WO2014091680A1

WO2014091680A1 - Fuel injection control device for internal combustion engine, and vehicle fuel injection system

Info

Publication number: WO2014091680A1
Application number: PCT/JP2013/006772
Authority: WO
Inventors: 優一竹村; 溝渕　剛史; 和田　実; 和賢野々山; 福田　圭佑
Original assignee: 株式会社デンソー
Priority date: 2012-12-12
Filing date: 2013-11-19
Publication date: 2014-06-19
Also published as: JP2014114792A

Abstract

A pressure-regulating valve (60), which reduces the pressure of a fuel gas supplied to first injection valves (21), and a main tank stop valve (44) and a cutoff valve (45) are disposed in a fuel passage comprising a gas line (41). A control unit (80) determines whether a time point precedes a stoppage in fuel injection by the first injection valves (21), and determines whether a regulator upstream pressure is greater than or equal to a prescribed value that has been determined in advance. Furthermore, if the control unit (80) determines that the time point precedes a stoppage in fuel injection, and determines that the regulator upstream pressure is greater than or equal to the prescribed value, the control unit (80) reduces the regulator upstream pressure by opening the cutoff valve (45) and closing the main tank stop valve (44), while fuel continues to be injected by the first injection valves (21).

Description

Fuel injection control device for internal combustion engine and fuel injection system for vehicle

Cross-reference of related applications

This disclosure is based on Japanese Patent Application No. 2012-271377 filed on December 12, 2012, the contents of which are incorporated herein.

The present disclosure relates to an internal combustion engine fuel injection control device and a vehicle fuel injection system.

There is known an internal combustion engine in which gas fuel such as compressed natural gas (CNG) is burned. In such an internal combustion engine, a fuel supply system configured to supply gas fuel to the fuel 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 fuel injection valve. A pressure adjustment valve that adjusts the pressure of the gas fuel supplied from the pressure regulator, and a shut-off valve that is provided upstream of the pressure adjustment valve (that is, on the gas tank side) and blocks the flow of the gas fuel to the pressure adjustment valve Is known (see, for example, Patent Document 1).

JP-A-11-294222

In the pressure regulating valve, it is considered that fuel leakage occurs in the valve body seat portion. In particular, the higher the fuel pressure in the high pressure passage portion between the gas tank and the pressure regulating valve, the more likely the fuel leakage occurs. When fuel injection without consuming gas fuel is stopped, fuel injection at the pressure regulating valve causes an excessive increase in injection pressure (supply gas pressure), which may affect the valve opening operation of the valve body in the gas fuel injection valve. Concerned. In this case, there is a possibility that the valve body cannot move to the valve opening position due to excessive increase in the injection pressure, and the gas fuel cannot be normally injected.

The present disclosure suppresses the inconvenience that the injection pressure excessively increases due to fuel leakage at the pressure control valve while the gas fuel injection is stopped, and that the gas fuel injection is hindered after resumption of the gas fuel injection. The main object of the present invention is to provide a fuel injection control device for an internal combustion engine and a fuel injection system for a vehicle.

The present disclosure includes a gas tank that stores gas fuel in a high-pressure state, a gas fuel injection valve that injects gas fuel supplied from the gas tank through a fuel passage, and the fuel passage that is provided to the gas fuel injection valve. A pressure regulating valve that depressurizes and adjusts the pressure of the gas fuel, and a shut-off valve that is provided on the upstream side of the pressure regulating valve in the fuel passage and in the vicinity thereof, and has a shut-off function that shuts off the flow of the gas fuel; The present invention is applied to a fuel injection system provided with a tank outlet valve provided in the vicinity of a fuel outlet of the gas tank and having a shut-off function for shutting off the flow of gas fuel. The fuel pressure in the high-pressure passage between the gas tank and the pressure regulating valve is determined in advance, and the injection stop determining means for determining that the fuel injection by the gas fuel injection valve is before stopping A pressure determination means for determining whether or not the fuel pressure is equal to or greater than a predetermined value; and the injection stop determination means determines that the time is before the injection stop, and the pressure determination means determines that the fuel pressure in the high-pressure passage is a predetermined value. When it is determined that the fuel pressure of the high-pressure passage portion is maintained, the shutoff valve is opened and the tank outlet valve is closed or open restricted while fuel injection by the gas fuel injection valve is continued. Pressure control means for reducing the pressure.

In the fuel supply system for gas fuel, high-pressure gas fuel that has flowed out of the gas tank is depressurized and adjusted by the pressure adjustment valve, and then supplied to the gas fuel injection valve. In this case, under the situation where the upstream side of the pressure regulating valve is at a high pressure in the fuel passage, the high pressure fuel is likely to leak from the upstream side to the downstream side in the pressure regulating valve, and the injection pressure ( It is conceivable that an excessive increase in the pressure of the gas fuel supplied to the gas fuel injection valve occurs. If such an excessive increase in the injection pressure occurs, there is a concern that the valve opening operation of the valve body will be affected in the gas fuel injection valve. As a result, the valve body cannot move to the valve opening position due to the excessive increase in the injection pressure, and the gas is not gas. It may not be possible to inject fuel normally.

In the above configuration, if the fuel pressure in the high pressure passage between the gas tank and the pressure regulating valve is in a high pressure state before the fuel injection by the gas fuel injection valve is stopped, the fuel by the gas fuel injection valve With the injection continued, the shutoff valve is opened, the tank outlet valve is closed or the opening is restricted, and the fuel pressure in the high pressure passage is lowered. In this case, the fuel pressure in the high-pressure passage is actively lowered before the gas fuel injection is stopped, so that the fuel leakage at the pressure regulating valve is less likely to occur, and even if the fuel leakage occurs, the injection pressure is reduced. The rise level can be suppressed. As a result, it is possible to suppress the inconvenience that the injection pressure is excessively increased due to fuel leakage at the pressure control valve while the injection of the gas fuel is stopped, and that the injection of the gas fuel is hindered after the injection of the gas fuel is resumed.

FIG. 1 is a configuration diagram showing an outline of an engine fuel injection system. FIG. 2 is a diagram showing a schematic configuration of the first injection valve. FIG. 3 is a diagram illustrating a schematic configuration of a regulator. FIG. 4 is a schematic diagram showing the arrangement of components of the fuel injection system in the vehicle. FIG. 5 is a flowchart showing a first fuel injection control process. FIG. 6 is a flowchart showing a second fuel injection control process. FIG. 7 is a flowchart showing a third fuel injection control process. FIG. 8 is a time chart for specifically explaining the fuel injection control. FIG. 9 is a time chart for specifically explaining the fuel injection control. FIG. 10 is a flowchart showing a regulator upstream pressure control process. FIG. 11 is a time chart for specifically explaining regulator upstream pressure control processing. FIG. 12 is a flowchart showing a first fuel injection control process in another embodiment.

Hereinafter, an embodiment of the present disclosure 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 embodied as a fuel injection system. An overall schematic diagram of this system is shown in FIG.

1 is an inline three-cylinder spark ignition 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 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 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, a first injection valve 21 for injecting gas fuel (CNG fuel), and a second injection valve 22 for injecting liquid fuel (gasoline). And have. Each of these

injection valves

21 and 22 injects fuel into the branch pipe portion 13a of the intake manifold 13 in the intake system 11, and gas fuel is supplied to the intake port of each cylinder by the injection of the first injection valve 21. The liquid fuel is supplied to the intake port of each cylinder by the injection of the second injection valve 22.

Each of the

injection valves

21 and 22 is an open / close type control valve in which the valve body is lifted from the closed position to the open position by electrically driving the electromagnetic drive unit. Each valve is driven to open by a valve opening drive signal. These

injection valves

21 and 22 are opened by energization and closed by energization interruption. An amount of fuel (gas fuel, liquid fuel) corresponding to the energization time is injected from each of the

injection valves

21 and 22. In the present embodiment, the injection pipe 23 is connected to the tip of the first injection valve 21, and the gas fuel injected from the first injection valve 21 passes through the injection pipe 23 to the branch pipe portion 13 a of the intake manifold 13. It comes to be injected.

Here, the configuration of the first injection valve 21 for gas injection will be described with reference to FIG. 2A shows a non-injection state, and FIG. 2B shows an injection state. The first injection valve 21 has a self-sealing structure in which the closing sealing performance is enhanced by the pressure of the gas fuel supplied to itself.

A valve body 32 is slidably accommodated in the cylindrical body 31, and the valve body 32 is biased in the valve closing direction by a spring 33 in the body 31. In FIG. 2A, the nozzle hole 34 provided at the tip of the injection valve is closed by the tip of the valve body 32. In the body 31, a first fuel chamber 35 is provided on the rear end side (upstream side) of the valve body 32, and a second fuel chamber 36 is provided on the front end side (downstream side) of the valve body 32. Yes. The valve body 32 is provided with a small-diameter portion 32a on the tip side of the sliding portion, and a second fuel chamber 36 is provided around the small-diameter portion 32a. The first fuel chamber 35 and the second fuel chamber 36 are in communication with each other via a fuel passage 37 provided in the valve body 32. The inlet side of the fuel passage 37 communicates with the first fuel chamber 35, and the outlet side thereof It leads to the second fuel chamber 36. The valve body 32 is displaced to the valve opening position in response to energization to the electromagnetic drive unit 38 composed of a solenoid or the like.

In the first injection valve 21 configured as described above, gas fuel is supplied from a regulator 43 described later to the first fuel chamber 35, and the gas fuel is also introduced into the second fuel chamber 36 through the fuel passage 37. As shown in FIG. 2B, when the valve body 32 is displaced to the valve opening position against the biasing force of the spring 33 as the electromagnetic drive unit 38 is energized, the nozzle hole 34 is opened, and the gas is discharged. Fuel is injected.

In the first injection valve 21, the valve body 32 is provided with a small-diameter portion 32 a on the distal end side thereof, so that the pressure receiving area on the first fuel chamber 35 side and the pressure receiving side on the second fuel chamber 36 side in the valve-closed state. The area is “pressure receiving area on the first fuel chamber 35 side> pressure receiving area on the second fuel chamber 36 side” (see FIG. 2A). Therefore, in the valve closing state shown in FIG. 2A, the pressure of the gas fuel supplied from the regulator 43 side (corresponding to the injection pressure) is in the direction in which the valve body 32 is closed (valve closing direction). It comes to act more greatly. 2B, the injection pressure also acts on the end face (the lower end face in the figure) of the small-diameter portion 32a, so that the fuel pressure in the valve closing direction acting on the valve body 32 and the valve opening direction are also applied. The fuel pressure is almost the same.

Next, returning to the description of FIG. 1, the configuration of the gas fuel supply unit 40 that supplies the gas fuel to the first injection valve 21 and the liquid fuel supply unit 70 that supplies the liquid fuel to the second injection valve 22. Will be described.

In the gas fuel supply unit 40, a gas tank 42 is connected to the first injection valve 21 via a gas pipe 41, and the pressure of the gas fuel supplied to the first injection valve 21 is in the middle of the gas pipe 41. There is provided a regulator 43 having a pressure adjusting function for adjusting the pressure under pressure. The regulator 43 (a pressure adjusting valve 60, which will be described in more detail later) is configured to use gas fuel in a high pressure state (for example, a maximum of 20 MPa) stored in the gas tank 42 with a predetermined set pressure (for example, an injection pressure of the first injection valve 21) The gas fuel after the pressure reduction adjustment is supplied to the first injection valve 21 through the gas pipe 41. In the gas pipe 41, the upstream side of the regulator 43 is a high-pressure pipe portion 41a that forms a high-pressure side passage, and the downstream side is a low-pressure pipe portion 41b that forms a low-pressure side passage.

Further, a gas fuel passage formed by the gas pipe 41 and the like further includes a tank main stop valve 44 (tank outlet valve) disposed in the vicinity of the fuel outlet of the gas tank 42 and a downstream side of the tank main stop valve 44. And a shutoff valve 45 disposed in the vicinity of the fuel inlet of the regulator 43. The

valves

44, 45 allow and shut off the flow of gas fuel in the gas pipe 41. Yes. Both the tank main stop valve 44 and the shut-off valve 45 are electromagnetic on-off valves, and are normally closed so that the flow of gas fuel is cut off when not energized and the flow of gas fuel is allowed when energized.

In the gas piping 41, a pressure sensor 46 for detecting the fuel pressure and a temperature sensor 47 for detecting the fuel temperature are provided in the high pressure piping portion 41a, and a pressure sensor 48 for detecting the fuel pressure in the low pressure piping portion 41b. A temperature sensor 49 for detecting the fuel temperature is provided. The gas tank 42 is provided with a tank internal pressure sensor 50 that detects a tank internal pressure that is an internal pressure of the gas tank 42.

The shut-off valve 45 and the pressure sensor 46 can be provided integrally with the regulator 43. In this embodiment, a configuration in which the shut-off valve 45 and the pressure sensor 46 are provided integrally with the regulator 43 is adopted. .

A specific configuration of the regulator 43 will be described with reference to FIG. The regulator 43 constitutes a mechanical pressure adjusting device that adjusts the fuel pressure in the low-pressure pipe portion 41b with respect to a mechanically determined set pressure.

In FIG. 3, the regulator 43 has a high-pressure passage 51 connected to the high-pressure piping portion 41a and a low-pressure passage 52 connected to the low-pressure piping portion 41b. The high-pressure passage 51 includes a shut-off valve 45 and a pressure sensor. 46 is provided. The pressure sensor 46 detects the pressure of the gas fuel upstream of the shutoff valve 45. Reference numeral 53 is a filter for removing foreign matter.

The configuration of the shut-off valve 45 is substantially the same as the configuration of the first injection valve 21 and has a self-sealing structure. The configuration will be briefly described. The shut-off valve 45 has a valve body 55 biased in the valve closing direction by a spring 54, and the valve body 55 is closed against the biasing force of the spring 54 by energizing the electromagnetic drive unit 56. The valve is displaced from the position to the valve opening position. A first fuel chamber 57 is provided on the rear end side (upstream side) of the valve body 55, and a second fuel chamber 58 is provided on the distal end side (downstream side where the small diameter portion is provided) of the valve body 55. Yes. Both the

fuel chambers

57 and 58 are communicated with each other through a fuel passage 59 provided in the valve body 55. In this case, high-pressure gas fuel is supplied to both the

fuel chambers

57 and 58 from the gas tank 42, and in the closed state of the shutoff valve 45, a closing force is applied to the valve body 55 by the fuel pressure on the gas tank 42 side. . When the valve element 55 is displaced to the valve open position against the biasing force of the spring 54 with the energization of the electromagnetic drive unit 56 (as shown), high-pressure gas fuel flows downstream.

In the regulator 43, a pressure regulating valve 60 is provided on the downstream side of the shutoff valve 45. As a configuration of the pressure regulating valve 60, a valve body chamber 61 is provided in the high pressure passage 51, and a valve body 62 is accommodated in the valve body chamber 61. The valve body 62 is an opening / closing member that opens and closes the valve seat portion 63 that is an inlet portion of the low pressure passage 52. If the valve body 62 is in the open position, the valve seat portion 63 is opened and the high pressure passage 51, the low pressure passage 52, Is communicated. If the valve body 62 is in the closed position, the valve seat 63 is closed and the communication between the high pressure passage 51 and the low pressure passage 52 is blocked.

The valve body 62 is opened and closed according to the fuel pressure (corresponding to the injection pressure) in the low-pressure passage 52 and the force in the valve opening direction generated by the valve body operating portion 65. The valve element actuating portion 65 is a space that is open to the atmosphere, and has an air opening portion 67 in which an adjustment spring 66 is provided, and a diaphragm as a partition member that partitions the air release portion 67 and the low-pressure passage 52. 68. The diaphragm 68 is provided integrally with the valve body 62. Fuel pressure in the low pressure passage 52 acts on the diaphragm 68 as a force in the valve closing direction, and an urging force of the adjustment spring 66 and atmospheric pressure act as a force in the valve opening direction.

In such a configuration, if “force in the valve closing direction> force in the valve opening direction” is satisfied, the valve body 62 is held in the valve closing position. On the other hand, when the fuel pressure in the low pressure passage 52 decreases due to fuel injection or the like of the first injection valve 21 and becomes “force in the valve closing direction <force in the valve opening direction”, the valve element 62 opens with the displacement of the diaphragm 68. To be spoken. At this time, the opening position (valve lift amount) of the valve body 62 is determined according to the difference between the force in the valve closing direction and the force in the valve opening direction, and the opening area of the valve seat 63 is changed according to the opening position. As a result, the amount of fuel flowing from the high pressure passage 51 into the low pressure passage 52 is adjusted.

A relief valve 69 that vents gas when the fuel pressure in the low pressure passage 52 becomes abnormally high is provided in the branch portion 52a branched from the low pressure passage 52.

In the present embodiment, in the regulator 43, the pressure adjusting means is constituted by the pressure adjusting valve 60 made up of components such as the valve body 62 and the valve body operating portion 65. In the configuration of FIG. 3, the shut-off valve 45, the pressure sensor 46, and the pressure adjustment valve 60 are integrally provided in the regulator 43. However, the shut-off valve 45 and the pressure sensor 46 are separated from the regulator 43 in the high-pressure piping 41 a. It is also possible to provide it.

1, in the liquid fuel supply unit 70, a fuel tank 72 is connected to the second injection valve 22 via a fuel pipe 71. The fuel pipe 71 is provided with a fuel pump 73 that feeds the liquid fuel in the fuel tank 72 to the second injection valve 22.

The control unit 80 includes a CPU 81, a ROM 82, a RAM 83, a backup RAM 84, an interface 85, and a bidirectional bus 86. The CPU 81, ROM 82, RAM 83, backup RAM 84, and interface 85 are connected to each other by a bidirectional bus 86.

The CPU 81 executes a routine (program) for controlling the operation of each unit in the system. The ROM 82 stores in advance various data such as a routine executed by the CPU 81, maps (including tables, relational expressions, and the like), parameters, and the like referred to when the routine is executed. The RAM 83 temporarily stores data as necessary when the CPU 81 executes a routine. The backup RAM 84 appropriately stores data under the control of the CPU 81 in a state where the power is turned on, and retains the stored data even after the power is shut off.

The interface 85 includes sensors (crank angle sensor, air flow meter, air flow meter, etc.) provided in the present system, including the throttle opening sensor 15b, the exhaust sensor 18, the

pressure sensors

46, 48, the

temperature sensors

47, 49, and the tank internal pressure sensor 50 described above. A cooling water temperature sensor, a vehicle speed sensor, etc.) are electrically connected, and outputs (detection signals) from these sensors are transmitted to the CPU 81. The interface 85 is electrically connected to driving units such as the throttle actuator 15a, the ignition device 20a, the

injection valves

21 and 22, the tank main stop valve 44, the shutoff valve 45, and the like, and drives these driving units. Therefore, the drive signal sent from the CPU 81 is output toward the drive unit. That is, the control unit 80 acquires an operation state based on the output signals of the above-described sensors, and performs the above-described drive unit control based on the operation state.

FIG. 4 is a schematic diagram showing the arrangement of components of the fuel injection system in the vehicle “C”. As shown in FIG. 4, the vehicle “C” has an engine 10 disposed in the front portion of the vehicle, and a regulator 43 and a shut-off valve 45 are provided in the vicinity of the engine. The engine 10 is provided with a first injection valve 21. On the other hand, a gas tank 42 is disposed at the rear of the vehicle, and a tank main stop valve 44 is provided at the outlet thereof. And the gas piping 41 is provided so that it may extend in the vehicle front-back direction.

By the way, under the situation where the regulator upstream pressure (upstream pressure of the pressure regulating valve 60) is high, the pressure regulating valve 60 is likely to leak high pressure fuel from the upstream side to the downstream side. Therefore, it is considered that the injection pressure is excessively increased. When such an excessive increase in the injection pressure occurs, there is a concern that the valve opening operation of the valve body 32 may be affected in the first injection valve 21, and as a result, the valve body 32 moves to the valve opening position due to the excessive increase in the injection pressure. There is a risk that the gas fuel cannot be injected normally. Specifically, the first injection valve 21 has a self-sealing structure as described above, and the fuel pressure (injection pressure) on the downstream side of the regulator acts in the direction in which the valve body 32 is closed. Therefore, the higher the injection pressure, the harder it is to open the valve.

Therefore, in the present embodiment, the control unit 80 determines that it is a time before the fuel injection by the first injection valve 21 is stopped, and determines whether the regulator upstream pressure is equal to or higher than a predetermined value. When it is determined that it is a time before the stop of the injection and the regulator upstream pressure is equal to or higher than a predetermined value, the shutoff valve 45 is opened while the fuel injection by the first injection valve 21 is continued. The main stop valve 44 is closed to reduce the regulator upstream pressure (injection stop determination means, pressure determination means, pressure control means).

Further, in this embodiment, it is determined that the fuel injection is stopped before the fuel injection is stopped by the first injection valve 21 (in other words, the fuel injection is likely to be stopped). The following (1) to (3) are assumed as means for performing this.
(1) Based on the request for switching from gas fuel to liquid fuel, it is determined that the time is before the stop of injection of gas fuel.
(2) Based on the determination that the vehicle is in a predetermined low load state, it is determined that the time is before the stop of the injection of gas fuel.
(3) Based on the request for stopping the engine, it is determined that the time is before the stop of gas fuel injection. In addition, if the engine stop request | requirement has arisen during the injection of gas fuel, it is equivalent to the injection stop request | requirement of gas fuel having arisen.

Hereinafter, the fuel injection control process in each of the cases (1) to (3) will be described with reference to the flowcharts of FIGS. FIG. 5 is a flowchart showing the fuel injection control process in the case (1), FIG. 6 is a flowchart showing the fuel injection control process in the case (2), and FIG. 7 is the above (3). 6 is a flowchart showing a fuel injection control process in the case of FIG. Each of these processes is repeatedly performed by the CPU 81 of the control unit 80 at a predetermined cycle. The process of FIG. 5 is called a first fuel injection control process, the process of FIG. 6 is called a second fuel injection control process, and the process of FIG. 7 is called a third fuel injection control process.

In the first fuel injection control process shown in FIG. 5, in step S11, it is determined whether or not it is a time point before the stop of the injection of the gas fuel depending on whether or not a request for switching from the gas fuel to the liquid fuel is generated. . At this time, the switching from the gas fuel to the liquid fuel may be performed based on, for example, the engine operating state or the remaining amount of fuel. If no switching request is generated, the process is terminated.

If a switching request is generated, the process proceeds to step S12, and a close command for closing the tank main stop valve 44 is output. Thereafter, in step S13, it is determined whether or not the regulator upstream pressure is equal to or higher than a predetermined determination value K1. The regulator upstream pressure is calculated from the detection value of the pressure sensor 46. Alternatively, the regulator upstream pressure may be calculated from the detection value of the tank internal pressure sensor 50. Since the determination in step S13 is made immediately after the main tank stop valve 44 is closed (or when the tank is closed) when step S11 becomes YES, the regulator upstream pressure is calculated from the detected value of the tank internal pressure sensor 50. Is possible. The determination value K1 is a threshold value for determining whether the regulator upstream pressure is high enough to affect the valve opening operation of the shutoff valve 45, and is, for example, 10 MPa.

If the regulator upstream pressure is less than the determination value K1, the process proceeds to step S14, and a close command for closing the shutoff valve 45 is output. In the subsequent step S15, the injection of gas fuel by the first injection valve 21 is stopped. Thereafter, this process is terminated.

Further, if the regulator upstream pressure is equal to or higher than the judgment value K1, the shutoff valve 45 is not immediately closed and the switching to the liquid fuel is not performed, and the following steps S16 to S18 are performed.

That is, in step S16, the update of the air-fuel ratio learning value in the air-fuel ratio feedback control is prohibited. Air-fuel ratio feedback control and air-fuel ratio learning will be briefly described. The controller 80 calculates a deviation between the actual air-fuel ratio detected by the exhaust sensor 18 and a target air-fuel ratio (for example, the theoretical air-fuel ratio), and calculates an air-fuel ratio feedback correction value based on the deviation. Then, the injection amount of the gas fuel is corrected by the air-fuel ratio feedback correction value. Further, an air-fuel ratio learning value is calculated based on the air-fuel ratio feedback correction value, and the learned value is stored in the backup RAM 84 (or EEPROM). At this time, the previous value of the air-fuel ratio learning value is updated with the current value. In step S16, such update of the air-fuel ratio learning value is prohibited.

In step S17, abnormality determination of the gas fuel supply system is prohibited. The abnormality determination of the gas fuel supply system will be briefly described. The control unit 80 determines abnormality of the gas piping 41 (high pressure piping portion 41a) according to the regulator upstream pressure during the injection of gas fuel. However, in this case, under the situation where gas fuel is being injected, depending on whether the tank main stop valve 44 is open or closed, the magnitude of the fuel pressure in the gas pipe 41 and the behavior of the change may vary. Is different. Therefore, if the tank main stop valve 44 is closed while the gas fuel is being injected, there is a risk of erroneous determination. Further, in the gas fuel injection state, the magnitude of the injection pressure fluctuates according to the operating load of the engine 10, and the injection pressure becomes higher at low loads such as an idle with a relatively small fuel injection amount. The injection pressure becomes lower at a high load with a relatively large amount. In the control unit 80, a normal range of the injection pressure is determined for each load region, and abnormality determination of the pressure adjustment valve 60 is performed depending on whether or not the injection pressure is within the normal range. However, in this case, if the tank main stop valve 44 is closed while the gas fuel is being injected, there is a risk of erroneous determination. In step S17, such abnormality determination is prohibited. Alternatively, the abnormality determination may be limited by changing the abnormality determination value used in the abnormality determination.

In step S18, the estimation of the remaining amount of fuel in the gas tank 42 is prohibited. The fuel remaining amount estimation process will be briefly described. There is a correlation between the remaining amount of fuel in the gas tank 42 and the tank internal pressure. Therefore, the relationship between the fuel remaining amount in the gas tank 42 and the tank internal pressure is obtained in advance, and the control unit 80 calculates the tank internal pressure from the detection value of the tank internal pressure sensor 50 and estimates the fuel remaining amount based on the tank internal pressure. To do. Alternatively, since the tank internal pressure and the regulator upstream pressure are substantially the same in a state where the tank main stop valve 44 is opened, the control unit 80 calculates the tank internal pressure from the detection value of the pressure sensor 46 and based on the tank internal pressure. To estimate the remaining fuel. In step S18, such estimation of the remaining amount of fuel is prohibited.

In the second fuel injection control process shown in FIG. 6, in step S21, it is determined whether the regulator upstream pressure is equal to or higher than a predetermined determination value K1 (similar to step S13 in FIG. 5). In step S22, It is determined whether or not it is a time point before the stop of the injection of the gas fuel depending on whether or not the engine is idling. If the regulator upstream pressure is less than the determination value K1 or not during idling, the process proceeds to step S23, and an opening command for opening the tank main stop valve 44 is output. If the tank main stop valve 44 has already been opened, the opened state is maintained.

Further, if the regulator upstream pressure is equal to or higher than the determination value K1 and the engine is idling, the process proceeds to step S24, and a close command for closing the tank main stop valve 44 is output. Thereafter, in steps S25 to S27, processing for prohibiting update of the air-fuel ratio learning value in air-fuel ratio feedback control, processing for prohibiting determination of abnormality in the gas fuel supply system, and processing for prohibiting estimation of the remaining amount of fuel in the gas tank 42 are performed. Each is carried out (similar to steps S16 to S18 in FIG. 5).

In the third fuel injection control process shown in FIG. 7, in step S31, it is determined whether or not it is a time point before the stop of the injection of gas fuel, depending on whether or not a stop request for the engine 10 is generated. At this time, for example, when the ignition switch is turned off, it is determined that an engine stop request is generated. If no engine stop request is generated, the process proceeds to step S32, and an opening command for opening the tank main stop valve 44 is output. If the tank main stop valve 44 has already been opened, the opened state is maintained.

If an engine stop request is generated, the process proceeds to step S33, and a close command for closing the tank main stop valve 44 is output. Thereafter, in step S34, it is determined whether or not the regulator upstream pressure is equal to or higher than a predetermined determination value K1 (similar to step S13 in FIG. 5). If the regulator upstream pressure is less than the determination value K1, the process proceeds to step S35, and a close command for closing the shutoff valve 45 is output. In the subsequent step S36, the injection of gas fuel by the first injection valve 21 is stopped. Thereafter, this process is terminated.

If the regulator upstream pressure is equal to or higher than the determination value K1, in steps S37 to S39, processing for prohibiting update of the air-fuel ratio learning value in air-fuel ratio feedback control, processing for prohibiting abnormality determination of the gas fuel supply system, and gas tank 42 are performed. The process for prohibiting the estimation of the remaining amount of fuel is performed (similar to steps S16 to S18 in FIG. 5).

Thereafter, in step S40, the injection of gas fuel by the first injection valve 21 is continued. Thereafter, this process is terminated.

Next, the operation of the fuel injection control will be described more specifically. FIG. 8 is a time chart for explaining the operation when a request to switch from gas fuel to liquid fuel is generated, and this corresponds to the first fuel injection control process described in FIG. In FIG. 8, before the timing t1, the fuel is injected with the gas fuel, and both the tank main stop valve 44 and the shutoff valve 45 are in the open state.

Now, at timing t1, a request for switching from gas fuel to liquid fuel is generated. In this example, at the timing t1, the tank internal pressure and the regulator upstream pressure are the same pressure, and are both equal to or higher than the determination value K1. Then, at this timing t1, the tank main stop valve 44 is closed while the shut-off valve 45 and the gas fuel injection by the first injection valve 21 are continued. As a result, the regulator upstream pressure starts to decrease while the tank internal pressure is maintained at a high level.

Thereafter, at timing t2, the regulator upstream pressure decreases to the determination value K1, and the shutoff valve 45 is closed accordingly. In addition, the injection of gas fuel by the first injection valve 21 is stopped and the injection of liquid fuel by the second injection valve 22 is started. After timing t2, the regulator upstream pressure is held at a substantially constant value in the vicinity of the determination value K1. In this case, even if the pressure regulating valve 60 leaks to the low pressure side of the high pressure gas fuel via the valve body seat portion (valve seat portion 63), the injection pressure (supply gas pressure to the first injection valve 21). ) Can be prevented from occurring. Therefore, when restarting the subsequent injection of the gas fuel, it is possible to suppress the inconvenience that it becomes difficult to perform the fuel injection of the first injection valve 21 due to the injection pressure being too high.

FIG. 9 is a time chart for explaining the operation when the engine operating state becomes an idle state (low load state), and this corresponds to the second fuel injection control process described in FIG. . Note that immediately before the timing t11 at which the engine 10 is in the idle state, for example, the engine load factor is reduced as the accelerator depression amount is reduced. In FIG. 9, before the timing t11, the fuel injection by the gas fuel is being performed, and the tank main stop valve 44 and the shutoff valve 45 are both opened.

Now, at timing t11, an idle flag is set. In this example, at the timing t11, the tank internal pressure and the regulator upstream pressure are the same pressure, and are both equal to or higher than the determination value K1. At the timing t11, the tank main stop valve 44 is closed while the state in which the shutoff valve 45 is opened and the state in which the gas fuel is injected by the first injection valve 21 are continued. As a result, the regulator upstream pressure starts to decrease while the tank internal pressure is maintained at a high level.

After that, at timing t12, the regulator upstream pressure decreases to the determination value K1, and the tank main stop valve 44 is opened accordingly. As a result, the regulator upstream pressure rises, and when the regulator upstream pressure reaches the determination value K2 set by “K1 + α” at the timing t13, the tank main stop valve 44 is closed again. Then, the regulator upstream pressure decreases again. Note that the determination value K2 in the fuel injection control process of FIG. 6 described above means that hysteresis is provided in the determination process of step S21. After the tank main stop valve 44 is closed, the regulator upstream pressure decreases to K1, and after the tank main stop valve 44 is opened, the regulator upstream pressure reaches K2 on the higher pressure side than K1. Thus, the tank main stop valve 44 is closed again.

Thereafter, at timing t14, when an engine stop request is generated by turning off the ignition switch or the like, the shutoff valve 45 is closed and the gas fuel injection by the first injection valve 21 is stopped. After timing t14, the regulator upstream pressure is maintained at a pressure between the determination values K1 and K2. In this case, even if the pressure regulating valve 60 leaks to the low pressure side of the high pressure gas fuel via the valve body seat portion (valve seat portion 63), the injection pressure (supply gas pressure to the first injection valve 21). ) Can be prevented from occurring. Therefore, when the engine is restarted thereafter, it is possible to suppress the inconvenience that the fuel injection of the first injection valve 21 is difficult to be performed due to the injection pressure being too high and the engine start is adversely affected.

According to the embodiment described above in detail, the following excellent effects can be obtained.

If the upstream pressure of the regulator is in a predetermined high pressure state before the fuel injection is stopped in the engine operating state by the gas fuel injection of the first injection valve 21, the fuel injection by the first injection valve 21 is continued. The shut-off valve 45 is opened and the tank main stop valve 44 is closed to reduce the regulator upstream pressure. In this case, by positively lowering the regulator upstream pressure before stopping the injection of gas fuel, fuel leakage at the pressure regulating valve 60 is less likely to occur, and even if fuel leakage occurs, the injection pressure rise level Can be suppressed. As a result, it is possible to suppress the inconvenience that the injection pressure excessively rises due to fuel leakage at the pressure regulating valve 60 while the gas fuel injection is stopped, and that the gas fuel injection is hindered after the gas fuel injection is resumed. .

When a request for switching from an operation state using gas fuel to an operation state using liquid fuel is made, it is determined that the fuel injection by the first injection valve 21 is stopped, and the regulator as described above. A process for reducing the upstream pressure was performed. Similarly, when a gas fuel injection stop request is generated, it is determined that the time is before fuel injection by the first injection valve 21 is stopped, and the processing for reducing the regulator upstream pressure is performed as described above. I tried to do it. In this case, after the injection of gas fuel is stopped (after switching to liquid fuel and after the engine is stopped), the injection pressure rises excessively, and the injection of gas fuel is hindered when the injection with the gas fuel is resumed thereafter. Inconvenience can be suppressed.

When the engine 10 is in a low load state such as idle, it is conceivable that the engine 10 is subsequently stopped (a stop request is generated). Therefore, in the case of a low load state, the regulator upstream pressure is reduced in anticipation of the engine being stopped after that. As a result, it is possible to suppress the inconvenience that the injection pressure increases excessively after the engine is stopped and the gas fuel injection is hindered when the injection with the gas fuel is resumed thereafter.

The update of the air-fuel ratio learning value is prohibited when the shutoff valve 45 is opened and the tank main stop valve 44 is closed while the fuel injection by the first injection valve 21 is continued. When the gas fuel is injected with the tank main stop valve 44 closed, the upstream side of the regulator is higher than when the gas fuel is injected with the tank main stop valve 44 opened (normal time). The mode of change in pressure and injection pressure is different. Therefore, there is a concern that the correction value of the gas fuel injection amount becomes a value different from the normal value. In this respect, since the update of the learning value is prohibited when the gas fuel is injected with the tank main stop valve 44 closed, erroneous learning can be prevented. Therefore, it is possible to suppress the inconvenience that the emission is deteriorated due to erroneous learning.

When the shutoff valve 45 is in the open state and the tank main stop valve 44 is in the closed state while the fuel injection by the first injection valve 21 is continued, the abnormality determination in the fuel supply system of the gas fuel is stopped or limited. . When the gas fuel is injected with the tank main stop valve 44 closed, the upstream side of the regulator is higher than when the gas fuel is injected with the tank main stop valve 44 opened (normal time). The mode of change in pressure and injection pressure is different. Accordingly, there is a concern that the regulator upstream pressure and the injection pressure may be out of the normal range even though the configuration of the fuel supply system such as the shutoff valve 45 and the pressure regulating valve 60 is normal. In the present embodiment, the abnormality determination is stopped or limited when gas fuel is injected with the tank main stop valve 44 closed, so that erroneous determination of abnormality can be prevented.

The estimation of the remaining amount of fuel in the gas tank 42 is prohibited when the shutoff valve 45 is opened and the tank main stop valve 44 is closed while the fuel injection by the first injection valve 21 is continued. When gas fuel is injected with the tank main stop valve 44 closed, the regulator upstream pressure decreases regardless of the tank internal pressure. Therefore, when the remaining fuel amount in the gas tank 42 is estimated based on the upstream pressure of the regulator (the pressure detected by the pressure sensor 46), the remaining fuel amount may be erroneously estimated. Further, when the remaining amount of fuel in the gas tank 42 is estimated based on the detected value of the tank internal pressure (detected pressure of the tank internal pressure sensor 50), the amount of fuel actually consumed is not reflected, so that the remaining amount of fuel is also used. May be estimated incorrectly. In this embodiment, since estimation of the remaining amount of fuel is prohibited when gas fuel is injected with the tank main stop valve 44 closed, erroneous estimation of the remaining amount of fuel can be prevented.

As a vehicle fuel injection system, the engine 10, the first injection valve 21, the pressure regulating valve 60, and the shutoff valve 45 are mounted on the front portion of the vehicle, and the gas tank 42 and the tank main stop valve 44 are mounted on the rear portion of the vehicle. Adopted the configuration. The gas pipe 41 between the gas tank 42 and the pressure regulating valve 60 becomes longer, and the passage volume increases accordingly. Therefore, even if the tank main stop valve 44 is closed before the fuel injection by the first injection valve 21 is stopped, the fuel injection for a while after that is performed in the gas pipe 41 between the gas tank 42 and the pressure regulating valve 60. Therefore, it is convenient to continue the injection of the gas fuel while lowering the regulator upstream pressure as described above.

(Other embodiments)
You may change the said embodiment as follows, for example.

The tank main stop valve 44 may have a function capable of variably adjusting the opening degree. In this case, the control unit 80 controls the opening degree of the tank main stop valve 44, and thereby the regulator upstream pressure is controlled to be in a predetermined pressure range (for example, a pressure range equal to or lower than the determination value K2). Control for adjusting the opening of the tank main stop valve 44 to the closed side with respect to the fully open state corresponds to “control for bringing the tank main stop valve 44 into the open restriction state”. Specifically, as shown in FIG. 10, it is determined in step S41 whether or not the tank internal pressure is equal to or higher than a predetermined determination value K3. If NO, the process proceeds to step S42 and the tank main stop valve 44 is fully opened. . If step S41 is YES, the process proceeds to step S43, and the dissociation amount between the current value of the regulator upstream pressure and the target value is calculated. In step S44, the opening degree of the tank main stop valve 44 is feedback-controlled so that the current value of the regulator upstream pressure matches the target value. The above control may be performed only when it is determined that the time is before the injection of gas fuel is stopped.

FIG. 11 is a time chart for explaining the regulator upstream pressure control process of FIG. 10 more specifically. In FIG. 11, the control target value of the regulator upstream pressure is determined, and the opening degree of the tank main stop valve 44 is feedback-controlled so as to coincide with the target value. At timing t21, an idle flag is set (similar to timing t11 in FIG. 9). In this case, the regulator upstream pressure is maintained near the target value before and after the timing t21.

Thereafter, when an engine stop request is generated by turning off the ignition switch at timing t22, both the tank main stop valve 44 and the shutoff valve 45 are closed, and injection of gas fuel by the first injection valve 21 is stopped. Is done. Even after timing t22, the regulator upstream pressure is maintained near the target value. In this case, the regulator upstream pressure can be maintained at a desired pressure before the engine 10 is stopped, and the pressure regulating valve 60 leaks to the low pressure side of the high pressure side gas fuel via the valve body seat portion (valve seat portion 63). Even so, it is possible to suppress an excessive increase in the injection pressure (the supply gas pressure to the first injection valve 21). Therefore, when the engine is restarted thereafter, it is possible to suppress the inconvenience that the fuel injection of the first injection valve 21 is difficult to be performed due to the injection pressure being too high and the engine start is adversely affected.

Further, in the above configuration, since the configuration in which the valve opening degree can be variably adjusted is used as the tank main stop valve 44, the regulator upstream pressure is stabilized as compared with the case where a configuration in which the valve is fully closed and fully opened is used. As a result, the injection pressure, which is the downstream pressure of the regulator, is stabilized, and air-fuel ratio fluctuations due to pressure fluctuations can be suppressed.

Control of the regulator upstream pressure using the detection results of both the pressure sensor 46 (corresponding to the first pressure sensor) for detecting the regulator upstream pressure and the tank internal pressure sensor 50 (corresponding to the second pressure sensor) for detecting the tank internal pressure. May be implemented. The contents of the processing will be described with reference to FIG. The process in FIG. 12 is obtained by changing a part of the process in FIG. 5, but for the sake of convenience, the process of prohibiting the update of the air-fuel ratio learning value (steps S16 to S18) is omitted.

In FIG. 12, when it is determined that there is a request for switching from gas fuel to liquid fuel, and it is determined that the regulator upstream pressure is equal to or higher than a predetermined determination value K1 (when both steps S11 and S13 are YES). In step S51, the tank internal pressure detected by the tank internal pressure sensor 50 is acquired. In a succeeding step S52, it is determined whether or not the regulator upstream pressure is within a predetermined range lower than the tank internal pressure. At this time, if the regulator upstream pressure is within a pressure range (K1 or more, a pressure range less than the tank internal pressure −β) that is less than “tank internal pressure −β”, step S52 is affirmed. The pressure range may be “K1 or more and less than tank internal pressure”. If step S52 is NO, the tank main stop valve 44 is closed to decrease the regulator upstream pressure, and if step S52 is YES, the tank main stop valve 44 is opened to increase the regulator upstream pressure. By such control, the regulator upstream pressure is maintained at a pressure lower than the tank internal pressure. In this case, it is possible to prevent the regulator upstream pressure from dropping too much.

As each of the

injection valves

21 and 22, an opening adjustment type injection valve whose valve opening (opening area of the injection port) is adjusted continuously or in multiple stages by electrically driving an electromagnetic driving unit (not shown). In this case, the valve opening degree is adjusted by a duty signal input from the control unit 80. At this time, the fuel flow rate per unit time is adjusted according to the valve opening degree of each

injection valve

21, 22, and the fuel (gas fuel, liquid fuel) whose flow rate is adjusted is supplied to the intake port of each cylinder.

In the above embodiment, the

injection valves

21 and 22 are provided for each cylinder of the multi-cylinder engine. However, the

injection valves

21 and 22 may be provided in common for a plurality of cylinders. For example, it is good also as a structure which injects gas fuel and liquid fuel with respect to the collection part of the intake system 11. FIG.

In the above embodiment, gas fuel (CNG) and liquid fuel (gasoline) are used as combustion fuel, but this may be changed and only gas fuel may be used.

In the above embodiment, the CNG fuel is used as the gas fuel, but other gas fuels that are gas in the standard state can also be used. For example, it is possible to use a fuel mainly composed of methane, ethane, propane, butane, hydrogen, DME, or the like. Further, the liquid fuel is not limited to gasoline fuel, and for example, light oil or the like may be used.

Claims

A gas tank (42) for storing gaseous fuel in a high pressure state;
A gas fuel injection valve (21) for injecting gas fuel supplied from the gas tank through the fuel passage (41);
A pressure regulating valve (60) provided in the fuel passage and configured to depressurize and regulate the pressure of the gaseous fuel supplied to the gaseous fuel injection valve;
A shutoff valve (45) provided in the fuel passage upstream and in the vicinity of the pressure regulating valve and having a shutoff function for shutting off the flow of gas fuel;
A fuel injection control device for an internal combustion engine applied to a fuel injection system comprising:
A tank outlet valve (44) provided in the vicinity of the fuel outlet of the gas tank and having a shut-off function for shutting off the flow of gas fuel;
An injection stop determination means (80) for determining whether or not it is a time before fuel injection by the gas fuel injection valve is stopped;
Pressure determining means (80) for determining whether or not the fuel pressure in the high pressure passage (41a, 51) between the gas tank and the pressure regulating valve is equal to or greater than a predetermined value;
When it is determined by the injection stop determination means that the time is before injection stop, and when the pressure determination means determines that the fuel pressure in the high pressure passage portion is equal to or higher than a predetermined value, the gas fuel injection valve An internal combustion engine having pressure control means (80) for reducing the fuel pressure in the high-pressure passage section by opening the shut-off valve, closing the tank outlet valve, or closing or limiting the open state while continuing fuel injection. Fuel injection control device.
2. The fuel for an internal combustion engine according to claim 1, wherein the injection stop determination unit determines that the fuel injection by the gas fuel injection valve is stopped before the gas fuel injection stop request is generated. 3. Injection control device.
A liquid fuel injection valve (22) for injecting liquid fuel;
The injection stop determination means is a time point before the fuel injection by the gas fuel injection valve is stopped when a request for switching from the operation state using the gas fuel to the operation state using the liquid fuel occurs. The fuel injection control device for an internal combustion engine according to claim 1, wherein the fuel injection control device is determined to be present.
Load determining means for determining that the operating load of the internal combustion engine is in a predetermined low load state;
The injection stop determination means determines that it is a time before fuel injection by the gas fuel injection valve is stopped when it is determined that the load determination means is in a low load state. A fuel injection control device for an internal combustion engine according to claim 1.
The tank outlet valve has a function of variably adjusting the valve opening,
The pressure control means controls the valve opening degree of the tank outlet valve so that the fuel pressure in the high-pressure passage is maintained in a predetermined pressure range as control for bringing the tank outlet valve into the open restriction state. Item 5. The fuel injection control device for an internal combustion engine according to any one of Items 1 to 4.
A first pressure sensor (46) provided in the high-pressure passage for detecting fuel pressure in the high-pressure passage, and a second pressure sensor (50) provided in the gas tank for detecting the tank internal pressure;
The pressure determining means determines whether or not the fuel pressure in the high pressure passage portion is equal to or higher than a predetermined value based on the fuel pressure detected by the first pressure sensor;
6. The pressure control unit according to claim 1, wherein the pressure control unit performs control so that the fuel pressure detected by the first pressure sensor falls within a predetermined range lower than the tank internal pressure detected by the second pressure sensor. A fuel injection control device for an internal combustion engine according to claim 1.
Air-fuel ratio feedback control is performed when gas fuel is injected by the gas fuel injection valve, and air-fuel ratio control means is further provided for calculating and updating the learning value in the air-fuel ratio feedback control.
Update for prohibiting updating of the learning value when the pressure control means continues the fuel injection by the gas fuel injection valve and the shut-off valve is in an open state and the tank outlet valve is in a closed state or an open restriction state. The fuel injection control device for an internal combustion engine according to any one of claims 1 to 6, further comprising prohibition means.
An abnormality determining means for determining whether or not there is an abnormality in the fuel supply system of the gaseous fuel based on a fuel pressure in the fuel passage downstream of the tank outlet valve;
In the pressure control means, when the fuel injection by the gas fuel injection valve is continued, the abnormality determination by the abnormality determination means is stopped when the shutoff valve is opened and the tank outlet valve is closed or open restricted. The fuel injection control device for an internal combustion engine according to any one of claims 1 to 7, further comprising stop means for limiting.
A fuel remaining amount estimating means for estimating a fuel remaining amount in the gas tank based on a fuel pressure in the high pressure passage portion or a fuel pressure in the gas tank;
When the pressure control means continues the fuel injection by the gas fuel injection valve and the shut-off valve is in the open state and the tank outlet valve is in the closed state or the open restriction state, the fuel remaining amount estimating means The fuel injection control device for an internal combustion engine according to any one of claims 1 to 8, further comprising estimation prohibiting means for prohibiting estimation of the amount.
A fuel injection system for a vehicle comprising the fuel injection control device for an internal combustion engine according to any one of claims 1 to 9,
The internal combustion engine, the gas tank, the gas fuel injection valve, the pressure regulating valve, the shutoff valve, and the tank outlet valve,
The internal combustion engine, the gas fuel injection valve, the pressure regulating valve, and the shutoff valve are mounted on a front portion of the vehicle, and the gas tank and the tank outlet valve are mounted on a rear portion of the vehicle. Injection system.