JP5786468B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a technical field of a control device for an internal combustion engine provided with a supercharger.

  In this type of internal combustion engine, for example, an increase in exhaust gas in the combustion chamber may deteriorate the combustion state. For this reason, for example, Patent Document 1 proposes a technique of performing scavenging by increasing the valve overlap amount of the intake valve and the exhaust valve when the intake pressure in the internal combustion engine is higher than the exhaust pressure. According to this method, the inside of the combustion chamber is scavenged by the scavenging effect, and the increase in exhaust gas in the combustion chamber can be reduced.

  On the other hand, for example, Patent Document 2 proposes a technique for reducing blowback from the combustion chamber to the intake port by increasing the fuel injection pressure as fuel injection control when performing valve overlap.

JP 2009-293516 A JP 2006-037847 A

  When the method of overlapping the intake valve and the exhaust valve is used as in the technique described in Patent Document 1 described above, a situation may arise in which fuel must be injected during the overlap. For example, in a high load and high rotation region of an internal combustion engine, it is required to start fuel injection before the exhaust valve is closed. However, if fuel is injected during the overlap, in addition to the exhaust to be scavenged from the combustion chamber, there is a risk that even the unburned fuel that has just been injected will blow through the exhaust system. In other words, the scavenging effect obtained by increasing the overlap amount causes a technical problem that even the fuel that should remain in the combustion chamber (that is, the fuel that should be combusted in the combustion chamber) is immediately discharged.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a control device for an internal combustion engine that can reduce blow-through of unburned fuel into an exhaust system.

In order to solve the above-described problems, an internal combustion engine control apparatus according to the present invention is a control apparatus for an internal combustion engine that includes a supercharger and fuel injection means for injecting fuel, and detects intake pressure and exhaust pressure in the internal combustion engine. Intake / exhaust pressure detecting means, intake / exhaust valve control means for controlling the valve timing of the intake and exhaust valves provided in the internal combustion engine, the intake pressure is higher than the exhaust pressure, and the intake valve and the exhaust Penetrating force adjusting means for controlling the fuel injection means so as to increase the penetrating force of the fuel injected into the internal combustion engine when the valve timing of the valves overlaps, the fuel injection means, the includes a different second injection means is an internal combustion engine port injection means for injecting fuel into the intake port, and the pressure of fuel to be injected the port injection means, said penetration adjusting hand , As the fuel injected by the port injection means does not interfere with the intake valve, close the injection timing of fuel by the port injection means opening timing of the intake valve and the port injection means and the second The penetration force is increased by changing the injection ratio of the injection means so that the ratio of the lower pressure of the fuel to be injected becomes smaller .

  The internal combustion engine according to the present invention is, for example, an internal combustion engine such as a gasoline engine mounted on a vehicle, and generates a force generated when an air-fuel mixture containing fuel burns in a combustion chamber inside the cylinder, as a piston, a connecting rod and a crank. It can be extracted as a driving force through a physical or mechanical transmission means such as a shaft as appropriate. The internal combustion engine according to the present invention includes a supercharger and fuel injection means.

  The supercharger is, for example, a so-called turbocharger that recovers exhaust heat by a turbine provided in an exhaust passage and drives a compressor, a so-called MAT (Motor Assist Turbo) that drives this turbine by an electric motor or the like, and a turbine housing. VNT (Variable Nozzle Turbo) that changes the supercharging efficiency by opening and closing the nozzle vanes provided, and VGC (Variable Geometry Compressor) that changes the supercharging efficiency by opening and closing the nozzle vanes provided in the compressor housing. ) And the like.

  The fuel injection means includes an injector that injects fuel such as gasoline, light oil, and alcohol fuel used for combustion of the internal combustion engine. The fuel injection means may be, for example, a direct injection type that directly injects fuel into the cylinder of the internal combustion engine, or a port injection type that injects fuel into the intake port.

  A control device for an internal combustion engine according to the present invention is a control device that controls the above-described internal combustion engine. For example, one or a plurality of CPUs (Central Processing Units), MPUs (Micro Processing Units), various processors or various controllers, Alternatively, various processing units such as a single or a plurality of ECUs (Electronic Controlled Units), which may appropriately include various storage means such as ROM (Read Only Memory), RAM (Random Access Memory), buffer memory or flash memory, Various computer systems such as various controllers or microcomputer devices can be used.

  In the control apparatus for an internal combustion engine according to the present invention, the intake pressure and the exhaust pressure in the internal combustion engine are detected by the intake / exhaust pressure detecting means during the operation. The intake / exhaust pressure detection means includes, for example, an intake pressure sensor and an exhaust pressure sensor. However, the intake / exhaust pressure detection means here can detect whether or not the intake pressure is higher than the exhaust pressure, as will be described later, without detecting specific numerical values of the intake pressure and the exhaust pressure. Anything is acceptable.

  Further, according to the control apparatus for an internal combustion engine according to the present invention, the valve timings of the intake valve and the exhaust valve provided in the internal combustion engine are controlled by the intake / exhaust valve control means. The intake / exhaust valve control means adjusts, for example, the opening and closing timings of the intake valves and the opening and closing timings of the exhaust valves as appropriate to advance or retard in accordance with the operating conditions of the internal combustion engine. The intake / exhaust valve control means according to the present invention is particularly capable of overlapping the valve timings of the intake valve and the exhaust valve. That is, it is possible to realize a period in which both the intake valve and the exhaust valve are opened.

  In the present invention, in particular, when the intake / exhaust detection means described above detects that the intake pressure is higher than the exhaust pressure, and the intake / exhaust valve control means overlaps the valve timing of the intake valve and the exhaust valve. The fuel injection means is controlled by the penetration force adjusting means so as to increase the penetration force of the fuel injected into the internal combustion engine. The fuel penetration force is increased by, for example, increasing the pressure of the injected fuel, increasing the injection ratio of the high fuel pressure method when there are multiple injection methods, or reducing the number of fuel split injections. be able to.

  Here, when the intake pressure in the internal combustion engine is higher than the exhaust pressure, if the valve timings of the intake valve and the exhaust valve are overlapped, the inside of the cylinder is scavenged by the scavenging effect, and the deterioration of the combustion state can be prevented. However, when fuel is injected during such an overlap, in addition to the exhaust to be scavenged from the inside of the cylinder, there is a risk that even the unburned fuel that has just been injected will blow through the exhaust system. That is, due to the scavenging effect, even fuel that should remain in the cylinder (that is, fuel that should be combusted inside the cylinder) is immediately discharged.

  However, in the present invention, as described above, when the intake pressure in the internal combustion engine is higher than the exhaust pressure and the valve timings of the intake valve and the exhaust valve are overlapped (hereinafter referred to as “during scavenging” as appropriate). The penetration force of the fuel injected from the fuel injection means is increased. Therefore, it is possible to reduce the unburned fuel that should not be scavenged from being blown out to the exhaust side due to the scavenging effect. The penetrating force of the injected fuel is desirably as high as possible within a range that does not cause inconvenience. However, if the penetrating force at the time of normal fuel injection can be made somewhat higher, the above-described effect can be obtained. Appropriately obtained.

  As described above, according to the control apparatus for an internal combustion engine according to the present invention, it is possible to reduce blow-through of unburned fuel into the exhaust system.

  In one aspect of the control apparatus for an internal combustion engine of the present invention, the penetration force adjusting means increases the penetration force by increasing the pressure of the fuel injected by the fuel injection means.

  According to this aspect, during scavenging, the pressure of the fuel injected from the fuel injection means is increased by the penetration force adjusting means. That is, fuel is injected from the fuel injection means during scavenging at a higher pressure than during normal fuel injection. In this way, since the penetration force of the fuel is increased by the increase in the fuel pressure, it is possible to surely reduce the unburned fuel blow-through into the exhaust system due to the scavenging effect.

  In another aspect of the control device for an internal combustion engine of the present invention, the fuel injection means includes a first injection means and a second injection means with different pressures of fuel to be injected, and the penetration force adjusting means is The penetration force is increased by changing the injection ratio of the first injection means and the second injection means so that the ratio of the lower fuel pressure to be injected becomes smaller.

  According to this aspect, the fuel injection means includes the first injection means and the second injection means that are different in the pressure of the injected fuel. Examples of the first injection unit and the second injection unit include a direct injection type injection unit that directly injects fuel into a cylinder and a port injection type injection unit that injects fuel into an intake port.

  Particularly in this aspect, during scavenging, the penetration force adjusting means changes the injection ratio of the first injection means and the second injection means so that the ratio of the lower fuel pressure to be injected becomes smaller. In other words, the injection ratio is changed so that the ratio of the higher fuel pressure to be injected becomes larger. For example, in the case of the above-described direct injection type injection means and auto injection type injection means, the proportion of the direct injection type injection means in which the pressure of the injected fuel is relatively high is increased, and the pressure of the injected fuel is relatively high. The proportion of low port injection type injection means is reduced.

  If the injection ratio is changed as described above, the pressure of the injected fuel increases as the ratio of the lower fuel pressure is reduced. Therefore, the penetration force of the fuel is increased, and it is possible to reliably reduce the blow-through of the unburned fuel to the exhaust system during scavenging.

  Even when the fuel injection means includes third, fourth,... Injection means in addition to the first injection means and the second injection means, the ratio of the fuel pressure is lower. If the injection ratio is changed so as to decrease, the pressure of the injected fuel as a whole is increased as described above, and the penetration force of the fuel can be increased.

  In another aspect of the control device for an internal combustion engine of the present invention, the internal combustion engine control device includes split injection control means for controlling the fuel injection means so as to divide and inject fuel to be supplied to the internal combustion engine in a plurality of times. The adjusting means increases the penetration force by reducing the number of divisions in the divided injection control means.

  According to this aspect, the fuel injection means is controlled by the divided injection control means so that the fuel to be supplied to the internal combustion engine is divided into a plurality of times and injected. In particular, during scavenging, the split injection control means is controlled by the penetration force adjusting means so as to reduce the number of splits. Thereby, the injection amount per time in the fuel injection means increases. Accordingly, the pressure of the injected fuel is increased, and as a result, the penetration force of the fuel is increased. Therefore, it is possible to reliably reduce the unburned fuel blowing through the exhaust system during scavenging.

  In another aspect of the control apparatus for an internal combustion engine of the present invention, the fuel injection means includes port injection means for injecting fuel into an intake port of the internal combustion engine, and the penetration force adjusting means is the port injection means. The penetrating force is increased by bringing the fuel injection timing according to the above to the opening timing of the intake valve.

  According to this aspect, the fuel injection means can inject fuel from the port injection means for injecting fuel into the intake port. The fuel injection means may include injection means other than the port injection means.

  Particularly in this aspect, during scavenging, the fuel injection timing by the port injection means is brought close to the opening timing of the intake valve by the penetration force adjusting means. Therefore, it can be reduced that the fuel injected from the port injection means interferes with the closed intake valve and the penetration force is weakened. Therefore, the penetration force of fuel can be made higher than usual.

  The fuel injection from the port injection means is normally performed at the closing timing of the intake valve (that is, during a period other than during scavenging). Therefore, if the fuel injection from the port injection means is not performed all at the opening timing of the intake valve, but if it is performed partially overlapping with the opening timing of the intake valve, the above-described effects are correspondingly achieved. can get.

  The effect | action and other gain of this invention are clarified from the form for implementing invention demonstrated below.

It is a schematic diagram showing the whole composition of an engine system. It is a mimetic diagram which illustrates one section composition of an engine. It is a block diagram which shows the structure of ECU. It is a flowchart which shows a scavenge determination process. It is a flowchart which shows the fuel-injection control process in scavenging. It is a graph which shows the correlation with a request | requirement scavenge amount and a fuel injection ratio. It is a graph which shows the correlation with a request | requirement scavenge amount and the fuel injection timing to an intake port. It is a graph which shows the correlation with a request | requirement scavenge amount and the fuel pressure of direct-injection fuel. It is a graph which shows the correlation with a request | requirement scavenge amount and the frequency | count of division | segmentation injection.

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

  First, the configuration of the entire engine system according to the present embodiment will be described with reference to FIG. FIG. 1 is a schematic diagram showing the overall configuration of the engine system. In FIG. 1, for convenience of explanation, among the elements constituting the engine system, only those closely related to the present embodiment are selectively illustrated, and the other elements are omitted as appropriate.

  In FIG. 1, the engine system according to the present embodiment includes an ECU 100, a compressor 110, a turbine 120, and an engine 200.

  The ECU 100 is an example of the “control device for an internal combustion engine” of the present invention, and includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, and controls the entire operation of the engine system. Electronic control unit. The ECU 100 is configured to be able to execute various controls according to a control program stored in, for example, a ROM. A specific configuration of the ECU 100 will be described in detail later.

  The compressor 110 compresses the air that has flowed in and supplies the compressed air downstream. The turbine 120 rotates using exhaust gas supplied from the engine 200 via the exhaust pipe 215 as power. The turbine 110 is connected to the compressor 110 via a shaft, and is configured to be able to rotate integrally with each other. That is, the turbine 120 and the compressor 110 constitute a turbocharger that is an example of a “supercharger” according to the present invention.

  The engine 200 is a gasoline engine that is a power source of a vehicle such as an automobile, and is an example of the “internal combustion engine” according to the present invention. The engine 200 is an in-line four-cylinder gasoline engine in which four cylinders 201 are arranged in series in a cylinder block.

  An air cleaner 101, an intake control valve 103, a compressor 110, an intercooler 113, and a throttle valve 208 are provided on the intake side (that is, the upstream side of the cylinder 201) in the engine 200.

  The air cleaner 101 purifies air sucked from the outside and supplies the air to the compressor 110 via the intake pipe 102. The intercooler 113 provided downstream of the compressor 110 is configured to be able to cool the intake air and increase the supercharging efficiency of the air. A throttle valve 208 is installed downstream of the intercooler 113.

  The air-fuel mixture introduced into the cylinder 201 from the intake side is ignited by an ignition operation by an ignition device (not shown), and an explosion process is performed in the cylinder 201. When the explosion process is performed, the burned air-fuel mixture (including a partially unburned air-fuel mixture) is discharged to an exhaust port (not shown) in the exhaust process following the explosion process. The exhaust discharged to the exhaust port is guided to the exhaust pipe 215.

  An HPLEGR pipe 117, an HPLEGR control valve 118, a turbine 120, a three-way catalyst 122, an LPLEGR pipe 123, and an LPLEGR control valve 124 are provided on the exhaust side of the engine 200 (that is, downstream of the cylinder 201). It has been.

  The HPLEGR pipe 117 can recirculate the exhaust in the exhaust pipe 215 exhausted from the engine 200 to the intake pipe 207 on the intake side of the engine 200. The HPLEGR pipe 117 is provided with an HPLEGR control valve 118 so that the amount of EGR gas can be adjusted. The HPLEGR control valve 118 is an electromagnetic open / close valve that can take, for example, a fully open and fully closed binary open / close state, and is electrically connected to the ECU 100 so that the open / close state is controlled by the ECU 100. ing.

The three-way catalyst 122 is provided on the exhaust pipe 121 and purifies HC (hydrocarbon), CO ₂ (carbon dioxide), and NOx (nitrogen oxide) contained in the exhaust gas that has passed through the turbine 120.

  The LPLEGR pipe 123 can recirculate the exhaust gas downstream of the three-way catalyst 122 to the intake pipe 102 on the inlet side of the compressor 110. The LPLEGR pipe 123 is provided with an LPLEGR control valve 124 so that the amount of EGR gas can be adjusted. Like the HPLEGR control valve 118, the LPLEGR control valve 124 is an electromagnetic on-off valve that can take a binary open / close state, for example, fully open and fully closed. The ECU 100 is configured to be controlled.

  Next, the configuration of the engine 200 according to the present embodiment will be described in more detail with reference to FIG. FIG. 2 is a schematic view illustrating one cross-sectional configuration of the engine. In FIG. 2, the members constituting the engine system shown in FIG. 1 are omitted as appropriate.

  In FIG. 2, an engine 200 burns an air-fuel mixture through an ignition operation by an ignition device 202 in which a part of a spark plug (not shown) is exposed in a combustion chamber in a cylinder 201, and an explosive force due to such combustion. The reciprocating motion of the piston 203 that occurs in response to the above is converted into the rotational motion of the crankshaft 205 via the connecting rod 204.

  In the vicinity of the crankshaft 205, a crank position sensor 206 for detecting the rotational position (ie, crank angle) of the crankshaft 205 is installed. The crank position sensor 206 is electrically connected to the ECU 100, and the ECU 100 determines the angular speed of the crankshaft 205 and the engine speed Ne of the engine 200 based on the crank angle signal output from the crank position sensor 206. This is a calculated configuration.

  In the engine 200, air sucked from the outside passes through the intake pipe 207 and is guided into the cylinder 201 through the intake port 210 when the intake valve 211 is opened. On the other hand, the fuel injection valve of the intake port injector 212a, which is an example of the “port injection unit” according to the present invention, is exposed at the intake port 210, so that fuel can be injected into the intake port 210. ing. The fuel injected from the intake port injector 212 is mixed with the intake air before and after the opening timing of the intake valve 211 to become the above-described mixture. The fuel is stored in a fuel tank (not shown), and is pumped and supplied to the intake port injector 212a through a delivery pipe (not shown) by the action of a feed pump (not shown).

  The communication state between the inside of the cylinder 201 and the intake pipe 207 is controlled by opening and closing the intake valve 210. The air-fuel mixture combusted inside the cylinder 201 becomes exhaust and is guided to the exhaust pipe 215 via the exhaust port 214 when the exhaust valve 213 that opens and closes in conjunction with the opening and closing of the intake valve 210 is opened.

  On the other hand, on the upstream side of the intake port 210 in the intake pipe 207, a throttle valve 208 capable of adjusting the intake air amount is disposed. The throttle valve 208 is configured such that its drive state is controlled by a throttle valve motor 209 electrically connected to the ECU 100.

  The ECU 100 basically controls the throttle valve motor 209 so as to obtain a throttle opening corresponding to the opening of an accelerator pedal (not shown) (that is, the accelerator opening Ta described above). It is also possible to adjust the throttle opening without intervention of the driver's intention through the operation control of 209. That is, the throttle valve 208 is configured as a kind of electronically controlled throttle valve.

  The intake port 210 is provided with an intake pressure sensor 216a that detects intake pressure. On the other hand, the exhaust port 214 is provided with an exhaust pressure sensor 216b for detecting the exhaust pressure. The intake pressure sensor 216a and the exhaust pressure sensor 216b are electrically connected to the ECU 100, respectively, and the detected intake pressure and exhaust pressure are grasped by the ECU 100 at a constant or indefinite detection cycle. Yes.

  An air-fuel ratio sensor 217 configured to be able to detect the exhaust air-fuel ratio of the engine 200 is installed in the exhaust pipe 215. Further, a water temperature sensor 218 for detecting the cooling water temperature related to the cooling water (LLC) circulated and supplied to cool the engine 200 is disposed in the water jacket installed in the cylinder block that houses the cylinder 201. ing. The air-fuel ratio sensor 217 and the water temperature sensor 218 are electrically connected to the ECU 100, and the detected air-fuel ratio and cooling water temperature are grasped by the ECU 100 at a constant or indefinite detection cycle. .

  Here, the engine 200 is provided with a direct injection injector 212b in addition to the intake port injector 212a described above. The direct injection injector 212b has a fuel injection valve in which an injection nozzle is exposed in the combustion chamber, and can be injected as direct injection fuel in a state in which gasoline as fuel is vaporized in a high temperature and high pressure combustion chamber. The direct injection injector 212b is electrically connected to the ECU 100, and the driving state of the direct injection injector 212b is controlled by the ECU 100.

  As a supplement, combustion control using the direct injection fuel from the direct injection injector 212b includes, for example, stratified combustion control under a lean air-fuel ratio, homogeneous combustion control by intake stroke synchronous injection, and the like. The former is a control that makes it possible to make the inside of a cylinder a lean air-fuel ratio by making the spray of direct injection fuel unevenly distributed in the vicinity of the spark plug of the ignition device 202, and the other is, for example, the theory of premixed fuel In this control, combustion is performed under an air-fuel ratio in the vicinity of the air-fuel ratio.

  Next, a specific configuration of the ECU 100 that is the control device for the internal combustion engine according to the present embodiment will be described with reference to FIG. FIG. 3 is a block diagram showing the configuration of the ECU.

  In FIG. 3, the ECU 100 includes an intake / exhaust pressure detection unit 310, a scavenge determination unit 320, a valve timing control unit 330, a penetration force control unit 340, and a fuel injection control unit 350. The penetrating force control unit 340 includes an injection ratio adjusting unit 341, a PFI (Port Fuel Injection) injection timing adjusting unit 342, a DI (Direct Injection) fuel pressure adjusting unit 343, and a DI division number adjusting unit 344. ing.

  The intake / exhaust pressure detection unit 310 is an example of the “intake / exhaust pressure detection means” according to the present invention, and detects the intake pressure and the exhaust pressure in the engine 200 using the intake pressure sensor 216a and the exhaust pressure sensor 216b (see FIG. 2). To do. The values of the intake pressure and the exhaust pressure detected by the intake / exhaust pressure detection unit 310 are transmitted to the scavenge determination unit 320.

  The scavenge determination unit 320 determines whether to perform scavenging in the engine 200 based on the intake pressure and exhaust pressure values detected by the intake / exhaust pressure detection unit 310 and various determination information input from the outside. . Here, scavenging means scavenging inside the cylinder 201 that is realized by overlapping the intake valve 210 and the exhaust valve 213 when the exhaust pressure is higher than the intake pressure. The scavenge determination unit 320 controls the valve timing control unit 330 and the penetration force adjusting unit 340, respectively, depending on whether or not scavenging is performed.

  The valve timing control unit 330 is an example of the “valve timing control means” in the present invention, and is configured to be able to control the valve timings of the intake valve 210 and the exhaust valve 213 (that is, the valve opening timing and the valve closing timing). .

  The penetration force adjusting unit 340 is an example of the “penetration force adjusting means” of the present invention, and is configured to be able to adjust the penetration force of the fuel injected from the port injector 212a and the direct injection injector 212b. The injection division rate adjustment unit 341 adjusts the injection division rate of the port injection injector 212a and the direct injection injector 212b (that is, the ratio of the injection amount of each of the port injection injector 212a and the direct injection injector 212b). The PFI injection timing adjustment unit 342 adjusts the fuel injection timing of the port injector 212a. The DI fuel pressure adjustment unit 343 adjusts the pressure of fuel injected from the direct injection injector 212b. The DI division number adjusting unit 344 adjusts the number of divisions of the divided injection performed by the direct injection injector 212b.

  The fuel injection control unit 350 controls the port injector 212a and the direct injection injector 212b so as to inject fuel under various conditions adjusted by the penetration force adjusting unit 140.

  The ECU 100 configured to include each part described above is an electronic control unit configured integrally, and all the operations related to each part are configured to be executed by the ECU 100. However, the physical, mechanical, and electrical configurations of the above-described parts according to the present invention are not limited thereto. For example, each of these parts includes various ECUs, various processing units, various controllers, microcomputer devices, and the like. It may be configured as a computer system or the like.

  Next, processing performed by the ECU 100 that is the control device for the internal combustion engine according to the present embodiment and effects thereof will be described with reference to FIGS. 4 to 9.

  First, the determination process of whether to perform scavenging performed by the ECU 100 will be described with reference to FIG. FIG. 4 is a flowchart showing the scavenge determination process.

  In FIG. 4, when determining whether to perform scavenging, the ECU 100 first detects the intake pressure and the exhaust pressure of the engine 200 by the intake / exhaust pressure detection unit 310 (step S101). When the intake pressure and the exhaust pressure are detected, the scavenge determination unit 320 determines whether or not the intake pressure is higher than the exhaust pressure (step S102).

  Here, scavenging is to discharge the gas inside the cylinder 201 to the exhaust side by using the scavenging effect obtained by the intake pressure being higher than the exhaust pressure as described above. Therefore, scavenging cannot be performed when the intake pressure is lower than the exhaust pressure. Therefore, when it is determined that the intake pressure is lower than the exhaust pressure (step S102: NO), scavenging is not started and the process ends.

  On the other hand, when it is determined that the intake pressure is higher than the exhaust pressure (step S102: YES), the scavenge determination unit 320 determines whether or not other scavenge start conditions are satisfied (step S103). Other start conditions include, for example, an estimated displacement inside the cylinder 201, an operating state of the engine 200, and the like.

  When the scavenging start condition is not satisfied (step S103: NO), scavenging is not started and the process ends. On the other hand, when the scavenging start condition is satisfied (step S103: YES), the scavenge determination unit 320 determines the required scavenging amount (that is, the amount to be scavenged by scavenging) (step S104). The scavenge determination unit 320 determines the required scavenging amount based on various parameters used when determining whether to perform scavenging, for example.

  When the required scavenging amount is determined, the valve timing control unit 330 is controlled, and the valve timings of the intake valve 210 and the exhaust valve 213 are changed according to the required scavenging amount (step S105). Specifically, the valve overlap period of the intake valve 210 and the exhaust valve 213 is increased as the required scavenging amount increases.

  Next, fuel injection control processing during scavenging performed by the ECU 100 will be described with reference to FIG. FIG. 5 is a flowchart showing the fuel injection control process during scavenging.

  In FIG. 5, when scavenging is started, it is first determined whether or not the engine 200 is in a high rotation and high load state (step S201). When the engine 200 is in a high rotation and high load state, it is considered that the amount of fuel injected into the engine 200 increases. Therefore, whether or not the engine 200 is in the high rotation and high load state can be determined by whether or not the fuel injection amount in the fuel injection control unit 350 exceeds a predetermined threshold value.

  Here, when the engine 200 is in a high rotation and high load state, it is required to inject fuel near the top dead center in order to secure an interval. In this case, if no measures are taken, unburned fuel that has just been injected into the cylinder 201 may blow through to the exhaust side due to the scavenging effect. On the other hand, when engine 200 is not in a high rotation and high load state, it is not required to inject fuel near top dead center. Therefore, it is unlikely that the unburned fuel just injected into the cylinder 201 will blow through to the exhaust side due to the scavenging effect. For this reason, when it is determined that the engine 200 is not in the high rotation and high load state (step S201: NO), the fuel injection control is not performed and the process ends. That is, fuel injection is performed under the same conditions as when scavenging is not performed.

  When the engine 200 is in a high rotation and high load state (step S201: YES), the ECU 100 determines whether or not it is a scavenging region (that is, whether or not the valve timing overlaps and scavenging is actually performed). Is determined (step S202). Here, when it is determined that the region is a scavenging region (step S202: YES), the following fuel injection control process is performed in order to reduce the above-described blowout of unburned fuel to the exhaust side. .

  In the fuel injection control process, it is first determined whether or not fuel is being injected by the intake port injector 212a (step S203). That is, it is determined whether or not fuel injection is not performed only by the direct injection injector 212b. Here, when the fuel injection by the intake port injector 212a is not performed (step S203: NO), the processes related to step S203 and step S204 described below are omitted.

  When fuel injection is performed by the intake port injector 212a (step S203: YES), the injection ratio of the intake port injector 212a and the direct injection injector 212b is changed so that the ratio of the direct injection injector 212b is increased ( Step S204). More specifically, the fuel pressure of the entire fuel injected from the intake port injector 212a and the direct injection injector 212b is increased by increasing the proportion of the direct injection injector 212b that injects fuel at a higher fuel pressure than the intake port injector 212a. Is increased. Thereby, it becomes possible to increase the penetration of fuel.

  Hereinafter, a specific method for changing the injection ratio will be described with reference to FIG. FIG. 6 is a graph showing the correlation between the required scavenging amount and the fuel injection ratio.

  In FIG. 6, the required scavenging amount is indicated as Δovrptsca, and the adjusted ejection ratio in the scavenging is indicated as kpfisca. The injection ratio kpfisca takes a value from “1” to “0”, for example, and when it is “1”, it indicates that all fuel is injected from the intake port injector 212a. Further, “0” indicates that all fuel is injected from the direct injection injector 212b. That is, as the injection ratio kpfisca increases, the proportion of fuel injected from the intake port injector 212a increases.

  Here, if kpfi is given as the reference value of the injection ratio (that is, the value when fuel injection control is not performed), the adjusted injection ratio kpfisca during scavenging is corrected to the reference value kpfi. It is expressed as a value obtained by adding the value Δkpfisca. Δkpfiska is a value corresponding to the shaded portion in the figure, and is calculated using, for example, the following formula (1).

Δkpfisca = Kkpfi × Δovrptsca (1)
Note that Kkpfi is a correction coefficient for the ejection ratio and is a value set in advance.

  As described above, the ejection division rate kpfisca is determined by adding the correction amount corresponding to the requested scavenging amount Δovrptsca to the reference value kpfi.

  Returning to FIG. 5, in the fuel injection control process, the fuel injection timing by the intake port injector 212a is further adjusted (step S205). More specifically, the fuel injection timing by the intake port injector 212a is retarded so as to approach the valve opening timing of the intake valve 210. Therefore, it can be reduced that the fuel injected from the intake port injector 212a interferes with the closed intake valve 210 and the penetration force is weakened.

  Hereinafter, a specific method for changing the fuel injection timing by the intake port injector 212a will be described with reference to FIG. FIG. 7 is a graph showing the correlation between the required scavenging amount and the fuel injection timing to the intake port.

  In FIG. 7, the required scavenging amount is indicated as Δovrptsca, and the fuel injection timing by the adjusted intake port injector 212a during scavenging is indicated as ainjppsca. Here, if ainjp is given as a reference value of the injection timing (that is, a value when fuel injection control is not performed), the adjusted fuel injection timing ainjppsca during scavenging is corrected to the reference value ainjp. It is expressed as a value obtained by adding Δainjppsca. Δainjppsca is a value corresponding to the shaded portion in the figure, and is calculated using, for example, the following formula (2).

Δainjppsca = Kap × Δovrptsca (2)
Kap is a correction coefficient for the injection timing, and is a value set in advance.

  As described above, the fuel injection timing ainjppsca by the intake port injector 212a is determined by adding a correction amount corresponding to the required scavenging amount Δovrptsca to the reference value ainjp.

  Returning to FIG. 5, in the fuel injection control process, the pressure of the fuel by the direct injection injector 212b is further adjusted (step S206). By increasing the pressure of the injected fuel in this way, the penetration force of the fuel can be reliably increased. Note that the intake port injector 212b may be increased in addition to or instead of the fuel pressure of the direct injection injector 212b.

  Hereinafter, a specific method for changing the fuel pressure of the direct injection injector 212b will be described with reference to FIG. FIG. 8 is a graph showing the correlation between the required scavenging amount and the fuel pressure of the direct injection fuel.

  In FIG. 8, the required scavenging amount is indicated as Δovrptsca, and the adjusted fuel pressure in the scavenging is indicated as eprsca. Here, assuming that eprreq is given as a reference value of the fuel pressure (that is, a value when fuel injection control is not performed), the adjusted fuel pressure eprsca during scavenging is a correction value Δeprsca which is a correction value to the reference value eprreq. It is expressed as a value obtained by adding. Δeprsca is a value corresponding to the shaded portion in the figure, and is calculated using, for example, the following formula (3).

Δeprsca = Kp × Δovrptsca (3)
Kp is a fuel pressure correction coefficient and is a preset value.

  As described above, the fuel pressure eprsca by the direct injection injector 212b is determined by adding a correction amount corresponding to the required scavenging amount Δovrptsca to the eprreq that is the reference value.

  Returning to FIG. 5, in the fuel injection control process, the number of divisions of the divided injection by the direct injector 212b is further adjusted (step S207). The direct injection injector 212b is controlled to inject fuel to be supplied to the engine 200 in a plurality of times. Here, if the number of divisions in the divided injection is reduced, the injection amount per one injection in the direct injection injector 212b increases. Accordingly, the pressure of the injected fuel is increased, and as a result, the penetration force of the fuel is increased.

  Hereinafter, a specific method for changing the number of divided injections of the direct injection injector 212b will be described with reference to FIG. FIG. 9 is a graph showing the correlation between the required scavenging amount and the number of divided injections.

  In FIG. 9, the required scavenging amount is shown as Δovrptsca, and the adjusted number of divided injections during scavenging is shown as Nmultisca. Here, if Nmulti is given as the reference value of the divided injection number (that is, the value when fuel injection control is not performed), the adjusted divided injection number Nmultisca during scavenging is corrected to the reference value Nmulti. It is expressed as a value obtained by adding the value ΔNmultisca. ΔNmultisca is a value corresponding to the shaded portion in the figure, and is calculated using, for example, the following formula (4).

ΔNmultisca = Kn × Δovrptsca (4)
Kn is a correction coefficient for the number of divided injections, and is a preset value.

  As described above, the number of divided injections Nmultisca by the direct injector 212b is determined by adding a correction amount corresponding to the required scavenging amount Δovrptsca to Nmulti which is the reference value.

  In the fuel injection control process, various processes for increasing the fuel penetration force as described above are executed. Note that it is not always necessary to perform all of the processes in steps S204 to S207 described above, and an effect can be achieved by performing at least one process.

  As described above, according to the control apparatus for an internal combustion engine according to the present embodiment, the penetration force of the fuel in the scavenge is increased. Therefore, it is possible to reduce the amount of unburned fuel blown into the exhaust system.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification. The control device is also included in the technical scope of the present invention.

  DESCRIPTION OF SYMBOLS 100 ... ECU, 101 ... Air cleaner, 110 ... Compressor, 113 ... Intercooler, 120 ... Turbine, 122 ... Three-way catalyst, reduction cylinder control part, 130 ... Filter selection part, 140 ... Angular velocity detection part, 150 ... Filter processing part, DESCRIPTION OF SYMBOLS 200 ... Engine, 201 ... Cylinder, 205 ... Crankshaft, 206 ... Crank position sensor, 207 ... Intake pipe, 208 ... Throttle valve, 210 ... Intake port 211 ... Intake valve, 212a ... Intake port injector, 212b ... Direct injection injector, 213 ... Exhaust valve, 214 ... Exhaust port, 215 ... Exhaust pipe, 216a ... Intake pressure sensor, 216b ... Exhaust pressure sensor, 310 ... Intake / exhaust pressure detection unit, 320 ... Scavenge determination unit, 330 ... Valve timing control unit, 340 ... Through Force adjustment unit, 341... 42 ... PFI injection timing adjusting section, 343 ... DI fuel pressure adjusting section, 344 ... DI division number adjusting unit, 350 ... fuel injection control unit.

Claims (3)

A control device for an internal combustion engine comprising a supercharger and fuel injection means for injecting fuel,
Intake and exhaust pressure detection means for detecting intake pressure and exhaust pressure in the internal combustion engine;
Intake and exhaust valve control means for controlling the valve timing of the intake and exhaust valves provided in the internal combustion engine;
When the intake pressure is higher than the exhaust pressure and the valve timings of the intake valve and the exhaust valve are overlapped, the fuel injection is performed so that the penetration force of the fuel injected into the internal combustion engine becomes high A penetrating force adjusting means for controlling the means,
The fuel injection means includes a port injection means for injecting fuel into an intake port of the internal combustion engine , and a second injection means in which the pressure of the injected fuel is different from that of the port injection means ,
The penetrating force adjusting means adjusts the penetrating force by bringing the fuel injection timing of the port injection means close to the valve opening timing of the intake valve so that the fuel injected by the port injection means does not interfere with the intake valve. And the penetration force of the port injection means and the second injection means is changed so that the ratio of the lower pressure of the fuel to be injected is reduced to increase the penetration force. A control device for an internal combustion engine.   2. The control apparatus for an internal combustion engine according to claim 1, wherein the penetration force adjusting means increases the penetration force by increasing a pressure of fuel injected by the fuel injection means. A split injection control means for controlling the fuel injection means so as to divide and inject fuel to be supplied to the internal combustion engine a plurality of times;
The control device for an internal combustion engine according to claim 1 or 2 , wherein the penetration force adjusting means increases the penetration force by reducing the number of divisions in the divided injection control means.

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