JP7782389B2 - Control device for internal combustion engine - Google Patents

Description

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

A sensor that detects the air-fuel ratio is installed in the exhaust passage of an internal combustion engine. This sensor is equipped with a heater to quickly activate the detection element (see, for example, Patent Document 1).

Japanese Patent Application Publication No. 9-229899

However, in internal combustion engines that use hydrogen as fuel, the concentration of unburned hydrogen gas that flows into the exhaust passage may exceed a predetermined value. Therefore, if the above-mentioned sensor is installed in the exhaust passage and the heater is used, there is a risk that unburned hydrogen gas will burn within the sensor.

The internal combustion engine control device that solves the above problem is a control device applied to an internal combustion engine that uses hydrogen as fuel. The internal combustion engine is equipped with an exhaust passage and a sensor that has a heater and detects the air-fuel ratio, which is provided in the exhaust passage. The control device then executes a suppression process to suppress heating of the heater when a specified condition is met that indicates that the concentration of hydrogen gas flowing into the exhaust passage may exceed a predetermined value.

With this configuration, if there is a possibility that the concentration of hydrogen gas flowing into the exhaust passage will exceed a predetermined value, heating of the heater provided in the sensor installed in the exhaust passage is suppressed. Suppressing heater heating reduces the temperature of the sensor, thereby preventing hydrogen gas from burning within the sensor.

1 is a schematic diagram showing a configuration of an internal combustion engine according to a first embodiment. 4 is a flowchart showing a procedure of a process executed by the control device of the embodiment. 10 is a flowchart showing a procedure of a process executed by a control device of a second embodiment.

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

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

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

Below the cylinder block 11 is a crankcase 19 that houses the crankshaft 18, which is the output shaft of the internal combustion engine 10. Below the crankcase 19 is an oil pan 14 that stores lubricating oil.

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 together form the intake passage of the internal combustion engine 10.

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

The air cleaner 21 filters the intake air taken into the intake pipe 20. The supercharger 24 supercharges the air in the intake pipe 20. The intercooler 27 cools the air after it passes through the compressor wheel 24C. The throttle valve 28 regulates the amount of intake air by adjusting the valve opening.

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

An exhaust passage 90 is connected downstream of the exhaust port 70. A housing that houses the turbine wheel 24T of the turbocharger 24 is connected midway through the exhaust passage 90. The upstream portion of the exhaust passage 90 from the turbine wheel 24T is connected to the downstream portion of the turbine wheel 24T via a bypass passage 92. A wastegate valve (hereinafter referred to as WGV) 93, the opening of which is adjusted by an actuator, is provided midway through the bypass passage 92. The WGV 93 is a valve that adjusts the amount of exhaust gas flowing through the bypass passage 92; the greater its opening, the greater the amount of exhaust gas that bypasses the turbine wheel 24T and passes through the bypass passage 92. Therefore, the intake boost pressure increased by the turbocharger 24 decreases.

A catalyst 95 for purifying exhaust gas is provided in the exhaust passage 90 downstream of the bypass passage 92. Furthermore, an air-fuel ratio sensor 55 is provided in the exhaust passage 90 upstream of the catalyst 95. This air-fuel ratio sensor 55 outputs an air-fuel ratio signal corresponding to the oxygen concentration and amount of unburned fuel in the exhaust gas. A heater 55H is provided in the air-fuel ratio sensor 55 to heat the detection element of the air-fuel ratio sensor 55.

The internal combustion engine 10 is equipped with a blow-by gas treatment device that treats gas that leaks from the combustion chamber 17 into the crankcase 19 during the compression stroke or combustion stroke, known as blow-by gas. This blow-by gas treatment device has a suction passage 32 that guides the blow-by gas in the crankcase 19 to a main separator 31, an oil separator provided in the head cover 13. The end of the suction passage 32, connected to the main separator 31, opens into the crankcase 19.

The main separator 31 is connected to the 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 in the surge tank 60 becomes lower than the pressure in the main separator 31, allowing blow-by gas to flow from the main separator 31 into the surge tank 60. The suction passage 32, main separator 31, PCV valve 34, and PCV passage 35 form a communication passage that connects the surge tank 60, which forms part of the intake passage, with the crankcase 19.

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

An ejector 40 is also connected to the main separator 31 via a connecting passage 41. The ejector 40 is located midway through the bypass passage 36, which connects the intake pipe 20 upstream of the compressor wheel 24C with the intake pipe 20 downstream of the compressor wheel 24C. The ejector 40 is equipped with a throttle section for generating negative pressure by the Venturi effect.

The blow-by gas treatment device also has an atmospheric air introduction passage 37 for introducing intake air into the crankcase 19 for scavenging. One end of the atmospheric air introduction passage 37 is connected to the intake pipe 20 between the air cleaner 21 and the compressor wheel 24C. The atmospheric air introduction passage 37 passes through the head cover 13, passes through the interior of the cylinder head 12 and cylinder block 11, and connects to the crankcase 19. An atmospheric air separator 38, an oil separator installed inside the head cover 13, is provided midway along the atmospheric air introduction passage 37.

When the boost pressure of the turbocharger 24 is high, air flows through the bypass passage 36 from downstream to upstream of the compressor wheel 24C, creating negative pressure in the ejector 40. The negative pressure generated in the ejector 40 causes blow-by gas in the crankcase 19 to be drawn into the ejector 40 via the suction passage 32, main separator 31, and connecting passage 41. The blow-by gas drawn into the ejector 40 is then introduced, together with air, via 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 combusted.

The control device 100 controls the internal combustion engine 10 and operates various controllable devices such as the throttle valve 28, port injection valve 83, in-cylinder injection valve 84, spark plug, intake side variable valve timing mechanism 85, exhaust side variable valve timing mechanism 86, and WGV 93.

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

The control device 100 receives detection signals from the air flow meter 22, boost pressure sensor 25, intake pressure sensor 54, and air-fuel ratio sensor 55. The control device 100 also receives a detection signal from a crank angle sensor 51 that detects the rotation angle (crank angle) of the crankshaft 18 to calculate the engine 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 pedal operation amount ACP, and other sensors. The control device 100 calculates the engine load factor KL based on the engine speed NE and the intake air amount GA. The engine load factor KL is a parameter that determines the amount of air charged into the combustion chamber 17 and is the ratio of the inflow air amount per combustion cycle of one cylinder to a reference inflow air amount. The reference inflow air amount is variably set according to the engine speed NE.

The control device 100 calculates the target output Pe, which is the target value of the output required of the internal combustion engine 10, based on the accelerator pedal depression amount ACP and the vehicle speed SP. When the target output Pe is high, the control device 100 executes control to reduce the air-fuel ratio of the mixture compared to when the target output Pe is low. More specifically, the control device 100 basically maintains the throttle valve 28 at an opening equal to or greater than a preset value, for example, near full open. The control device 100 then sets the required injection amount Qd so that it increases as the target output Pe increases. The required injection amount Qd is a target value for the fuel injected from the port injection valve 83 and the in-cylinder injection valve 84. The control device 100 then controls the port injection valve 83 and the in-cylinder injection valve 84 to obtain the required injection amount Qd. In this way, the internal combustion engine 10 adjusts the output by changing the air-fuel ratio of the mixture through adjustment of the fuel injection amount.

Note that the control device 100 automatically stops 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 greater 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.

The control device 100 also calculates the target valve timing for the intake valve 81 and the exhaust valve 82 based on the engine rotation speed NE, the engine load factor KL, etc. Then, based on the target valve timing, etc., it controls the drive of the intake side variable valve timing mechanism 85 and the exhaust side variable valve timing mechanism 86.

The control device 100 also calculates the target boost pressure PTCp based on the engine speed NE, engine load factor KL, etc. Then, it controls the boost pressure of the turbocharger 24 by adjusting the opening of the WGV 93 based on the target boost pressure PTCp, etc.

<Suppression Processing of This Embodiment>
In an 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 begins to start until combustion of the air-fuel mixture stabilizes, the amount of unburned hydrogen gas contained in the exhaust increases, and the concentration of hydrogen gas flowing into the exhaust passage 90 may exceed 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 the predetermined value, there is a risk that the unburned hydrogen gas will burn within the air-fuel ratio sensor 55.

Therefore, the start-up of the internal combustion engine 10 is set as a specified condition under which the concentration of hydrogen gas flowing into the exhaust passage 90 may exceed a predetermined value. If this specified condition is met, the control device 100 executes a suppression process to suppress heating of the heater 55H.

Figure 2 shows the processing procedure for executing the suppression process. The process shown in Figure 2 is realized by the control device 100 repeatedly executing it at predetermined intervals. Note that below, the step number of each process will be represented by a number preceded by an "S."

In the series of processes shown in FIG. 2, the control device 100 first determines whether the engine is being started (S100). The control device 100 makes a positive determination in S100 from the time engine start is initiated in response to a start request for the internal combustion engine 10 until it determines that engine start is complete. Note that start requests include an engine start request due to the automatic start described above, and an engine start request due to the vehicle driver turning on the ignition switch. Furthermore, the control device 100 determines that engine start is complete when, for example, the engine rotation speed NE exceeds a specified determination value NEf.

If the process of S100 determines that the engine is starting (S100: YES), the control device 100 determines whether 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 if the engine rotation speed NE is equal to or greater than a specified judgment value NEa. Note that the judgment value NEa is a value smaller than the above-mentioned judgment value NEf.

If the control device 100 determines in the processing of S110 that the combustion of the air-fuel mixture is unstable (S110: NO), it executes a first suppression process to suppress heating of the heater 55H by stopping the supply of electricity to the heater 55H (S120).

Next, the control device 100 executes a second suppression process to suppress 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, when 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).
When the control device 100 has completed the process of S130 or 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.

<Action and effect>
The operation and effects of this embodiment will be described.
(1-1) During the period from when the internal combustion engine 10 begins to start until combustion of the air-fuel mixture stabilizes, there is a possibility that the concentration of hydrogen gas flowing into the exhaust passage 90 will be higher than a predetermined value. Therefore, in this embodiment, the first suppression process is executed during the period from when the engine starts to when it is determined that combustion of the air-fuel mixture has stabilized. Execution of this first suppression process suppresses heating of the heater 55H, thereby reducing the temperature of the air-fuel ratio sensor 55. Therefore, when the engine starts, it is possible to suppress combustion of hydrogen gas within the sensor.

(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 this embodiment, when the first suppression process is performed, the second suppression process, which stops the energization of the detection element, is also performed. This makes it possible to lower the ignition temperature of hydrogen gas, which also makes it possible to suppress the combustion of hydrogen gas within the sensor.

Second Embodiment
Next, a second embodiment of a control device for an internal combustion engine will be described.
In an internal combustion engine 10 that uses hydrogen as fuel, even when operation is stopped, the concentration of hydrogen gas flowing into the exhaust passage 90 may exceed a predetermined combustible concentration. For example, when the internal combustion engine 10 is stopped, the piston 15 repeatedly moves up and down until the rotation of the crankshaft 18 stops. This movement of the piston 15 causes hydrogen gas in the blow-by gas accumulated in the crankcase 19 to flow into the intake passage via the blow-by treatment device described above. The hydrogen gas that flows into the intake passage flows into the exhaust passage 90 without being combusted in the combustion chamber 17. Furthermore, the hydrogen gas in the blow-by gas accumulated in the crankcase 19 flows into the combustion chamber 17, for example, through the gap between the cylinder 16 and the piston 15, due to the up and down movement of the piston 15. The hydrogen gas that flows into the combustion chamber 17 flows into the exhaust passage 90 without being combusted in the combustion chamber 17. Therefore, even when operation of the internal combustion engine 10 is stopped, the concentration of hydrogen gas flowing into the exhaust passage 90 may exceed a predetermined value. If the heater 55H of the air-fuel ratio sensor 55 is heated in a situation where the concentration of hydrogen gas is higher than a predetermined value, there is a risk that unburned hydrogen gas will be burned inside the air-fuel ratio sensor 55.

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

<Suppression Processing of This Embodiment>
3 shows a processing procedure for executing the suppression processing in this embodiment. The processing shown in FIG. 3 is realized by the control device 100 repeatedly executing it 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). Stop requests include a request to stop operation due to the automatic stop described above, a request to stop operation due to the vehicle driver turning off the ignition switch, etc.

If a stop request has been made (S200: YES), the control device 100 executes a first suppression process to suppress heating of the heater 55H by stopping the supply of electricity to the heater 55H (S2100).

Next, the control device 100 executes a second suppression process to suppress 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 a reference 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 or the elapsed time since the heater 55H was de-energized. The sensor temperature THs may also be measured. The reference value THsref is a predetermined value, and an example thereof is the lowest temperature at which hydrogen gas may ignite.

If it is determined that the sensor temperature THs is equal to or lower than the reference value THsref (S230: YES), the control device 100 shuts down the internal combustion engine 10 (S240). In the processing of S240, the control device 100 shuts down the internal combustion engine 10 by cutting off the power supply to the spark plugs and by stopping fuel injection from each injection valve 83, 84.

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

(2-1) When the operation of the internal combustion engine 10 is stopped, there is a possibility that the concentration of hydrogen gas flowing into the exhaust passage 90 will exceed a predetermined value. Therefore, in this embodiment, when there is a 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 reference value THsref. Execution of this first suppression process suppresses heating of the heater 55H, thereby reducing the temperature of the air-fuel ratio sensor 55. Therefore, when the engine is stopped, combustion of hydrogen gas within the sensor can be suppressed.

(2-2) Even if a stop request is issued, the shutdown of the internal combustion engine 10 is delayed until the sensor temperature THs falls below the reference value THsref. Therefore, the inflow of hydrogen gas into the exhaust passage 90 due to the shutdown occurs only after the combustion of hydrogen gas within the sensor is suppressed. This also makes it possible to suppress the 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, when the first suppression process is performed, the second suppression process, which stops the energization of the detection element, is also performed. Therefore, it is possible to lower the ignition temperature of hydrogen gas, which also makes it possible to suppress the combustion of hydrogen gas within the sensor.

<Example of change>
The above-described embodiments can be modified as follows: The embodiments and the following modifications can be combined with each other within the scope of technical compatibility.

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. However, the determination may be made by other methods.
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. When the engine speed NE is low, the flow rate of the intake air flowing into the combustion chamber 17 is slower than when the engine speed NE is high, which tends to make the mixture less well mixed and result in unstable combustion. Therefore, even with the same intake air amount GA, the lower the engine speed NE, the more likely the combustion of the air-fuel mixture is to become unstable. Therefore, if the threshold value GAref is variably set so that the value of the threshold value GAref increases as the engine speed NE decreases, the accuracy of determining whether the combustion of the air-fuel mixture is stable can be improved.

Alternatively, for example, the amount of fluctuation ΔNE in the engine rotation speed NE may be calculated. Then, if the calculated amount of fluctuation ΔNE is equal to or greater than a threshold value ΔNEref, it may be determined that the combustion of the air-fuel mixture is stable. Even in this case, if the threshold value ΔNEref is variably set so that the lower the engine rotation speed NE, the greater the value of the threshold value ΔNEref, thereby improving the accuracy of determining whether the combustion of the air-fuel mixture is stable.

- In the second embodiment, the internal combustion engine 10 is stopped after the sensor temperature THs becomes equal to or lower than the reference value THsref. Alternatively, if there is a stop request, the internal combustion engine 10 may be stopped and the first suppression process and second suppression process described above may be performed. Even in this case, effects other than those described in (2-2) above can be obtained.

In each embodiment, the second suppression process may be omitted.
In the first suppression process described above, the heater 55H is deenergized. Alternatively, the first suppression process may be a process in which the heater 55H is energized while the amount of power supplied to the heater 55H is reduced compared to when the first suppression process is not being executed. In this case, the heating of the heater 55H can be suppressed by executing the first suppression process.

- In the second suppression process described above, power to the detection element is stopped. Alternatively, the second suppression process may be a process in which power is supplied to the detection element while power is still supplied to the detection element, but the amount of power supplied to the detection element is reduced compared to when the second suppression process is not being executed. In this case, too, power supply to the detection element can be suppressed by executing the second suppression process, thereby lowering the ignition temperature of hydrogen gas.

- In the second embodiment, the internal combustion engine 10 is stopped after the sensor temperature THs becomes equal to or lower than the reference value THsref. Alternatively, if a stop request is made, the internal combustion engine 10 may be stopped and the first suppression process and second suppression process described above may be performed.

- The above-mentioned air-fuel ratio sensor 55 is an example of a sensor that is provided in the exhaust passage 90, 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 also be provided.

- A sensor with a heater that detects the air-fuel ratio is provided upstream of the catalyst 95, but a sensor with a heater that detects the air-fuel ratio may also be provided downstream of the catalyst 95, and the suppression process described above may also be performed on this downstream sensor.

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

The internal combustion engine 10 does not necessarily need to include the supercharger 24 or the ejector 40 .
The internal combustion engine 10 does not necessarily have to include the intake variable valve timing mechanism 85 and the exhaust variable valve timing mechanism 86 .

The control device 100 may execute both the processes shown in Fig. 2 and the processes shown in Fig. 3. Alternatively, the control device 100 may execute only one of the processes shown in Fig. 2 or 3.
The control device is not limited to a device equipped with a CPU 110 and memory 120 and executing software processing. For example, it may be equipped with a dedicated hardware circuit, such as an ASIC, that performs hardware processing on at least a portion of the software processing performed in the above embodiments. That is, the control device may have any of the following configurations (a) to (c): (a) 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) A processing device and program storage device that executes part of the above processing according to a program, and a dedicated hardware circuit that executes the remaining processing; or (c) A dedicated hardware circuit that executes all of the above processing. Here, the software execution device equipped with a processing device and program storage device, and the dedicated hardware circuit may be one or any multiple number.

<Related technical ideas>
The technical concepts that can be understood from the above embodiments and modifications will be described below.
(Appendix 1)
A control device applied to an internal combustion engine fueled by hydrogen,
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 to suppress heating of the heater when a specified condition is met under which the concentration of hydrogen gas flowing into the exhaust passage may become equal to or greater than a predetermined value.

(Appendix 2)
the specified condition is when the internal combustion engine is started,
2. The control device for an internal combustion engine according to claim 1, wherein the suppression process is executed from the start of the internal combustion engine until combustion of the air-fuel mixture becomes stable.

(Appendix 3)
the specified condition is when the operation of the internal combustion engine is stopped,
3. The control device for an internal combustion engine according to claim 1, wherein the suppression process is executed from when a request to stop operation of the internal combustion engine is made until the temperature of the sensor becomes equal to or lower than a predetermined temperature.

(Appendix 4)
4. The control device for an internal combustion engine according to claim 3, wherein a process is executed to delay stopping of the internal combustion engine from when the request to stop operation is made until the temperature of the sensor becomes equal to or lower than the predetermined temperature.

(Appendix 5)
A control device for an internal combustion engine as described in any one of appendices 1 to 4, wherein when the suppression process is a first suppression process, a second suppression process is executed to suppress the flow of electricity to a detection element provided in the sensor when the first suppression process is executed.

10...Internal combustion engine 19...Crankcase 20...Intake pipe 24...Supercharger 28...Throttle valve 29...Intake manifold 32...Suction passage 34...PCV valve 35...PCV passage 36...Bypass passage 37...Atmospheric air introduction passage 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...Wastegate valve (WGV)
100...Control device 110...Central processing unit (CPU)
120...Memory

Claims (3)

A control device applied to an internal combustion engine fueled by hydrogen,
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,
When a specified condition is met that indicates that the concentration of hydrogen gas flowing into the exhaust passage may be equal to or greater than a predetermined value, a suppression process is executed to suppress heating of the heater ;
the specified condition is when the operation of the internal combustion engine is stopped,
The suppression process is a process that is executed from when a request to stop the operation of the internal combustion engine is made until the temperature of the sensor falls to or below a predetermined temperature.
Control device for internal combustion engines. The control device for an internal combustion engine according to claim 1 , further comprising: a process for delaying the shutdown of the internal combustion engine from when the request to shut down the engine is made until the temperature of the sensor drops below the predetermined temperature. A control device applied to an internal combustion engine fueled by hydrogen,
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,
When a specified condition is met that indicates that the concentration of hydrogen gas flowing into the exhaust passage may be equal to or greater than a predetermined value, a suppression process is executed to suppress heating of the heater ;
When the suppression process is a first suppression process, a second suppression process is executed to suppress the supply of electricity to a detection element of the sensor when the first suppression process is executed.
Control device for internal combustion engines.