JPH0520565B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a boost pressure control device for a turbocharger.

(Conventional technology) A turbocharger uses the high temperature and high pressure energy of exhaust gas to rotate an exhaust turbine at high speed and drive a compressor located on the same axis. can raise the pressure above atmospheric pressure. Such boost pressure makes it possible to supply a large amount of intake air to the engine, resulting in higher torque, higher output, and improved fuel efficiency.

However, in the case of automobile engines with a wide rotation speed range, although it is possible to secure sufficient boost pressure in the medium and high speed operating range, it is difficult to obtain sufficient exhaust pressure in the low speed operating range, so it is necessary to draw out the boost pressure. However, low-speed torque tends to be insufficient. In this case, what determines the supercharging pressure in the low-speed operating range can be expressed as the ratio A/R of the cross-sectional area A of the scroll section and the radius R from its center. If it is possible to do so, it is possible to increase the turbine rotation speed and accelerate the rise in boost pressure. Therefore,
The present applicant has filed an application for a variable displacement turbocharger in which the turbocharger is equipped with a displacement variable means for varying the A/R of the turbine (patent application
58-162918), this variable displacement turbocharger can provide sufficient boost pressure even in low speed operating ranges.

To explain supercharging pressure control using this turbocharger, an actuator is provided that uses the supercharging pressure generated downstream of the compressor as operating pressure to drive the capacity variable means of the turbocharger, and controls the duty of a solenoid valve that releases this operating pressure to the outside. By doing so, the A/R of the turbine is variably controlled to quickly increase the boost pressure. Figure 9A
is the control characteristic of such a solenoid valve, where the horizontal axis shows the intake air amount and the vertical axis shows the value of the basic control duty. This duty represents the valve opening time per predetermined time, and when the duty is 100%, it means that the solenoid valve is fully open.
is minimized and the turbine rotation speed is increased. Further, when the duty is 0%, the solenoid valve is fully closed, and in this case, A becomes maximum and the turbine rotational speed is suppressed. In this way, the supercharging pressure is quickly increased, and thereafter, the supercharging pressure is controlled to a constant value by using the exhaust bypass valve to control the bypass flow rate of the exhaust gas to the outside of the turbine. In actual control, feedback control is performed based on the actual detected value in order to eliminate control deviations due to various variation factors, and in this example, the actual boost pressure detected by the boost pressure sensor and A feedback correction amount is determined from the deviation from the target boost pressure, and the basic control duty is corrected using this value.

(Problem to be Solved by the Invention) In this way, if feedback control is performed only for control by the variable capacity means, even if control accuracy can be improved in the control range of the variable capacity means, there will be variations in the setting of the exhaust bypass valve. If so, control accuracy will be impaired in the control region on the exhaust bypass valve side. On the other hand, if the plurality of control means are simply subjected to feedback control in order to improve the control accuracy on the exhaust bypass valve side, the plurality of control means interfere with each other, making it impossible to perform suitable control. For example, when the capacity variable means moves from the optimum position to the closed side, the exhaust bypass valve moves from the optimum position to the open side, and the overall boost pressure is maintained at the target value. However, in order to maximize the engine's performance, there is an optimal position for the variable capacity means and the exhaust bypass valve, and when the engine deviates from this position, the turbine capacity becomes small and the engine output decreases. .

Therefore, whether feedback control is to be performed by the variable capacity means or by the exhaust bypass valve is divided into predetermined operating ranges in advance, and the control of multiple control means is switched based on the results of determining these operating ranges from the actual operating conditions. Inconveniences caused by control interference can be avoided by selectively performing feedback control of the boost pressure on one of them at all times and keeping the other fixed.

By the way, in order to improve acceleration performance, it is effective to perform overboost control that temporarily increases the target boost pressure during sudden acceleration to obtain high boost pressure and improve engine output. If it is adopted as it is for boost pressure control that avoids interference between multiple controls, control will switch from the capacity variable means side to the exhaust bypass valve side during overboost control, and the exhaust bypass valve will be closed. Even when fully closed, if the turbine capacity is large, it may not be possible to obtain the target supercharging pressure during overboost control. That is, when sudden acceleration is performed and overboost control is performed, the target supercharging pressure is increased to a high target supercharging pressure during overboost control. In order to obtain this high target boost pressure, as mentioned above, it is necessary to increase the control duty on the capacity variable means side and reduce the opening degree of the capacity variable means (move to the closing side), but especially when the load is high, In the case of sudden acceleration from , the operating range is reached where the control is switched during overboost control, and the control is switched to the exhaust bypass valve side, so the control duty on the capacity variable means side after switching becomes small. . With this small control duty, instead of keeping the opening degree of the variable displacement means small, the opening degree of the variable displacement means is increased, making it difficult to obtain a high target supercharging pressure during overboost control.

This invention was made with attention to these problems, and it is a supercharging system that can obtain a high boost pressure as a target during overboost control without reducing engine output even when overboost control is performed. The object of the present invention is to provide a pressure control device.

(Means for Solving the Problems) FIG. 1 is an overall configuration diagram for clearly showing the configuration of the present invention. Reference numeral 1 denotes a load equivalent amount detection means for detecting a load equivalent amount of the engine 13, which detects, for example, the amount of intake air. Reference numeral 2 denotes a supercharging pressure detection means, which detects the actual supercharging pressure pressurized by the compressor. Reference numeral 9 denotes a deviation calculation means that calculates the deviation between the detected boost pressure value and the target boost pressure.

Reference numeral 10 denotes a feedback region determination means, which determines whether the load equivalent amount detected value is on the lower load side than the determination value within a preset feedback region (if the load equivalent amount is the intake air amount, the determined flow rate within the feedback region). It is determined whether it is in the high load side feedback area or in the high load side feedback area.

Reference numerals 3 and 4 denote first and second control amount calculation means, respectively, and when the load equivalent amount detection value is in the low load side feedback region based on the judgment result of the feedback region inside judgment means 10, the first control amount calculation means 3
is to control the exhaust turbine capacity variable means 7 by correcting the first basic control value (for example, the basic control duty for the duty control solenoid valve) according to the load equivalent detection value based on at least the integrated value of the deviation. Similarly, when the detected value of the load equivalent amount is in the feedback region on the high load side based on the determination result of the feedback region inside determination means 10, the second control amount calculation means 4 determines the load equivalent amount based on at least the integrated value of the deviation. The control amount of the exhaust bypass valve 8 is calculated by correcting the second basic control value according to the equivalent amount detection value.

Reference numeral 5 denotes a selective control means, which controls a control amount ( The control of the capacity variable means 7 is controlled according to the first control amount), and the control amount calculated by the second control amount calculation means 4 when the detected load equivalent value is in the feedback region on the high load side. The exhaust bypass valve 8 is selectively controlled according to the control amount (control amount 2).

In this way, feedback control of the supercharging pressure is selectively performed using the variable capacity means 7 in the low-load feedback region and by using the exhaust bypass valve in the high-load feedback region.

The present invention further includes rapid acceleration determining means 11 for determining whether or not rapid acceleration is occurring when the load equivalent detected value is in the low load side feedback region based on the determination result of the feedback region determining means 10;
Based on this judgment result, the target supercharging pressure increasing means 12 increases the target supercharging pressure for a predetermined period of time during sudden acceleration, and from the judgment result of the sudden acceleration judgment means 11, the judgment value within the feedback region is set to a high load during sudden acceleration. A feedback area judgment value changing means 14 for changing the judgment value on the side is provided.

(Function) Rapid acceleration determination means 11 and target supercharging pressure increase means 1
When the load equivalent amount is in the feedback region on the low load side (that is, on the variable capacity means side), the overboost control means consisting of When boost pressure is increased, before the actual boost pressure catches up with the increased target boost pressure,
The load equivalent amount may reach the judgment value in the feedback region, and in this case, the feedback control switches to the high load side (that is, the exhaust bypass valve side), and the high target supercharging pressure during overboost control is can't get it.

In contrast, in the present invention, during sudden acceleration in the boost pressure feedback region using the capacity variable means, the feedback region judgment value changing means 14
When the judgment value in the feedback area is changed to the high load side, the feedback control may switch to the exhaust bypass valve side before the actual boost pressure catches up with the target boost pressure during overboost control. do not have. In other words, after the actual boost pressure catches up with the boost pressure during overboost control, the amount of increase (change) in the judgment value within the feedback area is increased so that the load equivalent amount reaches the judgment value within the feedback area. This means that it is set.

As a result, the target supercharging pressure during overboost control can be reliably obtained without reducing turbocharge efficiency even during sudden acceleration during supercharging pressure feedback control using the capacity variable means, and acceleration Performance can be improved.

(Embodiment) FIG. 2 is a schematic diagram of a mechanical configuration of an embodiment of the present invention. In the figure, air is supplied to an engine 21 through an intake pipe 22 and an intake manifold 23 and is exhausted through an exhaust manifold 24 and an exhaust pipe 25. An air flow meter 31 for measuring the amount of intake air Q _a is provided at the bent end of the intake pipe 22 on the left side in the figure.
A compressor 35, which constitutes a part of the turbocharger, is disposed at the bent portion 2, and pressurizes the intake air supplied through the air flow meter 31 and supplies it to the engine 21. Intake manifold 23
A throttle valve 32 is provided at the proximal end of the intake pipe 22 near the
A relief valve 29 is provided in the intake pipe 22 between the throttle valve 32 and the compressor 35.

A portion of the exhaust pipe 25 bent to the right in the figure forms a turbine chamber 38, and a turbine 37 is disposed within the turbine chamber 38. The turbine 37 is connected to the compressor 35 via a connecting shaft 36. ing. The turbine chamber 38 has a scroll 39 formed to surround the turbine 37, as shown in FIG. Therefore, it is formed gradually smaller. The introduction passage 40 to this scroll 39 and the scroll 39
A movable tongue portion 45 as a capacity variable means constituted by a flap valve is provided at the confluence portion of the terminal end portion 41 of the introduction passage 40. The base end portion is rotatably supported by a shaft 46.

This movable tongue portion 45 is connected to the exhaust pipe 2 near the upstream side, which is the introduction passage 40 to the turbine 37 in FIG.
It is located within 5. A shaft 46 rotatably supporting the movable tongue portion 45 is connected to the upper end of a rod 48 via an arm 47, and the lower end of the rod 48 is connected to a diaphragm 52 constituting an actuator 50 for driving the movable tongue portion. connected. The case 51 housing the diaphragm 52 is divided into an atmospheric chamber 53 and a positive pressure chamber 54 by the diaphragm 52, and the atmospheric chamber 53 has a spring biased to push the diaphragm 52 toward the positive pressure chamber 54. 55 are arranged. The positive pressure chamber 54 is connected to the intake pipe 22 on the downstream side of the compressor 53 via a connecting pipe 56, and the supercharging pressure generated by the compressor 35 is supplied to the positive pressure chamber 54, and the diaphragm 52 is moved by the spring 55.
It is pushed toward the atmospheric chamber 53 against the pressure. Further, a solenoid valve 57 is provided in the middle of the connecting pipe 56, and when this solenoid valve 57 is driven and released by the control unit 80, the connecting pipe 56 is communicated with the compressor inlet via this solenoid valve 57. The pressure within the positive pressure chamber 54 decreases. More specifically, the solenoid valve 57 is duty-controlled by the control unit 80, and as the duty value increases, the degree of opening of the solenoid valve 37 increases and the pressure in the positive pressure chamber 54 resists. Therefore, due to the action of the spring 55 in the atmospheric chamber 53, the diaphragm 52
moves downward, and this movement is transmitted to the movable tongue portion 45 via the rod 48, arm 47, and shaft 46, and the movable tongue portion 45 moves in the direction of reducing the exhaust gas introduction passage 40 to the turbine 37, that is, Rotate in the closing direction. As a result, the flow rate supplied to the turbine 37 increases, and the boost pressure applied to the engine 21 by the compressor 35 increases. Also, conversely,
As the duty value decreases, the degree of opening of the solenoid valve 57 decreases and the pressure in the positive pressure chamber 54 increases, so the diaphragm 52 moves upward against the spring 55, and the movable tongue 45 It rotates in the direction to open the passage 40. As a result, the flow rate supplied to the turbine 37 becomes slower, and the boost pressure applied to the engine 21 by the compressor 35 decreases.

An exhaust bypass valve (wastegate valve) 60 is provided at a connection portion between the exhaust bypass passage 26 that bypasses the turbine 37 and the exhaust manifold 24 . This exhaust bypass valve 60 is connected to one end of a rod 63 via an arm 61 and a connecting member 62, and the other end of the rod 63 is connected to a diaphragm 72 of an actuator 70 for driving the exhaust bypass valve. A case 71 housing the diaphragm 72 is divided into an atmospheric chamber 73 and a positive pressure chamber 74 by the diaphragm 72, and the atmospheric chamber 73 has a spring biased to push the diaphragm 72 toward the positive pressure chamber 74. 75 are provided. The positive pressure chamber 74 is connected to the compressor 35 via a connecting pipe 76.
The compressor 35 is connected to the intake pipe 22 on the downstream side, and supercharging pressure generated by the compressor 35 is supplied to the positive pressure chamber 74.

Further, in the middle of the connecting pipe 76, a solenoid valve 77 is provided.
When the solenoid valve 77 is driven and opened by the control unit 80, the connecting pipe 76 is communicated with the compressor inlet via the solenoid valve 77, and the pressure in the positive pressure chamber 74 is reduced.
More specifically, the solenoid valve 77 is duty-controlled by the control unit 80, and as the duty value increases, the degree of opening of the solenoid valve 77 increases, and the pressure in the positive pressure chamber 74 decreases. The diaphragm 72 moves downward under the action of the spring 75, and this movement is transmitted to the exhaust bypass valve 60 via the rod 63, the connecting member 62, and the arm 61, and the valve 60 moves in a direction to close the bypass passage 26. Furthermore, as the duty value decreases, the degree of release of the solenoid valve 77 decreases and the pressure in the positive pressure chamber 74 increases, so the diaphragm 72 moves upward against the spring 75, thereby causing the exhaust bypass valve 60 moves in the opening direction. The exhaust bypass valve 60 is provided in order to prevent damage to the engine 21 due to excessively high supercharging pressure of intake air supplied to the engine 21 by the turbocharger when the engine 21 is in a high-speed, high-load state. , part of the exhaust gas from the engine 21 is discharged to the outside to reduce the amount of exhaust gas supplied to the turbine 37 so that an appropriate boost pressure can be introduced into the engine 21.

The control unit 80 is composed of a microcomputer consisting of a microprocessor, memory, and an input/output interface including an A/D converter, and the amount of intake air is supplied to the control unit 80 from the air flow meter 31 via the interface. At the same time, the rotational speed of the engine 21 is supplied from a crank angle sensor 30 provided on the left side of the engine 21, and the supercharging pressure is supplied from a supercharging pressure sensor 33. Control unit 8
0 appropriately controls the duty value of the signal that drives the electromagnetic valves 57 and 77 according to this information, and makes the cross-sectional area of the exhaust gas introduction passage 40 to the turbine 37 via the movable tongue portion 45 variable. In addition, by making the amount of exhaust gas flowing to the turbine 37 variable through the exhaust bypass valve 60, the supercharging pressure of the intake air supplied to the engine 21 is appropriately controlled according to the amount of intake air _Qa , and low-speed operation is possible. The torque is increased from the high speed range to the high speed driving range.

Next, FIGS. 4A to 8 show flowcharts in which control of the variable capacity means (movable tongue) and the waste gate valve (exhaust bypass valve) is realized using a microcomputer. In addition, the numbers in the diagram represent processing numbers, the variable capacity means is described by the symbol VN, the waste gate valve is described by the symbol WG,
It is assumed that signals representing operating conditions such as engine rotational speed and intake air flow rate are stored in memory.

To explain from Fig. 4A, boost pressure control
VNWGCONTROL calculation processing is performed every predetermined cycle (control cycle), and the control target value (target boost pressure) of boost pressure obtained from various operating conditions P2ADAPT
The control amount for controlling VN and WG is calculated in order to make the actual boost pressure P2 match the actual supercharging pressure P2. To explain step by step, first, in 200, the air flow rate index QS is calculated from the input intake air amount QA. In addition,
In actual control, this QS is used as calculation data, but in the following explanation, for convenience, QS will be explained as an intake air amount. In 201, WG is higher than the QS value.
Find the basic control duty of BASEDUTY1. In 202, control duty is set to BASEDUTY1.
Add 35 percent. This is a correction amount to prevent the WG from opening due to missetting on the WG side or component variations. For example, in the VN side control area, if the WG opens due to a setting error or component variation on the WG side, the VN will try to increase the boost pressure and shift to the closed side, making it impossible for the VN side to perform normal learning. It becomes possible. Therefore, the control amount on the WG side is increased in advance to ensure the reliability of learning control on the VN side. In 203, in order to eliminate steady-state deviation from the control target value, the learning amount LEARNWG determined by learning control is added to BASEDUTY1. 204 checks whether overboost control is being performed, which temporarily increases boost pressure during sudden acceleration to improve acceleration performance. If it is determined that overboost control is in progress, the process advances to 205 and overboost control is performed. Add the acceleration correction amount for BASEDUTY1. Here, what is LEARNWG and acceleration correction amount?
Gives the feed forward control amount on the WG side. In addition, LEARNWG is the learning result up to the previous time,
This makes it possible to eliminate control deviations due to component variations and changes over time, and this calculation and overboost control will be described later.

On the other hand, in steps 206 to 210, the feedforward control amount on the VN side is obtained from BASEDUTY0. 201～
The difference between processing 205 and 206-210 is
The basic control duty required for BASEDUTY0
The only difference is that 5% is subtracted in 207.
This is the basic control duty table for VN.
This is the amount of correction to prevent the WG from opening when the VN deviates to the closed side due to a setting shift on the VN side or component variations.
At 208, the learning amount LEARNVN is added in the same way as on the WG side. Note that the calculation of this LEARNVN will also be described later. Here, since the basic control duty of VN and WG is given as the characteristics shown in FIG. 9A and FIG. 9B, for example, the basic control duty is obtained from the table shown in FIG.
It can be stored in ROM and found by one-dimensional lookup. However, FIG. 9C is for VN, and H represents hexadecimal representation.

For 211, actual boost pressure P2 and target boost pressure
Calculate the feedback correction amount for the deviation from P2ADAPT, and add it to the feedback control amount obtained earlier to obtain the final control signal amount.
Find BASEDUTY0 and BASEDUTY1 respectively. The feedback control P2FBCONT performed in step 211 will be described later.

212 performs overshoot prevention at the initial stage of rapid acceleration and fail-safe processing in the event of component failure. To explain the process for preventing overshoot, the boost pressure rises rapidly during sudden acceleration, but in the case of a turbocharger with VN, the boost pressure rises faster than with a normal turbocharger, so as shown in Fig. 15. This will cause an overshoot. In particular, in the example shown in the figure, the supercharging pressure exceeds 500 mmHg during overboost control, which may impair the durability of the engine. In order to prevent this, the control duty (control signal) on the WG side is temporarily reduced at the beginning of rapid acceleration to increase the flow rate of exhaust gas that bypasses the turbine 37 and is released, thereby lowering the supercharging pressure. More specifically, control duty correction on the WG side is performed using supercharging pressure as shown in FIG. That is, when the boost pressure increases due to sudden acceleration, the control duty on the WG side is reduced by 50% when the predetermined boost pressure P0 is exceeded. However, if the level of P0 is set low (for example, 375 mmHg) to prevent overshoot, the boost pressure will decrease thereafter, so the reduction due to the slice level of P0 will only occur for 0.3 seconds after the boost pressure reaches P0. After 0.3 seconds have elapsed, normal fail-safe processing is performed to gradually reduce the control duty on the WG side using P1 to P3 (>P0) as slice levels. Also, in consideration of the case where the WG does not open, if the situation continues to exceed P4, a fuel cut request flag is set to perform fuel cut by the engine control system. The control duty on the WG and VN side finally determined in this way is ONDUTY1, which will be described later.
After being transferred to ONDUTY0, they are each output to the aforementioned solenoid valves 77 and 57 via the output interface. Note that overshoot countermeasures and fail-safe measures are taken by correcting ONDUTY1 and ONDUTY0.

Next, feedback control is performed in 211.
The processing of P2FBCONT will be explained using the flowchart shown in FIG. Here, we determine the operating region in which feedback control is to be performed, determine the operating region on which side of VN or WG to perform feedback control, calculate the feedback correction amount, and calculate the learning amount, and set the final control amount to ONDUTY0, Store in ONDUTY1.

To explain step by step, at 100, processing is performed to reduce the control target value P2ADAPT in order to avoid abnormal combustion when the intake air flow rate increases. For example, a one-dimensional table as shown in Fig. 10A is stored in the memory ROM, and the intake air flow rate QS is
When the intake air flow rate QSPDOWN exceeds the predetermined intake air flow rate QSPDOWN0, the control target value is gradually decreased. VN, WG in 101
A flag indicating which control region the side is in.
Check FP2FBVNWG and if it is “1”
It is determined that feedback control is being performed on the WG side, and the process proceeds to step 111. If it is "0", the process proceeds to step 102 and thereafter, where the operating range in which feedback control is to be performed is determined and the amount of learning is calculated.

First, in 102, the actual boost pressure P2 is the area judgment boost pressure that determines the operating area where feedback control is performed.
Checks whether it is smaller than P2JUDGE (230mmHg), and if it is smaller, does not judge the operating range.
Proceed to 111. This is to prevent the feedback control from switching to the WG side before entering the overboost control after a sudden acceleration determination, which will be described later, is performed. In other words, in overboost control, sudden acceleration is determined by comparing the acceleration time from 100 mmHg to 200 mmHg with the determination standard TJUDGE, and if the acceleration time is smaller than TJUDGE, it is determined that there is sudden acceleration. However, the boost pressure
If the above driving range is to be determined even when P2 is smaller than P2JUDGE, apart from the sudden acceleration determination,
In order to determine which side of VN or WG should perform feedback control, the intake air amount QS and the feedback control area judgment air flow rate, which will be described later, are used.
A comparison with QSVNTWG will be made.
Therefore, when sudden acceleration is determined and overboost control is performed to improve responsiveness during sudden acceleration, if the intake air flow rate becomes larger than QSVNTWG.
Since it is determined that the control area is on the WG side, feedback control is applied to VN regardless of the sudden acceleration determination.
If this happens, the overboost control will be switched from the side to the WG side, making it impossible to perform overboost control.To prevent this, boost pressure P2 should be
If it is smaller than P2JUDGE, the above judgment is not performed.

In step 103, the feedback control area determination air flow rate QSVNTWG during normal operation is stored in the register ACC. This area determination air flow rate QSVNTWG is the air amount line A shown in FIG. That is, in the figure, the area to the left of line A is the control area for the VN side, and the area to the right is the control area for the WG side. 104 checks if there is sudden acceleration and flags
If FACCEL is "1", it is determined that there is a sudden acceleration and the process proceeds to 105; if it is not determined that there is a sudden acceleration, the process proceeds to 107. This flag FACCEL is a sudden acceleration determination flag that is set to "1" when sudden acceleration is determined, and will be explained in the acceleration determination process described later.
At 105, it is checked whether the overboost control has ended. If it is determined that the overboost control is in progress, the process proceeds to 106, and if it is determined that the overboost control has ended, the process proceeds to 107. In 106, the area judgment air flow rate QSVNTWGX (>QSVNTWG) during overboost control is ACC
Store in. This area judgment air flow rate
QSVNTWGX is air amount line B shown in Figure 14.
It is. That is, since the control region on the VN side expands during overboost control, the region determination air flow rate is increased from line A to line B accordingly.

In step 107, the area determination air flow rate stored in the ACC is compared with the actual intake air flow rate QS. QS is ACC
If it is larger, it is determined that it is not the control area on the VN side, and the flag FP2FBVNWG is set to "1" in step 108. As a result, FP2FBVNWG = 1 until now
This means that the control area on the VN side has been switched to the control area on the WG side, and at 109, a timer is started to start learning control on the WG side.
At step 110, the learning amount calculation ACCLEARNVN on the VN side is performed. This learning amount calculation will be described later. At 111, the flag FP2FVBNWG is checked, and if it is "0", the process goes to 113; if it is "1", the learning amount calculation ACCLEARNWG on the WG side is performed at 112. This learning amount calculation will also be described later. In this way the 14th
As shown in the figure, the operating range for feedback control is determined and the amount of learning on the VN and WG sides is calculated.

Next, from 113 onwards, the feedback correction amounts are calculated for each of the VN and WG sides. Here, we will discuss proportional-integral-derivative control, and the proportional, integral, and differential components calculated from the deviation are P, respectively.
It will be abbreviated as I minute and D minute. First, in 113, the P portion on the VN side is calculated and added to BASEDUTY0 obtained earlier, and the added result is stored in the memory M2. This P component is calculated by the following calculation, taking into consideration the stability of the control and the case where the basic control duty BASEDUTY0 is deviated. In other words, the P portion on the VN side is KPVN×
(ERROR) Set to ² . Here, ERROR is the deviation between the target boost pressure and the actual boost pressure (ERROR=P2ADAPT
−P2), and KPVN is the operational gain.
In step 114, P on the WG side is similarly calculated and added to BASEDUTY1, and the result of the addition is stored in memory M2+2. However, the P portion on the WG side is
KPWG×ERROR, where KPWG is the operational gain. In FIG. 13, the P valve on the VN side is shown by a broken line, and the P valve on the WG side is shown by a solid line.

The P component of the feedback control obtained in this way is always added, but since the integral-differential control is performed at a predetermined boost pressure or higher, it is determined in steps 115 to 118 whether or not the integral-differential control is to be performed. First, store the actual boost pressure P2 in the register ACC at 115, and then
Now check whether the target boost pressure P2ADAPT is 375mmHg. P2ADAPT is 375
If mmHg then go to 118 but P2ADAPT is
If smaller than 375mmHg, use 117
Add P2DOWNVALUE to ACC. this is,
Normally, when the boost pressure reaches P2MIN (320mmHg), it is determined that integral-derivative control is possible at the next step 118, but if the air flow rate becomes high at 100 and the control target value is lowered, the This is to make it possible to determine that control is possible from a low boost pressure. In other words, in the low and medium air flow range where the control target value is 375 mmHg, the actual boost pressure and the judged boost pressure P2MIN
(320mmHg) to determine the control region for integral-derivative control, but in the high air flow region where the control target value is lower than 375mmHg, the determination boost pressure
It is preferable that P2MIN is also made small to secure a control region for performing integral-differential control. For this register
All you need to do is to compare P2 stored in ACC with a value obtained by subtracting a predetermined value from P2MIN, but this can be done by adding the above predetermined value to P2 in advance, and comparing this added value with P2MIN. You will get the same result if you compare. The predetermined value in this case is the P2DOWNVALUE,
P2DOWNVALUE may be a constant value or may be a value that changes depending on QS.

At step 118, it is checked whether ACC is equal to or greater than P2MIN, and if it is equal to or greater than P2MIN, it is determined that control is possible and the process proceeds to step 127. If it is not determined that control is possible, QS returns the specified air flow rate at 119.
Check whether it is less than QSWGAREA, and if it is smaller, reset the various control sequence flags and initialize various feedback variables at 120, and at the same time rewrite the learning amount on both the VN and WG sides at 121. . In other words, the timing for updating the learning amount is when the boost pressure is smaller than P2MIN and the intake air amount is smaller than QSWGAREA. If it is larger, the process proceeds to step 122 in order to prevent the flag from being reset or the variables from being initialized if the supercharging pressure drops instantaneously on the high air flow rate side. In other words, when the accelerator pedal is released during full-throttle acceleration in the high air flow range, the boost pressure may drop faster than the intake air volume, and in such cases, the air flow is maintained high and the WG This results in the supercharging pressure being lower than P2MIN even though it is within the side control region. Therefore,
In this case as well, we decided to reset the above flags and initialize the feedback variables.
The cumulative deviation value ERRORIWG from the previous time on the WG side will disappear, and the control amount on the WG side will become small. If there are variations in parts, etc., this will lead to control deviations. To prevent this, reset the above flag. This is to prevent this from happening.

At 122, the values stored in memories M2 and M2+2 (results of adding various correction amounts to the basic control duty) are transferred to ONDUTY0 and ONDUTY1. Note that for this transfer, an upper limit value and a lower limit value are set, and each value on the VN and WG side is limited between the upper limit value and the lower limit value. For 123, QS is the determined air flow rate
Check whether it is smaller than QSDUTYCUT, and if it is smaller, set the control duty at 124.
Set ONDUTY0 and ONDUTY1 to the minimum value. This process is performed to increase durability by not moving the control solenoid valves 57, 77 on the low air flow rate side such as when idling. At 125, error prevention processing for acceleration determination is performed.
The contents of this process will be explained in the acceleration determination process described later. After this, VNWGCONTROL
Proceed to 212.

Next, a case where it is determined in step 118 that the integral-derivative control is in the controllable region and the process proceeds to step 127 will be described.
After 127, calculations are performed on each of the VN and WG sides based on the determination result (performed in steps 101 to 106) to determine which control region the VN or WG side is in. First, check whether the flag FP2FBVNWG is "1" at 127, and if it is "1", check at 128 the integrated value of the deviation ERROR on the WG side up to the previous time.
Add the current deviation ERROR to ERRORIWG.
If it is “0”, proceed to 129 and the deviation up to the previous time on the VN side
This deviation in the integrated value ERRORIVN of ERROR
Add ERROR. At 130, it is checked whether overboost control has started, and if it is determined that it has started, at 131, the correction amount VNCOEFI during overboost control is added to ERRORIVN. This is to add the feedforward control amount corresponding to the increase in the control target value during overboost control. If overboost control does not start
Proceed to 132 and check FP2FBVNWG. If it is "1", it is the control area on the WG side, so proceed to 133 and check VN.
The specified amount is subtracted from the integrated value ERRORIVN of the side deviation ERROR. As a result, after the feedback control is switched from the VN side to the WG side, the control amount on the VN side is gradually reduced from the control amount immediately before the switch. That is, if the control amount on the VN side is maintained at the control amount immediately before switching even after the feedback control is switched to the WG side, as the exhaust gas flow rate increases, the flow velocity in the introduction passage 40 increases and the pressure decreases. This pressure drop causes the movable tongue portion 45 to rotate in a direction to close the introduction passage 40, thereby reducing the capacity of the turbocharger. In contrast,
When a predetermined value is subtracted from the integrated value ERRORIVN of the deviation ERROR on the VN side, the movable tongue portion 45 moves toward the introduction passage 40.
Since it is rotated in the opening direction and becomes fully open, sufficient exhaust flow can be ensured even when the WG side controls it, and the performance of the turbocharger can be maximized. On the other hand, if FP2FBVNWG is “0”, proceed to 134 and calculate the I portion on the VN side by KIVN ×
Calculate ERRORIVN and add this to M2 above. Here, KIVN is the operational integral gain. At the same time, this I portion is stored in VNLEARN as the current learning amount on the VN side for learning control. In 135, the I portion on the WG side is KIWG ×
Obtain it by calculating ERRORIWG and use it as M2
Add to +2. Here, KIWG is the computational integral gain. At the same time, this I
The minutes are stored in WGLEARN as the amount of learning on the WG side this time. At step 136, D is calculated and the result is stored in memory M1. The calculation for this D is KD×
Calculate by (ERROR1−ERROR). Here
KD is the operational differential gain. in particular,
Check whether VN or WG is controlling
FP2FBVNWG is checked, and if it is in the VN side control area, the VN side gain KDVN is selected, and if it is in the WG side control area, the WG side gain KDWG is selected and calculated. Note that ERROR1 is a full-throttle ERROR. In 137, when FP2FBVNWG is “1”, it is 138
Add D on the WG side to the WG side, store the added result in M2+2, and when it is “0”, add it in 139.
Add the D portion on the VN side to the VN side, and the result of the addition is
Store in M2. In 140, this error occurs due to the calculation of D in the next calculation process.
Store ERROR (=P2ADAPT-P2) in ERROR1. At 141 and 142, the values stored in the memories M2 and M2+2 (results of adding various correction amounts to the basic control duty) are transferred to ONDUTY0 and ONDUTY1 as the final control duty. Please note that upper and lower limits are set for this transfer.
Each value on the VN and WG sides is limited between the upper and lower limits. After this, VNWGCONTROL
Proceed to 212.

Next, overboost control, which temporarily increases boost pressure during sudden acceleration to improve acceleration performance, will be described. This control corresponds to the main part of the present invention, and basically corrects the above-mentioned feedforward control amount and increases the control target value to realize overboost control. Fourth
Figure B is a flowchart of the process BOOSTCNTR that sets and resets various flags for overboost control, and Figure 6A is the sudden acceleration determination process ACCELJUDGE.
The flowchart is shown below.

First, the determination of sudden acceleration will be explained step by step based on FIG. 6A. This process is executed once every 10ms, in addition to the control calculation process described earlier. At 300, boost pressure is stored in P2. In 301
It is checked whether P2 has exceeded 100 mmHg, and if it has not, in 302, various control sequence flags are reset and various variables are initialized.
If it is 100mmHg or more, proceed to 303, and if it exceeds it for the first time, proceed to 304 and start the acceleration time measurement timer. 305 calculates the time that is the criterion based on the engine rotation speed at 100mmHg, gear position, etc., and stores this in TJUDGE. This criterion is the first
The judgment line as shown in Figure 2B, that is, the engine rotation speed (rpm) at 156250/100mmHg (
×10ms) If the acceleration time τ, which will be described later, is in the region below this determination line, it is determined that the acceleration is sudden. The numbers in the figure represent the gear positions from 1st to 4th gear of the transmission, and up to 3rd gear there is no problem as it falls within the lower limit of the judgment line, but in 4th gear, the acceleration time τ in the low rotation range
(The time it takes for the boost pressure to go from 100mmHg to 200mmHg) crosses the judgment line and is distributed in the area surrounded by the broken line in the figure. Therefore, in the 4th speed low speed rotation range, it is necessary to move the judgment line beyond this area, and the value obtained by adding a predetermined value to the value of the judgment line is used as the judgment standard. For these reasons, the transmission gear position is also taken into consideration as a criterion.

If P2 exceeds 100mmHg for the second time or later in 303, proceed to 307, check whether P2 exceeds 200mmHg, and if it is smaller than 200mmHg, do not judge sudden acceleration. If it is 200mmHg or more, the timer value started at 304, that is, the acceleration time τ shown in Fig.
Judgment criteria determined by 305 (time to reach Hg)
Check whether it is smaller than TJUDGE, and if it is smaller, proceed to 309, determine that sudden acceleration is occurring, and set FACCEL to "1". After that, the process returns to engine control. In this way, the input of the boost pressure necessary for control and the judgment of the sudden acceleration state are performed, and this information is transmitted to the VNWGCONTROL shown in Figure 4A and the VNWG CONTROL shown in Figure 5.
P2FBCONT, as shown in Figure 4B, which will be explained next.
Use with BOOSTCNTR.

Next, the process BOOSTCNTR for optimally performing overboost control will be explained using FIG. 4B. This BOOSTCNTR is executed once before executing VNWGCOVTROL, and various information necessary for overboost control is transferred. To explain step by step, first, at 214, it is checked whether overboost control has ended. This is discussed below
This is done by checking the processing results for terminating the overboost control performed in steps 236-239. If it is determined that the control has ended, the process proceeds to 241 and a process of gradually lowering the control target value (a process of gradually decreasing the feedforward control amount during overboost control) is performed. If the control has not been completed, proceed to 215 and check the sudden acceleration determination flag FACCEL, which is set or reset in the sudden acceleration determination process described above. If it is "0", the process is terminated, and if it is "1", sudden acceleration is detected. has been determined, so proceed to 216 and check whether overboost control is permitted. This is the engine,
Since whether or not overboost control is performed differs depending on the vehicle model, for example, by storing this information in the memory ROM, the same program can handle different specifications with or without overboost control. If overboost control is permitted, proceed to 217 and check whether the engine water temperature is below 100℃. Overboost control is not performed when the temperature is 100°C or higher, as abnormal combustion is likely to occur. If the temperature is less than 100°C, proceed to 218 and set the feed forward correction start flag FP2WG on the WG side to "1". At 219, it is checked whether the supercharging pressure exceeds 250 mmHg, and if it does not, the process is terminated. If it is exceeded, proceed to 221.
If it exceeds 250mmHg for the first time, proceed to 222, start the sudden acceleration judgment error prevention timer, and
Side feed forward correction start flag FP2VN
is set to “1”. The measurement time of this erroneous judgment prevention timer is checked in the sudden acceleration judgment error prevention process at 125 in Fig. 5 mentioned above, and if 3 seconds or more elapses from exceeding 250 mmHg to 320 mmHg, sudden acceleration is determined. No judgment, sudden acceleration judgment flag
Reset FACCEL and the feed forward correction start flag FP2VN on the VN side to "0". This is because, as shown in Fig. 16, when the transmission gear position is 2nd speed and the throttle valve opening is accelerating from 1/4, the time of τ used to determine sudden acceleration is short and it is determined that the acceleration is sudden. This is because the acceleration time is short and overboost control is entered after acceleration is completed to prevent sudden changes in supercharging pressure and deterioration of drivability. That is, if the time T0 measured by the misjudgment prevention timer from 250 mmHg to 320 mmHg becomes T0≧3, it is not considered to be a sudden acceleration. Next, if 221 exceeds 250mmHg for the second time or later, proceed to 223 and boost pressure P2
Check whether it exceeds 345mmHg. If it exceeds 345mmHg, proceed to 225 and check whether it exceeds 345mmHg for the first time. If it is exceeded for the first time, the process proceeds to 226, starts a timing timer that measures the timing to increase the control target value, and ends the process.
228 if the temperature exceeds 345mmHg from the second time on 225
The process advances to step 226 to check whether the timing timer activated has elapsed for a predetermined period of time (0.3 seconds), and if the timing timer has elapsed, the process proceeds to step 229. If the predetermined time has elapsed for the first time, the process proceeds to 230, where the overboost control amount according to the engine water temperature is determined and the control target value is increased. In other words, by using a one-dimensional table according to the water temperature as shown in Figure 10B, the control target value 425 mmHg during overboost control is reduced as the water temperature rises (the predetermined amount to be reduced is increased), thereby determining the optimum overboost control amount. give.

Next, when proceeding from 228 and 229 to 232 and onwards, from 232 onwards, the overboost control termination condition is checked. In other words, in 232 and 234, the boost pressure is
In order to measure the elapsed time from the time when 375 mmHg was exceeded, when 375 mmHg is exceeded for the first time at 234, the process proceeds to 235 and a timer for measuring overboost control time is activated. If the temperature exceeds 375 mmHg for the second time or later at 234, the process advances to 236 and checks whether the control time measurement timer started at 235 has exceeded a predetermined time. If it exceeds the limit, proceed to 239 and end the overboost control. If the knocking level is not exceeded, proceed to 237 and check the knocking level, and if it is greater, the overboost control is terminated to prevent knocking. If it is small, proceed to 238 and determine the air amount QSBOOSTCUT to determine when QS cuts overboost control.
Check whether it is larger than that, and if it is larger, proceed to 239 and end the overboost control to prevent abnormal combustion. in this way
The BOOSTCNTR process processes various information for overboost control.

Next, we will explain learning control that corrects deviations in feedforward control amounts on the VN and WG sides. First, on the VN side, the timing to calculate the amount of learning is 110 in Figure 5, and from the VN side
This is the time to switch to feedback control on the working group side. The amount of learning is assumed to be I stored in VNLEARN at 134 in the same figure. This means that the steady-state deviation when the boost pressure is controlled on the VN side is added to the feedforward control amount in advance from the next control. The actual learning amount calculation will be explained based on FIG. 7. First, at 400, it is checked by FACCEL whether overboost control is being performed. The learning amount calculation is of course possible even when overboost control is not performed, but when overboost control is performed, the value of I is large because the control region on the VN side is expanded in that control region. Since the control accuracy can be improved by performing control using this large value, in this embodiment, the learning amount calculation is performed immediately after performing the overboost control. That is, the learning amount is not calculated in acceleration situations where overboost control is not performed.
If overboost control is performed, proceed to 401 and find the steady state deviation VNLEARN at 134 in Figure 5.
Subtract the correction amount for overboost control (15% of the control duty) from , and use the subtracted result as VNLEARN. This is because the basic control duty is optimally applied when not in overboost control. For 402, add this VNLEARN and LEARNVN.
Store in VNLEARNVALUE. Here
LEARNVN is the previous learning result, and this value
This is to ensure that the learning amount converges to the optimal value by adding LEARNVN and the current learning result VNLEARN. The latest learning results memorized in this way
VNLEARNVALUE is 121 in Figure 5, that is, the boost pressure is smaller than 320mmHg and QS is
By updating when the feedback control reset condition, which becomes smaller than QSWGAREA, is satisfied, it will be reflected in the next control. In this example, the update timing is set to be when two conditions are satisfied, but it may be at least as long as the condition that the pressure is lower than the predetermined boost pressure is satisfied.

Next, learning control on the WG side will be explained. The timing for calculating the learning amount is 11 in Figure 5.
2, after 1.2 seconds have passed since the feedforward control was switched to the WG side. The amount of learning is 135
Let it be the I minute stored in WGLEARN. This means that the steady-state deviation when the boost pressure is controlled on the WG side is added to the feedforward control amount in advance from the next control. The actual learning amount calculation will be explained based on FIG. 8. First, in 404, the measured value of the learning control start timer WGLEARNTIMER on the WG side, which was started at 109 in FIG. 5, that is, when the feedback control was switched to the WG side. Check whether the time is 1.2 seconds or more.
If the time is less than 1.2 seconds, no learning amount calculation is performed.
If more than 1.2 seconds have elapsed, proceed to 405 and calculate the current steady deviation obtained at 135 in Figure 5 in the same way as on the VN side.
Add WGLEARN and the previous learning amount LEARNWG and store it in WGLEARNVALUE. This latest learned value is updated at the same timing as on the VN side, that is, at 121 in FIG. In this way, VN, WG
The learning amount is calculated and updated at the optimal timing for each side, and this updated value is
Above mentioned as LEARNVN, LEARNWG
VNWGCONTROL 203 and 208 (FIG. 4A) add, that is, correct the feedforward control amount.

Further, the various time measurement timers used in the above explanation are realized by a configuration in which the timers are incremented by 1 at fixed time intervals (10 ms) by TIMER processing, as shown in FIG. 6B.

Next, before explaining the operation and effect of this embodiment, the relationship between the control duty on the VN side and the air flow rate will be explained first. It is a characteristic diagram shown for comparison. As shown in the figure, during overboost control, VN
Area judgment air flow rate for switching control from side to WG side is from A (QSVNTWG) to B (QSVNTWGX)
This has expanded the control area on the VN side. Note that the difference between the curves in the vertical axis direction represents the acceleration correction amount described above.

FIG. 18A is a diagram showing the operation and effect when full acceleration is performed from actual 4th gear 40 km/h using such control duty. In the figure, the horizontal axis shows the elapsed time after the throttle valve fully opens, and the vertical axis shows the boost pressure (compressor outlet pressure), control duty on the VN side (basic control duty and actual control duty), VN opening, The air flow index and WG opening are shown respectively. The basic control duty is shown in Figure 4A.
The table is pulled up at 206 of
This corresponds to the value of BASEDUTY0, and the actual control duty corresponds to the value stored in ONDUTY0 in FIG.

When the accelerator pedal is depressed at the T0 point and acceleration starts, the boost pressure increases, and until the T1 point, that is, the boost pressure reaches 320 mmHg, both VN and WG sides are QS.
Control is performed using an actual control duty obtained by adding P to the basic control duty corresponding to the actual control duty. In this region, the P component is a relatively large positive value, and the basic control duty is also a large value, so the sum becomes an upper limit of nearly 100%, and the VN opening is reduced (WG opening is fully closed). Control is performed to raise the boost pressure to the control target value as much as possible. After passing the T1 point, it becomes a control area where feedback control is performed on the VN side, so I and D
VN at the actual control duty (total of the basic control duty, P minute, I minute, and D minute) with additional minutes added.
is controlled, but on the other hand, when overboost control is performed as a result of sudden acceleration determination, the area judgment air flow rate for switching control from the VN side to the WG side is QSVNTWG.
(QS value 02EH) to large value QSVNTWGX
(QS value is 048H) and the control area on the VN side expands. Therefore, during overboost control, the VN
is controlled at a value according to the deviation from the actual boost pressure. That is, the value of the actual control duty on the VN side is large, and due to this large value, the VN opening degree is kept small and the target supercharging pressure (425 mmHg) during overboost control can be reached. As a result, during overboost control, the engine output is increased by a higher target supercharging pressure than during normal operation, thereby improving acceleration performance.
Note that the target boost pressure is increased at the T2 point where the actual boost pressure becomes 375 mmHg.

Next, at the T4 point where the overboost control ends, the normal operating state is switched to, so the area determination air flow rate changes from QSVNTWGX to QSVNTWG again. In this state, the actual air flow rate is QSVNTWG
Since it exceeds the range, the control area is immediately switched to the one where feedback control is performed on the WG side, and the feedback control on the VN side is removed. In other words, the actual control duty on the VN side after switching is a value in which only P is added to the basic control duty, but in this state, the supercharging pressure is almost the target supercharging pressure, so there is almost no deviation. (the P portion is small), and the actual control duty approaches the value of the basic control duty. Therefore, as the actual control duty value decreases, the VN opening degree gradually increases, increasing the turbine capacity. After that, when the VN opening is fully opened, the boost pressure is controlled to the control target value by the WG opening.

Furthermore, Fig. 18B shows the action and effect when full acceleration is performed from 80 km/h in 4th gear, but it is possible to obtain the same action and effect as Fig. 18A by expanding the control range on the VN side. is made of.

Next, for comparison with this example, the results of experiments conducted using other methods under the same operating conditions are shown in the first example.
This is shown in FIG. 9A, FIG. 19B, FIG. 20A, and FIG. 20B. Note that Figure 19A and Figure 20A are Figure 18A.
19B and 20B correspond to FIG. 18B.
corresponds to Explaining from FIGS. 19A and 19B, this is because the value of QSVNTWG is simply set to a value larger than that of the previous embodiment (the value of QS is
034H). In this example, during sudden acceleration from a low load (full throttle acceleration from 4th gear 40km/h), the target boost pressure during overboost control cannot be reached because it is in the VN side control region even during overboost control. However, during rapid acceleration from a high load (full throttle acceleration from 4th gear 80 km/h), the air flow rate is originally large, so the control area is switched to the WG side at the beginning of acceleration (switching with QSVNTWG). ). For this reason,
On the VN side where feedback control is removed, the control duty value rapidly becomes small, so the VN opening becomes fully open during overboost control, and the target boost pressure (425mmHg) cannot be reached.

On the other hand, Figure 20A and Figure 20B
Set QSVNTWG to the same value as in Figures 19A and 19B (QS value 034H), and at the same time, VN during overboost control during sudden acceleration from high load.
QSVNTWGADD (QS value 040H) from the moment the opening becomes QSVNTWG to prevent the opening from being fully open.
This is an example in which the actual control duty on the VN side is fixed to a constant value. In this example, the VN opening is kept small during sudden acceleration from a high load, so the A/R is small and the target boost pressure (425 mmHg) during overboost control can be reached, but the target boost pressure Boost pressure control after reaching the limit is impossible on the VN side with a fixed control duty, so the WG side has to control it instead, which causes the WG to open early. That is, if the VN opening is fixed and kept small, the efficiency of the turbocharger will decrease, the exhaust pressure will become extremely high, and the engine output will decrease.

However, this embodiment does not cause the inconveniences seen in these examples, and as mentioned above, it is possible to obtain the target supercharging pressure during overboost control without reducing the efficiency of the turbocharger during overboost control. This makes it possible to improve acceleration performance.

(Effects of the Invention) The present invention provides a result of determining whether an engine load equivalent detected value is in a feedback region on the lower load side or in a feedback region on the higher load side than a judgment value within a preset feedback region. Therefore, when the load equivalent amount detected value is in the feedback region on the low load side, at least the first basic control according to the load equivalent amount detected value is performed based on the integrated value of the deviation between the boost pressure detected value and the target boost pressure. When the load equivalent amount is in the feedback region on the high load side, the control amount of the exhaust turbine capacity variable means is corrected by correcting the control amount, and at least the second value is adjusted according to the load equivalent amount detected value based on the integrated value of the deviation. The control amount of the exhaust bypass valve is calculated by correcting the basic control value, and when the detected load equivalent value is in the low-load feedback region, the control amount is calculated according to the control amount obtained by correcting the first basic correction amount. control of the capacity variable means of the exhaust turbine, and control of the exhaust bypass valve in accordance with the control amount obtained by correcting the second basic control amount when the load equivalent amount detected value is in the feedback region on the high load side. In a boost pressure control device for a turbocharger that selectively performs the following, the target boost pressure is raised for a predetermined period of time during sudden acceleration when the load equivalent detection value is in the low load feedback region based on the judgment result. At the same time, the judgment value in the feedback area is changed to the high load side.
To improve acceleration performance by reliably obtaining target supercharging pressure during overboost control without reducing turbocharge efficiency even during sudden acceleration during supercharging pressure feedback control using a capacity variable means. I can do it.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram for clearly showing the configuration of the present invention. FIG. 2 is a schematic diagram of the mechanical structure of an embodiment of the present invention, and FIG. 3 is a sectional view of the scroll portion of the turbocharger of this embodiment. 4A, 4B, 5, 6A, 6B, 7, and 8 are flowcharts showing the operation of this embodiment. Figures 9A and 9B are VN, respectively.
A characteristic diagram showing the basic control duty of WG, and FIG. 9C is a table showing the relationship between QS and basic control duty. FIG. 10A is a characteristic diagram showing the control target value for QS, and FIG. 10B is a characteristic diagram showing the decrease in the overboost control amount with respect to engine water temperature. FIG. 11 is a characteristic diagram showing the rate of decrease in control duty with respect to boost pressure for explaining overshoot countermeasures and failsafe. Figure 12A
is a diagram for explaining τ, and FIG. 12B is a characteristic diagram for explaining the relationship between engine rotational speed and τ at 100 mmHg. Fig. 13 is a characteristic diagram explaining the relationship between error and P component (correction amount), Fig. 14 is a characteristic diagram illustrating the relationship between error and P component (correction amount), and Fig. 14 shows VN for QS,
FIG. 3 is a characteristic diagram illustrating each control area on the WG side. FIG. 15 is a supercharging pressure characteristic diagram illustrating overshoot during sudden acceleration, and FIG. 16 is a supercharging pressure characteristic diagram illustrating prevention of errors in sudden acceleration determination. FIG. 17 is a characteristic diagram showing a comparison of the control duty on the VN side according to this embodiment when overboost control is performed and when it is not overboost control. Figure 18A, 18th
Figure B is an explanatory diagram showing the action and effect of this embodiment regarding sudden acceleration from low load and sudden acceleration from high load, respectively. Figure 19A, Figure 19B, Figure 20A, Figure 20B are An explanatory diagram showing the operation and effect in an example performed under the same operating conditions as the example with a configuration different from that of the example,
Figures 19A and 20A are shown in Figure 18A and 19
Figures B and 20B correspond to Figure 18B. 1...Load equivalent amount detection means, 2...Supercharging pressure detection means, 3...First control amount calculation means, 4...Second
control amount calculation means, 5...selective control means, 7...
...Capacity variable means, 8...Exhaust bypass valve, 9...
Deviation calculating means, 10... Feedback region determining means, 11... Rapid acceleration determining means, 12... Target supercharging pressure increasing means, 13... Engine, 14...
Feedback area judgment value changing means, 21...
Engine, 22...Intake pipe, 23...Intake manifold, 24...Exhaust manifold, 25...Exhaust pipe, 26...Bypass passage, 30...Crank angle sensor, 31...Air flow meter, 32...
Throttle valve, 33... Boost pressure sensor, 35... Compressor, 36... Connection shaft, 37... Turbine, 3
8... Turbine chamber, 39... Scroll, 40...
...Introduction passage, 41...Terminal part, 45...Movable tongue part, 46...Shaft, 47...Arm, 48...Rod, 50...Actuator, 52...Diaphragm, 54...Positive pressure chamber, 56 ...Connecting pipe, 57...
... Solenoid valve, 60 ... Exhaust bypass valve, 61 ... Arm, 62 ... Connection member, 63 ... Rod, 70
... Actuator, 72 ... Diaphragm, 7
4... Positive pressure chamber, 76... Connecting pipe, 77... Solenoid valve, 80... Control unit.

Claims (1)

[Claims] 1 A load equivalent amount detection means for detecting an engine load equivalent amount, a boost pressure detection means for detecting boost pressure, and a deviation calculation means for calculating the deviation between this detected boost pressure value and a target boost pressure. , a feedback area determination means for determining whether the load equivalent detected value is in a feedback area on the lower load side or in a feedback area on the higher load side than a determination value within a preset feedback area; As a result, when the load equivalent amount detected value is in the low load side feedback region, the first basic control value corresponding to the load equivalent amount detected value is corrected based on at least the integrated value of the deviation to vary the capacity of the exhaust turbine. a first control amount calculation means for calculating a control amount of the means; and a first control amount calculation means for calculating the load equivalent amount based on at least the integrated value of the deviation when the load equivalent amount detection value is in the feedback region on the high load side according to the judgment result. a second control amount calculation means that calculates the control amount of the exhaust bypass valve by correcting the second basic control value according to the value; At certain times, the capacity variable means is controlled in accordance with the control amount calculated by the first control amount calculation means, and when the load equivalent amount detection value is in the feedback region on the high load side, the second control amount calculation means In a turbocharger supercharging pressure control device comprising a selective control means for selectively controlling an exhaust bypass valve according to a control amount calculated by rapid acceleration determination means for determining whether or not sudden acceleration is occurring when the area is within the range; target boost pressure increasing means for increasing the target boost pressure for a predetermined period of time during sudden acceleration based on the determination result; A supercharging pressure control device for a turbocharger, comprising a feedback region determination value changing means for changing the determination value within the feedback region to a high load side during sudden acceleration based on the determination result of the means.