe portion 31a. The low pressure pipe section 31b is provided with a pressure sensor 38 for detecting the fuel pressure and a temperature sensor 39 for detecting the fuel temperature. Note that the shut-off valve 35 and the pressure sensor 36 can be provided integrally with the regulator 33. In this embodiment, a configuration in which the shut-off valve 35 and the pressure sensor 36 are provided integrally with the regulator 33 is employed.

  On the other hand, in the liquid fuel supply unit 70, a fuel tank 72 is connected to the liquid injection valve 74 via a fuel conduit 71. The fuel conduit 71 is provided with a fuel pump 73 for feeding the liquid fuel in the fuel tank 72 to the liquid injection valve 74.

  The control unit 40 includes a CPU 41, ROM 42, RAM 43, backup RAM 44, interface 45, and bidirectional bus 46, and the CPU 41, ROM 42, RAM 43, backup RAM 44, and interface 45 are connected to each other by a bidirectional bus 46.

  The CPU 41 executes a routine (program) for controlling the operation of each unit in this system. The ROM 42 stores in advance various data such as a routine executed by the CPU 41, maps (including tables, relational expressions, and the like), parameters, and the like referred to when the routine is executed. The RAM 43 temporarily stores data as necessary when the CPU 41 executes a routine. The backup RAM 44 stores data as appropriate under the control of the CPU 41 with the battery 50 powered on, and retains the stored data even after the power is shut off.

  The interface 45 includes sensors (crank angle sensor, air flow meter, cooling water temperature sensor, etc.) provided in the present system, including the throttle opening sensor 15b, the exhaust sensor 18, the pressure sensors 36, 38, and the temperature sensors 37, 39 described above. A vehicle speed sensor or the like), and outputs (detection signals) from these sensors to the CPU 41. The interface 45 is electrically connected to driving units such as the throttle actuator 15a, the ignition device 20a, the gas injection valve 21, the tank main stop valve 34, the shutoff valve 35, and the like, in order to drive these driving units. The drive signal sent from the CPU 41 is output toward the drive unit.

  That is, the control unit 40 acquires the operating state of the engine 10 based on the output signals of the above-described sensors, and controls the above-described driving unit based on this operating state. Supplementing the fuel injection control, the control unit 40 calculates the required injection amount of the fuel injection by the gas injection valve 21 based on the engine operating state, generates a first drive signal based on the required injection amount, and the first drive signal. The fuel injection is performed by driving the gas injection valve 21 by the drive signal.

  By the way, in an internal combustion engine that uses gas fuel, the gas injection valve is operated at an injection timing due to freezing of moisture in methane gas contained in the gas fuel or moisture generated during combustion in a low temperature state. There is a risk that the valve will not open correctly. In particular, when starting use of the gas injection valve 21 from a rest state, such as when the engine is started or when switching from liquid fuel to gas fuel, there is a high possibility that such valve opening abnormality will occur. Further, abnormal opening of the gas injection valve can also be caused by adhesion of deposits such as oil components to the gas injection valve.

  Therefore, the control unit 40 of the present embodiment detects the pressure upstream of the gas injection valve 21 from the pressure sensor 38 before and after the output of the first drive signal for each gas injection valve 21. And the valve opening abnormality of each gas injection valve 21 is detected separately using the pressure change before and after the output of the first drive signal.

  Further, for the gas injection valve 21 having the valve opening abnormality, valve opening assist driving for eliminating the valve opening abnormality of the gas injection valve 21 is performed. In the valve opening assist drive, after the first drive signal generated based on the required injection amount is output, the second drive signal generated regardless of the required injection amount is output. Thus, by increasing the drive amount of the gas injection valve 21, it is possible to promote the elimination of the valve opening abnormality of the gas injection valve 21. Further, when outputting the second drive signal, a pressure change before and after the output is detected. Then, when a pressure change occurs before and after the output of the second drive signal, the output of the second drive signal is stopped. Thereby, opening of the gas injection valve 21 can be assisted while suppressing a decrease in fuel consumption.

  Next, the drive process of the gas injection valve 21 which the control part 40 of this embodiment implements is demonstrated using FIG. Note that the following processing is repeatedly performed by the control unit 40 at a predetermined cycle when fuel injection by gas fuel is selected.

  In FIG. 2, it is determined whether or not it is time to acquire pressure before the injection of gas fuel in each cylinder (S11). When a positive determination is made, the pressure on the upstream side of the gas injection valve 21 is acquired as the pre-drive pressure Pa (first pre-drive pressure) (S12). Thereafter, the first drive signal is output based on the required injection amount.

  If a negative determination is made in S11, it is determined whether or not it is time to acquire pressure after the injection of gas fuel (S13). For example, an affirmative determination is made when the predetermined mask period has elapsed since the first drive signal was output. In this case, the pressure on the upstream side of the gas injection valve 21 is acquired as the post-drive pressure Pb (first post-drive pressure) (S14). Thereafter, it is determined whether or not the change in the post-drive pressure Pb with respect to the pre-drive pressure Pa is greater than a predetermined threshold Th, that is, whether Pa−Pb> Th (S15).

  If an affirmative determination is made in S15, this process ends. If a negative determination is made in S15, it is determined whether or not the battery voltage VB is greater than a predetermined threshold value Vth (S16). When VB ≦ Vth, switching to liquid fuel injection is performed (S17). That is, when the battery voltage VB is low, fuel injection using liquid fuel instead of gas fuel is performed, thereby avoiding the inconvenience associated with the valve opening assist drive being performed with the battery voltage VB being low. The engine startability can be improved.

  If VB> Vth, valve opening assist driving is performed (S18). In the valve opening assist drive, a second drive signal is generated and output regardless of the required injection amount. As the second drive signal, a signal for continuously driving the gas injection valve 21, a signal for intermittently driving the gas injection valve 21, and the like are output. In S18, the period during which the second drive signal is output may be set according to the battery voltage VB. That is, when the battery voltage VB is relatively low, the output period of the second drive signal is set to be relatively short, and when the battery voltage VB is relatively high, the output period of the second drive signal is compared. Set it longer. In this case, driving of the gas injection valve 21 can be assisted while avoiding the battery voltage VB falling below the threshold value Vth.

  On the other hand, if a negative determination is made in S13, it is determined whether or not valve opening assist driving is being performed (S19). If a negative determination is made in S19, the process ends. When an affirmative determination is made in S19, the pressure Pc on the upstream side of the gas injection valve 21 during the valve opening assist drive, that is, during the output of the second drive signal is acquired (S20). Then, whether or not the change in pressure with the pressure Pc during the valve opening assist driving (pressure after the second driving) with respect to the pressure Pb before the valve opening assist driving (the pressure before the second driving) is greater than a predetermined threshold Th. It is determined whether or not Pb-Pc> Th (S21).

  If it is determined in S21 that the pressure change is larger than the threshold Th, the valve opening assist drive is terminated (S22). In addition to this, in S22, based on various parameters indicating the operating state of the engine 10, such as when the rotational speed of the engine 10 increases to a predetermined level or higher, or when the degree of increase in the rotational speed of the engine 10 increases to a predetermined level or higher. Thus, the valve opening assist drive may be terminated when it is determined that the gas injection valve 21 is in the valve open state.

  If a negative determination is made in S21, that is, if Pb−Pc ≦ Th, it is determined whether or not the valve opening assist drive is to be ended (S23). For example, when the driving time of the second driving signal reaches a predetermined time set in advance, when the output timing of the first driving signal of the gas injection valve 21 comes in the cylinder where fuel injection is performed next, the battery voltage VB Is determined to end the valve opening assist drive, for example, when the valve opening assist drive is less than the threshold value Vth.

  If the determination in S23 is affirmative, the valve opening assist drive is terminated (S22). If a negative determination is made in S23, this process is terminated. In this case, the valve opening assist drive being performed is continued.

  Next, an example of execution of the above process by the control unit 40 will be described with reference to FIG. In FIG. 3, only the state of the first cylinder (# 1) and the second cylinder (# 2) is shown for simplification of description. In FIG. 3, it is assumed that a valve opening abnormality has occurred in the first cylinder and that the second cylinder is normal (no valve opening abnormality has occurred).

  In the state where the starter is switched on at time t1, the pressure pre-drive pressure Pa1 is detected by the pressure sensor 38 of the first cylinder at the time t2 when the pressure before the first cylinder is injected is detected. A drive signal is output. Then, after the output of the first drive signal, a predetermined mask period elapses, and the post-drive pressure Pb1 is detected when the time of pressure after gas injection of the first cylinder comes at time t3. At this time, since ΔP1 (Pa1−Pb1) <Th and VB> Vth, the second drive signal is output by the valve opening assist drive. FIG. 3 shows an example of both the case where the gas injection valve 21 is continuously driven by the second drive signal and the case where the gas injection valve 21 is intermittently driven. Then, the pressure Pc during the valve opening assist drive (while the second drive signal is being output) is repeatedly detected.

  Then, after time t3, the output of the second drive signal is continued in a period where ΔP1 ≦ Th. Thereafter, when the gas injection valve 21 is opened, ΔP1> Th at time t4, the output of the second drive signal is stopped, and the valve opening assist drive is ended.

  At time t5, when the pre-injection timing of the gas injection valve 21 in the second cylinder is reached, the pre-drive pressure Pa2 is detected by the pressure sensor 38 of the second cylinder. The post-drive pressure Pb2 is detected at time t6 after the predetermined mask period has elapsed. At this time, ΔP2 (Pa2−Pb2)> Th is satisfied, the second drive signal is not output, and the gas injection valve 21 of the second cylinder is closed until the next fuel injection timing.

  According to the above, the following excellent effects are exhibited.

  In the engine 10 that uses gas fuel, there is a valve opening abnormality in which the gas injection valve 21 does not open at the gas fuel injection timing due to, for example, freezing of moisture contained in the gas fuel when it is in a low temperature state. May occur. Moreover, there is a possibility that the valve opening abnormality may occur even if foreign matters such as oil components adhere to the gas injection valve 21. Therefore, the pressure change before and after outputting the first drive signal generated based on the required injection amount is acquired, and if the pressure change is less than a predetermined threshold, it is determined that the gas injection valve 21 has a valve opening abnormality and the required injection amount. Regardless of the case, the generated second drive signal is output. In this case, the abnormality determination is performed using the gas pressure change directly related to the driving of the gas injection valve 21, and therefore the valve opening abnormality can be accurately determined. In addition, when the gas injection valve 21 has a valve opening abnormality, it is possible to appropriately perform a process for prompting the cancellation.

  -The output of the second drive signal is stopped when the pressure change before and after the output of the second drive signal exceeds a predetermined threshold. In this case, it is possible to promote the elimination of the valve opening abnormality of the gas injection valve 21 while minimizing the decrease in fuel consumption.

  When the valve opening abnormality of the gas injection valve 21 is resolved, the rotational speed of the engine 10 increases with the start of fuel injection. Therefore, the output of the second drive signal is stopped when the rotational speed of the engine 10 increases above a predetermined value or when the degree of increase in the rotational speed is greater than a predetermined value. In this case, the output of the second drive signal can be stopped according to the state of the engine 10.

  -When it is determined that the valve opening abnormality has occurred in the gas injection valve 21 of the first cylinder, before the injection timing of the gas injection valve 21 of the second cylinder that injects gas fuel next, The output of the second drive signal to the gas injection valve 21 of one cylinder is stopped. In this case, it is possible to promote the elimination of the valve opening abnormality of the gas injection valve 21 of the first cylinder while suppressing the influence on the detection of the valve opening abnormality of the gas injection valve 21 of the second cylinder.

  In the case where the valve opening abnormality has occurred in the gas injection valve 21, if the valve opening abnormality is not eliminated even if the second drive signal is output to the gas injection valve 21, the cylinder in which the gas injection valve 21 performs fuel injection On the other hand, liquid fuel was supplied instead of gas fuel. In this case, when the valve opening abnormality of the gas injection valve 21 is difficult to be solved, the startability of the internal combustion engine can be ensured.

  The second drive signal is output according to the power supply voltage of the battery 50. In this case, in consideration of the power supply voltage of the battery 50, it is possible to prompt the elimination of the valve opening abnormality of the gas injection valve 21.

  Since the valve opening abnormality of the gas injection valve 21 is calculated for each gas injection valve 21 (cylinder), the gas injection valve 21 (cylinder) in which the valve opening abnormality has occurred can be specified.

  The valve opening assist control can be performed only for the gas injection valve 21 that needs the valve opening assist control.

(Other embodiments)
The present invention is not limited to the description of the above embodiment, and may be implemented as follows. In the following description, the same components as those described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the processing of FIG. 2 described above, if the valve opening abnormality of the gas injection valve 21 is not solved even after the valve opening assist drive for the gas injection valve 21 of the same cylinder is repeatedly performed a predetermined number of times, a liquid is used instead of the gas fuel. Fuel injection with fuel may be performed. For example, when an affirmative determination is made in S16, it is determined whether or not the number of valve opening assist driving operations is less than a predetermined number. If an affirmative determination is made in S16, a second drive signal is output to the gas injection valve 21 as a valve opening assist drive in S17. When a negative determination is made in S16, liquid fuel is injected from the liquid injection valve 74 instead of gas fuel.

  In the above, the example in which the present invention is applied to the bi-fuel type engine 10 that uses gas fuel and liquid fuel as combustion fuel has been shown. However, the present invention uses only gas fuel as combustion fuel. The present invention can also be applied to the type of engine 10.

  In the above, the second injection signal may be output for a predetermined period.

  DESCRIPTION OF SYMBOLS 10 ... Engine, 21 ... Gas injection valve, 38 ... Pressure sensor, 40 ... Control part.

Claims (8)

A gas injection valve (21) for injecting gaseous fuel in the internal combustion engine (10);
Pressure detection means (38) for detecting the pressure of the gas fuel in the supply path of the gas fuel to the gas injection valve, and applied to a fuel injection system,
Fuel injection control means for generating a first drive signal of the gas injection valve according to a required injection amount calculated according to an operating state of the internal combustion engine, and for performing fuel injection by output of the first drive signal;
The difference between the first pre-drive pressure, which is a pressure detection value before the output of the first drive signal, and the first post-drive pressure, which is a pressure detection value after the output of the first drive signal, is less than a predetermined threshold. In this case, a second drive signal generating means for outputting a second drive signal generated regardless of the required injection amount to the gas injection valve, assuming that a valve opening abnormality that does not open the gas injection valve has occurred,
A fuel injection control device for an internal combustion engine, comprising:   2. The fuel injection control device for an internal combustion engine according to claim 1, wherein the second drive signal generation unit outputs the second drive signal for continuously driving the gas injection valve.   2. The fuel injection control device for an internal combustion engine according to claim 1, wherein the second drive signal generation unit outputs the second drive signal for intermittently driving the gas injection valve.   In the second drive signal generation means, the difference between the second pre-drive pressure before the output of the second drive signal and the second post-drive pressure after the output of the second drive signal is equal to or greater than a predetermined threshold. The fuel injection control device for an internal combustion engine according to claim 3, wherein the output of the second drive signal is stopped.   The second drive signal generation means is configured to increase the rotational speed of the internal combustion engine more than a predetermined value after the second drive signal is output, or to increase the rotational speed of the internal combustion engine greater than a predetermined value. 5. The fuel injection control device for an internal combustion engine according to claim 3, wherein the output of the second drive signal is stopped. The internal combustion engine includes, as the gas injection valve, a first gas injection valve that supplies gas fuel to the first cylinder, and a second gas injection valve that supplies gas fuel to a second cylinder different from the first cylinder. And
When it is determined that a valve opening abnormality has occurred in the first gas injection valve, the second drive signal generation means sends the first drive signal to the second gas injection valve that injects gas fuel next. The fuel injection control device for an internal combustion engine according to any one of claims 1 to 5, wherein output of the second drive signal to the first gas injection valve is stopped before the output. A liquid injection valve (22) for injecting liquid fuel;
If it is determined that the gas injection valve has a valve opening abnormality, if the valve opening abnormality is not resolved even if the second drive signal is output to the gas injection valve, the gas fuel is replaced with the gas fuel. The fuel injection control device for an internal combustion engine according to any one of claims 1 to 6, wherein the liquid fuel is supplied to a cylinder (20) of the internal combustion engine. The gas injection valve is driven by electric power from a power supply unit (50),
The fuel injection control device for an internal combustion engine according to any one of claims 1 to 7, wherein the drive signal generating means outputs the second drive signal in accordance with a power supply voltage of the power supply unit.

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