JP2010242693A - Control device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To calculate cylinder inflow air volume coincident with actual cylinder inflow air volume, when an operation state of an internal combustion engine assumes a largely changing state of the cylinder inflow air volume. <P>SOLUTION: The control device of the internal combustion engine controls operation of the internal combustion engine based on a calculation value of the cylinder inflow air volume, by calculating the volume of air sucked in a combustion chamber 25 in an intake stroke based on a model expression. An actual value of the cylinder inflow air volume when a predetermined time passes after starting a calculation of the cylinder inflow air volume, is calculated as a predictor of the cylinder inflow air volume when starting the calculation of the cylinder inflow air volume. A difference between this predictor and the actual value of the cylinder inflow air volume when starting the calculation of the cylinder inflow air volume, is calculated as a change predictor of the cylinder inflow air volume when stating the calculation of the cylinder inflow air volume. When this change predictor is larger than a predetermined change predictor, a calculation value of the cylinder inflow air volume is corrected in response to the change predictor of the cylinder inflow air volume. The operation of the internal combustion engine is controlled based on the corrected calculation value of the cylinder inflow air volume. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a control device for an internal combustion engine.

  A control device for an internal combustion engine is known that controls the amount of fuel supplied into the combustion chamber to an optimum amount in accordance with the amount of air taken into the combustion chamber during the intake stroke. In order to supply an optimal amount of fuel into the combustion chamber in such a control device, it is necessary to accurately know the amount of air taken into the combustion chamber during the intake stroke. In addition to supplying the optimum amount of fuel into the combustion chamber, it may be necessary to accurately know the amount of air taken into the combustion chamber during the intake stroke in order to control the operation of the internal combustion engine. .

  Patent Document 1 discloses means for accurately knowing the amount of air taken into the combustion chamber during the intake stroke. According to the means disclosed in Patent Document 1, the air drawn into the combustion chamber through the intake passage is sucked into the combustion chamber during the intake stroke using a model formula derived from the law of conservation of mass and the law of conservation of energy. The amount of air (hereinafter referred to as “in-cylinder inflow air amount”) is calculated. Here, since the model formula disclosed in Patent Document 1 is discretized, the calculation of the in-cylinder inflow air amount is performed at regular time intervals according to this model formula.

JP 2001-041095 A JP 2006-070881 A

  By the way, when the cylinder inflow air amount is calculated by calculation using a model formula as disclosed in Patent Document 1, it takes a certain time to calculate the cylinder inflow air amount. Therefore, when calculating the in-cylinder intake air amount using the model formula, at least the in-cylinder inflow air amount or the in-cylinder inflow air amount calculation at the time when the calculation of the in-cylinder inflow air amount is completed at least It is preferable to calculate the in-cylinder inflow air amount. However, as described above, when calculating the in-cylinder inflow air amount using the discretized model formula, the in-cylinder inflow air amount is calculated at a constant time interval, but is disclosed in Patent Document 1. According to the means, it is not assumed that the in-cylinder inflow air amount greatly increases or decreases during this fixed time interval, that is, that the in-cylinder inflow air amount significantly changes. For this reason, even if the in-cylinder inflow air amount is calculated using the discretized model equation when the operating state of the internal combustion engine is in a state where the in-cylinder inflow air amount changes significantly, the calculation of the in-cylinder inflow air amount is performed. Is completed, the actual in-cylinder inflow air amount has changed significantly compared to the actual in-cylinder inflow air amount when the calculation of the in-cylinder inflow air amount is started. It cannot be said that the air amount matches the actual in-cylinder inflow air amount.

  Therefore, an object of the present invention is to calculate the in-cylinder inflow air amount that matches the actual in-cylinder inflow air amount when the operating state of the internal combustion engine is in a state in which the in-cylinder inflow air amount changes significantly.

  According to the first aspect of the present invention, the air sucked into the combustion chamber is sucked into the combustion chamber during the intake stroke based on the in-cylinder inflow air amount calculation model equation derived using the law of conservation of mass and the law of conservation of energy. In a control device for an internal combustion engine that controls the operation of the internal combustion engine based on the calculated value of the in-cylinder inflow air amount, the actual combustion is performed during the intake stroke. When the amount of air sucked into the room is referred to as the actual value of the in-cylinder inflow air amount, the in-cylinder inflow air amount when a predetermined time has elapsed since the calculation of the in-cylinder inflow air amount was started. Is calculated as a predicted value of the cylinder inflow air amount at the start of calculation of the cylinder inflow air amount, and the predicted value of the cylinder inflow air amount and the cylinder inflow air amount at the start of calculation of the cylinder inflow air amount are calculated. The difference from the actual value of Calculated as the predicted change value of the inflow air amount, and when the predicted change value of the inflow amount of the cylinder is larger than the predicted change value of the inflow, the calculated value of the inflow amount of the cylinder And the operation of the internal combustion engine is controlled based on the corrected calculated value of the in-cylinder inflow air amount.

  According to the second invention, in the first invention, a throttle valve is disposed in the intake passage connected to the combustion chamber, and the opening degree of the throttle valve at the start of calculation of the in-cylinder inflow air amount and the When the difference between the opening of the throttle valve to be targeted at the start of calculation of the in-cylinder inflow air amount is larger than a predetermined opening difference, the predicted change in in-cylinder inflow air amount is the predetermined change. It is determined that the value is larger than the predicted value.

  According to a third aspect, in the second aspect, when the pressure in the intake passage downstream of the throttle valve is referred to as a throttle valve downstream pressure, the predetermined amount is determined after the calculation of the in-cylinder inflow air amount is started. The throttle valve downstream pressure when the specified time has elapsed is calculated as a predicted value of the throttle valve downstream pressure at the start of calculation of the in-cylinder inflow air amount, and the predicted value of the throttle valve downstream pressure and in-cylinder inflow air amount are calculated. The difference from the throttle valve downstream pressure at the start is calculated as the change amount of the throttle valve downstream pressure at the start of the calculation of the cylinder inflow air amount, and the change amount of the throttle valve downstream pressure is larger than the predetermined pressure change amount. When it is larger, it is determined that the change predicted value of the in-cylinder inflow air amount is larger than the predetermined change predicted value.

  According to a fourth aspect, in the second or third aspect, the pressure in the intake passage downstream of the throttle valve is referred to as throttle valve downstream pressure, and the flow rate of air passing through the throttle valve is defined as the throttle valve passing air flow rate. When the throttle valve downstream pressure is higher than a specific pressure, even if the throttle valve opening is constant, the higher the throttle valve downstream pressure, the smaller the throttle valve passing air flow rate, and the calculation of the in-cylinder inflow air amount. It is determined that the throttle valve downstream pressure becomes higher than the specific pressure or the throttle valve downstream pressure becomes higher in a region higher than the specific pressure after the predetermined time elapses after the start of Or when the throttle valve downstream pressure becomes lower than the specific pressure or the throttle valve downstream pressure becomes lower than the specific pressure. Change predicted value of the cylinder inflow air amount is determined to the higher than predetermined change predicted value when it is determined to be lower in the higher region than.

  According to a fifth aspect, in any one of the second to fourth aspects, the pressure in the intake passage downstream of the throttle valve is referred to as a throttle valve downstream pressure, and the flow rate of air passing through the throttle valve is determined as a throttle. When the throttle valve downstream pressure is higher than a specific pressure, the throttle valve passage air flow is smaller and the throttle valve passage air flow is smaller when the throttle valve downstream pressure is higher than a specific pressure. If the downstream pressure is constant, the larger the throttle valve opening, the larger the throttle valve passing air flow rate. The throttle valve opening, the throttle valve downstream pressure, and the throttle valve passing air flow rate at the start of calculating the in-cylinder inflow air amount Are referred to as the reference throttle opening, the reference throttle valve downstream pressure, and the reference throttle valve passage air flow rate, respectively. When the predetermined time has elapsed, the throttle valve opening is larger than the reference throttle opening, the throttle valve downstream pressure is higher than the reference throttle valve downstream pressure, and the predetermined time is The throttle valve downstream pressure when the predetermined time elapses is higher than the throttle valve downstream pressure at which the throttle valve passage air flow rate becomes equal to the reference throttle valve passage air flow rate at the opening degree of the throttle valve when the time has elapsed. Is determined to be larger than the predetermined change prediction value, and the change prediction value of the cylinder inflow air amount is determined from the predetermined change prediction value. Will be greatly reduced.

  According to a sixth aspect, in the first aspect, the throttle valve is disposed in the intake passage connected to the combustion chamber, and the pressure in the intake passage downstream of the throttle valve is referred to as throttle valve downstream pressure. Then, the throttle valve downstream pressure when the predetermined time has elapsed after the calculation of the in-cylinder inflow air amount is started is calculated as a predicted value of the throttle valve downstream pressure at the start of the in-cylinder inflow air amount calculation. Calculating a difference between the predicted value of the throttle valve downstream pressure and the throttle valve downstream pressure at the start of calculation of the cylinder inflow air amount as a change amount of the throttle valve downstream pressure at the start of calculation of the cylinder inflow air amount, When the change amount of the throttle valve downstream pressure is larger than the predetermined pressure change amount, it is determined that the change predicted value of the in-cylinder inflow air amount is larger than the predetermined change predicted value.

  According to a seventh aspect, in the first aspect, a throttle valve is disposed in the intake passage connected to the combustion chamber, and the pressure in the intake passage downstream of the throttle valve is referred to as the throttle valve downstream pressure, and When the flow rate of air passing through the throttle valve is referred to as a throttle valve passing air flow rate, when the throttle valve downstream pressure is higher than a specific pressure, the throttle valve downstream pressure is high even if the throttle valve opening is constant. The throttle valve passing air flow rate is so small that the throttle valve downstream pressure becomes higher than the specific pressure or the throttle valve after the predetermined time elapses after the calculation of the in-cylinder inflow air amount is started. When it is determined that the valve downstream pressure is higher in the region higher than the specific pressure, or the throttle valve downstream pressure exceeds the specific pressure. Or when it is determined that the pressure downstream of the throttle valve is low in the region where the pressure is higher than the specific pressure, it is determined that the predicted change value of the in-cylinder inflow air amount is larger than the predetermined predicted change value. .

  According to an eighth aspect, in the first aspect, a throttle valve is disposed in the intake passage connected to the combustion chamber, and the pressure in the intake passage downstream of the throttle valve is referred to as the throttle valve downstream pressure, and When the flow rate of air passing through the throttle valve is referred to as a throttle valve passing air flow rate, when the throttle valve downstream pressure is higher than a specific pressure, the throttle valve downstream pressure is high even if the throttle valve opening is constant. If the throttle valve passage air flow rate is smaller and the throttle valve downstream pressure is constant, the throttle valve passage air flow rate is larger as the throttle valve opening degree is larger, and the throttle valve opening amount at the start of calculation of the in-cylinder inflow air amount, Throttle valve downstream pressure and throttle valve passing air flow rate are respectively set as reference throttle opening, throttle valve downstream pressure, and reference. When it is referred to as the Lottle valve passage air flow rate, when the predetermined time has elapsed, the opening degree of the throttle valve is larger than the reference throttle opening degree, and the actual throttle downstream pressure is higher than the reference throttle valve downstream pressure. The predetermined time elapses from the throttle valve downstream pressure at which the throttle valve passage air flow rate becomes equal to the reference throttle valve passage air flow rate at the opening degree of the throttle valve when the predetermined time is high. When it is determined that the downstream pressure of the throttle valve is high, it is determined that the predicted change value of the cylinder inflow air amount is larger than the predetermined change prediction value and the predicted change value of the cylinder inflow air amount is It is determined that the value is greatly decreased from the predetermined change prediction value.

  According to a ninth invention, in the first invention, a throttle valve is disposed in an intake passage connected to the combustion chamber, and the cylinder inflow air amount calculation model equation is the amount of air passing through the throttle valve. It includes a throttle valve passage air flow rate calculation model formula for calculating the flow rate as a calculated value of the throttle valve passage air flow rate, and it is determined that the predicted change value of the in-cylinder inflow air amount is larger than the predetermined change predicted value. The cylinder inflow air amount calculation model equation is corrected by correcting the calculated value of the throttle valve passage air flow rate calculated by the throttle valve passage air flow rate calculation model equation according to the predicted change value of the cylinder inflow air amount. The calculated value of the in-cylinder inflow air amount calculated by the above is corrected according to the predicted change value of the in-cylinder inflow air amount.

  According to a tenth aspect, in the ninth aspect, when the flow rate of air passing through the throttle valve is referred to as a throttle valve passage air flow rate, the predetermined amount is determined after the calculation of the in-cylinder inflow air amount is started. The throttle valve passage air flow rate is calculated as a predicted value of the throttle valve passage air flow rate at the start of calculation of the cylinder inflow air amount when the predetermined time has elapsed, and the predicted value of the throttle valve passage air flow rate and the cylinder inflow air amount are calculated. Is calculated as a predicted change value of the throttle valve passing air flow rate at the start of calculation of the in-cylinder inflow air amount, and the predicted change value of in-cylinder inflow air amount is calculated in advance. By correcting the calculated value of the throttle valve passing air flow rate according to the predicted change value of the throttle valve passing air flow rate when it is determined that the predicted value is larger than the predetermined change predicted value. Calculated value of the throttle valve passing air flow rate is corrected according to the change in the predicted value of the cylinder inflow air quantity.

  According to the eleventh aspect, in the tenth aspect, when the pressure in the intake passage downstream of the throttle valve is referred to as the throttle valve downstream pressure, the predetermined amount is determined after the calculation of the in-cylinder inflow air amount is started. The throttle valve downstream pressure when the predetermined time has elapsed is calculated as a predicted value of the throttle valve downstream pressure at the start of the in-cylinder inflow air amount calculation process, and the predicted value of the throttle valve downstream pressure and the in-cylinder inflow air amount are calculated. The difference from the throttle valve downstream pressure at the start is calculated as the change amount of the throttle valve downstream pressure at the start of calculation of the cylinder inflow air amount, and the change prediction value of the cylinder inflow air amount is the predetermined change prediction value. When the calculated value of the throttle valve passage air flow rate is corrected, the calculated value of the throttle valve passage air flow rate is corrected according to the amount of change in the throttle valve downstream pressure. Value is corrected according to the change predicted value of the throttle valve passage air flow rate.

  According to the twelfth aspect, in the tenth or eleventh aspect, the opening degree of the throttle valve when the predetermined time has elapsed since the calculation of the in-cylinder inflow air quantity is started is determined. Is calculated as the predicted value of the throttle opening at the start of the calculation of the throttle, and the difference between the predicted value of the throttle opening and the opening of the throttle valve at the start of the calculation of the inflow of cylinder air is calculated. Is calculated as a predicted change value of the throttle opening, and when it is determined that the predicted change value of the in-cylinder inflow air amount is larger than the predetermined predicted change value, the calculated value of the throttle valve passage air flow rate is calculated. The calculated value of the throttle valve passing air flow rate is corrected according to the predicted change value of the throttle valve passing air flow rate by correcting according to the predicted change value of the degree.

  According to the thirteenth invention, in any one of the first to twelfth inventions, when it is determined that the change predicted value of the in-cylinder inflow air amount is larger than the predetermined change predicted value. When it is determined that the change predicted value of the cylinder inflow air amount is larger than the predetermined change prediction value, the calculated value of the cylinder inflow air amount is corrected so as to increase. Is determined to be larger than the predetermined change prediction value, and it is determined that the change prediction value of the in-cylinder inflow air amount is greatly decreased from the predetermined change prediction value. Sometimes the correction is made so that the calculated value of the in-cylinder inflow air amount becomes small.

  According to the fourteenth invention, in any one of the ninth to thirteenth inventions, the opening of the throttle valve at the start of calculation of the cylinder inflow air amount and the target at the start of calculation of the cylinder inflow air amount. When the difference between the opening degree of the throttle valve to be increased is larger than a predetermined opening degree difference, it is determined that the predicted change value of the in-cylinder inflow air amount is larger than the predetermined predicted change value.

  According to the fifteenth aspect of the invention, in any one of the ninth to fourteenth aspects of the invention, when the pressure in the intake passage downstream of the throttle valve is referred to as throttle valve downstream pressure, the calculation of the cylinder inflow air amount is performed. The throttle valve downstream pressure when the predetermined time has elapsed from the start is calculated as a predicted value of the throttle valve downstream pressure at the start of calculation of the in-cylinder inflow air amount. The difference from the throttle valve downstream pressure at the start of calculation of the inflow air amount is calculated as the change amount of the throttle valve downstream pressure at the start of calculation of the inflow of the cylinder, and the change amount of the throttle valve downstream pressure is determined in advance. When the pressure change amount is larger than the predetermined change amount, it is determined that the predicted change value of the in-cylinder inflow air amount is larger than the predetermined change prediction value.

  According to the sixteenth invention, in any one of the ninth to fifteenth inventions, the pressure in the intake passage downstream of the throttle valve is referred to as the throttle valve downstream pressure, and the flow rate of the air passing through the throttle valve is throttled. When the throttle valve downstream pressure is higher than a specific pressure, the throttle valve passage air flow is smaller when the throttle valve downstream pressure is higher than the specific pressure. The throttle valve downstream pressure becomes higher than the specific pressure or the throttle valve downstream pressure is higher than the specific pressure until the predetermined time elapses after the calculation of the inflow air amount is started. When it is determined that the pressure is high in the region, or the throttle valve downstream pressure becomes lower than the specific pressure or the throttle valve downstream pressure The specific changes predicted value of the cylinder inflow air quantity when it is judged to be lower in the region higher than the pressure is determined to the higher than predetermined change predicted value.

  According to a seventeenth aspect, in any one of the ninth to sixteenth aspects, a pressure in the intake passage downstream of the throttle valve is referred to as a throttle valve downstream pressure, and a flow rate of air passing through the throttle valve is determined as a throttle. When the throttle valve downstream pressure is higher than a specific pressure, the throttle valve passage air flow rate decreases as the throttle valve downstream pressure increases and the throttle valve downstream pressure is constant. If the downstream pressure is constant, the larger the throttle valve opening, the more the throttle valve passing air flow rate. The throttle valve opening, the throttle valve downstream pressure, and the throttle valve passing air flow rate at the start of calculating the in-cylinder inflow amount Are referred to as the reference throttle opening, the reference throttle valve downstream pressure, and the reference throttle valve passage air flow rate, respectively. When the predetermined time has elapsed, the throttle valve opening is larger than the reference throttle opening, the throttle valve downstream pressure is higher than the reference throttle valve downstream pressure, and the predetermined time is The throttle valve downstream pressure when the predetermined time elapses is higher than the throttle valve downstream pressure at which the throttle valve passage air flow rate becomes equal to the reference throttle valve passage air flow rate at the opening degree of the throttle valve when the time has elapsed. Is determined to be greater than the predetermined change prediction value and the change prediction value of the cylinder inflow air amount is the predetermined change prediction value. It is judged that it will decrease greatly.

  According to an eighteenth aspect, in any one of the first to seventeenth aspects, the calculation of the in-cylinder inflow air amount is executed at a predetermined time interval, and the predetermined time is the predetermined time. Equal to a defined time interval.

  According to a nineteenth aspect of the present invention, in any one of the first to seventeenth aspects of the present invention, the calculation is performed by calculating the in-cylinder inflow air amount after the predetermined time is started. The calculated value of the in-cylinder inflow air amount is equal to the time until it is used for controlling the operation of the internal combustion engine.

  According to a twentieth invention, in any one of the first to nineteenth inventions, the internal combustion engine includes a supercharger, and the in-cylinder inflow air amount calculation model formula passes through the compressor of the supercharger. It includes a compressor passing air flow rate calculation model formula that calculates the air flow rate as a calculated value of the compressor passing air flow rate, and it is determined that the change predicted value of the in-cylinder inflow air amount is larger than the predetermined change predicted value. When the calculated value of the compressor passing air flow rate calculated by the compressor passing air flow rate calculating model equation is corrected according to the predicted change value of the inflowing cylinder air amount, The calculated value of the in-cylinder inflow air amount is corrected in accordance with the predicted change value of the in-cylinder inflow air amount.

  As described above, according to the first to twentieth inventions, when the actual change amount of the in-cylinder inflow air amount after the calculation of the in-cylinder inflow air amount is started, the change amount of the in-cylinder inflow air amount is changed. Accordingly, the calculated value of the in-cylinder inflow air amount is corrected, so that the in-cylinder inflow air amount that matches the actual in-cylinder inflow air amount is calculated, or at least compared with the calculated value of the in-cylinder inflow air amount that is not corrected. An in-cylinder inflow air amount close to the actual in-cylinder inflow air amount is calculated.

  According to the nineteenth aspect of the invention, the calculated value of the in-cylinder inflow air amount is corrected according to the amount of change in the in-cylinder inflow air amount until it is used for controlling the operation of the internal combustion engine. The in-cylinder inflow air amount that matches the actual in-cylinder inflow air amount when used for the control of the cylinder is calculated or at least compared with the calculated value of the in-cylinder inflow air amount that is not corrected. An in-cylinder inflow air amount close to is calculated.

  According to the twentieth aspect of the present invention, in an internal combustion engine equipped with a supercharger, the in-cylinder inflow air amount that corresponds to the actual change in the in-cylinder inflow air flow rate is calculated or at least not corrected. The in-cylinder inflow air amount that is closer to the actual in-cylinder inflow air amount than the calculated value is calculated.

It is the figure which showed the spark ignition type internal combustion engine to which the control apparatus of this invention is applied. It is the functional block diagram which showed the function of the model of this invention. It is the figure which showed the map which prescribes | regulates the relationship between accelerator pedal depression amount Accp and target throttle opening (theta) t. FIG. 6 is a diagram illustrating a map that defines a relationship between a difference Δθ between a target throttle opening θt and a predicted throttle opening θe and a function f (θt, θe). It is the figure which showed the map which prescribes | regulates the relationship between throttle opening (theta) and product C ((theta)) * A ((theta)). It is the figure which showed the map which prescribes | regulates the relationship between pressure ratio Pm / Pa, throttle opening (theta), and value (Pm / Pa). It is the figure which showed the map which prescribes | regulates the relationship between the engine speed NE, the intake valve opening / closing timing VT, and the proportionality coefficient c. It is the figure which showed the map which prescribes | regulates the relationship between the engine speed NE, the intake valve opening / closing timing VT, and the value d. It is the figure which showed the relationship between pressure ratio Pm / Pa and throttle valve passage air flow rate mt. It is the figure which showed the relationship between pressure ratio Pm / Pa and throttle valve passage air flow rate mt. It is the figure which showed the relationship between the intake pipe pressure Pm and value (Pm / Pa). It is the figure which showed the map which prescribes | regulates the relationship between the intake pipe pressure Pm, throttle opening (theta), and value (Pm / Pa). It is the figure which showed an example of the flowchart which performs the calculation according to the electronic control throttle valve model M1. It is the figure which showed an example of the flowchart which performs the calculation according to the throttle model M2, the intake valve model M3, the intake pipe model M4, and the intake valve model M5. It is the figure which showed an example of the flowchart which performs the calculation according to the throttle model M2, the intake valve model M3, the intake pipe model M4, and the intake valve model M5. It is the figure which showed an example of the flowchart which performs the calculation according to the throttle model M2, the intake valve model M3, the intake pipe model M4, and the intake valve model M5. 1 is a diagram showing a spark ignition type internal combustion engine to which a control device of the present invention is applied, which is equipped with a supercharger. It is the functional block diagram which showed the function of the model of this invention. It is the figure which showed the map which prescribes | regulates the relationship between pressure ratio Pm / Pi, throttle opening (theta), and the value (Pm / Pi). It is the figure which showed the relationship between pressure ratio Pi / Pa, compressor rotation speed NC, and compressor outflow air flow rate mcm. It is the figure which showed the map which prescribes | regulates the relationship between pressure ratio Pm / Pi, compressor rotation speed NC, and compressor outflow air flow rate mcm. It is the figure which showed the relationship between compressor outflow air flow rate mcm, compressor rotation speed NC, and compressor efficiency (eta). It is the figure which showed the map which prescribes | regulates the relationship between compressor outflow air flow rate mcm, compressor rotation speed NC, and compressor efficiency (eta). It is the figure which showed the relationship between the intercooler pressure Pi, the compressor rotation speed NC, and the compressor outflow air flow rate mcm. It is the figure which showed the map which prescribes | regulates the relationship between the intercooler pressure Pi, the compressor rotation speed NC, and the compressor outflow air flow rate mcm. It is the figure which showed the relationship between pressure ratio Pm / Pi and throttle valve passage air flow rate mt. It is a figure showing an example of a flowchart which performs calculation according to throttle model M2, intake valve model M3, intake pipe model M4, intake valve model M5, compressor model M6, and intercooler model M7. It is a figure showing an example of a flowchart which performs calculation according to throttle model M2, intake valve model M3, intake pipe model M4, intake valve model M5, compressor model M6, and intercooler model M7. It is a figure showing an example of a flowchart which performs calculation according to throttle model M2, intake valve model M3, intake pipe model M4, intake valve model M5, compressor model M6, and intercooler model M7. It is the figure which showed the relationship between the intercooler pressure Pi, the compressor rotation speed NC, and the compressor outflow air flow rate mcm.

  Embodiments of an internal combustion engine to which a control device of the present invention is applied will be described below with reference to the drawings. FIG. 1 shows a spark ignition type internal combustion engine to which the control device of the present invention is applied. The internal combustion engine shown in FIG. 1 is a multi-cylinder internal combustion engine having a plurality of combustion chambers, that is, a plurality of cylinders. FIG. 1 shows the configuration of only one specific cylinder, but the rest The cylinder has the same configuration.

  An internal combustion engine 10 shown in FIG. 1 includes a cylinder block portion 20 including a cylinder block, a cylinder block lower case, an oil pan, and the like, a cylinder head portion 30 fixed on the cylinder block portion 20, and a cylinder block portion 20. An intake system 40 for supplying an air-fuel mixture composed of fuel and air and an exhaust system 50 for exhausting exhaust gas from the cylinder block 20 to the outside are provided.

  The cylinder block unit 20 includes a cylinder 21, a piston 22, a connecting rod 23, and a crankshaft 24. The piston 22 reciprocates in the cylinder 21, and the reciprocating motion of the piston 22 is transmitted to the crankshaft 24 through the connecting rod 23, whereby the crankshaft 24 is rotated. A combustion chamber 25 is formed by the inner wall surface of the cylinder 21, the upper wall surface of the piston 22, and the lower wall surface of the cylinder head portion 30.

  The cylinder head portion 30 includes an intake port 31 communicating with the combustion chamber 25, an intake valve 32 that opens and closes the intake port 31, an intake camshaft (not shown) that drives the intake valve 32, and the intake camshaft. And a variable intake timing device 33 having an actuator 33a capable of continuously changing the phase angle. The cylinder head portion 30 includes an exhaust port 34 communicating with the combustion chamber 25, an exhaust valve 35 that opens and closes the exhaust port 34, and an exhaust camshaft 36 that drives the exhaust valve 35. The cylinder head 30 further includes an ignition plug 37 that ignites the fuel in the combustion chamber 25, an igniter 38 that includes an ignition coil that applies a high voltage to the ignition plug 37, and a fuel injection that injects fuel into the intake port 31. And a valve 39.

  The intake system 40 includes an intake branch pipe 41 connected to the intake port 31, a surge tank 42 connected to the intake branch pipe 41, and an intake duct 43 connected to the surge tank 42. The intake duct 43, the intake port 31, the intake branch pipe 41, and the surge tank 42 constitute an intake passage. Further, the intake system 40 has an air filter 44, a throttle valve 46, and a throttle valve driving actuator 46a for driving the throttle valve 46 in order from the upstream end of the intake duct 43 toward the downstream (that is, toward the surge tank 42). Is provided in the intake duct 43. The intake duct 43 is provided with a pressure sensor 61 for detecting the pressure of the air flowing through the intake duct 43 and a temperature sensor 62 for detecting the temperature of the air flowing through the intake duct 43.

  The throttle valve 46 is rotatably attached to the intake duct 43, and its opening degree is adjusted by being driven by a throttle valve driving actuator 46a. That is, the throttle valve 46 can adjust the flow passage area of the intake duct 43. The throttle valve driving actuator 46a is a DC motor, and the actual opening of the throttle valve 46 (hereinafter referred to as “throttle opening”) according to a drive signal output in accordance with an electronically controlled throttle valve logic executed by an electric control unit 70 described later. The throttle valve 46 is driven so that the target throttle opening is reached.

  The exhaust system 50 includes an exhaust pipe 51 including an exhaust branch pipe connected to the exhaust port 34, and a three-way catalyst device 52 disposed in the exhaust pipe 51. The exhaust pipe 51, the exhaust port 34, and the three-way catalyst device constitute an exhaust passage.

  The internal combustion engine 10 includes a cam position sensor 64 that detects the phase angle of the intake camshaft, a crank position sensor 65 that detects the phase angle of the crankshaft 24, an accelerator opening sensor 66 that detects the amount of depression of the accelerator pedal, And an electric control device 70. The accelerator opening sensor 66 functions as an operating state acquisition unit A2 that acquires parameters relating to the operating state of the internal combustion engine 10.

  The pressure sensor 61 is attached to the intake duct 43 between the air filter 44 and the throttle valve 46. The pressure sensor 61 detects the pressure of air in the intake duct 43 and detects the pressure of air in the intake passage upstream of the throttle valve 46 (hereinafter referred to as “pressure sensor 61”). A signal indicating "intake pressure") is output. On the other hand, the temperature sensor 62 is attached to the intake duct 43 between the air filter 44 and the throttle valve 46 and detects the temperature of the air in the intake duct 43 to detect the temperature of the air in the intake passage upstream of the throttle valve 46. (Hereinafter referred to as “intake air temperature”) is output. The cam position sensor 64 generates a pulse signal every time the intake camshaft rotates 90 ° (that is, every time the crankshaft 24 rotates 180 °). On the other hand, the crank position sensor 65 generates a narrow pulse signal every time the crankshaft 24 rotates 10 ° and generates a wide pulse signal every time the crankshaft 24 rotates 360 °. The rotational speed of the internal combustion engine (hereinafter referred to as “engine speed”) can be calculated based on the pulse signal generated by the crank position sensor 65. The accelerator opening sensor 66 detects the depression amount of the accelerator pedal 67 operated by the driver, and outputs a signal representing the depression amount of the accelerator pedal.

  The electric control device 70 is a microcomputer, which stores in advance a CPU (microprocessor) 71 connected to each other by a bidirectional bus, a program executed by the CPU 71, a map (including a lookup table), a constant, and the like. A ROM (Read Only Memory) 72, a RAM (Random Access Memory) 73 in which the CPU 71 temporarily stores data as necessary, and stores data when the power is turned on, and the stored power It consists of a backup RAM 54 that retains data while it is shut off, and an interface 75 that includes an AD converter. The interface 75 is connected to the pressure sensor 61 and the temperature sensor 62, supplies signals from the pressure sensor 61 and the temperature sensor 62 to the CPU 71, and in response to an instruction from the CPU 71, the actuator 33a, the igniter 38, Drive signals are output to the fuel injection valve 39 and the throttle valve drive actuator 46a.

  Next, an outline of a method for calculating the amount of air taken into the combustion chamber during the intake stroke (hereinafter referred to as “in-cylinder inflow air amount”) in the internal combustion engine configured as described above will be described.

  In the internal combustion engine 10, the target air-fuel ratio is set as the air-fuel ratio of the air-fuel mixture formed in the combustion chamber 25 in accordance with the operation state of the internal combustion engine (hereinafter referred to as “engine operation state”). On the other hand, in the internal combustion engine 10, the fuel injection valve 39 is disposed upstream of the intake valve 32. Therefore, in order to supply the fuel into the combustion chamber 25 and form the air-fuel mixture with the target air-fuel ratio in the combustion chamber 25, the fuel injection valve 39 is reached before the intake stroke is completed, that is, until the intake valve 32 is closed. From this, the amount of fuel to be injected (hereinafter referred to as “fuel injection amount”) is determined, and fuel must be injected from the fuel injection valve 39. Here, in order to determine the fuel injection amount that forms the air-fuel mixture of the target air-fuel ratio in the combustion chamber 25, the in-cylinder inflow air when the intake valve 32 is closed before the fuel is injected from the fuel injection valve 39. The quantity must be calculated. Therefore, in this embodiment, the in-cylinder inflow air amount is calculated by the in-cylinder inflow air amount calculation device until the fuel is injected from the fuel injection valve 39 as follows.

  In other words, the in-cylinder inflow air amount calculation device of the present embodiment uses a plurality of physical models derived using physical laws such as mass conservation law, energy conservation law, and momentum conservation law regarding the air in the intake passage. The in-cylinder inflow air amount is calculated. That is, as shown in the functional block diagram of FIG. 2, the in-cylinder inflow air amount calculation device of this embodiment includes an electronically controlled throttle valve model M1, a throttle model M2, an intake valve model M3, and an intake pipe model M4. The in-cylinder inflow air amount is calculated using the intake valve model M5.

  Briefly explaining the function of each model, the electronically controlled throttle valve model M1 cooperates with the electronically controlled throttle valve logic A1 to set a target throttle opening (hereinafter referred to as "target throttle opening") based on the accelerator pedal depression amount. ) And a drive signal is output to the throttle valve driving actuator 46a so that the throttle opening becomes the target throttle opening, and a predicted value of the actual throttle opening is calculated. The throttle model M2 is a model for calculating the flow rate of air passing through the throttle valve 46 (hereinafter referred to as “throttle valve passing air flow rate”). The intake valve model M3 passes through the intake valve 32 and flows into the combustion chamber 25. The intake pipe model M4 is a model for calculating the flow rate of air to be discharged (hereinafter referred to as “intake valve passage air flow rate”). The intake pipe model M4 is a pressure in the intake passage downstream of the throttle valve 46 (hereinafter referred to as “intake pipe pressure”) and the throttle valve 46. This is a model for calculating the temperature in the downstream intake passage (hereinafter referred to as “intake pipe temperature”), and the intake valve model M5 is a model for calculating the in-cylinder inflow air amount.

  If the model expression of each model can be expressed by a generalized mathematical expression such as y = f (x) (hereinafter referred to as “general expression”), a variable is used to obtain a value y at a certain time before the current time. It is necessary to use a value at a certain time earlier than the current time as x. That is, when the value to be obtained by the general formula is a value at a certain time point before the present time, it is necessary to use a value at a certain time point before the present time as a variable used in the general formula. Here, as described above, the in-cylinder inflow air amount to be obtained by the in-cylinder inflow air amount calculation device of the present embodiment is the time when calculation processing by the in-cylinder inflow air amount calculation device is started, that is, before the current time. This is the amount of in-cylinder air flowing in at the time.

  Therefore, in the calculation process according to the throttle model M2 using the throttle opening, the intake pipe pressure, the intake pipe temperature, and the intake pressure as variables, the calculation process according to the throttle model M2 is executed, that is, before the current time. It is necessary to use the throttle opening, intake pipe pressure, intake pipe temperature, and intake pressure at a certain point in time. Here, if the period from the present time to a certain time point is relatively short, the intake pressure does not change significantly within the relatively short period. Therefore, in the present embodiment, the current intake pressure is used in the calculation process according to the throttle model M2. On the other hand, the throttle opening, the intake pipe pressure, and the intake pipe temperature may change significantly within this relatively short period even if the period from the present time to a certain time point is relatively short. Accordingly, in the present embodiment, the throttle opening, the intake pipe pressure, and the intake pipe temperature at a certain time earlier than the current time are used in the calculation process according to the throttle model M2.

  Similarly, an intake valve model M3, an intake pipe model M4 that uses intake pipe pressure, intake pipe temperature, intake air temperature, engine speed, and intake valve 32 opening / closing timing (hereinafter referred to as “intake valve opening / closing timing”) as variables, and Also in the calculation process according to the intake valve model M5, the intake pipe pressure, the intake pipe temperature, the intake air temperature, the engine speed, and the intake valve at the execution time of the calculation process according to these models, that is, at a certain time before the present time. It is necessary to use opening and closing timing. If the period from the present time to a certain time point is relatively short, the intake air temperature, the engine speed, and the intake valve opening / closing timing VT do not change significantly within this relatively short period. Therefore, in the present embodiment, the current intake air temperature, engine speed, and intake valve opening / closing timing are used in the calculation processing according to the intake valve model M3, the intake pipe model M4, and the intake valve model M5. On the other hand, the intake pipe pressure and the intake pipe temperature may change significantly within a relatively short period even if the period from the present time to a certain time point is relatively short. Therefore, in the present embodiment, the intake pipe pressure and the intake pipe temperature at a certain time before the current time are respectively used in the calculation processing according to the intake valve model M3, the intake pipe model M4, and the intake valve model M5.

  Thus, in the present embodiment, when the time point at which the calculation processing according to each model M2 to M5 is started is the current time point, the throttle opening, intake pipe pressure, intake or temperature, intake air temperature at a certain time earlier than the current time point The in-cylinder inflow air amount is calculated on the basis of the pressure, the intake air temperature, the engine speed, and the intake valve opening / closing timing. It is the amount of inflow air.

  Next, the details of the calculation method of the in-cylinder inflow air amount in the control device for the internal combustion engine shown in FIG. 1 will be described together with the details of each model.

  First, the electronic control throttle valve model M1 will be described. The electronically controlled throttle valve model M1 is executed at predetermined time intervals ΔT1 (hereinafter referred to as “predetermined time interval ΔT1”, for example, 2 ms). The electronically controlled throttle valve model M1 sets the target throttle opening based on the accelerator pedal depression amount in cooperation with the electronically controlled throttle valve logic A1, and drives the throttle valve so that the throttle opening becomes the target throttle opening. This is a model that outputs a drive signal to the actuator 46a and calculates a predicted value of the actual throttle opening.

  That is, there is a certain relationship as shown in FIG. 3 between the accelerator pedal depression amount Accp and the target throttle opening degree θt. Therefore, in the present embodiment, a map Ma that defines the relationship between the accelerator pedal depression amount Accp and the target throttle opening is stored in advance in the ROM 72 in the form as shown in FIG. Then, the electronic control throttle valve logic A1 sets the actual accelerator pedal depression amount Accp detected by the accelerator opening sensor 66 at the time of execution of the calculation according to the current electronic control throttle valve model M1 (hereinafter referred to as “model calculation time”). Based on the map Ma, the target throttle opening degree θt is obtained. Then, the electronically controlled throttle valve logic A1 sets the target throttle opening θt thus obtained as a target after TD for a predetermined time (hereinafter referred to as “predetermined delay time”, for example, 64 ms) from the time of the current model calculation. Set as throttle opening. Further, the electronically controlled throttle valve logic A1 has a throttle valve so that the throttle opening becomes the target throttle opening at the time of the current model calculation, that is, the target throttle opening set by the electronically controlled throttle valve logic A1 before the predetermined delay time TD. A drive signal is output to the drive actuator 46a.

Incidentally, the operation of the throttle valve driving actuator 46a is accompanied by a certain delay, and the throttle valve 46 has inertia. For this reason, even if a drive signal is output from the electronically controlled throttle valve logic A1 to the throttle valve driving actuator 46a, the throttle opening reaches the target throttle opening with a certain delay. Therefore, the electronically controlled throttle valve model M1 calculates the predicted value of the actual throttle opening after the predetermined delay time TD based on the following equation 1 as the predicted throttle opening θe and stores or stores it in the ROM 53.
θe (i) = θe (i-1) + ΔT1 · f (θt (i), θe (i-1)) (1)

  In the above equation 1, θe (i) is a predicted throttle opening after a predetermined delay time TD to be calculated by execution of calculation according to the current electronic control throttle valve model M1 (hereinafter referred to as “model calculation”). θe (i−1) is a predicted throttle opening calculated by the previous model calculation (that is, calculation according to the electronically controlled throttle valve model M1 executed before the predetermined time interval ΔT1), and θt (i) is The target throttle opening after a predetermined delay time TD set by the current model calculation, and ΔT1 is the predetermined time interval, that is, the time interval at which the model calculation is performed. As shown in FIG. 4, the function f (θt, θe) has a larger value as the difference Δθ between the target throttle opening θt and the predicted throttle opening θe increases, that is, a function that monotonously increases with respect to the difference Δθ. It is.

  Thus, according to the electronically controlled throttle valve model M1, the target throttle opening θt is obtained by the electronically controlled throttle valve logic A1, and the target throttle opening when the obtained target throttle opening is a predetermined delay time TD ahead of the present time. The drive signal is output to the throttle valve drive actuator 46a so that the current actual throttle opening becomes the target throttle opening set as the current target throttle opening before the predetermined delay time TD. At the same time, the actual throttle opening at the predetermined delay time TD ahead of the current time is calculated as the predicted throttle opening θe.

  When there is no delay in the operation of the throttle valve driving actuator 46a and the inertia of the throttle valve 46 can be ignored, the target throttle opening θt is predicted as it is instead of calculating the predicted throttle opening θe by the above equation 1. The throttle opening degree θe may be used.

  Next, the throttle model M2 will be described. Since a method for deriving a model expression representing the throttle model M2 is well known (see, for example, Japanese Patent Application Laid-Open No. 2001-041095 and Japanese Patent Application Laid-Open No. 2003-184613), detailed description of the method for deriving the throttle model M2 is omitted. . Further, the calculation according to the throttle model M2, the intake valve model M3, the intake pipe model M4, and the intake valve model M5 described below is performed as a series of calculations at a predetermined time interval ΔT2 (hereinafter referred to as the predetermined time interval ΔT1). It is called every “predetermined time interval ΔT2”, for example, 8 ms). Of course, the predetermined time interval ΔT2 and the predetermined time interval ΔT1 may be equal.

The throttle model M2 is a throttle valve passing air flow rate based on the following model equation 2 and model equation 3 derived by using physical laws such as mass conservation law, energy conservation law, momentum conservation law, and gas equation of state. That is, this is a model for calculating the flow rate of air passing through the throttle valve 46.

  In the above model formula 2 and model formula 3, mt is the throttle valve passing air flow rate to be calculated by the calculation according to the current throttle model M2 (hereinafter referred to as “model calculation”), and θ is the throttle opening, In the present embodiment, the predicted throttle opening θe is C (θ) is a flow coefficient corresponding to the throttle opening θ, and A (θ) is a throttle flow path area corresponding to the throttle opening θ, that is, the intake passage. Of the flow paths, the area of the flow path that is not blocked by the throttle valve 46 and through which air can flow, Pa is the intake pressure, that is, the pressure in the intake passage upstream of the throttle valve 46, and Ta is the intake air This is the temperature, that is, the temperature in the intake passage upstream of the throttle valve 46, and Pm is the intake air calculated by calculation (details will be described later) according to the intake pipe model M4. Pressure, i.e. the pressure of the throttle valve 46 in the intake passage downstream of. R is a gas constant, and κ is a specific heat ratio of air. In this embodiment, κ is a constant value.

  Further, the product (= C (θ) · A (θ)) of the flow coefficient C (θ) and the throttle flow path area A (θ) in the above-described model formula 2 is obtained in advance by experiments or the like as a value based on the throttle opening. I can keep it. Therefore, in this embodiment, a map Mca that defines the relationship between the throttle opening θ and the product C (θ) · A (θ) is obtained and stored in advance in the ROM 72 in the form shown in FIG. . The throttle model M2 obtains the product C (θ) · A (θ) from the map Mca based on the predicted throttle opening θe.

  Further, the value Φ (Pm / Pa) of the above model equation 2 is also previously determined by experiments or the like as a value based on the ratio of the intake pipe pressure Pm to the intake pressure Pa (hereinafter referred to as “pressure ratio”) Pm / Pa and the throttle opening θ. You can ask for it. Therefore, in this embodiment, a map MΦ defining the relationship among the pressure ratio Pm / Pa, the throttle opening θ, and the value Φ (Pm / Pa) is obtained and stored in advance in the ROM 72 in the form shown in FIG. Keep it. The throttle model M2 obtains the value Φ (Pm / Pa) from the map MΦ based on the pressure ratio Pm / Pa and the predicted throttle opening θe.

  Next, the intake valve model M3 will be described. Since a method for deriving a model expression representing the intake valve model M3 is well known (see, for example, Japanese Patent Application Laid-Open No. 2001-041095 and Japanese Patent Application Laid-Open No. 2003-184613), a detailed description of a method for deriving the intake valve model M3 is given below. Omitted.

The intake valve model M3 is a model for calculating the in-cylinder inflow air flow rate, that is, the flow rate of air flowing into the combustion chamber 25 through the intake valve 32 based on the following model equation 4 derived using empirical rules. It is.
mc = (Ta / Tm) · (c · Pm−d) (4)

  In the above model equation 4, mc is the in-cylinder inflow air flow to be calculated by the calculation according to the current intake valve model M3 (hereinafter referred to as “model calculation”), and Ta is the intake air temperature, that is, upstream of the throttle valve 46. , Tm is the intake pipe temperature calculated by calculation (details will be described later) according to the intake pipe model M4, that is, the temperature in the intake passage downstream of the throttle valve 46, and Pm is the intake pipe temperature. The intake pipe pressure calculated by calculation according to the model M4 (details will be described later), that is, the pressure in the intake passage downstream of the throttle valve 46, and c is a proportional coefficient corresponding to the engine speed and the intake valve opening / closing timing. D is a value corresponding to the amount of burned gas remaining in the combustion chamber 25 without being discharged from the combustion chamber 25 to the exhaust passage in the exhaust stroke, and the engine speed and intake valve opening. Is a value corresponding to the timing.

  In the model formula 4, the intake pipe pressure Pm is used as a variable. However, in order to calculate the in-cylinder inflow air flow rate, the pressure in the combustion chamber 25 in the intake stroke (hereinafter referred to as “in-cylinder pressure”) is essentially calculated. Should be used. However, the in-cylinder pressure in the intake stroke can be regarded as equal to the pressure in the intake passage upstream of the intake valve 32, that is, the intake pipe pressure. Therefore, in the present embodiment, the intake pipe pressure Pm is used as a variable instead of the in-cylinder pressure in the intake valve model M3.

  Further, the proportional coefficient c can be obtained in advance by experiments or the like as a value based on the engine speed and the intake valve opening / closing timing. Therefore, in this embodiment, a map Mc that defines the relationship among the engine speed NE, the intake valve opening / closing timing VT, and the proportional coefficient c is obtained and stored in advance in the ROM 72 in the form shown in FIG. The intake valve model M3 obtains the proportional coefficient c from the map Mc based on the engine speed NE and the intake valve opening / closing timing VT.

  Similarly, the value d can be obtained in advance by experiments or the like as a value based on the engine speed and the intake valve opening / closing timing. Therefore, in this embodiment, a map Md that defines the relationship among the engine speed NE, the intake valve opening / closing timing VT, and the value d is obtained and stored in advance in the ROM 72 in the form shown in FIG. The intake valve model M3 obtains a value d from the map Md based on the engine speed NE and the intake valve opening / closing timing VT.

  Next, the intake pipe model M4 will be described. Since a method for deriving a model expression representing the intake pipe model M4 is well known (see, for example, Japanese Patent Application Laid-Open No. 2001-041095 and Japanese Patent Application Laid-Open No. 2003-184613), a detailed description of a method for deriving the intake pipe model M4 is provided. Omitted.

The intake pipe model M4 is a model for calculating the intake pipe pressure and the intake pipe temperature based on the following model expression 5 and model expression 6 derived by using the mass conservation law and the energy conservation law.
d (Pm / Tm) / dt = (R / Vm) · (mt−mc) (5)
dPm / dt = κ · (R / Vm) · (mt · Ta-mc · Tm) (6)

  In the above model equations 4 and 5, Pm is the intake pipe pressure to be calculated by the current model calculation, Tm is the intake pipe temperature to be calculated by the current model calculation, and R is the gas constant. , Vm is the volume of the intake passage between the throttle valve 46 and the intake valve 32, mt is the air flow rate through the throttle valve calculated by the calculation according to the throttle model M2, and mc is according to the intake valve model M3. In-cylinder inflow air flow rate calculated by the above calculation, Ta is the intake air temperature, and κ is the specific heat ratio of air.

Next, the intake valve model M5 will be described. The intake valve model M5 is a model that calculates the in-cylinder inflow air amount based on the model formula 7 and the model formula 8 that are derived using empirical rules.
mc = (Ta / Tm) · (c · Pm−d) (7)
KLfwd = mc · Tint (8)

  In the above model formula 7 and model formula 8, mc is the in-cylinder inflow air flow rate to be calculated by the calculation according to the current intake valve model M5 (hereinafter referred to as “model calculation”), and Ta is the intake air temperature. , Tm is the intake pipe temperature, Pm is the intake pipe pressure, c is a proportional coefficient corresponding to the engine speed and the intake valve opening / closing timing, and d is discharged from the combustion chamber 25 to the exhaust passage in the exhaust stroke. The value corresponding to the amount of burned gas remaining in the combustion chamber 25 and corresponding to the engine speed and the intake valve opening / closing timing, KLfwd is the inflow in the cylinder to be calculated by the current model calculation The amount of air, that is, the total amount of air flowing into the combustion chamber 25 during the intake stroke, and Tint is the time from when the intake valve 32 opens until it closes.

  In the model formula 7, the intake pipe pressure Pm is used as a variable instead of the in-cylinder pressure for the same reason as described in relation to the model formula 4. The proportionality constant c is the same as the proportionality constant c described in relation to the intake valve model M3. Similar to the intake valve model M3, the above-described map Mc (see FIG. 5) is based on the engine speed NE and the intake valve opening / closing timing VT. 7). Further, the value d is the same as the value d described in relation to the intake valve model M3, and the map Md (see FIG. 8) is based on the engine speed NE and the intake valve opening / closing timing VT as in the intake valve model M3. ).

  When the in-cylinder inflow air amount is calculated as described above, a certain time is required until the calculation is completed after the calculation for calculating the in-cylinder inflow air amount is started. There may be a case where a certain time is required from the completion of the calculation for calculating the in-cylinder inflow air amount until the calculated in-cylinder inflow air amount is actually used for controlling the operation of the internal combustion engine. Here, if the amount of change in the cylinder inflow air amount in a short period after the calculation for calculating the cylinder inflow air amount is relatively small, the calculated cylinder inflow air amount is the control of the operation of the internal combustion engine. It can be said that it matches the actual in-cylinder inflow air amount when used in However, when the amount of change in the in-cylinder inflow air amount is relatively large in the short period after the calculation for calculating the in-cylinder inflow air amount, the calculated in-cylinder inflow air amount is used for controlling the operation of the internal combustion engine. Therefore, the actual in-cylinder inflow air amount greatly changes compared to when the calculation for calculating the in-cylinder inflow air amount is started. In this case, the in-cylinder inflow air amount calculated as described above cannot be said to match the actual in-cylinder inflow air amount when it is used for controlling the operation of the internal combustion engine.

  Therefore, in the present embodiment, if the in-cylinder inflow air amount calculated as described above cannot be said to match the actual in-cylinder inflow air amount when used for controlling the operation of the internal combustion engine, the cylinder When it is determined at the time of execution of the calculation for calculating the inflow air amount, the inflow air amount in the cylinder calculated by the calculation is used for controlling the operation of the internal combustion engine. The in-cylinder inflow air amount calculated by the calculation is corrected so as to match.

  That is, the difference between the target throttle opening and the actual throttle opening at the start of the calculation for calculating the in-cylinder inflow air amount (hereinafter referred to as “in-cylinder inflow air amount calculation”) is larger than a predetermined opening degree difference. Sometimes it can be said that the throttle opening has changed relatively greatly in order to make the actual throttle opening the target throttle opening. Therefore, in this embodiment, when the in-cylinder inflow air amount calculation is started, a difference between the target throttle opening and the actual throttle opening (predicted throttle opening in this embodiment) is calculated, and the difference is determined in advance. When the opening degree difference is larger than the difference, the in-cylinder inflow air amount calculated by the in-cylinder inflow air amount calculation (hereinafter also referred to as “model calculation”) according to the models M2 to M5 is corrected as follows.

  That is, when the difference between the predicted throttle opening and the target throttle opening is relatively large at the start of model calculation, it is assumed that the amount of change in the throttle opening in a short period after the start of model calculation is large. When the change amount of the throttle opening is large, it can be said that the change amount of the in-cylinder inflow air amount is also large. For this reason, in the present embodiment, when the difference between the predicted throttle opening and the target throttle opening is larger than a predetermined opening difference, the change amount of the in-cylinder inflow air amount is larger than the predetermined change amount. Judging and correcting the in-cylinder inflow air amount calculated by the model calculation.

  That is, the difference Δmt (k) (=) between the throttle valve passage air flow rate mt (k) before correction calculated by the current model calculation and the throttle valve passage air flow rate mt (k−1) calculated by the previous model calculation. mt (k) −mt (k−1)) is calculated. The difference Δmt (k) calculated here corresponds to the amount of change in the air flow rate through the throttle valve that will change from the start time of the current model calculation to the start time of the next model calculation. Therefore, if this difference Δmt (k) is added to the throttle valve passing air flow rate mt (k) calculated by the current model calculation, the throttle valve passing air flow rate obtained in this way is the actual value at the start of the next model calculation. It can be said that this corresponds to the air flow rate through the throttle valve.

  Therefore, in the present embodiment, correction is performed by adding the difference Δmt (k) calculated as described above to the throttle valve passage air flow rate mt calculated by the current model calculation.

  According to this, if the uncorrected throttle valve passing air flow rate calculated by the current model calculation is larger than the throttle valve passing air flow rate calculated by the previous model calculation, the difference Δmt takes a positive value and is corrected. The subsequent throttle valve passage air flow rate becomes larger by the difference Δmt than the uncorrected throttle valve passage air flow rate. The thus corrected throttle valve passage air flow rate is used for the calculation in accordance with the intake pipe model M4. As a result, the in-cylinder inflow air amount calculated by the current model calculation is the throttle valve before correction. It becomes larger than the in-cylinder inflow air amount calculated when the valve passing air flow rate is used.

  On the other hand, if the uncorrected throttle valve passage air flow calculated by the current model calculation is smaller than the throttle valve passage air flow calculated by the previous model calculation, the difference Δmt takes a negative value. The throttle valve passing air flow rate is smaller than the uncorrected throttle valve passing air flow rate by the difference Δmt. The thus corrected throttle valve passing air flow rate is used for the calculation according to the intake pipe model M4, and as a result, the in-cylinder inflow air calculated by executing the calculation according to the intake valve model M5. The amount is smaller than the in-cylinder inflow air amount calculated when the uncorrected throttle valve passage air flow rate is used.

  If the flow rate of air passing through the throttle valve is corrected in this way, the in-cylinder inflow air amount finally obtained by the model calculation coincides with the actual in-cylinder inflow air amount when it is used for controlling the operation of the internal combustion engine. Or at least not corrected, it becomes closer to the actual in-cylinder inflow air amount than the in-cylinder inflow air amount calculated.

  In the above-described example, whether or not the amount of change in the in-cylinder inflow air amount is larger than a predetermined amount of change is determined based on the difference between the predicted throttle opening and the target throttle opening. Alternatively, or in addition, it may be performed based on the amount of change in the intake pipe pressure. That is, when the change amount of the intake pipe pressure is relatively large, it is presumed that the change amount of the air flow rate through the throttle valve in a short period after the start of the model calculation is large. When the change amount of the throttle valve passing air flow rate is large, it can be said that the change amount of the in-cylinder inflow air amount is also large. Therefore, when the difference ΔPm (k) between the intake pipe pressure Pm (k-1) at the previous model calculation time and the intake pipe pressure Pm (k) at the current model calculation time is larger than the predetermined pressure difference, the cylinder It may be determined that the amount of change in the inflow air amount is larger than a predetermined amount of change.

  In the above-described example, the difference between the uncorrected throttle valve passing air flow rate calculated by the current model calculation and the throttle valve passing air flow rate calculated by the previous model calculation is used as the correction amount for the throttle valve passing air flow rate. However, instead of this, a value calculated as follows may be used as a correction amount for the air flow rate through the throttle valve. That is, the difference ΔPm (k) (= Pm (k) −Pm (k−1)) between the intake pipe pressure Pm (k) at the time of the current model calculation and the intake pipe pressure Pm (k−1) at the time of the previous model calculation. ), And the difference ΔPm (k) is used instead of the intake pipe pressure Pm in the model equation 2 to perform the calculation according to the model equation 2. The value calculated by this calculation is the change amount Δmt (k) of the throttle valve passing air flow rate, and correction is performed by adding this to the throttle valve passing air flow rate mt (k) calculated by the current model calculation.

  According to this, if the intake pipe pressure Pm (k) at the time of the current model calculation is larger than the intake pipe pressure Pm (k-1) at the time of the previous model calculation, the change amount Δmt (k) is a positive value. Therefore, the corrected throttle valve passing air flow rate becomes larger by the change amount Δmt (k) than the uncorrected throttle valve passing air flow rate. The thus corrected throttle valve passage air flow rate is used for the calculation in accordance with the intake pipe model M4. As a result, the in-cylinder inflow air amount calculated by the current model calculation is the throttle valve before correction. It becomes larger than the in-cylinder inflow air amount calculated when the valve passing air flow rate is used.

  On the other hand, if the intake pipe pressure Pm (k) at the time of the current model calculation is smaller than the intake pipe pressure Pm (k-1) at the time of the previous model calculation, the change amount Δmt (k) takes a negative value. Therefore, the corrected throttle valve passing air flow rate is smaller by the change amount Δmt (k) than the uncorrected throttle valve passing air flow rate. The thus corrected throttle valve passage air flow rate is used for the calculation in accordance with the intake pipe model M4. As a result, the in-cylinder inflow air amount calculated by the current model calculation is the throttle valve before correction. It becomes smaller than the in-cylinder inflow air amount calculated when the valve passing air flow rate is used.

  Thus, even if the flow rate of air passing through the throttle valve is corrected, the in-cylinder inflow air amount finally obtained by the model calculation is the actual in-cylinder at the time when the in-cylinder inflow air amount is used for controlling the operation of the internal combustion engine. It is closer to the actual in-cylinder inflow air amount than the in-cylinder inflow air amount calculated when it matches the inflow air amount or at least is not corrected.

  Further, it may be determined whether the amount of change in the in-cylinder inflow air amount is larger than a predetermined amount of change as follows. That is, the ratio of the intake pipe pressure Pm to the intake pressure Pa, that is, the relationship between the pressure ratio Pm / Pa and the throttle valve passing air flow rate mt is as shown in FIG. That is, when the throttle opening θ is constant and the pressure ratio Pm / Pa is smaller than the specific pressure ratio Rs, the throttle valve passing air flow rate is constant regardless of the pressure ratio. On the other hand, when the throttle opening is constant and the pressure ratio is larger than the specific pressure ratio Rs, the larger the pressure ratio, the smaller the throttle valve passing air flow rate. When the pressure ratio is constant, the throttle valve passing air flow rate is larger as the throttle opening is larger.

  This can be expressed as follows, assuming that the intake pressure Pa is substantially equal to the atmospheric pressure, and therefore the intake pressure is substantially constant. That is, when the throttle opening θ is constant and the intake pipe pressure Pm is lower than a specific pressure corresponding to the specific pressure ratio Rs, the throttle valve passing air flow rate mt is constant regardless of the intake pipe pressure. If the opening is constant and the intake pipe pressure is higher than the above specified pressure, the higher the intake pipe pressure, the smaller the throttle valve passing air flow rate. If the intake pipe pressure is constant, the larger the throttle opening, the more throttle It can be said that the flow rate of air passing through the valve is large.

  In any case, when the pressure ratio Pm / Pa increases beyond the specific pressure ratio Rs, the throttle valve passage air flow rate mt greatly changes even if the throttle opening θ is constant. Also, when the pressure ratio increases in a region larger than the specific pressure ratio, the throttle valve passing air flow rate greatly changes even if the throttle opening is constant. Conversely, even when the pressure ratio becomes smaller than the specific pressure ratio, even if the throttle opening is constant, the flow rate of air passing through the throttle valve changes greatly, and the pressure ratio is larger than the specific pressure ratio. Even when the throttle opening is constant, the throttle valve passing air flow rate greatly changes.

  Therefore, when the pressure ratio Pm / Pa increases beyond the specific pressure ratio Rs between the previous model calculation time and the current model calculation time, or increases in a region larger than the specific pressure ratio. Alternatively, when the pressure becomes smaller than the specific pressure ratio, or when the pressure becomes smaller in a region larger than the specific pressure ratio, even if the throttle opening θ is constant, within a short period after the start of the current model calculation. It is determined that the throttle valve passage air flow rate mt changes greatly, and therefore the in-cylinder inflow air amount changes greatly. If it is determined in this way, the difference ΔPm / Pa (k) between the pressure ratio Pm / Pa (k-1) at the previous model calculation time and the pressure ratio Pm / Pa (k) at the current model calculation time. (= Pm / Pa (k−1) −Pm / Pa (k)) is calculated, and the difference ΔPm / Pa (k) thus calculated is used instead of the pressure ratio Pm / Pa in the above model equation 2. Then, the calculation according to the model equation 2 is performed. The value calculated by this calculation is the change amount Δmt (k) of the air flow rate through the throttle valve, and the throttle valve passage that will change between the start of the current model calculation and the start of the next model calculation. It can be considered to correspond to the amount of change in the air flow rate. Therefore, correction is performed by adding the change amount Δmt (k) of the throttle valve passing air flow rate thus calculated to the throttle valve passing air flow rate mt (k) calculated by the current model calculation.

  According to this, if the pressure ratio at the time of the current model calculation is larger than the pressure ratio Pm / Pa at the time of the previous model calculation, the difference ΔPm / Pa takes a negative value, and thus the change amount Δmt is also negative. Since the value is taken, the corrected throttle valve passing air flow rate is smaller than the uncorrected throttle valve passing air flow rate by the change amount Δmt. The thus corrected throttle valve passage air flow rate is used for the calculation in accordance with the intake pipe model M4. As a result, the in-cylinder inflow air amount calculated by the current model calculation is the throttle valve before correction. It becomes smaller than the in-cylinder inflow air amount calculated when the valve passing air flow rate is used.

  On the other hand, if the pressure ratio at the time of the current model calculation is smaller than the pressure ratio Pm / Pa at the time of the previous model calculation, the difference ΔPm / Pa takes a positive value, and therefore the change amount Δmt also has a positive value. Therefore, the corrected throttle valve passing air flow rate becomes larger by the change amount Δmt than the uncorrected throttle valve passing air flow rate. The thus corrected throttle valve passage air flow rate is used for the calculation in accordance with the intake pipe model M4. As a result, the in-cylinder inflow air amount calculated by the current model calculation is the throttle valve before correction. It becomes larger than the in-cylinder inflow air amount calculated when the valve passing air flow rate is used.

  If the flow rate of air passing through the throttle valve is corrected in this manner, the in-cylinder inflow air amount finally obtained by the model calculation is the actual in-cylinder inflow at the time when the in-cylinder inflow air amount is used for controlling the operation of the internal combustion engine. It is closer to the actual in-cylinder inflow air amount than the in-cylinder inflow air amount calculated when it matches the air amount or at least is not corrected.

  In many cases, the throttle valve passing air flow rate increases as the throttle opening increases, and conversely, the throttle valve passing air flow rate decreases as the throttle opening decreases. However, as described with reference to FIG. 9, when the pressure ratio Pm / Pa is larger than the specific pressure ratio Rs, the throttle valve passing air flow rate mt is increased even if the throttle opening θ is constant. Becomes smaller. Therefore, even if the throttle opening becomes large, if the pressure ratio becomes larger than a certain value at this time, the air flow rate through the throttle valve may decrease. If the pressure ratio becomes smaller than a certain value, the flow rate of air passing through the throttle valve may increase.

  Therefore, in addition to the above-described method or in place of the above-described method as a determination as to whether or not the change amount of the in-cylinder inflow air amount within a short period after the start of the model calculation is larger than a predetermined change amount, A technique may be adopted.

  For example, it is assumed that the throttle opening degree θ at the time of the previous model calculation is the opening degree θ1. In this case, the throttle valve passing air flow rate mt changes along the solid line L1 in FIG. 10 according to the pressure ratio Pm / Pa. Therefore, when the pressure ratio at the previous model calculation time is the value R1, the throttle valve passing air flow rate at the previous model calculation time is the value mt1. Here, it is assumed that the throttle opening at the time of the current model calculation is larger than the opening θ1 at the previous model calculation and becomes the opening θ2. In this case, the throttle valve passing air flow rate mt changes along the solid line L2 in FIG. 10 according to the pressure ratio. Here, if the throttle valve passage air flow rate at the time of the current model calculation is equal to the throttle valve passage air flow rate mt1 at the time of the previous model calculation, the pressure ratio at the current model calculation time is a value R2 greater than the specific pressure ratio Rs. Will be. In other words, even if the throttle opening is larger than the opening θ1 and is changed to the opening θ2, the pressure ratio is larger than the value R1 and is changed to a value R2 larger than the specific pressure ratio Rs. If so, the throttle valve passing air flow rate at the time of the current model calculation does not change from the throttle valve passing air flow rate at the time of the previous model calculation. Accordingly, even if the throttle opening is larger than the opening θ1 and is changed to the opening θ2, the throttle valve at the time of the current model calculation is changed if the pressure ratio at the time of the current model calculation is changed to a value larger than the value R2. The passing air flow rate is smaller than the throttle valve passing air flow rate at the time of the previous model calculation. On the other hand, if the pressure ratio changes to a value smaller than the value R2 when the throttle opening is larger than the opening θ1 and changes to the opening θ2, the throttle valve passing air flow rate at the time of this model calculation is the previous time. It becomes larger than the throttle valve passage air flow rate at the time of model calculation.

  If the throttle opening θ at the previous model calculation is the opening θ2, and the pressure ratio Pm / Pa is a value R2 larger than the specific pressure ratio Rs, the throttle valve passing air flow at the previous model calculation is shown. Is the value mt1. Here, it is assumed that the throttle opening at the time of the current model calculation is smaller than the opening θ2 at the previous model calculation and becomes the opening θ1. Here, if the throttle valve passage air flow rate at the current model calculation time is equal to the throttle valve passage air flow rate mt1 at the previous model calculation time, the pressure ratio at the current model calculation time is the value R1. In other words, even if the throttle opening becomes smaller than the opening θ2 and changes to the opening θ1, the current time of the model calculation is as long as the pressure ratio becomes smaller than the value R2 and changes to the value R1. This means that the throttle valve passage air flow rate does not change from the throttle valve passage air flow rate at the time of the previous model calculation. Therefore, even if the throttle opening is smaller than the opening θ2 and is changed to the opening θ1, if the pressure ratio is changed to a value smaller than the value R1, the throttle valve passing air flow rate at the time of this model calculation is It becomes larger than the throttle valve passing air flow rate at the time of model calculation. On the other hand, if the pressure ratio changes to a value larger than the value R1 when the throttle opening is smaller than the opening θ2 and changes to the opening θ1, the flow rate of air passing through the throttle valve at the time of this model calculation is the previous time. It becomes smaller than the throttle valve passage air flow rate at the time of the model calculation.

  As described above, when the pressure ratio at the time of the current model calculation is larger than the pressure ratio at the time of the previous model calculation exceeding the specific pressure ratio, or the pressure ratio at the time of the current model calculation is higher than the specific pressure ratio. When the pressure ratio is larger than the pressure ratio at the time of the previous model calculation in a large area, the throttle valve passing air regardless of whether the throttle opening at the time of the current model calculation has changed from the throttle opening at the time of the previous model calculation. The flow rate changes greatly. Conversely, when the pressure ratio at the time of the current model calculation is smaller than the pressure ratio at the time of the previous model calculation, exceeding a specific pressure ratio, or the pressure ratio at the time of the current model calculation is greater than the specific pressure ratio. Even when the pressure ratio at the time of the previous model calculation is smaller than the throttle opening at the time of the current model calculation, whether the throttle opening at the time of the current model calculation has changed from the throttle opening at the time of the previous model calculation. The flow rate changes greatly.

  Therefore, when the pressure ratio increases beyond the specific pressure ratio between the previous model calculation time and the current model calculation time, or when the pressure ratio increases in a region larger than the specific pressure ratio, or the specific When the pressure ratio exceeds the specified pressure ratio, or when the pressure ratio becomes smaller than the above specified pressure ratio, the air passing through the throttle valve is within a short period after the start of the current model calculation regardless of whether or not the throttle opening is changed. It is determined that the flow rate changes greatly, and therefore the in-cylinder inflow air amount changes greatly. In this case, the difference ΔPm / Pa (k) (= Pm / Pa () between the pressure ratio Pm / Pa (k-1) at the previous model calculation time and the pressure ratio Pm / Pa (k) at the current model calculation time. k-1) −Pm / Pa (k)), and in accordance with the above model equation 2 using the calculated difference ΔPm / Pa (k) instead of the pressure ratio Pm / Pa in the above model equation 2. Perform the calculation. The value calculated by this calculation is the change amount Δmt (k) of the air flow rate through the throttle valve, and the throttle valve passage that will change between the start of the current model calculation and the start of the next model calculation. It can be considered to correspond to the amount of change in the air flow rate. Therefore, correction is performed by adding the change amount Δmt (k) of the throttle valve passing air flow rate thus calculated to the throttle valve passing air flow rate mt (k) calculated by the current model calculation.

  According to this, if the pressure ratio at the time of the current model calculation is larger than the pressure ratio Pm / Pa at the time of the previous model calculation, the difference ΔPm / Pa takes a negative value, and thus the change amount Δmt is also negative. Since the value is taken, the corrected throttle valve passing air flow rate is smaller than the uncorrected throttle valve passing air flow rate by the change amount Δmt. The thus corrected throttle valve passage air flow rate is used for the calculation in accordance with the intake pipe model M4. As a result, the in-cylinder inflow air amount calculated by the current model calculation is the throttle valve before correction. It becomes smaller than the in-cylinder inflow air amount calculated when the valve passing air flow rate is used.

  On the other hand, if the pressure ratio at the time of the current model calculation is smaller than the pressure ratio Pm / Pa at the time of the previous model calculation, the difference ΔPm / Pa takes a positive value, and therefore the change amount Δmt also has a positive value. Therefore, the corrected throttle valve passing air flow rate becomes larger by the change amount Δmt than the uncorrected throttle valve passing air flow rate. The thus corrected throttle valve passage air flow rate is used for the calculation in accordance with the intake pipe model M4. As a result, the in-cylinder inflow air amount calculated by the current model calculation is the throttle valve before correction. It becomes larger than the in-cylinder inflow air amount calculated when the valve passing air flow rate is used.

  If the flow rate of air passing through the throttle valve is corrected in this manner, the in-cylinder inflow air amount finally obtained by the model calculation is the actual in-cylinder inflow at the time when the in-cylinder inflow air amount is used for controlling the operation of the internal combustion engine. It is closer to the actual in-cylinder inflow air amount than the in-cylinder inflow air amount calculated when it matches the air amount or at least is not corrected.

  Note that when it is determined that the amount of change in the in-cylinder inflow air amount within a short period after the start of the model calculation is larger than the predetermined change amount, the throttle valve passing air flow rate calculated by the current model calculation is corrected. In this embodiment, when the intake pipe pressure is constant, the correction for the flow rate of air passing through the throttle valve may be performed as follows.

  That is, when the intake pipe pressure Pm is constant, the intake pipe pressure is not a variable in Equation 2 of the throttle model M2. Further, since the intake pressure Pa and the intake air temperature Ta are approximately equal to the atmospheric pressure and the atmospheric temperature, respectively, and can be considered to be substantially constant, the intake air pressure and the intake air temperature are not variables in the expression 2 of the throttle model M2. Therefore, in this case, the only variable in Equation 2 of the throttle model M2 is the product C (θ) · A (θ) that changes according to the throttle opening θ. The relationship shown in FIG. 5 exists between the throttle opening θ and the product C (θ) · A (θ).

  Therefore, a map Mca that defines the relationship between the throttle opening θ and the product C (θ) · A (θ) is obtained and stored in advance in the ROM 72 in the form as shown in FIG. Since the difference between the predicted throttle opening and the target throttle opening is larger than the predetermined opening difference, the amount of change in the cylinder inflow air amount within a short period after the start of the current model calculation is determined in advance. When the intake pipe pressure Pm is constant from the previous model calculation time to the current model calculation time, the difference Δθ (= θt−) between the predicted throttle opening θe and the target throttle opening θt is determined. Based on θe), a difference ΔC (θ) · A (θ) between the products C (θ) · A (θ) is obtained from the map Mca (see FIG. 5). Then, the calculation according to the model equation 2 is performed using the difference ΔC (θ) · A (θ) thus obtained instead of the product C (θ) · A (θ) in the model equation 2. The value calculated by this calculation is the change amount Δmt (k) of the air flow rate through the throttle valve, and the throttle valve passage that will change between the start of the current model calculation and the start of the next model calculation. It can be considered to correspond to the amount of change in the air flow rate. Therefore, correction is performed by adding the change amount Δmt (k) of the throttle valve passing air flow rate thus calculated to the throttle valve passing air flow rate mt (k) calculated by the current model calculation.

  According to this, if the predicted throttle opening is smaller than the target throttle opening, the difference Δθ takes a positive value, so that the corrected throttle valve passing air flow rate changes more than the uncorrected throttle valve passing air flow rate. It increases by the amount Δmt (k). The thus corrected throttle valve passage air flow rate is used for the calculation in accordance with the intake pipe model M4. As a result, the in-cylinder inflow air amount calculated by the current model calculation is the throttle valve before correction. It becomes larger than the in-cylinder inflow air flow rate calculated when the valve passing air flow rate is used. In this case, it can be said that the calculated in-cylinder inflow air amount matches at least the actual in-cylinder inflow air amount when a short period has elapsed from the start of the current model calculation.

  On the other hand, if the predicted throttle opening is larger than the target throttle opening, the difference Δθ takes a negative value. Therefore, the corrected throttle valve passage air flow rate is more than the change amount Δmt than the uncorrected throttle valve passage air flow rate. It becomes smaller by (k). The thus corrected throttle valve passage air flow rate is used for the calculation according to the intake pipe model M4. As a result, the in-cylinder inflow air amount calculated by the current model calculation is the throttle valve before correction. It becomes smaller than the in-cylinder inflow air flow rate calculated when the valve passing air flow rate is used. Also in this case, it can be said that the calculated in-cylinder inflow air amount coincides with the actual in-cylinder inflow air amount at the time when a short period has elapsed since the start of the current model calculation.

  Of course, as can be seen from FIG. 5, in the curve indicating the relationship between the throttle opening θ and the product C (θ) · A (θ), the product C ( A change amount of θ) · A (θ) is obtained. Therefore, a map defining the relationship between the throttle opening θ and the corresponding inclination is obtained and stored in the ROM 72 in advance, and the inclination is obtained from the map based on the throttle opening θ. A change amount of the product C (θ) · A (θ) may be obtained by multiplying the change amount, and a correction amount for the flow rate of air passing through the throttle valve may be calculated based on the change amount.

  Further, when it is determined that the amount of change in the in-cylinder inflow air amount within a short period after the start of the model calculation is larger than the predetermined change amount, the throttle valve passing air flow rate calculated by the current model calculation is corrected. In the embodiment, when the throttle opening is constant, the correction for the air flow rate through the throttle valve may be performed as follows.

  That is, when the throttle opening θ is constant, the throttle opening is not a variable in Equation 2 of the throttle model M2. Further, since the intake pressure Pa and the intake air temperature Ta are approximately equal to the atmospheric pressure and the atmospheric temperature, respectively, and can be considered to be substantially constant, the intake air pressure and the intake air temperature are not variables in the expression 2 of the throttle model M2. Therefore, in this case, the variable in the equation 2 of the throttle model M2 is only the portion of the value Φ (Pm / Pa) that changes according to the intake pipe pressure Pm. The relationship shown in FIG. 11 exists between the intake pipe pressure Pm and the value Φ (Pm / Pa). That is, when the throttle opening θ is constant and the pressure ratio Pm / Pa is smaller than the specific pressure ratio Rs, the value Φ (Pm / Pa) is constant regardless of the compression ratio. On the other hand, when the throttle opening is constant and the pressure ratio is larger than the specific pressure ratio Rs, the larger the pressure ratio, the smaller the value Φ (Pm / Pa). When the pressure ratio is constant, the value Φ (Pm / Pa) increases as the throttle opening increases.

  Therefore, a map MΦ that defines the relationship among the intake pipe pressure Pm, the throttle opening θ, and the value Φ (Pm / Pa) is obtained and stored in advance in the ROM 72 in the form shown in FIG. The difference ΔPm (k) (= Pm (k−1) −Pm (k) between the intake pipe pressure Pm (k−1) at the previous model calculation time and the intake pipe pressure Pm (k) at the current model calculation time. ) Is larger than a predetermined pressure difference, it is determined that the amount of change in the in-cylinder air flow amount in a short period after the start of the current model calculation is larger than the predetermined amount of change. When the throttle opening θ is constant from the calculation time point to the current model calculation time point, the difference ΔΦ (Pm / Pa) of the value Φ (Pm / Pa) is obtained from the map MΦ based on the difference ΔPm (k). Then, the calculation according to the model equation 2 is performed using the difference ΔΦ (Pm / Pa) thus obtained instead of the value Φ (Pm / Pa) in the model equation 2. The value calculated by this calculation is the change amount Δmt (k) of the air flow rate through the throttle valve, and the throttle valve passage that will change between the start of the current model calculation and the start of the next model calculation. It can be considered to correspond to the amount of change in the air flow rate. Therefore, correction is performed by adding the change amount Δmt (k) of the throttle valve passing air flow rate thus calculated to the throttle valve passing air flow rate mt (k) calculated by the current model calculation.

  According to this, if the intake pipe pressure at the time of the current model calculation is smaller than the intake pipe pressure at the time of the previous model calculation, the difference ΔPm (k) takes a positive value. Is larger than the uncorrected throttle valve passage air flow rate by the change amount Δmt (k). The thus corrected throttle valve passage air flow rate is used for the calculation in accordance with the intake pipe model M4. As a result, the in-cylinder inflow air amount calculated by the current model calculation is the throttle valve before correction. It becomes larger than the in-cylinder inflow air amount calculated when the valve passing air flow rate is used.

  On the other hand, if the intake pipe pressure at the time of the current model calculation is larger than the intake pipe pressure at the time of the previous model calculation, the difference ΔPm (k) takes a negative value, so the corrected flow through the throttle valve is corrected. The change amount Δmt (k) is smaller than the previous throttle valve passage air flow rate. The thus corrected throttle valve passage air flow rate is used for the calculation in accordance with the intake pipe model M4. As a result, the in-cylinder inflow air amount calculated by the current model calculation is the throttle valve before correction. It becomes smaller than the in-cylinder inflow air amount calculated when the valve passing air flow rate is used.

  If the flow rate of air passing through the throttle valve is corrected in this manner, the in-cylinder inflow air amount finally obtained by the model calculation is the actual in-cylinder inflow at the time when the in-cylinder inflow air amount is used for controlling the operation of the internal combustion engine. It is closer to the actual in-cylinder inflow air amount than the in-cylinder inflow air amount calculated when it matches the air amount or at least is not corrected.

  Of course, as can be seen from FIG. 9, in the curve showing the relationship between the pressure ratio Pm / Pa corresponding to each throttle opening θ and the value Φ (Pm / Pa), on the curve corresponding to a specific pressure ratio Pm / Pa. The amount of change in the value Φ (Pm / Pa) can be obtained by multiplying the inclination at the point by the amount of change in the pressure ratio Pm / Pa. Therefore, a map defining the relationship between the throttle opening θ and the pressure ratio Pm / Pa and the corresponding inclination is obtained and stored in the ROM 72 in advance, and the map is determined based on the throttle opening θ and the pressure ratio Pm / Pa. An inclination may be obtained from the map, and a change amount of the value Φ (Pm / Pa) may be obtained by multiplying this by the pressure ratio Pm / Pa, and a correction amount for the throttle valve passing air flow rate may be calculated based on this. .

  Even when the difference ΔPm (k) is larger than a predetermined pressure difference, as can be seen from the relationship between the intake pipe pressure Pm and the value Φ (Pm / Pa) shown in FIG. When the intake pipe pressure at the time of the previous model calculation and the intake pipe pressure at the time of the current model calculation are smaller than the specific pressure Ps, the difference ΔΦ (Pm / Pa) obtained from the map stored in the ROM 72 is zero. Become. For this reason, the change amount Δmt (k) of the throttle valve passage air flow rate calculated by the calculation according to the above model equation 2 becomes zero. Therefore, in this case, as a result, the throttle valve passage air flow rate is not corrected, and the in-cylinder inflow air amount is not corrected.

  Next, an example of a routine for calculating the in-cylinder inflow air amount according to the above-described models M1 to M5 will be described. This routine is shown in FIGS.

  The routine shown in FIG. 13 is a routine for executing a calculation according to the electronically controlled throttle valve model M1, and is executed at every predetermined time interval ΔT1. When this routine is started, first, based on the accelerator pedal depression amount Accp detected by the accelerator opening sensor 65 in step 101, the target throttle opening θt (i + 1) is calculated from the map Mθ shown in FIG. This is obtained and stored in the ROM 72 as the target throttle opening θt (i) after the predetermined delay time TD from the current model calculation time. Next, at step 102, the predicted throttle opening degree θe (i + 1) is calculated according to the above equation 1, and this is stored in the ROM 72 as the predicted throttle opening degree θe (i) after a predetermined delay time TD from the current model calculation time point. Next, at step 103, a drive signal is output to the throttle valve drive actuator 46a so that the throttle opening becomes the target throttle opening stored in the ROM 72 before the predetermined delay time TD as the target throttle opening at the time of the current model calculation. The routine ends.

  The routine shown in FIGS. 14 to 16 is a routine for executing calculations according to the throttle model M2, the intake valve model M3, the intake pipe model M4, and the intake valve model M5, and is executed at each predetermined time interval ΔT2. Is done. When this routine is started, first, in step 201, the target throttle opening degree θt stored in the ROM 72 by the execution of the routine of FIG. 13 is a time point later than the current model calculation time point. The target throttle opening θt at the time closest to the time is read as the target throttle opening θt (k−1) used for the current model calculation. Next, in step 202, the predicted throttle opening θe stored in the ROM 72 by the execution of the routine of FIG. 13 is predicted at a time point later than the current model calculation time point and closest to the calculation time point. The throttle opening degree θe is read as the predicted throttle opening degree θe (k−1) used for the current model calculation.

  Next, in step 203, the absolute difference Δθ (k-1) between the target throttle opening θt (k-1) read in step 201 and the predicted throttle opening θe (k-1) read in step 202 is absolute. It is determined whether or not the value is larger than a predetermined opening degree difference Δθs (| Δθ (k−1) |> Δθs). Here, when it is determined that | Δθ (k−1) |> Δθs, that is, when it is determined that the in-cylinder inflow air amount greatly changes between the current model calculation time and the next model calculation time, the routine is performed. Advances to step 204 to step 208 where the calculation according to the throttle model M2 and the correction of the throttle valve passing air flow rate calculated by the calculation are performed. That is, based on the predicted throttle opening θe (k−1) read in step 202 in step 204, the value C (θ) (k−1) · A (θ) (k) from the map Mca (see FIG. 5). -1) is required. Next, at step 205, the pressure ratio Pm (k-1) / Pa (k-1) of the intake pipe pressure Pm (k-1) at the previous model calculation time to the intake pressure Pa (k-1) at the previous model calculation time. Based on the above, the value Φ (Pm (k−1) / Pa (k−1)) is obtained from the map MΦ (see FIG. 6). Next, at step 206, the value C (θ) (k-1) · A (θ) (k-1) obtained at step 204 and the value Φ (Pm (k-1) / Pa (k-1)), the intake pipe pressure Pm (k-1) at the previous model calculation time, and the intake pipe temperature Tm (k-1) at the previous model calculation time, A throttle valve passage air flow rate mt (k-1) is calculated.

  Next, at step 207, the difference Δmt (k-1) between the throttle valve passage air flow rate mt (k-1) calculated at step 206 and the throttle valve passage air flow rate mt (k-2) calculated by the previous model calculation. ) (= Mt (k-1) -mt (k-2)) is calculated. Next, in step 208, a correction is performed in which the difference Δmt (k−1) calculated in step 207 is added to the throttle valve passing air flow rate mt (k−1) calculated in step 206, and the routine is performed by the intake valve. It progresses to step 209-step 211 which performs the calculation according to the model M3. Therefore, according to this, when it is determined in step 203 that the in-cylinder inflow air amount greatly changes between the current model calculation time and the next model calculation time, the corrected throttle valve passage is performed in the model calculation after step 209. The air flow rate is used, and as a result, the inflow amount in the cylinder calculated by the current model calculation is corrected.

  On the other hand, when it is determined in step 203 that | Δθ (k−1) | ≦ Δθs, that is, between the current model calculation time and the next model calculation time, the in-cylinder inflow air amount does not change significantly. When it is determined, the routine proceeds to step 218 to step 220 in FIG. 15 which executes the calculation according to the throttle model M2. That is, based on the predicted throttle opening θe (k−1) read in step 202 in step 218, the value C (θ) (k−1) · A (θ) (k) from the map Mca (see FIG. 5). -1) is required. Next, at step 219, the pressure ratio Pm (k-1) / Pa (k-1) of the intake pipe pressure Pm (k-1) at the previous model calculation time to the intake pressure Pa (k-1) at the previous model calculation time. Based on the above, the value Φ (Pm (k−1) / Pa (k−1)) is obtained from the map MΦ (see FIG. 6). Next, at step 220, the value C (θ) (k-1) · A (θ) (k-1) obtained at step 218 and the value Φ (Pm (k-1) / Pa (k-1)), the intake pipe pressure Pm (k-1) at the previous model calculation time, and the intake air temperature Tm (k-1) at the previous model calculation time, the throttle according to the above model equation 2 The valve passing air flow rate mt (k-1) is calculated, and the routine proceeds to Steps 209 to 211 for executing a calculation according to the intake valve model M3. Therefore, according to this, when it is determined in step 203 that the in-cylinder inflow air amount does not change significantly between the current model calculation time and the next model calculation time, the throttle valve passing air flow rate calculated in step 220 is calculated. The correction to mt (k-1) is not performed, and the uncorrected throttle valve passage air flow rate is used in the model calculation after step 209. As a result, the in-cylinder calculated by the current model calculation is used. The inflow air amount is not corrected.

  In step 209, the value c (k-1) is obtained from the map Mc (see FIG. 7) based on the engine speed NE (k-1) and the intake valve opening / closing timing VT (k-1) at the time of the current model calculation. It is done. Next, at 210, the value d (k-1) is obtained from the map Md (see FIG. 8) based on the engine speed NE (k-1) and the intake valve opening / closing timing VT (k-1) at the time of the current model calculation. It is done. Next, at step 211, the value c (k-1) obtained at step 209, the value d (k-1) obtained at step 210, and the intake air temperature Ta (k-1) at the previous model calculation time. In-cylinder inflow air flow rate mc () according to the above model equation 4 based on the intake pipe temperature Tm (k-1) at the previous model calculation time and the intake pipe pressure Pm (k-1) at the previous model calculation time. k-1) is calculated.

  Next, the routine proceeds to step 212 in FIG. That is, in step 212, the throttle valve passage air flow rate mt (k-1) calculated in step 208 or step 220, the cylinder inflow air flow rate mc (k-1) calculated in step 211, and the previous time. The intake pipe pressure Pm (k) and the intake pipe temperature Tm (k) are calculated according to the model formula 5 and the model formula 6 based on the intake temperature Ta (k-1) at the time of model calculation.

  Next, the routine proceeds to step 213 to step 217 for executing calculation according to the intake valve model M5. That is, in step 213, the value c (k-1) is obtained from the map Mc (see FIG. 7) based on the engine speed NE (k-1) and the intake valve opening / closing timing VT (k-1) at the time of the current model calculation. Desired. Next, at step 214, a value d (k-1) is obtained from the map Md (see FIG. 8) based on the engine speed NE (k-1) and the intake opening / closing timing VT (k-1) at the time of the current model calculation. It is done. Next, at 215, the value c (k-1) calculated at step 213, the value d (k-1) calculated at step 214, the intake pipe pressure Pm (k) calculated at step 212, and the like. Similarly, the in-cylinder inflow air flow rate mc (k) according to the model equation 4 based on the intake pipe temperature Tm (k) calculated in step 212 and the intake air temperature Ta (k-1) at the time of the previous model calculation. Is calculated. Next, at step 216, the intake valve opening time Tint (k) is calculated based on the engine speed NE (k-1) and the intake valve opening / closing timing VT (k-1) at the time of the current model calculation. Next, in step 217, in-cylinder inflow air according to the above equation 8 based on the in-cylinder inflow air flow rate mc (k) calculated in step 215 and the intake valve opening time Tint (k) calculated in step 216. The quantity KLfwd (k) is calculated and the routine ends.

  Note that a determination based on the change amount of the intake pipe pressure is adopted as a determination as to whether or not the in-cylinder inflow air amount greatly changes between the current model calculation time and the next model calculation time in step 203 in FIG. May be. In this case, in step 203 in FIG. 14, the absolute value of the difference ΔPm (k) between the intake pipe pressure Pm (k−1) at the previous model calculation time and the intake pipe pressure Pm (k) at the current model calculation time is calculated. It may be determined whether or not the pressure difference is larger than a predetermined pressure difference ΔPms (| ΔPm (k) |> ΔPms). In this case, when it is determined that | ΔPm (k) |> ΔPms, the routine proceeds to step 204 in FIG. 14, whereas when it is determined that | ΔPm (k) | ≦ ΔPms, the routine proceeds to step 218 in FIG. Like that.

  Similarly, the other determination described above as a determination of whether or not the change amount of the in-cylinder inflow air amount is larger than a predetermined change amount may be adopted in the determination in step 203 of FIG.

  Further, as a correction amount for the throttle valve passage air flow rate in step 207 of FIG. 14, a difference ΔPm () between the intake pipe pressure Pm (k) at the current model calculation time and the intake pipe pressure Pm (k-1) at the previous model calculation time. A correction amount calculated based on k) may be adopted. In this case, in step 207, the difference ΔPm (k) (= Pm (k) −Pm) between the intake pipe pressure Pm (k) at the time of the current model calculation and the intake pipe pressure Pm (k−1) at the time of the previous model calculation. (k-1)) is used instead of the intake pipe pressure Pm, and the calculation according to the above model equation 2 is performed, and the value calculated by this calculation, that is, the change amount Δmt (k) of the throttle valve passage air flow rate is calculated. In step 208, a correction amount for the throttle valve passing air flow rate is added to the throttle valve passing air flow rate mt (k-1).

  Similarly, the other correction amount described above may be adopted as the correction amount in step 207 of FIG. 14 as the correction amount for the throttle valve passing air flow rate.

  Incidentally, an internal combustion engine having a supercharger 91 as shown in FIG. 17 is known. Next, a case where the present invention is applied to an internal combustion engine provided with such a supercharger 91 will be described. In the internal combustion engine shown in FIG. 17, the compressor 91 a of the supercharger 91 is disposed in the intake duct 43 upstream of the throttle valve 46. On the other hand, an exhaust turbine 91 b of the supercharger 91 is disposed in the exhaust pipe 51. The compressor 91a is connected to an exhaust turbine 91b. When the exhaust turbine 91b is rotated by exhaust gas, the rotation of the exhaust turbine 91b is transmitted to the compressor 91a, and the compressor 91a is rotated. When the compressor 91a is rotated, the compressor 91a discharges air while compressing it downstream.

  A compressor rotation speed sensor 63 for detecting the rotation speed of the compressor 91a is attached to the intake duct 43 in the vicinity of the compressor 91a. The compressor rotation speed sensor 63 outputs a signal every time the compressor 91a rotates 360 °. The compressor speed sensor 63 is connected to an interface 75 of the electric control device 70, and a signal output from the compressor speed sensor 63 is supplied to the CPU 71 via the interface 75.

  An intercooler 45 that cools the air flowing through the intake duct 43 is disposed in the intake duct 43 between the compressor 91a and the throttle valve 46. The intercooler 45 cools the air flowing in the intake duct 43 by the air outside the internal combustion engine 10.

  The configuration other than the above-described configuration of the internal combustion engine shown in FIG. 17 is the same as the configuration of the internal combustion engine shown in FIG.

  Next, an outline of a method for calculating the amount of air taken into the combustion chamber during the intake stroke in the internal combustion engine shown in FIG. 17, that is, the in-cylinder inflow air amount will be described.

  As shown in the functional block diagram of FIG. 18, the in-cylinder inflow air amount calculation device of the present embodiment includes an electronically controlled throttle valve model M1, a throttle model M2, an intake valve model M3, an intake pipe model M4, The in-cylinder inflow air amount is calculated using the intake valve model M5, the compressor model M6, and the intercooler model M7.

  The function of each model will be briefly described. The electronically controlled throttle valve model M1 is the same model as the electronically controlled throttle valve model M1 of the embodiment described with reference to FIGS. 1 to 16 (hereinafter referred to as “first embodiment”). is there. The throttle model M2 is a model for calculating the throttle valve passing air flow rate, and is the same model as the throttle model M2 of the first embodiment. The intake valve model M3 is a model for calculating the intake valve passing air flow rate. The intake pipe model M3 is a model similar to the intake valve model M3 of the first embodiment, and the intake pipe model M4 is a model for calculating the intake pipe pressure and the intake pipe temperature, and is the same model as the intake pipe model M4 of the first embodiment. The intake valve model M5 is a model for calculating the in-cylinder inflow air amount and is the same model as the intake valve model M5 of the first embodiment.

  Further, the compressor model M6 is a model for calculating the flow rate of air flowing out from the compressor 91a (hereinafter referred to as “compressor outflow air flow rate”), and the intercooler model M7 is the pressure of air in the intercooler 45 (hereinafter referred to as “intercooler pressure”). And a temperature of air in the intercooler 45 (hereinafter referred to as “intercooler temperature”).

  Next, details of the calculation method of the in-cylinder inflow air amount in the internal combustion engine shown in FIG. 17 will be described together with the details of each model. Since the electronically controlled throttle valve model M1 is the same as the electronically controlled throttle valve model M1 of the first embodiment, description thereof is omitted. The calculation according to the throttle model M2, the intake valve model M3, the intake pipe model M4, the compressor model M6, the intercooler model M7, and the intake valve model M5, which will be described below, is performed as a series of calculations as in the first embodiment. It is executed every interval ΔT2.

First, a throttle model M2 of this embodiment (hereinafter also referred to as “second embodiment”) will be described. The throttle model M2 of the second embodiment is a throttle based on the following model formula 9 and model formula 10 derived using physical laws such as mass conservation law, energy conservation law, momentum conservation law, and gas equation of state. This is a model for calculating the valve passing air flow rate.

  In the above model formula 9 and model formula 10, mt is the throttle valve passing air flow rate to be calculated by the calculation according to the current throttle model M2 (hereinafter referred to as “model calculation”), and θ is the throttle opening degree. , C (θ) is a flow coefficient corresponding to the throttle opening θ, A (θ) is a throttle flow path area corresponding to the throttle opening θ, and Pm is a calculation according to the intake pipe model M4 (details are given below) Intake pipe pressure calculated by the following), R is a gas constant, and κ is a specific heat ratio of air. Pi is the intercooler pressure calculated by the calculation (details will be described later) according to the intercooler model M7, that is, the pressure of the air in the intercooler 45, and Ti is the calculation according to the intercooler model M7 (for details). This is the intercooler temperature calculated by (described later), that is, the temperature of the air in the intercooler 45. In this embodiment, κ is a constant value.

  The product C (θ) · A (θ) of the model equation 9 is obtained from the map Mca shown in FIG. 5 based on the predicted throttle opening θe calculated by the calculation according to the electronic control throttle valve model M1. It is done. Further, the value Φ (Pm / Pi) is predicted to be the ratio (hereinafter referred to as “pressure ratio”) Pm / Pi of the intake pipe pressure Pm to the intercooler pressure Pi calculated by an operation (details will be described later) according to the intercooler model M7. A map MΦ shown in FIG. 19 is obtained based on the throttle opening θe.

Next, the intake valve model M3 of the second embodiment will be described. The intake valve model M3 of the second embodiment is a model that calculates the in-cylinder inflow air flow rate based on the following model equation 11 derived using an empirical rule.
mc = (Ti / Tm) · (c · Pm−d) (11)

  In the model equation 11, mc is the in-cylinder inflow air flow rate to be calculated by the calculation according to the current intake valve model M3 (hereinafter referred to as “model calculation”), and Tm is the calculation according to the intake pipe model M4. (C) is a proportional coefficient corresponding to the engine speed and intake valve opening / closing timing, and d is not discharged from the combustion chamber 25 to the exhaust passage in the exhaust stroke. It is a value corresponding to the amount of burnt gas remaining in the combustion chamber 25 and corresponding to the engine speed and the intake valve opening / closing timing, and Ti is calculated by an intercooler model M7 (details will be described later). This is the calculated intercooler temperature.

  The proportional coefficient c is obtained from the map Mc shown in FIG. 7 based on the engine speed NE and the intake valve opening / closing timing VT. On the other hand, the value d is obtained from the map Md shown in FIG. 8 based on the engine speed NE and the intake valve opening / closing timing VT.

  Next, the compressor model M6 will be described. The compressor model M6 is a model for calculating the compressor outflow air flow rate, that is, the flow rate of air flowing out of the compressor 45.

  By the way, the compressor outflow air flow rate is empirically based on the ratio between the intercooler pressure and the intake pressure (the intake pressure in the second embodiment refers to the pressure of the air in the intake duct 43 upstream of the compressor 45) and the compressor speed. Can be estimated. That is, the relationship between the compressor outlet air flow rate mcm and the intercooler pressure Pi divided by the intake pressure Pa (hereinafter referred to as “pressure ratio”) Pi / Pa and the compressor rotational speed NC as shown in FIG. The compressor outflow air flow rate mcm decreases as the value Pi / Pa increases, and increases as the compressor rotational speed Nc increases. The compressor outflow air flow rate can be obtained in advance by experiments or the like as a value based on the pressure ratio and the compressor rotation speed NC. Therefore, in the second embodiment, a map Mmcm that defines the relationship among the pressure ratio Pi / Pa, the compressor rotation speed NC, and the compressor outflow air flow rate mcm is obtained and stored in the ROM 72 in advance as shown in FIG. Let me. The compressor model M6 calculates the compressor outflow air flow rate mcm from the map Mmcm based on the value Pi / Pa and the compressor rotational speed NC.

  Next, the intercooler model M7 will be described. The intercooler model M7 executes the calculation according to the current intercooler model M7 based on the following model formula 12 and model formula 13 derived using the mass conservation law and the energy conservation law (hereinafter referred to as “model calculation”). This is a model for calculating the intercooler pressure and the intercooler temperature at the time.

d (Pi / Ti) / dt = (R / Vi) · (mcm−mt) (12)
dPi / dt = κ · (R / Vi) · (mcm · Ta-mt · Ti)
+ (Κ-1) / Vi. (Ec-K. (Ti-Ta)) (13)

  In the above model formula 12 and model formula 13, Pi is the intercooler pressure to be calculated by the current model calculation, Ti is the intercooler temperature to be calculated by the current model calculation, and Vi is the discharge of the compressor 91a. This is the volume of the intake passage between the outlet and the throttle valve 46, mcm is the compressor outflow air flow rate at the time of the current model calculation calculated by the calculation according to the compressor model M6, and Ec is compressed by the compressor 91a. Is the energy given to the air (the calculation method will be described later), mt is the air flow rate through the throttle valve at the time of the current model calculation calculated by the calculation according to the throttle model M2, and Ta is the current model calculation. Is the intake air temperature at the time, R is the gas constant, and κ is the air A heat ratio, K is a coefficient (described in detail later).

Here, a method for deriving the model expression 12 and the model expression 13 will be described. The portion of the intake passage between the compressor 91a and the throttle valve 46t is referred to as an intercooler portion, and when the total amount of air in the intercooler portion is defined as the total air amount M, the amount of change dM / unit time of the total air amount M Since dt is the difference between the compressor outflow air flow rate mcm corresponding to the flow rate of air flowing into the intercooler section and the throttle valve passing air flow rate mt corresponding to the flow rate of air flowing out of the intercooler section, dt is based on the law of conservation of mass. The following Expression 14 is established.
dM / dt = mcm-mt (14)

Further, the following equation 15 is established based on the state equation for the air in the intercooler.
Pi · Vi = M · R · Ti (15)

  If the above equation 14 is substituted into the above equation 15 to eliminate the total air amount M, and considering that the volume Vi of the intercooler section is constant, the above model equation 12 is obtained.

On the other hand, the amount of change in the energy of the air in the intercooler section is defined as the amount of energy change Ei in the intercooler, and the energy of the air before being compressed by the compressor 91a is defined as the pre-compression air energy Ea. Is the energy imparted to the compressor Ec, the energy of the air discharged from the wall of the intercooler 45 to the outside is the radiating air energy Ed, and the energy of the air flowing out from the intercooler is the effluent air energy Et. From the energy conservation law, the following equation 16 is established for the air in the intercooler section.
Ei = Ea + Ec−Ed−Et (16)

  The amount of energy change Ei in the intercooler is equal to a value obtained by subtracting the radiant air energy Ed and the outflow air energy Et from the sum of the energy of the air flowing into the intercooler, that is, the pre-compression air energy Ea and the compressor applied energy Ec.

Of these energies, the pre-compression air energy Ea and the outflow air energy Et can be calculated according to the following equations 17 and 18, respectively.
Ea = Cp · mcm · Ta (17)
Et = Cp · mt · Ti (18)

  In the above equations 17 to 19, Cp is the constant pressure specific heat of air, mcm is the compressor outflow air flow rate, Ta is the intake air temperature, mt is the throttle passage air flow rate, and Ti is the intercooler temperature.

The compressor imparted energy Ec can be calculated according to the following equation 19.

  In the above equation 19, Cp is the constant pressure specific heat of air, mcm is the compressor outflow air flow rate, Ta is the intake air temperature, Pi is the intercooler pressure, Pa is the intake pressure, and η is the compressor efficiency. is there.

That is, the flow rate of the air flowing into the compressor 91a is the compressor inflow air flow rate mci, the temperature of the air flowing into the compressor is the compressor inflow air temperature Tci, the flow rate of the air flowing out of the compressor is the compressor outflow air flow rate mco, and the outflow from the compressor When the temperature of the air to be discharged is the compressor outflow air temperature Tco, the energy Eci of the air flowing into the compressor and the energy Eco of the air flowing out of the compressor are expressed by the following equations 20 and 21, respectively.
Eci = Cp · mci · Tci (20)
Eco = Cp · mco · Tco (21)

Here, since the sum of the energy Eci flowing into the compressor and the energy imparted by the compressor Ec is equal to the energy Eco of the air flowing out from the compressor, the following equation 22 is obtained using the above equation 20 and the above equation 21 based on the energy conservation law. To establish.
Cp · mci · Tci + Ec = Cp · mco · Tco (22)

In consideration of the fact that the flow rate of air flowing into the compressor is equal to the flow rate of air flowing out of the compressor, the following equation 23 is obtained by modifying the above equation 22.
Ec = Cp · mco · (Tco−Tci) (23)

On the other hand, the compressor efficiency η is expressed by the following equation 24.

In the above equation 24, Tci is the temperature of the air flowing into the compressor, Pio is the pressure of the air flowing out of the compressor, Pi is the intercooler pressure, Tio is the temperature of the air flowing out of the compressor, κ Is the specific heat ratio of air.

Substituting the above equation 24 into the above equation 22 and modifying it, the following equation 25 is obtained.

  Here, it can be said that the pressure Pci and the temperature Tci of the air flowing into the compressor are equal to the intake pressure Pa and the intake temperature Ta, respectively. It can also be said that the pressure Pco of the air flowing out from the compressor is equal to the intercooler pressure Pi. Further, the flow rate mco of the air flowing out from the compressor is the compressor outflowing air flow rate mcm. Therefore, if the above equation 25 is modified in consideration of these, the above equation 19 is obtained.

  There is a relationship as shown in FIG. 22 among the compressor outflow air flow rate, the compressor rotation speed, and the compressor efficiency. That is, the compressor efficiency η increases as the compressor outflow air flow rate increases until the compressor outflow air flow rate reaches a certain constant flow rate when the compressor rotation speed is constant. When the compressor outflow air flow rate exceeds a certain flow rate, the compressor efficiency η increases. The larger the outflow air flow, the smaller. That is, the compressor efficiency η peaks when the compressor outflow air flow rate reaches a certain constant flow rate. The peak of the compressor efficiency η increases as the compressor outflow air flow rate increases, and the compressor outflow air flow rate at which the compressor efficiency η reaches a peak increases as the compressor rotation speed increases. The compressor efficiency can be obtained in advance by experiments or the like as a value based on the compressor outflow air flow rate and the compressor rotation speed. Therefore, in this embodiment, a map Mη that defines the relationship among the compressor outflow air flow rate mcm, the compressor rotation speed Nc, and the compressor efficiency η is obtained and stored in advance in the ROM 72 in the form shown in FIG. The intercooler model M7 obtains the compressor efficiency η from the map Mη based on the compressor outflow air flow rate mcm and the compressor rotational speed Nc calculated by calculation according to the compressor model M6.

  In the above description, the energy given to the air from the compressor contributes to the temperature rise of the air from the flow into the compressor until it flows out, and the contribution to the motion of the air is ignored.

Further, the discharge air energy Ed can be calculated according to the following equation (26).
Ed = K · (Ti-Ta) (26)

  In the above equation 26, K is a coefficient corresponding to the product of the surface area of the intercooler 45 and the heat transfer coefficient from the air in the intercooler 45 to the wall of the intercooler 45, Ti is the intercooler temperature, and Ta is The intake air temperature.

  That is, the discharge air energy Ed is proportional to the difference between the intercooler temperature Ti and the wall temperature Tw of the intercooler 45 based on empirical rules. Here, since the intercooler 45 cools the air in the intercooler by the air outside the internal combustion engine 10, the temperature Tw of the wall of the intercooler 45 is equal to the temperature outside the internal combustion engine 10, resulting in the intake air temperature. It can be said that it is equal to Ta. Accordingly, the discharged air energy Ei is proportional to the difference between the intercooler temperature Ti and the intake air temperature Ta. From this, the above equation 26 holds.

The intercooler energy change amount Ei is expressed by the following equation (27).
Ei = d (M · Cv · Ti) / dt (27)

  In the above equation 27, M is the total air amount, Cv is the constant volume specific heat of air, and Ti is the intercooler temperature.

Therefore, the following equation 28 is obtained from the above equations 16 to 27.
d (M · Cv · Ti) / dt = Cp · mcm · Ta + Ec
-K. (Ti-Ta) -Cp.mt.Ti (28)

The specific heat ratio κ is expressed by the following expression 29, and the Meyer's relationship is expressed by the following expression 30. Therefore, when the above expression 28 is transformed using these expressions 29 and 30, the above expression 13 is obtained.
κ = Cp / Cv (29)
Cp = Cv + R (30)

Next, the intake pipe model M4 of the second embodiment will be described. The intake pipe model M4 of the second embodiment is a model for calculating the intake pipe pressure and the intake pipe temperature based on the following model formula 31 and model formula 32 derived using the mass conservation law and the energy conservation law.
d (Pm / Tm) / dt = (R / Vm) · (mt−mc) (31)
dPm / dt = κ · (R / Vm) · (mt · Ti-mc · Tm) (32)

  In the above model equation 31 and model equation 32, Pm is the intake pipe pressure to be calculated by the current model calculation, Tm is the intake pipe temperature to be calculated by the current model calculation, and R is the gas constant. , Vm is the volume of the intake passage between the throttle valve 46 and the intake valve 32, mt is the air flow rate through the throttle valve calculated by the calculation according to the throttle model M2, and mc is according to the intake valve model M3. The in-cylinder inflow air flow rate calculated by the above calculation, Ti is the intercooler temperature calculated by the calculation according to the intercooler model M7, and κ is the specific heat ratio of air.

Next, the intake valve model M5 of the second embodiment will be described. The intake valve model M5 of the second embodiment is a model that calculates the in-cylinder inflow air amount based on the following model equation 33 and model equation 34 derived using empirical rules.
mc = (Ti / Tm) · (c · Pm−d) (33)
KLfwd = mc · Tint (34)

  In the above model equation 33 and model equation 34, mc is the in-cylinder inflow air flow rate to be calculated by the calculation according to the current intake valve model M5 (hereinafter referred to as “model calculation”), and Ti is the intercooler temperature. Yes, Tm is the intake pipe temperature, c is a proportional coefficient corresponding to the engine speed and the intake valve opening / closing timing, and d is not exhausted from the combustion chamber 25 to the exhaust passage in the exhaust stroke but into the combustion chamber 25 The value corresponding to the amount of remaining burned gas and corresponding to the engine speed and the intake valve opening / closing timing, KLfwd is the in-cylinder inflow air amount to be calculated by this model calculation, and Tint is This is the time from when the intake valve 32 opens until it closes.

  The proportionality constant c is the same as the proportionality coefficient c described in relation to the intake valve model M3. Similar to the intake valve model M3, the above-described map Mc (see FIG. 7). Further, the value d is the same as the value d described in relation to the intake valve model M3, and the map Md (see FIG. 8) is based on the engine speed NE and the intake valve opening / closing timing VT as in the intake valve model M3. ).

  When the compressor outflow air flow rate is calculated as described above, a certain time is required until the calculation is completed after the calculation for calculating the compressor outflow air flow rate is started. Also, after the calculation for calculating the compressor outflow air flow rate is completed, the cylinder inflow air amount calculated by using the calculated compressor outflow air flow rate is constant until it is actually used for controlling the operation of the internal combustion engine. It may take a long time. Here, when the change amount of the compressor outflow air flow rate in a short period after the start of the calculation for calculating the compressor outflow air flow rate is relatively small, the calculated compressor outflow air flow rate is calculated using the compressor outflow air flow rate. The in-cylinder inflow air amount coincides with the actual compressor outflow air flow rate when it is used for controlling the operation of the internal combustion engine. It can be said that the amount also corresponds to the actual in-cylinder inflow air amount when it is used for controlling the operation of the internal combustion engine. However, if the amount of change in the compressor outflow air flow rate in the short period after the start of the calculation for calculating the inflow air amount in the cylinder is relatively large, the inflow air amount in the cylinder calculated using the calculated compressor outflow air flow rate Is used for controlling the operation of the internal combustion engine, the actual compressor outflow air flow rate changes greatly compared to when the calculation for calculating the compressor outflow air flow rate is started. In this case, the compressor outflow air flow rate calculated as described above is an actual compressor when the cylinder inflow air amount calculated using the compressor outflow air flow rate is used for controlling the operation of the internal combustion engine. Therefore, the in-cylinder inflow air amount calculated by using the compressor outflow air flow rate is also the actual in-cylinder when it is used for controlling the operation of the internal combustion engine. It cannot be said that it corresponds to the inflow air amount.

  Therefore, in the second embodiment, when the compressor outflow air flow rate calculated as described above is used for the control of the operation of the internal combustion engine, the actual amount of the inflow cylinder air calculated using the compressor outflow air flow rate is actually used. If it is determined at the time of execution of the calculation for calculating the in-cylinder inflow air amount that it cannot be said that it matches the compressor outflow air flow rate, the in-cylinder inflow air amount calculated by the calculation The compressor outflow air flow rate calculated by the calculation according to the compressor model M6 is corrected so as to coincide with the actual in-cylinder inflow air amount when it is used for the control.

  That is, when the difference between the target throttle opening and the actual throttle opening at the start of the cylinder inflow air amount calculation (that is, the calculation for calculating the cylinder inflow air amount) is larger than a predetermined opening difference, It can be said that this is when the throttle opening changes relatively greatly in order to set the throttle opening to the target throttle opening. Therefore, in this embodiment, when the in-cylinder inflow air amount calculation is started, a difference between the target throttle opening and the actual throttle opening (predicted throttle opening in this embodiment) is calculated, and the difference is determined in advance. When the opening degree difference is larger, the compressor outflow air flow rate calculated by the calculation according to the compressor model M5 is corrected as follows, and as a result, the inflow into the cylinder is calculated using the compressor outflow air flow rate. Correct the air volume.

  That is, if the difference between the predicted throttle opening and the target throttle opening is relatively large at the start of the cylinder inflow air amount calculation (hereinafter also referred to as “model calculation”) according to the models M2 to M7, It is assumed that the amount of change in the throttle opening during a short period is large. When the change amount of the throttle opening is large, it can be said that the change amount of the air flow rate through the throttle valve is large, and therefore the change amount of the compressor outflow air flow rate is also large. For these reasons, in this embodiment, when the difference between the predicted throttle opening and the target throttle opening is larger than a predetermined opening difference, the amount of change in the compressor outflow air flow rate is larger than the predetermined amount of change, and accordingly It is determined that the change amount of the in-cylinder inflow air amount is also larger than the predetermined change amount, and the compressor outflow air flow rate calculated by the calculation according to the compressor model M6 is corrected.

  That is, there is a relationship as shown in FIG. 24 among the intercooler pressure Pi, the compressor rotational speed NC, and the compressor outflow air flow rate mcm. That is, if the compressor rotational speed NC is constant, the larger the intercooler pressure Pi, the smaller the compressor outflow air flow rate mcm. If the intercooler pressure Pi is constant, the larger the compressor rotational speed NC, the greater the compressor outflow air flow rate. Here, as can be seen from FIG. 24, in the curve showing the relationship between the intercooler pressure corresponding to each compressor speed and the compressor outflow air flow rate, the intercooler is inclined at a point on the curve corresponding to a specific intercooler pressure. By multiplying the amount of change in pressure, the amount of change in the compressor outflow air flow rate is obtained. Therefore, in this embodiment, a map Mdmcm that defines the relationship between the compressor rotational speed NC, the intercooler pressure Pi, and the corresponding inclination dmcm is obtained and stored in advance in the ROM 72 in the form as shown in FIG. . When it is determined that the amount of change in the compressor outflow air flow rate is greater than a predetermined amount of change, the slope dmcm is obtained from the map Mdmcm based on the compressor rotational speed NC and the intercooler pressure Pi. The difference ΔPi (k) (= Pi (k) −Pi (k−1) between the intercooler pressure Pi (k) at the time of the current model calculation and the intercooler pressure Pi (k−1) at the time of the previous model calculation. ) And the calculated difference ΔPi (k) is multiplied by the slope dmcm to calculate the correction amount Δmcm (k) for the compressor outflow air flow rate. The difference Δmcm (k) calculated here corresponds to the amount of change in the compressor outflow air flow rate that will change from the start time of the current model calculation to the start time of the next model calculation. Therefore, if this difference Δmcm (k) is added to the compressor outflow air flow rate mcm (k) calculated by the current model calculation, the compressor outflow air flow rate thus obtained becomes the actual compressor at the start of the next model calculation. It can be said that it matches or is close to the outflow air flow rate.

  Therefore, in this embodiment, correction is performed by adding the correction amount Δmcm calculated as described above to the compressor outflow air flow rate mcm calculated by the current model calculation.

  According to this, if the intercooler pressure calculated by the current model calculation is higher than the intercooler pressure calculated by the previous model calculation, the difference ΔPi takes a positive value and the slope dmcm is a negative value. Therefore, since the correction amount Δmcm has a negative value, the corrected compressor outflow air flow rate is smaller than the uncorrected compressor outflow air flow rate by the correction amount Δmcm. Then, the corrected compressor outflow air flow rate is used for the calculation according to the intercooler model M7. As a result, the cylinder inflow air amount calculated by the current model calculation is the compressor outflow before correction. This is smaller than the in-cylinder inflow air amount calculated when the air flow rate is used.

  On the other hand, if the intercooler pressure calculated by the current model calculation is lower than the intercooler pressure calculated by the previous model calculation, the difference ΔPi takes a negative value and the slope is a negative value. Since the correction amount Δmcm has a positive value, the corrected compressor outflow air flow rate is larger than the uncorrected compressor outflow air flow rate by the correction amount Δmcm. The corrected compressor outflow air flow rate is used for the calculation according to the intercooler model M7, and as a result, the in-cylinder inflow air amount calculated by the current model calculation is the compressor outflow before correction. It becomes larger than the in-cylinder inflow air amount calculated when the air flow rate is used.

  If the compressor outflow air flow rate is corrected in this way, the cylinder inflow air amount finally obtained by the model calculation matches the actual cylinder inflow air amount when it is used for controlling the operation of the internal combustion engine. Or at least not corrected, it is closer to the actual in-cylinder inflow air amount than the in-cylinder inflow air amount calculated.

  In the above-described example, whether or not the amount of change in the compressor outflow air flow rate is greater than a predetermined amount of change is determined based on the difference between the predicted throttle opening and the target throttle opening. In addition to this, as described in relation to the first embodiment, it may be performed based on the amount of change in the intake pipe pressure.

  Further, in place of or in addition to the above-described determination as a determination as to whether or not the change amount of the compressor outflow air flow rate is greater than a predetermined change amount, the intake air with respect to the intake pressure Pa described in connection with the first embodiment A determination similar to the determination using the ratio Pm / Pa of the tube pressure Pm may be employed. That is, the relationship between the ratio Pm / Pi of the intake pipe pressure Pm to the intercooler pressure Pi and the relationship between the throttle valve passing air flow rate mt is as shown in FIG. That is, when the throttle opening θ is constant and the pressure ratio Pm / Pi is smaller than the specific pressure ratio Rs, the throttle valve passing air flow rate is constant regardless of the pressure ratio. On the other hand, when the throttle opening is constant and the pressure ratio is larger than the specific pressure ratio Rs, the larger the pressure ratio, the smaller the throttle valve passing air flow rate. When the pressure ratio is constant, the throttle valve passing air flow rate is larger as the throttle opening is larger.

  Therefore, when the pressure ratio Pm / Pi increases beyond the specific pressure ratio Rs, the throttle valve passage air flow rate mt changes greatly even if the throttle opening θ is constant. Also, when the pressure ratio increases in a region larger than the specific pressure ratio, the throttle valve passing air flow rate greatly changes even if the throttle opening is constant. Conversely, even when the pressure ratio becomes smaller than the specific pressure ratio, even if the throttle opening is constant, the flow rate of air passing through the throttle valve changes greatly, and the pressure ratio is larger than the specific pressure ratio. Even when the throttle opening is constant, the throttle valve passing air flow rate greatly changes.

  In general, it can be said that when the flow rate of air passing through the throttle valve changes greatly, the flow rate of compressor outflow air also changes greatly. Therefore, when the pressure ratio Pm / Pi increases beyond the specific pressure ratio Rs between the previous model calculation time and the current model calculation time, or increases in a region larger than the specific pressure ratio. Alternatively, when the pressure becomes smaller than the specific pressure ratio, or when the pressure becomes smaller in the region larger than the specific pressure ratio, even if the throttle opening θ is constant, within a short period after the start of the current model calculation. It may be determined that the throttle valve passing air flow rate mt changes greatly, therefore the compressor inflow air flow rate also changes greatly, and therefore the in-cylinder inflow air amount also changes greatly. When it is determined that the compressor inflow air flow rate changes greatly, the cylinder inflow air flow rate is corrected by correcting the compressor inflow air flow rate as described above.

  In addition, instead of or in addition to the above-described determination, a determination based on the compressor rotational speed may be adopted as a determination as to whether or not the change amount of the compressor outflow air flow rate is larger than a predetermined change amount. That is, it can be said that the change amount of the compressor outflow air flow rate is large when the change amount of the compressor rotation speed is large. Therefore, the difference ΔNC (k) (= NC (k) −NC (k−1) between the compressor rotation speed NC (k−1) at the time of the previous model calculation and the compressor rotation speed NC (k) at the time of the current model calculation. ) Is larger than a predetermined rotation speed difference ΔNCs, it may be determined that the amount of change in the compressor outflow air flow is large.

  Further, the following determination may be adopted instead of or in addition to the above-described determination as to whether or not the change amount of the compressor outflow air flow rate is larger than a predetermined change amount. That is, a difference ΔPi of the intercooler pressure at the current model calculation time relative to the intercooler pressure at the previous model calculation time is calculated, and the difference ΔPi added to the intercooler pressure at the current model calculation time is used as a temporary intercooler pressure. calculate. This temporary intercooler pressure corresponds to the intercooler pressure that can be taken at the time of the next model calculation. Further, the difference ΔNC between the compressor speed at the time of the current model calculation and the compressor speed at the time of the current model calculation is calculated as the provisional compressor speed obtained by adding the difference ΔNC to the compressor speed at the time of the current model calculation. calculate. This temporary compressor rotational speed corresponds to the compressor rotational speed that can be taken at the next model calculation time.

  Here, with reference to FIG. 30, if the intercooler pressure at the time of the current model calculation is the pressure Pi1, and the compressor rotation speed at the time of the current model calculation is NC1, the compressor outflow air flow rate is the flow rate mcm1. . Here, assuming that the intercooler pressure at the time of the next model calculation is the provisional intercooler pressure Pi2, if the compressor rotation speed is the rotation speed NC2, the compressor outflow air flow rate is the compressor outflow air flow rate mcm1 at the current model calculation time. And the same flow rate. Therefore, if the temporary compressor rotational speed is the rotational speed NC2, the compressor outflow air flow rate does not change or at least does not change significantly between the current model calculation time and the next model calculation time. On the other hand, if the temporary compressor rotational speed is the rotational speed NC3 larger than the rotational speed NC2, the compressor outflow air flow rate increases up to the flow rate mcm2, so that it greatly changes between the current model computation time and the next model computation time. Become. On the contrary, even if the temporary compressor rotational speed is smaller than the rotational speed NC2, the compressor outflow air flow rate greatly changes between the current model calculation time and the next model calculation time.

  Therefore, the temporary intercooler pressure and the temporary compressor speed are calculated as described above, and even if the intercooler pressure becomes the temporary intercooler pressure, the compressor outflow air flow rate is equal to the flow rate at the time of the current model calculation. Is obtained as the reference compressor speed. Then, when the difference between the reference compressor rotational speed and the temporary compressor rotational speed is larger than a predetermined rotational speed difference, it is determined that the change amount of the compressor outflow air flow rate is larger than the predetermined change amount. Also good.

  When this determination is adopted, the compressor outflow air flow rate is corrected so that the compressor outflow air flow rate becomes larger if the temporary compressor rotation number is larger than the reference compressor rotation number. On the other hand, if the temporary compressor rotation speed is smaller than the reference compressor rotation speed, the compressor outflow air flow rate is corrected so that the compressor outflow air flow rate becomes small.

  Further, the following determination may be adopted instead of or in addition to the above-described determination as to whether or not the change amount of the compressor outflow air flow rate is larger than a predetermined change amount. That is, the compressor 91a is rotated when the exhaust turbine 91b is rotated by the exhaust gas. Therefore, if the energy that the exhaust turbine 91b receives from the exhaust gas is equal to the energy that the compressor 91a gives to the air, the compressor speed does not change. However, if the energy that the compressor 91a gives to the air is smaller than the energy that the exhaust turbine 91b receives from the exhaust gas, the compressor rotation speed increases. Conversely, the energy that the compressor 91a gives to the air than the energy that the exhaust turbine 91b receives from the exhaust gas. If this is larger, the compressor speed becomes smaller.

  Therefore, when the absolute value of the difference between the energy received by the exhaust turbine 91b from the exhaust gas and the energy given to the air by the compressor 91a is larger than the predetermined energy difference, the change amount of the compressor outflow air flow rate is determined in advance. You may make it judge that it is larger than.

  If this determination is adopted, the compressor outflow air flow rate is corrected so that the compressor outflow air flow rate becomes larger if the energy that the compressor 91a gives to the air is smaller than the energy received by the exhaust turbine 91b from the exhaust gas. On the other hand, if the energy that the compressor 91a gives to the air is larger than the energy that the exhaust turbine 91b receives from the exhaust gas, the compressor outflow air flow rate is corrected so that the compressor outflow air flow rate becomes smaller.

  In the above-described example, the difference between the intercooler pressure calculated by the previous model calculation and the intercooler pressure calculated by the current model calculation is used as a correction amount for the compressor outflow air flow rate. The value calculated as described above may be used as a correction amount for the compressor outflow air flow rate. That is, the difference Δmcm (k) (= mcm () between the compressor outflow air flow rate mcm (k) before correction calculated by the current model calculation and the compressor outflow air flow rate mcm (k-1) calculated by the previous model calculation. k) -mcm (k-1)). The difference Δmcm (k) calculated here is considered to correspond to a change amount of the compressor outflow air flow rate that will change from the start time of the current model calculation to the start time of the next model calculation. Therefore, if this difference Δmcm (k) is added to the compressor outflow air flow rate mcm (k) calculated by the current model calculation, the compressor outflow air flow rate thus obtained is at least the actual time at the start of the next model calculation. It can be said that it corresponds to the compressor outflow air flow rate.

  Therefore, in this example, correction is performed by adding the difference Δmcm (k) calculated as described above to the compressor outflow air flow rate calculated by the current model calculation.

  According to this, if the uncorrected compressor outflow air flow calculated by the current model calculation is larger than the uncompressed compressor outflow air flow calculated by the previous model calculation, the difference Δmcm takes a positive value. The compressor outflow air flow rate becomes larger by the difference mcm than the compressor outflow air flow rate before correction. The corrected compressor outflow air flow rate is used for the calculation according to the intercooler model M7, and as a result, the in-cylinder inflow air amount calculated by the current model calculation is the compressor outflow before correction. It becomes larger than the in-cylinder inflow air amount calculated when the air flow rate is used.

  On the other hand, if the compressor outflow air flow before correction calculated by the current model calculation is smaller than the compressor outflow air flow calculated by the previous model calculation, the above difference mcm (k) takes a negative value and is corrected. The subsequent compressor outflow air flow rate is smaller than the uncorrected compressor outflow air flow rate by the difference mcm (k). Then, the corrected compressor outflow air flow rate is used for the calculation according to the intercooler model M7. As a result, the cylinder inflow air amount calculated by the current model calculation is the compressor outflow before correction. This is smaller than the in-cylinder inflow air amount calculated when the air flow rate is used.

  Even if the compressor outflow air flow rate is corrected in this way, the cylinder inflow air amount finally obtained by the model calculation is the actual cylinder inflow at the time when the cylinder inflow air amount is used for controlling the operation of the internal combustion engine. It is closer to the actual in-cylinder inflow air amount than the in-cylinder inflow air amount calculated when the air amount matches or at least is not corrected.

  The correction method for the in-cylinder inflow air amount in the first embodiment may be applied to the correction for the in-cylinder inflow air amount in the second embodiment. In this case, in the first embodiment, the portion using the intake air pressure Pa uses the intercooler pressure Pi, and the portion using the intake air temperature Ta uses the intercooler temperature Ti.

  Next, an example of a routine for calculating the in-cylinder inflow air amount according to the second embodiment will be described. An example of this routine is shown in FIGS. The calculation routine according to the electronic control throttle valve model M1 is the same as the routine shown in FIG.

  The routines shown in FIG. 27 and FIG. 28 are routines for executing calculations according to the models M2 to M7, and are executed at the predetermined time intervals ΔT2. When this routine is started, first, at step 301, the target throttle opening θt stored in the ROM 72 by execution of the routine of FIG. 13 is a time point later than the current model calculation time point. The target throttle opening θt at the time closest to the calculation time is read as the target throttle opening θt (k−1) used for the current model calculation. Next, in step 302, among the predicted throttle opening θe stored in the ROM 72 by the execution of the routine of FIG. 13 as well, a prediction is made at a time point that is later in time than the current model calculation time point and closest to the calculation time point. The throttle opening degree θe is read as the predicted throttle opening degree θe (k−1) used for the current model calculation.

  Next, the routine proceeds to step 303 to step 305 in which calculation according to the throttle model M2 is executed. In step 303, the value C (θ) (k-1) · A (θ) (k−) is calculated from the map Mca (see FIG. 5) based on the predicted throttle opening θe (k−1) read in step 302. 1) is required. Next, at step 304, a value Pm (k-1) / Pi (k-) obtained by dividing the intake pipe pressure Pm (k-1) at the previous model calculation time by the intercooler pressure Pi (k-1) at the previous model calculation time. Based on 1), the value Φ (Pm (k−1) / Pi (k−1)) is obtained from the map MΦ (see FIG. 19). Next, at step 305, the value C (θ) (k-1) · A (θ) (k-1) obtained at step 303 and the value Φ (Pm (k-1) / Pi (k-1)), the intake pipe pressure Pm (k-1) at the time of the previous model calculation, and the intercooler temperature Ti (k-1) at the time of the previous model calculation, A throttle valve passage air flow rate mt (k-1) is calculated.

  Next, the routine proceeds to step 306 to step 308 in which the calculation according to the intake valve model M3 is executed. That is, in step 306, the value c (k-1) is obtained from the map Mc (see FIG. 7) based on the engine speed NE (k-1) and the intake valve opening / closing timing VT (k-1) at the time of the current model calculation. Desired. Next, at step 307, the value d (k-1) is obtained from the map Md (see FIG. 8) based on the engine speed NE (k-1) and the intake valve opening / closing timing VT (k-1) at the time of the current model calculation. Desired. Next, at step 308, the value c (k-1) obtained at step 306, the value d (k-1) obtained at step 307, and the intercooler temperature Ti (k-1) at the previous model calculation time. ), The intake pipe temperature Tm (k-1) at the time of the previous model calculation, and the intake pipe pressure Pm (k-1) at the time of the previous model calculation, according to the above model equation 11, (k-1) is calculated.

  Next, in step 309 in FIG. 28, the difference Δθ (k−1) between the target throttle opening θt (k−1) read in step 301 and the predicted throttle opening θe (k−1) read in step 302 above. ) Is larger than a predetermined opening degree difference Δθs (| Δθ (k−1) |> Δθs). Here, when it is determined that | Δθ (k−1) |> Δθs, that is, when it is determined that the compressor outflow air flow rate greatly changes between the current model calculation time and the next model calculation time, the routine is The process proceeds to Steps 310 to 312 for performing a calculation according to the compressor model M5 and correcting the compressor outflow air flow rate calculated by the calculation. That is, in step 310, the pressure ratio Pm (k-1) / Pi (k-1) of the intake pipe pressure Pm (k-1) at the previous model calculation time to the intercooler pressure Pi (k-1) at the previous model calculation time. ) And the compressor rotation speed NC (k-1) at the time of the previous model calculation, the compressor outflow air flow rate mcm (k-1) is obtained from the map Mmcm (see FIG. 21). Next, at step 311, the gradient dmcm from the map Mmcm (see FIG. 25) based on the compressor rotational speed NC (k-1) at the previous model calculation time and the intercooler pressure Pi (k-1) at the previous model calculation time. (k-1) is required. Next, at step 312, the difference ΔPi (k-1) (= Pi (k-) between the intercooler pressure Pi (k-1) at the time of the current model calculation and the intercooler pressure Pi (k-2) at the time of the previous model calculation. 1) -Pi (k-2)) is calculated. Next, in step 313, the difference ΔPi (k−1) calculated in step 312 is multiplied by the slope dmcm (k−1) obtained in step 311 to thereby correct the correction amount Δmcm (k−1) for the compressor outflow air flow rate. Is calculated. Next, in step 314, a correction is performed in which the correction amount Δmcm (k-1) calculated in step 313 is added to the compressor outflow air flow rate mcm (k-1) calculated in step 310, and the routine is executed by the intercooler. Proceed to step 315 of FIG. 29 to execute the calculation according to the model M7. Therefore, according to this, when it is determined in step 309 that the compressor outflow air flow rate changes greatly between the current model calculation time and the next model calculation time, the corrected compressor outflow air flow rate is corrected in the model calculation in step 315 and subsequent steps. As a result, the in-cylinder inflow air amount calculated by the current model calculation is corrected.

  On the other hand, when it is determined in step 309 that | Δθ (k−1) | ≦ Δθs, that is, it is determined that the compressor outflow air flow rate does not change significantly between the current model calculation time and the next model calculation time. If so, the routine proceeds to step 322 where a calculation according to the compressor model M5 is executed. That is, in step 322, the pressure ratio Pm (k-1) / Pi (k-1) of the intake pipe pressure Pm (k-1) at the previous model calculation time to the intercooler pressure Pi (k-1) at the previous model calculation time. ) And the previous compressor rotation speed NC (k-1), the compressor outflow air flow rate mcm (k-1) is obtained from the map Mmcm (see FIG. 21), and the routine calculates in accordance with the intercooler model M7. The process proceeds to step 315 of FIG. Therefore, according to this, when it is determined in step 309 that the compressor outflow air flow rate does not change significantly between the current model calculation time and the next model calculation time, the compressor that has not been corrected in the model calculation in step 315 and subsequent steps. The outflow air flow rate is used, and as a result, the cylinder inflow air amount calculated by the current model calculation is not corrected.

  In step 315, the compressor outflow air flow rate mcm (k-1) calculated in step 314 or step 322, the throttle valve passage air flow rate mt (k-1) calculated in step 305, and the previous model calculation. The intercooler pressure Pi (k) and the intercooler temperature Ti (k) according to the above model formula 12 and model formula 13 based on the intake air temperature Ta (k-1) at the time point and the compressor applied energy Ec calculated according to the above formula 19. ) Is calculated.

  Next, the routine proceeds to step 313 of FIG. 29 in which the calculation according to the intake pipe model M4 is executed. That is, in step 313, the throttle valve passage air flow rate mt (k-1) calculated in step 305, the cylinder inflow air flow rate mc (k-1) calculated in step 308, and the current model calculation time point. Based on the intercooler temperature Ti (k-1), the intake pipe pressure Pm (k) and the intake pipe temperature Tm (k) are calculated in accordance with the model formula 31 and the model formula 32.

  Next, the routine proceeds to step 317 to step 321 for executing calculation according to the intake valve model M5. That is, in step 317, the value c (k-1) is obtained from the map Mc (see FIG. 7) based on the engine speed NE (k-1) and the intake valve opening / closing timing VT (k-1) at the time of the current model calculation. Desired. Next, at step 318, a value d (k-1) is obtained from the map Md (see FIG. 8) based on the engine speed NE (k-1) and the intake opening / closing timing VT (k-1) at the time of the current model calculation. It is done. Next, at step 319, the value c (k-1) obtained at step 317, the value d (k-1) obtained at step 318, and the intake pipe pressure Pm (k) calculated at step 316. In-cylinder inflow air flow rate mc (k) according to the model equation 33 based on the intake pipe temperature Tm (k) calculated in step 316 and the intercooler temperature Ti (k) calculated in step 315. Is calculated. Next, at step 320, the intake valve opening time Tint (k) is calculated based on the engine speed NE (k-1) and the intake valve opening / closing timing VT (k-1) at the time of the current model calculation. Next, in step 321, the cylinder inflow air amount KLfwd (in accordance with the above equation 34 based on the cylinder inflow air flow rate mc (k) calculated in step 319 and the intake valve opening time Tint calculated in step 320. k) is calculated and the routine ends.

  In the above-described embodiment, calculation is performed by model calculation in accordance with a change amount of a specific parameter value (for example, change amount of the air flow rate through the throttle valve) during a period from the previous model calculation time point to the current model calculation time point. The amount of air flowing into the cylinder is corrected. That is, it is considered that the parameter value changes from the current model calculation time point to the next model calculation time point by an amount equal to the change amount of a specific parameter value from the previous model calculation time point to the current model calculation time point. ing. Therefore, in the above-described embodiment, the corrected in-cylinder inflow air amount becomes a value that matches or at least close to the in-cylinder inflow air amount at the time of the next model calculation.

  However, the amount of change in a specific parameter value during the period from the previous model calculation time to the current model calculation time is not used for correction of the in-cylinder inflow air amount. Alternatively, the change amount of a specific parameter value may be used, or conversely, the change amount of a specific parameter value during a period longer than the above period may be used. In this case, the corrected in-cylinder inflow air amount is a value that matches or is at least close to the in-cylinder inflow air amount when it has elapsed from the time of the current model calculation for the period that is the reference for calculating the amount of change in the parameter value. It has become. As an example, even if a period until the cylinder inflow air amount calculated by the current model calculation is actually used for control of the operation of the internal combustion engine is adopted as a reference period for calculating the correction amount of the parameter value Good. In this case, the calculated in-cylinder inflow air amount is equal to or at least close to the actual in-cylinder inflow air amount when it is actually used for controlling the operation of the internal combustion engine.

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 21 ... Cylinder, 25 ... Combustion chamber, 31 ... Intake port, 32 ... Intake valve, 34 ... Exhaust port, 35 ... Exhaust valve, 39 ... Fuel injection valve, 41 ... Intake branch pipe, 42 ... Surge tank , 43 ... Intake duct, 44 ... Air filter, 45 ... Intercooler, 46 ... Throttle valve, 46a ... Throttle valve drive actuator, 51 ... Exhaust pipe, 61 ... Pressure sensor, 62 ... Temperature sensor, 63 ... Compressor speed sensor , 65 ... Crank position sensor, 66 ... Accelerator opening sensor, 67 ... Accelerator pedal, 70 ... Electric control device, 91 ... Supercharger, 91a ... Compressor, 91b ... Turbine

Claims (20)

  The amount of air sucked into the combustion chamber during the intake stroke based on the model equation for calculating the amount of air flowing into the cylinder based on the mass conservation law and the energy conservation law for the air sucked into the combustion chamber. An amount of air that is actually taken into a combustion chamber during an intake stroke in a control device for an internal combustion engine that is calculated as a calculated value of the air amount and controls the operation of the internal combustion engine based on the calculated value of the in-cylinder inflow air amount Is the actual value of the cylinder inflow air amount, the actual value of the cylinder inflow air amount when a predetermined time has elapsed after the calculation of the cylinder inflow air amount is started is The calculation is made as a predicted value of the in-cylinder inflow air amount at the start of the calculation of the amount, and the difference between the predicted value of the inflow in the cylinder and the actual value of the inflow cylinder in the cylinder at the start of the calculation of the inflow cylinder is calculated. When the calculation of the inflow air amount starts, the change in the inflow amount of the cylinder is expected to change. When the predicted change value of the cylinder inflow air amount is larger than the predetermined change prediction value, the calculated value of the cylinder inflow air amount is determined in accordance with the predicted change value of the cylinder inflow air amount. A control apparatus for an internal combustion engine, wherein the control of the internal combustion engine is controlled based on the corrected calculated value of the in-cylinder inflow air amount.   A throttle valve is arranged in the intake passage connected to the combustion chamber, and the throttle valve opening at the start of calculation of the inflow of cylinder air and the throttle to be targeted at the start of calculation of the inflow of cylinder air When the difference between the opening degree of the valve and the opening degree difference is larger than a predetermined opening degree difference, it is determined that the predicted change value of the in-cylinder inflow air amount is larger than the predetermined change predicted value. The control apparatus for an internal combustion engine according to claim 1.   When the pressure in the intake passage downstream of the throttle valve is referred to as throttle valve downstream pressure, the throttle valve downstream pressure when the predetermined time has elapsed since the calculation of the in-cylinder inflow air amount is started. Calculated as a predicted value of the throttle valve downstream pressure at the start of calculation of the cylinder inflow air amount, and the difference between the predicted value of the throttle valve downstream pressure and the throttle valve downstream pressure at the start of calculation of the cylinder inflow air amount Calculated as a change amount of the throttle valve downstream pressure at the start of the calculation of the inflow air amount, and when the change amount of the throttle valve downstream pressure is larger than a predetermined pressure change amount, 3. The control device for an internal combustion engine according to claim 2, wherein the control device is determined to be larger than a predetermined change prediction value.   When the pressure in the intake passage downstream of the throttle valve is referred to as throttle valve downstream pressure and the flow rate of air passing through the throttle valve is referred to as throttle valve passage air flow rate, the throttle valve downstream pressure is higher than a specific pressure. Sometimes, even if the throttle valve opening is constant, the higher the throttle valve downstream pressure, the smaller the throttle valve passing air flow rate, and the calculation of the in-cylinder inflow air amount starts until the predetermined time elapses. In the meantime, when it is judged that the throttle valve downstream pressure becomes higher than the specific pressure or the throttle valve downstream pressure becomes higher in a region higher than the specific pressure, or the throttle valve downstream pressure exceeds the specific pressure. When it is determined that the pressure is low or the pressure downstream of the throttle valve is low in a region higher than the specific pressure, the cylinder The control device according to claim 2 or 3 changes predicted value of the inflow air quantity, characterized in that it is determined that the larger than a predetermined variation predicted value.   When the pressure in the intake passage downstream of the throttle valve is referred to as throttle valve downstream pressure and the flow rate of air passing through the throttle valve is referred to as throttle valve passage air flow rate, the throttle valve downstream pressure is higher than a specific pressure. Sometimes even if the throttle valve opening is constant, the higher the throttle valve downstream pressure is, the smaller the throttle valve passing air flow rate is, and if the throttle valve downstream pressure is constant, the larger the throttle valve opening is, the larger the throttle valve passing air flow rate is. The throttle valve opening, the throttle valve downstream pressure, and the throttle valve passage air flow rate at the start of calculation of the in-cylinder inflow air amount are respectively expressed as a reference throttle opening, a reference throttle valve downstream pressure, and a reference throttle valve passage air flow rate. The opening of the throttle valve when the predetermined time has elapsed The throttle valve passing air flow rate is larger than the reference throttle opening, the throttle valve downstream pressure is higher than the reference throttle valve downstream pressure, and the throttle valve passing air flow rate is the reference throttle at the throttle valve opening when the predetermined time has elapsed. When it is determined that the throttle valve downstream pressure is higher when the predetermined time elapses than the throttle valve downstream pressure equal to the valve passing air flow rate, the predicted change value of the cylinder inflow air amount is determined in advance. 5. The change prediction value of the in-cylinder inflow air amount is determined to be larger than the predetermined change prediction value, and is determined to be larger than the predetermined change prediction value. A control apparatus for an internal combustion engine as set forth in claim 1.   When a throttle valve is disposed in the intake passage connected to the combustion chamber, and the pressure in the intake passage downstream of the throttle valve is referred to as the throttle valve downstream pressure, calculation of the in-cylinder inflow air amount is started. The throttle valve downstream pressure when the predetermined time elapses from the time is calculated as a predicted value of the throttle valve downstream pressure at the start of calculation of the in-cylinder inflow air amount, and the predicted value of the throttle valve downstream pressure and in-cylinder inflow air are calculated The difference from the throttle valve downstream pressure at the start of the calculation of the amount is calculated as a change amount of the throttle valve downstream pressure at the start of the calculation of the cylinder inflow air amount, and the change amount of the throttle valve downstream pressure is a predetermined pressure change 2. The internal combustion engine control according to claim 1, wherein when it is larger than the amount, it is determined that a predicted change value of the in-cylinder inflow air amount is larger than the predetermined predicted change value. Apparatus.   A throttle valve is disposed in the intake passage connected to the combustion chamber, the pressure in the intake passage downstream of the throttle valve is referred to as the throttle valve downstream pressure, and the flow rate of the air passing through the throttle valve is the throttle valve passing air. When the throttle valve downstream pressure is higher than a specific pressure, the throttle valve passing air flow rate decreases as the throttle valve downstream pressure increases even if the throttle valve opening is constant. The throttle valve downstream pressure becomes higher than the specific pressure or the throttle valve downstream pressure is higher in the region where the predetermined pressure elapses after the predetermined time elapses after the calculation is started. Or when the throttle valve downstream pressure is lower than the specific pressure or the throttle valve downstream pressure is The change predicted value of the in-cylinder inflow air amount is determined to be larger than the predetermined change predicted value when it is determined that the pressure is lower in a region higher than a predetermined pressure. Control device for internal combustion engine.   A throttle valve is disposed in the intake passage connected to the combustion chamber, the pressure in the intake passage downstream of the throttle valve is referred to as the throttle valve downstream pressure, and the flow rate of the air passing through the throttle valve is the throttle valve passing air. When the flow rate is referred to as a flow rate, when the throttle valve downstream pressure is higher than a specific pressure, the throttle valve passing air flow rate decreases and the throttle valve downstream pressure decreases as the throttle valve downstream pressure increases even if the throttle valve opening is constant. If it is constant, the larger the throttle valve opening, the larger the throttle valve passing air flow rate, and the throttle valve opening, throttle valve downstream pressure, and throttle valve passing air flow rate at the start of calculation of in-cylinder inflow air will be used as references. When referred to as throttle opening, throttle valve downstream pressure, and reference throttle valve passage air flow rate, When the predetermined time has elapsed, the throttle valve opening is larger than the reference throttle opening, the actual throttle downstream pressure is higher than the reference throttle valve downstream pressure, and the predetermined time has elapsed. It is determined that the throttle valve downstream pressure when the predetermined time elapses is higher than the throttle valve downstream pressure at which the throttle valve passage air flow rate becomes equal to the reference throttle valve passage air flow rate at the opening of the throttle valve. When it is determined that the predicted change value of the in-cylinder inflow air amount is larger than the predetermined change prediction value, the predicted change value of the in-cylinder air flow amount is greatly reduced from the predetermined change prediction value. 2. The control device for an internal combustion engine according to claim 1, wherein   A throttle valve is disposed in the intake passage connected to the combustion chamber, and the cylinder inflow air amount calculation model equation calculates the flow rate of air passing through the throttle valve as a calculated value of the throttle valve passage air flow rate. A valve passing air flow rate calculation model formula is included, and when the predicted change value of the in-cylinder inflow air amount is determined to be larger than the predetermined change predicted value, it is calculated by the throttle valve passing air flow rate calculation model formula The calculated value of the in-cylinder inflow air amount calculated by the in-cylinder inflow air amount calculation model formula is obtained by correcting the calculated value of the throttle valve passage air flow rate in accordance with the predicted change value of the in-cylinder inflow air amount. 2. The control apparatus for an internal combustion engine according to claim 1, wherein the control is performed according to a predicted change value of the inflow air amount.   When the flow rate of air passing through the throttle valve is referred to as a throttle valve passing air flow rate, the throttle valve passing air flow rate when the predetermined time has elapsed since the calculation of the in-cylinder inflow air amount is started. Calculated as the predicted value of the throttle valve passing air flow rate at the start of calculation of the cylinder inflow air amount, and the difference between the predicted value of the throttle valve passing air flow rate and the throttle valve passing air flow rate at the start of calculation of the cylinder inflow air amount Calculated as a predicted change value of the air flow rate through the throttle valve at the start of calculation of the in-cylinder inflow air amount, and when it is determined that the predicted change in the in-cylinder inflow air amount is greater than the predetermined change predicted value By correcting the calculated value of the throttle valve passing air flow rate according to the predicted change value of the throttle valve passing air flow rate, the calculated value of the throttle valve passing air flow rate can The control apparatus according to claim 9, characterized in that it is corrected in accordance with the change predicted value of the amount.   When the pressure in the intake passage downstream of the throttle valve is referred to as throttle valve downstream pressure, the throttle valve downstream pressure when the predetermined time has elapsed since the calculation of the in-cylinder inflow air amount is started. Calculated as a predicted value of the throttle valve downstream pressure at the start of the inflow air amount calculation process, and the difference between the predicted value of the throttle valve downstream pressure and the throttle valve downstream pressure at the start of the calculation of the inflow amount of the cylinder Calculated as a change amount of the throttle valve downstream pressure at the start of the calculation of the inflow air amount, and when it is determined that the predicted change value of the inflow amount in the cylinder is larger than the predetermined change prediction value, Is corrected according to the amount of change in the throttle valve downstream pressure, so that the calculated value of the throttle valve passage air flow rate becomes the predicted change value of the throttle valve passage air flow rate. Flip the control apparatus for an internal combustion engine according to claim 10, characterized in that it is corrected.   The throttle valve opening when the predetermined time has elapsed since the calculation of the in-cylinder inflow air amount is started is calculated as a predicted value of the throttle opening at the start of the in-cylinder inflow air amount calculation. The difference between the predicted value of the opening and the opening of the throttle valve at the start of the calculation of the cylinder inflow air amount is calculated as the predicted change in the throttle opening at the start of the calculation of the cylinder inflow air amount. When it is determined that the predicted change in amount is larger than the predetermined predicted change value, the calculated value of the air flow rate through the throttle valve is corrected in accordance with the predicted change in throttle opening, thereby passing the throttle valve. The control device for an internal combustion engine according to claim 10 or 11, wherein the calculated value of the air flow rate is corrected according to a predicted change value of the air flow rate through the throttle valve.   When it is determined that the predicted change value of the in-cylinder inflow air amount is larger than the predetermined change prediction value, the predicted change value of the in-cylinder inflow air amount is larger than the predetermined change prediction value. When it is determined to increase, the calculated value of the in-cylinder inflow air amount is corrected so as to increase. On the other hand, when the predicted change value of the in-cylinder inflow air amount is determined to be larger than the predetermined change prediction value When it is determined that the predicted change value of the in-cylinder inflow air amount is greatly decreased from the predetermined change prediction value, the calculated value of the in-cylinder inflow air amount is corrected so as to be reduced. The control device for an internal combustion engine according to any one of claims 1 to 12.   The difference between the opening degree of the throttle valve at the start of calculation of the inflow amount of cylinder air and the opening degree of the throttle valve to be targeted at the start of calculation of the inflow amount of cylinder air is larger than a predetermined opening degree difference. The control device for an internal combustion engine according to any one of claims 9 to 13, wherein a predicted change value of the in-cylinder inflow air amount is sometimes determined to be larger than the predetermined predicted change value. .   When the pressure in the intake passage downstream of the throttle valve is referred to as throttle valve downstream pressure, the throttle valve downstream pressure when the predetermined time has elapsed since the calculation of the in-cylinder inflow air amount is started. Calculated as a predicted value of the throttle valve downstream pressure at the start of the calculation of the inflow air amount, and the difference between the predicted value of the throttle valve downstream pressure and the throttle valve downstream pressure at the start of the calculation of the inflow amount of the cylinder The amount of change in the downstream pressure of the throttle valve is calculated as the amount of change in the downstream pressure of the throttle valve at the start of calculation of the air amount, and when the amount of change in the downstream pressure of the throttle valve is larger than the predetermined amount of change in pressure, The control device for an internal combustion engine according to any one of claims 9 to 14, wherein the control device is determined to be larger than a predetermined change prediction value.   When the pressure in the intake passage downstream of the throttle valve is referred to as throttle valve downstream pressure and the flow rate of air passing through the throttle valve is referred to as throttle valve passage air flow rate, the throttle valve downstream pressure is higher than a specific pressure. Sometimes, even if the throttle valve opening is constant, the higher the throttle valve downstream pressure, the smaller the throttle valve passing air flow rate, and the calculation of the in-cylinder inflow air amount starts until the predetermined time elapses. In the meantime, when it is judged that the throttle valve downstream pressure becomes higher than the specific pressure or the throttle valve downstream pressure becomes higher in a region higher than the specific pressure, or the throttle valve downstream pressure exceeds the specific pressure. When it is determined that the pressure is low or the pressure downstream of the throttle valve is low in a region higher than the specific pressure, the cylinder The control device according to any one of claims 9 to 15 which changes predicted value of the inflow air quantity, characterized in that it is determined that the larger than a predetermined variation predicted value.   When the pressure in the intake passage downstream of the throttle valve is referred to as a throttle valve downstream pressure and the flow rate of air passing through the throttle valve is referred to as a throttle valve passing air flow rate, the throttle valve downstream pressure is higher than a specific pressure. Sometimes even if the throttle valve opening is constant, the higher the throttle valve downstream pressure is, the smaller the throttle valve passing air flow rate is. If the throttle valve downstream pressure is constant, the larger the throttle valve opening is, the larger the throttle valve passing air flow rate is. In many cases, the throttle valve opening, the throttle valve downstream pressure, and the throttle valve passage air flow rate at the start of calculation of the cylinder inflow air amount are respectively referred to as the reference throttle opening amount, the reference throttle valve downstream pressure, and the reference throttle valve passage air flow amount. When the predetermined time has elapsed, the opening of the throttle valve The throttle valve passing air flow rate is larger than the reference throttle opening, the throttle valve downstream pressure is higher than the reference throttle valve downstream pressure, and the throttle valve passing air flow rate is the reference throttle at the opening of the throttle valve when the predetermined time has elapsed. When it is determined that the throttle valve downstream pressure is higher when the predetermined time has passed than the throttle valve downstream pressure equal to the valve-passing air flow rate, the predicted change value of the in-cylinder inflow air amount is determined in advance. 17. The method according to claim 9, wherein the change prediction value is determined to be larger than the predetermined change prediction value, and the change prediction value of the in-cylinder inflow air amount is determined to decrease more than the predetermined change prediction value. A control device for an internal combustion engine according to claim 1.   18. The calculation of the in-cylinder inflow air amount is performed at a predetermined time interval, and the predetermined time is equal to the predetermined time interval. A control apparatus for an internal combustion engine according to claim 1.   The calculated value of the cylinder inflow air amount calculated by calculating the cylinder inflow air amount after the calculation of the cylinder inflow air amount is started for the predetermined time is used for controlling the operation of the internal combustion engine. The control device for an internal combustion engine according to any one of claims 1 to 17, characterized in that the time is equal to the time until.   An internal combustion engine includes a supercharger, and the in-cylinder inflow air amount calculation model formula calculates a flow rate of air passing through the compressor of the supercharger as a calculated value of the compressor pass air flow rate. And calculating the compressor passage air flow rate calculated by the compressor passage air flow rate calculation model formula when it is determined that the change prediction value of the in-cylinder inflow air amount is larger than the predetermined change prediction value. The calculated value of the cylinder inflow air amount calculated by the cylinder inflow air amount calculation model equation is corrected to the change prediction value of the cylinder inflow air amount by correcting the value according to the predicted change value of the cylinder inflow air amount. The control device for an internal combustion engine according to any one of claims 1 to 19, wherein the control device is corrected accordingly.

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