JP6494822B1 - Control device for internal combustion engine and control method for internal combustion engine - Google Patents

Abstract

An internal combustion engine control apparatus and an internal combustion engine control method capable of detecting an abnormality of a PCV valve are provided. According to a comparison between an oxygen concentration value inside an intake manifold during operation of an internal combustion engine and an oxygen concentration determination value, it is determined whether there is an abnormality in a PCV valve provided in a blow-by gas passage. I made it. [Selection] Figure 2

Description

  The present invention relates to a control device for an internal combustion engine including a blow-by gas reduction device, and a control method for the internal combustion engine.

  Exhaust gas and unburned gas that have become high pressure in the cylinder of the internal combustion engine may leak into the crankcase of the internal combustion engine through a gap between the piston and the cylinder. The gas leaking into the crankcase is referred to as blow-by gas, and blow-by gas causes air pollution if released into the atmosphere as it is. Therefore, there is a case where the internal combustion engine is provided with a blow-by gas reduction device that reduces the blow-by gas to the intake system of the internal combustion engine and re-combusts it in the combustion chamber of the internal combustion engine.

  The blow-by gas reduction device is a blow-by gas passage formed by connecting the inside of the crankcase of the internal combustion engine and the downstream side of the throttle valve of the intake system with a rubber hose or the like in order to distribute the blow-by gas to the intake system of the internal combustion engine. And a PCV (Positive Crankcase Ventilation) valve as a check valve is mounted in the blow-by gas passage.

  In the case of a PCV valve having a mechanical configuration, a valve body disposed between one open end and the other open end and a spring that constantly biases the valve body in a closing direction are provided. The PCV valve configured in this way is mounted in series in the blow-by gas passage so that the one end faces the inside of the crankcase and the other end faces the intake system.

  The PCV valve installed in the blow-by gas passage opens the valve body when the pressure in the crankcase exceeds the total pressure of the downstream side of the throttle valve in the intake system and the spring pressure of the spring. Gas is circulated to the intake system via the blow-by gas passage. On the contrary, when the pressure in the crankcase is equal to or lower than the total pressure of the downstream pressure of the throttle valve and the spring pressure of the spring in the intake system, the valve body is closed and the blow-by gas passage is shut off to blow-by gas. To stop the aforementioned distribution.

  The opening degree of the PCV valve is determined according to the pressure difference between the pressure in the crankcase and the total pressure of the pressure on the downstream side of the throttle valve and the pressing force of the spring in the intake system. The amount depends on the opening of the PCV valve.

  However, in the case of a PCV valve with a mechanical configuration configured as described above, the pressing force of the spring, which is a mechanical component, has a large variation in manufacturing, and even if the operating conditions of the internal combustion engine are the same, Differences in the flow rate of blow-by gas may occur depending on the individual PCV valves.

  In addition, when a PCV valve with a low-cost mechanical configuration is used, it does not have an output for monitoring the PCV valve operating status such as the opening of the PCV valve. However, it is difficult to detect the abnormality.

  On the other hand, for example, according to the conventional blow-by gas reduction device disclosed in Patent Document 1, a PCV valve that enables adjustment of the flow rate of the blow-by gas is used, and the blow-by gas is reduced according to the operating state of the internal combustion engine. The flow rate is adjusted, and the PCV valve abnormality is detected based on the flow rate adjustment state by the PCV valve, the intake air amount state of the internal combustion engine, and the like.

  Further, for example, in the blow-by gas passage abnormality detection device for an internal combustion engine disclosed in Patent Document 2, an abnormality such as leakage or omission in the blow-by gas passage is detected based on an air control amount during idle operation of the internal combustion engine. ing.

JP 2017-145782 A Japanese Patent Laid-Open No. 10-184335

  In the case of the control device for an internal combustion engine provided with the conventional blow-by gas reduction device disclosed in Patent Document 1, it is necessary to use a PCV valve that can arbitrarily adjust the flow rate of blow-by gas. Since a control means for driving and controlling the PCV valve is also required, there is a problem in that the cost is increased. Further, in the case of the control device for an internal combustion engine provided with the blow-by gas passage abnormality detection device disclosed in the above-mentioned Patent Document 2, although the system configuration is inexpensive, a closed failure in which the valve body of the PCV valve is fixed in the closed position. There was a problem that anomalies based on this could not be detected.

  The present invention has been made to solve the above-described problems in a control device for an internal combustion engine equipped with a conventional blow-by gas reduction device, and even if a mechanically configured PCV valve is used, An object of the present invention is to provide a control device for an internal combustion engine and a control method for the internal combustion engine that can reliably detect the abnormality.

An internal combustion engine control apparatus according to the present invention includes:
A blow-by gas passage through which the blow-by gas inside the crankcase of the internal combustion engine flows to the downstream side of the throttle valve in the intake system of the internal combustion engine;
A PCV valve that is provided in the blow-by gas passage and opens and closes depending on the pressure inside the crankcase;
Have
A control device for an internal combustion engine configured to control a flow of the blow-by gas based on an opening / closing operation of the PCV valve;
A valve device arranged in series with the PCV valve in the blow-by gas passage and capable of opening and closing the blow-by gas passage;
An operating state detection unit that detects an oxygen concentration of a gas downstream of a connection portion with the blow-by gas passage in the intake system;
The value of the oxygen concentration during operation of the internal combustion engine detected by the operating state detection unit, and the amount of change in the oxygen concentration that occurs when the valve device is opened or closed during operation of the internal combustion engine, , based on, and is configured to determine the presence or absence of abnormality of the PCV valve,
It is characterized by that.

The control method of the internal combustion engine of the present invention includes:
The blow-by gas inside the crankcase of the internal combustion engine is circulated to the downstream side of the throttle valve in the intake system of the internal combustion engine through the blow-by gas passage. A control method for an internal combustion engine that is controlled,
Provided in series with the PCV valve in the blow-by gas passage during operation of the internal combustion engine and the value of the oxygen concentration of the gas downstream of the connection portion of the intake system with the blow-by gas passage Determining whether there is an abnormality in the PCV valve based on the amount of change in the oxygen concentration of the intake system that is caused by opening or closing the valve device
It is characterized by that.

According to the control apparatus for an internal combustion engine according to the present invention, the blow-by gas inside the crankcase of the internal combustion engine is circulated to the downstream side of the throttle valve in the intake system of the internal combustion engine, and the blow-by gas path And a PCV valve that opens and closes depending on the pressure inside the crankcase, and controls the flow of the blow-by gas based on the opening and closing operation of the PCV valve. A control device,
An operating state detection unit that detects an oxygen concentration of a gas downstream of the throttle valve in the intake system, and based on the value of the oxygen concentration during operation of the internal combustion engine detected by the operating state detection unit, Since it is configured to determine whether there is an abnormality in the PCV valve, the abnormality can be reliably detected even with a mechanically configured PCV valve.

  Further, according to the control device for an internal combustion engine according to the present invention, the blow-by gas passage for allowing the blow-by gas inside the crankcase of the internal combustion engine to flow downstream of the throttle valve in the intake system of the internal combustion engine, and the blow-by gas An internal combustion engine that is provided in a passage and that opens and closes depending on a pressure inside the crankcase, and controls the flow of the blow-by gas based on the opening and closing operation of the PCV valve. An engine control device, which is arranged in series with the PCV valve in the blow-by gas passage and can open and close the blow-by gas passage; and an oxygen concentration of a gas downstream of the throttle valve in the intake system An operating state detecting unit for detecting the oxygen during operation of the internal combustion engine detected by the operating state detecting unit; Based on the degree value and the amount of change in the oxygen concentration that occurs when the valve device is opened or closed during operation of the internal combustion engine, the presence or absence of an abnormality in the PCV valve is determined. Since it is configured, it is possible to detect the abnormality more reliably even with a mechanically configured PCV valve.

  Further, according to the control method for an internal combustion engine according to the present invention, the blowby gas inside the crankcase of the internal combustion engine is circulated to the downstream side of the throttle valve in the intake system of the internal combustion engine through the blowby gas passage, and the blowby gas Is controlled by a PCV valve provided in the blow-by gas passage, wherein the PCV is based on the value of oxygen concentration in the intake system during operation of the internal combustion engine. Since the presence / absence of abnormality of the valve is determined, even the mechanically configured PCV valve can reliably detect the abnormality.

  Further, according to the control method for an internal combustion engine according to the present invention, the blowby gas inside the crankcase of the internal combustion engine is circulated to the downstream side of the throttle valve in the intake system of the internal combustion engine through the blowby gas passage, and the blowby gas Is controlled by a PCV valve provided in the blow-by gas passage, the oxygen concentration value of the intake system during operation of the internal combustion engine, and the internal combustion engine The abnormality of the PCV valve based on the amount of change in the oxygen concentration of the intake system caused by rotating or closing the valve device provided in series with the PCV valve in the blow-by gas passage during operation Therefore, even if it is a mechanically configured PCV valve, its abnormality can be detected more reliably. Can.

1 is a schematic configuration diagram of a control device for an internal combustion engine according to Embodiment 1 of the present invention. FIG. 1 is a block diagram of a control device for an internal combustion engine according to Embodiment 1 of the present invention. FIG. It is a hardware block diagram of the control apparatus of the internal combustion engine which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows the oxygen concentration of the gas in an intake manifold for demonstrating the control apparatus of the internal combustion engine which concerns on Embodiment 1 of this invention, and the control method of an internal combustion engine. 2 is a flowchart for illustrating a control device for an internal combustion engine and a control method for the internal combustion engine according to Embodiment 1 of the present invention.

Embodiment 1 FIG.
Hereinafter, a control device and a control method for an internal combustion engine according to Embodiment 1 of the present invention will be described in detail with reference to the drawings. 1 is a schematic configuration diagram of an internal combustion engine control apparatus according to Embodiment 1 of the present invention, FIG. 2 is a block diagram of the internal combustion engine control apparatus according to Embodiment 1 of the present invention, and FIG. It is a hardware block diagram of the control apparatus of the internal combustion engine which concerns on Embodiment 1 of invention. 1, 2, and 3, the internal combustion engine 1 and the control device 50 that controls the internal combustion engine 1 are mounted on a vehicle. The internal combustion engine 1 serves as a driving force source that drives driving wheels of the vehicle.

  First, the configuration of the internal combustion engine 1 will be described. The internal combustion engine 1 has a cylinder 25 that burns a mixture of air and fuel. The internal combustion engine 1 includes an intake passage 23 that supplies air to the cylinder 25 and an exhaust passage 17 that discharges exhaust gas burned in the cylinder 25. The internal combustion engine 1 includes a throttle valve 6 that opens and closes an intake passage 23. The throttle valve 6 is an electronically controlled throttle valve that is driven to open and close by an electric motor controlled by the control device 50. The throttle valve 6 is provided with a throttle opening sensor 7 that outputs an electrical signal corresponding to the opening of the throttle valve 6.

  An air cleaner 24 that purifies the air sucked into the intake passage 23 is provided at the most upstream portion of the intake passage 23. In the intake passage 23 upstream of the throttle valve 6, an air flow sensor 3 that outputs an electric signal according to the flow rate of intake air that is air sucked into the intake passage 23 from the atmosphere, and intake air that is the temperature of the intake air. An intake air temperature sensor 4 that outputs an electrical signal corresponding to the temperature Ta and an intake air humidity sensor 5 that outputs an electrical signal corresponding to the intake air humidity Ha, which is the humidity of the intake air, are provided.

  The pressure in the intake passage 23 on the upstream side of the throttle valve 6 can be regarded as being equal to the atmospheric pressure. An intake air pressure sensor 2 that outputs an electric signal corresponding to the intake air pressure Pa that is the pressure of the intake air (in the first embodiment, the atmosphere) is provided outside the intake passage 23 (for example, inside the control device 50). It has been.

  The intake air temperature sensor 4 and the intake air humidity sensor 5 may be integrated with the air flow sensor 3 or may be separated. Alternatively, the intake air temperature sensor 4 and the intake air humidity sensor 5 may be provided outside the intake passage 23 in the same manner as the intake air pressure sensor 2. In any case, the intake air pressure sensor 2, the intake air temperature sensor 4, and the intake air humidity sensor 5 are places where intake air sucked into the intake passage 23 exists, and the pressure of the intake air is substantially reduced. Provided in the same place.

  An intake manifold 12 is provided in the intake passage 23 on the downstream side of the throttle valve 6. A surge tank 11 for suppressing intake pulsation is provided in the intake passage 23 between the upstream side of the intake manifold 12 and the downstream side of the throttle valve 6. The internal combustion engine 1 includes an EGR (Exhaust Gas Recirculation) passage 21 that recirculates exhaust gas from the exhaust passage 17 to the surge tank 11, and an EGR valve 22 that opens and closes the EGR passage 21. The intake passage 23, the surge tank 11, and the intake manifold 12 described above constitute an intake system of the internal combustion engine 1.

  In the first embodiment, the EGR passage 21 is provided between the exhaust passage 17 and the surge tank 11, but may be provided between the exhaust passage 17 and the intake manifold 12.

  The EGR valve 22 is configured by an electronically controlled EGR valve that is opened and closed by an electric actuator such as an electric motor controlled by the control device 50. The exhaust gas recirculated to the surge tank 11 (hereinafter referred to as recirculated exhaust gas) and the intake air sucked into the surge tank 11 are mixed and made uniform in the surge tank 11.

  The surge tank 11 connected to the intake manifold 12 has a manifold pressure sensor 8 that outputs an electric signal corresponding to the manifold pressure Pb that is the gas pressure in the intake manifold 12, and the gas temperature in the intake manifold 12. A manifold temperature sensor 9 for outputting an electrical signal corresponding to a certain manifold temperature Tb, an in-manifold oxygen concentration sensor 10 for outputting an electrical signal corresponding to the oxygen concentration Rox_in in the manifold, which is the oxygen concentration of the gas in the intake manifold 12, and Is provided.

  Note that the pressure, temperature, and oxygen concentration of the gas in the surge tank 11 are the same as the pressure, temperature, and oxygen concentration of the gas in the intake manifold 12, and in the first embodiment, the manifold pressure sensor 8 and the manifold temperature sensor. 9 and the oxygen concentration sensor 10 in the manifold are all installed in the surge tank 11, but at least one of them may be installed in the intake manifold 12. The manifold temperature sensor 9 and the in-manifold oxygen concentration sensor 10 may be integrated with the manifold pressure sensor 8 or may be separated.

  The manifold temperature sensor 9 and the in-manifold oxygen concentration sensor 10 are provided downstream of the connection portion between the intake manifold 12 and the EGR passage, and the temperature and oxygen of the gas in which the intake air and the recirculated exhaust gas are sufficiently mixed are provided. It is configured so that the concentration can be detected.

  An injector 13 for injecting fuel is provided at a downstream portion of the intake manifold 12. The injector 13 may be provided so as to inject fuel directly into the cylinder 25.

  A spark plug 161 that ignites an air-fuel mixture and an ignition coil 16 that supplies ignition energy to the spark plug 161 are provided at the top of the cylinder 25. Also, at the top of the cylinder 25, an intake variable valve timing mechanism 14 that varies the valve opening / closing timing of an intake valve that adjusts the amount of intake air that is drawn into the cylinder 25 from the intake passage 23, and an exhaust passage 17 from the cylinder. There is provided an exhaust variable valve timing mechanism 15 that varies the valve opening / closing timing of the exhaust valve for adjusting the amount of exhaust gas discharged to the exhaust gas. The intake variable valve timing mechanism 14 and the exhaust variable valve timing mechanism 15 have electric actuators.

  The crankshaft of the internal combustion engine 1 is provided with a crank angle sensor 20 that outputs an electrical signal corresponding to the rotation angle. The exhaust passage 17 is provided with an air-fuel ratio sensor 18 that outputs an electric signal corresponding to an air-fuel ratio AF (Air / Fuel) that is a ratio of air and fuel in the exhaust gas. The exhaust passage 17 is provided with a catalyst 19 for purifying the exhaust gas. As the catalyst 19, a three-way catalyst having high purification performance in the vicinity of the theoretical air-fuel ratio AF0 is used.

  The crankcase 26 is integrated with the oil pan and has a space inside. The crankshaft 100 of the internal combustion engine 1 is disposed in the space inside the crankcase 26. The intake variable valve timing mechanism 14 and the exhaust variable valve timing mechanism 15 described above are covered with a head cover 27. The space inside the head cover 27 and the space inside the crankcase 26 described above are communicated by the gas passage 110, and the space inside the head cover 27, the space inside the crankcase 26, and the space inside the gas passage 110. Becomes a blow-by gas accumulating section for accumulating blow-by gas.

  The head cover 27 is connected to the intake passage 23 located upstream of the throttle valve 6 by a fresh air introduction passage 28. The crankcase 26 and the surge tank 11 are connected by a blow-by gas passage 29 via a PCV valve 30. A BV (Butterfly Valve) 31 that opens and closes the blow-by gas passage 29 is connected between the PCV valve 30 and the crankcase 26. The BV 31 is controlled by the control device 50 to open and close the blow-by gas passage 29.

  Next, the control device 50 will be described. The control device 50 is a control device that controls the internal combustion engine 1. As shown in FIG. 2, the control device 50 includes an operating state detection unit 51, an oxygen concentration determination unit 52, an oxygen concentration change amount determination unit 53, and a PCV valve closing failure determination unit 54. The aforementioned operating state detection unit 51, oxygen concentration determination unit 52, oxygen concentration change amount determination unit 53, and PCV valve closing failure determination unit 54 in the control device 50 are realized by a processing circuit provided in the control device 50.

  Specifically, as shown in FIG. 3, the control device 50 can read data from the arithmetic processing device 90, which is a computer configured with a CPU (Central Processing Unit) as a processing circuit, and the arithmetic processing device 90. A storage device 911 configured as a ROM (Read Only Memory), a storage device 912 configured as a RAM (Random Access Memory) configured to be able to read and write data from the processing unit 90, and external to the processing unit 90 Are provided with an input circuit 92 for inputting the signal, an output circuit 93 for outputting a signal from the arithmetic processing unit 90 to the outside, and a communication circuit 94 for the arithmetic processing unit 90 to perform data communication with the external device.

  The input circuit 92 includes an intake air pressure sensor 2, an air flow sensor 3, an intake air temperature sensor 4, an intake air humidity sensor 5, a throttle valve 6 operated by an electric motor, a throttle opening sensor 7, a manifold pressure sensor 8, and a manifold temperature sensor. 9, an in-manifold oxygen concentration sensor 10, an air-fuel ratio sensor 18, a crank angle sensor 20, and a switch (not shown) are connected. The input circuit 92 includes an A / D converter (not shown) that inputs the output signals of these sensors and switches to the arithmetic processing unit 90.

  The output circuit 93 is connected to an electrical load, and includes a drive circuit that outputs a control signal from the arithmetic processing unit 90 to the electrical load. Examples of the electric load connected to the output circuit 93 include the throttle valve 6, the injector 13, the intake variable valve timing mechanism 14, the exhaust variable valve timing mechanism 15, the ignition coil 16, the EGR valve 22, and the BV31. In-vehicle electronic devices such as an air conditioner control device 80 and a transmission control device 81 are connected to the communication circuit 94 via a communication line. The communication circuit 94 performs wired communication with in-vehicle electronic devices such as the air conditioner control device 80 and the transmission control device 81 based on a communication protocol such as CAN (Controller Area Network).

Each function of the above-described operation state detection unit 51, oxygen concentration determination unit 52, oxygen concentration change amount determination unit 53, and PCV valve closing failure determination unit 54 provided in the control device 50 is stored in the ROM 90 by the arithmetic processing unit 90. The software (program) stored in the device 911 is executed and cooperates with other hardware in the control device 50 such as the storage device 911, the storage device 912 as a RAM, the input circuit 92, the output circuit 93, and the communication circuit 94. It is realized by doing. In addition,
Setting data such as characteristic data and determination values used by the operating state detection unit 51, the oxygen concentration determination unit 52, the oxygen concentration change amount determination unit 53, the PCV valve closing failure determination unit 54, and the like are part of the software (program). Are stored in a storage device 911 as a ROM.

  In the first embodiment, the input circuit 92 includes an intake air pressure sensor 2, an air flow sensor 3, an intake air temperature sensor 4, an intake air humidity sensor 5, a throttle opening sensor 7, a manifold pressure sensor 8, a manifold temperature sensor 9, An in-manifold oxygen concentration sensor 10, an air-fuel ratio sensor 18, a crank angle sensor 20, and an accelerator position sensor (not shown) for detecting the amount of accelerator depression by the driver are connected. As described above, the throttle valve 6, the injector 13, the intake variable valve timing mechanism 14, the exhaust variable valve timing mechanism 15, the ignition coil 16, the EGR valve 22, and the BV 31 are connected to the output circuit 93.

  The control device 50 is connected to various sensors, switches, actuators, and the like (not shown) in addition to the various sensors and electrical loads described above.

  As a basic control, the control device 50 calculates the fuel injection amount, the ignition timing, and the like based on the input output signals of various sensors, and drives and controls the injector 13, the ignition coil 16, and the like. The control device 50 calculates the output torque of the internal combustion engine 1 requested by the driver based on the output signal of the accelerator position sensor and the like, and adjusts the throttle valve so that the intake air amount for realizing the required output torque is obtained. Control 6 etc. At this time, an output torque of the internal combustion engine 1 calculated based on a control recirculation exhaust gas flow rate Qes, which will be described later, may be taken into consideration. Specifically, the control device 50 calculates the target throttle opening, and the electric motor of the throttle valve 6 so that the throttle opening detected based on the output signal of the throttle opening sensor 7 approaches the target throttle opening. Is controlled.

<Configuration / Operation of Operation State Detection Unit 51>
Next, the configuration and operation of the operating state detection unit 51 will be described. The driving state detection unit 51 is configured to detect the driving states of the internal combustion engine 1 and the vehicle, and detects various driving states based on output signals of various sensors. More specifically, the operation state detection unit 51 detects the manifold pressure Pb, the manifold temperature Tb, and the in-manifold oxygen concentration Rox_in, and detects the manifold pressure Pb based on the output signal of the manifold pressure sensor 8. Further, the operation state detection unit 51 detects the manifold temperature Tb based on the output signal of the manifold temperature sensor 9 and detects the oxygen concentration Rox_in in the manifold based on the output signal of the oxygen concentration sensor 10 in the manifold.

  Further, the operating state detection unit 51 detects the intake air pressure Pa, the intake air temperature Ta, and the intake air humidity Ha. In the first embodiment, the operation state detector 51 detects the intake air pressure Pa based on the output signal of the intake air pressure sensor 2. The operating state detector 51 detects the intake air temperature Ta based on the output signal of the intake air temperature sensor 4. Further, the operating state detection unit 51 detects the intake air humidity Ha based on the output signal of the intake air humidity sensor 5. Since the sensor for detecting the intake air humidity based on the relative humidity is generally used, the intake air humidity sensor 5 in the first embodiment is also configured to detect the intake air humidity using the relative humidity.

  Further, the operating state detection unit 51 detects the throttle opening based on the output signal of the throttle opening sensor 7, detects the air-fuel ratio AF of the exhaust gas based on the output signal of the air-fuel ratio sensor 18, and the crank angle sensor The rotational speed Ne of the internal combustion engine 1 is detected based on the output signal of 20, and the accelerator opening is detected based on the output signal of the accelerator position sensor.

  Further, the operating state detection unit 51 detects the intake air flow rate Qa based on the output signal of the air flow sensor 3. That is, as shown in the following formula (1), the operation state detection unit 51 is based on the intake air flow rate Qa [g / s] for one stroke (for example, before the top dead center of the piston of the internal combustion engine 1). The intake air amount QA [g / stroke] taken into the intake manifold 12 of the intake system is calculated during a period in which the piston makes one reciprocation between the angles BTDC5degCA of the crankshaft 100). Then, the operating state detection unit 51 performs a first-order lag filter process that simulates the delay in the intake manifold 12 and the surge tank 11 with respect to the intake air amount QA, and applies the first delay to the cylinder 25 during the aforementioned first stroke of the internal combustion engine. The cylinder intake air amount QAc [g / stroke] taken in is calculated. That is, the operating state detection unit 51 calculates the intake air amount QA by, for example, multiplying the intake air flow rate Qa by the one-stroke period ΔT.

ここで、ＫＣＣＡは、予め設定されたフィルタゲイン、（ｎ）は、今回の演算周期の値、（ｎ−１）は、前回の演算周期の値であることを表す。

Here, KCCA represents a preset filter gain, (n) represents the value of the current computation cycle, and (n-1) represents the value of the previous computation cycle.

Further, the operation state detection unit 51 divides the cylinder intake air amount QAc by a value obtained by multiplying the air density ρ0 in the standard atmospheric state by the cylinder volume Vc, and the charging efficiency Ec of the intake air is expressed by the following equation (2). ). The charging efficiency Ec is the ratio of the cylinder intake air amount QAc to the air mass (ρ0 × Vc) in the standard atmospheric state that satisfies the cylinder volume Vc. The standard atmospheric condition is 1 atm and 25 [° C.].

<Configuration and operation of oxygen concentration determination unit 52>
Next, the configuration and operation of the oxygen concentration determination unit 52 will be described in detail. The oxygen concentration determination unit 52 includes an in-manifold oxygen concentration determination value calculation unit 70 and an in-manifold oxygen concentration determination unit 71. In the manifold oxygen concentration determination value calculation unit 70, as information indicating the operating state of the internal combustion engine 1, the rotational speed Ne of the internal combustion engine 1 detected based on the output signal of the crank angle sensor 20 and the intake air pressure sensor 2. The intake air pressure Pa detected based on the output signal, the manifold pressure Pb detected based on the output signal of the manifold pressure sensor 8, and the intake air temperature Ta detected based on the output signal of the intake air temperature sensor 4 The intake air humidity Ha detected based on the output signal of the intake air humidity sensor 5 is input from the operating state detection unit 51. The in-manifold oxygen concentration determination value calculation unit 70 calculates an in-manifold oxygen concentration determination value X1 based on the input information indicating the operating state, and uses the calculated in-manifold oxygen concentration determination value X1. Input to the determination unit 71.

  The manifold oxygen concentration determination unit 71 is based on the manifold oxygen concentration determination value X1 input from the manifold oxygen concentration determination value calculation unit 70 and the manifold oxygen concentration Rox_in input from the operation state detection unit 51. It is determined whether or not the PCV valve 30 has a closed failure, and the determination result is input to the determination result logic operation unit 74 as the closed failure determination result D1.

  FIG. 4 is an explanatory diagram showing the oxygen concentration of the gas in the intake manifold for explaining the control device for the internal combustion engine and the control method for the internal combustion engine according to Embodiment 1 of the present invention, and is an external EGR cut This is a graph of the oxygen concentration measurement results in the manifold when the engine load is changed by the opening degree of the throttle valve 6 while the engine speed is constant with the EGR valve 22 fully closed. .

  In FIG. 4, BV31 shows the result of measurement with the PCV valve 30 operating in the open state, and the result of measurement with the blowby gas passage 29 closed, that is, with the BV31 closed. ing. The vertical axis of the graph represents the oxygen concentration in the intake manifold (manifold oxygen concentration), and the horizontal axis represents the differential pressure (Pa-Pb) between the intake air pressure Pa and the manifold pressure Pb. A solid line Y1 indicates a characteristic when the PCV valve 30 is in a normal operation state, and a dotted line Y2 indicates a characteristic when the blow-by gas passage 29 is in a closed state. As apparent from FIG. 4, the larger the differential pressure between the intake air pressure Pa and the manifold pressure Pb, the lower the manifold pressure Pb and the lower the engine load. From the graph shown in FIG. 4, it can be seen that even in the operation state with EGR cut, the oxygen concentration in the manifold decreases by about 0.5 [vol%] as the engine load decreases due to the influence of blow-by gas.

  The flow rate of the blow-by gas is also affected by the manufacturing variation of the PCV valve 30, and even in the same operation state, the amount of blow-by gas sucked into the intake manifold 12 varies depending on the manufacturing variation of the PCV valve 30. As a result, the influence of the blow-by gas on the oxygen concentration also varies. The range between the two broken lines A1 and A2 shown in FIG. 4 shows the influence range due to the manufacturing variation of the PCV valve 30. If the oxygen concentration is higher than the upper broken line A1, the PCV valve 30 is closed. It can be considered that a malfunction has occurred. This characteristic is measured in advance and, for example, set in advance as a map with the rotation speed Ne of the internal combustion engine 1 and the differential pressure [Pa−Pb] between the intake air pressure Pa and the manifold pressure Pb as axes. Thus, failure determination values in various operating states can be calculated.

  FIG. 4 shows the measurement result in a state where the EGR is cut. Since the oxygen concentration in the intake manifold 12 is greatly affected by the introduction of EGR, the failure of the PCV valve 30 due to the oxygen concentration in the intake manifold 12 is shown. When the determination is made, it is necessary to set the EGR in a cut state or a fuel cut state in order to exclude the influence of the EGR gas. Note that when performing a failure determination of the PCV valve 30 according to the fuel cut state, the conditions are different from those during the fuel injection operation. Therefore, the oxygen concentration characteristics in the manifold during the fuel cut operation are measured, and the fuel cut operation is performed. It is possible to accurately determine the failure of the PCV valve by storing it as the determination value.

  In general, the oxygen concentration in the air is said to be 21 [%]. However, since the atmosphere includes humidity, the oxygen concentration in the intake manifold is also affected by environmental conditions such as season and weather. If the standard temperature and humidity conditions are 20 [° C.] and 50 [% RH (RH: Reactive Humidity)], the ratio of water vapor contained in the atmosphere is about 1.2 [%]. If it is 35 [° C.] and 80 [% RH], the water vapor ratio in the atmosphere increases to about 4.4 [%], and the oxygen ratio in the air decreases to about 20.1 [%]. . The failure determination value of the PCV valve can be accurately determined by correcting the failure determination value based on the atmospheric humidity.

  As described above, in order to accurately determine the failure on the closed side of the PCV valve 30 from the oxygen concentration in the manifold, it is necessary to be in the EGR cut state or the fuel cut state and the engine operating load is also low. When all of these conditions are satisfied and the time necessary for the gas state in the intake manifold 12 to stabilize has elapsed, the PCV valve closing side failure determination possible condition is satisfied. The PCV valve closing side failure determination The state where the possible condition is satisfied is also determined by the operation state detection unit 51, and the determination result is output.

  The in-manifold oxygen concentration determination value calculation unit 70 calculates a determination value according to the operating state of the internal combustion engine 1 from the map setting value, and calculates a result of correction according to the atmospheric humidity as an in-manifold oxygen concentration determination value X1. To do.

  The manifold oxygen concentration determination unit 71 detects the detection value of the oxygen concentration determination value X1 in the manifold and the oxygen concentration Rox_in in the manifold if the PCV valve closed side failure determination possible condition output from the operation state detection unit 51 is satisfied. When the value of the oxygen concentration Rox_in in the manifold is higher than the oxygen concentration determination value X1 in the manifold, it is determined that the PCV valve 30 is in the closed side failure due to the oxygen concentration value, and the oxygen concentration value Is output as a closed-side failure determination result D1.

<Configuration / Operation of Oxygen Concentration Change Determination Unit 53>
Next, the configuration and operation of the oxygen concentration change amount determination unit 53 will be described in detail. The oxygen concentration change amount determination unit 53 includes an in-manifold oxygen concentration change amount determination value calculation unit 72 and an in-manifold oxygen concentration change amount determination unit 73. The in-manifold oxygen concentration change amount determination value calculation unit 72 uses the rotational speed Ne of the internal combustion engine 1 detected based on the output signal of the crank angle sensor 20 as information indicating the operating state of the internal combustion engine 1 and the intake air pressure sensor 2. The intake air pressure Pa detected based on the output signal and the manifold pressure Pb detected based on the output signal of the manifold pressure sensor 8 are input from the operation state detection unit 51. The in-manifold oxygen concentration change amount determination value calculation unit 72 calculates the in-manifold oxygen concentration change amount determination value X2 based on the input information indicating the operation state, and the calculated in-manifold oxygen concentration change amount determination value. X2 is input to the oxygen concentration change amount determination unit 73 in the manifold.

  The in-manifold oxygen concentration change amount determination unit 73 and the in-manifold oxygen concentration change amount determination value calculation unit 72 and the in-manifold oxygen concentration change amount determination value X2 input from the operating state detection unit 51 Based on the detected value of Rox_in, it is determined whether or not the PCV valve 30 is closed due to the oxygen concentration change state in the manifold when the BV 31 is opened and closed, and the determination result is determined as the closed-side failure determination result D2. The result is input to the result logic operation unit 74.

  As shown in FIG. 4 described above, if the PCV valve 30 is in a normal state, the oxygen concentration value in the intake manifold 12 changes depending on the open / close state of the blow-by gas passage 29. Since the BV 31 for opening and closing the blow-by gas passage 29 is provided, the deviation between the oxygen concentration in the manifold when the BV 31 is opened and the oxygen concentration in the manifold when the V 31 is closed, that is, the opening and closing of the BV 31 The failure determination on the closed side of the PCV valve 30 can be made based on the change state of the oxygen concentration in the manifold due to the operation.

  The in-manifold oxygen concentration change amount determination value calculation unit 72 measures in advance the characteristics of the change amount of the in-manifold oxygen concentration due to opening and closing of the blow-by passage as shown on the vertical axis of FIG. It is preset as a map centered on the differential pressure (Pa-Pb) between Ne, the intake air pressure Pa, and the manifold pressure Pb. The deviation between the upper limit value indicated by the broken line A1 in the PCV valve manufacturing variation range in FIG. 4 and the detected value of the in-manifold oxygen concentration Rox_in when the blow-by gas passage 29 is closed is the in-manifold oxygen concentration generated by opening and closing of the BV 31. The minimum change amount of Rox_in is considered, and a value further reduced in consideration of manufacturing variations of the PCV valve 30 is set as the oxygen concentration change amount determination value X2 in the manifold.

  Like the oxygen concentration determination value X1 in the above-described manifold oxygen concentration determination value calculation unit 70, the oxygen concentration change amount during the fuel cut operation is set as a separate map so that the failure determination is performed more accurately. Is possible. The in-manifold oxygen concentration change amount determination value calculation unit 72 outputs the minimum change amount of the in-manifold oxygen concentration Rox_in when the BV 31 is opened and closed in the operating state as the in-manifold oxygen concentration change amount X2.

  The in-manifold oxygen concentration change amount determination unit 73 obtains the detection value of the in-manifold oxygen concentration Rox_in after the determination in the oxygen concentration determination unit 52, then closes the BV 31 and acquires the detection value of the in-manifold oxygen concentration Rox_in again. A change amount of the in-manifold oxygen concentration Rox_in is calculated, and based on the change amount, a determination result as to whether or not the PCV valve 30 has a closed side failure due to the oxygen concentration value is output.

  That is, the state in which the PCV valve closed side failure determination possible condition output from the operation state detection unit 51 is satisfied is continued, and the oxygen concentration change amount in the manifold output from the manifold oxygen concentration change amount determination value calculation unit 72 is maintained. The determination value X2 is compared with the detected value of the in-manifold oxygen concentration Rox_in, and if the change amount of the in-manifold oxygen concentration Rox_in is smaller than the in-manifold oxygen concentration change amount determination value X2, the PCV valve 30 is oxygenated. As a determination that the closed side failure is caused by the concentration change amount, a closed side failure determination result D2 based on the oxygen concentration change amount is output.

<Configuration / Operation of PCV Valve Close Failure Determination Unit 54>
Next, the configuration and operation of the PCV valve closing failure determination unit 54 will be described in detail. The PCV valve closing failure determination unit 54 determines the closing side failure determination based on the closed side failure determination result D1 based on the oxygen concentration value output from the oxygen concentration determination unit 52 and the oxygen concentration change amount output from the oxygen concentration change amount determination unit 53. The result D2 is input, and the PCV closed failure determination result D3 is output.

  The determination result logic operation unit 74 includes a closed side failure determination result D1 based on the oxygen concentration value output from the oxygen concentration determination unit 52 and a closed side failure determination result based on the oxygen concentration change amount output from the oxygen concentration change amount determination unit 53. The logical product of D2 is calculated, and when both the closed side failure determination result D1 and the closed side failure determination result D2 are determined to be PCV closed side failures, it is determined to be a PCV closed side failure and PCV The closed failure determination result D3 is output.

  In the case of a system configuration in which the BV 31 is not provided, it is determined as a PCV closed failure only by the output result of the oxygen concentration determination unit 52.

  FIG. 5 is a flowchart for illustrating the control device for the internal combustion engine and the control method for the internal combustion engine according to the first embodiment of the present invention. The processing of the flowchart shown in FIG. 5 is repeatedly executed, for example, at regular intervals, by the arithmetic processing device 90 in the control device 50 executing the software (program) stored in the storage devices 911 and 912.

  In FIG. 5, in step S <b> 01, as described above, the operation state detection unit 51 executes an operation state detection process (operation state detection step) for detecting the operation state of the internal combustion engine 1. The operation state detection unit 51 detects the oxygen concentration Rox_in in the manifold and the like, and also determines whether the PCV valve closing side failure determination possible condition is satisfied.

  Next, in step S02, the process of the in-manifold oxygen concentration determination value calculation unit 70 is executed.

  Next, in step S03, the processing of the above-described in-manifold oxygen concentration determination unit 71 is executed.

  Next, in step S04, the process of the above-described in-manifold oxygen concentration change amount determination value calculation unit 72 is executed.

  Next, in step S05, the above-described process of the in-manifold oxygen concentration change amount determination unit 73 is executed.

Next, in step S06, the processing of the determination result logic operation unit 74 described above is executed.
In the case of a system configuration in which the BV 31 is not provided, the output result of step S03 is input to this step S06 as indicated by a broken line in FIG.

  The present invention includes a throttle valve that opens and closes an intake system, an operating state detection unit that detects an oxygen concentration in an intake manifold that detects an oxygen concentration of the gas in the intake system downstream of the throttle valve, and a crankcase of an engine The present invention can be suitably used in a control device for an internal combustion engine and a control method therefor, including a PCV valve that adjusts the flow rate of blow-by gas flowing through a blow-by gas passage connected to an intake system.

  The present invention is not limited to the internal combustion engine control device and the internal combustion engine control method according to the above-described first and second embodiments, and is within the scope of the present invention without departing from the spirit of the present invention. It is possible to add a part of the configuration or to omit a part of the configuration.

1 internal combustion engine, 2 intake air pressure sensor, 3 air flow sensor, 4 intake air temperature sensor, 5 intake air humidity sensor, 6 throttle valve, 7 throttle opening sensor, 8 manifold pressure sensor, 9 manifold temperature sensor, 10 oxygen concentration in manifold Sensor, 11 Surge tank, 12 Intake manifold, 13 Injector, 14 Intake variable valve timing mechanism, 15 Exhaust variable valve timing mechanism, 16 Ignition coil, 17 Exhaust passage, 18 Air-fuel ratio sensor, 19 Catalyst, 20 Crank angle sensor, 21 EGR Passage, 22 EGR valve, 23 Intake passage, 24 Air cleaner, 25 Cylinder, 26 Crankcase, 27 Head cover, 28 Fresh air introduction passage, 29 Blow-by gas passage, 30 PCV valve, 31 BV, 50 Control device 51, operation state detection unit, 52 oxygen concentration determination unit, 53 oxygen concentration change amount determination unit, 54 PCV valve closing failure determination unit, 70 manifold oxygen concentration determination value calculation unit, 71 manifold oxygen concentration determination unit, 72 manifold Internal oxygen concentration change amount determination value calculation unit, 73 Manifold oxygen concentration change amount determination unit, 74 Determination result logic operation unit, 90 arithmetic processing device, 911, 912 storage device, 92 input circuit, 93 output circuit, 94 communication circuit, 80 air conditioner control device, 81 transmission control device, 100 crankshaft, 110 gas passage, 161 spark plug

Claims (6)

A blow-by gas passage through which the blow-by gas inside the crankcase of the internal combustion engine flows to the downstream side of the throttle valve in the intake system of the internal combustion engine;
A PCV valve that is provided in the blow-by gas passage and opens and closes depending on the pressure inside the crankcase;
Have
A control device for an internal combustion engine configured to control a flow of the blow-by gas based on an opening / closing operation of the PCV valve;
A valve device arranged in series with the PCV valve in the blow-by gas passage and capable of opening and closing the blow-by gas passage;
An operating state detection unit that detects an oxygen concentration of a gas downstream of a connection portion with the blow-by gas passage in the intake system;
The value of the oxygen concentration during operation of the internal combustion engine detected by the operating state detection unit, and the amount of change in the oxygen concentration that occurs when the valve device is opened or closed during operation of the internal combustion engine, , based on, and is configured to determine the presence or absence of abnormality of the PCV valve,
A control device for an internal combustion engine. An EGR passage for recirculating exhaust gas of the internal combustion engine from an exhaust passage of the internal combustion engine to the intake system;
An EGR valve provided in the EGR passage and opening and closing the EGR passage;
With
When determining whether there is an abnormality in the PCV valve, the opening of the EGR valve is changed to reduce the amount of exhaust gas inside the intake system in advance.
The control apparatus for an internal combustion engine according to claim 1 . Only when the operating state detection unit detects that the operating state of the internal combustion engine is operating under a load state lower than a preset value, it is configured to determine whether the PCV valve is abnormal. ing,
The control apparatus for an internal combustion engine according to claim 1 or 2 , characterized in that When the operating state detection unit detects that the internal combustion engine is in an operating state with fuel cut, it is configured to determine whether the PCV valve is abnormal.
The control device for an internal combustion engine according to any one of claims 1 to 3, wherein the control device is an internal combustion engine. An intake air temperature detector for detecting the temperature of intake air in the intake system;
An intake air humidity detector for detecting the humidity of the intake air;
With
The oxygen concentration value is compared with an oxygen concentration determination value to determine whether the PCV valve is abnormal,
The oxygen concentration determination value is corrected based on a water vapor ratio in the intake air calculated based on the detected temperature and humidity of the intake air.
The control device for an internal combustion engine according to any one of claims 1 to 4, wherein the control device is an internal combustion engine. The blow-by gas inside the crankcase of the internal combustion engine is circulated to the downstream side of the throttle valve in the intake system of the internal combustion engine through the blow-by gas passage. A control method for an internal combustion engine that is controlled,
Provided in series with the PCV valve in the blow-by gas passage during operation of the internal combustion engine and the value of the oxygen concentration of the gas downstream of the connection portion of the intake system with the blow-by gas passage Determining whether there is an abnormality in the PCV valve based on the amount of change in the oxygen concentration of the intake system that is caused by opening or closing the valve device
A control method of an internal combustion engine characterized by the above .

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