JPH0523783Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention is an internal combustion engine supercharger that uses a combination of a mechanical supercharger driven by engine output and a turbo supercharger driven by exhaust energy. Regarding the feeding device.

Conventional technology Unlike turbochargers, mechanical superchargers that use roots blowers have the advantage of providing supercharging effects even in low speed ranges, but they produce large noise and mechanical losses in high speed ranges. There is a drawback. Therefore,
Conventionally, a supercharging device that combines a mechanical supercharger suitable for a low speed range and a turbo supercharger suitable for a high speed range has been disclosed in, for example, Japanese Utility Model Application Publication No. 60-26235. In this system, a mechanical supercharger is installed downstream of the compressor of the turbo supercharger, and a control valve is installed in a bypass passage that bypasses the mechanical supercharger to open and close the passage. The machine's drive mechanism includes an electromagnetic clutch. In a low load region where the throttle opening is less than the set opening, the electromagnetic clutch is disengaged to prevent the mechanical supercharger from operating, and the control valve is fully opened to allow intake air to directly flow into the engine. . Further, when the throttle opening reaches an acceleration state exceeding the set opening, the control valve is closed and the electromagnetic clutch is engaged to start supercharging by the mechanical supercharger. As a result of acceleration, when the rotational speed of the turbocharger increases and the intake pressure downstream of the compressor, that is, upstream of the mechanical supercharger, exceeds a predetermined pressure, the electromagnetic clutch is disengaged again, and the mechanical supercharger At the same time, the control valve is fully opened to allow intake air from the turbocharger to flow directly into the engine. In addition, the opening degree of the above control valve is
When the mechanical supercharger starts operating, it is fully closed, and then gradually opens as the intake pressure downstream of the mechanical supercharger increases, keeping the intake pressure downstream of the mechanical supercharger constant. I'm learning to keep it.

Problems to be solved by the invention In the above conventional supercharging device, as mentioned above, in the low load region where the mechanical supercharger is not operating,
The control valve is always kept fully open, and then controlled to be fully closed when an acceleration state is detected.

Therefore, when the electromagnetic clutch engages and the mechanical supercharger starts operating in the acceleration state, there is a slight response delay before the control valve changes from fully open to fully closed, and during that time the supercharging This means that the pressure will not increase. As a result, it had the disadvantage of poor acceleration performance.

Means for Solving the Problems In order to solve the above problems, the supercharging device for an internal combustion engine according to the present invention includes a turbo supercharger and a machine driven by the engine output via an electromagnetic clutch. In a supercharging system for an internal combustion engine, which is equipped with a mechanical supercharger and a control valve that opens and closes a bypass passage that bypasses the mechanical supercharger, a predetermined amount of energy is charged based on engine operating conditions and the operating state of the turbo supercharger. a clutch control means for switching the electromagnetic clutch to the connection side during acceleration; and a first clutch control means for driving the control valve to a fully closed state when switching the electromagnetic clutch to the connection side.
a second control valve control means for correcting the opening degree of the control valve according to the boost pressure during operation of the mechanical supercharger; and third control valve control means for maintaining the control valve in a predetermined half-open state when the control valve is controlled to be in a predetermined half-open state.

Operation: In a low load region where the mechanical supercharger is not operating, that is, in a state where the electromagnetic clutch is disconnected, the control valve is held in a predetermined half-open state by the third control valve control means. When the engine accelerates from this state, the electromagnetic clutch is switched to the connected side by the clutch control means, and the mechanical supercharger starts operating. At the same time, the first control valve control means drives the control valve to a fully closed state. At this time, since the control valve is already waiting in a half-open state, it quickly becomes fully closed without any response delay, and the supercharging pressure immediately increases. Note that, thereafter, the opening degree of the control valve is corrected by the second control valve control means according to the boost pressure.

Example Figure 1 shows an example of this invention.
is an internal combustion engine, 2 is a turbo supercharger, and 3 is a mechanical supercharger consisting of a roots blower and the like.

The turbo supercharger is generally composed of a turbine 5 installed in the exhaust passage 4 of the internal combustion engine 1, and a compressor 6 driven by the turbine 5 and installed in the intake passage 7. An air cleaner 8 and an air flow meter are disposed upstream of the compressor 6, and an air cleaner 8 and an air flow meter are disposed upstream of the compressor 6.
A downstream intake passage 7 is connected to an intake manifold 10 . Note that a waste gate passage 11 is formed in the exhaust passage 4, bypassing the turbine 5, and a waste gate valve 12 that opens by pressure on the outlet side of the compressor 6 is disposed therein.

On the other hand, a mechanical supercharger 3 consisting of a Roots blower, etc.
is interposed between the compressor 6 of the turbocharger 2 and the intake manifold 10, and its drive shaft is connected to the internal combustion engine via an electromagnetic clutch 14 and a belt 15, which are controlled intermittently by a control unit 13. 1 output shaft 16. A bypass passage 17 that bypasses the mechanical supercharger 1 is formed in the intake passage 7,
A butterfly valve type control valve 18 is disposed here. 19 is a step motor that drives the control valve 18. Reference numeral 20 indicates a throttle valve disposed downstream of the mechanical supercharger 3, and 21 indicates a throttle opening sensor for detecting the opening of the throttle valve 20.

Further, in the intake passage 7 between the compressor 6 of the turbocharger 2 and the mechanical supercharger 3, a first pressure sensor 22 is arranged to detect the intake pressure P _A upstream of the mechanical supercharger 3. A second pressure sensor 23 is disposed in the intake passage 7 between the mechanical supercharger 3 and the throttle valve 20 to detect the intake pressure P _B upstream of the throttle valve 20.

The control unit 13 that controls the electromagnetic clutch 14 and the control valve 18 is composed of a so-called microcomputer system, and includes an MPU 24,
It is configured to include a ROM 25, a RAM 26, an input port 27, an output port 28, and the like. A throttle opening sensor 21 and first and second pressure sensors 22 and 23 are connected to the input port 27, and an electromagnetic clutch 14 and a step motor 19 are connected to the output port 28.

FIG. 2 is a flowchart showing the details of the control executed by the control unit 13, which will be explained below.

First, in step 1, the throttle opening sensor 2
Throttle opening based on the output signal of 1
Read THROT and compare it with the set opening THROTA in step 2. This setting opening
If it is in the low load range below THROTA, proceed to steps 3 and 4, set flags 1 and 2 to "0", and close the electromagnetic clutch 14 in step 5.
Turn it OFF. Therefore, in this case, the mechanical supercharger 3 does not operate. and step 6 flag 2
After the determination, the process proceeds to step 7, where the control valve 18
The opening degree K is set to a predetermined half-open state Kset. This control valve opening degree Kset is the intake pressure downstream of the control valve 18.
P _B is preset to such an extent that it does not become a negative pressure.
Note that this opening degree Kset may be a fixed value A as shown in FIG. 3, but it may also be set to be variable as shown by a solid line B in accordance with the engine intake air amount.

Next, in step 9, the intake pressure _P A upstream of the mechanical supercharger 3 is read based on the detection signal of the first pressure sensor 22, and in step 10, this is set to the set value.
Compare with P _MaX . When the set value P _MaX or higher, that is, in the region where the turbo supercharger 2 is fully operating,
The flag 2 is set to "1" (step 11), and the mechanical supercharger 3 is stopped (step 5). and,
In this case, the process proceeds to step 8 after determining flag 2 in step 6, where the opening degree K of the control valve 18 is maximized. Therefore, in this case, the control valve 18 is fully open, and the intake air from the turbocharger 2 flows directly into the engine through the bypass passage 17.

During acceleration, that is, the throttle opening THROT is greater than the set opening THROTA, and the intake pressure P _A is the set value.
If it is less than P _MaX , the process advances to step 12 and the electromagnetic clutch 14 is engaged. As a result, mechanical supercharger 3
is activated. Then, flag 1 is determined in step 13, and since flag 1 is 0 in step 3 for the first time after acceleration, the process proceeds from step 13 to step 14, and sets the opening degree K of the control valve 18 to 0, that is, fully closed. shall be. Next, in step 15, set flag 1 to "1"
shall be. Therefore, the entire amount of intake air is guided to the mechanical supercharger 3, and supercharging starts. However, since the control valve 18 is already in the half-open state as described above, the control valve 18 is The fully closed state is achieved without any response delay, and supercharging immediately begins.

On the other hand, next time, proceed from step 13 to step 16. In step 16, the pressure downstream of mechanical supercharger 3 is
P _B is read based on the detection signal of the second pressure sensor 23, and in step 17, the opening degree K of the control valve 18 is corrected so as to maintain this intake pressure P _B at a predetermined pressure.

FIG. 4 shows, as an example, changes in the intake pressures P _A and P _B and changes in the opening of the control valve 18 that occur during acceleration. Since the delay in the closing operation of the control valve 18 compared to operation A is very small, the intake pressure P _B rises quickly and excellent acceleration performance is obtained.

Effects of the invention As is clear from the above explanation, in the supercharging system for an internal combustion engine according to this invention, when the mechanical supercharger is stopped in a low load region, the control valve is kept in a predetermined half-open state. Since this is maintained, when the engine accelerates thereafter, the control valve can be fully closed immediately, and the supercharging pressure can be quickly increased.
This provides excellent acceleration performance with no response delay.

[Brief explanation of drawings]

Fig. 1 is a configuration explanatory diagram showing an embodiment of this invention, Fig. 2 is a flowchart showing a control program of this embodiment, and Fig. 3 shows the relationship between the half-opening degree of the control valve and the intake air flow rate. The characteristic diagram, FIG. 4, is a time chart showing pressure changes in various parts during acceleration. 1... Internal combustion engine, 2... Turbo supercharger, 3...
Mechanical supercharger, 13...control unit,
14... Electromagnetic clutch, 17... Bypass passage,
18...Control valve.

Claims (1)

[Claims for Utility Model Registration] A turbo supercharger, a mechanical supercharger driven by engine output via an electromagnetic clutch, and a control valve that opens and closes a bypass passage that bypasses the mechanical supercharger. A supercharging device for an internal combustion engine, comprising: a clutch control means for controlling the electromagnetic clutch to be switched to the connection side at a predetermined acceleration based on engine operating conditions and the operating state of the turbocharger; and a connection of the electromagnetic clutch. a first control valve control means that drives the control valve to a fully closed state when switching to the side, and a second control valve control means that corrects the opening degree of the control valve according to the boost pressure during operation of the mechanical supercharger. and third control valve control means for maintaining the control valve in a predetermined half-open state when the electromagnetic clutch is controlled to be in the disengaged state in a low engine load region. A supercharging device for internal combustion engines.