JP2013234616A - Control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device of an internal combustion engine that can suppress corrosion of a fuel injection valve caused by adhesion of condensed water sucked in a combustion chamber.SOLUTION: An internal combustion engine (5) has a fuel injection valve (50) for directly injecting fuel to a combustion chamber (14) and a swirling airflow intensity changing means (60) for changing intensity of a swirling airflow which flows along an inner peripheral sidewall (15) of the combustion chamber. A control device (100) of the internal combustion engine includes a control part for performing swirling airflow intensity increase control that controls the swirling airflow intensity changing means, when a condensed water suction condition is met where an operation state of the internal combustion engine is an operation sate where the condensed water is estimated to be sucked in the combustion chamber, so that the intensity of the swirling airflow formed in the combustion chamber is increased compared with that before the condensed water suction condition is met.

Description

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

  2. Description of the Related Art Conventionally, an in-cylinder direct injection internal combustion engine including a fuel injection valve that directly injects fuel into a combustion chamber is known. For example, Patent Document 1 discloses a diesel engine including a fuel injection valve that directly injects fuel into a combustion chamber.

JP 2007-16611 A

  In the in-cylinder direct injection internal combustion engine as shown in Patent Document 1, condensed water may be sucked into the combustion chamber. When condensed water is sucked into the combustion chamber, the condensed water sucked into the combustion chamber adheres to the fuel injection valve, and as a result, the fuel injection valve may corrode.

  An object of the present invention is to provide a control device for an internal combustion engine that can suppress corrosion of a fuel injection valve caused by adhering condensed water sucked into a combustion chamber.

  An internal combustion engine control apparatus according to the present invention includes a fuel injection valve that directly injects fuel into a combustion chamber, and a swirling airflow strength changing unit that changes the strength of the swirling airflow flowing along the inner peripheral side wall of the combustion chamber. When the condensate intake condition that the operation state of the internal combustion engine is an operation state in which it is estimated that condensate is sucked into the combustion chamber is satisfied, the swirl airflow formed in the combustion chamber A control unit is provided that executes swirl airflow strength increase control for controlling the swirl airflow strength changing means so that the strength becomes stronger than before the condensed water suction condition is satisfied.

  According to the control apparatus for an internal combustion engine according to the present invention, even when the condensed water intake condition is satisfied, even if condensed water is sucked into the combustion chamber, the strength is increased by executing the swirl airflow strength increase control. For example, the condensed water sucked into the combustion chamber can be blown to the inner peripheral side wall of the combustion chamber by the swirling airflow. As a result, it is possible to suppress the condensed water sucked into the combustion chamber from adhering to the fuel injection valve. Thereby, corrosion of the fuel injection valve due to the adhering condensed water sucked into the combustion chamber can be suppressed.

  In the above configuration, when the condensate intake condition is satisfied, the control unit further satisfies a condensate amount condition that the amount of the condensate sucked into the combustion chamber is equal to or greater than a predetermined amount. The swirl airflow strength increase control may be executed at the same time, and when the condensate amount condition is not satisfied, the swirl airflow strength increase control may be prohibited.

  It is considered that the greater the amount of condensed water sucked into the combustion chamber, the higher the risk of corrosion of the fuel injection valve due to the condensed water sucked into the combustion chamber adhering to the fuel injection valve. In addition, when the swirl airflow strength increase control is executed, the adhesion of the condensed water sucked into the combustion chamber to the fuel injection valve can be suppressed and corrosion of the fuel injection valve can be suppressed. May increase. On the other hand, according to this configuration, when the risk of corrosion of the fuel injection valve due to the condensed water sucked into the combustion chamber adhering to the fuel injection valve is high, the fuel injection is performed by executing the swirl airflow strength increase control. When the risk of corrosion of the fuel injection valve is not high while suppressing the corrosion of the valve, the increase in the amount of unburned HC emission can be suppressed by prohibiting the execution of the swirling airflow strength increase control.

  In the above configuration, when the condensed water suction condition is satisfied, the control unit further satisfies the condensed water pH condition that the pH of the condensed water sucked into the combustion chamber is equal to or lower than a predetermined pH. In this case, the swirl airflow strength increase control may be executed, and if the condensate water condition is not satisfied, the swirl airflow strength increase control may be prohibited.

  The lower the pH of the condensed water sucked into the combustion chamber, the stronger the acidity of the condensed water. As a result, the fuel injection valve may corrode due to the condensed water sucked into the combustion chamber adhering to the fuel injection valve. Will be higher. On the other hand, according to this configuration, when the risk of corrosion of the fuel injection valve due to the condensed water sucked into the combustion chamber adhering to the fuel injection valve is high, the fuel injection is performed by executing the swirl airflow strength increase control. When the risk of corrosion of the fuel injection valve is not high while suppressing the corrosion of the valve, the increase in the amount of unburned HC emission can be suppressed by prohibiting the execution of the swirling airflow strength increase control.

  In the above configuration, when the condensate suction condition is satisfied, the controller further turns the swirl airflow when a fuel injector temperature condition that the temperature of the fuel injector is equal to or lower than a predetermined temperature is satisfied. The strength increase control is executed, and when the fuel injection valve temperature condition is not satisfied, the execution of the swirl airflow strength increase control may be prohibited.

  When the condensed water sucked into the combustion chamber adheres to the fuel injection valve, the lower the temperature of the fuel injection valve, the smaller the evaporation amount of the condensed water attached to the fuel injection valve. It is considered that the risk of corrosion of the fuel injection valve due to adhesion increases. On the other hand, according to this configuration, when the risk of corrosion of the fuel injection valve due to the condensed water sucked into the combustion chamber adhering to the fuel injection valve is high, the fuel injection is performed by executing the swirl airflow strength increase control. When the risk of corrosion of the fuel injection valve is not high while suppressing the corrosion of the valve, the increase in the amount of unburned HC emission can be suppressed by prohibiting the execution of the swirling airflow strength increase control.

  In the above configuration, the swirling airflow may be a swirl airflow. According to this configuration, corrosion of the fuel injection valve due to the adhering condensed water sucked into the combustion chamber can be effectively suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, the control apparatus of the internal combustion engine which can suppress the corrosion of a fuel injection valve by the condensed water suck | inhaled in a combustion chamber adhering can be provided.

FIG. 1A is a schematic diagram of the internal combustion engine according to the first embodiment. FIG. 1B and FIG. 1C are schematic views for explaining the fuel injection valve. FIG. 2 is a diagram illustrating an example of a flowchart when the control unit of the control device according to the first embodiment executes the swirling airflow strength increase control. FIG. 3 is a schematic perspective view for explaining the effect of the swirling airflow strength increase control by the control device according to the first embodiment. FIG. 4 is a diagram illustrating an example of a flowchart when the control unit of the control device according to the second embodiment executes the swirling airflow strength increase control. Fig.5 (a)-FIG.5 (c) are schematic diagrams which show an example of the map used when the control part which concerns on Example 2 acquires the quantity of condensed water. FIG. 6 is a diagram for explaining the relationship between the strength of the swirling airflow and the unburned HC. FIG. 7 is a diagram illustrating an example of a flowchart when the control unit of the control device according to the first modification of the second embodiment executes the swirling airflow strength increase control. FIGS. 8A and 8B are schematic diagrams illustrating an example of a map used when the control unit according to the first modification of the second embodiment acquires the pH of condensed water. FIG. 9 is a diagram illustrating an example of a flowchart when the control unit of the control device according to the second modification of the second embodiment executes the swirl airflow strength increase control. FIG. 10A and FIG. 10B are schematic diagrams illustrating an example of a map used when the control unit according to the second modification of the second embodiment acquires the temperature of the fuel injection valve.

  Hereinafter, modes for carrying out the present invention will be described.

  An internal combustion engine control apparatus 100 (hereinafter referred to as a control apparatus 100) according to Embodiment 1 of the present invention will be described. First, the overall configuration of the internal combustion engine 5 to which the control device 100 is applied will be described, and then the details of the control device 100 will be described. FIG. 1A is a schematic diagram of the internal combustion engine 5. The internal combustion engine 5 is an in-cylinder direct injection internal combustion engine that directly injects fuel into the combustion chamber 14. If it is such an internal combustion engine, the type of the internal combustion engine 5 is not particularly limited, and an in-cylinder direct injection gasoline engine using gasoline as a fuel, an in-cylinder direct injection diesel engine using light oil as a fuel, etc. Various in-cylinder direct injection internal combustion engines can be used. In this embodiment, as an example of the internal combustion engine 5, a direct injection type diesel engine using light oil as fuel is used.

  The internal combustion engine 5 includes a cylinder block 10, a cylinder head 11, a piston 12, an intake passage 20, an exhaust passage 25, a catalyst 30, a supercharger 40, a fuel injection valve 50, and an airflow control valve 60. , An EGR (Exhaust Gas Recirculation) device 70, various sensors, and a control device 100.

  The cylinder head 11 is disposed above the cylinder block 10. A cylinder 13 is formed in the cylinder head 11 and the cylinder block 10. The piston 12 is disposed in the cylinder 13. A crankshaft (not shown) is connected to the piston 12. A combustion chamber 14 is formed in a region surrounded by the cylinder block 10, the cylinder head 11, and the piston 12.

  The intake passage 20 is a passage through which intake air that is gas before being sucked into the combustion chamber 14 passes. In the present embodiment, the intake air flowing into the end of the intake passage 20 opposite to the combustion chamber 14 is air. The exhaust passage 25 is a passage through which exhaust, which is a gas after burning in the combustion chamber 14, passes. An intake valve (not shown) is arranged at the end of the intake passage 20 on the combustion chamber 14 side, and an exhaust valve (not shown) is arranged at the end of the exhaust passage 25 on the combustion chamber 14 side. In the present embodiment, two intake passages 20 and two exhaust passages 25 are connected to the combustion chamber 14 (see FIG. 1B described later). A throttle valve (not shown) is also disposed in the intake passage 20. Specifically, the throttle valve is disposed upstream of the supercharger 40 in the intake passage 20 in the intake flow direction. However, the location of the throttle valve is not limited to this.

  The catalyst 30 is disposed in the exhaust passage 25. Specifically, the catalyst 30 is disposed downstream of the supercharger 40 in the exhaust passage 25 in the exhaust flow direction. The catalyst 30 is a catalyst for purifying the exhaust gas that passes through the exhaust passage 25. The type of the catalyst 30 is not particularly limited as long as the catalyst can purify the exhaust gas. In this embodiment, a three-way catalyst is used as the catalyst 30.

  The supercharger 40 is a device that compresses intake air taken into the internal combustion engine 5. Although the specific configuration of the supercharger 40 is not particularly limited, the supercharger 40 according to this embodiment includes a turbine 41 and a compressor 42. The turbine 41 is disposed in the exhaust passage 25. The compressor 42 is disposed in the intake passage 20. The compressor 42 is connected to the turbine 41 so as to rotate integrally with the turbine 41 when the turbine 41 rotates. The turbine 41 rotates by receiving a force from the exhaust gas passing through the exhaust passage 25. When the turbine 41 rotates, the compressor 42 connected to the turbine 41 also rotates. As the compressor 42 rotates, the intake air passing through the intake passage 20 is compressed. In this way, the supercharger 40 compresses the intake air and supplies it to the internal combustion engine 5 (ie, supercharging).

  The fuel injection valve 50 is a valve that injects fuel. The fuel injection valve 50 is disposed in the internal combustion engine 5 so as to inject fuel (F) directly into the combustion chamber 14. FIG. 1B and FIG. 1C are schematic diagrams for explaining the fuel injection valve 50. Specifically, FIG. 1B schematically illustrates a state in which the vicinity of the fuel injection valve 50 in the combustion chamber 14 is viewed from an oblique direction. FIG. 1C schematically shows a portion of the fuel injection valve 50 disposed in the combustion chamber 14 (portion in the combustion chamber 14).

  The fuel injection valve 50 according to the present embodiment includes a portion (hereinafter referred to as a nozzle 51) having a nozzle shape at the tip. A nozzle hole 52 which is a hole through which fuel is injected is formed at the further tip of the nozzle 51. The fuel injection valve 50 is supported by the cylinder head 11 of the internal combustion engine 5 so that fuel is directly injected into the combustion chamber 14 from the injection hole 52. The fuel injection valve 50 is disposed in the center of the ceiling portion of the combustion chamber 14. The fuel injection valve 50 injects fuel from the injection hole 52 toward the top surface of the piston 12. However, the arrangement location of the fuel injection valve 50 is not limited to the location shown in FIGS. 1A to 1C as long as the fuel can be directly injected into the combustion chamber 14.

  With reference to FIG. 1A, the airflow control valve 60 is disposed in the intake passage 20. The airflow control valve 60 is a valve that changes the strength of the swirling airflow formed in the combustion chamber 14. Here, the internal combustion engine 5 according to the present embodiment is configured such that the airflow flowing into the combustion chamber 14 in the intake stroke becomes a swirling airflow in the combustion chamber 14. The type of swirling airflow formed in the combustion chamber 14 is not particularly limited as long as it flows along the inner peripheral side wall 15 (shown in FIG. 1B) of the combustion chamber 14. .

  In this embodiment, a swirl flow (SW) is used as an example of the swirling airflow. In this case, the swirl flow turns in the combustion chamber 14 in the lateral direction (circumferential direction). A swirl control valve is used as the airflow control valve 60. The airflow control valve 60 is disposed in a portion of the two intake passages 20 connected to the combustion chamber 14 on the downstream side in the intake flow direction with respect to the connection location of the EGR passage 71 of one intake passage 20. When the airflow control valve 60 changes the opening degree of the one intake passage 20, the strength of the swirling airflow formed in the combustion chamber 14 can be changed. Note that the swirling airflow intensity changing method by the airflow control valve 60 is not limited to this method.

  Further, the internal combustion engine 5 may include a configuration other than the airflow control valve 60 as in the present embodiment as the swirling airflow intensity changing means. As another example of the swirling airflow intensity changing means, a variable valve timing mechanism can be used. In this case, the variable valve timing mechanism changes the valve timing of the intake valve of one of the two intake passages 20 connected to the combustion chamber 14 with respect to the valve timing of the other intake valve. Also in this case, the strength of the swirling airflow formed in the combustion chamber 14 can be changed.

  The EGR device 70 is a device that recirculates a part of the exhaust discharged from the combustion chamber 14 to the combustion chamber 14. The specific configuration of the EGR device 70 is not particularly limited, but the EGR device 70 according to the present embodiment includes an EGR passage 71, an EGR valve 72, and an EGR cooler 73. The EGR passage 71 is a passage for recirculating a part of the exhaust discharged from the combustion chamber 14 to the combustion chamber 14. The EGR passage 71 according to the present embodiment communicates the passageway of the exhaust passage 25 and the passageway of the intake passage 20. Hereinafter, the exhaust gas that passes through the EGR passage 71 is referred to as EGR gas.

  The EGR valve 72 is disposed in the EGR passage 71. The EGR valve 72 is a valve that controls the amount of EGR gas that passes through the EGR passage 71. When the EGR passage 71 is closed by closing the EGR valve 72, the EGR gas does not flow into the intake passage 20. When the EGR passage 71 is opened by opening the EGR valve 72, the EGR gas flows into the intake passage 20 and mixes with air, and then recirculates to the combustion chamber 14. In this case, gas containing air and EGR gas is sucked into the combustion chamber 14. As the opening degree of the EGR valve 72 increases, the opening degree of the EGR passage 71 also increases, and as a result, the amount of EGR gas passing through the EGR passage 71 per unit time also increases.

  The EGR cooler 73 is disposed in the EGR passage 71. The EGR cooler 73 is a device that cools the EGR gas. The specific configuration of the EGR cooler 73 is not particularly limited as long as the EGR gas can be cooled. In the present embodiment, an EGR cooler that cools EGR gas using a refrigerant is used as the EGR cooler 73. The arrangement location of the EGR cooler 73 in the EGR passage 71 is not particularly limited, but the EGR cooler 73 according to the present embodiment is arranged upstream of the EGR valve 72 in the EGR passage 71 in the EGR gas flow direction. ing.

  The various sensors are sensors that detect information necessary for control of the control device 100. In FIG. 1A, a crank position sensor 80 is shown as an example of various sensors. The crank position sensor 80 detects the position of the crankshaft and transmits the detection result to the control device 100. The control device 100 acquires the crank angle of the internal combustion engine 5 based on the detection result of the crank position sensor 80. In addition, each stroke of the internal combustion engine 5 such as the intake stroke, the compression stroke, the fuel injection timing, the position of the intake valve and the exhaust valve, the position of the piston 12, and the like are based on the crank angle. Therefore, the control device 100 can acquire these states by acquiring the crank angle. The control device 100 according to the present embodiment also acquires the rotational speed (rpm) of the internal combustion engine 5 based on the detection result of the crank position sensor 80. Although not shown in FIG. 1A, the internal combustion engine 5 also includes an air flow meter that detects the amount of air flowing into the intake passage 20 (intake air amount).

  The control device 100 includes a control unit that controls the internal combustion engine 5 and a storage unit that stores information necessary for the operation of the control unit. An electronic control unit (Electronic Control Unit) can be used as the control device 100. In the present embodiment, as an example of the control device 100, an electronic control device including a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, and a RAM (Random Access Memory) 103 is used. The function of the control unit is realized by the CPU 101. The function of the storage unit is realized by the ROM 102 and the RAM 103.

  The storage unit stores a map of a required fuel injection amount that is a fuel injection amount required for the internal combustion engine 5. In this map, the required fuel injection amount is defined in association with the intake air amount of the internal combustion engine 5 and the rotational speed of the internal combustion engine 5. The control unit calculates the fuel injection amount from the map of the required fuel injection amount based on the intake air amount acquired based on the detection result of the air flow meter and the rotation speed of the internal combustion engine 5 acquired based on the detection result of the crank position sensor 80. The fuel injection valve 50 is controlled so that the extracted fuel injection amount is injected. In addition, the control unit corrects the fuel injection amount according to the operating state of the internal combustion engine 5 such as the refrigerant temperature of the internal combustion engine 5 and the acceleration of the internal combustion engine 5.

  The control unit also controls the EGR valve 72 so that the EGR rate, which is a value obtained by dividing the amount of EGR gas by the amount of intake air (the sum of the amount of air and the amount of EGR gas), becomes a predetermined target EGR rate. ing. The specific method for obtaining the EGR rate by the control unit is not particularly limited, but the control unit according to the present embodiment is based on the detection result of the air flow meter and the opening degree of the EGR valve 72. To get. The EGR rate can be acquired based on the amount of air and the amount of EGR gas, the amount of air can be acquired based on the detection result of the air flow meter, and the amount of EGR gas can be calculated based on the opening of the EGR valve 72. It is because it can acquire based on. However, the specific control method of the EGR valve 72 by the control unit is not limited to this.

  Further, the control unit forms in the combustion chamber 14 when the condensate intake condition that the operation state of the internal combustion engine 5 is an operation state in which the condensate is estimated to be sucked into the combustion chamber 14 is satisfied. The swirling air flow strength increase control for controlling the air flow control valve 60 is executed so that the strength of the swirling air flow is stronger than before the condensed water suction condition is satisfied. In this embodiment, the strength of the swirling airflow is increased when the rotational speed of the swirling airflow (the number of rotations of the swirling airflow per cycle of the internal combustion engine 5) is increased.

  FIG. 2 is a diagram illustrating an example of a flowchart when the control unit of the control device 100 executes the swirling airflow strength increase control. The control unit repeatedly executes the flowchart of FIG. 2 at predetermined time intervals. It is assumed that the opening degree of the airflow control valve 60 is set to a predetermined value at the first start time of the flowchart according to FIG. 2, and as a result, the strength of the swirling airflow is set to a predetermined value.

  First, the control unit determines whether or not the condensed water intake condition is satisfied (step S10). In step S10, the control unit determines that the condensed water intake condition is satisfied when the operation state of the internal combustion engine 5 satisfies both a first operation state and a second operation state described below.

  First, the first operating state will be described. The first operating state is any one of the operating states when the internal combustion engine 5 is decelerated, the internal combustion engine 5 is suddenly accelerated, and the internal combustion engine 5 is started. First, the case where the internal combustion engine 5 is decelerated will be described. When the internal combustion engine 5 decelerates, there is a high possibility that the pressure in the intake passage 20 becomes negative. When the pressure in the intake passage 20 becomes negative, it is estimated that condensed water present in the EGR passage 71 is sucked into the combustion chamber 14.

  Specifically, when the internal combustion engine 5 decelerates, the control unit according to the present embodiment controls the throttle valve to close and controls the EGR valve 72 to open, thereby applying the engine brake. By controlling the throttle valve and the EGR valve 72 in this way, it is possible to suppress the temperature of the catalyst 30 from decreasing when the internal combustion engine 5 is decelerated. However, when the throttle valve and the EGR valve 72 are controlled in this way, the inside of the intake passage 20 becomes negative pressure. In this case, it is estimated that the condensed water present in the EGR passage 71 is sucked into the combustion chamber 14.

  The control unit can determine whether or not the internal combustion engine 5 is decelerating based on, for example, the rotational speed of the internal combustion engine 5. In this case, the storage unit stores a reference value of the rotational speed in advance, and the control unit stores the rotational speed of the internal combustion engine 5 acquired based on the detection result of the crank position sensor 80 below the reference value of the storage unit. It can be determined that the internal combustion engine 5 is decelerating. However, a specific method for determining whether or not the internal combustion engine 5 is decelerating by the control unit is not limited to this.

  Next, the case where the internal combustion engine 5 is in rapid acceleration will be described. When the internal combustion engine 5 accelerates rapidly, the amount of intake air sucked into the combustion chamber 14 increases rapidly, so it is estimated that condensed water present in the intake passage 20 is sucked into the combustion chamber 14. The control unit can determine whether or not the internal combustion engine 5 has accelerated rapidly based on, for example, the amount of increase in the rotational speed of the internal combustion engine 5. In this case, the storage unit stores a reference value for the amount of increase in the rotational speed of the internal combustion engine 5 in advance. The control unit acquires the amount of increase in the rotational speed of the internal combustion engine 5 (that is, the acceleration of the internal combustion engine 5) based on the rotational speed of the internal combustion engine 5 acquired based on the detection result of the crank position sensor 80, and the acquired rotational speed. Can be determined that the internal combustion engine 5 is in rapid acceleration. However, a specific method for determining whether or not the internal combustion engine 5 is in rapid acceleration by the control unit is not limited to this.

  Next, the case where the internal combustion engine 5 is started will be described. After the operation of the internal combustion engine 5 is stopped (specifically, after fuel injection is stopped and rotation of the crankshaft is stopped), moisture contained in the air in the intake passage 20 or the EGR passage 71 may be condensed. It is estimated that the condensed water generated by this condensation is sucked into the combustion chamber 14 when the internal combustion engine 5 is next started. The control unit can determine whether or not the internal combustion engine 5 has been started based on the rotational speed of the internal combustion engine 5. Specifically, the control unit can determine that the internal combustion engine 5 is in a starting state when the rotational speed of the internal combustion engine 5 changes from a zero state to a value greater than zero. However, a specific method for determining whether or not the internal combustion engine 5 is being started by the control unit is not limited to this. For example, the control unit can determine that the internal combustion engine 5 is in a starting state when a start switch for starting the internal combustion engine 5 is operated.

  As described above, when the operation state of the internal combustion engine 5 is the first operation state, that is, when the operation state of the internal combustion engine 5 is one of the operation states at the time of deceleration, sudden acceleration, and start-up, the combustion chamber 14, it is estimated that condensed water is inhaled. Therefore, by determining whether or not the condensed water suction condition is satisfied based on whether or not the internal combustion engine 5 is in the first operating state, the determination process of the condensed water suction condition can be executed with high accuracy. .

  Next, the second operating state will be described. The second operating state is a state in which the internal combustion engine 5 is operated in a state where the temperature of the refrigerant that cools the internal combustion engine 5 (hereinafter sometimes referred to as the refrigerant temperature) is lower than a predetermined temperature, or the temperature of the outside air of the internal combustion engine 5 This is a state in which the internal combustion engine 5 is operated in a state where the temperature is lower than the predetermined temperature (hereinafter sometimes referred to as the outside air temperature).

  When the refrigerant temperature is lower than the predetermined temperature, condensed water is more likely to be generated in the intake passage 20 or the EGR passage 71 of the internal combustion engine 5 than when the refrigerant temperature is not lower than the predetermined temperature. Therefore, when the internal combustion engine 5 is operated in a state where the refrigerant temperature is lower than the predetermined temperature, it is considered that the amount of condensed water generated increases, so that the condensed water is likely to be sucked into the combustion chamber 14. When the outside air temperature is lower than the predetermined temperature, condensed water is more likely to be generated in the intake passage 20 or the EGR passage 71 of the internal combustion engine 5 than when the outside air temperature is not lower than the predetermined temperature. Therefore, when the internal combustion engine 5 is operated in a state where the outside air temperature is lower than the predetermined temperature, the amount of condensed water generated increases, and as a result, there is a high possibility that the condensed water is sucked into the combustion chamber 14.

  In determining whether the refrigerant temperature is lower than the predetermined temperature, the control unit can acquire the refrigerant temperature based on the detection result of the temperature sensor. Specifically, in this case, the internal combustion engine 5 includes a temperature sensor in a refrigerant passage (for example, a water jacket formed in the cylinder block 10 or the cylinder head 11) through which the refrigerant passes. The control unit can acquire the refrigerant temperature based on the detection result of the temperature sensor.

  Or a control part can also acquire a refrigerant | coolant temperature by estimating a refrigerant | coolant temperature based on the parameter | index which has a correlation with a refrigerant | coolant temperature. As an index having a correlation with the refrigerant temperature, for example, the load of the internal combustion engine 5 (the rotational speed of the internal combustion engine 5, the fuel injection amount, the intake air amount, etc.) can be used. Further, as the predetermined temperature, an appropriate temperature is stored in the storage unit in advance, and the control unit compares the acquired refrigerant temperature with the predetermined temperature stored in the storage unit, so that the refrigerant temperature is lower than the predetermined temperature. It can be determined whether or not it is in a state.

  In determining whether or not the outside air temperature is lower than the predetermined temperature, the control unit can acquire the outside air temperature based on the detection result of the temperature sensor that detects the outside air temperature. Specifically, in this case, the internal combustion engine 5 includes a temperature sensor that detects the outside air temperature. The control unit can acquire the refrigerant temperature based on the detection result of the temperature sensor. Or a control part can also acquire outside temperature by estimating outside temperature based on the parameter | index which has a correlation with outside temperature. As an index having a correlation with the outside air temperature, for example, the temperature of the sucked air (specifically, the temperature of the air sucked into the intake passage 20), the temperature of the refrigerant, and the like can be used. Further, as the predetermined temperature, an appropriate temperature is stored in the storage unit in advance, and the control unit compares the acquired outside temperature with the predetermined temperature stored in the storage unit, so that the outside air temperature is lower than the predetermined temperature. It can be determined whether or not it is in a state.

  As described above, when the operation state of the internal combustion engine 5 is the second operation state, that is, when the operation state of the internal combustion engine 5 is the state in which the internal combustion engine 5 is operated with the refrigerant temperature lower than the predetermined temperature, or the outside air temperature In the state where the internal combustion engine 5 operates in a state where the temperature is lower than the predetermined temperature, it is considered that there is a high possibility that condensed water is sucked into the combustion chamber 14. Therefore, when the internal combustion engine 5 is in the first operation state and the second operation state, it is possible to accurately execute the determination process of the condensed water intake condition by determining that the condensed water intake condition is satisfied. it can.

  Therefore, in step S10, the control unit according to the present embodiment is in a state where the operation state of the internal combustion engine 5 corresponds to any one state of deceleration, sudden acceleration, and startup, and the refrigerant temperature is lower than a predetermined temperature. When it is determined that the internal combustion engine 5 is operating or the external air temperature is lower than a predetermined temperature and the internal combustion engine 5 is operating, the operating state of the internal combustion engine 5 is the first operating state and the first operating state. It is determined that both of the two operating states are satisfied, and it is determined that the condensed water intake condition is satisfied.

  When it is determined in step S10 that the condensate intake condition is satisfied, the control unit executes the swirl airflow strength increase control (step S20). Specifically, the control unit controls the airflow control valve 60 so that the strength of the swirling airflow formed in the combustion chamber 14 becomes stronger than before the condensed water intake condition is satisfied. Next, the control unit ends the execution of the flowchart.

  If it is not determined in step S10 that the condensate intake condition is satisfied, the control unit prohibits execution of the swirl airflow strength increase control (step S30). In this case, when the turning airflow strength increase control is not executed before step S30, the control unit does not perform the turning airflow strength increase control in step S30. On the other hand, if the swirling airflow strength increase control has already been executed before step S30, that is, if the strength of the swirling airflow has increased, the control unit decreases the strength of the swirling airflow in step S30. The intensity of the swirling airflow is returned to the intensity before execution of step S20. Next, the control unit ends the execution of the flowchart.

  If the internal combustion engine 5 is provided with a variable valve timing mechanism as the swirling airflow strength changing means, the control unit condenses the strength of the swirling airflow formed in the combustion chamber 14 when executing the swirling airflow strength increasing control. The variable valve timing mechanism is controlled to be stronger than before the water intake condition is satisfied.

  Then, the effect of the turning airflow intensity | strength increase control by the control apparatus 100 is demonstrated. FIG. 3 is a schematic perspective view for explaining the operational effect of the swirl airflow strength increase control by the control device 100. In FIG. 3, the condensed water that has passed through the intake passage 20 and is sucked into the combustion chamber 14 is blown to the inner peripheral side wall 15 of the combustion chamber 14 by the centrifugal force of the swirling airflow (specifically, the swirl flow SW). The situation is schematically illustrated. According to the control device 100 according to the present embodiment, even when the condensed water intake condition is satisfied, even if the condensed water is sucked into the combustion chamber 14, the strength is increased by the execution of the swirl airflow strength increase control. For example, the condensate sucked into the combustion chamber 14 can be blown to the inner peripheral side wall 15 of the combustion chamber 14 or discharged from the combustion chamber 14 to the exhaust passage 25 by the swirling airflow. Specifically, the condensed water that has flowed into the combustion chamber 14 is placed on a swirling airflow with increased strength and attached to the inner peripheral side wall 15 or is blown to the inner peripheral side wall 15 by the centrifugal force of the swirling airflow. It can be attached to the side wall 15. Further, the condensed water adhering to the inner peripheral side wall 15 can be discharged from the combustion chamber 14 in the exhaust stroke.

  As a result, it is possible to suppress the condensed water sucked into the combustion chamber 14 from adhering to the fuel injection valve 50 (specifically, the portion of the fuel injection valve 50 disposed in the combustion chamber 14). Thereby, corrosion of the fuel injection valve 50 due to adhering condensed water sucked into the combustion chamber 14 can be suppressed. More specifically, it is possible to suppress the condensed water sucked into the combustion chamber 14 from adhering to the nozzle 51 of the fuel injection valve 50 and corroding the peripheral portion of the nozzle hole 52, particularly the nozzle hole 52. As a result, expansion of the hole diameter of the injection hole 52 due to corrosion can be suppressed.

  In this embodiment, a swirl flow is used as the swirl airflow. However, the swirl airflow is not limited to the swirl flow as long as the swirl airflow flows along the inner peripheral side wall 15 of the combustion chamber 14. However, by using the swirl flow as the swirl airflow as in the present embodiment, the condensed water sucked into the combustion chamber 14 can be effectively blown to the inner peripheral side wall 15 by the centrifugal force of the swirl flow with increased strength. it can. As a result, corrosion of the fuel injection valve 50 caused by the condensed water sucked into the combustion chamber 14 can be effectively suppressed.

  Further, as described in step S10 in FIG. 2, the control unit according to the present embodiment condensate water when it is determined that the operation state of the internal combustion engine 5 satisfies both the first operation state and the second operation state. Although it is determined that the suction condition is satisfied, the determination as to whether or not the condensed water suction condition is satisfied is not limited to this. For example, the control unit may determine that the condensed water intake condition is satisfied when the operation state of the internal combustion engine 5 satisfies either the first operation state or the second operation state. Or a control part may use conditions other than the 1st operation state or the 2nd operation state as condensed water inhalation conditions. However, as in this embodiment, the control unit determines that the condensate intake condition is satisfied when the operation state of the internal combustion engine 5 is the first operation state and the second operation state. This is preferable in that the condition determination process can be executed with high accuracy, and as a result, the swirl airflow strength increase control can be executed accurately.

  Next, an internal combustion engine control apparatus (hereinafter referred to as a control apparatus 100a) according to Embodiment 2 of the present invention will be described. An internal combustion engine (hereinafter, referred to as an internal combustion engine 5a) to which the control device 100a according to the present embodiment is applied is a control device 100a in place of the control device 100 in the internal combustion engine 5 according to the first embodiment shown in FIG. Is different from the internal combustion engine 5 according to the first embodiment. Since the other configuration of the internal combustion engine 5a is the same as that of the internal combustion engine 5 according to the first embodiment, the description thereof is omitted and the illustration of the internal combustion engine 5a is also omitted.

  In the control device 100a according to the present embodiment, when the condensate intake condition is satisfied by the control unit, the fuel injection valve 50 is considered to be highly corroded when the condensed water adheres to the fuel injection valve 50. The embodiment relates to the first embodiment in that the swirling airflow strength increase control is executed when the corrosivity possibility condition which is the condition is satisfied, and the execution of the swirling airflow strength increase control is prohibited when the corrosion possibility condition is not satisfied. This is different from the control unit of the control device 100. Other configurations of the control device 100a are the same as those of the control device 100 according to the first embodiment.

  In the present embodiment, as the corrosion possibility condition, a condensed water amount condition that the amount of condensed water sucked into the combustion chamber 14 is a predetermined amount or more is used. That is, when the condensed water intake condition is satisfied, the control unit according to the present embodiment executes the swirling air flow strength increase control when the condensed water amount condition is further satisfied, and the condensed water intake condition is satisfied. When the water amount condition is not satisfied, execution of the swirling airflow strength increase control is prohibited.

  FIG. 4 is a diagram illustrating an example of a flowchart when the control unit of the control device 100a executes the swirling airflow strength increase control. The control unit repeatedly executes the flowchart of FIG. 4 every predetermined time. The flowchart of FIG. 4 differs from the flowchart according to the first embodiment shown in FIG. 2 in that step S15 is provided between step S10 and step S20.

  As shown in FIG. 4, the control unit of the control device 100a determines whether or not the condensed water intake condition is satisfied in step S10. Since step S10 is the same as step S10 according to the first embodiment, description thereof is omitted.

  When it is determined in step S10 that the condensed water intake condition is satisfied, the control unit determines whether or not the condensed water amount condition is satisfied (step S15). Specifically, the control unit determines whether or not the amount of condensed water sucked into the combustion chamber 14 is a predetermined amount or more. As a predetermined amount of the condensed water that is the determination criterion in step S15, for example, when the swirl airflow strength increase control is not executed, the condensed water sucked into the combustion chamber 14 is disposed in the combustion chamber 14 of the fuel injection valve 50. Of the portion (the portion exposed in the combustion chamber 14), the amount of condensed water that is considered to adhere to the nozzle 51 or the peripheral edge of the nozzle hole 52 of the nozzle 51 can be used. The amount of the condensed water can be obtained by experiments, simulations, and the like.

  In the present embodiment, as the predetermined amount of condensed water in step S15, the amount of condensed water considered to be attached to the peripheral portion of the injection hole 52 of the fuel injection valve 50 is experimentally determined as the condensed water sucked into the combustion chamber 14. The obtained value is used. This predetermined amount is stored in the storage unit. However, the specific value of the predetermined amount is not limited to this.

  In addition, there is no particular limitation on how the control unit obtains the amount of condensed water sucked into the combustion chamber 14 according to step S15. The control unit according to the present embodiment acquires the amount of condensed water sucked into the combustion chamber 14 based on an index having a correlation with the amount of condensed water sucked into the combustion chamber 14. The specific type of the index correlated with the amount of condensed water sucked into the combustion chamber 14 is not particularly limited. For example, the temperature of the exhaust passage 25, the pressure in the exhaust passage 25, the EGR rate, the internal combustion engine 5a The operation time (elapsed time from the start of the internal combustion engine 5a) or the like can be used. That is, the control unit can acquire the amount of condensed water sucked into the combustion chamber 14 based on the temperature of the exhaust passage 25, the pressure in the exhaust passage 25, the EGR rate, or the operation time of the internal combustion engine 5a.

  It is considered that the amount of condensed water accumulated in the EGR passage 71 (hereinafter sometimes referred to as condensed water accumulation amount) increases as the temperature of the exhaust passage 25 becomes lower. As a result, the amount of condensed water sucked into the combustion chamber 14 It is because it is thought that it will increase. Further, it is considered that the amount of condensed water accumulated in the EGR passage 71 increases as the pressure in the exhaust passage 25 decreases, and as a result, the amount of condensed water sucked into the combustion chamber 14 also increases. Further, it is considered that the amount of condensed water generated in the EGR passage 71 increases as the EGR rate increases, and as a result, the amount of condensed water accumulated in the EGR passage 71 also increases, and as a result, the amount of condensed water sucked into the combustion chamber 14 also increases. It is because it is thought that it will increase. Further, it is considered that the amount of condensed water accumulated in the intake passage 20 or the EGR passage 71 increases as the operation time becomes longer, and as a result, the amount of condensed water sucked into the combustion chamber 14 also increases.

  The controller uses the map to obtain the amount of condensed water sucked into the combustion chamber 14 based on the temperature of the exhaust passage 25, the pressure in the exhaust passage 25, the EGR rate, or the operation time of the internal combustion engine 5a. The amount of condensed water sucked into the chamber 14 can be acquired. Fig.5 (a)-FIG.5 (c) are schematic diagrams which show an example of the map used when a control part acquires the quantity of condensed water. Specifically, FIG. 5A shows an example of a map in which the amount of condensed water sucked into the combustion chamber 14 is defined in association with the temperature of the exhaust passage 25. FIG. 5B shows an example of a map in which the amount of condensed water sucked into the combustion chamber 14 is defined in association with the EGR rate. FIG. 5C shows an example of a map in which the amount of condensed water sucked into the combustion chamber 14 is defined in association with the operation time of the internal combustion engine 5a. The map in which the amount of condensed water sucked into the combustion chamber 14 is defined in association with the pressure in the exhaust passage 25 is a map in which the horizontal axis is replaced with the pressure in the exhaust passage 25 in FIG. Therefore, illustration is abbreviate | omitted. These maps can be obtained by experiments, simulations, and the like. The storage unit of the control device 100a stores these maps.

  For example, when the control unit acquires the amount of condensed water sucked into the combustion chamber 14 based on the temperature of the exhaust passage 25, the control unit acquires the temperature of the exhaust passage 25 and corresponds to the acquired temperature of the exhaust passage 25. The amount of condensed water to be extracted is extracted from a map as shown in FIG. In step S15, the control unit determines whether or not the amount of condensed water extracted from the map is equal to or greater than a predetermined amount stored in the storage unit.

  The control unit may acquire the temperature of the exhaust passage 25 based on a detection result of a temperature sensor that detects the temperature of the exhaust passage 25, or may acquire the temperature based on an index correlated with the temperature of the exhaust passage 25. Also good. Note that the temperature of the exhaust passage 25 may be the temperature of a pipe constituting the exhaust passage 25 (for example, the temperature of the exhaust manifold), or the temperature of the exhaust gas passing through the exhaust passage 25. When acquiring the temperature of the exhaust passage 25 based on the detection result of the temperature sensor, the internal combustion engine 5a includes a temperature sensor in the exhaust passage 25. The specific arrangement location in the exhaust passage 25 of the temperature sensor is not particularly limited. For example, a portion of the exhaust passage 25 upstream of the supercharger 40 in the exhaust flow direction and the EGR passage 71 of the exhaust passage 25 are connected. The vicinity of the location can be used. As an index having a correlation with the temperature of the exhaust passage 25, for example, the temperature of the EGR passage 71 can be used.

  When the control unit acquires the amount of condensed water sucked into the combustion chamber 14 based on the pressure in the exhaust passage 25 in step S15, the control unit acquires the pressure in the exhaust passage 25 and acquires the acquired exhaust passage. The amount of condensed water corresponding to the pressure in 25 is extracted from a map stored in the storage unit (a map in which the horizontal axis is replaced with the pressure in the exhaust passage 25 in FIG. 5A). In step S15, the control unit determines whether or not the amount of condensed water extracted from the map is equal to or greater than a predetermined amount stored in the storage unit.

  The control unit may acquire the pressure in the exhaust passage 25 based on a detection result of a pressure sensor that detects the pressure in the exhaust passage 25, or based on an index having a correlation with the pressure in the exhaust passage 25. You may get it. When acquiring the pressure in the exhaust passage 25 based on the detection result of the pressure sensor, the internal combustion engine 5 a includes a pressure sensor in the exhaust passage 25. The specific arrangement location in the exhaust passage 25 of the pressure sensor is not particularly limited, and a portion of the exhaust passage 25 upstream of the supercharger 40 in the exhaust flow direction and the EGR passage 71 of the exhaust passage 25 are connected. It is possible to use the vicinity of the portion where the head is located. As an index having a correlation with the pressure in the exhaust passage 25, for example, the load of the internal combustion engine 5 can be used.

  When the control unit acquires the amount of condensed water sucked into the combustion chamber 14 based on the EGR rate in step S15, the control unit acquires the EGR rate and sets the amount of condensed water corresponding to the acquired EGR rate. Extracted from a map as shown in FIG. 5B stored in the storage unit. In step S15, the control unit determines whether or not the amount of condensed water extracted from the map is equal to or greater than a predetermined amount stored in the storage unit. The specific method for acquiring the EGR rate by the control unit is not particularly limited. For example, the EGR rate can be acquired based on the detection result of the air flow meter and the opening degree of the EGR valve 72.

  When the control unit acquires the amount of condensed water sucked into the combustion chamber 14 based on the operation time of the internal combustion engine 5a in step S15, the control unit acquires the operation time of the internal combustion engine 5a and acquires the acquired operation time. 5 is extracted from the map as shown in FIG. 5C stored in the storage unit. In step S15, the control unit determines whether or not the amount of condensed water extracted from the map is equal to or greater than a predetermined amount stored in the storage unit. The control unit can acquire the operation time of the internal combustion engine 5a by acquiring the elapsed time from the start of the internal combustion engine 5a.

  With reference to FIG. 4, the control part which concerns on a present Example shall acquire the quantity of the condensed water suck | inhaled by the combustion chamber 14 based on the temperature of the exhaust gas mentioned above in step S15. That is, in step S15, the control unit acquires the amount of condensed water sucked into the combustion chamber 14 from the map of FIG. 5A based on the exhaust gas temperature, and the acquired amount of condensed water is stored in the memory. It is determined whether or not the condensate amount condition is satisfied by determining whether or not the predetermined amount is greater than or equal to the predetermined amount.

  When it is determined in step S15 that the amount of condensed water sucked into the combustion chamber 14 is greater than or equal to a predetermined amount, it is determined that the condensate amount condition is satisfied, and the control unit executes the swirl airflow strength increase control. (Step S20). Since the content of step S20 is the same as that of step S20 according to the first embodiment, the description thereof is omitted. After step S20, the control unit ends the execution of the flowchart.

  If it is not determined in step S10 that the condensate intake condition is satisfied, or if it is not determined in step S15 that the condensate amount condition is satisfied, the control unit prohibits execution of the swirl airflow strength increase control (step S15). S30). Since the content of step S30 is the same as that of step S30 according to the first embodiment, the description thereof is omitted. After step S30, the control unit ends the execution of the flowchart.

  Then, the effect of the control apparatus 100a which concerns on a present Example is demonstrated. First, it is considered that as the amount of condensed water sucked into the combustion chamber 14 increases, the risk of corrosion of the fuel injection valve 50 due to the condensed water sucked into the combustion chamber 14 adhering to the fuel injection valve 50 increases. On the other hand, it is possible to suppress the corrosion of the fuel injection valve 50 by suppressing the adhesion of the condensed water sucked into the combustion chamber 14 to the fuel injection valve 50 by executing the swirling airflow strength increase control. It is. However, when the swirl airflow strength increase control is executed, the discharge amount of unburned HC may increase this time.

  FIG. 6 is a diagram for explaining the relationship between the strength of the swirling airflow and the unburned HC. The vertical axis in FIG. 6 represents unburned HC (hydrocarbon exhausted without being burned in the combustion chamber 14), and the horizontal axis represents NOx contained in the exhaust. Specifically, FIG. 6 is a diagram in which the relationship between the unburned HC and the amount of NOx is experimentally obtained when the strength of the swirl flow that is the swirling airflow is relatively strong and when it is relatively weak. ing. FIG. 6 shows values measured when the temperature of the refrigerant is −7 ° C. and the temperature of the intake air is −7 ° C. and the load of the internal combustion engine 5 is low.

  As can be seen from FIG. 6, the unburned HC is generally higher in the curve when the strength of the swirl airflow is relatively stronger than the curve when the strength of the swirl airflow is relatively weak. ing. From this, it can be seen that the amount of unburned HC tends to increase as the strength of the swirling airflow increases.

  In summary, by executing the swirling airflow strength increase control, the adhesion of the condensed water sucked into the combustion chamber 14 to the fuel injection valve 50 can be suppressed and corrosion of the fuel injection valve 50 can be suppressed. This time, there is a risk that the amount of unburned HC emissions will increase. Therefore, the swirling airflow strength increase control is executed only when there is a high possibility that the fuel injection valve 50 is corroded due to adhesion of the condensed water sucked into the combustion chamber 14 to the fuel injection valve 50. It can be said that it is preferable from the viewpoint of suppressing an increase in the amount of emission.

  Therefore, it is considered that the control unit of the control device 100a according to the present embodiment is highly likely to corrode the fuel injection valve 50 when the condensed water suction condition is satisfied and the condensed water adheres to the fuel injection valve 50. When the corrosion possibility condition which is a condition is satisfied, the swirl airflow strength increase control is executed, and when the corrosion possibility condition is not satisfied, the execution of the swirl airflow strength increase control is prohibited. Specifically, the control unit uses a condensed water amount condition that the amount of condensed water sucked into the combustion chamber 14 is a predetermined amount or more as the corrosion possibility condition. When the intake condition is satisfied, the swirling air flow strength increase control is executed when the condensed water amount condition is further satisfied, and when the condensed water intake condition is not satisfied even if the condensed water intake condition is satisfied, the swirling air flow strength is increased. Execution of control is prohibited.

  Therefore, according to the control device 100a, the swirl airflow strength increase control can be executed only when the condensed water intake condition is satisfied and the condensed water amount condition is satisfied. When there is a high risk of corrosion of the fuel injection valve 50 due to adhering to the fuel injection valve 50, the control of the swirling air flow strength increase control is executed to suppress the corrosion of the fuel injection valve 50, and the risk of corrosion of the fuel injection valve 50 When is not high, an increase in the amount of unburned HC emission can be suppressed by prohibiting the execution of the swirling airflow strength increase control.

  In the present embodiment as well, the swirl flow is used as the swirling air flow as in the first embodiment. Therefore, according to the control device 100a, the fuel injection valve 50 of the fuel injection valve 50 due to the adhering condensed water sucked into the combustion chamber 14 is attached. Corrosion can be effectively suppressed.

(Modification 1)
The control device according to the present modification (hereinafter referred to as the control device 100b) has a condensate amount condition that the amount of condensed water sucked into the combustion chamber 14 is greater than or equal to a predetermined amount as a condition that the control unit may corrode. Instead, it differs from the control device 100a according to the second embodiment described above in that the condensed water pH condition that the pH of the condensed water sucked into the combustion chamber 14 is equal to or lower than the predetermined pH is used. That is, the control unit according to the present modification performs the swirl airflow strength increase control when the condensed water suction condition is satisfied, and further when the condensed water suction condition is satisfied, and when the condensed water pH condition is not satisfied. Prohibits the execution of swirl airflow strength increase control. Other configurations of the control device 100b are the same as those of the control device 100a.

  FIG. 7 is a diagram illustrating an example of a flowchart when the control unit of the control device 100b executes the swirling airflow strength increase control. The control unit repeatedly executes the flowchart of FIG. 7 every predetermined time. The flowchart of FIG. 7 differs from the flowchart of FIG. 4 in that step S16 is provided instead of step S15. The other configuration of FIG. 7 is the same as that of the flowchart of FIG.

  In step S16 of FIG. 7, the control unit of the control device 100b determines whether or not the condensed water pH condition is satisfied. Specifically, the control unit determines whether the pH of the condensed water sucked into the combustion chamber 14 is equal to or lower than a predetermined pH. The specific value of the predetermined pH of the condensed water that is the determination criterion in step S16 is not particularly limited. As the predetermined pH, for example, the value of the condensed water pH that is considered to corrode the fuel injection valve 50 when the condensed water adheres to the fuel injection valve 50 can be used. Specifically, as a predetermined pH, a value of pH that is considered to corrode a material of a portion of the fuel injection valve 50 disposed in the combustion chamber 14, more specifically, a material of the nozzle 51 of the fuel injection valve 50 is set. It is possible to use a value of pH that is considered to corrode, more specifically, a value of pH that is considered to corrode the material of the peripheral portion of the nozzle hole 52, or the like. In this modification, the value of pH that is considered to corrode the material of the nozzle 51 of the fuel injection valve 50 is used as the predetermined pH. This predetermined pH is stored in the storage unit.

  In step S16, the control unit may acquire the pH of the condensed water sucked into the combustion chamber 14 based on a detection result of a sensor (a pH sensor) that detects the pH of the condensed water. And may be acquired based on an index having a correlation. The control part which concerns on this modification acquires the pH of condensed water based on the parameter | index which has a correlation with this in step S16.

  As a specific example of this index, the EGR rate and the amount of condensed water sucked into the combustion chamber 14, or the amount of condensed water and the operation time of the internal combustion engine 5a can be used. This is because the pH of the condensed water sucked into the combustion chamber 14 is considered to be lower as the EGR rate is lower and the amount of condensed water sucked into the combustion chamber 14 is larger. This is also because the pH of the condensed water sucked into the combustion chamber 14 is considered to be lower as the amount of condensed water sucked into the combustion chamber 14 is smaller and the operation time of the internal combustion engine 5a is shorter. That is, in this case, the control unit determines whether or not the condensed water pH condition is satisfied based on the EGR rate and the amount of condensed water sucked into the combustion chamber 14 or the amount of condensed water and the operation time of the internal combustion engine 5a. It will be judged.

  In addition, when acquiring the condensed water pH based on an index having a correlation therewith in step S <b> 16, the control unit according to the present modification acquires the condensed water pH using a map. FIG. 8A and FIG. 8B are schematic diagrams illustrating an example of a map used when the control unit acquires the pH of the condensed water. Specifically, FIG. 8A shows an example of a map in which the pH of condensed water is defined in association with the EGR rate and the amount of condensed water sucked into the combustion chamber 14. More specifically, FIG. 8A shows that the condensation is such that the lower the EGR rate and the larger the amount of condensed water sucked into the combustion chamber 14, the lower the pH of the condensed water sucked into the combustion chamber 14. The pH of the water (condensed water pH) is defined in relation to the EGR rate and the amount of condensed water sucked into the combustion chamber 14.

  FIG. 8B shows an example of a map in which the pH of the condensed water is defined in association with the amount of condensed water and the operating time of the internal combustion engine 5a. Specifically, FIG. 8B shows that the condensed water sucked into the combustion chamber 14 becomes lower as the amount of condensed water sucked into the combustion chamber 14 is smaller and the operation time of the internal combustion engine 5a is shorter. In addition, the pH of the condensed water is defined in relation to the amount of condensed water and the operating time of the internal combustion engine 5a. Maps as shown in FIGS. 8A and 8B are obtained by experiments, simulations, and the like. The obtained map is stored in the storage unit.

  In step S <b> 16, for example, when the control unit acquires the pH of the condensed water sucked into the combustion chamber 14 based on the EGR rate and the amount of condensed water sucked into the combustion chamber 14, the control unit reads the EGR rate and the combustion chamber 14. The amount of condensed water sucked in is acquired, and the pH of condensed water corresponding to the acquired EGR rate and the amount of condensed water sucked into the combustion chamber 14 is extracted from a map as shown in FIG. .

  Referring to FIG. 7, the control unit according to the present modification determines whether or not the condensed water pH condition is satisfied based on the amount of condensed water and the operation time of internal combustion engine 5a in step S16. In this case, the control unit acquires the amount of condensed water sucked into the combustion chamber 14 and the operating time of the internal combustion engine 5a, and the condensed water pH corresponding to the acquired amount of condensed water and the operating time of the internal combustion engine 5a. (Condensed water pH) is extracted from a map as shown in FIG. 8B, and it is determined whether or not the extracted condensed water is equal to or lower than a predetermined pH (predetermined pH) stored in the storage unit.

  When it is determined in step S16 that the pH of the condensed water sucked into the combustion chamber 14 is equal to or lower than the predetermined pH, it is determined that the condensed water pH condition is satisfied. However, if it is not determined in step S16 that the condensed water pH condition is satisfied, the execution of the swirl airflow strength increase control is prohibited (step S30).

  As described above, also in the control device 100b according to this modification, the control unit corrodes the fuel injection valve 50 when the condensed water suction condition is satisfied and the condensed water adheres to the fuel injection valve 50. If the possibility of corrosion, a condition that is considered to be high, is satisfied, the swirling airflow strength increase control is executed. If the corrosion possibility condition is not satisfied, the swirling airflow strength increase control is prohibited. Yes. Specifically, when the condensate water intake condition is satisfied, the control unit executes the swirl airflow strength increase control when the condensate water condition is further satisfied, and when the condensate water condition is not satisfied, the control unit Execution of airflow strength increase control is prohibited.

  Here, the lower the pH of the condensed water sucked into the combustion chamber 14, the stronger the acidity of the condensed water, and as a result, the fuel injection caused by the condensed water sucked into the combustion chamber 14 adhering to the fuel injection valve 50. It is considered that the risk of corrosion of the valve 50 is increased. On the other hand, according to the control device 100b according to the present modification, the swirl airflow strength increase control can be executed only when the condensed water suction condition is satisfied and the condensed water pH condition is satisfied. When the risk of corrosion of the fuel injection valve 50 due to the condensed water sucked into the chamber 14 adhering to the fuel injection valve 50 is high, the control of the swirling airflow strength increase control is executed to suppress the corrosion of the fuel injection valve 50. When the risk of corrosion of the fuel injection valve 50 is not high, the increase in the amount of unburned HC emission can be suppressed by prohibiting the execution of the swirl airflow strength increase control.

(Modification 2)
In the control device according to this modification (hereinafter referred to as the control device 100c), the fuel injection valve 50 indicates that the temperature of the fuel injection valve 50 is equal to or lower than a predetermined temperature, instead of the condensate amount condition, as the corrosion possibility condition of the control unit. The control device 100a according to the second embodiment is different from the control device 100a in that the valve temperature condition is used. That is, when the condensate intake condition is satisfied, the control unit according to the present modification executes the swirl airflow strength increase control when the fuel injector temperature condition is further satisfied, and the fuel injector temperature condition is not satisfied. In this case, execution of the swirl airflow strength increase control is prohibited. Other configurations of the control device 100c are the same as those of the control device 100a.

  FIG. 9 is a diagram illustrating an example of a flowchart when the control unit of the control device 100c according to the present modification executes the swirl airflow strength increase control. The control unit repeatedly executes the flowchart of FIG. 9 every predetermined time. The flowchart of FIG. 9 differs from the flowchart shown in FIG. 4 in that step S17 is provided instead of step S15. The other configuration of FIG. 9 is the same as that of the flowchart of FIG.

  In step S17 of FIG. 9, the control unit of the control device 100c determines whether or not the fuel injection valve temperature condition is satisfied. Specifically, the control unit determines whether or not the temperature of the fuel injection valve 50 is equal to or lower than a predetermined temperature. The specific temperature of the fuel injection valve 50 to be used as the temperature of the fuel injection valve 50 according to step S17 is not particularly limited. As the temperature of the fuel injection valve 50, the temperature of the portion of the fuel injection valve 50 disposed in the combustion chamber 14, specifically, the temperature of the nozzle 51 of the fuel injection valve 50, more specifically, the temperature of the fuel injection valve 50. The temperature at the tip of the nozzle 51 can be used. In this modification, the temperature of the tip of the nozzle 51 of the fuel injection valve 50 is used as an example of the temperature of the fuel injection valve 50.

  The specific value of the predetermined temperature that is the determination criterion in step S17 is not particularly limited. In this modification, 100 ° C., which is the evaporation temperature of water, is used as the predetermined temperature. However, the predetermined temperature is not limited to 100 ° C. This predetermined temperature is stored in the storage unit.

  The specific acquisition method of how the control unit acquires the temperature of the tip of the nozzle 51 in step S17 is not particularly limited. The control part which concerns on this modification is acquired by estimating the temperature of the front-end | tip of the nozzle 51 based on the parameter | index which has a correlation with this. As specific examples of this index, the refrigerant temperature (refrigerant temperature) and EGR rate of the internal combustion engine 5, the refrigerant temperature, the supercharging pressure, or the like can be used. This is because the temperature at the tip of the nozzle 51 tends to increase as the refrigerant temperature increases and the EGR rate increases. Further, the higher the refrigerant temperature and the higher the supercharging pressure, the higher the temperature at the tip of the nozzle 51 tends to be. That is, in this case, in step S17, the control unit determines whether or not the fuel injection valve temperature condition is satisfied based on the refrigerant temperature and the EGR rate of the internal combustion engine 5 or the refrigerant temperature and the supercharging pressure.

  Further, the control unit according to the present modification obtains the temperature of the tip of the nozzle 51 using the map. FIGS. 10A and 10B are schematic diagrams illustrating an example of a map used when the control unit acquires the temperature of the tip of the nozzle 51 of the fuel injection valve 50. Specifically, FIG. 10A shows an example of a map in which the temperature at the tip of the nozzle 51 is defined as the temperature of the fuel injection valve 50 in association with the refrigerant temperature and the EGR rate. More specifically, FIG. 10A shows that the temperature at the tip of the nozzle 51 is related to the coolant temperature and the EGR rate so that the temperature at the tip of the nozzle 51 increases as the refrigerant temperature increases and the EGR rate increases. Has been.

  FIG. 10B shows an example of a map in which the temperature of the tip of the nozzle 51 is defined as the temperature of the fuel injection valve 50 in association with the refrigerant temperature and the supercharging pressure. More specifically, FIG. 10B shows that the temperature at the tip of the nozzle 51 is related to the refrigerant temperature and the supercharging pressure so that the temperature at the tip of the nozzle 51 increases as the refrigerant temperature increases and the supercharging pressure increases. It is prescribed. Maps as shown in FIGS. 10A and 10B are obtained in advance by experiments, simulations, etc., and stored in the storage unit.

  When the control unit acquires the temperature of the tip of the nozzle 51 of the fuel injection valve 50 based on the refrigerant temperature and the EGR rate in step S17, the control unit acquires the refrigerant temperature and the EGR rate, and the acquired refrigerant temperature and EGR rate. The temperature of the tip of the nozzle 51 corresponding to is extracted from a map as shown in FIG.

  When the control unit acquires the temperature of the tip of the nozzle 51 of the fuel injection valve 50 based on the refrigerant temperature and the supercharging pressure in step S17, the control unit acquires the refrigerant temperature and the supercharging pressure, and the acquired refrigerant temperature and The temperature at the tip of the nozzle 51 corresponding to the supercharging pressure is extracted from a map as shown in FIG.

  In addition, the specific acquisition method of the supercharging pressure by the control unit is not particularly limited. For example, the control unit can acquire the supercharging pressure based on the detection result of the pressure sensor that detects the supercharging pressure. . In this case, the internal combustion engine 5a includes a pressure sensor that detects the supercharging pressure downstream of the supercharger 40 in the intake passage 20 in the intake air flow direction, and the control unit determines the supercharging pressure based on the detection result of the pressure sensor. Just get it. Or a control part may acquire a supercharging pressure based on the parameter | index which has a correlation with a supercharging pressure. As this index, for example, exhaust pressure can be used.

  Referring to FIG. 9, in step S <b> 17, the control unit according to the present modification determines whether or not the fuel injection valve temperature condition is satisfied based on the refrigerant temperature and EGR rate of internal combustion engine 5. In this case, the control unit acquires the refrigerant temperature and the EGR rate of the internal combustion engine 5, and sets the temperature of the tip of the nozzle 51 of the fuel injection valve 50 corresponding to the acquired refrigerant temperature and the EGR rate of the internal combustion engine 5 in FIG. ), Whether the temperature of the tip of the extracted nozzle 51 is equal to or lower than a predetermined temperature stored in the storage unit, so that the fuel injection valve temperature condition is satisfied Determine whether or not.

  When it is determined in step S17 that the fuel injection valve temperature condition is satisfied, the control unit executes the swirl airflow strength increase control (step S20), and in step S17, it is not determined that the fuel injection valve temperature condition is satisfied. In this case, the execution of the swirling airflow strength increase control is prohibited (step S30).

  As described above, also in the control device 100c according to this modification, the control unit corrodes the fuel injection valve 50 when the condensed water suction condition is satisfied and the condensed water adheres to the fuel injection valve 50. If the possibility of corrosion, a condition that is considered to be high, is satisfied, the swirling airflow strength increase control is executed. If the corrosion possibility condition is not satisfied, the swirling airflow strength increase control is prohibited. Yes. Specifically, when the condensate intake condition is satisfied, the control unit executes the swirl airflow strength increase control when the fuel injection valve temperature condition is further satisfied, and when the fuel injection valve temperature condition is not satisfied. Prohibits the execution of swirl airflow strength increase control.

  Here, when the condensed water sucked into the combustion chamber 14 adheres to the fuel injection valve 50, the lower the temperature of the fuel injection valve 50, the smaller the evaporation amount of the condensed water attached to the fuel injection valve 50. The risk of corrosion of the fuel injection valve 50 due to water adhering to the fuel injection valve 50 increases. On the other hand, according to the control device 100c according to the present modification, the swirl airflow strength increase control can be executed only when the condensate intake condition is satisfied and the fuel injection valve temperature condition is satisfied. When there is a high risk of corrosion of the fuel injection valve 50 due to the condensed water sucked into the combustion chamber 14 adhering to the fuel injection valve 50, the corrosion of the fuel injection valve 50 is suppressed by executing the swirl airflow strength increase control. On the other hand, when the risk of corrosion of the fuel injection valve 50 is not high, the increase in the amount of unburned HC emission can be suppressed by prohibiting the execution of the swirl airflow strength increase control.

(Modification 3)
The control device (hereinafter referred to as the control device 100d) according to the present modification uses all of the above-mentioned condensate amount condition, condensate water condition, and fuel injection valve temperature condition as the corrosion possibility condition of the control unit. However, the control device 100a is different from the control device 100a according to the second embodiment. That is, when the condensate intake condition is satisfied, the control unit according to the present modification performs the swirling airflow intensity increase control when all of the condensate amount condition, the condensate water condition, and the fuel injection valve temperature condition are satisfied. And if any one of the condensate amount condition, the condensate pH condition, and the fuel injection valve temperature condition is not satisfied, the execution of the swirling airflow strength increase control is prohibited. The other configuration of the control device 100d is the same as that of the control device 100a.

  Since the flowchart according to this modification is a combination of the flowcharts of FIGS. 4, 7, and 9, illustration is omitted. Specifically, as a flowchart according to this modification, step S16 in FIG. 7 is added between step S15 and step S20 in the flowchart in FIG. 4, and FIG. 9 is added between the added step S16 and step S20. A flowchart in which step S17 is added can be used.

  Also in the control device 100d according to this modification, the swirl airflow strength increase control is executed when there is a high risk of corrosion of the fuel injection valve 50 due to the condensed water sucked into the combustion chamber 14 adhering to the fuel injection valve 50. Thus, while suppressing the corrosion of the fuel injection valve 50, when the risk of the corrosion of the fuel injection valve 50 is not high, the increase in the amount of unburned HC emission is suppressed by prohibiting the execution of the swirling airflow strength increase control. can do.

  Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.

DESCRIPTION OF SYMBOLS 5 Internal combustion engine 14 Combustion chamber 15 Inner peripheral wall 20 Intake passage 25 Exhaust passage 40 Supercharger 50 Fuel injection valve 60 Airflow control valve 70 EGR device 72 EGR valve 80 Crank position sensor 100 Control device

Claims (5)

  The operation state of the internal combustion engine having a fuel injection valve for directly injecting fuel into the combustion chamber and a swirling airflow strength changing means for changing the strength of the swirling airflow flowing along the inner peripheral side wall of the combustion chamber is condensed in the combustion chamber. When the condensate intake condition that the operation state in which water is estimated to be inhaled is satisfied, the strength of the swirling airflow formed in the combustion chamber is before the condensate intake condition is satisfied. A control device for an internal combustion engine, comprising: a control unit that executes a swirling airflow strength increasing control that controls the swirling airflow strength changing means so as to be stronger than the swirling airflow strength.   In the case where the condensate intake condition is satisfied, the control unit further performs the swirl airflow when the condensate amount condition that the amount of the condensed water sucked into the combustion chamber is equal to or greater than a predetermined amount is satisfied. The control device for an internal combustion engine according to claim 1, wherein strength increase control is executed, and execution of the swirl airflow strength increase control is prohibited when the condensate amount condition is not satisfied.   When the condensate water intake condition is satisfied, the control unit further turns the swivel when the condensate water condition that the pH of the condensed water sucked into the combustion chamber is equal to or lower than a predetermined pH is satisfied. The control device for an internal combustion engine according to claim 1, wherein the airflow strength increase control is executed, and the execution of the swirling airflow strength increase control is prohibited when the condensed water pH condition is not satisfied.   The control unit performs the swirling air flow strength increase control when the condensate intake condition is satisfied, and further when the fuel injection valve temperature condition that the temperature of the fuel injection valve is equal to or lower than a predetermined temperature is satisfied. 2. The control device for an internal combustion engine according to claim 1, which is executed and prohibits execution of the swirl airflow strength increase control when the fuel injection valve temperature condition is not satisfied.   The control device for an internal combustion engine according to any one of claims 1 to 4, wherein the swirling airflow is a swirl flow.

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