internal combustion engine

Abstract

The objective of this invention is to suppress the increase of hydrogen concentration in the crankcase while suppressing the impact on the output control of an internal combustion engine. An internal combustion engine using hydrogen as fuel includes: an ignition device that ignites gases in the crankcase; a control device that controls the ignition performed by the ignition device; and a hydrogen concentration sensor that detects the hydrogen concentration in the crankcase. When the range of hydrogen concentration in the crankcase suitable for slow combustion is defined as a slow combustion range, the control device performs ignition processing performed by the ignition device when the hydrogen concentration detected by the hydrogen concentration sensor is within the slow combustion range.

Description

Technical Field

[0001] This invention relates to a control device for an internal combustion engine. Background Technology

[0002] In hydrogen-fueled internal combustion engines, the hydrogen concentration in the crankcase can be high because the blow-by gas flowing into the crankcase contains hydrogen.

[0003] Therefore, in the internal combustion engine described, for example, in Patent Document 1, air is introduced into the crankcase from downstream of the compressor impeller of the turbocharger to dilute the gas in the crankcase. Furthermore, the diluted gas is discharged into the intake passage, which is located upstream of the compressor impeller.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2024-117362 Summary of the Invention

[0005] In the internal combustion engine described in the aforementioned Patent Document 1, since a dilution gas containing hydrogen is discharged into the intake passage, it may affect the output control of the internal combustion engine.

[0006] An internal combustion engine that solves the above-mentioned problems uses hydrogen as fuel, and the internal combustion engine includes: an ignition device that ignites gas in the crankcase; and a control device that controls the ignition performed by the ignition device.

[0007] Invention Effects

[0008] According to the present invention, it is possible to suppress the increase of hydrogen concentration in the crankcase while suppressing the influence on the output control of the internal combustion engine. Attached Figure Description

[0009] Figure 1 This is a schematic diagram showing the structure of an internal combustion engine in one embodiment.

[0010] Figure 2 This is a flowchart illustrating the steps of the processing performed by the control device in this embodiment. Detailed Implementation

[0011] The following describes one embodiment of an internal combustion engine.

[0012] <Structure of an Internal Combustion Engine>

[0013] like Figure 1 As shown, the internal combustion engine 10 includes a cylinder block 11, a cylinder head 12, and a cylinder head cover 13. A cylinder 16 is disposed within the cylinder block 11 and configured to allow the piston 15 to reciprocate.

[0014] 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 or an exhaust port 70 for discharging exhaust gas from the combustion chamber 17. An intake valve 81 is provided on the intake port 30. An exhaust valve 82 is provided on the exhaust port 70.

[0015] A fuel injection valve 84 and a spark plug 23 are provided on the cylinder head 12 to inject hydrogen, which serves as fuel for the internal combustion engine 10, into the combustion chamber 17.

[0016] A crankcase 19 is provided at the lower part of the cylinder block 11 to accommodate the crankshaft 18 of the internal combustion engine 10.

[0017] An ignition device 200 for igniting the gas inside the crankcase 19 is provided on the crankcase 19. In this embodiment, the ignition device 200 is a spark plug that performs spark discharge.

[0018] An intake manifold 29 with a pressure regulating chamber 60 is connected upstream of the intake port 30, and an intake pipe 20 is connected upstream of the pressure regulating chamber 60. An intake pressure sensor 53 for detecting the intake pressure PIM is installed on the pressure regulating chamber 60. The intake pressure PIM is the pressure inside the pressure regulating chamber 60 and is the pressure downstream of the throttle valve 28 in the intake passage.

[0019] The intake pipe 20, the pressure regulating chamber 60, and the intake manifold 29 constitute the intake passage of the internal combustion engine 10.

[0020] In the intake manifold 20, from upstream, there are an air filter 21, an air flow meter 51, a compressor impeller 24C of a turbocharger 24 driven by exhaust gas from the combustion chamber 17, a boost pressure sensor 52, an intercooler 27, and a throttle valve 28.

[0021] Air filter 21 filters the intake air entering the intake manifold 20. Air flow meter 51 detects the intake air volume GA of the internal combustion engine 10. Compressor impeller 24C of turbocharger 24 pressurizes the intake air flowing in the intake passage. Boost pressure sensor 52 detects the boost pressure PTC, which is the pressure downstream of compressor impeller 24C in intake manifold 20. Intercooler 27 cools the air after passing through compressor impeller 24C. Throttle valve 28 is a valve that regulates the intake air volume of internal combustion engine 10, and the valve opening is changed by an electric motor.

[0022] An exhaust passage 90 is connected downstream of the exhaust port 70. A housing for accommodating the turbine impeller 24T of the turbocharger 24 is connected midway through the exhaust passage 90.

[0023] The internal combustion engine 10 is equipped with a blow-by gas treatment mechanism to treat blow-by gas that leaks from the combustion chamber 17 into the crankcase 19. This blow-by gas contains hydrogen as fuel, lubricating oil of the internal combustion engine 10, combustion gases of the air-fuel mixture, etc.

[0024] The blow-by mechanism includes a first connecting passage 37. One end of the first connecting passage 37 is connected to the intake pipe 20 between the air filter 21 and the compressor impeller 24C. The first connecting passage 37 passes through the cylinder head cover 13, through the interior of the cylinder head 12 and the cylinder block 11, and connects to the crankcase 19. A separator 38, which serves as an oil separator housed within the cylinder head cover 13, is provided midway through the first connecting passage 37. The first connecting passage 37 and the separator 38 constitute the first passage connecting the portion of the intake passage upstream of the compressor impeller 24C to the crankcase 19.

[0025] The blow-by gas treatment mechanism includes a second communication passage 32 for guiding blow-by gas in the crankcase 19 to a separator 31, which is an oil separator located within the cylinder head cover 13. The end of the second communication passage 32, which is connected to the separator 31, opens into the crankcase 19. Alternatively, the separator 31 may be installed midway through the second communication passage 32.

[0026] The separator 31 is connected to the pressure regulating chamber 60 via a positive crankcase ventilation (PCV) valve 34, which acts as a differential pressure valve, and a PCV passage 35. When the pressure in the pressure regulating chamber 60 is lower than the pressure in the separator 31, the PCV valve 34 opens, allowing blow-by gas to flow from the separator 31 into the pressure regulating chamber 60. The pressure in the separator 31 is equal to the pressure in the crankcase 19. Therefore, the PCV valve 34 is the valve that opens when the intake pressure PIM is lower than the pressure in the crankcase 19.

[0027] The second connecting passage 32, separator 31, PCV valve 34 and PCV passage 35 constitute the part of the intake passage that is downstream of throttle valve 28 and the second passage of crankcase 19.

[0028] When the internal combustion engine 10 is operating in the naturally aspirated region and the intake pressure PIM is lower than atmospheric pressure, the pressure in the pressure regulating chamber 60 is lower than the pressure in the crankcase 19. Therefore, the PCV valve 34 opens. When the PCV valve 34 is open, fresh air flows into the crankcase 19 from the intake manifold 20 via the first connecting passage 37. Furthermore, blow-by gas in the crankcase 19 is drawn into the pressure regulating chamber 60 via the second connecting passage 32, the separator 31, the PCV valve 34, and the PCV passage 35. The blow-by gas drawn into the pressure regulating chamber 60 is sent to the combustion chamber 17 for combustion along with the intake air. In the naturally aspirated region, by handling the blow-by gas in this way, the hydrogen in the crankcase 19 is replaced, thus reducing the hydrogen concentration in the crankcase 19.

[0029] The control device 100 takes the internal combustion engine 10 as the controlled object and operates various operating objects such as the throttle valve 28, fuel injection valve 84, spark plug 23, and ignition device 200.

[0030] The control device 100 includes a CPU 110 for performing calculations and a memory 120 for storing control programs or data. Furthermore, the control device 100 performs various control-related processes by executing the programs stored in the memory 120 through the CPU 110.

[0031] The control unit 100 receives detection signals from the air flow meter 51, boost pressure sensor 52, and intake pressure sensor 53. It also receives detection signals from various other sensors. For example, the control unit 100 receives a detection signal from the crankshaft angle sensor 54, which detects the crankshaft rotation angle (crankshaft angle) of the crankshaft 18 to calculate the internal combustion engine speed NE. It also receives a detection signal from the throttle operation amount sensor 55, which detects the throttle operation amount (ACCP) of the throttle pedal, which regulates the output of the internal combustion engine 10. Furthermore, the control unit 100 receives a detection signal from the throttle valve sensor 56, which detects the throttle valve opening (TA), which determines the opening degree of the throttle valve 28. Finally, the control unit 100 receives a detection signal from the vehicle speed sensor 57, which detects the vehicle speed (SP). Finally, the control unit 100 receives a detection signal from the hydrogen concentration sensor 58, which detects the hydrogen concentration (H) within the crankcase 19.

[0032] The control device 100 calculates the internal combustion engine load rate KL based on the internal combustion engine speed NE and the intake air volume GA. The internal combustion engine load rate KL is a parameter that determines the amount of air filled into the combustion chamber 17, and is the ratio of the inflow air volume for a single cylinder and a single combustion cycle to the reference inflow air volume. The reference inflow air volume can be set variably according to the internal combustion engine speed NE.

[0033] <Regarding Ignition Process>

[0034] When the internal combustion engine 10 is operating in the boosted region where the turbocharger 24 provides boost, the pressure inside the crankcase 19 is likely to be higher than the pressure inside the intake manifold 20 between the air filter 21 and the compressor impeller 24C. Therefore, the inflow of fresh air from the intake manifold 20 via the first connecting passage 37 into the crankcase 19 becomes difficult. Consequently, the hydrogen concentration inside the crankcase 19 tends to increase.

[0035] Therefore, the control device 100 suppresses such an adverse situation by performing the ignition process described below.

[0036] exist Figure 2 The steps for performing the ignition process are shown in the diagram. Figure 2The processing shown is achieved by the CPU 110 repeatedly executing the program stored in the memory 120 of the control device 100 at predetermined cycles. Furthermore, the step numbers of each process will be indicated below by numbers beginning with "S".

[0037] If start Figure 2 The process shown in the diagram allows the control device 100 to acquire the currently detected hydrogen concentration H (S100).

[0038] Next, the control device 100 determines whether the acquired hydrogen concentration H is within the slow combustion range (S110). The slow combustion range is the range of hydrogen concentrations in the crankcase 19 that ignite but burn slowly without pressure increase, and is determined in advance. For example, a range of about 4 vol% or more, which is about 8 vol% or less and is the lower limit of the flammability limit concentration of hydrogen, can be cited as such a slow combustion range.

[0039] If it is determined that the obtained hydrogen concentration H is within the slow combustion range (S110: Yes), the control device 100 operates the ignition device 200 to perform ignition (S120).

[0040] Furthermore, if the process of S120 is executed or if the result of the process of S110 is determined to be negative, the control device 100 terminates the execution of this process in the current execution cycle.

[0041] <Function and Effects of This Implementation Method>

[0042] (1) The internal combustion engine 10 using hydrogen as fuel includes: an ignition device 200 for igniting gas in the crankcase 19; and a control device 100 for controlling the ignition performed by the ignition device 200. Therefore, the blow-by gas in the crankcase 19 containing hydrogen can be combusted by ignition performed by the ignition device 200 before the hydrogen concentration in the crankcase 19 becomes high. Therefore, the increase of hydrogen concentration in the crankcase 19 can be suppressed while suppressing the influence on the output control of the internal combustion engine 10.

[0043] (2) The range of hydrogen concentrations that allows for slow combustion without pressure rise is called the slow combustion range. Therefore, the internal combustion engine 10 of this embodiment has a hydrogen concentration sensor 58 for detecting the hydrogen concentration H within the crankcase 19. Furthermore, as... Figure 2 As shown, when the hydrogen concentration H detected by the hydrogen concentration sensor 58 is within the slow combustion range (S110: Yes), the control device 100 performs ignition processing by the ignition device 200 (S120).

[0044] Therefore, when the blow-by gas in the crankcase 19 containing hydrogen is ignited by the ignition device 200, the hydrogen can be burned slowly without a sharp increase in pressure.

[0045] (3) The internal combustion engine 10 is equipped with a turbocharger 24 that pressurizes the intake air flowing in the intake passage. When the internal combustion engine 10 equipped with such a turbocharger 24 is operating in the pressurized region, it is difficult to introduce fresh air into the crankcase 19. Therefore, the hydrogen concentration in the crankcase 19 is prone to increase. In this respect, in this embodiment, an ignition device 200 for igniting the gas in the crankcase 19 is provided in the internal combustion engine 10 equipped with such a turbocharger 24. Therefore, even though the internal combustion engine 10 is equipped with a turbocharger 24, it is possible to suppress the increase of hydrogen concentration.

[0046] <Example of Change>

[0047] Furthermore, this embodiment can be implemented with the following modifications. This embodiment and the following modifications can be combined with each other within the scope of technical non-contradiction.

[0048] The operating range where the hydrogen concentration in the crankcase 19 is within the slow combustion range can be determined through prior experiments. Therefore, when the internal combustion engine is operating within this range, ignition processing by the ignition device 200 can be performed. Even in this case, when the blow-by gas containing hydrogen in the crankcase 19 is burned by ignition by the ignition device 200, the hydrogen can burn slowly without a sharp pressure increase. Furthermore, the operating range described above can be exemplified by the operating range defined by the internal combustion engine speed and the internal combustion engine load rate.

[0049] As described above, in the internal combustion engine 10 equipped with turbocharger 24, when operating in the turbocharged region, the hydrogen concentration in the crankcase 19 tends to increase. Therefore, when the internal combustion engine 10 operates in such a turbocharged region, ignition processing by ignition device 200 can be performed. In this case, before the hydrogen concentration in the crankcase 19 increases, the blow-by gas in the crankcase 19 containing hydrogen is burned by ignition by ignition device 200, thus enabling slow combustion of hydrogen without a sharp pressure rise.

[0050] • The ignition device 200 can be any ignition device other than a spark plug. That is, the ignition device 200 can be any device that can ignite the gas in the crankcase 19, such as a heater.

[0051] The internal combustion engine 10 may not include a turbocharger 24. That is, even in a naturally aspirated internal combustion engine, when the engine load increases, the flow of fresh air from the intake manifold 20 via the first connecting passage 37 into the crankcase 19 becomes difficult, and therefore the hydrogen concentration in the crankcase 19 tends to increase. Therefore, even in such a naturally aspirated internal combustion engine, by including the ignition device 200 and the control device 100 described above, the same effects as in the above-described embodiment can be obtained.

[0052] The internal combustion engine 10 may be equipped with a fuel injection valve that injects fuel into the air intake 30.

[0053] The control device 100 includes a CPU and a memory, and is not limited to performing software processing. For example, the control device 100 may include a dedicated hardware circuit, such as an ASIC, that performs hardware processing on at least a portion of the software processing described in the above embodiments. That is, the control device 100 may include a processing circuit having any of the structures described in (a) to (c). (a) A processing circuit comprising: one or more processing devices that execute all of the above processing according to a program; and one or more program storage devices, such as a ROM, that stores the program. (b) A processing circuit comprising: one or more processing devices that execute a portion of the above processing according to a program and one or more program storage devices; and one or more dedicated hardware circuits that execute the remaining processing. (c) A processing circuit comprising: one or more dedicated hardware circuits that execute all of the above processing. The program storage device, i.e., the computer-readable medium, includes any usable medium that can be accessed by a general-purpose or special-purpose computer.

[0054] Symbol Explanation

[0055] 10-Internal combustion engine, 15-Piston, 16-Cylinder, 18-Crankshaft, 19-Crankshaft case, 20-Intake manifold, 23-Spark plug, 24-Turbocharger, 27-Intercooler, 28-Throttle valve, 29-Intake manifold, 30-Intake port, 32-Second connecting passage, 34-PCV valve, 35-PCV passage, 37-First connecting passage, 58-Hydrogen concentration sensor, 60-Pressure chamber, 70-Exhaust port, 81-Intake valve, 82-Exhaust valve, 84-Fuel injection valve, 90-Exhaust passage, 100-Control device, 200-Ignition device.

Claims

1. An internal combustion engine that uses hydrogen as fuel, said internal combustion engine being characterized by comprising: An ignition device that ignites the gases in the crankcase; and A control device that controls the ignition performed by the ignition device.

2. The internal combustion engine according to claim 1, characterized in that, The internal combustion engine has a sensor that detects the hydrogen concentration in the crankcase. When the range of hydrogen concentration for slow combustion of hydrogen in the crankcase is defined as the slow combustion range, When the hydrogen concentration detected by the sensor is within the slow combustion range, the control device performs ignition processing by the ignition device.

3. The internal combustion engine according to claim 1, characterized in that, When the range of hydrogen concentration for slow combustion of hydrogen in the crankcase is defined as the slow combustion range, When the internal combustion engine is running in the operating region where the hydrogen concentration in the crankcase is within the slow combustion range, the control device performs ignition processing by the ignition device.

4. The internal combustion engine according to claim 1, characterized in that, It is equipped with a turbocharger, which pressurizes the intake air flowing in the intake passage.

5. The internal combustion engine according to claim 4, characterized in that, When the internal combustion engine is running in the boosted region where it is boosted by the turbocharger, the control device performs the ignition process performed by the ignition device.

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