JPH11132049A - Supercharging pressure controller for internal combustion engine with egr controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain both of EGR control and supercharging pressure control. SOLUTION: In an internal combustion engine with EGR controller involving a supercharger which can control supercharging pressure arbitrarily, EGR amount is feedback-controlled to a target value based on a factor including intake air amount or a value in connection with it. The basic suppercharging pressure of the supercharger is set based on the rotational speed and load of an engine, corrected with a load charging rate and atmospheric pressure, and is controlled so as to be corrected supercharging pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to EGR control and supercharging pressure control of an internal combustion engine having an EGR control device and a supercharger capable of variably controlling a supercharging pressure.

[0002]

2. Description of the Related Art In an internal combustion engine, a part of exhaust gas is recirculated into intake air to raise a combustion temperature to thereby reduce NOx in exhaust gas.
It is effective to perform EGR (exhaust gas recirculation) to reduce (nitrogen oxides), especially in diesel engines.
This is an indispensable technology for exhaust gas purification, because there is no effective means for reducing exhaust gas.

[0003] On the other hand, in order to improve drivability and fuel efficiency, it is common to mount a supercharger on an engine, and a diesel engine having a small specific output per displacement has a high mounting ratio. In addition, in order to keep the efficiency of the supercharger high irrespective of the rotational load, in recent years, a variable nozzle turbo and a variable wastegate control mechanism capable of arbitrarily controlling the supercharging pressure have been put into practical use.

Hereinafter, a diesel engine will be described as an example. However, the effects of the present invention can be similarly obtained in a supercharging pressure control device for an internal combustion engine having an EGR control device in other types of internal combustion engines such as a gasoline engine. First, the fuel injection amount, the fuel injection timing, and the EGR control device, which are the main control items of the diesel engine, will be briefly described.

[0005] In general, in a diesel engine, the fuel injection amount and the injection timing supplied to the combustion chamber are controlled by a fuel injection pump that is driven to rotate in synchronization with engine rotation. For example, the fuel injection timing is controlled by operating a hydraulic timer provided in the fuel injection pump with the supply pressure from the feed pump to change the phase of the face cam.

The fuel injection amount is adjusted by controlling the end of pressure feeding by moving the control sleeve position by a control lever (accelerator). Also, E
Some GR devices control the opening of the EGR valve by adjusting the negative pressure of the negative pressure valve. The electromagnetic valve is controlled so that the opening of the EGR valve becomes the target valve opening detected by the lift sensor. By controlling the duty ratio.

[0007] Further, there is a type in which the position of the EGR valve is controlled by using a step motor. Since the opening of the EGR valve is uniquely determined by the number of steps with respect to the reference position of the step motor, there is no need for feedback by a lift sensor. . Therefore, the valve opening is controlled by giving the target number of steps of the step motor which becomes the target valve opening.

In general, when NOx is reduced by applying a large amount of EGR, the ignition delay period becomes longer, the combustion temperature decreases, the combustion ratio in the latter half of the expansion stroke increases, and the combustion atmosphere becomes oxygen-deficient. PM: Particulate
Matter) and other exhaust components (HC, CO) tend to deteriorate. Further, the trade-off relationship between NOx and PM is such that when the load is high or the EGR amount is large,
That is, it is known that the lower the excess air ratio becomes, the more remarkable it becomes. In order to simultaneously reduce NOx and PM in exhaust gas, E is extremely precisely adjusted according to the rotational load and the operating state.
It is necessary to control the GR amount.

Therefore, several methods for precisely controlling the amount of EGR have been devised. The following two types are typical. First, one method is to detect both the total amount of gas sucked in and the amount of air newly sucked in, respectively, and regard the difference between the two as the EGR amount, and determine the EGR amount as a target EGR rate (EGR amount / intake new air amount). This is a method of controlling the EGR amount so as to coincide with (air volume).

For example, as described in JP-A-57-18048, an air flow meter is provided to measure the amount of intake air, and a pressure sensor is provided downstream to measure the total gas amount. EGR is calculated by calculating the output of both
Some EGR valves are used to determine an EGR amount and control the EGR valve so as to match an EGR amount set for each operating condition. As a second method, there is a control method that considers the flow rate flowing through the EGR valve.
The most easily physically considered method is to consider the flow of the EGR gas as a primary incompressible fluid, measure the differential pressure before and after the EGR, and determine the EGR valve opening area where the target EGR amount can be obtained by hydrodynamics (Bernoulli's law). ).

This method is characterized in that the required change amount of the EGR valve opening area is obtained according to the difference between the target value and the actually measured value, so that the feedback gain can be physically obtained. EGR control methods employing this method include, for example, Japanese Patent Application Laid-Open No. 62-298654 and Japanese Patent Application Laid-Open
As described in Japanese Patent No. 858 or the like, a differential pressure sensor for detecting a differential pressure between the intake side and the exhaust side of the EGR valve is provided, and the differential pressure sensor matches a target differential pressure set according to the engine speed and load. Control of the EGR valve as described in
No. 048, etc., the EGR amount is adjusted by comparing the EGR amount measured by a sensor with a reference value so that the EGR amount can be precisely controlled in consideration of the variation in the characteristics of the EGR valve and the like. There is something to do.

On the other hand, there is a vehicle equipped with a variable nozzle turbo (VGT) or the like capable of arbitrarily controlling the supercharging pressure. Drivability and fuel efficiency can be improved by controlling the supercharging pressure in accordance with the operation range. .

[0013]

However, in order to achieve the strict emission regulations of today, a large amount of EGR is applied to reduce NOx, while improving the operability during acceleration and the supercharging pressure during low-speed operation. The conventional EG is used to reduce the exhaust gas by increasing the excess air ratio due to the increase and also to control the supercharging pressure to improve the output by improving the turbocharger efficiency during rated output operation.
When the supercharging pressure control is performed by the engine having the R control device, there are the following problems.

In an engine equipped with a supercharger and having an EGR device, EGR control also performs supercharging pressure control by releasing working gas from exhaust gas to intake air. For this reason,
In the case where there is an actuator that performs supercharging pressure control, if the control is performed using the same parameters (the intake air amount and the supercharging pressure), hunting occurs because neither target value is determined.

On the other hand, if control is performed with priority given to either of them, the accuracy of the EGR control is reduced or the capability of the supercharging pressure control device cannot be fully utilized. Considering the case where there is no supercharging pressure control, for example,
As described in JP-A-267361, the intake pressure is maintained at a constant pressure.
Even if the GR is controlled, the exhaust pressure fluctuates even if the intake pressure is kept constant, so that the EGR amount changes and the accuracy is inevitably deteriorated. It is also known that it is difficult to achieve compatibility with drivability, and when the EGR amount is controlled so that the supercharging pressure is detected so as to be kept constant, a surge occurs due to the influence of the feedback in a steady state.

The present invention has been made in view of such a conventional problem. The stability of the EGR control and the supercharging pressure control including the transient operation without adding a special device,
An object of the present invention is to provide a supercharging pressure control device for an internal combustion engine with an EGR control device, which ensures responsiveness and control accuracy.

[0017]

For this purpose, the invention according to claim 1 includes an EGR control device for recirculating a part of the exhaust gas into the intake air and a supercharger capable of variably controlling the supercharging pressure. In an internal combustion engine, a rotational speed and a load of the engine, an atmospheric pressure, an intake air amount or a related value thereof are detected, and the EGR is performed based on an element including the intake air amount or a related value thereof.
The control unit feedback-controls the EGR amount to a target value, sets the basic supercharging pressure of the supercharger based on the engine speed and the load, and changes the basic supercharging pressure to the atmospheric pressure and the change in the engine load. The supercharging pressure is corrected based on the ratio, and the corrected supercharging pressure is controlled.

According to the first aspect of the present invention, the EGR control is performed by controlling the EGR control device (EGR valve) such that the target EGR rate is obtained based on an element including the intake air amount or its related value. , The EGR amount is feedback-controlled to the target value, so that highly accurate EGR control can be performed even if the supercharging pressure is variably controlled.

On the other hand, the supercharging pressure control can avoid the occurrence of hunting with the EGR control without being based on the detected value of the intake air amount or the supercharging pressure, and is based on the engine speed and load. By setting the supercharging pressure, and further correcting the supercharging pressure based on the atmospheric pressure and the change rate of the load of the engine, it is possible to maximize the effect of the supercharging pressure control while satisfying the required value of the supercharging pressure. .

The reason why the EGR control is used as the feedback control is not only that the main purpose of the control is to reduce the exhaust gas, but also because there is no delay due to the inertia of the compressor / turbine or the like as compared with the supercharger. This also takes into consideration that feedback control of the control device generally has better responsiveness. According to a second aspect of the present invention, an internal combustion engine having an EGR control device that recirculates a part of exhaust gas into intake air and having a supercharger capable of variably controlling a supercharging pressure detects an engine rotation speed. Rotation speed detecting means, load detecting means for detecting the load of the engine, load change rate calculating means for calculating the change rate of the load of the engine, atmospheric pressure detecting means for detecting the atmospheric pressure, and the amount of intake air or Intake air amount related value detecting means for detecting a related value; EGR feedback control means for performing feedback control of an EGR rate of the EGR control device to a target value based on a detected intake air amount or an element including the related value; Basic supercharging pressure setting means for setting a basic supercharging pressure of the supercharger based on the detected engine speed and load, and the basic supercharging pressure of the engine calculated as the detected atmospheric pressure. Of the load A supercharging pressure correction means for correcting, based on the ratio, characterized in that the supercharger is configured include a boost pressure control means for controlling the boost pressure obtained by the correction.

According to the second aspect of the present invention, in the EGR control, the EGR feedback control means obtains the target EGR rate based on an element including the value detected by the means for detecting the intake air amount or its related value. EG
By controlling the R control device (EGR valve), the EGR
Since the amount is feedback-controlled to the target value, highly accurate EGR control can be performed even if the supercharging pressure is variably controlled.

On the other hand, in the supercharging pressure control, hunting can be avoided from the EGR control without being based on the detected value of the intake air amount or the supercharging pressure. The basic supercharging pressure is set based on the speed and the load, and the supercharging pressure correcting means corrects the supercharging pressure based on the atmospheric pressure and the change rate of the engine load. By controlling the pressure, the effect of the supercharging pressure control can be maximized while satisfying the required value of the supercharging pressure.

Further, the invention according to claim 3 is characterized in that the value related to the amount of intake air is an intake pressure. According to the third aspect of the invention, the EGR amount can be feedback-controlled to the target value based on the intake pressure instead of the intake air amount. The invention according to claim 4 is
The supercharger is a variable nozzle turbocharger.

According to the fourth aspect of the present invention, the supercharging pressure can be arbitrarily controlled by controlling the variable nozzle by the variable nozzle turbocharger. The invention according to claim 5 is characterized in that the supercharger is a wastegate type supercharger.

According to the invention of claim 5, the supercharging pressure can be arbitrarily controlled by controlling the flow rate of exhaust gas to the turbine by the wastegate type supercharger. Claim 6
The invention according to the invention is characterized in that the supercharger is an exhaust shutter type supercharger.

According to the present invention, the supercharging pressure can be arbitrarily controlled by controlling the throttle amount of the exhaust gas by the exhaust shutter type supercharger. Further, the invention according to claim 7 is an actuator control target value TBac of the boost pressure control.
t is the basic supercharging pressure T calculated from the engine speed and load.
B1 is calculated from the engine load correction value TB2 and the atmospheric pressure correction value Kpa by the following equation.

TBact = 100− (TB1 + TB2) × Kpa where the smaller the TBact, the higher the exhaust pressure and the supercharging pressure, and the larger the TBact, the lower the exhaust pressure and the supercharging pressure. According to the invention according to claim 7, by correcting the basic supercharging pressure with the load of the engine and the atmospheric pressure on the basis of the above equation, it is possible to perform good supercharging pressure control even during a change in the atmospheric pressure or during a transient operation. it can.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 shows the overall configuration of the embodiment. An electronically controlled fuel injection pump 1 pumps fuel to a fuel injection nozzle 2 mounted in a combustion chamber of the engine, and the fuel injection nozzle 2 injects and supplies fuel into the combustion chamber. An EGR passage 5 is connected to communicate the intake passage 3 and the exhaust passage 4, and an EGR valve 6 for controlling an EGR amount is connected to the EGR passage 5.
Is interposed. An air flow meter 7 for detecting a mass flow rate of the intake air and an intake air temperature sensor 8 for detecting an intake air temperature are mounted in the intake passage 3, and the downstream side thereof is supercharged by the exhaust pressure. A compressor of a supercharger (VGT) 9 equipped with a pressure control mechanism is interposed, and an intercooler 10 for cooling the intake air and increasing the charging efficiency is interposed downstream thereof. In the exhaust passage 4,
A turbine of the VGT 9 is interposed, and a supercharging pressure control actuator 11 that controls a supercharging pressure by controlling a variable nozzle of the turbine is mounted. An exhaust after-treatment device (not shown) may be mounted downstream of the exhaust passage.

Next, the control function will be described with reference to the block diagram shown in FIG. Engine speed, load, intake air volume,
The target EGR amount is set, the intake system pressure and the exhaust system pressure are calculated while detecting the intake air temperature and the EGR valve opening, and the EGR amount calculation and correction calculation are performed based on these results to perform the EGR valve opening. Calculate the target value. On the other hand, a basic control target value of the VGT is set based on each of the detected values, a load change is detected, a correction based on the load change is performed, and a VGT control target value is calculated after performing atmospheric pressure correction. .

Next, the configuration of the fuel injection device will be described with reference to FIG. First, the electronic control type (jerk type) fuel injection pump 1 will be described.
Is rotated by the drive shaft 22 to pre-press the fuel and supply the fuel to the pump chamber 23. The plunger 24 is rotated by the drive shaft 22, and reciprocates while rotating to pressurize and distribute fuel.

The control sleeve 25 adjusts the fuel injection amount by leaking the fuel pressurized by the plunger 24 into the high-pressure chamber. Rotary solenoid 26
Moves the position of the control sleeve 25 freely, and the control sleeve position sensor 27 detects the position of the control sleeve 25.

The fuel stop valve 28 stops the supply of fuel and stops the operation of the engine. The pump chamber 23 stores the fuel pressurized by the feed pump 21 and lubricates the inside of the pump. Timer piston 29 is a face cam
The fuel injection timing is controlled by changing the phase of the face cam 30 by engaging with and moving the position thereof.

The timing control valve 31 regulates the pressure of the timer high-pressure chamber by leaking high-pressure fuel for driving the timer piston 29 to the low-pressure chamber. As various sensors, a nozzle lift sensor 32 detects a valve opening timing of the fuel injection nozzle 2, a fuel temperature sensor 33 detects a temperature of fuel supplied to the fuel injection pump 1, and controls a control lever opening degree. The sensor 34 detects the accelerator opening, and the pump rotation speed sensor 35 detects the pump rotation speed.

Next, the configuration of the EGR device will be described with reference to FIG. Downstream of the air flow meter 7 in the intake passage 3, an intake throttle valve 101 for adjusting the pressure of the intake manifold is provided.
The opening degree of the intake throttle valve 101 is determined by a control negative pressure obtained by adjusting a negative pressure generated by a vacuum pump by two solenoid valves 103 and 104 based on a control signal from a control unit 102. It is controlled by a negative pressure actuator 105 that operates.

As described above, an EGR valve 6 which is driven by a step motor operated by a control signal from the control 102 to adjust the EGR amount is provided in the EGR passage 5 connecting the intake passage 3 and the exhaust passage 4. It is interposed. In addition to the method of detecting the intake air amount as shown in FIG. 5 and driving the EGR valve by the step motor, the negative pressure type E
The GR valve may be used, or the EGR amount may be controlled based on the intake air amount detected using a pressure sensor,
In the present invention, the configurations of the EGR valve and the sensor are not particularly limited.

Next, the configuration of the supercharging pressure control device will be described with reference to FIG. The nozzle vane 111 for adjusting the flow rate of the gas passing through the turbine is linked to an actuator ring 113 via a link mechanism 112. A pair of magnet valves 114,
115 supplies the air pressure obtained by adjusting the air tank and the negative pressure to the air cylinder 115, and controls the rotation amount of the actuator ring 113 by the air cylinder 115, whereby the turbine wheel of the nozzle vane 111 is rotated.
The angle with respect to 116 is controlled so that the supercharging pressure of the supercharger is controlled.

The supercharging pressure control device may be of a waste gate type or an exhaust shutter type other than the device having the variable nozzle mechanism shown in FIG. Is not particularly limited. Next, the operation of the present embodiment having the above configuration will be described with reference to flowcharts and block diagrams.

FIG. 7 is a flowchart for calculating the fuel injection amount Qsol. In step 1, the engine speed Ne and the control lever opening C / L representing the load on the engine are read. In step 2, the basic fuel injection amount Mqdrv is obtained from the engine speed Ne and the control lever opening C / L by searching the map shown in FIG.

In step 3, the basic fuel injection amount Mqd
In step 4 in which various corrections such as water temperature are made to rv to set the fuel injection amount to Qsol1, the maximum fuel injection amount is limited by searching the map shown in FIG.
The processing ends as sol. FIG. 10 is a flowchart for calculating the cylinder intake air amount Qac.

In step 11, the output voltage of the air flow meter 7 is read. In step 12, the amount of intake air per unit time is calculated from the output voltage by table conversion. In step 13, a value Qas0 obtained by performing a weighted average process on the intake air amount per unit time is obtained.

In step 14, the engine speed Ne is read. In step 15, the intake air amount Qac0 per cylinder is calculated from the weighted average processing value Qas0 of the intake air amount per unit time, the engine speed Ne and the constant KCON #. In step 16, n of the intake air amount Qac0
A delay process for the number of calculations is performed to calculate the intake air amount Qacn at the collector inlet.

In step 17, using the volume ratio Kvol and the volume efficiency equivalent value Kin, a delay process as shown is performed from the collector inlet intake air amount Qacn to obtain the cylinder intake air amount Qac, and the process ends. FIG. 11 shows a flow of a cycle process for adjusting the phases of the calculation for the detected values of the intake air temperature, the fuel injection amount, and the intake air amount.

In step 21, the cylinder intake air amount Qa
c, The fuel injection amount Qsol and the cylinder intake air temperature Tn are read. The cylinder intake air temperature Tn is calculated by, for example, an equation using an intake air temperature Ta, an EGR gas temperature Te, and a cylinder intake EGR gas amount Qec as shown. In step 22, cycle processing is performed on the cylinder intake air amount Qac, the fuel injection amount Qsol, and the cylinder intake air temperature Tn.
The cylinder intake air amount Qac and the cylinder intake air temperature Tn are subjected to delay processing by subtracting one from the number of cylinders, and the fuel injection amount Qsol is subjected to delay processing by subtracting two, and the processing is terminated with Qexh, Qfo, and Tno, respectively.

FIG. 12 is a block diagram for calculating the intake pressure. In step 31, the output voltage output from the air flow meter is converted into an intake air amount weight Qas0 per unit time. In step 32, the unit changes to the intake air amount Qacb per unit cycle. In block 33, in order to correct the output value of the air flow meter 7 with respect to the layout of the intake system, the air flow meter is corrected with respect to the engine speed and the weight of the intake air amount and output as the intake air amount Qac (same as FIG. 10).

In step 34, a value KINH2 corresponding to the basic volume efficiency of the intake system with respect to the engine speed and the intake air amount is searched. In step 35, the correction coefficient KI for the load
Search for NHQ. In step 36, the basic volume efficiency equivalent value KINH2 is multiplied by a correction coefficient KINHQ as shown in the figure, and the calculated value is output as the volume efficiency equivalent value Kin.

In step 37, the output voltage of the intake air temperature sensor is converted to the intake air temperature TINTBL. In step 38, the intake air temperature TINTBL is corrected by multiplying it by a correction coefficient KTMPI of the temperature rise with respect to the intake air pressure, and is output as the intake air temperature Tint. In Steps 39 and 40, the calculation shown in the simplified diagram of the thermodynamic formula is performed to calculate the intake pressure Pm.

FIG. 13 is a block diagram for calculating the exhaust pressure. In step 41, a basic exhaust temperature Texhi corresponding to the fuel injection amount is searched. In step 42, the basic exhaust gas temperature Texhi is corrected according to the swirl control valve opening to obtain a corrected basic exhaust gas temperature Ktexhi. In steps 43, 44, and 45, an exhaust temperature intake coefficient correction coefficient Ktmpe, an exhaust pressure correction coefficient Ktmpp, and an injection timing correction coefficient Ktmpit are respectively searched.

In step 46, these correction coefficients Ktmp
e, Ktmpp, and Ktmpit are converted to the corrected basic exhaust gas temperature Ktexhi.
To calculate an exhaust temperature equivalent value Tmpeh. Steps
In step 47, the cylinder intake air amount Qac measured earlier is cycle-processed by the difference between the intake stroke and the exhaust stroke, and is output as the working exhaust amount Qexh. In steps 48 and 49, the coefficients Kpexh # and Opexh # are adapted to the exhaust pressure experimentally as a function of the intake air amount Qexh, the exhaust temperature Tmpex, and the engine speed, and the exhaust pressure Pexh is calculated by performing the illustrated calculation. I do.

It should be noted that the intake pressure Pm and the exhaust pressure Pexh may be detected using pressure sensors.
FIG. 14 is a block diagram of the EGR control part. Steps
At 51, the intake pressure Pm calculated as described above (or detected by the intake pressure sensor) is read.

In step 52, the exhaust pressure Pexh calculated as described above (or detected by the exhaust pressure sensor) is read. In step 53, the EGR differential pressure ΔP is calculated by the following equation. Pm = Kpm # × Cpm + Opm # (see FIG. 12) (1) Pexh = Kpexh # × Cpexh + Opexh (see FIG. 13) (2) ΔP = Pexh−Pm (.) 3) In step 54, a target EGR rate Megr is retrieved from the engine speed Ne and the engine load (fuel injection amount) Qf.

In step 55, the output voltage of the air flow meter is read, and the intake air amount Qas0 is read. Steps
In 56, the target EGR flow rate Tqe is calculated by the following equation. Tqe = Megr × Qas0 . In step 57, the required EGR opening area Aevs
Is calculated.

Aevs = Tqe / (2ρΔP) ^{1/2 In} step 58, a flow coefficient a is retrieved from the engine speed Ne and the engine load (fuel injection amount) Qf. In step 59, the target EGR valve opening area is calculated by the following equation. Avps is a value equivalent to the fully open area of the EGR valve which is experimentally determined in advance, and is a value stored in the control unit as data.

[0053] Aev = a × Aevs {1 / (1-Aevs 2 / Avps 2} In step 60, the final target E from the target EGR valve opening area
A table search is performed for the EGR valve lift amount with respect to the GR valve opening area. In step 61, a control signal is output to a step motor that drives the EGR valve body so as to attain the target EGR valve lift amount.

FIG. 15 is a flowchart of the supercharging pressure control section. In step 71, the engine speed, load (fuel injection amount), and atmospheric pressure are read. In step 72, the amount of change in load is calculated. This will be described in detail in the subroutine of FIG. In step 73, an actuator instruction value TP1 set by the rotation speed and the load shown in FIG. 17 is searched.

In step 74, the actuator instruction value correction value TP2 for the load change amount shown in FIG. 18 is searched.
In step 75, the atmospheric pressure correction coefficient Kpa shown in FIG. 19 is searched. In step 76, the target signal TPact of the solenoid valve for controlling the pressure of the air cylinder for adjusting the opening degree of the nozzle vane is calculated by the equation shown. Note that TPact = 0 indicates that the opening area of the nozzle is the minimum, and TPact = 100 indicates that it is fully open.

FIG. 16 is a flowchart of a subroutine for calculating the load change amount dQf. In step 81, it is determined whether or not the counter value Cn = 0. Counter value C
When n is 0, the process proceeds to step 82, and when it is not 0, the process proceeds to step 84. In step 82, 1 is decremented from the number of cycles SETN for calculating dQf, and Qfn-setn ends without being changed.

In step 84, the current fuel injection amount Qf is read. In step 85, dQf is calculated by the equation shown. In step 86, Qfn-setn is updated to the current Qf, and the process ends. As described above, in the present invention, in the supercharging pressure control device, the intake air amount and the supercharging pressure are not basically detected, and the parameters are used for the EGR control.
The GR control accuracy is ensured to reduce the emission to the maximum, and the boost pressure control is basically an open control based on the target value of the actuator determined by the engine speed and load.
By using a configuration that compensates for changes in load and changes in atmospheric pressure, it is possible to maximize the effect of boost pressure control while satisfying the required boost pressure value, including during transient operation. EGR control and boost pressure control stability, responsiveness,
Control accuracy can be compatible (see FIG. 20).

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration and functions of the invention according to claim 2;

FIG. 2 is a diagram showing an overall configuration of an embodiment of the present invention.

FIG. 3 is a block diagram showing a control function of the embodiment.

FIG. 4 is a diagram showing a configuration of the fuel injection device.

FIG. 5 is a diagram showing a configuration of an EGR device.

FIG. 6 is a diagram showing a configuration of a supercharging pressure control device.

FIG. 7 is a flowchart of a routine for calculating a fuel injection amount.

FIG. 8 is a map for searching for a basic fuel injection amount.

FIG. 9 is also a map for searching for a maximum fuel injection amount.

FIG. 10 is a flowchart of a routine for calculating a cylinder intake air amount.

FIG. 11 is a flowchart of a cycle process for adjusting the phases of calculations for detected values of the intake air temperature, the fuel injection amount, and the intake air amount.

FIG. 12 is a block diagram for calculating the intake pressure.

FIG. 13 is a block diagram for calculating the exhaust pressure.

FIG. 14 is a block diagram of an EGR control part.

FIG. 15 is a flowchart of the supercharging pressure control unit.

FIG. 16 is a flowchart for calculating the amount of change in load.

FIG. 17 is a map for searching for an actuator instruction value that is also set by a rotation speed and a load.

FIG. 18 is a map for searching for an actuator instruction value correction value corresponding to a load change amount.

FIG. 19 is also a map for searching for an atmospheric pressure correction coefficient.

FIG. 20 is a time chart showing the effect of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fuel injection pump 2 Fuel injection nozzle 3 Intake passage 4 Exhaust passage 5 EGR passage 6 EGR control valve 7 Air flow meter 8 Intake temperature sensor 9 Turbocharger (VGT) 11 Supercharge pressure control actuator

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02D 23/00 F02M 25/07 550D 41/02 351 570P F02M 25/07 550 F02B 37/12 301A 570 301N

Claims (7)

[Claims] An internal combustion engine including an EGR control device that recirculates a part of exhaust gas into intake air and a supercharger capable of variably controlling a supercharging pressure, comprising: a rotation speed and a load of the engine; , An intake air amount or a related value thereof, and the E is determined based on an element including the intake air amount or the related value.
The EGR amount is feedback-controlled to a target value by the GR control device, and a basic supercharging pressure of the supercharger is set based on an engine speed and a load. A supercharging pressure control device for an internal combustion engine with an EGR control device, wherein the supercharging pressure is corrected based on a rate of change and is controlled to the corrected supercharging pressure. 2. An internal combustion engine having an EGR control device for recirculating a part of exhaust gas into intake air and having a supercharger capable of variably controlling a supercharging pressure, a rotational speed detecting means for detecting a rotational speed of the engine. Load detection means for detecting the load of the engine; load change rate calculation means for calculating the change rate of the load on the engine; atmospheric pressure detection means for detecting the atmospheric pressure; and detecting the intake air amount or its related value. Intake air amount related value detecting means; EGR feedback control means for performing feedback control of the EGR rate of the EGR control device to a target value based on the detected intake air amount or an element including the related value; Basic supercharging pressure setting means for setting a basic supercharging pressure of the supercharger based on a rotation speed and a load, and the basic supercharging pressure, a detected atmospheric pressure and a change rate of the calculated engine load. To And a supercharging pressure control means for controlling the supercharger to the corrected supercharging pressure. Supply pressure control device. 3. The supercharging pressure control device for an internal combustion engine with an EGR control device according to claim 1, wherein the value related to the intake air amount is an intake pressure. 4. The supercharging pressure of an internal combustion engine with an EGR control device according to claim 1, wherein the supercharger is a variable nozzle turbo type supercharger. Control device. 5. The supercharger according to claim 1, wherein the supercharger is a wastegate type supercharger.
4. A supercharging pressure control device for an internal combustion engine with an EGR control device according to (1). 6. The supercharging pressure control of an internal combustion engine with an EGR control device according to claim 1, wherein the supercharger is an exhaust shutter type supercharger. apparatus. 7. An actuator control target value TBact for the supercharging pressure control is calculated from a basic supercharging pressure TB1 calculated from an engine speed and a load, an engine load correction value TB2 and an atmospheric pressure correction value Kpa according to the following equation. The supercharging pressure control device for an internal combustion engine with an EGR control device according to any one of claims 1 to 6, wherein: TBact = 100− (TB1 + TB2) × Kpa where the smaller the TBact, the higher the exhaust pressure and the supercharging pressure, and the larger the TBact, the lower the exhaust pressure and the supercharging pressure.