JPH07119515A - Fuel supply amount control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To properly maintain a fuel amount at all times by correcting a parameter every moment according to engine condition when an amount of fuel supplied into an internal combustion engine is controlled, in compliance with a fuel behavior model using a parameter for displaying the behavior of fuel in the intake system of the internal combustion engine. CONSTITUTION:A parameter for displaying the behavior of fuel is stored in a map M4 on the basis of operating condition detected by a means M2. A required fuel amount is calculated by a means M5 on the basis of operating condition and the target value of an air-fuel ratio detected by a means M3. Furthermore, the fuel injection amount of a fuel injection valve M1 is calculated by a means M6 on the basis of a parameter which is read out from the map M4 according to the required fuel amount and operating condition. Meanwhile the fuel injection amount and operating condition are memorized by means M7, M8 respectively, and a real fuel amount is calculated by a means M9 on the basis of the past operating condition and the detected air-fuel ratio, and also the real fuel amount is memorized by a means M10. The parameter is corrected by a means M11 on the basis of a calculated real fuel amount, the past real fuel amount, and fuel injection amount.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine for controlling the amount of fuel injected and supplied to the internal combustion engine according to a fuel behavior model using parameters (adhesion rate, evaporation rate) representing the behavior of the fuel in the internal combustion engine. The present invention relates to a fuel supply amount control device for an engine.

[0002]

2. Description of the Related Art Conventionally, a control device of this type, that is, a control device for controlling the amount of fuel supplied to an internal combustion engine based on the behavior of the fuel in the intake system is disclosed in, for example, Japanese Unexamined Patent Application Publication No. Hei 1 (1999) -163.
Device disclosed in Japanese Patent Laid-Open No. 1-26042, JP-A-1-267
A device described in Japanese Patent Application Laid-Open No. 332, a device disclosed in Japanese Patent Application Laid-Open No. 1-267333, a device described in Japanese Patent Application Laid-Open No. 1-271642, and the like are known. All of these control devices determine the amount of fuel required for the internal combustion engine based on the operating conditions of the internal combustion engine and the target value of its air-fuel ratio, and the amount of fuel adhered to the intake pipe wall surface of the internal combustion engine and its According to the fuel behavior model in which the behavior of the fuel flowing into the cylinder of the internal combustion engine is mathematically expressed using the evaporation amount as a parameter, the fuel amount to be actually supplied is calculated from the obtained required fuel amount.

[0003]

As described above, in the above conventional control device, the fuel is injected and supplied to the internal combustion engine in accordance with the fuel behavior model using the parameter representing the behavior of the fuel flowing into the cylinder of the internal combustion engine. Since the amount of fuel to be controlled is controlled, if the parameters are properly set, the controlled fuel supply amount will surely bring the air-fuel ratio of the internal combustion engine close to its ideal value. It becomes a proper thing that can. However, as a matter of fact, since those parameters are fixedly determined in advance based on certain operating conditions of the internal combustion engine, for example, the property of the fuel supplied to the fuel tank is assumed to be the standard in the internal combustion engine. If they are different, or if the internal combustion engine itself changes with time, these parameters cannot naturally correspond to the fuel behavior model, and the above-mentioned controlled fuel supply amount is also appropriate. Cannot be.

Incidentally, in recent years, for example, Japanese Unexamined Patent Publication No. 4-2528.
As seen in the device described in Japanese Patent No. 33, 33, a control device provided with means for dynamically correcting the above parameters so as to be able to dynamically respond to differences in fuel properties, changes in the internal combustion engine over time, and the like. Is also proposed. However, the control device
A lot of data is used to correct those parameters, and the parameters are statistically modified by the hill climbing method from those data. Although the parameters can be dynamically modified, the responsiveness Is still
Leave a problem.

The present invention has been made in view of such circumstances, and in controlling the amount of fuel to be injected and supplied to the internal combustion engine according to a fuel behavior model using a parameter representing the behavior of the fuel in the internal combustion engine, A fuel supply amount control apparatus for an internal combustion engine, which can dynamically correct those parameters according to the respective conditions of the internal combustion engine and with good responsiveness to always maintain an appropriate fuel supply amount to the internal combustion engine. The purpose is to provide.

[0006]

In order to achieve these objects, in the present invention, as shown in the claim correspondence diagram in FIG. 11, a fuel injection valve M for controlling the amount of fuel injection into the internal combustion engine.
1, an operating condition detecting means M2 for detecting one or a plurality of elements indicating operating conditions of the internal combustion engine, and an air-fuel ratio detecting means M3 for detecting an air-fuel ratio of the internal combustion engine based on exhaust gas of the internal combustion engine. A parameter map M4 in which parameters representing the behavior of the fuel in the intake system of the internal combustion engine are mapped corresponding to the detected operating conditions, and based on the detected operating conditions and the target value of the air-fuel ratio Based on the required fuel amount calculation means M5 for calculating the fuel amount required for the internal combustion engine and the calculated required fuel amount and the parameters read from the parameter map corresponding to the detected operating conditions, A fuel injection amount calculation means M6 for calculating a fuel injection amount which is an operation amount of the fuel injection valve M1 according to a fuel behavior model using parameters.
A fuel injection amount storage means M7 for temporarily storing the calculated fuel injection amount, an operating condition storage means M8 for temporarily storing the detected operating condition, and the temporarily stored past operating condition. An actual fuel amount calculation means M9 for calculating the amount of fuel actually supplied to the internal combustion engine based on the detected air-fuel ratio, and an actual fuel amount storage means M10 for temporarily storing the calculated actual fuel amount. , The parameter map based on the calculated actual fuel amount, the past actual fuel amount stored in the actual fuel amount storage means M10, and the past fuel injection amount stored in the fuel injection amount storage means M7. And a parameter correction means M11 for correcting parameters mapped to M4 in real time.

[0007]

The above-mentioned fuel injection valve M1, operating condition detecting means M2,
The internal combustion engine is controlled according to the fuel supply amount control method executed by the parameter map M4, the required fuel amount calculation means M5, and the fuel injection amount calculation means M6, that is, the fuel behavior model using the parameters representing the behavior of the fuel in the internal combustion engine. The method itself for controlling the amount of fuel injected and supplied to the engine is basically
There is no difference from the above-described conventional fuel supply amount control by the control device.

Here, as described above, the parameters mapped in the parameter map M4 are dynamically modified by the parameter modifying means M11. And here,
This correction is made by correcting the past fuel injection amount (the fuel amount injected and supplied through the fuel injection valve M1 in the past) which is primarily stored in the fuel injection amount storage means M7 and the actual fuel amount calculation means M.
9 is a current actual fuel amount calculated through 9 (for example, a value obtained by multiplying the reciprocal of the current air-fuel ratio detected by the air-fuel ratio detecting means M3 by the past operating condition stored in the operating condition storing means M8). ) And the past value of the actual fuel amount stored in the actual fuel amount storage means M10.

Incidentally, the past fuel injection amount and the present and past actual fuel amounts are, for example, when an autoregressive model of degree 1 is adopted in a system for controlling the fuel amount and an appropriate dead time is set for this. Is a known value.
Then, a parameter indicating the behavior of the fuel is introduced as an unknown number at that time. Therefore, if the past fuel injection amount, which is a known value, and the present and past actual fuel amounts are used and the parameters are obtained by, for example, the successive least squares method, the obtained parameters are also determined by the internal combustion engine. It is calculated in real time as the most suitable fuel behavior variable according to the state at that time. Then, the parameter map M4 is
The corresponding portions are overwritten and corrected by the parameters thus calculated.

Therefore, even if the amount of fuel to be injected and supplied to the internal combustion engine is controlled according to the fuel behavior model using the above parameters, the control is performed quickly and accurately according to the state of the internal combustion engine at that time. The updated latest parameters will be used, and the controlled fuel supply amount will be maintained properly.

Further, the past fuel injection amount and the present and past actual fuel amounts used for the calculation of the above parameters are each set to one value in accordance with the control (the number of times of control) at that time. The specified data is itself suitable for use in the above-mentioned real-time parameter calculation and correction. Therefore, if the parameters are corrected by the above-mentioned configuration, it is not necessary to use the above-mentioned statistical method for obtaining the parameters to be corrected, and it is not necessary to store much data for that. .

The operating conditions detected by the operating condition detecting means M2 include the air pressure of the air drawn into the internal combustion engine, the rotational speed of the internal combustion engine, the temperature of the internal combustion engine, and the like. The parameters that are mapped in the parameter map M4 in accordance with the detected operating conditions include the attachment rate of fuel adhering to the wall surface of the intake system of the internal combustion engine and the evaporation rate of the fuel.

Further, when the air pressure and the rotational speed are detected as the operating conditions, it is easy to obtain the amount of air taken into the internal combustion engine based on the detected air pressure and the air-fuel ratio, as in the above example. When the actual fuel amount is calculated as a value obtained by multiplying the reciprocal of the current air-fuel ratio detected through the means M3 by the past operating condition stored in the operating condition storage means M8, the actual fuel amount is stored in the operating condition storage means M8. It is desirable to adopt this required air amount also as the operating condition to be temporarily stored.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a schematic configuration of an internal combustion engine (engine) mounted on a vehicle and its electronic control unit as an embodiment of a fuel supply amount control device according to the present invention.

First, the construction of an engine to be controlled and its electronic control unit in this embodiment will be described with reference to FIG. For example, in an engine 1 assuming a 4-cylinder 4-cycle spark point type, its intake air passes from an air cleaner 2 through an intake pipe 3, a surge tank 4, an intake manifold, as shown in FIG. It is inhaled into each cylinder via 5. On the other hand, fuel is pressure-fed from a fuel tank (not shown), and is fed from a fuel injection valve 6 provided in the intake manifold 5 to the engine 1
Injected toward each intake port of. The gas burned in the cylinder of the engine 1 is introduced into the catalytic converter 8 through the exhaust pipe 7, where harmful components (CO, HC, NOx) in the burned gas are cleaned by the three-way catalyst and discharged. .

The air sucked into the intake pipe 3 is
The flow rate is controlled by the throttle valve 9 which works in conjunction with the accelerator pedal. The opening of the throttle valve 9 is detected by the throttle opening sensor 10. The pipe pressure Pm of the intake pipe 3 is detected by the intake pressure sensor 11 provided in the surge tank 4.

The engine speed Ne of the engine 1 is
This is detected by a rotation speed sensor (crank angle sensor) 12 arranged near the crank shaft of the. The rotation speed sensor 12 is provided so as to face a ring gear that rotates in synchronization with the crankshaft of the engine 1. Here, for example, 24 pulse signals are output every two rotations (720 degrees) of the engine 1. It shall be.

The temperature TW of the cooling water filled in the water jacket provided around the body of the engine 1
Is detected by the water temperature sensor 13. A thermistor is usually used as the water temperature sensor 13, and a change in the water temperature TW is detected as a change in the resistance value of the thermistor.

In the exhaust pipe 7, a catalytic converter 8 is also provided.
An air-fuel ratio sensor 14 that detects the actual unburned oxygen concentration of the exhaust gas in that portion and outputs this as an air-fuel ratio detection signal A / F is disposed in the upstream portion of the. Incidentally, in this case, the air-fuel ratio detection signal A / F output from the air-fuel ratio sensor 14 takes a linear value with respect to the actual air-fuel ratio of the air-fuel mixture supplied to the engine 1.

On the other hand, the electronic control unit 20 includes a well-known central processing unit (CPU) 21, read only memory (ROM) 22, random access memory (RAM) 23 and backup RAM 24.
It is configured as an arithmetic and logic operation circuit centered on etc. The arithmetic logic operation circuit is provided with a signal input from each sensor,
An input / output port (I / O port) 25 for outputting a control signal to each actuator is connected to each other via a bus. Then, in the electronic control unit 20, the throttle opening, the intake pipe internal pressure Pm, the rotation speed Ne, the cooling water temperature TW, the air-fuel ratio A /
Processing such as inputting sensor signals such as F and the like, calculating a fuel injection amount TAU based on these sensor signals, and controlling the drive of the fuel injection valve 6 based on the calculated fuel injection amount TAU Is executed via the same input / output port 24.

2 to 6 show the electronic control unit 20 of
The configuration of the fuel supply amount control device according to this embodiment is shown functionally and concretely. The configuration of the fuel supply amount control device and the configuration of the fuel supply amount control device will be described below with reference to FIGS. 2 to 6. Its function will be described in more detail.

In the device of this embodiment, the parameters representing the behavior of the fuel in the intake system of the engine 1 are: the adherence rate x of the fuel adhering to the wall surface of the intake manifold 5, and the wall surface of the intake manifold 5. Of the adhered fuel, two parameters such as the ratio of the fuel sucked into the cylinder in the next control cycle, that is, the evaporation rate 1 / τ are used, and the engine 1 is operated according to the fuel behavior model using these parameters. Controls the amount of fuel injected and supplied. Then, here, as such a fuel behavior model, a model as shown in FIG. 2 is set. Incidentally, the fuel behavior model shown in FIG.
It is derived as follows.

That is, C.I. F. According to Aquino's formula,
The amount of fuel adhering to the intake manifold 5 is Mf (i),

[0024]

[Equation 1]

The amount of fuel given to the cylinder of the engine 1 as Gfc (i) is

[0026]

[Equation 2]

Is given as In these equations, i
Is a variable indicating the number of times of control from the start of the first sampling. Here, the transfer function is obtained as follows, where Gf is the input and Gfc is the output.

First, the equation (1) is transformed into a discrete system (Z transformation).
Then, the following equation (3) is obtained.

[0029]

[Equation 3]

Similarly, the equation (2) is converted into a discrete system (Z transformation) to obtain the following equation (4).

[0031]

[Equation 4]

Therefore, from these equations (3) and (4),

[0033]

[Equation 5]

And the transfer function obtained here is

[0035]

[Equation 6]

It becomes The transfer function thus obtained is
It is used in the behavior model shown in FIG. Figure 3
Based on the fuel behavior model set in this way, is detected by the intake pipe internal pressure (that is, intake pressure) Pm detected by the intake pressure sensor 11, the engine speed Ne detected by the rotation speed sensor 12, and the water temperature sensor 13. The fuel injection valve 6 based on the cooling water temperature TW and the air-fuel ratio A / F detected by the air-fuel ratio sensor 14.
2 shows an example of a functional and specific configuration of the electronic control unit 20 that determines the operation amount of.

That is, in the electronic control unit 20 shown in FIG. 3, the evaporation rate 1 / τ base map (τBa
The se map) 201 is a map in which the values (1 / τ) corresponding to the engine speed Ne and the intake pressure Pm are registered for the evaporation rate 1 / τ of the above-mentioned two parameters, and the adhesion rate x base map (xBase map) 202
Is a map in which a value (x) corresponding to the engine speed Ne and the intake pressure Pm is registered for the adhesion rate x of the two parameters. All of these maps are constructed in the backup RAM 24 described above, and the contents thereof are as shown in FIG. 4 or FIG. 6, respectively.

Incidentally, the τBase map 201, as shown in FIG. 4, has operating regions [A], [B] of the engine 1, which are determined by the engine speed Ne and the intake pressure Pm.
For each of [C] and [D], the evaporation rate 1 / τ that increases gradually is registered, and the evaporation is registered in the operating region determined by the engine speed Ne and the intake pressure Pm at each time. The value of the rate 1 / τ is read from the τBase map 201.

The evaporation rate 1 / τ is a parameter that is greatly influenced by the temperature of the engine 1 (cooling water temperature TW), and normally, when the engine 1 is cold, more fuel is supplied to the engine 1. Since it is necessary to supply, the control device of this embodiment corrects the value of the read evaporation rate 1 / τ through the temperature correction table 211 based on the cooling water temperature TW detected by the water temperature sensor 13. I have to. FIG. 5 shows a setting example of the temperature correction table 211.

As shown in FIG. 5, in the temperature correction table 211, the water temperature TW = 80 at which most of the fuel evaporates.
When the water temperature TW is lower than 80 ° C., the temperature correction coefficient KTHW is set in such a manner that the water temperature TW is less than 80 ° C. and gradually increases as the water temperature TW decreases.
Then, in the τBase map 201, based on the value of the temperature correction coefficient KTHW read from the temperature correction table 211 according to the water temperature TW, the evaporation rate 1 read out is
The value of / τ is

[0041]

[Equation 7]

Is corrected as follows. Where (1 / τB)
Is the evaporation rate 1 / read from the same τBase map 201.
It is a value obtained by correcting the value τBase of τ based on the temperature correction coefficient KTHW.

On the other hand, the xBase map 202 is, as shown in FIG. 6, sequentially for each of the operating regions [a], [b], and [c] of the engine 1 determined by the engine speed Ne and the intake pressure Pm. The adhesion rate x with which the value becomes smaller is registered, and the engine speed Ne and the intake pressure Pm at each time are registered.
The value of the adhesion rate x registered in the operating area determined by

[0044]

[Equation 8]

As a result, it is read from the xBase map 202. Where xB is the same xBase map 2
It is the value of the adhesion rate xBase read from No. 02. Also,
In the electronic control unit 20 shown in FIG. 3, the air amount calculation unit 203 sets the intake air amount Ga as the operating condition of the engine 1 to the engine speed Ne and the intake pressure P.
Based on m and

[0046]

[Equation 9]

The required fuel amount calculation unit 204 makes a request in each state of the engine 1 based on the calculated value of the air amount Ga and the value of the target air-fuel ratio A / F. The fuel quantity G'fc

[0048]

[Equation 10]

Is a part which is calculated as. It should be noted that the arithmetic units 203 and 204 can be realized as a lookup table using the ROM 22.

In the electronic control unit 20, the fuel injection amount calculation unit 205 multiplies the calculated required fuel amount G'fc by the inverse transfer function of the fuel behavior model shown in FIG.

[0051]

[Equation 11]

As the fuel amount G to be supplied to the engine 1,
This is a part for calculating f. The values of the evaporation rate 1 / τ and the adhesion rate x in the multiplied transfer function are the values (1 / τB read from the above-mentioned τBase map 201, respectively.
), And the value xB read from the xBase map 202
Is used. The fuel amount Gf thus calculated is multiplied by a predetermined unit conversion coefficient k in the electronic control unit 20,

[0053]

[Equation 12]

Is converted into the operation amount (fuel injection amount) TAU of the fuel injection valve 6. This converted operation amount TAU
However, it is applied to the fuel injection valve 6 through the input / output port 25 of the electronic control unit 20 to control the drive thereof, as described above.

On the other hand, the electronic control unit 20 shown in FIG.
In the fuel injection amount storage unit 206, the fuel injection amount storage unit 206 calculates the calculated fuel amount Gf for a plurality of control times (to be exact, Gf (i-4)).
Up to a maximum of four times before), the air amount storage unit 207 stores the air amount Ga calculated by the previous air amount calculation unit 203 also for a plurality of control times (to be exact, Ga ( i-3) is a part to store up to 3 times before). The actual fuel amount calculation unit 208 also stores the air amount Ga (i) stored three times before in the air amount storage unit 207.
-3) and the respective air-fuel ratio A / F (i) detected by the air-fuel ratio sensor 14,

[0056]

[Equation 13]

In this mode, the fuel amount Gfc (i) actually supplied to the engine 1 is calculated.
The actual fuel amount storage unit 209 is a unit that stores the actual fuel amount Gfc (i) calculated in this way and reads it as Gfc (i-1) to the parameter correction unit 210 in the next control cycle. Note that each of these storage units 20
6, 207, and 209 are realized by the RAM 23.

The parameter correction unit 210 has the past fuel amount Gf (i) stored in the fuel injection amount storage unit 206.
-3) and Gf (i-4), the past actual fuel amount Gfc (i-1) stored in the actual fuel amount storage unit 209, and the current actual fuel calculated through the actual fuel amount calculation unit 208. This is a part for correcting each of the above-mentioned parameters registered in the τBase map 201 and the xBase map 202 in real time based on the amount Gfc (i). That is, the parameter correction unit 210 is designed in advance by the following method in order to estimate the evaporation rate 1 / τ and the adhesion rate x based on these fuel amounts. (1) Modeling (Identification) of Controlled Object In the apparatus of this embodiment, the system for controlling the fuel supply amount is set such that the delay p due to dead time is p = 3 in the autoregressive model of degree 1, and the above-mentioned Aquino equation Evaporation rate 1
/ Τ and the amount of fuel entering the cylinder of the engine 1 obtained from the adhesion rate x, that is, the actual amount of fuel is Gfc (i),

[0059]

[Equation 14]

It is approximated as follows. Here, Gf is
This is the fuel injection amount calculated by the fuel injection amount calculation unit 205. Also, here for convenience,

[0061]

[Equation 15]

By the way, regarding the model equation of the above equation (14),

[0063]

[Equation 16]

Shall be treated as (2) Real-time calculation of model constants a and b (adaptive identification) When the above equation (16) is separated into a known signal and an unknown signal, the following equation is obtained.

[0065]

[Equation 17]

Here, if the second term on the right side of the equation (17) is transferred to the left side and this is designated as Y (i) again,

[0067]

[Equation 18]

In other words, the above equation (17) becomes

[0069]

[Formula 19]

It becomes And here, the unknown value a
And b are obtained by the recursive least squares method. That is, Θ
Is a parameter vector and W is a measurement value vector,

[0071]

[Equation 20]

When saying

[0073]

[Equation 21]

Then, under the condition of i → ∞

[0075]

[Equation 22]

Is guaranteed. Therefore, the model constants a and b, which are unknowns, can be obtained by using the algorithm of the equation (21). Therefore, here again, the equation (21) is executed in real time, and the obtained value is used as the model constant obtained here for convenience. However, in this equation (21), Γ is

[0077]

[Equation 23]

And

[0079]

[Equation 24]

It is a 2 × 2 symmetric matrix with an initial value of
In this way, the parameter correction unit 2 for obtaining the model constants a and b
10 further executes the following processing in order to correct the above-mentioned parameters registered in the τBase map 201 and the xBase map 202.

First, the obtained model constants a and b
To the evaporation rate 1 / τ and the adhesion rate x. This includes
Based on the substitution in equation (15) above,

[0082]

[Equation 25]

Execute. By executing the equation (25), the currently estimated evaporation rate 1 / τ and the adhesion rate x can be obtained in real time. On the other hand, in the parameter correction unit 210, based on the engine speed Ne and the intake pressure Pm at each time described above, from the τBase map 201, the operating regions [A], [B], and [C] shown in FIG. ,
And evaporation rate 1 / τ in the corresponding region of [D]
Value τBase, and the xBase map 202 is searched for the value xBase of the adhesion rate x in any one of the operating regions [a], [b], and [c] shown in FIG. Evaporation rate 1 obtained from the search value and the above estimation
The ratio of the difference between / τ and the adhesion rate x is calculated.

That is, regarding the evaporation rate, considering the above-mentioned temperature correction coefficient KTHW,

[0085]

[Equation 26]

Then, KτB is obtained as the ratio of the difference, and the adhesion rate of the other is

[0087]

[Equation 27]

As a result, KxB is calculated as the ratio of the difference.
After that, the parameter correction unit 210 updates the parameters based on the obtained ratios KτB and KxB for all the above-mentioned operating regions of the τBase map 201 and the xBase map 202.

That is, for the τBase map 201, the value τBase of the evaporation rate 1 / τ in all operating regions
Each of this

[0090]

[Equation 28]

As the other xBase map 202, it is updated (corrected) as follows, and this is updated for each value xBase of the adhesion rate x in all the operating regions.

[0092]

[Equation 29]

It is updated (corrected) as. By such update (correction), these τBase map 201 and xBa
The se map 202 holds optimal parameters according to the state at that time as a system for controlling the fuel supply amount in the apparatus of the embodiment.

7 to 10 show the processing actually performed by the electronic control unit 20 to control the amount of fuel supplied to the engine 1, the evaporation rate 1 / τ base map (τBase map) 201 and the adhesion rate. x base map (xBase map)
A series of processing procedures for the processing for automatically correcting 202 are shown, and the operation of the control device of the embodiment will be described in further detail below with reference to FIGS. 7 to 10.

FIG. 7 shows the control system of this embodiment,
5 is a flowchart showing a fuel injection amount calculation routine executed by the electronic control unit 20 to control the fuel injection valve 6. The electronic control unit 20 executes the routine shown in FIG. 7 when calculating the fuel injection amount.

That is, the electronic control unit 20 firstly, via the input / output port 25, the engine speed Ne which is the detection output of the rotation speed sensor 12, and the intake pipe internal pressure (the intake pressure which is the detection output of the intake pressure sensor 11). ) Pm and the cooling water temperature TW which is the detection output of the water temperature sensor 13 are respectively taken in (step 100), and the above τBase map 201 and x are drawn.
From the Base map 202, the parameters in the operating region corresponding to the acquired information, that is, the evaporation rate (1 / τ
B) and the adhesion rate xB are respectively searched (step 11).
0). This search is for those τBase maps 201 and xBa
It is performed based on the latest version of the se map 202. In particular, when searching for the evaporation rate (1 / τB),
As described above, the temperature correction table 211 illustrated in FIG. 5 is referred to.

In this way, the electronic control unit 2 has retrieved the corresponding parameters of the evaporation rate (1 / τB) and the adhesion rate xB.
Next, 0 is requested based on the previous calculated air amount value Ga (i-1) and the target air-fuel ratio A / F value, which are obtained by the air amount calculation portion 203 and are stored in the air amount storage portion 207. The basic amount of fuel G'fc required this time is calculated by executing the above equation (10) through the fuel amount calculation unit 204.
(I) is calculated (step 120). Then, the electronic control unit 20 further determines the calculated required fuel amount G′fc.
The fuel injection amount calculation unit 20 calculates the equation (11) by multiplying (i) by the inverse transfer function of the fuel behavior model shown in FIG.
Fuel amount G to be supplied to the engine 1
f (i) is calculated (step 130). As described above, the evaporation rate (1 / τB) and the adhesion rate xB retrieved above are used as the values of the evaporation rate 1 / τ and the adhesion rate x in the multiplied transfer function, respectively.

This calculated fuel amount Gf (i) is then applied to the electronic control unit 2 as described above as the equation (12).
Within 0, a predetermined unit conversion coefficient k is multiplied and converted into an operation amount (fuel injection amount) TAU of the fuel injection valve 6 (step 140). The converted manipulated variable TAU is applied to the fuel injection valve 6 via the input / output port 25 of the electronic control unit 20 to control the driving thereof.

In this way, the electronic control unit 2 which calculates and outputs the operation amount (fuel injection amount) TAU in the control cycle.
0 thereafter updates the stored contents of the actual fuel amount storage unit 209, the fuel injection amount storage unit 206, and the air amount storage unit 207 described above.

That is, in the actual fuel amount storage unit 209, the actual fuel amount Gfc which is the storage element thereof is

[0101]

[Equation 30]

(Step 150), the fuel injection amount storage unit 206 stores the fuel injection amount Gf, which is its storage element.

[0103]

[Equation 31]

(Step 160), and the air amount storage unit 207 stores the air amount G which is its storage element.
a

[0105]

[Equation 32]

It is updated as (step 170). Figure 8
Is the electronic control unit 20 in the control system of the embodiment.
6 is a flowchart showing a processing procedure for automatic correction of the τBase map 201 and the xBase map 202, which is executed in parallel with the above-described fuel injection amount calculation routine or in another time zone. Electronic control unit 2
0 is used to correct the parameters registered in these maps 201 and 202, that is, the evaporation rate 1 / τ and the adhesion rate x, through the parameter correction unit 210 described above.
The correction routine shown in FIG. 8 is executed.

That is, the electronic control unit 20 first takes in the air-fuel ratio A / F which is the detection output of the air-fuel ratio sensor 14 via the input / output port 25 (step 200),
Moreover, the air amount Ga (i-3) three times before (three cycles before) is read from the air amount storage unit 207 (step 21).
0), the actual fuel amount calculation unit 208 executes the calculation of the above equation (13), and at that time, the fuel amount actually supplied to the cylinder of the engine 1, that is, the actual fuel amount Gfc (i).
Is calculated (step 220).

The electronic control unit 20 then outputs the engine speed Ne, which is the detection output of the rotation speed sensor 12, and the intake pipe internal pressure (intake pressure) Pm, which is the detection output of the intake pressure sensor 11, to the input / output port, as before. After fetching each via 25 (step 230), the substitution of the above equation (18) (step 240) and the substitution of the above equation (15) (step 2).
50, step 260), the calculation of the model constants a and b is started (step 270). The calculation routine of this model constant is shown in FIG.

That is, when calculating the model constant, the electronic control unit 20 first stores the value of the actual fuel amount Gfc (i-1) stored in the actual fuel amount storage unit 209 and the fuel injection amount storage unit 206. Stored fuel injection amount Gf
After reading the respective values of (i-3) and Gf (i-4), the measurement value vector and the parameter vector are defined as in the above equation (20) (step 271 and step 272),
2 × 2 shown in the equations (23) and (24)
Is introduced (step 273), and the symmetric matrix Γ of
Formula 1) is executed (step 274). Then, the model constants a and b obtained as a result are returned to the parameter correction routine shown in FIG.

The electronic control unit 20 that has obtained the model constants a and b in this way then uses the above-obtained model constants a and b in the parameter correction routine of FIG. And the attachment rate x (step 280), and based on the obtained evaporation rate 1 / τ and the attachment rate x, the base maps, ie, τBase map 201 and xBase map 202, are updated (step 290). ). A routine for updating these base maps is shown in FIG.

When updating these base maps, the electronic control unit 20 firstly takes in the engine speed N fetched as described above.
Based on e and the intake pressure Pm (step 230 in FIG. 8),
From the τBase map 201, the value τBase of the evaporation rate 1 / τ in the corresponding region of the operating region shown in FIG. 4, and from the xBase map 202 in the corresponding region of the operating region also shown in FIG. The value xBase of the adhesion rate x is searched for (step 291), and the ratios KτB and KxB of the differences between the searched values and the evaporation rate 1 / τ and the adhesion rate x obtained by the above estimation are respectively calculated in (26) above. It is obtained based on the equation and the equation (27) (step 292).

Then, the electronic control unit 20 thereafter sets τ
For all the above-mentioned operating regions of the Base map 201 and the xBase map 202, the parameters are updated by the calculated ratios KτB and KxB as in the above equations (28) and (29) (step 293). By such update (correction), these τBase maps 201 and x
As described above, the Base map 202 holds the optimum parameters according to the state at that time as a system for controlling the fuel supply amount in the apparatus of this embodiment.

As described above, according to the control device of this embodiment, the parameters (evaporation rate 1 / τ and adhesion rate) registered in the base maps (τBase map and xBase map) 201 and 202 through the parameter correction unit 210. x) is dynamically corrected according to, for example, the difference in the properties of the fuel to be refueled, the change with time of the engine 1, and the like. Moreover, in this embodiment, the correction of this parameter is performed through the past fuel injection amounts Gf (i-3), Gf (i-4) and the actual fuel amount calculation unit 208 which are temporarily stored in the fuel injection amount storage unit 206. Calculated current actual fuel amount Gfc
It is executed in real time based on (i) and the past value Gfc (i-1) of the actual fuel amount stored in the actual fuel amount storage unit 209.

Therefore, even if the fuel quantity to be injected and supplied to the engine 1 is controlled according to the fuel behavior model using the above parameters, the control is promptly and accurately corrected according to the state of the engine at that time. Also, the latest parameters will be used, and the controlled fuel supply amount will naturally be maintained at an appropriate level.

The values of the past fuel injection amount and the present and past actual fuel amounts used for the calculation of the above-mentioned parameters are all one value in accordance with the control (the number of times of control) at that time. The specified data is itself suitable for use in the above-mentioned real-time parameter calculation and correction. Therefore, if the parameters are corrected by the above configuration, it is not necessary to store a large amount of data in order to obtain the parameters to be corrected, and the above equations (30), (31), and (32) are used. It is sufficient to store a very small amount of limited data that can be updated through.

In the apparatus of this embodiment, if the model constants a and b (evaporation rate 1 / τ, adhesion rate x) at that time are obtained through the parameter correction routine (FIG. 8),
By this, the base map (τBase map, xBase map) is also updated, but in addition, for example, the change of the model constants a and b (evaporation rate 1 / τ, adhesion rate x) obtained above is monitored. Alternatively, the base map may be updated only when the variation amount is larger than a predetermined amount. That is, in this case, even if there is a difference in the properties of the fuel to be refueled or a change over time in the engine, such a difference is small as not to affect the control of the fuel supply amount. When, the update of the base map is suppressed.

[0117] In addition, in this parameter correction routine and the previous fuel injection amount calculation routine (Fig. 7), the timing of fetching various sensor data is arbitrary, and at any time before it is used. It may be.

Further, in the apparatus of the embodiment, the parameter correction routine and the fuel injection amount calculation routine are treated as separate routines that are executed in parallel or in different time zones. Two routines are 1
Of course, it is possible to treat them as one continuous routine.

Further, in the apparatus of the above-mentioned embodiment, an apparatus for controlling the supply of an appropriate fuel amount on the premise of the fuel behavior model using the evaporation rate 1 / τ and the adhesion rate x as parameters as shown in FIG. Although shown, the fuel behavior model presupposed in the fuel supply amount control device according to the present invention is
Of course, it is not necessarily limited to such a model. In addition, for example, the fuel supply amount control device can be applied to various fuel behavior models that are modeled also including the spray state of the fuel injection valve, the property of the fuel, etc. in a manner similar to the above. In addition, the same effect as described above can be expected. Further, in this case, the data to be taken in as the operating condition detection data is not limited to the engine speed Ne, the intake pressure Pm, and the cooling water temperature TW described above.

[0120]

As described above, according to the present invention, in controlling the amount of fuel to be injected and supplied to the internal combustion engine according to the fuel behavior model using the parameter representing the behavior of the fuel in the intake system of the internal combustion engine, The latest parameters, which are promptly and accurately modified according to the current state of the internal combustion engine, are used, and the controlled fuel supply amount is naturally maintained to be appropriate.

According to the present invention, the parameter to be corrected is calculated based on the past fuel injection amount and the current and past actual fuel amount. There is no need to use a conventional statistical method, nor is it necessary to store a large amount of data for that purpose.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of a fuel supply amount control device for an internal combustion engine according to the present invention.

FIG. 2 is a block diagram showing a fuel behavior model adopted in the control device of the embodiment.

FIG. 3 is a block diagram showing a functional and specific configuration example of the electronic control device of the control device of the embodiment.

FIG. 4 is a vaporization rate 1 / τ base map (τ
(Base map) is a graph showing a specific example thereof.

5 is a graph showing a specific example of the temperature correction table shown in FIG.

6 is a deposition rate x base map (xBase shown in FIG. 3;
3 is a graph showing a specific example of (map).

FIG. 7 is a flowchart showing a procedure for calculating a fuel injection amount by the control device of the embodiment.

FIG. 8 is a flowchart showing a procedure for correcting 1 / τ (evaporation rate) and x (adhesion rate) by the control device of the embodiment.

FIG. 9 is a flowchart showing a procedure for calculating a model constant by the control device of the embodiment.

FIG. 10 is a flowchart showing a base map update procedure by the control device of the embodiment.

FIG. 11 is a claim correspondence diagram.

[Explanation of symbols]

1 ... Engine, 2 ... Air cleaner, 3 ... Intake pipe, 4 ... Surge tank, 5 ... Intake manifold, 6 ... Fuel injection valve, 7 ... Exhaust pipe, 8 ... Catalytic converter, 9 ... Throttle valve, 10 ... Throttle opening sensor , 11 ... Intake pressure sensor, 12 ... Rotation speed sensor, 13 ... Water temperature sensor, 14
... air-fuel ratio sensor, 20 ... electronic control device, 21 ... CPU,
22 ... ROM, 23 ... RAM, 24 ... Backup RA
M, 25 ... Input / output port, 201 ... Evaporation rate 1 / τ base map (τBase map), 202 ... Adhesion rate x base map (xBase map), 203 ... Air amount calculation unit, 204 ...
Required fuel amount calculation unit 205 ... Fuel injection amount calculation unit 206
... Fuel injection amount storage unit, 207 ... Air amount storage unit, 208 ...
Actual fuel amount calculation unit, 209 ... Actual fuel amount storage unit, 210 ... Parameter correction unit, 211 ... Temperature correction table.

Claims (2)

[Claims] 1. A fuel injection valve for operating a fuel injection amount to an internal combustion engine, an operating condition detecting means for detecting one or more elements indicating operating conditions of the internal combustion engine, and an exhaust gas of the internal combustion engine. An air-fuel ratio detecting means for detecting the air-fuel ratio of the internal combustion engine, and a parameter map in which parameters representing the behavior of the fuel in the intake system of the internal combustion engine are mapped corresponding to the detected operating conditions, and the detected. Required fuel amount calculation means for calculating the fuel amount required for the internal combustion engine based on the operating condition and the target value of the air-fuel ratio, which corresponds to the calculated required fuel amount and the detected operating condition. Based on the parameters read from the parameter map according to the behavior model of the fuel using the parameters, the fuel for calculating the fuel injection amount, which is the operation amount of the fuel injection valve, is calculated. Injection amount calculation means, fuel injection amount storage means for temporarily storing the calculated fuel injection amount, operating condition storage means for temporarily storing the detected operating condition, and the temporarily stored past operation An actual fuel amount calculation means for calculating the amount of fuel actually supplied to the internal combustion engine based on the conditions and the detected air-fuel ratio; and an actual fuel amount storage means for temporarily storing the calculated actual fuel amount. A map to the parameter map based on the calculated actual fuel amount, the past actual fuel amount stored in the actual fuel amount storage means, and the past fuel injection amount stored in the fuel injection amount storage means. A fuel supply amount control device for an internal combustion engine, comprising: a parameter correction means for correcting a parameter being converted into a real time. 2. The detected operating conditions are the air pressure of the air taken into the internal combustion engine, the rotational speed of the internal combustion engine, and the temperature of the internal combustion engine. The parameters mapped in the parameter map are the adhesion rate of the fuel adhered to the wall surface of the intake system of the internal combustion engine and the evaporation rate of the fuel, and the operating conditions temporarily stored in the operating condition storage means are The fuel supply amount control device for an internal combustion engine according to claim 1, which is an air amount of the internal combustion engine that is calculated based on the detected air pressure of the intake air and the rotational speed.