JP2006258071A - Exhaust emission control method for internal combustion engine and control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for an internal combustion engine capable of suppressing emission of nano particles to the atmosphere. <P>SOLUTION: In the control device for the internal combustion engine provided with an injector 19 capable of supplying fuel into a cylinder 2 of the engine 1 to create particulate matter such as soot of larger diameter than nano particle, an ECU 30 controls operation of the injector 19 to create particulate matter in the cylinder at a time of deceleration or idling operation of the engine 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an exhaust purification method for an internal combustion engine and a control device for the internal combustion engine.

  The carbon-containing suspended fine particles are selectively collected by the first ceramic filter on which the catalyst component is supported, and disposed on the downstream side of the first ceramic filter, and on the second ceramic filter on which the catalyst component is supported. An apparatus for collecting carbon-containing suspended fine particles that have passed through a first ceramic filter is known (see Patent Document 1). Moreover, it is known that the exhaust gas discharged from the internal combustion engine contains nanoparticles (see Non-Patent Document 1). In addition, there are Patent Documents 2 to 4 as prior art documents related to the present invention.

JP 2002-364339 A Japanese Patent Laid-Open No. 10-54268 JP 09-273628 A Japanese Utility Model Publication No. 63-069760 “Car Research”, June 2000, Vol. 22, No. 6, p. 5-10

  Since some of the nanoparticles pass through the ceramic filter, there is a possibility that the nanoparticles are not sufficiently collected in the conventional apparatus. Nanoparticles generally refer to particles having a particle size of 50 nm or less. More specifically, nanoparticles are derived from high-boiling components in fuel and lubricating oil components of internal combustion engines, and the form after the lubricating oil burns, or the aggregated components of the lubricating oil, or the combustion and unburned components There is also the view that it is an aggregate.

  Therefore, an object of the present invention is to provide an exhaust gas purification method for an internal combustion engine and a control device for the internal combustion engine that can suppress discharge of nanoparticles into the atmosphere.

  The exhaust gas purification method for an internal combustion engine of the present invention generates particulate matter having a diameter larger than that of the nanoparticles in the cylinder of the internal combustion engine, and attaches the nanoparticles to the particulate matter to suppress emission of the nanoparticles. Thus, the above-described problem is solved (claim 1).

  According to the exhaust gas purification method for an internal combustion engine of the present invention, nanoparticles can be attached to the particulate matter in the cylinder of the internal combustion engine (hereinafter also referred to as the cylinder), so that the exhaust gas is discharged from the cylinder. The amount of nanoparticles produced can be reduced. That is, by attaching the nanoparticles to a particulate material having a diameter larger than that of the nanoparticles, the amount of nanoparticles ejected with a particle size called a nanoparticle can be reduced. Particulate matter having a diameter larger than that of nanoparticles can be collected by an exhaust purification device such as a ceramic filter. Therefore, by providing such an exhaust purification device downstream of the internal combustion engine, the nanoparticles can be discharged into the atmosphere. Can be suppressed.

  In the present invention, the particulate substance refers to particles having a diameter larger than that of the nanoparticles. Such particulate matter includes, for example, soot and soluble organic matter (SOF).

  The control device for an internal combustion engine of the present invention includes a particulate matter generating means for generating a particulate matter having a diameter larger than the nanoparticles in the cylinder of the internal combustion engine, and the inside of the cylinder during deceleration or idle operation of the internal combustion engine. An operation control means for controlling the operation of the particulate matter generating means so that the particulate matter is generated solves the above-described problem (claim 2).

  According to the control device for an internal combustion engine of the present invention, the particulate matter is generated in the cylinder at the time of deceleration or idle operation of the internal combustion engine, and the nanoparticles generated in the cylinder are adhered to the particulate matter in the cylinder. Therefore, the amount of nanoparticles discharged from the cylinder can be reduced. Therefore, the discharge | release of the nanoparticle to air | atmosphere can be suppressed similarly to the exhaust gas purification method mentioned above.

  The control apparatus for an internal combustion engine of the present invention includes a state determination unit that determines whether or not a nanoparticle component derived from lubricating oil is generated in the cylinder during deceleration or idle operation of the internal combustion engine, and the operation The control means generates the particulate matter so that the particulate matter is generated in the cylinder when the state determination means determines that a nanoparticle component derived from lubricating oil is generated in the cylinder. The means may be operated (Claim 3). When the internal combustion engine is decelerated or idling, the pressure in the cylinder tends to decrease, and therefore, the lubricating oil is easily sucked into the cylinder and burned. Therefore, a nanoparticle component derived from the lubricating oil is easily generated in the cylinder. Therefore, when it is determined by the state determination means that the nanoparticle component derived from the lubricating oil is generated in the cylinder of the internal combustion engine, the particulate matter is generated in the cylinder and the nanoparticle is converted into this particulate matter. By making it adhere, the nanoparticle discharged | emitted from the inside of a cylinder is reduced.

  Lubricating oil penetrates into the cylinder of the internal combustion engine through, for example, a gap between piston rings, and therefore, the lubricating oil is more likely to enter as the pressure in the cylinder is lower. Therefore, in the control device for an internal combustion engine of the present invention, the state determination means determines the deceleration of the internal combustion engine based on a change in the rotational speed of the internal combustion engine when the internal combustion engine is decelerated, and the operation control means The particulate matter generation means may be operated so that the particulate matter is generated in the cylinder more as the deceleration determined by the state determination means is larger. When the deceleration of the internal combustion engine is large, the pressure in the cylinder is more likely to decrease than when the deceleration of the internal combustion engine is small, and therefore the amount of lubricating oil that enters the cylinder may increase. Therefore, when the deceleration of the internal combustion engine is large, the generation amount of the nanoparticle component derived from the lubricating oil may increase as compared with the case where the deceleration is small. Therefore, the production amount of the particulate matter is adjusted according to the deceleration of the internal combustion engine in this way, and the production amount of the particulate matter is appropriately adjusted according to the generation amount of the nanoparticles. Thereby, discharge | release to the atmosphere of a nanoparticle can be suppressed, suppressing the production | generation of an excess particulate matter.

  In the control device for an internal combustion engine of the present invention, the state determination means determines whether the state in the cylinder is a state in which lubricating oil is easily sucked into the cylinder during deceleration or idle operation of the internal combustion engine, When it is determined that the lubricating oil is easily sucked into the cylinder, it may be estimated that many nanoparticle components derived from the lubricating oil are generated in the cylinder. As described above, since some of the nanoparticles are considered to have burned the lubricating oil, the amount of lubricating oil sucked into the cylinder increases when the lubricating oil is easily sucked into the cylinder, It is thought that the amount of lubricating oil that burns increases. Therefore, it can be estimated that many nanoparticle components derived from the lubricating oil are produced.

  The control apparatus for an internal combustion engine of the present invention may be provided with a fuel supply means for supplying fuel into the cylinder as the particulate matter generating means (Claim 6). By supplying fuel into the cylinder and burning the fuel, soot can be generated in the cylinder.

  The control apparatus for an internal combustion engine according to the present invention further includes a lubricating oil combustion amount reducing means for reducing the amount of lubricating oil combusted in the cylinder, and the operation control means is configured to reduce the cylinder during deceleration or idle operation of the internal combustion engine. The operation of the lubricating oil combustion amount reducing means may be controlled so as to reduce the amount of lubricating oil combusted inside. In this case, since the amount of the lubricating oil combusted in the cylinder can be reduced by the lubricating oil combustion amount reducing means, the production amount of the nanoparticle component derived from the lubricating oil can be reduced. Therefore, the amount of nanoparticles generated in the cylinder can be reduced, and the amount of nanoparticles discharged from the cylinder can be further reduced.

  The control device for an internal combustion engine according to the present invention is provided with an exhaust purification catalyst having oxidizing ability in an exhaust passage of the internal combustion engine, and the operation control means controls the exhaust purification catalyst during deceleration or idle operation of the internal combustion engine. When the flow rate of exhaust gas passing through is higher than a predetermined determination flow rate, or when the temperature of the exhaust purification catalyst is lower than a predetermined determination temperature based on the catalyst activation temperature range of the exhaust purification catalyst In at least one of the cases, the particulate matter generating means may be operated so that the particulate matter is generated in the cylinder (claim 8). When the flow rate of exhaust gas passing through the exhaust purification catalyst is large, or when the temperature of the exhaust purification catalyst is low, it is difficult to maintain the exhaust purification performance of the exhaust purification catalyst in a high state. Therefore, in such a case, the particulate matter generating means is operated to reduce the amount of nanoparticles flowing into the exhaust purification catalyst. Thereby, the amount of nanoparticles flowing into the exhaust purification catalyst can be adjusted according to the exhaust purification performance of the exhaust purification catalyst.

  As described above, according to the present invention, the amount of nanoparticles discharged from the cylinder can be reduced by generating a particulate substance in the cylinder and attaching the nanoparticles to the particulate substance. Can do. Therefore, the release of nanoparticles into the atmosphere can be suppressed.

  FIG. 1 shows an embodiment in which the control device of the present invention is applied to a diesel engine 1 as an internal combustion engine. The engine 1 is mounted on a vehicle as a driving power source, and an intake passage 3 and an exhaust passage 4 are connected to the cylinder 2 thereof. The intake passage 3 is provided with a throttle valve 5 for adjusting the amount of intake air, a compressor 6a of the turbocharger 6, and an intercooler 7 for cooling the intake air. The exhaust passage 4 is provided with a turbine 6b of the turbocharger 6, an exhaust throttle valve 8 for restricting the flow of exhaust, and an exhaust purification device 9 for purifying the exhaust. The exhaust purification device 9 includes an NOx storage reduction catalyst 10, a particulate filter 11, and an oxidation catalyst 12 as an exhaust purification catalyst having oxidation ability. Further, the exhaust purification device 9 is provided with a temperature sensor 13 that outputs a signal corresponding to the temperature of the exhaust gas and an A / F sensor 14 that outputs a signal corresponding to the air-fuel ratio of the exhaust gas. The exhaust passage 4 and the intake passage 3 are connected by an EGR passage 15, and an EGR cooler 16 and an EGR valve 17 are provided in the EGR passage 15.

  The engine 1 also includes a fuel supply device 18. The fuel supply device 18 is an injector 19 as fuel supply means for injecting fuel into each cylinder 2, a common rail 20 for storing high-pressure fuel injected from the injector 19, and a fuel supply to the common rail 20 from a fuel tank (not shown). And a fuel pump 21. The fuel supply device 18 also includes a fuel addition injector 22 for supplying fuel to the exhaust passage 4.

  The operations of the exhaust throttle valve 8, the EGR valve 17 and the injectors 19 are controlled by an engine control unit (ECU) 30. The ECU 30 is a known computer unit that is configured as a computer including a microprocessor and peripheral devices such as RAM and ROM necessary for its operation, and controls the operating state of the engine 1. For example, the ECU 30 calculates the amount of fuel to be supplied into the cylinder 2 based on the operating state of the engine 1 and controls the operation of each injector 19 so that the amount of fuel to be supplied is injected into the cylinder 2. Further, the ECU 30 controls the operation of each injector 19 so that the fuel supply into the cylinder 2 is stopped when the engine 1 is decelerated and the rotational speed of the engine 1 is equal to or higher than a predetermined rotational speed. Hereinafter, the ECU 30 stopping the fuel supply into the cylinder 2 when the engine 1 is decelerated is referred to as a fuel cut. In addition, the ECU 30 controls the opening degree of the EGR valve 17 so that an appropriate amount of exhaust gas is recirculated from the exhaust passage 4 to the intake passage 3 according to the operating state of the engine 1. For example, a rotation speed sensor 31 that outputs a signal corresponding to the rotation speed of the engine 1, a temperature sensor 13, and an A / F sensor 14 are connected to the ECU 30 as sensors that are referred to when executing these controls. Although there are various other objects to be controlled by the ECU 30, illustration is omitted here. In addition to the sensors described above, the engine 1 is provided with various sensors, which are not shown.

  When the engine 1 is decelerated or idling, the amount of fuel supplied into the cylinder 2 decreases, so that the pressure in the cylinder 2 decreases and the amount of lubricating oil sucked into the cylinder 2 increases. There is a possibility that a nanoparticle component derived from the lubricating oil is generated in Therefore, the ECU 30 executes the nanoparticle reduction routine of FIG. 2 to reduce the amount of nanoparticles discharged from the cylinder 2 when the engine 1 is decelerated or idling. The routine of FIG. 2 is repeatedly executed at a predetermined cycle while the engine 1 is operating. The ECU 30 functions as operation control means of the present invention by executing the routine of FIG.

  In the nanoparticle reduction routine of FIG. 2, the ECU 30 first determines in step S11 whether or not the operating state of the engine 1 is a deceleration or an idle operation. Whether or not the operating state of the engine 1 is decelerating or idling is determined based on, for example, the rotational speed of the engine 1 and the accelerator opening. The ECU 30 determines that the operating state of the engine 1 is an idle operation when the rotational speed of the engine 1 is within a predetermined idling rotational speed range and the accelerator opening is 0%, that is, the accelerator is not depressed. Further, the ECU 30 determines that the operating state of the engine 1 is a deceleration state when the rotational speed of the engine 1 exceeds a predetermined rotational speed (for example, 1400 rpm) and the accelerator opening is 0%. Further, it may be determined that the engine 1 is decelerating when the amount of change in the rotational speed of the engine 1 is negative, that is, when the rotational speed of the engine 1 is decreasing, or when the amount of change in the torque of the engine 1 is negative. It may be determined that the vehicle is decelerating. Further, it may be determined that the vehicle is decelerating when a brake signal indicating that a brake (not shown) is depressed is on. If it is determined that the engine 1 is not in the deceleration state or the idle operation state, the current routine is terminated.

  On the other hand, when it is determined that the engine 1 is in a deceleration state or an idle operation state, the process proceeds to step S12, and the ECU 30 determines whether or not the temperature of the oxidation catalyst 12 is lower than a predetermined determination temperature. The temperature of the oxidation catalyst 12 may be acquired with reference to, for example, an output signal of the temperature sensor 13, or may be estimated based on the rotation speed or load of the engine 1. The predetermined determination temperature is appropriately set according to the catalyst activation temperature range of the oxidation catalyst 12, and for example, a lower limit value of the catalyst activation temperature range is set. If it is determined that the temperature of the oxidation catalyst 12 is lower than the predetermined determination temperature, step S13 is skipped and the process proceeds to step S14. On the other hand, when it is determined that the temperature of the oxidation catalyst 12 is equal to or higher than the predetermined determination temperature, the process proceeds to step S13, and the ECU 30 determines whether the exhaust gas flow rate is equal to or higher than the predetermined determination flow rate. The exhaust gas flow rate is estimated based on, for example, the rotational speed of the engine 1, the load, and the EGR gas. For example, the exhaust gas flow rate is set such that the exhaust gas flow rate passing through the oxidation catalyst 12 is large and the exhaust gas purification performance of the oxidation catalyst 12 cannot be maintained at a high level. If it is determined that the exhaust gas flow rate is less than the predetermined determination flow rate, the current routine is terminated.

  When it is determined that the exhaust gas flow rate is equal to or higher than the predetermined determination flow rate, the process proceeds to step S14, where the ECU 30 increases the amount of fuel to be supplied into the cylinder 2, and the injector 19 is supplied so that the increased fuel amount is supplied. To control the operation. The amount of fuel to be supplied into the cylinder 2 is set based on the operating state of the engine 1 as described above. Therefore, in this process, first, the fuel supply amount is calculated based on the operating state of the engine 1 at the start of execution of the routine of FIG. 2, and then the calculated fuel supply amount is set as an initial value in a RAM provided in the ECU 30. The amount of fuel to be supplied to the cylinder 2 is increased by storing and adding a predetermined increase to the initial value. The predetermined increase is set such that, for example, when the increased amount of fuel is supplied into the cylinder 2, the torque generated in the engine 1 is maintained at zero or less.

  In the subsequent step S15, the ECU 30 determines whether or not soot as particulate matter is generated in the cylinder 2. Whether or not soot is generated is determined by, for example, combustion of fuel in the cylinder 2, and it is determined that soot is generated when fuel is burned in the cylinder 2. For example, when the fuel cut is performed by the ECU 30, that is, when the fuel supply amount is set to zero, the fuel supply amount into the cylinder 2 is gradually increased and the fuel burns in the cylinder 2. It is determined that soot has been generated. Therefore, for example, the ROM provided in the ECU 30 stores the relationship between the rotational speed of the engine 1 and the minimum value of the fuel supply amount at which the fuel is combusted in the cylinder 2 in advance by experiments or the like, and refers to this map. To determine whether soot has been generated. The soot generation amount has a correlation with the amount of fuel supplied into the cylinder 2 and the injection timing. 3A shows an example of the relationship between the fuel supply amount into the cylinder 2 and the soot generation amount, and FIG. 3B shows the relationship between the fuel injection timing into the cylinder 2 and the soot generation amount. An example is shown respectively. In FIG. 3B, the fuel injection timing is indicated by a crank angle. Therefore, the relationship shown in FIGS. 3A and 3B is stored as a map in the ROM provided in the ECU 30, and the ECU 30 refers to these maps to determine whether soot has been generated or not. Good. In addition, a sensor that outputs a signal corresponding to the amount of soot in the exhaust may be provided in the exhaust passage 4, and it may be determined whether or not soot has been generated in the cylinder 2 with reference to the output signal of this sensor. Examples of such sensors include a laser-induced incandescent sensor (LII, Laser Induced Incense) and a photoacoustic sensor (PAS, Photo Acoustic Spectroscopy).

  When it is determined that no soot is generated in the cylinder 2, the process returns to step S14, and the ECU 30 repeats the processes of steps S14 and S15. On the other hand, if it is determined that soot is generated in the cylinder 2, the process proceeds to step S16, and the ECU 30 returns to the initial value before increasing the fuel injection amount into the cylinder 2. Thereafter, the current routine is terminated.

  As described above, in the routine of FIG. 2, soot is generated in the cylinder 2 when the engine 1 is decelerated. Therefore, the nanoparticles discharged from the cylinder 2 are attached by attaching the nanoparticles in the cylinder 2 to the soot. The amount of can be reduced. Moreover, since the pressure in the cylinder 2 can be increased by burning the fuel in the cylinder 2, the amount of lubricating oil sucked into the cylinder 2 can be reduced. Therefore, the production amount of the nanoparticle component derived from the lubricating oil can be reduced. In the routine of FIG. 2, fuel is injected into the cylinder 2 when the exhaust gas flow rate is equal to or higher than the predetermined determination flow rate, or at least one of the cases where the temperature of the oxidation catalyst 12 is lower than the predetermined determination temperature. The amount of nanoparticles discharged from the cylinder 2 can be reduced while suppressing fuel consumption. Note that the ECU 30 functions as a state determination unit of the present invention by executing the process of step S11 and determining whether or not nanoparticle components derived from the lubricating oil are generated in the cylinder 2. Further, by supplying fuel from the injector 19 into the cylinder 2 and generating soot in the cylinder 2, the injector 19 functions as the particulate matter generating means of the present invention.

  FIG. 4 shows a variation of the nanoparticle reduction routine of FIG. When the amount of lubricating oil sucked into the cylinder 2 increases, the amount of nanoparticle components derived from the lubricating oil increases, and the amount of nanoparticles generated in the cylinder 2 may increase. Thus, the amount of nanoparticles generated in the cylinder 2 has a correlation with the amount of lubricating oil sucked into the cylinder 2, and this amount of lubricating oil has a correlation with the deceleration of the engine 1. have. Therefore, in this modification, the amount of fuel supplied to the cylinder 2 when the engine 1 is decelerated is changed according to the deceleration of the engine 1. In FIG. 4, the same processes as those in FIG. 2 are denoted by the same reference numerals, and the description thereof is omitted.

  In the routine of FIG. 4, the ECU 30 first performs the same processing as in the routine of FIG. 2 up to step S13. In subsequent step S21, the ECU 30 acquires the deceleration of the engine 1 based on the change in the rotational speed of the engine 1 during deceleration. In the next step S <b> 22, the ECU 30 acquires the fuel supply amount supplied into the cylinder 2 based on the acquired deceleration of the engine 1. As the deceleration of the engine 1 is larger, the pressure in the cylinder 2 is more likely to decrease, so that the lubricating oil is easily sucked into the cylinder 2. Therefore, it is estimated that the amount of lubricating oil sucked into the cylinder 2 increases, and the amount of nanoparticle components derived from the lubricating oil increases. Therefore, the ECU 30 refers to the map shown in FIG. 5, for example, and acquires the fuel supply amount corresponding to the deceleration of the engine 1. FIG. 5 shows an example of the relationship between the deceleration of the engine 1 and the amount of fuel supplied to the cylinder 2. Such a relationship is obtained in advance by experiments or the like, and is stored as a map in a ROM provided in the ECU 30. The ECU 30 refers to the map of FIG. 5 and determines that the larger the deceleration of the engine 1 is, the more easily the lubricating oil is sucked into the cylinder 2, and there are more nanoparticle components derived from the lubricating oil in the cylinder 2. Estimate that it has been generated. Therefore, the ECU 30 refers to the map of FIG. 5 and increases the amount of fuel supplied to the cylinder 2 as the deceleration of the engine 1 increases. That is, as the deceleration of the engine 1 is larger, the amount of soot generated in the cylinder 2 is increased.

  In the next step S15, the ECU 30 determines whether or not soot is generated in the cylinder 2. When it is determined that no soot is generated in the cylinder 2, the process returns to step S21, and the ECU 30 repeats the processes of steps S21, S22, and S15. On the other hand, if it is determined that soot has been generated, the process proceeds to step S23 where the ECU 30 sets the fuel supply amount to be supplied to the cylinder 2 based on the rotational speed of the engine 1 and the like. Thereafter, the current routine is terminated.

  In the routine of FIG. 4, since the fuel supply amount to be supplied into the cylinder 2 is set according to the deceleration of the engine 1, the soot generation amount can be adjusted according to the generation amount of nanoparticles. Therefore, excessive generation of soot can be suppressed and the amount of soot discharged from the cylinder 2 can be reduced. In the process of step S22 of FIG. 4, the ECU 30 determines the deceleration of the engine 1 and determines that the lubricating oil is easily sucked into the cylinder 2 when the deceleration is large. Whether or not the lubricating oil is likely to be sucked into the cylinder 2 is determined based on the output signal of the pressure sensor, for example, by providing each cylinder 2 with a signal corresponding to the pressure in the cylinder 2. Good.

  The routine of FIG. 6 shows a lubricating oil combustion amount reduction routine executed by the ECU 30 to reduce the amount of lubricating oil combusted in the cylinder 2. Lubricating oil is more easily sucked as the pressure in the cylinder 2 is lower. Therefore, in this routine, the pressure in the cylinder 2 is increased to reduce the amount of lubricating oil sucked into the cylinder 2. In FIG. 6, the same processes as those in FIG. 2 are denoted by the same reference numerals, and description thereof is omitted. The routine of FIG. 6 is also repeatedly executed at a predetermined cycle while the engine 1 is operating.

  In the routine of FIG. 6, the ECU 30 first performs the same processing as in the routine of FIG. 2 up to step S13. In the subsequent step S31, the ECU 30 controls the opening of the exhaust throttle valve 8 to the closed side. At this time, the exhaust throttle valve 8 is controlled to the closed side by an opening degree so that the operating state of the engine 1 does not change suddenly. In the next step S32, the ECU 30 determines whether or not the pressure in the exhaust passage 4 upstream of the exhaust throttle valve 8 has risen above a predetermined determination pressure. As the predetermined determination pressure, for example, a pressure is set such that the amount of lubricating oil sucked into the cylinder 2 becomes substantially zero. Since the pressure at which the sucked lubricating oil becomes substantially zero changes according to the operating state of the engine 1, for example, the predetermined determination pressure may be changed according to the rotational speed of the engine 1. The pressure of the exhaust passage 4 may be detected by providing a sensor that outputs a signal corresponding to the pressure of the exhaust passage 4, for example, or estimated based on the number of revolutions of the engine 1 and the amount of fuel supplied into the cylinder 2. May be.

  If it is determined that the pressure in the exhaust passage 4 is less than the predetermined determination pressure, the process returns to step S31, and the ECU 30 repeats the processes of steps S31 and S32. On the other hand, if it is determined that the pressure in the exhaust passage 4 is equal to or higher than the predetermined determination pressure, the process proceeds to step S33, where the ECU 30 controls the opening of the exhaust throttle valve 8 to open and closes the opening of the exhaust throttle valve 8. Return to the opening (initial value) before control. Thereafter, the current routine is terminated.

  In the routine of FIG. 6, when the engine 1 is decelerated, the exhaust throttle valve 8 is controlled to the closed side to increase the pressure in the exhaust passage 4 and increase the pressure in the cylinder 2. Thereby, since the quantity of the lubricating oil attracted | sucked in the cylinder 2 can be reduced, the generation amount of the nanoparticle component originating in lubricating oil can be reduced, and the generation amount of a nanoparticle can be reduced. Thus, the exhaust throttle valve 8 functions as the lubricating oil combustion amount reducing means of the present invention by controlling the exhaust throttle valve 8 to the closed side when the engine 1 decelerates and reducing the amount of lubricating oil combusted in the cylinder 2. To do. The method for increasing the pressure in the cylinder 2 is not limited to the above-described method for controlling the opening degree of the exhaust throttle valve 8 to the closed side. For example, the pressure in the intake passage 3 can be increased by opening the EGR valve 17 to connect the intake passage 3 and the exhaust passage 4, so that a decrease in the pressure in the cylinder 2 can be suppressed. For example, at the time of deceleration, at least one of the intake valve and the exhaust valve provided in each cylinder 2 may be maintained in an open state to suppress a decrease in pressure in the cylinder 2. When a variable nozzle is provided in the turbine 6b of the turbocharger 6, the pressure in the exhaust passage 4 may be increased by controlling the variable nozzle to the closed side. In this way, when the pressure drop in the cylinder 2 is suppressed, the EGR valve 17, the intake valve, the exhaust valve, and the variable nozzle each function as the lubricating oil combustion amount reducing means of the present invention.

  The nanoparticle reduction routine shown in FIGS. 2 and 4 and the lubricating oil combustion amount reduction routine shown in FIG. 6 in the present invention may be executed individually, or these routines may be executed in parallel. Good. By executing these routines in parallel, the emission amount of nanoparticles can be reduced while suppressing a decrease in the effectiveness of the engine brake when the engine 1 is decelerated.

  In the embodiment described above, particulate matter such as soot to which nanoparticles are attached is generated in the cylinder 2, but in the present invention, the place for generating and supplying the particulate matter is in the cylinder 2 of the engine 1. It is not limited to. For example, carbon particles may be generated outside the exhaust system of the engine 1 and supplied to the exhaust system of the engine 1.

  The present invention is not limited to the above-described embodiments, and may be implemented in various forms. For example, the internal combustion engine to which the present invention is applied is not limited to a diesel engine, and may be applied to various internal combustion engines using gasoline or other fuels.

  When the engine 1 includes an oil jet device for supplying lubricating oil to the piston, the ECU 30 may stop the operation of the oil jet device when the engine 1 is decelerated. Thus, by stopping the oil jet device when the engine 1 is decelerated, the amount of lubricating oil sucked into the cylinder 2 can be further reduced.

The figure which shows one form which applied the control apparatus of this invention to the diesel engine. The flowchart which shows the nanoparticle reduction routine which ECU performs. FIG. 5 is a diagram illustrating a relationship between a fuel supply parameter into a cylinder and a soot generation amount, in which (a) shows an example of a relationship between a fuel supply amount into the cylinder and a soot generation amount, and (b) An example of the relationship between the fuel injection timing and the amount of generated soot is shown. The flowchart which shows the modification of a nanoparticle reduction routine. The figure which shows an example of the relationship between the deceleration of an engine, and the fuel supply amount in a cylinder. The flowchart which shows the lubricating oil combustion amount reduction routine which ECU performs.

Explanation of symbols

1 Diesel engine (internal combustion engine)
2 cylinder 4 exhaust passage 9 exhaust throttle valve (lubricating oil combustion amount reducing means)
12 Oxidation catalyst (exhaust gas purification catalyst)
17 EGR valve (lubricating oil combustion amount reduction means)
19 Injector (particulate matter generation means, fuel supply means)
30 Engine control unit (operation control means, state determination means)

Claims (8)

  An exhaust gas purification method for an internal combustion engine, wherein particulate matter having a diameter larger than that of nanoparticles is generated in a cylinder of the internal combustion engine, and nanoparticles are attached to the particulate matter to suppress emission of the nanoparticles.   Particulate matter generating means for generating particulate matter having a diameter larger than the nanoparticles in the cylinder of the internal combustion engine, and the particulate matter is generated in the cylinder during deceleration or idle operation of the internal combustion engine And a control device for controlling the operation of the particulate matter generating means. A state determining means for determining whether a nanoparticle component derived from lubricating oil is generated in the cylinder during deceleration or idle operation of the internal combustion engine;
The operation control means is configured so that the particulate matter is generated in the cylinder when the state determination means determines that a nanoparticle component derived from lubricating oil is generated in the cylinder. 3. The control device for an internal combustion engine according to claim 2, wherein the substance generating means is operated. The state determination means determines a deceleration of the internal combustion engine based on a change in the rotational speed of the internal combustion engine during deceleration of the internal combustion engine,
The operation control means operates the particulate matter generating means so that a larger amount of the particulate matter is generated in the cylinder as the deceleration determined by the state determination means is larger. The control device for an internal combustion engine according to claim 3.   The state determination means determines whether or not the state in the cylinder is a state in which the lubricating oil is easily sucked into the cylinder during deceleration or idle operation of the internal combustion engine, and a state in which the lubricating oil is easily sucked into the cylinder 5. The control device for an internal combustion engine according to claim 3, wherein when it is determined that a large amount of nanoparticle components derived from the lubricating oil are generated in the cylinder.   6. The control apparatus for an internal combustion engine according to claim 2, wherein fuel supply means for supplying fuel into the cylinder is provided as the particulate matter generating means. Further comprising a lubricating oil combustion amount reducing means for reducing the amount of lubricating oil combusted in the cylinder,
The operation control means controls the operation of the lubricating oil combustion amount reducing means so that the amount of lubricating oil combusted in the cylinder during deceleration or idle operation of the internal combustion engine is reduced. The control apparatus of the internal combustion engine as described in any one of -6. An exhaust gas purification catalyst having oxidizing ability is provided in the exhaust passage of the internal combustion engine,
When the internal combustion engine is decelerating or idling, the operation control means is configured such that the flow rate of the exhaust gas passing through the exhaust purification catalyst is higher than a predetermined determination flow rate, or the temperature of the exhaust purification catalyst is the exhaust gas The particulate matter generation so that the particulate matter is generated in the cylinder in at least one of cases where the temperature is lower than a preset determination temperature based on the catalytic activation temperature range of the purification catalyst The control device for an internal combustion engine according to any one of claims 2 to 7, wherein the means is operated.

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