JP6536184B2 - Engine control device - Google Patents

Description

  The present invention relates to a control device of an engine provided with an exhaust gas recirculation device.

  An engine mounted on a vehicle or the like is often equipped with an exhaust gas recirculation device. The exhaust gas recirculation device recirculates a part of the exhaust gas exhausted from the combustion chamber of the engine to the atmosphere through the exhaust passage to the intake passage through the exhaust gas recirculation passage connecting the exhaust side and the intake side. The combustion temperature is lowered to suppress the emission of nitrogen oxides (NOx) and the like contained in the exhaust gas.

  Further, in the exhaust gas recirculation device, the temperature of the reflux gas is lowered by passing the exhaust gas (hereinafter referred to as reflux gas) to be recirculated to the intake side via a cooling device called a reflux gas cooler, and the combustion temperature is reduced. In some cases, the increase is suppressed (see, for example, Patent Document 1).

JP 2003-336549 A

  When a reflux gas cooler is provided in the exhaust gas recirculation passage, hydrocarbons, smoke and the like contained in the exhaust gas may adhere to the inside of the reflux gas cooler, and these deposits may gradually accumulate in the reflux gas cooler. If the amount of the deposit inside the reflux gas cooler is increased, not only the original cooling performance can not be exhibited, but also the amount of the reflux gas supplied to the intake passage becomes smaller than the originally set required amount. If the supply amount of the reflux gas is smaller than the required amount, the exhaust gas may not be maintained properly.

  In this respect, in the technique of Patent Document 1, the blockage of the exhaust gas recirculation passage is determined by detecting that the actual intake pressure is smaller than the normal intake pressure or the target intake pressure. However, in the case of an engine equipped with a supercharger, there is a problem that the technology of Patent Document 1 can not be used because the blockage of the exhaust gas recirculation passage and the behavior of the intake pressure resulting therefrom are different. Furthermore, if the amount of deposits in the exhaust passage and in the exhaust gas recirculation passage increases, it may lead to sticking of various movable parts such as a valve device, so there is also a demand to accurately grasp the presence or absence of these sticking.

  Therefore, an object of the present invention is to more accurately determine the blockage of the exhaust gas recirculation passage and the fixation of various movable parts such as the valve device in the exhaust gas passage and the exhaust gas recirculation passage.

  In order to solve the above-described problems, the present invention relates to a supercharger that increases an intake pressure by rotation of a turbine provided in an intake passage and an exhaust passage connected to a combustion chamber of a cylinder and a turbine provided in the exhaust passage; An exhaust gas recirculation device for introducing a part of exhaust gas into the intake air as a reflux gas through an exhaust gas recirculation passage connecting an upstream side of the turbine in the passage and the intake passage, and a recirculation gas provided in the exhaust gas recirculation passage for cooling the reflux gas Flow rate of the reflux gas passing through a reflux gas cooler, a bypass passage connecting the upstream side and the downstream side of the reflux gas cooler, or an upstream side of the reflux gas cooler and the intake passage, and a cooling device passage passing through the reflux gas cooler Flow adjustment means for adjusting the flow rate of the reflux gas passing through the bypass passage, intake pressure detection means for detecting the intake pressure introduced into the combustion chamber, and the cooling device In a state where the return gas is passing through the passage, the absolute value of the pressure difference of the reference pressure in the intake passage according to the operation condition with respect to the intake pressure detected by the intake pressure detection means is larger than a predetermined value An engine comprising: abnormality judging means for judging that there is adhesion of a member or obstruction of a passage due to deposits on any part of the exhaust passage or the exhaust gas recirculation passage when the pressure difference is a positive value; Adopted a control device.

  Here, when the abnormality determination unit determines that the abnormal state, the flow rate adjustment unit decreases the flow rate of the reflux gas passing through the cooling device passage and increases the flow rate of the reflux gas passing through the bypass passage. A configuration provided with a flow rate adjustment control unit that issues a bypass shift command can be employed.

  In addition, when the absolute value of the pressure difference of the reference pressure in the intake passage according to the operation condition with respect to the intake pressure detected by the intake pressure detection unit after the bypass transfer command is issued, The abnormality determination unit may adopt a configuration that determines that the abnormal state is due to blockage of a flow passage in the reflux gas cooler.

  The flow rate adjusting means is constituted by a bypass adjusting valve provided in the bypass passage, and after performing the bypass shift command, the flow rate adjusting means is provided in the intake passage according to the operating condition with respect to the intake pressure detected by the intake pressure detecting unit. When the absolute value of the pressure difference of the reference pressure is larger than a predetermined value, the abnormality determining unit determines that the abnormal state is a reflux gas adjusting valve provided upstream of the branch portion between the cooling device passage and the bypass passage. Or, in the case where the intake throttle valve provided in the intake passage or the supercharger includes a capacity adjusting means having movable vanes for adjusting the capacity of the turbine, a configuration is adopted in which the movable vanes are determined to be in a fixed state. Can.

  At this time, when the pressure difference after the bypass transfer command is issued is a positive value, the abnormality determination unit determines that the abnormal state indicates that the return gas adjusting valve is in the closed side fixed state or the intake throttle valve. If it is determined that the movable vane is in the closed side fixed state or the movable vane is in the closed side fixed state, and the pressure difference after the bypass transfer command is given is a negative value, the return gas adjusting valve is open side fixed It is possible to adopt a configuration in which the state or the intake throttle valve is determined to be in the closed fixed state, or the movable vane is determined to be in the open fixed state.

  According to the present invention, the reflux gas introduced from the exhaust side to the intake side through the exhaust gas recirculation passage can be selectively supplied by the cooling device passage passing through the reflux gas cooler and the bypass passage not passing through the reflux gas cooler. The flow rate of the passage can be adjusted, and the absolute value of the pressure difference of the reference pressure in the intake passage according to the operating condition with respect to the intake pressure introduced into the combustion chamber and the value of the pressure difference Alternatively, since it is possible to determine whether or not sticking of the member due to the deposit or blockage of the passage occurs in any part of the exhaust gas recirculation passage, it is possible to more accurately determine the blockage or sticking of these.

It is a schematic diagram of the engine which shows one Embodiment of this invention. It is a flowchart which shows control of the engine of this invention.

  An embodiment of the present invention will be described based on the drawings. FIG. 1 is a schematic view of an engine 1 of the present invention.

  The engine 1 of this embodiment is a diesel engine for automobiles. A piston is accommodated in a cylinder of the engine 1, and a combustion chamber 2 is formed by an inner wall surface of the cylinder, an upper surface of the piston, and the like.

  The engine 1 is provided with an intake passage 4 for feeding intake air into the combustion chamber 2 of each cylinder, an exhaust passage 5 drawn from the combustion chamber 2, and a fuel injection device 6 for injecting fuel into the combustion chamber 2.

  In the drawings, members and means directly related to the present invention are mainly shown, and other members and the like are not shown. Further, the number of cylinders of the engine is arbitrary, and may be a single cylinder, two cylinders, three cylinders, four cylinders, or multiple cylinders of more than that.

  An intake valve hole, which is an opening to the combustion chamber 2 of the intake passage 4 of each cylinder, is opened and closed by the intake valve. Further, an exhaust valve hole, which is an opening to the combustion chamber 2 of the exhaust passage 5 drawn from the combustion chamber 2, is opened and closed by the exhaust valve.

  In the intake passage 4, an intake air cooling device (intercooler) 21 for cooling intake air flowing through the intake passage 4 from the intake port leading to the combustion chamber 2 toward the upstream side, a compressor of a turbocharger that constitutes the supercharger 9, An intake throttle valve 3 for adjusting the flow passage area of the intake passage 4, an air cleaner and the like are provided. The intake throttle valve 3 adjusts the introduction amount of air (fresh air) to the intake passage 4 by increasing or decreasing the cross-sectional area of the flow passage of the intake passage 4 by the operation of the valve body of butterfly valve type.

  An exhaust gas purification device 8 provided in the exhaust passage 5 with a turbine of a turbocharger constituting the supercharger 9, a catalyst for removing harmful substances in exhaust gas, and the like from the exhaust port drawn out from the combustion chamber toward the downstream side , Mufflers, etc. are provided. In this embodiment, since the engine 1 is a diesel engine, an oxidation catalyst, a diesel particulate filter, or the like is used as the exhaust gas purification device 8. When a gasoline engine is employed as the engine 1, a three-way catalyst or the like is used as the exhaust gas purification device 8.

  In addition, the engine 1 is provided with a rotation sensor 7 that detects the number of rotations of the engine by detecting the rotational angular velocity and rotational angular acceleration of the crankshaft. In this embodiment, a crank angle sensor for reading the rotation of the timing rotor attached to the end of the crankshaft is adopted as the rotation sensor 7. However, it is driven by the rotation of the engine and the rotation of the engine. You may use the well-known rotation sensor provided in the auxiliary machine etc. which are carried out, or another place.

  These intake and exhaust valves, the fuel injection device 6, the intake throttle valve 3, the exhaust gas purification device 8 and other devices necessary for the operation of the engine are provided in an electronic control unit 30 through cables. It is controlled by the control means. Further, the electronic control unit 30 acquires necessary information from the engine and sensors provided around the engine. The electronic control unit 30 can obtain information on the number of rotations of the engine 1 and the engine load based on the information from these sensors.

  Further, the exhaust passage 5 and the intake passage 4 communicate with each other by the exhaust gas recirculation passage 11 that constitutes the exhaust gas recirculation device C. The exhaust gas recirculation device C has a function of returning a part of the exhaust gas discharged from the engine to the intake passage 4 as a return gas. The exhaust gas recirculation device C is a high pressure exhaust gas recirculation device, and the exhaust gas recirculation passage 11 is extracted from the exhaust passage 5 on the upstream side of the supercharger 9 provided in the exhaust passage 5, It is connected to the downstream side of the feeder 9.

  The exhaust gas recirculation passage 11 is provided with a reflux gas cooler 16 for reducing the temperature of the reflux gas. The reflux gas cooler 16 is provided with an air-cooled core having a space through which the reflux gas can pass, and a water-cooled core.

  The exhaust gas recirculation passage 11 on the upstream side of the reflux gas cooler 16 and the exhaust gas recirculation passage 11 on the downstream side, or the upstream side of the reflux gas cooler 16 and the intake passage 4 are connected by a bypass passage 15 not via the reflux gas cooler 16. Hereinafter, on the downstream side of the branched portion B of the bypass passage 15 in the exhaust gas recirculation passage 11, a route passing the reflux gas cooler 16 will be referred to as a cooling device passage 14 and a route not passing the reflux gas cooler 16 will be referred to as a bypass passage 15.

  Further, the exhaust gas recirculation device C is provided with a flow rate adjusting means A for adjusting the flow rate of the reflux gas passing through the cooling device passage 14 and the flow rate of the reflux gas passing through the bypass passage 15.

  In this embodiment, as the flow rate adjusting means A, a bypass adjusting valve 13 is provided in the middle of the bypass passage 15. Further, the exhaust gas recirculation passage 11 is provided, upstream of the branch portion B of the bypass passage 15 in the exhaust gas recirculation passage 11, with a reflux gas control valve 12 capable of adjusting the amount of passing gas by opening and closing the passage. The reflux gas regulating valve 12 and the bypass regulating valve 13 as the flow rate regulating means A have the function of regulating the flow rate of the reflux gas passing through the respective passages.

  The flow rate adjustment control means 31 included in the electronic control unit 30 controls the operation of the flow rate adjustment means A and the reflux gas adjustment valve 12. If the reflux gas adjustment valve 12 is closed, the introduction of the reflux gas from the exhaust side to the intake side is stopped, and if the reflux gas adjustment valve 12 is opened, the introduction of the reflux gas from the exhaust side to the intake side is started. . Further, when the bypass control valve 13 is closed, all the reflux gas passes through the cooling device passage 14, and when the bypass control valve 13 is opened, the flow rate on the bypass passage 15 increases. At this time, a large amount of reflux gas passes through the bypass passage 15 side where the resistance of the flow passage is relatively small.

  Further, an intake pressure detection means 20 for detecting an intake pressure introduced into the combustion chamber 2 is provided in the intake passage 4. A pressure sensor or the like can be employed as the intake pressure detection means 20, and the intake pressure can be detected at a position immediately before being introduced into the combustion chamber 2.

  In the supercharger 9, a turbine provided in the exhaust passage 5 is rotated by the exhaust gas discharged through the exhaust passage 5, and rotation of a turbine is transmitted to a compressor provided in the intake passage 4. The rotation of the compressor compresses the air taken in from the air cleaner and supplies the air in a supercharged state to the combustion chamber 2 of the engine 1 through the intake passage 4.

  In this embodiment, the turbine is provided with movable vanes as movable members for adjusting the flow velocity of air in the turbine.

  The movable vanes are provided along an arc-shaped scroll passage surrounding a turbine wheel in the turbine, or at an inlet portion to the scroll passage, and the movable vane swings to move in the flow direction of the scroll passage. The angle of the movable vane changes, and the change in the angle causes the cross-sectional area of the flow passage of the scroll flow passage to increase or decrease. Thereby, the size of the capacity of the turbine can be adjusted.

  Such expansion and contraction of the flow path can increase the rotational speed of the turbine wheel of the turbine with a small amount of exhaust gas mainly in a low speed region if, for example, the flow path narrows and the flow velocity increases. As a result, the output can be secured by increasing the supercharging pressure even in the low speed region and the like. In addition, when the flow path is wide, a large output can be obtained by introducing a large amount of exhaust gas into the turbine mainly in a high speed region, a high load region, and the like to increase the supercharging pressure. These controls are performed by the electronic control unit 30 according to the driving situation.

  Further, the electronic control unit 30 controls the pressure of the reference pressure in the intake passage 4 according to the operating condition with respect to the intake pressure detected by the intake pressure detection means 20 while the return flow gas is passing through the cooling device passage 14 When the absolute value of the difference is larger than a predetermined value and the pressure difference is a positive value, adhesion of a member due to deposits to any part of the exhaust passage 5 or the exhaust gas recirculation passage 11, or An abnormality determination unit 32 is provided that determines an abnormal state in which there is a blockage.

  Here, when the abnormality determination means 32 determines that the state is abnormal, the flow rate adjustment control means 31 causes the flow rate adjustment means A to decrease the flow rate of the reflux gas passing through the cooling device passage 14 and passes the bypass passage 15. And a bypass shift command to increase the flow rate of the reflux gas.

  In addition, when the absolute value of the pressure difference of the reference pressure in the intake passage 4 according to the operating condition with respect to the intake pressure detected by the intake pressure detection means 20 after the bypass transfer command is issued, The abnormality determining means 32 is configured to determine that the abnormal state is due to the blockage of the flow passage in the reflux gas cooler 16.

  In addition, when the absolute value of the pressure difference of the reference pressure in the intake passage 4 according to the operating condition with respect to the intake pressure detected by the intake pressure detection means 20 after the bypass transfer command is issued, The abnormality determining means 32 is configured to determine that the abnormal state is a state in which the return gas adjusting valve 12 or the intake throttle valve 3 or the movable vanes of the turbocharger 9 are in a fixed state.

  At this time, when the above-mentioned pressure difference after performing the bypass shift command is a positive value, the abnormality determination unit 32 determines that the abnormal state indicates that the reflux gas adjusting valve 12 is in the closed side or the intake throttle valve. It is determined that 3 is the open side fixed state or the movable vanes of the turbocharger 9 are the closed side fixed state. In addition, when the above-mentioned pressure difference after performing the bypass shift command is a negative value, the reflux gas adjustment valve 12 is in the open side fixed state, or the intake throttle valve 3 is in the closed side fixed state, or The movable vanes of the feeder 9 are determined to be in the open side fixed state.

  Hereinafter, the control method of the engine and the flow thereof will be described based on the flowchart of FIG.

  First, it is assumed that the exhaust gas recirculation device C performs open loop control (see step S1). Specifically, the opening degree of the reflux gas control valve 12 and the intake throttle valve 3 is adjusted by feedback control so that the actual intake pressure introduced into the combustion chamber 2 becomes a target value. Here, without using feedback control, it is judged whether the input has reached a predetermined target value, and the output of the process under control is not observed.

  In step S2, information on the intake pressure introduced into the combustion chamber 2 is acquired from the intake pressure detection means 20. Next, in step S3, it is determined whether the reflux gas has passed through the cooling device passage 14 via the reflux gas cooler 16. This determination can be made based on whether or not the bypass control valve 13 is closed. If the bypass control valve 13 is closed, it is determined that the reflux gas passes through the cooling device passage 14.

  When the recirculated gas passes through the cooling device passage 14, the absolute value of the pressure difference of the reference pressure of the intake air in the intake passage 4 according to the operating condition to the intake pressure detected by the intake pressure detecting means 20 is predetermined. It is determined whether it is greater than the value (see step S4).

  If the absolute value of the pressure difference between the detected intake pressure and the reference pressure is larger than a predetermined value, the process proceeds to step S6 through step S5. If the absolute value of the pressure difference between the detected intake pressure and the reference pressure is equal to or less than a predetermined value, there is no danger of sticking or blocking, so the process proceeds to step S13, and the control of the blocking / sticking determination is ended. It is determined that the absolute value of the pressure difference between the detected intake pressure and the reference pressure is larger than a predetermined value determined in this way. This is because it is considered that the introduction amount of the reflux gas does not reach the required amount or the introduction amount of the reflux gas exceeds the required amount due to the fixation of the members of the portion.

  Here, in step S5, it is determined how long the state in which the absolute value of the pressure difference between the detected intake pressure and the reference pressure is larger than a predetermined value continues before the process moves to step S6. . Since the control method of the exhaust gas recirculation device C is open loop control, the time required for the numerical value to converge on the target value is taken into consideration. The process proceeds to step S6 only when the duration exceeds a predetermined time which is predetermined as a time sufficient for the convergence of the numerical value, and since the numerical value is a transient value in the middle of control when it is less than the predetermined time. Then, the process proceeds to step S13, and the control of the blocking / sticking determination is ended.

  In step S6, it is determined whether the pressure difference between the reference pressure of the intake air in the intake passage 4 and the intake pressure detected by the intake pressure detection means 20 according to the operating condition is a positive value. If the pressure difference is a positive value, any part of the exhaust gas recirculation passage 11 may be blocked by adhesion, or a member may be stuck in any part of the exhaust gas recirculation passage 11 or the exhaust gas passage 5 It is determined to be a state, and the process proceeds to step S7.

  Therefore, in the subsequent step S7, the cause of the abnormal state is the blockage of the exhaust gas recirculation passage 11 on the side of the cooling device passage 14 by opening the bypass adjustment valve 13 and switching the introduction of the reflux gas to the bypass passage 15 via. See if it is. At this time, it is desirable that the bypass control valve 13 and the intake throttle valve 3 be fully open.

  If the pressure difference is a negative value in step S6, the return gas regulating valve 12 is stuck in the closed state, or the intake throttle valve 3 is stuck in the closed state, or the movable vane of the turbocharger 9 is Since it is judged that it is considered to be sticking (refer to step S16), it is not preferable to continue the driving as it is, so control of the blockade / sticking judgment is made through warning (step S17) to the driver by voice or display. finish.

  In step S7, after the opening of the bypass adjusting valve 13 based on the determination of the abnormal state, that is, the flow adjusting means A reduces the flow rate of the refluxing gas passing through the cooling device passage 14 and The absolute value of the pressure difference between the intake pressure detected by the intake pressure detection means 20 and the reference pressure of intake air in the intake passage 4 according to the operating condition It is determined whether it is larger than a predetermined value (see step S8).

  In step S8, when the absolute value of the pressure difference is equal to or less than the predetermined value, it is determined that the numerical value of the intake pressure approaches normal by switching the exhaust gas recirculation passage 11 to the bypass passage 15 side. Is determined to be in the cooling device passage 14 of the exhaust gas recirculation passage 11, and the process proceeds to step S10. Further, even if the absolute value of the pressure difference is larger than the predetermined value in step S8, if the continuation time exceeding the predetermined value is less than or equal to the predetermined time in step S9, similarly, It is determined that the blockade is in the cooling device passage 14 of the exhaust gas recirculation passage 11, and the process proceeds to step S10. In these cases, the abnormality is often the blockage of the flow passage in the reflux gas cooler 16. Since the detected intake pressure is larger than the reference pressure in the state before the bypass shift command, sufficient return gas is not supplied to the intake side due to the blockage of the exhaust return passage 11, and the exhaust pressure in the exhaust passage 5 It is considered that the supercharging pressure by the supercharger 9 is increased. Also, in the state after the bypass shift command, since the intake pressure approaches the appropriate numerical value, it is considered that the reflux gas adjustment valve 12 and the intake throttle valve 3 are normal, and the above cause is in the cooling device passage 14 Be

  If it is determined in step S10 that the cooling device passage 14 of the exhaust gas recirculation passage 11 is clogged, the driver is not warned by voice or display (step S11) and the reflux gas cooler 16 is not used or the exhaust gas recirculation device The operating state is shifted to the state where the introduction of the reflux gas by C is not performed (step S12). Thus, the control of the blockage / sticking determination is ended.

  Here, in step S9, it is determined how long the state in which the absolute value of the pressure difference between the detected intake pressure and the reference pressure is larger than a predetermined value lasts before the transition to step S10. . Since the control method of the exhaust gas recirculation device C is open loop control, the time required for the numerical value to converge on the target value is taken into consideration. The process proceeds to step S10 only if the duration exceeds a predetermined time which is predetermined as a time sufficient for the convergence of the numerical value, and another cause may be considered if it is the predetermined time or less, so the process proceeds to step S14.

  In the steps S8 and S9, when the absolute value of the pressure difference of the reference pressure in the intake passage 4 according to the operation condition with respect to the intake pressure detected by the intake pressure detection means 20 is larger than a predetermined value, When the time exceeds the predetermined time, the abnormal state determines that the return gas adjusting valve 12 or the intake throttle valve 3 or the movable vane of the turbocharger 9 is in the fixed state, and the process proceeds to step S14.

  In step S14, when the pressure difference after the bypass transfer command is issued is a positive value, the abnormal state is that the reflux gas adjustment valve 12 is in the close side fixed state, or the intake throttle valve 3 is in the open side fixed state, Alternatively, it is determined that the intake pressure is increased by the movable vanes of the turbocharger 9 being in the closed side fixed state. For this reason, it is not preferable to continue the driving as it is, so the control of the blockade / sticking determination is ended after the driver is warned by voice or display (step S17).

  In step S14, if the pressure difference after the bypass transfer command is issued is a negative value, the reflux gas adjustment valve 12 is in the open side fixed state, or the intake throttle valve 3 is in the closed side fixed state, or When the movable vanes of the turbocharger 9 are in the open-side fixed state, it is determined that the intake pressure is low. For this reason, it is not preferable to continue the driving as it is, so the control of the blockade / sticking determination is ended after the driver is warned by voice or display (step S17).

  In step S3, when the reflux gas does not pass through the cooling device passage 14, that is, when the bypass adjustment valve 13 is opened, the reflux gas hardly passes through the cooling device passage 14, so Moving to S7, similar control is performed.

  In the above control, regarding a predetermined value used when evaluating the absolute value of the pressure difference between the intake pressure detected by the intake pressure detection means 20 and the reference pressure of the intake in the intake passage 4 according to the operating condition, The setting of the predetermined value can be determined, for example, using a map or the like based on two factors of the engine speed and the engine load. The predetermined value tends to increase as the engine speed increases, and tends to increase as the engine load increases.

  Also, with regard to the reference pressure of intake air in the intake passage 4 according to the operating situation, the setting of this reference pressure is determined using a map or the like based on two factors, for example, the engine speed and the engine load. Can. The reference pressure tends to increase as the engine speed increases, and tends to increase as the engine load increases. The same applies to the predetermined time.

  In the above embodiment, the flow rate adjusting means A includes the reflux gas adjusting valve 12 provided on the upstream side of the branch portion B of the cooling device passage 14 and the bypass passage 15, and the bypass adjusting valve 13 provided in the bypass passage 15. However, the configuration of the flow control means A is not limited to this embodiment, and for example, a flow control valve may be provided in both the cooling device passage 14 and the bypass passage 15.

  Further, in the above embodiment, the configuration of the present invention has been described by taking a diesel engine for a car as an example, but the present invention can be applied to a gasoline engine for a car and various other engines.

Reference Signs List 1 engine 2 combustion chamber 3 intake throttle valve 4 intake passage 5 exhaust passage 6 fuel injection device 11 exhaust recirculation passage 12 recirculation gas adjustment valve 13 bypass adjustment valve 16 recirculation gas cooler 20 intake pressure detection means 30 electronic control unit (Electronic Control Unit)
31 Flow rate adjustment control means 32 Abnormality determination means A Flow rate adjustment means C Exhaust gas recirculation device

Claims (4)

An intake passage and an exhaust passage connected to a combustion chamber of the cylinder;
A turbocharger that increases the pressure of intake air by rotation of a turbine provided in the exhaust passage;
An exhaust gas recirculation device for introducing a part of the exhaust gas into the intake air as a reflux gas through an exhaust gas recirculation passage connecting the upstream side of the turbine of the exhaust passage and the intake passage;
A reflux gas cooler provided in the middle of the exhaust gas recirculation passage for cooling the reflux gas;
A bypass passage connecting an upstream side and a downstream side of the reflux gas cooler or an upstream side of the reflux gas cooler and the intake passage;
Flow rate adjustment means for adjusting the flow rate of the reflux gas passing through the cooling device passage passing through the reflux gas cooler and the flow rate of the reflux gas passing through the bypass passage;
Intake pressure detection means for detecting an intake pressure introduced into the combustion chamber;
In a state where the reflux gas passes through the cooling device passage, the absolute value of the pressure difference of the reference pressure in the intake passage according to the operating condition with respect to the intake pressure detected by the intake pressure detecting means is more than a predetermined value An abnormality determining unit that determines that there is adhesion of a member due to deposits or blockage of a passage in any part of the exhaust passage or the exhaust gas recirculation passage when the pressure difference is a large value and a positive value ;
A bypass transition command to decrease the flow rate of the reflux gas passing through the cooling device passage and increase the flow rate of the reflux gas passing through the bypass passage, when the abnormality determination means determines that there is an abnormal state. Flow regulation control means for
A control device of an engine comprising: When the absolute value of the pressure difference of the reference pressure in the intake passage according to the operation condition with respect to the intake pressure detected by the intake pressure detection means after performing the bypass shift command is the abnormality determining means, the abnormal state, the control apparatus for an engine according to judges claim 1 and is due to obstruction of the flow path in the return gas cooler. The flow rate adjusting means is constituted by a bypass adjusting valve provided in the bypass passage,
When the absolute value of the pressure difference of the reference pressure in the intake passage according to the operation condition with respect to the intake pressure detected by the intake pressure detection means after performing the bypass shift command is larger than a predetermined value, the abnormality The judging means may be a recirculation gas adjusting valve provided upstream of a branching portion between the cooling device passage and the bypass passage, an intake throttle valve provided in the intake passage, or the supercharger. The engine control device according to claim 2 , wherein the movable vanes are determined to be in the fixed state when the movable vanes are provided with a capacity adjusting means having movable vanes for adjusting the capacity of the turbine. When the pressure difference after the bypass transfer command is issued is a positive value, the abnormality determination unit determines that the abnormal state indicates that the reflux gas adjustment valve is in the closed side or the intake throttle valve is in the open state. If it is determined that the movable vane is in the closed side fixed state, and the pressure difference after the bypass transfer command is issued is a negative value, the reflux gas adjustment valve is opened in the open side fixed state or The engine control device according to claim 3 , wherein the intake throttle valve is determined to be in a closed fixed state, or the movable vane is determined as an open fixed state.

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