JPH0529768B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a supercharging device for an internal combustion engine that includes an exhaust turbine supercharger and a mechanically driven supercharger.

[Conventional technology]

In recent years, in the automobile field, for example,
-No. 169240, No. 169239, No. 169239, No. 169239, No. 169240, No. 169239, No. 169240, No. 169239, No. 169239, No. 169240
As disclosed in No. 26235, Utility Model Application Publication No. 61-132444, etc., an exhaust turbine type supercharger that uses the exhaust gas of an internal combustion engine (hereinafter abbreviated as the engine) and a mechanical drive that uses the driving force of the engine. A supercharging device combining a supercharger and a supercharger has been proposed.

This type of supercharging device has an exhaust turbine supercharger placed on the upstream side of the intake passage and a mechanically driven supercharger placed on the downstream side, and these turbochargers can be used together as needed. Alternatively, only the exhaust turbine type supercharger is driven, and supercharging is performed by effectively utilizing the advantages of both.

In other words, in general, the boost pressure characteristics of an exhaust turbine type supercharger are considered to be more advantageous in the high speed rotation range of the engine than in the low speed rotation range of the engine where the exhaust pressure decreases because the exhaust pressure is used. The type turbocharger is suitable for high-speed rotation areas that are susceptible to mechanical noise and vibration.
More stable supercharging pressure characteristics can be obtained in the low speed rotation range where these effects are not as great.

Therefore, in order to effectively utilize the advantages of both systems, this type of supercharging system uses an exhaust turbine supercharger to assist the engine when supercharging is required and the engine speed is below a predetermined value. Therefore, a system is adopted in which the mechanically driven supercharger is operated, but when the engine reaches a high speed range above a predetermined value, the mechanically driven supercharger is stopped and only the exhaust turbine supercharger is operated. are doing.

As described above, in this type of supercharging system, the operation of the mechanically driven supercharger is stopped when the engine reaches a predetermined rotational speed (hereinafter, the engine rotational speed at this time is set to the supercharger cutoff). In this case, if no consideration is given, the supercharging pressure will decrease by the amount that the mechanically driven supercharger is stopped.

Therefore, conventionally, as disclosed in Utility Model Application Publication No. 61-169240, etc., a wastegate actuator that adjusts the output of the exhaust turbine has been used to control the boost pressure on the upstream side of the mechanically driven supercharger. Introducing it as pressure, or Utility Model Application Publication No. 169239/1983, No. 132444/1983
As disclosed in the above publication, the intake manifold internal pressure on the downstream side of the mechanically driven supercharger (throttle valve downstream pressure) is introduced into the wastegate actuator as control pressure, and the control pressure is Based on this, the wastegate opening force is instantly weakened by an amount equal to the pressure drop when the mechanically driven supercharger stops, thereby increasing the output of the exhaust turbine supercharger and reducing the drop in supercharging pressure. prevent, etc.
Various measures are being taken.

[Problem to be solved by the invention]

By the way, the boost pressure in the intake passage is subject to ventilation resistance from the passage, throttle valve, intercooler, etc.
For supercharging pressure control after the mechanically driven supercharger stops as described above, ideally, the final intake manifold internal pressure after experiencing these ventilation resistances is introduced to the wastegate actuator as control pressure. However, it is ideal to control the boost pressure based on this control pressure.

From this point of view, among the boost pressure control methods mentioned above, the latter method in which the pressure on the downstream side of the throttle valve is introduced into the wastegate actuator as a control pressure on the downstream side of the mechanically driven supercharger. something that satisfies this condition.

However, in the case of this boost pressure control method, even if the compressor outlet pressure of the exhaust turbine supercharger exceeds a predetermined pressure during partial load when the opening degree of the throttle valve is not large enough, the If the side pressure is low, the wastegate actuator may still maintain a weak opening force of the wastegate, and as a result, the wastegate may not open and the exhaust turbine supercharger may exceed the allowable rotation speed. In addition, both positive and negative pressure are applied to the diaphragm of the wastegate actuator depending on the operating condition, and as a result, the load on the diaphragm increases, increasing the degree of fatigue of the diaphragm and causing the wastegate actuator to tended to shorten the lifespan of

On the other hand, in the former case, since the control pressure of the wastegate actuator is led from upstream of the mechanically driven supercharger, there are points that need to be improved in order to improve the control accuracy of the supercharging pressure.

The present invention has been made in view of the above points, and its purpose is to improve the accuracy of boost pressure control in a supercharging device equipped with an exhaust turbine type supercharger and a mechanically driven supercharger, and to It is an object of the present invention to provide a supercharging device that can reduce the load applied to the supercharging device and improve its life.

[Means to solve the problem]

The present invention is basically constructed as follows (note that the reference numbers attached to the constituent elements are taken from the embodiments in FIGS. 1 and 3 for the sake of easy understanding of the content. be).

That is, the present invention provides an intake passage 2 for an internal combustion engine.
is equipped with an exhaust turbine type supercharger 4 and a mechanically driven supercharger 5 located downstream thereof, and when supercharging is required and the engine speed Ne is less than a predetermined value Ne ₀ , the exhaust turbine type Both the supercharger 4 and the mechanically driven supercharger 5 are operated for supercharging, and when the engine speed Ne reaches Ne ₀ or more, the supercharging operation of the mechanically driven supercharger 5 is stopped and the exhaust turbine type supercharger is activated. This is a supercharging device that switches to supercharging operation of the charger 4 alone, and the exhaust passage 3 of the internal combustion engine has a waste gate 1 that allows part of the exhaust gas to bypass the exhaust turbine 4a of the exhaust turbine supercharger.
In a supercharging device provided with a bypass 17 with an 8-tube, the throttle valve 7 of the intake passage 2 is arranged downstream of the mechanically driven supercharger 5, and the wastegate actuator 19 is arranged downstream of the mechanically driven supercharger 5. A means 13b for detecting the throttle valve upstream supercharging pressure P2 near the throttle valve 7 on the downstream side, and adjusting the valve opening force of the waste gate 18 so that the throttle valve upstream supercharging pressure P2 becomes the set supercharging pressure P ₀ '. Mechanisms 19a, 19b
A bypass 8 with a valve 9 that bypasses the mechanically driven supercharger 5 is provided in the intake passage 2, and a bypass valve control device 1 that controls the opening and closing of this valve 9.
0 includes at least a means for opening the valve 9 so that the bypass 8 enters the bypass mode during independent supercharging operation of the exhaust turbo supercharger 4, and a means 13a for detecting the supercharging pressure P1 downstream of the throttle valve 7.
and an exhaust turbo supercharger 4 and a mechanically driven supercharger 5
During both supercharging operations, when the downstream supercharging pressure P1 of the throttle valve becomes less than the set value _P0 , the valve 9 is closed, and when it becomes more than the set value _P0 , the valve 9 is opened, and the throttle is set to the set value Po as the target value. It consists of a means for controlling the boost pressure P1 downstream of the valve, and when the valve 9 is opened in the throttle valve downstream boost pressure P1 control (that is, when P1 becomes equal to or higher than Po and the valve 9 opens). , a bypass 8 transfers a portion of the supercharging air downstream of the mechanically driven supercharger 5 to the mechanically driven supercharger 5.
It was designed to double as a relief passageway returning upstream.

[Operation] When both the exhaust turbine supercharger 4 and the mechanically driven supercharger 5 are in operation (supercharging operation), the bypass valve control device 10 detects the supercharging pressure P1 downstream of the throttle valve 7. Then, the bypass valve 9 of the mechanically driven supercharger 5 is controlled to open and close so that P1 becomes the target value Po.

In other words, when the boost pressure P1 downstream of the throttle valve 7 becomes less than the set value _P0 , the valve 9 closes, and when it becomes more than the set value _P0 , the valve 9 opens, which is repeated so that P1 becomes the target value Po. controlled.

In this case, when P1 becomes equal to or higher than Po and the valve 9 opens, the bypass 8 directs a part of the supercharged air downstream of the mechanically driven supercharger 5 to the upstream side of the mechanically driven supercharger 5 via the bypass 8. It has a so-called relief effect.

This supercharging pressure P1 control controls the supercharging pressure downstream of the throttle valve after the ventilation resistance element such as the throttle valve 7, so it is possible to control the supercharging pressure of intake air supplied to the engine with high precision, and Bypass 8 for detecting the throttle valve downstream boost pressure P1 and adjusting P1
Since the bypass 8 is placed in the mechanically driven supercharger 5 downstream of the exhaust turbine supercharger 4, the positions of the two are close to each other, reducing the time lag between them and improving the response of supercharging pressure P1 control. Speed up sex.

Next, when the engine shifts from the above operating state to high speed rotation, the supercharging operation of the mechanically driven supercharger 5 is stopped and the supercharging operation of the exhaust turbine supercharger 4 is switched to independent supercharging operation. In this case, the bypass 8 is in the open mode, and the exhaust turbine supercharger 4
The supercharging air fed from the engine is supplied to the engine via the bypass 8.

Then, the supercharging pressure tends to decrease by the amount of supercharging from the mechanically driven supercharger 4, but in this case, the wastegate actuator 1
9 is a throttle valve 7 on the downstream side of the mechanically driven supercharger 5.
The waste gate 18 detects the nearby throttle valve upstream supercharging pressure P2 and adjusts the waste gate so that P2 becomes the set supercharging pressure _P0 '.
Adjust the opening force of the valve.

That is, wastegate actuator 1
9 indicates signs of a decrease in boost pressure by checking the boost pressure upstream of the throttle valve.
P2 is detected, the valve opening force of the waste gate 18 is adjusted, and as a result, the output of the exhaust turbine supercharger 4 is increased to maintain P2 at the set supercharging pressure P ₀ '.

Further, if the exhaust turbine supercharger 4 continues to operate independently from the above state, the bypass 8 is in the open mode, so the wastegate actuator 19
However, on the downstream side of the mechanically driven supercharger 5, the throttle valve upstream supercharging pressure P2 near the throttle valve 7 is detected, and the valve opening force of the waste gate 18 is adjusted so that P2 becomes the set supercharging pressure P ₀ '. adjust.

This P2 supercharging pressure control is performed by detecting the supercharging pressure upstream from the detection position of the supercharging pressure P1, but it is still performed at a position close to the throttle valve 7, so
To ensure accurate boost pressure control with almost no fluctuation in boost pressure supplied to an internal combustion engine.

The supercharging pressure control by detecting the supercharging pressure P2 adjusts the opening degree of the waste gate 18, thereby preventing the exhaust turbine from over-rotating when the exhaust pressure increases. Therefore, not only can the exhaust turbine type supercharger 4 be operated independently, but also when the above-mentioned supercharging pressure P1 control is performed (both the exhaust turbine type supercharger 4 and the mechanically driven supercharger 5 are operated). ), but the following may be used instead:

That is, as shown in FIG. 3, in addition to the means 13 for detecting the throttle valve upstream supercharging pressure P2 near the throttle valve 7, the wastegate actuator 19 is equipped with an exhaust turbine supercharger 4 and a mechanically driven supercharger. A means 21 for detecting the supercharging pressure P3 near the compressor outlet of the exhaust turbine supercharger 4 between the engine 5 and a switching means 20 for selectively taking in the supercharging pressures P2 and P3 to be detected are added. By the switching control of this switching means 20, the wastegate actuator is
During independent supercharging operation of the exhaust turbine supercharger 4, the throttle valve upstream supercharging pressure P2 is taken in to adjust the valve opening force of the waste gate 18, and the exhaust turbine supercharger 4 and mechanically driven supercharger 5 are The supercharging pressure P3 on the exhaust turbine supercharger outlet side during both supercharging operations
The valve opening force of the waste gate 18 may be adjusted by incorporating the

In this way, when both the exhaust turbine type supercharger 4 and the mechanically driven type supercharger 5 are operated, the boost pressure P1 on the downstream side of the throttle valve is controlled, and the exhaust turbine type supercharger Since the outlet side supercharging pressure P3 of the exhaust turbine supercharger 4 is controlled, in addition to guaranteeing the accuracy of supercharging pressure control, it is possible to further improve the reliability of preventing overspeed of the exhaust turbine supercharger 4.

〔Example〕

Embodiments of the present invention will be described based on the drawings.

FIG. 1 is a configuration diagram of a supercharging system showing a first embodiment of the present invention.

In the figure, 1 is an internal combustion engine, 2 is an intake passage, 3 is an exhaust passage, 4 is an exhaust turbine supercharger, and 5 is a mechanically driven supercharger. An exhaust turbine 4a of the exhaust turbine supercharger 4 is arranged in the exhaust passage 3, and a compressor 4b driven by the exhaust turbine 4a is arranged in the intake passage 2. Mechanically driven supercharger 5
is arranged downstream of the compressor 4b of the exhaust turbine supercharger 4 in the intake passage 2, and further downstream of the mechanically driven supercharger 5 in the intake passage 2 is an intercooler 6, and an intercooler 6 is arranged downstream of the mechanically driven supercharger 5. A throttle valve 7 is arranged at.

Exhaust gas discharged from the engine 1 rotates a turbine 4a of an exhaust turbine supercharger 4 and is discharged into the atmosphere. On the other hand, the intake air is compressed by the compressor 4b of the exhaust turbine supercharger 4, and further compressed by the mechanically driven supercharger 5 when the mechanically driven supercharger 5 is in the driving state. After being cooled through the cooler 6, it is supplied to the engine 1 through the throttle valve 7.

The mechanically driven supercharger 5 is driven by the engine 1 via an electromagnetic clutch 11 and a power transmission means 12. The electromagnetic clutch 11 is controlled by a control unit 14, which will be described later.

Reference numeral 8 denotes a bypass that bypasses the mechanically driven supercharger 5. The bypass 8 is provided with a valve 9, and the valve 9 is operated by a bypass valve control device 10.

The bypass valve control device 10 has a detection tube 13a that detects the supercharging pressure P1 downstream of the throttle valve 7, and inside the device main body 10, an operation signal from the control unit 14 and supercharging pressure detection information from the detection tube 13a are stored. means for controlling opening and closing of the bypass valve 9 according to the operating state of the engine 1. Specifically, when the engine is in an idle state and the speed is higher than the supercharger cutoff speed, in other words, when the mechanically driven supercharger 5 is stopped (when the exhaust turbine supercharger 5 is operating independently), , means for fully opening the bypass valve 9 based on the operating signal from the control unit 14, and when supercharging is required and the engine speed is below the supercharger cutoff speed (exhaust turbine type 4 and mechanically driven supercharger 5), the bypass valve 9 is controlled to open and close in accordance with the pressure inside the manifold 15 (the throttle valve downstream boost pressure) P1 detected by the detection tube 13a. is the target boost pressure
and means for controlling so that P ₀ .

The control unit 14 has a function of inputting the rotational speed (rotation signal) of the engine 1 detected by the rotational speed detector 16 and driving the electromagnetic clutch 11 and the bypass valve control device 10 based on this rotational speed. The specific operation of the control unit 14 will be described later.

A bypass 17 bypasses the exhaust turbine 4a, and the bypass 17 is provided with a wastegate 18 whose opening and closing are controlled by a wastegate actuator 19. The wastegate actuator 19 has pressure (supercharging pressure) P2 downstream of the mechanically driven supercharger 5 and upstream of the throttle valve near the throttle valve 7.
is introduced, and this pressure P2 is applied to the working chamber 19 of the wastegate actuator 19 by the detection tube 13b.
By being introduced into a, the waste gate 18
The valve opening force (opening degree) of the valve is adjusted.

As the throttle valve upstream pressure P2 increases, the pressure in the control chamber 19a of the wastegate actuator 19 increases, and this pressure increases the opening force of the wastegate 18 via the operating rod 19b, and conversely P2
The lower the value, the smaller the opening force of the waste gate 19 becomes, and in this way the opening degree of the waste gate 18 is controlled.

Next, the operation of this embodiment will be explained based on the flowchart shown in FIG.

Step 100 in FIG. 2 is the start of a routine built into the control unit 14, which is activated at regular intervals by another operation. First, in step 101, the engine speed Ne is compared with a preset idle speed (Ne idle) to determine the idle state.

When the engine speed Ne is equal to or smaller than the set idle speed, that is, in the idle state, the control unit 14 turns off the electromagnetic clutch 11 to stop the operation of the mechanically driven supercharger 5 (step
103). Further, the process proceeds to step 106, where the bypass valve control device 10 is turned on and the bypass valve 9 is opened.

At this time, the air sent out from the exhaust turbine supercharger 4 which is in a low output state corresponding to the idle state bypasses the stopped mechanically driven supercharger 5 which has high ventilation resistance, It is supplied to the engine 1 through an intercooler 6 and a throttle valve 7.

Next, when the engine speed Ne becomes larger than the set speed (Ne > Ne idle), the speed Ne is compared with a preset supercharger cut-off speed Ne ₀ in step 102, and Ne≦Ne. ₀
At this time, the control unit 14 turns on the electromagnetic clutch 11.

At this time, both the exhaust turbine supercharger 4 and the mechanically driven supercharger 5 operate (supercharging operation), and the output of the exhaust turbine supercharger 4 in the low and medium speed range is transferred to the mechanically driven supercharger 4. It is supplemented by the output of supercharger 5. In this way, the engine 1 is at or above the idle speed and below the predetermined supercharger cutoff speed (Ne<Ne ₀ ).
Bypass valve control device 1
0 controls the opening and closing of the bypass valve 9 as follows so that the pressure P1 inside the intake manifold 15 becomes a predetermined value Po.

That is, when the exhaust turbine supercharger 4 and the mechanically driven supercharger 5 are operating, in step 105, the throttle valve downstream pressure P1 applied to the bypass valve control device 10 via the pressure detection pipe 13a is determined in advance. Compare with the set pressure Po. And P1
When it is below Po (P1≦Po), the bypass valve control device 10 is turned off in step 107, and then in step 108.
Proceed to. Therefore, the bypass valve 9 is closed, the bypass 8 is closed, and all the supercharged air compressed by the exhaust turbine supercharger 4 and the mechanically driven supercharger 5 is sent to the engine 1 side. Conversely, when the intake manifold 15 internal pressure P1 is higher than the predetermined pressure Po (P1>Po), the process proceeds to step 106, where the bypass valve control device 10 is turned on, the bypass valve 9 is opened, and the bypass 8 is closed. communicate. Therefore,
In this case, a part of the supercharging pressure (supercharging pressure) sent out from the outlet of the mechanically driven supercharger 5 is returned to the inlet of the mechanically driven supercharger 5 via the bypass 8.

In this way, the pressure inside the intake manifold
By controlling the opening and closing of the bypass valve 9 according to P1, the intake manifold 15 internal pressure P1 is maintained at a predetermined pressure Po.

On the other hand, the throttle valve upstream pressure P2 near the throttle valve 7 is introduced into the wastegate actuator 19, and when this pressure exceeds a predetermined value, the exhaust gas is released through the wastegate 18, and the exhaust gas is released from the exhaust turbine 4a.
At the same time, the overspeed of the throttle valve is suppressed, and the supercharging pressure by the compressor 4b is adjusted, and the throttle valve upstream pressure P2 becomes a predetermined value Po' after receiving the intake resistance from the mechanically driven supercharger 5, intercooler 6, etc. controlled in a similar manner.

Next, in step 102, when the engine speed exceeds the supercharger cutoff speed Ne ₀ (Ne
>Ne ₀ ), the control unit 14 controls the electromagnetic clutch 1
1 is turned off (step 103) to stop driving the mechanically driven supercharger 5, and in step 106, the bypass valve control device 10 is activated to fully open the bypass valve 9. In this case, only the exhaust turbine supercharger 4 is operated independently, and supercharging air sent from the compressor 4b of the exhaust turbine supercharger 4 passes through the bypass 8 to the intercooler 6, It is sent to the throttle valve 7 side.

In this way, the operation of the mechanically driven supercharger is stopped,
When the exhaust turbine type supercharger shifts to independent operation, if no consideration is given, the supercharging pressure will temporarily decrease by the amount that the supercharging effect of the mechanically driven supercharger 5 is lost. However, in this embodiment, the pressure P2 upstream of the throttle valve near the throttle valve 7 is introduced into the wastegate actuator 19, and the wastegate 18 is instantly activated by the amount of supercharging pressure of the mechanically driven supercharger.
In this way, the exhaust turbine 4
The exhaust flow rate to the a side is increased to increase the turbine output, thereby preventing a drop in supercharging pressure, and the supercharging pressure supplied to the engine 1 to be kept constant.

Furthermore, when the exhaust turbine supercharger 4 continues to operate independently, the bypass 8 is in the open mode, so when both the exhaust turbine supercharger 4 and the mechanically driven supercharger 5 are operated, the bypass 8 is in the open mode. Bypass valve like 9
Instead of opening/closing control, the wastegate actuator 19 uses the throttle valve upstream supercharging pressure P2 taken in via the detection tube 13b to set P2 to the set supercharging pressure.
The valve opening force of the waste gate 18 is adjusted so that P ₀ '.

According to this embodiment, depending on the operating state of the engine,
By selectively operating the exhaust turbine type supercharger 4 and the mechanically driven supercharger 5, effective boost pressure control can be performed by utilizing the features of both turbochargers, and in particular, the following effects can be obtained. .

First, when both the exhaust turbine type supercharger 4 and the mechanically driven supercharger 5 are in operation, the bypass valve control device 10 detects the pressure P1 on the downstream side of the throttle valve, and
Since the supercharging pressure Po is controlled to be the set supercharging pressure Po, the supercharging pressure of the intake air supplied to the engine can be controlled with high precision. Further, in this P1 control, since the P1 detection position and the position of the bypass 8 for adjusting P1 are close, the time lag between them can be reduced and the responsiveness of the supercharging pressure control can be accelerated.

Second, when the exhaust turbine supercharger 4 is in independent operation, the wastegate actuator 10 controls the throttle valve near the throttle valve 7 instead of the bypass valve control device 10 controlling the boost pressure. upstream pressure
Since P2 is detected and controlled so that P2 becomes the set supercharging pressure Po', supercharging pressure control can be performed with accuracy close to P1 control in this case as well. Also, it is effective to reduce the drop in boost pressure to the internal combustion engine when switching from the operation mode of the exhaust turbine supercharger 4 and mechanically driven supercharger 5 to the independent operation of the exhaust turbine supercharger 4. can be prevented.

Thirdly, P2 is detected and the exhaust turbine supercharger is operated in both the exhaust turbine supercharger 4 and the mechanically driven supercharger 5, and in the single operation of the exhaust turbine supercharger 4. Since the rotation of the feeder 4 is controlled, over-rotation of the supercharger 4 is prevented and reliability of the device is guaranteed.

Fourth, the wastegate actuator 19
Only positive pressure is introduced into the working chamber 19a of
Lighten the load on the diaphragm.

FIG. 3 is a configuration diagram of a supercharging system showing a second embodiment of the present invention. In the figure, the same reference numerals as in the first embodiment described above indicate the same or common elements.

The system configuration of this embodiment is almost the same as that of the first embodiment, and here, the differences from the first embodiment will be described.

In this embodiment, a switching valve 20 and a detection tube 2 are provided in the working chamber 19a of the wastegate actuator 19.
1 and 13b, an exhaust turbine supercharger 4
The outlet pressure P3 of the compressor 4b and the throttle valve upstream pressure P2 near the throttle valve 7 are set to be selectively introduced. That is, the detection tube 21 serves as a means for detecting P3, and the detection tube 13b serves as a means for detecting P2.

The switching valve 20 is switched and controlled by the control unit 14. When the rotational speed Ne of the internal combustion engine 1 is less than or equal to a predetermined supercharger cutoff rotational speed _Ne0 , the control unit 14 switches the switching valve 20 to the detection pipe 21.
Switch to the side, wastegate actuator 1
9 is the outlet pressure P3 of the exhaust turbine compressor 4b.
is introduced, and when the rotational speed Ne is Ne ₀ or more, the switching valve 20 is switched to the detection tube 13 side, and the wastegate actuator 19 receives the pressure on the upstream side of the throttle valve 7.
I am trying to install P2.

Here, the operation of this embodiment will be explained based on the flowchart of FIG.

Step 200 is a start and is activated at regular intervals by another operation. First, in step 201, the control unit 14 compares the engine speed Ne with a preset idle speed to determine the idle state. During idle operation (Ne≦Ne idle), the electromagnetic clutch 11 is turned off in step 203, the bypass valve control device 10 is turned on in step 204, and the bypass valve 9 is turned off.
is opened, and the switching valve 20 is turned off in step 205, and the wastegate actuator 19 is
The compressor 4b outlet pressure P3 is introduced and the process proceeds to step 214. In this state, as in the first embodiment, the exhaust turbine supercharger 4 operates independently, and air corresponding to idle is supplied to the engine 1 through the bypass 8. In addition, wastegate actuator 1
9 is controlled based on the outlet pressure P3 of the compressor 4b of the exhaust turbine supercharger 4.

Next, in step 210, if the engine speed Ne is greater than the idle speed, that is, when the engine is not in an idling state, the process proceeds to step 202, where the preset supercharger cutoff speed Ne ₀ is set.
When N≦Ne ₀ , the control unit 14
Turn on the electromagnetic clutch 11 (step
209), both the exhaust turbine supercharger 4 and the mechanically driven supercharger 5 are operated. And the steps
At 210, the intake manifold 15 internal pressure P1 applied to the bypass valve control device 10 is compared with a preset pressure Po. When P1≦Po, the bypass valve control device 10 is turned off in step 212, the bypass valve 9 is closed, and all the supercharged air compressed by the exhaust turbine supercharger 4 and the mechanically driven supercharger 5 is It is sent to the intake manifold 15 side. Conversely, when P1>Po, the bypass valve control device 10 is turned on in step 211, the bypass valve 9 is opened, the bypass 8 is communicated, and a portion of the supercharged air sent out from the outlet of the mechanically driven supercharger 5 is turned on. is returned via a bypass 8 to the inlet of the mechanically driven supercharger 5. In this way, the bypass valve 9 is controlled to open and close according to the intake manifold internal pressure P1,
The pressure inside the intake manifold 15 is kept constant. In addition, in such an operating range, the switching valve 20 is turned off, and the outlet pressure P3 of the exhaust turbine type compressor 4b is introduced into the wastegate actuator 19 via the detection tube 21, and this compression When the outlet pressure P3 of the compressor 4b exceeds the predetermined value Po', the exhaust gas is released through the waste gate 18 to suppress the rotation speed of the turbine 4a, and the supercharging pressure of the compressor 4 is adjusted. Prevents over-rotation.

Next, when the engine speed exceeds a predetermined speed Ne ₀ (Ne>Ne ₀ ), the control unit 14 turns off the electromagnetic clutch 11 (step 206) and stops the operation of the mechanically driven supercharger 5. Then, the bypass valve control device 10 is turned on to fully open the bypass valve 9. In this case, supercharged air compressed by the independently operated exhaust turbine supercharger 4 is supplied to the engine 1 through the bypass 8, the intercooler 6, the throttle valve 7, and the like. Also, at this time, the control unit 14 turns on the switching valve 20, and the supercharging pressure P2 in the upstream 7a near the throttle valve 7 is introduced to the wastegate actuator 19 as a control pressure via the detection tube 13b.

The control pressure introduced from the upstream side of the throttle valve 7 weakens the opening force of the wastegate 18 via the wastegate actuator 19 by the amount that the supercharging pressure of the mechanically driven supercharger 5 disappears. As in the first embodiment, the turbine output is increased to prevent the supercharging pressure from dropping. Furthermore, when the exhaust turbine supercharger 5 continues to operate independently, the upstream supercharging pressure P2 near the throttle valve replaces the supercharging pressure P1 downstream of the throttle valve, so that P2 becomes the target supercharging pressure Po'. The wastegate actuator 19 controls the boost pressure.

According to this embodiment, in addition to highly accurate supercharging pressure control as in the first embodiment, when both the exhaust turbine type supercharger and the mechanically driven supercharger are operated, the waste gate actuator Since the outlet pressure P3 of the exhaust turbine compressor 4b is introduced into the exhaust turbine 19 to adjust the opening of the waste gate 18, over-rotation of the exhaust turbine supercharger can be prevented even more reliably.

5 to 7 are configuration diagrams of other modified supercharging systems related to the present invention.
In the figure, the same reference numerals as those in the first embodiment already described are
It indicates the same or common element.

In the example shown in FIGS. 5 and 6, the mechanically driven supercharger 5 is connected not only to the wastegate actuator 19 of the exhaust turbine supercharger 4 but also to the bypass valve control device 10 via a communication pipe 13a'. downstream of the throttle valve 7
The nearby throttle valve upstream pressure P2 was introduced. According to this method, the steps shown in Fig.
The supercharging pressure compared with the set pressure Po at 105 is the upstream pressure P2 immediately near the throttle valve 7, and the bypass valve 9 is controlled to open and close based on this control pressure, and the accuracy is the same as that of the first and second embodiments. However, it is still possible to obtain better supercharging pressure control than the conventional system in which the engine-supplied supercharging pressure is controlled using the compressor outlet pressure of an exhaust turbine supercharger.

In the example shown in FIG. 7, the control pressure introduced into the wastegate actuator 19 and the bypass valve control device 10 is introduced from the downstream side of the throttle valve 7, but the pressure on the downstream side of the throttle valve 7 is It is introduced into the motor 19 when the supercharger cut-off rotation speed Ne is ₀ or more (in this case, the opening degree of the throttle valve 7 is large and the downstream side of the throttle valve 7 is under positive pressure), and in other cases. Since the pressure immediately downstream of the exhaust turbine type compressor 4b is introduced into the wastegate actuator 19, even in this method, only positive pressure is introduced into the wastegate actuator 19. It is possible to reduce the load on the

〔Effect of the invention〕

According to the present invention, when both the exhaust turbine type supercharger 4 and the mechanically driven supercharger 5 are operated, the pressure P1 downstream of the throttle valve, which is most ideal for controlling the boost pressure supplied to the engine, is controlled. The bypass valve control device 10 on the mechanically driven supercharger side controls the opening and closing of the bypass valve 9 upon detection, and when the exhaust turbine supercharger 5 is operating independently, the bypass valve 10 is in open mode), then the ideal throttle valve upstream pressure P2 near the throttle valve
The wastegate actuator 19 controls the boost pressure supplied to the engine by detecting the
Enables highly accurate boost pressure control.

In addition, the wastegate actuator 19 always has a pressure (positive pressure) P2 on the upstream side of the throttle valve or
P3 is introduced to detect these pressures, thereby preventing the exhaust turbine supercharger 4 from overspeeding.
Furthermore, the load on the wastegate actuator can be reduced and its lifespan can be improved.

[Brief explanation of drawings]

FIG. 1 is a system configuration diagram of a first embodiment of the present invention, FIG. 2 is a flowchart for explaining the operation of the first embodiment, and FIG. 3 is a system configuration diagram of a second embodiment of the present invention. FIG. 4 is a flowchart for explaining the operation of the second embodiment, and FIGS. 5 to 7 are system configuration diagrams of other modified examples illustrated in relation to the present invention. 1... Internal combustion engine, 2... Intake passage, 3... Exhaust passage, 4... Exhaust turbine supercharger, 5... Mechanically driven supercharger, 7... Throttle valve, 8... Relief valve.
Bypass and passage, 9...Bypass valve, 10...Bypass valve control device, 17...Exhaust bypass, 18
...Wastegate, 19...Wastegate actuator, 20...Switching valve.

Claims (1)

[Claims] 1. An exhaust turbine supercharger 4 and a mechanically driven supercharger 5 located downstream thereof in the intake passage 2 of an internal combustion engine.
When supercharging is required and the engine speed Ne is less than a predetermined value Ne ₀ , the exhaust turbine supercharger 4
and the mechanically driven supercharger 5 are both operated for supercharging,
This supercharging device stops the supercharging operation of the mechanically driven supercharger 5 and switches to the supercharging operation of the exhaust turbine supercharger 4 alone when the engine speed Ne becomes Ne ₀ or more. In the supercharging device, the exhaust passage 3 is provided with a bypass 17 with a waste gate 18 that allows a part of the exhaust gas to bypass the exhaust turbine 4a of the exhaust turbine type supercharger.The throttle valve 7 of the intake passage 2 is mechanically driven. The wastegate actuator 19 is arranged downstream of the mechanically driven supercharger 5, and includes means 13b for detecting the throttle valve upstream supercharging pressure P2 near the throttle valve 7 on the downstream side of the mechanically driven supercharger 5, and Mechanisms 19a and 19b that adjust the valve opening force of the waste gate 18 so that the valve upstream supercharging pressure P2 becomes the set supercharging pressure P0 _'
A bypass 8 with a valve 9 that bypasses the mechanically driven supercharger 5 is provided in the intake passage 2, and a bypass valve control device 1 that controls the opening and closing of this valve 9.
0 includes at least a means for opening the valve 9 so that the bypass 8 enters the bypass mode during independent supercharging operation of the exhaust turbo supercharger 4, and a means 13a for detecting the supercharging pressure P1 downstream of the throttle valve 7.
and an exhaust turbo supercharger 4 and a mechanically driven supercharger 5
During both supercharging operations, when the downstream supercharging pressure P1 of the throttle valve becomes less than the set value _P0 , the valve 9 is closed, and when it becomes more than the set value _P0 , the valve 9 is opened, and the throttle is set to the set value Po as the target value. It consists of a means for controlling the boost pressure P1 downstream of the valve, and when the valve 9 is opened in the throttle valve downstream boost pressure P1 control (that is, when P1 becomes equal to or higher than Po and the valve 9 opens). , a bypass 8 transfers a portion of the supercharging air downstream of the mechanically driven supercharger 5 to the mechanically driven supercharger 5.
A supercharging device for an internal combustion engine, characterized in that it is configured to also serve as a relief passage for returning upstream. 2 In claim 1, the wastegate actuator 19 is a mechanically driven supercharger 5.
Throttle valve upstream supercharging pressure P2 near throttle valve 7 on the downstream side of
In addition to the means 13b for detecting, means 21 for detecting supercharging pressure P3 near the compressor outlet of the exhaust turbine supercharger 4 between the exhaust turbine supercharger 4 and the mechanically driven supercharger 5; The supercharging pressure P2 to be detected,
It has a switching means 20 that selectively takes in P3, and the switching control of this switching means 20 causes the wastegate actuator 19 to control the throttle valve upstream supercharging pressure P2 during independent supercharging operation of the exhaust turbine supercharger 4. is taken in to adjust the valve opening force of the waste gate 18, and the supercharging pressure P3 at the outlet side of the exhaust turbine supercharger is adjusted during supercharging operation of both the exhaust turbine supercharger 4 and the mechanically driven supercharger 5. A supercharging device for an internal combustion engine that makes it possible to adjust the valve opening force of the waste gate 18 by taking in the valve opening force.