EGR valve control device

Abstract

An EGR valve control device (100) is provided with: an EGR valve (9) for adjusting the exhaust gas recirculation amount of an internal combustion engine (1) mounted in a vehicle; a detection unit (9a) that detects a nip state in which foreign matter is nipped into the EGR valve (9); and a control unit (10) that controls the EGR valve (9). When the rotation of the internal combustion engine (1) is stopped while the ignition switch of the vehicle is turned on, the control unit (10) controls the EGR valve (9) to perform an opening / closing operation for a predetermined number of times on the condition that the engagement state is detected by the detection unit (9a).

Description

Technical Field

[0001] The present invention relates to an EGR valve control device that controls an EGR (Exhaust Gas Recirculation) valve of an internal combustion engine mounted on a vehicle. Background Art

[0002] In recent years, for vehicles equipped with an EGR valve, research and development have been carried out to contribute to the sustainable development of the transportation system by ensuring the soundness of the EGR valve and improving the safety of vehicles and traffic. As a technology related to such an EGR valve, conventionally, a device for removing foreign matter adhering to the EGR valve when the internal combustion engine stops has been known. For example, in the device described in Patent Document 1, when the ignition switch is turned off and the operation of the internal combustion engine stops, the EGR valve is closed and then fully opened. In the device described in Patent Document 2, after the ignition is turned on and the internal combustion engine starts running, when the ignition is turned off, the EGR valve is reciprocally moved near the fully closed position for opening and closing.

[0003] However, when the vehicle is idling and stops or the internal combustion engine stalls, the internal combustion engine may sometimes stop with the ignition switch on. At this time, if foreign matter is bitten into the EGR valve, the EGR valve cannot be fully closed, and EGR gas may flow into the combustion chamber during restart, making it difficult to restart.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent Laid-Open No. 8-303307 (JPH08-303307A)

[0007] Patent Document 2: Japanese Patent Laid-Open No. 2007-64166 (JP2007-064166A). Summary of the Invention

[0008] An EGR valve control device according to one aspect of the present invention includes: an EGR valve that adjusts the exhaust gas recirculation amount of an internal combustion engine mounted on a vehicle; a detection unit that detects a biting state in which foreign matter is bitten into the EGR valve; and a control unit that controls the EGR valve. When the rotation of the internal combustion engine stops with the ignition switch of the vehicle on, the control unit controls the EGR valve to perform opening and closing operations a specified number of times on the condition that the biting state is detected by the detection unit. Brief Description of the Drawings

[0009] The object, features, and advantages of the present invention will be further clarified by the following description of embodiments related to the drawings.

[0010] Figure 1is a diagram schematically showing an example of the peripheral structure of an engine of an EGR valve control device to which an embodiment of the present invention is applied;

[0011] Figure 2 is schematically showing Figure 1 an example of the internal structure of the EGR valve;

[0012] Figure 3 is a timing chart showing an example of the operation of the Figure 1 EGR valve in one driving cycle from when the vehicle ignition switch is turned on to when it is turned off;

[0013] Figure 4 is a block diagram schematically showing an example of the main part configuration of an EGR valve control device according to an embodiment of the present invention;

[0014] Figure 5 is a timing chart showing an example of the opening and closing operation of the EGR valve;

[0015] Figure 6 is a timing chart showing another example of the opening and closing operation of the EGR valve;

[0016] Figure 7 is a timing chart showing an example of the opening and closing operation when there is a start request during the opening and closing operation of the EGR valve;

[0017] Figure 8 is a timing chart showing an example of the opening and closing operation when the ignition switch is turned off during the opening and closing operation of the EGR valve;

[0018] Figure 9 is a flowchart showing an example of the processing executed by the Figure 4 ECU with the vehicle ignition switch turned on;

[0019] Figure 10 is showing Figure 9 a flowchart of a modified example;

[0020] Figure 11 is a flowchart showing an example of the processing executed by the Figure 4 ECU when there is a start request during the opening and closing operation of the EGR valve. Detailed Embodiments

[0021] Hereinafter, embodiments of the present invention will be described with reference to Figures 1 to 11 the drawings. Figure 1FIG. 0 is a diagram schematically showing an example of the peripheral structure of an engine 1 of an EGR valve control device to which an embodiment of the present invention is applied. The engine 1 is an internal combustion engine such as a gasoline engine or a diesel engine mounted on a vehicle (not shown). The vehicle may be equipped with only the engine 1 as a drive source, or may be a hybrid vehicle equipped with the engine 1 and a traveling electric motor. A rotational speed sensor 1a for detecting the engine speed is provided in the engine 1.

[0022] As Figure 1 shown, the engine 1 is connected to an intake passage 3 via an intake manifold 2 and is connected to an exhaust passage 5 via an exhaust manifold 4. The air sucked into the intake passage 3 through an air cleaner (not shown) has its flow rate adjusted by a throttle valve 6 provided in the intake passage 3 and is supplied to the engine 1 via the intake manifold 2. The exhaust discharged from the engine 1 to the exhaust passage 5 through the exhaust manifold 4 is purified by a catalyst device 7 provided in the exhaust passage 5 and released into the atmosphere.

[0023] A part of the exhaust discharged to the exhaust passage 5 is recirculated to the intake passage 3 via an EGR passage 8. The flow rate of the exhaust (EGR gas) recirculated from the exhaust passage 5 to the intake passage 3 through the EGR passage 8, that is, the exhaust gas recirculation amount of the engine 1, is adjusted by an EGR valve 9 provided in the EGR passage 8. A lift sensor 9a for detecting the lift amount of a valve element ( Figure 2 ) corresponding to the opening degree of the EGR valve 9 is provided in the EGR valve 9. The EGR valve 9 is controlled by an ECU (Electronic Control Unit) 10 ( Figure 4 ) mounted on the vehicle.

[0024] Figure 2 FIG. 16 is a diagram schematically showing an example of the internal structure of the EGR valve 9, showing the state where the EGR valve 9 is closed (fully closed). The EGR valve 9 is configured as, for example, an electric lift valve. As Figure 2 shown, the EGR valve 9 has a valve body 90 that forms a part of the EGR passage 8. An inlet side passage 91 connected to the EGR passage 8 on the exhaust passage 5 side and an outlet side passage 92 connected to the EGR passage 8 on the intake passage 3 side are formed in the valve body 90. A substantially annular valve seat 93 centered on a vertical axis CL is provided in the valve body 90 between the inlet side passage 91 and the outlet side passage 92.

[0025] The EGR valve 9 further includes a valve element 94 that can be seated on the valve seat 93, a valve stem 95 integrally provided with the valve element 94, a compression spring 96 that biases the valve element 94 and the valve stem 95 upward, and a solenoid 97 that drives the valve element 94 and the valve stem 95 downward. It should be noted that a motor such as a stepping motor may be used instead of the solenoid to drive the valve element 94 and the valve stem 95. The compression spring 96 and the solenoid 97 are housed in a housing 98 provided above the valve body 90.

[0026] The through hole 93a of the valve seat 93 is a conical table surface centered on the vertical axis CL and expands in diameter upward. The valve core 94 is formed in a substantially conical frustum shape centered on the vertical axis CL and expands in diameter downward. The valve stem 95 is arranged to extend upward along the vertical axis CL from the upper end of the valve core 94 and is supported by a bearing 98a provided in the housing 98 so as to be slidable along the vertical axis CL. A spring seat 95a that protrudes horizontally in the radial outward direction centered on the vertical axis CL is formed on the valve stem 95.

[0027] The lower end of the compression spring 96 abuts against the upper end surface of the bearing 98a, and the upper end of the compression spring 96 abuts against the lower end surface of the spring seat 95a. The compression spring 96 applies an upward force to the valve core 94 and the valve stem 95 via the spring seat 95a. The solenoid 97 is connected to the spring seat 95a and drives the valve core 94 and the valve stem 95 downward via the spring seat 95a.

[0028] As Figure 2 shown, when the solenoid 97 is turned off, the valve core 94 and the valve stem 95 are upwardly biased by the compression spring 96, and the conical table surface of the valve core 94 abuts against the lower end of the valve seat 93 (through hole 93a). Thereby, the valve core 94 seats on the valve seat 93, and thus the EGR valve 9 closes. When the solenoid 97 is turned on, overcoming the acting force of the compression spring 96, the valve stem 95 and the valve core 94 are driven downward, and the valve core 94 moves away from the valve seat 93, whereby the EGR valve 9 opens.

[0029] The lift amount of the valve core 94 corresponding to the opening degree of the EGR valve 9, that is, the amount of separation of the valve core 94 from the valve seat 93, is detected by a lift sensor 9a provided at the upper end of the valve stem 95. The lift amount when the EGR valve 9 is fully closed is 0 mm, and the lift amount when it is fully open is about 5 mm, for example. The energization amount of the solenoid 97 is controlled by the ECU 10 ( Figure 4 ) Thereby, the lift amount (0 - 5 mm) of the EGR valve 9 is adjusted, and the flow rate of the EGR gas is adjusted. The target lift amount of the EGR valve 9 is determined based on a predetermined characteristic according to the operating state of the engine 1, etc., and feedback control is performed on the EGR valve 9 (solenoid 97) so that the lift amount detected by the lift sensor 9a becomes the target lift amount.

[0030] Figure 3 is a timing chart showing an example of the operation of the EGR valve 9 in a single drive cycle from when the ignition switch of the vehicle is turned on to when it is turned off, showing the operation of the EGR valve 9 during cold start. As Figure 3As shown, even when the ignition switch of the vehicle at t1 is turned on, the engine 1 starts running, and the vehicle starts moving, the opening of the EGR valve 9 is prohibited, and the closed valve state is maintained until the engine water temperature reaches the specified water temperature at which the EGR valve 9 can operate. When the specified water temperature is reached at t2, the EGR valve 9 is allowed to open, and the EGR valve 9 is feedback-controlled in such a way as to achieve the target lift amount determined according to the operating state of the engine 1 and the like. After that, when the vehicle decelerates at t3 and enters the deceleration fuel cut state where the fuel supply to the engine 1 is cut off, the vehicle stops at t4, and the EGR valve 9 is instructed to close until the vehicle starts moving again at t5.

[0031] In Figure 3 the example, although the EGR valve 9 is instructed to close during t3 to t5, a lift amount exceeding the specified value α (for example, about 0.5 to 1.0 mm) is still detected. This means that a biting state where foreign matter has bitten into the EGR valve has occurred. For example, when the valve element 94 moves upward (in the valve closing direction) according to the valve closing instruction at t3, the foreign matter that has flowed in from the inlet side passage 91 between t2 and t3 and is sandwiched between the valve seat 93 and the valve element 94 is bitten into the lower end of the valve seat 93 (the through hole 93a) and the conical surface of the valve element 94. Or, the foreign matter that has flowed in from the inlet side passage 91 and passed between the valve seat 93 and the valve element 94 is bitten into the lower end of the valve seat 93 (the through hole 93a) and the conical surface of the valve element 94 at t3. In this case, since the valve element 94 seats on the valve seat 93 with the foreign matter in between, the lift amount becomes larger compared to the lift amount (0 mm) when it abuts without the foreign matter in between, and becomes more than the specified value α (for example, about 0.5 to 1.0 mm). Figure 2 Foreign matter that has bitten into between the valve seat 93 and the valve element 94 like this includes substances such as deposits contained in the EGR gas that are combustion products (oxides, carbides) and have peeled off and become foreign matter while accumulating on the walls of gas flow paths such as the EGR passage 8. When the EGR gas flows through the EGR passage 8, if the EGR valve 9 is at an opening near fully open, such foreign matter will pass through and will not be bitten into between the valve seat 93 and the valve element 94. In addition, when the EGR gas does not flow through the EGR passage 8, by fully opening the EGR valve 9, the foreign matter can be made to fall off downward in the direction of gravity, that is, into the inlet side passage 91.

[0032] If the vehicle starts moving again and the opening of the EGR valve 9 becomes larger, the foreign matter caught in the EGR valve 9 will pass through to the outlet side passage 92 together with the EGR gas. However, when the vehicle is idling and stopped or the engine 1 stalls, if foreign matter has bitten into the EGR valve 9, it may be difficult to restart on its own. That is, since the EGR valve 9 cannot be fully closed in the state where foreign matter has bitten in, EGR gas flows into the combustion chamber during restart, so an appropriate air-fuel ratio cannot be ensured, and restart becomes difficult.

[0033] ​

[0034] Therefore, in the present embodiment, when the foreign matter is bitten into the EGR valve 9 and the engine 1 stops with the ignition switch turned on, the EGR valve control device is configured as follows to remove the bitten foreign matter by opening and closing the EGR valve 9.

[0035] Figure 4 FIG. 5 is a block diagram schematically showing an example of the main configuration of an EGR valve control device (hereinafter referred to as the device) 100 according to an embodiment of the present invention. As Figure 4 shown, the device 100 mainly includes an ECU 10 that controls the EGR valve 9, a rotational speed sensor 1a, a lift sensor 9a, and the EGR valve 9 (solenoid 97) that are respectively connected to the ECU 10. In addition, although not shown in the figure, various sensors mounted on the vehicle, other ECUs, etc. are also connected to the ECU 10, and detection values, command values, etc. of various parameters indicating the driving state of the vehicle such as the accelerator opening and the engine water temperature are input. The ECU 10 is composed of a computer having a processor 11 such as a CPU (Central Processing Unit), a memory 12 such as a ROM (Read Only Memory) and a RAM (Random Access Memory), and other peripheral circuits. The ECU 10 is configured as an engine control ECU, for example, and controls the entire engine 1 including the throttle valve 6, the injector, etc. in addition to the EGR valve 9.

[0036] When the ignition switch of the vehicle is turned off, the ECU 10 controls the EGR valve 9 to perform opening and closing operations a specified number of times (for example, 3 times). More specifically, a target lift amount (0 mm → 5 mm → 0 mm → 5 mm → 0 mm → 5 mm → 0 mm) is indicated to the EGR valve 9 (solenoid 97) so that the valve element 94 of the EGR valve 9 reciprocates between the fully closed position and the fully open position a specified number of times. Thereby, even when foreign matter is bitten into the EGR valve 9, the bitten state can be eliminated, and the startability in the next driving cycle can be ensured. Since the opening and closing operations are performed when the engine 1 is not rotating and the EGR gas is not flowing in the EGR passage 8, the EGR gas does not flow into the combustion chamber due to the opening and closing operations, and the next startability is not affected.

[0037] Even when only one opening and closing operation is performed, the foreign matter can be detached and removed during the period until the valve element 94 reaches the fully open position. When the opening and closing operations are repeated two or more times, the foreign matter can be more reliably detached and removed by the impact when the valve element 94 seats on the valve seat 93, the vibration when folding back from the fully open position, etc.

[0038] After the ignition switch of the vehicle is turned on, on the condition that the EGR valve 9 has operated during the operation of the engine 1, as needed, the ECU 10 controls the EGR valve 9 to perform the same opening and closing operation as when the ignition switch is turned off. That is, when the EGR valve 9 operates in the current driving cycle, a biting state may sometimes occur. However, even if the engine 1 is running in the driving cycle, if the EGR valve 9 does not operate, the biting state will not occur. When the opening and closing operation of the EGR valve 9 is performed, since there is a seating sound when the valve core 94 seats on the valve seat 93 or the operating sound of the solenoid 97, it may cause a sense of discomfort to the driver. In addition, a certain amount of electric power is consumed by the operation of the solenoid 97. By suppressing the opening and closing operation of the EGR valve 9 to the necessary minimum, the sense of discomfort to the driver and the power consumption can be suppressed to the necessary minimum.

[0039] When the rotation of the engine 1 stops with the ignition switch of the vehicle turned on, on the condition that the biting state is detected by the lift sensor 9a, the ECU 10 controls the EGR valve 9 to perform the opening and closing operation. In the operating state where the rotation of the engine 1 stops, the EGR valve 9 is always instructed to close the valve, and the target lift amount (0 mm) corresponding to the fully closed position is indicated. During the period when the EGR valve 9 is instructed to close the valve (target lift amount 0 mm) in the driving cycle, the ECU 10 always compares the lift amount of the EGR valve 9 detected by the lift sensor 9a with a specified value α (for example, about 0.5 to 1.0 mm) at a specified cycle (for example, in units of several seconds). And if the lift amount of the EGR valve 9 is equal to or greater than the specified value α, it is determined that the biting state has occurred. If the lift amount of the EGR valve 9 is less than the specified value α, it is determined that the biting state has not occurred. In the state where it is determined that the biting state has occurred, when the engine speed detected by the engine speed sensor 1a is 0 rpm, the ECU 10 controls the EGR valve 9 to perform the opening and closing operation.

[0040] Even in the driving cycle, during idling stop, when driving alone with the driving electric motor in a hybrid vehicle (EV driving), when the engine 1 stalls, etc., the rotation of the engine 1 sometimes stops. In this case, there is a high possibility of immediate restart. When the rotation of the engine 1 stops in the driving cycle and the biting state occurs, by controlling the EGR valve 9 to perform the opening and closing operation, foreign matters can be removed and the restartability can be ensured. In addition, by performing the opening and closing operation of the EGR valve 9 only when the biting state is detected, the sense of discomfort to the driver and the power consumption can be suppressed to the necessary minimum.

[0041] It should be noted that for the opening and closing operation of the EGR valve 9 when the ignition switch is turned off, it can also be performed on the condition that the biting state is detected. In this case, the sense of discomfort to the driver and the power consumption can be further suppressed.

[0042] Figure 5 is a timing chart showing an example of the opening and closing operation of the EGR valve 9. As Figure 3 and Figure 5 shown, at t1, the ignition switch of the vehicle is turned on. At t2 - t3, the EGR valve 9 operates. At t3, it is determined that the biting state of the EGR valve 9 has occurred. After that, in the state where it is determined that the biting state has occurred, when the rotation of the engine 1 stops at t4, at t7, the opening and closing operation of the EGR valve 9 is performed to remove the bitten foreign object, and the lift amount becomes 0 mm. In addition, when the ignition switch is turned off at t10, the opening and closing operation of the EGR valve 9 is performed at t11. However, if the EGR valve 9 does not operate after the opening and closing operation at t7, the opening and closing operation of the EGR valve 9 at t11 is not performed.

[0043] It is also possible that when the rotation of the engine 1 stops during a driving cycle, on the condition that it is contrary to the subsequent restart request and the engine 1 does not start, the ECU 10 determines whether the biting state has occurred, and performs the opening and closing operation of the EGR valve 9 according to the determination result. That is, after the engine speed detected by the speed sensor 1a during the driving cycle becomes 0 rpm, when the restart of the engine 1 in response to the restart request fails, the lift amount of the EGR valve 9 detected by the lift sensor 9a is compared with the specified value α. If the lift amount is equal to or greater than the specified value α, it is determined that the biting state has occurred, and the opening and closing operation of the EGR valve 9 is controlled. If the lift amount is less than the specified value α, it is determined that the biting state has not occurred, and the opening and closing operation is not performed.

[0044] It should be noted that the restart request includes the restart request indicated from the engine system side when resuming from the idle stop in response to the driver's operation of disconnecting the brake in the forward gear (D gear), or when changing from EV driving to driving using the engine 1. In addition, it also includes the restart request indicated in response to the driver's operation of turning on the starter with the ignition switch in the parking gear (P gear) when the engine 1 stalls, etc.

[0045] Even if the biting state of the EGR valve 9 occurs, if the restart is successful, then later, when the vehicle starts to drive again and the opening degree of the EGR valve 9 becomes larger, the foreign object bitten into the EGR valve 9 will pass through to the outlet side passage 92 together with the EGR gas. In the case of a restart failure, it is determined whether the biting state has occurred, and the opening and closing operation of the EGR valve 9 is performed according to the determination result, thereby further suppressing the discomfort felt by the driver and power consumption.

[0046] Figure 6 is a timing chart showing an example of the opening and closing operation of the EGR valve 9 when determining whether the biting state has occurred on the condition of a restart failure. As Figure 3 and Figure 6As shown, the ignition switch is turned on at t1, the EGR valve 9 operates from t2 to t3, and it is determined at t3 that the biting state of the EGR valve 9 has occurred. After that, in the state where it is determined that the biting state has occurred, the rotation of the engine 1 is stopped at t4. At t5, when the restart of the engine 1 fails, at t8, the opening and closing operation of the EGR valve 9 is performed to remove the foreign object that has been bitten, and the lift amount becomes 0 mm. At t5, due to the rotational power output shaft being rotated in response to the restart request, the engine speed temporarily increases and then fails to reach a complete ignition start, and the engine speed returns to 0 rpm, resulting in a restart failure.

[0047] Figure 7 FIG. is a timing chart showing an example of the opening and closing operation when there is a start request during the opening and closing operation of the EGR valve 9. When there is a start request for the engine 1 during the opening and closing operation of the EGR valve 9, the ECU 10 controls the EGR valve 9 to abort the opening and closing operation and close it. More specifically, if at the moment of the start request, the valve element 94 is moving in the direction away from the valve seat 93 (i.e., during the valve opening operation), the subsequent valve opening operation is prohibited, and the valve element 94 is seated on the valve seat 93. If at the moment of the start request, the valve element 94 is moving in the direction of seating on the valve seat 93 (i.e., during the valve closing operation), the valve closing operation is continued until the valve element 94 is seated on the valve seat 93, and at the moment when the valve element 94 is seated on the valve seat 93, the subsequent valve opening operation is prohibited. Additionally, the subsequent valve opening operation can also be prohibited at the moment when the valve element 94 is seated on the valve seat 93 after the start request. In this case, since the EGR valve 9 is at least once in the fully open state, foreign objects can be removed more reliably. Such a start request includes the restart request during the driving cycle and the start request for the next driving cycle immediately after the ignition switch is just turned off, i.e., the current driving cycle.

[0048] As Figure 7 shown, when the opening and closing operation of the EGR valve 9 starts at t20 and there is a start request immediately after the start of the second opening and closing operation in a specified number of times (e.g., 3 times), at the moment when the valve is closed at t21, the opening and closing operation ends, and then the rotational power output shaft starts to rotate at t22. There is a certain delay time from the generation of the start request to the start of the rotation of the power output shaft. Therefore, by stopping the opening and closing operation according to the start request, the EGR valve 9 can be reliably in the fully closed state when the rotation of the power output shaft starts.

[0049] Figure 8 FIG. is a timing chart showing an example of the opening and closing operation when the ignition switch is turned off during the opening and closing operation of the EGR valve 9. The ECU 10 controls the EGR valve 9 so that the opening and closing operation continues even if the ignition switch is turned off during the opening and closing operation. As Figure 8As shown, the opening / closing operation of the EGR valve 9 starts at t30. Even if the ignition switch is turned off at t31 during the opening / closing operation for a specified number of times (e.g., 3 times), the opening / closing operation for the specified number of times will be completed. As a result, foreign matter caught by the EGR valve 9 can be reliably removed, and starting performance in the next driving cycle can be ensured.

[0050] Figure 9 and Figure 10 is a flowchart showing an example of the processing executed by the ECU 10 in a state where the ignition switch of the vehicle is turned on. The processing shown in these flowcharts starts when the ECU 10 is started and is repeated at regular time intervals. As Figure 9 shown, first in S1 (S: processing step), it is determined whether there is a history of the EGR valve 9 having operated in the current driving cycle. When S1 is negative (S1: no), the processing ends. When it is positive (S1: yes), the process proceeds to S2. In S2, it is determined whether the lift amount of the EGR valve 9 detected by the lift sensor 9a when instructing the EGR valve 9 to close is equal to or greater than a specified value α. When S2 is negative (S2: no), the processing ends. When it is positive (S2: yes), the process proceeds to S3. In S3, it is determined whether the engine speed detected by the rotational speed sensor 1a changes from a state above the idle speed to 0 rpm. When S3 is negative (S3: no), the processing ends. When it is positive (S3: yes), the process proceeds to S4, and the opening / closing operation of the EGR valve 9 starts.

[0051] Figure 10 is Figure 9 a modified example, showing an example of the processing for determining whether a biting state occurs on the condition of a restart failure. For the processing different from Figure 9 it is explained that in the processing of Figure 10 , when S2 is positive (S2: yes), the process proceeds to S3A. After the engine speed becomes 0 rpm in the driving cycle, it is determined whether the restart of the engine 1 corresponding to the restart request fails. When S3A is negative (S3A: no), the processing ends. When it is positive (S3A: yes), the process proceeds to S4.

[0052] Figure 11 is a flowchart showing an example of the processing executed by the ECU 10 when there is a start request during the opening / closing operation of the EGR valve 9. The processing shown in this flowchart is repeated at regular time intervals during the opening / closing operation of the EGR valve 9. As Figure 11 shown, in S5, it is determined whether a start request has occurred. When it is negative (S5: no), the processing ends. On the other hand, when it is positive (S5: yes), the process proceeds to S6, and the opening / closing operation of the EGR valve 9 is stopped.

[0053] By adopting the embodiment of the present invention, the following effects can be achieved.

[0054] (1) The device 100 includes: an EGR valve 9 that adjusts the exhaust gas recirculation amount of the engine 1 mounted on a vehicle; a lift sensor 9a that detects the biting state of foreign matter being bitten into the EGR valve 9; and an ECU 10 that controls the EGR valve 9 ( Figure 1 、 Figure 2 、 Figure 4 ). When the rotation of the engine 1 stops while the ignition switch of the vehicle is on, the ECU 10 controls the EGR valve 9 to perform an opening and closing operation a specified number of times on the condition that the biting state is detected by the lift sensor 9a ( Figure 5 、 Figure 9 in S2 - S4). Thus, when the engine rotation stops during a driving cycle where there is a high probability of restarting immediately afterwards, foreign matter bitten into the EGR valve 9 can be removed to ensure restartability. In addition, the opening and closing operation of the EGR valve 9 is only performed when the biting state is actually detected, thereby suppressing the sense of discomfort and power consumption caused to the driver to the necessary minimum.

[0055] (2) When the rotation of the engine 1 stops while the ignition switch is on, further, on the condition that the engine 1 does not start contrary to the start request of the engine 1, the ECU 10 controls the EGR valve 9 to perform an opening and closing operation ( Figure 6 、 Figure 10 in S2A, S4). In the case of a restart failure, it is determined whether the biting state occurs, and the opening and closing operation of the EGR valve 9 is performed according to the determination result, thereby further suppressing the sense of discomfort and power consumption caused to the driver.

[0056] (3) When the ignition switch is turned off, the ECU 10 further controls the EGR valve 9 to perform an opening and closing operation ( Figure 5 ). Thus, even if foreign matter is bitten into the EGR valve 9 at the end of the current driving cycle, the biting state can be eliminated, and the startability in the next driving cycle can be ensured.

[0057] (4) When there is a start request for the engine 1 during the opening and closing operation, the ECU 10 controls the EGR valve 9 to abort the opening and closing operation and close it ( Figure 7 、 Figure 11 ). By stopping the opening and closing operation in response to the start request, the EGR valve 9 can be reliably fully closed when starting to rotate the power output shaft.

[0058] (5) Even if the ignition switch is turned off during the opening and closing operation, the ECU 10 controls the EGR valve 9 to continue the opening and closing operation ( Figure 8 ). Thus, foreign matter bitten into the EGR valve 9 can be reliably removed, and the startability in the next driving cycle can be ensured.

[0059] (6) After the ignition switch is turned on, on the condition that the EGR valve 9 operates during the operation of the engine 1, the ECU 10 controls the EGR valve 9 to perform an opening and closing operation ( Figure 9 、 Figure 10 ). That is, when the EGR valve 9 does not operate during the current driving cycle, the biting state will not occur, so the opening and closing operation of the EGR valve 9 is not performed. By suppressing the opening and closing operation of the EGR valve 9 to the minimum necessary, the discomfort and power consumption brought to the driver can be suppressed to the minimum necessary.

[0060] The above-described embodiment can be modified in various ways. Hereinafter, modification examples will be described. In the above-described embodiment, an example in which the exhaust gas after passing through the catalyst device 7 is returned as EGR gas is described with reference to Figure 1 etc., but as long as the internal combustion engine has an EGR valve for adjusting the exhaust gas recirculation amount, the configuration of each part of the internal combustion engine is not limited to the illustrated configuration. For example, the exhaust gas before passing through the catalyst device 7 can also be returned as EGR gas. The EGR passage 8 can be directly connected to the exhaust manifold 4 instead of the exhaust passage 5, can be directly connected to the intake manifold 2 instead of the intake passage 3, or can be connected to the intake manifold 2 via an appropriate chamber for mixing EGR gas and fresh air, etc.

[0061] In the above-described embodiment, an example in which the biting state of the EGR valve 9 is detected using the lift sensor 9a is described with reference to Figure 1 、 2 、4 etc., but the detection unit for detecting the biting state of foreign matter being bitten into the EGR valve is not limited to this. For example, an appropriate concentration sensor can be provided in the EGR passage 8 downstream of the EGR valve 9 to detect the concentration of the gas components contained in the exhaust gas, and the inflow of EGR gas and the biting state of the EGR valve 9 can be detected based on the detected concentration.

[0062] In the above-described embodiment, the specific internal structure of the EGR valve 9 is illustrated with reference to Figure 2 etc., but the EGR valve is not limited to the illustrated structure. For example, it can also be a valve other than a lift valve such as a butterfly valve. That is, in a butterfly valve, etc., foreign matter may sometimes be bitten in in the same way as a lift valve, and by fully opening the valve, the same foreign matter removal can be performed. It should be noted that when using a butterfly valve, an angle sensor can be used instead of a lift sensor to detect the valve opening degree.

[0063] In the above-described embodiment, the lift amount (5 mm) when the valve is fully opened, the specified value α (0.5 to 1.0 mm) for the biting state, etc. are illustrated with reference to Figure 3 、 Figures 5 to 8 etc., but these are only examples for illustration, and the specifications of the EGR valve are not limited to the illustrated specifications.

[0064] One or more of the above-described embodiments and modifications can be arbitrarily combined, and the modifications can also be combined with each other.

[0065] By adopting the present invention, the restartability when the internal combustion engine stops in the state where the ignition switch is turned on can be ensured.

[0066] The present invention has been described above in conjunction with the preferred embodiments, but those skilled in the art should understand that various modifications and changes can be made without departing from the scope of disclosure of the claims.

Claims

1. An EGR valve control device (100), characterized in that, Comprising: an EGR valve (9) that adjusts the exhaust gas recirculation amount of an internal combustion engine (1) mounted on a vehicle; a detection unit (9a) that detects a biting state in which a foreign object is bitten into the EGR valve (9); and a control unit (10) that controls the EGR valve (9), when the rotation of the internal combustion engine (1) stops while the ignition switch of the vehicle is on, the control unit (10) controls the EGR valve (9) to perform an opening / closing operation a specified number of times on the condition that the biting state is detected by the detection unit (9a).

2. The EGR valve control device (100) according to claim 1, characterized in that when the rotation of the internal combustion engine (1) stops while the ignition switch is on, further, on the condition that a start request for the internal combustion engine (1) is contrary and the internal combustion engine (1) does not start, the control unit (10) controls the EGR valve (9) to perform the opening / closing operation.

3. The EGR valve control device (100) according to claim 1, characterized in that when the ignition switch is off, the control unit (10) further controls the EGR valve (9) to perform the opening / closing operation.

4. The EGR valve control device (100) according to any one of claims 1 to 3, characterized in that when there is a start request for the internal combustion engine during the opening / closing operation, the control unit (10) controls the EGR valve (9) to abort the opening / closing operation and close it.

5. The EGR valve control device (100) according to claim 1 or 2, characterized in that even if the ignition switch is off during the opening / closing operation, the control unit (10) controls the EGR valve (9) to continue the opening / closing operation.

6. The EGR valve control device (100) according to any one of claims 1 to 3, characterized in that after the ignition switch is turned on, on the condition that the EGR valve (9) operates during the operation of the internal combustion engine (1), the control unit (10) controls the EGR valve (9) to perform the opening / closing operation.

7. The EGR valve control device (100) according to any one of claims 1 to 3, characterized in that the detection unit 9a has a sensor that detects the opening degree of the EGR valve (9).

8. The EGR valve control device (100) according to claim 7, characterized in that when instructing the EGR valve (9) to close, if the opening degree detected by the sensor is equal to or greater than a specified value, the detection unit (9a) detects the biting state.

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