JPH03233134A - Controller of engine with supercharger - Google Patents

Abstract

PURPOSE:To provide compatibility between improvement in a fuel consumption rate at a normal operation time and improvement in response at an operation time requiring acceleration by opening and closing an intake relief valve so as to control supercharging pressure under a temporarily closed condition of a waste gate valve until the supercharge pressure becomes the target supercharge pressure in an operation condition requiring acceleration. CONSTITUTION:Under a normal operation condition by an operation condition judgement means 81, an intake relief valve 356 is opened, a waste gate valve 27 is controlled in its opening/closing by specified control gain based on a load requirement detection means 64 so that exhaust gas required only for setting a supercharge pressure to the target supercharger pressure may by supplied to a turbine 5. On the other hand, under an operation condition requiring acceleration by the means 81, the valve 27 is temporarily closed until a supercharge pressure becomes the target supercharge pressure, and all of exhaust gas flows through the turbine 5 of an exhaust turbo supercharger 4 so as to maintain intake air in the supercharger 4 in its condition possible to be pressurized. Accordingly when intake air quantity is decreased by controlling a valve 35b to the close side by a specified control gain based on a detection means 64, a supercharge pressure increases rapidly and suppercharge time lag is reduced so as to improve responsiveness.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a control device for a supercharged engine, and more specifically, the present invention relates to a control device for a supercharged engine, and more specifically, a control device for controlling a supercharged engine during normal operation or during acceleration request operation. This relates to the control of each valve that adjusts the boost pressure on the exhaust side or the intake side so that the boost pressure is the same as the boost pressure.

(Prior Art) Generally, in an engine equipped with an exhaust turbo supercharger, a speed detection device is used as an engine rotation speed detection means for detecting the engine rotation speed, as disclosed in Japanese Patent Publication No. 62-9723, for example. , an exhaust turbo supercharger that supercharges the engine and includes a turbine driven by exhaust gas and a blower that pressurizes intake air; and an exhaust turbo supercharger that is provided in a bypass passage provided in the exhaust passage so as to bypass the turbine. a wastegate valve that adjusts the flow rate of exhaust gas to the turbine, and a target boost pressure that corresponds to the engine rotational speed and engine load request (for example, accelerator operation amount, etc.) detected by the speed detection device.
It is known that the vehicle is equipped with a supercharging pressure control means that adjusts the amount of the waste gate valve to an appropriate amount during operation requiring acceleration, such as when the load is high, to optimize the supercharging pressure characteristics.

In this case, during normal operation, the amount of exhaust gas increases as the engine speed increases, starting from a non-supercharging region where the supercharger does not substantially work, such as a low engine speed region, and the supercharger is supercharging the engine. When shifting to the supercharging range where the effect can be obtained, the wastegate valve is controlled to open and close with a predetermined control gain based on the accelerator operation acceleration so that the boost pressure becomes the target boost pressure. become.

(Problems to be Solved by the Invention) By the way, in the non-supercharged region where the supercharger does no work as described above, the supercharger only acts as resistance to intake and exhaust. Therefore, the structure is configured so that the intake air can bypass the blower, and the exhaust gas can also bypass the turbine. In the non-supercharged region where the turbocharger does not work, intake/exhaust bypass processing is performed to reduce intake/exhaust resistance. At the same time, in the supercharging region where the supercharging effect of the supercharger is required, the wastegate valve is opened and closed so that only the energy necessary for the supercharger to reach the target boost pressure is obtained from the rotation of the turbine. It is possible to reduce the

However, with this, the supercharger stops in the low engine speed range, so when the load suddenly increases, such as during acceleration request operation, the turbocharger starts up slowly, causing a time lag, and the response during acceleration request operation. The disadvantage is that it worsens.

Therefore, in order to solve the above problems, the amount of bypass intake air is reduced even in the low engine speed range, and that amount of intake air is allowed to flow through the blower, thereby pre-rotating the turbocharger and bringing the boost pressure to the target boost pressure. It is possible to keep it close. In this way, since the supercharger is pre-rotated, the supercharging time lag during acceleration request operation can be reduced.

However, although pre-rotating the supercharger in this way has the advantage of reducing the supercharging time lag, the supercharger is doing work to compensate for the pre-rotating, and non-supercharging where the supercharger is not doing the work. It is disadvantageous in terms of fuel efficiency when compared to other regions.

The present invention has been made in view of these points, and its purpose is to further improve the control device that controls the above-mentioned bypass exhaust amount and bypass intake amount, so that these controls can be adjusted according to the operating state. By being able to switch as appropriate, the fuel consumption rate can be improved during normal operation and during acceleration request operation. This is an attempt to achieve both improvement in response due to a reduction in supercharging time lag at the time of acceleration request.

(Means for solving the problem) In order to achieve the above object, the solution taken by the present invention is as follows:
As shown in FIG. 1, the control device for a supercharged engine includes an engine rotation speed detection means for detecting the engine rotation speed, a load request detection means for detecting the load request of the engine, and a supercharged engine driven by exhaust gas. an exhaust turbo supercharger for supercharging an engine, which includes a turbine for pressurizing intake air and a blower for pressurizing intake air; a waste gate valve for adjusting the flow rate of exhaust gas to the turbine of the exhaust turbo supercharger; It includes an intake relief valve that adjusts the amount of intake air that bypasses the blower. and a driving state determining means for determining a normal driving state and an acceleration request driving state based on the rain detection value detected by the engine rotation speed detecting means and the load request detecting means; Based on the state, under normal operating conditions, boost pressure is increased by opening and closing the wastegate valve with the intake relief valve open so that the target boost pressure corresponds to the detected value detected by the load request detection means. While controlling
In the acceleration request operation state, the wastegate valve is temporarily closed until the boost pressure reaches the target boost pressure so that the target boost pressure corresponds to the detected value detected by the load need/undetected means. This configuration includes supercharging pressure control means for controlling supercharging pressure by opening and closing an intake relief valve.

(Function) With the above configuration, in the present invention, the normal operating state and the acceleration request operating state are determined by the operating state determining means 81 based on the rain detection value by the engine rotation speed detecting means 61 and the load request detecting means 64, Based on this determination, in the normal operating state, the intake relief valve 35b is opened, the amount of bypass intake air is increased, and the work of the exhaust turbo supercharger 4 is reduced. In that case, the waste gate valve 27 is controlled to open and close with a predetermined control gain based on the load request detection means 64, so that only the exhaust gas necessary for the boost pressure to reach the target boost pressure is supplied to the turbine 4, and the remaining The exhaust gas is bypassed through the wastegate valve 27, resulting in a good fuel consumption rate with no waste in energy efficiency.

On the other hand, in the acceleration request operation state, the wastegate valve 27 is temporarily closed until the boost pressure reaches the target boost pressure, and the entire amount of exhaust gas discharged from the engine is transferred to the exhaust turbo supercharger 4.
The exhaust gas flows through the turbine 5 to maintain the exhaust turbocharger in a state where it can pressurize the intake air. Therefore, with a predetermined control gain based on the load request detection means 64, the intake relief valve
When the intake relief valve 35b is controlled to the closed side to reduce the amount of bypass intake air, the supercharging pressure immediately increases. On the other hand, when the intake relief valve 35b is controlled to the open side to ensure a predetermined bypass intake amount (relief amount), the supercharging pressure increases. drops immediately. That is, by keeping the turbine 5 of the exhaust turbocharger 4 in a constantly rotating pre-rotated state and controlling the opening/closing of the intake relief valve 35b to adjust the amount of intake air bypass, overload can be avoided, especially when acceleration is requested when the load increases. Due to the pre-rotation of the charger 4, the supercharging pressure is rapidly increasing from a state (approaching the target supercharging pressure) to a supercharging region where the supercharging effect is sufficiently obtained (a state where the target supercharging pressure is reached). This reduces supercharging time lag and improves response during acceleration request driving.

(Example) Hereinafter, an example of the present invention will be described based on the drawings from FIG. 2 onwards.

FIG. 2 shows a 20-type turbocharged rotary piston engine equipped with a supercharged engine control device according to an embodiment of the present invention. This supercharging system includes a primary turbo supercharger and a secondary turbo supercharger. This is a so-called sequential turbo type. In FIG. 2, 1 is an engine, and exhaust passages 2.3 for each cylinder.
are provided independently from each other. One of these two exhaust passages 2.3 is equipped with a primary turbo supercharger 4.
The turbine 5 of the secondary turbocharger 6 is disposed on the other side, and the turbine 7 of the secondary turbocharger 6 is disposed on the other side. That is, in this engine 1, the exhaust passages 2.3 of each cylinder are independently guided to the turbines 5.7 of the primary and secondary exhaust turbo superchargers 4, 6. .6 allows exhaust dynamic pressure to effectively act on both turbines 5 and 7 in the supercharging region where supercharging is performed, thereby improving supercharging efficiency. The two exhaust passages 2.3 merge downstream of both turbines 5.7 to form a single exhaust passage 2.
It is now 4.

Further, the intake passage 9a is divided into two downstream of an air cleaner (not shown), and the blower 11 of the primary turbo supercharger 4 is located in the middle of the first branch passage 10, and the blower 11 of the primary turbo supercharger 4 is located in the middle of the second branch passage 12. A blower 13 of the secondary turbocharger 6 is installed. These branch passages 10.12 are formed so as to face each other at the branch part and extend substantially straight on both sides. In addition, two branch passages 10, 1
2 join together again downstream of each blower 11, 13.

Then, an intercooler 14 is disposed in the intake passage 9b, which has become one again, and a surge tank 15 is disposed downstream of the intercooler 14, and a throttle valve 16 is disposed between the intercooler 14 and the surge tank 15. It is set up. Further, the downstream end of the intake passage 9b branches into two independent intake passages 17 and 18 corresponding to each cylinder of the engine 1, and is connected to each intake port (not shown). Each of these independent intake passages 17 and 18 has a fuel injection valve 19°2.
0 is set.

An air flow meter 21 is provided upstream of the intake passage 9a and is located upstream of the branch of the first and second branch passages 10.12 to detect the amount of intake air.

The two exhaust passages 2 and 3 are communicated with each other by a relatively small diameter communication passage 22 upstream of both the primary and secondary turbochargers 4.6. In the exhaust passage 3 in which the secondary turbine 7 is disposed, an exhaust cut valve 2 is located immediately downstream of the opening position of the communication passage 22.
3 is provided. The exhaust cut valve 23 is of a so-called normally closed type. That is,
A diaphragm type actuator 31 is linked to this exhaust cut valve 23 . A spring 31a is provided within the actuator 31 to always bias the exhaust cut valve 23 in the closing direction. Therefore,
When the engine is not operating, the actuator 31 is not operating, so the exhaust cut valve 23 is closed by the biasing force of the spring 31a.On the other hand, when the engine is operating and the actuator 31 is turned on, the actuator 31 is operated by the actuating force of the actuator 31, and the exhaust cut valve 23 is closed by the spring 31a. The exhaust cut valve 23 is rotated clockwise in FIG. 2 to open against the biasing force of the exhaust cut valve 23 and the exhaust dynamic pressure on the upstream side of the exhaust cut valve 23.

Further, a waste gate passage 25 is formed which communicates with the combined exhaust passage 24 downstream of the turbine 5.7, and a waste gate valve 27 to which a diaphragm type actuator 26 is linked is disposed in the waste gate passage 25. ing.

An exhaust leakage passage 28 is provided that communicates the wastegate valve upstream portion of the wastegate passage 25 with the exhaust cut valve downstream portion of the exhaust passage 3 connected to the secondary turbine 7. The exhaust leakage passage 28 is provided with an exhaust leakage valve 30 linked to a diaphragm type actuator 29 .

On the other hand, an intake cut valve 32 is disposed downstream of the blower 13 in the branch passage 12 in which the blower 13 of the secondary turbocharger 6 is disposed. This intake cut valve 32 is constituted by a butterfly valve, and is also linked to a diaphragm type actuator 33. Further, a relief passage 34a is formed in the branch passage 12 on the secondary side so as to bypass the blower 13.
has a diaphragm type secondary intake relief valve 35.
A is arranged. On the other hand, primary turbo supercharger 4
The branch passage 10 in which the blower 11 is disposed has the blower 1
A relief passage 34b is formed so as to bypass 1, and a primary side intake relief valve 35b (intake relief valve) configured as a butterfly valve is disposed in the relief passage 34b.

The pressure chamber of the actuator 29 that operates the exhaust leak valve 30 is connected via a conduit 36 to the blower 11 of the branch passage 10 in which the blower 11 of the primary turbocharger 4 is disposed.
It is communicated downstream (upstream of the relief passage 34b). When the pressure on the downstream side of the blower 11 exceeds a predetermined value, the actuator 29 is activated and the exhaust leak valve 30 is activated.
opens, whereby a small amount of exhaust gas flows into the exhaust leakage passage 28 and is supplied to the secondary turbine 7 when the exhaust cut valve 23 is closed. Therefore, the secondary turbo supercharger 6 starts rotating in advance before the exhaust cut valve 23 opens.

The pressure chamber of the actuator 33 that operates the intake cut valve 32 is connected to an electromagnetic solenoid type three-way valve 38 via a conduit 37.
connected to the output port of the

Further, the actuator 31 that operates the exhaust cut valve 23 is a differential pressure type actuator that is operated by a difference in pressure acting on two pressure chambers, and one pressure chamber is connected to an electromagnetic solenoid type actuator via a conduit 39a. is connected to the output port of another three-way valve 40a, and the other spring 3
The pressure chamber 1a is connected to the output port of another electromagnetic solenoid type three-way valve 40b through a conduit 39b. Furthermore, the pressure chamber of the actuator 41H that operates the secondary side intake relief valve 35a is connected to the output port of another electromagnetic solenoid type three-way valve 43a through a conduit 42a. Secondary side intake relief valve 35a
As will be described later, the relief passage 34a remains open until a predetermined time before the exhaust cut valve 23 and the intake cut valve 32 open.
Leave it open. Thereby, when the secondary turbocharger 6 is pre-rotated by the exhaust gas flowing through the exhaust leakage passage 28, the pressure upstream of the intake cut valve 32 is prevented from rising and entering a surging region.

On the other hand, the pressure chamber of the actuator 41b that operates the primary side intake relief valve 35b is connected to the output port of another electromagnetic solenoid type three-way valve 43b through a conduit 42b. The primary intake relief valve 35b is configured to adjust the amount of intake air pressurized by the blower 11 of the primary turbocharger 4 to be released, as will be described later.

The actuator 26 for operating the wastegate valve 27 is connected by a conduit 44 to the output port of another three-way valve 45 of the electromagnetic solenoid type.

Further, 55 is a battery, and 56 is an ignition switch provided on a harness that connects the battery 55 and the electrical system of the engine 1. When the ignition switch 56 is turned on, the current from the battery 55 or the electricity from the engine 1 is switched on. O of the starter (not shown)
Engine 1 is started by N operation. Also, when the ignition switch 56 is turned off, the battery 55
current is no longer supplied to the electrical system of the engine 1, and the engine 1 stops.

And the above six electromagnetic solenoid type three-way valves 38.40
a, 40b, 43a, 43b, 45 and the two fuel injection valves 19, 20 are controlled by a control unit 46 configured using a microcomputer. The control unit 46 includes an output signal of an engine rotation speed sensor 61 (engine rotation speed detection means), an output signal of a throttle valve opening sensor 62, an operation amount of an accelerator pedal 63, and an accelerator operation amount that detects the operation acceleration. Output signal of sensor 64 (load request detection means),
In addition to the output signal of the air flow meter 21 and the signal of the ignition switch 56 (detection of whether or not electricity is supplied), the manifold pressure PI downstream of the primary side blower 11
, the opening degree of the waste gate passage 25, etc. are input.

One manual port of the electromagnetic solenoid type three-way valve 38 for controlling the intake cut valve 32 is connected to a negative pressure tank 48 via a conduit 47, and the other manual port is connected to a differential pressure detection valve (described later) via a conduit 49. 50 output port door 0. Intake negative pressure downstream of the throttle valve 16 is introduced into the negative pressure tank 48 via a check valve 51.

Further, one input port of the three-way valve 40a for controlling the exhaust cut valve 23 is open to the atmosphere, and the other input port is a conduit connected to the downstream side of the blower of the primary supercharger 4 via a conduit 57. 36. and,
Similarly, one input port of the three-way valve 40b for controlling the exhaust cut valve is open to the atmosphere, and the other manual port is connected to the conduit 47 connected to the negative pressure tank 48 via the conduit 52. There is. Therefore, the actuator 31 that operates the exhaust cut valve 23 is operated by the differential pressure between the intake manifold pressure downstream of the primary side blower guided through the conduit 57 and the intake negative pressure guided through the conduit 52 and the conduit 47. Operate.

On the other hand, one manual port of the three-way valve 43a for controlling the secondary intake leaf valve 35a is connected to the negative pressure tank 48, and the other input port is open to the atmosphere. On the other hand, one input port of the three-way valve 43b for controlling the primary side intake leaf valve 35b is open to the atmosphere, and the other input port is connected to the conduit 36 communicating with the downstream side of the primary side blower 11 via a conduit 54a. has been done.

Further, one input port of the three-way valve 45 for controlling the wastegate valve 27 is open to the atmosphere, and the other input port is connected to the conduit 36 communicating with the downstream side of the primary blower 11 through a conduit 54b. .

The differential pressure detection valve 50 is in a state where the three-way valve 38 is turned on and the conduit 37 connected to the pressure chamber of the actuator 33 for operating the intake cut valve 32 is communicated with the conduit 49 connected to the output port of the differential pressure detection valve 50. Then, the pressure upstream of the intake cut valve 32 approaches the manifold pressure P2 on the secondary side or the manifold pressure P1 on the primary side, and the differential pressure Pl-P: disappears, and furthermore, the differential pressure P knee P becomes lower than the predetermined value. When the amount increases, the atmosphere is introduced into the actuator 33, and the intake cut valve 32 is opened. Also, three-way valve 3
8 is OFF and the above conduit 3 on the actuator 33 side
7 is connected to a conduit 47 leading to a negative pressure tank 48, negative pressure is supplied to the actuator 33, and the intake cut valve 32 is closed.

On the other hand, when the two three-way valves 40a and 40b for controlling the exhaust cut valve 23 are both OFF, the conduits 39a and 39b are opened to the atmosphere.
It is closed by the biasing force of the spring 31a of the actuator 31.

On the other hand, when both three-way valves 4.0a and 40b are turned on,
The conduit 39a is connected to one pressure chamber of the actuator 31.
The primary side manifold pressure PI is guided through
A conduit 3 is connected to the pressure chamber in which the other spring 31a is arranged.
Negative pressure is generated through 9b, and the actuator 31 receiving this relative pressure overcomes the high back pressure (exhaust dynamic pressure) acting on the exhaust upstream side of the exhaust cut valve 23.
The exhaust cut valve 23 opens quickly, and supercharging by the secondary turbo supercharger 6 is performed.

The secondary side intake relief valve 35a connects the conduit 42a connected to the pressure chamber of the actuator 41a for operating the secondary side intake leaf valve 35a to the negative pressure tank 48 when the three-way valve 43a for controlling the secondary side intake leaf valve 35a is OFF.
When the three-way valve 43 is turned on and the conduit 42 connected to the pressure chamber of the actuator 41 is released to the atmosphere, it is closed. On the other hand, the actuator 41b for operating the primary side intake leaf valve 35b is the three-way valve 4 for controlling the primary side intake leaf valve 35b.
When 3b is ON, the conduit 54a.

It communicates with the downstream side of the primary side blower 11 via 36, and is released to the atmosphere when this three-way valve 43b is OFF.

In addition, the actuator 26 for operating the West Kate valve 27
When the three-way valve 45 for controlling the waste gate valve 27 is ON, the primary side blower 11 is
It communicates downstream, and is released to the atmosphere when the three-way valve 45 is OFF.

In this embodiment, in order to prevent backflow of intake air to the secondary blower when the exhaust cut valve 23 closes and the intake cut valve 32 remains open during transition from the supercharging region to the non-supercharging region, the The intake cut valve 32 is forcibly closed after a predetermined time (for example, 2 seconds) has elapsed starting from the time when the exhaust cut valve 23 is closed.

Next, the control unit 46 controls. The control of the primary side intake relief valve 35b by the actuator 41b for operating the primary side intake leaf valve 35b and the control of the wastegate valve 27 by the actuator 29 for operating the wastegate valve 27 will be explained based on the free control shown in FIG.

FIG. 3 shows a flowchart for performing the above-described control.

First, in step S1 of FIG. 3, the system is initialized. Next, step S! The engine rotation speed Ne is read by the engine rotation speed sensor 61, and the accelerator pedal 63 is read by the accelerator operation amount sensor 64.
Read the operating acceleration α, throttle valve opening sensor 6
2, and the manifold pressure P1 downstream of the primary side blower 11 are read respectively.

Then, in step S3, the throttle valve opening degree TVO is determined with respect to the engine speed Ne shown in FIG.

From the characteristic map, a target manifold pressure Po that is an appropriate magnitude of the manifold pressure downstream of the primary side blower 11 is determined according to the operating state of the engine. Next, in step S4, the operating state of the engine is determined from the supercharging pressure control zone map shown in FIG. Determine whether it is a pressure control zone or an intake side boost pressure control zone. That is, in the normal operating state where the operating acceleration α of the accelerator pedal 63 is below a predetermined value, the wastegate valve 2
7 is determined to be the exhaust side supercharging pressure control zone where the opening and closing of the primary side intake relief valve 35b is controlled, while in the acceleration request driving state where the operating acceleration α of the accelerator pedal 63 is equal to or higher than a predetermined value, the intake side overcharging pressure control zone where the opening and closing of the primary side intake relief valve 35b is controlled is determined. It is determined that it is a supply pressure control zone.

Next, in step S5, it is determined whether or not the boost pressure control zone determined in step S4 is the exhaust side boost pressure control zone, and if this determination is YES that it is the exhaust side boost pressure control zone. In this case, the process proceeds to step S6 to check whether the previous time was also in the exhaust side supercharging pressure control zone, that is, whether the engine operating state has just changed from the intake side supercharging pressure control zone to the exhaust side supercharging pressure control zone. Determine. and,
In step S6, if the engine operating state has just changed from the intake side supercharging pressure control zone to the exhaust side supercharging pressure control zone and the previous time was NO, then step s7 Proceed to.

Then, in step S7, the primary side intake relief valve 3
5b is fully opened by the primary side intake leaf valve 35b operating actuator 41b.

Next, in step S8, the target manifold pressure Po obtained in step S3 is determined from the map shown in FIG.
The initial value [)exo of the drive duty ratio of the actuator 26 for operating the wastegate valve 27 corresponding to is determined.

That is, the standard drive duty ratio when the manifold pressure P1 downstream of the primary side blower 11 becomes the target manifold pressure Po is determined. Then, in step S9, the initial value Dexo of the drive duty ratio obtained in step S8 is set as the drive duty ratio Dex, and the process proceeds to step S+3.

On the other hand, when the determination in step S6 is that the engine was in the exhaust side boost pressure control zone last time, that is, the engine operating state is continuously in the exhaust side boost pressure control zone (YE).
In the case of S, the process advances to step S10. In step SIO, the actual manifold pressure P downstream of the primary side blower 11 detected in step S2 is
1 is the target manifold pressure P obtained in step S3 above.
Determine whether it is smaller than o, and check the actual manifold pressure P1
If YES is smaller than the target manifold pressure Po, the process proceeds to step Sl+, where the drive duty ratio Dex of the actuator 26 for operating the wastegate valve 27 is decreased by a predetermined amount, and the process proceeds to step S+3. On the other hand, it is determined in step SIO that the actual manifold pressure P1 is the target manifold pressure P.

If the answer is No, the process proceeds to step S+2, where the drive duty ratio Dex of the actuator 26 for operating the waste gate valve 27 is increased by a predetermined amount, and the process proceeds to step S+2.
Proceed to I3.

In step S+3, the above steps S 9 and S I+
, or the actuator 2 for operating the wastegate valve 27 based on the drive duty ratio Dex set in S+2.
6 to open and close the waste gate valve 27.

On the other hand, the determination in step S5 is
In the case of NO, which is the boost pressure control zone determined by or the intake side boost pressure control zone that is not the exhaust side boost pressure control zone,
Proceeding to step S14, it is determined whether the previous time was also in the intake side supercharging pressure control zone, that is, whether the engine operating state has just changed from the exhaust side supercharging pressure control zone to the intake side supercharging pressure control zone. . Then, in the case of No in step S14, where the engine operating state has just changed from the exhaust side boost pressure control zone to the intake side boost pressure control zone and was not in the intake side boost pressure control zone last time, Step S
Proceed to I5.

Then, in step S+5, the wastegate valve 27 is temporarily fully opened by the actuator 26 for operating the wastegate valve 27. Next, in step SI6, the initial value DinO of the drive duty ratio of the actuator 41b for operating the primary intake leaf valve 35b corresponding to the target manifold pressure Po obtained in step S3 is determined from the map shown in FIG. That is, the standard drive duty ratio when the manifold pressure P1 downstream of the primary side blower 11 becomes the target manifold pressure Po is determined. Then, in step SI7, step S1
The initial value Dino of the drive duty ratio obtained in step 6 is set as the drive duty ratio Din, and the process proceeds to step S2+. In this case, the temporary full-open operation of the wastegate valve 27 in step SI5 causes the manifold pressure P1 downstream of the primary side blower 11 to change to the target manifold pressure P1.
o, and when the manifold pressure PI downstream of the primary side blower 11 reaches the target manifold pressure Po, a predetermined control cane based on the accelerator operation acceleration α from the accelerator opening sensor 64 performs opening/closing control to start supercharging. The pressure characteristics are optimized.

On the other hand, when the determination in step S14 is that the previous time was also in the intake side boost pressure control zone, that is, the engine operating state is continuously in the intake side boost pressure control zone Y.
In the case of ES, the process advances to step S18. Then, in step S18, the actual manifold pressure P1 downstream of the primary side blower detected in step S2 is determined.
or the target manifold pressure Po obtained in step S3 above.
If the actual manifold pressure P1 is smaller than the target manifold pressure Po, the process proceeds to step SI9 and sets the drive duty ratio Din of the actuator 41b for operating the primary side intake leaf valve 35b. Decrease by a fixed amount and proceed to step S2+.

On the other hand, if the determination in step s1g is No, where the actual manifold pressure P is larger than the target manifold pressure Po, the process proceeds to step S20, where the drive duty ratio Din of the actuator 41b for operating the primary side intake leaf valve 35b is determined. is increased by a predetermined amount, and step S21
Proceed to.

In step S21, the primary-side intake leaf valve 35b operating actuator 41b is driven based on the drive duty ratio Din set in step S+7, SI9, or S20 to control the opening and closing of the primary-side intake relief valve 35b.

Therefore, steps S4 to S6 of the above flow
Accordingly, the driving state determining means 81 is configured to determine the normal driving state and the acceleration request driving state based on the engine speed Ne from the engine speed sensor 61 and the accelerator operation acceleration α from the accelerator operation amount sensor 64. There is. Further, the above steps S7 to S13,
Through steps 515 to S2+, the primary manifold pressure is adjusted so that the target manifold pressure corresponds to the accelerator opening acceleration α from the accelerator opening sensor 64 during normal operation, based on the operating state determined by the operating state determining means 81. While opening and closing the wastegate valve 27 is controlled with the side intake relief valve 35b open, the wastegate valve is controlled so that the target manifold pressure corresponds to the accelerator opening acceleration α from the accelerator opening sensor 64 in the acceleration request operation state. 27, the primary side intake relief valve 35b is temporarily fully closed until the manifold pressure P1 downstream of the primary side blower 11 reaches the target manifold pressure Po.
A supercharging pressure control means 82 is configured to control opening and closing.

Therefore, in the above embodiment, the engine rotation speed sensor 6
Based on the engine rotational speed Ne from 1 and the accelerator operation acceleration α from the accelerator operation amount sensor 64, the driving state determining means 81 determines the normal driving state and the acceleration request driving state, and based on this determination, in the normal driving state , the primary side intake relief valve 35b is fully opened, the amount of bypass intake air is increased, and the work of the primary supercharger 4 is reduced. In that case, the wastegate valve 27 is controlled to open and close by the wastegate valve 27 operating actuator 26 at the drive duty ratio Dex (predetermined control gain) based on the accelerator operation acceleration α of the accelerator operation amount sensor 64, and the wastegate valve 27 is controlled to open and close by the wastegate valve 27 operating actuator 26, Only the exhaust gas (energy) necessary for the manifold pressure P1 to become the target manifold pressure Po is supplied to the turbine 4, and the remaining exhaust gas is bypassed via the wastegate valve 27.
This results in a good fuel consumption rate with no waste in energy efficiency.

On the other hand, in the acceleration request operation state, the primary side blower 11
The waste gate valve 27 is temporarily closed until the downstream manifold pressure P1 reaches the target manifold pressure Po, and the entire amount of exhaust gas discharged from the engine is transferred to the primary supercharger 4.
The supercharger 4 is maintained in a state where the intake air can be pressurized by flowing through the turbine 5 of the supercharger 4. Therefore, when the primary side intake relief valve 35b is controlled to the closed side to reduce the bypass intake air amount with the drive duty ratio Din (predetermined control gain) based on the accelerator operation acceleration α of the accelerator operation amount sensor 64, the above manifold pressure P1 is On the other hand, when the primary side intake relief valve 35b is controlled to the open side to ensure a predetermined bypass intake amount (relief amount), the manifold pressure P1 immediately decreases. That is, by keeping the turbine 5 of the primary supercharger 4 in a pre-rotated state where it is always rotating and controlling the opening/closing of the intake relief valve 35b to adjust the amount of intake air bypass, the primary turbocharger can be prevented, especially when an acceleration request with an increased load is required. A target manifold pressure P at which a sufficient supercharging effect can be obtained from a state in which the manifold pressure P1 is being increased by pre-rotation of the feeder 4 (a state approaching the target manifold pressure P).

The system quickly shifts to the supercharging range, reducing the supercharging time lag and providing good response during acceleration-demanding operation.

As a result, the fuel consumption rate is improved during normal operation and during acceleration request operation. It is possible to achieve both improvement in response due to reduction in supercharging time lag at the time of acceleration request.

It should be noted that the present invention is not limited to the above embodiments, but includes various other modifications.

For example, in the above embodiment, the application is shown to be applied to a sequential turbo type exhaust turbo supercharged engine, but as shown in Fig. 8, it is applied to a single turbo type exhaust turbo supercharged engine. Of course, it is also good. In the figures, the same parts as in the above embodiment are denoted by the same reference numerals, and detailed explanation thereof will be omitted. The exhaust turbo supercharger is given the same reference numeral as that of the primary side exhaust turbo supercharger.

Further, in the above embodiment, the driving state determining means 81 determines whether the normal driving state or the acceleration request driving state is based on the operating acceleration α of the accelerator pedal 63 by the driver from the accelerator operating amount sensor 64.
Changes in the opening of the throttle valve are detected every very short period of time, and if the opening is greater than a predetermined value, a timer is activated so that the operating state determining means switches to control of the acceleration request operating state. You can also do it. It goes without saying that the normal driving state or the acceleration request driving state may be determined based on the 0N10FF signal of a kickdown switch provided in a vehicle equipped with an automatic transmission.

(Effects of the Invention) As described above, according to the control device for a supercharged engine according to the present invention, the target supercharging pressure corresponding to the detected value of the load request detection means is determined based on the determination of the operating state determination means. Become 1
In normal operating conditions, the intake relief valve is open and the wastegate valve is opened and closed to supply only the exhaust gas necessary to reach the target boost pressure to the turbine 4, thereby controlling the boost pressure and reducing wasted energy efficiency. On the other hand, in the acceleration request operation state, the wastegate valve is temporarily closed to keep the intake air pressurized, and the intake relief valve is opened and closed to immediately control the boost pressure by increasing or decreasing the bypass intake air amount. This improves the fuel consumption rate during normal operation and during acceleration request operation.

It is possible to achieve both improvement in response due to reduction in supercharging time lag at the time of acceleration request.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention. 2 to 7 show embodiments of the present invention,
Figure 2 is an overall configuration diagram of a supercharged engine, Figure 3 is a flowchart showing the opening/closing control of the wastegate valve and primary side intake relief valve in normal operating conditions and acceleration request operating conditions, and Figure 4 is engine rotation. Figure 5 is a map diagram for determining the target manifold pressure from the characteristics of the throttle valve opening relative to the engine load. 7 is a map diagram for determining the initial value of the drive duty ratio of the wastegate valve and operating actuator, and FIG. 7 is a map diagram for determining the initial value of the drive duty ratio of the actuator for operating the primary side intake relief valve. Further, FIG. 8 is a diagram corresponding to FIG. 2 showing a modification of the embodiment. 1... Engine 4... Primary supercharger (exhaust turbo supercharger) 5...
- Turbine 11...Blower 27...Wastegate valve 35b...Primary side intake relief valve (intake relief valve) 46...Control unit 61...Engine rotation speed sensor (engine rotation speed detection means) 64 ...Accelerator operation amount sensor (load request detection means) 81...Operating state determination means 82...Supercharging pressure control means Po...Target manifold pressure (target supercharging pressure) P]...
・Manifold pressure downstream of the primary side blower (supercharging pressure) and 2 other people Figure 6 Figure 7 Cell building I7! I] Adeptness level figure number ↑ vote Manibor) scale 0 figure

Claims (1)

[Claims] (1) Supercharging the engine includes an engine rotation speed detection means for detecting the engine rotation speed, a load request detection means for detecting the engine load request, a turbine driven by exhaust gas, and a blower for pressurizing intake air. An exhaust turbo supercharger, a waste gate valve that adjusts the flow rate of exhaust gas to the turbine of the exhaust turbo supercharger, and an intake relief valve that adjusts the amount of intake air that bypasses the blower of the turbo supercharger. and a driving state determining means for determining a normal driving state and an acceleration request driving state based on both detection values detected by the engine rotation speed detecting means and the load request detecting means, and the driving state determining means Based on the operating state determined by, in normal operating state, the waste gate valve is opened and closed with the intake relief valve open so that the target boost pressure corresponds to the detected value detected by the load request detection means. While controlling the boost pressure, in the acceleration request operation state, the wastegate valve is operated until the boost pressure reaches the target boost pressure so that the target boost pressure corresponds to the detected value detected by the load request detection means. A control device for a supercharged engine, comprising a supercharging pressure control means for controlling supercharging pressure by opening and closing an intake relief valve in a temporarily closed state.