control device

Abstract

In an internal combustion engine, if the ignition timing is delayed, the temperature of exhaust gas rises, as a result, overheat of an exhaust system component is easily generated. In view of the above, the present application provides a control device of an internal combustion engine, the internal combustion engine being provided with: an ignition device; a changing device that changes the opening timing of an exhaust valve; an exhaust system component that is provided to an exhaust passage; and an injection device that injects fuel to supply fuel to the internal combustion engine, the control device, when a delay request amount of the ignition timing is acquired, executing the following processes: S105, a process of controlling the ignition device in such a manner that the delay amount of the ignition timing is equal to the delay request amount; and S104, a process of controlling the changing device in such a manner that the opening timing of the exhaust valve is delayed compared to when the delay request amount is acquired.

Description

Technical Field

[0001] This invention relates to a control device. Background Technology

[0002] The control device described in Patent Document 1 reduces the torque of the internal combustion engine by delaying the ignition timing when the automatic transmission shifts gears.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2024-055642 Summary of the Invention

[0004] If the ignition timing is delayed, the exhaust temperature will rise, which can easily lead to overheating of exhaust system components.

[0005] A control device for solving the above-mentioned problems is a control device for an internal combustion engine, wherein the internal combustion engine includes: an ignition device; a timing change device for changing the opening timing of an exhaust valve; an exhaust system component disposed in an exhaust passage; and an injection device for injecting fuel to supply fuel to the internal combustion engine. When the control device receives a delay request for ignition timing, it performs the following processes: a first delay process, controlling the ignition device such that the delay amount of ignition timing is equal to the delay request amount; and a second delay process, controlling the timing change device such that the opening timing of the exhaust valve is delayed compared to when the delay request amount is received.

[0006] Invention Effects

[0007] It is less likely to cause overheating of exhaust system components that are accompanied by ignition timing delay. Attached Figure Description

[0008] Figure 1 This is a diagram schematically illustrating the structure of one embodiment of the control device.

[0009] Figure 2 It means Figure 1 The flowchart shows the processing steps of the ignition timing delay process executed by the control device. Detailed Implementation

[0010] [About internal combustion engines]

[0011] refer to Figure 1 The structure of the internal combustion engine 20, which is controlled by the control device 10, will be described. The internal combustion engine 20 is mounted on the vehicle 100. The internal combustion engine 20 includes a cylinder 22, an intake passage 24, an exhaust passage 26, and an ignition device 28. Air flows into the cylinder 22 through the intake passage 24. The ignition device 28 ignites the air-fuel mixture flowing into the cylinder 22 by spark discharge. The combusted gases are discharged through the exhaust passage 26. The vehicle 100 may include a turbocharger including a turbine impeller disposed in the exhaust passage 26.

[0012] The intake passage 24 includes a throttle valve 30 that regulates the amount of air flowing within it, and an air flow meter 32 located downstream of the throttle valve 30. The air flow meter 32 detects the amount of air drawn in. In addition to detecting the amount of air drawn in, the air flow meter 32 also detects the intake air temperature. The intake passage 24 includes an intake port 34 connected to the cylinder 22. The exhaust passage 26 includes an exhaust port 36 connected to the cylinder 22.

[0013] The internal combustion engine 20 has an intake valve 38. When the intake valve 38 is open, the intake port 34 is connected to the cylinder 22. When the intake valve 38 is closed, the connection between the intake port 34 and the cylinder 22 is cut off. The internal combustion engine 20 also has an exhaust valve 40. When the exhaust valve 40 is open, the exhaust port 36 is connected to the cylinder 22. When the exhaust valve 40 is closed, the connection between the exhaust port 36 and the cylinder 22 is cut off. The intake valve 38 and the exhaust valve 40 open and close in conjunction with the rotation of the internal combustion engine 20.

[0014] The internal combustion engine 20 is equipped with an intake valve 38 changing device 42 for changing the opening and closing timing of the intake valve 38. The changing device 42 can continuously change the opening and closing timing of the intake valve 38 from the earliest timing to the latest timing based on the operating state of the internal combustion engine 20 (hereinafter referred to as the internal combustion engine operating state).

[0015] The operating states of the internal combustion engine include, for example, the engine speed (hereinafter referred to as engine speed), intake air volume, intake air temperature, and fuel injection quantity of the internal combustion engine 20. The earliest timing is the earliest timing within the range of the opening and closing timings of the intake valve 38 that can be changed via the changing device 42. The latest timing is the latest timing within the range of the opening and closing timings of the intake valve 38 that can be changed via the changing device 42.

[0016] The internal combustion engine 20 includes an exhaust valve 40 changing device 44 for changing the opening and closing timing of the exhaust valve 40. The changing device 44 can continuously change the opening and closing timing of the exhaust valve 40 from the earliest timing to the latest timing based on the operating state of the internal combustion engine. The earliest timing is the earliest timing within the range of opening and closing timings of the exhaust valve 40 that can be changed by the changing device 44. The latest timing is the latest timing within the range of opening and closing timings of the exhaust valve 40 that can be changed by the changing device 44.

[0017] The internal combustion engine 20 includes an exhaust system component 46. The exhaust system component 46 is disposed in the exhaust passage 26. The internal combustion engine 20 includes a catalyst device for purifying exhaust gas as the exhaust system component 46. The catalyst device is, for example, a three-way catalytic converter.

[0018] The internal combustion engine 20 includes an injection device 48. The injection device 48 injects fuel to supply fuel to the internal combustion engine 20. The injection device 48 includes an in-cylinder injection valve for injecting fuel into the cylinder 22 and a drive circuit for driving the in-cylinder injection valve. The injection device 48 may also include an intake port injection valve for injecting fuel into the intake port 34 and a drive circuit for driving the intake port injection valve.

[0019] The internal combustion engine 20 is equipped with various sensors. These sensors include, for example, a vehicle speed sensor 50 for detecting the vehicle speed 100, a throttle opening sensor 52 for detecting the amount of throttle operation, a speed sensor 54 for detecting the engine speed, a knock sensor 56 for detecting knocking in the cylinder 22, and a temperature sensor 58 for detecting the exhaust temperature in the exhaust passage 26.

[0020] The vehicle 100 is equipped with an automatic transmission 60 and a shift control device 62 for controlling the automatic transmission 60. The shift control device 62 controls the shift gears of the automatic transmission 60 based on the intake air volume, intake air temperature, vehicle 100 speed, throttle input, and internal combustion engine speed. The shift control device 62 outputs a signal determining the current shift gear to the control device 10.

[0021] When changing the shift gear of the automatic transmission 60, the shift control device 62 outputs a signal indicating that a shift is in progress to the control device 10, from the disengagement of the engagement element of the automatic transmission 60 corresponding to the previous shift gear until the engagement of the engagement element of the automatic transmission 60 corresponding to the new shift gear is completed. In one example, the control device 10 detects that the automatic transmission 60 is shifting based on this signal. The control device 10 may detect that the automatic transmission 60 is shifting based on any one of the following: the rate of change of internal combustion engine speed is above a predetermined value, a signal determining the current shift gear, or a loss of the ratio between internal combustion engine speed and vehicle speed.

[0022] [Regarding the control device]

[0023] Control device 10 controls ignition device 28, timing change device 44, and injection device 48. Control device 10 controls ignition device 28 to change ignition timing. Control device 10 controls timing change device 44 to change the opening timing of exhaust valve 40. Control device 10 controls injection device 48 to stop fuel supply to internal combustion engine 20 via fuel injection.

[0024] [Regarding ignition timing and knock]

[0025] The control unit 10 obtains the request amount for delaying ignition timing, i.e., the delay request amount, from the current ignition timing. The control unit 10 detects that the vehicle 100 is transitioning to an acceleration state based on an increase in throttle operation. Upon detecting that the vehicle 100 is transitioning to an acceleration state, the control unit 10 calculates and obtains the delay request amount based on the output values ​​of various sensors. When the control unit 10 receives a signal indicating that a gear shift is in progress from the shift control unit 62 of the automatic transmission 60, it also obtains the delay request amount in the same manner.

[0026] If the ignition timing is advanced, the torque produced by the internal combustion engine 20 increases. On the other hand, if the ignition timing is advanced, knocking is more likely to occur. The control device 10 determines the basic ignition timing based on the internal combustion engine speed, intake air volume, intake air temperature, etc. Within the range where knocking is not detected by the knock sensor 56, the control device 10 gradually advances the ignition timing from the basic ignition timing.

[0027] When the vehicle accelerates to 100 km / h, the combustion of fuel in cylinder 22 becomes unstable due to the rapid changes in intake air volume, internal combustion engine speed, and fuel injection quantity. If fuel combustion becomes unstable, the range of ignition timing that prevents knocking also changes. As a result, sometimes the ignition timing exceeds the range that prevents knocking and is advanced. Therefore, knocking is prone to occur when the vehicle accelerates to 100 km / h. To suppress knocking, the control device 10 delays the ignition timing when the vehicle accelerates to 100 km / h. Furthermore, when the automatic transmission 60 performs a gear shift, the torque of the internal combustion engine 20 is reduced to suppress the impact accompanying the shift. At this time, the control device 10 delays the ignition timing to achieve this torque reduction. The automatic transmission 60 shifting to achieve this torque reduction is, for example, an upshift.

[0028] [Regarding the opening timing of the exhaust valve]

[0029] The longer the opening timing of the exhaust valve 40 is delayed, the longer the exhaust gas remains in the cylinder 22. During this period, the heat from the exhaust gas is transferred to the inner circumferential surface of the cylinder 22. Therefore, the longer the opening timing of the exhaust valve 40 is delayed, the lower the exhaust temperature and the temperature of the exhaust system components 46.

[0030] On the other hand, delaying the opening timing of the exhaust valve 40 can easily lead to malfunctions. Examples of malfunctions include reduced intake air filling efficiency due to exhaust residue remaining in cylinder 22, and reduced filling efficiency due to a longer period during which the exhaust valve 40 and intake valve 38 open simultaneously. Furthermore, for example, in the case where the vehicle 100 is equipped with a turbocharger, reduced boosting efficiency is also an example of a malfunction.

[0031] [Regarding the temperature of exhaust system components]

[0032] The control device 10 estimates the temperature of the exhaust system component 46 based on the exhaust temperature and the operating state of the internal combustion engine. The control device 10 estimates the temperature of the exhaust system component 46 based on the output values ​​of various sensors. For example, the temperature of the exhaust system component 46 becomes higher when the exhaust temperature is high, when the intake air and fuel injection quantities are large, and when the ignition timing is delayed. Furthermore, for example, the more delayed the opening timing of the exhaust valve 40, the lower both the exhaust temperature and the temperature of the exhaust system component 46.

[0033] The control device 10 estimates the temperature rise of the exhaust system component 46 when the ignition timing is delayed based on the temperature of the exhaust system component 46 and the amount of ignition timing delay. For example, the temperature rise of the exhaust system component 46 becomes greater when the temperature of the exhaust system component 46 is low and when the amount of ignition timing delay is large.

[0034] [Regarding ignition timing delay handling]

[0035] refer to Figure 2 The steps of the ignition timing delay processing performed by the control device 10 will be explained.

[0036] If the control device 10 starts ignition delay timing processing, in step S101, it obtains the ignition timing delay request amount. Then, the control device 10 proceeds to step S102. Furthermore, in the following description, the ignition timing delay amount at which the ignition timing delay request amount is obtained is recorded as the ignition delay amount.

[0037] In step S102, the control device 10 determines whether the requested delay amount is below the first allowable delay capacity. The first allowable delay capacity is the upper limit of the ignition delay amount within the temperature range of the exhaust system component 46, provided that the temperature does not exceed the allowable temperature value. If the requested delay amount exceeds the first allowable delay capacity, and the ignition delay amount is set to be equal to the requested delay amount, the temperature of the exhaust system component 46 is likely to exceed the allowable temperature value. The allowable temperature value is, for example, the temperature at which the degree of damage or deterioration of the exhaust system component 46 increases due to the temperature rise. A large degree of damage or deterioration of the exhaust system component 46 means that the reduction in the required function of the exhaust system component 46 is so large as to be non-negligible. For example, in the case where the exhaust system component 46 is a three-way catalytic converter, the allowable temperature value is the temperature at which the degree of deterioration of the three-way catalytic converter increases.

[0038] If the delay request amount is determined to be below the first allowable delay capacity, the control device 10 will proceed to step S105 (S102: Yes). If the delay request amount is determined to be above the first allowable delay capacity, the control device 10 will proceed to step S103 (S102: No).

[0039] In step S103, the control device 10 determines whether the delay request amount is below the second delay allowable capacity. The second delay allowable capacity is greater than the first delay allowable capacity. The second delay allowable capacity is the upper limit of the ignition delay amount when the temperature of the exhaust system component 46 is within the temperature allowable range, and the ignition timing is delayed to the latest possible timing by delaying the opening timing of the exhaust valve 40. The first and second delay allowable capacities referenced by the control device 10 when the vehicle 100 accelerates may be the same as or different from the first and second delay allowable capacities referenced by the control device 10 when the automatic transmission 60 shifts gears.

[0040] If the delay request amount is determined to be below the second allowable delay capacity, the control device 10 proceeds to step S104 (S103: Yes). If the delay request amount is determined to exceed the second allowable delay capacity, the control device 10 proceeds to step S106 (S103: No). Steps S102 and S103 are examples of determination processes.

[0041] In step S104, the control device 10 performs a second delay process. The second delay process controls the processing of the changing device 44 by delaying the opening timing of the exhaust valve 40 compared to the delay request amount obtained in step S101. The second delay process delays the opening timing of the exhaust valve 40 to the latest possible timing. Then, the control device 10 proceeds to step S105.

[0042] In step S105, the control device 10 performs a first delay process. The first delay process is to control the ignition device 28 such that the ignition delay amount from when the delay request amount is obtained in step S101 is equal to the delay request amount. The processing of step S105 is performed in the following cases: if it is determined in step S102 that the delay request amount is below the first delay allowable capacity, or if it is determined in step S103 that the delay request amount is below the first delay allowable capacity, the opening timing of the exhaust valve 40 is delayed to the latest timing in step S104. Therefore, when the ignition device 28 is controlled such that the ignition delay amount is equal to the delay request amount, the temperature of the exhaust system component 46 is less likely to exceed the temperature allowable value.

[0043] In step S106, the control device 10 performs a fuel cut-off process. The fuel cut-off process involves controlling the injection device 48 to stop fuel injection. In step S103, if it is determined that the delay request exceeds the second allowable delay capacity, the control device 10 determines that it is impossible to simultaneously ensure that the temperature of the exhaust system component 46 does not exceed the allowable temperature value and delay the ignition timing to the delay request amount, and thus performs the fuel cut-off process. By performing the fuel cut-off process, the temperature rise of the exhaust system component 46 and knocking will not occur.

[0044] However, when fuel cut-off is performed, it can easily lead to a deterioration in driving performance. For example, the reduced acceleration performance after the restart of fuel injection, the instability of combustion after the restart of fuel injection, and the increased vibration of the internal combustion engine 20 caused by this combustion instability are all causes of the deterioration in driving performance.

[0045] The ignition timing delay processing is completed by completing either step S105 or step S106. In summary, when the control device 10 determines that the delay request amount is below the first allowable delay capacity, it performs the first delay processing. When the control device 10 determines that the delay request amount exceeds the first allowable delay capacity but is below the second allowable delay capacity, it performs both the first and second delay processing. When the control device 10 determines that the delay request amount exceeds the second allowable delay capacity, it performs fuel cut-off processing.

[0046] <Effects of this implementation method>

[0047] The control device 10 of this embodiment has the following effects.

[0048] (1) The control device 10 performs the second delay process together with the first delay process. By performing the second delay process, it is less likely to cause overheating of the exhaust system component 46 when the ignition timing is delayed in the first delay process.

[0049] (2) When the control device 10 determines that the delay request amount is below the delay allowable capacity, it does not perform the second delay processing. Therefore, the aforementioned faults that accompany the execution of the second delay processing are less likely to occur.

[0050] (3) In the second delay process, the control device 10 delays the opening timing of the exhaust valve 40 to the latest timing. Compared with the case where the opening timing of the exhaust valve 40 is delayed to an earlier timing than the latest timing, the exhaust temperature decreases, and therefore the temperature rise of the exhaust system component 46 is less likely to occur.

[0051] (4) When the control device 10 determines that the delay request exceeds the first delay allowable capacity and is below the second delay allowable capacity, it performs the first delay processing and the second delay processing. Therefore, compared with the case where the control device 10 performs fuel cut-off processing when the first delay allowable capacity is exceeded, it is less likely to cause a deterioration in driving performance.

[0052] <Example of Change>

[0053] The above-described embodiments can be implemented with the following modifications. The above-described embodiments and the following modifications can be combined with each other to implement them within the scope of technical inconsistency.

[0054] • A structure including multiple exhaust system components 46 can be adopted. The multiple exhaust system components 46 are, for example, a catalyst device, a filter for capturing particulate matter contained in the exhaust, a temperature sensor 58, and at least two of the turbine impellers of the turbocharger if the vehicle 100 is equipped with a turbocharger.

[0055] In this structure, both the first and second allowable delay capacities are determined based on the degree of damage or degradation of the component most severely affected by the ignition timing delay among multiple components. The respective degree of damage or degradation of the multiple exhaust system components 46 can be determined based on the component's temperature and the temperature rise during the first delay treatment or during both the first and second delay treatments. The components referenced when determining the first and second allowable delay capacities can be the same or different components.

[0056] Therefore, according to the above structure, when the allowable delay capacity is less than or equal to the first allowable delay capacity, even if the first delay process is performed, it is unlikely that any one of the multiple exhaust system components 46 will suffer significant damage or deterioration. Furthermore, when the allowable delay capacity exceeds the first allowable delay capacity but is less than or equal to the second allowable delay capacity, if the second delay process is performed together with the first delay process, it is also unlikely that any one of the multiple exhaust system components 46 will suffer significant damage or deterioration.

[0057] • The control device 10 can perform control that omits the determination in step S102. In this case, after performing the acquisition process in step S101, the control device 10 proceeds to step S103. The processing after step S103 is performed in the same manner as in the embodiment.

[0058] • The control device 10 may not be able to change the closing timing of the exhaust valve 40. The control device 10 only needs to be able to delay the opening timing of the exhaust valve 40.

[0059] • In the second delay process, the opening timing of the exhaust valve 40 can be delayed to an earlier time than the latest possible time. In this case, the opening timing of the exhaust valve 40 can be set earlier during the execution of the first delay process, provided that the temperature of the exhaust system component 46 does not exceed the allowable temperature value. As a result, malfunctions accompanying the execution of the second delay process are less likely to occur.

[0060] The control device 10 can delay ignition timing during downshifting of the automatic transmission 60. During downshifting, fuel cut-off is performed, thus minimizing shock. However, in cases of forced downshifting by significantly depressing the accelerator pedal, fuel injection is performed, which can easily cause shock.

[0061] Symbol Explanation

[0062] 10-Control device, 20-Internal combustion engine, 22-Cylinder, 24-Intake passage, 26-Exhaust passage, 28-Ignition device, 30-Throttle valve, 32-Air flow meter, 34-Intake port, 36-Exhaust port, 38-Intake valve, 40-Exhaust valve, 42-Change device, 44-Change device, 46-Exhaust system component, 48-Injection device, 50-Vehicle speed sensor, 52-Throttle opening sensor, 54-Speed ​​sensor, 56-Knock sensor, 58-Temperature sensor, 60-Automatic transmission, 62-Shift control device, 100-Vehicle.

Claims

1. A control device for an internal combustion engine, characterized in that, The internal combustion engine includes: an ignition device; a timing device for changing the opening timing of an exhaust valve; exhaust system components disposed in an exhaust passage; and an injection device for injecting fuel to supply fuel to the internal combustion engine. When the control device receives the ignition timing delay request, it performs the following processing: The first delay process controls the ignition device such that the delay amount of the ignition timing is equal to the delay request amount; and The second delay processing controls the alteration device by delaying the acquisition of the delay request amount based on the valve opening timing ratio of the exhaust valve.

2. The control device according to claim 1, characterized in that, The control device performs the following processing: Upon obtaining the delay request amount, a determination process is performed to determine whether the delay request amount exceeds the allowable delay capacity. When it is determined that the amount of the delay request is below the allowable delay capacity, the first delay processing is performed; and When it is determined that the amount of delay requests exceeds the allowable delay capacity, the first delay processing and the second delay processing are performed.

3. The control device according to claim 1, characterized in that, The second delay process involves delaying the opening timing of the exhaust valve to the latest timing within the range that can be changed by the changing device. The control device performs the following processing: Upon obtaining the delay request amount, a determination process is performed to determine whether the delay request amount exceeds the allowable delay capacity. When it is determined that the delay request amount is below the delay allowable capacity, the first delay processing and the second delay processing are performed; and When it is determined that the delay request exceeds the delay allowable capacity, a fuel cut-off process is performed to control the injection device by stopping fuel injection.

4. The control device according to claim 1, characterized in that, The second delay process involves delaying the opening timing of the exhaust valve to the latest timing within the range that can be changed by the changing device. The control device performs the following processing: When the delay request amount is obtained, a determination process is performed to determine whether the delay request amount exceeds the first delay allowable capacity and whether the delay request amount exceeds the second delay allowable capacity, which is larger than the first delay allowable capacity. When it is determined that the amount of the delay request is below the first delay allowable capacity, the first delay processing is performed; When it is determined that the delay request amount exceeds the first delay allowable capacity and is below the second delay allowable capacity, the first delay processing and the second delay processing are performed; and When it is determined that the delay request exceeds the second delay allowable capacity, a fuel cut-off process is performed to control the injection device by stopping fuel injection.

5. The control device according to any one of claims 1 to 4, characterized in that, The internal combustion engine is installed in a vehicle equipped with an automatic transmission. The control device acquires the delay request amount when at least one of the vehicle's acceleration and the automatic transmission's shifting is performed.

Images