Control device for internal combustion engine

Abstract

The invention provides a control device for an internal combustion engine. The leak determination process determines the presence or absence of a fuel leak from a fuel supply system on the condition that a start switch of an internal combustion engine has completed an ON operation. The start-up estimation process estimates the presence or absence of the possibility of a start-up operation before the start-up switch is turned on. The processing circuit does not execute the fuel injection based on the fuel injection process when the leakage determination process is not completed even if the start switch has completed the ON operation. Even if the start switch is not turned on, when the start estimation process estimates that there is a possibility of a start operation, the processing circuit starts the leakage determination process.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority from Japanese patent application No. 2024-024496, filed on February 21, 2024, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates to a control device for an internal combustion engine. Background Art

[0004] Japanese Patent Application Laid-Open No. 2006-250141 discloses a control device for an internal combustion engine that detects the presence or absence of fuel leakage. Summary of the Invention

[0005] Problems to be solved by the invention

[0006] There is room for shortening the time from when the starter switch is turned on to when the fuel is injected.

[0007] Technical means to solve problems

[0008] According to one aspect of the present disclosure, a control device for an internal combustion engine is provided. The internal combustion engine is mounted on a vehicle. The control device includes a processing circuit. The processing circuit is configured to execute: a fuel injection process for executing fuel injection by a fuel injection valve of the internal combustion engine, conditional on the starter switch of the internal combustion engine being turned on; a leakage determination process for determining whether there is fuel leakage from a fuel supply system of the internal combustion engine, conditional on the starter switch being turned on; and a start estimation process for estimating whether there is a possibility of a start operation before the starter switch is turned on. The possibility of a start operation is the possibility of the starter switch being turned on. The processing circuit is configured not to execute fuel injection based on the fuel injection process if the leakage determination process is not completed even if the starter switch is turned on. The processing circuit is configured to start the leakage determination process even if the starter switch is not turned on, if the start estimation process estimates that there is a possibility of a start operation.

[0009] According to the above configuration, the control device also initiates the leak determination process when it has estimated that a start operation is possible. In this case, the leak determination process is completed earlier than, for example, when the leak determination process is initiated after the start switch has been turned on. This shortens the time from turning on the start switch to fuel injection.

[0010] For example, the control device can initiate the determination of fuel leakage from the fuel supply system upon turning on the starter switch. This leakage determination method can be applied to an internal combustion engine in which fuel injection from a fuel injection valve is performed under the condition that there is no fuel leakage. In this case, the time from turning on the starter switch to fuel injection becomes longer. The above configuration mitigates this possibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a schematic diagram showing the overall structure of an internal combustion engine according to one embodiment.

[0012] Figure 2 It shows Figure 1 Flowchart of the steps of the process performed by the control device shown.

[0013] Figure 3 : is a timing chart showing the relationship between the timing of turning on the start switch and the timing of starting the leakage determination process. DETAILED DESCRIPTION

[0014] In this specification, “at least one of A and B” should be understood to mean “only A”, “only B” or “both A and B”.

[0015] Below, refer to Figures 1 to 3 , an embodiment of a control device for an internal combustion engine is described.

[0016] <Internal combustion engine and control device>

[0017] Figure 1 The internal combustion engine 10 shown operates using hydrogen as fuel. The internal combustion engine 10 is mounted on a vehicle 200. Hereinafter, hydrogen may be referred to as fuel.

[0018] The internal combustion engine 10 includes a fuel supply system 10 a , which includes a tank 20 , a first shutoff valve 21 , a second shutoff valve 22 , a pressure reducing valve 30 , a fuel pipe 41 , a delivery pipe 42 , and a plurality of fuel injection valves 52 .

[0019] The tank 20 stores fuel in a compressed state. The fuel pipe 41 is a fuel passage through which the fuel flows. The fuel pipe 41 connects the tank 20 to a delivery pipe 42. The delivery pipe 42 is connected to each fuel injection valve 52.

[0020] The fuel stored in the tank 20 is supplied to each fuel injection valve 52 via the fuel pipe 41 and the delivery pipe 42. The fuel injection valve 52 injects fuel into the cylinder 51 of the internal combustion engine 10.

[0021] The first shutoff valve 21 , the pressure reducing valve 30 , and the second shutoff valve 22 are arranged in this order in the fuel pipe 41 along the direction of fuel flowing from the tank 20 to the fuel injection valve 52 .

[0022] The first shutoff valve 21 is disposed near the outlet of the tank 20. When the first shutoff valve 21 is open, fuel is supplied from the tank 20 to the fuel pipe 41. When the first shutoff valve 21 is closed, the supply of fuel from the tank 20 to the fuel pipe 41 is stopped.

[0023] The pressure reducing valve 30 adjusts the pressure of the fuel supplied to the fuel injection valve 52 to a pressure according to the operating state of the internal combustion engine 10 .

[0024] The second shutoff valve 22 is disposed near the delivery pipe 42. When the second shutoff valve 22 is open, fuel is supplied from the fuel pipe 41 to the delivery pipe 42. When the second shutoff valve 22 is closed, the supply of fuel from the fuel pipe 41 to the delivery pipe 42 is stopped.

[0025] When the internal combustion engine 10 is stopped, both the first shutoff valve 21 and the second shutoff valve 22 are closed. On the other hand, when the internal combustion engine 10 is operating, both the first shutoff valve 21 and the second shutoff valve 22 are open.

[0026] The control unit 100 of the internal combustion engine 10 includes a CPU 110 and a memory 120, which includes ROM and RAM. The control unit 100 performs various processes by having the CPU 110 execute programs stored in the memory 120. The control unit 100 corresponds to a control circuit. The CPU 110 corresponds to a processing circuit. The memory 120 corresponds to a non-transitory storage medium. Some or all of the components of the control unit 100 may be implemented using hardware (including circuitry) such as an LSI (Large Scale Integration), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a GPU (Graphics Processing Unit), or through the coordinated use of software and hardware. The control unit 100 constitutes the control device of the internal combustion engine 10.

[0027] The control unit 100 , the pressure sensor 81 , the first to third hydrogen sensors 91 - 93 , the start switch 70 , the door switch 71 , the lock sensor 72 , the seat sensor 73 , and the buckle sensor 74 are examples of a plurality of components constituting the control system of the internal combustion engine 10 .

[0028] <Various Sensors>

[0029] A pressure sensor 81 is provided in a portion of the fuel pipe 41 between the pressure reducing valve 30 and the second shutoff valve 22. The pressure sensor 81 outputs a signal corresponding to the fuel pressure P1 of the fuel supply system 10a.

[0030] A first hydrogen sensor 91 is provided near the tank 20 . The first hydrogen sensor 91 outputs a signal corresponding to a first hydrogen concentration H1 . The first hydrogen concentration H1 is the hydrogen concentration near the tank 20 .

[0031] A second hydrogen sensor 92 is provided near the portion of the fuel pipe 41 between the pressure reducing valve 30 and the second shutoff valve 22. The second hydrogen sensor 92 outputs a signal corresponding to a second hydrogen concentration H2. The second hydrogen concentration H2 is the hydrogen concentration near the portion of the fuel pipe 41 between the pressure reducing valve 30 and the second shutoff valve 22.

[0032] A third hydrogen sensor 93 is provided near the delivery pipe 42. The third hydrogen sensor 93 outputs a signal corresponding to a third hydrogen concentration H3. The third hydrogen concentration H3 is the hydrogen concentration near the delivery pipe 42.

[0033] The controller 100 controls the fuel injection valve 52 to inject fuel into the cylinder 51. The controller 100 detects the fuel pressure P1 based on the output signal of the pressure sensor 81. The controller 100 detects the hydrogen concentration based on the output signals of the first to third hydrogen sensors 91 to 93.

[0034] The control unit 100 and pressure sensor 81 are examples of a specific embodiment of a pressure detection device that detects the pressure of the fuel supply system 10a. The control unit 100 and the first to third hydrogen sensors 91-93 are examples of a specific embodiment of a concentration detection device that detects hydrogen concentration. The concentration detection device is an example of a leak detection device that detects fuel leaks. The leak detection device does not necessarily need to detect fuel leaks from the fuel injection valve 52 into the cylinder 51.

[0035] Vehicle 200 has a door opening and closing switch 71 that detects the open and closed state of the boarding door 61. Vehicle 200 has a lock sensor 72. The lock sensor 72 detects that the locking mechanism 62 of the boarding door 61 of vehicle 200 has changed from a locked state to an unlocked state. Vehicle 200 has a seat sensor 73. The seat sensor 73 detects whether an occupant is seated on the seat 63 of vehicle 200. Vehicle 200 has a buckle sensor 74. The buckle sensor 74 detects whether the tongue of the seat belt of vehicle 200 is in a state of being inserted into the buckle 64. The open and closed state of the boarding door 61 is equivalent to the device state of an on-board device such as the boarding door 61. For example, the open state of the boarding door 61 is a first state. The closed state of the boarding door 61 is a second state. The first state is different from the second state. For example, the locked state of the locking mechanism 62 is the first state. The unlocked state of the locking mechanism 62 is the second state.

[0036] <Processing Executed by the Control Unit>

[0037] The control unit 100 executes a fuel injection process. The fuel injection process executes fuel injection from the fuel injection valve 52 on the condition that the start switch 70 of the internal combustion engine 10 has been turned on.

[0038] The control unit 100 performs a start estimation process before the start switch 70 is turned on. Here, the start preparation period is the period from the opening operation of the boarding door 61 to the turning on operation of the start switch 70. For example, the start preparation period corresponds to the period from the time when the passenger enters the vehicle 200 by opening the boarding door 61 to the time when the start switch 70 is turned on. The start estimation process estimates whether there is a possibility of a start operation during the start preparation period. The possibility of a start operation is the possibility of turning on the start switch 70 in order to start the internal combustion engine 10. The possibility of a start operation is also the possibility of starting the internal combustion engine. The opening operation of the boarding door 61 may also include the release operation of the locking mechanism 62 of the boarding door 61. For example, after releasing the locking mechanism 62, the passenger opens the boarding door 61 and enters the vehicle 200.

[0039] The control unit 100 detects the following [1] to [4] based on the output signals of the lock sensor 72 , the door opening and closing switch 71 , the seat occupancy sensor 73 , and the buckle sensor 74 .

[0040] [1] The locking mechanism 62 is released from locking the boarding door 61;

[0041] [2] The boarding and alighting door 61 is opened;

[0042] [3] The seat 63 of the vehicle 200 changes to a state in which the seat 63 supports the occupant; and

[0043] [4] The seat belt of the vehicle 200 changes to a state where the occupant is restrained.

[0044] If the control unit 100 detects at least one of [1] to [4] during the start preparation period, it infers that a start operation is possible. Vehicle 200 may not include lock sensor 72. In this case, the control unit 100 may detect that the door 61 has been unlocked based on the control unit 100 outputting a signal for unlocking to the locking mechanism 62.

[0045] The control unit 100 performs a leak determination process to determine whether there is a fuel leak from the fuel supply system 10a. Specifically, when the leak determination process begins, the control unit 100 turns on a fuel cutoff flag for stopping fuel injection and switches on the first to third hydrogen sensors 91 to 93. During the leak determination process, the control unit 100 determines whether there is a fuel leak by referring to the first to third hydrogen concentrations H1 to H3. Specifically, if the first to third hydrogen concentrations H1 to H3 are all below a predetermined value HL, the control unit 100 determines that no fuel leak has occurred. If any of the first to third hydrogen concentrations H1 to H3 exceeds the predetermined value HL, the control unit 100 determines that a fuel leak has occurred.

[0046] Reference Figure 2 , the flow of the fuel injection process, the start estimation process, and the leakage determination process executed by the control unit 100 will be described.

[0047] like Figure 2 As shown, if the start switch 70 is turned on (S100: Yes), the control unit 100 executes the leakage determination process (S120-S150). If the start switch 70 is not turned on (S100: No), the control unit 100 executes the start estimation process (S110). Even if the start switch 70 is not turned on (S100: No), the control unit 100 starts the leakage determination process (S120-S150) if the start estimation process estimates that the start switch 70 may have been turned on (S110: Yes). The start operation possibility refers to the possibility that the start switch 70 has been turned on.

[0048] When the control unit 100 begins the leak determination process, it sets the fuel cutoff flag to on (S120). The control unit 100 measures the time that has elapsed since the start of the leak determination process. The control unit 100 determines whether the elapsed time has reached a predetermined response time (S130). If the elapsed time has reached the predetermined response time (S130: Yes), the control unit 100 determines whether a fuel leak has occurred (S140). If no fuel leak has occurred (S140: Yes), the control unit 100 changes the fuel cutoff flag from on to off (S150). As a result, fuel injection can be performed according to the fuel injection process (S160, S170). Specifically, when the starter switch 70 is on (S160: Yes), the control unit 100 performs fuel injection (S170). Even if the starter switch 70 has been turned on, the control unit 100 does not perform fuel injection according to the fuel injection process until the leak determination process is complete. When the control unit 100 determines that a fuel leak has occurred ( S140 : NO), the control unit 100 continues to keep the fuel cut flag on, and therefore does not perform fuel injection.

[0049] There may be a response delay between the time the first through third hydrogen sensors 91 through 93 are turned on and the time they output detection values ​​corresponding to the hydrogen concentrations around them. This response delay can take, for example, several seconds to several tens of seconds. The predetermined response time corresponds to this response delay.

[0050] <Function of this embodiment>

[0051] Figure 3 The solid line indicates a state in which there is no abnormality, that is, no hydrogen leakage, in this embodiment. Figure 3 When the leak determination process is initiated at timing t1, the time counter value increments from timing t1. As a prerequisite for initiating the leak determination process, the possibility of a start operation is inferred. The possibility of a start operation refers to the possibility of turning on the start switch 70. The time counter value increments based on the elapsed time since the leak determination process began. At timing t3, when the time counter value reaches a predetermined value C1, if none of the first to third hydrogen concentrations H1 to H3 exceeds the predetermined value HL, the fuel cutoff flag switches from on to off. The predetermined value C1 is used to determine whether the elapsed time has reached the predetermined response time.

[0052] When the fuel cut flag is switched off, fuel injection can be performed when the start switch 70 is turned on. Figure 3The dashed line indicates an abnormality, i.e., hydrogen leakage, in this embodiment. As shown by the dashed line, at time t3, if any of the first to third hydrogen concentrations H1 to H3 exceeds the specified value HL, the fuel cutoff flag remains on. Therefore, fuel injection is not performed.

[0053] Comparative example in Figure 3 At the timing t2, the leakage determination process starts. At the timing t2, the start switch 70 has completed the on operation. Figure 3 The dashed line indicates the normal state of the comparative example. In the comparative example, as indicated by the dashed line, the time counter value reaches the predetermined value C1 at timing t4. Therefore, in the comparative example, even if the start switch 70 is turned on at timing t1, fuel injection cannot be performed before timing t4. Figure 3 The time period T1 shown is the time period between timing t3 and timing t4. That is, in the comparative example, the start of fuel injection is delayed by the amount of time period T1 compared to the present embodiment. On the other hand, in the present embodiment, the leak determination process can be started at timing t1 when the possibility of a starting operation is estimated. Therefore, the present embodiment can start fuel injection at timing t3, after a predetermined response time has elapsed from timing t1.

[0054] <Effects of this embodiment>

[0055] This embodiment achieves the following effects.

[0056] (1) The control unit 100 of the internal combustion engine 10 can Figure 3 The time from when the start switch 70 is turned on at timing t2 shown to when fuel injection by the fuel injection valve 52 becomes possible is shortened. Figure 3 The amount of time period T1 is shown.

[0057] (2) The vehicle 200 has an on-board device having a device state that switches between two different states during a start preparation period. Here, the on-board device has a device state that switches between a first state and a second state. The second state is different from the first state. The start preparation period is the period from the opening operation of the boarding door 61 to the turning-on operation of the start switch 70. The opening operation of the boarding door 61 may also include the release operation of the locking mechanism 62 of the boarding door 61. The start estimation process estimates that there is a possibility of a start operation based on the detection of the switching of the device state of the on-board device. The start operation possibility is the possibility of performing the turning-on operation of the start switch 70. When the device state of the on-board device switches, the possibility of the start operation following the switching is relatively high. The start operation possibility is the possibility of the turning-on operation of the start switch 70. Therefore, according to the above structure, the estimation accuracy of the start estimation process is high.

[0058] (3) The vehicle 200's entry and exit doors 61, locking mechanism 62, seats 63, and seat belts are all onboard devices that have device states that switch between two different states during the start preparation period. These onboard devices are examples of onboard devices essential to the vehicle 200. Therefore, the start estimation process can be executed based on the device states of the essential onboard devices of the vehicle 200.

[0059] (4) The internal combustion engine 10 is equipped with a leak detection device that detects the hydrogen concentration. When fuel leaks from the fuel supply system 10a, the hydrogen concentration detected by the control unit 100 becomes high. Therefore, the leak determination process has high accuracy.

[0060] (5) The leak detection device requires a predetermined response time to detect a fuel leak. The leak detection device measures the elapsed time from the start of the leak determination process. The leak detection device detects a fuel leak based on the hydrogen concentration when the elapsed time reaches the predetermined response time. Therefore, the leak determination process achieves high accuracy.

[0061] <Change Example>

[0062] This embodiment can be implemented by modifying as follows: This embodiment and the following modifications can be implemented in combination with each other within a range that does not technically conflict.

[0063] The start estimation process may acquire the time when the start switch 70 is turned on multiple times. The start estimation process may estimate that there is a possibility of a start operation at a time before a time period in which the start switch 70 is turned on with high frequency.

[0064] When the vehicle 200 is equipped with an electronic key system, the steps of the start estimation process may be changed as follows. The electronic key system includes a vehicle ECU as the ECU of the vehicle 200. The vehicle ECU wirelessly communicates with an electronic key located near the vehicle 200. When the vehicle ECU authenticates that the electronic key is a legitimate one, it allows the locking mechanism 62 of the boarding and alighting door 61 to be released. A legitimate electronic key can release the locking mechanism 62 of the boarding and alighting door 61. In this case, the start estimation process may also infer that there is a possibility of a start operation when the electronic key system authenticates that the electronic key is legitimate. The possibility of a start operation is the possibility that the start switch 70 has been turned on.

[0065] For example, a camera that captures the interior of the vehicle, an ultrasonic sensor installed in the vehicle, or the like can detect that a passenger has entered the vehicle. When such a detection is performed, the start estimation process can also estimate that there is a possibility of a start operation.

[0066] The above embodiments and variations illustrate multiple detection events as the basis for the startup estimation process to estimate the possibility of a startup operation. The control unit 100 may also be configured to detect at least one of these multiple detection events. The startup estimation process may estimate the possibility of a startup operation upon detecting any one of these multiple detection events. The startup estimation process may also estimate the possibility of a startup operation upon detecting two or more detection events.

[0067] The leak detection device for detecting fuel leaks may also be a pressure detection device. For example, when the control unit 100 begins the leak determination process, it closes the fuel injection valve 52. The control unit 100 then opens the first shutoff valve 21, the second shutoff valve 22, and the pressure reducing valve 30. Based on the output signal of the pressure sensor 81, the control unit 100 detects changes in the fuel pressure P1 of the fuel supply system 10a since the start of the leak determination process. Upon detecting a decrease in the fuel pressure P1 of the fuel supply system 10a, the control unit 100 determines that a fuel leak has occurred.

[0068] For example, the control unit 100 measures the elapsed time from the start of the leak determination process. The control unit 100 may detect the fuel pressure P1 when the elapsed time reaches a predetermined response time, or may detect the decrease in fuel pressure P1. If the fuel pressure P1 is less than a predetermined pressure value, or if the decrease in fuel pressure P1 exceeds a predetermined decrease, the control unit 100 determines that a fuel leak has occurred. If a fuel leak occurs, there may be a response delay in the decrease in fuel pressure P1 after the start of the leak determination process. The predetermined response time corresponds to this response delay.

[0069] The control unit 100 may also determine that a fuel leak has occurred when the fuel pressure P1 after the start of the leakage determination process drops to atmospheric pressure, or drops to a pressure value considered atmospheric pressure. The control unit 100 may also determine that a fuel leak has occurred when the rate of change of the fuel pressure P1 after the start of the leakage determination process is greater than a predetermined rate of change.

[0070] Fuel leakage may be detected based on the detection results of both the pressure detection device and the concentration detection device.

[0071] The placement and number of hydrogen sensors are arbitrary, as long as they can detect hydrogen concentration changes due to fuel leakage. The placement and number of pressure sensors are arbitrary, as long as they can detect the pressure of the fuel supply system 10a changes due to fuel leakage.

[0072] The control unit 100 may determine that there is a hydrogen leak based on the fact that the output signal of the hydrogen sensor converges to a value indicating a fuel leak after the leakage determination process starts.

[0073] The number of control devices that execute multiple processes, including fuel injection, leak determination, startup estimation, hydrogen concentration detection, and hydrogen pressure detection, is arbitrary. For example, multiple control devices may execute these processes. For example, one control device may execute a portion of the multiple processes, while other control devices execute the remaining processes. For example, multiple control devices may collaboratively execute a single process.

[0074] The fuel is not limited to hydrogen. For example, the fuel may be natural gas, propane gas, gasoline, light oil, or a mixture thereof. The internal combustion engine 10 may be operated by two or more fuels.

[0075] As used in this specification, the expression "at least one" refers to "one or more" of the desired options. For example, if there are two options, the expression "at least one" refers to "only one option" or "both options." As another example, if there are three or more options, the expression "at least one" refers to "only one option" or "a combination of two or more options."

[0076] For example, the control device may also include a dedicated hardware circuit, such as an ASIC, that performs hardware processing for at least a portion of the processing performed by software in the above-mentioned embodiments. In other words, the control device may be any of the following structures (a) to (c). (a) A processor that performs all of the above-mentioned processing according to a program and a program storage device such as a ROM that stores the program (including non-transitory computer-readable storage media). (b) A processor that performs part of the above-mentioned processing according to a program, a program storage device, and a dedicated hardware circuit that performs the remaining processing. (c) A dedicated hardware circuit that performs all of the above-mentioned processing. Here, the software execution device including the processor and the program storage device and the dedicated hardware circuit may be one or any number of them.

Claims

1. A control device for an internal combustion engine, wherein: The internal combustion engine is mounted on a vehicle, and the control device includes a processing circuit. The processing circuit is configured to perform: a fuel injection process for executing fuel injection by a fuel injection valve of the internal combustion engine on the condition that a start switch of the internal combustion engine has been turned on; a leakage determination process for determining whether there is a fuel leak from the fuel supply system of the internal combustion engine, on the condition that the start switch has been turned on; as well as a start estimation process of estimating whether or not a start operation is possible before the start switch is turned on, wherein the start operation possibility is a possibility that the start switch is turned on; The processing circuit is configured to not execute the fuel injection based on the fuel injection process when the leakage determination process is not completed even if the start switch is turned on. The processing circuit is configured to start the leakage determination process when the start estimation process estimates that there is a possibility of the start operation even if the start switch has not been turned on.

2. The control device for an internal combustion engine according to claim 1, The vehicle is equipped with a boarding and alighting door and onboard equipment. The start preparation period is the period from the opening operation of the boarding and alighting doors to the turning-on operation of the start switch. The in-vehicle device has a device state that switches between a first state and a second state during the startup preparation period, the second state being different from the first state. The startup estimation process estimates that the startup operation is possible based on detection of switching of the device state.

3. The control device for an internal combustion engine according to claim 1, The start estimation process estimates that the start operation possibility exists based on detection of at least one of the following situations: The boarding and alighting door is opened; The seat of the vehicle is changed into a state of supporting an occupant; and The seat belt of the vehicle is changed to a state of restraining the occupant.

4. The control device for an internal combustion engine according to claim 1, The vehicle is equipped with a concentration detection device for detecting hydrogen concentration. The fuel injection valve is configured to inject hydrogen as fuel. The leakage determination process determines the fuel leakage from the fuel supply system based on the hydrogen concentration detected by the concentration detection device.

5. The control device for an internal combustion engine according to claim 4, The leakage determination process determines whether or not there is a hydrogen leak based on the hydrogen concentration detected by the concentration detection device when an elapsed time from the start of the leakage determination process reaches a predetermined response time.

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