JPH10299524A - Intake device for engine with mechanical supercharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve reliability and durability of a mechanical supercharger and improve fuel consumption performance and acceleration response of an engine, in an engine with mechanical supercharger. SOLUTION: In a bypass passage 30 connected to bypass a location of the upstream/downstream of a mechanical supercharger 5 provided in an intake passage 2, an opening/closing valve 31 is provided, this opening/closing valve 31 is opened in a low load region and closed in a high load region, also a drive region of the supercharger 5 is set to at least one part region of a high/low load region. In an upstream location from a branch part in the upstream of the bypass passage 30, an upstream throttle part 10, in a downstream location from a confluent part in the downstream, a downstream throttle part 20 are respectively provided, by these upstream/downstream throttle parts 10, 20, a suction intake air amount is adjusted, on the other hand, in a relation of an opening area of both the throttle parts 10, 20 in the drive region of the supercharger 5, so as to increase the opening area of the downstream throttle part 20 in an opening region of the opening/closing valve 31 and the opening area of the upstream throttle part 10 in a closing region of the opening/closing valve 31, at least one opening area of both the throttle parts 10, 20 is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake device for an engine having a mechanical supercharger.

[0002]

2. Description of the Related Art As one of the supercharging methods in an automobile engine, it is known to provide a mechanical supercharger driven by an engine (for example, Japanese Utility Model Publication No. 3-1578).
No. 4). In this known example, while a mechanical supercharger driven by an engine via a clutch is provided in an intake passage, a bypass passage bypassing the mechanical supercharger is provided, and the bypass passage is provided in the bypass passage. Is provided with a control valve for opening and closing the passage. Then, the clutch is connected to the engine according to the engine speed and the engine load, specifically, when the rotational speed is equal to or higher than a predetermined rotational speed, and when the load is equal to or higher than a predetermined load, the clutch is connected to the mechanical supercharger. In addition to driving the clutch, the control valve is opened while the clutch is connected in a region where the clutch speed is equal to or higher than a predetermined rotation speed and equal to or lower than a predetermined load. While improving,
The drive loss associated with the drive of the mechanical supercharger in the low-load, high-speed region, which is a region where supercharging is unnecessary, is reduced.

[0003]

However, when the mechanical supercharger is driven by opening the bypass passage in the low engine load region, the mechanical supercharger does not actually perform the supercharging work. Although the drive loss of the turbocharger can be reduced, since the blower work for moving the air on the upstream side of the mechanical supercharger to the downstream side is performed, the rotational speed of the mechanical supercharger in particular increases. In the high engine speed range, the amount of air movement per hour increases, and the drive loss of the mechanical supercharger due to the movement of air is not negligible in terms of engine fuel efficiency.

By the way, in the above-mentioned known example,
A throttle valve is disposed downstream of the mechanical supercharger and downstream of the junction of the bypass passage, and the intake amount is adjusted by the throttle valve. However, when the throttle valve is arranged on the downstream side of the mechanical supercharger in this way, the air in the atmospheric pressure state having a relatively high air density is moved from the upstream side to the downstream side by the mechanical supercharger. Therefore, the drive loss of the mechanical supercharger due to the movement of air is relatively large, and the fuel consumption performance is reduced accordingly. In this known example,
Although a blow-type roots pump is used as the mechanical supercharger, instead of this, if the mechanical supercharger is an internal compression pump such as a Rischholm pump, the mechanical supercharger itself is used. Due to the presence of the internal compression section, the drive loss of the mechanical supercharger is further increased, and the fuel efficiency cannot be overlooked.

Accordingly, the present invention is to improve the reliability and durability of a mechanical supercharger by optimizing the method of adjusting the intake air amount according to the operating state of the engine in a mechanical supercharged engine. The purpose is to improve the fuel efficiency and acceleration response of the engine.

[0006]

Means for Solving the Problems In the present invention, the following configuration is adopted as specific means for solving such problems.

In the first invention of the present application, a mechanical supercharger provided in an intake passage and driven via an output shaft of an engine, and an upstream portion and a downstream portion of the supercharger in the intake passage are provided. A bypass passage that bypasses and connects the turbocharger; and an on-off valve that controls opening and closing of the bypass passage in accordance with an operation state of the engine. In the intake system of the engine with the mechanical supercharger, the valve is closed in the region and the drive region of the supercharger is set in at least a part of the high engine load region and the low engine load region. An upstream throttle portion that changes an opening area of an intake passage at an upstream portion of the bypass passage at a position upstream of a branch portion of the bypass passage on the upstream side of the supercharger in a passage, and a downstream side of the supercharger in the intake passage. Downstream throttle portions that change the opening area of the intake passage at the downstream portion are provided at a portion downstream of the junction of the bypass passage, and the upstream throttle portion and the downstream throttle portion reduce the amount of intake air taken into the engine. On the other hand, the relationship between the opening areas of the two throttle portions in the drive region of the turbocharger, the opening area of the upstream throttle portion is larger than the opening area of the downstream throttle portion in the valve opening region of the on-off valve. Small, in the valve closing region of the on-off valve, at least one of the upstream throttle portion and the downstream throttle portion so that the opening area of the upstream throttle portion is larger than the opening area of the downstream throttle portion. It is characterized in that the opening area is controlled.

According to a second aspect of the present invention, in the intake device for a mechanically-charged engine according to the first aspect, the opening degree of the on-off valve gradually closing from full open with an increase in engine load. While having characteristics, the relationship between the opening area of the upstream throttle section and the downstream throttle section is such that the opening area of the upstream throttle section is smaller than the opening area of the downstream throttle section when the on-off valve is fully open. It is set so that when the acceleration state of the engine is detected, the opening area of the upstream throttle portion is greater than or equal to the opening area of the downstream throttle portion with the start of the valve closing operation from the full opening of the on-off valve. The opening area of at least the upstream throttle portion of the two throttle portions is controlled so that the opening area is controlled.

According to a third aspect of the present invention, in the intake system for a mechanical supercharged engine according to the first aspect, the opening degree of the on-off valve gradually closing from full open with an increase in engine load. With the characteristic, the relationship between the opening area of the upstream throttle section and the opening area of the downstream throttle section is smaller than the opening area of the upstream throttle section when the on-off valve is fully opened. When the deceleration state of the engine is detected in the drive region of the supercharger, the opening area of the upstream throttle portion is reduced until the opening of the on-off valve opens at least to the partial opening state. The opening area of at least the upstream throttle section of the two throttle sections is controlled so as to be equal to or larger than the opening area of the downstream throttle section.

According to a fourth aspect of the present invention, in the intake device for a mechanical supercharged engine according to the first aspect, no clutch means is provided so that the supercharger is always driven by an engine output shaft. A drive transmission means is provided, and the on-off valve is opened in the entire low-load region of the engine, and the opening area of the upstream throttle portion is larger than the opening area of the downstream throttle portion in the opening region of the on-off valve. The opening area of at least one of the upstream throttle portion and the downstream throttle portion is controlled so as to be small.

According to a fifth aspect of the present invention, in the intake device for a mechanical supercharged engine according to the first aspect, a clutch means for stopping the driving of the supercharger in a low engine load / low speed range is provided. When the drive of the supercharger is stopped, the on-off valve is opened, and at least the upstream portion of the two throttle portions is so arranged that the opening area of the upstream throttle portion is larger than the opening area of the downstream throttle portion. The opening area of the side stop portion is controlled.

According to a sixth aspect of the present invention, in the intake system for a mechanical supercharged engine according to the first aspect, the downstream throttle portion is constituted by an electrically operated downstream throttle valve. The required throttle air amount of the engine is controlled by the downstream throttle valve, and the upstream throttle portion is constituted by an upstream throttle valve that is mechanically connected to an accelerator that is manually operated and that operates in conjunction with the accelerator. In addition, the opening amount characteristic of the upstream throttle valve, in the increasing direction of the accelerator opening, when the accelerator opening is low, the opening area of the upstream throttle section is smaller than the opening area of the downstream throttle section. The opening rate increase rate is small so that the opening area of the upstream throttle section is larger than the opening area of the downstream throttle section at least at the time of the accelerator high opening degree at the middle opening degree. It is characterized in that there is a non-linear characteristic that.

According to a seventh aspect of the present invention, in the intake system for a mechanical supercharged engine according to the second aspect, the required intake air amount of the engine is controlled based on an accelerator operation in the downstream throttle portion. A main throttle valve is provided, and when the on-off valve is fully open, the intake air amount is metered by the upstream throttle section, and when an acceleration state of the engine is detected, the opening area of the upstream throttle section is increased. It is characterized in that it is controlled to be larger than the opening area of the downstream throttle section.

According to an eighth aspect of the present invention, in the intake device for a mechanically-charged engine according to the third aspect, the upstream throttle portion includes a plate-shaped throttle valve and a bypass valve that bypasses the throttle valve. And an upstream throttle valve bypass passage connecting the upstream and downstream sides thereof, and an electromagnetic upstream flow control valve is provided in the upstream throttle valve bypass passage, and the on-off valve is at least partially opened. The opening area of the upstream throttle section is made larger than the opening area of the downstream throttle section by the upstream flow rate control valve until the valve opens at every time, and after the opening and closing valve has at least a partial opening degree, The opening area of the upstream throttle portion is controlled such that the opening area of the upstream flow rate control valve is reduced so that the opening area of the upstream throttle portion is smaller than the opening area of the downstream throttle portion. I have.

According to a ninth aspect of the present invention, in the intake apparatus for an engine with a mechanical supercharger according to the first aspect, the supercharger is stopped in a low engine load / low speed range. In the low-load / high-speed range, a clutch means for driving is provided. On the other hand, the on-off valve is opened in the entire low-load region of the engine. The opening area of the upstream throttle section is larger than the opening area of the downstream throttle section in the drive stop area of the charger, and the opening area of the upstream throttle section is larger than the opening area of the downstream throttle section in the drive area of the supercharger. The opening area of at least one of the upstream throttle section and the downstream throttle section is controlled so as to be smaller than the opening area.

In the tenth aspect of the present invention, the second and fourth aspects are
Alternatively, in the intake device for a mechanical supercharged engine according to the fifth invention, the upstream throttle portion is provided with the upstream throttle valve, and the downstream throttle portion is provided with the downstream throttle valve. While the upstream throttle valve and the downstream throttle valve are connected to an accelerator which is mechanically operated manually, the upstream throttle valve side is connected to the upstream side and the downstream side bypassing the upstream throttle valve. An upstream throttle valve bypass passage is provided, and the upstream throttle valve bypass passage is provided with an electromagnetic upstream flow control valve for adjusting the opening amount of the passage, and by controlling the upstream flow control valve. The relationship between the opening areas of the two throttle portions, the relationship that the opening area of the upstream throttle portion is smaller than the opening area of the downstream throttle portion, and the opening area of the upstream throttle portion is smaller than the opening area of the downstream throttle portion. Less relation that becomes larger than opening area It is characterized in that also was adapted to set either.

According to an eleventh aspect of the present invention, in the intake system for a mechanically-charged engine according to the tenth aspect, the downstream throttle valve bypasses the downstream throttle valve and upstream of the downstream throttle valve. And a downstream throttle valve bypass passage connecting the downstream side and a downstream flow control valve for adjusting the opening amount of the downstream throttle valve bypass passage,
By controlling the downstream-side flow control valve in cooperation with the upstream-side flow control valve provided in the upstream-side throttle valve bypass passage, the relationship between the opening areas of the two throttle sections can be adjusted. The relationship can be set to at least one of a relationship where the area is smaller than the opening area of the downstream throttle portion and a relationship where the opening area of the upstream throttle portion is larger than the opening area of the downstream throttle portion. It is characterized by:

According to a twelfth aspect of the present invention, there is provided a mechanical supercharger provided in an intake passage and driven via an output shaft of an engine, and an upstream portion and a downstream portion of the supercharger in the intake passage. A bypass passage that bypasses and connects the turbocharger; and an on-off valve that controls opening and closing of the bypass passage in accordance with an operating state of the engine. In the intake device of the engine with the mechanical supercharger, the valve is closed in the region and the drive region of the supercharger is set in at least a part of the high engine load region and the low engine load region. An upstream throttle portion that changes the opening area of the intake passage at the upstream portion of the passage upstream of the branch portion of the bypass passage on the upstream side of the supercharger is provided downstream of the supercharger in the intake passage. A downstream throttle portion for changing the opening area of the intake passage at the downstream portion is provided at a portion downstream of the junction of the bypass passage, and the amount of intake air taken into the engine at the upstream throttle portion and the downstream throttle portion. On the other hand, the turbocharger is stopped in the low engine speed range of the low load range, the supercharger is driven in the high engine speed range, and the on-off valve is opened in the entire low engine load range. The opening area of the upstream throttle section is larger than the opening area of the downstream throttle section when the drive of the supercharger is stopped, and when the supercharger is driven, The opening area of at least one of the upstream throttle section and the downstream throttle section is controlled so that the opening area of the upstream throttle section is smaller than the opening area of the downstream throttle section. .

According to a thirteenth aspect of the present invention, in the intake device for an engine with a mechanical supercharger according to the twelfth aspect, an opening area of the downstream throttle portion is set such that an opening area of the downstream throttle portion is higher than that of the engine at a higher engine speed. On the other hand, when the supercharger is accelerated from the drive stop state to the drive state in the low load range of the engine, the turbocharger is temporarily synchronized with the operation change from the drive stop state to the drive state. It is characterized in that the opening area of the downstream throttle portion is increased.

According to a fourteenth aspect of the present invention, in the intake device for an engine with a mechanical supercharger according to the thirteenth aspect, the required amount of intake air of the engine is stored in the downstream throttle portion based on an accelerator operation. A main throttle valve to control,
A downstream throttle valve bypass passage that bypasses the main throttle valve and connects the upstream side and the downstream side thereof; and a downstream flow control valve that adjusts the opening amount of the downstream throttle valve bypass passage, respectively. The downstream flow rate control valve temporarily increases the opening area of the downstream throttle portion.

According to a fifteenth aspect of the present invention, in the intake device for a mechanical supercharged engine according to the twelfth aspect, an upstream throttle valve is provided in the upstream throttle portion, and an upstream throttle valve is provided in the downstream throttle portion. A downstream throttle valve is provided, respectively, and the upstream throttle valve and the downstream throttle valve are connected to an accelerator which is mechanically operated manually, while the upstream throttle valve bypasses the upstream throttle valve. An upstream throttle valve bypass passage connecting the upstream side and the downstream side thereof, and an electromagnetic upstream flow control valve for adjusting the opening amount of the passage is provided in the upstream throttle valve bypass passage. By controlling the upstream flow rate control valve, the relationship between the opening area of the two throttle portions, the relationship that the opening area of the upstream throttle portion is smaller than the opening area of the downstream throttle portion, and the upstream throttle portion Opening area of the downstream throttle section It is characterized in that it has adapted to set at least one of greater relation than the mouth area.

According to a sixteenth aspect of the present invention, in the intake device for a mechanically-charged engine according to the fifteenth aspect, the downstream throttle valve bypasses the downstream throttle valve and upstream of the downstream throttle valve. And a downstream throttle valve bypass passage connecting the downstream side and a downstream flow control valve for adjusting the opening amount of the downstream throttle valve bypass passage,
By controlling the downstream-side flow control valve in cooperation with the upstream-side flow control valve provided in the upstream-side throttle valve bypass passage, the relationship between the opening areas of the two throttle sections can be adjusted. The relationship can be set to at least one of a relationship where the area is smaller than the opening area of the downstream throttle portion and a relationship where the opening area of the upstream throttle portion is larger than the opening area of the downstream throttle portion. It is characterized by:

[0023]

According to the present invention, the following effects can be obtained by adopting such a configuration.

(A) An intake device for an engine with a mechanical supercharger according to the first invention of the present application is a mechanical supercharger provided in an intake passage and driven via an output shaft of the engine. A bypass passage connecting an upstream portion and a downstream portion of the supercharger in the intake passage so as to bypass the turbocharger,
An opening / closing valve for controlling the opening and closing of the bypass passage in accordance with an operation state of the engine; opening and closing the opening / closing valve in a low load region of the engine and closing the valve in a high load region; In the intake device of the engine with a mechanical supercharger, which is set in at least a part of the high engine load region and the low engine load region, the bypass passage on the upstream side of the supercharger in the intake passage An upstream throttle portion that changes the opening area of the intake passage at the upstream portion is provided at an upstream portion of the branch portion, and the upstream throttle portion is provided at a downstream portion of the junction of the bypass passage downstream of the supercharger in the intake passage. A downstream throttle portion for changing the opening area of the intake passage of each portion is provided, and while the upstream throttle portion and the downstream throttle portion adjust the intake air intake to the engine, the drive region of the supercharger is controlled. In the opening area of the on-off valve, the opening area of the upstream-side throttle section is smaller than the opening area of the downstream-side throttle section. The opening area of at least one of the upstream throttle section and the downstream throttle section is controlled so that the opening area of the side throttle section is larger than the opening area of the downstream throttle section.

Therefore, according to the present invention, in a low load region where supercharging is not required in the drive region of the mechanical supercharger, the on-off valve is opened and the upstream side of the mechanical supercharger is opened. The downstream side is connected and the differential pressure between the upstream side and the downstream side of the mechanical supercharger is reduced, and at the same time, the upstream intake passage of the mechanical supercharger is It is throttled to reduce the absolute pressure downstream of the upstream throttle. As a result, first, since the differential pressure before and after the mechanical supercharger is reduced, the sealing property of the mechanical supercharger is maintained well, and the rise in the internal temperature is suppressed, so that the mechanical supercharger is prevented from rising. The reliability or durability of the turbocharger itself is improved, and the magnitude of the differential pressure before and after the mechanical supercharger corresponds to the amount of work. The drive loss of the turbocharger is reduced, and the fuel efficiency of the engine is improved. Further, since the decrease in the absolute pressure on the upstream side of the mechanical supercharger corresponds to the decrease in the air density, the blower work of the mechanical supercharger is reduced by the decrease in the absolute pressure (in other words, The driving loss of the mechanical supercharger is reduced), and the fuel efficiency of the engine is improved accordingly.

In a high load region where supercharging is required, the differential pressure between the upstream side and the downstream side of the mechanical supercharger tends to increase by closing the on-off valve. In this case, the opening area of the upstream throttle section is set to be larger than the opening area of the downstream throttle section, so that the pressure on the upstream side of the mechanical supercharger approaches atmospheric pressure and the differential pressure increases. As a result, the reliability of the mechanical supercharger is improved, and the fuel efficiency of the engine is improved by reducing the drive loss of the mechanical supercharger.

As described above, according to the intake device for the engine with the mechanical supercharger according to the first invention, the fuel efficiency of the engine is improved while ensuring the reliability and durability of the mechanical supercharger. It is possible to achieve further improvement.

(B) In the intake device for an engine with a mechanical supercharger according to the second invention of the present application, in the intake device for an engine with a mechanical supercharger according to the first invention, the on-off valve is an engine. In addition to having an opening degree characteristic that the valve gradually closes from full open with an increase in load, the relationship between the opening area of the upstream throttle section and the downstream throttle section depends on the upstream throttle section when the on-off valve is fully open. The opening area of the upstream throttle is set so as to be smaller than the opening area of the downstream throttle section. The opening area of at least the upstream throttle section of the two throttle sections is controlled so that the opening area of the section is equal to or larger than the opening area of the downstream throttle section.

Therefore, according to the present invention, the following specific effects can be obtained in addition to the effects described in the above (a). That is, when the engine is accelerated, the on-off valve is gradually closed from the fully opened state, whereby a sudden decrease in the intake air amount is suppressed, the torque shock of the engine accompanying the closing operation of the on-off valve is prevented, and the on-off valve is fully opened. In the partial opening state in the course of reaching the fully closed state, the opening area of the upstream throttle section becomes larger than the opening area of the downstream throttle section, and the restriction on the intake amount by the upstream throttle section is released. As a result, an increase in the intake air charge is promoted, and the acceleration response of the engine is accordingly improved.

(C) In the intake device for an engine with a mechanical supercharger according to the third invention of the present application, in the intake device for an engine with a mechanical supercharger according to the first invention, the on-off valve is an engine. In addition to having an opening degree characteristic of gradually closing the valve from full open with an increase in load, the relationship between the opening area of the upstream throttle section and the downstream throttle section is determined by the upstream throttle section when the on-off valve is fully open. The opening area of the on-off valve is set to be smaller than the opening area of the downstream throttle portion. Until the valve is opened, the opening area of at least the upstream throttle portion of the two throttle portions is controlled so that the opening area of the upstream throttle portion is equal to or larger than the opening area of the downstream throttle portion.

Therefore, according to the present invention, the following specific effects can be obtained in addition to the effects described in the above (a). That is, when the engine is decelerated, the on-off valve gradually opens from the fully closed state to the fully open state. In this case, the relationship between the opening area of the upstream throttle section and the opening area of the downstream throttle section is determined. The relationship when the on-off valve is fully open,
In other words, the opening degree of the on-off valve is at least equal to or less than the relationship in which the opening area of the upstream throttle part is made smaller than the opening area of the downstream throttle part to regulate the intake air amount by the upstream throttle part. Until the valve is opened from the closed state to the partial opening state, the opening area of the upstream throttle section is set to be equal to or larger than the opening area of the downstream throttle section so that the amount of intake air is regulated in the downstream throttle section. I have.

By setting the opening area, the opening area of the downstream throttle section is reduced at the time of deceleration, and the pressure on the downstream side of the mechanical supercharger sharply increases. In this case, the opening area of the upstream throttle section is increased. By increasing the pressure on the upstream side of the mechanical supercharger as close to the atmospheric pressure as possible, the expansion of the differential pressure between the upstream side and the downstream side of the mechanical supercharger is suppressed,
As a result, the reliability and durability of the mechanical supercharger can be further enhanced, and further improvement in the fuel efficiency of the engine can be expected.

(D) In the intake device for the engine with a mechanical supercharger according to the fourth invention of the present application, the intake device for the engine with the mechanical supercharger according to the first invention may be configured such that the output device is constantly operated by the engine output shaft. A drive transmission means without a clutch means is provided so that the supercharger is driven, and the on-off valve is opened throughout the low load range of the engine, and the upstream throttle is provided in the open area of the on-off valve. The opening area of at least one of the upstream throttle section and the downstream throttle section is controlled so that the opening area of the section is smaller than the opening area of the downstream throttle section.

Therefore, according to the present invention, the following specific effects can be obtained in addition to the effects described in the above (a). That is, the mechanical supercharger is always driven without the clutch means, so that the mechanical supercharger is driven by, for example, the provision of the clutch means by intermittent connection of the clutch means.
Compared with the configuration in which the drive is stopped, the durability and reliability of the drive transmission means of the mechanical supercharger are improved by the absence of the intermittent operation of the clutch means. Further, since the mechanical supercharger is constantly driven, the drive loss thereof tends to increase as compared with the case where the mechanical supercharger is not constantly driven. By reducing the absolute pressure on the upstream side of the turbocharger and reducing the blower work of the mechanical supercharger, the work is offset as much as possible, and the fuel efficiency of the engine is maintained well.

(E) In the intake device for an engine with a mechanical supercharger according to the fifth invention of the present application, in the intake device for an engine with a mechanical supercharger according to the first invention, A clutch means for stopping driving in a low engine load / low rotation range is provided, and when the supercharger stops driving, the opening / closing valve is opened, and the opening area of the upstream throttle section is reduced by the opening of the downstream throttle section. The opening area of at least the upstream throttle portion of the two throttle portions is controlled so as to be larger than the area.

Therefore, according to the present invention, the following specific effects can be obtained in addition to the effects described in the above (a). That is, when the mechanical supercharger is stopped, the opening and closing valve is opened and the opening area of the upstream throttle portion is set to be large, so that the pressure of the intake passage upstream of the downstream throttle portion is reduced. Is as close to atmospheric pressure as possible. Thus, since the downstream side of the mechanical supercharger is in a state close to the atmospheric pressure, the intake pressure on the downstream side is quickly increased to the atmospheric pressure with the start of driving of the mechanical supercharger during acceleration. The boost pressure rises to the above. Therefore, when the mechanical supercharger is stopped, the upstream side is throttled, and the supercharging pressure increases more rapidly than when the pressure of the air taken in through the on-off valve is negative. That is, the acceleration response of the engine can be improved.

(F) According to a sixth aspect of the present invention, in the intake device for an engine with a mechanical supercharger according to the first aspect of the invention, in the intake device for an engine with a mechanical supercharger according to the first aspect, the downstream side is provided. The throttle portion is constituted by an electrically controlled downstream throttle valve, and the required throttle air amount of the engine is controlled by the downstream throttle valve. On the other hand, the upstream throttle portion is controlled by a manually operated accelerator and mechanically. And an upstream throttle valve that is connected to the accelerator and operates in conjunction with the accelerator. The opening amount characteristic of the upstream throttle valve is such that when the accelerator opening is low in the increasing direction of the accelerator, the upstream The rate of increase in the opening amount is small so that the opening area of the throttle section is smaller than the opening area of the downstream throttle section, and the opening area of the upstream throttle section is at least at the time of the accelerator high opening when the opening degree is medium when the opening degree is medium. Aperture section The non-linear characteristic is such that the rate of increase in the opening amount increases so as to be larger than the opening area of the opening.

Therefore, according to the present invention, the following specific effects can be obtained in addition to the effects described in the above (a). That is, in a high-load region (that is, in a valve-closing region of the on-off valve), the upstream-side throttle valve is more likely to be opened than the downstream-side throttle valve that is electrically operated and controlled. Regulates the amount of intake air.

On the other hand, in the low-load region (ie, the valve-opening region of the on-off valve), the upstream-side throttle valve is more throttled than the downstream-side throttle valve. This is a state in which the intake amount is regulated. In this case, for example, in the transitional period of deceleration, the on-off valve is half-opened, the upstream throttle valve side is throttled, and the mechanical supercharger is still in a supercharged state. The differential pressure between the upstream side and the downstream side of the machine is rapidly increased, and there is a concern about the reliability of the mechanical supercharger. Here, the downstream throttle valve tends to open more than the upstream throttle valve. As a result, the pressure increase on the downstream side of the mechanical supercharger is suppressed, and the reliability and the like are secured.

In this case, the downstream throttle portion is constituted by a downstream throttle valve that is electrically operated and controlled, thereby controlling the intake air amount in the high load region and the mechanical supercharger in the low load region as described above. The setting of the opening amount characteristics of the upstream throttle valve and the downstream throttle valve for realizing the reliability and the like can be achieved with a high degree of freedom.

(G) The intake device for an engine with a mechanical supercharger according to the seventh invention of the present application is the intake device for an engine with a mechanical supercharger according to the second invention, wherein the downstream throttle portion is provided. A main throttle valve for controlling a required intake air amount of the engine based on an accelerator operation is provided. When the on-off valve is fully opened, the intake air amount is adjusted by the upstream throttle portion, and the engine is accelerated. When the state is detected, the opening area of the upstream throttle section is controlled to be larger than the opening area of the downstream throttle section.

Therefore, according to the present invention, the following specific effects can be obtained in addition to the effects described in the above (b). That is, at the time of acceleration of the engine, by adjusting the intake air amount in the downstream throttle portion provided with the main throttle valve, the adjustment of the intake air amount is performed at a position close to the inside of the cylinder of the engine in the intake passage. The acceleration response will be improved accordingly.

(H) In the intake device for an engine with a mechanical supercharger according to the eighth invention of the present application, in the intake device for an engine with a mechanical supercharger according to the third invention, the upstream throttle portion is provided. A throttle valve having a plate shape and an upstream throttle valve bypass passage bypassing the throttle valve and connecting the upstream side and the downstream side thereof, and an electromagnetic type bypass passage is provided in the upstream throttle valve bypass passage. An upstream flow control valve is provided, and the opening area of the upstream throttle portion is made larger than the opening area of the downstream throttle portion by the upstream flow control valve until the on-off valve opens to at least a partial opening degree, After the on-off valve has at least a partial opening degree, the opening amount of the upstream flow rate control valve is reduced so that the opening area of the upstream throttle section is smaller than the opening area of the downstream throttle section. Controls the opening area of the upstream throttle I am going to control it.

Therefore, according to the present invention, the following specific effects can be obtained in addition to the effects described in the above (c). That is, during the deceleration transition period in which the on-off valve is in the half-open state during the opening operation from the fully closed state to the fully open state, the mechanical supercharger is still in the supercharged state, and in this state, the upstream throttle valve is downstream. If the throttle valve is slightly throttled than the side throttle valve, the differential pressure before and after the mechanical supercharger (pressure ratio of the downstream pressure to the upstream pressure of the mechanical supercharger) sharply increases,
There is a possibility that the reliability of the mechanical supercharger is impaired. In this case, until the on-off valve reaches a partial opening degree, intake air is introduced through the bypass passage, and the differential pressure is suppressed,
By opening the upstream flow rate control valve and expanding the opening area on the upstream throttle valve side to bring the pressure on the upstream side of the mechanical supercharger as close to the atmospheric pressure as possible, the front and rear of the mechanical supercharger The expansion of the differential pressure is suppressed, and the reliability and the like of the mechanical supercharger are ensured.

(I) In the intake device for an engine with a mechanical supercharger according to the ninth aspect of the present invention, in the intake device for an engine with a mechanical supercharger according to the first aspect, the supercharger is provided. In addition, while providing a clutch means for stopping the drive in the low engine load / low speed range and driving the engine in the low engine load / high speed range, the on / off valve is opened in the entire low engine load range and The relationship between the opening area in the engine low-load area and the opening area of the upstream throttle section is larger than the opening area of the downstream throttle section in the drive stop area of the supercharger, and the drive area of the turbocharger The opening area of at least one of the upstream throttle section and the downstream throttle section is controlled so that the opening area of the upstream throttle section is smaller than the opening area of the downstream throttle section. doing.

Therefore, according to the present invention, the following specific effects can be obtained in addition to the effects described in the above (a). That is, by stopping the drive of the mechanical supercharger in the engine low load / low rotation range by the clutch means, for example, compared with the case where the mechanical supercharger is always driven without the clutch means, As a result, the drive loss of the mechanical supercharger is reduced by the amount corresponding to the stoppage of the drive, and the fuel efficiency of the engine is improved accordingly.

Further, since the connection of the clutch means is performed at the boundary between the low engine speed range and the high engine speed range, the connection of the clutch means is higher than when the connection of the clutch means is performed on the high speed side. Wear of the clutch means is reduced, its durability is improved, and its reliability is enhanced.

Further, in the drive stop area of the mechanical supercharger, the opening area of the upstream throttle section is set larger than the opening area of the downstream throttle section, so that the mechanical supercharger is driven. During acceleration, the air pressure on the upstream side is as close to the atmospheric pressure as possible, so that the acceleration response is improved. On the other hand, in the drive range of the mechanical supercharger, the opening area of the upstream throttle section is set smaller than the opening area of the downstream throttle section. Since the absolute pressure is reduced, the drive loss of the mechanical supercharger is reduced, and the improvement in fuel efficiency can be expected accordingly.

(J) The intake device for a mechanical supercharged engine according to the tenth invention of the present application is the intake device for a mechanical supercharged engine according to the second, fourth or fifth invention. The upstream throttle portion is provided with the upstream throttle valve,
The downstream throttle portion is provided with a downstream throttle valve, and the upstream throttle valve and the downstream throttle valve are connected to an accelerator that is mechanically operated manually. An upstream throttle valve bypass passage which bypasses the upstream throttle valve and connects the upstream side and the downstream side thereof is provided. By providing a flow rate control valve and controlling the upstream flow rate control valve, the relationship between the opening areas of the two throttle sections is reduced such that the opening area of the upstream throttle section is smaller than the opening area of the downstream throttle section. The present invention is characterized in that the relationship can be set to at least one of a relationship and a relationship in which the opening area of the upstream throttle portion is larger than the opening area of the downstream throttle portion.

Therefore, according to the present invention, the above (b),
The following specific effects are obtained in addition to the effects described in (d) or (e). That is, by connecting the upstream throttle valve and the downstream throttle valve to a mechanically operated accelerator, for example, without using a relatively expensive throttle valve that is electrically operated and controlled, the upstream throttle valve can be used. The opening area between the throttle valve and the downstream throttle valve can be adjusted quickly and inexpensively with good responsiveness.

In the above-mentioned upstream throttle valve bypass passage,
An electromagnetic upstream flow control valve that operates quickly is provided to adjust the opening amount of the upstream throttle valve bypass passage by the upstream flow control valve. Prior to the opening operation, the upstream flow rate control valve is instantaneously opened to rapidly increase the intake air amount, so that the acceleration response is improved.

Further, at the time of deceleration in which the downstream throttle valve is throttled and the pressure on the downstream side of the mechanical supercharger rises sharply, the upstream flow control valve is opened instantaneously to introduce the intake air. The increase in the differential pressure before and after the mechanical supercharger is suppressed more quickly, and the reliability of the mechanical supercharger is improved accordingly.

(K) The intake device for an engine with a mechanical supercharger according to the eleventh invention of the present application, wherein the intake device for an engine with a mechanical supercharger according to the tenth invention is as follows.
The downstream throttle valve side is provided with a downstream throttle valve bypass passage which bypasses the downstream throttle valve and connects the upstream side and the downstream side thereof. By providing a downstream flow control valve for adjusting the amount, by controlling the downstream flow control valve in cooperation with the upstream flow control valve provided in the upstream throttle valve bypass passage,
The relationship between the opening area of the two throttle portions, the relationship that the opening area of the upstream throttle portion is smaller than the opening area of the downstream throttle portion, and the opening area of the upstream throttle portion is the opening of the downstream throttle portion. At least one of the relations larger than the area can be set.

Therefore, according to the present invention, the following specific effects can be obtained in addition to the effects described in the above (j). That is, by controlling the downstream flow control valve provided in the downstream throttle valve bypass passage and the upstream flow control valve provided in the upstream throttle valve bypass passage in cooperation with each other, the upstream throttle valve and the downstream throttle are controlled. Compared to a case with only a valve,
The adjustment width of the opening amount between the upstream throttle unit and the downstream throttle unit is increased by the amount of the opening adjustment by the downstream flow control valve and the upstream flow control valve, and the reliability of the mechanical supercharger is improved. The improvement effect and the like are further enhanced.

(L) In the intake device for an engine with a mechanical supercharger according to the twelfth aspect of the present invention, a mechanical supercharger provided in an intake passage and driven through an output shaft of the engine. A bypass passage connecting an upstream portion and a downstream portion of the supercharger in the intake passage so as to bypass the turbocharger; and an on-off valve for controlling opening and closing of the bypass passage in accordance with an operation state of the engine. The valve is opened in a low engine load region and closed in a high engine load region, and the drive region of the turbocharger is set to at least a part of the engine high load region and the engine low load region. In the intake device for a mechanical supercharged engine, the opening area of the intake passage at the upstream portion is changed to a position upstream of the branch of the bypass passage on the upstream side of the supercharger in the intake passage. The throttle portion is provided with a downstream throttle portion that changes the opening area of the intake passage at the downstream portion at a portion downstream of the junction of the bypass passage on the downstream side of the supercharger in the intake passage. While adjusting the intake air intake amount to the engine at the side throttle portion and the downstream throttle portion, the driving of the supercharger is stopped in a low rotation region in a low engine load region, and the supercharger is driven in a high rotation region. At the same time, the opening / closing valve is opened throughout the low engine load range, and the relationship between the opening areas of the two throttle portions is such that the opening area of the upstream throttle portion is reduced when the drive of the turbocharger is stopped. At least one of the upstream throttle portion and the downstream throttle portion such that the opening area of the upstream throttle portion is smaller than the opening area of the downstream throttle portion when the supercharger is driven. One of the apertures So as to control the mouth area.

Therefore, according to the present invention, the drive of the mechanical supercharger is stopped by the clutch means in the low engine load and low revolution range, so that the mechanical supercharger can be used without the clutch means. Compared to the case of a configuration in which the mechanical supercharger is driven constantly, the drive loss of the mechanical supercharger is reduced as much as the drive is stopped, and the fuel efficiency of the engine is improved accordingly.

Further, the connection of the clutch means is performed at the boundary between the low engine speed range and the high engine speed range. Wear of the clutch means is reduced, its durability is improved, and its reliability is enhanced.

Further, in the drive stop region of the mechanical supercharger, the opening area of the upstream throttle portion is set larger than the opening area of the downstream throttle portion, so that the mechanical supercharger is driven. During acceleration, the air pressure on the upstream side is as close to the atmospheric pressure as possible, so that the acceleration response is improved. On the other hand, in the drive range of the mechanical supercharger, the opening area of the upstream throttle section is set smaller than the opening area of the downstream throttle section. Since the absolute pressure is reduced, the drive loss of the mechanical supercharger is reduced, and the improvement in fuel efficiency can be expected accordingly.

(M) In the intake device for an engine with a mechanical supercharger according to the thirteenth invention of the present application, in the intake device for an engine with a mechanical supercharger according to the twelfth invention,
At the same engine load, the opening area of the downstream throttle portion is made larger as the engine speed increases, while the supercharger is accelerated from a drive stop state to a drive state in a low engine load area. The opening area of the downstream throttle portion is temporarily increased in synchronization with the operation change from the drive stop state to the drive state of the turbocharger.

Therefore, according to the present invention, the following specific effects can be obtained in addition to the effects described in (1) above. That is, since the opening area of the downstream throttle valve is smaller than the opening area of the upstream throttle valve when the drive of the mechanical supercharger is stopped, there is sufficient reserve in the opening area of the downstream throttle valve. . Therefore, when the mechanical supercharger is accelerated from the drive stop state to the drive state in the low load range of the engine, the mechanical supercharger is temporarily synchronized with the operation change from the drive stop state to the drive state. By increasing the opening area of the downstream throttle portion, the torque shock caused by the sudden increase in the engine load due to the driving of the mechanical supercharger is reduced.
The engine output is suppressed by an increase in the engine output due to a temporary increase in the opening area of the downstream throttle valve, thereby enabling operation with less torque shock.

(N) In the intake device for an engine with a mechanical supercharger according to the fourteenth aspect of the present invention, in the intake device for an engine with a mechanical supercharger according to the thirteenth aspect,
The downstream throttle portion includes a main throttle valve that controls a required intake air amount of the engine based on an accelerator operation, and a downstream throttle valve bypass that bypasses the main throttle valve and connects the upstream side and the downstream side. A passage and a downstream flow control valve for adjusting the opening amount of the downstream throttle valve bypass passage are provided, and the downstream flow control valve temporarily increases the opening area of the downstream throttle portion. I have.

Therefore, according to the present invention, the following specific effects can be obtained in addition to the effects described in the above (m). That is, at the time of acceleration of the engine, by adjusting the intake air amount in the downstream throttle portion provided with the main throttle valve, the adjustment of the intake air amount is performed at a position close to the inside of the cylinder of the engine in the intake passage. The acceleration response will be improved accordingly.

(O) In the intake device for an engine with a mechanical supercharger according to the fifteenth invention of the present application, the intake device for an engine with a mechanical supercharger according to the twelfth invention may comprise:
An accelerator which is provided with an upstream throttle valve in the upstream throttle portion and a downstream throttle valve in the downstream throttle portion, respectively, and which is mechanically operated by manual operation of these upstream throttle valve and downstream throttle valve. On the other hand, the upstream throttle valve side is provided with an upstream throttle valve bypass passage bypassing the upstream throttle valve and connecting the upstream side and the downstream side thereof, and the upstream throttle valve bypass passage is provided in the upstream throttle valve side. By providing an electromagnetic upstream flow control valve for adjusting the opening amount of the passage, and controlling the upstream flow control valve, the relationship between the opening areas of the two throttle portions can be changed to the opening area of the upstream throttle portion. Can be set to at least one of a relationship where the opening area of the downstream throttle portion is smaller than the opening area of the downstream throttle portion and a relationship where the opening area of the upstream throttle portion is larger than the opening area of the downstream throttle portion. .

Therefore, according to the present invention, the following specific effects can be obtained in addition to the effects described in (1) above. That is, by connecting the upstream throttle valve and the downstream throttle valve to a mechanically operated accelerator, for example, without using a relatively expensive throttle valve that is electrically operated and controlled, the upstream throttle valve can be used. The opening area between the throttle valve and the downstream throttle valve can be adjusted quickly and inexpensively with good responsiveness.

In the upstream throttle valve bypass passage,
An electromagnetic upstream flow control valve that operates quickly is provided to adjust the opening amount of the upstream throttle valve bypass passage by the upstream flow control valve. Prior to the opening operation, the upstream flow rate control valve is instantaneously opened to rapidly increase the intake air amount, so that the acceleration response is improved.

Further, when the downstream throttle valve is throttled and the pressure on the downstream side of the mechanical supercharger suddenly increases, the upstream flow control valve is instantaneously opened and intake air is introduced. The increase in the differential pressure before and after the mechanical supercharger is suppressed more quickly, and the reliability of the mechanical supercharger is improved accordingly.

(P) The intake device for an engine with a mechanical supercharger according to the sixteenth invention of the present application is the intake device for an engine with a mechanical supercharger according to the fifteenth invention,
The downstream throttle valve side is provided with a downstream throttle valve bypass passage which bypasses the downstream throttle valve and connects the upstream side and the downstream side thereof. By providing a downstream flow control valve for adjusting the amount, by controlling the downstream flow control valve in cooperation with the upstream flow control valve provided in the upstream throttle valve bypass passage,
The relationship between the opening area of the two throttle portions, the relationship that the opening area of the upstream throttle portion is smaller than the opening area of the downstream throttle portion, and the opening area of the upstream throttle portion is the opening of the downstream throttle portion. At least one of the relations larger than the area can be set.

Therefore, according to the present invention, the following specific effects can be obtained in addition to the effects described in the above (o). That is, by controlling the downstream flow control valve provided in the downstream throttle valve bypass passage and the upstream flow control valve provided in the upstream throttle valve bypass passage in cooperation with each other, the upstream throttle valve and the downstream throttle are controlled. Compared to a case with only a valve,
The adjustment width of the opening amount between the upstream throttle unit and the downstream throttle unit is increased by the amount of the opening adjustment by the downstream flow control valve and the upstream flow control valve, and the reliability of the mechanical supercharger is improved. The improvement effect and the like are further enhanced.

[0069]

BEST MODE FOR CARRYING OUT THE INVENTION

A: First Embodiment FIG. 1 shows an entire system of an intake device of an engine with a mechanical supercharger according to a first embodiment of the present invention. In FIG. It is an intake passage. In the intake passage 2, a surge tank 3, a downstream throttle valve 20, an intercooler 4, a mechanical supercharger 5, an upstream throttle valve 10, an air flow sensor 7, and an air cleaner 8 are arranged from the downstream of the intake to the upstream. They are arranged sequentially.

[0070] the mechanical supercharger 5 above mechanical supercharger 5 is a supercharger driven by the engine 1, in this embodiment over request high internal compression type reduction of drive loss Although a feeder (for example, a Richum pump) is assumed, the present invention is not limited to such a structure, and a blow-type roots pump or the like can be adopted.

The mechanical supercharger 5 includes an electromagnetic clutch 6
(Corresponding to "clutch means" in the claims), and the mechanical supercharger 5 is driven by the engine 1 or stopped when the electromagnetic clutch 6 is turned on and off. ing. The operation of the electromagnetic clutch 6 is controlled by receiving a control signal from a control unit 40 described later.
As described later, the intake pipe pressure (air pressure in the surge tank 3 downstream of the downstream throttle valve 20 described later) is -1.
Driving in a high load range of 00 mmHg or more,
The drive control is performed in accordance with the intake pipe pressure so that the drive is stopped in a low load range of not more than mmHg.

The intake passage 2 is provided with a bypass passage 30 that bypasses the mechanical supercharger 5 and connects the upstream side and the downstream side of the mechanical supercharger 5. The passage 30 is provided with an on-off valve 31. The on-off valve 31 is opened and closed by a pressure-responsive actuator 32 in which a negative pressure and the atmosphere are selectively introduced by operating a three-way solenoid valve 33 that is duty-controlled. The valve closes when air is introduced and opens when negative pressure is introduced.

The on-off valve characteristics of the on-off valve 31 are shown in FIG.
As shown in the figure, when the intake pipe pressure is at a low pressure of -100 mmHg or less (that is, when the engine is under a low load), it is fully opened, and when the intake pipe pressure is -100 mmHg or more high pressure (that is, at the time of a high engine load). Is fully closed, and the operation of the on-off valve between the fully open state and the fully closed state is gradually performed with a predetermined operation time. Further, here, as described above, the opening and closing valve 31 is configured to open and close according to the intake pressure. However, in another embodiment, for example, the actuator is configured by an electric actuator such as a stepping motor, and The opening / closing valve 31 may be configured to be opened / closed by a map value set in advance according to the engine speed and the accelerator opening.

[0074] the downstream-side throttle valve 20 the downstream-side throttle valve 20 is composed of a plate-shaped throttle valve, and be one that is located downstream position of the merging portion of the bypass passage 30 in the intake passage 2 , "Downstream throttle portion" and "main throttle valve" in the claims. The downstream throttle valve 20 is mechanically connected to an accelerator 50 which is depressed by a driver, and is opened to an opening corresponding to the amount of depression of the accelerator 50. Therefore, the opening and closing valve characteristics of the downstream-side throttle valve 20 is assumed to vary linearly in response to the depression amount of the accelerator 50 as shown by the characteristic line L ₁ in FIG. 4. The depression amount of the accelerator 50 (that is, the accelerator opening) is detected by an accelerator opening sensor 42 and is input to a control unit 40 described later.

In the vicinity of the downstream throttle valve 20, there is provided a downstream throttle valve bypass passage 21 which bypasses the downstream throttle valve 20 and connects the upstream side and the downstream side (refer to “downstream in the claims”). Side throttle valve bypass passage ”and“ downstream throttle valve bypass passage ”), and the downstream throttle valve bypass passage 21 has the passage 2.
1 is provided with a downstream flow control valve 22 for adjusting the opening amount. The downstream flow control valve 22 is constituted by a duty solenoid valve, and is controlled to open and close in response to a control signal from a control unit 40 described later.

The upstream throttle valve 10 is formed of a plate-like throttle valve similarly to the downstream throttle valve 20, and is located downstream of the junction of the bypass passage 30 in the intake passage 2. It is disposed at the side position, and corresponds to the “upstream throttle valve” and the “upstream throttle section” in the claims, respectively. The upstream throttle valve 10 is connected to the accelerator 50 via a lever mechanism 51 described below, and is opened / closed with predetermined opening / closing valve characteristics in response to a depression operation of the accelerator 50.

The lever mechanism 51 includes a first lever 52 and a second lever 53, as shown in FIG. The first lever 52 is pivotally mounted on a valve shaft 10a of the upstream throttle valve 10, and is configured to rotate integrally with the valve shaft 10a (that is, the upstream throttle valve 10). The first lever 52 has an engagement groove 57 bent in a substantially "S" shape and a stopper 52a.

The second lever 53 is pivotally supported by a fulcrum shaft 55 arranged on the side of the valve shaft 10a of the upstream throttle valve 10. The second lever 53 has
An engagement pin 56 is provided to engage in an engagement groove 57 of the first lever 52, and is connected to the accelerator 50 via a connection wire 54. Therefore, when the accelerator 50 is depressed, the operating force is transmitted to the second lever 53 via the connection wire 54 as the turning power, and the second lever 53 is moved about the fulcrum shaft 55 as a center. It turns by the turning amount corresponding to the stepping amount of 50. With the rotation of the second lever 53,
The engaging pin 56 provided on the second lever 53 is connected to the first lever 53.
The first lever 52 slides in the engagement groove 57 of the lever 52.
Is rotated with a rotation characteristic defined by the shape of the engagement groove 57, and as a result, the upstream throttle valve 10 is opened and closed with a predetermined opening / closing valve characteristic. Note that in this embodiment, the upstream-side throttle valve 10 in response to the depression amount of the accelerator 50, the engagement groove 57 so as to open and close off valve characteristic shown by the characteristic line L ₂ in FIG. 4 Is set. For reference, the engagement position and the with the engaging groove 57 and the engaging pin 56 shown in FIG. 3, shown in association with each position - in the characteristic line L ₂ in FIG.
In this case, the characteristic line L ₂ in FIG. 4, of the operating region of the engine to be described later (see FIG. 6), an opening and closing valve characteristic in the second region and the third region, - the the characteristic line L ₂
Is a characteristic in the second region, and is a third region.
This is the characteristic in the area. The on-off valve characteristics in the first region will be described below.

As described above, the relative degree of opening (that is, the opening amount) between the upstream throttle valve 10 and the downstream throttle valve 20 in the second region and the third region is determined by the depression of the accelerator 50. With the increase in the amount (that is, the increase in the engine load), the opening of the upstream throttle valve 10 is smaller than the opening of the downstream throttle valve 20 in the second region on the low load side,
In the third region on the high load side, the opening amount of the upstream throttle valve 10 is set to be larger than the opening amount of the downstream throttle valve 20. Therefore, in the second region, the intake amount is regulated by the upstream throttle valve 10, and in the third region, the intake amount is regulated by the downstream throttle valve 20.

[0080] On the other hand, in those in this embodiment, of the operating region of the engine, in the first region, as shown by the characteristic line L ₃ in FIG. 4, the upstream-side throttle valve 10
The opening degree is maintained as a partial opening degree. That is, the upstream throttle valve 10 is connected to the first lever 5.
2 is fully closed when it is in the rotation position shown by the solid line in FIG. 2, but by restricting the rotation range of the first lever 52 to the valve closing side, specifically, the reference numeral in FIG. 52 '
By restricting the position of the upstream throttle valve 10 at the position shown by the dashed line indicated by reference numeral 10 'by regulating the opening degree of the upstream throttle valve 10 at the position shown by the dashed line shown in FIG. I have.

In order to realize the partial opening state of the upstream throttle valve 10, in this embodiment, the stopper 61 which is moved forward and backward by the operation of the pressure-responsive actuator 60 is connected to the first lever 52. The stopper 61 is disposed so as to face the stopper 52a.
The pressure chamber 61a is connected to the surge tank 3 via a negative pressure path 64 provided with a three-way solenoid valve 65 in the middle of the pressure chamber 61a. And pressure can be introduced alternatively. When the atmosphere is introduced into the pressure chamber 61a of the stopper 61, the stopper 61 retreats as shown in FIG. 2, and the first lever 52 rotates to the position shown by the solid line (that is, the upstream throttle). Rotation of the valve 10 to the fully closed position) is permitted. On the other hand, when a negative pressure is introduced into the pressure chamber 61a, the stopper 61 moves forward and regulates the rotation of the first lever 52 in the valve closing direction at the position shown by the dashed line in FIG. an upstream-side throttle valve 10 is intended to partially open up conditions (see characteristic line L ₃ in Fig. 4).

Further, in the vicinity of the upstream throttle valve 10, an upstream throttle valve bypass passage 11 which bypasses the upstream throttle valve 10 and connects the upstream side and the downstream side thereof is provided. (Corresponds to "upstream throttle valve bypass passage")
And the upstream throttle valve bypass passage 1
1 is provided with an upstream flow control valve 12 for adjusting the opening amount of the passage 11. The upstream flow control valve 12
Is constituted by a duty solenoid valve, and is controlled to open and close in response to a control signal from a control unit 40 described later.

Control unit 40 The control unit 40 includes the upstream throttle valve 10 and the downstream throttle valve 2 according to the operating state of the engine 1.
0, the on-off valve 31, the upstream-side flow control valve 12 and the downstream-side flow control valve 22, and the on / off control of the electromagnetic clutch 6 (that is, the drive / stop control of the mechanical supercharger 5).
The control unit 40 receives an engine speed signal from a speed sensor 41, an intake pipe pressure signal from a boost sensor 43 provided in the surge tank 3, and a signal from the accelerator opening sensor 42. An accelerator opening signal is input. The control unit 40 calculates the opening / closing operation amount of each valve based on each of the input signals, outputs the calculated amount as an opening / closing control signal, and also outputs the on / off control signal for the electromagnetic clutch 6.

Here, an operation region when the control unit 40 controls the intake system will be described. In this embodiment, as shown in FIG. 6, the operating region of the engine 1 is divided into three regions according to the torque and the engine speed. That is, in the "torque-engine speed" characteristic diagram, the intake pipe pressure is "-100".
mmHg ”line, and the intake pipe pressure is“ −100 mmH
g "lower than, and the regions of low low load and low-speed than the engine speed" N ₁ "," first region ", the intake pipe pressure is lower than" -100mmHg "and engine speed" The low load / high rotation range higher than N ₁
The “region” and the high-load region where the intake pipe pressure is higher than “−100 mmHg” are defined as a “third region”.

The operating relationship between the on-off valve 31 and the mechanical supercharger 5 in each of these areas is set as follows.

In the first area, the mechanical supercharger 5
Is stopped, and the on-off valve 31 is fully opened. Accordingly, in the first region, the supercharging by the mechanical supercharger 5 is not performed, and the air bypasses the mechanical supercharger 5 by the suction negative pressure on the engine side and passes through the bypass passage 30. Inhaled into the engine cylinder.

In the second region, the mechanical supercharger 5
And the on-off valve 31 is fully opened.
Therefore, in this second region, the mechanical supercharger 5
Is driven, but since the on-off valve 31 is fully open, supercharging by the mechanical supercharger 5 is not performed, and air bypasses the mechanical supercharger 5 by suction negative pressure on the engine side. Thus, it is sucked into the engine cylinder through the bypass passage 30.

In the second region, although the driving of the mechanical supercharger 5 is not originally necessary, the driving and stopping of the mechanical supercharger 5, ie, the electromagnetic clutch 6
In order to prevent the reliability or durability of the electromagnetic clutch 6 from deteriorating due to the intermittent operation being performed in the high rotation range, the electromagnetic clutch 6 is driven at the section rotation speed “N ₁ ” between the first region and the second region. It was made. Therefore, this second
In the region, the reduction of the drive loss of the mechanical supercharger 5 is the region most required in terms of the fuel efficiency of the engine. Therefore, in this embodiment, the drive loss of the mechanical supercharger 5 is reduced. to reduce, to set the relationship between the opening area between the upstream-side throttle valve 10 and the downstream-side throttle valve 20 as described above with (see characteristic line L ₂ in FIG. 4), the upstream flow control valve 12 And the downstream flow control valve 22
Is controlled (specific control will be described later).

In the third area, the mechanical supercharger 5
, And the on-off valve 31 is closed with an increase in load, and is fully closed on the high load side. Therefore,
In the third region, supercharging by the mechanical supercharger 5 is performed. In this case, it is necessary to reduce the drive loss of the mechanical supercharger 5 to improve the fuel efficiency of the engine, and to improve the reliability or durability of the mechanical supercharger 5. Therefore, in this embodiment, the opening area of the upstream throttle valve 10 and the downstream throttle valve 20 is reduced in order to reduce the drive loss of the mechanical supercharger 5 and secure the reliability thereof. (See FIG. 4)
Along with reference to the characteristic line L _2), so as to control the operation of the upstream flow control valve 12 and the downstream-side flow control valve 22 (specific control will be described later).

The operation of the upstream flow control valve 12 is as follows.
This is as shown in FIG. That is, the upstream flow control valve 1
Reference numeral 2 denotes a first region (i.e., a low-load / low-rotation region in which the electromagnetic clutch 6 is in an off state and the mechanical supercharger 5 stops driving) in accordance with the operation region. Is opened.

In the second region (that is, when the intake pipe pressure is -100 m
At mHg or lower and in a low-load / high-speed range where the mechanical supercharger 5 is driven with the electromagnetic clutch 6 being ON, the valve is closed.

The third region (that is, the intake pipe pressure is -100 m
In a high load range of mHg or more), the valve is opened.

[0093] Following the control of the intake system, the actual and control of intake system by the control unit 40 will be described with reference to the flowchart shown in FIG.

Note that the initial state at the start of control is as follows:
The electromagnetic clutch 6 is in an “OFF” state (that is, the mechanical supercharger 5 is in a driving stop state), and the upstream flow control valve 1
2 is in the “open” state, and the three-way solenoid valve 65 is in the “OF” state.
In the "F" state, the upstream throttle valve 10 is partially opened (FIG. 4).
It is a characteristic line L ₃ reference) and. Further, the flag F indicating the shift of the operation region is set to F = F when accelerating from the first region.
1, F = 2 when accelerating from the second area, F = 3 when decelerating from the second area, and F = 4 when decelerating from the third area. The operation control from the initial state is as follows.

After the control is started, first, in step S1,
The engine speed, intake pipe pressure, and the like are read from the sensors 41 to 43. Next, in step S2, it is determined whether the current operation area is the “first area”. If it is determined that the area is the “first area”, it is determined in step S3 whether or not the vehicle is currently in an acceleration state.

Here, when the vehicle is accelerating, the flag is set to F
= 1 (step S4), and the process returns. On the other hand, if it is determined that the vehicle is not in the acceleration state, step S
In 19, it is determined whether or not the flag F = 3 (that is, whether or not the state has been decelerated from the second area to the first area). If it is determined that the flag F is not equal to 3, it is further determined in step S23 whether the flag F is equal to 4 (that is, whether the speed is reduced from the third area to the first area). If it is determined that it is not, the routine is in the steady state in the first region and no control is necessary, so the routine returns.

On the other hand, if it is determined in step S19 that the flag F = 3, it means that the vehicle is decelerating from the second region to the first region, and the electromagnetic clutch 6 is turned "OFF" in step S20. The mechanical supercharger 5
Is stopped, and the three-way solenoid valve 65 is turned "OFF" to bring the upstream throttle valve 10 into a partially open state. Further, in step S21, the upstream flow control valve 12, which has been closed in the second region, is opened, and the flag F is reset in step S22, and the process returns.

In step S23, the flag F
If it is determined that the deceleration is equal to 4, the deceleration from the third area to the first area is performed, so that in step S24, the electromagnetic clutch 6 is turned "OFF" to stop the driving of the mechanical supercharger 5, and the three-way The solenoid valve 65 is turned "OFF" to bring the upstream throttle valve 10 into a partially opened state. However, since the upstream-side flow control valve 12 has already been opened in the third region, this open state is maintained.

On the other hand, if it is determined in step S2 that the current operation region is not the first region, the mechanical supercharger 5 is driven in either the second region or the third region. In addition, since the partial opening state of the upstream throttle valve 10 is to be released, first, in step S5
Then, the electromagnetic clutch 6 is set to the "ON" state, and the three-way solenoid valve 65 is set to the "ON" state so that the opening degree of the upstream throttle valve 10 can correspond to the operation of the accelerator 50.

Next, in step S6, the second
It is determined whether or not the area is an area. If it is determined that the area is the second area, it is further determined whether or not the flag F = 1 in step S11 (that is, when accelerating from the first area to the second area). Whether there is). Here, F = 1
Is determined, the upstream flow control valve 12, which has been open in the first region, is closed (step S1).
Together with 2), the flag F is reset and the process returns (step S13).

[0102] In this case, as shown by the characteristic line L ₁₁ in FIG. 11, to temporarily increase the amount of opening of the upstream-side throttle valve bypass passage 11 temporarily opened the upstream flow control valve 12 And a torque shock caused by a sudden increase in engine load when the mechanical supercharger 5 shifts from a drive stop state to a drive state due to acceleration from the first region to the second region. The increase in the engine output due to the temporary increase in the opening area is suppressed as much as possible, and the operation with less torque shock becomes possible.

On the other hand, if it is determined in step S11 that the flag F is not 1, the flow proceeds to step S14 to determine whether or not the flag F is 4 (that is, at the time of deceleration from the third area to the second area). Is determined. If the flag F is 4, the upstream flow control valve 12 that has been open in the third region is closed (step S12), and the flag F is reset and the process returns (step S13). ). In this case, FIG.
As shown in the figure, with the detection of the deceleration state of the engine, the open state of the upstream flow control valve 12 is maintained until the opening of the on-off valve 31 is opened to at least the partial open state, and the upstream throttle The opening area on the valve 10 side should be larger than the opening area on the downstream throttle valve 20 side. In other words, the upstream flow control valve 12 is normally closed from the open state with the deceleration from the third area to the second area, but this is repeated until the on-off valve 31 reaches the partial opening degree. Keep the valve open,
Inherent upstream throttle valve 10 side of the opening area after the second region shifts (characteristic line L ₁₁ see) the upstream flow control valve 1
The second opening is intended to increase as shown by the characteristic line L _22. By doing so, the opening area on the upstream throttle valve 10 side decreases during deceleration, and the pressure on the downstream side of the mechanical supercharger 5 rises sharply. And increasing the pressure on the upstream side of the mechanical supercharger 5 to the atmospheric pressure as much as possible, the expansion of the differential pressure between the upstream side and the downstream side of the mechanical supercharger 5 is suppressed. As a result, the reliability and durability of the mechanical supercharger 5 can be further improved, and further improvement in the fuel efficiency of the engine can be expected.

On the other hand, in step S14, the flag F
= 4, the process proceeds to step S1.
In 5 it is determined whether or not the vehicle is in an accelerating state. If the vehicle is in an accelerating state, the flag is set to F = 2 and the process returns (step S16).
At 17, it is determined whether or not the vehicle is in a deceleration state. If the vehicle is in a deceleration state, the flag is set to F = 3 and the process returns (step S18). On the other hand, if it is determined that the vehicle is not in the deceleration state, it is determined that the vehicle is in the steady state in the second region. In this case, the process returns.

If it is determined in step S6 that the current operation region is not the second region (ie, the third operation region is not the third operation region).
If it is a region, the flag F is set in step S7.
= 2 (that is, whether the vehicle is accelerating from the second region to the third region). If the vehicle is accelerating, the above-mentioned upstream flow rate that was in the valve closed state in the second region is determined. While opening the control valve 12 (step S10),
The flag F is reset and the process returns (step S1)
3).

In this case, as shown in FIG. 9, when the acceleration state of the engine is detected, the opening on the upstream throttle valve 10 side with the start of the valve closing operation from the full opening of the on-off valve 31. If the opening area is controlled so that the area is equal to or larger than the opening area on the downstream throttle valve 20 side, the intake amount regulation by the upstream throttle valve 10 is released in the partial opening state of the on-off valve 31, As a result, an increase in the amount of intake air is promoted, and the acceleration response of the engine is correspondingly improved.

On the other hand, if it is determined in step S7 that the flag F is not equal to 2 (that is, not during acceleration), it is further determined in step S8 whether or not the vehicle is in a deceleration state. To the flag F =
4 and the process returns (step S9). Also,
If it is determined that the vehicle is not in the deceleration state, the routine returns as it is in the steady state in the third region.

The above is the flow of control of the intake device in this embodiment.

B: Second Embodiment FIG. 12 shows an entire system of an intake device for an engine with a mechanical supercharger according to a second embodiment of the present invention. This embodiment has the same basic configuration as that of the first embodiment. The difference from the first embodiment is that in the first embodiment, the downstream In contrast to the configuration in which the side throttle valve 20 is mechanically connected to the accelerator 50, in the second embodiment, the downstream throttle valve 20 is driven by a stepping motor 49 that is electrically operated and controlled. It is the point which did so.

In the case where the downstream throttle valve 20 is driven by the stepping motor 49 in this manner, when the downstream throttle valve 20 is interlocked with the accelerator 50 as in the first embodiment, In comparison, since the adjustment width of the opening area of the downstream throttle valve 20 is large and the degree of freedom of the adjustment mode is large, the downstream throttle valve bypass passage 21 and the downstream side provided in the first embodiment are provided. No flow control valve 22 is provided. The configuration of the upstream throttle valve 10 side is the same as that of the first embodiment.

In this way, by configuring the downstream throttle valve 20 to be driven by the stepping motor 49, the same operation and effect as in the first embodiment can be obtained.
This can be realized more easily.

[Brief description of the drawings]

FIG. 1 is a system diagram of an intake device of a mechanical supercharged engine according to a first embodiment of the present invention.

FIG. 2 is a structural explanatory view of a lever mechanism shown in FIG. 1;

FIG. 3 is an operation explanatory view of the lever mechanism shown in FIG. 2;

4 is an opening characteristic diagram of a throttle valve operated by the lever mechanism shown in FIG. 2;

FIG. 5 is a control flowchart of the intake device shown in FIG. 1;

FIG. 6 is a "torque-engine speed" diagram.

FIG. 7 is an operation characteristic diagram of the on-off valve shown in FIG. 1;

8 is an operation characteristic diagram of the upstream flow control valve shown in FIG.

FIG. 9 is an opening amount characteristic diagram of an intake passage.

FIG. 10 is an opening amount characteristic diagram of an intake passage.

FIG. 11 is an opening amount characteristic diagram of an intake passage.

FIG. 12 is a system diagram of an intake device of an engine with a mechanical supercharger according to a second embodiment of the present invention.

[Explanation of symbols]

1 is an engine, 2 is an intake passage, 3 is a surge tank, 4 is an intercooler, 5 is a mechanical supercharger, 6 is an electromagnetic clutch (clutch means), 7 is an air flow sensor, 8 is an air cleaner, and 10 is an upstream throttle. A valve (upstream throttle section), 11 an upstream throttle valve bypass passage, 12 an upstream flow control valve,
20 is a downstream throttle valve (downstream throttle section, main throttle valve), 21 is a downstream throttle valve bypass passage (downstream throttle valve bypass passage), 22 is a downstream flow control valve, 30
Is a bypass passage, 31 is an on-off valve, 32 is an actuator, 33 is a three-way solenoid valve, 40 is a control unit, 41 is a rotation speed sensor, 42 is an accelerator opening sensor, 43 is a boost sensor, 49 is a stepping motor, and 50 is an accelerator. , 51 is a lever mechanism, 52 is a first lever, 53 is a second lever, 54 is a connection wire, 55 is a fulcrum shaft, 56 is an engagement pin, 57 is an engagement groove, 60 is an actuator, 61 is a stopper, and 64 is a stopper. The negative pressure path 65 is a three-way solenoid valve.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Koji Shizume 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (72) Inventor Keiji Araki 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Inside the corporation

Claims (16)

[Claims] 1. A supercharger provided in an intake passage and driven through an output shaft of an engine, and a portion of the intake passage that is upstream and downstream of the supercharger bypasses the supercharger. A bypass passage that connects and connects the bypass passage according to an operating state of the engine; and an opening / closing valve that opens and closes the engine in a low-load region and closes the valve in a high-load region. An intake device for an engine with a mechanical supercharger, wherein a drive region of the supercharger is set in at least a part of the high engine load region and the low engine load region, An upstream throttle portion for changing the opening area of the intake passage at the upstream portion is provided at an upstream portion of the branch portion of the bypass passage on the upstream side of the feeder, and the bypass passage at the downstream side of the supercharger in the intake passage is provided. A downstream throttle portion that changes the opening area of the intake passage of the downstream portion is provided at a portion downstream of the junction portion, and the intake throttle amount to the engine is adjusted by the upstream throttle portion and the downstream throttle portion, The opening area of the upstream throttle section is smaller than the opening area of the downstream throttle section in the valve opening area of the on-off valve. In the valve closing region, the opening area of at least one of the upstream throttle section and the downstream throttle section is controlled such that the opening area of the upstream throttle section is larger than the opening area of the downstream throttle section. An intake device for an engine with a mechanical supercharger. 2. The opening / closing valve according to claim 1, wherein the opening / closing valve has an opening characteristic in which the opening / closing valve gradually closes from full opening with an increase in engine load. The relationship is set so that the opening area of the upstream throttle section is smaller than the opening area of the downstream throttle section when the on-off valve is fully open, and when the acceleration state of the engine is detected, the on-off valve is closed. The opening area of at least the upstream throttle portion of both the throttle portions is controlled such that the opening area of the upstream throttle portion becomes equal to or larger than the opening area of the downstream throttle portion with the start of the valve closing operation from the full opening. An intake device for a mechanical supercharged engine. 3. The throttle device according to claim 1, wherein the on-off valve has an opening degree characteristic of gradually closing from full open with an increase in engine load, and an opening area between the upstream throttle portion and the downstream throttle portion. The relationship is set such that the opening area of the upstream throttle section is smaller than the opening area of the downstream throttle section when the on-off valve is fully open, and the deceleration state of the engine is detected in the drive region of the supercharger. When the opening degree of the on-off valve is at least partially opened, the opening area of the upstream throttle part is equal to or larger than the opening area of the downstream throttle part. An intake device for an engine with a mechanical supercharger, wherein an opening area of an upstream throttle portion is controlled. 4. The engine control system according to claim 1, further comprising: a drive transmission unit having no clutch unit so that the supercharger is always driven by an engine output shaft, and the on-off valve is opened over the entire low load region of the engine. And at least one of the upstream throttle portion and the downstream throttle portion such that the opening area of the upstream throttle portion is smaller than the opening area of the downstream throttle portion in the valve opening area of the on-off valve. An intake device for an engine with a mechanical supercharger, characterized by controlling an opening area of a part. 5. The system according to claim 1, further comprising: clutch means for stopping the driving of the supercharger in a low engine load / low rotation range; With a mechanical supercharger characterized by controlling at least the opening area of the upstream throttle portion of the two throttle portions so that the opening area of the upstream throttle portion is larger than the opening area of the downstream throttle portion. Engine intake device. 6. The throttle device according to claim 1, wherein the downstream throttle portion is constituted by a downstream throttle valve that is electrically operated and controlled, and the required intake air amount of the engine is controlled by the downstream throttle valve. The side throttle portion is constituted by an upstream throttle valve that is mechanically connected to an accelerator that is manually operated and that operates in conjunction with the accelerator, and that the opening amount characteristic of the upstream throttle valve is changed in a direction in which the accelerator opening increases. In the case where the accelerator opening is low, the opening amount increase rate is small so that the opening area of the upstream throttle part is smaller than the opening area of the downstream throttle part, and at the middle opening degree, at least the accelerator high opening degree A non-linear characteristic in which the rate of increase of the opening amount is increased so that the opening area of the upstream throttle section at the time is larger than the opening area of the downstream throttle section. Intake device. 7. The main throttle valve according to claim 2, wherein the downstream throttle portion is provided with a main throttle valve for controlling a required intake air amount of the engine based on an accelerator operation,
In the fully opened state of the on-off valve, the amount of intake air is measured by the upstream throttle portion, and when the acceleration state of the engine is detected, the opening area of the upstream throttle portion is reduced to the opening area of the downstream throttle portion. An intake device for an engine with a mechanical supercharger, which is controlled to be larger. 8. The throttle device according to claim 3, wherein the upstream throttle portion includes a plate-shaped throttle valve and an upstream throttle valve bypass passage that bypasses the throttle valve and connects the upstream side and the downstream side. In addition to the above, an upstream flow control valve of an electromagnetic type is provided in the upstream throttle valve bypass passage, and the opening of the upstream throttle portion is opened by the upstream flow control valve until the on-off valve opens to at least a partial opening degree. The area is larger than the opening area of the downstream throttle, and after the on-off valve has at least a partial opening, the opening of the upstream flow control valve is reduced to reduce the opening area of the upstream throttle. Wherein the opening area of the upstream throttle section is controlled so as to be smaller than the opening area of the downstream throttle section. 9. The engine according to claim 1, wherein the supercharger is provided with clutch means for stopping the driving in a low engine load / low rotation range and driving the supercharger in a low engine load / high rotation range. The opening / closing valve is opened in the entire area of the throttle valve. Larger than the opening area of the part,
In the drive region of the supercharger, the opening area of at least one of the upstream throttle section and the downstream throttle section is such that the opening area of the upstream throttle section is smaller than the opening area of the downstream throttle section. Control device for controlling the intake air of a mechanical supercharged engine. 10. The throttle device according to claim 2, wherein the upstream throttle portion is provided with the upstream throttle valve, and the downstream throttle portion is provided with a downstream throttle valve. An upstream throttle valve that connects the downstream throttle valve to an accelerator that is mechanically operated manually, while connecting the upstream throttle valve to the upstream throttle valve bypassing the upstream throttle valve. By providing a bypass passage, an electromagnetic upstream flow control valve for adjusting the opening amount of the passage is provided in the upstream throttle valve bypass passage, and by controlling the upstream flow control valve, the two throttle portions The relationship between the opening area of the upstream throttle section and the relationship that the opening area of the upstream throttle section is smaller than the opening area of the downstream throttle section, and the opening area of the upstream throttle section is larger than the opening area of the downstream throttle section. At least one of the relationships An intake device for an engine with a mechanical supercharger, characterized in that it can be fixed. 11. The downstream throttle valve according to claim 10, further comprising: a downstream throttle valve bypass passage connecting the upstream side and the downstream side of the downstream throttle valve by bypassing the downstream throttle valve. A throttle valve bypass passage is provided with a downstream flow control valve for adjusting an opening amount of the passage, and the downstream flow control valve is controlled in cooperation with the upstream flow control valve provided in the upstream throttle valve bypass passage. By doing so, the relationship between the opening areas of the two throttle portions, the relationship that the opening area of the upstream throttle portion is smaller than the opening area of the downstream throttle portion, and the opening area of the upstream throttle portion is the downstream side An intake device for an engine with a mechanical supercharger, wherein the intake device can be set to at least one of a relationship that is larger than an opening area of the throttle portion. 12. A supercharger provided in an intake passage and driven via an output shaft of an engine, and bypassing the upstream and downstream portions of the supercharger in the intake passage. A bypass passage that connects and connects the bypass passage according to an operating state of the engine; and an opening / closing valve that opens and closes the engine in a low-load region and closes the valve in a high-load region. An intake device for an engine with a mechanical supercharger, wherein a drive region of the supercharger is set in at least a part of the high engine load region and the low engine load region, An upstream throttle portion for changing the opening area of the intake passage at the upstream portion is provided at a position upstream of the branch portion of the bypass passage on the upstream side of the feeder. A downstream throttle portion for changing the opening area of the intake passage of the downstream portion is provided at a downstream portion from the junction portion of the above, and the intake throttle amount to the engine is adjusted by the upstream throttle portion and the downstream throttle portion. The driving of the supercharger is stopped in a low rotation range in a low engine load range, the supercharger is driven in a high rotation range, and the on-off valve is opened in the entire low engine load range. The relationship between the opening areas of the two throttle sections is such that when the driving of the supercharger is stopped, the opening area of the upstream throttle section is larger than the opening area of the downstream throttle section. Wherein the opening area of at least one of the upstream throttle section and the downstream throttle section is controlled so that the opening area of the downstream throttle section is smaller than the opening area of the downstream throttle section. Engine intake Location. 13. The supercharger according to claim 12, wherein the opening area of the downstream throttle portion is increased toward the high rotation speed side of the engine under the same engine load, while driving the supercharger in a low engine load range. When accelerating from a stop state to a drive state, the opening area of the downstream throttle portion is temporarily increased in synchronization with an operation change from the drive stop state to the drive state of the turbocharger. Air intake system for turbocharged engines. 14. The throttle device according to claim 13, wherein the downstream throttle portion includes a main throttle valve for controlling a required intake air amount of the engine based on an accelerator operation, and an upstream side and a downstream side of the main throttle valve bypassing the main throttle valve. A downstream throttle valve bypass passage connecting the downstream side and a downstream flow control valve for adjusting the opening amount of the downstream throttle valve bypass passage are provided, respectively. An intake device for an engine with a mechanical supercharger characterized by increasing an opening area of a portion. 15. The throttle device according to claim 12, wherein an upstream throttle valve is provided in the upstream throttle portion, and a downstream throttle valve is provided in the downstream throttle portion, respectively. And an upstream throttle valve bypass passage connecting the upstream and downstream sides of the upstream throttle valve bypassing the upstream throttle valve while connecting the mechanical throttle to an accelerator which is mechanically operated manually. The upstream throttle valve bypass passage is provided with an electromagnetic upstream flow control valve for adjusting the opening amount of the passage, and by controlling the upstream flow control valve, the relationship between the opening areas of the two throttle portions is controlled. At least one of a relationship in which the opening area of the upstream throttle portion is smaller than the opening area of the downstream throttle portion and a relationship in which the opening area of the upstream throttle portion is larger than the opening area of the downstream throttle portion. Can be set to either An intake device for an engine with a mechanical supercharger, characterized in that: 16. The downstream throttle valve according to claim 15, wherein the downstream throttle valve is provided with a downstream throttle valve bypass passage connecting the upstream side and the downstream side while bypassing the downstream throttle valve. A throttle valve bypass passage is provided with a downstream flow control valve for adjusting the opening amount of the passage, and the downstream flow control valve is controlled in cooperation with the upstream flow control valve provided in the upstream throttle valve bypass passage. By doing so, the relationship between the opening area of the two throttle portions, the relationship that the opening area of the upstream throttle portion is smaller than the opening area of the downstream throttle portion, and the opening area of the upstream throttle portion is the downstream side An intake device for an engine with a mechanical supercharger, wherein the intake device can be set to at least one of a relationship that is larger than an opening area of the throttle portion.