Internal combustion engine control device

Abstract

Internal combustion engine control device for controlling an internal combustion engine, comprising an air flow rate sensor (106) for measuring an air quantity, represented as an actual air quantity, wherein the air flows into a cylinder (117), and a throttle valve (104) for adjusting the air quantity, wherein the internal combustion engine control device comprises: a throttle valve control section for controlling a throttle valve opening degree of the throttle valve (104) in order to achieve a preset throttle valve opening degree, which is set depending on a target air quantity to realize a required torque;and a throttle opening degree correction section for correcting the preset throttle opening degree on the basis of the target air quantity during a fuel interruption that stops the supply of fuel to the internal combustion engine and an actual air quantity measured by the air flow rate sensor (106), characterized in that the throttle opening degree correction section corrects the preset throttle opening degree when a difference between the target air quantity during the fuel interruption and the actual air quantity measured by the air flow rate sensor (106) is greater than or equal to a preset value.

Description

Technical FieldThe present invention relates to an internal combustion engine control device for controlling an internal combustion engine including a throttle valve for adjusting an amount of air flowing into a cylinder of the internal combustion engine.Background AreaAs CO 2- regulation becomes more intense, technologies for low fuel consumption such as idle stop, mass EGR, and the like have been introduced, and model-based controllers have been put into practical use for effectively developing such complex control processes. Specifically, the throttle valve of an internal combustion engine functions as a key means for adjusting the amount of air flowing into the cylinders to control the shaft torque of the internal combustion engine. Model-based controls based on the model of a throttle opening degree and an opening area, i.e., a throttle opening degree model, have been introduced.One problem with model-based controls is a model error. The modeling error is caused by factors including engine difference and aging. The throttle opening degree model referred to above particularly suffers from the problem of deposits adhering to the vicinity of a throttle flow passage. Further, in recent years, because LP-EGR engines that introduce EGR upstream of a turbocharger to meet fuel cost requirements have started to appear on the market, the modeling error has tended to become larger than before due to the adhesion and removal of deposits.Processes for learning a failure of a throttle opening degree model due to deposits include, for example, a process for learning a valve opening degree and loss, i.e., a deviation between an opening degree and a flow rate model in an idling range disclosed in Patent Document 1, and a process of learning an opening degree-opening area model in all the ranges disclosed in Patent Document 2. Patent Document 3 discloses an engine control apparatus for controlling an engine mounted with an electronically controlled throttle valve, wherein when the electronically controlled throttle valve is fully opened, a target air volume based on the engine load is compared with the air volume measured by an intake air volume meter to correct a target maximum air volume volume volume based on the results of such comparison and correct the target air volume based on such a corrected target maximum air volume. Patent Document 4 shows a method for controlling an internal combustion engine, wherein a predefined number of cylinders is deactivated in predetermined operating states, and the torque of the internal combustion engine desired by the driver is maintained independently of the number of deactivated cylinders by influencing the charge, characterized in that, in addition to influencing the charge in the transition phase, the ignition angle is additionally corrected and / or the number of deactivated cylinders is influenced in the event of a change in the number of deactivated cylinders.Prior Art DocumentPatent DocumentsPatent Document 1: JP 2006-138 270 APatent Document 2: JP 2016-217 176 APatent Document 3: US 2008 / 0 066 718 A1Patent Document 4: DE 196 19 320 A1SUMMARY OF THE INVENTIONProblems to be Solved by the InventionHowever, according to the process disclosed in Patent Document 1, the learning range is limited to the engine idling while the engine cools or warms up. Therefore, the disclosed process may fail to achieve sufficient accuracy with respect to idle-stop vehicles that have become more recently because they reduce learning opportunities. Further, the process disclosed in Patent Document 2 is problematic in terms of learning of the opening degree, particularly when the throttle opening degree is large. For example, in the vicinity of a full throttle opening, pressure pulsations occurring in an intake pipe may cause the air flow rate to be detected as being larger than an actual value, which tends to result in an erroneously learned throttle opening area.The present invention is directed to solving the above problems. It is an object of the present invention to provide an internal combustion engine control apparatus for detecting the adhesion and removal of deposits and for quickly correcting a throttle opening degree.Means for Solving the ProblemsIn order to solve the above problems, the present invention is carried out according to the appended claims.Advantages of the InventionAccording to the present invention, it is possible to provide an engine control device for detecting the adhesion and removal of deposits and for quickly correcting a throttle opening degree.Brief Description of the DrawingsFIG. 1 is a view illustrating an example of an internal combustion engine to which the present invention is applied. FIG. 2 is a diagram illustrating an example of a throttle opening degree model. FIG. 3 is a diagram illustrating an example of the relationship between a throttle opening degree and a Sonic opening degree in fuel cut. FIG. 4 is a diagram illustrating an example of a flowchart for correcting a throttle opening degree according to the present invention. FIG. 5 is a diagram illustrating an example of throttle opening degree correction blocks. FIG. 6 is a diagram illustrating an example of a flowchart for correcting an effective opening area according to the present invention. FIG. 7 is a diagram illustrating an example of timing graphics at the time when the present invention is applied to removing debris. FIG. 8 is a diagram illustrating an example of timing graphics at the time when the present invention is applied to the adhesion of deposits. FIG. 9 is a view illustrating another example of an internal combustion engine to which the present invention is applied. FIG. 10 is a diagram illustrating another example of throttle opening degree correction blocks. FIG. 11 is a diagram illustrating another example of a flowchart for correcting an effective opening area according to the present invention. FIG. 12 is a diagram illustrating an example of timing graphics at the time when the present invention is applied. FIG. 13 is a diagram illustrating another example of timing graphics at the time when the present invention is applied to the adhesion of deposits.MODES FOR CARRYING OUT THE INVENTIONEmbodiments of the present invention will be described below with reference to the drawings.Embodiment 1FIG. 1 illustrates an example of an internal combustion engine to which the present invention is applied. Although an internal combustion engine including a turbocharger 105 is described by way of example according to the present embodiment, the present invention is not limited to the illustrated example, but is equally applicable to other arrangements.The internal combustion engine is controlled by a control device, not shown, i.e., an engine control unit (ECU). The ECU controls air control devices, i.e., a throttle valve 104, intake and exhaust variable valves 102, the turbocharger 105, and the like, to realize a demand torque requested by the driver or a driving support device. An air flow rate sensor 106 detects the fresh air flow rate that is newly drawn in from the outside. For throttle control, for example, a target air amount flowing through the throttle valve 104 is calculated from the demand torque, and a target throttle opening degree for the throttle valve 104 is calculated from the target air amount according to a process described later. A pressure sensor, not shown, is disposed between the turbocharger 105 and the variable intake and exhaust valves 102. For turbocharger control, the turbocharger 105 is FB-controlled, i.e., feedback-controlled, to balance the air pressure in an intake chamber 110 disposed downstream of an intake pipe 111 or the throttle valve 104 to a preset pressure determined depending on a driving state using a detected value from the pressure sensor. Further, a fuel cut control process is executed when the vehicle speed is high at the time when the driver releases the accelerator pedal to stop fuel injection from a fuel injection valve 101. Alternatively, an FB control process is executed to cause an air / fuel ratio sensor, not shown, mounted on an exhaust pipe 109 to have an existing value to keep the purification efficiency of a catalytic converter 108. The ECU performs the above control processes using model-based controls that employ a characteristic model of the devices and a dynamic model of physical quantities. An opening degree model of the throttle valve 104 according to the present embodiment is employed based on the following equations (1) to (3) representing opening formulas:In the equations, dm v / dt, and k represent a mass flow rate and a ratio of specific heat of air flowing through the throttle valve 104, μ v A v an effective opening area, P up, T up, R up a pressure and a temperature and a gas constant upstream of the throttle valve 104, respectively, and P dn a pressure downstream of the throttle valve 104.FIG. 2 illustrates an example of an opening degree model of the throttle 104. The opening degree model of the throttle valve 104 is experimentally determined according to Equations (1) to (3) representing opening formulas. Specifically, the opening degree of the throttle valve 104 is changed at a constant engine speed, and the mass flow rate dm v / dt of the air, the pressure P up and the temperature upstream of the throttle valve 104, and the pressure P dn downstream of the throttle valve 104 are measured, where the gas constant R up and the specific heat ratio k are fresh air values of 274 and 1.4, respectively. The effective opening area μ v A v can be calculated from these measurement values according to Equations (1) and (2) or Equation (3). In FIG. 2, the opening degree A represents the opening degree of the throttle valve 104 while being fully closed, and the opening degree B represents the opening degree of the throttle valve 104 while being fully opened. A deviation from a throttle opening degree sensor is corrected by a process for learning the origin of the throttle opening degree, which will be described later. The throttle opening degree sensor is integrally connected to the throttle valve 104.The opening degree D in FIG. 2 represents a Sonic opening degree. When the pressure upstream of the throttle valve 104 is the atmospheric pressure, i.e., 101 kPa, for example, the throttle opening degree at which the pressure downstream of the throttle valve 104 is less than or equal to 53 kPa represents the Sonic opening degree according to the opening formulas (1) and (2). In other words, the present embodiment focuses on the fact that, assuming that the throttle valve 104 is closed to an opening degree that is smaller than the sonic opening degree, the flow rate of the air flowing through the throttle valve 104 according to the opening formulas (1) and (2) has a constant value depending on the pressure upstream of the throttle valve 104 regardless of the engine speed.FIG. 3 illustrates an example of the relationship between a throttle opening degree and a sonic opening degree in fuel cut. When the fuel supply is cut off, the throttle opening degree is maintained at a constant opening degree after the throttle valve is moved in a more closing direction than when the engine is in the steady operation. This control process serves two purposes to cause the engine brake to operate and to prevent the amount of oxygen stored in the catalytic converter from increasing. At this time, the pressure downstream of the throttle valve 104 has a value of approximately 30 kPa. As illustrated in FIG. 3, the opening degree of the throttle valve 104 is smaller than the sonic opening degree when the fuel supply is cut off. Therefore, it is possible to determine whether or not the opening degree of the throttle valve 104 is equal to or less than the sonic opening degree, based on a fuel cut flag calculated by the ECU, although the sonic opening degree is not calculated strictly. The following description is based on the premise that the relationship illustrated in FIG. 3 is effective.FIG. 4 illustrates an example of a flowchart for correcting the throttle opening degree according to the present embodiment. In step S401, it is confirmed whether the throttle valve 104 is operating regularly, i.e., whether the throttle valve 104 is stuck or not. It is also confirmed whether the throttle opening degree sensor is operating regularly, i.e., whether or not the dual system sensor outputs in mutual agreement. It is confirmed that the air flow rate sensor 106 is regularly operating, i.e., has not undergone disconnection and a correction amount for air / fuel ratio feedback does not exceed a preset value. If the sensors and the devices are regular in step S401, control goes to step S402. In step S402, it is confirmed whether or not the process for learning the origin of the throttle opening degree is completed. When the process for learning the origin of the throttle opening degree is finished, control goes to step S 403. When the process for learning the origin of the throttle opening degree is not finished, control goes to step S 405.In step S 405 the process for learning the origin of the throttle opening degree is executed. According to the process for learning the origin of the throttle opening degree, the detected value obtained from the throttle opening degree sensor at the time when a full close command is given to the throttle valve 104 is learned as A in FIG. 2. In this case, the detected value obtained from the throttle opening degree sensor at the time when a full opening command is given to the throttle valve 104 may be learned as B in FIG. 2. The timing for the process of learning the origin of the throttle opening degree should preferably be immediately after the engine is turned off. When the learned value is lost immediately after the battery is replaced, the process of learning the origin of the throttle opening degree at the time of a first idle stop may be executed. By performing the process of learning the origin of the throttle opening degree, it is possible to reduce a deviation from the throttle opening degree model based on the throttle opening degree sensor, thereby increasing the accuracy of the correction of the throttle opening degree according to the present embodiment.In step S 403, it is determined whether or not the difference between an actual air amount and a target air amount at fuel cut is larger than a preset value. If the difference is larger than the preset value, control goes to step S404 to perform correction of the throttle opening degree. The value set in advance in step S403 is a value determined depending on the effect that an error of the throttle opening degree model has on variation of the idle speed and transmission shock. For example, it is assumed that the effective opening area of 1 mm 2 is reduced by the adhesion of deposits. When the flow rate of air during idling is approximately 200 g / min, the engine output is lowered by at least approximately 7% (14.4 / 200) because a fresh air flow rate of approximately 14.4 g / min is decreased according to the opening formulas (Equation 1) and (Equation 2). A situation where a real engine experiences out-of-round idle or transmission shock due to the above reduction in engine output is studied experimentally. The above preset value may be set in a manner of preventing the engine from undergoing out-of-round idling or transmission shock. Details of the processing of step S 404 will be described below with reference to FIGS. 5 and 6.FIG. 5 illustrates an example of throttle opening degree correction blocks according to the present embodiment. The throttle opening degree correction blocks generally include three blocks. A block B501 is a block for calculating a target effective opening area for the throttle valve 104 depending on a target air amount calculated from the required torque. Here, the block B 501 calculates the effective opening area target value according to the opening formulas (Equation 1) to (Equation 3). Specifically, a target air flow rate for dm v / dt, an upstream pressure target value for P up, an upstream temperature target value for T up and a downstream pressure target value for P dn are employed, and the gas constant R up and the specific heat ratio k are set to 273 and 1.4, respectively. The target effective opening area is calculated from μ v A v.The values such as that of the upstream pressure target value may be set to values obtained from an engine test bench test or the like, or may be calculated using the above model in a timely manner. A block B 502 is a block for calculating an effective opening area correction amount. Details of the block B 502 will be described later. A block B503 calculates a throttle opening degree from the sum of the target effective area and the effective area correction amount by inversely using the relationship between the throttle opening degree and the effective opening area illustrated in FIG. 2. The throttle opening degree can thus be corrected by adding an effective opening area correction amount described later to the target effective opening area calculated according to the opening formulas.FIG. 6 illustrates an example of a flowchart for correcting the effective opening area according to the present embodiment. In step S601, it is determined whether or not a change in the throttle opening degree is less than or equal to a preset value. If the change in the throttle opening degree is smaller than the preset value, control goes to step S602. In step S 602, it is determined whether or not a change in the actual air amount detected by the air flow rate sensor 106 is less than or equal to a preset value. When the change in the actual air amount is less than the preset value, control goes to step S 603. When the difference between the actual air amount and the target air amount is larger than a preset value in step S 603, control proceeds to step S 604. If not, control proceeds to step S605.In step S604, the effective opening area correction amount is decreased at a constant ratio set in advance to correct the throttle valve 104 in a closing direction. In this way, the air flow rate is prevented from increasing due to the removal of deposits, thereby preventing a transmission shock and a sudden increase in idle speed from occurring when removing deposits. When the difference between the actual air amount and the target air amount is less than a value (a negative value) set in advance in step S 605, control proceeds to step S 606. In step S606, the effective opening area correction amount is increased at a constant ratio set in advance to correct the throttle valve 104 in an opening direction. In this way, the air flow rate is prevented from decreasing due to the adhesion of deposits.In step S 604 and step S 606, the opening area is corrected at the constant ratios set in advance. This is to prevent the airflow rate from abruptly changing due to the correction of the throttle valve, thereby preventing the ride comfort from being impaired due to torque fluctuations during the correction process.FIG. 7 illustrates an example of timing graphics at the time when the present embodiment is applied to removing debris. At time A, the target air amount is decreased while the demand torque, not shown, decreases, whereupon the throttle opening degree starts to decrease. At time B while the fuel cut, i.e., the stop of the fuel injection, is in process, the correction of the effective opening area is not performed because the change in the actual air amount is larger than the preset value with the throttle opening degree kept constant. There are various factors regarding exhaust gas and riding comfort for causing the delay from time A to time B, and they will not be described below because their control is complex. At time C, the change in the actual air amount is smaller than the preset value, and the difference between the actual air amount and the target air amount is larger than the preset value. Consequently, a control process is performed to reduce the effective opening area correction amount at a constant ratio set in advance, and the actual throttle opening degree is corrected in a closing direction. Finally, at time D, the difference between the actual air amount and the target air amount is smaller than the preset value, causing the correction amount for the effective opening area to be constant, and also causing the actual throttle opening degree to be constant. According to the present embodiment, therefore, throttle correction is performed in the fuel cut, and the throttle opening degree is corrected in a closing direction in removing deposits.FIG. 8 illustrates an example of timing graphics at the time when the present embodiment is applied to deposit adhesion. At time A, the target air amount is decreased while the demand torque is decreased, whereupon the throttle opening is closed. At time B while the fuel cut is being performed, the correction of the effective opening area is not performed because the change in the actual air amount is larger than the preset value with the throttle opening degree kept constant. At time C, the change in the actual air amount is smaller than the preset value, and the difference between the actual air amount and the target air amount becomes negative and is smaller than the preset value. Consequently, the effective opening area correction amount is increased at a constant ratio set in advance, and the actual throttle opening degree is corrected in an opening direction. Finally, at time D, the difference between the actual air amount and the target air amount is larger than the preset value, causing the correction amount for the effective opening area to be constant, and also causing the actual throttle opening degree to be constant.As described above, the engine control device (ECU) according to the present embodiment controls the engine including the air flow rate sensor 106 for measuring the amount of air, i.e., the actual amount of air flowing into a cylinder 117, and the throttle valve 104 for adjusting the amount of air. The ECU includes a throttle control section for controlling the throttle opening degree of the throttle valve 104 to achieve a preset throttle opening degree set depending on a target air amount for realizing a demand torque, and a throttle opening degree correction section for correcting the preset throttle opening degree based on the target air amount at the fuel cut that stops the supply of fuel to the internal combustion engine and an actual air amount measured by the air flow rate sensor 106.Specifically, the throttle opening degree correction section corrects the preset throttle opening degree when the difference between the target air amount during fuel cut and the actual air amount measured by the air flow rate sensor 106 becomes equal to or larger than a preset value. More specifically, the throttle opening degree correcting section corrects the preset throttle opening degree by correcting the relationship between the preset throttle opening degree and the opening area based on the target air amount during fuel cut and the actual air amount measured by the air flow rate sensor 106.According to the present embodiment applied in this manner, the throttle correction is performed during the fuel cut, and the throttle opening degree is corrected in the adhesion of deposits in a closing direction. Since a change in the effective opening area due to the removal of deposits is generally larger than that due to the adhesion of deposits, the change rate of the correction amount for the effective opening area during the time interval from time C to time D illustrated in FIGS. 7 and 8 can be set to be larger at the removal of deposits than at the adhesion of deposits.By applying the present embodiment in this manner, a change in the opening area due to the accumulation and removal of deposits while the vehicle is running can be detected, thereby making it possible to correct the throttle opening degree before starting gear shifts or idling operations. As a result, it is possible to prevent transmission shocks and engine overrun during idling operations immediately after removing deposits. Further, even if the correction amount is cleared by the replacement of the battery or the like, the engine is prevented from being idling out of round due to a decrease in the flow rate in the adhesion of deposits because the throttle opening degree in the fuel cut is corrected quickly while the vehicle is running.Embodiment 2The present invention applied to an LP-EGR (Low Pressure Exhaust Gas Recirculation) system will be described below with reference to FIGS. 9 to 13.FIG. 9 illustrates another example of an internal combustion engine to which the present embodiment is applied. The internal combustion engine according to the present embodiment will be described below mainly with respect to its differences from the internal combustion engine illustrated in FIG. 1. In the engine according to the present embodiment, exhaust gases are recirculated from a position downstream of the catalytic converter 108 to a position upstream of the turbocharger 105 via an EGR cooler 113. Exhaust gas recirculation improves fuel costs in a boost pressure region. The ECU (Engine Control Unit), which is not shown, accurately controls the EGR flow rate by controlling an EGR value 114 of the LP-EGR system based on a measurement value from a differential pressure sensor 115. In the present system, since the EGR gases flow through the throttle valve 104, deposits are more likely to be attached and removed than in the internal combustion engine illustrated in FIG. 1. Further, since the EGR gases flowing through the throttle valve 104 cannot be detected by the air flow rate sensor 106, some measures are required to detect the EGR gases flowing through the throttle valve 104.FIG. 10 illustrates an example of throttle opening degree correction blocks according to the present embodiment. A block B 1001 calculates a target upstream pressure value and a target downstream pressure value from the engine speed and the target air amount, and determines that the air flow through the throttle 104 is in a sonic state when the ratio of the calculated pressures is less than (2 / (k+1)) (k-1). In other words, the block B 1001 determines that the velocity of the air flowing through the throttle valve 104 is the same as the sonic velocity. A block B 1003 calculates the difference between the target air amount and the actual air amount as an air error. A low pass filter may be included to calculate the air error to avoid the effect of noise from the air flow rate sensor. It is also preferable to calculate the pressure upstream of the throttle from an atmospheric pressure sensor, not shown, and an atmospheric temperature sensor, not shown.A block B 1002 calculates a variation in the air error in a fuel cut command, and determines that the flow rate is stable when the variation is less than a preset value and the amount of exhaust gases flowing through the throttle valve 104 is zero. Block B 1002 may determine whether or not the amount of exhaust gases flowing through the throttle plate 104 is zero based on the EGR flow rate detected by the differential pressure sensor 115 and a time period elapsed after the EGR valve 114 is closed. A block B 1004 calculates an effective opening area correction amount based on the air error at the time when the sonic state and the flow rate are determined. When the effective opening area correction amount is changed, a block 1005 corrects the throttle opening degree.FIG. 11 illustrates an example of a flowchart for correcting the effective opening area according to the present embodiment. In step S1101, it is determined whether or not a change in the throttle opening degree is less than or equal to a preset value. If the change in the throttle opening degree is smaller than the preset value, control goes to step S1102. In step S 1102, it is determined whether or not a change in the actual air amount detected by the air flow rate sensor 106 is less than or equal to a preset value. When the change in the actual air amount is less than the preset value, control goes to step S 1103. In step S 1103, it is determined whether or not the amount of exhaust gases flowing through the throttle valve 104 determined by, for example, the process described with reference to FIG. 10 is zero. When the amount of exhaust gases flowing through the throttle valve 104 is zero, control goes to step S1104. If the amount of exhaust gases flowing through the throttle 104 should be calculated more accurately, it may be calculated from a physical model ranging from the EGR valve to the throttle 104. With such an arrangement, the throttle opening degree of the actual air amount is prevented from being corrected erroneously because the amount of air flowing through the throttle valve 104 is in accordance with the air amount determined by the air flow rate sensor 106.When the difference between the actual air amount and the target air amount is larger than a value set in advance in step S 1100, control proceeds to step S 1105. If not, control proceeds to step S1106. In step S1105, the effective opening area correction amount is decreased at a constant ratio set in advance to correct the throttle valve 104 in a closing direction. In this way, when removing deposits, a transmission shock and a sudden increase in the idling speed are prevented from occurring. When the difference between the actual air amount and the target air amount is smaller than a value (a negative value) set in advance in step S 1106, control proceeds to step S 7107. In step S1107, the effective opening area correction amount is increased at a constant ratio set in advance to correct the throttle valve 104 in an opening direction. In this way, the engine is prevented from experiencing out-of-round idle when adhering deposits, particularly after the battery has been replaced.FIG. 12 illustrates an example of timing graphics at the time when the present embodiment is applied. At time A, the target air amount is decreased while the target torque is decreasing, whereupon the EGR valve and the throttle opening degree are started to be decreased. The timing B is a timing at which the EGR valve is fully closed. Until time C when the exhaust gases flowing through the throttle valve 104 become zero, correction of the effective opening area is not performed even if the difference between the actual air amount and the target air amount has a negative value and exceeds a preset value. By thus taking into account the flow rate of the exhaust gases flowing through the throttle valve 104, erroneous correction due to a decrease in the air flow rate at the time when the exhaust gases flow through the throttle valve 104 at the EGR flow rate is prevented.FIG. 13 illustrates an example of timing graphics at the time when the present embodiment is applied to the adhesion of deposits. At time A, the target air amount is decreased as the demand torque decreases, whereupon the EGR valve and the throttle opening are closed. The timing B is a timing at which the EGR valve is fully closed. Until time C when the exhaust gases flowing through the throttle valve 104 become zero, correction of the effective opening area is not performed even if the difference between the actual air amount and the target air amount has a negative value and exceeds a preset value. At time D, the effective opening area correction amount is decreased because the difference between the actual air amount and the target air amount is larger than the preset value, and the throttle opening degree is corrected in a closing direction.According to the present embodiment described above, a throttle opening degree correction section of the ECU corrects the throttle opening degree set in advance when the throttle opening degree of the throttle valve 104 becomes smaller than the sonic opening degree at which the speed of the air flowing through the throttle valve 104 becomes the sonic speed. In other words, the sonic opening degree at which the velocity of the air flowing through the throttle valve 104 becomes the sonic velocity is set in advance, and the throttle opening degree correction section corrects the preset throttle opening degree when the throttle opening degree of the throttle valve 104 becomes smaller than the sonic opening degree.In addition, the ECU according to the present embodiment includes a sonic speed determination section for determining the sonic opening degree at which the speed of the air flowing through the throttle valve 104 becomes the sonic speed, based on the ratio of the pressures before and after the throttle valve 104. The throttle opening degree correction section corrects the throttle opening degree set in advance when the sound velocity determination section determines that the sonic state is established. Further, the throttle opening degree correction section performs the above correction in a direction such that the throttle valve is closed when the actual air amount measured by the air flow rate sensor 106 is larger than the preset value instead of the target air amount during the fuel cut.In addition, the throttle opening degree correcting section does not correct the preset throttle opening degree even if the difference between the target air amount during fuel cut and the actual air amount measured by the air flow rate sensor 106 is equal to or larger than the preset value when the exhaust gases of the internal combustion engine are recirculated to a position upstream of the throttle valve 104 until the exhaust gases flowing through the throttle valve 104 have been removed. In addition, the throttle opening degree correcting section corrects the throttle opening degree set in advance after the exhaust gases flowing through the throttle valve 104 are removed when the exhaust gases of the internal combustion engine are recirculated to a position upstream of the throttle valve 104.In addition, the throttle opening degree correction section corrects the preset throttle opening degree on the basis of the target air amount during fuel cut and the actual air amount measured by the air flow rate sensor while the vehicle is running at vehicle speeds equal to or higher than a preset vehicle speed. Therefore, the throttle correction can be performed in a highly accurate manner by not correcting the throttle opening degree until the exhaust gases flowing through the throttle valve have been removed.Description of the Reference Numerals101 Fuel injection valve 102 Variable valve 103 Engine 104 Spark plug 105 Turbocharger 106 Air flow rate sensor 107 Charge air cooler 108 Catalytic converter 109 Exhaust pipe 110 Intake chamber 111 Intake pipe 112 EGR pipe 113 EGR cooler 114 LP-EGR control valve 115 Differential pressure sensor 116 Intake pipe upstream of the turbocharger

Claims

An internal combustion engine control apparatus for controlling an internal combustion engine including an air flow rate sensor (106) for measuring an amount of air represented as an actual amount of air, the air flowing into a cylinder (117), and a throttle valve (104) for adjusting the amount of air, the internal combustion engine control apparatus comprising: a throttle valve control portion for controlling a throttle opening degree of the throttle valve (104) to achieve a preset throttle opening degree set depending on a target amount of air for realizing a demand torque; and a throttle opening degree correcting section for correcting the preset throttle opening degree on the basis of the target air amount at fuel cut that stops supplying fuel to the internal combustion engine and an actual air amount measured by the air flow rate sensor (106), characterized in that the throttle opening degree correcting section corrects the preset throttle opening degree when a difference between the target air amount during fuel cut and the actual air amount measured by the air flow rate sensor (106) is equal to or larger than a preset value.The internal combustion engine control device according to claim 1, wherein the throttle opening degree correction section corrects the preset throttle opening degree by correcting a relationship between the preset throttle opening degree and an opening area based on the target air amount during fuel cut and the actual air amount measured by the air flow rate sensor (106).An internal combustion engine control apparatus for controlling an internal combustion engine including an air flow rate sensor (106) for measuring an amount of air represented as an actual amount of air, the air flowing into a cylinder (117), and a throttle valve (104) for adjusting the amount of air, the internal combustion engine control apparatus comprising: a throttle valve control portion for controlling a throttle opening degree of the throttle valve (104) to achieve a preset throttle opening degree set depending on a target amount of air for realizing a demand torque; A throttle opening degree correction section for correcting the preset throttle opening degree on the basis of the target air amount at a fuel cut that stops supplying fuel to the internal combustion engine and an actual air amount measured by the air flow rate sensor (106), characterized in that the throttle opening degree correction section corrects the preset throttle opening degree when a throttle opening degree of the throttle valve (104) is smaller than a sonic opening degree at which a speed of the air flowing through the throttle valve (104) becomes the sonic speed.The internal combustion engine control device according to claim 3, wherein a sonic opening degree at which a velocity of the air flowing through the throttle valve (104) is the sonic velocity is set in advance; and the throttle opening degree correction section corrects the set throttle opening degree in advance when a throttle opening degree of the throttle valve (104) is smaller than the sonic opening degree.The internal combustion engine control device according to claim 3, further comprising: a sonic speed determination section for determining a sonic opening degree at which a speed of the air flowing through the throttle valve (104) is the sonic speed set in advance based on a ratio of the pressures before and after the throttle valve (104), wherein the throttle opening degree correction section corrects the preset throttle opening degree when the sonic speed determination section determines that a sonic state is established.The internal combustion engine control device according to claim 3, wherein the throttle opening degree correction section corrects the preset throttle opening degree in a direction such that the throttle valve (104) is closed when an actual air amount measured by the air flow rate sensor (106) is larger than a preset value instead of the target air amount during the fuel cut.The internal combustion engine control device according to claim 3, wherein when exhaust gases of the internal combustion engine are recirculated to a position upstream of the throttle valve (104), even if a difference between the target air amount during fuel cut and an actual air amount measured by the air flow rate sensor (106) is equal to or larger than a preset value, the throttle cap opening degree correction section does not correct the preset throttle opening degree until the exhaust gases flowing through the throttle valve (104) are removed.The internal combustion engine control apparatus according to claim 7, wherein when the exhaust gases of the internal combustion engine are recirculated to the position upstream of the throttle valve (104), the throttle cap opening degree correction section corrects the throttle valve opening degree set in advance after the exhaust gases flowing through the throttle valve (104) are removed.The internal combustion engine control device according to claim 3, wherein the throttle opening degree correction section corrects the preset throttle opening degree on the basis of the target air amount during fuel cut and an actual air amount measured by the air flow rate sensor (106) when a vehicle including the internal combustion engine travels at vehicle speeds equal to or higher than a preset vehicle speed.

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