JP4952732B2 - Internal combustion engine control method and internal combustion engine control system - Google Patents

Description

  The present invention relates to valve closing timing control of an intake valve capable of blocking the inflow of air from an intake passage into a cylinder in an internal combustion engine.

  2. Description of the Related Art Conventionally, for the purpose of improving exhaust gas performance and the like, a method for controlling the opening timing or closing timing of an intake valve of an internal combustion engine according to operating conditions has been developed.

  For example, Patent Document 1 discloses a method for controlling the opening / closing timing of an exhaust valve and an intake valve. In this method, the closing timing of the intake valve is controlled to be retarded from the bottom dead center in the middle load region. On the other hand, in the full load region, the closing timing of the intake valve is advanced from the timing in the medium load region. That is, the cylinder air charge amount is reduced by retarding the intake valve closing timing as the load decreases. As a result, if this method is used, the necessity of air amount control by the throttle valve is reduced, and the pump loss due to the intake pipe pressure drop and thus the cylinder pressure drop during the intake stroke is suppressed, thereby improving the engine operating efficiency. I can do it.

  In the above-described method, the closing timing of the intake valve is retarded in the full load region in a range where the intake air does not blow back as the rotational speed increases. In other words, the intake valve closing timing is retarded as the rotation speed of the intake air is increased, so that high charging efficiency at all rotation speeds is achieved and output is secured.

JP 2002-242709 A

  The method of Patent Document 1 can increase the output while increasing the operating efficiency of the internal combustion engine. However, if the expansion ratio of the internal combustion engine is to be increased in order to further increase the operating efficiency and output, there are the following problems that cannot be dealt with. That is, in order to increase the expansion ratio, it is necessary to increase the geometric compression ratio of the internal combustion engine. When the geometric compression ratio is high, if the cylinder air filling rate is high under the condition that the speed of the internal combustion engine, that is, the rotational speed is low and the gas flow in the cylinder is small, the mixture in the cylinder is overheated during the compression stroke, Unburned mixture may self-ignite before spark ignition, or after ignition, the unburned portion of the in-cylinder mixture may be over-compressed before flame propagation, resulting in excessively high temperature and self-ignition. Will increase.

  In view of such circumstances, an object of the present invention is to improve the operation efficiency and output of an internal combustion engine while avoiding the occurrence of abnormal combustion.

As means for solving the above-mentioned problems, according to one aspect of the present invention, a cylinder that houses a reciprocating piston and forms a combustion chamber, and an intake passage through which air introduced into the cylinder passes, , An intake valve capable of blocking the inflow of air from the intake passage into the cylinder, an exhaust passage through which the exhaust discharged from the cylinder passes, and an outflow of exhaust from the cylinder to the exhaust passage A method for controlling an internal combustion engine with possible exhaust valves is provided. In this method, the closing timing of the intake valve is retarded from the timing at which the amount of air introduced from the intake passage into the cylinder is maximized, and the rotational speed of the internal combustion engine is the same. Below, as the target air charge amount, which is the target value of the air amount introduced into the cylinder, increases, the target air charge amount is maximum and the rotation speed is preset. Control is performed so as to advance as the rotational speed increases under the condition of less than the reference rotational speed .

  According to this method, the closing timing of the intake air in the high-load low-rotation region is sufficiently retarded from the time when the amount of air introduced is maximized, that is, the air blows back from the cylinder to the intake passage side. It is controlled at a time when it occurs sufficiently. As a result, even if the expansion ratio is increased to increase the engine operation efficiency and the possibility that abnormal combustion occurs due to the increase in the compression ratio, in the high load low rotation region where abnormal combustion is likely to occur, The amount of air introduced into the cylinder is suppressed without increasing the pumping loss due to the throttle, the temperature rise in the cylinder during compression is suppressed, and the occurrence of abnormal combustion can be avoided. As a result, according to this method, the engine operation efficiency in the high load and low rotation region can be further increased due to the high expansion ratio and the low pump loss.

  On the other hand, in the region where the rotational speed is higher than the low rotational region, the possibility of abnormal combustion is reduced. Correspondingly, in this method, the valve closing timing of the intake air is controlled to the advance side as the rotational speed increases, and air blowback is suppressed, so that the cylinder air filling amount is increased and the air amount is increased according to the increased air amount. The output is improved by the increased combustion of the fuel. As a result, according to this method, the engine operation efficiency can be increased and the engine output can be improved in a wide range of operation.

  Further, according to another aspect of the present invention, a cylinder that houses a reciprocating piston and that forms a combustion chamber, an intake passage through which air introduced into the cylinder passes, and the intake passage to the inside of the cylinder An internal combustion engine having an intake valve capable of shutting off the inflow of air into the cylinder, an exhaust passage through which exhaust exhausted from the cylinder passes, and an exhaust valve capable of shutting off the outflow of exhaust gas from the cylinder to the exhaust passage A method of controlling an engine, wherein the closing timing of the intake valve is retarded from a timing at which the amount of air flowing into the cylinder from the intake passage becomes maximum, and the rotation of the internal combustion engine Under the condition that the number is the same, the target air filling amount that is the target value of the air amount introduced into the cylinder is controlled to advance as the target air filling amount increases, and the target air filling amount is maximized. The rotation speed is If the engine speed is less than the reference rotation speed set for the above, the valve closing timing of the intake valve is controlled to advance as the rotation speed increases, while the target air filling amount is maximized. When the rotational speed is equal to or higher than the reference rotational speed, a control method for an internal combustion engine is provided, wherein the closing timing of the intake valve is controlled to be retarded according to the increase in the rotational speed. (Claim 2).

  According to this method, the closing timing of the intake air in the high-load low-rotation region is sufficiently retarded from the time when the amount of air introduced is maximized, that is, the air blows back from the cylinder to the intake passage side. It is controlled at a time when it occurs sufficiently. As a result, even if the expansion ratio is increased to increase the engine operation efficiency and the possibility that abnormal combustion occurs due to the increase in the compression ratio, in the high load low rotation region where abnormal combustion is likely to occur, The amount of air introduced into the cylinder is suppressed without increasing pump loss due to the restriction. Thereby, the temperature rise in the cylinder at the time of compression is suppressed, and occurrence of abnormal combustion can be avoided. As a result, according to the present method, the engine operation efficiency in the high load and low rotation region can be further increased due to the high expansion ratio and the low pump loss.

  Furthermore, in this method, in response to the decrease in the possibility of abnormal combustion occurring as the engine speed increases, the intake valve closing timing is reduced in the region where the engine speed is less than the reference engine speed. As the air pressure increases, the air is controlled to be advanced and the air blow-back is suppressed, so that the cylinder air charge amount is increased. On the other hand, in the region where the rotational speed is equal to or higher than the reference rotational speed, the rotational speed corresponds to the retarded intake valve closing timing at which the cylinder air filling amount becomes maximum as the inertia of the intake air flow increases as the engine rotational speed increases. As the number increases, the intake valve closing timing is controlled to the retard side, thereby increasing the cylinder air charge amount. And an output improves by burning the increased fuel according to the increased air amount. As a result, according to the present method, the engine operation efficiency can be improved and the engine output can be improved in a wide range of operation.

  Further, in this method, when the rotational speed is equal to or higher than the reference rotational speed under the condition that the target air filling amount is maximized, the valve opening timing of the exhaust valve is advanced according to the increase in the rotational speed. By controlling in this way, the exhaust resistance can be further reduced as the rotational speed increases, and the engine operating efficiency can be improved (claim 3).

  Further, in this method, when the rotation speed is less than the reference rotation speed under the condition that the target air filling amount is maximized, the opening timing of the intake valve is advanced according to the increase in the rotation speed. At the same time, if the overlap period during which both the intake valve and the exhaust valve are opened by retarding the closing timing of the exhaust valve is increased, the scavenging performance in the cylinder and the inside of the cylinder as the rotational speed increases As a result, the engine output is improved and the engine operating efficiency can be further improved.

  In the present invention, in the operation region where the target air filling amount is equal to or less than a preset reference filling amount, the closing timing of the intake valve may be controlled to a constant value over the entire operation region. 5).

  In this case, pressure control means provided in the intake passage and capable of controlling the pressure in the intake passage is used, and in the operation region where the target air filling amount is equal to or less than the reference filling amount, the target air If the pressure in the intake passage is increased by the pressure control means as the filling amount increases, the air amount in the cylinder can be more reliably filled with the target air while the control range of the intake valve is kept small. It can be a quantity (claim 6).

Further, according to another aspect of the present invention, a cylinder that houses a reciprocating piston and that forms a combustion chamber, an intake passage through which gas introduced into the cylinder passes, and an intake passage from the intake passage to the inside of the cylinder An internal combustion engine having an intake valve capable of shutting off gas flow into the exhaust, an exhaust passage through which exhaust exhausted from the cylinder passes, and an exhaust valve capable of shutting off exhaust flow from the cylinder into the exhaust passage An engine control system comprising: a valve drive mechanism that periodically opens and closes the intake valve and the exhaust valve; and a control unit that controls the valve drive mechanism, wherein the control unit includes the valve drive mechanism, The valve closing timing of the intake valve is controlled to be retarded from the timing at which the amount of air flowing into the cylinder from the intake passage becomes maximum, and the control means controls the valve drive mechanism, The closing timing of the intake valve is The intake valve is closed so that the larger the target air filling amount, which is the target value of the air amount introduced into the cylinder under the condition that the rotational speed of the internal combustion engine is the same, increases. The timing is controlled such that the target air filling amount is maximum and the rotational speed is less than a reference rotational speed set in advance, so that the timing increases as the rotational speed increases. An internal combustion engine control system is provided (claim 7).

  In the control system for the internal combustion engine, the valve closing timing of the intake air in the high load low rotation region is sufficiently retarded from the timing at which the amount of introduced air is maximized by the control of the valve drive mechanism by the control means. That is, it is controlled at a time when air blown back from the cylinder to the intake passage is sufficiently generated. As a result, even if the expansion ratio is increased to increase the engine operation efficiency and the possibility that abnormal combustion occurs due to the increase in the compression ratio, in the high load low rotation region where abnormal combustion is likely to occur, The amount of air introduced into the cylinder is suppressed without increasing pump loss due to the restriction. Therefore, the temperature rise in the cylinder at the time of compression can be suppressed, and the occurrence of abnormal combustion can be avoided. As a result, according to the present control system, the engine operating efficiency in the high load and low rotation region can be further increased due to the high expansion ratio and the low pump loss.

  On the other hand, in the region where the rotational speed is higher than the low rotational region, the possibility of abnormal combustion is reduced. Correspondingly, in this control system, the valve closing timing of the intake air is controlled to the advance side as the rotational speed increases, and air blowback is suppressed, so the cylinder air filling amount is increased and the increased air amount is increased. The output is improved by burning the increased fuel accordingly. As a result, according to the present control system, the engine operation efficiency can be improved and the engine output can be improved in a wide range of operation.

  According to still another aspect of the present invention, a cylinder that houses a reciprocating piston and forms a combustion chamber, an intake passage through which gas introduced into the cylinder passes, and the intake passage into the cylinder An internal combustion engine having an intake valve capable of blocking an inflow of gas, an exhaust passage through which exhaust exhausted from the cylinder passes, and an exhaust valve capable of blocking outflow of exhaust from the cylinder to the exhaust passage A valve drive mechanism for periodically opening and closing the intake valve and the exhaust valve, and a control means for controlling the valve drive mechanism, wherein the control means controls the valve drive mechanism to the intake air. The cylinder is closed under a condition that the valve closing timing is retarded from the timing at which the amount of air flowing into the cylinder from the intake passage becomes maximum and the rotational speed of the internal combustion engine is the same. Of the amount of air introduced into Control is performed so that the target air filling amount, which is a standard value, increases as the target air filling amount increases, and the control means controls the valve drive mechanism so that the target air filling amount is maximum and the rotation speed is preset. Under the condition of less than the reference rotational speed, the closing timing of the intake valve is advanced as the rotational speed increases, the target air filling amount is maximum, and the rotational speed is the reference rotational speed. An internal combustion engine control system is provided that performs control so that the closing timing of the intake valve becomes more retarded as the rotational speed increases under the above conditions (Claim 8).

  In the control system for the internal combustion engine, the valve closing timing of the intake air in the high load low rotation region is sufficiently retarded from the timing at which the amount of introduced air is maximized by the control of the valve drive mechanism by the control means. That is, it is controlled at a time when air blown back from the cylinder to the intake passage is sufficiently generated. As a result, even if the compression ratio increases to increase the engine operation efficiency and the possibility of abnormal combustion increases, the throttle valve in a high-load low-rotation region where there is a high possibility of abnormal combustion. The amount of air introduced into the cylinder is suppressed without increasing the pump loss due to the throttle. Therefore, the temperature rise in the cylinder at the time of compression can be suppressed, and the occurrence of abnormal combustion can be avoided. As a result, the engine operation efficiency in the high load and low rotation region can be further increased by the high expansion ratio and the low pump loss.

  Further, in the present control system, the valve closing timing of the intake air is set to the rotational speed in response to the possibility that the abnormal combustion occurs as the engine speed increases due to the control of the valve drive mechanism by the control means. However, in the region where the rotational speed is less than the reference rotational speed, the rotational speed is controlled to the advance side as the rotational speed is increased, and air blowback is suppressed, so that the cylinder air filling amount is increased. On the other hand, in the region where the rotational speed is equal to or higher than the reference rotational speed, the rotational speed corresponds to the retarded intake valve closing timing at which the cylinder air filling amount becomes maximum as the inertia of the intake air flow increases as the engine rotational speed increases. As the number increases, the intake valve closing timing is controlled to the retard side, so that the cylinder air charge amount is increased. When the air filling amount is increased in this way, the output is improved by burning the fuel increased in accordance with the increased air amount.

  Further, in this control system, when the rotation speed is equal to or higher than the reference rotation speed under the condition that the target air filling amount is maximized, the control means increases the valve opening timing of the exhaust valve. If the valve drive mechanism is controlled so as to advance according to the engine speed, the exhaust resistance can be further reduced as the rotational speed increases, and the engine operating efficiency can be improved.

  Specific configurations of the valve drive mechanism and the like are not particularly limited. For example, the valve drive mechanism is driven by a crankshaft connected to the piston to drive the intake valve and the exhaust valve. A camshaft and a phase variable mechanism that changes a phase of the camshaft with respect to the crankshaft, and the control means drives the phase variable mechanism to change the phase of the camshaft with respect to the crankshaft. And controlling the closing timing of the intake valve (claim 10).

  In the control system of the internal combustion engine, the control means may be configured such that the closing timing of the intake valve is constant over the entire operation region in the operation region where the target air charge amount is equal to or less than a preset reference charge amount. Thus, the valve drive mechanism may be controlled (claim 11).

  Further, the control means drives the phase variable mechanism to change the phase of the camshaft with respect to the crankshaft, so that the rotation speed becomes the reference rotation speed under the condition that the target air filling amount becomes maximum. If the engine speed is less than that, the intake valve opening timing is advanced and the exhaust valve closing timing is retarded to open both the intake valve and the exhaust valve according to the increase in the rotational speed. If the control is performed to increase the overlap period, the scavenging performance in the cylinder and thus the amount of fresh air in the cylinder is increased as the rotational speed is increased, and the engine output is increased to further improve the engine operating efficiency. (Claim 12).

  Here, in a high compression ratio internal combustion engine in which the geometric compression ratio of the cylinder is 13 or more, the temperature in the cylinder tends to increase due to the compression, and abnormal combustion is likely to occur. Therefore, it is effective to apply the control system of the internal combustion engine to such an internal combustion engine having a high compression ratio (claim 13).

  Further, a throttle valve provided in the intake passage and capable of changing an opening area of the intake passage and a throttle drive mechanism for driving the throttle valve are provided, and the throttle valve is configured to be the target air by the control means. It is preferable that the throttle drive mechanism is controlled so as to increase the opening area as the filling amount increases (claim 14).

  In this way, the air amount in the cylinder can be more reliably set to the target air filling amount by the throttle valve while keeping the control range of the closing timing of the intake valve small.

  As described above, according to the present invention, the engine operation efficiency can be increased and the engine output can be improved in a wide range of operation.

1 is a schematic view of an overall structure of an engine system to which an internal combustion engine control method according to the present invention is applied. It is a flowchart for demonstrating the control procedure of the control method which concerns on this invention. It is a figure which shows the opening-and-closing timing of an intake valve with respect to rotation speed and target air filling amount. It is a figure which shows the opening degree of the throttle valve with respect to rotation speed and target air filling amount. (A) It is a figure which shows the valve timing of an intake valve and an exhaust valve in a low load area | region. (B) It is a figure which shows the valve timing of an intake valve and an exhaust valve in a high load low rotation area | region. (C) It is a figure which shows the valve timing of an intake valve and an exhaust valve in a high load rotation area. (D) It is a figure which shows the valve timing of an intake valve and an exhaust valve in a high load high rotation area | region. It is a figure for demonstrating the relationship between the closing timing of an intake valve, and air filling amount. It is a figure for demonstrating the relationship between the closing timing of the intake valve for every rotation speed, and the air filling amount. It is a figure which shows the opening / closing timing of the exhaust valve with respect to rotation speed and target air filling amount.

  A preferred embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 schematically shows the overall structure of an engine system to which the present invention is applied. This engine system includes an engine body (internal combustion engine) 1 and an engine controller (control means) 100 for controlling various actuators attached to the engine body 1.

  The engine body 1 is a four-cycle spark ignition type internal combustion engine mounted on a vehicle such as an automobile, and its output shaft is coupled to drive wheels via a transmission to propel the vehicle. The engine body 1 includes a cylinder block 12 and a cylinder head 13 placed thereon. A plurality of cylinders 11 are formed inside the cylinder block 12 and the cylinder head 13. Although the number of these cylinders 11 is not specifically limited, For example, four cylinders 11 are formed. A crankshaft 14 is rotatably supported on the cylinder block 11 by a journal, a bearing or the like.

  Pistons 15 are slidably fitted in the cylinders 11, and combustion chambers 17 are defined above the pistons 15, respectively.

  Here, in this embodiment, the engine body is the ratio of the volume of the combustion chamber 17 when the piston 15 is located at the top dead center and the volume of the combustion chamber 17 when the piston 15 is located at the bottom dead center. The geometric compression ratio of 1 is set to approximately 14. Of course, the value of this geometric compression ratio is not limited to 14. For example, the geometric compression ratio is preferably higher from the viewpoint of improving the engine efficiency. However, if the geometric compression ratio is increased, the temperature in the cylinder becomes too high in the compression stroke, and the possibility of self-ignition occurring at an unexpected timing increases. Therefore, the geometric compression ratio of the engine body 1 is preferably 13 or more and 16 or less.

  The cylinder head 13 is formed with two intake ports 18 and two exhaust ports 19 communicating with each combustion chamber 17. The cylinder head 13 includes an intake valve (intake valve) 21 for shutting off each intake port 18 from the combustion chamber 17 and an exhaust valve for shutting off each exhaust port 19 from the combustion chamber 17. (Exhaust valve) 22 is provided. The intake valve 21 is driven by an intake valve drive mechanism (valve drive mechanism) 30 described later, thereby opening and closing each intake port 18 at a predetermined timing. On the other hand, the exhaust valve 22 is driven by an exhaust valve drive mechanism (valve drive mechanism) 40 described later, thereby opening and closing each exhaust port 19.

  The intake valve drive mechanism 30 and the exhaust valve drive mechanism 40 have an intake camshaft 31 and an exhaust camshaft 41, respectively. The intake camshaft 31 and the exhaust camshaft 41 are connected to the crankshaft 14 via a power transmission mechanism such as a known chain / sprocket mechanism. The power transmission mechanism is configured such that the camshafts 31 and 41 rotate once while the crankshaft 14 rotates twice.

  The intake valve drive mechanism 30 is provided with an intake camshaft phase variable mechanism (phase variable mechanism) 32 between the power transmission mechanism and the intake camshaft 31. The intake camshaft phase varying mechanism 32 is for changing the valve timing of the intake valve 21, and is arranged coaxially with the intake camshaft 31 and directly driven by the crankshaft 14 and the intake cam. The phase difference between the crankshaft 14 and the intake camshaft 31 is changed by changing the phase difference between the shaft 31 and the shaft 31.

The intake camshaft phase varying mechanism 32 has, for example, a plurality of liquid chambers arranged in the circumferential direction between the driven shaft and the intake camshaft 31, and the pressure difference is provided between the liquid chambers. A hydraulic mechanism that changes the phase difference, or an electromagnetic mechanism that has an electromagnet provided between the driven shaft and the intake camshaft 31, and changes the phase difference by applying electric power to the electromagnet. Etc. The intake camshaft phase varying mechanism 32 changes the phase difference based on the valve timing of the intake valve 21 calculated by the engine controller 100 described later. In this embodiment, the intake camshaft phase varying mechanism 32 changes the phase difference while keeping the valve opening period and the lift amount, that is, the valve profile, of the intake valve 21 constant. The opening timing (valve opening timing) IVO and the closing timing (valve closing timing) IVC are changed. The phase angle of the intake camshaft 31 is detected by the cam phase sensor 39, and the signal θ _{IVC_A} is transmitted to the engine control means 100.

  The exhaust valve drive mechanism 40 is also provided with an exhaust camshaft phase variable mechanism (phase variable mechanism) 42 between the power transmission mechanism and the exhaust camshaft 41. The exhaust camshaft phase varying mechanism 42 is for changing the valve timing of the exhaust valve 22, and its specific structure is the same as that of the intake camshaft phase varying mechanism 32. Then, the opening timing (opening timing) EVO and the closing timing (closing timing) EVC of the exhaust valve 22 are changed while the valve opening period and the lift amount, that is, the valve profile, of the exhaust valve 22 are kept constant. .

The intake port 18 communicates with the surge tank 55 a via the intake manifold 55. A throttle body (throttle drive mechanism) 56 is provided in the intake passage upstream of the surge tank 55a. Inside the throttle body 56, a throttle valve 57 (pressure control means) for adjusting the intake air flow rate from the outside toward the surge tank 55a is pivotally provided. The throttle valve 57 can change the intake flow rate by changing the opening area of the intake passage, that is, the flow passage area, and can change the pressure in the intake passage downstream of the throttle valve. The throttle valve 57 is driven by a throttle actuator 58. The throttle actuator 58 drives the throttle valve 57 so that the opening TVO becomes the target throttle opening TVO _D calculated by the engine controller 100 described later of the throttle valve 57. Here, the intake passage in the claims includes all of the intake port 18, the intake manifold 55, and the surge tank 55a downstream of the throttle valve 57. In the present embodiment, by adjusting the opening degree of the throttle valve 57 and the closing timing of the intake valve 21, the amount of air charged in the cylinder 11, that is, the air filling amount CE in the cylinder 11 is set to an appropriate value. To control.

  The exhaust port 19 communicates with an exhaust pipe via an exhaust manifold 60. An exhaust gas purification system is disposed in the exhaust pipe. The specific configuration of the exhaust gas purification system is not particularly limited, and examples thereof include those having a catalytic converter 61 such as a three-way catalyst, a lean NOx catalyst, and an oxidation catalyst.

The intake manifold 55 and the exhaust manifold 60 are communicated with each other by an EGR pipe 62, and a part of the exhaust gas is circulated to the intake side. The EGR pipe 62 is provided with an EGR valve 63 for adjusting the flow rate of EGR gas that circulates through the EGR pipe 62 to the intake side. The EGR valve 63 is driven by an EGR valve actuator 64. The EGR valve actuator 64 drives the EGR valve 63 so that the opening degree of the EGR valve 63 becomes an EGR opening degree EGR _open calculated by the engine controller 100 described later, thereby reducing the flow rate of the EGR gas. Adjust to an appropriate value.

  A spark plug 51 is attached to the cylinder head 13 so that the tip of the cylinder head 13 faces the combustion chamber 17. The spark plug 51 generates a spark in the combustion chamber 17 when energized by the ignition system 52 based on an ignition timing SA calculated by an engine controller 100 described later.

  In addition, a fuel injection valve 53 for directly injecting fuel into the combustion chamber 17 is attached to the cylinder head 13 so that the tip thereof faces the combustion chamber 17. More specifically, the tip of the fuel injection valve 53 is positioned below the two intake ports 18 in the vertical direction, and is positioned between the two intake ports 18 in the horizontal direction. Has been placed. The fuel injection valve 53 is energized for a predetermined period based on a fuel injection amount FP calculated by an engine controller 100, which will be described later, by a fuel system 54, so that the combustion chamber 17 A predetermined amount of fuel is injected into the inside.

  The engine controller 100 is a controller based on a well-known microcomputer, and performs input / output of various signals, a CPU for executing a program, a memory including a RAM and a ROM for storing the program and data, and the like. And an I / O bus.

The engine controller 100 includes an intake air amount AF detected by an air flow meter 71, an air pressure MAP in the intake manifold 55 detected by an intake pressure sensor 72, and a crank angle sensor 73 via the I / O bus. The crank angle pulse signal detected by the oxygen concentration sensor, the oxygen concentration EGO of the exhaust gas detected by the oxygen concentration sensor 74, the accelerator pedal depression amount α detected by the accelerator opening sensor 75, and the vehicle speed sensor 76 Various information such as the vehicle speed VSP is input. The engine controller 100 calculates command values for various actuators based on the input information so that the air filling amount, ignition timing, and the like in the cylinder 11 become appropriate values according to operating conditions. . For example, command values such as the throttle opening TVO, the fuel injection amount FP, the ignition timing SA, the target value of the intake valve timing, the target value of the exhaust valve timing, the EGR opening EGR _open, etc. are calculated, and these are calculated as the throttle actuator 58. , The fuel system 54, the ignition system 52, the intake camshaft phase variable mechanism 32, the EGR valve actuator 64, and the like.

  A specific calculation procedure in the engine controller 100 will be described with reference to the flowchart of FIG.

  First, various signals such as the accelerator pedal depression amount α are read (step S1).

Next, a target torque TQ _D is calculated based on the accelerator pedal depression amount α, the engine body speed N _ENG calculated from the crank angle pulse signal, and the vehicle speed CSP (step S2). Based on the calculated target torque TQ _D and the rotational speed N _ENG , the fuel injection amount FP, the target air filling amount (target value of the air filling amount CE in the cylinder 11) CE _D and the ignition timing SA are calculated (step S3). .

Then, based on the target air filling amount CE _D and the rotational speed N _ENG calculated in step S3, a target value θ _{IVC_D} of the closing timing IVC of the intake valve 21 is calculated. In this embodiment, as described above, the valve opening period of the intake valve 32 is kept constant, and the opening timing IVO of the intake valve 21 is calculated simultaneously with the calculation of the target value _{θIVC_D} of the closing timing IVO of the intake valve 21. Target value θ _{IVO_D is} also calculated. Further, based on the target air filling amount CE _D and the rotational speed N _ENG calculated in step S3, the target value of the valve timing of the exhaust valve 22, that is, the target value θ _{EVO_D} of the opening timing EVO of the exhaust valve 22, and A target value θ _{EVC_D} of the closing timing EVC is calculated (step S4). Furthermore, based on the rotational speed _{N ENG} and the calculated target air charge amount CE _D, it calculates a target throttle opening TVO _D is a target value of the opening degree TVO of the throttle valve 57 (step S5). Details will be described later of a method of calculating the target value theta _{IVC_D} and target throttle opening TVO _D of the closing timing IVC of the intake valve 21.

Thereafter, the calculated fuel injection amount FP, ignition timing SA, intake valve 21 opening timing IVO target value θ _{IVO_D} , intake valve 21 closing timing IVC target value θ _{IVC_D} , exhaust valve 22 opening timing EVO target value theta _{EVO_D,} target value theta _{EVC_D} the closing timing EVC of the exhaust valve 22, based on the target throttle opening TVO _D, these target values to drive the actuators as satisfied (step S6). Specifically, the signals θ _{IVO_D} and θ _{IVC_D} are output to the intake camshaft phase varying mechanism 32. Then, the intake camshaft phase varying mechanism 32 operates so that the phase of the intake camshaft 31 relative to the crankshaft 14 becomes a value corresponding to _{θIVO_D} and _{θIVC_D} . The signals θ _{EVO_D} and θ _{EVC_D} are output to the exhaust camshaft phase varying mechanism 42. Then, the exhaust camshaft phase varying mechanism 42 operates so that the phase of the exhaust camshaft 41 with respect to the crankshaft 14 has a value corresponding to θ _{EVO_D} and θ _{EVC_D} . Signal TVO _D is outputted to the throttle actuator 58. Then, as the opening degree TVO of the throttle valve 57 becomes a value corresponding to the TVO _D, the throttle actuator 58 is operated. The signal FP is output to the fuel system 54. An amount of fuel corresponding to FP per cylinder cycle is injected from the fuel injection valve 53. Then, the signal SA is output to the ignition system 52. At a time corresponding to SA in the cylinder cycle, the spark plug 51 ignites, and the air-fuel mixture in the combustion chamber 17 is ignited. As a result, a target torque mainly determined from the depression amount α of the accelerator pedal is generated from the engine body 1 by igniting and burning the required amount of air / fuel mixture at an appropriate time. Is done.

Then, the target value theta _{IVO_D} closing timing of the intake valve 21, theta _{IVC_D,} target value theta _{EVO_D} closing timing of the exhaust valve 22, θ _{EVC_D} and target throttle opening TVO _D calculation methods namely the intake valve 21, exhaust A specific control method for the valve 22 and the throttle valve 57 will be described. In the following description, the numerical values indicating the timing and period of the opening / closing timing of the intake valve 21 and the exhaust valve 22 are based on the crank angle, BTDC is before top dead center, and ATDC is after top dead center. , BBDC means before bottom dead center, and ABDC means after bottom dead center.

In less than a reference charge amount _CE D _base the target air charge amount CE _D low load of the engine is preset area (area A in FIG. 3, FIGS. 4 and 8), the opening and closing timing IVO of the intake valve 21, close timing EVO of IVC and exhaust valve 22, EVC is controlled to be constant regardless of the rotational speed _{N ENG,} the throttle opening TVO is controlled to vary in accordance with the target air charge amount CE _D. For example, as shown in FIG. 5A, the opening timing IVO of the intake valve 21 is controlled to a value of about ATDC 30 ° C. retarded from TDC, and the closing timing IVC of the intake valve 21 is sufficiently retarded from BDC. The ABDC is controlled to a value of about 100 ° C. Further, the opening timing EVO of the exhaust valve 22 is controlled to a value of about BBDC 25 ° CA advanced from BDC, and the closing timing EVC of the exhaust valve 22 is controlled to a value of about ATDC 20 ° A retarded from TDC. Then, the throttle opening TVO is the open side with an increase in the target air charge amount CE _D as shown in FIG. 4, i.e., is controlled on the side where the opening area of the intake passage is increased. Here, for example, the reference charge amount CE _D _base is the maximum order of half the value of the air charge amount in the engine body 1.

  As shown in FIG. 6, the air filling amount CE in the cylinder 11 has the largest closing timing IVC of the intake valve 21 in the vicinity of BDC in the low speed region, and the air in the cylinder 11 on the retard side than that. Decreases to blow back to the intake passage side. Accordingly, when the closing timing IVC of the intake valve 21 is controlled to about ABDC 100 ° C. so as to be retarded from the time when the air filling amount CE becomes maximum as described above, the air filling amount CE in the cylinder 11 is controlled. Can be kept small enough.

Further, the load is high target air charge amount CE _D of the engine the reference filling amount _CE D greater than _base region (FIG. 3, the region B of FIG. 4 and FIG. 8), the throttle opening TVO is the target air charge amount It is controlled to be constant for each revolution speed _{N ENG} regardless of CE _D, opening and closing timing IVO of the intake valve 21, IVC is controlled to vary in accordance with the target air charge amount CE _D. Specifically, the throttle opening TVO is controlled near the fully open position. Then, the closing timing IVC of the intake valve 21 is controlled to the advance side as indicated by the arrow in FIG. 6 along with the increase of the target air charge amount CE _D on the retard side of the timing when the air charge amount CE becomes maximum. is, the opening timing IVO of the intake valve 21 in response thereto is controlled to the advance side with increasing target air charge amount CE _D.

As described above, the air filling amount CE decreases as the closing timing IVC of the intake valve 21 is retarded on the retard side of the timing when the air filling amount CE is maximized. Therefore, in the region B, by the closing timing IVC of the intake valve 21 is controlled to the advance side, so that the air charge amount CE is increased target air charge amount CE _D is satisfied. In particular, in this embodiment, the throttle opening TVO is controlled in the vicinity of the fully open position, and the pumping loss due to the throttle valve 57 reducing the opening area of the intake passage is reduced, so that the engine operating efficiency is increased.

Here, the throttle opening TVO is controlled so as to change in accordance with the rotational speed N _ENG in all engine operating ranges. Specifically, it is controlled to the opening side as the rotational speed N _ENG increases. Then, the closing timing IVC and open timing IVO of the intake valve 21, the entire load range of the area B and the engine (3, region C where the target air charge amount CE _D becomes maximum in FIG. 4 and FIG. 8), i.e. reference In an area larger than the filling amount CE _D _base, control is performed so as to change according to the rotational speed N _ENG . Specifically, in the region where the rotational speed N _ENG is less than the reference rotational speed, the rotational speed N _ENG is controlled to be advanced as the rotational speed N _ENG is increased. In the region where the rotational speed N _ENG is higher than the reference rotational speed, the retardation is increased as the rotational speed is increased. Controlled to the side. Details of the control of the closing timing IVC of the intake valve 21 in this region will be described below.

First, when the rotational speed N _ENG is as low as N1 and the target air charge amount CE _D is maximum, the closing timing IVC of the intake valve 21 is sufficiently retarded from the timing when the air charge amount CE is maximum, for example, It is controlled to about ABDC 60 ° C. A as indicated by (b) in FIG. 5 and point P1 in FIG.

  Here, in the low rotation region, since the air flow in the cylinder 11 is small, there is a high possibility that self-ignition occurs in the cylinder 11 as the temperature rises during compression. Therefore, in this region, it is desirable to suppress the air filling amount CE in the cylinder 11 to be small and to prevent the temperature from rising excessively. On the other hand, in this control, the closing timing IVC of the intake valve 21 is controlled to the sufficiently retarded side as described above, and the air filling amount CE in the cylinder 11 and thus the temperature in the cylinder 11 at the time of compression are set. Since it is suppressed that it becomes excessive, generation | occurrence | production of the said self-ignition is suppressed. In particular, the engine main body 1 has a geometric compression ratio set to a relatively high value of 14 and is likely to self-ignite, so this control works more effectively.

Opening timing IVO of the intake valve 21 when the rotational speed _{N ENG,} the target air charge amount CE _D is up to N1, corresponding to the closing timing IVC of the intake valve 21, for example, controlled to about BTDC 10 ° C. A Is done. The opening timing EVO of the exhaust valve 41 is controlled to, for example, about ATDC 5 ° C., and the overlap period during which both the intake valve 21 and the exhaust valve 41 are open is controlled to about 15 ° A. At this time, the closing timing EVC of the exhaust valve 41 is controlled to about BBDC 40 ° C. A corresponding to the opening timing EVO.

Next, in the region from the rotational speed N1 to the reference rotational speed N2 (> N1), the closing timing IVC of the intake valve 21 is controlled to be retarded from the timing at which the air charge amount CE is maximized, and the rotational speed. It is controlled to the advance side as N _ENG rises. For example, the closing timing IVC of the intake valve 21 is such that when the target air charge amount CE _D is maximum at the rotational speed N2, the air charge amount CE is maximum as shown in FIG. 5C and point P2 in FIG. It is advanced to about ABDC 30 ° C. When the engine speed N _ENG increases to increase the air flow and reduce the possibility of abnormal combustion, the air charge amount CE in the cylinder 11 can be increased. Therefore, in this region, as the engine speed N _ENG increases, the closing timing IVC of the intake valve 21 is controlled to the advance side to increase the air filling amount CE in the cylinder 11 and burn more fuel. Thus, the engine output and thus the engine operating efficiency are increased.

Here, as shown in FIG. 7, when the rotational speed N _ENG increases, the inertia of the intake air increases, and the timing when the air charge amount CE becomes maximum moves to the retard side. Further, as described above, on the retard side of the time when the air filling amount CE is maximized, the amount of air blown back into the intake passage decreases as the closing timing IVC of the intake valve 21 advances, and the air filling amount. CE increases. Therefore, when the closing timing IVC of the intake valve 21 is controlled to the advance side as the rotational speed increases as described above, the air filling amount CE of the cylinder 11 is sufficient due to the effect of reducing the blowback amount and the effect of increasing the inertia. Will be enhanced. In particular, if the closing timing IVC of the intake valve 21 is advanced to the vicinity of the time when the air filling amount CE is maximized, the charging efficiency is increased.

Further, in the region where the rotational speed N _ENG is from N1 to N2 and the target air charge amount CE _D is maximized, the opening timing IVO of the intake valve 21 is controlled to the advance side as the rotational speed N _ENG increases. In addition, the closing timing EVC and the opening timing EVO of the exhaust valve 22 are controlled to the retard side. As a result, the overlap period of the intake valve 21 and the exhaust valve 41 is controlled to increase as the rotational speed N _ENG increases. Here, in the region where the rotational speed N _ENG is low, if the overlap period is long, the exhaust gas flows backward to the intake side and the charging efficiency is lowered. However, in the region where the rotational speed N _ENG is high, the overlap period should be increased. Thus, the scavenging performance in the cylinder 11 can be enhanced. Therefore, by controlling the overlap period to increase as the rotational speed N _ENG increases as described above, the amount of fresh air in the cylinder 11 is appropriately increased and increased according to the increased amount of air. By injecting the fuel from the fuel injection valve 53 and burning it, the engine output is improved and the engine operating efficiency is increased. For example, the opening timing IVO of the intake valve 21 at the rotational speed N2 when the target air charge amount CE _D is maximum is controlled to about BTDC40 ℃ A, closing timing EVC of the exhaust valve 41 is controlled to about ATDC20 ℃ A, The overlap period is controlled to about 60 ° C., which is longer than the overlap period value of 15 ° C. at the rotation speed N1. At this time, the opening timing EVO of the exhaust valve 41 is controlled to about BBDC 25 ° C. A corresponding to the closing timing EVC.

  The rotational speed N1 is a value of about 1000 rpm, for example, and the reference rotational speed N2 is a value of about 2000 rpm, for example.

Finally, in the region from the rotational speed N2 to the rotational speed N3 (> N2), the closing timing IVC of the intake valve 21 is controlled to the retard side as the rotational speed _NENG increases. For example, the target air charge amount CE _D at a rotational speed N3 is at the maximum, as shown in the point P3 (d) and 7 of Figure 5, is retarded to about ABDC60 ℃ A. The rotation speed N3 is a value of about 7000 rpm, for example.

In the present embodiment, when the target air filling amount CE _D is the maximum and the rotational speed N _ENG is N2, the closing timing IVC of the intake valve 21 is controlled around the time when the air filling amount CE is maximized. When the rotational speed N _ENG increases, as described above, the timing when the air charge amount CE becomes maximum due to the inertia of the intake air moves toward the retard side. Therefore, in the high rotation speed region from the rotation speed N2 to the rotation speed N3, the closing timing IVC of the intake valve 21 is controlled to the retard side as the rotation speed _NENG increases, so that the air charge amount CE is at the maximum value. It is maintained substantially constant.

As described above, the possibility of occurrence of abnormal combustion decreases as the rotational speed N _ENG increases, and there is almost no possibility of abnormal combustion occurring in a region where the rotational speed exceeds the rotational speed N2. Accordingly, in a region where the rotational speed N _ENG, the target air charge amount CE _D is maximum N2 above, air charge the closing timing IVC is controlled to the retard side with increasing rotational speed N _ENG of the intake valve 21 By maintaining the CE at the maximum value, the maximum amount of fuel can be burned, and the engine output and thus the engine operating efficiency can be maintained at the maximum.

Further, in the region where the rotational speed N _ENG is N2 or more and the target air charge amount CE _D is maximum, the opening timing EVO of the exhaust valve 22 is controlled to the advance side as the rotational speed N _ENG increases, The engine operating efficiency is more reliably maintained by keeping the exhaust resistance smaller as the number N _ENG increases. For example, the target air charge amount CE _D is at a maximum condition at a rotation number N3, the opening timing EVO of the exhaust valve 22 is advanced to about BBDC35 ℃ A. Under this condition, the closing timing ECV of the exhaust valve 22 is advanced to about ATDC 10 ° C. corresponding to the opening timing EVO of the exhaust valve 22, and the opening timing IVO of the intake valve 21 is the closing timing of the intake valve 21. The angle is delayed to about BTDC 10 ° C. corresponding to the timing IVC.

  With the control as described above, in the engine body 1, the self-ignition is more reliably suppressed by sufficiently suppressing the air filling amount CE of the cylinder 11 in the low rotation region, and in the middle and high rotation regions. The output is maintained when the air filling amount CE of the cylinder 11 is sufficiently secured.

  Here, in the region of the rotational speed N2 to N3, the closing timing IVC of the intake valve 21 may be controlled to be retarded from the timing at which the air charge amount CE is maximized. In addition, in the region of the rotational speed N2 to N3, the control for making the closing timing IVC of the intake valve 21 retarded is not performed, but the control for making the closing timing IVC advanced as the rotational speed increases toward the total rotational speed. You may do it.

  In the low load region A, the closing timing IVC of the intake valve 21 may be changed. However, if the closing timing IVC of the intake valve 21 is kept constant in the low load region A, the control width of the valve timing IVC of the intake valve 21 can be kept small as a whole. For this reason, it is possible to suppress an adverse effect associated with the change in the valve timing. For example, a situation in which the overlap amount with the exhaust valve 22 cannot be properly maintained due to a change in the opening timing IVO of the intake valve 21 with a change in the closing timing IVC can be avoided more reliably. This is particularly effective when the valve opening period of the intake valve 21 is kept constant as in the present embodiment.

  Further, the detailed structure of various actuators is not limited to the above.

  In addition, specific values such as the opening / closing timings IVO and IVC of the intake valve 21, the opening / closing timings EVO and ECV of the exhaust valve 22, the reference filling amount, and the rotational speeds N1, N2, and N3 are not limited to the above.

1 Engine Body 11 Cylinder 14 Crankshaft 17 Combustion Chamber 21 Intake Valve (Intake Valve)
22 Exhaust valve (exhaust valve)
30 Intake valve drive mechanism (valve drive mechanism)
31 Intake camshaft (camshaft)
40 Exhaust valve drive mechanism (valve drive mechanism)
56 Throttle body (throttle drive mechanism)
57 Throttle valve (pressure control means)
100 Engine controller (control means)

Claims (14)

A cylinder that accommodates a reciprocating piston and forms a combustion chamber; an intake passage through which air introduced into the cylinder passes; and an intake valve that can block inflow of air from the intake passage into the cylinder; A method of controlling an internal combustion engine having an exhaust passage through which exhaust exhausted from the cylinder passes, and an exhaust valve capable of blocking outflow of exhaust from the cylinder to the exhaust passage,
The valve closing timing of the intake valve is retarded from the timing at which the amount of air introduced from the intake passage into the cylinder is maximized, and the rotational speed of the internal combustion engine is the same. As the target air charge amount, which is the target value of the air amount introduced into the cylinder, increases, the target air charge amount is maximum and the rotational speed is less than a preset reference rotational speed. A control method for an internal combustion engine, characterized in that control is performed so that the angle of advance increases as the rotational speed increases. A cylinder that accommodates a reciprocating piston and forms a combustion chamber; an intake passage through which air introduced into the cylinder passes; and an intake valve that can block inflow of air from the intake passage into the cylinder; A method of controlling an internal combustion engine having an exhaust passage through which exhaust exhausted from the cylinder passes, and an exhaust valve capable of blocking outflow of exhaust from the cylinder to the exhaust passage,
Under the condition that the closing timing of the intake valve is retarded from the timing at which the amount of air flowing into the cylinder from the intake passage becomes maximum, and the rotational speed of the internal combustion engine is the same. While controlling to advance as the target air charge amount that is the target value of the air amount introduced into the cylinder increases,
When the rotational speed is less than a preset reference rotational speed under the condition that the target air filling amount is maximum, the valve closing timing of the intake valve is controlled to advance as the rotational speed increases. On the other hand, when the rotational speed is equal to or higher than the reference rotational speed under the condition that the target air filling amount is maximized, the closing timing of the intake valve is retarded as the rotational speed increases. A control method for an internal combustion engine, characterized by controlling. A control method for an internal combustion engine according to claim 2,
When the rotational speed is equal to or higher than the reference rotational speed under the condition that the target air filling amount is maximized, the valve opening timing of the exhaust valve is controlled to advance according to the increase in the rotational speed. A control method of an internal combustion engine characterized by the above. A control method for an internal combustion engine according to claim 2 or 3,
When the rotational speed is less than the reference rotational speed under the condition that the target air filling amount is maximum, the opening timing of the intake valve is advanced and the exhaust valve is closed as the rotational speed increases. A control method for an internal combustion engine, wherein the valve timing is controlled to be retarded. A control method for an internal combustion engine according to any one of claims 1 to 4,
A control method for an internal combustion engine, wherein the closing timing of the intake valve is controlled to a constant value over an entire operating region in an operating region where the target air charging amount is equal to or less than a preset reference charging amount. A control method for an internal combustion engine according to claim 5,
Using pressure control means provided in the intake passage and capable of controlling the pressure in the intake passage,
Control of an internal combustion engine, wherein the pressure control means increases the pressure in the intake passage as the target air filling amount increases in an operating region where the target air filling amount is equal to or less than the reference filling amount. Method. A cylinder that houses a reciprocating piston and that forms a combustion chamber; an intake passage through which gas introduced into the cylinder passes; and an intake valve that can block the flow of gas from the intake passage into the cylinder; A control system for an internal combustion engine having an exhaust passage through which exhaust discharged from the cylinder passes, and an exhaust valve capable of blocking outflow of exhaust from the cylinder to the exhaust passage,
A valve drive mechanism for periodically opening and closing the intake valve and the exhaust valve;
Control means for controlling the valve drive mechanism,
The control means controls the valve driving mechanism so that the closing timing of the intake valve is retarded from the timing at which the amount of air flowing into the cylinder from the intake passage becomes maximum. ,
The control means includes the valve drive mechanism, and a target air filling in which the closing timing of the intake valve is a target value of the amount of air introduced into the cylinder under the condition that the rotation speed of the internal combustion engine is the same. The intake valve closing timing is such that the target air filling amount is the maximum and the rotational speed is less than a preset reference rotational speed so that the larger the amount is, the closer to the advance side. A control system for an internal combustion engine, wherein the control is performed so that the angle of advance increases as the rotational speed increases. A cylinder that houses a reciprocating piston and that forms a combustion chamber; an intake passage through which gas introduced into the cylinder passes; and an intake valve that can block the flow of gas from the intake passage into the cylinder; A control system for an internal combustion engine having an exhaust passage through which exhaust discharged from the cylinder passes, and an exhaust valve capable of blocking outflow of exhaust from the cylinder to the exhaust passage,
A valve drive mechanism for periodically opening and closing the intake valve and the exhaust valve;
Control means for controlling the valve drive mechanism,
The control means includes the valve drive mechanism, wherein the closing timing of the intake valve is retarded from the timing at which the amount of air flowing into the cylinder from the intake passage becomes maximum; Under the condition that the rotational speeds of the cylinders are the same, the larger the target air charge amount, which is the target value of the air amount introduced into the cylinder, is controlled to be advanced,
The control means causes the valve drive mechanism to increase the rotation speed of the intake valve when the target air filling amount is maximum and the rotation speed is less than a preset reference rotation speed. The more the target air charge amount is maximum and the rotation speed is equal to or higher than the reference rotation speed, the more the intake valve closing timing increases as the rotation speed increases. A control system for an internal combustion engine, characterized in that control is performed so as to be on the side. The control system for an internal combustion engine according to claim 8,
The control means advances the valve opening timing of the exhaust valve in accordance with the increase in the rotational speed when the rotational speed is equal to or higher than the reference rotational speed under the condition that the target air filling amount is maximized. And a control system for an internal combustion engine, which controls the valve drive mechanism. A control system for an internal combustion engine according to claim 8 or 9,
The valve drive mechanism includes a camshaft that is driven by a crankshaft connected to the piston to drive the intake valve and the exhaust valve, and a phase variable mechanism that changes a phase of the camshaft with respect to the crankshaft.
The control system for an internal combustion engine, wherein the control means controls the valve closing timing of the intake valve by driving the phase varying mechanism to change the phase of the camshaft with respect to the crankshaft. A control system for an internal combustion engine according to claim 10,
The control means controls the valve drive mechanism so that the closing timing of the intake valve is constant over the entire operation region in the operation region where the target air filling amount is equal to or less than a preset reference filling amount. A control system for an internal combustion engine. An internal combustion engine control system according to claim 10 or 11,
The control means drives the phase variable mechanism to change the phase of the camshaft with respect to the crankshaft, so that the rotation speed is less than the reference rotation speed under the condition that the target air filling amount is maximized. In this case, the control system for the internal combustion engine controls to advance the opening timing of the intake valve and retard the closing timing of the exhaust valve in accordance with the increase in the rotational speed. A control system for an internal combustion engine according to any one of claims 7 to 12,
A control system for an internal combustion engine, wherein the cylinder has a geometric compression ratio of 13 or more. A control system for an internal combustion engine according to any one of claims 7 to 13,
A throttle valve provided in the intake passage and capable of changing a flow passage area of the intake passage;
A throttle drive mechanism for driving the throttle valve;
The control means controls the throttle drive mechanism so that the throttle valve increases the opening area as the target air filling amount increases in an operation region where the target air filling amount is equal to or less than the reference filling amount. A control system for an internal combustion engine.

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