JP2014190236A - Control device of engine with supercharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively take a countermeasure to surging of a supercharger by using an air bypass valve and effectively discharge condensed water of an intercooler by using intake pressure during engine deceleration operation.SOLUTION: In an engine 1 having a supercharger 7 and an EGR device, an inlet 17b of an EGR passage 17 is connected to an exhaust passage 5 downstream of a turbine 9, and an outlet 17a is connected to an intake passage 3 upstream of a compressor 8. An intercooler 13 is provided in the intake passage 3 downstream of the compressor 8, and a water collecting part 13a is provided in the intercooler 13. A drain passage 45 is provided for draining condensed water in the water collecting part 13a to a drainage destination, and a drain valve 46 is provided for opening and closing the passage 45. An air bypass passage 41 is provided between the intake passage 3 downstream of the compressor 8 and the intake passage 3 upstream of the compressor 8, and an air bypass valve 42 is provided for opening and closing the passage 41. During deceleration operation of the engine 1, an electronic control unit 50 opens the drain valve 46 from a valve closed state and then opens the air bypass valve 42 from a valve closed state.

Description

  The present invention relates to an engine equipped with a supercharger that boosts the intake air of an engine, and includes an exhaust gas recirculation device that recirculates part of the exhaust of the engine to the engine, and controls the exhaust gas recirculation device and the like according to the operating state of the engine The present invention relates to a control device for a supercharged engine.

  Conventionally, this type of technology has been employed in, for example, automobile engines. An exhaust gas recirculation (EGR) device guides part of exhaust gas after combustion discharged from an engine combustion chamber to an exhaust passage as EGR gas to the intake passage through the EGR passage and flows through the intake passage. It is mixed with intake air and returned to the combustion chamber. EGR gas flowing through the EGR passage is adjusted by an EGR valve provided in the EGR passage. By this EGR, nitrogen oxide (NOx) in the exhaust gas can be mainly reduced, and fuel efficiency can be improved at the time of partial load of the engine.

  The engine exhaust is either free of oxygen or lean. Therefore, by mixing a part of the exhaust gas with the intake air by EGR, the oxygen concentration in the intake air decreases. For this reason, in the combustion chamber, fuel burns in a state where the oxygen concentration is low, so that the peak temperature at the time of combustion is lowered and the generation of NOx can be suppressed. In a gasoline engine, the pumping loss of the engine can be reduced even when the throttle valve is closed to some extent without increasing the oxygen content in the intake air by EGR.

  Here, recently, in order to further improve the fuel efficiency of the engine, it is conceivable to perform EGR in the entire operation region of the engine, and it is required to realize a large amount of EGR. In order to realize a large amount of EGR, it is necessary to enlarge the inner diameter of the EGR passage or increase the flow passage opening area of the valve body or the valve seat of the EGR valve as compared with the conventional technology.

  By the way, it is well known that an engine equipped with a supercharger is provided with an EGR device. The following Patent Document 1 describes an engine and an EGR device provided with this type of supercharger. This engine includes a turbocharger that includes a turbine provided in an exhaust passage and a compressor provided in an intake passage and driven by the turbine. An EGR passage is provided between the exhaust passage downstream of the turbine and the intake passage upstream of the compressor, and an EGR valve is provided in the EGR passage (low pressure loop EGR device). Further, an intercooler for cooling the intake air boosted by the compressor is provided in the intake passage downstream of the compressor. Here, in the intercooler, it is known that moisture contained in intake air or EGR gas is condensed by cooling, and the condensed water may be frozen. Therefore, a storage part for storing the condensed water is provided in the intercooler, and the condensed water stored in the storage part is discharged to the exhaust passage through the discharge passage. An open / close valve is provided in the discharge passage. When the engine is in an extremely low output operating state in which the pressure in the intercooler is lower than the pressure in the exhaust passage, and when the engine is in an operating state in the high output range, the on-off valve is electronic. The valve is closed by a control device (ECU). Therefore, when the engine is in the operating state of the extremely low output range, the on-off valve is closed, and the exhaust gas is prevented from flowing back to the intake passage through the discharge passage. On the other hand, the open / close valve is closed even when the engine is in a high power range operation state, thereby preventing inadvertent discharge of intake air. As a result, when high output is required for the engine, intake pressure is ensured, and engine output is prevented from lowering. And only when the engine is in the middle and low power range operation state, the on-off valve will be opened, and the condensed water in the intercooler will not cause engine performance deterioration or exhaust gas backflow, It is discharged well to the exhaust passage through the discharge passage.

JP 2002-303146 A

  However, in the technique described in Patent Document 1, no particular countermeasure has been taken against surging that occurs in the supercharger. Surging is a phenomenon in which the entire gas flowing through the compressor and the intake passage of the turbocharger vibrates violently in the direction of flow. When this phenomenon becomes extreme, the gas may flow backward from the outlet to the inlet of the compressor, intermittent abnormal noise may occur, or the piping of the compressor or the intake passage may vibrate.

  In addition, in the technique described in Patent Document 1, no particular contrivance has been made regarding the balance between the countermeasure for surcharge of the supercharger and the countermeasure for the condensed water of the intercooler. Here, as a countermeasure against surging, an air bypass passage may be provided between the intake passage downstream of the compressor and the intake passage upstream of the compressor, and an air bypass valve may be provided in the air bypass passage. When the engine provided with a throttle valve in the intake passage is decelerated, the air bypass valve is opened to reduce the intake passage downstream of the compressor as a countermeasure against surging. . On the other hand, in order to discharge condensed water, the on-off valve is opened in the middle and low output range. However, if the air bypass valve is open at this time, the pressure on the inlet side of the discharge passage cannot be made higher than the pressure on the outlet side of the passage, and depending on the conditions, it is necessary for discharging condensed water. The pressure difference cannot be secured. In particular, in the case of an EGR device that assumes a large amount of EGR, the amount of condensed water that accumulates in the intercooler due to the passage of EGR gas increases, so it becomes more important to ensure the opportunity to discharge condensed water.

  The present invention has been made in view of the above circumstances, and an object thereof is to effectively take measures against surcharge of a supercharger using an air bypass valve and to utilize intake pressure during engine deceleration operation. An object of the present invention is to provide a control device for an engine with a supercharger that can effectively discharge condensed water in an intercooler.

  In order to achieve the above object, an invention according to claim 1 is provided between an intake passage and an exhaust passage of an engine, and a supercharger for boosting intake air in the intake passage, and a supercharger, A compressor disposed in the intake passage, a turbine disposed in the exhaust passage, a rotating shaft that connects the compressor and the turbine so as to be integrally rotatable, and an exhaust gas discharged from the combustion chamber of the engine to the exhaust passage. An exhaust gas recirculation device including an exhaust gas recirculation passage for flowing the exhaust gas as an exhaust gas recirculation gas into the intake passage and recirculating to the combustion chamber, an exhaust gas recirculation valve for adjusting the exhaust gas recirculation gas in the exhaust gas recirculation passage, An intake air amount adjustment valve for adjusting the intake air amount in the intake passage and that the inlet is connected to the exhaust passage downstream of the turbine and the outlet is connected to the intake passage upstream of the compressor The intercooler is provided in the intake passage downstream of the compressor and upstream of the intake air amount adjustment valve for cooling the intake air boosted by the supercharger, and the intercooler collects condensed water in the intercooler. A drainage passage for discharging the condensed water collected in the catchment portion to a discharge destination having a lower pressure than the catchment portion, a drainage valve for opening and closing the drainage passage, and an intake air downstream from the compressor An air bypass passage that bypasses between the passage and the intake passage upstream of the compressor, an air bypass valve that opens and closes the air bypass passage, and an operating state detection means that detects the operating state of the engine are detected. The control means for controlling at least the exhaust gas recirculation valve, the drain valve and the air bypass valve based on the operating state and the intake air amount adjusting valve are used during engine acceleration operation or steady state. In a control device for an engine with a supercharger, which is opened when the engine is stopped and closed when the engine is stopped or decelerated, the control means removes the drain valve from the closed state when the engine decelerates. The purpose is to open the air bypass valve from the closed state simultaneously with or after the drain valve is opened.

  According to the configuration of the above invention, in the intercooler, moisture contained in the intake air or the exhaust gas recirculation gas may be condensed by cooling, and the condensed water is once collected in the water collecting section. And when the pressure around the water collection part is higher than the pressure around the discharge destination of the condensed water, the drain valve is opened, so that the condensed water in the water collection part passes through the drain passage. It is discharged to the discharge destination. Here, for example, when the engine is decelerating, the intake air amount adjustment valve is closed, so that the intake pressure in the intake passage upstream from the intake air amount adjustment valve is increased, and the pressure around the water collection portion is increased around the discharge destination. Higher than pressure. On the other hand, if the intake pressure in the intake passage upstream from the intake air amount adjustment valve, that is, the intake passage downstream from the compressor, suddenly increases, surging may occur in the turbocharger. This surging can be suppressed by opening the air bypass valve and releasing the intake pressure to the intake passage upstream of the compressor when the intake pressure suddenly increases. However, when the engine is decelerating, opening the air bypass valve to release the intake air pressure is effective for surging the turbocharger, but the pressure between the area around the water collection section and the area around the discharge destination. It is disadvantageous in ensuring the difference. According to the configuration of the above invention, the drain valve is opened from the closed state by the control means during the deceleration operation of the engine, and the air bypass valve is opened from the closed state simultaneously with or after the drain valve is opened. The Therefore, since the drain valve is opened at the same time or before the air bypass valve is opened, the drain valve is kept in a state in which the pressure difference between the periphery of the water collecting portion and the periphery of the discharge destination is maintained. It will be opened.

  In order to achieve the above object, according to a second aspect of the present invention, in the first aspect of the present invention, the operating state detection means includes a cooling water temperature detection means for detecting the temperature of the engine cooling water, and an outside air. Outside air temperature detecting means for detecting the temperature of the engine, and the control means determines whether or not the condensed water in the intercooler is frozen based on the detected temperature of the cooling water and the temperature of the outside air, respectively. However, it is intended that the drain valve is allowed to open when it is determined that the condensed water is not frozen.

  According to the configuration of the above invention, in addition to the operation of the invention according to claim 1, whether or not the condensed water in the intercooler is frozen by the control means based on the temperature of the engine cooling water and the temperature of the outside air. Is determined, and when it is determined that the condensed water is not frozen, the drain valve is allowed to open. Therefore, when the condensed water is frozen, the drain valve is not allowed to open, and the drain valve is not opened unnecessarily.

  In order to achieve the above object, according to a third aspect of the present invention, in the first or second aspect of the present invention, the control means determines the amount of condensed water in the water collecting section based on the detection result of the operating state detection means. The purpose is to allow the drainage valve to open when the estimation result reaches a predetermined specified amount.

  According to the configuration of the invention, in addition to the operation of the invention according to claim 1 or 2, when the amount of condensed water in the water collecting section is estimated by the control means, and the estimation result becomes a predetermined specified amount. In addition, the drain valve is allowed to open. Therefore, when the condensate in the water collection part is not the specified amount, that is, when the condensate does not accumulate in the water collection part, the drain valve is not allowed to open, and the drain valve is opened wastefully. There is nothing to do.

  In order to achieve the above object, according to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the control means uses the condensed water in the water collecting section based on the detection result of the operating state detection means. The exhaust gas recirculation valve is forcibly fully closed when the estimated result reaches a predetermined specified amount.

  According to the configuration of the above invention, in addition to the operation of the invention according to any one of claims 1 to 3, the amount of condensed water in the water collecting section is estimated by the control means based on the operating state of the engine. When the estimation result reaches a predetermined specified amount, the exhaust gas recirculation valve is forcibly fully closed by the control means. Therefore, when the amount of condensed water in the water collecting section reaches a specified amount, the flow of exhaust gas recirculation gas into the intake passage is blocked, so that generation of condensed water in the intercooler can be suppressed.

  According to the first aspect of the present invention, it is possible to effectively take measures against surcharge of the supercharger using the air bypass valve, and to condense in the intercooler using the intake air pressure during the deceleration operation of the engine. Water can be discharged efficiently to the discharge destination at once, and stagnation of condensed water in the drainage passage can be prevented.

  According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, it is possible to determine whether or not the condensed water is frozen without using a dedicated temperature sensor. The operating frequency of the valve can be reduced, and the durability of the drain valve can be improved.

  According to the invention of claim 3, in addition to the effect of the invention of claim 1 or 2, whether or not the water collecting part is full of condensed water without using a dedicated sensor such as a water level sensor. Can be determined, the frequency of operation of the drain valve can be reduced, and the durability of the drain valve can be improved.

  According to the invention described in claim 4, in addition to the effect of the invention described in any one of claims 1 to 3, the water collecting part is filled with condensed water, and the condensed water overflows from the water collecting part. It is possible to prevent the condensed water from being inadvertently sucked into the combustion chamber.

1 is a schematic configuration diagram showing an engine system according to a first embodiment and including an exhaust gas recirculation device (EGR device) for an engine with a supercharger. The schematic which shows the relationship between an intake passage and an intercooler according to the embodiment. The flowchart which shows an example of the processing content of condensate discharge control concerning the embodiment. The map referred in order to obtain | require ABV valve opening time according to the embodiment. The map referred in order to obtain | require the drain valve opening time concerning the embodiment. The time chart which shows an example of the behavior of the various parameters regarding the condensed water discharge control concerning the embodiment. The flowchart which concerns on 2nd Embodiment and shows an example of the processing content of condensed water discharge | emission control. The flowchart which shows an example of the thawing | decompression determination process for setting the condensed water thawing | decompression flag concerning the embodiment. The map referred to in order to obtain | require a 1st integrated intake air amount concerning the embodiment. The flowchart which concerns on 3rd Embodiment and shows an example of the processing content of condensed water discharge | emission control. The flowchart which shows an example of the fullness determination process of condensed water concerning the embodiment. The map referred in order to obtain | require a condensed water count value according to the embodiment. The map referred in order to obtain | require a condensed water count value according to the embodiment. The map referred in order to obtain | require a condensed water count value according to the embodiment. The map referred in order to obtain | require a condensed water count value according to the embodiment. The map referred in order to obtain | require a condensed water count value according to the embodiment. The map referred in order to obtain | require a condensed water count value according to the embodiment. The flowchart which shows an example of the processing content of forced EGR cut determination concerning the embodiment. The flowchart which shows an example of the processing content of forced EGR cut control concerning the embodiment. The time chart which shows an example of the behavior of the various parameters regarding the said various control concerning the embodiment.

<First Embodiment>
Hereinafter, a first embodiment of a control device for a supercharged engine according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic configuration diagram showing an engine system including an exhaust gas recirculation device (EGR device) for an engine with a supercharger in this embodiment. This engine system includes a reciprocating engine 1. An intake passage 3 is connected to the intake port 2 of the engine 1, and an exhaust passage 5 is connected to the exhaust port 4. An air cleaner 6 is provided at the inlet of the intake passage 3. A supercharger 7 for boosting the intake air in the intake passage 3 is provided in the intake passage 3 downstream of the air cleaner 6 between the exhaust passage 5 and the intake passage 3.

  The supercharger 7 includes a compressor 8 disposed in the intake passage 3, a turbine 9 disposed in the exhaust passage 5, and a rotating shaft 10 that connects the compressor 8 and the turbine 9 so as to be integrally rotatable. The supercharger 7 rotates the turbine 9 by the exhaust gas flowing through the exhaust passage 5 and integrally rotates the compressor 8 via the rotating shaft 10 to increase the intake air in the intake passage 3 by the supercharging pressure. Supercharge is to be done.

  An exhaust bypass passage 11 that bypasses the turbine 9 is provided in the exhaust passage 5 adjacent to the supercharger 7. A waste gate valve 12 is provided in the exhaust bypass passage 11. By adjusting the exhaust gas flowing through the exhaust bypass passage 11 by the waste gate valve 12, the exhaust gas flow rate supplied to the turbine 9 is adjusted, the rotational speeds of the turbine 9 and the compressor 8 are adjusted, and supercharging by the supercharger 7 is performed. The pressure is adjusted.

  A surge tank 3 a is provided in the intake passage 3 upstream from the intake port 2. The intake passage 3 upstream of the surge tank 3a is provided with an electronic throttle device 14 that is an electric throttle valve. The electronic throttle device 14 corresponding to the intake air amount adjusting valve of the present invention includes a butterfly throttle valve 21 disposed in the intake passage 3, a step motor 22 for opening and closing the throttle valve 21, And a throttle sensor 23 for detecting an opening (throttle opening) TA. The electronic throttle device 14 is configured such that the throttle valve 21 is opened and closed by a step motor 22 in accordance with the operation of an accelerator pedal 26 by a driver, and the opening degree thereof is adjusted. As the configuration of the electronic throttle device 14, for example, the basic configuration of the “throttle device” described in FIGS. 1 and 2 of JP 2011-252482 A can be employed. The exhaust passage 5 downstream from the turbine 9 is provided with a catalytic converter 15 as an exhaust catalyst for purifying exhaust.

  An intercooler 13 is provided in the intake passage 3 downstream of the compressor 8 and upstream of the electronic throttle device 14. The intercooler 13 is for cooling the intake air that has been pressurized by the compressor 8 (supercharger 7) to a high temperature.

  The engine 1 is provided with an injector 25 for injecting and supplying fuel to the combustion chamber 16. Fuel is supplied to the injector 25 from a fuel tank (not shown). The engine 1 is provided with a spark plug 29 corresponding to each cylinder. Each spark plug 29 is ignited by receiving a high voltage output from the igniter 30. The ignition timing of each spark plug 29 is determined by the high voltage output timing from the igniter 30.

  In this embodiment, the EGR device for realizing a large amount of EGR causes a part of the exhaust discharged from the combustion chamber 16 of the engine 1 to the exhaust passage 5 to flow into the intake passage 3 as EGR gas and to be returned to the combustion chamber 16. An exhaust gas recirculation passage (EGR passage) 17 and an exhaust gas recirculation valve (EGR valve) 18 provided in the EGR passage 17 for adjusting the flow of EGR gas in the EGR passage 17 are provided. The EGR passage 17 is provided between the exhaust passage 5 downstream from the catalytic converter 15 and the intake passage 3 upstream from the compressor 8. That is, in order to flow part of the exhaust gas flowing through the exhaust passage 5 as EGR gas to the intake passage 3 through the EGR passage 17 and return to the combustion chamber 16, the outlet 17 a of the EGR passage 17 is connected to the intake passage 3 upstream of the compressor 8. Connected to. Further, the inlet 17 b of the EGR passage 17 is connected to the exhaust passage 5 downstream from the catalytic converter 15. The EGR passage 17 is provided with an EGR cooler 20 for cooling the EGR gas flowing through the passage 17. In this embodiment, the EGR valve 18 is disposed in the EGR passage 17 upstream of the EGR cooler 20.

  As shown in FIG. 1, the EGR valve 18 is configured as a poppet valve and as an electric valve. That is, the EGR valve 18 includes a valve body 32 that is driven by the step motor 31. The valve body 32 has a substantially conical shape, and is provided so as to be seated on a valve seat 33 provided in the EGR passage 17. The step motor 31 includes an output shaft 34 that is configured to be capable of linearly reciprocating (stroke), and a valve body 32 is fixed to the tip of the output shaft 34. The output shaft 34 is supported by a housing constituting the EGR passage 17 via a bearing 35. The opening degree of the valve body 32 relative to the valve seat 33 is adjusted by moving the output shaft 34 of the step motor 31 by a stroke. The output shaft 34 of the EGR valve 18 is provided so as to be able to perform a stroke movement by a predetermined stroke from a fully closed state in which the valve body 32 is seated on the valve seat 33 to a fully open state in which the valve body 32 contacts the bearing 35. In this embodiment, in order to realize a large amount of EGR, the opening area of the valve seat 33 is enlarged as compared with the conventional technique. Accordingly, the valve body 32 is enlarged. As a configuration of the EGR valve 18, for example, a basic configuration of “EGR valve” described in FIG. 1 of JP 2010-275941 A can be adopted.

  In this embodiment, as a countermeasure against surging generated in the compressor 8 of the supercharger 7, as shown in FIG. 1, the intake passage 3 upstream from the intercooler 13 and downstream from the compressor 8 and the intake air upstream from the compressor 8 are used. An air bypass passage 41 that bypasses the passage 3 is provided. The air bypass passage 41 is provided with an air bypass valve (ABV) 42 for opening and closing the passage 41. ABV42 is comprised as an electromagnetic valve which opens and closes a valve body with a solenoid. When the engine 1 with the electronic throttle device 14 (throttle valve 21) closed is decelerated, the ABV 42 is used to depressurize the intake passage 3 downstream from the compressor 8 as a countermeasure against surging of the supercharger 7. The valve will be opened.

  Here, in the intercooler 13, the water contained in the intake air and the EGR gas passing through the intercooler 13 may be condensed by cooling, and the condensed water may be frozen. Therefore, the engine system of this embodiment is provided with a condensed water treatment device for treating the condensed water in the intercooler 13. FIG. 2 schematically shows the relationship between the intake passage 3 and the intercooler 13. As shown in FIGS. 1 and 2, the condensed water treatment apparatus is provided in the intercooler 13, and collects the condensed water collected in the collected water portion 13 a and the collected water portion 13 a for collecting condensed water in the intercooler 13. A drainage passage 45 for discharging to a discharge destination having a lower pressure than the water collecting section 13a, a drainage valve 46 for opening and closing the passage 45, and a drainage passage 45 for opening and closing the passage 45, and condensed water And a check valve 47 for preventing the backflow of the air. The drain valve 46 is configured as an electromagnetic valve that opens and closes a valve body by a solenoid. In this embodiment, the drainage passage 45, the drainage valve 46, and the check valve 47 are arranged at positions where they are easily subjected to heat generation of the engine 1 in order to prevent them from freezing.

  In this embodiment, as shown in FIG. 2, the intercooler 13 is attached to the intake passage 3 so as to be slightly inclined with respect to the horizontal. The intercooler 13 is inclined so as to be lowered in the direction in which the intake air flows. The condensed water collecting portion 13a is disposed at the lowermost position on the downstream side of the intercooler 13 (the lowest position of the inclination), and the condensed water WA that flows down due to gravity is collected. As shown in FIG. 1, in this embodiment, the outlet 45 a of the drainage passage 45 is connected to the EGR passage 17 in the vicinity of the exhaust passage 5 and upstream of the EGR valve 18. The connection position of the outlet 45a is a condensed water discharge destination. Exhaust pressure in the exhaust passage 5 downstream from the catalytic converter 15 acts on the outlet 45a.

  In this embodiment, in order to execute fuel injection control, ignition timing control, intake air amount control, EGR control, condensed water discharge control, and the like according to the operating state of the engine 1, the injector 25, the igniter 30, and the electronic throttle device 14 are executed. The step motor 22, the step motor 31 of the EGR valve 18, the ABV 42, and the drain valve 46 are controlled by an electronic control unit (ECU) 50 according to the operating state of the engine 1. The ECU 50 stores in advance a central processing unit (CPU), a predetermined control program and the like, various memories for temporarily storing a calculation result of the CPU, and the like, an external input circuit connected to these parts, and an external And an output circuit. The ECU 50 corresponds to an example of a control unit of the present invention. The external output circuit is connected to an igniter 30, an injector 25, step motors 22 and 31, an ABV 42 and a drain valve 46. Various sensors 27 and 51 to 57 corresponding to an example of the operation state detecting means of the present invention for detecting the operation state of the engine 1 including the throttle sensor 23 are connected to the external input circuit, and various engine signals are inputted. It has become so.

  Here, in addition to the throttle sensor 23, various sensors include an accelerator sensor 27, an intake pressure sensor 51, a rotation speed sensor 52, a water temperature sensor 53, an air flow meter 54, an air-fuel ratio sensor 55, an outside air temperature sensor 56, and an intercooler outlet temperature. A sensor 57 is provided. The accelerator sensor 27 detects an accelerator opening ACC that is an operation amount of the accelerator pedal 26. The accelerator pedal 26 corresponds to an operating means for operating the operation of the engine 1. The intake pressure sensor 51 detects the intake pressure PM in the surge tank 3a. That is, the intake pressure sensor 51 detects the intake pressure PM in the intake passage 3 (surge tank 3a) downstream from the position where EGR gas flows from the EGR passage 17 into the intake passage 3. The rotational speed sensor 52 detects the rotational angle (crank angle) of the crankshaft 1a of the engine 1 and detects the change in the crank angle as the rotational speed (engine rotational speed) NE of the engine 1. The water temperature sensor 53 detects the temperature (cooling water temperature) THW of the cooling water of the engine 1 and corresponds to the cooling water temperature detecting means of the present invention. The air flow meter 54 detects the intake air amount Ga flowing through the intake passage 3 immediately downstream of the air cleaner 6. The air-fuel ratio sensor 55 is provided in the exhaust passage 5 immediately upstream of the catalytic converter 15, and detects the air-fuel ratio A / F in the exhaust. The outside air temperature sensor 56 is provided in the air cleaner 6 and detects the temperature (outside air temperature) THA of the outside air sucked into the intake passage 3 and corresponds to the outside air temperature detecting means of the present invention. The intercooler outlet temperature sensor 57 detects the temperature of intake air (intercooler outlet temperature) THIO at the outlet of the intercooler 13.

  In this embodiment, the ECU 50 controls the EGR valve 18 in order to execute EGR control in accordance with the operation state of the engine 1 in the entire operation region of the engine 1. Further, the ECU 50 controls the electronic throttle device 14 in order to execute intake air amount control according to the operating state of the engine 1. That is, the ECU 50 controls the electronic throttle device 14 so that the throttle valve 21 is opened during acceleration or steady operation of the engine 1 and closed when the engine 1 is stopped or decelerated. It has become.

  In this embodiment, the ECU 50 controls the ABV 42 and the drain valve 46 in order to execute the condensed water discharge control according to the operating state of the engine 1. FIG. 3 is a flowchart showing an example of the processing content of the condensed water discharge control.

  When the processing shifts to this routine, first, at step 100, the ECU 50 takes in the engine rotational speed NE and the engine load KL. Here, the ECU 50 can determine the engine load KL from the relationship between the engine rotational speed NE and the intake air amount Ga or the intake pressure PM.

  Next, in step 101, the ECU 50 determines whether or not the engine 1 is in a deceleration operation. If this determination result is negative, the ECU 50 proceeds to step 115, and if this determination result is affirmative, the ECU 50 proceeds to step 102.

  In step 115, the ECU 50 closes the ABV 42 and sets the ABV valve opening flag XABV to “0”. The flag XABV is set to “1” when the ABV 42 is opened and to “0” when the valve is closed. Next, at step 116, the ECU 50 closes the drain valve 46 and sets the drain valve open flag XDRV to “0”. This flag XDRV is set to “1” when the drain valve 46 is opened and to “0” when the drain valve 46 is closed. Further, in step 117, the ECU 50 resets the post-deceleration time Tdown to “0”. Thereafter, the ECU 50 returns the process to step 100.

  On the other hand, in step 102, the ECU 50 obtains the ABV valve opening time Tabv and the drain valve opening time Tdrv based on the engine speed NE and engine load KL immediately before deceleration. The ECU 50 can obtain the ABV valve opening time Tabv according to the engine rotational speed NE and the engine load KL, for example, by referring to a map as shown in FIG. Further, the ECU 50 can obtain the drain valve opening time Tdrv according to the engine rotational speed NE and the engine load KL, for example, by referring to a map as shown in FIG. 4 and 5 are set such that the drain valve opening time Tdrv and the ABV valve opening time Tabv increase as the engine speed NE and engine load KL immediately before deceleration increase.

  Next, in step 103, the ECU 50 obtains a post-deceleration time Tdown that is an elapsed time after the engine 1 starts decelerating operation.

  Next, in step 104, the ECU 50 determines whether or not the drain valve opening flag XDRV is “0”, that is, whether or not the drain valve 46 is closed. If this determination result is affirmative, the ECU 50 proceeds to step 105, and if this determination result is negative, the ECU 50 proceeds to step 106.

  In step 105, the ECU 50 opens the drain valve 46 and sets the drain valve open flag XDRV to “1”. Thereby, condensed water is discharged | emitted from the water collection part 13a. Thereafter, the ECU 50 proceeds to step 109.

  On the other hand, in step 106, the ECU 50 takes in the drain valve opening time Tdrv obtained in step 102. Subsequently, in step 107, the ECU 50 waits for the post-deceleration time Tdown to become greater than the drain valve opening time Tdrv. In step 108, the ECU 50 closes the drain valve 46 and sets the drain valve open flag XDRV to “0”. To "". Thereby, discharge of the condensed water from the water collection part 13a is stopped. Thereafter, the ECU 50 proceeds to step 109.

  In step 109 after shifting from step 105 or step 108, the ECU 50 determines whether or not the ABV valve opening flag XABV is “0”, that is, whether or not the ABV 42 is closed. If this determination result is affirmative, the ECU 50 proceeds to step 110. If this determination result is negative, the ECU 50 proceeds to step 112.

  In step 110, the ECU 50 waits for the post-deceleration time Tdown to be longer than the predetermined reference time A. In step 111, the ECU 50 opens the ABV 42 and sets the ABV valve opening flag XABV to “1”. As a result, the intake pressure downstream of the compressor 8 is released upstream of the compressor 8 through the air bypass passage 41. Thereafter, the ECU 50 returns the process to step 100. Here, the relationship between the reference time A, the drain valve opening time Tdrv, and the ABV valve opening time Tabv is “A <Tdrv ≦ Tabv”.

  On the other hand, in step 112, the ECU 50 takes in the ABV valve opening time Tabv. Subsequently, in step 113, the ECU 50 waits for the post-deceleration time Tdown to become larger than the ABV valve opening time Tabv, and in step 114, closes the ABV 42 and sets the ABV valve opening flag XABV to “0”. . Thereby, the relief of the intake pressure downstream from the compressor 8 is completed. Thereafter, the ECU 50 returns the process to step 100.

  According to the above control, the ECU 50 opens the drain valve 46 from the closed state during the deceleration operation of the engine 1, and after a while, opens the ABV 42 from the closed state. . Further, the ECU 50 obtains the ABV valve opening time Tabv and the drain valve opening time Tdrv according to the operating state (engine rotational speed NE, engine load KL) immediately before the deceleration. When the elapsed time after deceleration (time Tdown after deceleration) of the engine 1 becomes longer than the drain valve opening time Tdrv, the drain valve 46 opened is closed. Similarly, when the elapsed time after deceleration (time Tdown after deceleration) of the engine 1 becomes larger than the ABV valve opening time Tabv, the opened ABV 42 is closed.

  Here, FIG. 6 shows an example of behavior of various parameters related to the above control in a time chart. 6A shows the behavior of the throttle opening TA and the engine speed NE, FIG. 6C shows the behavior of the post-deceleration time Tdown, FIG. 6D shows the behavior of the drain valve 46, and FIG. Figure (e) shows the behavior of ABV42. 6B shows the intake pressure PM (pressure in the surge tank 3a downstream of the throttle valve 21), and the throttle valve upstream intake pressure PMtac (when the drain valve 46 and the ABV 42 are not opened). (Supercharging pressure) and throttle valve upstream intake pressure PMtao (supercharging pressure) when the drain valve 46 and the ABV 42 are opened.

  In FIG. 6, before time t1, as shown in FIG. 6 (a), the throttle opening degree TA is in a steady operation at a predetermined opening degree, and as shown in FIG. 6 (b). The intake pressure PM and the throttle valve upstream side intake pressure PMtac, PMtao are above atmospheric pressure. Then, as shown in FIG. 6A, when the throttle opening TA falls toward the idle opening at time t1, and the deceleration operation of the engine 1 is started, the deceleration is performed as shown in FIG. 6C. The count of the later time Tdown is started, and the drain valve 46 is opened from the closed state as shown in FIG. Along with this, as shown in FIG. 6A, the engine rotation speed NE starts to decrease. At this stage, there is no change in the intake pressure PM and the intake pressure PMtac, PMtao upstream of the throttle valve, the pressure in the intercooler 13 on the inlet side of the drainage passage 45, and the exhaust passage where the outlet 45a of the drainage passage 45 is located. The pressure difference between around 5 (atmospheric pressure) is maintained. For this reason, the condensed water accumulated in the water collecting portion 13a of the intercooler 13 is discharged to the exhaust passage 5 through the drain passage 45, the drain valve 46, the check valve 47, and the EGR passage 17 due to the pressure difference. .

  Thereafter, when the post-deceleration time Tdown exceeds the reference time A as shown in FIG. 6C at time t2, the ABV 42 is opened from the closed state as shown in FIG. 6E. Along with this, as shown in FIG. 6B, the intake pressure PM and the throttle valve upstream side intake pressure PMtao start to decrease. Thereby, surging of the supercharger 7 can be prevented.

  Thereafter, when the post-deceleration time Tdown exceeds the drain valve opening time Tdrv at time t3 as shown in FIG. 6C, the drain valve 46 is closed. Thereafter, when the post-deceleration time Tdown exceeds the ABV valve opening time Tabv at time t4 as shown in FIG. 6 (d), the ABV 42 is closed as shown in FIG. 6 (e). In this way, since the ABV 42 is opened after the drain valve 46 is opened for a while, the throttle valve upstream intake pressure PMtao does not decrease to the atmospheric pressure when the drain valve 46 is opened. The condensed water accumulated in the water collecting part 13a can be discharged at once through the drainage passage 45 and the like. Thereafter, by opening the ABV 42, it is possible to reduce the supercharging pressure on the downstream side of the compressor 8 and prevent surging of the supercharger 7 from occurring.

  According to the control device for an engine with a supercharger in this embodiment described above, in the intercooler 13, moisture contained in the intake air and EGR gas flowing therethrough may be condensed by cooling, and the condensed water is It is once collected in the water collection part 13a. Then, when the pressure around the water collection portion 13a is higher than the pressure around the exhaust passage 5, that is, when there is a pressure difference, the drain valve 46 is opened, so that the water collection portion 13a accumulates. The condensed water is discharged to the exhaust passage 5 through the drain passage 45 and the like.

  Here, for example, when the engine 1 is decelerating, the throttle valve 21 of the electronic throttle device 14 is closed so that the intake pressure in the intake passage 3 upstream of the throttle valve 21 (the intake pressure PMtac upstream of the throttle valve) is increased. As a result, the pressure around the water collecting portion 13a becomes higher than the pressure around the exhaust passage 5. On the other hand, if the intake pressure in the intake passage 3 upstream from the throttle valve 21, that is, the intake passage 3 downstream from the compressor 8, suddenly increases, surcharge may occur in the turbocharger 7. is there. In this surging, when the intake pressure (the intake pressure PMtac upstream of the throttle valve) suddenly increases, the intake pressure is opened to the intake passage 3 upstream of the compressor 8 via the air bypass passage 41 by opening the ABV 42. It is suppressed by letting it escape. However, opening the ABV 42 and releasing the intake pressure during deceleration operation of the engine 1 is effective for surging the supercharger 7, but between the surroundings of the water collection portion 13 a and the exhaust passage 5. It is disadvantageous in the sense of securing the pressure difference.

  According to the configuration of this embodiment, when the engine 1 is decelerated, the ECU 50 opens the drain valve 46 from the closed state, and after a while, the ABV 42 is opened from the closed state. Accordingly, since the drain valve 46 is opened before the ABV 42 is opened and the pressure around the water collecting portion 13a is reduced, the pressure between the water collecting portion 13a and the exhaust passage 5 is increased. The drain valve 46 is opened with the difference kept sufficiently. For this reason, it is possible to effectively take measures against surging of the supercharger 7 by using the ABV 42, and the condensation accumulated in the water collecting portion 13a in the intercooler 13 using the intake air pressure during the deceleration operation of the engine 1. Water can be effectively discharged at once into the exhaust passage 5 as a discharge destination. Further, since the condensed water can be discharged at once to the discharge destination, the stagnation of the condensed water in the drainage passage 45 can be prevented.

Second Embodiment
Next, a second embodiment in which the control device for an engine with a supercharger according to the present invention is embodied will be described in detail with reference to the drawings.

  In the following embodiments, the same components as those in the first embodiment are denoted by the same reference numerals, description thereof is omitted, and different points are mainly described.

  This embodiment differs from the first embodiment in terms of the processing content of the condensed water discharge control. In FIG. 7, an example of the processing content of the condensed water discharge control of this embodiment is shown with a flowchart.

  The configuration of the flowchart of FIG. 7 is different in that the processing of step 120 is added between step 103 and step 104 in the flowchart of FIG.

  That is, in step 120 after shifting from step 103, the ECU 50 determines whether or not the condensed water thawing flag XDFT is “1”. As will be described later, the flag XDFT is “1” when the condensed water is thawed and discharge of the condensed water is allowed, and “0” when the condensed water is not thawed and discharge of the condensed water is prohibited. Is set to. When this determination result is affirmative, the ECU 50 shifts the process to step 104, and executes the processes after step 104. On the other hand, when this determination result is negative, the ECU 50 jumps the process to step 109 without opening the drain valve 46.

  FIG. 8 is a flowchart showing an example of a thawing determination process for determining the thawing of condensed water, that is, for setting the condensed water thawing flag XDFT described above. When the process shifts to this routine, in step 200, the ECU 50 waits for the engine 1 to start and shifts the process to step 201. The ECU 50 can make this determination based on the engine speed NE or the like.

  In step 201, the ECU 50 takes in the coolant temperature THWs at the start and the outside air temperature THAs at the start. Here, the ECU 50 takes in the cooling water temperature THWs at the start from the detection value of the water temperature sensor 53 and takes in the outside air temperature THAs at the start from the detection value of the outside air temperature sensor 56.

  In step 202, the ECU 50 determines whether or not the coolant temperature THWs at the start is lower than “5 ° C.”. If this determination result is affirmative, the ECU 50 proceeds directly to step 204, and if this determination result is negative, the ECU 50 proceeds to step 203.

  In step 203, the ECU 50 determines whether or not the outside air temperature THAs at the start is lower than “5 ° C.”. If this determination result is affirmative, the ECU 50 proceeds to step 204, and if this determination result is negative, the ECU 50 jumps the process to step 213.

  In step 204 after shifting from step 202 or step 203, the ECU 50 obtains a first integrated intake air amount TGathw corresponding to the coolant temperature THWs at the time of starting. The ECU 50 can obtain the first integrated intake air amount TGathw with reference to a map as shown in FIG. 9, for example. In this map, as the cooling water temperature THWs at the time of starting or the outside air temperature THAs at the time of starting becomes lower than “5 ° C.”, the first integrated intake air amount TGathw or the second integrated intake air amount TGatha increases and becomes “5 ° C.”. When the above is reached, the first integrated intake air amount TGathw or the second integrated intake air amount TGatha is set to “0”.

  Here, the first cumulative intake air amount TGathw and the second cumulative intake air amount TGatha are the values after the warm-up necessary for thawing the condensed water in the intercooler 13 when the engine 1 is started. It means the integrated value of the intake air amount Ga.

  Next, in step 205, the ECU 50 obtains a second integrated intake air amount TGatha corresponding to the outside air temperature THAs at the start. The ECU 50 can obtain the second integrated intake air amount TGatha with reference to a map as shown in FIG. 9, for example.

  Next, in step 206, the ECU 50 determines whether or not the first integrated intake air amount TGathaw is greater than the second integrated intake air amount TGatha. If this determination result is affirmative, the ECU 50 proceeds to step 207, and if this determination result is negative, the ECU 50 proceeds to step 208.

  In step 207, the ECU 50 sets the first integrated intake air amount TGathw as the determined integrated intake air amount TGa. In step 208, the ECU 50 sets the second integrated intake air amount TGatha as the determined integrated intake air amount TGa.

  Thereafter, the process proceeds from step 207 or step 208, and in step 209, the ECU 50 takes in the current coolant temperature THW.

  Next, in step 210, the ECU 50 determines whether or not the coolant temperature THW is higher than “60 ° C.”. This value of “60 ° C.” is an example for determining warm-up of the engine 1. If this determination result is affirmative, the ECU 50 proceeds to step 211, and if this determination result is negative, the ECU 50 proceeds to step 214.

  In step 211, the ECU 50 obtains a third integrated intake air amount TGa60 after the coolant temperature THW reaches “60 ° C.”. The ECU 50 can obtain the third integrated intake air amount TGa60 by integrating the intake air amount Ga measured at any time. The third integrated intake air amount Tga60 means an integrated value of the intake air amount Ga that has passed through the intercooler 13 after the warm-up of the engine 1 is completed.

  Next, in step 212, the ECU 50 determines whether or not the determined integrated intake air amount TGa is smaller than the third integrated intake air amount TGa60. This determination means determining whether or not the condensed water frozen in the intercooler 13 has been thawed (whether or not it has been frozen). If this determination result is affirmative, the ECU 50 proceeds to step 213, and if this determination result is negative, the ECU 50 proceeds to step 214.

  Then, in step 213 after shifting from step 203 or step 212, the ECU 50 assumes that the condensed water can be thawed and has not been frozen, and in order to allow the condensed water to be discharged from the water collecting section 13a, the condensed water thawed. After setting the flag XDFT to “1”, the process returns to step 200.

  On the other hand, in step 214 after shifting from step 210 or step 212, the ECU 50 determines that the condensed water cannot be thawed and is frozen, and in order to inhibit the condensed water from being discharged from the water collecting portion 13a, After setting the flag XDFT to “0”, the process returns to step 200.

  According to the above control, the ECU 50 determines whether or not the condensed water in the intercooler 13 is frozen based on the detected coolant temperature THWs at the start and the outside air temperature THAs at the start. When the ECU 50 determines that the condensed water is not frozen (thawed), the ECU 50 allows the drain valve 46 to open, that is, sets the condensed water thawing flag XDFT to “1”. Further, when the ECU 50 determines that the condensed water is frozen (not defrosted), the ECU 50 prohibits the opening of the drain valve 46, that is, sets the condensed water thawing flag XDFT to “0”. ing.

  According to the control device for an engine with a supercharger of this embodiment described above, in addition to the effects of the first embodiment, the following effects are obtained. That is, the ECU 50 determines whether or not the condensed water in the intercooler 13 is frozen based on the cooling water temperature THWs and the outside air temperature THAs when the engine 1 is started. When it is determined that the condensed water is not frozen, the drain valve 46 is allowed to open, and when it is determined that the condensed water is frozen, the drain valve 46 is prohibited from opening. . Therefore, when the condensed water is frozen, the drain valve 46 is not allowed to open, and the drain valve 46 is not opened unnecessarily. For this reason, it is possible to determine whether or not the condensed water is frozen without using a dedicated temperature sensor. Moreover, the operating frequency of the drain valve 46 can be reduced, and the durability of the drain valve 46 can be improved.

<Third Embodiment>
Next, a third embodiment that embodies the control device for an engine with a supercharger according to the present invention will be described in detail with reference to the drawings.

  In this embodiment, the configuration is different from that of each of the above embodiments in terms of processing content of the condensed water discharge control. In this embodiment, the process of the flowchart shown in FIG. 10 is performed instead of the process of the flowchart shown in FIG. FIG. 10 is a flowchart showing an example of the processing content of the condensed water discharge control. The flowchart of FIG. 10 is different in that the process of step 125 is performed instead of the process of step 120 in the flowchart of FIG.

  That is, in step 125 after shifting from step 103, the ECU 50 determines whether or not the condensed water full flag XFUL is “1”. As will be described later, this flag XFUL is set to “1” when the water collecting portion 13a is full of condensed water and discharge of condensed water is allowed, and the water collecting portion 13a is not full of condensed water but discharges condensed water. Is set to “0”. When this determination result is affirmative, the ECU 50 shifts the process to step 104, and executes the processes after step 104. On the other hand, when this determination result is negative, the ECU 50 jumps the process to step 109 without opening the drain valve 46.

  Moreover, in this embodiment, the process for determining whether the water collection part 13a is full with condensed water is performed. FIG. 11 is a flowchart showing an example of the fullness determination process. When the process proceeds to this routine, in step 300, the ECU 50 takes in the engine rotational speed NE and the engine load KL. Here, the ECU 50 can determine the engine load KL from the relationship between the engine rotational speed NE and the intake air amount Ga or the intake pressure PM.

  Next, in step 301, the ECU 50 takes in the intercooler outlet temperature THIO based on the detection value of the intercooler outlet temperature sensor 57.

  Next, in step 302, the ECU 50 obtains the condensed water count value cwat based on the engine speed NE, the engine load KL, and the intercooler outlet temperature THIO. Here, the ECU 50 can obtain the condensed water count value cwat by referring to, for example, the maps shown in FIGS.

  In the map shown in FIG. 12, the relationship of the condensed water count value cwat with respect to the engine speed NE and the engine load KL when the intercooler outlet temperature THIO is “20 ° C.” is set. In this map, the condensed water count value cwat is set as an integer of “0 to 10”, for example.

  In the map shown in FIG. 13, the relationship of the condensed water count value cwat to the engine rotational speed NE and the engine load KL when the intercooler outlet temperature THIO is “30 ° C.” is set. In this map, the condensed water count value cwat is set as an integer of “0-6”, for example.

  In the map shown in FIG. 14, the relationship of the condensed water count value cwat with respect to the engine rotational speed NE and the engine load KL when the intercooler outlet temperature THIO is “40 ° C.” is set. In this map, the condensed water count value cwat is set as an integer of “0 to 2”, for example.

  In the map shown in FIG. 15, the relationship between the condensed water count value cwat and the engine rotational speed NE and the engine load KL when the intercooler outlet temperature THIO is “50 ° C.” is set. In this map, for example, the condensed water count value cwat is set to “0” in the entire area.

  In the map shown in FIG. 16, the relationship between the engine rotation speed NE and the engine load KL when the intercooler outlet temperature THIO is “65 ° C.” is set. In this map, the condensed water count value cwat is set as an integer of “−2 to 0”, for example.

  In the map shown in FIG. 17, the relationship of the condensed water count value cwat with respect to the engine speed NE and the engine load KL when the intercooler outlet temperature THIO is “80 ° C.” is set. In this map, the condensed water count value cwat is set as an integer of “−6 to −1”, for example.

  Here, when the intercooler outlet temperature THIO is in the range of “20 ° C. to 50 ° C.”, the condensed water count value cwat becomes a positive value of 0 or more because the water vapor is cooled and condensed water is generated, and the water collecting section 13a. Means more condensed water. On the other hand, when the intercooler outlet temperature THIO is in the range of “65 ° C., 80 ° C.”, the condensed water count value cwat becomes a negative value of 0 or less means that the condensed water in the water collecting portion 13a evaporates and decreases. To do.

  Next, at step 303, the ECU 50 determines whether or not the drain valve opening flag XDRV is “1”, that is, whether or not the drain valve 46 is open. If this determination result is affirmative, the ECU 50 proceeds to step 304, and if this determination result is negative, the ECU 50 proceeds to step 305.

  In step 304, the ECU 50 determines whether or not the condensed water thawing flag XDFT is “0”. This flag XDFT is set by the processing of the flowchart of FIG. If this determination result is affirmative, the ECU 50 proceeds to step 307, and if this determination result is negative, the ECU 50 proceeds to step 306.

  In step 307, the ECU 50 updates the determination count value CWAT (i) every time the drain valve 46 opens. That is, the ECU 50 obtains a new determination count value CWAT (i) by adding the condensed water count value cwat to the previous determination count value CWAT (i-1) and further subtracting the predetermined value B (integer).

  Thereafter, the ECU 50 sets the condensed water thawing flag XDFT to “1” on the assumption that the condensed water has been thawed at step 308, and then proceeds to step 309.

  On the other hand, in step 305, the ECU 50 sets the condensed water thawing flag XDFT to “0”, assuming that the condensed water has not been thawed.

  In step 306 after shifting from step 304 or step 305, the ECU 50 updates the determination count value CWAT (i) at regular intervals. That is, a new determination count value CWAT (i) is obtained by adding the condensed water count value cwat to the previous determination count value CWAT (i-1). Thereafter, the ECU 50 proceeds to step 309.

  Then, in step 309 after shifting from step 306 or step 308, the ECU 50 determines whether or not the determination count value CWAT (i) is larger than a predetermined value α. Here, the predetermined value α corresponds to a value when the condensed water in the water collecting portion 13a is full. When this determination result is affirmative, the ECU 50 proceeds to step 310, and when this determination result is negative, the ECU 50 proceeds to step 311.

  In step 310, the ECU 50 sets the condensed water full flag XFUL to “1”, assuming that the condensed water in the water collecting unit 13 a is full, and returns the process to step 300.

  On the other hand, in step 311, the ECU 50 determines whether or not the determination count value CWAT (i) is smaller than “0”. If this determination result is negative, the ECU 50 proceeds to step 313 as it is. If this determination result is affirmative, the ECU 50 sets the determination count value CWAT (i) to “0” in step 312, and then proceeds to step 313.

  Then, in step 313 after shifting from step 311 or step 312, the ECU 50 sets the condensed water full flag XFUL to “0” on the assumption that the condensed water in the water collecting section 13a is not full, and returns the process to step 300.

  According to the above control, the ECU 50 estimates the amount of condensed water in the water collecting portion 13a based on the detected engine rotational speed NE, engine load KL, and intercooler outlet temperature THIO. Then, when the estimation result reaches a predetermined specified amount, the ECU 50 allows the drain valve 46 to open, that is, sets the condensed water full flag XFUL to “1”. Further, the ECU 50 prohibits the opening of the drain valve 46, that is, sets the condensed water full flag XFUL to “0” when the estimation result does not become a predetermined prescribed amount.

  Here, in this embodiment, the condensed water accumulated in the water collecting portion 13a is discharged by opening the drain valve 46 during the deceleration operation of the engine 1. However, when the steady operation of the engine 1 continues for a long time and the deceleration operation is not performed easily, the generation of condensed water continues in the intercooler 13, and the water collecting portion 13a becomes full of condensed water and condenses from the water collecting portion 13a. There is a possibility that water overflows and is sucked into the combustion chamber 16. Therefore, in this embodiment, a situation in which the engine 1 is not easily decelerated is dealt with, and the forced EGR cut control is executed in connection with the condensed water discharge control. FIG. 18 is a flowchart showing an example of the processing content of forced EGR cut determination. FIG. 19 is a flowchart showing an example of the processing content of forced EGR cut control.

  When the process proceeds to the routine shown in FIG. 18, in step 400, the ECU 50 captures the above-described determination count value CWAT (i).

  Next, at step 410, the ECU 50 determines whether or not the determination count value CWAT (i) is greater than a predetermined value γ. Here, the predetermined value γ can be set to a value immediately before the condensed water in the water collecting unit 13a is full, for example. When this determination result is affirmative, the ECU 50 proceeds to step 420, and when this determination result is negative, the ECU 50 proceeds to step 440.

  In step 420, the ECU 50 sets the forced EGR cut flag XEGRCUT to “1” to allow the forced EGR cut, and the process returns to step 400.

  On the other hand, in step 430, the ECU 50 sets the forced EGR cut flag XEGRCUT to “0” in order to prohibit the forced EGR cut, and the process returns to step 400.

  On the other hand, when the process proceeds to the routine shown in FIG. 19, in step 500, the ECU 50 takes in the coolant temperature THW, the outside air temperature THA, the engine rotational speed NE, and the engine load KL, respectively.

  Next, at step 510, the ECU 50 obtains the target opening degree Tegr of the EGR valve 18 according to the coolant temperature THW, the outside air temperature THA, the engine speed NE, and the engine load KL. The ECU 50 can obtain the target opening degree Tegr by referring to a predetermined map, for example.

  Next, in step 520, the ECU 50 determines whether or not the forced EGR cut flag XEGRCUT is “0”, that is, whether or not forced EGR cut is prohibited. When this determination result is affirmative, the ECU 50 proceeds to step 530, and when this determination result is negative, the ECU 50 proceeds to step 540.

  In step 530, since the forced EGR cut is prohibited, the ECU 50 controls the EGR valve 18 to the target opening degree Tegr and returns the process to step 500.

  On the other hand, in step 540, since the forced EGR cut is permitted, the ECU 50 controls the EGR valve 18 to be fully closed and returns the process to step 500.

  According to the above control, the ECU 50 determines that the condensed water determination count value CWAT (i) is larger than the predetermined value γ in order to cope with a state in which the steady operation or the like continues for a long time in the engine 1 and the deceleration operation is not easily performed. In such a case, the EGR valve 18 is forcibly fully closed to cut the EGR, and the generation of condensed water in the intercooler 13 is suppressed.

  Here, FIG. 20 shows an example of behavior of various parameters related to various controls of this embodiment in a time chart. In FIG. 20, when the intercooler outlet temperature THIO is relatively low at times t1 to t7, for example, “20 ° C. to 50 ° C.” is assumed, and at times t11 to t17, the intercooler outlet temperature THIO is In the case of a relatively high temperature, for example, a case of “65 ° C., 80 ° C.” is assumed.

  First, when the intercooler outlet temperature THIO is relatively low, before the time t2, as shown in FIG. 20 (a), the throttle opening TA becomes constant at a predetermined opening, and the engine 1 is in steady operation. As shown in FIG. 5B, the intake pressure PM and the throttle valve upstream intake pressure PMtac, PMtao are constant above atmospheric pressure. Since the intercooler outlet temperature THIO is relatively low, the determination count value CWAT (i) tends to increase as shown in FIG.

  When the determination count value CWAT (i) exceeds the predetermined value α as shown in FIG. 20 (f) at time t1, the condensed water full flag XFUL is “1” as shown in FIG. 20 (g). Thus, the drain valve 46 is allowed to open.

  Thereafter, at time t2, as shown in FIG. 20 (a), the throttle opening TA falls toward the idle opening, and at time t3, the throttle opening TA becomes a deceleration determination opening, and the engine 1 is decelerated. When the determination is made, the drain valve 46 opens from the closed state as shown in FIG. At this time, as shown in FIG. 20 (f), the determination count value CWAT (i) is subtracted by the predetermined value B and falls below the predetermined value α. As shown in FIG. 20 (g), the condensed water full flag XFUL is set. Returning from “1” to “0”, the subsequent opening of the drain valve 46 is prohibited, and the post-deceleration time Tdown is counted as shown in FIG. Along with this, as shown in FIG. 20A, the engine rotation speed NE starts to decrease. At this stage, there is no change in the intake pressure PM and the throttle valve upstream intake pressure PMtac, PMtao, the pressure around the water collection portion 13a on the inlet side of the drainage passage 45, and the exhaust where the outlet 45a of the drainage passage 45 is located. A pressure difference is maintained between the pressure around the passage 5 (atmospheric pressure). For this reason, the condensed water accumulated in the water collecting portion 13 a is discharged to the exhaust passage 5 through the drainage passage 45, the drainage valve 46, the check valve 47 and the EGR passage 17 due to the pressure difference.

  Thereafter, at time t4, when the post-deceleration time Tdown exceeds the reference time A as shown in FIG. 20C, the ABV 42 is opened from the closed state as shown in FIG. Accordingly, as shown in FIG. 20B, the intake pressure PM and the throttle valve upstream side intake pressure PMtao start to decrease. Thereby, surging of the supercharger 7 can be prevented.

  Thereafter, when the post-deceleration time Tdown exceeds the drain valve opening time Tdrv at time t5 as shown in FIG. 20 (c), the drain valve 46 is closed as shown in FIG. 20 (d). Thereafter, when the post-deceleration time Tdown exceeds the ABV valve opening time Tabv at time t6 as shown in FIG. 20 (c), the ABV 42 is closed as shown in FIG. 20 (e).

  Thereafter, at time t7, as shown in FIG. 20 (f), when the determination count value CWAT (i) exceeds a predetermined value α, the condensed water full flag XFUL is set to “1”.

Next, when the intercooler outlet temperature THIO is relatively high, before time t12, as shown in FIG. 20 (a), the throttle opening TA becomes constant at a predetermined opening, and the engine 1 is in steady operation. As shown in FIG. 4B, the intake pressure PM and the throttle valve upstream intake pressure PMtac, PMtao are constant above atmospheric pressure. Since the intercooler outlet temperature THIO is relatively high, the determination count value CWAT (i) tends to decrease as shown in FIG. Further, as shown in FIG. 20G, the condensed water full flag XFUL is “1”.
When the determination count value CWAT (i) falls below the predetermined value γ at time t11 as shown in FIG. 20 (f), the forced EGR cut flag XEGRCUT is “1” as shown in FIG. 20 (h). To “0”. Thereby, EGR cut is prohibited and forced full closing of the EGR valve 18 is prohibited.

  Thereafter, at time t12, as shown in FIG. 20A, the throttle opening TA falls toward the idle opening, and at time t13, the throttle opening TA becomes the deceleration determination opening, and the engine 1 is decelerated. When the determination is made, the drain valve 46 opens from the closed state as shown in FIG. 4D, and the post-deceleration time Tdown starts counting as shown in FIG. At this time, the determination count value CWAT (i) is subtracted by a predetermined value B as shown in FIG. Along with this, as shown in FIG. 20A, the engine rotation speed NE starts to decrease. At this stage, the intake pressure PM and the throttle valve upstream intake pressure PMtao begin to decrease, but are higher than the atmospheric pressure, so the pressure around the water collection portion 13a on the inlet side of the drainage passage 45 and the drainage passage 45 A pressure difference is maintained with respect to the pressure around the exhaust passage 5 (atmospheric pressure) in which the outlet 45a is located. For this reason, the condensed water accumulated in the water collecting portion 13 a is discharged to the exhaust passage 5 through the drainage passage 45, the drainage valve 46, the check valve 47 and the EGR passage 17 due to the pressure difference.

  Thereafter, at time t14, when the post-deceleration time Tdown exceeds the reference time A as shown in FIG. 20C, the ABV 42 is opened from the closed state as shown in FIG. Accordingly, as shown in FIG. 20B, the intake pressure PM and the throttle valve upstream side intake pressure PMtao continue to decrease. Thereby, surging of the supercharger 7 can be prevented.

  Thereafter, when the post-deceleration time Tdown exceeds the drain valve opening time Tdrv at time t15 as shown in FIG. 20C, the drain valve 46 is closed as shown in FIG. Thereafter, when the post-deceleration time Tdown exceeds the ABV valve opening time Tabv at time t16 as shown in FIG. 20 (c), the ABV 42 is closed as shown in FIG. 20 (e). Thereafter, when the determination count value CWAT (i) falls below the predetermined value α at time t7 as shown in FIG. 20 (f), the condensed water full flag XFUL is “1” as shown in FIG. 20 (g). Return to "0".

  According to the control device for a turbocharged engine of this embodiment described above, in addition to the functions and effects of the second embodiment, the following functions and effects are obtained. That is, the ECU 50 calculates the condensed water determination count value CWAT (i) based on the operating state of the engine 1, thereby estimating the amount of condensed water in the water collecting portion 13 a. When the estimation result reaches a predetermined specified amount, the ECU 50 allows the drain valve 46 to be opened. Therefore, when the condensed water in the water collecting portion 13a is not a specified amount, that is, when the condensed water is not accumulated in the water collecting portion 13a, the drain valve 46 is not allowed to open, and the drain valve 46 The valve is not opened in vain. For this reason, it is possible to determine whether or not the water collecting portion 13a is full of condensed water without using a dedicated sensor such as a water level sensor. Moreover, the operating frequency of the drain valve 46 can be reduced, and the durability of the drain valve 46 can be improved.

  In this embodiment, the ECU 50 determines the condensed water determination count value CWAT (i) based on the operating state of the engine 1, thereby estimating the amount of condensed water in the water collecting section 13 a. Then, when the estimation result is equal to or greater than a predetermined specified amount, the EGR valve 18 is forcibly fully closed by the ECU 50. Therefore, when the condensed water in the water collecting portion 13a reaches a specified amount, the EGR valve 18 is forcibly fully closed by the ECU 50, and the inflow of EGR gas to the intake passage 3 is shut off. The generation of condensed water is suppressed in the interior. For this reason, it can prevent that the water collection part 13a becomes full with condensed water, and it can prevent that condensed water overflows from the water collection part 13a, and prevents the condensed water from being sucked into the combustion chamber 16 carelessly. be able to.

  Note that the present invention is not limited to the above-described embodiments, and a part of the configuration can be changed as appropriate without departing from the spirit of the invention.

  (1) In each of the above embodiments, the drain valve 46 is opened from the closed state during the deceleration operation of the engine 1, and after a while, the ABV 42 is opened from the closed state. On the other hand, at the time of the deceleration operation of the engine 1, the drain valve 46 can be opened from the closed state, and the ABV 42 can be opened from the closed state simultaneously with the opening of the drain valve 46. In this case as well, the same effects as those of the above embodiments can be obtained.

  (2) In each of the above embodiments, the outlet 45a of the drainage passage 45 is connected to the EGR passage 17 in the vicinity of the exhaust passage 5 and upstream of the EGR valve 18 as a discharge destination. On the other hand, the outlet of the drainage passage can be directly connected to the exhaust passage as a discharge destination or connected to the crankcase of the engine. The discharge destination is not limited to the above portion as long as it can be at a lower pressure than the intercooler.

  The present invention can be used for an automobile engine regardless of, for example, a gasoline engine or a diesel engine.

1 Engine 3 Intake Passage 5 Exhaust Passage 7 Supercharger 8 Compressor 9 Turbine 10 Rotating Shaft 13 Intercooler 13a Water Collection Unit 14 Electronic Throttle Device (Intake Amount Control Valve)
16 Combustion chamber 17 EGR passage (exhaust gas recirculation passage)
17a outlet 17b inlet 18 EGR valve (exhaust gas recirculation valve)
21 Throttle valve 23 Throttle sensor (operating state detection means)
27 Accelerator sensor (operating state detection means)
41 Air bypass passage 42 ABV (Air bypass valve)
45 Drain passage 45a Outlet 46 Drain valve 50 ECU (control means)
51 Intake pressure sensor (operating state detection means)
52 Rotational speed sensor
53 Water temperature sensor (operating state detection means, cooling water temperature detection means)
54 Air flow meter (Operating state detection means)
55 Air-fuel ratio sensor (operating state detection means)
56 Outside air temperature sensor (operating state detecting means, outside air temperature detecting means)
57 Intercooler outlet temperature sensor (operating state detection means)

Claims (4)

A turbocharger provided between an intake passage and an exhaust passage of the engine for boosting intake air in the intake passage;
The supercharger includes a compressor disposed in the intake passage, a turbine disposed in the exhaust passage, and a rotation shaft that connects the compressor and the turbine so as to be integrally rotatable.
A part of the exhaust discharged from the combustion chamber of the engine to the exhaust passage is made to flow as an exhaust recirculation gas to the intake passage and is recirculated to the combustion chamber, and the exhaust recirculation gas in the exhaust recirculation passage is adjusted. An exhaust gas recirculation device including an exhaust gas recirculation valve for,
The exhaust gas recirculation passage has an inlet connected to the exhaust passage downstream of the turbine and an outlet connected to the intake passage upstream of the compressor;
An intake air amount adjustment valve for adjusting the intake air amount in the intake passage;
An intercooler for cooling the intake air that is provided downstream of the compressor and upstream of the intake air amount adjustment valve, and boosted by the supercharger;
A water collecting section provided in the intercooler, for collecting condensed water in the intercooler;
A drainage passage for discharging condensed water collected in the water collection section to a discharge destination having a lower pressure than the water collection section;
A drain valve for opening and closing the drain passage;
An air bypass passage that bypasses between the intake passage downstream of the compressor and the intake passage upstream of the compressor;
An air bypass valve for opening and closing the air bypass passage;
An operating state detecting means for detecting the operating state of the engine;
Control means for controlling at least the exhaust gas recirculation valve, the drain valve and the air bypass valve based on the detected operating state;
In the control device for an engine with a supercharger, the intake air amount adjustment valve is opened during acceleration operation or steady operation of the engine, and is closed when the engine is stopped or decelerated.
The control means opens the drain valve from a closed state during deceleration operation of the engine, and opens the air bypass valve from the closed state simultaneously with or after the drain valve is opened. A control device for a supercharged engine. The operating state detecting means includes a cooling water temperature detecting means for detecting the temperature of the cooling water of the engine, and an outside air temperature detecting means for detecting the temperature of the outside air,
The control means determines whether or not the condensed water in the intercooler is frozen based on the detected temperature of the cooling water and the temperature of the outside air, and the condensed water is not frozen. 2. The supercharger-equipped engine control device according to claim 1, wherein the drainage valve is allowed to open when it is determined as follows.   The control means estimates the amount of condensed water in the water collecting section based on the detection result of the operating state detection means, and allows the drain valve to open when the estimation result reaches a predetermined specified amount. The supercharger-equipped engine control device according to claim 1 or 2.   The control means estimates the amount of condensed water in the water collecting section based on the detection result of the operating state detection means, and forcibly turns on the exhaust gas recirculation valve when the estimation result reaches a predetermined specified amount. The control device for an engine with a supercharger according to any one of claims 1 to 3, wherein the control device is closed.

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