Fuel injection control device for internal combustion engines

Abstract

To suppress abrasion of a sheet equipped in an in-cylinder injection valve that injects gas fuel.SOLUTION: An internal combustion engine 10 comprises an in-cylinder injection valve 84 that injects gaseous fuel directly into a cylinder from an injection hole by moving a needle away from a seat, and a blow-by gas treatment device that recirculates blow-by gas from a crankcase 19 to an intake passage. A controller 100 performs a suction process that suctions gas in the cylinder into the injection hole of the in-cylinder injection valve 84 when the blow-by gas is being recirculated by the blow-by gas treatment device.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a fuel injection control device for an internal combustion engine.

Background Art

[0002] For example, Patent Document 1 discloses an injection valve that injects gaseous fuel. Gaseous fuel has lower lubricity compared to liquid fuel. Therefore, the injection valve described in Patent Document 1 is configured to provide a seal member with a low coefficient of friction between a needle, which is a sliding part, and a nozzle body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in an injection valve that injects gaseous fuel, a needle and a seat on which the needle seats come into contact without being lubricated. Therefore, there is a risk that the seat will wear out.

Means for Solving the Problems

[0005] The fuel injection control device for an internal combustion engine that solves the above problems is applied to an internal combustion engine including an in-cylinder injection valve that directly injects gaseous fuel into a cylinder by separating a needle from a seat, and a blow-by gas treatment device that recirculates blow-by gas from a crankcase to an intake passage. This fuel injection control device executes an intake process of inhaling the gas in the cylinder into the injection hole when the recirculation of blow-by gas by the blow-by gas treatment device is being performed.

Effects of the Invention

[0006] According to this invention, wear on the seat of an in-cylinder injection valve that injects gaseous fuel can be suppressed. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic diagram showing the configuration of an internal combustion engine in the first embodiment. [Figure 2] This flowchart shows the procedure for processing performed by the control device of the same embodiment. [Figure 3] This is a timing chart showing an example of the execution of the suction process in the same embodiment. [Figure 4] This flowchart shows the procedure for processing performed by the control device of the second embodiment. [Figure 5] This is a timing chart showing an example of a modification to the suction process in the first embodiment. [Modes for carrying out the invention]

[0008] (First Embodiment) The following describes a first embodiment of a fuel injection control device for an internal combustion engine. <Configuration of an internal combustion engine> As shown in Figure 1, the internal combustion engine 10 comprises a cylinder block 11, a cylinder head 12, a head cover 13, and an oil pan 14. Inside the cylinder block 11 is a cylinder 16 in which a piston 15 is arranged to reciprocate.

[0009] The cylinder head 12 is provided with an intake port 30 for introducing intake air into the combustion chamber 17 of the internal combustion engine 10, and an exhaust port 70 for discharging exhaust gas from the combustion chamber 17. An intake valve 81 is provided in the intake port 30. The drive system for this intake valve 81 is provided with an intake-side valve timing variable mechanism 85, which is a variable valve timing mechanism that changes the valve timing (opening and closing timing) of the intake valve 81. An exhaust valve 82 is provided in the exhaust port 70. The drive system for this exhaust valve 82 is provided with an exhaust-side valve timing variable mechanism 86, which is a variable valve timing mechanism that changes the valve timing (opening and closing timing) of the exhaust valve 82.

[0010] Furthermore, the cylinder head 12 is equipped with an in-cylinder injection valve 84 for directly injecting hydrogen gas as a gaseous fuel into the cylinder, and a spark plug (not shown). The in-cylinder injection valve 84 has a well-known structure and includes a nozzle for injecting gaseous fuel, a needle for opening and closing the nozzle, a seat on which the needle sits, an electromagnetic coil for driving the needle, and a spring for biasing the needle in the closing direction. In this in-cylinder injection valve 84, gaseous fuel is injected directly into the cylinder from the nozzle when the needle moves away from the seat. In this in-cylinder injection valve 84, the sum of the fuel pressure acting on the needle and the biasing force of the spring becomes the closing force that biases the needle in the closing direction. Also, the magnetic force of the electromagnetic coil generated when energized and the in-cylinder pressure, which is the pressure inside the cylinder, become the opening force that biases the needle in the opening direction. When the closing force becomes smaller than the opening force, the nozzle opens as the needle moves away from the seat.

[0011] Hydrogen gas is stored in tank 200. The hydrogen gas in tank 200 is supplied to the in-cylinder injection valve 84 after its pressure is adjusted by the pressure reducing valve 210. The pressure reducing valve 210 is a pressure adjustment mechanism that adjusts the fuel pressure, which is the pressure of the gaseous fuel supplied to the in-cylinder injection valve 84. The pressure reducing valve 210 is an electromagnetic valve that adjusts the fuel pressure, which is the pressure of the hydrogen gas supplied to the in-cylinder injection valve 84, to a target fuel pressure Pt according to the engine operating conditions.

[0012] A crankcase 19 is provided at the bottom of the cylinder block 11, which houses the crankshaft 18, the output shaft of the internal combustion engine 10. An oil pan 14 for storing lubricating oil is provided at the bottom of the crankcase 19.

[0013] An intake manifold 29 equipped with a surge tank 60 is connected upstream of the intake port 30, and an intake pipe 20 is connected upstream of the surge tank 60. The intake pipe 20, surge tank 60, and intake manifold 29 constitute the intake passage of the internal combustion engine 10.

[0014] The intake manifold 20 is equipped with, in order from upstream, an air cleaner 21, an air flow meter 51, a compressor wheel 24C for a supercharger 24 driven by exhaust gases from the combustion chamber 17, an intercooler 27, a boost pressure sensor 54, and a throttle valve 28. An intake pressure sensor 55 is also installed in the surge tank 60. The throttle valve 28's opening angle is changed by an electric motor.

[0015] The air cleaner 21 filters the intake air taken into the intake manifold 20. The supercharger 24 supercharges the air in the intake manifold 20. The intercooler 27 cools the air after it has passed through the compressor wheel 24C. The throttle valve 28 adjusts the amount of intake air by adjusting the valve opening.

[0016] The air flow meter 51 detects the intake air volume GA. The boost pressure sensor 54 detects the boost pressure PTC, which is the pressure in the downstream portion of the compressor wheel 24C in the intake manifold 20. The intake pressure sensor 55 detects the intake pressure PIM, which is the pressure inside the surge tank 60.

[0017] Downstream of the exhaust port 70, an exhaust passage 90 is connected. In the middle of the exhaust passage 90, a housing for accommodating the turbine wheel 24T of the supercharger 24 is connected. Also, in the exhaust passage 90, the upstream part of the turbine wheel 24T and the downstream part of the same turbine wheel 24T are communicated via a bypass passage 92. In the middle of the bypass passage 92, a wastegate valve (hereinafter referred to as WGV) 93 whose opening degree is adjusted by an actuator is provided. This WGV 93 is a valve that adjusts the amount of exhaust flowing through the bypass passage 92. The larger its opening degree, the larger the amount of exhaust that bypasses the turbine wheel 24T and passes through the bypass passage 92. Therefore, the supercharging pressure of the intake air increased by the supercharger 24 becomes lower.

[0018] The internal combustion engine 10 is provided with a blow-by gas treatment device for treating gas that has leaked from the combustion chamber 17 into the crankcase 19 during the compression stroke or the combustion stroke, so-called blow-by gas. This blow-by gas treatment device is a device that returns blow-by gas from the crankcase 19 to the intake passage. The blow-by gas treatment device includes a suction passage 32 for guiding the blow-by gas in the crankcase 19 into the head cover 13. One end of the suction passage 32 opens into the head cover 13. Also, the other end of the suction passage 32 opens into the crankcase 19. Note that an oil separator (not shown) is provided in the suction passage 32.

[0019] The inside of the head cover 13 is connected to the surge tank 60 via a PCV valve 34 and a PCV passage 35. The PCV valve 34 opens when the pressure in the surge tank 60 becomes lower than the pressure in the head cover 13, that is, the pressure in the crankcase 19, and allows the inflow of blow-by gas from the head cover 13 into the surge tank 60. These suction passage 32, PCV valve 34, and PCV passage 35 constitute a communication passage that communicates the surge tank 60, which forms a part of the intake passage, and the crankcase 19.

[0020] When the pressure in the surge tank 60 is lower than the pressure in the crankcase 19, the PCV valve 34 opens. Therefore, the blow-by gas in the crankcase 19 is sucked into the surge tank 60 through the intake passage 32, the PCV valve 34, and the PCV passage 35. The sucked blow-by gas is sent into the cylinder together with the intake air and burned.

[0021] The blow-by gas treatment device also includes an air introduction passage 37 for introducing intake air into the crankcase 19 for scavenging. One end of both ends of the air introduction passage 37 is connected to the intake pipe 20 between the air cleaner 21 and the compressor wheel 24C. The air introduction passage 37 passes through the head cover 13, through the inside of the cylinder head 12 and the cylinder block 11, and is connected to the crankcase 19. An air-side separator 38, which is an oil separator installed in the head cover 13, is provided in the middle of the air introduction passage 37.

[0022] The control device 100 controls the internal combustion engine 10 and operates various operation target devices such as the throttle valve 28, the in-cylinder injection valve 84, the ignition plug, the intake-side valve timing variable mechanism 85, the exhaust-side valve timing variable mechanism 86, the WGV 93, and the pressure reducing valve 210.

[0023] The control device 100 includes a CPU 110 which is a central processing unit, a memory 120 in which control programs and data are stored, and the like. Then, the CPU 110 executes the programs stored in the memory 120 to execute processes related to various controls.

[0024] The control device 100 also receives detection signals from sensors other than those described above. For example, the control device 100 receives the detection signal from the crank angle sensor 52, which detects the rotation angle (crank angle) of the crankshaft 18 in order to calculate the engine rotation speed NE. The control device 100 also receives detection signals from the accelerator pedal operation amount sensor 53, which detects the accelerator pedal operation amount ACCP, and the vehicle speed sensor 56, which detects the vehicle speed SP of the vehicle equipped with the internal combustion engine 10. The control device 100 also receives the detection signal from the fuel pressure sensor 57, which detects the fuel pressure P of the hydrogen gas supplied to the in-cylinder injection valve 84.

[0025] The control device 100 calculates the engine load ratio KL based on the engine rotational speed NE and the intake air volume GA. The engine load ratio KL represents the ratio of the current cylinder inflow air volume to the cylinder inflow air volume when the internal combustion engine 10 is operating steadily under full load. The cylinder inflow air volume is the amount of air that flows into each cylinder during the intake stroke.

[0026] <Regarding inhalation treatment> When blow-by gas is being recirculated by the blow-by gas treatment device, the control device 100 performs an intake process to draw gas from inside the cylinder into the injection port of the in-cylinder injection valve 84.

[0027] Figure 2 shows the procedure for performing the suction process. The series of processes shown in Figure 2 are carried out by the CPU 110 executing a program stored in the memory 120 of the control device 100 at predetermined intervals. In the following, step numbers are represented by numbers preceded by "S".

[0028] When this process is started, the control device 100 determines whether the intake flag F is "ON" or not (S100). The intake flag F is a flag that is set to "ON" for every specified mileage, for example. If the intake process described later is performed for a specified time or longer, or if it is determined to be negative in either process S120 or S130 described later, the intake flag F is set to "OFF".

[0029] If the control device 100 determines that the intake flag F is "ON", it reads the engine rotation speed NE and the engine load ratio KL (S110). Next, the control device 100 determines whether the PCV flow rate Qp is equal to or greater than the threshold Qpref (S120). The PCV flow rate Qp is the flow rate of blow-by gas passing through the PCV valve 34. Since the PCV flow rate Qp is a value that correlates with the engine rotation speed NE and the engine load ratio KL, the control device 100 calculates the PCV flow rate Qp based on the engine rotation speed NE and the engine load ratio KL.

[0030] The threshold Qpref is a suitable value as follows: If the PCV flow rate Qp is low, the amount of oil component in the blow-by gas contained in the gas inside the cylinder will be low, which may prevent sufficient lubrication of the in-cylinder injection valve 84 seat using the oil component in the blow-by gas. Therefore, the threshold Qpref is pre-set to the lower limit of the PCV flow rate Qp required to lubricate such seats. In this embodiment, the process of S120 is a process to determine whether or not blow-by gas recirculation is being performed by the blow-by gas treatment device. When the PCV flow rate Qp is equal to or greater than the threshold Qpref, it is determined that blow-by gas recirculation is being performed by the blow-by gas treatment device.

[0031] If the control device 100 determines that the PCV flow rate Qp is equal to or greater than the threshold Qpref, it determines whether the engine rotational speed NE is equal to or greater than the threshold NEref (S130). The threshold NEref is a suitable value as follows: If the engine rotational speed NE is low, the in-cylinder pressure is low, and there is a risk that the intake process, which draws gas from inside the cylinder into the injection holes of the in-cylinder injection valve 84, may not be able to be performed sufficiently. Therefore, the threshold NEref is set to a lower limit value of the engine rotational speed NE required to perform such intake processing.

[0032] The control device 100 executes the intake process (S140) if it determines that the engine rotational speed NE is greater than or equal to the threshold NEref. As part of the intake process, the control device 100 opens and closes the in-cylinder injection valve 84 during the compression stroke, after a specified period has elapsed since the completion of fuel injection to obtain engine output. The injection time when opening and closing the in-cylinder injection valve 84 can be set to, for example, the minimum injection time achievable by the in-cylinder injection valve 84. Hereinafter, the opening and closing operation of the in-cylinder injection valve 84 performed to execute the intake process will be referred to as minute injection.

[0033] Figure 3 shows an example of a minute fuel injection. In the example shown in Figure 3, fuel injection to obtain engine power is performed during the compression stroke, but it may also be performed during other strokes, such as the intake stroke.

[0034] As shown in Figure 3, fuel injection to obtain engine power is started at crank angle CA1 in the first half of the compression stroke. Then, fuel injection to obtain engine power is terminated at crank angle CA2. Then, at crank angle CA3 during the compression stroke, after a specified period Ta has elapsed from crank angle CA2, the in-cylinder injection valve 84 is opened, and minute injection is started. Then, at crank angle CA4 during the compression stroke, the in-cylinder injection valve 84 is closed, and minute injection is terminated.

[0035] The amount of gas drawn into the nozzle of the in-cylinder injection valve 84 increases with higher in-cylinder pressure. Here, the in-cylinder pressure changes depending on the timing during the compression stroke and the engine rotation speed NE. Therefore, the control device 100 variably sets the opening timing of the in-cylinder injection valve 84 when performing a minute injection according to the engine rotation speed NE, so that the amount of gas drawn into the nozzle of the cylinder is an appropriate amount. In other words, the above period Ta is variably set according to the engine rotation speed NE. For simplicity, the opening timing of the in-cylinder injection valve 84 when performing a minute injection may be set to a fixed value.

[0036] Once the control device 100 has completed the process described in S140 above, it will terminate this process. Furthermore, if the control device 100 determines that any of the processes S100, S120, or S130 is negative, it stops the suction process (150) and terminates this process.

[0037] <Mechanism and Effects> The operation and effects of this embodiment will now be described. (1-1) The control device 100 performs an intake process to draw gas from inside the cylinder into the nozzle of the in-cylinder injection valve 84 when blow-by gas is being recirculated by the blow-by gas treatment device. By performing this intake process, blow-by gas contained in the gas inside the cylinder is drawn into the nozzle of the in-cylinder injection valve 84. Since blow-by gas contains oil components, the seat of the in-cylinder injection valve 84 is lubricated by these oil components. Therefore, wear on the seat of the in-cylinder injection valve 84 that injects gaseous fuel can be suppressed.

[0038] (1-2) As described above, the intake process is performed to open and close the in-cylinder injection valve 84 during the compression stroke after a specified period Ta has elapsed since the fuel injection required to obtain engine output was completed. When this intake process is performed, immediately after the in-cylinder injection valve 84, which was open, is closed, the gaseous fuel in the nozzle flows out into the cylinder due to inertia. Immediately after the gaseous fuel flows out of the nozzle in this way, the pressure inside the nozzle temporarily decreases. As a result, gases inside the cylinder that are present around the opening of the nozzle that opens into the cylinder are drawn into the nozzle.

[0039] Furthermore, the opening and closing of the in-cylinder injection valve 84 during the compression stroke, when the pressure inside the cylinder is high, promotes the intake of gas into the injection hole. Furthermore, immediately after fuel injection to obtain engine output, the amount of gaseous fuel present around the nozzle opening increases, while the amount of gas in the cylinder, including blow-by gas, decreases. The amount of gaseous fuel present around the nozzle opening decreases with time elapsed since the end of injection. On the other hand, the amount of gas in the cylinder, including blow-by gas, present around the nozzle opening increases as the amount of gaseous fuel decreases. Therefore, in this embodiment, a small amount of fuel is injected to open and close the in-cylinder injection valve 84 after a specified period Ta has elapsed since the end of fuel injection to obtain engine output. As a result, it is possible to suppress the intake of gaseous fuel into the nozzle while promoting the intake of gas in the cylinder, including blow-by gas.

[0040] (Second Embodiment) Next, a second embodiment of the fuel injection control device for an internal combustion engine will be described. In this embodiment, a different intake process is performed compared to the first embodiment. The intake process of this embodiment will be described below, focusing on the differences from the first embodiment.

[0041] <Regarding inhalation treatment> Figure 4 shows the procedure for performing the suction process in this embodiment. In each process shown in Figure 4, the same step numbers are used for processes that are the same as those shown in Figure 2.

[0042] When this process is started, the control device 100 determines whether the intake flag F is "ON" or not (S100). The intake flag F is a flag that is set to "ON" for every specified mileage, for example. If the intake process described later is performed for a specified time or longer, or if it is determined to be negative in either process S120 or S200 described later, the intake flag F is set to "OFF".

[0043] If the control device 100 determines that the intake flag F is "ON", it reads the engine rotation speed NE and the engine load ratio KL (S110). Next, the control device 100 determines whether the PCV flow rate Qp is equal to or greater than the threshold Qpref (S120). The PCV flow rate Qp and the threshold Qpref are the same values ​​as those described in the first embodiment.

[0044] If the control device 100 determines that the PCV flow rate Qp is greater than or equal to the threshold Qpref, it determines whether the torque Tq generated from the internal combustion engine 10 is less than or equal to the threshold Tqref (S200). Since the torque Tq is a value correlated with the engine load ratio KL, the control device 100 calculates the torque Tq based on the engine load ratio KL.

[0045] The threshold value Tqref is a suitable value as follows: When the torque Tq is large, the combustion temperature of the fuel-air mixture is high, and if the gas in the cylinder is drawn into the nozzle of the in-cylinder injection valve 84, the in-cylinder injection valve 84 may be damaged. Therefore, the threshold value Tqref is pre-set to an upper limit of torque Tq that can suppress such damage to the in-cylinder injection valve 84.

[0046] If the control device 100 determines that the torque Tq is below the threshold Tqref, it executes the intake process (S210). As the intake process, the control device 100 executes a fuel pressure reduction process, which controls the pressure reducing valve 210 to reduce the fuel pressure P. In this fuel pressure reduction process, the target fuel pressure Pt calculated according to the engine operating state is used as the base value, and the value obtained by subtracting the pressure reduction amount Pd from that base value is set as the new target fuel pressure Pt. The control device 100 then controls the pressure reducing valve 210 to obtain the set target fuel pressure Pt. Here, the higher the maximum in-cylinder pressure Pmax, which is the maximum value of the in-cylinder pressure, the greater the amount of gas in the cylinder that is drawn into the nozzle of the in-cylinder injection valve 84 through the execution of the intake process. If the amount of gas drawn in increases excessively in this way, the in-cylinder injection valve 84 may be damaged. For this reason, the control device 100 variably sets the pressure reduction amount Pd so that the pressure reduction amount Pd becomes smaller when the maximum in-cylinder pressure Pmax is high. By setting the pressure drop Pd in ​​this variable manner, the reduction in the valve closing force described above is suppressed as the maximum in-cylinder pressure Pmax is higher, thereby preventing an excessive increase in the amount of gas drawn into the cylinder through the injection nozzle. The maximum in-cylinder pressure Pmax is calculated by the control device 100 based on the engine load ratio KL and engine rotational speed NE, etc. Incidentally, for simplicity, the pressure drop Pd may be set to a fixed value. Alternatively, the target fuel pressure Pt when performing the intake process may be set directly based on the maximum in-cylinder pressure Pmax.

[0047] Once the control device 100 has completed the process described in S210 above, it terminates this process. Furthermore, if the control device 100 determines that any of the processes S100, S120, or S200 is negative, it stops the suction process (220) and terminates this process.

[0048] <Mechanism and Effects> The operation and effects of this embodiment will now be described. (2-1) The control device 100 performs an intake process to draw gas from inside the cylinder into the nozzle of the in-cylinder injection valve 84 when blow-by gas is being recirculated by the blow-by gas treatment device. By performing this intake process, blow-by gas contained in the gas inside the cylinder is drawn into the nozzle of the in-cylinder injection valve 84. Since blow-by gas contains oil components, the seat of the in-cylinder injection valve 84 is lubricated by these oil components. Therefore, wear on the seat of the in-cylinder injection valve 84 that injects gaseous fuel can be suppressed.

[0049] (2-2) As an intake process as described above, a fuel pressure reduction process is implemented in which the pressure reducing valve 210 is controlled to lower the fuel pressure P compared to when the intake process is not performed. When this intake process is performed, the pressure of the gaseous fuel supplied to the in-cylinder injector 84 is reduced, so that the pressure inside the cylinder causes the needle of the in-cylinder injector 84 to move away from the seat. As the needle moves away from the seat in this way, it becomes possible to draw gas from inside the cylinder into the nozzle of the in-cylinder injector 84.

[0050] <Example of changes> Furthermore, each of the above embodiments may be implemented with the following modifications. The above embodiments and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0051] In the intake process of S140 described in the first embodiment, a minute amount of fuel injection is performed during the compression stroke, but other intake processes may be performed. For example, fuel injection from the in-cylinder injection valve 84 may be performed during the compression stroke, and the intake process may be a process that retards the timing of the end of fuel injection compared to when the intake process is not performed.

[0052] Even with these modifications, immediately after closing the in-cylinder injection valve 84, which was previously open, the gaseous fuel in the nozzle flows out into the cylinder due to inertia. Immediately after the gaseous fuel flows out of the nozzle in this way, the pressure inside the nozzle temporarily decreases. As a result, gas from inside the cylinder that is present around the opening of the nozzle that opens into the cylinder is drawn into the nozzle. Furthermore, by performing fuel injection from the in-cylinder injection valve 84 during the compression stroke, when the pressure inside the cylinder is high, and opening and closing the in-cylinder injection valve 84, the intake of gas into the nozzle is promoted. In this modification, the timing of the end of fuel injection performed during the compression stroke is retarded as part of the intake process. Therefore, compared to when the intake process is not performed, the in-cylinder pressure is higher when the fuel injection ends, which promotes the intake of gas from inside the cylinder into the nozzle.

[0053] Figure 5 shows the change in fuel injection timing in this modification example. In Figure 5, the fuel injection performed between crank angles CA1 and CA2 during the compression stroke is the fuel injection timing when fuel injection is performed to obtain engine output and intake processing is not carried out. On the other hand, in Figure 5, the fuel injection performed between crank angles CA5 and CA6 during the compression stroke is the fuel injection timing when fuel injection is performed to obtain engine output and intake processing is carried out.

[0054] As shown in Figure 5, when the intake process is performed, the control device 100 retards the entire fuel injection period so that the end of fuel injection is retarded to a crank angle CA6, which is later than the crank angle CA2. The amount of retardation of the end of fuel injection at this time may be fixed in simple terms, but it may also be set to a variable value, for example as follows. That is, as described above, the amount of gas in the cylinder that is drawn into the nozzle of the in-cylinder injection valve 84 increases when the in-cylinder pressure is high. The in-cylinder pressure changes depending on the timing during the compression stroke and the engine rotation speed NE. Therefore, the control device 100 may set the amount of retardation of the end of fuel injection to a variable value according to the engine rotation speed NE so that the amount of gas in the cylinder drawn into the nozzle is an appropriate amount. Note that when the end of fuel injection is retarded during the compression stroke, the atomization state of the fuel and the amount of fuel adhering to the piston may change compared to when the timing is not retarded. For this reason, the fuel injection period when the intake process is performed and the fuel injection period before the intake process are performed may be made different.

[0055] In the first embodiment, the process in S130 may be omitted. In the second embodiment, the process in S200 may be omitted. • The gaseous fuel used was hydrogen gas, but other gaseous fuels, such as compressed natural gas, may also be used.

[0056] It is not essential that the internal combustion engine 10 is equipped with an intake valve timing variable mechanism 85 or an exhaust valve timing variable mechanism 86. It is not mandatory for the internal combustion engine 10 to be equipped with a supercharger 24.

[0057] The control device 100 includes a CPU 110 and a memory 120, and executes software processing. However, this is merely an example. The control device 100 may also include, for example, a dedicated hardware circuit (e.g., an ASIC) that processes at least a portion of the software processing performed in the above embodiment. That is, the control device 100 may have any of the following configurations (a) to (c): (a) It includes a processing unit that executes all of the above processing according to a program, and a program storage device such as a memory that stores the program. (b) It includes a processing unit and a program storage device that execute a portion of the above processing according to a program, and a dedicated hardware circuit that executes the remaining processing. (c) It includes a dedicated hardware circuit that executes all of the above processing. Here, there may be multiple software circuits with processing units and program storage devices, and multiple dedicated hardware circuits. That is, the above processing may be executed by a processing circuit that includes at least one of one or more software circuits and one or more dedicated hardware circuits. The program storage device, i.e., computer-readable media, includes any available media that can be accessed by a general-purpose or dedicated computer. [Explanation of symbols]

[0058] 10... Internal combustion engine 14… Oil pan 19... Crankcase 20... Intake pipe 24… Supercharger 28… Throttle valve 29…Intake manifold 30…Intake port 32...Suction path 34…PCV valve 35…PCV passage 37... Atmospheric Intake 38... Atmospheric separator 60... Surge Tank 70... Exhaust port 81…Intake valve 82... Exhaust valve 84...In-cylinder injection valve 90... Exhaust passage 92... Bypass passage 100...Control device 110...CPU 120...memory 200... tank 210... Pressure Reducing Valve

Claims

1. A fuel injection control device applicable to an internal combustion engine comprising an in-cylinder injection valve that injects gaseous fuel directly into the cylinder from an injection hole by separating the needle from the seat, and a blow-by gas treatment device that recirculates blow-by gas from the crankcase to the intake passage, When the blow-by gas is being recirculated by the blow-by gas treatment device, an intake process is performed to draw the gas from the cylinder into the injection hole. The aforementioned intake process is a process in which the in-cylinder injection valve is opened and closed during the compression stroke, after a specified period has elapsed since the completion of fuel injection to obtain engine output. Fuel injection control device for internal combustion engines.

2. A fuel injection control device applicable to an internal combustion engine comprising an in-cylinder injection valve that injects gaseous fuel directly into the cylinder from an injection hole by separating the needle from the seat, and a blow-by gas treatment device that recirculates blow-by gas from the crankcase to the intake passage, When the blow-by gas is being recirculated by the blow-by gas treatment device, an intake process is performed to draw the gas from the cylinder into the injection hole. Fuel injection from the in-cylinder injection valve is performed during the compression stroke, The aforementioned intake process is a process that delays the timing of fuel injection termination compared to when the intake process is not performed. Fuel injection control device for internal combustion engines.

3. A fuel injection control device applicable to an internal combustion engine comprising: an in-cylinder injection valve that injects gaseous fuel directly into the cylinder from an injection hole by separating a needle from a seat; a pressure adjustment mechanism that adjusts the pressure of the gaseous fuel supplied to the in-cylinder injection valve; and a blow-by gas treatment device that recirculates blow-by gas from the crankcase to the intake passage, wherein When the blow-by gas is being recirculated by the blow-by gas treatment device, an intake process is performed to draw the gas from the cylinder into the injection hole. The aforementioned suction process is a process of controlling the pressure adjustment mechanism so that the pressure is lower compared to when the suction process is not performed. Fuel injection control device for internal combustion engines.

Images