JP2519190B2 - Control method for boost pressure of internal combustion engine - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling supercharging pressure of an internal combustion engine, and more particularly to a control method for appropriately controlling supercharging pressure in a transient state.

(Prior Art) As a conventional method for controlling the supercharging pressure of an internal combustion engine for a vehicle, open loop control is performed when the supercharging pressure is in a transient state such as a rapid rise, and feedback control is performed when it is in a steady state. What has been done has already been proposed by the applicant (Japanese Patent Laid-Open No. 63-12).
No. 9126), which prevents the control hunting due to the response delay of the control system when the feedback control is performed in the transient state to perform the smooth supercharging pressure control.

Further, in such a supercharging pressure control method, in order to compensate for the deviation of the supercharging pressure control due to variations due to mass production of the control system or deterioration over time, the control amount of the supercharging pressure during open loop control Is set based on the learning value calculated at the time of feedback control, and paying particular attention to the fact that the intake air temperature has a large influence on the supercharging pressure, and the learning value is calculated separately for each region according to the intake air temperature. What has made it possible to perform more appropriate supercharging pressure control has already been proposed by the present applicant (for example, JP-A-63-129127).

(Problems to be Solved by the Invention) However, the above-described conventional control method has room for improvement in appropriately controlling the supercharging pressure in a transient state.

That is, the feedback control region in which the learning value is calculated is the steady state of the supercharging pressure. However, even if the region corresponding to the intake air temperature is the same in this steady state, the state of the supercharging pressure is not always constant. Not like. For example, when the target supercharging pressure of the feedback control is set to a value different from the normal value, the supercharging pressure state also changes with the change of the target supercharging pressure. On the other hand, in the conventional control method described above, if the boost pressure is in a steady state, the learning value is calculated for each region according to the intake air temperature regardless of the change in the boost pressure state as described above. As a result, the learning value calculated at this time also fluctuates in the same region as the supercharging pressure state changes. As a result, it is not possible to set the control amount of the supercharging pressure by applying an appropriate learning value during the open loop control, so that the supercharging pressure at this time is deviated, so that the proper control of the supercharging pressure cannot be performed. I can't do it.

The present invention has been made in order to solve the above-mentioned problems of the conventional technique, and prevents the deviation of the supercharging pressure in a transient state, and thus makes it possible to appropriately control the supercharging pressure. It is an object to provide a pressure control method.

(Means for Solving the Problem) In order to achieve the above-mentioned object, the present invention is a control amount for operating a supercharging pressure control unit, the control amount being corrected by a correction value that depends on at least one engine operating parameter. In a method of controlling a supercharging pressure of an internal combustion engine for controlling the supercharging pressure by controlling, a feedback control step of controlling the control amount according to a deviation between an actual supercharging pressure and a target supercharging pressure, and A learning value calculation step of obtaining a learning value of the correction value by calculating the correction value applied during the feedback control step, and the learning value calculation step of calculating the correction value based on the learning value of the correction value calculated in the learning value calculation step. An open control step for performing open control of the controlled variable, a selection step for selecting the feedback control step and the open control step according to the operating state, and the feedback control step The target supercharging pressure is a target supercharging pressure setting step that sets different target supercharging pressures in normal time and when a predetermined condition is satisfied, and the learning value in the learning value calculation step when the predetermined condition is satisfied. And a learning value calculation prohibiting step of prohibiting the calculation of.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.
Referring first to FIGS. 1 to 4, there is shown an internal combustion engine equipped with a boost pressure control device to which the method of the present invention is applied.

An intake manifold 1 is connected to an intake port of each cylinder in an engine body E of a multi-cylinder internal combustion engine, and the intake manifold 1 further includes an intake pipe 2, a throttle body 3, an intercooler 4, and an air cleaner 6 via a variable capacity turbocharger 5. Connected to. An exhaust manifold 7 is connected to the exhaust port of each cylinder, and the exhaust manifold 7 is connected to a three-way catalytic converter 9 via an exhaust pipe 8 in which a variable capacity turbocharger 5 is provided in an intermediate portion. Further, a fuel injection valve 10 for injecting fuel toward the intake port of each cylinder is attached to a portion of the intake manifold 1 close to each intake port.

The variable capacity turbocharger 5 is provided with a water jacket 11, and an inlet of the water jacket 11 and an inlet of the intercooler 4 are connected in parallel to a discharge port of a water pump 13 having a suction port connected to a radiator 12, The outlets of the water pump 13 and the intercooler 4 are connected to the radiator 12. Moreover, the radiator 12 is provided separately from the radiator for cooling water in the engine body E.

Next, the configuration of the variable-capacity turbocharger 5 will be described with reference to FIGS. 2, 3 and 4.
And a back plate for closing a back surface of the compressor casing 14.
15, a bearing casing 17 that supports the main shaft 16, and a turbine casing 18.

A scroll passage 19 is defined between the compressor casing 14 and the back plate 15, and an inlet passage 20 extending in the axial direction is formed at the center of the compressor casing 14. In addition, a compressor wheel 21 is attached to one end of the main shaft 16 at a portion located at the center of the scroll passage 19 and at the inner end of the entrance passage 20.

Compressor casing 14 and back plate 15 have multiple bolts
It is fastened by 22 and the bearing casing 17 is connected to the central portion of the back plate 15. A pair of bearing holes 23, 24 are coaxially formed in the bearing casing 17 at an interval from each other, and are provided between the main shaft 16 inserted in these bearing holes 23, 24 and the bearing holes 23, 24. Radial bearing metals 25 and 26 are interposed therebetween, whereby the main shaft 16 is rotatably supported by the bearing casing 17. A collar 27, a thrust bearing metal 28, and a bushing 29 are interposed between the step 16a facing the compressor wheel 21 side of the main shaft 16 and the compressor wheel 21 in this order from the step 16a side. By screwing a nut 30 in contact with the outer end of the main shaft 16 to one end of the main shaft 16 to fasten the main shaft 16 in the thrust direction and mounting the compressor wheel 21 to the main shaft 16.

A lubricating oil introduction hole 32 connected to a lubricating oil pump (not shown) is provided in the upper part of the bearing casing 17, and inside the bearing casing 17, radial lubricating metal 25, 26 and thrust bearing metal 28 A lubricating oil passage 33 for guiding the supplied lubricating oil is provided. Further, at the bottom of the bearing casing 17, there is provided a lubricating oil discharge port 34 for discharging the lubricating oil flowing out from each lubricating portion downward, and the lubricating oil discharged from this lubricating oil discharge port 34 is an oil (not shown). Collected in sump.

The bushing 29 has a through hole 35 formed in the central portion of the back plate 15.
A seal ring 36 is interposed between the outer surface of the bushing 29 and the inner surface of the through hole 35 to prevent the lubricating oil flowing out of the thrust bearing metal 28 from flowing to the compressor wheel 21 side. Is done. A guide plate 37 is inserted between the back plate 15 and the thrust bearing metal 28 to allow the brushing 29 to pass therethrough. Therefore, the lubricating oil that has flowed out from the thrust bearing metal 28 is scattered radially outward from the pushing 29 and is received by the guide plate 37. In addition, the lower portion of the guide plate 37 is formed to be curved so as to guide the received lubricating oil to the lubricating oil discharge port 34 smoothly.

The bearing casing 17 has a water jacket around the main shaft 16.
11 and a water pump is provided on the water jacket 11.
A water supply port 38 for guiding water from 13 (see FIG. 1) and a water outlet 39 for guiding water from water jacket 11 to radiator 12 (see FIG. 1) are provided. In addition, the water jacket 11 is formed in an annular shape surrounding the main shaft 16 in a portion near the turbine casing 18 and has a lubricating oil discharge port 34.
The water supply port 38 is formed in the bearing casing 17 so as to communicate with the lower part of the water jacket 11 at a portion corresponding to the upper part of the water jacket 11 so as to have a substantially U-shaped cross-sectional shape opened downward above the main shaft 16. The water outlet 39 is provided in the bearing casing 17 so as to communicate with the upper part of the water jacket 11.

In the turbine casing 18, a scroll passage 41,
An inlet passage 42 communicating with the scroll passage 41 and extending in the tangential direction, and an outlet passage 43 communicating with the scroll passage 41 and extending in the axial direction are provided.

The bearing casing 17 and the turbine casing 18 are coupled to each other so that the back plate 44 is sandwiched between them. That is, a plurality of stud bolts 45 are screwed to the turbine casing 18, and a nut 47 for screwing a ring member 46 engaged with the bearing casing 17 to the stud bolt 45.
As a result, the bearing casing 17 and the turbine casing 18 are connected to each other, and the flange portion 44a provided on the outer peripheral portion of the back plate 44 is sandwiched between the bearing casing 17 and the turbine casing 18.

A fixed vane member 48 is fixed to the back plate 44, and the inside of the scroll passage 41 is fixed to the outer peripheral path 41 by the fixed vane member 48.
a and an inflow passage 41b. The fixed vane member 48 includes
A cylindrical portion 48a coaxially fitted in the outlet passage 43;
A disk portion 48b extending radially outward from the outer surface of the intermediate portion of
A plurality of, for example, four fixed vanes 49 extending from the outer peripheral end of the disk portion 48b toward the back plate 44, and a turbine wheel 50 provided at the other end of the main shaft 16 is provided with the fixed vane member 48.
It is stored inside. The cylindrical portion 48a is fitted into the outlet passage 43 via a seal ring 51 fitted to the outer surface thereof, and the fixed vane 49 is joined to the back plate 44 by the bolt 52.

The fixed vanes 49 are provided on the outer peripheral portion of the turbine member 48 at positions equidistantly arranged in the circumferential direction, and each fixed vane 49 is formed in an arc shape. A movable vane having one end fixed to a rotating shaft 53 rotatably pivotally attached to the back plate 44 in parallel with the axis of the main shaft 16 between the fixed vanes 49.
The movable vanes 54 adjust the flow area of the gap between the fixed vanes 49.

Each movable vane 54 is formed in an arc shape having a curvature equivalent to that of the fixed vane 49, and includes a fully closed position indicated by a solid line in FIG.
It is rotatable between a fully open position indicated by a chain line. Moreover, each rotating shaft 53 is connected to the actuator 60 via the link mechanism 55 arranged between the back plate 44 and the bearing casing 17, and the movable vanes 54 are synchronously opened and closed by the operation of the actuator 60. It

A shield plate 56 extending to the back of the turbine wheel 50 is sandwiched between the back plate 44 and the bearing casing 17, and the heat of the exhaust gas flowing through the inflow passage 41b is directly transmitted to the inside of the bearing casing 17 by the shield plate 56. Is prevented as much as possible. In order to prevent the exhaust gas from leaking into the bearing casing 17, a main shaft is installed inside the turbine casing 18.
Through hole provided in bearing casing 17 through which 16 should be projected
At a portion corresponding to 57, the main shaft 16 is provided with a plurality of annular grooves 58 that function as labyrinth grooves.

In such a variable capacity turbocharger 5, the engine body E
Exhaust gas discharged from the inflow passage 41b flows from the inlet passage 42 into the outer peripheral passage 41a at a flow velocity corresponding to the flow area of the gap between the movable vane 54 and the fixed vane 49 corresponding to the rotation amount of the variable vane 54. Then, the turbine wheel 50 is driven to rotate and is discharged from the outlet passage 43. At this time, when the flow area of the gap between each movable vane 54 and the fixed vane 49 decreases, the rotation speed of the turbine wheel 50, that is, the main shaft 16 increases, and the flow area of the gap between each movable vane 54 and the fixed vane 49 increases. Turbine wheel 50 or main shaft
16 rotation speed becomes slow. The compressor wheel 21 rotates in accordance with the rotation of the turbine wheel 50, and the air guided from the air cleaner 6 to the inlet passage 20 is supplied to the intercooler 4 through the scroll passage 19 while being compressed by the compressor wheel 21. become. Accordingly, when the movable vane 54 is located at the outermost position in the radial direction of the turbine casing 18 to minimize the air flow area between the movable vane 54 and the fixed vane 49, the supercharging pressure is maximized. The supercharging pressure becomes minimum when the air flow area between the stationary vane 49 and the stationary vane 49 is maximized by being positioned at the innermost position in the direction.

The temperature rise of the bearing casing 17 due to the temperature rise at the time of air compression in the variable capacity turbocharger 5 is prevented as much as possible by the supply of the cooling water to the water jacket 11, and the rise of the intake air temperature is supplied by the cooling water to the intercooler 4. To be prevented.

Referring again to FIG. 1, an actuator 60 for driving the movable vane 54 of the variable capacity turbocharger 5 includes a housing 61, and a diaphragm 64 that partitions the inside of the housing 61 into a first pressure chamber 62 and a second pressure chamber 63. , 1st pressure chamber
A return spring 65 interposed between the housing 61 and the diaphragm 64 to urge the diaphragm 64 in a direction to contract the 62
And a drive rod 66 whose one end is connected to the diaphragm 64 and which penetrates the housing 61 on the second pressure chamber 62 side in an airtight and movable manner and whose other end is connected to the link mechanism 55. Moreover, the drive rod 66 and the link mechanism 55 cause the movable vanes 54 to move radially inward of the turbine casing 18 when the diaphragm 64 bends in the direction of contracting the second pressure chamber 63 and the drive rod 66 extends. Rotate each fixed vane
It is connected so as to increase the void communication area between the two.

The first pressure chamber 62, together with the intake passage between the variable capacity turbocharger 5 and the intercooler 4 is a regulator 67 to supply the supercharging pressure P _2, it is connected via a throttle 68 and the electromagnetic control valve 69, an air cleaner 6 The intake passage between the variable capacity turbocharger 5 and the variable capacity turbocharger 5 is connected via a throttle 75.
The electromagnetic control valve 69 is a normally closed type valve and is duty-controlled, and the pressure of the first pressure chamber 62 increases as the valve closing duty ratio of the solenoid 70 thereof decreases. Through the link mechanism 55, the movable vanes 54 of the variable capacity turbocharger 5 are driven to rotate inward, that is, to the valve opening side. An intake passage downstream of the throttle body 3 is connected to the second pressure chamber 63 via a check valve 71 and an electromagnetic opening / closing valve 72 so as to supply the intake pressure P _B. The electromagnetic on-off valve 72 is a normally closed type that opens in response to the excitation of its solenoid 73, and the intake pressure P _B is supplied to the second pressure chamber 63 in response to the opening of the electromagnetic on-off valve 72. Then, the actuator 60 moves the movable vanes 54 of the variable capacity turbocharger 5.
Drive inward.

The electromagnetic control valve 69 and the electromagnetic opening / closing valve 72 are controlled by the control means C, and the control means C includes the engine body E.
A temperature detector S _W to detect the water temperature T _W of the provided water jacket (not shown) within the intake air temperature sensor S _A for detecting the intake air temperature T _A of the downstream side of the intercooler 4, an air cleaner 6 and An intake pressure sensor S _PA that detects an intake pressure P _A between the variable displacement turbocharger 5 and a supercharging pressure sensor S _P2 that detects a supercharging pressure P ₂ in an intake passage between the variable displacement turbocharger 5 and the intercooler 4, An intake pressure sensor S _PB that detects an intake pressure P _B on the downstream side of the throttle body 3, a rotation speed detector S _N that detects an engine speed N _E , and a throttle body 3
Throttle opening detector S _TH for detecting the opening θ _TH of the throttle valve 74 and vehicle speed detector S for detecting the vehicle speed V
_V and a shift position detector S _S for detecting the shift position in the automatic transmission are connected. Thus, the control means C
The solenoids 70, 73 based on their input signals.
Control the excitation and demagnetization of.

Next, the control procedure in the control means C will be described. First, the duty ratio control of the solenoid 70 in the electromagnetic control valve 69 will be described with reference to the main routine of FIG. However, the valve closing duty ratio D _OUT for controlling the excitation and demagnetization of the solenoid 70 in this main routine, that is, the ratio of the closing time in one cycle of opening and closing of the valve 69, is increased as the value increases. Becomes smaller, D _OUT = 0% corresponds to the maximum opening, and D _OUT = 10
0% corresponds to the minimum opening.

In step S1, it is determined whether the engine is in the starting mode, that is, whether the engine is cranking. In the start mode, the duty ratio D _OUT is set to 0 in step S2, that is, the electromagnetic control valve 69 is fully opened to set the maximum air flow area between the movable vanes 54 and the fixed vanes 49. This is because the engine is in an unstable state during cranking, and introducing supercharging pressure into the combustion chamber in such an unstable state promotes instability, so the movable vane 54 and the fixed vane 49 This is to prevent the supercharging pressure from being introduced into the combustion chamber by maximizing the void flow area between the two. Also, during cranking, the driver does not request supercharging of the intake air, and it is not necessary to reduce the gap flow area between the movable vanes 54 and the fixed vanes 49. In the next step S3, a timer t for delaying the start of feedback control
_FBDLY is reset, and then the duty ratio D _OUT is output from step S4.

The timer t _FBDLY is intended to be computed in accordance with the procedure shown in FIG. 6, one of the supercharging pressure P by ₂ rate of change [Delta] P ₂ 3 two timers t _FBDLY1, t _FBDLY2, t _FBDLY3 is selected. Here, the change rate ΔP ₂ is the boost pressure P of this time.
_2n and the boost pressure P _2n-6 six times before (ΔP ₂ = P _2n −
P _2n-6 ). That is, the main routine shown in FIG. 5 is executed for each TDC signal pulse, but since the rate of change of the supercharging pressure P ₂ is too small with only one TDC signal, the supercharging pressure behavior, that is, the rate of change ΔP ₂ is accurately determined. In order to read in, the difference from the supercharging pressure P _2n-6 6 times before is obtained.
Further, the set low change rate ΔP _2PTL and the set high change rate ΔP _2PTH are predetermined according to the engine speed N _E ,
T _FBDLY is set when ΔP ₂ ≦ ΔP _2PTL , and ΔP _2PTL <
When ΔP ₂ ≦ ΔP _2PTH , t _FBDLY2 is set, and ΔP _2PTH
When <ΔP ₂ , t _FBDLY3 is set. Moreover, t _FBDLY1
<T _FBDLY2 <t _FBDLY3 , when the supercharging pressure change rate ΔP ₂ is small, that is, when the supercharging pressure P ₂ is changing slowly, the delay time is set to be small, and when the supercharging pressure change rate ΔP ₂ is large. That is, when the supercharging pressure P ₂ is changing rapidly, the delay time is set large. As a result, the time t _FBDLY without excess or deficiency is set at the time of the transition from the open loop control to the feedback control, and it is possible to sufficiently avoid the occurrence of the hunting phenomenon at the time of the transition.

When it is determined not to be the start mode at step S1, it is determined whether the water temperature T _W is less than the set low temperature T _WL is in step S5, the process proceeds to step S2 when setting is less than the low water temperature T _WL. Here, the operating state of the engine considered as the case where T _W <T _WL is satisfied is, for example, when the engine is initially started or when the outside air temperature is extremely low. The stable state continues,
Further, when the outside air temperature is extremely low, the intake density increases, so that the filling efficiency increases and causes abnormal combustion. In such a case, introducing the supercharging pressure into the combustion chamber promotes an unstable state of the engine and abnormal combustion. In addition, when the temperature is extremely low, malfunction of the electromagnetic control valve 69 itself may be considered, and the electromagnetic control valve 69 may not behave as instructed by the control means C. Therefore, when T _W <T _WL , the process proceeds to step S2 and D _OUT = 0.

When it is determined in step S5 that T _W ≧ T _WL or more, the process proceeds to step S6. Whether this step S6, the water temperature T _W is higher than the set high temperature T _WH is determined, setting high temperature T _WH
When exceeds, the process proceeds to step S2. Possible cases where T _W > T _WH are satisfied are, for example, when the engine continues to operate under high load, when the outside air temperature is extremely high, and when an abnormality occurs in the cooling water system of the engine body E. When there is. In all these states, the intake air density decreases, that is, the charging efficiency decreases, which causes abnormal combustion such as unburned combustion. Introducing the supercharging pressure into the combustion chamber when the engine is in the unstable state as described above promotes the unstable state, and therefore the duty ratio D _out = 0 is set in step S2. . In addition, when the pitch is extremely high, the inductance characteristic of the solenoid 70 is likely to change, and there is a risk that the behavior will be different from the setting behavior in the normal state. To avoid such a situation, the process proceeds to step S2. When it is determined in step S6 that T _W ≤T _WH , step S7
Proceed to. That process proceeds to step S7 when in the water temperature T _W is set low temperature T A at _WL or more as set high temperature T _WH the range, the process proceeds to step S2 otherwise.

In step S7, it is determined whether or not the supercharging pressure P ₂ exceeds a preset high supercharging pressure determination guard value P _2HG as shown in FIG. 7, and when P ₂ > P _2HG , the process _proceeds to step S2. If P _{2 ≤P 2HG} , the process proceeds to step S8. Here high boost pressure determination guard value P _2HG is to vary according to the engine rotational speed N _E, the maximum output in the following knock limit value of the advance amount of ignition timing corresponding to the engine speed N _E It is set to be obtained. Mainly due to the torque exerted transmission member at a low speed gear stage in the low speed range of the engine speed N _E, also becomes durable main cause of the engine body E in the high speed range, the lower P _2HG than the rotational speed range in each It is set. When the supercharging pressure P ₂ that exceeds the high supercharging pressure determination guard value P _2HG is detected, the duty ratio is set to 0% in step S4 after steps S2 and S3, and the supercharging pressure P ₂ is reduced.
Fuel injection is cut.

In step S8, the basic duty ratio D _M as the basic boost pressure control amount is searched. This basic duty ratio D _M is searched from the map according to the engine speed N _E and the throttle opening θ _TH . In this way, by searching the basic duty ratio D _M as the basic boost pressure control amount with the map determined by the engine speed N _E and the throttle opening θ _TH , each operating state of the engine can be accurately determined. it can. This is the engine speed N _E
This is because it is not possible to accurately determine the deceleration time or the transient operation state by itself or by the throttle opening θ _TH alone. Incidentally it employs a throttle opening theta _TH as a representative of a parameter indicating the load state of the engine, but in which the same effect can be obtained by alternative to the intake pressure P _B and the fuel injection amount.

In the next step S9, the shift position of the automatic transmission is set to the first position.
It is determined whether or not the vehicle is in the first speed position. When the vehicle is in the first speed position, the process proceeds to step S10, and when the vehicle is in a shift position other than the first speed position, the process proceeds to step S11.

In step S10, the basic duty ratio D _M is subtracted according to the subroutine shown in FIG. That is, the discrimination zone that needs to be reduced according to the operating condition determined by the engine speed N _E and the intake pressure P _B is preset as shown by the shaded area in FIG. 9, and it is discriminated whether or not it is within this discrimination zone. Whether or not to subtract the basic duty ratio D _M is determined depending on whether or not it is outside the zone. Meanwhile FIG. 9 in the engine speed N _E - is viewing a torque variation of the engine by the intake pressure P _B, the boundary line determination zone shows the maximum permissible torque of the gear shaft in the first speed position. That is, in order to prevent the force applied to the gear shaft from being overloaded in the first speed position, the judgment in each operating range is accurately made based on the engine speed N _E and the intake pressure P _B as shown in FIG. . When it is outside the discrimination zone, the basic duty ratio D _M is left as it is and the process proceeds to step S12. However, when it is in the discrimination zone, after it is judged whether the flag F is 0, that is, whether it is in the feedback control state, In the open control state, a subtraction of D _M = D _M −D _F is performed, and in the feedback control state, a subtraction of P _2REF = P _2REF −ΔP _2REFF is performed. Here, _DF is a preset subtraction value. Further, P _2REF is a target supercharging pressure used in the feedback control state, and ΔP _2REFF is a preset subtraction value, which will be described in detail later in the section of feedback control.

In step S11, the basic duty ratio D _M is subtracted according to the subroutine shown in FIG. That is, the throttle opening θ _TH exceeds the set throttle opening θ _THOS ,
Exceeded the engine speed N _E is the set rotational speed N _EOS, the intake pressure P _B exceeds the set intake pressure P _BOS, change rate .DELTA.N _E is positive in the previous engine rotational speed N _E, the current engine speed N _E when the rate of change .DELTA.N _E is negative, D _M = D _M -D _OS becomes subtraction is performed when in the open control state, P when it is in the feedback control state
_A subtraction of _2REF = _P2REF − _ΔP2REFOS is performed. In other _cases , the basic duty ratio D _M is left unchanged and the process proceeds to step S12. Here, D _OS and ΔP _2REFOS are preset subtraction values.

In step S12, it is determined whether the throttle opening θ _TH exceeds a preset throttle opening θ _THFB . The set throttle opening θ _THFB is set to determine whether to shift from open loop control to feedback control. By employing the throttle opening θ _TH as a determination parameter in this way, it is possible to accurately determine whether the driver is requesting acceleration, that is, a supercharging zone. When θ _TH ≦ θ _THFB, that is, when the open loop control is continued, in step S13, the delay timer t _FBDLY shown in FIG.
Is reset, and the process proceeds to step S14.

In step S14, the duty ratio correction coefficient K _MODij is searched from the map determined by the engine speed N _E and the intake air temperature T _A. This correction coefficient K _MODij is the optimum boost pressure P ₂ as described later.
Is learned within a predetermined deviation, and is updated at any time by the learning. Here, the initial value of the correction coefficient K _MODij is 1
Is.

In the next step S15, the atmospheric pressure correction coefficient K for duty ratio
_PATC (0.8-1.0) is determined corresponding to the atmospheric pressure P _A , and in the next step S16, the duty ratio intake air temperature correction coefficient K
_TATC (0.8 to 1.3) is determined corresponding to the intake air temperature T _A.
In step S17, the set subtraction value D _T according to the change rate ΔP ₂ of the supercharging pressure P ₂ is determined according to the subroutine of FIG.
That is, the throttle opening θ _TH is the set throttle opening θ
When larger than _THFB, Fig. 12 (a), (b),
Setting subtraction value D _T set by the supercharging pressure P ₂ of the change rate [Delta] P ₂ and the engine speed N _E as shown in (c) is selected, theta
_{When TH} ≤ θ _THFB , D _T = 0.

FIG. 12 (a) shows the set subtraction value D _T when the engine speed N _E is equal to or lower than the preset first switching speed N _FB1 (for example, 3000 rpm), and FIG. 12 (b) shows the engine. The set subtraction value D _T when the rotation speed N _E exceeds the first switching rotation speed N _FB1 and is equal to or less than the second switching rotation speed N _FB2 (for example, 4500 rpm) is shown.
FIG. 12 (c) shows the set subtraction value D _T when the engine speed N _E exceeds the second switching speed N _FB2 . Here, the set subtraction value D _T is the target boost pressure P _{2REF as} shown in FIG. 19 described later.
It is processed from when the actual boost pressure P ₂ exceeds the lower set value P _2ST and is for preventing overshoot at the rising of the boost pressure P ₂ . Moreover, D _T , the 12th
As shown in the figure and above, the engine speed N _E and the supercharging pressure change rate ΔP ₂ are set according to the engine speed N _E when the set value P _2ST is reached, and Pressure change rate ΔP ₂
This is because there is a difference in the amount of overshoot. Here, D _T is set to be larger as ΔP ₂ is larger and N _E is larger.

Further, in step S18, the set addition value D _TRB is determined according to the subroutine shown in FIG. That Figure 14 when the change rate [Delta] P ₂ of an open-loop control moreover the supercharging pressure P ₂ is a negative state (a), (b), (c)
As shown in, the set addition value D _TRB set by −ΔP ₂ and the engine speed N _E is selected, and the set subtraction value is further set.
D _T is set to 0. Further, in the feedback control state and when ΔP ₂ is positive, the set addition value D _TRB is set to 0.
This set addition value D _{TRB is} also the same as the above-mentioned set subtraction value D _{T according} to the engine speed N _E and the negative supercharging pressure change rate −ΔP ₂
It can be replaced as shown in the figure, and the larger N _E is,
It is set so that D _TRB increases as −ΔP ₂ increases, which enables duty ratio control such that stable supercharging pressure P ₂ with less hunting is obtained in each operating range. That is for example, from the start of acceleration to the predetermined region P _2ST movable vanes 5 as D _OUT = 100% as shown by a in FIG. 19
4 is set to a minimum gap flow area between the fixed vane 49 and the boost pressure P ₂ is increased with a large gradient to improve the acceleration performance of the engine, while the boost pressure P ₂ is set to the set pressure P _2ST . After exceeding the limit, by adding the set addition value D _TRB to prevent hunting that occurs as a reaction of the set subtraction value D _T for overshoot prevention, stable supercharging pressure control in each operating range is possible. is there.

After the correction coefficients K _MODij , K _PATC , K _TATC , the set subtraction value D _T, and the set addition value D _TRB are determined in this way, step
Proceed to S19.

In step S19, the duty ratio D _OUT is corrected by the following equation.

D _OUT = K _TATC × K _PATC × K _MODij × (D _M + D _TRB −D _T ) Further, in step S20, flag F = 1 is set to indicate the open loop control, and the duty ratio D _OUT is set in step S21. Check if the limit is exceeded. That is, the limit value of the duty ratio D _OUT is preset according to the engine speed N _E , and it is checked whether the duty ratio D _OUT is out of the limit value.If it is not out of the limit value, the duty ratio D _OUT is determined in step S4.
_OUT is output.

When it is determined in step S12 that θ _TH > θ _THFB , the process proceeds to step S22. In this step S22, it is determined whether or not the previous flag F is 1, that is, whether or not the previous time was the open loop control state, and F = 1.
In the case of, it is determined in step S23 whether or not the boost pressure P ₂ exceeds the duty control start determination _boost pressure P _2ST in the open loop. This duty control start determination boost pressure
P _2ST is obtained by P _2ST = P _2REF −ΔP _2ST , and ΔP _2ST is set according to the engine speed N _E as shown in FIGS. 15 (a), (b) and (c). There is. Where ΔP _2ST
The above-described D _T, similarly to the D _TRB, is intended to be set according to the engine rotational speed N _E and the supercharging pressure change rate [Delta] P ₂ so as to optimal duty ratio control, the engine speed N _E The bigger it gets,
Further, it is set so as to increase as the rate of change in supercharging pressure ΔP ₂ increases.

When P ₂ > P _2ST in step S23, it is determined in step S24 whether or not the boost pressure P ₂ exceeds the feedback control start determination _boost pressure P _2FB . This feedback control start determination supercharging pressure P _2FB is obtained by P _2FB = P _2REF −ΔP _2FB , and ΔP _2FB is shown in FIG. 16 (a), (b),
As shown in (c), it is set according to the engine speed N _{E. Like} ΔP _2ST , D _T , and D _TRB , ΔP _{2FB is} also determined according to the engine speed N _E and the supercharging pressure change rate ΔP ₂ in order to perform optimum duty control. It is set so that it increases as N _E increases and as the supercharging pressure change rate ΔP ₂ increases. In this step S24, P ₂ > P
_If it is _2FB , the process proceeds to step S25.

In step S25, it is determined whether or not the delay timer t _FBDLY has elapsed, and when it has elapsed, step S26
Proceed to. Also when was F = 0 in step S22 the process proceeds to step S26, bypassing step S23 to S25, to step S27 when at step S23 is P ₂ ≦ P _2ST, when at step S24 is P ₂ ≦ P _2FB is If the delay timer t _FBDLY has not elapsed in step S25, the process proceeds to step S13.

In step S27, the duty ratio D _OUT is set to 100, then in step S28 the timer t _FBDLY is reset and
Go to 4.

In step S26, it is determined whether or not the absolute value of the supercharging pressure change rate ΔP ₂ exceeds the feedback control determination supercharging differential pressure G _dp2 . This feedback control determination supercharging differential pressure G _dp2 is set to, for example, 30 mmHg, and when the absolute value of ΔP ₂ exceeds the feedback control determination supercharging differential pressure G _dp2 , the process returns to step S14, and the absolute value of ΔP ₂ is feedback controlled. When it is equal to or lower than the determination supercharging differential pressure G _dp2 , the process proceeds to step S29. If feedback control is started when | ΔP ₂ |> G _dp2 , hunting may occur, so
Returning to step S14, the open loop control is performed. As described above, in the open loop control, D _T ,
Since correction by D _TRB is performed to prevent hunting and overshoot, the main purpose of step S26 is to perform a fail-safe function.

The feedback control is started from step S29, and first, in step S29, the target supercharging pressure _P2REF preset by the engine speed N _E and the intake air temperature T _A is searched. Here, the feedback control is based on the premise that θ _TH > θ _THFB is first satisfied in step S12, and the engine speed N _E and the intake air are used as parameters that can accurately determine the operating state of the engine under these preconditions. temperature
The target boost pressure P _2REF determined by T _A is determined. Among θ _TH> θ _THFB i.e. engine, the engine speed N _E and the throttle opening theta _TH in the high-load state is intended to exhibit substantially the same behavior, N _E becomes valid parameter indicating the operating state of the engine Things. Further, the intake air temperature T _A is the intake air temperature on the downstream side of the intercooler 4 as shown in FIG. 1 and is a parameter that accurately indicates the intake state introduced into the combustion chamber. Therefore, by determining the target supercharging pressure P _{2REF based} on the map determined by the engine speed N _E and the intake air temperature T _A , it is possible to set a value that immediately corresponds to the operating state of the engine.

In the next step S30, the shift position of the automatic transmission is first.
It is determined whether or not the vehicle is in the fast position. When the vehicle is in the first speed position, in step S31, the calculation of P _2REF = P _2REF -ΔP _2REFF is performed according to the subroutine shown in FIG. 8 when the operating state is in the discrimination zone (hatched portion in FIG. 9). Then, the process proceeds to step S33. This ΔP _2REFF is a predetermined subtraction value applied when the shift position is at the first speed position. If it is determined in step S30 that the shift position is in a position other than the first speed position, step S32
In accordance with the subroutine shown in FIG.
_2REF = P _{2REF -ΔP 2REFOS} consisting operation is performed, step
Go to S33. Moreover, ΔP _2REFOS is a predetermined subtraction value applied when the shift position is in a state other than the first speed position.

In step S33, the supercharging pressure atmospheric pressure correction coefficient K _PAP2 and the duty ratio atmospheric pressure correction coefficient K are _calculated according to the atmospheric pressure P _A.
PATC is determined, and the next operation is performed in step S34.

P _2REF = P _2REF × K _PAP2 × K _{REFTB In the} above equation, K _REFTB is a correction coefficient corresponding to the knock state of the engine.

In step S35, the target supercharging pressure P _2ref and the present boost pressure P ₂
It is determined whether the absolute value of the deviation from and is greater than or equal to the set value G _P2 . The set value G _P2 is a dead zone defined pressure during feedback control is set to, for example, about 20 mmHg. When the absolute value of the deviation between the target supercharging pressure P _2REF and the actual supercharging pressure P ₂ is the set value G _P2 or more, the process proceeds to step S36.
When it is less than the set value G _P2 , the process proceeds to step S43.

In step S36, the proportional control term D _P of the duty ratio is calculated by the following equation.

D _P = K _P × (P _2REF −P ₂ ) In the above equation, K _P is a feedback coefficient related to the proportional control term, and is _calculated according to the subroutine shown in FIG. In FIG. 17, when the engine speed N _E is less than or equal to the first switching speed N _FB1 , K _P1 is obtained, and at the same time, a feedback coefficient K ₁₁ relating to an integral control term described later is obtained,
When the engine speed N _E exceeds the first switching speed N _FB1 and is less than or equal to the second switching speed N _FB2 , K _P2 and K ₁₂ are obtained, and the engine speed N _E is the second switching speed N N. _When it exceeds _FB2 , K _P3 , K
_I3 is obtained.

In step S37, as in step S14 described above, the correction coefficient K _MODij according to the engine speed N _E and the intake air temperature T _A is determined, and in step S38 it is determined whether or not the previous flag F is 1, that is, the first feedback control. It is determined whether or not the state is F. When F = 1, step S3
At 9, the previous integral control term D _{I (n-1)} is calculated according to the following equation.

D _{I (n-1)} = K _TATC x K _PATC x D _M x (K _MODij -1) After the completion of this calculation, the process proceeds to step S40, but step S38
When F = 0, the process bypasses step S39 and proceeds to step S40.

In step S40, the current integral control term D _In is calculated according to the following equation.

_{D In = D I (n-} 1) + K I + (P 2REF -P 2) Then, the duty ratio D _OUT is calculated in step S41. That is, an operation of D _OUT = K _TATC × K _PATC × D _M + D _P + D _In is performed, and after the flag F = 0 is set in step S42, the process proceeds to step S21.

Furthermore, in step S35, the target boost pressure P _2REF and the actual boost pressure
When the absolute value of the deviation from P ₂ is less than the set value D _P2 , D _P = 0 and D _In = D _{I (n-1)} are set in step S43. Next, in steps S44 to S47, whether the water temperature T _W is above a certain fixed range, that is, T _WMODL and less than T _WMODLH, whether the retard amount T _ZRET is 0, that is, is out of the knock state, the shift position is determined. It is determined whether or not the position is other than the first speed position and whether or not K _REFTB is 1.0 or less. If all of these conditions are satisfied, the process proceeds to step S48, and if any of these conditions is not satisfied, the process proceeds to step S41. .

In step S48, the coefficient K _R for learning the duty ratio correction coefficient K _MODij is calculated according to the following equation.

K _R = (K _TATC × D _M + D _In ) ÷ (K _TATC × D _M ) This coefficient K _R represents the deviation of supercharging pressure control due to variations due to mass production or aging.

Next, in step S49, in order to search and learn the correction coefficient K _MODij , Is performed, and in step S50, step S49
The K _MODij obtained in _{step 1} is stored.

Here, the K _MODij value of the second term on the right side is the learning correction coefficient obtained up to the previous time, and the engine speed N _E and the intake air temperature T _A
Is read from the K _MOD map described later. Further, A is a constant (for example, 65536), and C _MOD is a constant experimentally set to a suitable value among 1 to A.

Since the ratio of the K _R value to K _MODij changes depending on the value of the variable C _MOD , this C _MOD value is appropriate within the range of 1 to A according to the specifications of the target boost pressure control device, engine, etc. The optimum K _MODij can be obtained by setting the value to any value.

The learning correction value K _MODij calculated in this way is applied to the calculation of the duty ratio D _OUT for each region where the N _E value and the T _A value correspond to during open loop control, so it has a large effect on the boost pressure. The deviation of the boost pressure control described above can be accurately compensated in accordance with these engine parameters that give the control parameter, and the boost pressure control during the open loop control can be appropriately performed.

According to the duty control of the solenoid 70 in the electromagnetic control valve 69 as described above, when the shift position of the automatic transmission is at the first speed position and the open loop control state is established,
In step S10, the basic duty ratio D _M is subtracted by _DF when the engine is operating in the discrimination zone shown in FIG. 9, and in the feedback control state, the target boost pressure P _2REF is set in step S31 when the _engine is in the discrimination zone. Is ΔP _2REF
Is only subtracted. Therefore, when the shift position is the first speed position, it is possible to prevent an overload on the automatic transmission due to a sudden start, an overload, or the like by reducing the supercharging pressure as the basic duty ratio D _M decreases. Further, even if the control is shifted from the open loop control to the feedback control in the first speed position, the hunting can be prevented from occurring at the shift because the target boost pressure _P2REF is subtracted.

It is also assumed that the shift change shown in the lower part of FIG. 18 is performed. In this case, at the time of shift change,
While the engine speed N _E decreases, the operation of the actuator 60 by the control means C has a time lag. Therefore, the supercharging pressure P ₂ does not correspond to the engine speed N _E , and overshoot occurs, so that the supercharging pressure P ₂ is changed as shown by the broken line in FIG. Sometimes the limit may be exceeded. However, step S11
In step S32, the basic duty ratio D _M and the target boost pressure are calculated according to the subroutine shown in FIG.
Subtraction of _P2REF is performed. That is, at the time of shift change, the throttle opening theta _TH exceeds a predetermined value theta _THOS, exceeds a predetermined value N _EOS is the engine speed N _E, the intake pressure P _B is a predetermined value P _BOS
Is exceeded, that is, in accordance with the change rate ΔP ₂ of the supercharging pressure P _{2 in} the medium and high speed range, the basic duty ratio D _M is subtracted by D _{OS in} the open loop control, and the target supercharging pressure P 2 in the feedback control. _2REF is subtracted by ΔP _2REFOS . As a result, as shown by the solid line in FIG. 18, overshoot at the time of shift change can be significantly reduced, the occurrence of hunting phenomenon can be avoided, and stable supercharging pressure control can be performed.

Further, when shifting from open loop control to feedback control, it is possible to cover the drop in boost pressure P ₂ as shown in FIG. 19 and shift to feedback control promptly. That is, the duty ratio is
During the open loop control in which D _OUT is 0% and the throttle opening θ _TH is less than the set throttle opening θ _THFB , D _T = 0 is set according to the subroutine of FIG. 13 in step S18. When θ _TH > θ _THFB , the transition from open loop control to feedback control begins, but when the boost pressure P ₂ exceeds P _2ST , θ _TH > θ _THFB
Then D _M = D _M −D _T to prevent overshoot.

However, when only D _{T is} subtracted as described above, the boost pressure P ₂ may drop due to the reaction as shown by the broken line in FIG. However, if ΔP ₂ ≦ 0, D _T = 0, and only D _{TRB is} added, so that it is possible to cover the drop in the supercharging pressure P ₂ and quickly shift to feedback control.
The supercharging pressure control without the hunting phenomenon can be expanded.

The duty control of the solenoid 70 in the electromagnetic control valve 69 described above is performed in a state where the electromagnetic opening / closing valve 72 is closed. When the electromagnetic opening / closing valve 72 is opened, the second pressure chamber 63 in the actuator 60 is opened. The intake pressure P _B is supplied to the actuator 60, and the actuator 60 operates in the direction in which the movable vane 54 in the variable displacement turbocharger 5 increases the gap flow area between the movable vane 54 and the fixed vane 49.

Next, referring to FIG. 20, the solenoid of the solenoid on-off valve 72
The procedure in the control means C for controlling 73 will be described. Here, in addition to controlling the operation of the electromagnetic control valve 69 for introducing the boost pressure P ₂ into the first pressure chamber 62 of the actuator 60 based on the main routine of FIG.
By introducing the intake pressure P _B into the pressure chamber 63 via the electromagnetic opening / closing valve 72, more precise control becomes possible. This is supercharging pressure
P ₂ is variable capacity turbocharger 5 and intercooler 4
Since the minute operation of the throttle valve 74 cannot be detected because it is detected during the period, the intake pressure P _B is derived from the downstream side of the throttle valve 74, so the minute operation of the throttle valve 74 can be detected. Because it is. That is, the operation of the entire intake system including the turbocharger 5 is controlled by both the supercharging pressure sensor S _P2 that reliably detects the movement of the turbocharger 5 and the intake pressure sensor P _PB that reliably detects the movement of the throttle valve 74. It becomes possible to reflect it more accurately.

In step L1, the engine is started for a predetermined time, for example, 2
It is determined whether or not the minutes have elapsed, and when the predetermined time has not elapsed, the process proceeds to step L2, the solenoid 73 is excited, and the movable vanes 54 are moved by the actuator 60 in the direction of increasing the flow area between the movable vanes 54 and the fixed vanes 49. Operate. This is for coping with a cold start, supercharging pressure during cold is prevented, and the catalyst temperature can be gently raised. When the predetermined time has elapsed in step L1, the process proceeds to step L3, and it is determined whether the vehicle speed V exceeds the determination vehicle speed V _OP3 set with hysteresis, for example, _90/87 km / h, and V> V _OP3 Then step L4
And if V ≦ V _OP3 , proceed to step L5.

In step L4, it is determined whether the change rate Δθ _TH of the throttle opening is less than the set throttle opening change rate Δθ _THOP2 . This set throttle opening change rate Δθ _THOP2
Is set with hysteresis, and Δθ _TH <Δθ
When it is _THOP2 , the process proceeds to step L2, and otherwise, it proceeds to step L5.

In step L5, it is determined whether the vehicle speed V is less than the set vehicle speed V _OP1 . The set vehicle speed V _OP1 has a hysteresis and is set to, for example, 65/63 km / h. V
If> V _OP1 , the process proceeds to step L7, and if V ≦ V _OP1 , proceeds to step L6 to demagnetize the solenoid 73.
In step L7, it is determined whether the vehicle speed V exceeds the set vehicle speed V _OP2 . This set vehicle speed V _OP2 has a hysteresis and is set to, for example, 4/3 km / h. When V> V _OP2, the process proceeds to step L12, where V ≦ V _OP2
If it is, proceed to step L8.

In step L8, it is determined whether or not the previous vehicle speed V exceeds the set vehicle speed V _OP2 . When V> V _OP2 , the timer t _OP is reset in step L9 and then the process proceeds to step L10, and when V ≦ V _OP2. Go to step L10. In this step L10, it is determined whether or not the previous time was the excitation state, and when it is in the demagnetization state, the process proceeds to step L6, and when it is in the excitation state, it is determined in step L11 whether the timer t _OP exceeds the set time t _{OP0. Then} , when t _OP > t _OP0 , the process _proceeds to step L6, and when t _OP ≦ t _OP0 , the process proceeds to step L2.

In step L12, it is determined whether the engine speed N _E is less than the set speed N _EOP . This set speed N _EOP is
It has hysteresis, for example 2500 / 2300r
It is set to pm. Steps when N _E ≧ N _EOP
If L _E <N _EOP , then go to step L13.

At step L13, it is judged if the intake pressure P _B is less than the set intake pressure P _BOP . This set intake pressure P _BOP has hysteresis, for example, −100 / −150 mmHg
Is set to When P _B ≧ P _BOP , go to step L6,
If P _B <P _BOP , the process proceeds to step L14.

In step L14, it is determined whether the throttle opening θ _TH is less than the set throttle opening θ _THOP . The set throttle opening θ _THOP is set to, for example, _20/15 deg. When θ _TH ≧ θ _THOP , proceed to step L6, where θ _TH <
If θ _THOP , proceed to step L15.

Further, in step L15, the throttle opening change rate Δθ
It is determined whether _TH is positive and less than the set throttle opening change rate Δθ _THOP1 set with hysteresis, and if 0 <Δθ _TH <Δθ _THOP1 , go to step L2, or otherwise. Sometimes the process proceeds to step L6.

If such a procedure is completed, it is judged at step L3 and step L4 that 0 << when the vehicle speed exceeds 90 / 87km / h.
In the slow acceleration state in which Δθ _TH <Δθ _THOP2 , the movable vanes 54 of the variable displacement turbocharger 5 operate in the direction of increasing the gap flow area with the fixed vanes 49. Thereby, pumping loss can be prevented. That is, acceleration is not required in the cruising state at high vehicle speed, and operating the movable vane 54 on the boost pressure increasing side causes pumping loss due to rise in back pressure of the exhaust pipe caused by high engine speed. Because it does.

In step L5, the solenoid 73 is demagnetized when the vehicle speed exceeds 65/63 km / h. This is because the control of the solenoid control valve 69 shown in Fig. 5 is sufficient in such a high vehicle speed state. is there. Further, in steps L7 to L11, at a low vehicle speed of 4/3 km / h or less, that is, when the vehicle is almost stopped, the timer is reset when the previous vehicle speed is almost stopped, and the timer is reset, for example, for one minute. Exciting 73 causes the movable vanes 54 to operate so as to increase the flow area. This is to prevent that when the movable vanes 54 are on the side that reduces the flow area when restarting, the boost pressure P ₂ temporarily rises and overloads the starting gear, etc. is there. Furthermore, if the movable vane 54 is located on the side that reduces the distribution area when the vehicle speed is 4/3 km / h or less, the rotation of the variable capacity turbocharger 5 is promoted when the variable capacity turbocharger 5 is rotating due to inertia or the like. In that case, since the throttle opening θ _TH is almost fully closed, the supercharging pressure causes the intake passage internal pressure upstream of the throttle valve to rise. Therefore, by operating the movable vane 54 in the direction in which the flow area becomes large, the occurrence of surging due to the above-described pressure increase is prevented. Moreover, it can also contribute to the temperature rise of the catalyst immediately after starting in cold weather.

Depending on the judgment conditions of other steps L12 to L15, V _OP2
<V <V _OP1 , N _E <N _EOP , P _B <P _BOP , θ _TH <θ _THOP , 0 <Δ
When all of θ _TH <Δθ _THOP1 are satisfied, that is, in a slow acceleration state under partial load such as in 10 mode running, the solenoid 73 is excited to reduce the boost pressure P ₂ and thereby prevent pumping loss. be able to.

(Second Embodiment) FIG. 21 shows an electromagnetic control valve 69 according to a second embodiment of the present invention.
The control procedure of is shown. In the second embodiment, the supercharging pressure control is performed based on the intake pressure P _B detected by the intake pressure sensor S _PB without using the supercharging pressure sensor S _P2 .
This is because the boost pressure feedback control is the throttle valve 74
Is performed in an operating state in which the throttle valve 74 is almost fully opened, and that information about the supercharging pressure can be detected by the intake pressure P _B when the throttle valve 74 is almost fully opened.

First, in step S101, the basic duty ratio D _M is read from the D _M map according to the throttle valve opening θ _TH and the engine speed N _E. FIG. 22 shows an example of this D _M map, where the throttle valve opening θ _TH is within the predetermined range θ _THV1 ~ θ
_THV16 has 16-stage engine speed N _E within the specified range N _V1
To N _V20 as 20 stages, are respectively provided, the basic duty ratio D _M is determined by interpolation calculation in the non-grid points of the map. By setting the basic duty ratio D _M with such a map, the duty ratio D _OUT of the electromagnetic control valve 69 can be controlled in more detail according to the operating state of the engine E.

Next, it is determined whether or not the shift position of the transmission is at the first speed position (step S102). This determination is, for example, the 23rd
This is performed according to the subroutine shown in the figure. First, it is determined whether or not the vehicle speed V is lower than a predetermined speed V _L normally obtained at the first speed position, and when V <V _L is satisfied, the vehicle speed V is further decreased to a predetermined value V _F according to the engine speed N _E. Determine if it is less than. While it is determined that the shift position is not in the first speed position when V ≧ V _L or to V ≧ V _F is satisfied, V <V _L and V
When both <V _F are satisfied, it is determined that the shift position is in the first gear position.

FIG. 24 shows a table for obtaining the predetermined value V _F. That is, when the shift position is in the first speed position, there is a relationship in which the ratio between the engine speed N _E and the vehicle speed V is constant, so that the reference value N _F1 of the engine speed N _E should match this relationship. ~ N _F9 and reference values V _{F1 to} V _F8 of the vehicle speed V are set in advance as a table, and the vehicle speed V is the actual engine speed.
When it is smaller than the reference value V _F corresponding to N _E , it is determined that the vehicle is in the first speed position. With such a configuration, it is possible to determine whether the shift position is the first speed position without using a shift position sensor or the like not only when the transmission is a manual transmission but also when it is an automatic transmission. It can be done easily.

Returning to FIG. 21, the shift position is set to the first position in step S102.
If it is determined that the vehicle is in the fast position, then step S101
By subtracting a predetermined value D _F from the basic duty ratio D _M obtained in, and re-set the basic duty ratio D _M (step S103),
Proceed to step S104. When the shift position is a position other than the first speed, the process directly proceeds to step S104. in this way,
The basic duty ratio D _M is a predetermined value D _F when the shift position is in the first gear position than when it is in a position other than the first gear position.
Is set to a small value.

In step S104, the engine speed N is calculated from the K _TATC map.
Intake temperature correction coefficient K _TATC is read according to _E and intake temperature T _A. FIG. 25 shows an example of the K _TATC map, the engine rotational speed N _E wherein D _M map as well as N _V1 to N _V20 as 20 stages, the intake air temperature T _A is 8 phase as T _AV1 through T _AV8, respectively The intake air temperature correction coefficient is provided by such a map.
K _TATC is set more appropriately.

Next, the rate of change of intake pressure P _B (hereinafter, simply referred to as “rate of change”) ΔP _B is calculated from the difference between the current value P _Bn and the value P _Bn-3 three times before (step S105). This rate of change ΔP _B is applied to set various constants for calculating the duty ratio D _OUT, as will be described later, whereby the rising gradient of the supercharging pressure is controlled to a desired value. .

Next, in step S106, it is determined whether or not the boost pressure is in a state where open loop control should be performed. This determination is performed according to the subroutine shown in FIG.

First, in step S201, it is determined whether or not the throttle valve opening θ _TH is larger than a predetermined opening θ _THFB indicating that the throttle valve opening θ _TH is in a substantially fully opened state. When θ _TH ≦ θ _THFB is satisfied and the throttle valve 74 is not in the fully open state, it is determined that the open loop control should be performed, and the process proceeds to step S216 and later described later. That is, the feedback control is executed only when the throttle valve 74 is in the fully open state.

When θ _TH > θ _THFB is satisfied in step S201, it is determined whether or not the flag F set in step S203 or S221 described later in the previous loop is equal to the value 1, that is, whether open loop control is performed ( Step S20
2).

When the feedback control was performed last time, it is determined that the feedback control should be continuously performed, the flag F is set to the value 0 (step S203), and this program is ended.

When it is determined in step S202 that the open loop control was previously performed, it is determined whether or not the shift position is at the first speed position (step S204). When the shift position is a position other than the first speed, a first subtraction value ΔP _BST is obtained from the ΔP _BST table for positions other than the first speed according to the change rate ΔP _B (step S205), which will be described later. It proceeds to step S207. FIG. 27 shows an example of this ΔP _BST table, which shows two reference values ΔP _B1 and ΔP _B2 for the rate of change ΔP _B.
(> ΔP _B1 ) is set, and ΔP _BST3 to ΔP _BST1 are set so that the first subtraction value ΔP _BST becomes larger as ΔP _B becomes larger, that is, as the rising gradient of the boost pressure increases. .

When it is determined in step S204 that the shift position is in the first speed position, the first subtraction value ΔP _BST is set to the predetermined value ΔP _BSTF for the first speed position (step S206), and the process proceeds to step S207. . The predetermined value ΔP _BSTF is _obtained in the step S
In 205, it is set to a value larger than the ΔP _BST value obtained from the ΔP _BST table for positions other than the first speed.

Next, at step S207, the intake pressure P _B is the difference (P _BREF −Δ) between the target value (target supercharging pressure) P _BREF and the first subtraction value ΔP _BST obtained at step S205 or S206.
P _BST ) (hereinafter referred to as “duty control start determination pressure”). Target value of intake pressure P _BREF
As will be described later, is set according to the engine speed N _E , the intake air temperature T _A, and the shift position in the control program of FIG.

In this step S207, when it is determined that the intake pressure P _B is less than or equal to the duty control start determination pressure (P _BREF −P _BST ), both the proportional control term D _P and integral control term D _I applied to feedback control, which will be described later, are set. Set the value to 0.0 (steps S208, S20
9) Next, the duty ratio D _{OUT is set} to 100%, that is, the movable vane 54 is set to the minimum opening (step S21).
0). That is, when P _B ≦ (P _BREF −ΔP _BST ) is satisfied, the minimum opening control of the movable vane 54 is executed (see FIG. 35).
(between t _{0 and} t _A ), this control maximizes the rising gradient of boost pressure on the low boost pressure side, and boost pressure is increased by speeding up boost pressure to near the desired pressure value. Responsiveness is enhanced.

Next, the t _FBDLY timer for delaying the feedback control is reset (step S211), the process proceeds to step S118 in FIG. 21, and the drive signal based on the duty ratio D _OUT is transferred to the electromagnetic control valve 69.
To end the control program shown in FIG.

Returning to the subroutine of FIG. 26, in step S207,
The intake pressure P _B is the duty control start determination pressure (P _BREF −Δ
If it is determined that P _BST is exceeded, it is determined whether or not the shift position is at the first speed position (step S212). When the shift position is a position other than the first speed, a second subtraction value ΔP _BFB is obtained from the ΔP _BFB table for positions other than the first speed according to the change rate ΔP _B (step S213), which will be described later. Proceed to step S215. Figure 28 shows an example of the [Delta] P _BFB table, just as the rate of change [Delta] P _B value becomes larger as the FIG. 27, so as to increase the second subtraction value [Delta] P _BFB Gayori, ΔP _BFB3 ~ΔP _BFB1 (ΔP _BFB3 <ΔP _BFB2 <ΔP _BFB1 )
Is set.

When it is determined in step S212 that the shift position is at the first speed position, the second subtraction value ΔP _{BFB is set} to the first value.
Set to a predetermined value ΔP _BFBF for fast position (step S214),
Proceed to step S215. The predetermined value ΔP _BFBF is set to a value larger than the ΔP _BFBF value for positions other than the first speed, which is obtained in step S213.

Next, in step S215, the intake pressure P _B is set to the target value.
P _BREF and the second obtained in step S213 or S214
_Is smaller than the difference (P _BREF −ΔP _BFB ) (hereinafter referred to as “feedback control start determination pressure”) from the subtracted value ΔP _BFB (step S215). When the intake pressure P _B is equal to or lower than the feedback control start determination pressure (P _BREF −ΔP _BFB ), it is determined that the open loop control should be performed, and the process proceeds to step S216 and thereafter. That is, (P _BREF −ΔP _BFB ) <P _B ≦
When (P _BREF −ΔP _BFB ) is established, open loop control is executed (between t _A and t _{B in} FIG. 35).

In this step S216, t
_{The FBDLY} timer is reset, and then it is determined whether or not the shift position is at the first speed position (step S217). When the shift position is other than the first speed position, the subtraction term D _T applied to the open loop control is obtained from the D _T table for positions other than the first speed according to the change rate ΔP _B (step S21
8) and proceeds to step S221 described later. FIG. 29 shows an example of this D _T table. Just like FIG. 27, the subtraction term D _T becomes larger as the rate of change ΔP _B becomes larger, and D _T1 ~ D
_T3 (D _T1 <D _T2 <D _T3 ) is set.

When it is determined in step S217 that the shift position is at the first speed position, the subtraction term D for the first speed position is calculated from the _DFT table for the first speed position according to the change rate ΔP _{B.
Find FT} (step S219). FIG. 30 shows an example of this D _FT table, which shows two reference values P _BF1 for the rate of change ΔP _B.
And ΔP _BF2 (> ΔP _BF1 ) are set, and as the ΔP _B value increases, the subtraction term D _FT for the first speed position increases so that D
_{FT1 to} D _FT3 (D _FT1 <D _FT2 <D _FT3 ) are set. Further, the D _FT table is set so that the subtraction value becomes larger for the same ΔP _B value as compared with the D _FT table.

Next, the subtraction term D _T is set to the obtained D _FT value (step S220), and in step S221 the flag F is set to a value 1 to indicate that open loop control should be executed. Exit the program.

When it is determined in step S215 that the intake pressure P _B exceeds the feedback control start determination pressure P _BREF −ΔP _BFB ), the predetermined time t _FBDLY has elapsed after the t _FBDLY timer was reset in step S211 or S216. It is determined whether or not (step S222). When the predetermined time t _FBDLY has not elapsed, the process proceeds to step S217 to perform the open loop control, while when the predetermined time t _FBDLY has elapsed, it is determined that the feedback control should be performed, and the process proceeds to step S223. As described above, when the intake pressure P _B exceeds the feedback control start determination pressure P _BREF −ΔP _BFB ), the feedback control is not performed immediately, but the open loop control is _performed from this time until the predetermined time t _FBDLY elapses. It is executed (between t _B and t _{C in} FIG. 35), and feedback control is executed only after the elapse (after t _{C in the} same figure).

In step S223, the initial value of the integral control term D _I is calculated according to the following equation.

D _I = K _TATC × D _M × (K _MODij −1) Here, K _MODij is a learning correction coefficient (learning value) calculated at the time of feedback control as described later according to the program of FIG.

Next, in step S203, the flag F is set to 0 to indicate that feedback control should be performed.
Set to and exit this program.

Returning to the program of FIG. 21, in step S107 following step S106, it is determined whether or not the flag F set in the subroutine of FIG. 26 executed in step S106 is equal to the value 1. When it is determined that the flag F = 1, that is, the feedback control should be performed, the target value P _BREF of the intake pressure is read from the P _BREF map according to the engine speed N _E and the intake temperature T _A (step S108). . No. 31
The figure shows an example of this P _BREF map, and just like the K _TATC map, the reference values N _{V1 to} N _V20 of the engine speed N _E and the reference values T _{AV1 to} T _{AV8 of the} intake air temperature T _A are set. Therefore, the target value P _BREF can be set more appropriately by such a map.

Next, in step S109, it is determined whether or not the shift position is at the first speed position. When the shift position is in the first speed position, the predetermined value P _BREFF is subtracted from the target value P _BREF obtained in step S108 (step S110) to obtain the target value P _BREF.
Is reset and the process proceeds to step S111. When the shift position is a position other than the first speed, the process directly proceeds to step S111.
In this way, the target value P _BREF is _higher when the shift position is at the first speed position than when it is at a position other than the first speed position.
It is set to a value smaller by a predetermined value P _BREFF .

By setting the target value P _BREF like this, the transmission is set to the first position.
When in the speed position, the supercharging pressure in the steady state can be controlled to a smaller value to suppress the torque applied to the gear, so that the durability can be improved, and at the positions other than the first speed, the steady state can be achieved. In the state, a higher desired supercharging pressure can be obtained.

In this step S111, the deviation ΔP _BD between the target value P _BREF set in step S108 or S110 and the actual intake pressure P _B
(= P _BREF -P _B) is calculated, then the absolute value of the deviation ΔP _BD | ΔP _BD | it is determined whether or not a predetermined value G _PB (e.g. 20 mmHg) or more (step S112). This predetermined value G _PB is the dead zone defining pressure during feedback control.

When | ΔP _BD | ≧ G _PA is satisfied in step S112, the engine speed is determined from the K _P table and the K _I table.
According to N _E , the constants of the proportional control term D _P and the integral control term D _I
Each of K _P and K _I is read (step S113). 32 and 33 are views showing examples of the K _P table and the K _I table, respectively. That is, in the K _P table, there are two reference values N _FBP1 and N _F for engine speed N _E.
FBP2 (> N _FBP1 ) is set, the constant K _P is less than N _FBP1 , N
Against _FBP1 or N _FBP2 less and N _FBP2 above, respectively K
_{P1 ~K P3 (K P1 <K} P2 <K P3) is set to. In the K _I table, there are two reference values for the engine speed N _E.
N _FBI1 and N _FBI2 (> N _FBI1 ) are set, and the constant K _I is N
Less than _FBI1, against N _FBI1 more than N _FBI2 and N _FBI2 above, are each set to _{K I1 ~K I3 (K I3 <} K I1 <K I2).

Next, the proportional control term D _P is set to the product K _P × ΔP _BD of the constant K _P obtained above and the deviation ΔP _BD (step S114),
The integral control term D _I is calculated using the constant K _I obtained above and the deviation ΔP.
The product of _BD , K _I × ΔP _BD, and the integral control term D calculated up to the previous time
The sum of the _I (= set to _{D I + K I + ΔP BD} ( step S11
Five).

Then, applying the proportional and integral control terms D _P and D _I set above, the duty ratio D during feedback control is applied.
_OUT is calculated according to the following equation (step S116).

D _OUT = D _M × K _TATC + D _P + D _I Next, a limit check of the calculated duty ratio D _OUT is performed to hold the duty ratio D _OUT within a predetermined range (step S117). A drive signal based on the duty ratio D _OUT is output to the electromagnetic control valve 69 (step S1
18) Exit this program.

In step S112, when | ΔP _BD | <G _PB holds, and therefore the target value P _BREF and the actual intake pressure P _B substantially match, the proportional control term D _P is set to 0.0 and the integral control term D _I is set to its previous value D _I respectively (steps S119, S12
0).

Next, it is determined whether or not the shift position is in the first speed position (step S212), and when it is in a position other than the first speed,
The coefficient K _R is calculated according to the following equation (step S122).

Next, the learning correction coefficient K _MODij is calculated using the coefficient K _R according to the K _MODij calculation formula in the first embodiment described above. (Step S123).

Then, the calculated learning correction coefficient K _MODij is stored in the K _MOD map provided in the backup RAM in the control means C (step S124), and the steps S116 _{et seq. Are} executed and the program is terminated. FIG. 34 shows an example of this K _MOD map. That is, the K _MOD map is the K _TATC map (second
(Fig. 5) and P _BREF map (Fig. 31) are _divided into multiple regions by the engine speed N _E and intake air temperature T _A , and the K _MODij value of each region is _divided by N _E value and T _A value. Calculation and storage are performed.

In step S107, the flag F = 1 is satisfied, that is,
When it is determined by the subroutine of FIG. 26 that open loop control should be performed, the learning correction coefficient K is determined from the K _MOD map according to the engine speed N _E and the intake air temperature T _A.
Read _MODij (step S125), then proportional control term D
Set both _P and the integral control term D _I to the value 0.0 (step
S126, S127).

Next, the duty ratio D during open loop control
_OUT is calculated according to the following equation (step S128).

D _OUT = K _TATC × K _MODij × (D _M −D _T ) Here, D _T is the subtraction term set in step S218 or S220 of the subroutine of FIG.

Next, a limit check of the calculated duty ratio D _OUT is performed, for example, the D _OUT value is held at a value of 0% or more and 100% or less (step S129), the step S118 is executed, and the program ends. To do.

As described above, the learning correction coefficient K _MODij is calculated and stored for each region where the engine speed N _E and the intake air temperature T _A are in the feedback control, and the N _E value and the T _A value are in the open loop control. Is applied to the calculation of the duty ratio D _OUT for each applicable region. Therefore, the above-mentioned deviation of the boost pressure control can be accurately compensated in accordance with these engine parameters that have a great influence on the boost pressure, and the boost pressure control during the open loop control can be appropriately performed.

When it is determined in step S121 that the shift position is in the first speed position, the process directly proceeds to step S116 and _thereafter , and the calculation of the learning correction coefficient K _MODij is stopped. As described above, when the shift position is in the first gear position, the target value P _BREF is the predetermined value P _BREF more than in the other shift positions.
_{The BREFF} is set to a small value (step S210), and accordingly, the supercharging pressure state changes even when the engine speed N _E and the intake air temperature T _A are in the same region. Therefore,
As described above, when the shift position is in the first gear position, K
_By stopping the calculation of the _MODij value, it is possible to prevent the K _MODij value from deviating from an appropriate value, and thus it is possible to more appropriately control the boost pressure during open loop control.

(Third Embodiment) FIGS. 36 and 37 show a third embodiment of the present invention. Compared with the second embodiment described above, this embodiment uses scramble / boost control according to the control program of FIG. 36, that is, the target value of the supercharging pressure is set to improve the acceleration performance when the engine is in a predetermined acceleration state. The only difference is that the control is performed to increase by a predetermined value, and accordingly, only the execution content corresponding to step S121 in FIG. 21 is different, and the other execution content is exactly the same.

FIG. 36 shows a flow chart of a control program for controlling the execution of the scramble boost.

First, similarly to step S201 of FIG. 26, it is determined whether or not the throttle valve opening θ _TH is larger than the predetermined opening θ _THFB (step S301), and θ _TH ≦ θ _THFB is established, that is, the throttle valve When the 74 is not almost fully open, flag F
_TCUP is set to the value 0 (step S302), and this program ends.

When θ _TH > θ _THFB is satisfied in step S301, it is determined whether or not the flag F _TCUP is 1 (step S303). This flag F _TCUP indicates that the engine cooling water temperature T _W is _{equal to} or lower than a predetermined temperature T _WTCUP and the engine speed N _E is within a predetermined speed range when the engine is operating in a predetermined acceleration state. The value is set to 1 in step S307 described later.

When F _TCUP = 0 is established in the step S303, and thus the predetermined acceleration state is not established in the previous loop, it is determined whether or not the engine cooling water temperature T _W is higher than the predetermined temperature T _WTCUP (step S304). ). When T _W ≦ T _WTCUP is established, the process proceeds to step S305.

In this step S305, it is determined whether or not the engine speed N _E is higher than the first predetermined speed N _TCUP1 (eg, 2,500 rpm), and when N _E > N _TCUP1 is satisfied, the engine speed N _E is further increased.
It is determined whether N _E is _higher than a second predetermined rotation speed N _TCUP2 (eg, 4,000 rpm) which is higher than the first predetermined rotation speed N _TCUP1 (step S306). As a result, N _TCUP1 <N _E ≤ N _TCUP2
When is satisfied, it is determined that the engine is in a predetermined acceleration state, and the flag F _TCUP is set to the value 1 as described above (step S307).

Next, the t _TCUP timer is set to an initial value of 0 and started (step S308), and the step
Proceed to S309. If F _TCUP = 1 is satisfied in step S303, the process directly proceeds to step S309.

In this step S309, it is judged whether or not a predetermined time t _TCUP (for example, 10 seconds) has elapsed since the t _TCUP timer was started, and when t _{TCUP has} elapsed, a step S311 described later is performed.
This program ends without executing.

In the steps S304 to S306, T _W >
When T _WTCUP or N _E ≤N _TCUP1 or N _E ≤N _TCUP2 is satisfied, that is, when it is determined that the engine is not in the predetermined acceleration state described above, the t _TCUP timer is reset (step S
310), the program ends.

When it is determined in step S309 that the predetermined time t _TCUP has not elapsed since the t _TCUP timer started, the target value P _BREF obtained in step S108 in FIG. 21 is set to the predetermined value ΔP _TCUP (for example, 50 mmHg). _Is added to the new P _BREF
The value is reset (step S311), and this program ends.

Therefore, when the throttle valve opening θ _TH > θ _THFB is satisfied, a predetermined time t _TCUP elapses after the operating state of the engine enters a predetermined acceleration state, or before the predetermined time t _TCUP elapses. When the operating state of the engine deviates from the predetermined acceleration state, until step S3
11 is executed, and the target boost pressure P _BREF value is the predetermined value ΔP
_The value is increased by the _TCUP value, and based on the increased P _BREF value, the control program of step S109 and _{thereafter in} FIG. 21 and the control program in FIG. 26 are executed. This improves the acceleration performance of the engine.

FIG. 37 shows a part of the control program similar to that of FIG. 21 of the second embodiment, and shows only the part of the execution contents different from FIG. That is, in step S121 ′ corresponding to step S121 in FIG. 21, it is determined whether or not scramble / boost control is being executed, and when scramble / boost control is not being executed, learning is performed by executing step S122 and subsequent steps. The correction coefficient K _MODij is calculated. On the other hand, when the scramble / boost control is being performed, the process directly proceeds to step S116 and _thereafter , and the calculation of the learning correction coefficient K _MODij is stopped.

During scramble boost control, as described above,
Target value of boost pressure P _BREF is a predetermined value ΔP _TCUP
Therefore, as with the case where the shift position is at the first speed position in the second embodiment, by stopping the calculation of the learning correction coefficient K _MODij during the control,
The deviation of the K _MODij value can be prevented, and the boost pressure can be controlled more appropriately during open loop control.

Although the variable capacity turbocharger in which the movable vanes 54 are operated to change the capacity is taken up and described in the above first to third embodiments, the present invention is not limited to the wastegate method and the supercharging pressure relief method. It is also applicable to capacity turbochargers.

(Effects of the Invention) As described in detail above, the present invention has the following effects.

According to the first aspect, the target boost pressure state is set to a value different from the normal value under a predetermined condition such that the boost pressure state changes, so that learning to an appropriate value is performed even if the boost pressure state changes. The deviation of the value can be prevented, and the supercharging pressure in the transient state can be appropriately controlled.

Further, according to Claims 2 and 3, the above effect is obtained when the target supercharging pressure is set to a value different from the normal value due to the change of the gear position or the engine being in a predetermined acceleration state. be able to.

[Brief description of drawings]

1 is an overall schematic view showing an intake system and an exhaust system of an internal combustion engine, FIG. 2 is an enlarged vertical side view of a variable capacity turbocharger, FIG. 3 is a sectional view taken along line III-III of FIG. 2, and FIG. Is the second
Fig. 5 is a sectional view taken along the line IV-IV in Fig. 5, Fig. 5 is a flowchart showing a main routine for controlling the electromagnetic control valve, and Fig. 6 is a flowchart showing a subroutine for timer selection.
FIG. 7 is a graph showing a high boost pressure determination guard value, FIG. 8 is a flowchart showing a subroutine for subtracting the reference duty ratio and the target boost pressure at the first speed position, and FIG. 9 is a subroutine of FIG. FIG. 10 is a view showing a discrimination zone to be used, FIG. 10 is a flow chart showing a subroutine for subtracting the basic duty ratio and the target supercharging pressure at positions other than the first speed position, and FIG.
FIG. 12 is a diagram showing a map of set subtraction values, FIG. 13 is a flowchart showing a subroutine for determining set addition values,
Figure 14, flowchart Figure 15 and FIG. 16 showing a subroutine for determining a D _TRB, [Delta] P _2ST, shows each setting map of [Delta] P _2EB, feedback coefficients Figure 17 is according to the proportional control term and the integral control term Fig. 18 is a diagram showing changes in intake pressure during a shift change, Fig. 19 is a diagram showing changes in duty ratio and supercharging pressure during transition from open loop control to feedback control, and Fig. 20 is an electromagnetic switching 21 to 35 show a second embodiment of the present invention, and FIG. 21 shows a main routine for controlling an electromagnetically controlled valve, and FIG. 22 shows a main routine for controlling the valve. The figure shows the map of basic duty ratio D _M ,
FIG. 23 is a flowchart of a subroutine for determining the gear position of the transmission, FIG. 24 is a view showing a V _F table applied to the subroutine of FIG. 23, and FIG. 25 is an intake air temperature correction coefficient K.
Figure showing the _TATC map, Figure 26 shows step S106 in Figure 21.
FIG. 27 is a flow chart of the open-loop control area discrimination subroutine executed in FIG. 27, FIG. 27 shows a table for positions of the first subtraction value ΔP _BST other than the first speed, and FIG.
Of the subtraction value ΔP _BFB for positions other than the first speed, FIG. 29 is a table for positions of the subtraction term D _T other than the first speed, and FIG. 30 is for the positions of the first speed. Fig. 31 shows a table of subtraction term D _FT , Fig. 31 shows a map of target value P _BREF of supercharging pressure, Fig. 32 shows a table of constant K _P of proportional control term D _P , Fig. 33 Shows a table of constants K _I of integral control term D _I , FIG. 34 shows a map of learning correction coefficient K _MOD , 35
Figure shows the relationship between intake pressure P _B and supercharging pressure control, Figure 36 is a flowchart of a program that controls the execution of scramble boost, and Figure 37 is the main part of a flowchart of a program similar to Figure 21. FIG. E ... internal combustion engines, S _P2 ... supercharging pressure (P ₂₎ sensor, S _PB ... intake pressure (P _B) sensor, S _N ... engine speed (N _E) sensor,
S _V ... Vehicle speed (V) sensor, S _W ... Engine cooling water temperature (T _W ) sensor, 5 ... Variable capacity turbocharger, 69 ... Electromagnetic control valve (supercharging pressure control means)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-62-153523 (JP, A) JP-A-61-169625 (JP, A) JP-A-62-276223 (JP, A) Actual development Sho-59- 67533 (JP, U)

Claims (5)

(57) [Claims] 1. An internal combustion engine for controlling a boost pressure by controlling a control amount for operating a boost pressure control means, the control amount being corrected by a correction value depending on at least one engine operating parameter. In a supercharging pressure control method, a feedback control step of controlling the control amount according to a deviation between an actual supercharging pressure and a target supercharging pressure; and a correction value applied during the feedback control step. A learning value calculation step for obtaining the learning value of the correction value by the above, an open control step for open-controlling the control amount based on the learning value of the correction value calculated in the learning value calculation step, and A selection step of selecting the feedback control step and the open control step, and the target supercharging pressure during the feedback control step is normal time and when a predetermined condition is satisfied. A target supercharging pressure setting step of setting different target supercharging pressures; and a learning value calculation prohibiting step of prohibiting calculation of the learning value in the learning value calculation step when the predetermined condition is satisfied. For controlling supercharging pressure of internal combustion engine. 2. In the step of setting the target supercharging pressure, when the transmission of the engine is at a predetermined low speed position, the predetermined condition is set, and as the target supercharging pressure, the transmission is at a position other than the predetermined low speed position. The method for controlling the supercharging pressure of an internal combustion engine according to claim 1, wherein a value smaller than the value set when the vehicle is in the position is set. 3. In the target supercharging pressure setting step, when the engine is in a predetermined acceleration state, the predetermined condition is set, and the target supercharging pressure is set to a value larger than when the engine is not in a predetermined acceleration state. The method for controlling supercharging pressure of an internal combustion engine according to claim 1, wherein the setting is performed. 4. The supercharging pressure control of an internal combustion engine according to claim 3, wherein the predetermined acceleration state is an acceleration state in which the engine cooling water temperature is lower than a predetermined value and the engine speed is within a predetermined range. Method. 5. The internal combustion engine according to claim 3, wherein the setting of the large value as the target supercharging pressure ends when a predetermined time has elapsed after the engine entered a predetermined acceleration state. Supercharging pressure control method.