JP2010112287A - Abnormality detection device for pcv system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately detect abnormality of a PCV system in an internal combustion engine. <P>SOLUTION: The abnormality detection device for the PCV system includes a turbocharger (218) for supercharging using exhaust gas in the internal combustion engine, an EGR passage (240) for circulating a portion of the exhaust gas as EGR gas in an intake system, an EGR valve (242) provided in the EGR passage (240) for controlling the flow rate of the EGR gas, an airflow meter (219) for measuring the flow rate of air taken into the intake system, an EGR control means (110) for controlling the EGR valve (242) to reduce the flow rate of the EGR gas when the flow rate of air measured by the airflow meter (219) is less than a prescribed flow rate, a supercharging pressure specifying means (230) for specifying supercharging pressure of the turbocharger (218), and a detection means (120) for detecting abnormality of the PCV system (271) based on the supercharging pressure specified by the supercharging pressure specifying means (230) during EGR control. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technical field of a PCV system abnormality detection device for detecting a PCV (Positive Crankcase Ventilation) system abnormality provided in an internal combustion engine such as an engine.

  As this type of PCV abnormality detection device, for example, those disclosed in Patent Documents 1 to 3 are known. For example, in Patent Document 1, the amount of air flowing through the intake system (that is, the amount of intake air) detected by an air amount sensor provided upstream of the connection portion with the blow-by gas passage of the intake system is defined as a predetermined determination value. By comparing, for example, an abnormality of the PCV system such as a blow-by gas passage being damaged or coming off from the intake pipe is detected. For example, in Patent Document 2, an abnormality in the blowby gas passage is detected by detecting the pressure in the blowby gas passage by a pressure sensor. For example, in Patent Document 3, an abnormality in the PCV system is detected based on the pressure difference between the oil mist separator pressure in the blow-by gas passage and the intake pipe pressure.

  Further, for example, in Patent Document 4, an oil component contained in blow-by gas returned to the intake system of the internal combustion engine by the PCV system is disposed in a turbocharger or an EGR (Exhaust Gas Recirculation) passage disposed in the intake system. Techniques for suppressing inflow have been proposed.

JP 2007-002838 A Japanese Patent Laid-Open No. 10-184336 Japanese Utility Model Publication No. 03-051121 JP 2007-162530 A

  However, in an internal combustion engine employing EGR, the amount of intake air varies depending not only on the opening degree of the throttle valve provided in the intake passage but also on the flow rate of EGR gas. Therefore, the technique disclosed in Patent Document 1 described above. However, there is a technical problem that it becomes difficult to accurately detect abnormality of the PCV system.

  The present invention has been made in view of the above-described problems, for example, and an object of the present invention is to provide a PCV system abnormality detection device capable of accurately detecting a PCV system abnormality provided in an internal combustion engine.

  In order to solve the above problems, a PCV system abnormality detection apparatus of the present invention is a PCV system abnormality detection apparatus that detects a PCV system abnormality that recirculates blow-by gas in a crankcase of an internal combustion engine to an intake system of the internal combustion engine. A turbocharger that performs supercharging using the exhaust gas of the internal combustion engine, an EGR passage that recirculates a part of the exhaust gas as EGR gas to the intake system, and the EGR passage. An EGR valve that can adjust the flow rate of the air, an air flow meter that measures the flow rate of air sucked into the intake system, and the ERG gas when the flow rate of air measured by the air flow meter is less than a predetermined flow rate EGR control means for performing EGR control for controlling the EGR valve so that the flow rate of the turbocharger is reduced, and a supercharging pressure of the turbocharger. Comprising a boost pressure identifying means for a constant, and detecting means for detecting an abnormality of the PCV system based on the boost pressure specified by the supercharging pressure identifying means when said EGR control.

  According to the PCV system abnormality detection device of the present invention, for example, a blow-by gas that is provided in an internal combustion engine such as a diesel engine or a gasoline engine and connects, for example, the crankcase of the internal combustion engine and the upstream side of the turbocharger compressor in the intake system. PCV system abnormalities including passages (or PCV piping) (ie, abnormalities such as PCV system breakage or PCV system blow-by gas passages being disconnected from the intake system) are accurately detected by detection means. Can be detected.

  Specifically, according to the present invention, when a PCV system abnormality occurs, the EGR gas flow rate is reduced by EGR control by the EGR control means, and as a result, the turbocharger supercharging pressure is increased. Thus, the PCV system abnormality can be accurately detected by the detecting means.

  Here, when an abnormality of the PCV system occurs, outside air flows in from the portion where the abnormality of the PCV system occurs, and the flow rate of the air flowing through the intake system is reduced accordingly. Along with this, the air flow rate measured by the air flow meter also decreases. The air flow meter is provided, for example, on the upstream side of a connection portion between the PCV system and the intake system (typically, a connection portion where the blow-by gas passage and the intake pipe are connected to each other).

  When the air flow rate measured by the air flow meter is less than the predetermined flow rate, the EGR control means has an excessive amount of EGR gas (that is, the EGR gas that is currently recirculated to the intake system is normal) EGR control is performed to control the EGR valve so as to reduce the flow rate of the ERG gas. That is, when the air flow rate measured by the air flow meter is less than the predetermined flow rate, the EGR control means controls the EGR valve to the closed side in order to reduce the ERG gas flow rate (ie, open the EGR valve). Reduce the degree). When the flow rate of EGR gas is reduced by such EGR control, the flow rate of the exhaust gas flowing into the turbocharger is increased accordingly. For example, the supercharging pressure of supercharging by the turbocharger is controlled by open loop control. In some cases, the supercharging pressure increases. That is, when a PCV system abnormality occurs, the flow rate of EGR gas is reduced by EGR control, and as a result, the supercharging pressure of supercharging by the turbocharger increases. In other words, due to an abnormality in the PCV system, the turbocharger supercharging pressure increases due to EGR control. Therefore, when the EGR control is performed, based on the turbocharge pressure specified by the turbocharge pressure specifying means (for example, the turbocharge pressure specified by the boost pressure specifying means and the normal time By comparing the turbocharger supercharging pressure with a preset reference supercharging pressure), the PCV system abnormality can be accurately detected by the detecting means.

  The “specification” of the supercharging pressure according to the present invention may be, for example, directly or indirectly detecting, measuring, estimating, calculating, etc. the supercharging pressure, as long as the supercharging pressure can be specified or acquired in some form. It is a good purpose.

  As described above, according to the PCV system abnormality detection device of the present invention, a PCV system abnormality provided in the internal combustion engine can be accurately detected.

  In one aspect of the PCV system abnormality detection device of the present invention, the detecting means is preset as a supercharging pressure of the turbocharger when the supercharging pressure specified by the supercharging pressure specifying means during the EGR control is normal. The PCV system abnormality is detected by determining whether or not the state larger than the reference supercharging pressure continues for the first predetermined time.

  According to this aspect, the detection means compares the supercharging pressure specified by the supercharging pressure specifying means during EGR control with the reference supercharging pressure, and determines the supercharging specified by the supercharging pressure specifying means during EGR control. When it is determined that the state where the pressure is greater than the reference boost pressure continues for the first predetermined time, it is determined that an abnormality has occurred in the PCV system, and is specified by the boost pressure specifying means during EGR control. When it is determined that the state in which the supercharging pressure is greater than the reference supercharging pressure has not continued for the first predetermined time, it is determined that no abnormality has occurred in the PCV system (that is, the PCV system is normal). To do. Thereby, the abnormality of the PCV system can be accurately detected. The “first predetermined time” is determined in advance by empirical, experimental, or simulation depending on the detection accuracy for detecting a PCV system abnormality as a reference for determining whether or not a PCV system abnormality has occurred. It should be determined.

  In another aspect of the PCV system abnormality detection device of the present invention, the detection means includes a supercharging pressure specified by the supercharging pressure specifying means at the time of the EGR control and a supercharging pressure of the turbocharger in a normal state in advance. The PCV system abnormality is detected by determining whether or not the time integrated value in the second predetermined time of the difference from the set reference supercharging pressure is larger than the reference time integrated value.

  According to this aspect, the detection means is configured such that the time integrated value in the second predetermined time of the difference between the supercharging pressure specified by the supercharging pressure specifying means during the EGR control and the reference supercharging pressure is greater than the reference time integrated value. When it is determined that the value is large (that is, the reference time integrated value has been exceeded), it is determined that an abnormality has occurred in the PCV system, and the supercharging pressure specified by the supercharging pressure specifying means during the EGR control and the reference overpressure are determined. If it is determined that the time integrated value at the second predetermined time of the difference from the supply pressure is equal to or less than the reference time integrated value (that is, not exceeding the reference time integrated value), no abnormality has occurred in the PCV system. (That is, the PCV system is normal). Thereby, the abnormality of the PCV system can be accurately detected. The “second predetermined time” and the “reference time integrated value” are empirically determined according to the detection accuracy for detecting the PCV system abnormality as a reference for determining whether or not the PCV system abnormality has occurred. It may be determined in advance by experiment or simulation.

  The operation and other advantages of the present invention will become apparent from the best mode for carrying out the invention described below.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, the configuration of the engine system according to the present embodiment will be described with reference to FIG.

  FIG. 1 is a block diagram showing a configuration of an engine system including a PCV system abnormality detection device according to the present embodiment.

  In FIG. 1, an engine system 10 is mounted on a vehicle (not shown) and includes an ECU 100 and an engine 200.

  The engine 200 is an in-line four-cylinder diesel engine that is an example of an “internal combustion engine” according to the present invention that uses light oil as fuel. The engine 200 has a configuration in which four cylinders 202 are arranged in parallel on a cylinder block 201. In each cylinder 202, in the compression stroke, a mixture of fuel and intake air directly injected into the cylinder during the compression stroke or the intake stroke is compressed, and the force generated when the cylinder spontaneously ignites is not shown. It is configured to be converted into a rotational motion of the crankshaft via a piston and a connecting rod. The rotation of the crankshaft is transmitted to drive wheels of a vehicle on which the engine system 10 is mounted, and the vehicle can travel.

  In the engine system 10 according to the present embodiment, the engine 200 that is a diesel engine is employed as an example of the “internal combustion engine” according to the present invention. However, the “internal combustion engine” according to the present invention includes only a diesel engine. Of course, it may be a gasoline engine or an engine using an alcohol-mixed fuel.

  In FIG. 1, intake air as air guided from the outside world is guided to the intake pipe 204. The intake pipe 204 is provided with a throttle valve 205 capable of adjusting the amount of intake air guided to the intake pipe 204. The throttle valve 205 is a rotary valve that is configured to be rotatable by a driving force supplied from a throttle valve motor (not shown) that is electrically connected to the ECU 100 and controlled by the ECU 100 at the upper level. The rotational position is continuously controlled from a fully closed position where the upstream and downstream portions of the intake pipe 204 at the boundary are substantially blocked to a fully open position where the intake pipe 204 communicates almost entirely. As described above, in the engine 200, the throttle valve 205 and the throttle valve motor constitute a kind of electronically controlled throttle device.

  Engine 200 is a diesel engine, and its output is controlled through injection amount increase / decrease control, unlike air-fuel ratio control (fuel injection control based on intake air amount) in an engine using gasoline or the like as fuel. The Therefore, the amount of intake air sucked through the throttle valve 205 is not substantially limited at least on the upper limit side, and the throttle valve 205 is basically in the most part of the operation period of the engine 200. It is controlled to the fully open position.

  The intake pipe 204 is connected to the communication pipe 206 on the downstream side of the throttle valve 205 and is configured to communicate with the communication pipe 206 therein. The communication pipe 206 communicates with each intake port (not shown) of each cylinder 202, and the intake air guided to the intake pipe 204 is guided to the intake port corresponding to each cylinder via the communication pipe 206. It is configured to be written. The intake port is configured to communicate with the inside of the cylinder 202. The intake pipe 204 (including a connecting portion 204a described later) and the communication pipe 206 constitute an example of the “intake system” according to the present invention.

  The communication state between the intake port and the cylinder 202 is controlled by an intake valve provided in each intake port. The intake valve is fixed to the intake camshaft that rotates in conjunction with the crankshaft, and its open / close characteristics are defined according to the cam profile of the intake cam, whose section perpendicular to the extension direction of the intake camshaft is elliptical. Thus, the intake port and the cylinder 202 can communicate with each other when the valve is opened. As described above, in the engine 200, the communication pipe 206 is concentrated on the upstream side of the portion corresponding to each cylinder 202 (more specifically, the intake port), so that a so-called single valve type intake manifoldless intake system is realized. Yes.

  A fuel injection valve as a part of an in-cylinder injector is exposed inside the cylinder 202, and is configured so that light oil as fuel can be directly injected into a high-temperature and high-pressure cylinder.

  The air-fuel mixture formed inside the cylinder 202 is self-ignited and burned in the compression stroke, and is an exhaust valve that opens and closes in conjunction with the opening and closing of the intake valve as a burned gas or a partially unburned air-fuel mixture. When the valve is opened, the exhaust gas is guided to the exhaust manifold 213 through the exhaust port (not shown) as exhaust gas.

  The engine 200 includes a turbocharger 218. The darbocharger 218 includes a turbine 218a and a compressor 218b. The turbine 218 a is disposed in the exhaust pipe 214, and the compressor 218 b is disposed in the intake passage 204. The turbocharger 218 operates the compressor 218b by the rotational energy of the turbine 218a through which the exhaust gas passes. The compressor 218b is configured to be able to pump and supply intake air sucked into the intake pipe 204 from the outside via an air cleaner (A / C) 219 to the downstream side by the pressure accompanying the rotation. The supercharging is realized by the pressure feeding effect of the intake air by 218b.

  An intercooler 221 is installed in the intake pipe 204 downstream of the compressor 218 b and upstream of the throttle valve 205. The intercooler 221 has a heat exchange wall inside thereof, and when the supercharged intake air passes (similarly in a low rotation region where the compressor 218b does not act substantially), The intake air can be cooled by heat exchange via the heat exchange wall. The engine 200 can increase the density of the intake air by the cooling by the intercooler 221, so that the supercharging via the compressor 218b can be performed more efficiently.

  A pressure sensor 230 that can specify the supercharging pressure of the turbocharger 218 is provided in the intake pipe 204 on the downstream side of the compressor 218 b and the upstream side of the intercooler 221. The pressure sensor 230 transmits a signal indicating the specified supercharging pressure to the ECU 100. The pressure sensor 230 is an example of the “supercharging pressure specifying unit” according to the present invention.

  An air flow meter is provided on the intake pipe 204 downstream of the air cleaner 219 and upstream of the compressor 218b (more specifically, upstream of the connecting portion 204a where the intake pipe 204 and the PCV pipe 271 are connected to each other). (AFM: Air Flow Meter) 220 is provided. The air flow meter 220 measures the flow rate of air taken into the intake pipe 204 from the outside (that is, the amount of intake air). The air flow meter 220 transmits a signal indicating the measured amount of intake air to the ECU 100.

  The engine 200 is provided with an EGR passage 240 that communicates the exhaust manifold 213 and the intake pipe 204 (more specifically, the downstream side of the throttle valve 205 in the intake pipe 204). Exhaust gas guided from the exhaust manifold 213 to the EGR passage 240 is recirculated to the intake pipe 204 as EGR gas. An EGR cooler 241 is installed in the middle of the EGR passage 240. The EGR cooler 241 is a cooling device that cools the EGR gas. An EGR valve 242 is provided downstream of the EGR cooler 241 in the EGR passage 240. The EGR valve 242 is a valve mechanism including a valve body that can be opened and closed and a drive device that drives the valve body. The valve body of the EGR valve 242 is configured so that the open / close state is continuously changed by the driving device, and the flow rate of the EGR gas flowing through the EGR passage 240 according to the open / close state (that is, the EGR gas flow rate). It is possible to control. The drive device of the EGR valve 242 is electrically connected to the ECU 100, and the open / close state of the valve body of the EGR valve 242 is controlled by the ECU 100 to the upper level. That is, the opening degree of the valve body of the EGR valve 242 (that is, the EGR valve opening degree) is configured to be controlled higher by the ECU 100 (more specifically, the EGR control unit 110 described later).

  A DPNR (Diesel Particulate NOx Reduction system) 228 is installed in the exhaust pipe 214. The DPNR 228 is an exhaust purification device and has a DPF 228a. More specifically, the DPNR 228 includes a CCO (oxidation catalyst) (not shown), a DPF 228a, and an NSR catalyst (not shown) arranged in parallel in the exhaust flow direction. The DPF 228a is a filter configured to be able to capture PM (Particulate Matter: particulate matter) in the exhaust gas.

  In FIG. 1, the engine 200 is provided with a PCV pipe 271. The PCV pipe 271 draws blow-by gas sucked out from a crankcase or the like below the cylinder 202 via the inside of the cylinder head located above the cylinder block 201 or the like, into the intake pipe 204 (more specifically, the intake pipe In 204, it is a metallic tubular member which becomes a blow-by gas passage for recirculation to the upstream side of the compressor 218b and the downstream side of the air cleaner 219). The PCV pipe 271 is connected to an oil separator 276 that separates blow-by gas and oil in the crankcase from each other. The blow-by gas separated by the oil separator 276 passes through the PCV pipe 271 and returns to the intake pipe 204. The PCV pipe 271 and the oil separator 276 constitute an example of the “PCV system” according to the present invention.

  The ECU 100 is an electronic control unit that includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like and is configured to be able to control the entire operation of the engine 200.

  Particularly in the present embodiment, the ECU 100 includes an EGR control unit 110 and a detection unit 120.

  The EGR control unit 110 is an example of the “EGR control unit” according to the present invention, and performs feedback control of the EGR valve 242 based on the air flow rate measured by the air flow meter 220. For example, when the flow rate of air measured by the air flow meter 220 is less than a predetermined flow rate, the EGR control unit 110 has an excessive amount of EGR gas (that is, the EGR passage 240 is currently recirculated to the intake pipe 204 by the EGR passage 240. The EGR valve 242 is controlled so as to decrease the flow rate of the ERG gas. That is, when the air flow rate measured by the air flow meter 220 is less than the predetermined flow rate, the EGR control unit 110 controls the valve body of the EGR valve 242 to the closed side in order to reduce the ERG gas flow rate ( That is, the EGR valve opening is reduced).

  The detection unit 120 detects an abnormality in the PCV piping 271 based on the boost pressure specified by the pressure sensor 230 during the EGR control by the EGR control unit 110 in an operation range where the boost pressure of the turbocharger 218 is open-loop controlled. To detect.

  Next, detection of an abnormality of the PVC pipe in the present embodiment will be described with reference to FIG. 2 in addition to FIG.

  FIG. 2 is a flowchart showing a flow of detection of abnormality of the PCV piping in the present embodiment.

  In FIG. 1 and FIG. 2, for example, when the PCV piping 271 is damaged or the PCV piping 271 is disconnected from the oil separator 276 or the intake pipe 204, an abnormality occurs in the PCV piping 271 (step S10). Outside air flows in from the portion where the abnormality has occurred in the PCV piping 271, and accordingly, the flow rate of air flowing through the intake pipe 204 (more specifically, upstream from the connecting portion 204 a) (in other words, from the outside through the air cleaner 219). The amount of air taken in) decreases. Along with this, the flow rate of air measured by the air flow meter 220 (in other words, the detected value detected by the air flow meter 220) also decreases (step S20).

  At this time, when the air flow rate measured by the air flow meter 220 is less than the predetermined flow rate, the EGR control unit 110 has an excessive amount of EGR gas (that is, the EGR passage 240 is currently recirculated to the intake pipe 204 by the EGR passage 240). It is determined that there is too much EGR gas as compared with the EGR gas in the normal state) (step S30).

  When the EGR control unit 110 determines that the EGR gas is excessive, the EGR control unit 110 controls the EGR valve 242 so as to decrease the flow rate of the ERG gas (step S40). That is, the EGR control unit 110 controls the valve body of the EGR valve 242 to the closed side so as to reduce the flow rate of the ERG gas.

  When the flow rate of the EGR gas is decreased by the control of the EGR valve 242 by the EGR control unit 110, the flow rate of the exhaust gas flowing into the turbocharger 218 (more specifically, the turbine 218a) is increased accordingly ( Step S50). For this reason, the rotational energy of the turbine 218a increases, and the supercharging pressure of supercharging by the turbocharger 218 increases (step S60).

  Here, in the present embodiment, in particular, the detection unit 120 of the ECU 100 determines that the supercharging pressure Pim specified by the pressure sensor 230 is greater than the reference supercharging pressure Pim_Hi set in advance as the supercharging pressure of the turbocharger 218 during normal operation. Of the PCV pipe 271 is detected by determining whether or not a state in which the pressure is larger (that is, a state where the supercharging pressure Pim> the reference supercharging pressure Pim_Hi) continues for a predetermined time.

  That is, first, the detection unit 120 determines whether or not the supercharging pressure Pim specified by the pressure sensor 230 is greater than the reference supercharging pressure Pim_Hi (step S70). When it is determined that the supercharging pressure Pim is larger than the reference supercharging pressure Pim_Hi (step S70: Yes), the detection unit 120 continues the state where the supercharging pressure Pim is larger than the reference supercharging pressure Pim_Hi for a predetermined time. It is determined whether or not (step S80). On the other hand, when it is determined that the supercharging pressure Pim is equal to or lower than the reference supercharging pressure Pim_Hi (step S70: No), after each processing from step S20 to step S60 is performed again, the detection unit 120 is again performed. Thus, it is determined whether or not the supercharging pressure Pim is larger than the reference supercharging pressure Pim_Hi (step S70).

  When it is determined that the state where the supercharging pressure Pim is larger than the reference supercharging pressure Pim_Hi continues for a predetermined time (step S80: Yes), the detection unit 120 has an abnormality in the PCV piping 271. That is, abnormality of the PCV piping 271 is detected (step S90). On the other hand, when it is determined that the state in which the supercharging pressure Pim is greater than the reference supercharging pressure Pim_Hi has not continued for a predetermined time (step S80: No), each process related to step S20 to step S60 is performed again. After that, the detection unit 120 determines again whether or not the supercharging pressure Pim is larger than the reference supercharging pressure Pim_Hi (step S70).

  Thus, according to the present embodiment, when an abnormality occurs in the PCV piping 271 (step S10), the flow rate of the EGR gas is reduced by the control of the EGR valve 242 by the EGR control unit 110 (step S40). In addition, by utilizing the fact that the supercharging pressure of the turbocharger 218 increases (step S60), the abnormality of the PCV pipe 271 can be accurately detected by the detection unit 120.

  In the present embodiment, the detection unit 120 has a state where the supercharging pressure Pim specified by the pressure sensor 230 is larger than the reference supercharging pressure Pim_Hi preset as the supercharging pressure of the turbocharger 218 at the normal time. Although it is configured to detect the abnormality of the PCV pipe 271 by determining whether or not it continues for a predetermined time, as a modified example of this embodiment, the detection unit 120 is excessively specified by the pressure sensor 230. A time integrated value at a predetermined time of a difference between the supply pressure Pim and a reference supercharging pressure Pim_Hi set in advance as a supercharging pressure of the turbocharger 218 in a normal state (that is, supercharging pressure Pim−reference supercharging pressure Pim_Hi) is Alternatively, it may be configured to detect an abnormality in the PCV piping 271 by determining whether or not the integrated value is larger than the reference time integrated value. That is, in FIG. 2, instead of the process according to step S80, it is determined whether or not the time integrated value at a predetermined time of the difference between the supercharging pressure Pim and the reference supercharging pressure Pim_Hi is larger than the reference time integrated value. Processing may be performed by the detection unit 120. In this case, when it is determined that the time integrated value at a predetermined time of the difference between the supercharging pressure Pim and the reference supercharging pressure Pim_Hi is larger than the reference time integrated value, the detection unit 120 applies the PCV pipe 271 to the PCV pipe 271. By determining that an abnormality has occurred, an abnormality in the PCV pipe 271 can be accurately detected.

  As described above, according to the present embodiment, an abnormality of the PCV pipe 271 provided in the engine 200 can be accurately detected.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification, and PCV abnormality detection with such a change is possible. The apparatus is also included in the technical scope of the present invention.

It is a block diagram which shows the structure of the engine system provided with the PCV type | system | group abnormality detection apparatus which concerns on this embodiment. It is a flowchart which shows the flow of detection of abnormality of PCV piping in this embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 ... ECU, 110 ... EGR control part, 120 ... Detection part, 200 ... Engine, 202 ... Cylinder, 204 ... Intake pipe, 218 ... Turbocharger, 218a ... Turbine, 218b ... Compressor, 219 ... Air cleaner, 220 ... Air flow meter , 230 ... Pressure sensor, 240 ... EGR passage, 241 ... EGR cooler, 242 ... EGR valve, 271 ... PCV piping

Claims (3)

A PCV system abnormality detection device for detecting an abnormality of a PCV system for recirculating blowby gas in a crankcase of an internal combustion engine to an intake system of the internal combustion engine,
A turbocharger that performs supercharging using the exhaust gas of the internal combustion engine;
An EGR passage for recirculating a part of the exhaust gas to the intake system as EGR gas;
An EGR valve provided in the ERG passage and capable of adjusting a flow rate of the EGR gas;
An air flow meter for measuring a flow rate of air sucked into the intake system;
EGR control means for performing EGR control for controlling the EGR valve so as to decrease the flow rate of the ERG gas when the flow rate of air measured by the air flow meter is smaller than a predetermined flow rate;
A supercharging pressure specifying means for specifying a supercharging pressure of the turbocharger;
A PCV system abnormality detection apparatus comprising: a detection unit that detects an abnormality of the PCV system based on a boost pressure specified by the boost pressure specifying unit during the EGR control.   The detection means is in a state where the supercharging pressure specified by the supercharging pressure specifying means during the EGR control is larger than a reference supercharging pressure set in advance as a supercharging pressure of the turbocharger when normal. The PCV system abnormality detection device according to claim 1, wherein the PCV system abnormality is detected by determining whether or not the operation continues for a predetermined time.   The detecting means has a second predetermined difference between a supercharging pressure specified by the supercharging pressure specifying means at the time of the EGR control and a reference supercharging pressure preset as a turbocharging pressure of the turbocharger during normal operation. 2. The PCV system abnormality detection device according to claim 1, wherein the PCV system abnormality is detected by determining whether or not a time integrated value in time is larger than a reference time integrated value.

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