JP3859010B2 - Turbocharger control device - Google Patents

Description

  The present invention relates to a turbocharger control device.

When both an EGR device (a device that recirculates part of the exhaust gas to the intake passage) and a supercharger are provided, from the viewpoint of supercharging pressure control, EGR control also physically plays a role of supercharging pressure control. Therefore, in the EGR operating range, the supercharger is controlled by open control, and when the EGR non-operating range is reached, the supercharger is feedback-controlled so that the actual supercharging pressure matches the target supercharging pressure. Various proposals have been made to devise supercharger control (see Patent Document 1).
JP-A-8-338256

  By the way, in the actuator that receives the supply of pressure according to the command value and drives the exhaust flow adjusting means of the turbocharger, it is necessary to take into account the difference in the change width of the supercharging pressure change with respect to the change in temperature and opening area. is there. To explain this, the relationship between the operating amount (= the operating state of the exhaust flow adjusting means) and the command value changes depending on the temperature of the actuator, but the same command value is not given to the actuator regardless of the temperature. The exhaust flow adjusting means cannot be adjusted to a desired state.

  Therefore, the present invention corrects the command value based on the temperature of the actuator, so that even when the relationship between the operation amount and the command value changes depending on the temperature of the actuator, the exhaust flow adjusting means is always used regardless of the temperature of the actuator. Is intended to be adjusted to a desired state.

According to a first aspect of the present invention, there is provided a turbocharger that supercharges air taken in by an engine (1) through an intake passage (3), and a flow rate of exhaust gas flowing into an exhaust turbine (52) of the turbocharger or Exhaust flow adjusting means (for example, variable nozzle 53) that adjusts the flow velocity, an actuator (54) that receives supply of pressure according to a command value and drives the exhaust flow adjusting means, and an operation target value of the exhaust flow adjusting means An operation target value setting means for setting the operation target value, a conversion means for converting the operation target value into the command value using a predetermined function, and a command value correction for correcting the command value to the actuator based on the temperature of the actuator Rutotomoni and means, comprising a detection means for detecting the engine rotational speed and the engine load, the command value correcting means, said post-completion engine warm-up on the basis of the detection result of said detecting means First temperature calculating means for calculating the temperature (Texhb) of the actuator and a predetermined delay process for the temperature (Texhb) calculated by the first temperature calculating means to calculate the current temperature (Texhdly) of the actuator A command value to the actuator based on the difference or ratio between the temperature (Texhb) calculated by the first temperature calculation unit and the temperature (Texhdly) calculated by the second temperature calculation unit. Correct .

  According to the first aspect of the invention, when using an actuator in which the relationship between the operating amount of the actuator (= the operating state of the exhaust flow adjusting means) and the command value varies depending on the temperature of the actuator, regardless of the temperature of the actuator The exhaust flow adjusting means can always be adjusted to a desired state.

According to the first invention, when the function for converting the operation target value to the command value is adapted in the state after the engine warm-up is completed, the temperature of the actuator after the engine warm-up is completed and the current temperature of the actuator The above effect can be obtained by a simple process such as correcting the command value by the difference or ratio.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a configuration for performing so-called low-temperature premixed combustion in which the heat generation pattern is single-stage combustion. This configuration itself is known from JP-A-8-86251.

  Now, the generation of NOx greatly depends on the combustion temperature, and lowering the combustion temperature is effective for reducing it. In low-temperature premixed combustion, in order to realize low-temperature combustion by reducing the oxygen concentration by EGR, the EGR passage 4 connecting the exhaust passage 2 and the collector portion 3a of the intake passage 3 is responsive to the control pressure from the pressure control valve 5. A diaphragm type EGR valve 6 is provided.

  The pressure control valve 5 is driven by a duty control signal from the control unit 41, and thereby obtains a predetermined EGR rate corresponding to operating conditions. For example, the EGR rate is set to a maximum of 100 percent in the low rotation speed and low load range, and the EGR rate is decreased as the rotation speed and load increase. Since the exhaust gas temperature rises on the high load side, if a large amount of EGR gas is recirculated, the effect of NOx reduction is reduced due to the rise of the intake air temperature, or the ignition delay period of the injected fuel is shortened and premixed combustion cannot be realized. For this reason, the EGR rate is gradually reduced.

  An EGR gas cooling device 7 is provided in the middle of the EGR passage 4. This is because of a water jacket 8 formed around the EGR passage 4 in which a part of the engine cooling water is circulated, and a flow rate control valve 9 provided at the cooling water inlet 7a and capable of adjusting the circulation amount of the cooling water. Thus, the degree of cooling of the EGR gas increases as the amount of circulation increases through the control valve 9 according to a command from the control unit 41.

  A swirl control valve (not shown) having a predetermined notch is provided in the intake passage near the intake port to promote combustion. When the swirl control valve is closed by the control unit 41 in the low rotation speed and low load range, the flow rate of the intake air sucked into the combustion chamber increases and swirls are generated in the combustion chamber.

  The combustion chamber is a large-diameter toroidal combustion chamber (not shown). This is because the piston cavity is formed in a cylindrical shape from the crown to the bottom of the piston without restricting the inlet, and at the center of the bottom, resistance is given to the swirl that swirls from the outside of the piston cavity in the latter half of the compression stroke. In order to further improve the mixing of air and fuel, a conical portion is formed. Due to the cylindrical piston cavity that does not restrict the inlet, the swirl generated by the swirl valve or the like is diffused from the inside of the piston cavity to the outside of the cavity as the piston descends during the combustion process. The swirl is sustained.

  The engine includes a common rail fuel injection device 10. The configuration of the common rail type fuel injection device 10 is also known (see the 13th internal combustion engine symposium symposium, pages 73-77) and is outlined with reference to FIG.

  The fuel injection device 10 mainly includes a fuel tank 11, a fuel supply passage 12, a supply pump 14, a common rail (accumulation chamber) 16, and a nozzle 17 provided for each cylinder. The fuel pressurized by the supply pump 14 is fuel. After being stored once in the pressure accumulation chamber 16 via the supply passage 15, the high pressure fuel in the pressure accumulation chamber 16 is distributed to the nozzles 17 corresponding to the number of cylinders.

  The nozzle 17 includes a needle valve 18, a nozzle chamber 19, a fuel supply passage 20 to the nozzle chamber 19, a retainer 21, a hydraulic piston 22, a return spring 23 that urges the needle valve 18 in the valve closing direction (downward in the figure), hydraulic pressure It comprises a fuel supply passage 24 to the piston 22 and a three-way valve (solenoid valve) 25 interposed in the passage 24. The passages 20 and 24 in the nozzle communicate with each other so that both the upper part of the hydraulic piston 22 and the nozzle chamber 19 have a high pressure. Since the pressure receiving area of the hydraulic piston 22 is larger than the pressure receiving area of the needle valve 18 when the three-way valve 25 to which the fuel is guided is OFF (ports A and B are connected and ports B and C are shut off), the needle valve 18 is Although in the seating state, when the three-way valve 25 is in the ON state (ports A and B are shut off and ports B and C are in communication), the fuel above the hydraulic piston 22 is returned to the fuel tank 11 via the return passage 28, oil The fuel pressure acting on the piston 22 is lowered. As a result, the needle valve 18 rises and fuel is injected from the nozzle hole at the tip of the nozzle. When the three-way valve 25 is returned to the OFF state again, the high pressure fuel in the pressure accumulating chamber 16 is guided to the hydraulic piston 22 and the fuel injection is completed. That is, if the three-way valve 25 is switched from OFF to ON, the fuel injection start time is adjusted by the ON time, and the fuel injection amount is adjusted by the ON time. The amount increases. 26 is a check valve and 27 is an orifice.

  The fuel injection device 10 further includes a pressure adjusting valve 31 in the passage 13 for returning the fuel discharged from the supply pump 14 in order to adjust the pressure in the pressure accumulation chamber. The adjustment valve 31 opens and closes the flow path of the passage 13 and adjusts the pressure in the pressure accumulation chamber by adjusting the amount of fuel discharged to the pressure accumulation chamber 16. The fuel injection rate varies depending on the fuel pressure (injection pressure) in the pressure accumulating chamber 16, and the fuel injection rate increases as the fuel pressure in the pressure accumulating chamber 16 increases.

  An accelerator opening sensor 33, a sensor 34 for detecting the engine speed and crank angle, a sensor 35 for cylinder discrimination, and a control unit 41 to which signals from the water temperature sensor 36 are input correspond to the engine speed and the accelerator opening. The target fuel injection amount and the target pressure of the pressure accumulating chamber 16 are calculated, and the fuel pressure in the pressure accumulating chamber 16 is fed back via the pressure regulating valve 31 so that the pressure accumulating chamber pressure detected by the pressure sensor 32 matches the target pressure. Control.

  Further, in addition to controlling the ON time of the three-way valve 25 in accordance with the calculated target fuel injection amount, by controlling the switching time of the three-way valve 25 to ON, a predetermined injection start time corresponding to the operating condition is obtained. I am doing so. For example, the fuel injection timing (injection start timing) is delayed to the piston top dead center (TDC) so that the ignition delay period of the injected fuel becomes longer on the low rotation speed and low load side with a high EGR rate. By this delay, the temperature in the combustion chamber at the ignition timing is lowered, and the premixed combustion ratio is increased, thereby suppressing the occurrence of smoke in the high EGR rate region. On the other hand, the injection timing is advanced as the rotational speed and load increase. This is because even if the ignition delay time is constant, the ignition delay crank angle (the value obtained by converting the ignition delay time into a crank angle) increases in proportion to the increase in the engine rotation speed. The injection timing is advanced in order to obtain the ignition timing.

  Returning to FIG. 1, a variable capacity turbocharger is provided in the exhaust passage 2 downstream of the opening of the EGR passage 4. This is a variable nozzle 53 (exhaust flow adjusting means) driven by an actuator 54 at the scroll inlet of the exhaust turbine 52. The control unit 41 allows the variable nozzle 53 to be supercharged from a low rotational speed range. In order to obtain pressure, the nozzle opening (inclined state) increases the flow rate of the exhaust gas introduced into the exhaust turbine 52 on the low rotational speed side, and the exhaust gas is introduced into the exhaust turbine 52 without resistance on the high rotational speed side to open the nozzle. Control (degrees fully open).

  The actuator 54 includes a diaphragm actuator 55 that drives the variable nozzle 53 in response to the control pressure, and a pressure control valve 56 that adjusts the control pressure to the actuator 55. The opening ratio of the variable nozzle 53 is described later. A duty control signal is generated so as to obtain the target opening ratio Rvnt obtained as described above, and this duty control signal is output to the pressure control valve 56.

  From the viewpoint of supercharging pressure control, EGR control also physically plays the role of supercharging pressure control. That is, the supercharging pressure also changes by changing the EGR amount. On the contrary, if the supercharging pressure is changed, the exhaust pressure changes, so the EGR amount also changes, and the supercharging pressure and the EGR amount cannot be controlled independently. In addition, there is a disturbance in control of each other. In order to ensure control accuracy when one is changed, it is necessary to re-adjust the other. However, after re-adapting the other, the other must be re-adapted. In the method, it is difficult to ensure the control accuracy at the time of transition.

  As described above, the supercharging pressure and the EGR amount affect each other. If the EGR amount is changed, it is difficult to properly adjust the nozzle opening degree. Therefore, in the control unit 41, the target intake air amount tQac is calculated according to the operating conditions, and the actual EGR which is a value obtained by delaying the target intake air amount tQac and the target EGR amount or the target EGR rate Megr. A target opening ratio Rvnt of the variable nozzle 53, which is an operation target value of the turbocharger, is set from the amount Qec and the actual GR rate Megrd.

Further, this target opening ratio Rvnt is converted into a command value to the pressure control valve 56. At this time, it is difficult to stabilize the target opening area without considering the hysteresis of the actuator 54. In order to deal with this, it is determined whether the target opening ratio Rvnt is increasing or decreasing. From this determination result, pressure control is performed in the increasing direction and decreasing direction even if the operation target value is the same. A command value basic value Dty is obtained by performing processing for differentiating the command value given to the valve 56. Calculate h.

In this case, since the relationship between the target opening ratio and the command value to the pressure actuator 54 is different depending on the temperature of the actuator 54, the exhaust temperature is predicted, and the thermal inertia component is estimated with respect to the predicted exhaust temperature Texhi and the predicted exhaust temperature Texhi. The command value basic value Dty is a difference from the value Texhdly subjected to the delay processing of Correct h.

  Further, when the advance process (feed forward) for compensating the dynamics of the actuator 54 is performed, it is necessary to resist the exhaust pressure only when the variable nozzle 53 is moved to the closed side. (Feed forward gain) Gkvnt and time constant equivalent value Tcvnt are different depending on whether the variable nozzle 53 is moved to the closing side or the opening side even if the operation target value is the same, and the variable nozzle 53 is moved to the closing side. When moving, the correction gain Gkvnt is increased and the time constant equivalent value Tcvnt is increased (because the time constant that is in the inverse relationship with the time constant equivalent value is reduced).

On the other hand, before the engine is warmed up, the operation of the actuator 54 is slow, and the actual opening ratio does not reach the target opening ratio Rvnt, or the movement becomes slow and the actual opening ratio reaches the target opening ratio Rvnt. Since there is a delay, in order to deal with this, control for confirming the operation of the actuator 54 is performed regardless of the target opening ratio. This operation confirmation control is, for example, reciprocating from the lower limit to the upper limit of the drive range of the actuator 54 (at this time, the variable nozzle 53 moves from the fully open position to the fully closed position). More specifically, since the command value for moving from the lower limit to the upper limit of the drive range of the actuator 54 varies depending on the engine speed, the control pattern Duty for instructing to move the lower limit to the upper limit of the drive range of the actuator 54 in a short cycle. Command value Duty according to pu and engine speed p A control command value Dtyvnt to the pressure control valve 56 is calculated from the product of ne.

  The contents of this control executed by the control unit 41 will be described according to the following flowchart. 3, 4, and 8 to 14, which will be described later, are prior application apparatuses (see Japanese Patent Laid-Open No. 10-288071), and FIGS. 1, 2, 5 to 7, and 15 to 64 are This is the same as that already proposed in another prior application device (see Japanese Patent Application No. 11-233892).

  First, FIG. 3 is for calculating the target fuel injection amount Qsol, and inputs a REF signal (crank angle reference position signal, every 180 degrees for a 4-cylinder engine and every 120 degrees for a 6-cylinder engine). Run every time.

  In steps 1 and 2, the engine rotational speed Ne and the accelerator opening degree Cl are read. In step 3, the basic fuel injection amount Mqdrv is calculated by searching a map having the contents shown in FIG. 4 based on these Ne and Cl. In step 4, the basic fuel injection amount Mqdrv is corrected to be increased by the engine coolant temperature or the like, and the corrected value is set as the target fuel injection amount Qsol.

  FIG. 5 is for calculating the opening area Aev of the EGR valve 6 and is executed for each input of the REF signal. In step 1, the target EGR amount Tqek is calculated. The calculation of Tqek will be described with reference to the flowchart of FIG.

  In FIG. 7 (subroutine of step 1 in FIG. 5), in steps 1 and 2, the intake air amount Qacn per cylinder and the target EGR rate Megr are calculated.

  Here, the calculation of Qacn will be described with reference to the flow of FIG. 8, and the calculation of Megr with reference to the flow of FIG.

  First, in FIG. 8, in step 1, the engine rotational speed Ne is read, and from this engine rotational speed Ne and the intake air amount Qas0 obtained from the air flow meter.

(Equation 1)
Qac0 = (Qas0 / Ne) × KCON #,
Where KCON # is a constant,
The intake air amount Qac0 per cylinder is calculated by the following equation.

  The air flow meter 39 (see FIG. 1) is provided in the intake passage 3 upstream of the compressor, and performs delay processing corresponding to the transport delay from the air flow meter 39 to the collector portion 3a. (Constant) The value of Qac0 before the rotation is obtained as the intake air amount Qacn per cylinder at the collector inlet 3a position. And in Step 4, for this Qacn

(Equation 2)
Qac = Qac _n-1 × (1-KIN × KVOL) + Qacn × KIN × KVOL,
Where KIN: volume efficiency equivalent value,
KVOL: VE / NC / VM,
VE: displacement,
NC: number of cylinders
VM: Intake system volume,
Qac _n-1 : Previous Qac,
Qac is calculated by the following equation (first-order lag equation) at the intake valve position per cylinder (this intake air amount is hereinafter abbreviated as “cylinder intake air amount”). This is to compensate for the dynamics from the collector inlet 3a to the intake valve.

  The detection of the intake air amount Qas0 on the right side of Equation 1 will be described with reference to the flowchart of FIG. The flow in FIG. 9 is executed every 4 ms.

In step 1, the output voltage Us of the air flow meter 39 is read, and in step 2, a voltage-flow rate conversion table having the contents shown in FIG. d is calculated. In step 3, this Qas0 The weighted average processing is performed on d, and the weighted average processing value is set as the intake air amount Qas0.

  Next, in FIG. 11, in step 1, the engine speed Ne, the target fuel injection amount Qsol, and the engine coolant temperature Tw are read. In step 2, the basic target EGR rate Megarb is calculated by searching a map having the contents shown in FIG. 12 from the engine speed Ne and the target fuel injection amount Qsol. In this case, the basic target EGR rate becomes larger as the engine is used more frequently, that is, at a lower rotation speed and a lower load (low injection amount), and is reduced at a high output at which smoke is likely to occur.

Next, in step 3, the water temperature correction coefficient Kegr for the basic target EGR rate is retrieved by searching a table having the contents shown in FIG. 13 from the cooling water temperature Tw. tw is calculated. In step 4, from the basic target EGR rate and the water temperature correction coefficient,

(Equation 3)
Megr = Megrb × Kegr tw
The target EGR rate Megr is calculated by the following formula.

  In step 5, it is determined whether or not the engine is in a complete explosion state. However, the determination of complete explosion will be described later with reference to the flowchart of FIG.

  In step 6, it is determined whether or not a complete explosion has occurred. If it is a complete explosion, the current process is terminated as is. If it is determined that the explosion is not complete, the target EGR rate Megr is set to 0 and the current process is terminated.

  Thereby, EGR control is performed after the complete explosion of the engine, and EGR is not performed before the complete explosion in order to ensure stable startability.

  FIG. 14 is used to determine the complete explosion of the engine. In step 1, the engine rotation speed Ne is read, and the engine rotation speed Ne is compared with the complete explosion determination slice level NRPMK corresponding to the complete explosion rotation speed in step 2. When Ne is larger, it is determined that the explosion is complete, and the process proceeds to Step 3. Here, the counter Tmrkb is compared with the predetermined time TMRKBP, and when the counter Tmrkb is larger than the predetermined time, the process proceeds to step 4 and the process is terminated as it is completely exploded.

  On the other hand, when Ne is smaller in step 2, the process proceeds to step 6, the counter Tmrkb is cleared, and the process is terminated in step 7 assuming that the complete explosion state is not reached. Further, even if it is larger than Ne in Step 2, if the counter Tmrkb is smaller than the predetermined time in Step 3, the counter is incremented in Step 5 and it is determined that the explosion is not complete.

  Thus, it is determined that the explosion has been completed when the engine speed is equal to or higher than a predetermined value (for example, 400 rpm) and this state is continued for a predetermined time.

  When the calculation of the cylinder intake air amount Qacn in FIG. 8 and the target EGR rate Megr in FIG. 11 are completed in this way, the process returns to step 3 in FIG.

(Equation 4)
Mqec = Qacn × Megr
The required EGR amount Mqec is calculated by the following equation.

  In step 4, KIN × KVOL is used as a weighted average coefficient for this Mqec.

(Equation 5)
Rqec = Mqec × KIN × KVOL + Rqec _n−1 × (1−KIN × KVOL),
Where KIN: volume efficiency equivalent value,
KVOL: VE / NC / VM,
VE: displacement,
NC: number of cylinders
VM: Intake system volume,
Rqec _n-1 : last intermediate processing value,
The intermediate processing value (weighted average value) Rqec is calculated by the following equation, and in step 5 using this Rqec and the required EGR amount Mqec

(Equation 6)
Tqec = Mqec × GKQEC + Rqec _n−1 × (1-GKQEC),
However, GKQEC: Lead correction gain,
The target EGR amount Tqec per cylinder is calculated by performing advance correction according to the following equation. Since there is a delay in the intake system with respect to the required value (that is, a delay corresponding to the capacity of the EGR valve 6 → the collector portion 3a → the intake manifold → the intake valve), Steps 4 and 5 perform advance processing for this delay. .

  In step 6

(Equation 7)
Tqek = Tqec × (Ne / KCON #) / Kqac00,
However, Kqac00: EGR amount feedback correction coefficient,
KCON #: constant,
Unit conversion (per cylinder → per unit time) is performed by the following formula to obtain the target EGR amount Tqek. The calculation of the EGR amount feedback correction coefficient Kqac00 will be described later (see FIG. 54).

  When the calculation of the target EGR amount Tqek is completed in this manner, the flow returns to step 2 in FIG. From this EGR flow velocity Cqe and the target EGR amount Tqek

(Equation 8)
Aev = Tqek / Cqe
The EGR valve opening area Aev is calculated by the following formula. The calculation of the EGR flow rate Cqe will be described later (see FIG. 63).

  The EGR valve opening area Aev obtained in this way is converted into a lift amount of the EGR valve 6 by searching a table having the contents shown in FIG. 6 in a flow (not shown) so that the EGR valve lift amount becomes this EGR valve lift amount. A duty control signal is generated for the pressure control valve 5, and this duty control signal is output to the pressure control valve 5.

  Next, FIG. 15 and FIG. 16 are for calculating the control command duty value Dtyvnt given to the pressure control valve 56 for driving the turbocharger, and are executed at regular time intervals (for example, every 10 ms).

  15 is the first embodiment, and FIG. 16 is the second embodiment, the two embodiments have different parameters used to calculate the target opening ratio Rvnt of the variable nozzle 53 (the first embodiment of FIG. 15). The target opening ratio Rvnt of the variable nozzle 53 is calculated based on the actual EGR amount Qec, and in the second embodiment of FIG. 16 based on the actual EGR rate Megrd).

  15 and 16 are main routines, and a large flow of control follows the steps shown in the figure, and subroutines are prepared for the processing of each step. Therefore, the following description will focus on subroutines.

  FIG. 17 (subroutine of step 1 in FIGS. 15 and 16) is for calculating the actual EGR rate, and is executed every 10 ms. In step 1, the target EGR rate Megr (which has already been obtained in FIG. 11) is read, and in step 2, a time constant equivalent value Kkin corresponding to the collector capacity is calculated. The calculation of Kkin will be described with reference to the flowchart of FIG.

In FIG. 18 (subroutine of step 2 in FIG. 17), in step 1, engine rotational speed Ne, target fuel injection amount Qsol, and a previous value of actual EGR rate to be described later, Megrd _n-1 [%], are read. And Qsol is used to calculate a volume efficiency equivalent basic value Kinb by searching a map having the contents shown in FIG.

(Equation 9)
Kin = Kinb × 1 / (1 + Megrd _n−1 / 100)
The volume efficiency equivalent value Kin is calculated by the following formula. This is because the volumetric efficiency is reduced by EGR, so that correction is made accordingly.

  A value obtained by multiplying Kin thus obtained by KVOL (see Step 4 in FIG. 8), which is a constant corresponding to the ratio of the intake system volume and the cylinder volume in Step 4, is set as a time constant equivalent value Kkin corresponding to the collector capacity. Calculate.

  When the calculation of Kkin is completed in this way, the process returns to Step 3 in FIG. 17, and using this Kkin and the target EGR rate Megr,

(Equation 10)
Megrd = Megr × Kkin × Ne × KE2 #
+ Megrd _n-1 × (1-Kkin × Ne × KE2 #),
However, Kkin: Kin × KVOL #,
KE2 #: constant,
Megrd _n-1 : last Megrd,
The EGR rate Megrd at the intake valve position is calculated by simultaneously performing delay processing and unit conversion (per cylinder → per unit time) using the following equation. Ne × KE2 # on the right side of Equation 10 is a value for unit conversion. Since this Megrd responds to the target EGR rate Megr with a first-order lag, this Megrd is hereinafter referred to as “actual EGR rate”.

  FIG. 20 (subroutine of step 2 in FIGS. 15 and 16) is for calculating the target intake air amount tQac. In step 1, the engine speed Ne, the actual EGR rate Megrd, and the target fuel injection amount Qsol are read, and in step 2, Megrd is compared with a predetermined value MEGLV #.

  Here, the predetermined value MEGLV # is a value (for example, 0.5) for determining whether or not the EGR is operated. When Megrd> MEGRLV #, it is determined that the EGR is in the operation range, and steps 3, 4 and On the other hand, if Megrd ≦ MEGRLV #, on the other hand, it is determined that the EGR is in the non-operating range, and the process proceeds to step 6. MEGLV # is not 0 in response to a request for handling the same amount of EGR as when EGR is not performed.

  If it is within the EGR operating range, the target intake air amount basic value tQacb is calculated in step 3 by searching a map having the contents shown in FIG. 21 from the engine speed Ne and the actual EGR rate Megard. If the engine speed is constant, the target intake air amount is increased as the actual EGR rate is larger as shown in FIG.

  In step 4, the correction coefficient ktQac of the target intake air amount is calculated by searching a map having the contents shown in FIG. 22 from Ne and Qsol, and a value obtained by multiplying the basic value of the target intake air amount by the correction coefficient is calculated. Calculated as the target intake air amount tQac. The correction coefficient ktQac is for responding to a request for changing the target intake air amount according to the operating conditions (Ne, Qsol).

  On the other hand, when it is in the non-operating region of EGR, the process proceeds to step 6 and the target intake air amount tQac is calculated by searching a map having the contents of FIG. 23 from Ne and Qsol, for example.

  FIG. 24 (subroutine of step 3 in FIG. 15) is for calculating the actual EGR amount. In step 1, the intake air amount Qacn per cylinder at the collector inlet 3a position (already obtained in step 3 of FIG. 8), the target EGR rate Megr, and the time constant equivalent value Kkin for the collector capacity are read. Of these, from Qacn and Megr

(Equation 11)
Qec0 = Qacn × Megr
The EGR amount Qec0 per cylinder at the collector inlet 3a position is calculated by the following equation, and in step 3, using this Qec0 and Kkin,

(Equation 12)
Qec = Qec0 × Kkin × Ne × KE #
+ Qec _n-1 × (1-Kkin × Ne × KE #),
However, Kkin: Kin × KVOL,
KE #: constant,
Qec _n-1 : Previous Qec,
In the same manner as in the above formula 10, delay processing and unit conversion (per cylinder → per unit time) are simultaneously performed to calculate the cylinder intake EGR amount Qec. Ne × KE # on the right side of Equation 12 is a value for unit conversion. Since this Qec responds to the target EGR amount Tqek with a first-order delay, this Qec is hereinafter referred to as “actual EGR amount”. The above Qac that responds to the target intake air amount tQac with a first-order delay is hereinafter referred to as “actual intake air amount”.

  FIG. 25 (subroutine of step 4 in FIG. 15) and FIG. 27 (subroutine of step 3 in FIG. 16) are for calculating the target opening ratio Rvnt of the variable nozzle 53 (FIG. 25 is the first embodiment, FIG. 27 is the second embodiment).

  Here, the opening ratio of the variable nozzle 53 is the ratio of the current nozzle area to the nozzle area when the variable nozzle 53 is fully opened. Therefore, the opening ratio is 100% when the variable nozzle 53 is fully opened, and the opening ratio is 0% when the variable nozzle 53 is fully closed. The reason for adopting the opening ratio is to provide versatility (a value not related to the turbocharger capacity). Of course, the opening area of the variable nozzle may be adopted.

  In addition, since the turbocharger of the embodiment is a type in which the supercharging pressure is the smallest when fully opened and the supercharging pressure is highest when fully closed, the supercharging pressure becomes higher as the opening ratio is smaller.

  First, referring to FIG. 25 of the first embodiment, in step 1, the target intake air amount tQac, the actual EGR amount Qec, the engine speed Ne, and the target fuel injection amount Qsol are read.

  In steps 2 and 3,

(Equation 13)
tQas0 = (tQac + Qsol × QFGAN #) × Ne / KCON #
Qes0 = (Qec + Qsol × QFGAN #) × Ne / KCON #,
Where QFGAN #: gain,
KCON #: constant,
In order to set the target opening ratio in the same manner as the intake air amount equivalent value tQas0 (hereinafter referred to as “set intake air amount equivalent value”) for setting the target opening ratio An EGR amount equivalent value Qes0 (hereinafter, this EGR amount equivalent value is referred to as a “set EGR amount equivalent value”) is calculated. In Equation 13, Qsol × QFGAN # is added to tQac and Qec so that load correction can be performed for the set intake air amount equivalent value and the set EGR amount equivalent value, and the sensitivity is gain QFGAN #. The adjustment is done with Further, Ne / KCON # is a value for converting into an intake air amount and an EGR amount per unit time.

  In step 4, from the set intake air amount equivalent value tQas0 and the set EGR amount equivalent value tQes0 thus determined, for example, a target opening ratio Rvnt of the variable nozzle 53 is set by searching a map having the contents shown in FIG.

  On the other hand, in FIG. 27 of the second embodiment, the target intake air amount tQac, the actual EGR rate Megrd, the engine rotational speed Ne, and the target fuel injection amount Qsol are read in Step 1, and in Step 2, The set intake air amount equivalent value tQas0 is calculated from the upper equation, and the target of the variable nozzle 53 is searched by searching, for example, a map containing FIG. 28 in step 3 from the set intake air amount equivalent value tQas0 and the actual EGR rate Megard. An opening ratio Rvnt is set.

  The characteristics shown in FIGS. 26 and 28 are set with emphasis on fuel consumption. However, since the difference from the exhaust-oriented setting example described later is only a specific numerical value, the characteristics common to both will be described first, and then the difference between the two will be described. The characteristic of FIG. 28 is different from FIG. 26 in the vertical axis (in FIG. 26, the inclination from the origin indicates the EGR rate), but basically does not change from FIG. .

  As shown in FIG. 26, in the region on the right side where the set intake air amount equivalent value tQas0 is large, the target opening ratio is reduced as the set EGR amount equivalent value Qes0 increases. This is for the following reason. As the EGR amount increases, the amount of fresh air decreases, and smoke is generated when the air-fuel ratio leans to the rich side. Therefore, as the EGR amount increases, it is necessary to decrease the target opening ratio and increase the supercharging pressure.

  On the other hand, the supercharging effect is not obtained so much in the left region where tQas0 is small. In this region, the target opening ratio is reduced as tQas0 becomes smaller. This is for the following reason. In this region, if the target opening ratio is increased, the exhaust pressure is unlikely to rise, so that this is to be avoided, and for full acceleration, it is better that the opening ratio is small at the initial stage. In this way, the characteristics of FIG. 26 are basically determined from two different requirements. For this reason, the change in the target opening ratio differs depending on whether the change in the target intake air amount is small or large.

  Now, the tendency of the target opening ratio represented in FIG. 26 is common to fuel efficiency and exhaust gas, and the difference between them is a specific numerical value. In the figure, the numerical value at the position “small” is the minimum value at which the turbocharger operates efficiently, and is the same in both the fuel efficiency-oriented setting example and the exhaust-oriented setting example, and is about 20, for example. On the other hand, the numerical value of the position with “large” is different between the two, and is about 60 in the setting example with emphasis on fuel consumption and about 30 in the setting example with emphasis on exhaust.

  Note that the setting of the target opening ratio is not limited to the above. In the first embodiment, the target opening ratio is set from the set intake air amount equivalent value tQas0 and the set EGR amount equivalent value Qes0. Instead, it is set from the target intake air amount tQac and the actual EGR amount Qec. It doesn't matter. Further, instead of this, the target intake air amount tQac and the target EGR amount (Qec0) may be set. Similarly, in the second embodiment, the target opening ratio is set from the set intake air amount equivalent value tQas0 and the actual EGR rate Megard, but instead, it is set from the target intake air amount tQac and the actual EGR rate Megard. It doesn't matter. Further, instead of this, the target intake air amount tQac and the target EGR rate Megr may be set.

  29 (subroutine of step 5 in FIG. 15 and step 4 in FIG. 16), the variable nozzle drive actuator 54 (pressure control valve 56 and diaphragm actuator 55) is obtained with respect to the target opening ratio Rvnt obtained as described above. Is performed in order to compensate for the dynamics. This is because, when the actuator of the variable nozzle 53 is an actuator that is driven by receiving pressure supplied according to the command value, there is a response delay that cannot be ignored, unlike the case of a step motor.

In step 1, the target opening ratio Rvnt is read, and this Rvnt and the previous predicted opening ratio Cavnt _n-1 are compared in step 2. Here, the expected opening ratio Cavnt is a weighted average value of the target opening ratio Rvnt (see step 10), as will be described later.

If Rvnt> Cavnt _n-1 (when the variable nozzle 53 is moved to the opening side), the process proceeds to Steps 3 and 4 and proceeds to a predetermined value GKVNTO # to advance the correction gain Gkvnt and the predetermined value TCVNTO # to a time constant equivalent value Tcvnt. On the other hand, when Rvnt <Cavnt _n−1 (when the variable nozzle 53 is moved to the closing side), the process proceeds to Steps 6 and 7 to advance the predetermined value GKVNTC # to the correction gain Gkvnt, The predetermined value TCVNTC # is set as the time constant equivalent value Tcvnt. If Rvnt and Cavnt _n-1 are the same, the process proceeds to Steps 8 and 9, and the previous advance correction gain and time constant equivalent value are maintained.

  The advance correction gain Gkvnt and the time constant equivalent value Tcvnt are made different between when the variable nozzle 53 is moved to the open side and when it is moved to the close side, and GKVNTO # <GKVNTC # and TCVNTO # <TCVNTC #. This is because when the variable nozzle 53 is moved to the closing side, it is necessary to resist the exhaust pressure, so that the gain Gkvnt is increased and the time constant is decreased (corresponding to a time constant that is inversely related to the time constant). This is because the value Tcvnt needs to be increased).

  In step 10, using the time constant equivalent value Tcvnt and the target opening ratio Rvnt thus obtained,

(Equation 14)
Cavnt = Rvnt × Tcvnt + Cavnt _n−1 × (1−Tcvnt),
However, Cavnt _n-1 : last Cavnt,
The expected opening ratio Cavnt is calculated by the following formula, and from this value and the target opening ratio Rvnt, in step 11,

(Equation 15)
Avnt f = Gkvnt × Rvnt− (Gkvnt−1) × Cavnt _n−1 ,
However, Cavnt _n-1 : last Cavnt,
The feed forward amount Avnt of the target aperture ratio f is calculated. The advance process itself in steps 10 and 11 is basically the same as the advance process shown in steps 4 and 5 in FIG.

30 (subroutines of step 6 in FIG. 15 and step 5 in FIG. 16) is a feedback amount Avnt of the target opening ratio. This is for calculating fb. In step 1, the target intake air amount tQac, the target EGR rate Megr, the engine speed Ne, the target fuel injection amount Qsol, and the actual intake air amount Qac are read. In step 2, the target EGR rate Megr and a predetermined value MEGLV # are compared.

  When Megr ≧ MEGRLV # (in the EGR operating range), in step 4

(Equation 16)
dQac = tQac / Qac-1
The error ratio dQac from the target intake air amount is calculated by the following equation. The value of dQac is centered on 0, and becomes positive when Qac as an actual value is smaller than tQac as a target value, and conversely becomes negative when Qac is larger than tQac.

  On the other hand, when Megr <MEGRLV # (when the EGR is in the non-operating range), the routine proceeds to step 3 where the error ratio dQac = 0 (that is, feedback is prohibited).

In step 5, a feedback gain correction coefficient Kh is calculated by searching a predetermined map from Ne and Qsol, and this value is converted into each constant (proportional constant KPB #, integral constant KIB #, differential constant KDB #) in step 6. The feedback gains Kp, Ki, and Kd are calculated by multiplying them, and the feedback amount Avnt of the target opening ratio is calculated using these values. In step 7, fb is calculated. This feedback amount calculation method is a well-known PID process.

  The correction coefficient Kh is introduced in response to a change in the appropriate feedback gain depending on the operating conditions (Ne, Qsol), and increases as the load and the rotational speed increase.

FIG. 31 (subroutines of step 7 in FIG. 15 and step 6 in FIG. 16) is for performing linearization processing on the target aperture ratio. Feed forward amount Avnt of target opening ratio in step 1 f and feedback amount Avnt A value obtained by reading fb and adding the two in step 2 is calculated as a command opening ratio Avnt. In step 3, the command opening ratio linearization processing value Ratdty is set by searching, for example, a table (linearization table) having the contents shown in FIG. 32 from the command opening ratio Avnt.

  This linearization processing is necessary when the command signal to the actuator that drives the turbocharger has non-linear characteristics with respect to the opening ratio (or opening area) as shown in FIG. For example, as shown in FIG. 33, even if the change amount of the air amount (supercharging pressure) is the same, the change amount of the opening area is greatly different from dA0 and dA1 in the region where the air amount is small and the region where the air amount is large ( (Without EGR) Furthermore, the change width of the opening area varies depending on the presence or absence of EGR ("w / o EGR" indicates no EGR and "w / EGR" indicates that EGR is present) in the figure. Therefore, the target intake air amount (supercharging pressure) cannot be obtained if the same feedback gain is used regardless of the operating conditions. Therefore, in order to facilitate the adaptation of the feedback gain, the feedback gain correction coefficient Kh corresponding to the operating condition is introduced as described above.

  FIG. 34 (subroutines of step 8 of FIG. 15 and step 7 of FIG. 16) is for setting a control command value Dtyvnt which is an ON duty value (hereinafter simply referred to as “duty value”) applied to the pressure control valve 56. It is. First, at step 1, the engine speed Ne, the target fuel injection amount Qsol, the command opening ratio linearization processing value Ratdty, the time constant equivalent value Tcvnt, and the water temperature Tw are read.

  In step 2, the duty selection signal flag is set. This flag setting will be described with reference to the flowchart of FIG. In FIG. 35, the command opening ratio Avnt and the time constant equivalent value Tcvnt are read in Step 1, and from these, in Step 2,

(Equation 17)
Adlyvnt = Avnt × Tcvnt
+ Adlyvnt _n-1 × (1-Tcvnt),
However, Adlyvnt _n-1 : previous Adlyvnt,
The expected opening ratio Adlyvnt is calculated by performing a delay process according to the following equation, and this value is compared with Adlyvnt _nM which is the previous value of M (where M is a constant) times of the previous predicted opening ratio in Step 3.

When Adlyvnt ≧ Adlyvnt _nM (in an increasing tendency or steady state), the operation direction command flag fvnt = 1 is set in step 4 in order to indicate that it is in an increasing tendency or steady state, and otherwise, the operation direction is determined in step 5 The command flag fvnt = 0. In step 6, Adlyvnt and Adlyvnt _nM are compared in order to separate the case of increasing tendency from the steady state. If Adlyvnt = Adlyvnt _nM , the duty holding flag fvnt2 = 1 is set in step 7, otherwise step 8, the duty hold flag fvnt2 = 0.

When the setting of the two flags fvnt and fvnt2 is completed in this way, the process returns to step 3 in FIG. 34 to change the duty value temperature correction amount Dty. t is calculated. This calculation will be described with reference to the flowchart of FIG.

In FIG. 36, the engine rotational speed Ne, the target fuel injection amount Qsol, and the water temperature Tw are read in Step 1, and the basic exhaust temperature Texhb is retrieved from Ne and Qsol by searching, for example, a map containing FIG. Is calculated. Here, Texhb is the exhaust temperature after completion of warm-up. On the other hand, if it is in the middle of warming up, it differs from the exhaust temperature after the completion of warming up. Therefore, in step 3, for example, by searching a table having the contents shown in FIG. Ktexh tw is calculated, and the value obtained by multiplying this value by the basic exhaust temperature in step 4 is calculated as the exhaust temperature Texhi.

  In step 5, from this exhaust temperature Texhi

(Equation 18)
Texhdly = Texhi × KEXH #
+ Texhdly _n-1 × (1-KEXH #),
Where KEXH #: constant,
Texhdly _n-1 : last Texhdly,
A value obtained by performing the delay process according to the equation is calculated as the actual exhaust temperature Texhdly. This is to perform a delay process for the thermal inertia.

In step 6, the difference dTexh between the basic exhaust temperature Texhb and the actual exhaust temperature Texhdly is calculated, and in step 7, for example, a table having the contents shown in FIG. t is calculated. Steps 6 and 7 are maps (Duty used for hysteresis) described later. h p, Duty h n, Duty l p, Duty l In consideration of setting the map of n) after completion of warm-up, a correction amount corresponding to the difference from that state (that is, dTexh) is given. The temperature correction amount Dty The correction by t is a process required when using a turbocharger driving actuator having temperature characteristics depending on the ambient temperature (see FIG. 40).

In this way, the temperature correction amount Dty When the calculation of t is completed, the process returns to step 4 in FIG.

Steps 4 to 9 in FIG. 34 perform hysteresis processing. This process will be described with reference to FIG. 45. This is because the upper characteristic (Duty) is set when the command opening ratio linearization process value Ratdty tends to increase. l p is the command signal when the variable nozzle is fully open, Duty h When the command opening ratio linearization processing value Ratdty tends to decrease while p is used as a command signal when p is a variable nozzle fully closed, another lower characteristic (Duty) is used. l n is the command signal when the variable nozzle is fully open, Duty The h n is to use a linear characteristic) to the command signal of the variable nozzle is fully closed. Note that there is a region where the two characteristics are reversed in a region where the Ratdty is close to 1, but this region is not actually used.

  More specifically, the actuator 54 has an effective duty range (the vertical width of the characteristic shown in FIG. 45 and the vertical position of the characteristic shown in FIG. 40) depending on the operating conditions (engine speed, engine load) and actuator temperature. Change). Therefore, the direction of increase / decrease of the target opening ratio is taken into consideration so that the Ratdty as the target opening ratio matches the actual opening ratio, and further, it corresponds to the change of the effective operating range of the duty value due to the change of the actuator temperature. .

Returning to FIG. 34, the flag fvnt1 is checked in step 4. When fvnt = 1 (that is, when the opening ratio tends to increase or is in a steady state), the process proceeds to steps 5 and 6, for example, a map (Duty) having the contents shown in FIG. h p map) and a map (Duty) containing the contents of FIG. l Duty value Duty when variable nozzle is fully closed by searching (p map) h and duty value Duty when variable nozzle is fully open Set l respectively. On the other hand, when fvnt = 0 (that is, when the opening ratio tends to decrease), the process proceeds to steps 7 and 8, for example, a map (Duty) having the contents shown in FIG. h n map) and a map (Duty) with the contents shown in FIG. l n map) by searching the variable nozzle fully closed duty value Duty h and duty value Duty when variable nozzle is fully open Set l respectively.

Duty value Duty when variable nozzle is fully closed thus set h, Duty value Duty when variable nozzle is fully open In step 9, using l and the command opening ratio linearization processing value Ratdty,

(Equation 19)
Dty h = (Duty h-Duty l) x Ratdty
+ Duty l + Dty t
The command duty value basic value Dty is calculated by performing linear interpolation calculation using the equation Calculate h. That is, the characteristics of the straight line used for the linear interpolation calculation are changed between when the command opening ratio linearization processing value is increasing or in a steady state and when the command opening ratio linearization processing value is decreasing ( By performing hysteresis processing), even when the command opening ratio linearization processing value is the same, the command opening ratio linearization processing value is in a tendency of increasing (or steady state) than the command opening ratio linearization processing value is decreasing. Duty value basic value Dty h increases.

In step 10, another flag fvnt2 is seen. When fvnt2 = 1 (ie, there is no change in the command opening ratio linearization processing value), the routine proceeds to step 11 where Dtyvnt _n−1 , which is the previous control command duty value (described later), is entered in the normal command duty value Dtyv ( If the duty value is held) and fvnt2 = 0 (that is, the opening ratio tends to decrease), the process proceeds to step 12, and the latest calculated value Dty Let h be Dtyv.

  In step 13, an operation confirmation control process is performed. This process will be described with reference to the flowchart of FIG. In FIG. 46, in step 1, the normal command duty value Dtyv, the engine speed Ne, the target fuel injection amount Qsol, and the water temperature Tw are read.

The condition determination for entering the operation confirmation control is performed by checking the contents of steps 2, 3, 4, and 5 one by one. When all the items are satisfied, the time until the control execution is further measured. enter. That is,
Step 2: Qsol is less than a predetermined value QSOLDIZ # (that is, at the time of fuel cut),
Step 3: Ne is less than a predetermined value NEDIZ # (that is, a middle rotation speed range).
Step 4: Tw is less than a predetermined value TWDIZ # (that is, before completion of warm-up).
Step 5: Operation confirmation controlled flag fdiz = 0 (operation confirmation control has not been performed yet)
In step 6, the operation confirmation control counter Ctrdiz is incremented.

  The condition for entering the operation confirmation control is not limited to this, and the region where the operation of the actuator 54 is unstable is a region where the engine starts or where the engine exhaust flow rate is low (for example, during deceleration, low load or Low rotation speed).

  In steps 7 and 8, the operation check control counter is compared with predetermined values CTRDIZH # and CTRDIZL #. Here, the predetermined values CTRDIZL # and CTRDIZH # respectively define a lower limit and an upper limit of the operation check control counter. CTRDIZL # is a value of about 2 seconds, for example, and CTRDIZH # is a value of about 7 seconds, for example. Therefore, from the timing when the operation confirmation control counter coincides with CTRDIZL # which is the lower limit, while the operation confirmation control counter is less than CTRDIZH # which is the upper limit, the process proceeds to step 9 to set the operation confirmation control command duty value. That is, CTRDIZH # -CTRDIZL # is the operation confirmation control execution time.

The setting of the operation confirmation control command duty value will be described with reference to the flowchart of FIG. In FIG. 47, the operation check control counter Ctrdiz and the engine speed Ne are read in step 1, and the control pattern Duty is retrieved in step 2 by searching, for example, a table having the contents shown in FIG. 48 from Ctrdiz-CTRDIZL # (≧ 0). Set pu. This moves the variable nozzle 53 between the fully closed position and the fully open position in a short cycle.

  In step 3, the duty value Duty is obtained by searching a table having, for example, FIG. 49 from the engine speed Ne. p set ne and this Duty p In step 4, the above control pattern Duty A value obtained by multiplying pu is calculated as a control command duty value Dtyvnt. As shown in FIG. 49, the control pattern Duty Duty value Duty multiplied by pu p ne is a value corresponding to the engine speed Ne. This assumes that the duty command value for checking the opening / closing operation of the variable nozzle 53 differs depending on the engine speed. For example, the variable nozzle 53 needs to be closed against the exhaust pressure, but the exhaust pressure becomes higher as the rotational speed becomes higher. Therefore, the duty command value is increased accordingly. Further, the value is lowered on the high rotational speed side so as not to be adversely affected by this control.

  Returning to FIG. 46, when the operation confirmation control counter is less than CTRDIZL # as the lower limit, the process proceeds from step 8 to step 15 to set the normal command duty value Dtyv as the control command duty value Dtyvnt.

When the operation confirmation control counter becomes equal to or higher than CTRDIZH # as the upper limit, the process proceeds from step 7 to step 10 to compare Ctrdiz _n-1 as the previous operation confirmation control counter with CTRDIZH # as the upper limit. If Ctrdiz _n-1 <CTRDIZH #, it is determined that the operation confirmation control counter has reached CTRDIZH # or more as the upper limit, and the operation confirmation control is terminated. Therefore, in step 11, the control command duty value Dtyvnt = 0 To do. This is because the variable nozzle 53 is fully opened once at the end of the operation confirmation control to ensure control accuracy during normal control. In step 12, the operation confirmation control completed flag fdiz = 1 is set, and the current process is terminated. Since the flag fdiz = 1 does not allow the process to proceed to step 6 and subsequent times after the next time, the operation confirmation control is not performed twice after the engine is started.

  When the operation confirmation control counter is not immediately after the upper limit CTRDIZH # or more, the process proceeds from step 10 to step 14, and the operation confirmation control counter Ctrdiz = 0 is set in preparation for the next time, and then the process of step 15 is executed. .

  On the other hand, when Qsol is equal to or greater than the predetermined value QSOLDIZ # (not during fuel cut), when Ne is equal to or greater than the predetermined value NEDIZ # (high rotational speed range), Tw is equal to or greater than the predetermined value TWDIZ # (after completion of warm-up). In some cases, in order to prohibit the operation confirmation control, the process proceeds from Steps 2, 3, and 4 to Step 13, and after setting the flag fdiz = 0, the processes in Steps 14 and 15 are executed.

  Above, description of FIG. 15, FIG. 16 is complete | finished.

  Next, FIG. 50 is for calculating two feedback correction coefficients Kqac00 and Kqac0 and an EGR flow rate learning correction coefficient Kqac used for calculating the EGR amount and calculating the EGR flow velocity, and is executed for each input of the REF signal.

  First, in step 1, the target intake air amount tQac, the actual intake air amount Qac, the engine speed Ne, and the target fuel injection amount Qsol are read. In step 2, from the target intake air amount tQac

(Equation 20)
tQacd = tQac × KIN × KVOL × KQA #
+ TQacd _n-1 × (1-KIN × KVOL × KQA #),
Where KIN: volume efficiency equivalent value,
KVOL: VE / NC / VM,
VE: displacement,
NC: number of cylinders
VM: Intake system volume,
KQA #: constant,
tQacd _n-1 : Previous Qacd,
The target intake air amount delay processing value tQacd is calculated by the following equation (primary delay equation). In this case, delay processing is performed so that two feedback correction coefficients Kqac00, Kqac0 and a learning value Rqac, which will be described later, do not increase due to a delay in air supply due to the presence of the intake system volume.

  In step 3, various feedback-related flags are read. These settings will be described with reference to the flowcharts of FIGS. 51, 52, and 53.

  51, 52, and 53 are executed at regular intervals (for example, every 10 ms) independently of FIG.

  FIG. 51 is for setting the feedback permission flag fefb. In step 1, the engine rotational speed Ne, the target fuel injection amount Qsol, the actual EGR rate Megrd, and the water temperature Tw are read.

The feedback permission condition is determined by checking the contents of Steps 2 to 5 and 8 one by one. When all items are satisfied, the feedback is permitted. . That is,
Step 2: Megrd exceeds a predetermined value MEGRFB # (that is, EGR operating range),
Step 3: Tw exceeds a predetermined value TWFBL # (for example, about 30 ° C.),
Step 4: Qsol exceeds a predetermined value QSOLFBL # (no fuel cut),
Step 5: Ne exceeds a predetermined value NEFBL # (not in the rotational speed range where the engine is stalled),
Step 8: When the feedback start counter Ctrfb exceeds a predetermined value TMRFB # (for example, a value less than 1 second), the feedback permission flag fefb = 1 is set to permit feedback in Step 9; otherwise, the process proceeds to Step 10 In order to prohibit the feedback, the feedback permission flag fefb = 0 is set.

  The feedback start counter is incremented when Steps 2 to 5 are established (Step 6), and is reset when Steps 2 to 5 are not established (Step 7).

  FIG. 52 is for setting the learning value reflection permission flag FERN2. In step 1, the engine rotational speed Ne, the target fuel injection amount Qsol, the actual EGR rate Megrd, and the water temperature Tw are read.

The learning value reflection permission condition is also determined by checking the contents of steps 2 to 5 and 8 one by one. When all the items are satisfied, the reflection of the learning value is permitted. Prohibits the reflection of learning values. That is,
Step 2: Megrd exceeds a predetermined value MEGRLN2 # (that is, EGR operating range),
Step 3: Tw exceeds a predetermined value TWLNL2 # (for example, about 20 ° C.),
Step 4: Qsol exceeds the predetermined value QSOLLLNL2 # (no fuel cut),
Step 5: Ne exceeds a predetermined value NELNL2 # (not in the rotational speed range where the engine is stalled),
Step 8: When the learning value reflection counter Ctrlln2 exceeds a predetermined value TMRLN2 # (for example, about 0.5 second), the learning value reflection permission flag fel2 = 1 is set to permit reflection of the learning value in Step 9, and so If not, the process proceeds to step 10 where the learning value reflection permission flag fel2 = 0 is set to prohibit reflection of the learning value.

  The learning value reflection counter is incremented when Steps 2 to 5 are established (Step 6) and reset when Steps 2 to 5 are not established (Step 7).

  FIG. 53 is for setting the learning permission flag FERN. In step 1, the engine rotational speed Ne, the target fuel injection amount Qsol, the actual EGR rate Megrd, and the water temperature Tw are read.

The learning permission condition is determined by checking the contents of steps 2 to 7 and 10 one by one, and learning is permitted when all of the items are satisfied, and learning is prohibited when one of the items is contrary. . That is,
Step 2: Megrd exceeds a predetermined value MEGRLN # (that is, EGR operating range),
Step 3: Tw exceeds a predetermined value TWLNL # (for example, about 70 to 80 ° C.),
Step 4: Qsol exceeds a predetermined value QSOLNLNL # (no fuel cut),
Step 5: Ne exceeds a predetermined value NELNL # (not in the rotational speed range where the engine is stalled),
Step 6: The feedback permission flag fefb = 1.
Step 7: The learning value reflection permission flag FERN2 = 1.
Step 10: When the learning delay counter Ctrlln exceeds a predetermined value TMRLN # (for example, about 4 seconds), the learning permission flag feln = 1 is set in order to permit learning in Step 11, and otherwise, the process proceeds to Step 12. In order to prohibit learning, a learning permission flag feln = 0 is set.

  The learning delay counter is incremented when Steps 2 to 7 are established (Step 8) and reset when Steps 2 to 7 are not established (Step 9).

  Returning to FIG. 50, among the three flags set in this way, the feedback permission flag fefb is seen at step 4. When fefb = 1, the feedback correction coefficient Kqac00 for the EGR amount and the feedback correction coefficient Kqac0 for the EGR flow velocity are calculated in steps 5 and 6. On the other hand, when fefb = 0 (when feedback is prohibited), the process proceeds from step 4 to steps 7 and 8, where Kqac00 = 1 and Kqac0 = 1.

  Here, the calculation of the EGR amount feedback correction coefficient Kqac00 will be described with reference to the flow of FIG. 54, and the calculation of the EGR flow velocity feedback correction coefficient Kqac0 will be described with reference to the flow of FIG.

  First, in FIG. 54 (subroutine of step 5 in FIG. 50), in step 1, the target intake air amount delay processing value tQacd, the actual intake air amount Qac, the engine rotational speed Ne, the target fuel injection amount Qsol, and the water temperature Tw are read.

  In step 2, for example, a map containing the content of FIG. 55 is searched from Ne and Qsol, and the correction gain Gkfb of the EGR flow rate is retrieved in step 3. In step 3, the water temperature correction coefficient Kgfbtw of the correction gain is derived from Tw, for example Each of them is calculated by searching the table, etc.

(Equation 21)
Kqac00 = (tQacd / Qac-1) × Gkfb × Kgfbtw + 1
The EGR amount feedback correction coefficient Kqac00 is calculated by the following equation.

  The first term (tQacd / Qac-1) on the right side of this equation is the error rate from the target intake air amount delay processing value, and by adding 1 to this, Kqac00 becomes a value centered on 1. Equation 21 calculates the EGR amount feedback correction coefficient Kqac00 in proportion to the error rate from the target intake air amount delay processing value.

  Next, in FIG. 57 (subroutine of step 6 in FIG. 50), in step 1, the target intake air amount delay processing value tQacd, the actual intake air amount Qac, the engine rotational speed Ne, the target fuel injection amount Qsol, and the water temperature Tw are read.

  In step 2, for example, a map containing the content of FIG. 58 is searched from Ne and Qsol, and the correction gain Gkfbi of the EGR flow velocity is retrieved. In step 3, the water temperature correction coefficient Kgfbitw of the correction gain is derived from Tw. Each of them is calculated by searching the table, etc.

(Equation 22)
Rqac0 = (tQacd / Qac-1) × Gkfbi × kGfbitw
+ Rqac0 _n-1 ,
Where Rqac0 _n-1 : previous Rqac0,
The error rate Rqac0 is updated by the following equation, and a value obtained by adding 1 in step 5 to the error rate Rqac0 is calculated as an EGR flow velocity feedback correction coefficient Kqac0.

  This calculates the EGR flow velocity feedback correction coefficient Kqac0 in proportion to the integrated value (integrated value) of the error rate (tQacd / Qac-1) from the target intake air amount delay processing value (integral control).

  As shown in FIGS. 55 and 58, the correction gain is set to a value corresponding to the operation condition (Ne, Qsol) for the following reason. This is because hunting occurs or does not occur depending on operating conditions even with the same gain, so that the correction gain is reduced in a region where hunting occurs. The reason why the value is decreased when the water temperature is low (before completion of warm-up) as shown in FIGS. 56 and 59 is to stabilize the engine in a low water temperature region where the engine rotation speed is unstable.

  When the calculation of the EGR amount feedback correction coefficient Kqac00 and the EGR flow velocity feedback correction coefficient Kqac0 is completed in this manner, the process returns to FIG. When the learning reflection permission flag ferln2 = 1 (when the learning value is permitted to be reflected), the process proceeds to step 10, and the error ratio learning value Rqac is read by searching the learning map of FIG. 60 from Ne and Qsol, for example. A value obtained by adding 1 to is calculated as an EGR flow rate learning correction coefficient Kqac. On the other hand, when the learning reflection permission flag felrn2 = 0 (when the reflection of the learning value is prohibited), the process proceeds from step 9 to step 12, and the EGR flow rate learning correction coefficient Kqac = 1 is set.

  Subsequently, at step 13, the learning permission flag FERN is observed. If the learning permission flag ferln = 1 (when learning is permitted), the process proceeds to step 14 where 1 is subtracted from the EGR flow velocity feedback correction coefficient Kqac0 to obtain an error ratio Rqacn. On the other hand, when the learning permission flag FERN = 0 (when learning is prohibited), the process proceeds from step 13 to step 15 to set the error ratio Rqacn = 0.

  Based on the error rate Rqacn thus determined, in step 16, the error rate learned value Rqac is updated. The update of the learning value will be described with reference to the flow in FIG.

  In FIG. 61 (subroutine of step 16 in FIG. 50), in step 1, the error rate Rqacn, the engine speed Ne, and the target fuel injection amount Qsol are read. In step 2, the learning speed Tclrn is calculated from Ne and Qsol by, for example, searching a map having the contents shown in FIG. In step 3, the error ratio learning value Rqac is read from the learning map of FIG. 60 from Ne and Qsol. In step 4

(Equation 23)
Rqac _n = Rqacn × Tclrn + Rqac _n−1 × (1-Tclrn),
Where Rqac _{n is the} updated error rate learned value,
Rqac _n-1 : Error ratio learned value before update (= learned value read value),
The weighted average process is performed according to the following equation, and the updated learning value is stored in the learning map of FIG. 60 in step 5 (the updated value is overwritten on the previous value).

  FIG. 63 (subroutine of step 2 in FIG. 5) is for calculating the EGR flow velocity Cqe.

  In steps 1 and 2, the actual EGR amount Qec, the actual EGR rate Megrd, the actual intake air amount Qac, the EGR flow velocity feedback correction coefficient Kqac0, and the EGR flow velocity learning correction coefficient Kqac are read.

(Equation 24)
Qec h = Qec × Kqac × Kqac0
The value obtained by correcting the actual EGR amount Qec with Kqac0 and Kqac is calculated as the corrected actual EGR amount Qec. Calculated as h, and this corrected actual EGR amount Qec In step 8, the EGR flow rate Cqe is calculated by searching a map having the contents of FIG. 64, for example, from h and the actual EGR rate Megard. Steps 4 to 7 that have not been described will be described later.

  The characteristics of the EGR flow velocity in FIG. 64 indicate that the non-linearity is strong and the sensitivity of EGR feedback differs depending on the operation conditions, so that the EGR flow velocity feedback is small so that the difference in the feedback amount with respect to the operation conditions is small. The correction coefficient Kqac0 is used as feedback to the actual EGR amount Qec used for searching the flow velocity map.

  However, in FIG. 64, the portion close to the right end where the slope of the characteristic is steep is an area in which a matching error of the map tends to occur. Therefore, if there is a matching error, the EGR valve opening area Aev is affected by the matching error. Will change. That is, in Aev = Tqek / Cqe, which is an expression for calculating the EGR valve opening area Aev, an adaptation error occurs in Cqe. In order to cope with this, correction of the flow rate error is also made for the target EGR amount Tqek. Need to do. For this reason, the EGR amount feedback correction coefficient Kqac00 is newly introduced, and the target EGR amount Tqek is corrected in step 6 of FIG. 7 by this Kqac00.

  In this case, the above equation (20), which is an equation for calculating Kqac00, calculates Kqac00 in proportion to the error rate from the target intake air amount delay processing value. Therefore, the proportional error of the EGR flow velocity map of FIG. Can be corrected immediately. For example, for simplicity, in Equation 20, when considering the correction gain Gkfb = 1 and the completion of warm-up, Kqac00 = (tQacd / Qac−1) +1. In this case, if the actual intake air amount Qac is smaller than tQacd as the target value, Kqac00 becomes a value larger than 1, and thus Tqec is immediately reduced. When the target EGR amount is immediately reduced, the new air amount (intake air amount) relatively increases, and thereby the actual intake air amount Qac converges to tQacd as the target value.

Steps 4 to 7 in FIG. 63 which are not described are for setting initial values at the start of the EGR operation. Specifically, in step 4, the corrected actual EGR amount Qec Compare h with 0. Qec When h = 0 (that is, when the EGR is not operated), the process proceeds to Step 5;

(Equation 25)
Qec h = Qac × MEGRL #,
Where MEGRL #: constant,
The corrected actual EGR amount Qec Set h. Similarly, in step 6, the actual EGR rate Megrd is compared with 0, and when Megrd = 0,

(Equation 26)
Megrd = MEGRL #
The actual EGR rate Megard is set by the following formula.

The EGR flow velocity that passes through the EGR valve 6 when the EGR valve 6 is fully closed is naturally zero, but Equations 25 and 26 are parameters used for calculating the flow velocity in consideration of the start of EGR operation. Set the initial value of. The value of MEGRL # is, for example, 0.5 as described above. More specifically, the differential pressure before and after the EGR valve at the start of EGR operation (and therefore the EGR flow rate) varies depending on the operating conditions, and this is addressed. In this case, the differential pressure before and after the EGR valve at the start of EGR operation is related to the actual intake air amount Qac. Therefore, Qec is proportional to Qac according to Equation 25. By giving the initial value of h, the calculation accuracy of the EGR flow velocity at the start of the EGR operation is improved.

  Here, the operation of the two embodiments will be described.

  According to the present embodiment, when the variable nozzle 53 is driven by the actuator 54 that receives the supply of pressure according to the command value, the target opening ratio (operation target value of the supercharger) is increased or decreased. The command value given to the pressure control valve 56 is made different between the increasing direction and the decreasing direction from the determination result, even if the target opening ratio is the same. In order to obtain the same target opening ratio when the actuator 54 is moved in the direction in which the target opening ratio decreases due to the exhaust reaction force, etc., and when the actuator 54 is moved in the direction in which the target opening ratio increases in reverse. Even if there is hysteresis in the actuator 54 that the command value differs, the target opening ratio is obtained regardless of which direction the opening ratio changes. It is possible.

In the case of the actuator 54 in which the opening ratio and the command value have hysteresis characteristics and nonlinear characteristics, the target opening ratio Rvnt (or the command opening ratio Avnt) is set to the command duty value Dty. In order to convert to h (command value), a control map for storing a command duty value corresponding to the target opening ratio Rvnt needs to be stored for each change direction of the target opening ratio, and should be stored. The amount of data increases. On the other hand, in the present embodiment, the target opening ratio Rvnt is converted into a linearization processing value Ratdty having a linear relationship with the command duty value using a predetermined linearization function (see FIG. 32), and this linearization processing value Ratdty. Is converted into the command duty value, the command value Duty when the linearization processing value Ratdty is 0 is determined according to the determination result for determining whether the change direction of the target opening ratio is the increasing direction or the decreasing direction. Command value Duty when l and linearization processing value Ratdty are 1 Two command values Dhty read out from the means for storing h for each change direction of the target opening ratio Rvnt l and Duty The command value Duty when the difference of h is the slope and the linearization processing value Ratdty is 0 A linear function having l as an initial value is generated, and the linearization processing value Ratdty is converted into a command duty value Dty using the generated linear function. Since it is converted to h (command value to the actuator), a linearization function (control map) for converting the target opening ratio Rvnt to a linearization processing value Ratdty and four data for generating two linear functions (Duty l p, Duty l n, Duty h p, Duty h n) need only be stored, and this reduces the amount of data to be stored.

When feedforward control or feedback control is added to the control of the variable nozzle 53 (exhaust flow adjusting means), the target opening ratio Rvnt (operation basic target value) is converted into a command value, and then the command value is converted into a feedforward amount or a feedback amount. In this method, the hysteresis characteristic of the actuator is not reflected in the feedforward amount and the feedback amount, and it is difficult to perform stable control. It is also possible to consider the hysteresis characteristics of the actuator when calculating the feedforward amount and the feedback amount. In this case, the feedforward means and the feedback means need to be provided with hysteresis processing means, respectively. It becomes complicated and is not preferable. On the other hand, in this embodiment, when calculating the command opening ratio Avnt (operation target value), the feedforward amount Avnt f and feedback amount Avnt fb is reflected, and this command opening ratio Avnt is set to the command duty value Dty. Since hysteresis processing is performed when converting to h (command value), an efficient control system can be obtained.

In addition, when the relationship between the operation amount of the actuator 54 (= the operation state of the variable nozzle 53) and the command value varies depending on the temperature of the actuator 54, in this embodiment, the command duty value Dty is based on the temperature of the actuator 54. Since h (command value to the actuator) is corrected, the variable nozzle 53 can always be adjusted to a desired state regardless of the temperature of the actuator 54.

Also, the command duty value Dty When correcting h, the exhaust temperature Texhb after completion of engine warm-up (actuator temperature after completion of engine warm-up) is calculated based on the engine speed and engine load, and a predetermined delay process is performed for this exhaust temperature Texhb. The current exhaust temperature Texhdly (current actuator temperature) is calculated and based on the difference between these two temperatures Texhb and Texhdly, so the target opening ratio Rvnt (operation target value) is set as the command duty value (command value). When the function to convert to is adapted in the state after the engine warm-up is completed, the command duty value is corrected by the difference between the actuator temperature after the engine warm-up is completed and the current actuator temperature. Regardless of the temperature of the actuator 54, the variable nozzle 53 is always adjusted to a desired state. Can.

  When the supercharging pressure (air amount) is controlled by the variable nozzle 53, as described above with reference to FIG. 33, the change in the supercharging pressure with respect to the change in the opening area between the large opening area and the small opening area. Since the width is greatly different, if the feedback amount of the opening area is obtained using a constant feedback gain, the response and stability of the control differ between the region having a large opening area and the region having a small opening area. In this embodiment, the feedback gain is set based on the engine speed and the engine load, which are the main parameters for determining the opening area of the variable nozzle 53, so that the same control response and stability are always obtained. Obtainable.

  Further, when setting the feedback gain, the feedback gain correction coefficient Kh is calculated based on the engine speed and the engine load, and the basic values (KPB #, KIB #, KDB #) of the feedback gain are corrected by the correction coefficient Kh. Since the obtained value is set as the feedback gain, the adaptation becomes easier than setting the feedback gain itself corresponding to the engine speed and the engine load.

  On the other hand, according to the present embodiment, control for confirming the operation of the actuator 54 regardless of the target opening area Rvnt (operation target value), for example, by operating from the lower limit to the upper limit of the operation range of the actuator 54, Since the operation is smooth over the entire operating range and the response of the actuator 54 is improved, it is possible to prevent the movement of the actuator 54 from becoming sluggish due to astringency or the like and being unable to drive to the target opening ratio Rvnt, thereby inhaling Control accuracy of air quantity and supercharging pressure is improved.

The command value for moving the lower limit to the upper limit of the operating range of the actuator 54 differs depending on the engine rotation speed. According to the present embodiment, the control pattern Duty for repeatedly operating the actuator 54 from the lower limit to the upper limit of the operating range in a short cycle. Du (Duty value) according to pu (third command value) and engine speed p Since the product of ne (fourth command value) is generated as the control command duty value Dtyvnt (second command value), the command value for moving from the lower limit to the upper limit of the operating range of the actuator differs depending on the engine speed In addition, it is possible to cope with this by setting in advance a command value corresponding to the engine speed.

  Although the control of the operation of the actuator 54 is performed in all the operating ranges, it may affect the amount of intake air, even though it is a countermeasure against the astringency of the actuator 54. However, according to the present embodiment, the operation of the actuator 54 is confirmed. Since the operation area to be controlled is limited to the operation area when the engine is started, before the warm-up of the engine is completed or the engine exhaust flow rate is small, the intake air amount is not affected.

In the embodiment, the feedforward amount Avnt for compensating for the dynamics of the actuator 54 based on the target opening ratio Rvnt (the basic operation target value of the exhaust flow adjusting means). f is calculated, and the feedback amount Avnt is calculated based on the ratio between the target intake air amount tQac (supercharging pressure parameter target value) and the actual intake air amount Qac (supercharging pressure parameter actual value). calculate fb and these two values Avnt f, Avnt Although the case where the sum of fb is set as the command opening ratio Avnt (operation target value) has been described, the feedforward amount Avnt f, feedback amount Avnt Only one of fb may be calculated. Also, feedback amount Avnt fb can also be calculated based on the difference between the target intake air amount tQac and the actual intake air amount Qac.

In the embodiment, the command duty value Dty is based on the difference between the two exhaust temperatures Texhb and Texhdly. As described in the case of correcting h, the command duty value Dty is based on the ratio of the two exhaust temperatures Texhb and Texhdly. It is also possible to correct h.

In the embodiment, the command value Duty when the variable nozzle is fully closed h and the command value Duty when the variable nozzle is fully open 1 for the engine speed and engine load, and the difference between these two command values (Duty h-Duty l) multiplied by the target opening ratio Rvnt and a command value Duty when the variable nozzle is fully opened. Although the case where the value obtained by adding 1 is calculated as the command duty value basic value Dtyv has been described, it goes without saying that the target opening area may be used instead of the target opening ratio Rvnt.

In the embodiment, the exhaust gas temperature is predicted, and the command duty value basic value Dty is determined by a difference between the predicted exhaust gas temperature Texhi and a value Texhdly obtained by performing a delay process for thermal inertia on the predicted exhaust gas temperature. As described in the case of correcting h (see step 9 in FIG. 34), the exhaust temperature is predicted, and the command duty value basic value Dty is determined by the predicted exhaust temperature Texhi. You may correct | amend h.

  In the embodiment, a target intake air amount tQac is calculated, and a target opening ratio Rvnt that is an operation target value of the supercharger is calculated based on this value and the actual EGR amount Qec that is the actual control value of the EGR device and the actual EGR rate Megrd. Although described in the case of setting, the target supercharging pressure may be used instead of the target intake air amount tQac.

  In the embodiment, the turbocharger in which the supercharging pressure changes according to the opening ratio of the variable nozzle has been described. However, the present invention is not limited to this, and the following is also applicable.

<1> Another type of turbocharger in which the supercharging pressure changes according to the flow rate,
<2> A turbocharger of a certain capacity equipped with a wastegate valve,
<3> Supercharger,
For example, for the turbocharging pressure of <1>, the opening ratio and opening area of the flow rate variable means of the turbocharger or the control ratio and operating ratio given to the actuator for driving the turbocharger are set to <2>. For turbochargers, the opening ratio and opening area of the wastegate valve, and for the supercharger of <3>, the control ratio and operating ratio given to the actuator for driving the supercharger are the operation targets of the supercharger. It can be used as a value.

  In the embodiment, it has been described that the actuator of the turbocharger is operated using pressure, and the variable nozzle of the turbocharger is driven by the actuator that receives the supply of pressure. However, the above <1>, <2> This also applies to other turbochargers.

  In the embodiment, the case where so-called low-temperature premixed combustion is performed in which the heat generation pattern is single-stage combustion has been described. However, even in the case of normal diesel combustion in which diffusion combustion is added after premixed combustion, It goes without saying that the invention can be applied.

The control system figure of one Embodiment. The schematic block diagram of a common rail type fuel injection device. The flowchart for demonstrating the calculation of target fuel injection amount. The map characteristic figure of basic fuel injection amount. The flowchart for demonstrating the calculation of an EGR valve opening area. The characteristic view of the EGR valve drive signal with respect to the EGR valve opening area. The flowchart for demonstrating calculation of the target EGR amount. The flowchart for demonstrating the calculation of cylinder intake air amount. The flowchart for demonstrating the detection of the amount of intake air. The characteristic figure of the amount of intake air with respect to an air flow meter output voltage. The flowchart for demonstrating the calculation of a target EGR rate. The map characteristic figure of a basic target EGR rate. The table characteristic figure of a water temperature correction coefficient. The flowchart for demonstrating complete explosion determination. The flowchart for demonstrating the calculation of the control command duty value given to the pressure control valve of 1st Embodiment. The flowchart for demonstrating the calculation of the control command duty value given to the pressure control valve of 2nd Embodiment. The flowchart for demonstrating the calculation of a real EGR rate. The flowchart for demonstrating the calculation of the time constant equivalent value for collector capacity. The map characteristic figure of volume efficiency equivalent basic value. The flowchart for demonstrating the calculation of target intake air amount. The map characteristic figure of the target intake air amount basic value at the time of EGR operation. The map characteristic figure of a target intake air amount correction coefficient. The map characteristic figure of the target intake air amount at the time of EGR non-operation. The flowchart for demonstrating the calculation of the amount of real EGR. The flowchart for demonstrating the calculation of the target opening ratio of 1st Embodiment. The map characteristic figure of a target opening ratio. The flowchart for demonstrating the calculation of the target opening ratio of 2nd Embodiment. The map characteristic figure of a target opening ratio. The flowchart for demonstrating the calculation of the feedforward amount of a target opening ratio. The flowchart for demonstrating the calculation of the feedback amount of a target opening ratio. The flowchart for demonstrating a linearization process. The table characteristic figure of linearization. The characteristic view which shows the relationship between opening area and supercharging pressure. The flowchart for demonstrating signal conversion. The flowchart for demonstrating the setting of a duty selection signal flag. The flowchart for demonstrating the calculation of the temperature correction amount of a duty value. The map characteristic figure of basic exhaust temperature. The table characteristic figure of a water temperature correction coefficient. The table characteristic figure of temperature correction amount. The temperature characteristic figure of the actuator for a turbocharger drive. The map characteristic figure of the duty value at the time of a variable nozzle fully closed. The map characteristic figure of the duty value at the time of a variable nozzle full open. The map characteristic figure of the duty value at the time of a variable nozzle fully closed. The map characteristic figure of the duty value at the time of a variable nozzle full open. The hysteresis diagram when converting a command opening ratio linearization process value into a duty value. The flowchart for demonstrating operation | movement confirmation control. The flowchart for demonstrating the setting of operation check control command duty value. The table characteristic figure of a control pattern. The table characteristic figure of the duty value at the time of operation check control. The flowchart for demonstrating the calculation of two feedback correction coefficients and learning correction coefficients of EGR control. The flowchart for demonstrating the setting of a feedback permission flag. The flowchart for demonstrating the setting of a learning value reflection permission flag. The flowchart for demonstrating the setting of a learning permission flag. The flowchart for demonstrating the calculation of an EGR amount feedback correction coefficient. The map characteristic figure of the correction | amendment gain of an EGR flow volume. The table characteristic figure of a water temperature correction coefficient. The flowchart for demonstrating the calculation of an EGR flow velocity feedback correction coefficient. The map characteristic figure of the correction | amendment gain of an EGR flow velocity. The table characteristic figure of a water temperature correction coefficient. The table of the learning map of an error ratio learning value. The flowchart for demonstrating the update of a learning value. The map characteristic figure of learning speed. The flowchart for demonstrating the calculation of an EGR flow velocity. The map characteristic figure of EGR flow velocity.

Explanation of symbols

41 Control Unit 52 Exhaust Turbine 53 Variable Nozzle 54 Actuator 55 Diaphragm Actuator 56 Pressure Control Valve

Claims (1)

A turbocharger that supercharges the air that the engine takes in through the intake passage;
Exhaust flow adjusting means for adjusting the flow rate or flow rate of the exhaust gas flowing into the exhaust turbine of the turbocharger;
An actuator that receives supply of pressure according to a command value and drives the exhaust flow adjusting means;
An operation target value setting means for setting an operation target value of the exhaust flow adjusting means;
Conversion means for converting the operation target value into the command value using a predetermined function;
Rutotomoni a command value correcting means for correcting a command value of the actuator f based on a temperature of the actuator,
A detecting means for detecting the engine speed and the engine load;
The command value correcting means includes a first temperature calculating means for calculating a temperature of the actuator after completion of engine warming based on a detection result of the detecting means, and a predetermined value for the temperature calculated by the first temperature calculating means. Second temperature calculating means for performing a delay process to calculate the current temperature of the actuator, and a difference or ratio between the temperature calculated by the first temperature calculating means and the temperature calculated by the second temperature calculating means. A turbocharger control device that corrects a command value to the actuator based on the control value.

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