JP2010116850A - Device and method for controlling engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a layer of recirculated exhaust gas equivalent to a layer of recirculated exhaust gas of a direct injection engine in a dual injection system engine. <P>SOLUTION: An engine control means (100, 200) control the dual injection system engine provided with a first and a second intake port (14a, 14b) which are mutually independent. The first intake port is constructed to make fluid through the first intake port form a first layer (191) near a spark plug (17), and the second intake port is constructed to make fluid through the second intake port form a second layer (192) around the first layer. The engine control means is provided with a control means (20) controlling a first injector (16a) to supply fuel in an EGR stratified operation zone, and controlling a second injector (16B) so as not to supply fuel while controlling an EGR valve (151) to lead recirculated exhaust gas to the second intake port. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technical field of an engine control apparatus and method for controlling a dual injection engine having an injector for each intake port.

  In this type of apparatus, for example, improvement of fuel consumption, reforming of exhaust gas, and the like are achieved. For example, in Patent Document 1, in an engine in which fuel is directly injected into a cylinder, an air-fuel mixture layer is formed near the spark plug of the engine and an EGR (Exhaust Gas Recirculation) gas layer is formed around the air-fuel mixture. Is formed, and stratified combustion is performed at a stoichiometric air-fuel ratio, thereby improving the fuel efficiency and exhaust purification effect.

  Alternatively, Patent Document 2 includes two intake ports and two exhaust ports connected to the combustion chamber, and the interior of each of the two intake ports is divided into upper and lower flow paths by a partition, An engine is described in which a recirculation port of an exhaust gas recirculation passage is connected to one of the flow paths above and below one of the intake ports. Here, in particular, during low-load operation in the engine hot state, the recirculated exhaust gas is introduced into the upper flow path of the one intake port via the recirculation port, and the upper intake flow path of the other intake port of the two intake ports. A technique for reducing NOx by flowing in intake air is described.

  Alternatively, in Patent Document 3, in an engine in which two intake valves and two exhaust valves are arranged in a combustion chamber and the combustion chamber is divided into two by a partition wall, one of the divided combustion chambers has a stoichiometric air-fuel ratio. In addition, a technique for improving the fuel efficiency and suppressing the emission of nitrogen oxides by supplying an air-fuel mixture and supplying an air-fuel mixture containing exhaust gas to the other split combustion chamber via an EGR pipe is described. ing.

JP 2003-193841 A JP 2003-314339 A JP-A-5-141302

  However, there is a technical problem that it is very difficult to apply the technology described in Patent Document 1 to a dual injection engine having an injector for each intake port. Further, the techniques described in Patent Documents 2 and 3 have a technical problem that it is difficult to form a recirculated exhaust gas layer in a direct injection engine as described in Patent Document 1, for example.

  The present invention has been made in view of the above-mentioned problems, for example, and in an engine of a dual injection system, an engine control device capable of forming a recirculation exhaust gas layer equivalent to a recirculation exhaust gas layer in a direct injection engine And to propose a method.

  In order to solve the above-described problem, an engine control device of the present invention is connected to a combustion chamber and is provided in the first and second intake ports independent of each other and the first intake port, and fuel is supplied to the combustion chamber. A first injector that can be supplied; a second injector that is provided in the second intake port and that can supply the fuel to the combustion chamber; and a recirculation that is connected to the second intake port and led to the second intake port An EGR passage having an EGR valve capable of changing the flow rate of exhaust gas, first and second intake valves provided corresponding to the first and second intake ports, respectively, and an ignition plug provided in the combustion chamber The first intake port is configured such that fluid passing through the first intake port forms a first layer in the combustion chamber in the vicinity of the spark plug, and the second intake port is 2 intake port An engine controller configured to control an engine configured to form a second layer around the first layer in the combustion chamber in the combustion chamber, wherein the fuel is burned in an EGR stratified operation region The first injector is controlled to be supplied to the chamber, and the EGR valve is controlled to guide the reflux exhaust gas to the second intake port, while the fuel is not supplied to the combustion chamber. Control means for controlling the two injectors is provided.

  According to the engine control apparatus of the present invention, the engine control apparatus is connected to the combustion chamber and is provided in the first and second intake ports and the first intake port which are independent from each other. The first injector capable of supplying a large amount of fuel, the second injector provided in the second intake port and capable of supplying fuel to the combustion chamber, and the recirculated exhaust gas connected to the second intake port and led to the second intake port An EGR passage having an EGR valve capable of changing the flow rate of the engine, first and second intake valves provided corresponding to the first and second intake ports, respectively, and an ignition plug provided in the combustion chamber To control. That is, the engine control device controls a dual injection type engine in which an EGR passage is connected to one of the two intake ports.

  In the engine according to the present invention, the first intake port is configured such that a fluid passing through the first intake port forms a first layer in the vicinity of the spark plug in the combustion chamber, and the second intake port is the second intake port. The fluid through the intake port is configured to form a second layer around the first layer in the combustion chamber. Here, “in the vicinity of the spark plug” typically means a range in which flame propagation is possible from when the air-fuel mixture is ignited until the engine exhaust valve is opened.

  Specifically, for example, the first intake port is configured to extend in a direction intersecting with the extending direction of the cylinder bore, and the second intake port is configured to extend in a direction along the extending direction of the cylinder bore of the engine. Yes. Here, the “direction intersecting with the extending direction of the cylinder bore” means a direction in which an angle formed by the extending direction of the cylinder bore and the intersecting direction approaches a right angle.

  The “direction along the direction in which the cylinder bore extends” is not limited to being parallel to the direction in which the cylinder bore extends, and may include a direction shifted by a predetermined angle with respect to the direction in which the cylinder bore extends. In other words, the second intake port may extend in a direction shifted by a predetermined angle with respect to the direction in which the cylinder bore extends as long as it can be considered that the cylinder bore extends along the direction in which the cylinder bore extends.

  The “fluid” according to the present invention typically means intake air (ie, air), air-fuel mixture in which intake air and fuel are mixed, and reflux exhaust gas.

  For example, the control means configured to include a memory, a processor, and the like controls the first injector so as to supply fuel to the combustion chamber and guides the recirculated exhaust gas to the second intake port in the EGR stratified operation region. The second injector is controlled so as not to supply fuel to the combustion chamber while controlling the EGR valve.

  Here, the “EGR stratified operation region” means a region where stratified combustion is performed using the recirculated exhaust gas. Such a region may be set experimentally, empirically, or by simulation, for example, by determining the relationship between the engine speed, engine torque, and the like and fuel consumption, and based on the determined relationship.

  According to the research of the present inventor, in a dual injection type engine, an air-fuel mixture layer is formed on the upper side of the combustion chamber (that is, in the vicinity of the spark plug), and the recirculation is performed on the lower side of the combustion chamber (that is, near the upper surface of the piston). It has been found difficult to form an exhaust gas layer, in other words, to form a reflux exhaust gas layer below the mixture layer in the combustion chamber.

  Specifically, for example, in the technique described in Patent Document 2 described above, the air-fuel mixture introduced from one of the two intake ports to the combustion chamber is supplied to the two exhausts via a part of the upper surface of the piston. The recirculated exhaust gas led from the other intake port of the two intake ports to the combustion chamber flows to the other part of the upper surface of the piston. Therefore, the flow is directed to the other exhaust port of the two exhaust ports. That is, no recirculated exhaust gas layer is formed below the air-fuel mixture layer in the combustion chamber.

  However, in the present invention, the first intake port is configured such that fluid passing through the first intake port forms a first layer in the vicinity of the spark plug in the combustion chamber, and the second intake port is the second intake port. Is configured to form a second layer around the first layer in the combustion chamber. In the EGR stratified operation region, the control means controls the first injector so as to supply the fuel to the combustion chamber, and the EGR valve is controlled so as to guide the recirculated exhaust gas to the second intake port. The second injector is controlled so as not to supply the fuel to the combustion chamber.

  Therefore, for example, when the first intake port is configured to extend in a direction intersecting with the direction in which the cylinder bore extends, and the second intake port is configured to extend in a direction along the direction in which the cylinder bore of the engine extends, the first intake port The air-fuel mixture guided to the combustion chamber through the port becomes a tumble flow that descends along the wall surface of the cylinder bore (that is, toward the upper surface of the piston) through the vicinity of the spark plug. On the other hand, the recirculated exhaust gas guided to the combustion chamber via the second intake port becomes a reverse tumble flow that rises (that is, toward the exhaust port) on the wall surface of the cylinder bore via the upper surface of the piston.

  As a result, the tumble flow of the mixture and the reverse tumble flow of the recirculated exhaust gas collide in the combustion chamber, and a mixture layer as a first layer is formed in the vicinity of the spark plug, and the first layer is formed around the first layer. A layer of reflux exhaust gas as two layers is formed. That is, in the combustion chamber, a reflux exhaust gas layer can be formed below the mixture layer.

  Therefore, according to the engine control apparatus of the present invention, in the dual injection type engine, a recirculation exhaust gas layer equivalent to the recirculation exhaust gas layer in the direct injection engine can be formed.

  As a result, the lower part of the combustion chamber in which the layer of the recirculated exhaust gas is not combusted, and therefore, for example, cooling loss to the wall surface of the piston, cylinder bore, etc. is reduced, and fuel consumption can be improved. In addition, since fuel is supplied only from the first injector (that is, fuel is supplied only to the new air side), unburned hydrocarbons can be reduced. Furthermore, since the recirculated exhaust gas does not contribute to combustion, for example, it is possible to prevent a reduction in combustion speed, misfire, etc., which is very advantageous in practice.

  In one aspect of the engine control apparatus of the present invention, the second intake port extends in a direction along a direction in which the cylinder bore of the engine extends, and the first intake port intersects with a direction in which the second intake port extends. Extending in the direction.

  According to this aspect, the first intake port can be configured relatively easily so that the fluid passing through the first intake port forms a first layer near the spark plug in the combustion chamber, and The second intake port can be configured such that fluid through the second intake port forms a second layer around the first layer in the combustion chamber.

  In another aspect of the engine control apparatus of the present invention, the control means includes a determination unit that determines whether or not the vehicle is in the EGR stratified operation region, on condition that the control unit is determined to be in the EGR stratified operation region. And controlling the first injector to supply the fuel to the combustion chamber and controlling the EGR valve to guide the recirculated exhaust gas to the second intake port while supplying the fuel to the combustion chamber. The second injector is controlled so as not to supply.

  According to this aspect, it can be determined relatively easily whether or not it is the EGR stratification operation region, which is very advantageous in practice.

  For example, the determination means configured to include a memory, a processor, a comparator, and the like is an EGR stratified operation region based on, for example, detecting the engine speed and load, and detecting the engine speed and load. It is determined whether or not.

  The control means controls the first injector so as to supply fuel to the combustion chamber and the EGR valve so as to guide the recirculated exhaust gas to the second intake port when it is determined that it is in the EGR stratified operation region. Meanwhile, the second injector is controlled so as not to supply fuel to the combustion chamber. On the other hand, if it is determined that the control means is not in the EGR stratified operation region, the control means typically controls the EGR valve so as not to guide the recirculated exhaust gas to the second intake port, and supplies the fuel to the combustion chamber. The first and second injectors are controlled.

  In another aspect of the engine control device of the present invention, the engine control device further comprises timing changing means capable of changing the opening and closing timing of each of the first and second intake valves, and the control means further includes the above-mentioned EGR stratified operation region, The timing changing means is controlled so that the second intake valve opens earlier than the first intake valve and closes earlier than the first intake valve.

  According to this aspect, in the engine control device, for example, the timing changing means that is a variable valve timing mechanism can change the opening / closing timing of each of the first and second intake valves. The control means controls the timing changing means so that the second intake valve opens earlier than the first intake valve and closes earlier than the first intake valve in the EGR stratified operation region.

  Here, “the second intake valve opens earlier than the first intake valve and the second intake valve closes earlier than the first intake valve” means that the opening timing of the second intake valve is the first intake valve. It means that the closing timing of the second intake valve is earlier than the closing timing of the first intake valve earlier than the opening timing of the valve. Therefore, if the opening timing of the second intake valve is earlier than the opening timing of the first intake valve and the closing timing of the second intake valve is earlier than the closing timing of the first intake valve, the first intake valve and the second intake valve There may be a period in which both are open. Alternatively, the first intake valve may be opened and closed after the second intake valve is opened and closed.

  By controlling the timing changing means as described above, the recirculated exhaust gas is guided to the combustion chamber before the air-fuel mixture. As a result, the reflux exhaust gas layer can be formed below the air-fuel mixture layer relatively easily, which is very advantageous in practice.

  In order to solve the above problems, an engine control method according to the present invention is provided with first and second intake ports that are connected to a combustion chamber and are independent of each other, and the first intake port, and fuel is supplied to the combustion chamber. A first injector that can be supplied; a second injector that is provided in the second intake port and that can supply the fuel to the combustion chamber; and a recirculation that is connected to the second intake port and led to the second intake port An EGR passage having an EGR valve capable of changing the flow rate of exhaust gas, first and second intake valves provided corresponding to the first and second intake ports, respectively, and an ignition plug provided in the combustion chamber The first intake port is configured such that fluid passing through the first intake port forms a first layer in the combustion chamber in the vicinity of the spark plug, and the second intake port is 2 intake port An engine control method for controlling an engine configured to form a second layer around the first layer in the combustion chamber, wherein the fuel is burned in an EGR stratified operation region The first injector is controlled to be supplied to the chamber, and the EGR valve is controlled to guide the reflux exhaust gas to the second intake port, while the fuel is not supplied to the combustion chamber. A control process for controlling the two injectors is provided.

  According to the engine control method of the present invention, similarly to the engine control device of the present invention described above, in the dual injection type engine, the recirculated exhaust gas layer equivalent to the recirculated exhaust gas layer in the direct injection engine is formed. Can do.

  In the engine control method of the present invention, various aspects of the above-described engine control apparatus of the present invention can be adopted.

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

  Hereinafter, an embodiment according to an engine control device of the present invention will be described with reference to the drawings.

<First Embodiment>
A first embodiment of the engine control apparatus of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a block diagram showing the configuration of the engine control apparatus according to this embodiment, and FIG. 2 is a side view of the engine according to this embodiment. In FIGS. 1 and 2, for convenience of explanation, only members directly related to the present invention are shown, and other members are not shown. The same applies to the subsequent figures.

  1 and 2, the engine 1 includes a cylinder 11, intake valves 12a and 12b, exhaust valves 13a and 13b, intake ports 14a and 14b, EGR passage 15, injectors 16a and 16b, a spark plug 17, and a piston 18. Configured. A combustion chamber 19 is formed in the cylinder 11 by the wall surface of the cylinder 11 and the upper surface of the piston 18.

  The “intake valve 12a”, “intake valve 12b”, “intake port 14a”, “intake port 14b”, “injector 16a”, and “injector 16b” according to the present embodiment are respectively “ It is an example of “1 intake valve”, “second intake valve”, “first intake port”, “second intake port”, “first injector”, and “second injector”.

  An intake control valve 141 is provided in the intake port 14b. Although not shown here, the intake port 14a is also provided with an intake control valve. The EGR passage 15 has one end connected to the intake port 14b and the other end connected to an exhaust port (not shown). The EGR passage 15 is provided with an EGR valve 151 capable of changing the flow rate of the recirculated exhaust gas guided to the intake port 14b, and an EGR surge tank 152 capable of temporarily storing the recirculated exhaust gas.

  Although only one cylinder is shown in FIG. 1, the engine 1 may include a plurality of cylinders.

  The engine control apparatus 100 according to the present embodiment determines whether or not it is in the EGR stratification operation region, and supplies the fuel to the combustion chamber 19 on the condition that it is determined that it is in the EGR stratification operation region. An ECU (Electronic Control Unit) 20 is provided for controlling the injector 16b so as not to supply fuel to the combustion chamber 19 while controlling the EGR valve 151 so as to guide the recirculated exhaust gas to the intake port 14b. It is configured. Here, the “ECU 20” according to the present embodiment is an example of the “control unit” and the “determination unit” according to the present invention. In the present embodiment, a part of the ECU 20 for various electronic controls is used as a part of the engine control apparatus 100.

  The ECU 20 in the engine control device 100 configured as described above first detects, for example, the accelerator opening and the rotation speed of the engine 1 while the vehicle on which the engine control device 100 is mounted is mainly traveling. Based on the detected accelerator opening and the rotational speed of the engine 1, it is determined whether or not it is in the EGR stratified operation region.

  When it is determined that it is in the EGR stratified operation region, the ECU 20 controls the injector 16a so as to supply the fuel to the combustion chamber 19, and controls the EGR valve 151 so as to guide the recirculated exhaust gas to the intake port 14b. The injector 16 b is controlled so as not to supply fuel to the combustion chamber 19.

  Here, as shown in FIG. 2, in this embodiment, the intake port 14 b is particularly configured to extend in a direction along the direction in which the cylinder bore of the engine 1 extends (that is, the vertical direction in FIG. 2). Further, the intake port 14a is configured to extend in a direction intersecting with the direction in which the intake port 14b extends.

  For this reason, the air-fuel mixture containing the fuel injected from the injector 16a becomes a tumble flow that descends along the wall surface of the cylinder 11 through the vicinity of the spark plug 17 as shown by the broken line arrow a in FIG. On the other hand, the recirculated exhaust gas led from the intake port 14b to the combustion chamber 19 becomes a reverse tumble flow that rises on the wall surface of the cylinder 11 via the upper surface of the piston 18 as shown by a broken line arrow b in FIG. As a result, the tumble flow of the air-fuel mixture and the reverse tumble flow of the recirculated exhaust gas collide with each other in the combustion chamber, and the air-fuel mixture stratification 191 that is the stratification of the air-fuel mixture and the EGR stratification 192 that is the stratification of the recirculation exhaust gas are formed. . Note that the “air mixture layer 191” and the “EGR layer 192” according to the present embodiment are examples of the “first layer” and the “second layer” according to the present invention, respectively.

  On the other hand, when it is determined that the region is not in the EGR stratified operation region, the ECU 20 controls the EGR valve 151 so as not to guide the recirculated exhaust gas to the intake port 14b and supplies the fuel to the combustion chamber 19 at the injectors 16a and 16b. To control.

<First Modification>
Next, a first modification of the engine control device according to the present embodiment will be described with reference to FIGS. FIG. 3 is a block diagram showing the configuration of the engine control apparatus according to the first modification of the present embodiment having the same meaning as in FIG. 1, and FIG. 4 is the present embodiment having the same meaning as in FIG. It is a side view of the engine which concerns on a 1st modification of this.

  In the engine 2 according to this modification, the intake port 14a is configured such that the fluid passing through the intake port 14a forms a layer near the spark plug 17 in the combustion chamber 19, and the intake port 14b In the combustion chamber 19, the fluid passing through is formed so as to form a layer around the layer formed in the vicinity of the spark plug 17.

  For this reason, when it is determined that it is in the EGR stratified operation region, the ECU 20 controls the injector 16a so as to supply the fuel to the combustion chamber 19 and also guides the recirculated exhaust gas to the intake port 14b. When the injector 16 b is controlled so that fuel is not supplied to the combustion chamber 19 while 151 is being controlled, the air-fuel mixture flows as shown by the broken line arrow a in FIG. 4, and the air-fuel mixture layer 191 is formed near the spark plug 17. It is formed. On the other hand, as shown by a broken line arrow b in FIG. 4, the reflux exhaust gas flows, and an EGR layer 192 is formed around the formed gas mixture layer 191.

<Second Modification>
Next, a second modification of the engine control apparatus according to this embodiment will be described with reference to FIGS. FIG. 5 is a block diagram showing the configuration of the engine control apparatus according to the second modification of the present embodiment having the same meaning as in FIG. 1, and FIG. 6 is the present embodiment having the same meaning as in FIG. It is a side view of the engine which concerns on a 2nd modification of this.

  In the engine 3 according to this modification, when the intake port 14b is viewed in plan from the side of the spark plug 17 so that the fluid passing through the intake port 14b becomes a swirl flow in the combustion chamber 19, It has a predetermined curvature.

  For this reason, when it is determined that it is in the EGR stratified operation region, the ECU 20 controls the injector 16a so as to supply the fuel to the combustion chamber 19 and also guides the recirculated exhaust gas to the intake port 14b. When the injector 16b is controlled so that fuel is not supplied to the combustion chamber 19 while 151 is controlled, the air-fuel mixture flows as shown by the broken line arrow a in FIGS. A layered layer 191 is formed. On the other hand, the recirculated exhaust gas guided to the combustion chamber 19 via the intake port 14b is spirally moved along the wall surface of the cylinder 11 toward the upper surface of the piston 18 as shown by the broken line arrow b in FIGS. It becomes a swirl style.

  As a result, a mixture layer 191 is formed in the vicinity of the spark plug 17, and an EGR layer 192 is formed around the formed mixture layer 191.

<Second Embodiment>
A second embodiment of the engine control apparatus of the present invention will be described with reference to FIGS. The second embodiment is the same as the first embodiment except that the control performed by the ECU is different due to the provision of the variable valve timing mechanism. Accordingly, the description of the second embodiment that is the same as that of the first embodiment is omitted, and common portions in the drawings are denoted by the same reference numerals, and FIGS. The description will be given with reference.

  In FIG. 7, the engine control apparatus 200 according to the present embodiment can change the opening / closing timings of the temperature sensor 21 that detects the temperature of the cooling water 40 of the engine 4, the intake valves 12a and 12b, and the exhaust valves 13a and 13b. And a variable valve timing mechanism (VVT) 30 as an example of the “timing changing means” according to the present invention. FIG. 7 is a block diagram showing the configuration of the engine control apparatus according to this embodiment.

  When the ECU 20 in the engine control device 200 is determined to be in the EGR stratified operation region, the variable valve timing is set so that the intake valve 12b opens earlier than the intake valve 12a and closes earlier than the intake valve 12a. The mechanism 30 is controlled.

  Specifically, for example, the ECU 20 controls the intake valves 12a and 12b and the exhaust valves 13a and 13b as shown in FIG. FIG. 8 is a conceptual diagram showing the concept of the crank angle of the engine and the opening / closing timings of the intake valve and the exhaust valve according to this embodiment. In FIG. 8, the crank angle at the top dead center (TDC) is 0 degree.

  Next, an engine control process that the ECU 20 in the engine control apparatus 200 configured as described above performs mainly during traveling of a vehicle in which the engine control apparatus 200 is mounted will be described with reference to a flowchart of FIG. To do. This engine control process is mainly executed periodically while the vehicle is running, for example, regularly or irregularly, or continuously every few seconds to several seconds.

  In FIG. 9, first, the ECU 20 acquires the temperature of the cooling water 40 of the engine 4 through the temperature sensor 21 (step S101). Subsequently, the ECU 20 determines whether or not the acquired temperature is higher than 70 degrees Celsius (step S102).

  When it is determined that the acquired temperature is higher than 70 degrees Celsius (step S102: Yes), the ECU 20 detects the depression amount of the accelerator pedal 22, for example, and acquires the accelerator opening (step S103). Subsequently, the ECU 20 determines whether or not the acquired accelerator opening is smaller than 30% (step S104).

  When it is determined that the acquired accelerator opening is smaller than 30% (step S104: Yes), the ECU 20 detects the rotational speed and load of the engine 4 (step S105). Then, ECU20 determines whether it is an EGR stratification operation area | region based on the detected rotation speed and load of the engine 4 (step S106).

  Specifically, the ECU 20 performs the EGR stratification operation region based on the detected rotation speed and load of the engine 4 and a map that prestores the ECU 20 and defines the EGR stratification operation region as shown in FIG. It is determined whether or not there is. More specifically, the ECU 20 determines whether or not the detected state indicated by the rotational speed and load of the engine 4 is within the EGR stratified operation region (within the rounded square in FIG. 10). , It is determined whether or not the EGR stratified operation region.

  FIG. 10 is an example of a map that defines the EGR stratified operation region according to the present embodiment. A solid line T in FIG. 10 indicates the full load torque of the engine 4. In addition, the rounded squares in FIG. 10 indicate equal EGR rate lines. That is, for example, between the equal EGR rate line with the EGR rate of 0% (outermost rounded square in FIG. 10) and the equal EGR rate line with the EGR rate of 10% (second rounded square from the outside in FIG. 10) The EGR rate continuously increases from the equal EGR rate line with an EGR rate of 0% toward the equal EGR rate line with an EGR rate of 10%.

  When it is determined that the region is in the EGR stratified operation region (step S106: Yes), the ECU 20 specifies the EGR rate from the map shown in FIG. 10 based on the detected rotational speed and load of the engine 4 (step S107). ). The ECU 20 further determines the timing for injecting the fuel from the injector 16a based on the detected rotational speed and load of the engine 4 and a map for determining the fuel injection timing as shown in FIG. Identify.

  FIG. 11 is an example of a map for determining the fuel injection timing according to this embodiment. A solid line T in FIG. 11 indicates the full load torque of the engine 4. Further, the dotted rounded squares in FIG. 11 correspond to the equal EGR rate line with the EGR rate of 0% shown in FIG. In FIG. 11, “B270”, “B300”, and “B330” are “Before Top Dead Center (BTDC) 270 degrees”, “300 degrees before top dead center”, and “top dead center”, respectively. “330 degrees before point”.

  In parallel with the processing in step S107, the ECU 20 controls the intake control valve 141 provided in the intake port 14b so that new air is not led to the intake port 14b (step S108). That is, only the recirculated exhaust gas is supplied from the intake port 14 b to the combustion chamber 19.

  Subsequently, the ECU 20 controls the injector 16a so as to inject fuel at the specified fuel injection timing before and after the process of step S107, and also guides the recirculated exhaust gas to the intake port 14b. The injector 16b is controlled so as not to inject fuel while controlling the EGR valve 151 so as to achieve the EGR rate (step S109). Here, the fuel injection time TAU at which the injector 16a injects fuel is twice as long as the fuel injection time when fuel is injected from each of the injectors 16a and 16b.

  In parallel with the process of step S109, the ECU 20 controls the variable valve timing mechanism 30 so that the intake valves 12a and 12b open and close at the timing shown in FIG. 8, for example (step S110).

  Through the processing from step S107 to step S110, the recirculated exhaust gas is guided to the combustion chamber 19 before the air-fuel mixture. As a result, the EGR layer 192 can be formed under the mixed gas layer 191 relatively easily.

  On the other hand, in the process of step S102, when it is determined that the water temperature of the acquired cooling water 40 of the engine 4 is lower than 70 degrees Celsius (step S102: No), the accelerator opening acquired in the process of step S104 is 30. When it is determined that it is greater than% (step S104: No), or when it is determined in the processing of step S106 that it is not the EGR stratified operation region (step S106: No), the ECU 20 sends the recirculated exhaust gas to the intake port 14b. The EGR valve 151 is controlled so as not to guide (step S111).

  Subsequently, the ECU 20 controls the intake control valve 141 so as to guide new air to the intake ports 14a and 14b (step S112). Subsequently, the ECU 20 controls the injectors 16a and 16b so as to inject fuel (step S113). Then, the ECU 20 controls the injectors 16a and 16b so as not to inject fuel when the temperature reaches 400 degrees before the top dead center (step S114).

  In parallel with the processing from step S111 to step S114, the ECU 20 controls the variable valve timing mechanism 30 so that the opening / closing timings of the intake valves 12a and 12b are the same.

  In addition, in step S102 shown in FIG. 9, when the obtained water temperature of the cooling water 40 of the engine 4 is “equal” to 70 degrees Celsius, it may be included in either. Similarly, when the acquired accelerator opening is “equal” to 30% in step S104, it may be included in either of them.

  Note that the present invention is not limited to the above-described embodiment, and can be appropriately changed within a scope not departing from the gist or concept of the invention that can be read from the claims and the entire specification. Control devices and methods are also within the scope of the present invention.

It is a block diagram which shows the structure of the engine control apparatus which concerns on 1st Embodiment. It is a side view of the engine concerning a 1st embodiment. It is a block diagram which shows the structure of the engine control apparatus which concerns on the 1st modification of 1st Embodiment. It is a side view of the engine which concerns on the 1st modification of 1st Embodiment. It is a block diagram which shows the structure of the engine control apparatus which concerns on the 2nd modification of 1st Embodiment. It is a side view of the engine which concerns on the 2nd modification of 1st Embodiment. It is a block diagram which shows the structure of the engine control apparatus which concerns on 2nd Embodiment. It is a conceptual diagram which shows the concept of the opening-closing timing of the crank angle of an engine which concerns on 2nd Embodiment, and an intake valve and an exhaust valve. It is a flowchart which shows the engine control process which ECU which concerns on 2nd Embodiment performs. It is an example of the map which defines the EGR stratification operation area | region which concerns on 2nd Embodiment. It is an example of the map which determines the fuel-injection time which concerns on 2nd Embodiment.

Explanation of symbols

  1, 2, 3, 4 ... engine, 11 ... cylinder, 12a, 12b ... intake valve, 13a, 13b ... exhaust valve, 14a, 14b ... intake port, 15 ... EGR passage, 16a, 16b ... injector, 17 ... spark plug , 18 ... piston, 19 ... combustion chamber, 20 ... ECU, 100, 200 ... engine control device, 141 ... intake control valve, 151 ... EGR valve, 152 ... EGR surge tank, 191 ... mixed gas stratification, 192 ... EGR stratification

Claims (5)

First and second intake ports connected to the combustion chamber and independent of each other, a first injector provided in the first intake port and capable of supplying fuel to the combustion chamber, and provided in the second intake port A second injector capable of supplying the fuel to the combustion chamber; an EGR passage connected to the second intake port and having an EGR valve capable of changing a flow rate of the recirculated exhaust gas guided to the second intake port; A first and a second intake valve provided corresponding to the first and second intake ports, respectively, and a spark plug provided in the combustion chamber, wherein the first intake port is the first intake port; The fluid passing through the second intake port forms a first layer in the combustion chamber in the vicinity of the spark plug, and the second intake port is configured such that the fluid passing through the second intake port passes through the first combustion chamber in the combustion chamber. Around An engine control apparatus for controlling an engine that is configured to form a two-layer,
In the EGR stratified operation region, while controlling the first injector so as to supply the fuel to the combustion chamber, and controlling the EGR valve so as to guide the reflux exhaust gas to the second intake port, An engine control device comprising control means for controlling the second injector so as not to supply the combustion chamber to the combustion chamber. The second intake port extends in a direction along a direction in which a cylinder bore of the engine extends;
The engine control device according to claim 1, wherein the first intake port extends in a direction intersecting with a direction in which the second intake port extends. The control means includes
Determining means for determining whether or not the EGR stratified operation region;
The first injector is controlled to supply the fuel to the combustion chamber on the condition that the EGR stratified operation region is determined, and the recirculated exhaust gas is guided to the second intake port. The engine control apparatus according to claim 1 or 2, wherein the second injector is controlled so as not to supply the fuel to the combustion chamber while controlling the EGR valve. Timing change means capable of changing the opening and closing timing of each of the first and second intake valves;
In the EGR stratified operation region, the control means further opens the second intake valve earlier than the first intake valve, and closes the second intake valve earlier than the first intake valve. The engine control device according to any one of claims 1 to 3, wherein the timing changing unit is controlled. First and second intake ports connected to the combustion chamber and independent of each other, a first injector provided in the first intake port and capable of supplying fuel to the combustion chamber, and provided in the second intake port A second injector capable of supplying the fuel to the combustion chamber; an EGR passage connected to the second intake port and having an EGR valve capable of changing a flow rate of the recirculated exhaust gas guided to the second intake port; A first and a second intake valve provided corresponding to the first and second intake ports, respectively, and a spark plug provided in the combustion chamber, wherein the first intake port is the first intake port; The fluid passing through the second intake port forms a first layer in the combustion chamber in the vicinity of the spark plug, and the second intake port is configured such that the fluid passing through the second intake port passes through the first combustion chamber in the combustion chamber. Around An engine control method for controlling an engine that is configured to form a two-layer,
In the EGR stratified operation region, while controlling the first injector so as to supply the fuel to the combustion chamber, and controlling the EGR valve so as to guide the reflux exhaust gas to the second intake port, An engine control method comprising a control step of controlling the second injector so as not to supply the combustion chamber to the combustion chamber.

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