JP2007187064A - Internal combustion engine control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal combustion engine control device for estimating the amount of intake air with high accuracy while considering a change of a throttle flow path area in the condition of transient operation when predicting and estimating the amount of intake air during closing an intake valve in a cylinder to be controlled prior to a crank angle before starting the injection of fuel. <P>SOLUTION: The internal combustion engine control device comprises an intake air amount predicting and estimating means 7 using upstream pressure and downstream pressure in a throttle valve 1, a flow path area, an engine speed, a cylinder capacity and an intake air temperature for predicting and estimating the amount of intake air during closing the intake valve 3 in the cylinder to be controlled before starting the injection of fuel, a flow path area detecting means for detecting the flow path area of the throttle valve 1, and a flow path area predicting and estimating means 7 for predicting and estimating the flow path area of the throttle valve 1 during a time from starting the prediction and estimation of the amount of intake air to completing the closing of the intake valve. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention provides an internal combustion engine control device including an intake air amount control means for controlling an intake air amount to an internal combustion engine (engine). The present invention relates to an internal combustion engine control apparatus that estimates an intake air amount sucked into a cylinder before an injection start timing for starting fuel injection.

  2. Description of the Related Art Conventionally, in an internal combustion engine control apparatus, a technique is known in which various sensors such as a pressure sensor and an air flow sensor are installed, and an intake air amount into a cylinder is calculated based on detection values of the various sensors. However, in this case, the provision of sensors increases the cost, and particularly in a multiple throttle system in which a throttle is installed for each cylinder, it is necessary to install the sensors for each cylinder, which further increases the cost. .

In view of this, an internal combustion engine controller that controls the fuel injection amount by estimating the intake air amount into the cylinder without using a pressure sensor or an air flow sensor has been proposed (for example, see Patent Document 1).
In the conventional device described in Patent Document 1, the throttle valve, the intake valve, and the exhaust valve are regarded as orifices, and the flow path area of the orifice and the pressures on the upstream side and the downstream side of the orifice are used to calculate the hydrodynamic equation. Based on the above, the amount of air passing through the orifice portion (flow rate through the orifice) is estimated and calculated.

In addition, in the conventional device described in Patent Document 1, a new throttle downstream pressure is estimated and calculated from the estimated throttle portion passage flow rate and intake valve passage flow rate, and newly calculated from the intake valve passage flow rate and the exhaust valve passage flow rate. The in-cylinder pressure is estimated and calculated, and used for the next estimation calculation of each passing flow rate.
Hereinafter, the estimation calculation is sequentially performed according to the crank angle, the throttle downstream pressure and the cylinder pressure are estimated, and the intake air flow amount into the cylinder is integrated to estimate the intake air amount. Thus, the fuel amount control is performed by estimating the intake air amount into the cylinder without using a pressure sensor or an air flow sensor.

By the way, in general, the injection start timing for starting the fuel injection to the control target cylinder of the internal combustion engine takes into account the fuel suction time into the cylinder and the time required for the atomization of the fuel in the control target cylinder. It is set about two strokes before the intake valve closing completion time when the intake valve is fully closed.
This indicates that it is necessary to estimate the amount of intake air into the cylinder approximately two strokes ahead of the injection start timing for the cylinder to be controlled.

However, in Patent Document 1, the pressure on the downstream side of the throttle (intake air amount control means) (hereinafter referred to as “throttle downstream pressure”), the in-cylinder pressure based on the crank angle (rotation reference position) of the internal combustion engine. , And the intake air inflow / outflow amount into the cylinder is estimated in real time.
Therefore, according to Patent Document 1, as the intake air amount used for fuel injection control, for example, the “intake air amount of other cylinders” that has completed the intake stroke before the control target cylinder completes the intake stroke needs to be used. There is.

Here, referring to FIGS. 35 and 36, the fuel injection control by the conventional device as referred to in Patent Document 1 will be described.
FIG. 35 is an explanatory diagram showing a stroke table of each cylinder (first cylinder, third cylinder, fourth cylinder, and second cylinder) in a four-cylinder four-cycle engine, with the horizontal axis representing time and the vertical axis representing cylinder number. Show.
FIG. 36 is an explanatory diagram showing the characteristics of the intake air amount during transient operation by the fuel injection control of FIG. 35, where the horizontal axis shows time and the vertical axis shows the intake air amount.

In FIG. 35, “intake”, “pressure”, “expansion”, and “exhaust” indicate “intake stroke”, “compression stroke”, “expansion stroke”, and “exhaust stroke”, respectively. The injection timing is shown.
The white arrows connecting the strokes indicate the reference state of the intake air amount used for calculating the fuel injection amount. Α, β, and γ are the fuel injection timing of the fourth cylinder and the intake air of the fourth cylinder, respectively. The stroke and the intake stroke of the first cylinder are shown.

In FIG. 36, the solid characteristic curve indicates the intake air amount used for calculating the fuel injection amount, the broken characteristic curve indicates the actual intake air amount, and the one-dot chain line characteristic curve indicates the first characteristic curve. The intake air amount calculated using only the intake air amount estimating means (described later) is shown.
As can be seen from the interrelationships between the intake air amounts in FIG. 36, during the transient operation in which the intake air amount changes suddenly (for example, rapidly increases), the first intake air amount with respect to the actual intake air amount (broken line). The intake air amount (one-dot chain line) calculated using only the estimation means is a small value, and the intake air amount (solid line) used for the fuel injection control of the conventional device is a smaller value.

First, referring to FIG. 35, fuel injection control by the conventional device will be described by taking as an example a case where attention is paid to the fuel injection timing α of the fourth cylinder.
As described above, for example, the fuel injected at the fuel injection timing α of the fourth cylinder is actually sucked into the fourth cylinder during the intake stroke β of the fourth cylinder. It is desirable to control the injection amount in accordance with the intake air amount.

However, as apparent from FIG. 35, since the fuel injection timing α of the fourth cylinder arrives before the intake stroke β of the fourth cylinder, the intake stroke β of the fourth cylinder at the fuel injection timing α of the fourth cylinder. It is impossible to realize fuel control based on the above.
Therefore, in the conventional apparatus, the fuel injection amount at the fuel injection timing α of the fourth cylinder is controlled based on the intake air amount estimated by the intake stroke γ of the first cylinder.

  In this case, particularly during transient operation, when the flow path area of the throttle changes rapidly, for example, as shown by the intake air amount (solid line) in FIG. 36, the actual intake air amount (broken line) and the fuel amount are calculated. It can be seen that the deviation from the amount of intake air to be used increases, which adversely affects exhaust gas, fuel consumption, drivability, and the like.

Further, in the fuel injection control by the above-mentioned conventional device, when the throttle downstream pressure, the in-cylinder pressure, the intake air amount into the cylinder and the exhaust air amount are estimated, the passage at three locations (throttle valve, intake valve and exhaust valve) is performed. Since the flow rate is estimated, the calculation load executed in the control unit increases.
In particular, the greater the number of revolutions of the internal combustion engine (hereinafter referred to as “engine speed”), the shorter the allowable calculation time for estimating the passage flow rate of each part. Calculations are not in time.
Further, if a more sophisticated control unit is installed in order to cope with a decrease in allowable time due to an increase in calculation load, a cost increase will be caused.

Therefore, in order to solve this problem, in addition to the fuel injection control of Patent Document 1 (estimation of the throttle downstream pressure and in-cylinder pressure and the intake air amount in real time according to the crank angle), for example, the first It is conceivable to use intake air amount estimation means.
The first intake air amount estimating means takes the intake air into the cylinder at the time when the intake valve closing of the control target cylinder is completed prior to the crank angle (actual control reference position) by the injection start timing of the control target cylinder. It is configured to predict and estimate the quantity. As a result, fuel injection control with higher accuracy than that of the above-described conventional device is realized based on the estimated intake air amount to the control target cylinder.

  However, in the first intake air amount estimation means, when the intake air amount into the cylinder at the time when the intake valve closing of the control target cylinder is completed is predicted and estimated prior to the crank angle based on the fluid dynamic equation, the intake air amount is estimated. It does not take into account the actual change in the throttle flow path area from the intake air amount estimation start timing at which the air amount prediction estimation is started until the intake valve closing completion time.

  Therefore, even if the first intake air amount estimation means is used in a transient state where the actual throttle flow passage area changes greatly between the intake air amount estimation start timing and the intake valve closing completion time. As shown in FIG. 36, a deviation occurs between the actual intake air amount (broken line) and the intake air amount (one-dot chain line) used for calculating the fuel amount, which eventually adversely affects exhaust gas, fuel consumption, drivability, and the like. Will be given.

JP-A-5-222998

  In the conventional internal combustion engine control device, in the case of the conventional device described in Patent Document 1, in accordance with the crank angle, the throttle downstream pressure and the cylinder pressure in real time, the intake air amount and the exhaust air amount into the cylinder, Therefore, as the intake air amount used for fuel injection control, for example, it is necessary to use the intake air amount of other cylinders that have completed the intake stroke before two strokes when the cylinder to be controlled completes the intake stroke. There was a problem that the difference between the actual intake air amount and the intake air amount used for calculating the fuel amount during transient operation becomes large, which adversely affects exhaust gas, fuel consumption, drivability, and the like.

In the case of the conventional device described in Patent Document 1, three points (throttle valve, intake valve, exhaust valve) are used for estimating the throttle downstream pressure, the cylinder pressure, the intake air amount into the cylinder, and the exhaust air amount. Since the passage flow rate is estimated, there is a problem that the calculation load executed in the control unit is large.
In addition, when the engine speed increases, the allowable calculation time of the estimated flow rate of each part decreases and the estimation calculation is not in time, so to avoid this, it becomes necessary to install a more sophisticated control unit, There was a problem of increasing the cost.

  Further, in addition to the fuel injection control of Patent Document 1, the first intake air amount estimation means is used, and the cylinder at the time when the intake valve closing completion of the control target cylinder is completed ahead of the crank angle by the injection start timing of the control target cylinder. Even if the estimated intake air amount is estimated and fuel injection control based on the estimated intake air amount to the target cylinder is applied, the intake air amount estimation start time to the intake valve closing completion time Therefore, in transient operation, there is still a difference between the actual intake air amount and the intake air amount used to calculate the fuel amount. There was a problem of adversely affecting fuel consumption and drivability.

  The present invention has been made to solve the above problems, and predicts the intake air amount into the cylinder at the time of completion of intake valve closing prior to the crank angle by the injection start timing of the cylinder to be controlled. The flow area of the intake air amount control means between the intake air amount estimation start timing and the intake valve closing completion time is estimated and estimated in consideration of the change of the flow area in the transient operation state. Thus, an object of the present invention is to obtain an internal combustion engine control device that can estimate the intake air amount with higher accuracy.

  An internal combustion engine control apparatus according to the present invention includes an intake air amount control means for controlling an intake air amount to an internal combustion engine by controlling a flow passage area, and a flow passage area calculation for calculating a flow passage area of the intake air amount control means. Means, a downstream pressure detecting means for detecting the pressure downstream of the intake air amount control means, a rotation speed detecting means for detecting the engine speed, and an intake air for estimating the intake air amount sucked into the cylinder of the internal combustion engine An air amount estimation means, the flow path area calculation means from the flow path area detection means for detecting the flow path area, and the intake air amount estimation start timing when the intake air amount estimation means starts the intake air amount estimation processing And an intake air amount estimating means for predicting and estimating the flow area until the intake valve closing completion time of the intake valve of the cylinder to be controlled of the internal combustion engine is completed. Upstream and below the air volume control means Fuel to the cylinder to be controlled from the intake air amount estimation start time using each pressure on the side, the flow path area, the engine speed, the intake air temperature of the internal combustion engine, and the cylinder volume of the internal combustion engine The intake air amount until the intake valve closing completion time is predicted and estimated before the injection start timing at which the injection is started.

  According to the present invention, by predicting and estimating the throttle opening, the actual intake air amount and the intake air amount used for the fuel amount control can be obtained even during transient operation in which the throttle opening changes rapidly (increase or decrease). It is possible to avoid a shift between the two.

Embodiment 1 FIG.
Hereinafter, the first embodiment of the present invention will be described in detail with reference to the drawings.
First, calculation processing by the first intake air amount estimation means will be described.
The first intake air amount estimation means is a real-time downstream pressure estimation control of the above-mentioned Patent Document 1 (based on a fluid dynamic equation, a throttle downstream pressure and a cylinder pressure in real time at every predetermined period according to a crank angle, and intake air. Control to estimate the intake air amount) and predictive estimation of the intake air amount into the cylinder at the completion of intake valve closing by the start of injection prior to the crank angle Control).

  In the real-time downstream pressure estimation control and the intake air amount prediction estimation control by the first intake air amount estimation means, the throttle downstream pressure P (CA) at an arbitrary crank angle CA is expressed by, for example, the following equation (1): It is estimated with a recurrence formula.

  However, in the equation (1), each variable indicates the following.

Note that g (CA, ΔCA) indicates a function (such as an estimation function of the throttle passage flow rate) used for estimating the throttle downstream pressure at the crank angle CA in addition to the predetermined period ΔCA.
In addition, the right side of Equation (1) is as follows:

Is a function for estimating. That is, the throttle downstream pressure P (CA−ΔCA) at an arbitrary crank angle CA−ΔCA is a basis for estimating the throttle downstream pressure P (CA) at the crank angle CA.
The crank angle CA is a crank angle based on the top dead center TDC during the intake stroke. In the case of a four-cylinder four-cycle engine, the crank angle CA is one cycle from 0 [°] to 720 [°].

  The intake air amount prediction estimation control immediately estimates the intake air amount into the cylinder at the time when the intake valve closing is completed from a predetermined time (hereinafter referred to as “predetermined time A”) before the injection start time. The purpose is to obtain an equation (1) based on a hydrodynamic equation from the upstream and downstream pressures of the throttle, the flow passage area of the throttle, the cylinder volume of the internal combustion engine, the engine speed and the intake air temperature. By repeating the recurrence formula until the intake valve closing completion time is reached prior to the crank angle, the throttle downstream pressure P (CA) and the cylinder pressure at the time of intake valve closing completion and the intake air amount are estimated. Complete the process.

Hereinafter, for convenience, the throttle downstream pressure and the in-cylinder pressure of the internal combustion engine in the intake air amount prediction estimation control are referred to as “predicted estimated downstream pressure” and “predicted estimated in-cylinder pressure”, respectively.
Further, the predicted estimated downstream pressure and the predicted estimated in-cylinder pressure at the time of completion of intake valve closing are referred to as “fuel control downstream pressure” and “fuel control in-cylinder pressure”, respectively.
Further, the intake air amount estimated from the in-cylinder pressure for fuel control and the in-cylinder volume and intake air temperature of the internal combustion engine at the time when the intake valve is closed is referred to as “fuel control intake air amount”.
Further, the throttle downstream pressure and the in-cylinder pressure in the real-time downstream pressure estimation control are referred to as “estimated downstream pressure” and “estimated in-cylinder pressure”, respectively.

In the first embodiment of the present invention, in the intake air amount prediction estimation control, in order to consider the change in the throttle flow path area from the predetermined time A to the completion time of intake valve closing, The throttle flow path area until the intake valve closing completion time is predicted and estimated. Since the throttle flow path area depends on the throttle opening, the throttle opening is predicted and estimated.
Thus, by predicting and estimating the throttle opening, even during transient operation where the throttle opening changes rapidly (increase or decrease), the actual intake air amount and the intake air amount used for fuel amount control There will be no deviation.

FIG. 1 is an explanatory diagram showing an estimation characteristic of a channel area (throttle opening) predicted and estimated according to Embodiment 1 of the present invention, where the horizontal axis indicates time and the vertical axis indicates throttle opening.
In FIG. 1, the dotted characteristic curve indicates the actual throttle opening, the one-dot chain line indicates the throttle opening used in the estimation control by the first intake air amount estimation means, and the solid line indicates the first embodiment of the present invention. The throttle opening used in intake air amount prediction estimation control is shown.

  Further, an arrow section from a broken line to a chain double-dashed line in FIG. 1 is a section that is a target for estimation of throttle opening in the intake air amount prediction estimation control according to the first embodiment of the present invention. The start time (broken line) of the air amount prediction estimation control) is set to a predetermined time A, and the end time (two-dot chain line) of each section corresponds to the intake valve closing completion time.

  FIG. 1 shows characteristics during transient operation (an operation state in which the change in throttle opening is large from the predetermined timing A to the completion of intake valve closing). FIG. 1 shows the characteristics according to the first embodiment of the present invention. As is clear from the relationship between the throttle opening (solid line) used during intake air amount prediction estimation control and the actual throttle opening (dotted line), throttle opening used during intake air amount prediction estimation control Changes substantially following changes in the actual throttle opening.

That is, in FIG. 1, in the intake air amount prediction estimation control using only the first intake air amount estimation means, the throttle opening (see the one-dot chain line) detected at the predetermined time A is used, so the actual throttle opening ( The difference from the dotted line reference) becomes large.
In contrast, in the intake air amount prediction estimation control according to the first embodiment of the present invention, the throttle opening between the predetermined timing A (see the broken line) and the intake valve closing completion time (see the two-dot chain line) is predicted. By estimating, the difference between the throttle opening (solid line) used in the intake air amount prediction estimation control and the actual throttle opening (dotted line) can be reduced.

Hereinafter, for convenience, the control for predicting and estimating the throttle opening used in the intake air amount predictive estimation control is referred to as throttle opening prediction estimation control, and the throttle opening obtained by the throttle opening prediction estimation control is estimated and estimated throttle opening. Called degrees.
FIG. 2 is an explanatory diagram showing the process of setting the predicted estimated downstream pressure according to the first embodiment of the present invention. The horizontal axis shows the crank angle, and the vertical axis shows the throttle downstream pressure and the estimated downstream pressure in each cycle. .

In FIG. 2, the predicted estimated downstream pressure is shown in relation to the actual throttle downstream pressure, the estimated downstream pressure at N cycles and N + 1 cycles.
That is, here, a multiple throttle system is assumed, the upper stage in FIG. 2 shows the relationship between the crank angle and the actual throttle downstream pressure, and the middle stage in FIG. 2 shows the crank angle and the estimated downstream pressure in the N cycle. FIG. 2 shows the relationship between the crank angle and the estimated downstream pressure in the N + 1 cycle.

According to Embodiment 1 of the present invention, as shown in FIG. 2, the estimated downstream pressure is estimated for each predetermined cycle by the real-time downstream pressure estimation control, while during the period from the predetermined timing A to the injection start timing, The downstream pressure for fuel control is estimated by intake air amount prediction estimation control.
At this time, in order to start the intake air amount prediction estimation control, it is necessary to obtain the throttle downstream pressure at the predetermined time A. The throttle downstream pressure at the predetermined time A is calculated as shown in FIG. It can be obtained by estimation processing based on estimation control.
Alternatively, a pressure sensor is provided on the downstream side of the throttle for each cylinder, and when the crank angle reaches the predetermined timing A of the cylinder to be controlled, the detected value of the throttle downstream pressure acquired by the pressure sensor is set to the throttle downstream at the predetermined timing A. It can also be used as pressure.

  Further, in Patent Document 1, the passage flow rate at three locations (throttle valve, intake valve, exhaust valve) is estimated in real time to estimate the throttle downstream pressure, cylinder pressure, intake air amount, etc. On the other hand, the first intake air amount estimation means suppresses the calculation load by estimating only the flow rate through the throttle portion and estimating the throttle downstream pressure, the cylinder pressure, the intake air amount, and the like.

Specifically, when the first intake air amount estimation means is applied to the multiple throttle system, an “intake valve closed model” that models the intake passage from the upstream side of the throttle to the intake valve, and a volume from the upstream side of the throttle. Two intake air amount estimation models are used, which are an “intake valve opening model” that models the intake passage to the cylinder in consideration of changes.
The intake valve closed model is used to estimate the throttle downstream pressure and in-cylinder pressure when the intake valve is closed, the intake air amount, and the like, and the intake valve open model is used when the intake valve is open. It is used to estimate the throttle downstream pressure and cylinder pressure, the intake air amount, and the like.

  In a general collective throttle system in which a throttle is installed in the intake passage where the intake pipes of the cylinders gather to control the intake air amount of the internal combustion engine, from the upstream side of the throttle to the inside of each cylinder taking into account the volume change A "collector throttle system model" (described later) that models the intake passage of the engine is used.

  Further, the atmospheric pressure and the intake air temperature used in the estimation process of the fuel control downstream pressure, the fuel control cylinder pressure and the fuel control intake air amount are acquired from the atmospheric pressure sensor and the temperature sensor, and the detected values of the respective sensors are obtained. By using this, it is possible to estimate the fuel control downstream pressure, the fuel control in-cylinder pressure, and the fuel control intake air amount with higher accuracy.

Hereinafter, Embodiment 1 of the present invention will be described taking as an example a case where it is applied to a multiple throttle system in which a throttle is installed for each cylinder.
In Embodiment 1 of the present invention, the estimation of the estimated downstream pressure at the predetermined time A by the real-time downstream pressure estimation control and the throttle opening between the predetermined time A and the completion time of the intake valve closing by the throttle opening prediction estimation control are performed. Then, based on the estimated downstream pressure at the predetermined time A, the estimated estimation of the intake air amount for fuel control by the intake air amount prediction estimation control is performed.

  In the first embodiment of the present invention, in the process of estimating the estimated downstream pressure and the intake air amount for fuel control, an “intake valve closed model” that models the intake passage from the throttle upstream side to the intake valve, and the throttle upstream An “intake valve opening model” is used in which the intake passage from the side to the cylinder in consideration of the volume change is modeled.

The intake valve closed model and intake valve open model are based on fluid dynamics equations based on throttle upstream pressure and throttle downstream pressure, cylinder pressure, throttle flow path area, cylinder volume, engine speed, and intake air temperature. The throttle passage flow rate is estimated, and new throttle downstream pressure and in-cylinder pressure are estimated and calculated from the estimated throttle passage flow rate and changes in the cylinder volume.
In other words, the calculation load is suppressed by calculating the passage flow rate of only the throttle portion, instead of calculating the passage flow rate of three places (throttle portion, intake valve portion, exhaust valve portion) as in the conventional device. .

Hereinafter, the first embodiment of the present invention will be described in more detail with reference to FIG.
FIG. 3 is a block diagram schematically showing the entire system of the internal combustion engine control apparatus according to Embodiment 1 of the present invention, and shows a multiple throttle system corresponding to four cylinders.
In FIG. 3, only one cylinder (first cylinder) 10 is representatively shown, but the second to fourth cylinders of the internal combustion engine (engine) are similarly configured.

  3, the internal combustion engine includes a throttle valve 1 that limits the intake air amount for each cylinder 10, a fuel injection valve 2 that controls the fuel injection amount and fuel injection timing, and the intake air amount and intake timing to the internal combustion engine. Is provided with an intake valve 3 for controlling the exhaust gas, an exhaust valve 4 for controlling the amount of exhaust air and the exhaust timing from the internal combustion engine, and an ignition plug 11 for generating a spark for burning the air-fuel mixture in the cylinder 10. .

The crankshaft 12 constituting the main body of the internal combustion engine is provided with a crank angle sensor 5 for generating a crank angle detection signal (indicating the control reference position of the internal combustion engine and the engine speed).
Furthermore, an air cleaner 13 for purifying intake air to the internal combustion engine is provided on the most upstream side of the intake passage.

The throttle valve 1 installed for each cylinder 10 is driven by a throttle actuator 6 installed for each throttle valve 1.
An intake passage 9 on the downstream side of the throttle 1 communicates with the cylinder 10 via the intake valve 3.

A throttle control unit 7 comprising a microcomputer electronically controls the opening of the throttle valve 1 by outputting a throttle opening control signal to the throttle actuator 6.
Similarly, the engine control unit 8 composed of a microcomputer electronically controls the fuel injection amount and fuel injection timing by the fuel injection valve 2 by outputting a fuel injection control signal to the fuel injection valve 2, and By outputting an ignition control signal to the spark plug 11, the ignition timing by the spark plug 11 is electronically controlled.

The throttle control unit 7 inputs a fuel control intake air amount signal to the engine control unit 8.
The engine control unit 8 also sends a target intake air amount signal, a crank angle signal (indicating the crank angle CA) corresponding to the control reference position for each cylinder, and an engine speed signal (engine speed) to the throttle control unit 7. Is input).

The throttle actuator 6 has a throttle opening sensor (hereinafter referred to as “TPS”) that detects the throttle opening, and sends a throttle opening detection signal (indicating the throttle opening TH) by the TPS to the throttle control unit 7. input.
Note that a plurality of throttle control units 7 are provided corresponding to each throttle actuator 6, and each throttle valve 1 is individually controlled by each throttle control unit 7.

  Based on the throttle opening detection signal input from the throttle actuator 6 and the engine speed signal, crank angle signal, and target intake air amount signal input from the engine control unit 8, the throttle control unit 7 And a fuel control intake air amount signal for the engine control unit 8 are generated.

The throttle control unit 7 determines a target throttle opening from a throttle opening detection signal, a fuel control intake air amount signal, and a target intake air amount signal, and from the engine speed signal and the crank angle signal, for fuel control. An estimation process such as the intake air amount is executed.
In FIG. 3, the throttle downstream pressure is the pressure in the intake passage 9 on the downstream side of the throttle 1, and the in-cylinder pressure is the pressure in the cylinder 10 of the internal combustion engine.

  The engine control unit 8 is an accelerator depression amount detection signal input from an accelerator position sensor (not shown), a crank angle detection signal input from the crank angle sensor 5, and a fuel control input from the throttle control unit 7. Based on the intake air amount signal, a fuel injection control signal for the fuel injection valve 2 of each cylinder is output.

The engine control unit 8 detects the engine speed Ne and the crank angle CA from the crank angle detection signal, determines the target intake air amount from the accelerator depression amount, the fuel control intake air amount, and the like, and determines the fuel control intake air amount and The fuel injection amount is determined from the target air-fuel ratio based on the operating state.
In addition, the fuel injection valve 2 shall be installed corresponding to each cylinder, and shall inject fuel independently for every cylinder.

By the way, as described above, when only the first intake air amount estimation means is used, the intake air amount into the cylinder at the time when the intake valve closing of the control target cylinder is completed is calculated based on the fluid dynamics equation as the crank angle. When predicting and estimating for the first time, changes in the actual throttle flow path area from the start of intake air amount estimation into the cylinder to the completion of intake valve closing are not taken into consideration.
On the other hand, in the first embodiment of the present invention, the actual throttle flow between the intake air amount estimation start time and the intake valve closing completion time is further added by adding the predictive estimation control of the throttle opening. In consideration of the change in the road area, the intake air amount is estimated with higher accuracy.

  That is, the throttle control unit 7 uses the throttle upstream pressure, the throttle downstream pressure, the flow path area, the engine speed Ne, the in-cylinder volume, and the intake air temperature, before the fuel injection start timing, Intake air amount prediction estimation means for predicting and estimating the intake air amount at the time of completion of closing, flow path area detection means for detecting the throttle flow area, and from the intake air amount estimation start time to the completion time of intake valve closing And a passage area predicting / estimating means for predicting and estimating the throttle passage area.

  Further, the first intake air amount estimating means in the throttle control unit 7 takes in the intake air when predicting and estimating the intake air amount into the cylinder when the intake valve closing of the control target cylinder is completed prior to the crank angle. The throttle flow path area between the amount estimation start time and the intake valve closing completion time is predicted and estimated.

Hereinafter, the throttle opening prediction estimation control according to the first embodiment of the present invention will be described in more detail with reference to the explanatory diagram of FIG.
FIG. 4 shows the predicted estimated throttle opening characteristic (time change) estimated by the throttle opening predictive estimation control. Note that the predicted estimated throttle opening is a throttle opening estimated and predicted between the predetermined timing A (time A) and the intake valve closing completion time (timing C).

  In FIG. 4, the horizontal axis represents time, and the vertical axis represents the throttle opening (actually detected throttle opening or predicted throttle opening), which was detected at time B (a unique time before the predetermined time A). Between the actual throttle opening THB, the actual throttle opening THA detected at time A, the slope DAB of the straight line connecting the throttle openings THB and THA, and from time A to time C (intake valve closing timing) The relationship between the estimated throttle opening THE and the target throttle opening THT is shown.

The throttle opening THE between the periods A and C is estimated by extending linear interpolation of the throttle opening between the periods B and A.
Further, after reaching the target throttle opening degree THT, the predicted estimated throttle opening degree THE is fixed to the target throttle opening degree THT as shown in FIG.

As shown in FIG. 4, the throttle control unit 7 detects the actual throttle opening THA detected at the predetermined timing A and the unique timing B before the predetermined timing A in the throttle opening prediction estimation control. The predicted estimated throttle opening THE from the predetermined time A to the time C is predicted and estimated by extending linear interpolation with the actual throttle opening THB.
The time B is set, for example, to a time before the predetermined control period (corresponding to a predetermined crank angle) from the predetermined time A.

In the throttle opening predictive estimation control, when the predicted estimated throttle opening THE reaches the target throttle opening THT by timing C (intake valve closing completion timing), the throttle control unit 7 sets the target throttle opening. The predicted estimated throttle opening THE after reaching THT is fixed at the target throttle opening until time C is reached.
The predicted estimated throttle opening THE is obtained by the throttle opening predictive estimation control having the above procedure.

  Further, the throttle control unit 7 includes two intake air amount estimation models, determines the state of the intake valve 3 based on operation state information from various sensors, and according to the state of the intake valve 3, FIG. The intake valve closing model shown in FIG. 6 and the intake valve opening model shown in FIG. 6 are switched and used.

The intake valve closing model shown in FIG. 5 is a model that estimates only the flow rate through the throttle valve 1 to estimate the downstream pressure of the throttle, the in-cylinder pressure, the intake air amount, etc. in order to reduce the calculation load. In the multiple throttle system, the intake passage from the upstream side of the throttle valve 1 to the intake valve 3 is modeled.
The intake valve opening model shown in FIG. 6 is a model of the intake passage from the upstream side of the throttle valve 1 to the cylinder in consideration of the volume change.

Here, the intake valve closing model (see FIG. 5) and the intake valve opening model (see FIG. 6) used in Embodiment 1 of the present invention will be described.
In FIG. 5, the channel area _AT corresponds to the channel (projected) area of the opening of the throttle valve 1.
5 and 6, subscripts “1”, “2”, “3”, and “23” attached after pressure P, volume V, and temperature T are respectively “upstream of throttle valve 1”. “, Downstream of throttle valve 1 to intake valve 3”, “inside cylinder 10”, and “downstream side of throttle valve 1 to inside cylinder 10”.

The intake valve closed model of FIG. 5 is a closed state of the intake valve 3 from “the crank angle IVC when the intake valve 3 is closed” to “the crank angle IVO when the intake valve 3 starts to open”. It is a model corresponding to.
Hereinafter, the opening time of the intake valve 3 is referred to as “IVO”, and the closing time of the intake valve 3 is referred to as “IVC”.

On the other hand, in the intake valve opening model of FIG. 6, the intake valve 3 is in the open state from “the crank angle IVO when the intake valve 3 starts to open” to “the crank angle IVC when the intake valve 3 is closed”. It is a corresponding model.
In each model, it is assumed that the temperature T ₁ of the intake air is constant (the temperature T ₁ on the upstream side of the throttle is constant) regardless of the region.

  The intake valve closed model (FIG. 5) is used to estimate the throttle flow rate, the throttle downstream pressure, the intake air amount, and the like when the intake valve 3 is closed. It is formed by the throttle downstream side from the valve 1 to the intake valve 3, and the inside of the cylinder is not considered.

In the closed intake valve model of FIG. 5, the throttle upstream side is constituted by the throttle upstream pressure P ₁ and the intake air temperature T ₁ , and the throttle opening is constituted by the throttle flow path area _AT .
Intake air passing through the throttle opening is subjected to pressure from the throttle upstream pressure P ₁ and the throttle downstream pressure P _2.

Further, the throttle downstream is constituted by a throttle downstream pressure P _2, a throttle downstream volume V _2, and the suction air temperature T _1.
Note that the pressure P ₁ on the upstream side of the throttle is handled as substantially atmospheric pressure, and the intake air temperature T ₁ on the upstream side of the throttle is handled as being constant throughout.
The throttle passage flow rate in the closed intake valve model of FIG. 5 is estimated from the following equations (2) and (3) based on the hydrodynamic equation.

  However, in the equations (2) and (3), each variable indicates the following.

Expressions (2) and (3) indicate the throttle passage flow rate per unit time, which is an index indicating whether or not the speed of the intake air passing through the throttle valve 1 becomes a sonic velocity. ₁ and the pressure P ₂ on the downstream side of the throttle (= P ₂ / P ₁ ) ”.
That is, Expression (2) is applied when the condition that the velocity of the intake air passing through the throttle valve 1 is less than the sonic speed (P ₂ / P ₁ > 0.5283) is satisfied, and Expression (3) is This is applied when the following condition (P ₂ / P ₁ ≦ 0.5283) is satisfied.

Hereinafter, the throttle control unit 7, the formula (2), and the throttle flow rate through per unit time obtained in (3), and a predetermined period, the throttle downstream pressure P _2, a throttle downstream volume V _2, the intake air temperature T ₁ is used to estimate the throttle downstream pressure after a predetermined period using the gas equation of state.

The throttle downstream pressure estimated in this way is further used as a basis for estimating the throttle downstream pressure after a predetermined period.
The above process is executed at predetermined intervals, and when the intake valve 3 starts to open, the model is switched to the intake valve opening model of FIG.

  The intake valve opening model shown in FIG. 6 includes a throttle upstream side, a throttle opening in order to estimate a throttle passage flow rate, a throttle downstream pressure, an in-cylinder pressure, an intake air amount, and the like when the intake valve 3 is open. , A throttle downstream side from the throttle valve 1 to the intake valve 3, and a cylinder whose volume changes according to the crank angle.

In the intake valve opening model of FIG. 6, the throttle upstream side, the throttle opening, and the throttle downstream side have the same configuration as the intake valve closed model (see FIG. 5). Also in this case, the intake air temperature T ₁ of, like described above, are treated as constant across.
The in-cylinder is constituted by an in-cylinder pressure P ₃ , an in-cylinder volume V _3, and an intake air temperature T _1, and the in-cylinder volume V ₃ changes according to the crank angle.

Further, the in-cylinder pressure P ₃ is balanced with the throttle downstream pressure P ₂ except when the intake valve 3 starts to open, and the pressure P ₂₃ from the downstream side of the throttle valve 1 to the cylinder 10 is P _23. It is assumed that the relationship = P ₂ = P ₃ is satisfied.
When estimating the throttle passage flow rate when the intake valve 3 starts to open, first, it is necessary to estimate the pressure when the throttle downstream pressure and the cylinder pressure at the time when the intake valve 3 starts to open are balanced.

The reason for this is as follows.
That is, since the exhaust stroke is performed immediately before the intake valve 3 is opened, the inside of the cylinder is almost at atmospheric pressure. When the intake valve 3 is opened in this state, the inside of the cylinder at almost atmospheric pressure and the downstream side of the throttle that is at negative pressure. This is because the throttle downstream pressure and the in-cylinder pressure are in an equilibrium state.
The throttle downstream pressure and in-cylinder pressure after pressure equilibrium are estimated by the following equation (4) based on the gas state equation.

  However, in the equation (4), each variable indicates the following.

Incidentally, the cylinder pressure when the intake valve 3 starts to open, since almost the atmospheric pressure, equal to the upstream intake air pressure P _1, the following relationship holds.

Further, in the intake valve open model of FIG. 6, when the throttle flow rate is estimated, the difference from the intake valve closed model of FIG. 5 is that the throttle downstream pressure and the in-cylinder pressure change due to the change in the in-cylinder volume. So these changes need to be taken into account.
Therefore, when estimating the flow rate through the throttle, first, assuming that there is no flow rate from the throttle valve 1 during a predetermined period, the throttle downstream pressure and the in-cylinder pressure when the in-cylinder volume changes, Estimated by the following equation (5), and based on the estimated throttle downstream pressure and in-cylinder pressure, the throttle passage flow rate is estimated by the following equations (6) and (7).

  However, in Expressions (5) to (7), each variable indicates the following.

を推定したうえで、この圧力を、式（５）における筒内圧力変化時の推定圧力

として、単位時間当りのスロットル通過流量を推定する。
以下、単位時間当りのスロットル通過流量と、所定周期と、現時点（スロットル弁１からの流量がないものと仮定したとき）のスロットル下流圧力および筒内圧力

と、スロットル下流容積Ｖ_２と現時点の筒内容積

との和と、吸入空気温度Ｔ_１とに基づき、気体の状態方程式を用いて、現時点のスロットル下流圧力および筒内圧力を推定する。
推定したスロットル下流圧力および筒内圧力は、さらに、所定周期後のスロットル下流圧力および筒内圧力を推定する際の基礎として用いられる。 Expressions (6) and (7) are similar to the expressions (2) and (3) described above.
At the time when the intake valve 3 starts to open, the throttle downstream pressure and the in-cylinder pressure after the pressure equilibrium are expressed by the above-described equation (4).

, And this pressure is calculated as the estimated pressure when the in-cylinder pressure changes in equation (5).

As a result, the flow rate through the throttle per unit time is estimated.
Hereinafter, the throttle downstream flow rate per unit time, the predetermined cycle, the current throttle downstream pressure and the in-cylinder pressure (assuming there is no flow rate from the throttle valve 1)

Throttle downstream volume V ₂ and current cylinder volume

And the sum of the, based on the intake air temperature T _1, using the state equation of gas to estimate the throttle downstream pressure and the in-cylinder pressure at the present time.
The estimated throttle downstream pressure and in-cylinder pressure are further used as a basis for estimating the throttle downstream pressure and the in-cylinder pressure after a predetermined period.

The above processing is executed at predetermined intervals, and when the intake valve closing completion time is reached, the amount of intake air into the cylinder using the gas state equation based on the in-cylinder pressure, the in-cylinder volume, and the intake air temperature. Is then switched to the intake valve closed model of FIG.
Hereinafter, the estimation process is executed while alternately switching the models of FIGS. 5 and 6.

Next, a first intake air amount estimation flow executed by the throttle control unit 7 according to the first embodiment of the present invention will be described with reference to FIGS.
7 to 15 are flowcharts showing a first intake air amount estimation flow, and FIG. 16 is an explanatory diagram showing a valve timing map of the intake valve 3. As shown in FIG.
17 is an area term map, FIG. 18 is a velocity term map, FIG. 19 is an in-cylinder volume map, and FIG. 20 is a predetermined time A map.

In the valve timing map of FIG. 16, the open / close state of the intake valve 3 is set in accordance with the crank angles IVC and IVO.
In the area term map of FIG. 17, the area term (the flow path area of the throttle valve 1) increases or decreases according to the throttle opening.
In the speed term map of FIG. 18, the speed term (the flow velocity of the intake air passing through the throttle valve 1) is such that the ratio of the throttle downstream pressure P ₂ —old and the throttle upstream pressure P ₁ before the predetermined period ΔCA is 0.5283 or less. When the sound speed is exceeded, it becomes a constant value.
In the in-cylinder volume map of FIG. 19, the in-cylinder volume periodically increases and decreases according to the crank angle (intake stroke, compression stroke, etc.).
In the predetermined time A map of FIG. 20, the predetermined time A becomes earlier in stages (advanced side) with respect to the fuel injection start time as the engine speed Ne becomes higher.

In the first intake air amount estimation flow of FIGS. 7 to 15, the intake valve open model and the intake valve close model shown in FIGS. 5 and 6 are used.
Further, the throttle control unit 7 incorporates values of the throttle upstream pressure P ₁ (= constant) and the intake air temperature T ₁ (= constant), and the crank angle is used as a parameter for determining whether the intake valve 3 is open or closed. It is assumed that the valve timing map (see FIG. 16) of the intake valve 3 is incorporated.

The first intake air amount estimation flow shown in FIGS. 7 to 15 is executed when a trigger sent from the engine control unit 8 to the throttle control unit 7 is received every predetermined cycle ΔCA based on the crank angle.
Thus, the estimated estimated downstream pressure, the estimated estimated in-cylinder pressure and the intake air amount for fuel control are estimated based on the intake air amount predictive estimation control, and the estimated downstream pressure and estimated in-cylinder are estimated based on the real-time downstream pressure estimation control. While estimating the pressure, the estimated estimated throttle opening THE is estimated based on the throttle opening predictive estimation control.

  The first intake air amount estimation flow is a diagram for executing the real-time downstream pressure estimation control in FIG. 7 to FIG. 9 (particularly, steps s1, s2, s4 to s20) and the intake air amount prediction estimation control. 12 to 14 and the control logic of FIG. 15 for executing the throttle opening prediction estimation control.

Note that the control logic of FIG. 10 for executing the intake valve closing model calculation shows the specific processing of step s7 in FIG.
Similarly, the control logic of FIG. 11 for executing the intake valve opening model calculation shows the specific processing of step s9 in FIG.

  In the throttle opening prediction estimation control (FIG. 15), the predicted estimated throttle opening THE is calculated using the following equation (18) based on the above-described method described with reference to FIG.

  However, in Equation (18), each variable indicates the following.

  Here, the slope DAB of the straight line is calculated from the following equation (19).

  However, in the equation (19), each variable indicates the following.

Further, in the intake air amount prediction estimation control and the real-time downstream pressure estimation control, the estimated estimated downstream pressure, the intake air amount for fuel control, and the like are calculated using the above equations (2) to (7) and the gas state equation. calculate.
In the first intake air amount estimation flow, based on the throttle passage flow rate per unit time and the gas state equation shown in the above formulas (2), (3), (6), and (7), a predetermined cycle The throttle downstream pressure that changes depending on the throttle passage flow rate from before ΔCA to the present time is calculated by the following equation (8).

  However, in Equation (8), each variable indicates the following.

Here, the area term indicates the throttle flow path area and is calculated from an area term map (FIG. 17) using the throttle opening TH as a parameter. The map value is calculated by actually measuring the flow rate through the throttle, and calculating (or determining from the projected area of the throttle opening) based on the measured value.
In the equation (8), each variable indicates the following.

は、クランク角をパラメータとした筒内容積マップ（図１９）から算出する）
さらに、式（８）において、変数は、以下のとおりである。 Here, the in-cylinder volume changes as the piston in the cylinder 10 moves up and down according to the crank angle.

Is calculated from the in-cylinder volume map (FIG. 19) with the crank angle as a parameter)
Furthermore, in Equation (8), the variables are as follows.

Also, as explained in the above equation (4), when estimating the throttle passage flow rate at the time when the intake valve 3 starts to open, first, the throttle downstream pressure and the cylinder pressure at the time when the intake valve 3 starts to open are calculated. It is necessary to estimate the pressure at equilibrium.
Therefore, in the first intake air amount estimation flow, the pressure at the equilibrium is calculated by the following equation (9) based on the equation (4).

  However, in Equation (9), each variable indicates the following.

Further, as shown in the equation (5), when calculating the throttle downstream pressure and the cylinder pressure in the intake valve opening model of FIG. 6, it is assumed that there is no flow rate from the throttle valve 1 during the predetermined period ΔCA. In addition, it is necessary to calculate the throttle downstream pressure and the cylinder pressure after the cylinder volume changes.
Therefore, in the first intake air amount estimation flow, the throttle downstream pressure and the in-cylinder pressure after the in-cylinder volume is changed are calculated by the following equation (10).

  However, in the equation (10), each variable indicates the following.

The above formulas (8) to (10) are expressed by the intake valve closing model (only the formula (8)) in FIG. 5 and the intake valve opening model (the formulas (8) and (10)) in FIG. At the beginning of opening, the throttle downstream pressure and the in-cylinder pressure when the intake valve 3 is open are estimated (or predicted estimated) by properly using the equation (9).
It should be noted that the estimated intake air amount sucked into the cylinder at the time of completion of intake valve closing is estimated from the estimated fuel control cylinder pressure, cylinder volume and intake air temperature using the gas equation of state. Can do.

Hereinafter, each step in the flow will be described.
In the first intake air amount estimation flow, each value is substituted into the current crank angle CA1 and calculation cycle ΔCA1 in the equations (8) to (10).
In FIG. 7, first, the intake air amount estimation means in the throttle control unit 7 determines whether or not the internal combustion engine (engine) is operating (step s1).

If it is determined in step s1 that the internal combustion engine is stopped (that is, NO), the intake flow rate is accumulated in the downstream volume of the throttle valve 1 via the throttle valve 1, and the throttle downstream pressure P ₂ There recovered to the atmospheric pressure, are considered to be the upstream intake air pressure P ₂ is approximately atmospheric pressure.

Therefore, in order to set the throttle upstream pressure P ₁ as the throttle downstream pressure P ₂ _old before the predetermined period ΔCA, the calculation process of “P ₂ _old = P ₁ ” is executed (step s3), and the node “4” is passed through. Then, the process proceeds to the process of FIG. 9 to end the first intake air amount estimation flow (FIGS. 7 to 9) and wait until the next trigger is received.

  On the other hand, if it is determined in step s1 that the engine is operating (that is, YES), the crank angle CA and the engine speed Ne are read from the engine control unit 8, and the throttle opening TH is read from the throttle actuator 6 (step s2). ) To determine the operating state of the internal combustion engine.

Subsequently, it is determined whether or not the intake valve 3 is closed at the current crank angle CA with reference to the valve timing map (FIG. 16) of the intake valve 3 (step s4).
If it is determined in step s4 that the intake valve 3 is open (that is, NO), the process proceeds to the process of FIG. 8 (step s12) via the node “2”.
On the other hand, if it is determined in step s4 that the intake valve 3 is closed (that is, YES), the crank angle (= CA−ΔCA) of the previous cycle (before the predetermined period ΔCA) is subsequently continued as in step s4. It is then determined whether or not the intake valve 3 is closed (step s5).

  If it is determined in step s5 that the intake valve 3 is closed (ie, YES), the process of “ΔCA1 = ΔCA” is executed to set the predetermined period ΔCA as the calculation period ΔCA1, and at the present time In order to set the current crank angle CA as the current crank angle CA1, a process of “CA1 = CA” is executed (step s6).

Subsequently, the estimated downstream pressure is calculated by real-time downstream pressure estimation control using the calculation of the intake valve closing model (FIG. 5) (step s7), and the process of FIG. 9 (step s21) is performed via the node “1”. move on.
A specific processing procedure of the intake valve closing model calculation (step s7) will be described later with reference to FIG.

  On the other hand, if it is determined in step s5 that the intake valve 3 has been opened in the previous cycle (ie, NO), in order to calculate the estimated downstream pressure and the estimated in-cylinder pressure at the crank angle IVC at the time of completion of closing. In order to execute the setting process “ΔCA1 = IVC− (CA−ΔCA)” of the calculation cycle ΔCA1, and to set the crank angle IVC at the closing completion time as the current crank angle CA1, “CA1 = IVC”. Is executed (step s8).

Subsequently, the estimated downstream pressure and the estimated in-cylinder pressure at the crank angle IVC at the time when the intake valve closing is completed are calculated by the real-time downstream pressure estimation control using the calculation of the intake valve opening model (FIG. 6) (step s9). .
A specific processing procedure of the intake valve opening model calculation (step s9) will be described later with reference to FIG.

Next, based on the engine speed Ne and the predetermined time A map (FIG. 20), the predetermined time A is calculated (step s10), and subsequently, the setting process “ΔCA1 = CA−IVC” for the calculation period ΔCA1 is executed. At the same time, the current crank angle CA1 setting process “CA1 = CA” is executed (step s11), and the process proceeds to step s7.
By the processing up to step s7 through steps s10 and s11, the estimated downstream pressure after the intake valve closing completion time (crank angle IVC) by the real-time downstream pressure estimation control is calculated.
Details of the calculation process (step s10) of the predetermined time A will be described later.

を算出し（ステップｓ２７）、また、体積項として、以下のように、スロットル下流容積Ｖ_２を設定する（ステップｓ２８）。 The intake valve closing model calculation (step s7) in FIG. 7 includes the processing (steps s27 to s32) shown in FIG.
In FIG. 10, first, based on the engine speed Ne and the calculation cycle ΔCA1, the time term

Calculates (step s27), also as a volume term, as follows, setting the throttle downstream volume _{V 2} (step s28).

と速度項マップ（図１８）とに基づき、速度項

を算出し（ステップｓ２９）、また、スロットル開度ＴＨと面積項マップ（図１７）から面積項

を算出する（ステップｓ３０）。 Subsequently, the ratio between the throttle downstream pressure P ₂ _old and the throttle upstream pressure P ₁ before the predetermined period ΔCA

And the speed term map (FIG. 18)

(Step s29), and the area term from the throttle opening TH and the area term map (FIG. 17).

Is calculated (step s30).

Next, the estimated downstream pressure at the current crank angle CA1 is calculated using the above equation (8) (step s31), and the throttle downstream pressure P ₂ _old before the predetermined period ΔCA is calculated as follows. The throttle downstream pressure is set (step s32).

  When the calculation process of the intake valve closing model (FIG. 10) is thus completed, the process exits step s7 in FIG. 1 and proceeds to step s21 in FIG. 9 via the node “1”.

を算出し（ステップｓ３３）、また、現時点のクランク角ＣＡ１と筒内容積マップ（図１９）に基づき、現時点のクランク角ＣＡ１での筒内容積

を算出して、体積項（容積項）

を算出する（ステップｓ３４）。 On the other hand, when the intake valve 3 is open at the crank angle (= CA−ΔCA) of the previous cycle and the intake valve 3 is closed at the current crank angle (= CA), that is, from step s5 in FIG. When the routine proceeds to step s8, intake valve closing model calculation (step s9) is executed.
The intake valve opening model calculation (step s9) is configured by the processing (steps s33 to s41) shown in FIG.
In FIG. 11, first, based on the engine speed Ne and the calculation cycle ΔCA1, the time term

(Step s33), and based on the current crank angle CA1 and the in-cylinder volume map (FIG. 19), the in-cylinder volume at the current crank angle CA1.

To calculate the volume term (volume term)

Is calculated (step s34).

Further, using equation (10), the estimated downstream pressure and the estimated in-cylinder pressure at CA1 (assuming that there is no flow rate from the throttle) in the intake valve opening model are calculated (step s35).
Subsequently, as the throttle downstream pressure P ₂ _old before the predetermined period ΔCA, the current throttle downstream pressure is set as follows (step s36).

と速度項マップ（図１８）とに基づいて、速度項

を算出し（ステップｓ３７）、さらに、スロットル開度ＴＨと面積項マップ（図１７）とに基づき、面積項

を算出する（ステップｓ３８）。
次に、前述の式（８）を用いて、現時点のクランク角ＣＡ１での推定下流圧および推定筒内圧力を算出し（ステップｓ３９）、所定周期ΔＣＡ前の筒内容積Ｖ_３＿ｏｌｄとして、以下のように、現時点の筒内容積を設定する（ステップｓ４０）。 Further, the ratio between the throttle downstream pressure P ₂ _old and the throttle upstream pressure P ₁ before the predetermined period ΔCA

And the speed term map (FIG. 18)

Is calculated (step s37), and the area term is further calculated based on the throttle opening TH and the area term map (FIG. 17).

Is calculated (step s38).
Next, the estimated downstream pressure and estimated in-cylinder pressure at the current crank angle CA1 are calculated using the above-described equation (8) (step s39), and the in-cylinder volume V ₃ _old before the predetermined period ΔCA is as follows: Thus, the current in-cylinder volume is set (step s40).

Further, as the throttle downstream pressure P ₂ _old before the predetermined period ΔCA, the current throttle downstream pressure is set as follows (step s41).

When the calculation process of the intake valve opening model (FIG. 11) is thus completed, the process exits step s9 in FIG. 1 and proceeds to the next step s10.
The calculation process of the predetermined time A in step s10 is executed based on the engine speed Ne and the predetermined time A map (a map using the engine speed Ne as a parameter) in FIG.

As shown in FIG. 20, at a predetermined time A, in order to secure the estimation processing time as the engine speed Ne increases, the advance side is increased by a predetermined period ΔCA in a direction in which the start of the intake air amount prediction estimation control is advanced. Shifted to.
After the predetermined timing A is calculated in this way, in step s11, “ΔCA1 = CA−IVC” and “CA1 = CA” are executed, and the estimated downstream pressure after the intake valve closing completion time (crank angle IVC) is reached. Prepare for the calculation process.
Further, in step s7, the intake valve closing model calculation is executed to calculate the estimated downstream pressure at the current crank angle CA1, and the process proceeds to step s21 in FIG.

Next, the processing in the case where it is determined in step s4 in FIG. 7 that the intake valve 3 is open (that is, NO) at the present time (= CA) will be described.
In this case, the process proceeds from step s4 to the process of FIG. 8 via the node “2”.
In FIG. 8, first, it is determined whether or not the intake valve 3 has already been opened at the crank angle (= CA−ΔCA) of the previous cycle (step s12).

  If it is determined in step s12 that the intake valve 3 has already been opened (that is, YES), “ΔCA1 = ΔCA” and “CA1 = CA” are executed similarly to step s6 described above, and then step s9. The estimated intake valve opening model calculation described in the above item is executed to calculate the estimated downstream pressure and the estimated in-cylinder pressure at CA1 (step s14), and the process proceeds to step s21 in FIG.

  On the other hand, if it is determined in step s12 that the intake valve 3 is closed (that is, NO) in the previous cycle (= CA−ΔCA), a process of calculating the estimated downstream pressure at the crank angle IVO at the valve opening start time. (Steps s15 and s16) and processing (steps s17 to s20 and s14) for calculating the estimated downstream pressure and the estimated in-cylinder pressure after the crank angle IVO are executed.

  First, in order to calculate the estimated downstream pressure at the crank angle IVO, the setting process “ΔCA1 = IVO− (CA−ΔCA)” of the calculation cycle ΔCA1 is executed, and the valve opening start time is set as the current crank angle CA1. In order to set the crank angle IVO, the process of “CA1 = IVO” is executed (step s15).

を算出する（ステップｓ１７）。
続いて、クランク角ＩＶＯでのスロットル下流圧力と筒内圧力とが平衡したときの圧力を、前述の式（９）を用いた推定演算により算出する（ステップｓ１８）。
以下、前述と同様に、所定周期ΔＣＡ前のスロットル下流圧力Ｐ_２＿ｏｌｄを、以下のように設定する（ステップｓ１９）。 Subsequently, the estimated downstream pressure at the crank angle IVO at the valve opening start time is calculated by the intake valve closing model calculation process similar to that described above (step s7) (step s16).
Further, based on the crank angle IVO and the in-cylinder volume map (FIG. 19), the in-cylinder volume at the crank angle IVO.

Is calculated (step s17).
Subsequently, the pressure when the throttle downstream pressure and the in-cylinder pressure at the crank angle IVO are balanced is calculated by the estimation calculation using the above-described equation (9) (step s18).
Thereafter, similarly to the above, the throttle downstream pressure P ₂ —old before the predetermined period ΔCA is set as follows (step s19).

  Further, the processing of “ΔCA1 = CA−IVO” and “CA1 = CA” is executed (step s20), and the process proceeds to the intake valve opening model calculation (step s14), and the estimated downstream pressure and estimated at the current crank angle CA1. After the in-cylinder pressure is calculated, the process proceeds to step s21 in FIG. 9 via the node “3”.

Next, the process (steps s21 to s23) in FIG. 9 will be described.
The processing after step s21 corresponds to intake air amount prediction estimation control and throttle opening prediction estimation control.
In FIG. 9, first, in order to determine whether or not the intake air amount prediction estimation control should be executed, it is determined whether or not the crank angle CA is at a predetermined time A (step s21).

If it is determined in step s21 that the crank angle CA is the predetermined time A (that is, YES), the calculation process of the intake air amount for fuel control by the intake air amount prediction estimation control and the throttle opening prediction estimation control is executed. (Step s23).
Step s23 includes the processes shown in FIGS. 12 to 14 (steps s42 to s65).

In FIG. 12, first, pre-preparation processing for intake air amount prediction estimation control and throttle opening prediction estimation control is executed (steps s42, s43, s64), and predicted estimated throttle opening THE by throttle opening prediction estimation control. Is calculated (steps s44, s45, s65).
Subsequently, in FIGS. 12 to 14, the estimated estimated downstream pressure and estimated estimated in-cylinder pressure (= downstream pressure for fuel control and fuel) at the intake valve closing completion time (crank angle IVC) by intake air amount predictive estimation control. In-cylinder pressure for control) is calculated (steps s46 to s61).
Further, in FIG. 14, the fuel control intake air amount is calculated from the fuel control in-cylinder pressure (step s62), and the processing routine of step s23 is terminated via step s63 similar to step s43. The process proceeds to step s22.

In step s42 of FIG. 12, processing of “CA ′ = CA” and “THE = TH” is executed.
Here, CA ′ is a crank angle used when the intake air amount prediction estimation control and the throttle opening prediction estimation control are executed.

Next, in step s43, the current throttle downstream pressure is set as follows as the throttle downstream pressure P ₂ _old before the predetermined period ΔCA.

Thereby, the estimated downstream pressure at the present time (= predetermined time A) is stored.
In step s64, the slope DAB of linear interpolation used in the throttle opening prediction estimation control is calculated by the following equation (20).

However, in Expression (20), TH_old represents the throttle opening (previous history value) before the predetermined period ΔCA.
Equation (20) is substantially the same as Equation (19) described above, and only some variables are modified. That is, the throttle openings THA and THB in the equation (19) respectively correspond to the throttle opening TH at the predetermined timing A and the previous throttle opening TH_old in the predetermined timing A in the equation (20).

The following steps s44 to s61 and s65 are loop control that is repeated until the crank angle CA ′ reaches the crank angle IVC at the completion of intake valve closing.
First, the crank angle CA ′ increasing process “CA ′ = CA ′ + ΔCA” is executed (step s45), the crank angle CA ′ is advanced by a predetermined period ΔCA, and then the process proceeds to step s65.

In step s65, a predicted estimated throttle opening THE is calculated by executing a predicted estimated throttle opening calculation process.
The calculation process (step s65) of the predicted estimated throttle opening THE is configured by the processes (steps s66 to s69) shown in FIG.

In FIG. 15, first, it is determined whether or not the predicted estimated throttle opening THE has already reached the target throttle opening THT (step s66).
If it is determined in step s66 that the predicted estimated throttle opening THE has reached the target throttle opening THT (that is, YES), the process routine of FIG. 15 is exited and the process proceeds to step s46 in FIG.

  On the other hand, if it is determined in step s66 that the predicted estimated throttle opening THE has not reached the target throttle opening THT (that is, NO), the predicted estimation at the crank angle CA ′ is performed using linear interpolation of the slope DAB. The throttle opening THE is calculated from the following equation (21) (step s67).

Equation (21) is substantially the same as Equation (18) described above, and only some variables are modified.
Thus, after calculating the predicted estimated throttle opening THE at the crank angle CA ′, it is then determined whether or not the predicted estimated throttle opening THE has reached the target throttle opening THT (step s68), and THE <THT If it is determined (that is, NO), the process routine of FIG. 15 is exited and the process proceeds to step s46 in FIG.

  On the other hand, if it is determined in step s68 that the predicted estimated throttle opening degree THE has reached the target throttle opening degree THT (that is, YES), a fixed setting process of the predicted estimated throttle opening degree THE is executed as follows. (Step s69), the process proceeds to step s46 in FIG.

の算出において、スロットル開度ＴＨではなく予測推定スロットル開度ＴＨＥを用いる点とを除けば、基本的に前述のステップｓ４〜ｓ２０と同じである。 By the way, steps s46 to s60 in FIGS. 12 and 13 are different from steps s4 to s20 in FIGS. 7 and 8 described above in that the crank angle is changed from CA to CA ′. , Area terms in intake valve closing model calculation (steps s49, s56) and intake valve opening model calculation (steps s51, s54)

Is basically the same as steps s4 to s20 described above except that the estimated estimated throttle opening THE is used instead of the throttle opening TH.

Therefore, detailed description of steps s46 to s60 corresponding to steps s4 to s20 is omitted.
Specifically, in both, each step has the following correspondence (a) to (c).

(A) In “steps s46 to s49”, the aforementioned “steps s4 to s7” (the previous cycle (= CA−ΔCA) is closed, and the intake valve 3 is closed at the present time (= CA). State).
(B) “Steps s46, s52 to s54” are the above-mentioned “Steps s4, s12 to s14” (the intake valve 3 is open at the previous cycle (= CA−ΔCA) and the current time (= CA). Corresponds to the state of open).
(C) “Step s54 via steps s46, s52, s55 to s60” is replaced with “step s14 via steps s4, s12, s15 to s20” described above (in the previous cycle (= CA−ΔCA), the intake valve 3 Is closed and the intake valve 3 is open at the present time (= CA).

  In addition, the above-described “step s7 via steps s4, s5, s8 to s11” (the intake valve 3 is open in the previous cycle (= CA−ΔCA), and the intake valve 3 is closed at the present time (= CA). 12 and FIG. 13, since it is not necessary to calculate the estimated downstream pressure after the intake valve closing completion time (crank angle IVC) in the intake air amount predictive estimation control, the “steps s4, s5 , “Steps s4, s5, s8, and s9” and “steps s46, s47, d50, and d51” are omitted. Corresponds.

の算出処理と、吸気弁開モデル計算（ステップｓ５１、ｓ５４）におけるステップｓ３８（図３８参照）の面積項

の算出処理とにおいては、スロットル開度ＴＨではなく、予測推定スロットル開度ＴＨＥが用いられる。 Furthermore, as described above, the area term of step s30 (see FIG. 10) in the intake valve closing model calculation (steps s49 and s56) in FIGS.

And the area term of step s38 (see FIG. 38) in the intake valve opening model calculation (steps s51 and s54).

In this calculation process, not the throttle opening TH but the estimated estimated throttle opening THE is used.

Hereinafter, after executing the loop control of steps s44 to s61 shown in FIGS. 12 to 14 to calculate the downstream pressure for fuel control and the in-cylinder pressure for fuel control at the crank angle IVC when the intake valve closing is completed, Proceed to step s62 in FIG.
In step s62, the throttle control unit 7 uses the gas state equation to calculate the fuel based on the in-cylinder pressure for fuel control, the in-cylinder volume at the crank angle IVC when the intake valve closing is completed, and the intake air temperature. The control intake air amount is calculated, and the calculated fuel control intake air amount is transmitted to the engine control unit 8.

Subsequently, as the throttle downstream pressure P ₂ _old before the predetermined period ΔCA, the throttle downstream pressure at the predetermined time A is set as follows (step s63).

This prepares for real-time downstream pressure estimation control to be executed after receiving the next trigger.
Thereafter, the process routine of FIG. 14 is exited, and the process proceeds to step s22 in FIG.
As described above, in FIG. 9, when it is determined as “NO” in step s21 (the crank angle CA is not the predetermined timing A), and step s23 (fuel control intake air amount calculation processing) is completed, and step s63 is completed. When the process is executed up to (FIG. 14), the process proceeds to step s22.
In step s22, the throttle opening TH at the present predetermined time A is set as follows as the throttle opening TH_old before the predetermined period ΔCA.

As a result, the current throttle opening TH is stored, the first intake air amount estimation flow is terminated, and the process waits until the next trigger is received.
By executing the above processing by the throttle control unit 7 provided for each cylinder during the operation of the internal combustion engine, even in the configuration without the air flow sensor or the pressure sensor (FIG. 3), from the predetermined timing A to the fuel injection start timing. In addition, it is possible to predict and estimate the fuel control intake air amount of the cylinder to be controlled prior to the crank angle.
At this time, in the prediction estimation process, as shown in FIG. 4, the throttle opening THE from the predetermined time A to the intake valve closing completion time is predicted and estimated.

  As described above, the internal combustion engine control apparatus according to Embodiment 1 of the present invention includes the intake air amount control means (throttle valve 1) for controlling the intake air amount to the internal combustion engine by controlling the flow passage area; A flow passage area calculating means (throttle control unit 7) for calculating a flow passage area of the intake air amount control means, a downstream pressure detecting means (throttle control unit 7) for detecting a pressure downstream of the intake air amount control means, Rotational speed detection means (crank angle sensor 5, engine control unit 8) for detecting the engine rotational speed Ne, and intake air quantity estimation means (throttle control unit 7) for estimating the intake air quantity sucked into the cylinder of the internal combustion engine And.

Further, the flow path area calculating means includes a flow path area detecting means (TPS) for detecting the flow path area (throttle opening TH), and an intake air amount estimating means for starting the intake air amount estimating process by the intake air amount estimating means. And a passage area predicting means for predicting and estimating the passage area from the start time to the intake valve closing completion point (crank angle IVC) at which the intake valve of the control target cylinder of the internal combustion engine is closed.
The intake air amount estimation means includes the upstream and downstream pressures of the intake air amount control means, the flow passage area, the engine speed Ne, the intake air temperature of the internal combustion engine, and the cylinder volume of the internal combustion engine. By using this, the intake air amount until the intake valve closing completion time is predicted and estimated between the intake air amount estimation start timing and the injection start timing at which fuel injection to the controlled cylinder is started.

Further, the channel area estimation means uses the intake air amount estimation start timing (predetermined timing A) and the channel area detected at a predetermined timing (timing B) before the intake air amount estimation start timing, The flow passage area of the intake air amount control means between the intake air amount estimation start timing and the intake valve closing completion time is predicted and estimated.
The flow path area predicted and estimated by the flow path area estimation means is fixedly set to a predetermined value over a period from when the predetermined value (target throttle opening degree THT) is reached to when the intake valve closing is completed.
The intake air amount control means controls the flow channel area to a target value and sets the target value of the flow channel area at the intake air amount estimation start timing to a predetermined value.

The intake air amount estimation means estimates the intake air amount sucked into the cylinder between the intake air amount estimation start timing and the intake valve closing completion time based on the in-cylinder pressure at the intake valve closing completion time. .
The intake air amount estimating means includes a predicted estimated downstream pressure setting means, and the predicted estimated downstream pressure setting means calculates the estimated estimated downstream pressure at the time when the intake valve closing completion is estimated prior to the crank angle of the internal combustion engine. The in-cylinder pressure when the intake valve closing is completed is set.

The predicted estimated downstream pressure setting means includes the previous estimated estimated downstream pressure, the pressure upstream of the intake air amount control means, the flow passage area of the intake air amount control means, the cylinder volume of the internal combustion engine, and the engine speed. By estimating the estimated estimated downstream pressure after a predetermined period from the previous time based on Ne and the intake air temperature of the internal combustion engine, and repeatedly executing the estimated estimated downstream pressure after the predetermined period ΔCA from the previous time, Estimate the estimated estimated downstream pressure when the intake valve is closed.
The downstream pressure estimation start timing for starting the estimation process of the predicted estimated downstream pressure is set to a predetermined timing before the injection start timing. The predetermined timing is greater than the injection start timing as the engine speed Ne increases. Thus, the downstream pressure estimation start timing is shifted in a direction that is advanced.

  Further, each intake valve 3 provided corresponding to each of the plurality of cylinders 10 of the internal combustion engine communicates with one end of a plurality of independent intake pipes, and communicates a collecting portion with the other end of each independent intake pipe. In the configuration in which the intake air amount restriction means is provided in the independent intake pipe, the intake air amount estimation means (throttle control unit 7) has two intake air amount estimation models, and the two intake air amount estimation models are An “intake valve closed model” in which an intake passage from the upstream side of the intake air amount control means to each intake valve 3 is modeled, and an intake passage from the upstream side of the intake air amount control means to the cylinder in consideration of the volume change It consists of an "intake valve open model" that models

The downstream pressure detection means includes the previously estimated downstream pressure of the intake air amount control means, the upstream pressure of the intake air amount control means, the flow passage area of the intake air amount control means, and the cylinder volume of the internal combustion engine. Then, based on the engine speed Ne and the intake air temperature of the internal combustion engine, the pressure on the downstream side of the current intake air amount control means is estimated.
Further, the downstream pressure detection means estimates the downstream pressure of the current intake air amount control means for each predetermined period ΔCA according to the crank angle CA of the internal combustion engine.

The intake air amount control means includes the throttle valve 1, and the flow path area calculation means including the flow path area detection means and the flow path area prediction means calculates the flow path area based on the opening degree of the throttle valve 1. .
Further, the rotational speed detection means includes a crank angle sensor 5 for detecting the crank angle CA of the internal combustion engine, detects the engine rotational speed Ne, and sets the in-cylinder volume set based on the crank angle CA (operation stroke). To detect.

  According to Embodiment 1 of the present invention, the above control causes a transient operation state in which the actual throttle opening greatly changes between the time when the intake air amount prediction estimation control is started and the time when the intake valve closing is completed. In this case, the difference between the throttle opening used in the intake air amount predictive estimation control and the actual throttle opening can be suppressed to be small, so that the accuracy of the estimated intake air amount for fuel control to the cylinder to be controlled is estimated. Thus, highly accurate fuel injection control can be realized.

  Further, instead of calculating the passage flow rate at three locations (throttle valve 1, intake valve 3, exhaust valve 4) as in the conventional device, only the passage flow rate of throttle valve 1 is calculated, and the throttle downstream pressure, cylinder Since the internal pressure and the intake air amount can be estimated, the calculation load can be reduced.

  Further, in the above description, as shown in FIG. 3, a description has been given of a system in which the throttle control unit 7 performs the intake air amount estimation process and the engine control unit 8 performs the fuel amount calculation process. However, the function of the throttle control unit 7 may be integrated into the engine control unit 8, and the intake air amount estimation may be performed by the engine control unit 8 for all processes.

Embodiment 2. FIG.
In the first embodiment (FIG. 3), the sensor for detecting the throttle downstream pressure is not particularly installed, and the throttle downstream pressure at the predetermined time A is estimated by the real-time downstream pressure estimation control in the throttle control unit 7. However, the throttle downstream pressure at the predetermined time A may be detected by the pressure sensor 14 as shown in FIG.

FIG. 21 is a block diagram schematically showing the entire system of the internal combustion engine control apparatus according to Embodiment 2 of the present invention. Components similar to those described above (see FIG. 3) are denoted by the same reference numerals as above. Or, “A” is added after the reference numerals, and the detailed description is omitted.
FIG. 21 shows the system configuration of the multiple throttle as described above, and only the first cylinder is representatively shown as the cylinder 10, but the second to fourth cylinders are similarly configured. ing.

21 differs from FIG. 3 only in that a pressure sensor 14 is provided in the intake passage 9 on the downstream side of each throttle valve 1.
In this case, the throttle control unit 7A executes the above-described throttle opening prediction estimation control and intake air amount prediction estimation control based on the throttle downstream pressure at the predetermined time A detected by the pressure sensor 14, thereby controlling the fuel. Estimate the intake air volume.

Similarly to the above, the intake valve closing model (FIG. 5) and the intake valve opening model (FIG. 6) are used in order to reduce the calculation load in the estimation downstream pressure and fuel control intake air amount estimation process compared to the conventional apparatus. Use.
Thus, instead of calculating the passage flow rate at three locations (throttle part, intake valve part, exhaust valve part) as in the conventional device, only the passage flow rate of the throttle part is calculated.

In FIG. 21, the pressure sensor 14 transmits a throttle downstream pressure detection signal to each throttle control unit 7A.
Note that the description of the intake valve closing model and the intake valve opening model having the same configurations and equations as in FIGS. 5 and 6 will be omitted.

Next, the second intake air amount estimation flow executed in the throttle control unit 7A in FIG. 21 will be described with reference to the flowchart in FIG.
In FIG. 22, steps s10 and s23 are the same processing as described above (see FIGS. 7 and 9).
Also, the second intake air amount estimation flow shown in FIG. 22 is similar to the above, because each throttle valve 1 is provided in an individually controlled multiple throttle system. This is performed using a model and an intake valve closing model.

Further, the second intake air amount estimation flow is such that when the crank angle CA reaches a predetermined period A calculated from a predetermined time A map (see FIG. 20), the engine control unit 8 applies to the throttle control unit 7A. This is executed when a trigger is sent.
Accordingly, the throttle opening prediction prediction control is used to predict and estimate the throttle opening from the predetermined timing A to the intake valve closing completion time, and then the intake air amount prediction estimation control is used to predict the predicted estimated downstream pressure and the predicted estimation cylinder. The internal pressure and the intake air amount for fuel control are estimated.

Further, in the same manner as described above, the throttle control unit 7A, the value of the throttle upstream pressure P1, the suction with the value of the air temperature T ₁ is inputted, the valve timing maps (Figure intake valve 3 in which the crank angle CA as a parameter 16) is incorporated.

The second intake air amount estimation flow is configured only by control logic that executes throttle opening prediction estimation control and intake air amount prediction estimation control.
That is, in the same way as the first intake air amount estimation flow described above, the above-described equations (8) to (10), (20), (21) The predicted estimated downstream pressure, the intake air amount for fuel control, and the like are calculated using the state equation and various maps (FIGS. 16 to 20).

の読込処理および代入処理を別処理ステップで実行するものとする。
次に、ステップｓ２３においては、前述と同一の処理（図１２内のステップｓ４２〜ｓ６５）により、燃料制御用吸入空気量を算出する。
続いて、ステップｓ１０においては、前述と同一の処理により、所定時期Ａを算出してエンジン制御ユニット８に送信する。 In FIG. 22, after receiving the trigger from the engine control unit 8, the throttle control unit 7A first reads the crank angle CA and the engine speed Ne from the engine control unit 8, and also reads the throttle opening TH from the throttle actuator 6. The throttle downstream pressure is read from the pressure sensor 14 (step s101).
In the throttle control unit 7A, the throttle opening detected before the predetermined period ΔCA of the predetermined time A before the start of the second intake air amount estimation flow.

The reading process and substitution process are executed in separate processing steps.
Next, in step s23, the intake air amount for fuel control is calculated by the same processing as described above (steps s42 to s65 in FIG. 12).
Subsequently, in step s10, the predetermined time A is calculated and transmitted to the engine control unit 8 by the same processing as described above.

Thereafter, the second intake air amount estimation flow in FIG. 22 is terminated, and the process waits until the next trigger is received.
By executing the above processing with the throttle control unit 7A provided for each cylinder during the operation of the internal combustion engine, the fuel control intake air amount estimation processing using the pressure sensor 14 can be completed.

According to the second intake air amount estimation flow (FIG. 22) according to the second embodiment of the present invention, since the pressure sensor 14 is provided for each cylinder, the cost is higher than that in the first embodiment. However, as can be seen from the first intake air amount estimation flow (FIGS. 7 to 9), the fuel control intake air amount estimation processing can be executed with simpler control logic.
Further, since the pressure downstream of the throttle at the predetermined time A is detected by the pressure sensor 14, it is possible to realize a more accurate estimation of the intake air amount for fuel control based on the actual detected pressure value.

Embodiment 3 FIG.
In the first and second embodiments, the example applied to the multiple throttle system has been described. However, as shown in FIG. 23, the present invention may be applied to a collective throttle system.
FIG. 23 is a block diagram schematically showing the entire system of the internal combustion engine control apparatus according to Embodiment 3 of the present invention. Components similar to those described above (see FIGS. 3 and 21) are denoted by the same reference numerals as those described above. It attaches | subjects or attaches | subjects "B" after a code | symbol, and abbreviate | omits detailed description.

In FIG. 23, the difference from the above is that the throttle valve 1 is provided in the collecting portion of the intake passage, the intake passage 9B on the downstream side of the throttle is located in the collecting portion, and the upstream side of the throttle valve 1 is greatly different. The atmospheric pressure sensor 15 and the temperature sensor 16 are provided.
In this case, by providing the atmospheric pressure sensor 15 and the temperature sensor 16, the atmospheric pressure correction process and the intake air temperature correction process that are not applied in the first and second embodiments are incorporated.

  In the third embodiment of the present invention, the estimated downstream pressure is estimated at the predetermined timing A by the real-time downstream pressure estimation control as described above, and from the predetermined timing A by the throttle opening prediction estimation control. After predicting and estimating the throttle opening until the intake valve closing completion time (crank angle IVC), the intake air amount for fuel control by the intake air amount predictive estimation control based on the estimated downstream pressure at the predetermined time A is determined. Perform the estimation process.

  In the above-described first and second embodiments, in order to reduce the calculation load required for the estimation downstream pressure and fuel control intake air amount estimation processing, only the throttle unit is used by using the intake valve closing model and the intake valve opening model. In the third embodiment of the present invention, only the throttle part is obtained by using the “collection part throttle system model” in which the intake passage from the upstream side of the throttle to the inside of each cylinder in consideration of the volume change is modeled. The calculation load is reduced by calculating the passage flow rate.

  In the third embodiment of the present invention, the reason why the intake valve closed model and the intake valve open model are not used is that in the collective throttle system, each cylinder is shielded by the throttle valve 1 on the throttle downstream side 9B. Since the intake valves 3 of at least one cylinder 10 are always open, and when the intake valves 3 of two or more cylinders 10 are open, all the intake valves 3 are open. This is because it is necessary to consider the cylinder volume of the cylinder 10.

  Further, in the third embodiment of the present invention, control for correcting the throttle upstream pressure and the intake air temperature used when executing the real-time downstream pressure estimation control and the intake air amount prediction estimation control with the sensor detection value is also executed.

The collective throttle system shown in FIG. 23 will be described by taking the case of a four-cylinder engine as an example, as described above. Although only the first cylinder is representatively shown as the cylinder 10, the second to fourth cylinders of the internal combustion engine are similarly configured.
As described above, the internal combustion engine is provided with a throttle valve 1 for limiting the intake air amount, and the throttle valve 1 is electronically controlled by a throttle opening control signal from the throttle control unit 7B.

The TPS provided in the throttle actuator 6 transmits a throttle opening detection signal (TH) to the throttle control unit 7B.
The throttle control unit 7B receives the engine speed signal (Ne), crank angle signal (CA), target intake air amount signal, atmospheric pressure signal, and intake air temperature signal from the engine control unit 8B.
On the other hand, a fuel control intake air amount signal is input to the engine control unit 8B from the throttle control unit 7B.

The throttle control unit 7B determines the target throttle opening degree THT based on the throttle opening degree detection signal (TH), the fuel control intake air amount and the target intake air amount signal, as well as the engine speed detection signal (Ne), the crank Based on the angular signal (CA), the atmospheric pressure, the intake air temperature, and the like, an estimation process such as an intake air amount for fuel control is executed.
In FIG. 23, the throttle downstream pressure corresponds to the pressure on the throttle downstream side 9B.

The engine control unit 8B receives the fuel control intake air amount signal, the accelerator depression amount detection signal, and the crank angle detection signal as well as the atmospheric pressure detection signal from the atmospheric pressure sensor 15 and the temperature sensor 16. An intake air temperature detection signal is input.
The atmospheric pressure sensor 15 and the temperature sensor 16 are installed in an intake passage between the throttle valve 1 and the air cleaner 13.

As a result, the engine control unit 8B outputs a fuel injection control signal for the fuel injection valve 2 of each cylinder 10 and an ignition control signal for the ignition plug 11 of each cylinder 10, and to the throttle control unit 7B. The engine speed signal, the crank angle signal, the target intake air amount signal, the atmospheric pressure signal, and the intake air temperature signal are output.
The engine control unit 8B detects the engine speed Ne and the crank angle CA from the crank angle detection signal, determines the target intake air amount from the accelerator depression amount, the fuel control intake air amount, and the like, and the fuel control intake air amount. The fuel injection amount is determined from the target air-fuel ratio and the like.

The fuel injection valve 2 injects fuel independently for each cylinder 10.
Also in this case, similarly to the above, the throttle opening THE from the predetermined time A to the intake valve closing completion time (crank angle IVC) is estimated and estimated. However, the configuration and formula are the same as described above. Description is omitted.

Further, in the third embodiment of the present invention, as shown in FIG. 24, the throttle control unit 7B is arranged in each cylinder considering the volume change from the upstream side of the throttle in the collective throttle system in order to reduce the calculation load. The "collection part throttle system model" that models the intake passage between the two is used.
Thus, only the flow rate through the throttle valve 1 can be estimated, and the throttle downstream pressure, the cylinder pressure, the intake air amount, and the like can be estimated.

Here, the collective throttle system model used in the third embodiment of the present invention will be described with reference to FIG.
In FIG. 24, IVO and IVC are crank angles similar to those described above (see FIGS. 5 and 6).
Similarly to the above, the intake air temperature is constant (temperature T1 in all regions), and the subscripts “1” and “2” attached to the pressure P, volume V, and temperature T are “throttle valves”, respectively. "Upstream side", "Throttle downstream side to intake valve 3".
The subscripts “4” to “7” indicate “inside the first cylinder” to “inside the fourth cylinder”, respectively.

  The collective part throttle system model shown in FIG. 24 is a model for estimating the throttle passage flow rate, the throttle downstream pressure, the in-cylinder pressure, the intake air amount, and the like. The throttle upstream side, the throttle opening, and the throttle downstream side 9B To the intake valve 3 and a region to each cylinder through the throttle downstream side 9B.

In FIG. 24, the region from the throttle upstream side to the throttle downstream side 9B has the same configuration as the intake valve closed model (FIG. 5) and the intake valve open model (FIG. 6).
That is, the throttle upstream side is configured by the throttle upstream pressure P ₁ and the intake air temperature T ₁ , the throttle opening is configured by the throttle flow path area _AT, and the intake air passing through the throttle opening is the throttle upstream pressure. It receives the pressure from P ₁ and the throttle downstream pressure _{P 2.}
Further, the throttle downstream side 9B is constituted by a throttle downstream pressure P ₂ , a throttle downstream volume V _2, and an intake air temperature T ₁ .

On the other hand, in the cylinder shown in FIG. 24, the in-cylinder configuration of each cylinder 10 is similar to the in-cylinder structure in the above-described intake valve opening model (FIG. 6), and in-cylinder pressures P _{4 to} P ₇ It is constituted by an internal volume V _{4 to} V ₇ and an intake air temperature T ₁ .
Here, the in-cylinder volumes V _{4 to} V ₇ change due to the vertical movement of the piston in each cylinder 10 (however, it can be ignored while the intake valve 3 is closed).
Further, the cylinder pressure P ₄ to P _7, except immediately after the valve opening start time (crank angle IVO), a throttle downstream pressure P2 and the other cylinder pressure opening the intake valve is pressure equilibrium state (however, the intake It can be ignored while valve 3 is closed).

In other words, the in-cylinder volumes V _{4 to} V ₇ change according to the crank angle CA. For the in-cylinder pressures P _{4 to} P ₇ , except for the valve opening start time (IVO) of the intake valve 3, cylinder pressure of each cylinder open and the throttle downstream pressure P ₂ is assumed to be balanced.
The throttle upstream pressure P ₁ is handled as almost atmospheric pressure, and the intake air temperature T ₁ is handled as constant throughout the area.

  When estimating the throttle passage flow rate at the start of opening of the intake valve 3 of a certain cylinder 10, the throttle control unit 7 B first determines that “the throttle downstream pressure and the intake valve 3 are at the start of opening of the intake valve 3. It is necessary to estimate the pressure when the in-cylinder pressure of each open cylinder 10 and the in-cylinder pressure of the cylinder to be controlled are balanced.

  This is because the exhaust stroke immediately before the start of opening of the intake valve 3 is an exhaust stroke, so the cylinder in the cylinder to be controlled is almost at atmospheric pressure, and when the intake valve 3 is opened in this state, the cylinder at almost atmospheric pressure and the negative pressure Are in a state of communication with each other, “the throttle downstream pressure and the in-cylinder pressure of each cylinder 10 in which the intake valve 3 is open”. This is because the in-cylinder pressure of the cylinder to be controlled is in an equilibrium state.

  The throttle downstream pressure after pressure equilibrium and the in-cylinder pressure of each cylinder in which the intake valve 3 is open are estimated from the following equation (11) based on the gas equation of state.

  However, in Equation (11), each variable indicates the following.

By the way, as with the intake valve opening model described above (see FIG. 6), the throttle downstream pressure and the in-cylinder pressure change due to the change in the in-cylinder volume of each cylinder.
Therefore, when estimating the flow rate through the throttle, first, assuming that there is no flow rate from the throttle valve 1 during the predetermined period ΔCA, the throttle downstream pressure and the cylinder pressure when the cylinder volume of each cylinder changes. Is estimated by the following equation (12), and the throttle passage flow rate is estimated as the following equations (13) and (14) based on the estimated throttle downstream pressure and in-cylinder pressure.

  However, in Equation (11), each variable indicates the following.

を上記式（１１）で推定したうえで、その推定値を上記式（１２）における所定周期ΔＣＡ前のスロットル下流圧力および吸気弁３が開いている各気筒の筒内圧力

として、単位時間当りスロットル通過流量を推定する。 It should be noted that the equations (13) and (14) are similar to the equations (2) and (3) described above, and are indicators for whether or not the speed of the intake air passing through the throttle valve 1 has reached the speed of sound (throttle valve 1 The pressure is divided according to the upstream and downstream pressure ratio).
Further, when the intake valve 3 of any one of the first to fourth cylinders begins to open, the estimated downstream pressure at the crank angle IVO at the start of valve opening of the cylinder where the intake valve 3 opens.

Is estimated by the above equation (11), and the estimated value is the throttle downstream pressure before the predetermined period ΔCA in the above equation (12) and the in-cylinder pressure of each cylinder where the intake valve 3 is open.

As a result, the flow rate through the throttle per unit time is estimated.

と、スロットル下流容積Ｖ_２と現時点の「吸気弁３が開いている各気筒の筒内容積

」との和と、吸入空気温度Ｔ_１とから、気体の状態方程式を用いて、現時点のスロットル下流圧力および吸気弁が開いている各気筒の筒内圧力を推定する。 The throttle passage flow rate per unit time, the predetermined period ΔCA, the current throttle downstream pressure (assuming that there is no flow rate from the throttle valve 1), and the in-cylinder pressure of each cylinder in which the intake valve 3 is open

And the throttle downstream volume V ₂ and the current “in-cylinder volume of each cylinder with the intake valve 3 open”

”And the intake air temperature T ₁ , the current throttle downstream pressure and the in-cylinder pressure of each cylinder in which the intake valve is open are estimated using the gas state equation.

The estimated throttle downstream pressure and the in-cylinder pressure of each cylinder in which the intake valve 3 is open are then used to estimate the throttle downstream pressure and the in-cylinder pressure of each cylinder in which the intake valve 3 is open after a predetermined period ΔCA. The basis of
Thereafter, the above process is executed every predetermined period ΔCA.

Next, referring to the explanatory diagrams of FIGS. 33 and 34 together with the flowcharts of FIGS. 25 to 32, the third intake air amount estimation flow executed by the throttle control unit 7B according to the third embodiment of the present invention will be described. explain.
FIG. 33 is an explanatory diagram showing maps of the valve timing (upper stage) and the predetermined timing A (lower stage) of the intake valve 3, and FIG. 34 is an explanatory diagram showing a speed term map (three-dimensional map).

In the third intake air amount estimation flow, the collective part throttle system model shown in FIG. 24 is used as described above.
The throttle control unit 7B incorporates a valve timing map of each intake valve 3 (used for determination of intake valve opening / closing in FIG. 33) using the crank angle CA as a parameter.

The third intake air amount estimation flow is executed when a trigger sent from the engine control unit 8B to the throttle control unit 7B is received every predetermined cycle ΔCA based on the crank angle.
That is, the estimated estimated downstream pressure, the estimated estimated in-cylinder pressure and the intake air amount for fuel control are estimated and estimated by the intake air amount predictive estimation control, and the estimated downstream pressure and estimated in-cylinder pressure are estimated by the real-time downstream pressure estimation control. Further, the predicted estimated throttle opening is predicted and estimated by the throttle opening predictive estimation control.

Here, the processing procedure of the third intake air amount estimation flow shown in FIGS. 25 to 32 will be schematically described with reference to mathematical expressions.
The third intake air amount estimation flow includes control logic (FIGS. 30 to 32) for performing intake air amount prediction estimation control, control logic (steps s201, s202, s204 to s223) for performing real-time downstream pressure estimation control, The control logic is the same as (step s65 in FIG. 12, see FIG. 15), and includes control logic (step s200) that corrects intake air temperature and atmospheric pressure.

In the intake air amount prediction estimation control and the real-time downstream pressure estimation control, the predicted estimated downstream pressure, the fuel control intake air amount, and the like are calculated based on the above equations (11) to (14) and the gas state equation.
In the third intake air amount estimation flow, the flow varies depending on the throttle passage flow rate during a predetermined period ΔCA based on the throttle passage flow rate per unit time and the gas state equation shown in the above formulas (13) and (14). The throttle downstream pressure is calculated from the following equation (15).

  However, in the equation (15), each variable indicates the following.

Here, the area term indicates the throttle flow path area, and is calculated from an area term map (see FIG. 17) using the throttle opening TH as a parameter, as in the first embodiment.
The map value is determined by actually measuring the flow rate through the throttle and calculating the map value based on the measured value or by calculating from the projected area of the throttle opening.
In the formula (15), each variable represents the following.

Here, the speed term is obtained by multiplying “the flow rate per unit area of the throttle unit and the flow rate per unit time” by the gas constant and the intake air temperature, and the throttle downstream pressure P ₂ —old and the throttle upstream pressure before the predetermined period ΔCA. the ratio _"P 2 _old / _{P 1"} with P _1, consisting of 3-dimensional map as a parameter the ratio _"P ¹ 2 / _{T 1"} of the square of the throttle upstream pressure _{P 1} and the intake air temperature _{T 1} of It is calculated based on the speed term map (see FIG. 34).

In the velocity term map shown in FIG. 34, a characteristic diagram on the YY ′ axis (see the two-dot chain line in the lower left) when “P ₁ ² / T ₁ ” is viewed as a fixed parameter (the horizontal axis indicates “P in ₂ _old / _{P 1} "), the same tendency as FIG. 18 described above.
On the other hand, when “P ₂ _old / P ₁ ” is viewed as a fixed parameter, a characteristic diagram on the XX ′ axis (see the two-dot chain line in the upper right) (the horizontal axis is “P ₁ ² / T ₁ ”) Then, it becomes the relationship of the proportional increase according to a linear function.
Moreover, the variables in Formula (15) are as follows.

  Note that the value of the volume term (cylinder volume of each cylinder) varies according to the crank angle CA by the vertically moving piston as described above. Therefore, the in-cylinder volume Vk_new (k = 4 to 7: where the intake valve 3 is closed) and the cylinders in which the intake valve 3 is closed (including cylinders that have reached the intake valve closing completion time IVC). The cylinder that has reached the valve start time IVO is ignored), as described above, based on the in-cylinder volume map (see FIG. 19) with the crank angle CA as a parameter.

Here, the in-cylinder volume of each cylinder is expressed in a form in which the phase is simply shifted, although the values differ at the same time. Therefore, the in-cylinder volume map with the crank angle CA as a parameter calculates the in-cylinder volume of the first cylinder, and the in-cylinder volume of the second to fourth cylinders has a phase of the crank angle CA. The displacement is calculated using the in-cylinder volume map.
For example, when obtaining the in-cylinder volume of the third cylinder, the in-cylinder volume map is referred to using a value obtained by retarding the crank angle CA by 180 ° as a parameter.
Furthermore, the variables in equation (15) are as follows.

Further, as described in the above equation (11), when estimating the throttle passage flow rate at the valve opening start time IVO of the intake valve 3 of any cylinder 10, first, at the valve opening start time IVO of the intake valve 3. It is necessary to estimate the pressure when the throttle downstream pressure and the cylinder pressure at which the intake valve 3 is open are balanced with the cylinder pressure of the cylinder to be controlled.
Therefore, in the third intake air amount estimation flow, the pressure when the balance is achieved as described above is calculated by the following equation (16) based on the aforementioned equation (11).

  However, in the equation (16), each variable indicates the following.

Further, when calculating the throttle downstream pressure and the in-cylinder pressure of each cylinder in which the intake valve 3 is open based on the collective throttle system model (FIG. 24) as in the above-described equation (12), a predetermined period is used. Assuming that there is no flow rate from the throttle valve 1 between ΔCA, it is necessary to calculate the throttle downstream pressure after the cylinder volume of each cylinder changes and the cylinder pressure of each cylinder where the intake valve 3 is open. is there.
Therefore, in the third intake air amount estimation flow, the throttle downstream pressure and the in-cylinder pressure after the in-cylinder volume of each cylinder 10 is changed are calculated by the following equation (17).

  However, in the equation (17), each variable indicates the following.

Thus, using the above equations (15) to (17), the throttle downstream pressure and the in-cylinder pressure of each cylinder in which the intake valve 3 is open are estimated or predicted.
Further, the estimated intake air amount sucked into the cylinder at the time when the intake valve is closed is predicted and estimated from the estimated fuel control in-cylinder pressure, the in-cylinder volume, and the intake air temperature using the gas state equation. be able to.

Hereinafter, the third intake air amount estimation flow will be described in detail for each step in the flowchart.
In the third intake air amount estimation flow, assuming that the current crank angle in the above formulas (15) to (17) is CA1 and the calculation cycle is ΔCA1, values are substituted into CA1 and ΔCA1.
Each step s22, s64, s65 is assumed to execute the same processing as described above (see the first embodiment).

In FIG. 25, the throttle control unit 7B first reads the atmospheric pressure and the intake air temperature (detected values of the atmospheric pressure sensor 15 and the temperature sensor 16) from the engine control unit 8B (step s200), and the read atmospheric pressure sensor value. the substituted into P _1, substitutes the intake air temperature sensor value T _1.

Subsequently, it is determined whether or not the engine is operating (step s201). If it is determined that the engine is stopped (that is, NO), the intake flow rate is accumulated in the throttle downstream volume via the throttle valve 1, and the throttle downstream pressure is determined. Is restored to atmospheric pressure, “P ₂ _old = P ₁ ” is executed (step s203) in the same manner as step s3 described above (FIG. 7).
Then, the process proceeds to FIG. 7 via the node “7”, ends the third intake air amount estimation flow, and waits until the next trigger is received.

  On the other hand, if it is determined in step s201 that the engine is operating (that is, YES), the crank angle CA and the engine speed Ne are read from the engine control unit 8B, and the throttle opening TH is read from the throttle actuator 6 (step s202). ) Subsequently, referring to the valve timing map of the intake valve of each cylinder (upper stage in FIG. 33), the cylinder of any cylinder during the period from the previous cycle (= CA−ΔCA) to the current time (= CA). It is determined whether or not the crank angle IVC or IVO has been reached (step s204).

If it is determined in step s204 that the IVC or IVO of any cylinder has been reached (that is, YES), the process proceeds to a process (step s206) described later.
On the other hand, if it is determined in step s204 that none of the cylinders has reached IVC or IVO (that is, NO), the process proceeds to the process in FIG. 27 via node “1”, and in steps s205 and s223, Real time downstream pressure estimation control is executed to calculate the estimated downstream pressure at the crank angle CA and the estimated in-cylinder pressure of each cylinder in which the intake valve 3 is open.

In FIG. 27, first, “ΔCA1 = ΔCA” and “CA1 = CA” are executed (step s205), and then the estimated downstream pressure calculation is executed (step s223).
The estimated downstream pressure calculation (step s223) includes steps s230 to s241 as shown in FIG.

を算出する（ステップｓ２３０）。
続いて、現時点のクランク角ＣＡ１と筒内容積マップ（図１９参照）とに基づいて、クランク角ＣＡ１での吸気弁３の開いている各気筒（ＩＶＣに達した気筒を含む）の筒内容積の和

を算出するとともに、算出した筒内容積の和を今回筒内容積Ｖｎｅｗに代入し、今回筒内容積Ｖｎｅｗとスロットル下流容積Ｖ_２とから体積項

を算出する（ステップｓ２３１）。 In FIG. 28, first, a time term is calculated from the engine speed Ne and a predetermined cycle ΔCA1.

Is calculated (step s230).
Subsequently, based on the current crank angle CA1 and the in-cylinder volume map (see FIG. 19), the in-cylinder volume of each cylinder (including the cylinder that has reached IVC) at which the intake valve 3 is open at the crank angle CA1. Sum of

And calculates a sum of the calculated cylinder volume is assigned to this cylinder volume Vnew, volume terms from this cylinder volume Vnew and the throttle downstream volume V ₂ Metropolitan

Is calculated (step s231).

Next, using the above equation (17), the estimated downstream pressure at the crank angle CA1 (assuming that there is no flow rate from the throttle valve 1) and the estimated in-cylinder of each cylinder in which the intake valve 3 is open The pressure is calculated (step s232).
Subsequently, the following processing is executed (step s233) similarly to step s32 described above (FIG. 10).

と速度項マップ（図３４）とから、速度項

を算出するとともに（ステップｓ２３４）、スロットル開度ＴＨと面積項マップ（図１７）とから、面積項

を算出する（ステップｓ２３５）。 In addition, the aforementioned ratio

And the velocity term map (FIG. 34)

Is calculated (step s234), and the area term is calculated from the throttle opening TH and the area term map (FIG. 17).

Is calculated (step s235).

Further, from equation (15), the estimated downstream pressure at the crank angle CA1 and the estimated in-cylinder pressure of each cylinder in which the intake valve 3 is open are calculated (step s236), and then the valve timing map of each intake valve 3 is calculated. From (the upper stage in FIG. 33), it is determined whether or not the crank angle CA1 is IVC or IVO of any of the first to fourth cylinders (step s237).
If it is determined in step s237 that the crank angle CA1 is not IVC or IVO of any of the first to fourth cylinders (that is, NO), the current in-cylinder volume Vnew is set as the previous value as follows. The substitution process is executed (step s238).

  Subsequently, similarly to step s233, the following processing is executed (step s241).

を算出する（ステップｓ２３９、ｓ２４０）。
この場合、今回筒内容積Ｖｎｅｗが「吸気弁３が開いている各気筒（ＩＶＣに達した気筒を含む）の筒内容積の和」であるのに対し、前回筒内容積Ｖｏｌｄは、「吸気弁３が開いている各気筒（ＩＶＯに達した気筒を含む）の筒内容積の和」であって、Ｖｎｅｗとは定義が異なる。 Thereafter, the processing routine in FIG. 28 is terminated, and the process proceeds to a determination process (step s224) in FIG. 27 described later.
On the other hand, if it is determined in step s237 that the crank angle CA1 is IVC or IVO of any of the first to fourth cylinders (ie, YES), the in-cylinder volume map (FIG. 19) is used. ,

Is calculated (steps s239 and s240).
In this case, the current in-cylinder volume Vnew is “the sum of the in-cylinder volumes of each cylinder (including cylinders that have reached IVC) in which the intake valve 3 is open”, whereas the previous in-cylinder volume Vold is “intake This is the sum of the in-cylinder volumes of the cylinders (including cylinders that have reached IVO) in which the valve 3 is open, and the definition is different from Vnew.

と代入することができないので、ステップｓ２３９およびｓ２４０のように、ステップｓ２３８の処理とは場合分けしている。
すなわち、クランク角ＣＡ１と筒内容積マップとからクランク角ＣＡ１での「吸気弁３が開いている各気筒（ＩＶＣを含む）の筒内容積の和」

を算出したうえで（ステップｓ２３９）、以下の処理を実行する（ステップｓ２４０）。 Therefore, when the crank angle CA1 is IVC or IVO of any of the first to fourth cylinders, simply

Therefore, the processing of step s238 is divided into cases as in steps s239 and s240.
That is, from the crank angle CA1 and the in-cylinder volume map, “the sum of the in-cylinder volume of each cylinder (including IVC) in which the intake valve 3 is open” at the crank angle CA1.

Is calculated (step s239), and the following processing is executed (step s240).

  Thereafter, the process proceeds to step s241, where the above-described processing is executed as follows, and the process proceeds to determination step s224 (described later) in FIG.

On the other hand, returning to FIG. 25, if it is determined in step s204 that the IVC or IVO of any cylinder has been reached (ie, YES), the predetermined period ΔCA is divided for each IVC or IVO, as follows. Then, calculation processing such as estimated downstream pressure is executed (steps s206 to s223).
The reason for executing this calculation process is, for example, as described in relation to the aforementioned equations (11) to (17), for example, at the valve opening start time IVO, the in-cylinder pressure of the cylinder at which the intake valve 3 starts to open and the “throttle This is because it is necessary to calculate the pressure when the downstream pressure and the in-cylinder pressure of each cylinder in which the intake valve 3 is open are balanced.

First, referring to the valve timing map of the intake valve 3 of each cylinder (upper stage in FIG. 33), the IVO that has reached the earliest of the IVCs or IVOs of any of the cylinders that have been reached. Whether or not (step s206).
If it is determined in step s206 that IVC has arrived earlier (that is, NO), the process proceeds to a process described later (step s215).

On the other hand, if it is determined in step s206 that IVO has arrived earlier (that is, YES), in order to calculate the estimated downstream pressure at the crank angle IVO that has reached earlier (hereinafter referred to as “IVO_F”), “ΔCA1 = IVO_F− (CA−ΔCA)” and “CA1 = IVO_F” are executed (step s207).
Similarly to the above (step s223 in FIG. 27), the estimated downstream pressure is calculated (step s208), and the estimated downstream pressure at the crank angle IVO_F and the estimated in-cylinder of each cylinder in which the intake valve 3 is open. The pressure is calculated (step s208), and the IVO calculation is executed (step s209).

The IVO calculation (step s209) includes steps s242 and s243 as shown in FIG.
In FIG. 29, first, “the throttle downstream pressure and the in-cylinder pressure of each cylinder in which the intake valve 3 is open” and the intake valve 3 are opened at the crank angle IVO (here, IVO_F reached earlier) at the valve opening start time. The pressure when the in-cylinder pressure of the starting cylinder is balanced is estimated by the calculation process using the above-described equation (16) (step s242).
Subsequently, similarly to steps s233 and s241, the following processing is executed (step s243).

Thereafter, the processing routine of FIG. 29 is ended, and the process proceeds to step s210 in FIG. 25, and after reaching the crank angle IVO_F, whether or not the IVC of any cylinder has been reached before reaching the crank angle CA. Is determined (step s210).
If it is determined in step s210 that the IVC of any cylinder is not reached (that is, NO), the process proceeds to the process in FIG. 26 (step s214) described later via the node “3”.

  On the other hand, if it is determined in step s210 that the IVC of any cylinder has been reached (that is, YES), the process proceeds to the process in FIG. 26 via the node “2”, and the crank angle IVC ( Hereinafter, “ΔCA1 = IVC_L−IVO_F” and “CA1 = IVC_L” are executed in order to calculate the estimated downstream pressure at “IVC_L” (step s211).

Subsequently, the estimated downstream pressure calculation similar to that described above (step s223 in FIG. 27) is executed to calculate the estimated downstream pressure at the crank angle IVC_L and the estimated in-cylinder pressure of each cylinder in which the intake valve 3 is open. (Step s212).
Further, in order to calculate the estimated downstream pressure at the crank angle CA, etc., “ΔCA1 = CA−IVC_L” and “CA1 = CA” are executed (step s213), and in FIG. 27 via the node “6”. Proceeding to step s223, after calculating the estimated downstream pressure at the crank angle CA and the estimated in-cylinder pressure of each cylinder in which the intake valve 3 is open, the process proceeds to step s224 (described later).

On the other hand, when it is determined in step s210 in FIG. 25 that the IVC of any cylinder is not reached (ie, NO) after reaching IVO_F until reaching the crank angle CA, the step in FIG. Proceeding to s214, “ΔCA1 = CA−IVO_F” and “CA1 = CA” are executed in order to calculate the estimated downstream pressure or the like at the crank angle CA.
Subsequently, the process proceeds to step s223 in FIG. 27 via the node “6”, and after calculating the estimated downstream pressure at the crank angle CA and the estimated in-cylinder pressure of each cylinder in which the intake valve 3 is open, the process proceeds to step s224. move on.

  On the other hand, if it is determined in step s206 in FIG. 25 that IVC or IVO of any of the cylinders that have arrived has reached IVC earlier (that is, NO), IVC ( Hereinafter, “ΔCA1 = IVC_F− (CA−ΔCA)” and “CA1 = IVC_F” are executed in order to calculate the estimated downstream pressure at “IVC_F” (step s215).

Similarly to the above (Steps s208, s223), the estimated downstream pressure is calculated (Step s216), and the estimated downstream pressure at the crank angle IVC_F and the estimated in-cylinder pressure of each cylinder where the intake valve 3 is open are calculated. calculate.
Subsequently, it is determined whether or not the IVO of any cylinder has been reached after reaching IVC_F until reaching the crank angle CA (step s217).

If it is determined in step s217 that the IVC of any cylinder is not reached (ie, NO), the process proceeds to the process in FIG. 26 (step s222) described later via the node “5”.
On the other hand, if it is determined in step s217 that the IVO of any cylinder has been reached (that is, YES), the process proceeds to step s218 in FIG. 26 via the node “4”, and has reached after the crank angle IVC_F. In order to calculate the estimated downstream pressure at the crank angle IVO (hereinafter referred to as “IVO_L”), the processes of “ΔCA1 = IVO_L−IVC_F” and “CA1 = IVO_L” are executed.

Subsequently, in the same manner as described above (step s223), the estimated downstream pressure is calculated (step s219), and the estimated downstream pressure at the crank angle IVO_L reached after IVC_F and each cylinder in which the intake valve 3 is open are determined. Calculate the estimated cylinder pressure.
Similarly to the above (step s209), the IVO calculation is executed (step s220), and the “cylinder angle IVO (here, IVO_L)” indicates that “the throttle downstream pressure and the cylinder in each cylinder in which the intake valve 3 is open” The pressure when the “pressure” and the in-cylinder pressure of the cylinder at which the intake valve 3 begins to open is balanced is estimated.

Subsequently, in order to calculate the estimated downstream pressure at the crank angle CA and the like, processing of “ΔCA1 = CA−IVO_L” and “CA1 = CA” is executed (step s221), and the process is performed via the node “6”. The process proceeds to step s223 in step 27.
Thereafter, as described above, the estimated downstream pressure at the crank angle CA and the estimated in-cylinder pressure of each cylinder in which the intake valve 3 is open are calculated (step s223), and the process proceeds to step s224.

On the other hand, if it is determined in step s217 that the IVC of any cylinder is not reached (ie, NO) after reaching IVC_F until the crank angle CA is reached, the process proceeds to step s222 in FIG. In order to calculate the estimated downstream pressure and the like at the crank angle CA, the processing of “ΔCA1 = CA−IVC_F” and “CA1 = CA” is executed.
Thereafter, the process proceeds to step s223 in FIG. 27 via the node “6”, and after calculating the estimated downstream pressure at the crank angle CA and the estimated in-cylinder pressure of each cylinder in which the intake valve 3 is open as described above. The process proceeds to step s224.

As described above, the estimated downstream pressure and the estimated in-cylinder pressure of each cylinder in which the intake valve 3 is open are calculated by the real-time downstream pressure estimation control including steps s201 to s223.
Subsequently, in steps s224 to s225 in FIG. 27, the determination process of the intake air amount prediction estimation control, the intake air amount prediction estimation control, and the throttle opening prediction estimation control are executed.

First, in the determination process in FIG. 27, it is determined whether or not the crank angle CA is the predetermined timing A of any cylinder (step s224).
The predetermined time A of each cylinder is calculated from the engine speed Ne and a predetermined time A map (a map using the lower engine speed Ne in FIG. 33 as a parameter).
In FIG. 33, as can be seen from the lower map, the predetermined time A of each cylinder is set to the intake air amount prediction estimation control in order to secure the estimation processing time as the engine speed Ne (see the one-dot chain line) increases. The start period is shifted by a predetermined period ΔCA in a direction that is advanced.

If it is determined in step s224 that the crank angle CA is not the predetermined timing A of any cylinder (that is, NO), the process proceeds to a determination process (step s226) described later.
On the other hand, if it is determined in step s224 that the crank angle CA is the predetermined timing A of any cylinder (that is, YES), the intake air for fuel control by the intake air amount prediction estimation control and the throttle opening prediction estimation control is determined. An amount calculation process is executed (step s225).

  The fuel control intake air amount calculation process (step s225) includes the processes shown in FIGS. 30 to 32 (steps s244 to s274, s64, and 65).

  First, in steps s244 to s246 and s64 in FIG. 30, a preparatory process for intake air amount prediction estimation control and throttle opening prediction estimation control is executed.

  Further, in steps s247 to s271 and s65 in FIG. 30 to FIG. 32, after calculating the predicted estimated throttle opening by the throttle opening predictive estimation control, the intake air amount prediction estimation control performs the control target cylinder (for fuel control). The estimated estimated downstream pressure at the crank angle IVC of the intake air amount calculation target cylinder) and the estimated estimated in-cylinder pressure (= downstream pressure for fuel control and in-cylinder pressure for fuel control) of each cylinder in which the intake valve 3 is open. calculate.

Further, after calculating the fuel control intake air amount from the fuel control cylinder pressure in step s272 in FIG. 32, the fuel control intake air amount calculation processing (step in FIG. 27) is performed via steps s273 and s274. s225) is ended, and the process proceeds to step s226.
Next, each step of the calculation process of the intake air amount for fuel control will be described with reference to equations together with FIGS.

In FIG. 30, first, processing of “CA ′ = CA” and “THE = TH” is executed (step s244).
Here, CA ′ is a crank angle used when executing the intake air amount prediction estimation control and the throttle opening prediction estimation control, and THE is a predicted estimated throttle opening used during the intake air amount prediction estimation control.

  Subsequently, similarly to the above-described step s43, the throttle downstream pressure at the present time (predetermined time A) is set as follows (step s245).

  Further, as described below, the in-cylinder volume at the present time (predetermined time A) is set (step s246).

  Further, by executing the above processing, “the estimated downstream pressure and the estimated in-cylinder pressure of each cylinder in which the intake valve 3 is open” and “the intake valve 3 is opened” at the present time (= the predetermined timing A of the cylinder to be controlled). The sum of in-cylinder volumes of each cylinder (including cylinders that have reached IVO) is stored.

Further, the slope DAB of linear interpolation used in the throttle opening prediction estimation control is calculated from the above equation (20) (step s64), and the process proceeds to the next loop control (steps s247 to s271 and s65).
Steps s247 to s271 and s65 are executed in a loop until the crank angle CA ′ reaches the IVC of the cylinder to be controlled.

  First, in FIG. 30, “CA ′ = CA ′ + ΔCA” is executed (step s248), the crank angle CA ′ is advanced by a predetermined period ΔCA, and then the same processing as described above (see FIGS. 12 and 15). (Step s65) is executed, and the predicted estimated throttle opening THE is calculated by calculating the predicted estimated throttle opening.

の算出において、スロットル開度ＴＨではなく予測推定スロットル開度ＴＨＥを用いる点とを除けば、基本的に図２５〜図２７の処理（ステップｓ２０４〜ｓ２２３）と同様である。
すなわち、上記各フローチャートの処理は、以下の（ｄ）、（ｅ）のように対応するので、ステップｓ２４９〜ｓ２７０については詳述を省略する。 In the subsequent processing (steps s249 to s270), as can be understood by comparing the flowcharts of FIGS. 25 to 27 and FIGS. 30 to 32, the crank angle CA is CA ′ and the estimated downstream pressure is calculated. Area terms in

The calculation is basically the same as the processing in FIGS. 25 to 27 (steps s204 to s223) except that the estimated estimated throttle opening THE is used instead of the throttle opening TH.
That is, the processes in the flowcharts correspond to the following (d) and (e), and thus detailed description of steps s249 to s270 is omitted.

(D) “Steps s249, s250, and s270” do not reach the IVO and IVC of any cylinder from the above-mentioned “Steps s204, s205, and s223 (from the previous crank angle CA−ΔCA to the current crank angle CA). State) ”.
(E) “Steps s249, s251 to s255, s260, s270” reaches the IVO of any cylinder during the above-mentioned “Steps s204, s206 to s210, s214, s223 (CA−ΔCA to CA). State) ”.

  In addition, regarding the above-mentioned “steps s204, s206 to s213, s223 (a state in which, from CA−ΔCA to CA, first, after reaching IVO of any cylinder, then reaching IVC of any cylinder)”. The purpose of the intake air amount predictive estimation control is to calculate the predicted estimated downstream pressure at the IVC of the cylinder to be controlled and the predicted estimated in-cylinder pressure of each cylinder in which the intake valve 3 is open.

  Therefore, after the above-mentioned “steps s204, s206 to s213, s223” correspond to “steps s249, s251 to s257, s259, s270” in FIGS. 30 to 32, step s257 (crank in FIG. 31). After execution of the predicted estimated downstream pressure at the angle IVC_L and the predicted estimated in-cylinder pressure of each cylinder in which the intake valve 3 is open, step s258 (whether the crank angle IVC_L is the crank angle IVC of the cylinder to be controlled) Control logic to determine whether or not.

  Accordingly, if it is determined in step s258 in FIG. 31 that the crank angle IVC_L is not the crank angle IVC of the control target cylinder (ie, NO), the process proceeds to step s259, and IVC_L is the IVC of the control target cylinder (ie, If YES, the process proceeds to step s271 in FIG. 32 via the node “11” to exit the loop control.

  Similarly, “steps s249, s251, s261, s262, s264 to s268, s270” in FIG. 30 to FIG. 32 are the same as “steps s204, s206, s215 to s221, s223 (between CA−ΔCA and CA). First, after reaching the IVC of any cylinder and then reaching the IVO of any cylinder), step s262 (the predicted estimated downstream pressure at IVC_F and the intake valve 3 is opened) In step s263 in FIG. 31, a determination control process similar to that in step s258 is incorporated after the calculation process of the predicted estimated in-cylinder pressure of each cylinder.

  Further, “Steps s249, s251, s261, s262, s264, s269, s270” is the same as the above-mentioned “Steps s204, s206, s215 to s217, s222, s223 (any cylinder between CA−ΔCA and CA). In step s263, after step s262 (calculation processing of the predicted estimated downstream pressure in IVC_F and the predicted estimated in-cylinder pressure of each cylinder in which the intake valve 3 is open) A determination control process similar to that in step s258 is incorporated.

の算出においては、スロットル開度ＴＨではなく、予測推定スロットル開度ＴＨＥが用いられている。 Furthermore, as described above, the area term in step s235 (see FIG. 28) in the estimated downstream pressure calculation in steps s253, s257, s262, s266, and s270.

In the calculation of, not the throttle opening TH but the predicted estimated throttle opening THE is used.

By the above estimation calculation, the estimated estimated downstream pressure at the IVC of the cylinder to be controlled and the estimated estimated in-cylinder pressure of each cylinder in which the intake valve 3 is open (= the downstream pressure for fuel control and the in-cylinder pressure for fuel control) were calculated. Thereafter, the process proceeds to step s272 in FIG.
In step s272, based on the cylinder pressure for fuel control, the cylinder volume at the IVC of the cylinder to be controlled and the intake air temperature, the intake air amount for fuel control is calculated using the gas state equation, and the calculated fuel is calculated. After the control intake air amount is transmitted to the engine control unit 8B, the process proceeds to step s273.

In step s273, as in step s63 described above, the throttle downstream pressure at the predetermined time A is set as follows as the throttle downstream pressure P ₂ _old before the predetermined period ΔCA.

  Subsequently, in step s274, the in-cylinder volume at the present time (predetermined time A) is set as the previous value as follows.

これにより、次のトリガを受け取った後に実行するリアルタイム下流圧推定制御に備えた状態として、燃料制御用吸入空気量の計算処理ルーチンを終了し、図２７内のステップｓ２２６に進む。

As a result, in preparation for real-time downstream pressure estimation control to be executed after receiving the next trigger, the fuel control intake air amount calculation processing routine is terminated, and the routine proceeds to step s226 in FIG.

In step s226, it is determined whether or not the crank angle CA is the calculation time of the predetermined time A of each cylinder.
The calculation time of the predetermined time A is set to, for example, the TDC (top dead center crank angle) of the intake stroke of the first cylinder, and is set to have a frequency of about once every four stroke cycles.
If it is determined in step s226 that the crank angle CA is not the predetermined time A (calculation time) (that is, NO), the process proceeds to step s22 similar to the above (see FIG. 9).

  On the other hand, if it is determined in step s226 that the crank angle CA is the predetermined time A (calculation time) (that is, YES), the predetermined time A of each cylinder is set to the engine speed Ne and the predetermined time A map (in FIG. 33). (Refer to the lower stage) (step s227), and the process proceeds to step s22.

  In step s22, the following processing is executed as described above (Embodiment 1).

As a result, the current throttle opening is stored, the third intake air amount estimation flow is terminated, and the process waits until the next trigger is received.
Hereinafter, the throttle control unit 7B performs the above processing from the start to the stop of the internal combustion engine.

  As described above, the internal combustion engine control apparatus (see FIG. 23) according to Embodiment 3 of the present invention includes a plurality of independent intake pipes corresponding to each of the plurality of cylinders 10 of the internal combustion engine and one end of each independent intake pipe. And an intake air amount restricting means (throttle valve 1) disposed in the collective portion. The intake air amount estimating means including the throttle valve 1 and the throttle control unit 7B includes an intake air amount control unit. An intake air amount estimation model (collector throttle system model in FIG. 24) modeling the intake passage from the upstream side of the means (throttle valve 1) to the cylinder in consideration of the volume change.

Thus, when the intake air amount at the time of completion of intake valve closing of the control target cylinder is predicted and estimated prior to the crank angle by the time when fuel injection of the control target cylinder is started, the intake valve is estimated from the intake air amount estimation start timing. In particular, it is possible to predict and estimate the throttle flow area until the completion of closing, and to take into account changes in the throttle flow area from the intake air amount estimation start timing to the completion of intake valve closing. Highly accurate fuel injection control can be realized during the transient operation of the engine.
That is, in the collective throttle system shown in FIG. 23, as in the first and second embodiments, highly accurate fuel injection control is performed using the estimated intake air amount for fuel control to the control target cylinder. be able to.

Further, as various sensors for detecting the operating state of the internal combustion engine, an atmospheric pressure sensor 15 and a temperature sensor 16 for detecting atmospheric pressure are provided in the intake passage upstream of the throttle valve 1, and the intake air amount control means The upstream pressure is corrected based on the atmospheric pressure detected by the atmospheric pressure sensor, and the intake air temperature is corrected based on the detection signal of the temperature sensor 16.
In this way, by correcting the atmospheric pressure and the intake air temperature at regular intervals based on the sensor detection values, it is possible to estimate the intake air amount for fuel control with higher accuracy.

  The correction process for the atmospheric pressure and the intake air temperature is the same as in the third embodiment described above by providing the atmospheric pressure sensor 15 and the temperature sensor 16 on the upstream side of the throttle valve 1 in the first and second embodiments. It can be applied by incorporating correction control.

  In the first to third embodiments (FIGS. 1, 21, and 23), as the intake air amount control means, the throttle actuator 6 and the throttle valve 1 that are driven under the control of the throttle control units 7, 7A, and 7B. The case where the electronic throttle made of the above is used has been described, but it goes without saying that the present invention can be similarly applied to the case where a normal wire-driven mechanical throttle valve is used.

It is explanatory drawing which shows the relationship between the throttle opening used in the case of the intake air amount estimation estimation control by the 1st intake air amount estimation means in Embodiment 1 of this invention, and an actual throttle opening. It is explanatory drawing which shows the relationship between the actual throttle downstream pressure, estimated downstream pressure, and estimated estimated downstream pressure in Embodiment 1 of this invention. 1 is a configuration diagram schematically showing an entire system of an internal combustion engine control apparatus according to Embodiment 1 of the present invention. FIG. It is explanatory drawing which shows the time change characteristic of the estimated estimated throttle opening estimated by the throttle opening predictive estimation control in Embodiment 1 of this invention. It is explanatory drawing which shows the intake valve closing model in Embodiment 1 of this invention. It is explanatory drawing which shows the intake valve opening model in Embodiment 1 of this invention. It is a flowchart which shows a part of 1st intake air amount estimation flow in Embodiment 1 of this invention. It is a flowchart which shows a part of 1st intake air amount estimation flow in Embodiment 1 of this invention. It is a flowchart which shows a part of 1st intake air amount estimation flow in Embodiment 1 of this invention. It is a flowchart which shows a part of 1st intake air amount estimation flow in Embodiment 1 of this invention. It is a flowchart which shows a part of 1st intake air amount estimation flow in Embodiment 1 of this invention. It is a flowchart which shows a part of 1st intake air amount estimation flow in Embodiment 1 of this invention. It is a flowchart which shows a part of 1st intake air amount estimation flow in Embodiment 1 of this invention. It is a flowchart which shows a part of 1st intake air amount estimation flow in Embodiment 1 of this invention. It is a flowchart which shows a part of 1st intake air amount estimation flow in Embodiment 1 of this invention. It is explanatory drawing which shows the valve timing map of the intake valve in Embodiment 1 of this invention. It is explanatory drawing which shows the area term map in Embodiment 1 of this invention. It is explanatory drawing which shows the speed term map in Embodiment 1 of this invention. It is explanatory drawing which shows the cylinder volume map in Embodiment 1 of this invention. It is explanatory drawing which shows the predetermined time A map in Embodiment 1 of this invention. It is a block diagram which shows roughly the whole system of the internal combustion engine control apparatus which concerns on Embodiment 2 of this invention. It is a flowchart which shows the 2nd intake air amount estimation flow in Embodiment 2 of this invention. It is a block diagram which shows schematically the whole system of the internal combustion engine control apparatus which concerns on Embodiment 3 of this invention. It is explanatory drawing which shows the gathering part throttle system model in Embodiment 3 of this invention. It is a flowchart which shows a part of 3rd intake air amount estimation flow in Embodiment 3 of this invention. It is a flowchart which shows a part of 3rd intake air amount estimation flow in Embodiment 3 of this invention. It is a flowchart which shows a part of 3rd intake air amount estimation flow in Embodiment 3 of this invention. It is a flowchart which shows a part of 3rd intake air amount estimation flow in Embodiment 3 of this invention. It is a flowchart which shows a part of 3rd intake air amount estimation flow in Embodiment 3 of this invention. It is a flowchart which shows a part of 3rd intake air amount estimation flow in Embodiment 3 of this invention. It is a flowchart which shows a part of 3rd intake air amount estimation flow in Embodiment 3 of this invention. It is a flowchart which shows a part of 3rd intake air amount estimation flow in Embodiment 3 of this invention. It is explanatory drawing which shows the valve timing map and predetermined time A map of an intake valve in Embodiment 3 of this invention. It is explanatory drawing which shows the speed term map in Embodiment 3 of this invention. It is explanatory drawing which shows the relationship between the fuel injection start timing in the conventional 4-cylinder engine, and the intake air amount referred at the time of injection control with the stroke table of each cylinder. It is explanatory drawing which shows the relationship between the actual intake air amount at the time of the transient operation only by the conventional apparatus and the 1st intake air amount estimation means, and the intake air amount used for fuel amount calculation with a characteristic curve.

Explanation of symbols

  1 throttle valve, 2 fuel injection valve, 3 intake valve, 5 crank angle sensor, 6 throttle actuator, 7, 7A, 7B throttle control unit, 8, 8B engine control unit, 9 throttle downstream side, 10 cylinder, 12 crankshaft, 14 pressure sensors, 15 atmospheric pressure sensors, 16 temperature sensors.

Claims (17)

Intake air amount control means for controlling the intake air amount to the internal combustion engine by controlling the flow path area;
Channel area calculating means for calculating the channel area of the intake air amount control means;
Downstream pressure detection means for detecting the pressure on the downstream side of the intake air amount control means;
A rotational speed detection means for detecting the rotational speed of the internal combustion engine;
An intake air amount estimating means for estimating an intake air amount sucked into a cylinder of the internal combustion engine,
The flow path area calculating means includes
Channel area detecting means for detecting the channel area;
Between the intake air amount estimation start timing at which the intake air amount estimation means starts the intake air amount estimation process and the intake valve closing completion point of the control target cylinder of the internal combustion engine. And a channel area predicting means for predicting and estimating the channel area,
The intake air amount estimation means includes
Using the upstream and downstream pressures of the intake air amount control means, the flow path area, the rotational speed of the internal combustion engine, the intake air temperature of the internal combustion engine, and the cylinder volume of the internal combustion engine And
Predicting and estimating the intake air amount until the intake valve closing completion time from the intake air amount estimation start timing to an injection start timing at which fuel injection to the control target cylinder is started An internal combustion engine control device.   The flow passage area estimation means uses the intake air amount estimation start timing and the intake air amount estimation start timing using the flow passage area detected at a predetermined time before the intake air amount estimation start timing. The internal combustion engine control device according to claim 1, wherein the flow passage area of the intake air amount control means until the intake valve closing completion time is estimated and estimated.   The flow path area predicted and estimated by the flow path area estimation means is fixedly set to the predetermined value over a period from when the predetermined value is reached to when the intake valve is closed. The internal combustion engine control device according to claim 1 or 2.   4. The intake air amount control means controls the flow channel area to a target value and sets the target value of the flow channel area at the intake air amount estimation start timing to the predetermined value. The internal combustion engine control device described.   The intake air amount estimation means calculates the intake air amount sucked into the cylinder between the intake air amount estimation start timing and the intake valve closing completion time, and the in-cylinder pressure at the intake valve closing completion time. The internal combustion engine control apparatus according to any one of claims 1 to 4, wherein the estimation is performed based on: The intake air amount estimating means includes a predicted estimated downstream pressure setting means,
The predicted estimated downstream pressure setting means sets the predicted estimated downstream pressure at the completion time of the intake valve closing estimated prior to the crank angle of the internal combustion engine as the in-cylinder pressure at the completion time of the intake valve closing. The internal combustion engine control device according to any one of claims 1 to 5, wherein The predicted estimated downstream pressure setting means includes
The previous estimated estimated downstream pressure, the pressure upstream of the intake air amount control means, the flow path area, the cylinder volume of the internal combustion engine, the rotational speed of the internal combustion engine, and the intake air of the internal combustion engine Based on the temperature and the estimated estimated downstream pressure after a predetermined period from the previous time,
The internal combustion engine control according to claim 6, wherein the estimated estimated downstream pressure at the completion time of the intake valve closing is estimated by repeatedly executing the estimated estimated downstream pressure estimation process after a predetermined period from the previous time. apparatus. The downstream pressure estimation start time for starting the estimation process of the predicted estimated downstream pressure is set to a predetermined time before the injection start time,
The internal combustion engine control according to claim 7, wherein the predetermined time is shifted in a direction in which the downstream pressure estimation start time is advanced with respect to the injection start time as the rotational speed of the internal combustion engine increases. apparatus. A plurality of intake valves corresponding to each of a plurality of cylinders of the internal combustion engine;
A plurality of independent intake pipes each having one end communicating with each intake valve;
A collecting portion communicated with one end of each independent intake pipe;
An intake air amount limiting means disposed in each of the independent intake pipes,
The intake air amount estimation means has two intake air amount estimation models,
The two intake air amount estimation models are:
An intake valve closing model that models an intake passage from the upstream side of the intake air amount control means to each intake valve;
9. An intake valve opening model that models an intake passage from the upstream side of the intake air amount control means to the cylinder in consideration of a volume change. The internal combustion engine control device according to item. A plurality of independent intake pipes corresponding to each of the plurality of cylinders of the internal combustion engine;
A collecting portion communicated with one end of each independent intake pipe;
An intake air amount limiting means disposed in the collecting portion;
2. The intake air amount estimation unit includes an intake air amount estimation model that models an intake passage from an upstream side of the intake air amount control unit to the cylinder in consideration of a volume change. The internal combustion engine control apparatus according to any one of claims 8 to 9.   The downstream pressure detecting means includes a previously estimated pressure on the downstream side of the intake air amount control means, a pressure on the upstream side of the intake air amount control means, the flow path area, and an in-cylinder volume of the internal combustion engine. 11. The downstream pressure of the intake air amount control means at this time is estimated based on the rotational speed of the internal combustion engine and the intake air temperature of the internal combustion engine. The internal combustion engine control device according to any one of the above.   12. The internal combustion engine control according to claim 11, wherein the downstream pressure detecting means estimates the downstream pressure of the intake air amount control means this time at predetermined intervals according to a crank angle of the internal combustion engine. apparatus. The downstream pressure detection means includes a pressure sensor disposed on the downstream side of the intake air amount control means,
11. The internal combustion engine control device according to claim 1, wherein the pressure on the downstream side of the intake air amount control means is detected based on a detection signal of the pressure sensor. . The intake air amount control means includes a throttle valve,
The flow path area calculation means including the flow path area detection means and the flow path area prediction means calculates the flow path area based on an opening of the throttle valve. 14. The internal combustion engine control device according to any one of up to 13.   The rotational speed detection means includes a crank angle sensor that detects a crank angle of the internal combustion engine, detects the rotational speed of the internal combustion engine, and detects the in-cylinder volume set based on the crank angle. The internal combustion engine control apparatus according to any one of claims 1 to 14, wherein It has an atmospheric pressure sensor that detects atmospheric pressure,
The pressure on the upstream side of the intake air amount control means is corrected based on an atmospheric pressure detected by the atmospheric pressure sensor, according to any one of claims 1 to 15. Internal combustion engine control device. A temperature sensor disposed in the intake passage of the internal combustion engine;
The internal combustion engine control device according to any one of claims 1 to 16, wherein the intake air temperature is corrected based on a detection signal of the temperature sensor.

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