JP5212055B2 - Control device for internal combustion engine - Google Patents

Description

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

  Patent Document 1 discloses a technique for detecting an intake pipe pressure by closing an EGR valve at the time of fuel cut and detecting an amount of deposit deposited on the intake system.

JP-A-10-47120

  Oil for lubrication is supplied between the piston and the cylinder. This oil may be scooped up into the combustion chamber by the piston ring, and is likely to occur particularly when the intake passage has a negative pressure. The fuel cut is normally performed when the vehicle is decelerated, and the throttle valve at this time is driven to the closing side, so that the intake passage is likely to be in a negative pressure state. If the oil is pumped up when the fuel is cut, the oil may adhere to the EGR passage or the intake passage and the oil may become a binder to generate deposits.

  Accordingly, an object of the present invention is to provide a control device for an internal combustion engine that can determine whether deposits are attached to an intake system or an exhaust gas recirculation system while suppressing the generation of deposits.

  The above object is to determine whether or not deposits are attached to the exhaust gas recirculation system based on a change in the pressure value in the EGR passage by opening the EGR valve at the time of fuel cut when the fuel supply to the internal combustion engine is stopped. And an engine temperature estimating means for estimating the temperature of the internal combustion engine, and a determination prohibiting means for prohibiting the determination process by the determining means when the estimated temperature by the engine temperature estimating means is equal to or higher than a predetermined temperature. This can be achieved by a control device for an internal combustion engine.

  If the above-described determination process is performed when the engine temperature is high, oil tends to adhere to the exhaust gas recirculation system or the intake system. Oil adhering to the exhaust gas recirculation system and the intake system becomes a factor in generating deposits. However, when the engine temperature is high, the generation of deposit can be suppressed by prohibiting the determination process.

  The object is to determine whether or not deposits adhere to the intake system based on a change in the pressure value in the intake passage by closing the EGR valve at the time of fuel cut when fuel supply to the internal combustion engine is stopped. Engine temperature estimating means for estimating the temperature of the internal combustion engine; and determination prohibiting means for prohibiting determination by the determining means when the estimated temperature by the engine temperature estimating means is equal to or higher than a predetermined temperature. This can also be achieved by a control device for an internal combustion engine characterized by the above.

  In the above configuration, when the temperature estimated by the engine temperature estimation means is equal to or higher than a predetermined temperature, a configuration including low temperature control means for reducing the temperature of the engine before fuel cut can be adopted.

  By reducing the temperature of the engine before the fuel cut, it is possible to prevent oil from being scooped up to the combustion chamber side and deposits to be generated in the exhaust gas recirculation system and the intake system.

  In the above-described configuration, it is possible to employ a configuration that includes a throttle valve control unit that controls the throttle opening to the open side when the fuel is cut as the estimated temperature by the engine temperature estimation unit increases.

  By controlling the throttle opening to the open side, negative pressure in the intake system can be suppressed. This can prevent oil from adhering to the intake system side.

  In the above configuration, it is possible to employ a configuration including valve timing control means for controlling the opening / closing timing of the exhaust valve to the advance side as the estimated temperature by the engine temperature estimating means is higher before the fuel cut.

  By controlling the opening / closing timing of the exhaust valve to the advance side, the expansion ratio can be increased. Thereby, exhaust temperature can be lowered. As the exhaust temperature decreases, the engine temperature also decreases.

  In the above configuration, the apparatus includes an oil dilution amount estimation unit that detects an oil dilution amount, and the determination prohibition control unit performs the determination by the determination unit when the oil dilution amount by the oil dilution amount estimation unit is a predetermined value or more. A prohibited configuration can be adopted.

  When the amount of oil dilution is large, the oil consumption is further suppressed by prohibiting the determination process.

  In the above configuration, it is possible to employ a configuration that includes a swirl flow control valve control means that fully opens the opening of the swirl flow control valve that generates a swirl flow in the combustion chamber of the cylinder when the fuel is cut.

  The air flow in the combustion chamber can be weakened, and the oil can be prevented from splashing into the intake system.

  ADVANTAGE OF THE INVENTION According to this invention, the control apparatus of the internal combustion engine which can determine whether the deposit has adhered to the intake system or the exhaust gas recirculation system can be provided, suppressing the production | generation of a deposit.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic diagram of the engine 11. The engine 11 shown in FIG. 1 has a plurality of cylinders 12 (only one is shown in FIG. 1). In the engine 11, air flowing through the intake passage 13 is filled in the combustion chamber 15, and an air-fuel mixture is generated by the fuel injection valve 14 that directly injects fuel into the combustion chamber 15. When the air-fuel mixture is ignited by the spark plug 16, the air-fuel mixture burns, the piston 17 reciprocates, and the crankshaft 18 that is the output shaft of the engine 11 is rotationally driven. Exhaust gas generated by combustion in each combustion chamber 15 is discharged to the outside of the engine 11 through the exhaust passage 19 and the like.

  The output adjustment of the engine 11 is realized by driving a throttle valve 21 provided in the intake passage 13 by an actuator 22 or the like and adjusting the opening (throttle opening) of the throttle valve 21. The throttle opening degree is adjusted by driving the actuator 22 in accordance with the depression amount of the accelerator pedal 23 (accelerator depression amount) operated by the driver.

  The engine 11 is provided with an intake valve 24 and an exhaust valve 25 for each cylinder 12. The intake valve 24 and the exhaust valve 25 are operated by an intake cam shaft 26 and an exhaust cam shaft 27, respectively, which are rotated by transmission of the rotation of the crankshaft 18. By this operation, each intake valve 24 opens and closes a connection portion between the combustion chamber 15 and the intake passage 13, and each exhaust valve 25 opens and closes a connection portion between the combustion chamber 15 and the exhaust passage 19.

  The intake passage 13 is provided with a swirl flow control valve 30 that generates a tumble flow that is a swirl flow in the combustion chamber 15. Opening and closing of the swirl flow control valve 30 is controlled by the ECU 100. The swirl flow control valve 30 throttles the intake air that passes through the intake passage 13, so that a swirl flow is generated in the combustion chamber 15. The swirl flow control valve may be a valve that generates a swirl flow.

  In the engine 11, the intake side valve timing variable device 28 for continuously changing the operation timing of the intake valve 24 with respect to the angle (crank angle) of the crankshaft 18 and the operation timing of the exhaust valve 25 are set to the crank angle. On the other hand, an exhaust side valve timing varying device 29 for continuously changing is provided. The intake side valve timing variable device 28 and the exhaust side valve timing variable device 29 control the opening / closing timing of the intake valve 24 and the exhaust valve 25, respectively, based on a command from the ECU 100.

  The engine 11 is provided with a crank angle sensor 71 that generates a pulse signal every time the crankshaft 18 rotates by a certain angle, and an intake side cam angle sensor 72 that detects the rotation angle of the intake camshaft 26, and an exhaust camshaft An exhaust-side cam angle sensor 73 that detects the rotation angle of 27 is provided.

  An oil pan 90 is provided below the cylinder 12. Oil for lubricating the engine 11 is stored in the oil pan 90. The oil pan 90 is provided with an oil viscosity sensor 78 for detecting the viscosity of the oil and an oil temperature sensor 79 for detecting the temperature of the oil. Detection values of the oil viscosity sensor 78 and the oil temperature sensor 79 are output to the ECU 100.

  An EGR passage 80 that communicates the exhaust passage 19 and the intake passage 13 is provided. The EGR passage 80 is provided with an EGR valve 81 that opens and closes the EGR passage 80. The EGR valve 81 is controlled by the ECU 100. When the EGR valve 81 is opened, a part of the exhaust gas returns to the intake passage 13. A pressure sensor 84 is provided in the EGR passage 80. The detection value of the pressure sensor 84 is output to the ECU 100. The exhaust gas recirculation system includes an EGR passage 80 and an EGR valve 81. The intake system includes an intake passage 13, a throttle valve 21, a swirl flow control valve 30, and an intake valve 24.

  An intake pressure sensor 74 for detecting the pressure of intake air (intake pressure) is provided downstream of the throttle valve 21 in the intake passage 13. Further, an accelerator sensor 75 for detecting the amount of depression of the accelerator pedal 23 by the driver, a throttle sensor 76 for detecting the throttle opening degree, and a water temperature sensor 77 for detecting the temperature of the cooling water for cooling the engine 11 are provided. . An SOC sensor 50 that detects the remaining capacity of a battery (not shown) is provided. Further, a water pump 40 that conveys cooling water for cooling the engine 11 is provided. The water pump 40 is electric, and the water pump 40 is driven by a battery. The water pump 40 can change the output based on a command from the ECU 100.

  The ECU 100 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, and controls the operation of the entire engine 11 based on the output from each sensor. The ECU 100 executes a deposit adhesion determination process for determining deposit adhesion, as will be described in detail later. The ECU 100 corresponds to determination means, engine temperature estimation means, determination prohibition means, low temperature control means, throttle valve control means, valve timing control means, oil dilution amount estimation means, and swirl flow control valve control means.

  Further, when the ECU 100 determines that the engine operating state is decelerating based on the output from the accelerator sensor 75 or the crank angle sensor 71, the ECU 100 stops the fuel supply to the fuel injection valve 14 of the engine 11. Control, that is, fuel cut is executed.

  Next, the deposit adhesion determination process executed by the ECU 100 will be described. The deposit adhesion determination process is a process for determining whether or not deposit is adhered to the exhaust gas recirculation system. FIG. 2 is a flowchart illustrating an example of deposit adhesion determination processing executed by the ECU 100. This process is repeatedly executed every predetermined period. First, the ECU 100 acquires information related to the driving situation based on outputs from various sensors (step S1). For example, the ECU 100 acquires information such as engine temperature, engine speed, and engine load based on output values from the water temperature sensor 77, the crank angle sensor 71, the accelerator sensor 75, and the like.

  Next, the ECU 100 determines whether or not it is in a fuel cut state (step S2). If the determination is negative, the ECU 100 executes a process of step S5 described later.

  If the determination is affirmative, the ECU 100 determines whether or not the estimated engine temperature is equal to or lower than a predetermined value (step S3). The ECU 100 estimates the engine temperature based on the output from the water temperature sensor 77. The engine temperature may be estimated by a sensor that directly detects the engine wall temperature.

  If the engine temperature is less than the predetermined value, a process for determining whether or not deposits on the exhaust gas recirculation system are attached (step S4). When the engine temperature is equal to or higher than the predetermined value, ECU 100 prohibits the determination process (step S5) and ends this series of processes.

  Specifically, the process for determining whether or not deposits are attached to the exhaust gas recirculation system is performed as follows. The ECU 100 fully opens the EGR valve 81, sets the throttle valve 21 to a predetermined opening, and makes a determination based on a change in pressure value from the pressure sensor 84. Specifically, the ECU 100 maps the pressure value in the EGR passage 80 corresponding to the engine speed and the opening degree of the throttle valve 21 at the time of fuel cut, and the actual EGR passage 80 output from the pressure sensor 84. Judgment is made by comparison with the pressure value inside. This map is calculated in advance by experiments and the like, and the pressure value in the EGR passage 80 in a state where no deposit is attached to the exhaust gas recirculation system is defined. For example, when the actual pressure value is smaller than the pressure value defined by the map, it can be determined that the amount of air recirculated from the EGR passage 80 to the intake passage 13 is decreasing. Thereby, it can be determined that the deposit is attached to the EGR passage 80 or the EGR valve 81.

  The reason for determining whether or not the determination process is possible based on the engine temperature will be described. FIG. 3 is a graph showing the relationship between oil consumption and cylinder temperature. The graph of FIG. 3 shows the oil consumption measured by driving the engine with the cylinder temperature kept constant for a predetermined period. The graph of FIG. 3 shows the results for a plurality of oils having different viscosities. As shown in FIG. 3, for all oils, the higher the cylinder temperature, the greater the oil consumption. This is thought to be due to the following causes. The viscosity of the oil decreases as the oil temperature increases. As the viscosity of the oil decreases, the amount of oil scooped up by the piston ring toward the combustion chamber increases. Part of the oil pumped up to the combustion chamber side flows into the exhaust system, the intake system, or the exhaust gas recirculation system. The oil that flows to the intake system and the exhaust gas recirculation system becomes a binder, and deposits are generated. Due to the above reasons, it is considered that the oil consumption increases as the cylinder temperature increases.

  In the above processing, the reason for prohibiting the determination processing when the engine temperature is equal to or higher than the predetermined value is that if the above determination is performed under a condition where the oil consumption is likely to increase, the oil adheres to the exhaust gas recirculation system or the intake system, It is because there is a possibility that is generated.

  Therefore, by performing the determination process only when the engine temperature is lower than the predetermined value, it is possible to determine the deposit adhesion to the exhaust gas recirculation system while suppressing the generation of deposit.

  The deposit adhesion determination process is a process for determining whether or not deposit has adhered to the exhaust gas recirculation system. However, a process for determining whether or not deposit has adhered to the intake system may be performed. The determination process of deposit adhesion to the intake system is performed as follows. The ECU 100 closes the EGR valve 81, sets the throttle valve 21 to a predetermined opening degree, a map in which the intake pressure under this condition is defined, and the actual intake pressure value output from the intake pressure sensor 74 By comparing these, it can be determined whether or not deposits adhere to the intake system. For example, when the actual pressure value is smaller than the pressure value defined by the map, it can be determined that the amount of air passing through the intake passage 13 is decreasing. Thereby, it can be determined that deposits are attached to the intake passage 13 or the throttle valve 21.

  Next, a first modification of the deposit adhesion determination process executed by the ECU 100 will be described. FIG. 4 is an explanatory diagram showing an example of a first modified example of the deposit adhesion determination process executed by the ECU 100.

  The ECU 100 acquires the current driving situation from various sensors (step S21), and determines whether or not there has been a request for fuel cut (step S22). The presence / absence of a fuel cut request is determined by the output from the accelerator sensor 75. If the determination is negative, the ECU 100 prohibits the determination process (step S28b).

  If the determination is affirmative, the ECU 100 determines whether or not the output of the water pump 40 can be increased (step S23). Specifically, the ECU 100 detects the remaining capacity of the battery based on the output from the SOC sensor 50, makes an affirmative determination when the remaining capacity is greater than or equal to a predetermined value, and makes a negative determination when the remaining capacity is less than the predetermined value. To do. If the determination is negative, the ECU 100 executes the process of step S28b.

  If the determination is affirmative, the ECU 100 increases the output of the water pump 40 (step S24). Specifically, ECU 100 determines the rate of increase in the output of water pump 40 based on the map shown in FIG. FIG. 5 is a map that defines the relationship between the rate of increase in the output of the water pump 40 and the engine temperature. This map is stored in advance in the ECU 100 RAM. As shown in FIG. 5, the water pump 40 is controlled such that the rate of increase in output increases as the engine temperature increases. As the output of the water pump 40 increases, the flow rate of cooling water for cooling the engine increases, and the engine can be cooled early. Thus, the ECU 100 corresponds to a low temperature control means.

  Next, the ECU 100 determines whether or not there is a request for return from fuel cut to fuel supply (step S25). Specifically, the determination is made based on the output from the accelerator sensor 75. If the determination is affirmative, the ECU 100 prohibits the determination process (step S28a) and restores the output of the water pump 40 (step S29). If the determination is negative, the ECU 100 performs a fuel cut (step S26).

  Next, the ECU 100 determines whether or not the engine temperature is less than a predetermined value (step S27). If a negative determination is made, the processing of steps S28a and 29 is executed.

  If the determination is affirmative, the ECU 100 executes a determination process (step S28). Next, the ECU 100 returns the output of the water pump 40 to the normal state (step S29).

  As described above, by cooling the engine temperature before the determination process, when the determination process is executed, oil is scooped up to the combustion chamber side, and deposits are generated in the exhaust gas recirculation system and the intake system. Is prevented.

  Next, a second modification of the deposit adhesion determination process executed by the ECU 100 will be described. FIG. 6 is a flowchart showing an example of a second modification of the deposit adhesion determination process executed by the ECU 100. The ECU 100 executes the process of step S31 to determine the opening degree of the throttle valve 21 when the fuel is cut (step S32).

  FIG. 7 is a map that defines the relationship between the throttle opening at the time of fuel cut and the engine water temperature. This map is stored in advance in the RAM of the ECU 100. As shown in FIG. 7, the throttle opening is set to increase as the engine water temperature increases. The reason for this is that, as described above, the higher the engine temperature is, the more oil is consumed. However, it is possible to prevent the intake passage 13 from becoming a negative pressure by setting the throttle opening larger. Thereby, it is possible to prevent oil from being pumped up to the combustion chamber 15 side by the negative pressure in the intake passage 13. Thus, the ECU 100 corresponds to a throttle valve control unit that controls the opening degree of the throttle valve 21.

  Next, the ECU 100 determines whether or not the fuel is being cut (step S33). If the determination is negative, the determination process is prohibited (step S36). If the determination is affirmative, the ECU 100 determines whether the engine temperature is less than a predetermined value (step S34). If the determination is negative, the ECU 100 executes a process of step S36. If the determination is affirmative, the ECU 100 executes a determination process (step S35).

  Next, a third modification of the deposit adhesion determination process executed by the ECU 100 will be described. FIG. 8 is a flowchart illustrating an example of a third modification of the deposit adhesion determination process executed by the ECU 100. The ECU 100 acquires the current operating state (step S41) and determines the advance amount of the exhaust valve 25 (step S42).

  FIG. 9A is a graph showing the relationship between the advance amount of the exhaust valve 25 and the expansion ratio. FIG. 9B is a map that defines the relationship between the advance amount of the exhaust valve 25 and the engine temperature. This map is stored in advance in the ECU 100 RAM. As shown in FIG. 9A, the expansion ratio increases as the advance amount of the exhaust valve 25 increases, that is, as the opening / closing timing of the exhaust valve 25 is controlled to the advance side.

  Further, as shown in FIG. 9B, the ECU 100 controls the exhaust valve 25 to the advance side as the engine temperature increases. Therefore, the opening / closing timing of the exhaust valve 25 is controlled so that the expansion ratio increases as the engine temperature increases. This is because as the expansion ratio increases, the temperature of the exhaust gas decreases, and the increase in the engine temperature is suppressed. The control of the opening / closing timing of the exhaust valve 25 is performed by the ECU 100 issuing a command to the exhaust side valve timing varying device 29. Thus, ECU100 is corresponded to a valve timing control means.

  Next, the ECU 100 determines whether or not the fuel is being cut (step S43). If the determination is negative, the process of step S46 is executed. If the determination is affirmative, the ECU 100 determines whether or not the engine temperature is less than a predetermined value (step S44). If the determination is negative, the ECU 100 executes the process of step S46. If the determination is affirmative, the ECU 100 executes a determination process (step S45).

Next, a fourth modified example of the deposit adhesion determination process executed by the ECU 100 will be described. FIG. 10 is a flowchart illustrating an example of a fourth modification of the deposit adhesion determination process executed by the ECU 100.
The ECU 100 determines whether or not the oil dilution amount is equal to or greater than a predetermined value after execution of the process of step S51 (step S52). The amount of oil dilution is estimated by the following method.

  The ECU 100 acquires the current oil viscosity and oil temperature based on outputs from the oil viscosity sensor 78 and the oil temperature sensor 79. ECU 100 stores in advance a map that defines an appropriate value of oil viscosity for each oil temperature when oil dilution has not occurred. The ECU 100 can determine the oil dilution amount by reading the appropriate value of the oil viscosity according to the current oil temperature with reference to this map and comparing the appropriate value with the current oil viscosity.

  Specifically, when oil dilution occurs, the oil viscosity decreases. Therefore, when the current oil viscosity is lower than the appropriate value by a predetermined value or more, it can be determined that oil dilution has occurred. Further, the ECU 100 can estimate that the greater the difference between the appropriate value and the current oil viscosity, the greater the oil dilution amount. As described above, the ECU 100 corresponds to an oil dilution amount estimation unit.

  If the oil dilution amount is equal to or greater than the predetermined value, the ECU 100 prohibits the determination process (step S56). Thereby, it can suppress that oil is further consumed by performing determination processing. When the oil dilution amount is less than the predetermined value, ECU 100 executes the processes of steps S53 to S55.

  Next, a fifth modified example of the deposit adhesion determination process executed by the ECU 100 will be described. FIG. 11 is a flowchart illustrating an example of a fifth modification of the deposit adhesion determination process executed by the ECU 100.

  After executing the process of step S61, the ECU 100 determines whether or not the fuel is being cut (step S62). If the determination is negative, the ECU 100 executes the process of step S66. If the determination is affirmative, the ECU 100 fully opens the opening of the swirl flow control valve 30 (step S63). Thereby, the airflow in the combustion chamber can be weakened, and the oil can be prevented from being scattered in the intake system or the like. Thus, the ECU 100 corresponds to the swirl flow control valve control means. Thereafter, the ECU 100 executes the processes of steps S64 and S65.

  The embodiment described above is a preferred embodiment of the present invention. However, the present invention is not limited to this, and various modifications can be made without departing from the scope of the present invention.

FIG. 1 is a schematic diagram of an engine. FIG. 2 is a flowchart illustrating an example of deposit adhesion determination processing executed by the ECU. FIG. 3 is a graph showing the relationship between oil consumption and cylinder temperature. FIG. 4 is an explanatory diagram showing an example of a first modification of the deposit adhesion determination process executed by the ECU. FIG. 5 is a map that defines the relationship between the rate of increase in the output of the water pump and the engine temperature. FIG. 6 is a flowchart illustrating an example of a second modification of the deposit adhesion determination process executed by the ECU. FIG. 7 is a map that defines the relationship between the throttle opening at the time of fuel cut and the engine water temperature. FIG. 8 is a flowchart showing an example of a third modification of the deposit adhesion determination process executed by the ECU. FIG. 9A is a graph showing the relationship between the advance amount of the exhaust valve and the expansion ratio. FIG. 9B is a map that defines the relationship between the advance angle of the exhaust valve and the engine temperature. FIG. 10 is a flowchart showing an example of a fourth modification of the deposit adhesion determination process executed by the ECU. FIG. 11 is a flowchart illustrating an example of a fifth modification of the deposit adhesion determination process executed by the ECU.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Engine 12 Cylinder 13 Intake passage 14 Fuel injection valve 15 Combustion chamber 16 Spark plug 17 Piston 18 Crankshaft 19 Exhaust passage 21 Throttle valve 22 Actuator 23 Accelerator pedal 24 Intake valve 25 Exhaust valve 26 Intake camshaft 27 Exhaust camshaft 28 Intake side Valve timing variable device 29 Exhaust side valve timing variable device 30 Swirling flow control valve 40 Water pump 50 SOC sensor 71 Crank angle sensor 72 Intake side cam angle sensor 73 Exhaust side cam angle sensor 74 Intake pressure sensor 75 Acceleration sensor 76 Throttle sensor 77 Water temperature Sensor 78 Oil viscosity sensor 79 Oil temperature sensor 80 EGR passage 81 EGR valve 84 Pressure sensor 90 Oil pan

Claims (8)

Determining means for opening the EGR valve at the time of fuel cut when the fuel supply to the internal combustion engine is stopped and determining whether or not deposits are attached to the exhaust gas recirculation system based on a change in pressure value in the EGR passage;
Engine temperature estimating means for estimating the temperature of the internal combustion engine;
When the estimated temperature by the engine temperature estimating unit is equal to or higher than a predetermined temperature, a determination prohibiting unit that prohibits the determination process by the determining unit;
Throttle valve control means for controlling the throttle opening at the time of fuel cut to the open side as the estimated temperature by the engine temperature estimation means is higher ,
A control device for an internal combustion engine. Determining means for closing the EGR valve at the time of fuel cut when the fuel supply to the internal combustion engine is stopped and determining whether deposits are attached to the intake system based on a change in the pressure value in the intake passage;
Engine temperature estimating means for estimating the temperature of the internal combustion engine;
When the estimated temperature by the engine temperature estimating means is equal to or higher than a predetermined temperature, determination prohibiting means for prohibiting determination by the determining means;
Throttle valve control means for controlling the throttle opening at the time of fuel cut to the open side as the estimated temperature by the engine temperature estimation means is higher ,
A control device for an internal combustion engine. Determining means for opening the EGR valve at the time of fuel cut when the fuel supply to the internal combustion engine is stopped and determining whether or not deposits are attached to the exhaust gas recirculation system based on a change in pressure value in the EGR passage;
  Engine temperature estimating means for estimating the temperature of the internal combustion engine;
  When the estimated temperature by the engine temperature estimating unit is equal to or higher than a predetermined temperature, a determination prohibiting unit that prohibits the determination process by the determining unit;
  The valve timing control means for controlling the opening / closing timing of the exhaust valve to the advance side as the estimated temperature by the engine temperature estimating means is higher before the fuel cut.
  A control device for an internal combustion engine. Determining means for closing the EGR valve at the time of fuel cut when the fuel supply to the internal combustion engine is stopped and determining whether deposits are attached to the intake system based on a change in the pressure value in the intake passage;
  Engine temperature estimating means for estimating the temperature of the internal combustion engine;
  When the estimated temperature by the engine temperature estimating means is equal to or higher than a predetermined temperature, determination prohibiting means for prohibiting determination by the determining means;
  The valve timing control means for controlling the opening / closing timing of the exhaust valve to the advance side as the estimated temperature by the engine temperature estimating means is higher before the fuel cut.
  A control device for an internal combustion engine. Determining means for opening the EGR valve at the time of fuel cut when the fuel supply to the internal combustion engine is stopped and determining whether or not deposits are attached to the exhaust gas recirculation system based on a change in pressure value in the EGR passage;
  Engine temperature estimating means for estimating the temperature of the internal combustion engine;
  When the estimated temperature by the engine temperature estimating unit is equal to or higher than a predetermined temperature, a determination prohibiting unit that prohibits the determination process by the determining unit;
  An oil dilution amount estimation means for detecting the oil dilution amount;
  The control apparatus for an internal combustion engine, wherein the determination prohibition control unit prohibits the determination by the determination unit when the oil dilution amount by the oil dilution amount estimation unit is a predetermined value or more. Determining means for closing the EGR valve at the time of fuel cut when the fuel supply to the internal combustion engine is stopped and determining whether deposits are attached to the intake system based on a change in the pressure value in the intake passage;
  Engine temperature estimating means for estimating the temperature of the internal combustion engine;
  When the estimated temperature by the engine temperature estimating means is equal to or higher than a predetermined temperature, determination prohibiting means for prohibiting determination by the determining means;
  An oil dilution amount estimation means for detecting the oil dilution amount;
  The control apparatus for an internal combustion engine, wherein the determination prohibition control unit prohibits the determination by the determination unit when the oil dilution amount by the oil dilution amount estimation unit is a predetermined value or more.   Low temperature control means for lowering the temperature of the engine before fuel cut when the estimated temperature by the engine temperature estimating means is equal to or higher than a predetermined temperature,
  The control device for an internal combustion engine according to any one of claims 1 to 6.   Swirl flow control valve control means for fully opening the opening degree of the swirl flow control valve for generating swirl flow in the combustion chamber of the cylinder at the time of fuel cut,
  8. The control apparatus for an internal combustion engine according to claim 1, wherein the control apparatus is an internal combustion engine.

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