JPH10205369A - Device and method for controlling throttle of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control turbulence of A/F(the air-fuel ratio) in relation to the steep and complicated accelerating operation. SOLUTION: In an ECU(electronic control unit) 20, intake air pressure as load of an internal combustion engine 1 is estimated according to the mean acceleration opening in which the change of the acceleration opening AP detected by an accelerator opening sensor 9 is smoothed, the throttle opening of a throttle valve 3 is controlled on the basis of the estimated intake air pressure, and the air amount is supplied to the internal combustion engine 1. The fuel amount proportional to the estimated intake air pressure is calculated, the fuel injection time of an injector 17 is controlled, and the fuel amount is supplied to the internal combustion engine 1. Therefore, since the suitable air amount and fuel amount are supplied to the internal combustion engine 1, turbulence of A/F can be restrained even if the accelerating operation is the steep and complicate behavior.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throttle control device for an internal combustion engine which controls a degree of opening of a throttle valve by driving a motor in accordance with an accelerator operation amount and the like, and a control method thereof.

[0002]

2. Description of the Related Art Conventionally, there has been known a throttle control device for an internal combustion engine called an "electronic throttle system" which controls a degree of opening of a throttle valve by driving a motor in accordance with an accelerator operation amount or the like. In such a throttle control device, for example, a current is supplied to a motor in accordance with a signal from an accelerator opening sensor that detects an accelerator opening corresponding to the amount of depression of an accelerator pedal, and the throttle valve is driven by driving the motor. Are opened and closed to control the amount of air supplied to the internal combustion engine. At this time, proportional / integral / differential control (PID control) is performed on the motor so that the deviation between the signal from the throttle opening sensor for detecting the throttle opening of the throttle valve and the signal from the accelerator opening sensor is eliminated.
Is performed.

[0003] As a prior art document related to this, there is known one disclosed in Japanese Patent Publication No. 7-33781. In this apparatus, a fuel amount based on an accelerator opening based on an accelerator operation amount or the like is calculated, and an air amount that provides a predetermined A / F (air-fuel ratio) with respect to the fuel amount is obtained by opening and closing a throttle valve. The technology is shown.

[0004]

Here, in the above, the fuel amount obtained from the accelerator operation amount is calculated by estimating that there is a future execution condition on the extension of the current execution condition. By the way, when the accelerator operation has a sudden and complicated behavior, a deviation occurs between the fuel amount at the time of calculation and the required fuel amount at the time of execution, and the A / F greatly fluctuates from the stoichiometric air-fuel ratio. There was a problem that it caused the deterioration of.

Accordingly, the present invention has been made to solve such a problem, and supplies an appropriate amount of air and a corresponding amount of fuel to an internal combustion engine even when the accelerator operation is steep and complicated. Accordingly, it is an object of the present invention to provide a throttle control device for an internal combustion engine and a control method thereof, which can suppress A / F disturbance.

[0006]

According to the throttle control device for an internal combustion engine of the first aspect, the change in the accelerator opening is smoothed, and the load on the internal combustion engine, for example, based on the smoothed accelerator opening, for example, The intake pressure and the intake air amount are estimated. The amount of fuel supplied to the internal combustion engine is calculated based on the estimated load, and the target throttle opening is controlled so as to achieve the estimated load. Therefore, when a complicated accelerator operation is performed, for example, when acceleration is performed by stepping on the accelerator a plurality of times, the change in load becomes complicated, but in the present invention, the change in the accelerator opening is smoothed. Is done. Then, the fuel injection amount is calculated based on the load estimated based on the smoothed accelerator opening,
The target throttle opening is calculated so that the actual load becomes the estimated load. Thereby, it is possible to suppress disturbance of A / F (air-fuel ratio) when a complicated accelerator operation is performed.

According to a second aspect of the present invention, the smoothness of the accelerator opening is set according to the warm-up state of the internal combustion engine. Thereby, claim 1
In addition to the effect described above, the stall of the internal combustion engine during acceleration can be prevented even when a heavy fuel having low volatility is used. In general, heavy fuel has low volatility, so that when the temperature of the internal combustion engine is low (during warm-up), the A / F (air-fuel ratio) tends to be lean. When such a heavy fuel is used in a system set with a normal fuel, when a steep acceleration is performed, the tendency becomes strong, and the internal combustion engine may stall. Therefore, the degree of smoothness of the accelerator opening is set in accordance with the warm-up state of the internal combustion engine.Specifically, the degree of smoothness is increased as the temperature of the internal combustion engine is low and the volatility of heavy fuel or the like is low, Avoid sudden acceleration. More specifically, the accelerator opening is smoothed with a certain time constant, and the time constant is made larger as the temperature of the internal combustion engine becomes lower. Here, as the parameter indicating the warm-up state of the internal combustion engine, it is preferable to use the cooling water temperature, the oil temperature, and the elapsed time after the start of the internal combustion engine (the number of ignitions, the number of fuel injections, the elapsed time, and the like).

According to a third aspect of the present invention, when the change in the accelerator opening is larger than a predetermined amount, or when the change in the accelerator opening becomes equal to or less than the predetermined amount, the throttle opening is controlled within a predetermined period. Changes are smoothed. As described above, the present invention may be used only when the accelerator opening degree at which the effect of the present invention is large changes greatly, or when the accelerator opening degree is not stable.

According to a fourth aspect of the present invention, a delay time generated when injecting a fuel amount is calculated, a load estimated based on the delay time is corrected, and a load is estimated based on the corrected load. Thus, the target throttle opening is calculated. As a result, the A / F (air-fuel ratio) can be controlled with higher accuracy.

[0010] According to the throttle control apparatus for an internal combustion engine of the present invention, the change in the accelerator opening detected by the accelerator opening detecting means is smoothed, and the load on the internal combustion engine is determined based on the smoothed accelerator opening. For example, the intake pressure and the intake air amount are estimated. The amount of fuel supplied from the injector to the internal combustion engine is calculated based on the estimated load, and the target throttle opening of the throttle valve is controlled so as to achieve the estimated load. Therefore, when a complicated accelerator operation is performed, for example, when acceleration is performed by stepping on the accelerator a plurality of times, the change in load becomes complicated, but in the present invention, the change in the accelerator opening is smoothed. Is done.
Then, the fuel injection amount is calculated based on the load estimated based on the smoothed accelerator opening, and the target throttle opening is calculated such that the actual load becomes the estimated load. Thereby, it is possible to suppress disturbance of A / F (air-fuel ratio) when a complicated accelerator operation is performed.

According to the throttle control method for an internal combustion engine of the present invention, the fuel amount calculation step is executed before the throttle opening degree control step. The target throttle opening can be calculated based on the load estimated in the load estimating step based on the accelerator opening in which the change in the accelerator opening is smoothed in the opening change smoothing step.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples.

FIG. 1 is a schematic diagram showing the overall configuration of a throttle control device for an internal combustion engine and a method for controlling the same according to an embodiment of the present invention.

In FIG. 1, an internal combustion engine 1 has an intake passage 2
The air is supplied through. The throttle valve 3 is provided in the middle of the intake passage 2 and has a DC
The motor (throttle valve driving means) 4 is opened and closed to regulate the flow rate of air passing through the throttle valve 3.
The throttle valve 3 is provided with a throttle opening sensor 5 for detecting a throttle opening. The accelerator pedal 8 is provided with an accelerator opening sensor (accelerator opening detecting means) 9 for detecting the accelerator opening. Also,
The crankshaft 10 of the internal combustion engine 1 has a rotation angle sensor 11 for detecting an engine rotation speed from a transition state of the rotation angle.
Are arranged. The intake passage 2 of the internal combustion engine 1 is provided with an intake pressure sensor 12 for detecting an intake pressure corresponding to the amount of air passing through the passage, and the exhaust passage 13 of the internal combustion engine 1 is provided with an oxygen concentration in the passage. Is provided. Further, the internal combustion engine 1 is provided with a water temperature sensor 15 for detecting a cooling water temperature and an intake temperature sensor 16 for detecting the temperature of intake air taken into the intake passage 2 on the upstream side of the throttle valve 3 in the intake passage 2. ing. Reference numeral 17 denotes an injector (fuel injection valve) for supplying fuel into the intake passage 2 of the internal combustion engine 1, and reference numeral 18 denotes an internal combustion engine 1
An IN (intake) valve for opening and closing an intake port to the combustion chamber of the engine 1 is an EX (exhaust) valve for opening and closing an exhaust port from the combustion chamber of the internal combustion engine 1.

An ECU (Electronic Control Unit) 20 has a throttle opening TA signal from the throttle opening sensor 5, an accelerator opening AP signal from the accelerator opening sensor 9, and an engine rotation from the rotation angle sensor 11. The speed NE signal, the intake pressure PM signal from the intake pressure sensor 12, the oxygen concentration Ox signal from the oxygen concentration sensor 14, the cooling water temperature THW signal from the water temperature sensor 15, and the intake temperature THA signal from the intake temperature sensor 16 are input. I have.

Next, an electrical configuration in the ECU 20 will be described with reference to FIG.

In FIG. 2, an ECU 20 includes a CPU 21 as a well-known central processing unit, a ROM 22 storing a control program, a RAM 23 storing various data, a throttle opening degree TA signal from the throttle opening degree sensor 5, an accelerator opening degree sensor. 9, the intake pressure PM signal from the intake pressure sensor 12, the oxygen concentration sensor 1
4, the cooling water temperature THW signal from the water temperature sensor 15, and the intake air temperature THA from the intake air temperature sensor 16.
A / A that converts each analog signal into a digital signal
A D conversion circuit 24, a waveform shaping circuit 25 for shaping the waveform of the engine speed NE signal from the rotation angle sensor 11, a throttle valve target opening TAEX and a fuel injection time TAU, which will be described later, calculated by the CPU 21 based on these various information. An output circuit 26 supplies a current ITAEX for driving the DC motor 4 of the valve 3 and a current ITAU for driving the injector 17.

FIG. 3 is a flowchart showing a base routine in the CPU 21 of the ECU 20 used in the internal combustion engine throttle control apparatus and the control method according to one embodiment of the present invention. It is explained based on.

In FIG. 3, first, at the same time as the power is turned on by turning on an ignition switch (not shown) (when the power is turned on), initialization is executed in step S100. In this initialization, for example, a variable storage area such as the RAM 23 is set to an initial value, and input signals from various sensors are checked. After the initialization in step S100, the full-scale control process in the following loop is repeatedly executed.

In step S200, the accelerator opening A is used as an accelerator opening averaging process (opening change smoothing means).
By averaging P, an averaged accelerator opening AP 'is calculated, which facilitates control, especially calculation of the injection amount. Next, step S3
00, the estimated intake pressure PMSYM is calculated as an intake pressure estimation process (load estimation means) before the throttle valve 3 is operated using the averaged accelerator opening AP ', the engine speed NE, and the like as parameters. You. Next, the process proceeds to step S400, and a fuel amount corresponding to the estimated intake pressure PMSYM and other parameters is calculated as a fuel system calculation process (fuel amount calculation means). Next, step S50
0, and as intake pressure timing calculation processing, λ =
The timing of the intake pressure corresponding to 1 (reference) fuel amount is calculated. Next, at step S600, as a throttle valve target opening calculation process (throttle opening control means), the throttle opening of the throttle valve 3 is calculated backward based on the estimated intake pressure subjected to timing correction, and the optimum throttle valve is set. The target opening TAEX is calculated, and thereafter, steps S200 to S600 are repeatedly executed.

Next, each of the above routines will be described in detail.

First, a description will be given with reference to a time chart of FIG. 5 based on a flowchart of FIG. 4 showing a processing procedure of the accelerator opening averaging in step S200 of FIG. The subroutine for averaging the accelerator opening is 8
It is executed by the CPU 21 every ms.

In FIG. 4, first, an accelerator pedal opening AP is read in step S201. Next, step S202
Then, it is determined whether the accelerator opening change amount ΔAP exceeds a predetermined value α (see FIG. 5). Step S20
When the determination condition 2 is satisfied and the accelerator opening change amount ΔAP exceeds the predetermined value α, the process proceeds to step S203, and the steady state counter CCLR of the accelerator opening AP is cleared to “0”. Next, the process proceeds to step S204, where an averaging process is performed on the accelerator opening AP. The averaging method includes a transfer function 1 / (1 + T
Using S), the time constant T is set from the map shown in FIG. 20 based on the warm-up state of the internal combustion engine 1. A calculation process of the generalized accelerator opening AP 'is executed. The warm-up state of the internal combustion engine 1 is the cooling water temperature,
It may be detected from the oil temperature or the like, or may be obtained from the elapsed time after the engine is started (the number of times of ignition, the number of times of fuel injection, the elapsed time, etc.). Here, the averaged accelerator opening AP 'obtained by averaging the accelerator opening AP is stored in the averaged accelerator opening AP' storage area of the RAM 23 in the ECU 20, and the subroutine ends.

As described above, by setting the time constant T according to the warm-up state of the internal combustion engine 1, when heavy fuel is used in the system for normal fuel, the internal combustion generated when the internal combustion engine 1 is at low temperature is used. Stall of the engine 1 can be prevented. In other words, heavy fuel has low volatility with respect to normal fuel,
When the internal combustion engine 1 is at a low temperature, the A / F (air-fuel ratio) becomes lean, but this tendency increases when rapid acceleration is performed. Therefore, when averaging the accelerator opening when the internal combustion engine 1 is at a low temperature, the time constant T is increased to suppress sudden acceleration and prevent the internal combustion engine 1 from stalling even when heavy fuel is used. Like that.

On the other hand, if the determination condition of step S202 is not satisfied and the accelerator opening change amount ΔAP is equal to or smaller than the predetermined value α, the control of the throttle opening, fuel injection, etc. is performed so that the accelerator opening AP needs to be averaged. Since it can be determined that the operation is not an accelerator operation that makes it difficult, the process proceeds to step S205, and the steady state determination counter CCLR is incremented by "1". Next, the process proceeds to step S206, and it is determined whether the steady state determination counter CCLR exceeds a predetermined value β (see FIG. 5). The determination condition of step S206 is satisfied,
When the steady state determination counter CCLR exceeds the predetermined value β, it is determined that the accelerator opening AP is in a stable state, and the process proceeds to step S207, where “1” is added to the predetermined value β to make the steady state determination counter CCLR. After the processing is performed, the process proceeds to step S208, and the accelerator opening AP that is not averaged is stored in the RAM in the ECU 20 as it is.
23 are stored in the averaged accelerator opening AP 'storage area,
This subroutine ends. If the determination condition in step S206 is not satisfied and the steady-state determination counter CCLR is equal to or smaller than the predetermined value β, the process proceeds to step S204.
After the averaging process for the accelerator opening AP is performed, the present subroutine ends.

Next, a description will be given with reference to a subroutine in FIG. 7 based on a flowchart in FIG. 6 showing a processing procedure of the intake pressure estimation in step S300 in FIG. The intake pressure estimated here is an intake pressure with respect to the smoothed accelerator opening, that is, an intake pressure when the throttle valve 3 is controlled based on the smoothed accelerator opening. The intake pressure estimation subroutine is executed every 8 ms by the CPU.
This is executed at 21. Here, to estimate the intake pressure PM,
A method using the equation of state of gas will be described as an example.

In FIG. 6, first, at step S301
The accelerator opening A is an averaged accelerator opening AP.
Parameters such as P ', the engine speed NE, and the intake air temperature THA are read. Next, the process proceeds to step S302, where a surge tank passing air amount Gin calculation process is executed. In the surge tank passing air amount Gin calculation process, first, in step S311 in the subroutine of FIG. 7, the throttle valve passing air amount Ginα [kg / sec] is calculated by the following equation (1).

[0028]

(Equation 1)

Here, PA: atmospheric pressure [Pa], S: flow sectional area [m ² ], κ: specific heat ratio, R: gas constant [J / (k)
g · K)], T: intake air temperature [K].

Then, the flow shifts to step S312, where the air amount C2 [kg / kg] leaks to the throttle valve passing air amount Ginα.
sec] is added and the surge tank passing air amount Gin [k
g / sec], the process returns to the subroutine of FIG. 6, and in step S303, the in-cylinder inflow air amount Gou
t [kg / sec] is calculated by the following equation (2).

[0031]

(Equation 2)

Here, NE: engine speed [rpm],
PE: exhaust pressure = atmospheric pressure [Pa, N / m ² ], ε: compression ratio, κ: specific heat ratio, C3: Vc / (2 × 60 × R × T),
Vc: The total displacement [m ³ ].

Next, the flow shifts to step S304, where the air amount Gin passing through the surge tank and the air amount Gout flowing into the cylinder are set.
And the intake pressure change amount ΔPM (differential value of the intake pressure PM) is calculated by the following equation (3).

[0034]

ΔPM = dPM / dt = ｛(Gin−Gout) / V｝ κRT (3) where PM: intake pressure [Pa, N / m ² ], t: time [sec], Gin : Air flow through surge tank [kg / s
ec], Gout: Inflow air amount into cylinder [kg / sec]
c], V: surge tank volume [m ³ ], κ: specific heat ratio,
R: gas constant [J / (kg · K), Nm / (kg ·
K)], T: Intake air temperature [K].

Next, in step S305, the intake pressure change amount ΔPM is integrated (every minute time Δt), the estimated intake pressure PMSYM (see the time chart shown in FIG. 19) is calculated, and this subroutine is terminated. .

Next, returning to FIG. 3, in step S400,
Fuel system calculation processing is executed. First, A / F (air-fuel ratio)
A characteristic diagram showing an output voltage with respect to an air-fuel ratio of the oxygen concentration sensor 14 in FIG. 9, a map in FIG. 10, and a time chart in FIG. 11 based on a flowchart in FIG. 8 showing a processing procedure of a fuel injection time TAU calculation required in the control. This will be described with reference to FIG. Note that this fuel injection time calculation subroutine is executed by the CPU 21 every 8 ms.

In the A / F control, a basic fuel injection time TAU is calculated based on the engine speed NE and the intake pressure PM, correction based on water temperature, temperature, etc., which affects the combustion state, and exhaust gas after combustion, Feedback control based on the oxygen concentration in the passage 13 is performed. Note that the feedback control is executed in order to correct variations due to individual differences of the internal combustion engine 1, aging, and the like. In this embodiment,
First, it is determined whether feedback control by the oxygen concentration sensor 14 in the exhaust passage 13 is possible. That is, since the oxygen concentration sensor 14 is activated at a certain temperature or higher, the detection result of the oxygen concentration Ox signal of the oxygen concentration sensor 14 cannot be used for A / F control immediately after the internal combustion engine 1 is started. . This oxygen concentration sensor 1
4 is an activation flag XAC to indicate whether
T is used, and the activation flag XACT is set to “0” by initialization, and is set to “1” when activated.

In FIG. 8, first, at step S401
It is determined whether the activation flag XACT of the oxygen concentration sensor 14 disposed in the exhaust passage 13 is "0".
If the oxygen concentration sensor 14 has not been activated yet and the determination condition of step S401 is satisfied, step S40 is performed.
Then, it is determined whether the oxygen concentration Ox signal from the oxygen concentration sensor 14 is 0.5 V or more. Here, approximately 0 V is output from the oxygen concentration sensor 14 as an oxygen concentration Ox signal until activation, and after activation, as shown in FIG. 9, the excess air ratio λ is less than a predetermined reference value. Is determined (rich determination [less than λ = 1]), approximately 1.0 V is output, and if it is determined that it is equal to or more than a predetermined reference value (lean determination [λ = 1 or more]), approximately 0 V is output. Is output. Here, λ = 1 is the stoichiometric air-fuel ratio. Therefore, during the low temperature starting state, the A / F (air-fuel ratio) is controlled to be rich, so that the activation of the oxygen concentration sensor 14 is determined by the O.D. signal whose oxygen concentration Ox signal is the activation determination value. 5
It can be performed depending on whether or not the voltage is V or more.

When the determination condition in step S402 is satisfied, the flow shifts to step S403, where the oxygen concentration Ox signal is set to O.D. The activation counter CA for measuring the stabilization time is not necessarily stable even if the voltage is 5 V or more.
CT is incremented by "+1". Next, step S
The process proceeds to 404, where it is determined whether the activation counter CACT is equal to or greater than a set value KACT corresponding to the stabilization time. When the determination condition of step S404 is satisfied,
Assuming that the oxygen concentration sensor 14 has been activated, the process proceeds to step S405, and the activation flag XACT is set to "1". In step S401, the oxygen concentration sensor 1
4 is already activated, the activation flag XA
CT is 1, and steps S402 to S405 are skipped.

Next, in step S406, even if the oxygen concentration sensor 14 is activated, feedback control cannot be performed by itself. As another execution condition of the feedback control, in the present embodiment, it is determined whether the cooling water temperature THW detected by the water temperature sensor 15 disposed in the internal combustion engine 1 is equal to or higher than 20 ° C. When the determination condition of step S406 is satisfied, the process proceeds to step S407, and the feedback permission flag XFB is set to “1”. On the other hand, the determination condition of step S402 is not satisfied,
Alternatively, if the determination condition in step S404 is not satisfied, the activation flag XA is determined in step S408 for the purpose of confirmation.
CT is set to “0”. After step S408 or when the determination condition of step S406 is not satisfied, the process proceeds to step S409, and the feedback permission flag XFB is set to “0”.

Step S407 or step S409
After the feedback permission flag XFB is set in step S410, the estimated intake pressure PM calculated from the engine speed NE in step S410 and the averaged accelerator opening AP 'in step S411.
SYM is read. Next, the routine proceeds to step S412, where the basic fuel injection time T, which has been obtained in advance by experiment using the map shown in FIG. 10 so that λ = 1, is set in advance by using the engine speed NE and the estimated intake pressure PMSYM as parameters.
P is calculated. Next, the process proceeds to step S413, where a cooling water temperature correction coefficient FTHW is calculated based on the cooling water temperature THW, and an intake air temperature correction coefficient FTHA is calculated based on the intake air temperature THA. Next, the process proceeds to step S414, in which the coolant temperature correction coefficient FTHW and the intake temperature correction coefficient F are added to the basic fuel injection time TP.
The fuel injection time TAU is multiplied by THA or the like. Note that these correction coefficients use the optimum values obtained by experiments, but may be obtained by using a map or a predetermined calculation formula. Next, the process proceeds to step S415, where it is determined whether the feedback permission flag XFB is “1”. When the execution condition of the feedback control is satisfied, the determination condition of step S415 is satisfied, and the determination condition of step S416 is satisfied.
Move to In step S416, step S414
Is multiplied by the feedback correction value (air-fuel ratio correction coefficient) FAF to obtain the final fuel injection time TAU, and this subroutine is terminated. On the other hand, when the determination condition in step S415 is not satisfied, the fuel injection time TAU calculated in step S414
Is set as the final fuel injection time TAU, and this subroutine ends.

Here, the calculation procedure of the above-described feedback correction value FAF will be described with reference to the time chart of FIG. Basically, while referring to the oxygen concentration Ox signal in the exhaust passage 13, for example, when the A / F (air-fuel ratio) is lean, the fuel injection time TAU is increased. The control is repeated such that the injection amount is started to decrease and the fuel injection amount is started to increase when the fuel is reversed from the rich side to the lean side again.

More specifically, in order to generate a feedback correction value FAF based on 1.0 as a value, first, based on whether the oxygen concentration Ox signal from the oxygen concentration sensor 14 is on the rich side of 0.5 V or more. A flag XOx is created, and a delay value TDL1 is provided on the rising side from the inversion point of the flag XOx, and a delay value TDL2 is provided on the falling side to operate the flag XOxM. Based on the flag XOxM, a predetermined integral value INT1 is added on the lean side to increase the feedback correction value FAF, and a predetermined integral value INT2 is added on the rich side to reduce the feedback correction value FAF. In order to improve the response and prevent the A / F (air-fuel ratio) from vibrating, when the flag XOxM is inverted to the rising side, the feedback correction value FAF is added to the skip value SKP1 and the feedback correction value FAF is skipped to the smaller side. To flag XOx M
Is inverted to the falling side, the skip value SKP2 is added and skipped to the larger side.

These delay values TDL1, TDL2,
Integration values INT1, INT2 and skip values SKP1, S
KP2 is a suitable value easily obtained by an experiment so as to eliminate the above-mentioned variation factors due to the individual difference of the internal combustion engine 1, the aging, and the like. On the other hand, when the feedback control is not permitted, as described with reference to FIG. 8, the fuel injection time TA calculated in step S414
U is used as it is as the final fuel injection time TAU. As described above, using the fuel injection time TAU in which the feedback correction value FAF is not integrated means that the open loop control is executed.

Next, the drive control of the injector 17 will be described with reference to the map of FIG.
This will be described with reference to the timing charts of FIGS.

The injection start timing and the injection end timing are set for the injector 17, and during the period, the fuel injection is instructed to the injector 17. In the fuel injection, it is necessary to determine the injection end timing in advance corresponding to the combustion cycle of the internal combustion engine 1, and the injection start timing is set retroactively from the injection end timing.

In FIG. 12, the engine speed NE is determined in step S421, and the estimated intake pressure PMSY is determined in step S422.
After M is read, the process proceeds to step S423, and the valve closing time PINJCL of the injector 17 is calculated (see FIG. 13). Next, the routine proceeds to step S424, where the fuel injection time TAU is added to the valve closing time PINJCL to make the valve opening time PINJOP. As shown in FIG. 14, 180 ° CA which is a signal interval of the reference signal T180 for each cylinder.
(Crank angle) expressed in time using T180, T1
The time obtained by subtracting the valve opening time PINJOP from 80 is set as the valve opening timing TOP.

Next, the flow shifts to step S425, where it is determined whether the basic timing of the injector 17 in any one of the cylinders is reached. When the determination condition in step S425 is not satisfied, the present subroutine is terminated. On the other hand, if it is the basic timing of any one of the cylinders, step S425
Are satisfied, and the injector 17 corresponding to the cylinder is selected as shown in FIG. 15 showing the reference signal for each cylinder and the driving sequence of the injector 17 corresponding to the reference signal. Signal T
The valve opening time PINJOP is subtracted from 180, and the valve opening timing TOP is calculated. Next, in step S427, a valve opening timer for driving the injector 17 to open is set, and in step S428, a valve closing timer for driving the injector 17 to close is set, and the present subroutine ends. In this way, the fuel corresponding to the fuel injection time TAU from the valve opening timing TOP is injected into the intake passage 2 of the internal combustion engine 1 from the injector 17 by the time interruption.

Next, returning to FIG. 3, in step S500,
Intake pressure timing calculation processing (estimated load correction means) is executed. A description will be given with reference to the time chart of FIG. 17 based on the flowchart of FIG. 16 showing the processing procedure of the intake pressure timing calculation. The subroutine of the intake pressure timing calculation is executed by the CPU 21 every 8 ms.

In FIG. 16, the fuel injection time TAU is read in step S501. Next, the routine proceeds to step S502, where a required time TBASE from the closing of the injector 17 to the closing of the IN (intake) valve 18 is calculated. Here, the fuel injection timing control of this subroutine is controlled by the valve closing timing of the injector 17 (refer to the valve closing time PINJCL of the injector 17 calculated by the map of FIG. 13 in step S423 of FIG. 12). The required time TBASE is obtained from the phase difference in the closing time of the IN valve 18 determined by the target closing time of the injector 17 and the cam profile of the internal combustion engine 1 (see FIG. 17). Next, the flow shifts to step S503, where the other required time (valve closing delay time, etc.) FTIME is calculated. After that, the flow shifts to step S504, where the filling amount of the air-fuel mixture in the cylinder is determined from the fuel injection calculation time. The delay time TDLY until the time when the IN valve 18 is closed, which is the time point, is calculated by adding the required time TBASE and the required time FTIME to the fuel injection time TAU, and this subroutine is terminated. Here, the target intake pressure P
The value obtained by correcting the M value by the delay time TDLY from the intake pressure PM value used in the fuel system calculation is the intake pressure PM value suitable for fuel injection.

Next, returning to FIG. 3, in step S600,
The throttle valve target opening calculation processing (throttle opening control means including estimated load correction means) is executed. A description will be given based on the flowchart of FIG. 18 showing the processing procedure of the throttle valve target opening calculation with reference to the time chart of FIG. The throttle valve target opening calculation subroutine is executed by the CPU 21 every 8 ms. FIG. 19A shows the averaged accelerator opening AP ′ with respect to the accelerator opening AP and the estimated intake pressure PMSYM with respect to the intake pressure PM when the throttle control is executed.
19 (b) and 19 (c) show details between time t1 and time t2 shown in FIG. 19 (a). FIG. 19B shows a state of occurrence of a conventional intake pressure reading error, and FIG. 19C shows a state of conformity of the estimated intake pressure before and after averaging the accelerator opening. . Note that time t1 indicates the time when the fuel injection time TAU calculation is completed, and time t2 indicates the time when the IN valve is closed.

In FIG. 18, the accelerator opening AP is read in step S601. Next, the process proceeds to step S602, where it is determined whether the accelerator opening change amount ΔAP exceeds a predetermined value α. When the determination condition of step S602 is satisfied and the accelerator opening change amount ΔAP exceeds the predetermined value α, the process proceeds to step S603, and the estimated intake pressure P calculated in step S300 in the base routine of FIG.
An estimated intake pressure PMSYM2 corrected by MSYM by a delay time TDLY is calculated (FIG. 19C).
reference). On the other hand, when the determination condition of step S602 is not satisfied and the accelerator opening change amount ΔAP is equal to or smaller than the predetermined value α, the process proceeds to step S604, and the estimated intake pressure PMS calculated in step S300 in the base routine of FIG.
YM is directly used as the estimated intake pressure PMSYM2, and the intake pressure timing correction is not performed.

Step S603 or step S604
Then, the process proceeds to step S605, in which the estimated intake pressure PMSYM is calculated in the reverse manner using the calculated state equation of the gas so as to become the estimated intake pressure PMSYM2, that is, the estimated intake pressure PMSYM2 → passing through the surge tank. The throttle valve target opening TAEX is calculated by the procedure of air amount Gin → throttle valve passing air amount Ginα → flow cross-sectional area S → throttle valve target opening TAEX, and this subroutine ends. The DC motor 4 of the throttle valve 3 is driven by the output circuit 26 under feedback control based on the throttle opening degree TA signal from the throttle opening degree sensor 5 so that the throttle opening target opening degree TAEX is achieved.

As described above, the throttle control device for an internal combustion engine according to the present embodiment functions as an opening change smoothing means when the accelerator opening changes like the accelerator opening AP in FIG. The averaged accelerator opening AP 'is calculated by the accelerator opening averaging process in step S200 of step S3. Further, the intake pressure when the throttle opening is controlled based on the averaged accelerator opening AP 'is estimated by the intake pressure estimating process of step S300 in FIG. 3 which functions as load estimating means. Then, the estimated intake pressure PMSY is calculated by the throttle valve target opening calculation process in step S600 in FIG. 3 which functions as a throttle opening control means.
The target throttle opening TAEX is calculated to be M, and the throttle opening is controlled. Therefore, in the fuel system calculation process in step S400 in FIG. 3 that functions as the fuel amount calculation unit, the fuel injection amount TAU may be calculated based on the estimated intake pressure PMSYM as shown in FIG. . Therefore, even with a complicated accelerator operation as shown in FIG. 19, there is no reading error of the intake pressure as shown in FIG. 19B, that is, A / F (air-fuel ratio).
The fuel injection control can be performed without disturbance. It is preferable that the target opening calculation process of the throttle valve 3 is performed after the fuel system calculation process. In other words, by performing the fuel system arithmetic processing first, step S500 in FIG.
, And a delay time (delay time) when the fuel amount calculated in the fuel system calculation process is supplied from the injector 17 to the internal combustion engine 1.
The estimated intake pressure PMSYM is corrected in consideration of TDLY, and the target throttle opening TAEX of the throttle valve 3 can be calculated based on the corrected intake pressure PMSYM2 in the throttle valve target opening calculation processing in step S600. As a result, A / F (air-fuel ratio) can be more accurately performed.
Can be controlled. In this embodiment, only the throttle valve opening is controlled.
In a system provided with a C (Idle Speed Control) valve, this may be used in combination to control the estimated intake pressure to be obtained.

In the above embodiment, the DC motor 4 is used as an actuator for opening and closing the throttle valve 3. However, the present invention is not limited to this. Can also be used.

Further, in the above embodiment, the intake pressure is estimated from the accelerator opening. However, in a system having an air flow meter and obtaining the fuel injection amount based on the intake air amount and the engine speed, the accelerator opening is May be used to estimate the intake air amount. Also in this case, similarly to the present embodiment, the fuel amount is calculated based on the estimated intake air amount, and the target throttle opening is calculated based on the corrected estimated intake air amount in consideration of fuel supply delay and the like. What should I do?

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing the overall configuration of a throttle control device for an internal combustion engine and a throttle control device in a control method thereof according to an example of an embodiment of the present invention.

FIG. 2 is a block diagram showing an electric configuration inside an ECU in a throttle control device for an internal combustion engine and a control method therefor according to an example of an embodiment of the present invention.

FIG. 3 is a flowchart showing a processing procedure of a base routine in a CPU in an ECU used in a throttle control device for an internal combustion engine and a control method thereof according to one embodiment of the present invention.

FIG. 4 is a flowchart showing a processing procedure of accelerator opening averaging in FIG. 3;

FIG. 5 is a time chart in the accelerator opening degree averaging process of FIG. 4;

FIG. 6 is a flowchart showing a processing procedure of intake pressure estimation in FIG.

FIG. 7 is a flowchart showing a processing procedure for calculating the amount of air passing through the surge tank in FIG. 6;

FIG. 8 is a flowchart showing a processing procedure of fuel system calculation in FIG.

FIG. 9 is a characteristic diagram showing an output voltage with respect to an air-fuel ratio of an oxygen concentration sensor used in a throttle control device for an internal combustion engine and a control method thereof according to one embodiment of the present invention.

FIG. 10 is a map for calculating a basic fuel injection time in FIG. 8;

FIG. 11 is a time chart showing a procedure for calculating a feedback correction value in FIG. 8;

FIG. 12 is a flowchart showing a processing procedure of drive control of an injector used in a throttle control device for an internal combustion engine and a control method thereof according to one embodiment of the present invention.

FIG. 13 is a map for calculating the valve closing time of the injector in FIG.

FIG. 14 is a timing chart showing an injector drive signal with respect to a reference signal for each cylinder in a throttle control device and a control method for an internal combustion engine according to one example of an embodiment of the present invention.

FIG. 15 is a timing chart showing drive control of an injector with respect to a reference signal for each cylinder in a throttle control device for an internal combustion engine and a control method therefor according to one embodiment of the present invention.

FIG. 16 is a flowchart showing a processing procedure of an intake pressure timing calculation in FIG. 3;

FIG. 17 is a time chart for explaining the time required from the closing of the injector to the closing of the IN valve in FIG. 16;

FIG. 18 is a flowchart showing a processing procedure of a throttle valve target opening calculation in FIG.

FIG. 19 is a time chart showing an outline of control in a throttle control device for an internal combustion engine and a control method thereof according to one example of an embodiment of the present invention.

FIG. 20 is a map for calculating a time constant in the accelerator opening degree averaging process of FIG. 4 from a cooling water temperature.

[Explanation of symbols]

 Reference Signs List 1 internal combustion engine 2 intake passage 3 throttle valve 4 DC motor 5 throttle opening sensor 8 accelerator pedal 9 accelerator opening sensor 11 rotation angle sensor 12 intake pressure sensor 13 exhaust passage 14 oxygen concentration sensor 17 injector 20 ECU (electronic control device)

Claims (6)

[Claims] 1. An opening change smoothing means for smoothing a change in an accelerator opening, and a load estimating means for estimating a load on an internal combustion engine based on the accelerator opening smoothed by the opening change smoothing means. A fuel amount calculating means for calculating an amount of fuel supplied to the internal combustion engine based on the load estimated by the load estimating means; and a target throttle opening which is a load estimated by the load estimating means. And a throttle opening control means for outputting a control signal. 2. The throttle control device for an internal combustion engine according to claim 1, wherein the opening degree change smoothing means sets a degree of smoothing according to a warm-up state of the internal combustion engine. 3. The opening change smoothing means, when the change in the accelerator opening is larger than a predetermined amount, or within a predetermined period after the change in the accelerator opening becomes a predetermined amount or less. 3. The throttle control device for an internal combustion engine according to claim 1, wherein the throttle control device smoothes the throttle valve. 4. The throttle opening control means calculates a delay time generated when injecting the fuel amount calculated by the fuel amount calculation means, and is estimated by the load estimating means based on the delay time. 4. The vehicle according to claim 1, further comprising: an estimated load correction unit configured to correct a load, wherein the target throttle opening is calculated based on the load corrected by the estimated load correction unit. 5. A throttle control device for an internal combustion engine according to claim 1. 5. A throttle valve for adjusting a flow rate of air taken into the internal combustion engine, a throttle valve driving means for driving the throttle valve, an injector for supplying fuel to the internal combustion engine, and an accelerator for detecting an accelerator opening degree Opening degree detecting means; opening degree change smoothing means for smoothing a change in the accelerator opening degree detected by the accelerator opening degree detecting means; and an accelerator opening degree smoothed by the opening degree change smoothing means. Load estimating means for estimating the load of the internal combustion engine, and fuel amount calculating means for calculating an amount of fuel supplied to the internal combustion engine from the injector based on the load estimated by the load estimating means; Means for calculating a target throttle opening of the throttle valve, which is a load estimated by the means, and outputting a control signal. Throttle control apparatus for an internal combustion engine, characterized by comprising a time control means. 6. An opening change smoothing step for smoothing a change in the accelerator opening, and a load estimating step for estimating a load on the internal combustion engine based on the accelerator opening smoothed in the opening change smoothing step. Calculating a fuel amount supplied to the internal combustion engine based on the load estimated in the load estimating step; calculating a target throttle opening which is a load estimated in the load estimating step; A throttle opening control step of outputting a control signal, wherein the fuel amount calculating step is executed before the throttle opening control step.