Fuel injection system

Abstract

Fuel injection system comprising (i) a plurality of injectors, the plurality of injectors comprising at least two injectors (40, 50), the plurality of injectors being configured to inject gaseous fuel into an engine (20), (ii) a fuel tank (30) being configured to store gaseous fuel, and (iii) a delivery line (312, 313) being configured to supply gaseous fuel from the fuel tank to each of the plurality of injectors, the fuel injection system comprising: a wear amount estimation unit (72) configured to estimate a wear amount of each of the plurality of injectors; and a determination unit (73) configured to determine, based on the wear amount of each of the plurality of injectors estimated by the wear amount estimation unit, which of the plurality of injectors is preferably operated; and wherein the wear amount estimation unit is further configured to estimate the wear amount of each of the plurality of injectors based on a cumulative number of operating cycles of each of the plurality of injectors; and wherein The determining unit is further configured to calculate a subtraction value, obtained by subtracting the cumulative number of operating operations from a predetermined number of operating operations, for each of the plurality of injectors and preferably to operate one of the plurality of injectors that has the largest subtraction value.

Description

Technical field

[0001] The present disclosure relates to a fuel injection system. background

[0002] A vehicle fuel injection system is known, which is described in the following patent reference 1. In the fuel injection system described in patent reference 1, compressed natural gas (hereinafter referred to as "CNG") is used as fuel for an internal combustion engine, wherein the CNG fuel is injected into the internal combustion engine by an injector. In the fuel injection system described in patent reference 1, when the fuel temperature difference between the cylinders of an internal combustion engine is within a predetermined permissible range during stratified combustion, the fuel injection control of the internal combustion engine is carried out by correcting the fuel injection quantity and the fuel injection timing based on the average temperature and pressure of the fuel.Furthermore, if the fuel temperature difference between the cylinders is outside the predetermined permissible range during stratified combustion, this fuel injection system switches to homogeneous combustion, corrects the injection quantity based on the average temperature and pressure of the fuel, and controls the fuel injection of the internal combustion engine. State-of-the-art literature, patent literature

[0003] Patent Literature 1: JP 2005-240581 A

[0004] DE 10 2018 104 856 A1 discloses a method for operating an internal combustion engine, wherein fuel can be supplied to a combustion chamber via a number of injectors greater than or equal to two. In partial-load operation, the combustion chamber is supplied with fuel via a number of injectors less than two. Injection events of the individual injectors are each recorded by a counter, whereby the individual injectors are controlled in partial-load operation depending on the counter reading. A fuel injection system of an internal combustion engine is further described, in which fuel can be supplied to a combustion chamber via at least two injectors, wherein a control device for controlling the injectors is provided, which includes a storage device for counting the injection events of the individual injectors. The control device is designed to carry out such a method.

[0005] DE 10 2016 201 428 A1 relates to a two-fuel fuel injector for an internal combustion engine, comprising a first injection device for injecting a first fuel, and at least a second injection device arranged radially outward from the first injection device for injecting a second fuel, wherein the second fuel is different from the first fuel, and comprising a first connection for supplying the first fuel and a second connection for supplying the second fuel. It is provided that the first connection is fluidly connected to the first injection device for supplying the gaseous first fuel, and the second connection is fluidly connected to the second injection device for supplying the liquid second fuel. Summary of the invention

[0006] When liquid fuel is used as fuel for the internal combustion engine, the injector can be lubricated by the liquid fuel at interfaces.

[0007] The fuel injection system described in patent literature 1 uses a gaseous fuel, such as CNG, as fuel for the internal combustion engine. In this case, it becomes difficult to achieve boundary lubrication of the injector with the fuel. Therefore, in a fuel injection system using gaseous fuel, wear in the sliding section of the injector is expected to be accelerated. Thus, there is room for improvement regarding the injector's service life.

[0008] One objective of the present disclosure is to provide a fuel injection system that can improve the longevity of an injector that injects gaseous fuel.

[0009] This problem is solved by the fuel injection systems with the features of the independent claims, and advantageous further developments of the invention are the subject of the subsequent claims.

[0010] According to an example in the present disclosure, a fuel injection system is provided which includes: (i) a plurality of injectors, comprising at least two injectors, the plurality of injectors being configured to inject gaseous fuel into an engine, (ii) a fuel tank configured to store the gaseous fuel, and (iii) a delivery line configured to supply the gaseous fuel from the fuel tank to each of the plurality of injectors. The fuel injection system further includes (i) a wear estimation unit and (ii) a determination unit. The wear estimation unit is configured to estimate the wear of each of the plurality of injectors.The determination unit is configured to determine, based on the wear amount of each injector from the plurality of injectors estimated by the wear amount estimation unit, which injector from the plurality of injectors is preferably operated.

[0011] According to this configuration, it is possible to preferentially operate a more suitable injector based on the degree of wear of multiple injectors. Therefore, the service life of the injector that injects gaseous fuel can be improved. Brief description of the drawings Fig. 1 is a diagram that schematically shows a configuration of a fuel injection system according to a first embodiment; Fig. 2 is a block diagram showing an electrical configuration of the fuel injection system according to the first embodiment; Fig. Figure 3 is a flowchart showing a processing sequence carried out by a control device according to the first embodiment; Fig. Figure 4 is a flowchart showing a processing sequence carried out by a control device according to a second embodiment; Fig. Figure 5 is a flowchart showing a processing sequence carried out by a control device according to a third embodiment; Fig. Figure 6 is a flowchart showing a processing sequence carried out by a control device according to a fourth embodiment; Fig. Figure 7 is a flowchart showing a processing sequence carried out by a control device according to a fifth embodiment; Fig. Figure 8 is a flowchart showing a processing sequence carried out by a control device according to a sixth embodiment; Fig. Figure 9 is a flowchart showing a processing sequence carried out by a control device according to a first modified example of the sixth embodiment; Fig. Figure 10 is a flowchart showing a processing sequence carried out by a control device according to a second modified example of the sixth embodiment; Fig. Figure 11 is a flowchart showing a processing sequence carried out by a control device according to a third modified example of the sixth embodiment; Fig. Figure 12 is a flowchart showing a processing sequence carried out by a control device according to a fourth modified example of the sixth embodiment; Fig. Figure 13 is a flowchart showing a processing sequence carried out by a control device according to a seventh embodiment; Fig. Figure 14 is a flowchart showing a processing sequence carried out by a control device according to an eighth embodiment; and Fig. Figure 15 is a flowchart showing a processing sequence carried out by a control device according to a ninth embodiment. Embodiments for carrying out the invention

[0012] The following describes the embodiments of a fuel injection system with reference to the drawings. For clarity, the same reference numerals are used for the same components in the drawings where possible, omitting redundant explanations. First embodiment

[0013] First, a fuel injection system 10 according to a first embodiment, which is in Fig. Figure 1 is shown and described. The fuel injection system 10, which is in Fig. Figure 1 shows a system for injecting fuel into an internal combustion engine 20 of a vehicle. A gaseous fuel, such as CNG (compressed natural gas), is used as the fuel for the internal combustion engine 20 of the present embodiment. It should be noted that Fig. Figure 1 shows only a single cylinder 21 from the plurality of cylinders provided in the internal combustion engine 20. The fuel injection system 10 includes a fuel tank 30, a bore-type injection injector 40, and a direct injection injector 50.

[0014] High-pressure gas fuel is stored in fuel tank 30. A fuel line 31 is connected to fuel tank 30. From a midpoint, fuel line 31 branches into a first branch line 310 and a second branch line 311. A first delivery line 312 is connected to the tip of the first branch line 310. A second delivery line 313 is connected to the tip of the second branch line 311. The high-pressure gas fuel stored in fuel tank 30 is supplied to the first delivery line 312 and the second delivery line 313 via fuel line 31. The first delivery line 312 supplies gas fuel to the open-circuit injection injector 40, which is provided in each cylinder 21 of the internal combustion engine 20. The second delivery line 313 supplies gas fuel to the direct injection injector 50, which is provided in each cylinder 21 of the internal combustion engine 20.

[0015] Fuel line 31 is equipped with a fuel shut-off valve 32 and a regulating device 33. Furthermore, the first branch line 310 is equipped with a regulating device 34. The fuel shut-off valve 32 can switch between supplying and shutting off gas fuel from the fuel tank 30 to the delivery lines 312 and 313 by opening and closing. The regulating device 33 can adjust the pressure of the gas fuel supplied from the fuel tank 30 to the second delivery line 313 by changing its opening degree. The regulating device 34 can adjust the pressure of the gas fuel supplied from the fuel tank 30 to the first delivery line 312 by changing its opening degree.

[0016] The open-circuit injection injector 40 is located in the intake port 22 of the internal combustion engine 20. The open-circuit injection injector 40 injects the gaseous fuel supplied by the first delivery line 312 into the intake port 22. The gaseous fuel injected by the open-circuit injection injector 40, together with air flowing in the intake port 22, is introduced into the combustion chamber 210 in the cylinder 21.

[0017] The direct injection injector 50 is located in cylinder 21 of the internal combustion engine 20. The direct injection injector 50 injects gaseous fuel, supplied by the second delivery line 313, directly into the combustion chamber 210 in cylinder 21. It should be noted that each cylinder 21 of the internal combustion engine 20 is equipped with one open-circuit injection injector 40 and one direct injection injector 50. The open-circuit injection injector 40 and the direct injection injector 50 are each located at two corresponding positions, which are arranged identically in each of the multiple cylinders in the engine.

[0018] Air is introduced into the combustion chamber 210 of each cylinder 21 of the internal combustion engine 20 via the intake valve 23 through the intake port 22. Gaseous fuel, injected by the open-circuit injector 40 or the direct-injection injector 50, is also introduced into the combustion chamber 210. In the internal combustion engine 20, the air-fuel mixture combusts in the combustion chamber 210, causing the pistons 211 in each cylinder 21 to move back and forth. This generates the driving force of the internal combustion engine 20. The exhaust gas produced by the combustion of the air-fuel mixture in the combustion chamber 210 is discharged to the exhaust port 25 of the internal combustion engine 20 via the exhaust valve 24.

[0019] Next, the electrical configuration of the fuel injection system 10 is described. As in Fig. As shown in Figure 1, the fuel tank 30 is equipped with a pressure sensor 60. The pressure sensor 60 detects the fuel pressure of the fuel tank 30, more precisely, the pressure of the gaseous fuel stored in the fuel tank 30, and outputs a signal corresponding to the detected fuel pressure of the fuel tank 30.

[0020] A pressure sensor 61 is provided on the first delivery line 312. The pressure sensor 61 detects the pressure of the gas fuel inside the first delivery line 312, in other words, the fuel injection pressure of the orifice injection injector 40, and outputs a signal according to the detected gas fuel pressure.

[0021] A pressure sensor 62 is provided in the second delivery line 313. The pressure sensor 62 detects the pressure of the gaseous fuel inside the second delivery line 313, in other words, the fuel injection pressure of the direct injection injector 50, and outputs a signal corresponding to the detected gaseous fuel pressure. As in Fig. As shown in Figure 2, the output signals from pressure sensors 60 to 62 are received by the control device 70. The control device 70 consists mainly of a microcomputer with a CPU, memory, and the like. The control device 70 includes non-volatile memory 71 for storing various types of information. The control device 70 can obtain information on the fuel pressure of the fuel tank 30, the fuel injection pressure of the orifice-flow injector 40, and the fuel injection pressure of the direct injection injector 50 based on the output signals from the pressure sensors 60 to 62.

[0022] Furthermore, the control device 70 receives the output signals from sensors 63 installed in the vehicle. The sensor 63 installed in the vehicle includes a sensor that detects the amount of depressurization of the accelerator pedal, a crank angle sensor that detects the rotation angle of the crankshaft of the internal combustion engine 20, a flow rate sensor that detects the amount of intake air corresponding to the flow rate of the air flowing through the intake passage 22, a temperature sensor that detects the temperature of the exhaust gas flowing through the exhaust passage 25, and a temperature sensor that detects the temperature of the coolant of the internal combustion engine 20.

[0023] The control device 70 controls the orifice-flow injector 40 and the direct-injection injector 50 of each cylinder 21 based on the various pieces of information acquired by sensors 60 to 63. Accordingly, fuel injection control is performed to regulate the amount of fuel injected into each cylinder 21. It should be noted that the injectors 40 and 50 cannot be lubricated by the fuel interfaces when gaseous fuel is used as fuel for the internal combustion engine 20. Therefore, the sliding surfaces of the injectors 40 and 50 are expected to wear more than when liquid fuel is used as fuel for the internal combustion engine 20. If the sliding surfaces of the injectors 40 and 50 are worn, the amount of fuel injected by the injectors 40 and 50 will vary, and the fuel injection control will not function correctly.

[0024] On the other hand, the amount of wear on each injector 40, 50 is fundamentally correlated with the number of operating cycles of each injector 40, 50. Therefore, in the fuel injection system 10 of the present embodiment, the amount of wear on each injector 40, 50 is estimated based on the number of operating cycles of each injector 40, 50. Subsequently, in the fuel injection system 10 of the present embodiment, the injector with the fewest operating cycles is preferably activated by the open-circuit injection injector 40 and the direct injection injector 50. This improves the service life of the overall system.

[0025] In particular, the control device 70 includes, as shown in Fig. Figure 2 shows a wear estimation unit 72 and a determination unit 73. The wear estimation unit 72 counts the cumulative number of operating cycles of each injector 40, 50 as an estimated wear value for each injector 40, 50. The cumulative number of operating cycles is the total number of operating cycles since the injectors 40 and 50 were first activated. Specifically, the non-volatile memory 71 stores the cumulative number of operating cycles NP of the open-circuit injection injector 40 and the cumulative number of operating cycles ND of the direct injection injector 50. The respective values ​​of the cumulative number of operating cycles NP and ND are set to zero at the beginning of the activation of the injectors 40 and 50. The wear amount estimation unit 72 increments the value of the cumulative number of operating operations NP each time the open-circuit injection injector 40 is activated.Furthermore, the wear amount estimation unit 72 increments the value of the cumulative number of operating cycles ND each time the direct injection injector 50 is activated. The power supply to the control device 70 can be disconnected from the battery after the vehicle has been stopped. Even in such a case, it is possible to maintain the information about the cumulative number of operating cycles NP and ND by storing them in the non-volatile memory 71.

[0026] The determination unit 73 determines, based on the cumulative number of operating cycles NP and ND of the respective injectors 40 and 50, which are stored in the non-volatile memory 71, which is preferably operated by the open-circuit injection injector 40 and the direct injection injector 50. Next, with reference to Fig. 3 The processing procedure carried out by the determination unit 73 is described in more detail.

[0027] As in Fig. As shown in Figure 3, the determining unit 73, in processing step S10, first reads the maximum number of operating cycles NPmax and NDmax of injectors 40 and 50 from the non-volatile memory 71. The maximum number of operating cycles NPmax and NDmax are the maximum values ​​for the number of operating cycles of injectors 40 and 50 that do not cause an unacceptable change in performance. The maximum number of operating cycles NPmax and NDmax are set through experimentation and the like and pre-stored in the non-volatile memory 71. If the orifice-jet injection injector 40 and the direct injection injector 50 have different structures, the maximum number of operating cycles NPmax and NDmax may be set to different values. In the present embodiment, each of the maximum number of operating cycles NPmax and NDmax corresponds to a predetermined number of operating cycles.

[0028] The determination unit 73 reads the cumulative number of operating operations NP and ND of injectors 40 and 50 from the non-volatile memory 71 as the processing of step S11, which follows step S10. Subsequently, as the processing of step S12, the determination unit 73 calculates the number of permissible operating operations NPc and NDc of injectors 40 and 50 based on the following equations f1 and f2. NPc=NPmax−NP NDc=NDmax−ND

[0029] In the processing step S13, which follows step S12, the determining unit 73 determines, based on the number of permissible operating cycles NPc and NDc of the respective injectors 40 and 50, which is preferably operated by the orifice-flow injector 40 and the direct injection injector 50. In particular, the determining unit 73 preferably operates the orifice-flow injector 40 if the number of permissible operating cycles NPc of the orifice-flow injector 40 is greater than the number of permissible operating cycles NDc of the direct injection injector 50. Furthermore, the determining unit 73 preferably operates the direct injection injector 50 if the number of permissible operating cycles NDc of the direct injection injector 50 is greater than the number of permissible operating cycles NPc of the orifice-flow injector 40.If the number of permissible operating cycles NPc of the orifice injection injector 40 and the number of permissible operating cycles NDc of the direct injection injector 50 have the same value, the determining unit 73 decides to operate either the orifice injection injector 40 or the direct injection injector 50.

[0030] After completing the processing of step S13, the destination unit 73 completes a series of processing operations that are described in Fig. 3 are shown. The determination unit 73 carries out the processing that is in Fig. As shown in 3, each cylinder from the majority of cylinder 21 of the internal combustion engine 20 is individually processed.

[0031] According to the fuel injection system 10 of the present embodiment, which has been described above, the processes and effects shown below, (1) and (2), can be achieved. (1) A more suitable injector can preferably be operated according to the amount of wear of each orifice-jet injection injector 40 and direct injection injector 50. Therefore, the service life of the injectors 40 and 50 that inject gaseous fuel can be improved. (2) The wear estimation unit 72 estimates the wear amount of each injector 40, 50 based on the cumulative number of operating cycles NP, ND of each injector 40, 50. As shown in the preceding equations f1 and f2, the determination unit 73 calculates a subtraction value obtained by subtracting the cumulative number of operating cycles NP, ND from the maximum number of operating cycles NPmax, NDmax for each of the injectors 40 and 50. The injector with the largest subtraction value is preferably operated. According to such a configuration, an injector with sufficient durability is readily and preferably operated. Second embodiment

[0032] Next, a second embodiment of the fuel injection system 10 is described. The differences between this embodiment and the fuel injection system 10 of the first embodiment are mainly described below. As in Fig. As shown in Figure 4, the determining unit 73 of the present embodiment calculates the ratios of the cumulative operating processes NPr and NDr of the injectors 40 and 50 based on the following equations f3 and f4 as the processing of step S14 following the processing of step S11. NPr=NP / NPmax NDr=ND / NDmax

[0033] In the processing of step S13, which follows step S14, the determining unit 73 determines, based on the ratios of the cumulative operating events NPr and NDr of the injectors 40 and 50, which is preferably operated by the orifice-flow injector 40 and the direct-injection injector 50. In particular, the determining unit 73 preferably operates the orifice-flow injector 40 if the ratio of the cumulative operating events NPr of the orifice-flow injector 40 is less than the ratio of the cumulative operating events NDr of the direct-injection injector 50. Furthermore, the determining unit 73 preferably operates the direct-injection injector 50 if the ratio of the cumulative operating events NDr of the direct-injection injector 50 is less than the ratio of the cumulative operating events NPr of the orifice-flow injector 40.If the ratio of the cumulative operating events NPr of the orifice injection injector 40 and the ratio of the cumulative operating events NDr of the direct injection injector 50 have the same value, the determining unit 73 decides to operate either the orifice injection injector 40 or the direct injection injector 50.

[0034] According to the fuel injection system 10 of the present embodiment described above, the processes and effects shown below, (3), can be achieved instead of the processes and effects shown previously in (2).

[0035] (3) As shown in the preceding equations f3 and f4, the determining unit 73 calculates a division value obtained by dividing the cumulative number of operating cycles NP, ND by the maximum number of operating cycles NPmax, NDmax for each of the injectors 40 and 50, and preferably operates the injector with the smallest division value. According to such a configuration, an injector with sufficient durability is readily and preferably operated. Third embodiment

[0036] Next, a third embodiment of the fuel injection system 10 is described. The differences between this embodiment and the fuel injection system 10 of the first embodiment are mainly described below. The determination unit 73 of the first embodiment performs the determination processing of the preferably operated injector, which is carried out in Fig. As shown in Figure 3, this process is carried out individually for each of the multiple cylinders 21 of the internal combustion engine 20. On the other hand, the determination unit 73 of the present embodiment performs the determination processing, which is described in Figure 3. Fig. As shown in Figure 3, the procedure is carried out for a specific cylinder from the plurality of cylinders 21. At the same time, using the determination result for other cylinders that are different from the specific cylinder, the preferably operated injector is determined for the other cylinders.

[0037] In particular, as in Fig. As shown in Figure 5, the determination unit 73, as the processing of step S15, first performs the determination processing of the preferably operated injector, which is in Fig. Figure 3 shows that this is carried out only for a specific cylinder from the plurality of cylinders 21 of the internal combustion engine 20. For the specific cylinder, it is determined which of the orifice injection injector 40 and the direct injection injector 50 is a preferably operated injector.

[0038] Next, the determination unit 73, as part of the processing of step S16, considers the determination result of the injector (i.e., the preferably operated injector) determined in the processing of step S15 for other cylinders other than the specific cylinder. Accordingly, the preferably operated injector is determined for each of the other cylinders to be the injector located at the same corresponding position, as defined in the identical arrangement, as the corresponding position defined in the identical arrangement of the preferably operated injector determined for the specific cylinder.

[0039] Furthermore, according to the fuel injection system 10 of the present embodiment described above, the processes and effects shown below, (4) can be achieved.

[0040] (4) Since the process of determining the preferably operated injector is only carried out for one specific cylinder from the plurality of cylinders 21, the determination process can be simplified. Furthermore, preferably the same injector is operated in each of the plurality of cylinders 21. Therefore, it is possible to suppress variations in the service life of injectors 40 and 50 across the plurality of cylinders 21. Fourth embodiment

[0041] Next, a fourth embodiment of the fuel injection system 10 is described. The differences from the fuel injection system 10 of the first embodiment are mainly described below. The internal combustion engine 20, which has a structure that is in Fig. As shown in Figure 1, the filling efficiency can be improved by injecting gas fuel from the direct injection injector 50 instead of the orifice injection injector 40, in order to improve the output and fuel consumption of the internal combustion engine 20. Therefore, in a situation where the load of the internal combustion engine 20 is high, it is desirable to preferably operate the direct injection injector 50 instead of the orifice injection injector 40. Therefore, the determining unit 73 of the present embodiment, regardless of the order of magnitude of the number of permissible operating cycles NPc and NDc, preferably operates the direct injection injector 50 when the load of the internal combustion engine 20 is greater than or equal to a predetermined value.

[0042] In particular, as in Fig. As shown in Figure 6, the determining unit 73, in step S20, first determines whether the load Le of the internal combustion engine 20 is greater than or equal to the predetermined value Lth. The load Le of the internal combustion engine 20 is a numerical value representing the load state of the internal combustion engine 20. The load state of the internal combustion engine 20 correlates, for example, with the rotational speed of the internal combustion engine 20 or the amount of intake air. The determining unit 73 calculates the load Le of the internal combustion engine 20 from the rotational speed of the internal combustion engine 20 or the amount of intake air detected by the sensor 63 installed in the vehicle, using a map or similar method. The load Le of the internal combustion engine 20 is set such that its value increases when the internal combustion engine 20 enters a high-load state and decreases when the internal combustion engine 20 enters a low-load state.

[0043] Consider a case where the determination unit 73 performs a negative determination during the processing of step S20, i.e., when the load Le of the internal combustion engine 20 is lower than the predetermined value Lth. In such a case, the determination unit 73, as the processing of step S22, performs the determination processing of the preferably operated injector, as shown in Fig. Figure 3 shows. Subsequently, the determining unit 73, as part of the processing of step S23, injects gaseous fuel via the preferably operated injector, which was determined in the processing of step S22.

[0044] Consider a case in which the determination unit 73 performs a positive determination during the processing of step S20, i.e., when the load Le of each internal combustion engine 20 is equal to or greater than the predetermined value Lth. In such a case, the determination unit 73 injects gas fuel via the direct injection injector 50 as part of the processing of step S21. According to the fuel injection system 10 of the present embodiment described above, the processes and effects shown below, (5), can also be achieved.

[0045] (5) Suppose a case in which, based on the number of permissible operating cycles NPc and NDc, the orifice-flow injection injector 40 is to be operated preferentially. Even then, gaseous fuel is injected via the direct-injection injector 50, irrespective of the magnitudes of the number of permissible operating cycles NPc and NDc, if the load Le of the internal combustion engine 20 is greater than or equal to the predetermined value Lth. According to such a configuration, the filling efficiency can be improved by injecting gaseous fuel via the direct-injection injector 50 when the load of the internal combustion engine 20 is high. Therefore, the power consumption and output of the internal combustion engine 20 can be improved. Fifth embodiment

[0046] Next, a fifth embodiment of the fuel injection system 10 is described. The differences between this embodiment and the fuel injection system 10 of the first embodiment are described below. With the direct injection injector 50, no gaseous fuel can be injected as long as the injection pressure is higher than the pressure in the combustion chamber 210. Furthermore, even if the injection pressure is higher than the pressure in the combustion chamber 210, the difference between the injection pressure and the pressure in the combustion chamber 210 decreases as a result of the reduction in injection pressure. In such a case, the injection quantity of the direct injection injector 50 is reduced; therefore, there is a possibility that an insufficient amount of gaseous fuel will be injected.Therefore, the injection quantity of the direct injection injector 50 tends to be insufficient if the fuel pressure in the fuel tank 30 decreases as a result of the reduction in the amount of gas fuel remaining in the fuel tank 30. Consequently, the performance of the internal combustion engine 20 may deteriorate, and it will become difficult to use up the gas fuel in the fuel tank 30.

[0047] On the other hand, consider a case in which the fuel pressure in the fuel tank 30 drops to a level where it becomes difficult to inject fuel from the direct injection injector 50 into the combustion chamber 210. Even then, the orifice injection injector 40 can inject sufficient fuel. Therefore, the determining unit 73 of the present embodiment is configured, regardless of the number of permissible operating cycles NPc and NDc, to preferably operate the orifice injection injector 40 when the fuel pressure in the fuel tank 30 is equal to or less than a predetermined value.

[0048] In particular, as in Fig. As shown in Figure 7, the determination unit 73, as the processing step S24, first determines whether the fuel pressure Pf of the fuel tank 30, detected by the pressure sensor 60, is equal to or less than the predetermined value Pth. Consider a case in which the determination unit 73 performs a negative determination during the processing step S24, i.e., when the fuel pressure Pf of the fuel tank 30 exceeds the predetermined value Pth. In this case, the processing step S22 is the determination processing of the preferably operated injector, which is described in Figure 60. Fig. As shown in 3, the process is carried out. Subsequently, the determining unit 73, as part of the processing of step S23, injects gaseous fuel via the preferably operated injector, which was determined in the processing of step S22.

[0049] It is assumed that the determining unit 73 performs a positive determination during the processing of step S24, i.e., when the fuel pressure Pf of the fuel tank 30 is equal to or less than the predetermined value Pth. In such a case, the determining unit 73 injects gas fuel via the orifice injection injector 40 as part of the processing of step S31. According to the fuel injection system 10 of the present embodiment described above, the processes and effects shown below in (6) can also be achieved.

[0050] (6) Suppose a case in which the direct injection injector 50 is to be operated preferentially based on the number of permissible operating cycles NPc and NDc. Even in such a case, regardless of the magnitude of the number of permissible operating cycles NPc and NDc, gas fuel is injected by the orifice injection injector 40 when the fuel pressure Pf of the fuel tank 30 is less than or equal to the predetermined value Pth. According to such a configuration, gas fuel is injected by the orifice injection injector 40 when the fuel pressure Pf of the fuel tank 30 is low. The gas fuel in the fuel tank 30 can thus be used more reliably. Consequently, the vehicle's range can be extended.When gas fuel is injected by the orifice-gate injector 40, the filling efficiency is lower than when gas fuel is injected by the direct-injection injector 50. Therefore, there is a concern that the output of the internal combustion engine 20 may be reduced. To solve this problem, it is effective to increase the output of the internal combustion engine 20, for example, by increasing the gear ratio of the vehicle's transmission and by shifting the operating point of the internal combustion engine 20 to the high-speed side. Sixth embodiment

[0051] Next, a sixth embodiment of the fuel injection system 10 is described. The differences from the fuel injection system 10 of the first embodiment are mainly described below. If the intended processing for the preferably operated injector, which is in Fig. As shown in Figure 3, if the injector injecting fuel is operated constantly, it can be switched to each combustion cycle of the internal combustion engine 20. This means that the amount of fuel injected can vary from one combustion cycle to the next. Therefore, it is not desirable to perform the determination process of the preferably operated injector frequently. It is desirable that the determination process of the preferably operated injector be carried out at a time interval of a specific length. Therefore, the determination process of the preferably operated injector, which is shown in Figure 3, is performed at a specific interval. Fig. Figure 3 shows that the fuel injection system 10 of the present embodiment is carried out at predetermined time intervals.

[0052] In particular, the determination unit 73 of the present embodiment carries out the processing which Fig. As shown in 8, it occurs in a predetermined calculation cycle. As in Fig. As shown in Figure 8, the determination unit 73, as the processing step of S40, first determines whether a predetermined time has elapsed since the previous determination time of the preferably operated injector. Consider a case in which the determination unit 73 performs a positive determination during the processing of step S40, i.e., when a predetermined time has elapsed since the previous determination time of the preferably operated injector. In such a case, the determination unit 73, as the processing of step S41, performs the determination processing of the preferably operated injector, which is described in Figure 8. Fig. As shown in Figure 3, the determination unit 73 determines the preferably operated injector during the processing of step S41 and counts the elapsed time since the determination time.

[0053] If the determining unit 73 performs a negative determination during the processing of step S40, i.e., if a predetermined time has not elapsed since the previous determination time of the preferably operated injector, the processing of step S41 is not carried out. That is, the determining unit 73 does not determine the preferably operated injector. According to the fuel injection system 10 of the present embodiment, which has been described above, the effects and results shown below in (7) can also be achieved.

[0054] (7) Since the preferred injector is determined at predetermined time intervals, it is possible to avoid frequent injector switching. Consequently, it is possible to suppress fluctuations in the fuel injection quantity for each fuel cycle, thereby preventing adverse effects on driving performance and the like. (First modified example)

[0055] Next, a first modified example of the fuel injection system 10 of the sixth embodiment is described. As in Fig. As shown in Figure 9, in the fuel injection system 10 of the present modification, the processing to determine whether the internal combustion engine 20 has been started or not is carried out as the processing of step S40. Even with such a configuration, the preferably operated injector can be determined at predetermined time intervals. Therefore, the same or similar processes and effects as those previously shown in Figure (7) can be achieved. (Second modified example)

[0056] Next, a second modification of the fuel injection system 10 of the sixth embodiment is described. As in Fig. As shown in Figure 10, in the fuel injection system 10 of the present modification, the processing to determine whether the internal combustion engine 20 has been stopped or not is carried out as the processing of step S40. Even with such a configuration, the preferably operated injector is determined at predetermined time intervals. Therefore, the same or similar processes and effects as those previously shown in Figure (7) can be achieved. (Third modified example)

[0057] Next, a third modified example of the fuel injection system 10 of the sixth embodiment is described. As in Fig. As shown in Figure 11, in the fuel injection system 10 of the present modification, the processing to determine whether the vehicle has stopped or not is performed as the processing of step S40. Even in such a configuration, the preferably operated injector is determined at predetermined time intervals. Therefore, the same or similar processes and effects as those previously shown in Figure (7) can be achieved. (Fourth modified example)

[0058] Next, a fourth modification of the fuel injection system 10 of the sixth embodiment is described. As in Fig. As shown in Figure 12, in the fuel injection system 10 of the present modification, the processing to determine whether the fuel cut-off control of the internal combustion engine 20 is executed or not is performed as the processing of step S40. Even in such a configuration, the preferably operated injector is determined at predetermined time intervals. Therefore, the same or similar processes and effects as those previously shown in Figure (7) can be achieved. Seventh embodiment

[0059] Next, a seventh embodiment of the fuel injection system 10 is described. The main differences compared to the fuel injection system 10 of the first embodiment are described below. To suppress characteristic curve changes of the orifice injection injector 40, it is desirable to replace the orifice injection injector 40 in a situation where the cumulative number of operating cycles NP of the orifice injection injector 40 is less than the maximum number of operating cycles NPmax. Therefore, in the fuel injection system 10 of the present embodiment, a warning count is provided, which has a value that is less than the maximum number of operating cycles NPmax. In the previous embodiment, when the cumulative number of operating cycles NP of the orifice injection injector 40 reaches the warning count, a warning is triggered, prompting the replacement of the orifice injection injector 40.The same applies to the direct injection injector 50.

[0060] In particular, as indicated by the dashed line in Fig. Figure 2 shows the control device 70 and a warning device 80, which can trigger a warning to request the replacement of injectors 40 and 50. The warning device 80 can, for example, be a warning light provided on the vehicle's dashboard.

[0061] The control device 70 further includes a warning unit 74, which performs the processing to trigger a warning to request the replacement of injectors 40 and 50 via the warning device 80. In particular, the warning unit 74 performs the processing that is Fig. 13 is shown, through. As in the Fig. As shown in Figure 13, the warning unit 74, as part of the processing of step S50, first reads the warning counts NPth and NDth of injectors 40 and 50 from the non-volatile memory 71. The warning count NPth of the open-circuit injection injector 40 is set to a value that is less than the maximum number of operating cycles NPmax of the open-circuit injection injector 40. Furthermore, the warning count NDth of the direct injection injector 50 is set to a value that is less than the maximum number of operating cycles NDmax of the direct injection injector 50. In the present embodiment, each of the warning counts NPth and NDth corresponds to a predetermined number of operating cycles.

[0062] The warning unit 74 reads the cumulative number of operating cycles NP and ND of injectors 40 and 50 from the non-volatile memory 71 as part of the processing of step S51, which follows step S50. Subsequently, as part of the processing of step S52, the warning unit 74 determines whether the cumulative number of operating cycles NP is equal to or greater than the warning count NPth, NDth. The warning unit 74 makes a positive determination during the processing of step S52 if the cumulative number of operating cycles NP of the open-circuit injection injector 40 is equal to or greater than the warning count NPth, or if the cumulative number of operating cycles NP of the direct injection injector 50 is equal to or greater than the warning count NDth.

[0063] If the warning unit 74 makes a positive decision during the processing of step S52, the warning device 80 triggers a warning during the processing of step S53. Specifically, if the cumulative number of operating cycles NP of the open-circuit injector 40 is equal to or greater than the warning count NPth, the warning unit 74 triggers a warning via the warning device 80 to request the replacement of the open-circuit injector 40. Furthermore, if the cumulative number of operating cycles ND of the direct-injection injector 50 is equal to or greater than the warning count NDth, the warning unit 74 triggers a warning via the warning device 80 to request the replacement of the direct-injection injector 50.

[0064] Furthermore, according to the fuel injection system 10 of the present embodiment described above, the effects and results shown below, (8) can be achieved.

[0065] (8) It is possible to request the replacement of injectors 40 and 50 before the cumulative number of operating cycles NP, ND of injectors 40 and 50 reaches the maximum number of operating cycles NPmax. Therefore, it is possible to avoid using injectors that could impair performance. Therefore, reliability can be ensured. Eighth embodiment

[0066] Next, an eighth embodiment of the fuel injection system 10 is described. The differences from the fuel injection system 10 of the seventh embodiment are mainly described below. The determining unit 73 of the present embodiment performs the processing that is described in Fig. 14 is shown, through. As in Fig. As shown in Figure 14, the determination unit 73, as the processing unit of step S60, first reads the maximum number of operating operations NPmax and NDmax of injectors 40 and 50 from the non-volatile memory 71. Subsequently, as the processing unit of step S61, the determination unit 73 reads the cumulative number of operating operations NP and ND of injectors 40 and 50 from the non-volatile memory 71.

[0067] The determination unit 73, as the processing of step S62, which follows step S61, determines whether the cumulative number of operating operations NP, ND of each injector 40, 50 has reached the maximum number of operating operations NPmax, NDmax or not. If the determination unit 73 makes a positive determination during the processing of step S62, the determination unit 73, as the processing of step S63, determines whether there is an injector whose cumulative number of operating operations has not reached the maximum number of operating operations or not.

[0068] If the determination unit 73 makes a positive determination during the processing of step S63, the determination unit 73, as processing of step S64, preferably operates the injector whose cumulative number of operating cycles has not reached the maximum number of operating cycles and, as processing of step S63, prevents the injector whose cumulative number of operating cycles has reached the maximum number of operating cycles from being operated. For example, consider a case in which the cumulative number of operating cycles NP of the orifice-gate injection injector 40 is equal to or greater than the maximum number of operating cycles NPmax and the cumulative number of operating cycles ND of the direct injection injector 50 is less than the maximum number of operating cycles NDmax.In such a case, the determining unit 73 preferably operates the direct injection injector 50, preventing the operation of the orifice injection injector 40.

[0069] On the other hand, the determination unit 73, as the processing of step S66, carries out the determination processing of the preferably operated injector, which in Fig. As shown in Figure 2, this occurs when the determining unit 73 performs a negative determination during the processing of step S63. This determines the preferably operated injector. According to the fuel injection system 10 of the present embodiment, which has been described previously, the effects and results shown below in Figure 9 can be achieved.

[0070] (9) Since it becomes difficult to use an injector whose cumulative number of operating cycles has reached the maximum number of operating cycles, reliability can be further improved. Ninth embodiment

[0071] Next, a ninth embodiment of the fuel injection system 10 is described. The differences between this embodiment and the fuel injection system 10 of the first embodiment are mainly described below.

[0072] As indicated by the dotted line in Fig. As shown in Figure 2, the injectors 40 and 50 of the present embodiment are provided with identification information storage units 41 and 51. The identification information IDp and IDd is stored in the identification information storage units 41 and 51, respectively. The identification information IDp is information by which each individual orifice-jet injection injector 40 can be identified. The identification information IDd is information by which each individual direct injection injector 50 can be identified. An IC chip can, for example, be used as the identification information storage units 41 and 51. Furthermore, the identification information IDp and IDd is also stored in the non-volatile memory 71 by being obtained from the injectors 40 and 50 by the control device 70.

[0073] The determination unit 73 of the present embodiment carries out the processing which is described in Fig. 15 is shown, through. The processing, which is in Fig. As shown in Figure 15, this process is carried out for each orifice-flow injector 40 and each direct-injection injector 50. However, a simplified example case is described below in which the processing described in Figure 15 is carried out for each orifice-flow injector 40 and each direct-injection injector 50. Fig. Figure 15 shows how it is designed for the open-circuit injection injector 40.

[0074] As shown in Figure 15, the determination unit 73, as the processing of step S70, obtains the identification information IDp from the open-hole injection injector 40. Furthermore, the determination unit 73, as the processing of step S71, reads the identification information IDp of the open-hole injection injector 40, which is stored in the non-volatile memory 71.

[0075] During the processing of step S72, the destination unit 73 determines whether the identification information IDp obtained from the open-circuit injection injector 40 and the identification information IDp read from the non-volatile memory 71 match. If the identification information differs, the destination unit 73 determines that the open-circuit injection injector 40 has been replaced. In this case, during the processing of step S73, the destination unit 73 resets the cumulative number of operating operations NP of the open-circuit injection injector 40 to zero. Furthermore, during the processing of step S74, the destination unit 73 stores the identification information IDp obtained from the open-circuit injection injector 40 at that time in the non-volatile memory 71.Accordingly, the identification information IDp of the new open-circuit injection injector 40 is stored in the non-volatile memory 71 after replacement.

[0076] Furthermore, according to the fuel injection system 10 of the present embodiment described above, the effects and results shown below, (10), can be achieved.

[0077] (10) When injector 40, 50 is replaced, the cumulative number of operating operations NP, ND is automatically reset so that the cumulative number of operating operations NP and ND can be counted correctly. Other embodiments

[0078] Each embodiment can also be implemented in the following embodiments. - In the preceding embodiments, the internal combustion engine 20 contains two injectors: one open-circuit injection injector 40 and one direct injection injector 50. However, the number of injectors provided in the internal combustion engine 20 is not limited to two and can be three or more. Furthermore, the internal combustion engine 20 can contain either a plurality of open-circuit injection injectors or a plurality of direct injection injectors. - In the fuel injection system 10 in the previous embodiments, instead of the cumulative number of operating cycles NP and ND of the injectors 40 and 50, the change in stroke of each of the injectors 40 and 50, the change in injection quantity, the change in response behavior and the like can be used. - The internal combustion engine 20, for which the fuel injection system 10 is used in the previous embodiments, is not limited to a structure in which injectors 40 and 50 are attached to each cylinder 21. It can have a structure in which a common orifice injection injector is provided on an upstream section of the branch section of each cylinder 21 in the intake passage 22. - The fuel injection system 10 in the previous embodiments is used not only for an internal combustion engine 20 of the vehicle, but also for any engine, such as a fuel cell. The control device 70 and the control method therein, as described in the present disclosure, can be configured with one or more special computers, which are provided with at least one processor and at least one memory programmed to perform one or more functions designed as computer programs. The control device 70 and the control method described in the present disclosure can be configured with a special computer that is provided with at least one processor containing at least one special hardware logic circuit.The control device 70 and the control method thereof, described in the present disclosure, can be configured with at least one special computer, which is configured as a combination of (i) a processor and a memory programmed to implement one or more functions, and (ii) at least one processor provided with at least one hardware logic circuit. The computer program can be stored as instructions that can be executed by a computer on a tangible, non-volatile, computer-readable medium. The special hardware logic circuit and the hardware logic circuit can be configured as a digital circuit containing multiple logic circuits, or they can be configured as an analog circuit.

[0079] The present disclosure is not limited to the specific examples described above. Specific examples previously described, which have been suitably modified in their embodiment by a person skilled in the art, are also included within the scope of this disclosure, provided that the modified specific examples exhibit the characteristics of this disclosure. Each element contained in any of the specific examples previously described, as well as the arrangement, states, shape, and the like of the element, is not limited to that illustrated and may be suitably modified. The combinations of elements in any of the specific examples previously described may be suitably altered, provided that no technical contradiction arises.

Claims

[1] Fuel injection system comprising (i) a plurality of injectors, the plurality of injectors comprising at least two injectors (40, 50), the plurality of injectors being configured to inject gaseous fuel into an engine (20), (ii) a fuel tank (30) being configured to store gaseous fuel, and (iii) a delivery line (312, 313) being configured to supply gaseous fuel from the fuel tank to each of the plurality of injectors, the fuel injection system comprising: a wear amount estimation unit (72) configured to estimate a wear amount of each of the plurality of injectors; and a determination unit (73) configured to determine, based on the wear amount of each of the plurality of injectors estimated by the wear amount estimation unit, which of the plurality of injectors is preferably operated; and wherein the wear amount estimation unit is further configured to estimate the wear amount of each of the plurality of injectors based on a cumulative number of operating cycles of each of the plurality of injectors; and wherein The determining unit is further configured to calculate a subtraction value, obtained by subtracting the cumulative number of operating operations from a predetermined number of operating operations, for each of the plurality of injectors and preferably to operate one of the plurality of injectors that has the largest subtraction value. [2] Fuel injection system comprising (i) a plurality of injectors, the plurality of injectors comprising at least two injectors (40, 50), the plurality of injectors being configured to inject gaseous fuel into an engine (20), (ii) a fuel tank (30) being configured to store gaseous fuel, and (iii) a delivery line (312, 313) being configured to supply gaseous fuel from the fuel tank to each of the plurality of injectors, the fuel injection system comprising: a wear amount estimation unit (72) configured to estimate a wear amount of each of the plurality of injectors; and a determination unit (73) configured to determine, based on the wear amount of each of the plurality of injectors estimated by the wear amount estimation unit, which of the plurality of injectors is preferably operated; and wherein the wear amount estimation unit is further configured to estimate the wear amount of each of the plurality of injectors based on a cumulative number of operating cycles of each of the plurality of injectors; and wherein The determining unit is further configured to calculate a division value, obtained by dividing the cumulative number of operating operations by a predetermined number of operating operations, for each of the plurality of injectors and preferably to operate one of the plurality of injectors that has the smallest division value. [3] Fuel injection system comprising (i) a plurality of injectors, the plurality of injectors comprising at least two injectors (40, 50), the plurality of injectors being configured to inject gaseous fuel into an engine (20), (ii) a fuel tank (30) being configured to store gaseous fuel, and (iii) a delivery line (312, 313) being configured to supply gaseous fuel from the fuel tank to each of the plurality of injectors, the fuel injection system comprising: a wear amount estimation unit (72) configured to estimate a wear amount of each of the plurality of injectors; and a determination unit (73) configured to determine, based on the wear amount of each of the plurality of injectors estimated by the wear amount estimation unit, which of the plurality of injectors is preferably operated; and wherein The determination unit is further configured to perform the processing to determine one of the plurality of injectors, which is preferably operated, within a predetermined time interval. [4] Fuel injection system comprising (i) a plurality of injectors, the plurality of injectors comprising at least two injectors (40, 50), the plurality of injectors being configured to inject gaseous fuel into an engine (20), (ii) a fuel tank (30) being configured to store gaseous fuel, and (iii) a delivery line (312, 313) being configured to supply gaseous fuel from the fuel tank to each of the plurality of injectors, the fuel injection system comprising: a wear amount estimation unit (72) configured to estimate a wear amount of each of the plurality of injectors; and a determination unit (73) configured to determine, based on the wear amount of each of the plurality of injectors estimated by the wear amount estimation unit, which of the plurality of injectors is preferably operated; and wherein The determination unit is further configured to perform the processing to determine one of the plurality of injectors that is preferably operated at a time when the engine has been started or at a time after the engine has been stopped. [5] Fuel injection system comprising (i) a plurality of injectors, the plurality of injectors comprising at least two injectors (40, 50), the plurality of injectors being configured to inject gaseous fuel into an engine (20), (ii) a fuel tank (30) being configured to store gaseous fuel, and (iii) a delivery line (312, 313) being configured to supply gaseous fuel from the fuel tank to each of the plurality of injectors, the fuel injection system comprising: a wear amount estimation unit (72) configured to estimate a wear amount of each of the plurality of injectors; and a determination unit (73) configured to determine, based on the wear amount of each of the plurality of injectors estimated by the wear amount estimation unit, which of the plurality of injectors is preferably operated; and wherein The determination unit is further configured to perform the processing to determine one of the plurality of injectors that is preferably operated at a time when a vehicle is stopped. [6] Fuel injection system comprising (i) a plurality of injectors, the plurality of injectors comprising at least two injectors (40, 50), the plurality of injectors being configured to inject gaseous fuel into an engine (20), (ii) a fuel tank (30) being configured to store gaseous fuel, and (iii) a delivery line (312, 313) being configured to supply gaseous fuel from the fuel tank to each of the plurality of injectors, the fuel injection system comprising: a wear amount estimation unit (72) configured to estimate a wear amount of each of the plurality of injectors; and a determination unit (73) configured to determine, based on the wear amount of each of the plurality of injectors estimated by the wear amount estimation unit, which of the plurality of injectors is preferably operated; and wherein The determination unit is further configured to perform the processing to determine one of the plurality of injectors that is preferably operated at a time of a fuel cut-off control of the engine. [7] Fuel injection system comprising (i) a plurality of injectors, the plurality of injectors comprising at least two injectors (40, 50), the plurality of injectors being configured to inject gaseous fuel into an engine (20), (ii) a fuel tank (30) being configured to store gaseous fuel, and (iii) a delivery line (312, 313) being configured to supply gaseous fuel from the fuel tank to each of the plurality of injectors, the fuel injection system comprising: a wear amount estimation unit (72) configured to estimate a wear amount of each of the plurality of injectors; and a determination unit (73) configured to determine, based on the wear amount of each of the plurality of injectors estimated by the wear amount estimation unit, which of the plurality of injectors is preferably operated; and wherein the fuel injection system further comprises a warning unit (74) designed to issue a warning based on the fact that the cumulative number of operating operations of one of the plurality of injectors corresponds to a predetermined number of operating operations or more. [8] Fuel injection system comprising (i) a plurality of injectors, including at least two injectors (40, 50), wherein the plurality of injectors is configured to inject gaseous fuel into an engine (20), (ii) a fuel tank (30) configured to store gaseous fuel, and (iii) a delivery line (312, 313) configured to supply gaseous fuel from the fuel tank to each of the plurality of injectors, wherein the fuel injection system comprises: a wear amount estimation unit (72) configured to estimate a wear amount of each of the plurality of injectors; and a determination unit (73) configured to determine, based on the wear amount of each of the plurality of injectors estimated by the wear amount estimation unit, which of the plurality of injectors is preferably operated; and wherein, in cases where (i) the cumulative number of operating cycles of at least one of the plurality of injectors provided in a specific cylinder of the plurality of cylinders of the engine has reached a predetermined number of operating cycles, and (ii) the cumulative number of operating cycles of another of the plurality of injectors provided in the specific cylinder has not reached the predetermined number of operating cycles, The determining unit is further configured to preferably operate the other injector from the plurality of injectors whose cumulative number of operating operations has not reached the predetermined number of operating operations, and to prevent at least one injector from the plurality of injectors whose cumulative number of operating operations has reached the predetermined number of operating operations from being operated. [9] Fuel injection system according to any one of claims 1 to 8, wherein the engine is an internal combustion engine (20). [10] Fuel injection system according to claim 9, wherein each cylinder (21) of the internal combustion engine is provided with at least two injectors from the plurality of injectors. [11] Fuel injection system according to any one of claims 1 to 10, wherein the multitude of injectors is provided at a multitude of corresponding positions, with an identical arrangement being specified for each of the multitude of cylinders in the engine; the determination unit is further configured, a process for determining a first injector from the plurality of injectors in a specific cylinder from the plurality of cylinders, which is preferably operated, wherein the first injector is provided at a first corresponding position from the plurality of corresponding positions, which is defined in the identical arrangement in the specific cylinder, and preferably to operate a second injector from the plurality of injectors in each of the plurality of cylinders that is different from the specific cylinder, wherein the second injector is provided at the same first corresponding position in the identical arrangement in each of the plurality of cylinders that is different from the specific cylinder. [12] Fuel injection system according to any one of claims 1 to 11, wherein at least one of the plurality of injectors is a direct injection injector (50) configured to inject gaseous fuel directly into a cylinder of an engine. [13] Fuel injection system according to claim 12, wherein the determining unit is further configured to operate the direct injection injector regardless of the amount of wear when an engine load is greater than or equal to a predetermined value. [14] Fuel injection system according to any one of claims 1 to 10, wherein at least one of the plurality of injectors is an orifice injection injector (40) configured to inject gaseous fuel into an inlet passage of the engine. [15] Fuel injection system according to claim 14, further comprising a pressure sensor (60) configured to detect fuel pressure inside the fuel tank, wherein The determining unit is further configured to operate the orifice injection injector regardless of the amount of wear when the pressure inside the fuel tank is less than or equal to a predetermined value. [16] Fuel injection system according to any one of claims 1 to 15, wherein the determining unit is further configured to determine, based on identification information provided for the plurality of injectors, whether one of the plurality of injectors provided in the engine has been replaced or not. [17] Fuel injection system according to claim 16, wherein the determining unit is further configured to reset the cumulative number of operating cycles for the one from the plurality of injectors that has been determined to have been replaced when it is determined that one from the plurality of injectors provided in the engine has been replaced.

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