JP2024022175A - Control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress combustion of hydrogen gas within a sensor.

SOLUTION: An internal combustion engine 10 uses hydrogen as fuel. The internal combustion engine 10 comprises an exhaust passage 90 and an air-fuel ratio sensor 55 for detecting an air-fuel ratio, which is provided in the exhaust passage 90 and has a heater 55H. A control device 100 executes suppression processing to suppress heating by the heater 55H when a specified condition under which the concentration of hydrogen gas flowing into the exhaust passage 90 may exceed a predetermined value is satisfied.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2024,JPO&INPIT

Description

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

A sensor for detecting an air-fuel ratio is provided in an exhaust passage of an internal combustion engine. This sensor is provided with a heater for early activation of the detection element (for example, Patent Document 1).

Japanese Patent Application Publication No. 9-229899

By the way, in an internal combustion engine that uses hydrogen as fuel, there is a possibility that the concentration of unburned hydrogen gas flowing out into the exhaust passage becomes higher than a predetermined value. Therefore, when the above-described sensor is provided in the exhaust passage and the heater is heated, there is a risk that unburned hydrogen gas will be burned within the sensor.

A control device for an internal combustion engine that solves the above problems is a control device applied to an internal combustion engine that uses hydrogen as fuel. The internal combustion engine includes an exhaust passage and a sensor that is provided in the exhaust passage and has a heater and detects an air-fuel ratio. Then, the control device executes a suppression process to suppress heating of the heater when a prescribed condition is established in which the concentration of hydrogen gas flowing into the exhaust passage may be equal to or higher than a predetermined value.

According to this configuration, when there is a possibility that the concentration of hydrogen gas flowing into the exhaust passage becomes equal to or higher than a predetermined value, heating of the heater included in the sensor provided in the exhaust passage is suppressed. When the heating of the heater is suppressed, the temperature of the sensor decreases, so that combustion of hydrogen gas within the sensor can be suppressed.

FIG. 1 is a schematic diagram showing the configuration of an internal combustion engine in a first embodiment. It is a flowchart which shows the procedure of the process performed by the control device of the same embodiment. 7 is a flowchart showing a procedure of processing executed by a control device according to a second embodiment.

A first embodiment that embodies a control device for an internal combustion engine will be described below.
(First embodiment)
<Configuration of internal combustion engine>
As shown in FIG. 1, the internal combustion engine 10 includes a cylinder block 11, a cylinder head 12, a head cover 13, and an oil pan 14. A cylinder 16 in which a piston 15 is arranged so as to be able to reciprocate is provided within the cylinder block 11 .

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 of the intake valve 81 is provided with an intake-side variable valve timing mechanism 85 that is a variable valve mechanism that changes the valve timing (opening/closing timing) of the intake valve 81 . The exhaust port 70 is provided with an exhaust valve 82 . The drive system of the exhaust valve 82 is provided with an exhaust side valve timing variable mechanism 86, which is a variable valve mechanism that changes the valve timing (opening/closing timing) of the exhaust valve 82.

The cylinder head 12 also includes a port injection valve 83 that injects hydrogen as fuel into the intake port 30, an in-cylinder injection valve 84 that directly injects hydrogen as fuel into the combustion chamber 17, and a spark plug (not shown). (omitted) is provided.

A crank case 19 is provided at the bottom of the cylinder block 11 in which a crankshaft 18, which is the output shaft of the internal combustion engine 10, is accommodated. An oil pan 14 for storing lubricating oil is provided at the bottom of the crankcase 19.

An intake manifold 29 including 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, the surge tank 60, and the intake manifold 29 constitute an intake passage of the internal combustion engine 10.

In the intake pipe 20, from the upstream side, there are an air cleaner 21, an air flow meter 22, a compressor wheel 24C of a supercharger 24 driven using exhaust gas discharged from the combustion chamber 17, an intercooler 27, and a supercharging pressure sensor. 25 and a throttle valve 28 are installed. Further, an intake pressure sensor 54 is installed in the surge tank 60. Note that the opening degree of the throttle valve 28 is changed by an electric motor.

The air cleaner 21 filters intake air taken into the intake pipe 20. The supercharger 24 supercharges the air within the intake pipe 20. Further, the intercooler 27 cools the air after passing through the compressor wheel 24C. The throttle valve 28 adjusts the amount of intake air by adjusting the valve opening.

Air flow meter 22 detects intake air amount GA. Further, the boost pressure sensor 25 detects the boost pressure PTC, which is the pressure in the portion of the intake pipe 20 on the downstream side of the compressor wheel 24C. Further, the intake pressure PIM, which is the pressure inside the surge tank 60, is detected by the intake pressure sensor 54.

An exhaust passage 90 is connected downstream of the exhaust port 70. A housing that accommodates the turbine wheel 24T of the supercharger 24 is connected to the middle of the exhaust passage 90. Further, in the exhaust passage 90, an upstream portion of the turbine wheel 24T and a downstream portion of the turbine wheel 24T are communicated via a bypass passage 92. A waste gate valve (hereinafter referred to as WGV) 93 whose opening degree is adjusted by an actuator is provided in the middle of the bypass passage 92. This WGV 93 is a valve that adjusts the amount of exhaust gas flowing through the bypass passage 92, and as its opening degree becomes larger, the amount of exhaust gas that bypasses the turbine wheel 24T and passes through the bypass passage 92 increases. Therefore, the supercharging pressure of the intake air increased by the supercharger 24 becomes low.

In the exhaust passage 90, a catalyst 95 for purifying exhaust gas is provided at a downstream side of the bypass passage 92. Further, in the exhaust passage 90, an air-fuel ratio sensor 55 is provided upstream of the catalyst 95 to output an air-fuel ratio signal corresponding to the oxygen concentration in the exhaust gas and the amount of unburned fuel. This air-fuel ratio sensor 55 is provided with a heater 55H that heats the detection element of the air-fuel ratio sensor 55.

The internal combustion engine 10 is provided with a blowby gas processing device that processes gas leaked from the combustion chamber 17 into the crankcase 19 during the compression stroke and the combustion stroke, so-called blowby gas. This blowby gas processing device includes a suction path 32 for guiding blowby gas in the crankcase 19 to a main separator 31 that is an oil separator provided in the head cover 13. The end of the suction path 32 connected to the main separator 31 opens into the crankcase 19 .

The main separator 31 is connected to a surge tank 60 via a PCV (positive crankcase ventilation) valve 34, which is a differential pressure valve, and a PCV passage 35. The PCV valve 34 opens when the pressure inside the surge tank 60 becomes lower than the pressure inside the main separator 31 to allow blow-by gas to flow from the main separator 31 into the surge tank 60. These suction passage 32, main separator 31, PCV valve 34, and PCV passage 35 constitute a communication passage that communicates between surge tank 60, which constitutes a part of the intake passage, and crankcase 19.

For example, when the supercharging pressure of the supercharger 24 is low, the pressure in the surge tank 60 becomes lower than the pressure in the main separator 31. Therefore, the blow-by gas in the crankcase 19 is sucked into the surge tank 60 via the suction path 32, the main separator 31, the PCV valve 34, and the PCV passage 35. The sucked blow-by gas is sent to the combustion chamber 17 together with the intake air and is burned.

Further, an ejector 40 is connected to the main separator 31 via a connection passage 41. The ejector 40 is provided in the middle of a bypass passage 36 that connects the intake pipe 20 upstream of the compressor wheel 24C and the intake pipe 20 downstream of the compressor wheel 24C. The ejector 40 includes a constriction portion for generating negative pressure by the venturi effect.

The blow-by gas treatment device also includes an atmospheric air introduction path 37 for introducing intake air into the crankcase 19 for scavenging. One end of both ends of the atmosphere introduction path 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 , passes through the cylinder head 12 and the cylinder block 11 , and is connected to the crankcase 19 . An atmosphere-side separator 38, which is an oil separator installed inside the head cover 13, is provided in the middle of the atmosphere introduction path 37.

When the supercharging pressure of the supercharger 24 is high, negative pressure is generated in the ejector 40 due to air flowing in the bypass passage 36 from the downstream side to the upstream side of the compressor wheel 24C. Then, due to the negative pressure generated in the ejector 40, the blow-by gas in the crankcase 19 is sucked into the ejector 40 via the suction path 32, the main separator 31, and the connection path 41. The blow-by gas sucked into the ejector 40 is introduced together with air through the bypass passage 36 into the intake pipe 20 upstream of the compressor wheel 24C. The blow-by gas introduced into the intake pipe 20 is sent to the combustion chamber 17 together with the intake air and is burned.

The control device 100 controls the internal combustion engine 10, and controls a throttle valve 28, a port injection valve 83, an in-cylinder injection valve 84, a spark plug, an intake valve timing variable mechanism 85, an exhaust valve timing variable mechanism 86, a WGV 93, etc. Operate various target devices.

The control device 100 includes a central processing unit (hereinafter referred to as CPU) 110, a memory 120 in which control programs and data are stored, and the like. Then, the control device 100 executes various control-related processes by having the CPU 110 execute programs stored in the memory 120.

Detection signals from the above-mentioned air flow meter 22, boost pressure sensor 25, intake pressure sensor 54, and air-fuel ratio sensor 55 are input to the control device 100. Furthermore, a detection signal from a crank angle sensor 51 that detects the rotation angle (crank angle) of the crankshaft 18 is also input to the control device 100 in order to calculate the engine rotation speed NE. The control device 100 also receives detection signals from a vehicle speed sensor 53 that detects the vehicle speed SP of the vehicle equipped with the internal combustion engine 10, an accelerator operation amount sensor 52 that detects the accelerator operation amount ACP that is the operation amount of the accelerator pedal, etc. be done. Note that the control device 100 calculates the engine load factor KL based on the engine rotational speed NE and the intake air amount GA. The engine load factor KL is a parameter that determines the amount of air filled into the combustion chamber 17, and is the ratio of the amount of inflowing air per combustion cycle of one cylinder to the reference amount of inflowing air. Note that the reference inflow air amount is variably set according to the engine rotation speed NE.

The control device 100 calculates a target output Pe, which is a target value of the output required of the internal combustion engine 10, based on the accelerator operation amount ACP and the vehicle speed SP. Then, when the target output Pe is large, control is executed to make the air-fuel ratio of the air-fuel mixture smaller than when the target output Pe is small. More specifically, the control device 100 basically maintains the throttle valve 28 at an opening degree greater than a predetermined value, for example, at an opening degree near full open. Then, the required injection amount Qd is set such that the larger the target output Pe is, the larger the required injection amount Qd is. The required injection amount Qd is a target value of fuel injected from the port injection valve 83 and the in-cylinder injection valve 84. Then, the control device 100 controls the port injection valve 83 and the in-cylinder injection valve 84 so that the required injection amount Qd is obtained. In this way, in the internal combustion engine 10, output adjustment is performed by changing the air-fuel ratio of the air-fuel mixture through adjustment of the fuel injection amount.

Note that the control device 100 automatically stops the operation of the internal combustion engine 10 when the target output Pe is "0". Then, after the automatic stop, when the target output Pe becomes larger than "0", the control device 100 starts the internal combustion engine 10 and resumes operation. In this way, the control device 100 automatically stops and starts the internal combustion engine 10.

Further, the control device 100 calculates target valve timings for the intake valve 81 and the exhaust valve 82 based on the engine rotational speed NE, the engine load factor KL, and the like. Then, the intake valve timing variable mechanism 85 and the exhaust valve timing variable mechanism 86 are driven and controlled based on the target valve timing and the like.

Furthermore, the control device 100 calculates the target supercharging pressure PTCp based on the engine rotation speed NE, the engine load factor KL, and the like. The supercharging pressure of the supercharger 24 is then controlled by adjusting the opening of the WGV 93 based on the target supercharging pressure PTCp and the like.

<Suppression processing of this embodiment>
In the internal combustion engine 10 that uses hydrogen as fuel, there is a risk that the concentration of hydrogen gas flowing into the exhaust passage 90 will exceed a predetermined combustible value. For example, during the period from when the internal combustion engine starts to when the combustion of the air-fuel mixture becomes stable, the amount of unburned hydrogen gas contained in the exhaust gas increases, so the concentration of hydrogen gas flowing into the exhaust passage 90 increases. There is a possibility that it will become higher than the predetermined value. If the heater 55H of the air-fuel ratio sensor 55 is heated in such a situation where the concentration of hydrogen gas is higher than a predetermined value, there is a risk that unburned hydrogen gas will be combusted within the air-fuel ratio sensor 55.

Therefore, the starting time of the internal combustion engine 10 is set as a specified condition in which the concentration of hydrogen gas flowing into the exhaust passage 90 may exceed a predetermined value. When this specified condition is satisfied, the control device 100 executes a suppression process to suppress heating of the heater 55H.

FIG. 2 shows a processing procedure for executing the suppression processing. The process shown in FIG. 2 is realized by the control device 100 repeatedly executing the process at predetermined intervals. Note that in the following, the step number of each process is expressed by a number prefixed with "S".

In the series of processes shown in FIG. 2, the control device 100 first determines whether or not it is time to start the engine (S100). The control device 100 makes an affirmative determination in the process of S100 from the time when the engine start is started due to a request to start the internal combustion engine 10, until it is determined that the engine start has been completed. Note that the starting request includes the above-mentioned request for starting the engine by automatic starting, and the request for starting the engine by turning on the ignition switch by the vehicle driver. Further, the control device 100 determines that engine starting has been completed, for example, when the engine rotational speed NE exceeds a prescribed determination value NEf.

If it is determined in the process of S100 that the engine is starting (S100: YES), the control device 100 determines whether or not the combustion of the air-fuel mixture is stable (S110). In the process of S110, the control device 100 determines that the combustion of the air-fuel mixture is stable when the engine rotational speed NE is equal to or higher than a prescribed determination value NEa. Note that the determination value NEa is a smaller value than the determination value NEf.

If it is determined in the process of S110 that the combustion of the air-fuel mixture is not stable (S110: NO), the control device 100 performs a first suppression process of suppressing heating of the heater 55H by stopping energization of the heater 55H. (S120).

Next, the control device 100 executes a second suppression process of suppressing the energization of the detection element of the air-fuel ratio sensor 55 by stopping the energization of the detection element (S130).
On the other hand, if it is determined in the process of S110 that the combustion of the air-fuel mixture is stable (S110: YES), the control device 100 stops energizing the heater 55H (S140).

Next, the control device 100 energizes the detection element of the air-fuel ratio sensor 55 (S150).
Note that when the control device 100 completes the process of S130 and the process of S150, or when a negative determination is made in the process of S100, the control device 100 temporarily ends the series of processes shown in FIG. 2.

<Action and effect>
The operation and effects of this embodiment will be explained.
(1-1) During the period from the start of the internal combustion engine 10 until the combustion of the air-fuel mixture becomes stable, the concentration of hydrogen gas flowing into the exhaust passage 90 may become higher than a predetermined value. Therefore, in the present embodiment, the first suppression process is executed during the period from when the engine starts to when it is determined that the combustion of the air-fuel mixture is stabilized. By executing this first suppression process, heating of the heater 55H is suppressed, so the temperature of the air-fuel ratio sensor 55 decreases. Therefore, when the engine is started, combustion of hydrogen gas within the sensor can be suppressed.

(1-2) When the detection element of the air-fuel ratio sensor 55 is energized, the detection element functions as a reactor. Therefore, when the detection element is energized, the ignition temperature of hydrogen gas tends to be lower than when it is not energized. In this regard, in the present embodiment, when the first suppression process is executed, the second suppression process of stopping energization to the detection element is also executed. Therefore, it is possible to lower the ignition temperature of hydrogen gas, and this also makes it possible to suppress combustion of hydrogen gas within the sensor.

(Second embodiment)
Next, a second embodiment that embodies a control device for an internal combustion engine will be described.
In the internal combustion engine 10 that uses hydrogen as fuel, even when the operation is stopped, there is a possibility that the concentration of hydrogen gas flowing out into the exhaust passage 90 will exceed a predetermined value that allows combustion. For example, when the internal combustion engine 10 is stopped, the piston 15 repeatedly moves up and down until the crankshaft 18 stops rotating. Due to this movement of the piston 15, hydrogen gas in the blow-by gas accumulated in the crank case 19 flows into the intake passage via the blow-by treatment device described above. The hydrogen gas that has flowed into the intake passage flows into the exhaust passage 90 without being combusted in the combustion chamber 17. Furthermore, hydrogen gas in the blow-by gas accumulated in the crankcase 19 flows into the combustion chamber 17 through the gap between the cylinder 16 and the piston 15, for example, by the vertical movement of the piston 15. The hydrogen gas that has flowed into the combustion chamber 17 flows into the exhaust passage 90 without being combusted in the combustion chamber 17 . Therefore, even when the internal combustion engine 10 is stopped, the concentration of hydrogen gas flowing into the exhaust passage 90 may become higher than a predetermined value. If the heater 55H of the air-fuel ratio sensor 55 is heated in such a situation where the concentration of hydrogen gas is higher than a predetermined value, there is a risk that unburned hydrogen gas will be combusted within the air-fuel ratio sensor 55.

Therefore, the time when the operation of the internal combustion engine 10 is stopped is set as a specified condition under which the concentration of hydrogen gas flowing out into the exhaust passage 90 may exceed a predetermined value. When this specified condition is satisfied, the control device 100 executes a suppression process to suppress heating of the heater 55H.

<Suppression processing of this embodiment>
FIG. 3 shows a processing procedure for executing the suppression processing in this embodiment. The process shown in FIG. 3 is realized by the control device 100 repeatedly executing the process at predetermined intervals.

In the series of processes shown in FIG. 3, the control device 100 first determines whether it is time to stop the operation of the internal combustion engine 10, and more specifically, whether there is a stop request to stop the operation of the internal combustion engine 10. (S200). Note that the stop request includes a request to stop operation due to the automatic stop described above, a request to stop operation due to an ignition switch off operation by the vehicle driver, and the like.

If there is a stop request (S200: YES), the control device 100 executes a first suppression process of suppressing heating of the heater 55H by stopping the energization of the heater 55H (S2100).

Next, the control device 100 executes a second suppression process of suppressing the energization of the detection element of the air-fuel ratio sensor 55 by stopping the energization of the detection element (S220).
Next, the control device 100 determines whether the sensor temperature THs is equal to or lower than the determination value THsref (S230). The sensor temperature THs is the temperature of the air-fuel ratio sensor 55. The control device 100 calculates the sensor temperature THs based on, for example, the resistance value of the air-fuel ratio sensor 55 and the elapsed time after the heater 55H is de-energized. Note that the sensor temperature THs may be actually measured. Further, the determination value THsref is a predetermined value, and an example thereof is the lowest temperature at which hydrogen gas may ignite.

When determining that the sensor temperature THs is equal to or lower than the determination value THsref (S230: YES), the control device 100 executes the operation stop of the internal combustion engine 10 (S240). In the process of S240, the control device 100 stops the operation of the internal combustion engine 10 by stopping power to the spark plug and stopping fuel injection from each of the injection valves 83 and 84.

Note that when the control device 100 completes the process of S240 or makes a negative determination in the process of S200 or the process of S230, the control device 100 temporarily ends the series of processes shown in FIG. 3.
<Action and effect>
The operation and effects of this embodiment will be explained.

(2-1) When the operation of the internal combustion engine 10 is stopped, the concentration of hydrogen gas flowing out into the exhaust passage 90 may become higher than a predetermined value. Therefore, in the present embodiment, when there is a stop request to stop the operation of the internal combustion engine 10, the first suppression process is executed until it is determined that the sensor temperature THs is equal to or lower than the determination value THsref. By executing this first suppression process, heating of the heater 55H is suppressed, so the temperature of the air-fuel ratio sensor 55 decreases. Therefore, when the engine is stopped, combustion of hydrogen gas within the sensor can be suppressed.

(2-2) Even if a stop request occurs, stopping the operation of the internal combustion engine 10 is delayed until the sensor temperature THs becomes equal to or less than the determination value THsref. Therefore, the inflow of hydrogen gas into the exhaust passage 90 due to the stoppage of operation occurs only after the combustion of hydrogen gas within the sensor is suppressed. Therefore, this also makes it possible to suppress combustion of hydrogen gas within the sensor.

(2-3) When the detection element of the air-fuel ratio sensor 55 is energized, the detection element functions as a reactor. Therefore, when the detection element is energized, the ignition temperature of hydrogen gas tends to be lower than when it is not energized. In this regard, in this embodiment as well, when the first suppression process is executed, the second suppression process of stopping energization to the detection element is also executed. Therefore, it is possible to lower the ignition temperature of hydrogen gas, and this also makes it possible to suppress combustion of hydrogen gas within the sensor.

<Example of change>
Note that each of the above embodiments can be modified and implemented as follows. Each embodiment and the following modification examples can be implemented in combination with each other within a technically consistent range.

- In the process of S110 in the first embodiment, whether or not the combustion of the air-fuel mixture is stable is determined based on the engine rotation speed NE, but other methods may be used.
For example, it may be determined that the combustion of the air-fuel mixture is stable when the intake air amount GA is equal to or greater than the threshold value GAref. Note that when the engine speed NE is low, the flow rate of intake air flowing into the combustion chamber 17 is slower than when it is high, so mixing of the air-fuel mixture tends to be difficult and combustion tends to become unstable. Therefore, even if the intake air amount GA is the same, the lower the engine speed NE, the more unstable the combustion of the air-fuel mixture becomes. Therefore, if the threshold value GAref is variably set so that the lower the engine speed NE is, the larger the value of the threshold value GAref becomes, the accuracy of determining whether or not the combustion of the air-fuel mixture is stable can be improved. Become.

Further, for example, the variation amount ΔNE of the engine rotational speed NE is calculated. Then, it may be determined that the combustion of the air-fuel mixture is stable when the calculated variation amount ΔNE is greater than or equal to the threshold value ΔNEref. In this case as well, if the threshold value ΔNEref is variably set so that the lower the engine speed NE is, the larger the value of the threshold value ΔNEref becomes, the accuracy of determining whether or not the combustion of the air-fuel mixture is stable can be improved. will improve.

- In the second embodiment, the operation of the internal combustion engine 10 is stopped after the sensor temperature THs becomes equal to or less than the determination value THsref. In addition, when there is a stop request, the internal combustion engine 10 may be stopped, and the first suppression process and the second suppression process described above may be executed. Even in this case, effects other than the above (2-2) can be obtained.

- In each embodiment, execution of the second suppression process may be omitted.
- In the first suppression process described above, power supply to the heater 55H was stopped. In addition, the first suppression process may be a process of energizing the heater 55H and reducing the amount of power supplied to the heater 55H compared to when the first suppression process is not executed. Also in this case, heating of the heater 55H can be suppressed by executing the first suppression process.

- In the second suppression process described above, power supply to the detection element was stopped. In addition, the second suppression process may be a process of energizing the detection element and reducing the amount of power supplied to the detection element compared to when the second suppression process is not executed. In this case as well, by executing the second suppression process, the energization to the detection element can be suppressed, so that the ignition temperature of hydrogen gas is reduced.

- In the second embodiment, the operation of the internal combustion engine 10 is stopped after the sensor temperature THs becomes equal to or less than the determination value THsref. In addition, when there is a stop request, the internal combustion engine 10 may be stopped, and the first suppression process and the second suppression process described above may be executed.

- The air-fuel ratio sensor 55 is exemplified as a sensor that is provided in the exhaust passage 90 and has a heater and detects the air-fuel ratio. In addition, an oxygen sensor that can detect whether the air-fuel ratio is rich or lean may be provided.

- Although a sensor with a heater that detects the air-fuel ratio is provided on the upstream side of the catalyst 95, a sensor with a heater that detects the air-fuel ratio may also be provided on the downstream side of the catalyst 95. The above-described suppression process may also be performed for the above-mentioned.

- Although the PCV passage 35 is connected to the surge tank 60, the connection part may be changed as appropriate as long as it is a part downstream of the throttle valve 28 in the intake passage.
- The internal combustion engine 10 may include only either the port injection valve 83 or the in-cylinder injection valve 84.

- It is not essential for the internal combustion engine 10 to include the supercharger 24 and the ejector 40.
- It is not essential for the internal combustion engine 10 to include the variable intake valve timing mechanism 85 and the variable exhaust valve timing mechanism 86.

- The control device 100 may execute both the processes shown in FIGS. 2 and 3. Further, the control device 100 may execute only one of the processes shown in FIG. 2 or 3.
- The control device is not limited to one that includes the CPU 110 and the memory 120 and executes software processing. For example, a dedicated hardware circuit such as an ASIC may be provided to process at least a part of what was processed by software in the above embodiments by hardware. That is, the control device may have any of the following configurations (a) to (c). (a) It includes a processing device that executes all of the above processing according to a program, and a program storage device such as a ROM that stores the program. (b) It includes a processing device and a program storage device that execute part of the above processing according to a program, and a dedicated hardware circuit that executes the remaining processing. (c) A dedicated hardware circuit is provided to execute all of the above processing. Here, the number of software execution devices including a processing device and a program storage device, or a dedicated hardware circuit may be one or more than one.

<Related technical ideas>
The technical ideas that can be understood from each of the above embodiments and modifications will be described.
(Additional note 1)
A control device applied to an internal combustion engine that uses hydrogen as fuel,
The internal combustion engine includes an exhaust passage and a sensor that is provided in the exhaust passage and has a heater and detects an air-fuel ratio,
A control device for an internal combustion engine that executes a suppression process for suppressing heating of the heater when a specified condition is established in which the concentration of hydrogen gas flowing into the exhaust passage may exceed a predetermined value.

(Additional note 2)
The specified condition is when the internal combustion engine is started,
The control device for an internal combustion engine according to supplementary note 1, wherein the suppression process is a process that is executed after starting the internal combustion engine until combustion of the air-fuel mixture becomes stable.

(Additional note 3)
The prescribed condition is when the operation of the internal combustion engine is stopped;
The control device for an internal combustion engine according to Supplementary Note 1 or 2, wherein the suppression process is a process that is executed after a request to stop operation of the internal combustion engine is issued until the temperature of the sensor becomes equal to or lower than a predetermined temperature.

(Additional note 4)
The control device for an internal combustion engine according to supplementary note 3, which executes processing for delaying the shutdown of the internal combustion engine until the temperature of the sensor becomes equal to or lower than the predetermined temperature after the shutdown request occurs.

(Additional note 5)
Any one of Supplementary notes 1 to 4, wherein when the suppression process is a first suppression process, when executing the first suppression process, a second suppression process is executed to suppress energization to a detection element included in the sensor. A control device for an internal combustion engine according to paragraph 1.

10...Internal combustion engine 19...Crank case 20...Intake pipe 24...Supercharger 28...Throttle valve 29...Intake manifold 32...Suction path 34...PCV valve 35...PCV passage 36...Bypass passage 37...Atmospheric introduction path 40...Ejector 55 ...Air-fuel ratio sensor 55H...Heater 60...Surge tank 81...Intake valve 82...Exhaust valve 83...Port injection valve 84...In-cylinder injection valve 90...Exhaust passage 92...Bypass passage 93...Waste gate valve (WGV)
100...Control device 110...Central processing unit (CPU)
120...Memory

Claims (5)

A control device applied to an internal combustion engine that uses hydrogen as fuel,
The internal combustion engine includes an exhaust passage and a sensor that is provided in the exhaust passage and has a heater and detects an air-fuel ratio,
A control device for an internal combustion engine that executes a suppression process for suppressing heating of the heater when a specified condition is established in which the concentration of hydrogen gas flowing into the exhaust passage may exceed a predetermined value. The specified condition is when the internal combustion engine is started,
The control device for an internal combustion engine according to claim 1, wherein the suppression process is a process that is executed after starting the internal combustion engine until combustion of the air-fuel mixture is stabilized. The prescribed condition is when the operation of the internal combustion engine is stopped;
The control device for an internal combustion engine according to claim 1, wherein the suppression process is a process that is executed after a request to stop operation of the internal combustion engine is issued until the temperature of the sensor becomes equal to or lower than a predetermined temperature. The control device for an internal combustion engine according to claim 3, wherein processing for delaying the operation stop of the internal combustion engine is executed until the temperature of the sensor becomes equal to or lower than the predetermined temperature after the operation stop request is issued. The internal combustion engine according to claim 1, wherein when the suppression process is a first suppression process, when executing the first suppression process, a second suppression process is executed to suppress energization to a detection element included in the sensor. Control device.

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