JPH05118246A - Control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To accurately control the air-fuel ratio of a mixture supplied to an internal combustion engine provided with an exhaust gas recirculation system at a desired value. CONSTITUTION:An EGR direct rate EA (the rate of gas directly sucked into the combustion chamber out of the recirculation gas passed through a recirculation gas control valve (EGR valve) and an EGR carry-away rate EB (the rate of gas sucked into the combustion chamber out of the recirculation gas stagnated between the EGR valve and the combustion chamber) are calculated (S 41-S 51). The direct rate EA and the carry-away rate EB are calculated in response to the engine speed NE(tau) detected before a specified TDC(tau) and an engine load factor PBA(tau), using the maps set individually for the opening state (S42, SEcal=1) of the EGR valve, the time of shifting of the valve from the closed state to the opened state (S41, SEcal=O), the time of shifting of the valve from the opened state to the closed state (S43, SEcal=2). The circulation gas quantity (gin) actually sucked into the combustion chamber is calculated using the EA, EB, and a basic fuel quantity TIM is calculated based on the (gin).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an internal combustion engine having an exhaust gas recirculation mechanism, and more particularly to a control device for correcting a fuel supply amount and an ignition timing when exhaust gas recirculation is executed.

[0002]

2. Description of the Related Art In an internal combustion engine equipped with an exhaust gas recirculation mechanism, it has been known to correct the fuel supply amount when exhaust gas recirculation is executed. Also, considering that there is a delay in the operation response of the recirculation control valve disposed in the middle of the exhaust gas recirculation path,
There is also a control device that delays the start or end timing of the correction of the fuel supply amount from the time when the recirculation control valve is switched from the closed state to the open state or vice versa by the time corresponding to the engine operating state. Conventionally known (Japanese Patent Laid-Open No. 1-20
No. 3641).

[0003]

However, in the above conventional control device, when the recirculation control valve actually operates, the delay time until the recirculation gas that has passed through the control valve is actually sucked into the combustion chamber, Since the influence of the recirculation gas accumulated in the volume chamber provided in the middle of the recirculation path is not considered, there is room for improvement in accurately controlling the air-fuel ratio and the ignition timing of the air-fuel mixture supplied to the combustion chamber. It had been.

The present invention has been made in view of the above points, and appropriately controls the air-fuel ratio and the ignition timing in the transient state during the execution of exhaust gas recirculation and at the start or end of the recirculation of exhaust gas, and the exhaust gas characteristics and operation of the engine. It is an object of the present invention to provide a control device for an internal combustion engine that can further improve the performance.

[0005]

To achieve the above object, the present invention is a control device for an internal combustion engine having an exhaust gas recirculation mechanism including a recirculation gas control valve for controlling recirculation of exhaust gas to an intake system. , A fuel amount calculation means for calculating the amount of fuel to be supplied to the engine based on the engine speed and load condition, and a recirculation gas amount by controlling the recirculation gas control valve based on the operating condition of the engine. In a control device having a recirculation gas amount control means for controlling, a recirculation gas amount calculation means for calculating a recirculation gas amount based on the dynamic characteristics of the recirculation gas control valve and the recirculation gas, and the engine speed and load state of the engine. And a correction means for correcting the supplied fuel amount according to the recirculated gas amount.

Further, the present invention is a control device for an internal combustion engine having an exhaust gas recirculation mechanism including a recirculation gas control valve for controlling recirculation of exhaust gas to an intake system, wherein recirculation is performed based on an operating state of the engine. In a control device having a recirculation gas amount control means for controlling a recirculation gas amount by controlling a gas control valve, the recirculation gas amount control means is characterized in that the recirculation gas control valve and the recirculation gas dynamic characteristics and the rotation of the engine. The control amount of the recirculation gas control valve is calculated based on the number and the load state.

Further, the present invention is a control device for an internal combustion engine having an exhaust gas recirculation mechanism including a recirculation gas control valve for controlling the recirculation of exhaust gas to an intake system, wherein the engine speed and load state are controlled. A control device comprising: an ignition timing calculation means for calculating an ignition timing of the engine based on the engine; and a recirculation gas amount control means for controlling a recirculation gas amount by controlling a recirculation gas control valve based on an operating state of the engine. A recirculation gas control valve and a recirculation gas dynamic characteristic, a recirculation gas amount calculation means for calculating a recirculation gas amount based on the engine speed and a load state, and the ignition timing according to the recirculation gas amount. A correcting means for correcting is provided.

[0008]

The amount of recirculation gas is calculated on the basis of the dynamic characteristics of the recirculation gas control valve and the recirculation gas, the engine speed and the load condition, and the supplied fuel amount is corrected according to this amount of recirculation gas.

The control amount of the recirculation gas control valve is calculated on the basis of the dynamic characteristics of the recirculation gas control valve and the recirculation gas, the engine speed and the load state of the engine.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall configuration diagram of an internal combustion engine (hereinafter simply referred to as “engine”) equipped with an exhaust gas recirculation mechanism according to an embodiment of the present invention and a control system therefor. A throttle valve 3 is provided in the middle of the pipe 2. A throttle valve opening (θTH) sensor 4 is connected to the throttle valve 3 and outputs an electric signal according to the opening of the throttle valve 3 to output an electronic control unit for engine control (hereinafter referred to as “ECU”) 5
Supply to.

The fuel injection valve 6 is provided for each cylinder between the engine 1 and the throttle valve 3 and slightly upstream of the intake valve (not shown) in the intake pipe 2, and each injection valve is connected to a fuel pump (not shown). The valve opening time of fuel injection is controlled by a signal from the ECU 5 that is electrically connected to the ECU 5.

The spark plug 16 of each cylinder of the engine 1 is E
It is electrically connected to the CU 5, and the ignition timing θIG is controlled by the ECU 5.

On the other hand, an intake pipe absolute pressure (PBA) sensor 7 is provided immediately downstream of the throttle valve 3, and the absolute pressure signal converted into an electric signal by the absolute pressure sensor 7 is supplied to the ECU 5. . Further, an intake air temperature (TA) sensor 8 is attached downstream thereof, detects the intake air temperature TA, outputs a corresponding electric signal, and supplies it to the ECU 5.

The engine water temperature (TW) sensor 9 mounted on the main body of the engine 1 is composed of a thermistor or the like, detects the engine water temperature (cooling water temperature) TW, outputs a corresponding temperature signal and supplies it to the ECU 5. The engine speed (NE) sensor 10 and the cylinder discrimination (CYL) sensor 11 are mounted around the cam shaft or crank shaft (not shown) of the engine 1. The engine speed sensor 10 outputs a pulse (hereinafter referred to as a "TDC signal pulse") at a predetermined crank angle position every 180 degrees rotation of the crank shaft of the engine 1, and the cylinder discrimination sensor 11 outputs a predetermined crank angle of a specific cylinder. A signal pulse is output at the position, and each of these signal pulses is supplied to the ECU 5.

The three-way catalyst 14 is arranged in the exhaust pipe 13 of the engine 1 and purifies components such as HC, CO and NOx in the exhaust gas. The O ₂ sensor 12 as an exhaust gas concentration detector is installed on the upstream side of the three-way catalyst 14 in the exhaust pipe 13, detects the oxygen concentration in the exhaust gas, and outputs a signal corresponding to the detected value to output the ECU 5 Supply to.

Next, the exhaust gas recirculation mechanism 20 will be described.

The exhaust gas recirculation path 21 of this mechanism 20 has one end 2
1a communicates with the upstream side of the three-way catalyst 14 of the exhaust pipe 13, and the other end 21b communicates with the downstream side of the throttle valve 3 of the intake pipe 2.
An exhaust gas recirculation valve (recirculation gas control valve) 22 for controlling the amount of exhaust gas recirculation and a volume chamber 21C are provided in the middle of the exhaust gas recirculation passage 21. The exhaust gas recirculation valve 22 is a solenoid valve having a solenoid 22a, and the solenoid 22a is E
The valve opening is connected to the CU 5 and can be linearly changed by a control signal from the ECU 5. The exhaust gas recirculation valve 22 is provided with a lift sensor 23 that detects the valve opening degree, and the detection signal is supplied to the ECU 5.

The ECU 5 determines the engine operating state based on the engine parameter signals from the above-mentioned various sensors and the like, and the valve opening degree of the exhaust gas recirculation valve 22 set according to the intake pipe absolute pressure PBA and the engine speed NE. Command value LCMD
And the exhaust gas recirculation valve 22 detected by the lift sensor 23
A control signal is supplied to the solenoid 22a so as to make the deviation from the actual valve opening value LACT of 0.

In this embodiment, the ECU 5 constitutes a fuel amount calculation means, a recirculation gas control means, a recirculation gas amount calculation means and a correction means.

The ECU 5 shapes input signal waveforms from various sensors, corrects the voltage level to a predetermined level, converts an analog signal value into a digital signal value, and the like, a central processing circuit (hereinafter referred to as a central processing unit). "CPU") 5b, various calculation programs executed by the CPU 5b, storage means 5c for storing the calculation results, an output circuit 5d for supplying a drive signal to the fuel injection valve 6, and the like.

The CPU 5b discriminates various engine operating states such as a feedback control operating region to the stoichiometric air-fuel ratio by the O ₂ sensor 12 and an open loop control operating region based on the above-mentioned various engine parameter signals, and at the same time, the engine operating state. Accordingly, the fuel injection time Tout of the fuel injection valve 6 and the ignition timing θIG of the spark plug 16 are calculated based on the following equations (1) and (2).

Tout = TIM × K1 + K2 (1) θIG = θMAP + θCR (2) Here, TIM is a basic fuel amount, specifically, a basic value determined according to the engine speed NE and the intake pipe absolute pressure PBA. Fuel injection time.

Further, θMAP is also a basic ignition timing set according to the engine speed NE and the intake pipe absolute pressure PBA. As will be described later, the TIM value and the θMAP value are not only the NE value and the PBA value, but also the exhaust gas recirculation valve 22 and the exhaust gas recirculation gas dynamic characteristics, which are calculated when the exhaust gas recirculation is executed. It is set to a value according to.

K ₁ and K ₂ of the equation (1) and θCR of the equation (2)
Is a correction coefficient or a correction variable calculated according to various engine parameter signals, and is determined to a predetermined value that optimizes various characteristics such as fuel consumption characteristics and engine acceleration characteristics according to the engine operating state. It

The CPU 5b further controls the valve opening degree of the exhaust gas recirculation valve 22 of the exhaust gas recirculation mechanism 20 according to the engine operating state.

The CPU 5b outputs a signal for driving the fuel injection valve 6, the spark plug 16 and the exhaust gas recirculation valve 22 via the output circuit 5d based on the result of calculation and determination as described above.

FIG. 2 is a flow chart of a program for calculating the basic fuel amount TIM and the basic ignition timing θMAP corresponding to the opening / closing of the exhaust gas recirculation valve (hereinafter referred to as “EGR valve”) 22. This program is executed in synchronization with each generation of the TDC signal pulse. In addition, in the following description, when the EGR valve 22 is opened is referred to as “when EGR is on”.
When the valve is closed, it is called “when EGR is off”.

In step S1, the current value FEGR (n) of the EGR flag, which is set to 1 when EGR is turned on, is 1
Whether the answer is affirmative (YES) or negative (NO), the previous value FEGR (n of the EGR flag is determined.
-1) is a value 1 (steps S2, S1)
1).

The answer to step S1 is negative (NO) and the answer to step S2 is positive (YES), that is, FEGR (n) = 0.
When FEGR (n-1) = 1, the number of executions of the program (T
A predetermined value Noff (for example, 12) is set to the off counter CEoff that counts the number of times the DC signal pulse is generated (step S3), and the process proceeds to step S4.

Both the answers in steps S1 and S2 are negative (NO), that is, FEGR (n) = FEGR (n-1) =.
When it is 0, the process immediately proceeds to step S4, and it is determined whether or not the count value of the off counter CEoff is 0. If the answer to step S4 is negative (NO), that is, CEoff> 0, the off counter CEoff is decremented by 1 (step S7), and the mode status SEcal is determined.
Is set to the value 2 (step S8). This mode status SEcal is set to EGR in the following step S9.
Is used to distinguish between the on-state or the off-state, or the on-state or the off-state and vice versa, and the value 2 indicates the on-state to the off-state.

In the following steps S9 and S10, the basic fuel amount TIM is calculated by executing the programs of FIGS. 3 and 4 described later, and the basic ignition timing θMAP is calculated by the program of FIG. 5 described later. This program ends.

The answer to step S4 is affirmative (YES),
That is, when CEoff = 0, it means that a predetermined number (Noff) of TDC signal pulses have occurred after the transition to the EGR off state, and it is considered that the off state is stable. Therefore, the value 3 is set to the mode status SEcal ( Step S5). A value of 3 indicates that the EGR is off. Next, when EGR is off, that is, the normal TIM value and θMA
The P value is calculated (step S6), and this program ends.

When the answer to step S1 is affirmative (YES) and the answer to step S11 is negative (NO), that is, FEG
When R (n) = 1 and FEGR (n-1) = 0,
A predetermined value Non (for example, 10) is set to an on-counter CEon that counts the number of executions of this program after the transition from the EGR off state to the on state (step S12),
It proceeds to step S13.

Both the answers in steps S1 and S11 are affirmative (YES), that is, FEGR (n) = FEGR (n-1).
When = 1, the process immediately proceeds to step S13, and it is determined whether or not the count value of the on counter CEon is 0. If the answer to step S13 is negative (NO), that is, CEon> 0, the off counter CEon is decremented by 1 (step S18), and the mode status SEcal is determined.
Is set to 0 (step S19). Value 0 is EGR
Indicates a transitional state from the off state to the on state.

In the following steps S20 and S21, the programs of FIGS. 3 to 5 are executed as in steps S9 and S10, and this program ends.

The answer in step S13 is affirmative (YE
S), that is, CEon = 0, means that a predetermined number (Non) of TDC signal pulses have occurred after the transition to the EGR ON state, and it is considered that the ON state is stable.
The value 1 is set to the mode status SEcal (step S15). A value of 1 indicates that the EGR is on. In the following steps S16 and S17, the programs of FIGS. 3 to 5 are executed, and this program is terminated, as in steps S9 and S10.

FIG. 3 shows the basic fuel amount TIM in steps S9, S16 and S20 of the program shown in FIG.
6 is a flowchart of a program for calculating

In steps S31 to S33, the basic fuel amount TIM, the EGR coefficient KEGR, and the dead time τ are calculated according to the detected engine speed NE and the intake pipe absolute pressure PBA. These parameters TIM, KEGR and τ
Is calculated by detecting a map set according to the NE value and the PBA value, and performing an interpolation operation as necessary.

The EGR coefficient KEGR is a coefficient for correcting the TIM value in the decreasing direction, considering that the intake air amount is substantially reduced because the inert gas is recirculated to the intake system when the EGR is turned on. .. Note that (1-KEGR) is
It corresponds to the recirculation rate EGRR / R. Also, the dead time τ is
This corresponds to the time required for the reflux gas that has passed through the EGR valve 22 to reach the combustion chamber, and in this embodiment, the time is represented by the number of times the TDC pulse is generated. This dead time τ is set to a larger value as the PBA value increases and the NE value increases as shown in FIG. 6, for example.

In subsequent steps S34 and S35, the net EGR coefficient KEGRN is calculated by the program shown in FIG. 4, and the TIM value is corrected by the following equation (3) (step S34).
35) This program ends.

TIM = TIM × KEGRN (3) In steps S41 to S43 of FIG. 4, the value of the mode status SEcal set by the program of FIG. 2 is 0,
If the answer is negative (NO), that is, if the value of SEcal is neither 0 nor 2, SEcal = 3 and the EGR is off, so the EGR recirculation gas is Since it is not necessary to calculate the amount, this program ends immediately.

When the answer to step S41 is affirmative (YES), that is, when SEcal = 0, it means that the transition from the EGR-off state to the on-state has just occurred, so that the EG at the time of EGR off-on is on.
The R direct rate EAN and the EGR take-away rate EBN are calculated (steps S44 to S46), and the answer in step S42 is affirmative (YES), that is, when SEcal = 1, the EGR is in the ON state, so the EGR direct rate EA and EGR carry-out EB is calculated (steps S47, S48), and the answer in step S43 is affirmative (YES), that is, when SEcal = 2, it is immediately after the transition from the EGR on state to the off state. EGR direct rate EAF and E
The GR take-away rate EBF is calculated (steps S49 to S49).
51) and the process proceeds to step S52.

Here, the EGR direct ratio EA is the ratio of the gas that is sucked into the combustion chamber during the cycle to the recirculated gas that has passed through the EGR valve 22 in a certain cycle.
The EGR carry-out rate EB is the recirculation gas that has passed through the EGR valve 22 and accumulated from the EGR valve 22 to the combustion chamber (mainly the volume chamber 21C) up to the previous time, and is sucked into the combustion chamber during the cycle. It is the ratio of the gas to be discharged. The EGR direct rate EA and the EGR carry-out rate EB are the engine speed NE detected before τTDC from the EA map and the EB map set according to the engine speed NE and the intake pipe absolute pressure PBA as shown in FIG. (Τ) and the intake pipe absolute pressure PBA (τ) are read (step S4).
7, S48). Here, “τ” means the step S33 in FIG.
It was calculated in. As the value before τTDC, for example, the detected value for the past 20TDC is stored in the memory and read according to the τ value.

The EGR direct ratios EAN and EAF at the time of EGR off-on and at the time of EGR on-off are also set to values corresponding to the dynamic characteristics of the recirculated gas in the respective transient states, and the EAN map and the EAF map (map format) Figure 7
Is the same as the above), and is read according to the NE (τ) value and the PBA (τ) value (steps S44 and S49). Further, the EGR carry-off rates EBN and EBF at the time of EGR off-on and at the time of on-off are similarly calculated (steps S45, S50). The EAN map, the EAF map, the EBN map, and the EBF map indicate that the response delay of the EGR valve 22 (after the control signal is output from the ECU 5,
The time taken until the opening degree of the R valve 22 reaches the command value) is also taken into consideration.

In step S52, according to the following equation (4),
The required recirculation gas amount (apparently, the recirculation gas amount that has passed through the EGR valve 22) gt is calculated.

Gt = TIM (τ) × (1−KEGR (τ)) (4) Here, (τ) indicates a value calculated before τTDC.

In the following step S53, the true recirculation gas amount gin drawn into the combustion chamber is calculated by the following equation (5).

Gin = EA × gt + EB × gc (5) where gc is the amount of recirculation gas that has accumulated in the volume chamber 21c etc. after passing the EGR valve, and is calculated in step S55 described later at the time of executing the present program last time. It was done.

In the following step S54, the net EGR coefficient KEGRN is calculated by the following equation (6).

KEGRN = 1-gin / TIM (6) Further, in step S55, the amount of staying gas g is calculated by the following equation (7).
After calculating c, the program is terminated.

Gc = (1−EA) × gt + (1−EB) × gc (7) Here, gc on the right side is a previously calculated value.

According to the program of FIG. 4, the EGR direct rate EA and the take-away rate EB are the dead time of the reflux gas (the time from the passage of the gas through the EGR valve to the combustion chamber) and the opening / closing of the EGR valve. Since the values are set in consideration of the response delay at the time of operation, the true intake gas amount gin obtained by applying these to the equation (5) determines the dynamic characteristics of the reflux gas, that is, the dead time and the volume chamber. Of the amount of gas to be used and the EGR valve 22
Is a value that takes into account the dynamic characteristics of the above, and accurately represents the amount of recirculated gas that is taken into the combustion chamber. Therefore, by multiplying the basic fuel amount TIM by the net EGR coefficient KEGRN obtained by the equation (6) (step S35 in FIG. 3), the accurate basic fuel amount TIM in consideration of the influence of the recirculation gas is obtained.
Can be obtained, and the air-fuel ratio of the air-fuel mixture supplied to the combustion chamber can be maintained at a desired value.

FIG. 5 is a flow chart of a program for calculating the basic ignition timing θMAP.

In step S61, the engine speed NE
And the NE value and PB detected from the EMAP off-time θMAP map set in accordance with the intake pipe absolute pressure PBA.
The basic ignition timing θMAPO when EGR is turned off is read according to the A value, and the EGR set in the same manner is set in step S62.
NE value and P detected from the θMAP map for ON
Basic ignition timing θMAPT when EGR is on according to BA value
Read out.

In the following step S63, the basic ignition timing θMAP is calculated by the following equation (8).

ΘMAP = (θMAPT−θMAPO) × (1−KEGRN) / (1−KEGR) + θMAPO (8) According to the equation (8), KEGRN = 1 when EGR is off (the above equation (6)). In this case, gin = 0 in the above), so θMAP = θMAPO, while θMA = θEGPO when EGR is on.
In the state of P = θMAPT and KEGR ≠ KEGRN, the θMAP value is a value obtained by linearly interpolating the θMAPT value and the θMAPO value (see FIG. 8). This means that even if the actual θMAP value with respect to (1-KEGRN) / (1-KEGR) has a characteristic as indicated by the broken line, as shown in an example in FIG. 8, the θMAP values are θMAPT values and θMAPO values. This is because even if a value obtained by linearly interpolating the value is used, a value having substantially no problem can be obtained. Thus, when the EGR is on, the basic ignition timing θ is calculated using the net EGR coefficient KEGRN calculated according to the dynamic characteristics of the EGR valve and the recirculation gas.
Since the MAP is determined, the ignition timing can be accurately controlled to a desired value.

In this embodiment, the EGR valve 22
The valve opening command value LCMD is set to a value according to the EGR coefficient KEGR.

FIG. 9 shows an EG according to another embodiment of the present invention.
7 is a flowchart of a program for controlling the valve opening degree of the R valve 22.

In step S71, the EGR coefficient KEGR is calculated according to the engine speed NE and the intake pipe absolute pressure PBA detected as in step S32 of FIG. In the following step S72, the EGR direct rate EA and the EGR take-away rate EB are calculated in accordance with the NE value and the PBA value before τTDC, as in steps S41 to S51 in FIG. 4 described above.

In the following step S73, the recirculation gas amount (supply recirculation gas amount) to be supplied to the combustion chamber is calculated by the following equation (9).
Calculate gw.

Gw = TIM × (1−KEGR) (9) Next, the recirculation gas amount (passage recirculation gas amount) gt to be passed through the EGR valve 22 is calculated by the following equation (10) (step S74).

Gt = (gw−EB × gc) / EA (10) Here, gc is the amount of staying recirculation gas calculated during the previous execution of step S78, which will be described later (residence from the EGR valve to the combustion chamber). And the amount of reflux gas). Formula (10)
Corresponds to a modification of eq. (5) where gin is gw and gt is calculated. Therefore, the formula (1
The gt value obtained by 0) is the amount of passing recirculation gas in which the dynamic characteristics of the EGR valve 22 and the recirculation gas are reflected. That is, if the recirculation gas is allowed to pass through the EGR valve 22 by this gt value, the desired supply recirculation gas amount gw can be obtained.

Next, at step S75, the passage recirculation rate EGRVR / R which is the recirculation rate focusing on the amount of gas passing through the EGR valve 22 is calculated by the following equation (11). At this time, the recirculation rate EGRR / R of the recirculated gas to the combustion chamber is gw /
It becomes TIM (= 1-KEGR).

EGRVR / R = gt / TIM (11) In the next step S76, EGR is calculated according to the passage recirculation rate EGRVR / R calculated by the equation (11), the engine speed NE and the intake pipe absolute pressure PBA. The valve opening command value LCMD of the valve 22 is calculated. This calculation is performed, for example, in FIG.
As shown in, the engine speed NE is the predetermined speed NE10.
At (for example, 1000 rpm), the LCMD map set according to the EGRVR / R value and the PBA value is set to a plurality of predetermined engine speeds (for example, 2000, 2500,
It is provided for each 3000 rpm) and is read from these LCMD maps according to the EGRVR / R value, NE value and PBA value.

In the following step S77, the valve opening command value L
CMD is output, and then step S55 of FIG. 4 described above.
Similarly, the staying recirculation gas amount gc is calculated by the equation (7) (step S78), and the present program is terminated.

According to this embodiment, the valve opening degree of the EGR valve 22 is such that the desired recirculation rate EGRR / R (= gw / TIM = 1-
Since the control is performed in consideration of the dynamic characteristics of the EGR valve and the recirculation gas so as to obtain KEGR), it is not necessary to calculate the net EGR coefficient KEGRN as in the first embodiment described above, and the EGR coefficient KEGR is not required. A desired air-fuel ratio and ignition timing can be obtained from the basic fuel amount TIM and the basic ignition timing θMAP calculated using

[0068]

As described above in detail, according to the control device of the first aspect, the recirculation gas amount is calculated based on the dynamic characteristics of the recirculation gas control valve and the recirculation gas, the engine speed and the load state. , The amount of fuel supplied is corrected according to the amount of recirculated gas, so the air-fuel ratio of the air-fuel mixture supplied to the combustion chamber of the engine during execution of exhaust gas recirculation and during transition from the execution state to the stopped state or vice versa By properly controlling, the exhaust gas characteristics and drivability of the engine can be further improved.

Further, according to the control device of the second aspect, the control amount of the recirculation gas control valve is calculated based on the dynamic characteristics of the recirculation gas control valve and the recirculation gas, and the state of the engine speed and load. Therefore, the amount of recirculated gas actually sucked into the combustion chamber of the engine can be accurately controlled, and the same effect as that of the control device according to claim 1 can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an internal combustion engine and its control device according to an embodiment of the present invention.

[FIG. 2] Basic fuel amount (TI
7 is a flowchart of a program for calculating M) and a basic ignition timing (θMAP).

3 is a flowchart of a basic fuel amount calculation program executed by the program of FIG.

4 is a flowchart of a net EGR coefficient (KEGRN) calculation program executed by the program of FIG.

5 is a flowchart of a basic ignition timing calculation program executed by the program of FIG.

FIG. 6 is a diagram showing a map for calculating a dead time (τ) of reflux gas.

FIG. 7: EGR direct rate (EA) and take-away rate (EB)
It is a figure which shows the map for calculating.

FIG. 8: Basic ignition timing (θMAP) and EGR coefficient (KE
It is a figure which shows the relationship with GR.

FIG. 9 is a flowchart of a program for controlling the valve opening degree of an exhaust gas recirculation valve.

FIG. 10 is a diagram showing a map for calculating a valve opening command value (LCMD) for exhaust gas recirculation.

[Explanation of symbols]

 1 Internal Combustion Engine 2 Intake Pipe 5 Electronic Control Unit (ECU) 6 Fuel Injection Valve 13 Exhaust Valve Pipe 20 Exhaust Gas Recirculation Mechanism 22 Exhaust Gas Recirculation Valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kei Machida 1-4-1, Chuo, Wako, Saitama Prefecture

Claims (3)

[Claims] 1. A control device for an internal combustion engine having an exhaust gas recirculation mechanism including a recirculation gas control valve for controlling recirculation of exhaust gas to an intake system, the engine being based on a rotational speed and a load state of the engine. A fuel amount calculation means for calculating the amount of fuel to be supplied to, and a recirculation gas amount control means for controlling the recirculation gas amount by controlling the recirculation gas control valve based on the operating state of the engine, The recirculation gas control valve and the recirculation gas dynamic characteristics, the recirculation gas amount calculation means for calculating the recirculation gas amount based on the engine speed and the load condition, and the supply fuel amount according to the recirculation gas amount. A control device for an internal combustion engine, comprising: a correction means for correcting. 2. A control device for an internal combustion engine having an exhaust gas recirculation mechanism including a recirculation gas control valve for controlling recirculation of exhaust gas to an intake system, the recirculation gas control valve being based on an operating state of the engine. In a control device having a recirculation gas amount control means for controlling the recirculation gas amount by controlling, the recirculation gas amount control means comprises the recirculation gas control valve and the recirculation gas dynamic characteristics, and the engine speed and load condition. A control device for an internal combustion engine, wherein the control amount of the recirculation gas control valve is calculated based on 3. A control device for an internal combustion engine, comprising an exhaust gas recirculation mechanism including a recirculation gas control valve for controlling recirculation of exhaust gas to an intake system, the engine being based on a rotational speed and a load state of the engine. Ignition timing calculation means for calculating the ignition timing of
In a control device having a recirculation gas amount control means for controlling the recirculation gas amount by controlling the recirculation gas control valve based on the operating state of the engine, the recirculation gas control valve and the recirculation gas dynamic characteristics, and the engine. Of the internal combustion engine, which is provided with a recirculation gas amount calculation means for calculating the recirculation gas amount based on the number of revolutions of the engine and a load state, and a correction means for correcting the ignition timing according to the recirculation gas amount. Control device.