JP3387404B2 - Engine control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine control device having an electronically controlled throttle device and an EGR control device.

[0002]

2. Description of the Related Art As an engine control device equipped with an EGR device (exhaust gas recirculation device), there is, for example, one proposed by the applicant of the present application as Japanese Patent Application No. 9-152591.

In order to improve the accuracy of EGR control, a target torque equivalent value is calculated from the accelerator opening (accelerator pedal depression amount) and the engine speed,
The target intake air amount is calculated by converting them to the basic intake air amount, that is, the equivalent value of the required cylinder intake air amount at the reference air-fuel ratio, and multiplying them by the target equivalence ratio, and the target EGR rate and the target intake air amount described above The amount of EGR is calculated. Further, the target EGR amount is corrected to a value equivalent to the fresh air amount, the correction value and the target intake air amount are added to calculate the total working gas amount, and the total opening area is calculated from the total working gas amount. Is assigned to the target throttle opening and the target EGR valve opening according to the target intake air amount, the target EGR amount, and the total working gas amount.

By the way, generally, the relationship between the throttle opening and the engine torque and the cylinder intake air amount is as shown in FIG. 1, and the region where the engine torque and the cylinder intake air amount hardly increase with the increase of the throttle opening amount. (Hatched portion in the figure) exists. This is because the pressure difference between the upstream and downstream of the throttle valve disappears as the throttle opening increases. The same can be said for the EGR valve. Therefore, in the control device as described above, in the throttle opening range, for example, even if a slight bit error (error) of the accelerator opening sensor output APO or fine movement due to vibration or the like occurs, as shown in FIG. Opening TVO and EGR valve opening EGR
As a result, / V relatively excessively reacts, which may cause problems such as torque fluctuations that impair drivability. The present invention aims to solve such problems.

[0005]

The invention according to claim 1 is based on FIG.
As shown in FIG. 5, a throttle control device Tc that controls the opening of the throttle valve so as to achieve a predetermined target throttle opening based on the engine operating state including the accelerator opening and the engine speed, and the engine operating state Based on this, an engine control device is provided with an EGR control device Ec for controlling the opening of the EGR valve so as to obtain a predetermined target EGR amount, and the accelerator opening APO and the engine speed Ne are set.
And from the theoretical air-fuel ratio target intake air amount equivalent value TTPST
And a target equivalence ratio calculation unit that calculates a target equivalence ratio TFBYA00 from the accelerator opening APO and the engine speed Ne, and a target intake air amount equivalent value TTP.
A second target intake air amount calculation unit that calculates the second target intake air amount equivalent value TTP by dividing ST by the target equivalence ratio TFBYA00, and a target E from the accelerator opening APO and a predetermined operating state detection value.
From the target EGR rate calculation unit that calculates the GR rate TEGR and the target intake air amount TTPST and the target EGR rate TEGR, the target E is calculated.
A target EGR amount calculation unit for calculating the GR amount TPEGR,
The second target intake air amount equivalent value TT is added to the target EGR amount TTPEGR.
A target total working gas amount calculation unit that calculates the target total working gas amount TTPGAS0 by adding P, a target total working gas amount limit value calculation unit that calculates the target total working gas amount limit value GASLMT, and a target total working gas amount Based on the result of the comparison, a total working gas amount comparison calculation unit for comparing TTPGAS0 with the target total working gas amount limit value GASLMT, and a target total working gas amount TT
When PGAS0 is larger than the target total working gas amount limit value GASLMT, a target EGR rate correction calculation unit that corrects the target EGR rate in a decreasing direction for a predetermined period, a second target intake air amount equivalent value TTP or a target EGR amount TPEGR, and a target total amount. A control system having a target throttle opening degree TTVO of the throttle control device Tc and a target opening degree calculation unit for calculating the target EGR valve opening degree TSTP of the EGR control device Ec from the working gas amount TTPGAS0 is provided.

According to a second aspect of the present invention, the target opening calculation section of the above-mentioned invention calculates the total opening area TAGAS of the throttle valve and the EGR valve based on the target total working gas amount TTPGAS0 and the engine speed Ne, and The opening area TAAIR for the valve and the opening area TAEGR for the EGR valve are calculated by the following formulas: TAAIR = TAGAS × TTP / TTPGAS0 TAEGR = TAGAS × TTPEGR / TTPGAS
The target throttle opening TTVO is calculated based on the opening area TAAIR of the throttle valve portion.
The GR valve opening TSTP is equal to the opening area T of the EGR valve.
The calculation is performed based on the AEGR.

According to the invention of claim 3, as shown in FIG.
A throttle control device Tc for controlling the opening of the throttle valve so as to reach a predetermined target throttle opening based on the engine operating state including the accelerator opening and the engine speed.
And an EGR control device Ec that controls the opening of the EGR valve so that a predetermined target EGR amount is obtained based on the engine operating state, and the accelerator opening APO and the engine speed Ne are configured. The target intake air amount calculation unit that calculates the target intake air amount equivalent value TTPST at the theoretical air-fuel ratio, the accelerator opening APO, and the engine speed Ne.
From the target equivalence ratio TFBYA00, and a target equivalence ratio equivalent value TTPST to the target equivalence ratio T
A second target intake air amount calculation unit that calculates a second target intake air amount equivalent value TTP by dividing by FBYA00, and a target EGR ratio calculation unit that calculates a target EGR ratio TEGR from the accelerator opening APO and a predetermined operating state detection value. , The target intake air amount TTPST and the target EGR rate TEGR, the target EGR amount TPEGR
And a target EGR amount TTP for calculating the target EGR amount
A target total working gas amount calculator that calculates the target total working gas amount TTPGAS0 by adding the second target intake air amount equivalent value TTP to EGR, and a target total working gas amount limit value that calculates the target total working gas amount limit value GASLMT Calculation unit, target total working gas amount TTPGAS0 and target total working gas amount limit value GASLM
When the target total working gas amount TTPGAS0 exceeds the target total working gas amount limit value GASLMT as the second target total working gas amount TTPGAS, based on the comparison result, the total working gas amount comparison calculation unit that compares T with T is the target total working gas amount. The working gas amount limit value GASLMT is set to the target total working gas amount TTPGA.
Second setting of target total working gas amount TTPGAS0 when S0 is equal to or less than target total working gas amount limit value GASLMT
From the target total working gas amount setting calculation unit, the second target intake air amount equivalent value TTP or the target EGR amount TTPEGR, and the second target total working gas amount TTPGAS, the target throttle opening TTVO of the throttle control device Tc and the EGR control device Ec are calculated. A control system having a target opening calculation unit for calculating the target EGR valve opening TSTP is provided.

According to a fourth aspect of the present invention, the target opening degree calculating section of the third aspect of the invention is provided with a second target total working gas amount TTPGAS.
And engine speed Ne based on the throttle valve and EG
The total opening area TAGAS of the R valve is calculated, and the opening area TAAIR of the throttle valve and the opening area TAEGR of the EGR valve are calculated based on the following equations: TAAIR = TAGAS * TTP / TTPGAS TAEGR = TAGAS * TTPEGA / TTPGAS. The target throttle opening TTVO is calculated based on the opening area TAAIR for the throttle valve.
The opening area T of the GR valve opening TSTP is equal to the opening area T of the EGR valve.
The calculation is performed based on the AEGR.

According to a fifth aspect of the present invention, the second target total working gas amount calculation unit of the third aspect of the invention is provided with a target total working gas amount TT.
The sum of the second target EGR amount obtained by subtracting the excess amount of PGAS0 from the target total working gas amount limit value GASLMT from the target EGR amount TTPEGR and the second target intake air amount equivalent value TTP is set as the second target total working gas amount TTPGAS. Configured to set.

According to a sixth aspect of the present invention, the control system according to the fifth aspect of the present invention is configured such that the target total working gas amount TTPGAS0 exceeds the target total working gas amount limit value GASLMT by a target EG.
A target equivalent ratio correction calculation unit for correcting the target equivalent ratio TFBYA00 when the second target EGR amount subtracted from the R amount TTPEGR becomes zero or less is provided.

According to a seventh aspect of the present invention, the target equivalence ratio correction calculation section of the sixth aspect of the invention is provided with a target total working gas amount TTPGA.
The second target total working gas amount TTP that is less than or equal to zero of the second target EGR amount obtained by subtracting the excess amount of S0 from the target total working gas amount limit value GASLMT from the target EGR amount TTPEGR.
The target equivalence ratio is corrected in the direction of increasing the air-fuel ratio by the ratio to GAS.

According to an eighth aspect of the present invention, the target total working gas amount calculating section of the first or third aspect of the invention is provided with a target EGR.
Conversion factor KQE determined according to the operating state including at least one of exhaust pressure and exhaust temperature
Target EGR amount corrected by GR Fresh air conversion value TPEGPA
With the target EGR amount as the target total working gas amount TTPGAS0
Is configured to be calculated.

[0013]

According to the first and second aspects of the present invention, the EGR amount is maximally zero in a region where the intake air amount and the EGR amount change little with respect to changes in the throttle opening amount and the EGR valve opening amount. Will be reduced to. In this case, the throttle opening and EGR are also controlled in the engine that controls the air-fuel ratio in a wide range.
The second target intake air amount equivalent value TTP = GASLMT without using the region as shown in FIG.
Since the required fresh air amount can be secured until the above condition, the engine output (air amount) required by the driver can be secured without causing a phenomenon that impairs drivability as shown in FIG.

In particular, according to the invention of claim 2, only one limit value GASLMT is required for the calculation, and the fresh air and EGR
It is not necessary to set for each gas, and the calculation becomes easier.

According to the third and subsequent aspects of the invention, the intake air amount, the EG
In the region where the R amount changes little, the EGR amount is reduced according to the amount in which the EGR amount exceeds the limit value. In this case, even in an engine that controls the air-fuel ratio in a wide range, the throttle opening,
Since the EGR valve opening does not use the region as shown in FIG. 1, the engine output (air amount) required by the driver is secured without causing the phenomenon as shown in FIG. 2 that impairs drivability. can do.

In particular, according to the invention of claim 4, only one limit value GASLMT is necessary for the calculation, and it is not necessary to set each of the fresh air and the EGR gas, and the calculation becomes easier.

Further, according to the invention of claim 5, the required fresh air amount can be secured until the second target intake air amount equivalent value TTP = GASLMT, so that the phenomenon of impairing drivability as shown in FIG. 2 occurs. It is possible to more reliably avoid the engine output required by the driver.

Further, according to the sixth aspect of the invention, even if the second target intake air amount equivalent value TTP = GASLMT is satisfied, the shortage of the required fresh air amount can be corrected by the equivalence ratio, so as shown in FIG. It is possible to more reliably secure the engine output required by the driver while more reliably avoiding a phenomenon that impairs various drivability.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In addition, in the following description of the embodiments, it is assumed that the respective arithmetic units configuring the control system of the respective inventions are configured as a control unit including a microcomputer.

FIG. 5 shows an example of the construction of an engine to which the present invention can be applied. In the figure, 1 is an accelerator opening sensor, which detects the opening of an accelerator pedal operated by a driver. Further, FIG. 2 shows a crank angle sensor which constitutes an engine operating condition detecting means, which generates a position signal for each unit crank angle for cylinder discrimination and a reference signal for each cylinder stroke phase difference. The engine speed is detected by measuring the number of occurrences per hour or by measuring the reference signal generation period. 3 is also 1 of the operating state detecting means
The air flow meter, which is one of the two, detects the amount of intake air to the engine 4 (the amount of intake air per unit time). Reference numeral 5 is a water temperature sensor 5 which is also one of operating state detecting means, and detects the cooling water temperature of the engine.

The engine 4 is provided with a fuel injection valve 6 which is driven by a fuel injection signal to directly inject fuel into the combustion chamber, and an ignition plug 7 which is mounted in the combustion chamber and ignites. The direct injection method into the combustion chamber enables lean formation by stratified combustion, and the air-fuel ratio can be variably controlled over a wide range. Further, in the intake passage 8 of the engine 4,
A throttle valve 9 is provided, and the throttle valve 9
An electronically controlled throttle device 10 is provided for electronically controlling the opening degree of the DC motor or the like.

Detection signals from the various sensors are input to a control unit 11, which controls the throttle device 10 according to an operating state detected based on the signals from the sensors. The fuel injection valve 6 is controlled by controlling the opening of the throttle valve 9.
Is controlled to control the fuel injection amount (fuel supply amount), the ignition timing is set, and the ignition plug 7 is ignited at the ignition timing.

An EGR valve 14 is provided in an EGR passage 13 connecting the exhaust passage 12 and the intake passage 8 of the engine 4, and an electronically controlled EGR valve for electronically controlling the opening of the EGR valve 14 by a step motor or the like. A device 15 is provided.

As will be described later, the control unit 11 calculates a target intake air amount based on the accelerator opening APO and the engine speed Ne, and drives the throttle device 10 so as to obtain the target intake air amount. A signal is output to control the opening of the throttle valve 9 and
Exhaust gas recirculation is performed in a predetermined engine operating region represented by the engine load TP and the engine speed Ne represented by the accelerator opening APO and the fuel injection amount, and the target EGR rate (EGR
A drive signal is output to the EGR valve device 15 to control the opening degree of the EGR control valve 14 so that the gas amount / intake amount) can be obtained.

In FIG. 3, reference numeral 16 is an air-fuel ratio sensor for detecting the concentration of a specific component such as oxygen in the exhaust gas to detect the air-fuel ratio of the air-fuel mixture.

FIG. 5 is a flow chart showing the operation contents of the control system applied to the above engine structure, and FIG. 6 is a calculation block diagram of the control system, which are generally embodiments corresponding to the invention of claim 1 above. Is shown. The control according to the present embodiment will be described below along these lines.

To the control unit, the accelerator opening APO from the accelerator opening sensor 1 and the engine speed Ne from the crank angle sensor 2 are input, and the target intake air amount TTPST at the theoretical air-fuel ratio is calculated (step 6).
01-603). As the target intake air amount TTPST, the basic fuel injection pulse width corresponding to the intake air amount for each intake stroke is used. Instead of the basic fuel injection pulse width, the intake amount per intake stroke itself, the intake amount per unit time, the fuel amount corresponding to these intake amounts at the stoichiometric air-fuel ratio, and the ratio to the maximum intake amount at the current engine speed Either may be used.

Accelerator opening APO and engine speed Ne
Then, the target equivalent ratio TFBYA00 is calculated (step 604). Here, the target equivalent ratio TFBYA00 may be changed according to, for example, the cooling water temperature. After that, the flag 1 is examined. When the flag 1 = 1, it means that the EGR prohibition state is set by the routine described later. Therefore, the target EGR rate TEGR is set to zero and the EGR is stopped until the predetermined time elapses, When the time has passed, the flag 1 is reset to 0 (steps 605 to 608).

In the state where the flag 1 = 0 (EGR is not prohibited), the target EGR rate TEGR is calculated from the accelerator opening APO or the target intake air amount and the engine speed Ne (step 609). Here, the target EGR rate T
The EGR may be changed according to, for example, the cooling water temperature or the target equivalent ratio.

Next, the target intake air amount TTPST is set to the target equivalence ratio T
The second target intake air amount TTP is calculated by dividing by FBYA00 (step 610).

Further, the target EGR amount TTPEGR is calculated by multiplying the target intake air amount TTP by the target EGR rate TEGR, and the target EGR amount fresh air conversion value TTPEGA0 is
The target EGR amount TTPEGR is obtained by correcting the target EGR amount TPEGR with a conversion coefficient KQEGR in consideration of exhaust pressure, temperature, etc. (step 611).

The target total working gas amount TTPGAS0 is the second
Target intake air amount TTP and target EGR amount Fresh air conversion value TTPEG
It is calculated by adding A and A (step 612).

Next, a predetermined target total working gas amount limit value GASLMT is calculated according to the engine operating state (step 613), and this and the target total working gas amount TTPG are calculated.
The magnitude relationship with AS0 is compared, and as a result of this comparison, TT
If PGAS0 is larger than GASLMT, GASLMT is substituted for the second target total working gas amount TTPGAS.
Then, the flag 1 which is the EGR prohibition flag becomes 1 and
As described above, EGR is prohibited for a certain period (steps 614 to 615). The EGR prohibition period may simply be the elapsed time after the EGR prohibition flag is set to 1. Also, for example, the previous value of TEGR is not equal to the present calculated value, and the previous value of TTPST is not equal to the present calculated value. It may be up to.

If TTPGASO is smaller than or equal to GASLMT, the target total working gas amount TTPGASO is substituted as the second target total working gas amount (step 61).
6).

The target total working gas amount limit value GASLMT
May be a fixed value. Further, it is desirable to provide hysteresis in GASLMT to prevent hunting in determination.

On the other hand, the second target total working gas amount TTPGAS
And the engine speed Ne based on the throttle valve and E
The total opening area TAGAS of the GR valve is calculated (step 617).

Throttle valve opening area TAAIR
Is the second target total working gas amount TT of the total opening area TAGAS
The ratio of the second target intake air amount TTP to PGAS is calculated as follows.

TAAIR = TAGAS × TTP / TTPGAS EGR valve opening area TAEGR is the total opening area T
The ratio of the target EGR amount fresh air conversion value TPEGGA to the second target total working gas amount TTPGAS of AGAS is calculated as follows.

TAEGR = TAGAS × TTPEGA / TTPGAS The target throttle opening TTVO is calculated according to the opening area TAAIR for the throttle valve, and the target EGR valve opening TSTP is the opening area TAEG for the EGR valve.
It is calculated according to R (step 618). The target throttle opening TTVO is a target throttle opening for supplying the second target intake air amount TTP which is the target intake air amount at a predetermined air-fuel ratio, and the target EGR valve opening TSTP is
At this time, the opening degree of the EGR valve is necessary to feed the recirculated gas so that the EGR rate becomes TEGR.

The electronically controlled throttle device is driven so that the actual opening TVO of the throttle valve 9 becomes the target throttle opening TTVO. Further, in the electronically controlled EGR valve, the actual opening EGR / V of the EGR valve 14 is the target EGR.
The valve opening TSTP is driven.

In the fuel injection amount control, the intake air amount Qa measured by the air flow meter 3 per unit time and the engine speed Ne are input, and the basic fuel injection corresponding to the intake amount per intake stroke at the theoretical air-fuel ratio is input. The pulse width TP is calculated.
The fuel injection pulse width TI is calculated by adding the invalid pulse width TS corresponding to the battery voltage to the effective fuel injection pulse width TE which is obtained by multiplying the basic pulse width TP by the target equivalent ratio TFBYA00. The fuel injection valve 6 is driven so that

According to this embodiment, as shown in FIG. 8n, EGR is prohibited in the region where the total working gas amount TTPGAS drawn into the engine exceeds the limit value GASLMT, and EGR is always made so that TTPGAS does not exceed GASLMT.
The amount is suppressed. Therefore, as shown in FIG. 9, the throttle valve opening TVO and the EGR valve opening EGR / V with respect to the slight movement and the error of the accelerator opening sensor output APO.
To avoid excessive fluctuations in engine torque and suppress fluctuations in engine torque.
Good drivability can be secured.

In this embodiment, the second target total working gas amount TTPGAS is set to correct the target EGR gas rate, but instead, the target total working gas amount TTPG is set.
AS0 is compared with the target total working gas amount limit value GASLMT, and when the target total working gas amount TTPGAS0 is larger than the target total working gas amount limit value GASLMT, the target EGR amount is corrected in a decreasing direction for a predetermined period or EGR is prohibited. The control may be simplified as follows.

FIG. 10 is a flow chart showing the operation contents of the control system according to the second embodiment, and FIG. 11 is a calculation block diagram of the control system, which generally correspond to the inventions of claims 3 and after. ing. The control according to the present embodiment will be described below along these lines.

The control unit has an accelerator opening A
PO and the engine speed Ne are input, and the target intake air amount TTPST at the theoretical air-fuel ratio is calculated (step 10
01-103). As the target intake air amount TTPST, the basic fuel injection pulse width TP corresponding to the intake air amount for each intake stroke is used. Of course, any of the intake air amount itself for each intake stroke, the intake air amount for each unit time, the fuel amount corresponding to these intake air amounts at the theoretical air-fuel ratio, and the ratio to the maximum intake air amount at the current engine speed may be used.

Next, the target equivalent ratio TFBYA00 is calculated from the accelerator opening APO and the engine speed Ne. The target equivalent ratio TFBYA00 may be changed according to, for example, the cooling long-term temperature. Also, TFBYA00 will be described later in KTF.
The second target equivalence ratio TFBYA is corrected by correcting with ALM.
01 is calculated (step 1004).

The target EGR rate TEGR is calculated based on the accelerator opening APO or the target intake air amount and the engine speed Ne (step 1005). Target EGR rate TEGR
May be changed according to, for example, the cooling water temperature or the target equivalence ratio.

The target intake air amount TTPST is set to the target equivalence ratio TFB.
The second target intake air amount TTP is calculated by dividing by YA00 (step 1006).

The target EGR amount TTPEGR is calculated by multiplying the target intake air amount TTP by the target EGR rate TEGR, and the target EGR amount fresh air conversion value TTPEGAO is the target E.
It is obtained by correcting the GR amount TPEGR with a conversion count KQEGR considering the exhaust pressure, temperature, etc. (step 10).
07).

The target total working gas amount TTPGASO is the second
Target intake air amount TTP and target EGR amount Fresh air conversion value TTPEG
It is calculated by adding A and (step 1008).

Next, a predetermined target total working gas amount limit value GASLMT is calculated according to the engine operating state (step 1009). Here, the target total working gas amount limit value GA
SLMT may be a fixed value. Also, GASLMT
It is desirable to provide a hysteresis to prevent hunting in determination.

As a result of comparing the target total working gas amount TTPGASO with the target total working gas amount limit value GASLMT, TPG
If AS0 is larger than GASLMT, GASLMT is substituted as the second target total working gas amount TTPGAS (steps 1010 to 1011). TTPGAS0 is GAS
If it is smaller than or equal to LMT, the target total working gas amount TTPGAS0 is substituted as the second target total working gas amount (step 1013).

Then, the difference between TTPGAS0 and GASLMT is calculated as TTP excess TTPEXD, and the second target EGR amount fresh air converted value TTPEGA is changed to the target EGR amount fresh air converted value TTPEGA and TTP excess TTP.
It is calculated by the difference from EXD (step 1012).

Here, the second target EGR amount fresh air conversion value TT
When PEGA becomes less than or equal to zero, the correction coefficient KTFALM of the target equivalence ratio TFBYA00 is calculated by the following equation in order to suppress the decrease in torque due to the decrease in fresh air amount due to the fixed TTPGAS (step 101).
4).

KTFALM = 1 + (TTPGAS0-T
TPGAS-TTPEGA) The correction coefficient KTFALM of the target equivalent ratio TFBYA00 is reflected by the following formula when the next TFBYA00 is calculated.

TFBYA01 = TFBYA00 × KTFALM Second target total working gas amount TTPGAS and engine speed N
The total opening area TAGAS of the throttle valve 9 and the EGR valve 14 is calculated from e (step 101).
5).

Throttle valve opening area TAAIR
Is the second target total working gas amount TT of the total opening area TAGAS
The ratio of the second target intake air amount TTP to PGAS is calculated as follows.

TAAIR = TAGAS × TTP / TTPGAS EGR valve opening area TAEGR is the total opening area T
The ratio of the target EGR amount fresh air conversion value TPEGGA to the second target total working gas amount TTPGAS of AGAS is calculated as follows.

TAEGR = TAGAS × TTPEGA / TTPGAS The target throttle opening TTVO is calculated according to the opening area TAAIR for the throttle valve, and the target EGR valve opening TSTP is the opening area TAEG for the EGR valve.
It is calculated according to R (step 1016). The target throttle opening TTVO is a target throttle opening for supplying a second target intake air amount TTP which is a target intake air amount at a predetermined air-fuel ratio, and the target EGR valve opening TSTP.
Is the EGR valve opening required to feed the recirculated gas such that the EGR rate becomes TEGR.

In the electronically controlled throttle device 10, the actual opening TVO of the throttle valve 9 is the target throttle opening TTV.
Driven to be O. The electronically controlled EGR valve device 15 is driven so that the actual opening EGR / V of the EGR valve 14 becomes the EGR valve opening TSTP.

The fuel injection amount control is performed by the intake air amount Qa measured by the air flow meter 3 per unit time and the engine speed Ne.
Is input, and the basic fuel injection pulse width TP corresponding to the intake amount of one intake stroke is calculated at the stoichiometric air-fuel ratio. The fuel injection pulse width TI is calculated by adding the effective fuel injection pulse width TE obtained by multiplying the basic pulse width TP by the second target equivalence ratio TFBYA01, and the invalid pulse width TS corresponding to the battery voltage, thereby obtaining the desired fuel. The fuel injection valve 6 is driven so that the injection amount is achieved.

According to this embodiment, the EGR amount is throttled so that the total working gas amount TTPGAS does not exceed the limit value GASLMT as in the previous embodiment, and the EGR amount becomes zero as a result of the suppression of the EGR amount. In this case, the target equivalence ratio TFBYA01 is corrected in the air-fuel ratio enrichment direction (see FIG. 12), so that the driving performance in the operating range where the throttle opening is large can be further improved.

[Brief description of drawings]

FIG. 1 is a characteristic diagram showing the relationship between throttle opening and engine torque (cylinder intake air amount) at a stoichiometric air-fuel ratio.

FIG. 2 is a characteristic diagram showing the influence of fluctuations in accelerator opening APO on throttle opening TVO and EGR valve opening EGR / V in an engine having an electronically controlled throttle device and EGR device.

FIG. 3 is a functional block diagram showing the configuration of the invention of claim 1.

FIG. 4 is a functional block diagram showing the configuration of the invention of claim 2;

FIG. 5 is a schematic configuration diagram of an engine to which an embodiment of the present invention is applied.

FIG. 6 is a flowchart showing the operation contents of the control system according to the first embodiment of the present invention.

FIG. 7 is a calculation block diagram of the control system according to the first embodiment.

FIG. 8 is an explanatory diagram of a control area of the first embodiment.

FIG. 9 is an explanatory diagram showing an effect of the first embodiment.

FIG. 10 is a flowchart showing the operation contents of the control system according to the second embodiment of the present invention.

FIG. 11 is a calculation block diagram of a control system according to the second embodiment.

FIG. 12 is an explanatory diagram showing an effect of the second embodiment.

[Explanation of symbols]

1 Accelerator position sensor 2 crank angle sensor 3 Air flow meter 4 engine 5 Water temperature sensor 6 Fuel injection valve 7 Spark plug 8 Intake passage 9 Throttle valve 10 Electronically controlled throttle device 11 Control unit 12 Exhaust passage 13 EGR passage 14 EGR valve 15 Electronically controlled EGR device 16 Air-fuel ratio sensor

Front page continuation (51) Int.Cl. ⁷ Identification code FI F02D 43/00 F02D 43/00 301N F02M 25/07 550 F02M 25/07 550F 550J 550R (58) Fields investigated (Int.Cl. ⁷ , DB) Name) F02D 41/00-45/00 F02D 21/08 F02M 25/07

Claims (8)

(57) [Claims] 1. A throttle control device for controlling the opening of a throttle valve so as to obtain a predetermined target throttle opening based on an engine operating condition including an accelerator opening and an engine speed, and an engine operating condition based on the engine operating condition. E for controlling the opening degree of the EGR valve so that a predetermined target EGR amount is achieved E
A control device for an engine including a GR control device, comprising: a target intake air amount calculation unit for calculating a target intake air amount equivalent value TTPST at a stoichiometric air-fuel ratio from an accelerator opening APO and an engine speed Ne; And a target equivalence ratio TFBYA00 from the engine revolution speed Ne, and a target equivalence ratio TFPST to the target equivalence ratio TFPST.
A second target intake amount equivalent value TTP calculated by dividing by 0
A target intake air amount calculation unit, a target EGR ratio calculation unit that calculates the target EGR ratio TEGR from the accelerator opening APO and a predetermined operating state detection value, and a target EGR amount TPEGR from the target intake air amount TTPST and the target EGR ratio TEGR And a target EGR amount calculation unit for setting the target EGR amount TTPEGR to the second target intake air amount equivalent value TT.
A target total working gas amount calculation unit that calculates the target total working gas amount TTPGAS0 by adding P, a target total working gas amount limit value calculation unit that calculates the target total working gas amount limit value GASLMT, and a target total working gas amount A total working gas amount comparison calculation unit for comparing TTPGAS0 with the target total working gas amount limit value GASLMT, and a target total working gas amount TTPGAS based on the comparison result.
A target EGR rate correction calculation unit that corrects the target EGR rate in the decreasing direction for a predetermined period when 0 is larger than the target total working gas amount limit value GASLMT, and the second target intake air amount equivalent value TTP or the target EGR amount TTP.
An engine control device provided with a control system having a target throttle opening TTVO of a throttle control device and a target opening calculation unit for calculating a target EGR valve opening TSTP of the EGR control device from EGR and a target total working gas amount TTPGAS0. 2. The target opening degree calculation unit is configured to set a target total working gas amount TT.
The total opening area TAGAS of the throttle valve and the EGR valve is calculated based on PGAS0 and the engine speed Ne, and the opening area TAAIR of the throttle valve and the opening area TAEGR of the EGR valve are calculated by the following formulas: TAAIR = TAGAS × TTP / TTPGAS0 TAEGR = TAGAS × TTPEGR / TTPGAS
0 based on the opening area TAAIR of the throttle valve, and the target EGR valve opening TS
TP is based on the opening area TAEGR for the EGR valve,
The engine control device according to claim 1, wherein the engine control device is configured to perform respective calculations. 3. A throttle control device for controlling the opening of a throttle valve so as to attain a predetermined target throttle opening based on an engine operating condition including an accelerator opening and an engine speed, and a predetermined controller based on the engine operating condition. Goal E
EG that controls the opening of the EGR valve so that the GR amount is achieved
An engine control device including an R control device, comprising: a target intake air amount calculation unit for calculating a target intake air amount equivalent value TTPST at a theoretical air-fuel ratio from an accelerator opening APO and an engine speed Ne; And a target equivalence ratio TFBYA00 from the engine revolution speed Ne, and a target equivalence ratio TFPST to the target equivalence ratio TFPST.
A second target intake amount equivalent value TTP calculated by dividing by 0
A target intake air amount calculation unit, a target EGR ratio calculation unit that calculates the target EGR ratio TEGR from the accelerator opening APO and a predetermined operating state detection value, and a target EGR amount TPEGR from the target intake air amount TTPST and the target EGR ratio TEGR And a target EGR amount calculation unit for setting the target EGR amount TTPEGR to the second target intake air amount equivalent value TT.
A target total working gas amount calculation unit that calculates the target total working gas amount TTPGAS0 by adding P, a target total working gas amount limit value calculation unit that calculates the target total working gas amount limit value GASLMT, and a target total working gas amount A total working gas amount comparison calculation unit for comparing TTPGAS0 with the target total working gas amount limit value GASLMT, and a second target total working gas amount TTPG based on the comparison result.
As AS, when the target total working gas amount TTPGAS0 exceeds the target total working gas amount limit value GASLMT, the target total working gas amount limit value GASLMT is set to the target total working gas amount T.
When TPGAS0 is less than or equal to the target total working gas amount limit value GASLMT, the second target total working gas amount setting calculation unit that sets the target total working gas amount TTPGAS0, and the second target intake air amount equivalent value TTP or target EGR amount TTP
From the EGR and the second target total working gas amount TTPGAS, the target throttle opening TTVO and EGR of the throttle control device are obtained.
An engine control device provided with a control system having a target opening calculation unit for calculating a target EGR valve opening TSTP of the control device. 4. The target opening calculation unit calculates the total opening area TAGAS of the throttle valve and the EGR valve based on the second target total working gas amount TTPGAS and the engine speed Ne, and also calculates the opening area TAAIR for the throttle valve. , EGR valve opening area TAEGR is calculated based on the following formulas: TAAIR = TAGAS × TTP / TTPGAS TAEGR = TAGAS × TTPEGA / TTPGAS, and the target throttle opening TTVO is calculated based on the throttle valve opening area TAAIR. Target EGR valve opening TS
TP is based on the opening area TAEGR for the EGR valve,
The engine control device according to claim 3, wherein the engine control device is configured to perform respective calculations. 5. The second target total working gas amount calculating unit is a target total working gas amount limit value GA of the target total working gas amount TTPGAS0.
The sum of the second target EGR amount obtained by subtracting the excess amount with respect to SLMT from the target EGR amount TTPEGR and the second target intake air amount equivalent value TTP is set as the second target total working gas amount TTPGAS. The engine control device according to claim 3, wherein: 6. The control system is a target total working gas amount TTPGAS.
Second target E obtained by subtracting an excess amount from the target total working gas amount limit value GASLMT of 0 from the target EGR amount TPEGR
When the GR amount becomes less than zero, the target equivalence ratio TFBY
The engine control device according to claim 5, further comprising a target equivalent ratio correction calculation unit that corrects A00. 7. The target equivalence ratio correction calculator calculates a target total working gas amount TTPGAS0 target total working gas amount limit value GASLM.
It is configured to correct the target equivalence ratio in the air-fuel ratio enrichment direction by a ratio to the second target total working gas amount TTPGAS that is less than or equal to zero of the second target EGR amount obtained by subtracting the excess amount with respect to T from the target EGR amount TPEGR. The engine control device according to claim 6, wherein: 8. The target total working gas amount computing unit determines a target EGR amount TPEGR by a conversion coefficient KQEG determined in accordance with an operating state including at least one of exhaust pressure and exhaust temperature.
4. The target total working gas amount TTPGAS0 is calculated using the target EGR amount fresh air conversion value TTPPEG corrected by R as the target EGR amount. Engine controller.