JPH05125946A - Boost pressure controller for internal combustion engine equipped with supercharger - Google Patents

Abstract

PURPOSE:To provide a boost pressure controller of an internal combustion engine equipped with a supercharger while enhancing driveability by providing a decelerating force proportional to an accelerating force that is increased by supercharging. CONSTITUTION:A boost pressure controller comprises a mechanical supercharger 3 disposed in the intake passage 2 of an internal combustion engine 1, a bypass passage 4 bypassing the supercharger 3, a supercharged air regulating valve 5 for opening and closing the passage 4, a step motor 6 for driving the regulating valve 5, and an ECU 7 for controlling the motor 6. The ECU 7 controls the opening of the supercharged air regulating valve 5 to reduce the opening with the internal combustion engine 1 generating negative torque. As the opening of the supercharged air regulating valve 5 is reduced, proportionately the workloads of the supercharger 3 are increased, whereby friction of the internal combustion engine 1 is increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a supercharging pressure control device for an internal combustion engine with a supercharger.

[0002]

2. Description of the Related Art Conventionally, as a boost pressure control device for an internal combustion engine with a supercharger, a supercharger arranged in an intake passage of the internal combustion engine, a bypass passage bypassing the supercharger, and an opening / closing of the bypass passage. A supercharging adjustment valve, a drive means for driving the adjustment valve, and a control device for controlling the means,
The set supercharging pressure according to the engine speed (engine speed) and the acceleration request signal (throttle opening of the throttle valve) is compared with the actual supercharging pressure in the intake duct. It is known that the supercharging pressure is controlled by controlling the opening of the supply adjusting valve (for example, Japanese Patent Laid-Open No. 58-170825). That is, this prior art is to control the supercharging pressure by controlling the opening degree of the supercharging adjustment valve according to the operating state of the vehicle.

[0003]

In such a conventional internal combustion engine with a supercharger, for example, an internal combustion engine with a supercharger having a displacement of 1.6 l, the displacement is, for example, 2. Although an acceleration force (high output) equivalent to that of a 5l naturally aspirated engine can be obtained, only 1.6l engine friction can be obtained during deceleration, so deceleration force (engine braking force) commensurate with acceleration force cannot be obtained. , There may be a feeling of free running.

The present invention was made in view of the above-mentioned conventional problems, and it is possible to obtain a deceleration force commensurate with the acceleration force improved by supercharging, thereby improving drivability. An object of the present invention is to provide a boost pressure control device for an internal combustion engine with a feeder.

[0005]

In order to solve the above problems, the present invention provides a mechanical supercharger arranged in an intake passage of an internal combustion engine, a bypass passage bypassing the supercharger,
A supercharging regulating valve for opening and closing the passage, a driving means for driving the regulating valve, and a control device for controlling the driving means are provided, and the opening degree of the supercharging regulating valve is controlled according to the operating state of the vehicle. In a supercharging pressure control device for an internal combustion engine with a supercharger for controlling supercharging pressure, the control device closes an opening of the supercharging adjustment valve in a state where the internal combustion engine is generating negative torque. It is configured to control to the side.

[0006] Preferably, the control device is configured to control the opening degree of the supercharging adjustment valve to the closing side according to the operating state of the vehicle in a state where the internal combustion engine is generating a negative torque. Has been

[0007]

In the supercharging pressure control device described above, the control device controls the opening of the supercharging adjustment valve to the closing side in the state where the internal combustion engine is generating negative torque. The degree of closing increases the work of the supercharger, which increases the friction of the internal combustion engine.

Further, since the control device controls the opening degree of the supercharging adjustment valve to the closing side according to the operating state of the vehicle while the internal combustion engine is generating negative torque, The work of the supercharger increases by the amount that the opening is closed, so that the friction of the internal combustion engine increases according to the operating state of the vehicle.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a supercharging pressure control system for an internal combustion engine with a supercharger according to a first embodiment of the present invention. As shown in the figure, this supercharging pressure control device includes a mechanical supercharger 3 arranged in an intake passage 2 of an internal combustion engine 1, a bypass passage 4 bypassing the supercharger 3, and a bypass passage 4 It includes a supercharging adjustment valve 5 for opening and closing, a step motor (driving means) 6 for driving the adjustment valve 5, and an ECU (control device) 7 for controlling the step motor 6 and the like. Internal combustion engine 1
The rotation of the crankshaft 1a is always transmitted to the rotating shaft 3a of the supercharger 3 via the pulley 8, the belt 9 and the pulley 10.

An air cleaner 1 is provided at the upstream end of the intake passage 2.
1 is provided. At the downstream end of the intake passage 2,
An intake manifold 12 is provided that guides intake air to the intake ports of each cylinder of the internal combustion engine 1. The supercharger 3 is arranged upstream of the throttle valve 13. The supercharger 3
A water cooling intercooler 14 that cools the intake air pressurized by the supercharger 3 is arranged in the intake passage 2 between the throttle valve 13 and the throttle valve 13. Cooling water circulating through a radiator 15 and a pipe 16 is pressure-fed to the water-cooling intercooler 14 by a water pump 17.

In the ECU 7, the engine speed NE detected by an NE sensor (not shown), the vehicle speed V detected by a vehicle speed sensor (not shown), and the supercharging downstream of the throttle valve 13 detected by a PB sensor 18 are performed. Signals indicating the supercharging pressure P ₂ on the upstream side of the throttle valve 13 detected by the pressure PB and the P ₂ sensor 19 and the throttle opening θTH of the throttle valve 13 detected by the throttle opening sensor 20 are input.

The ECU 7 is configured to perform the normal mode processing during steady running, acceleration, and the like. In the normal mode process, for example, when the supercharging pressure P ₂ or the PB upstream or downstream of the throttle valve 13 reaches the maximum boost pressure from the open control, supercharging pressure P ₂ or PB
Is switched to the feedback control for controlling the opening of the supercharging adjustment valve 5 so that the maximum charging pressure becomes the maximum supercharging pressure, and the actual opening of the supercharging adjustment valve 5 during the feedback control is set to the target opening determined by the operating state at that time. (This target opening degree is obtained by, for example, searching the table of the target opening degree θOBJ stored in the memory in the ECU 7 by tabulating the optimum target opening degree θOBJ determined by the engine speed NE and the throttle opening degree θTH. When it becomes smaller than the above, the feedback control is shifted to the open control for controlling the opening of the supercharging adjustment valve 5 to the target opening θOBJ.

Further, the ECU 7 enters the deceleration mode process while the internal combustion engine 1 is generating a negative torque, and controls the opening degree of the target supercharging adjustment valve 5 to the closing side according to the operating state of the vehicle. Is configured. Specifically, in this deceleration mode process, first, the target opening degree of the supercharging adjustment valve 5 is set according to the operating state of the vehicle (in the first embodiment, the engine speed NE and the throttle opening θTH). θcc is set, the opening of the supercharging adjustment valve 5 is open-controlled to this target opening θcc, and when a predetermined time has elapsed since the deceleration mode process was started, the target P ₂ is set according to the operating state of the vehicle.
The pressure is set, and the opening degree of the supercharging adjustment valve 5 is feedback-controlled so that the supercharging pressure P ₂ on the upstream side of the throttle valve 13 becomes the target P ₂ pressure.

As shown in FIGS. 2 to 5, the target opening θcc is an optimum target opening θcc which is determined by the engine speed NE and the throttle opening θTH, and is formed into a table.
It is set by searching a table of the target opening θcc stored in a memory (not shown). Here, in FIG.
It is a map that three-dimensionally represents a target opening degree θcc determined by NE and θTH. 3, 4 and 5 are respectively shown in FIG.
A two-dimensional representation of a part of the map shown in FIG.
4 is a map showing the target opening degree θcc determined by θTH when NE is 1500 rpm, FIG. 4 is when NE is 4000 rpm, and FIG. 5 is when NE is 6500 rpm.

As is apparent from FIG. 2, in a region where the throttle opening θTH is extremely low, the target opening θcc is closed by a predetermined amount, and this closing angle changes according to the engine speed NE. Specifically, for example, when NE = 1500 rpm (see FIG. 3), the target opening θcc is fully open in a region where the throttle opening θTH is extremely low, and NE = 4000r.
At pm (see FIG. 4), when θTH is in a very low opening region, the target opening θcc changes to the closing side as θTH becomes the closing side, and when NE = 6500 rpm (see FIG. 5). , ΘTH is in a very low opening region, the target opening θcc changes to the closing side with a gentler gradient than in the case of Fig. 4 as θTH becomes the closing side, and the closing angle of θcc when θTH is fully closed is It is smaller than the case of 4. On the other hand, generally, in the conventional supercharging pressure control device, as shown in FIG. 18, the opening of the supercharging adjustment valve is related to the engine speed NE in the region where the throttle opening θTH is very low. It is fully open.

The tables of the target opening θcc shown in FIGS. 2 to 5 are prepared based on FIGS. 9 and 10. Figure 9
For example, the difference between the friction of an internal combustion engine having a displacement of 2.5 l and the friction of an internal combustion engine having a displacement of 1.6 l changes according to the engine speed NE. Due to this difference in friction, an internal combustion engine with a supercharger, for example, an internal combustion engine with a displacement of 1.6 l, has an acceleration force (high output) equivalent to that of a naturally aspirated engine with a displacement of 2.5 l, for example. However, the deceleration force (engine braking force) commensurate with the acceleration force cannot be obtained during deceleration. Therefore, the supercharger 3 is caused to work in order to compensate for the difference in friction at the time of deceleration. However, the required P ₂ pressure representing the required amount of work of the supercharger 3 and the required P ₂ pressure for obtaining this required P ₂ pressure are required. The target opening θcc of the feed adjustment valve 5 is shown in FIG. The target P ₂ pressure and the target opening θcc in FIG.
It corresponds when θTH is fully closed.

The target P ₂ pressure is an optimum target P ₂ pressure which is determined by the engine speed NE and the throttle opening θTH as a table as shown in FIGS.
It is set by searching the table of the target P ₂ pressure stored in the memory (not shown) in U7. The table of the target P ₂ pressure is created based on FIGS. 9 and 10 like the target opening θcc.

Next, the operation of the supercharging pressure control system for an internal combustion engine with a supercharger according to the first embodiment having the above construction will be described.

First, the ECU 7 executes the main routine of the supercharging control process shown in FIG. In this main routine, first, the engine speed NE detected by the NE sensor (not shown), the throttle opening θTH detected by the throttle opening sensor 20, the vehicle speed V detected by the vehicle speed sensor (not shown), etc. are read. (Step 101).

Next, the routine proceeds to step 102, where it is judged if the throttle opening θTH is equal to or less than a predetermined function f (NE) with respect to NE set as shown in FIG. This function f
(NE) is set within the region where the engine 1 produces a negative torque based on the characteristics of the internal combustion engine 1. If θTH is f (NE) or less, by controlling θcc to the closing side, , The absolute value of the negative torque becomes large.

The determination result of step 102 is negative (N
o), that is, when θTH is larger than f (NE), it is determined that the vehicle is running normally or accelerating, and the routine proceeds to step 103, where the control mode determination flag F-DEC is set to 0.
After that, the routine proceeds to step 104, the normal mode processing is executed, and the processing is ended.

In this normal mode process, the supercharging pressure is controlled by controlling the opening degree of the supercharging adjustment valve 5 according to the operating condition of the vehicle. For example, when the supercharging pressure P ₂ or PB has reached the maximum boost pressure from the open control, supercharging pressure P ₂ or PB to control the opening of the supercharging control valve 5 so as to maximize the boost pressure When shifting to the feedback control and the actual opening of the supercharging adjusting valve 5 during the feedback control becomes smaller than the target opening θOBJ determined by the operating state at that time, the supercharging adjusting valve 5 is opened from the feedback control. Degree to the target opening θOBJ
Move to open control, which is controlled to.

The answer to step 102 is affirmative (Yes
s), that is, when the throttle opening θTH is f (NE) or less, the routine proceeds to step 105, where it is determined whether the engine speed NE is a predetermined engine speed NELMT (for example, 1500 rpm) or more. When this determination result is negative (No), that is, NE is smaller than NELMT, the process proceeds to step 103. When the determination result of step 105 is affirmative (Yes), that is, when NE is NELMT or more, the routine proceeds to step 106, where it is determined whether the vehicle speed V is 0 or not. When this determination result is affirmative (Yes), that is, when the vehicle is stopped and the vehicle speed is 0, the process proceeds to step 103. When the determination result of step 106 is negative (No), that is, when the vehicle speed V is not 0, it is determined that the internal combustion engine 1 is generating a negative torque, the process proceeds to step 107, and the deceleration mode process is executed.

As described above, θTH is f (NE) or less,
When NE is NELMT or more and the vehicle speed V is not 0,
The deceleration mode process is executed by determining that the internal combustion engine 1 is generating a negative torque.

This deceleration mode process is executed by a subroutine of the deceleration mode process shown in FIG. In this subroutine, first, in step 301, it is determined whether the control mode determination flag F-DEC is 1. At this time, F-DEC is set to 0 in step 103 shown in FIG.
Since it was set to, the determination result of step 301 is negative (N
o), the process proceeds to step 302 to start the timer (timer setting), and further proceeds to step 303 to set F-DEC to 1. After this, step 30
4, the target opening degree θcc of the supercharging adjustment valve 5 is set according to the engine speed NE and θTH by searching the table of the target opening degree θcc (see FIGS. 2 to 5), and further steps are performed. The routine proceeds to 305, where the opening degree of the supercharging adjustment valve 5 is open-controlled so that the opening degree of the supercharging adjustment valve 5 becomes the target opening degree θcc set in step 304, and the processing ends. At this time, if the answer to step 106 in FIG. 11 remains negative (No), that is, if it is determined that the internal combustion engine 1 is generating a negative torque, the deceleration mode process is continued. In order to do so, the process returns to step 301 in FIG.

At this time, since F-DEC is set to 1 in the previous step 303 of the deceleration mode process, the determination result in step 301 becomes affirmative (Yes), and the process proceeds to step 306 and the timer measures the predetermined time. It is determined whether or not is completed. When the result of this determination is negative (No), that is, when the counting of the predetermined time has not ended, the routine proceeds to steps 304 and 305 to continue the open control. On the other hand, the determination result of step 306 is affirmative (Yes), that is, when the counting of the predetermined time is finished,
In step 307, the supercharging pressure P ₂ on the downstream side of the throttle valve 13 detected by the P ₂ sensor 19 is read.
Next, in step 308, the target P ₂ pressure of the supercharging adjustment valve 5 according to the engine speed NE and the slot opening θTH is searched in the target P ₂ pressure table (see FIGS. 6 to 8). Set by Further, the process proceeds to step 309, the opening degree of the supercharging adjustment valve 5 is feedback-controlled so that the supercharging pressure P ₂ read at step 307 becomes the target P ₂ pressure, and the process ends.

In this way, in the deceleration mode process executed in the state where the internal combustion engine 1 is generating the negative torque, first, the opening degree of the supercharging adjustment valve 5 is open-controlled to the target opening degree θcc, After a lapse of a predetermined time from the start of the deceleration mode process, feedback control of the opening degree of the supercharging adjustment valve 5 is performed so that the supercharging pressure P ₂ becomes the target P ₂ pressure. The degree is controlled to the closing side according to the operating state of the vehicle (in the first embodiment, the engine speed NE and the throttle opening θTH). As a result, the work of the supercharger 3 is increased by the amount by which the opening degree of the supercharging adjustment valve 5 is closed, the friction of the internal combustion engine 1 is increased, and as a result, the engine braking force is increased and the deceleration force commensurate with the acceleration force. Is obtained.

According to the above embodiment, in the deceleration mode process, the open control is first performed, and the feedback control is performed after a predetermined time has elapsed from the start of the deceleration mode process. Overshoot can be prevented.

Next, a supercharging pressure control device according to a second embodiment of the present invention will be described with reference to FIGS. 14 to 17.

In the second embodiment, the ECU 7 performs the target supercharging adjustment in the deceleration mode process executed when it is determined that the internal combustion engine 1 is generating the negative torque as described above. The opening degree of the valve 5 is configured to be controlled to the closing side according to the operating state of the vehicle (engine speed NE and gear stage). Specifically, in this deceleration mode process, first, the target opening degree θcc of the supercharging adjustment valve 5 is set according to the engine speed NE and the gear stage, and the opening degree of the supercharging adjustment valve 5 is set to this target opening degree θcc. Open control is performed, and when a predetermined time has elapsed after the deceleration mode process is started, the target P ₂ pressure is set according to the engine speed NE and the gear, and the supercharging pressure P ₂ on the upstream side of the throttle valve 13 is set. The feedback control of the opening degree of the supercharging adjustment valve 5 is performed so that the pressure becomes the target P ₂ pressure.

As shown in FIG. 16, the target opening θcc is a target opening which is stored in a memory (not shown) in the ECU 7 as a table of the optimum target opening θcc determined by the engine speed NE and the gear position. It is set by searching the table of θcc. The table of the target opening θcc is also created based on FIGS. 9 and 10 above.

In addition, in this second embodiment, in order to improve the feeling during deceleration, as is clear from FIG. 16, when the gear is in the second speed or lower, it is more than in the third speed or higher. Also, by changing the target opening θcc toward the open side, the amount of increase in friction is set to be small and the amount of increase in deceleration force (engine braking force) is set to be small.

As the target P ₂ pressure, as shown in FIG. 17, an optimum target P ₂ pressure determined by the engine speed NE and the gear stage is tabulated and stored in a memory (not shown) in the ECU 7. It is set by searching the P ₂ pressure table. The table of the target P ₂ pressure is also created based on FIGS. 9 and 10 like the target opening θcc. As for the target P ₂ pressure as well as the target opening θcc, when the gear is the second speed or lower,
By changing the target P ₂ pressure on the lower side than in the case of the third speed or higher, the amount of increase in friction is set small and the amount of increase in deceleration force (engine braking force) is set small.

Next, the operation of the supercharging pressure control system for the internal combustion engine with a supercharger according to the second embodiment will be described.

First, the ECU 7 executes the main routine of the supercharging control process shown in FIG. In this main routine, first, the engine speed NE detected by the NE sensor (not shown), the throttle opening θTH detected by the throttle opening sensor 20, the vehicle speed V detected by the vehicle speed sensor (not shown), etc. are read. (Step 401).

Next, in step 402, it is determined whether the throttle opening θTH is less than or equal to a predetermined throttle opening θLMT. When this determination result is negative (No), that is, when θTH is larger than θLMT, it is determined that the vehicle is running normally or accelerating, and the routine proceeds to step 403, where the control mode determination flag F-DEC is set to 0. After this, step 404
Then, the process proceeds to step S21 to execute the normal mode process, and ends the process.

The answer to step 402 is affirmative (Yes
s), that is, when the throttle opening θTH is less than or equal to the predetermined throttle opening θLMT, the routine proceeds to step 405, where the engine speed NE is the predetermined engine speed NELMT (for example,
(1500 rpm) or higher is determined. When this determination result is negative (No), that is, NE is smaller than NELMT, the process proceeds to step 403. On the other hand, when the determination result of step 405 is affirmative (Yes), that is, when NE is NELMT or more, the routine proceeds to step 406, where it is determined whether the vehicle speed V is 0 or not. When this determination result is affirmative (Yes), that is, when the vehicle is stopped and the vehicle speed is 0, the process proceeds to step 403.

On the other hand, when the determination result of step 406 is negative (No), that is, when the vehicle speed V is not 0, step 4
In step 07, it is determined whether the fuel cut is being performed (F / C is being performed). When the determination result is affirmative (Yes), that is, when the fuel cut is being performed, it is determined that the internal combustion engine 1 is decelerating (the internal combustion engine 1 is in the state of generating a negative torque), and the process proceeds to step 409. .. On the other hand, when the determination result of step 407 is negative (No), the routine proceeds to step 408, where it is determined whether or not leaning is under way (during KLS). When this determination result is negative (No), the process proceeds to step 403. On the other hand, when the determination result of step 408 is affirmative (Yes), it is determined that the internal combustion engine 1 is decelerating (the internal combustion engine 1 is in the state of generating negative torque), and the process proceeds to step 409. move on.

Thus, θTH is less than θLMT, and NE
Is equal to or higher than NELMT, the vehicle speed V is not "0", and the fuel cut or lean is being performed, the internal combustion engine 1 is decelerating (the internal combustion engine 1 is generating a negative torque). 409) and step 409
And executes deceleration mode processing.

The deceleration mode process of the second embodiment is shown in FIG.
This is executed by the deceleration mode processing subroutine shown in FIG. In this subroutine, first, the gear stage determination means (not shown) determines the gear stage currently in use (step 5).
01). Next, in step 502, it is determined whether the control mode determination flag F-DEC is 1. At this time, since F-DEC is set to 0 in step 403 of FIG. 14, the determination result of step 502 is negative (No).
Then, the process proceeds to step 503 to start the timer (timer setting), and further proceeds to step 504 to set F-DEC to 1. After that, the routine proceeds to step 505, where the target opening θcc of the supercharging adjustment valve 5 is set according to the engine speed NE and the gear determined in step 501 by referring to the table of the target opening θcc (see FIG. 16). The value is set by searching, and the process proceeds to step 506. The opening of the supercharging adjustment valve 5 is open-controlled so that the opening of the supercharging adjustment valve 5 becomes the target opening θcc set in step 505, and then the process ends. To do. At this time, the step 407 of FIG.
Alternatively, if the determination result of step 408 remains affirmative (Yes), it is determined that the internal combustion engine 1 is decelerating (the internal combustion engine 1 is generating a negative torque), and the deceleration mode process is executed. To continue.

In this case, after the execution of step 501 in FIG. 15, the process proceeds to step 502. At this time, in the previous deceleration mode process, in step 504, the F-DE
Since C has been set to 1, the determination result of step 502 is affirmative (Yes), and the routine proceeds to step 507, where it is determined whether or not the timer has finished counting the predetermined time. When the result of this determination is negative (No), that is, when the counting of the predetermined time has not ended, the step 505 is executed, the process proceeds to the step 506, and the open control is continued. On the other hand, when the determination result of step 507 is affirmative (Yes), that is, when the counting of the predetermined time is completed,
In step 508, the supercharging pressure P ₂ on the downstream side of the throttle valve 13 detected by the P ₂ sensor 19 is read.
Next, the routine proceeds to step 509, where the target P ₂ pressure of the supercharging adjustment valve 5 is set in the table of the target P ₂ pressure according to the engine speed NE and the gear determined in step 501 (see FIG. 17).
(See) to set it. Further, the routine proceeds to step 510, where the opening degree of the supercharging adjustment valve 5 is feedback controlled so that the supercharging pressure P ₂ read at step 508 becomes the target P ₂ pressure set at step 509.

In this way, in the deceleration mode process executed by determining that the internal combustion engine 1 is decelerating (the internal combustion engine 1 is generating a negative torque), first the supercharging adjustment is performed. The opening degree of the supercharging adjustment valve 5 is controlled such that the opening degree of the valve 5 is open-controlled to the target opening degree θcc, and the supercharging pressure P ₂ becomes the target P ₂ pressure after a predetermined time has elapsed from the start of the deceleration mode process. By performing feedback control of the above, the opening degree of the supercharging adjustment valve 5 is controlled to the closing side according to the operating state of the vehicle (in this second embodiment, the engine speed NE and the gear stage). As a result, the work of the supercharger 3 is increased by the amount by which the opening degree of the supercharging adjustment valve 5 is closed, and the friction of the internal combustion engine 1 is increased. As a result, the deceleration force (engine braking force) is increased.
Is increased to obtain deceleration force commensurate with acceleration force.

Even in the second embodiment, in the deceleration mode process, the open control is first performed, and the feedback control is performed after a predetermined time has elapsed from the start of the deceleration mode process. Shoots can be prevented.

Further, in this second embodiment, as described above, θTH is θLMT or less, NE is NELMT or more,
The internal combustion engine 1 is decelerating (the internal combustion engine 1 is generating a negative torque) only when the vehicle speed V is not "0" and the fuel is being cut or is leaning. Since the judgment is made and the deceleration mode process is executed, there is no increase in fuel consumption, which is preferable in practice.

Further, in each of the above embodiments, the engine speed NE is detected by an NE sensor (not shown), but the engine speed NE may be calculated from the vehicle speed V, the gear ratio and the like.

In each of the above embodiments, the throttle valve 1
Although the throttle opening θTH of No. 3 is detected by the throttle opening sensor 20, for example, the intake air amount on the upstream side of the throttle valve 13 detected by an air flow meter (not shown), the intake air temperature on the upstream side, and the supercharging The throttle opening θTH may be calculated from the pressures P ₂ , PB and the like.

[0048]

As described above, according to the present invention (Claim 1), the control device closes the opening degree of the supercharging adjustment valve while the internal combustion engine is generating negative torque. Therefore, the work amount of the supercharger is increased by the amount by which the opening degree of the supercharging adjustment valve is closed, which increases the friction of the internal combustion engine. Therefore, the engine braking is increased, and the deceleration force commensurate with the acceleration force improved by the supercharging is obtained, thereby improving the drivability.

Further, according to the present invention (Claim 2), the control device closes the opening degree of the supercharging adjustment valve in accordance with the operating state of the vehicle while the internal combustion engine is generating a negative torque. Since the control is performed to the side, the work of the supercharger increases by the degree to which the opening degree of the supercharging adjustment valve is closed, so that the friction of the internal combustion engine increases according to the operating state of the vehicle. Therefore, the engine brake is increased according to the driving state of the vehicle, and the deceleration force commensurate with the acceleration force improved by the supercharging is obtained, whereby the drivability is further improved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a supercharging pressure control device for an internal combustion engine with a supercharger according to a first embodiment of the present invention.

FIG. 2 is a three-dimensional map showing a target opening determined by an engine speed and a throttle opening.

FIG. 3 is a two-dimensional representation of a part of the map shown in FIG. 2, which is a map when the engine speed is 1500 rpm.

FIG. 4 is a two-dimensional representation of a part of the map shown in FIG. 2, which is a map when the engine speed is 4000 rpm.

5 is a two-dimensional representation of a part of the map shown in FIG. 2, and is a map when the engine speed is 6500 rpm.

FIG. 6 is a map showing a target P ₂ pressure which is determined by an engine speed and a throttle opening, and is a diagram when the engine speed is 1500 rpm.

FIG. 7 is a map similar to FIG. 6, showing an engine speed of 40.
It is a figure at the time of 00 rpm.

FIG. 8 is a map similar to FIG. 6, showing an engine speed of 65.
It is a figure at the time of 00 rpm.

FIG. 9 is a graph showing how the difference between the friction of an internal combustion engine having a displacement of 2.5 l and the friction of an internal combustion engine having a displacement of 1.6 l changes according to the engine speed.

10 is a necessary P ₂ pressure (target P ₂ pressure) representing the work of the supercharger required to compensate for the difference in friction shown in FIG. 9 and a supercharging adjustment valve for obtaining this required P ₂ pressure. It is a graph which shows a target opening.

FIG. 11 is a flowchart showing a main routine of a supercharging control process of the supercharging pressure control device according to the first embodiment.

FIG. 12 is a graph showing a predetermined function set with respect to the engine speed in a region where the internal combustion engine generates a negative torque.

FIG. 13 is a flowchart showing a deceleration mode process of the supercharging pressure control device according to the first embodiment.

FIG. 14 is a flowchart showing a main routine of a supercharging control process of the supercharging pressure control device according to the second embodiment.

FIG. 15 is a flowchart showing a deceleration mode process of the supercharging pressure control device according to the second embodiment.

FIG. 16 is a map showing a target opening degree determined by an engine speed and a gear stage.

FIG. 17 is a map showing a target P ₂ pressure that is determined by the engine speed and gear.

FIG. 18 is a three-dimensional map showing a target opening degree determined by an engine speed and a throttle opening degree in a conventional supercharging pressure control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Intake passage 3 Mechanical supercharger 5 Supercharging adjustment valve 6 Step motor (drive means) 7 ECU (control device) 13 Throttle valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenichiro Kinoshita, 1-4-1 Chuo, Wako, Saitama, Ltd. Inside the Honda R & D Co., Ltd.

Claims (2)

[Claims] 1. A mechanical supercharger arranged in an intake passage of an internal combustion engine, a bypass passage bypassing the supercharger,
A supercharging regulating valve for opening and closing the passage, a driving means for driving the regulating valve, and a control device for controlling the driving means are provided, and the opening degree of the supercharging regulating valve is controlled according to the operating state of the vehicle. In a supercharging pressure control device for an internal combustion engine with a supercharger for controlling supercharging pressure, the control device closes an opening of the supercharging adjustment valve in a state where the internal combustion engine is generating negative torque. 1. A supercharging pressure control device for an internal combustion engine with a supercharger, which is configured to be controlled to a side. 2. The control device is configured to control the opening degree of the supercharging adjustment valve to the closing side according to the operating state of the vehicle in a state where the internal combustion engine is generating negative torque. The supercharging pressure control device according to claim 1, wherein: