JPH0561454B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control device for a supercharged engine, and particularly to a control device for a supercharged engine installed in an automobile.

[Conventional technology]

BACKGROUND ART Conventionally, an automobile engine has been proposed in which an air supply passage communicating with a combustion chamber is provided with a mechanical supercharger driven by the engine.

[Problem that the invention seeks to solve]

However, in such conventional supercharged engines, when the car decelerates, the temperature of the mixture gas downstream of the mechanical supercharger increases, and even though the throttle valve is closed, the supercharger Because it is rotationally driven by
Therefore, the temperature of the air-fuel mixture increases. Furthermore, since there is less fuel available to absorb latent heat of vaporization, the gas temperature increases.

In this way, as the air-fuel mixture temperature rises, mechanical superchargers do not have sufficient heat countermeasures compared to turbochargers in terms of material (aluminum) and structure (gear oil and oil seals). , the temperature of the mixture gas on the discharge side must be kept at a relatively low temperature (around 150°C).

The present invention was made based on such a request, and aims to prevent an increase in the downstream mixed gas temperature of a supercharger during deceleration of an engine equipped with a mechanical supercharger, and at the same time prevent overboost (overboost). An object of the present invention is to provide a control device for a supercharged engine that can also prevent engine damage due to supercharging pressure.

[Means for solving problems]

In order to achieve this object, the control device for a supercharged engine of the present invention includes a throttle valve provided in an air supply passage connected to a combustion chamber of the engine, and a control device disposed downstream of the throttle valve to control the engine. a mechanical supercharger driven by a mechanical supercharger; a bypass passage capable of connecting an air supply passage upstream of the mechanical supercharger and an air supply passage downstream of the mechanical supercharger; and a bypass valve that is inserted into the bypass passage and can open and close the bypass passage, and the bypass valve opens the valve body of the bypass valve in response to negative pressure between the turbocharger and the throttle valve. It is composed of a first working chamber to open the valve body in response to positive pressure on the downstream side of the supercharger, and a second working chamber to open the valve body when the supply air temperature is below a predetermined value. When the negative pressure is applied to the first working chamber, the negative pressure is released to the atmosphere, and when the negative pressure between the supercharger and the throttle valve is equal to or higher than a predetermined value, the negative pressure is applied to the second working chamber. It is characterized by a bypass valve control mechanism that releases positive pressure to the atmosphere.

[Effect]

In the control device for a supercharged engine of the present invention described above, when the supply air temperature is below a predetermined value, the supply of working negative pressure to the first working chamber is cut off and the bypass valve does not open. When the temperature is higher than a predetermined value and the negative pressure between the supercharger and the throttle valve is greater than a predetermined value, such as during deceleration, the negative pressure acts on the first working chamber to open the bypass valve. Only in bad conditions where the temperature on the downstream side of the turbocharger where the intake air temperature is high and the amount of intake air is low tends to rise, the downstream pressure of the turbocharger is released to the upstream side and the temperature of the mixture gas on the discharge side is lowered. .

Furthermore, when the negative pressure between the supercharger and the throttle valve exceeds a predetermined value, the positive pressure acting on the second working chamber is released to the atmosphere, so that when decelerating from a fully open state to a fully closed state, When negative pressure above a predetermined value occurs, the discharge pressure downstream of the turbocharger is actively released to the atmosphere in order to release the positive pressure acting on the second working chamber to the atmosphere, reducing the pressure. In this way, the temperature of the mixture gas on the discharge side is lowered more effectively.

In addition, since the positive pressure acting on the second working chamber is released to the atmosphere, when the second working chamber is fully opened and fully closed in a relatively short period of time, the bypass valve is opened and closed by preventing residual positive pressure in the second working chamber. Actions are also taken to ensure reliable operation.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 to 6 show an automobile engine system equipped with a supercharged engine control device as a first embodiment of the present invention. Figure 2 is its overall configuration diagram, Figure 2 is its fuel system diagram, Figure 3 is a graph to explain its operation, and each a in Figures 4 to 6 explains the operation without a bypass passage. Graphs 4 to 6 for explaining the effects of the present invention and graphs b in FIGS. 4 to 6 correspond to each a in FIGS. FIG. 2 is an overall configuration diagram showing an automobile engine system equipped with a supercharged engine control device as a second embodiment of the present invention.

As shown in FIGS. 1 and 2, in the first embodiment, an air supply system and an exhaust system are connected to a combustion chamber 2 of a vehicle engine 1, and an air supply passage 3 of the air supply system is connected to a combustion chamber 2 of a vehicle engine 1.
An air mix damper 5 and an air cleaner 6 for introducing cold air Ac and warm air Aw from the upstream side.
, a suction type carburetor (fuel supply mechanism) 7 having a piston portion, a throttle valve (air intake amount control mechanism) 8, and driving force from a crank pulley (not shown) rotationally driven by the engine 1. A supercharger (S/C) 9 is provided as a mechanical supercharger that receives the power via a belt (not shown).

Further, the air supply passage 3 includes an upstream air supply passage 3A that is an upstream part of the super charger 9, and a downstream air supply passage 3A that is a downstream part of the super charger 9.
The air supply passage 3A includes an inter-cab throttle air supply passage 3C, which is an air supply passage between the carburetor 7 and the throttle valve 8.
and a throttle S/C air supply passage 3D, which is an air supply passage portion between the throttle valve 8 and the supercharger 9.

In addition, the exhaust passage 4 of the exhaust system has an exhaust port 4.
A muffler 4a is provided near b.

Then, communication is cut off between the fuel supply mechanism 20 having the carburetor 7 and the throttle valve 8, and the upstream air supply passage 3A and downstream air supply passage 3B of the supercharger (S/C) 9, so that the supply air bypasses the supercharger 9. A super charge bypass mechanism 30 that allows exhaust air to flow from the exhaust system to the downstream air supply passage 3
An EGR mechanism 40 that can recirculate the flow to B, and an EGR control mechanism 50 that controls the EGR state of this EGR mechanism 40.
and an air supply mechanism 64 that is controlled by the supply pressure downstream of the S/C and can send supply air from downstream of the air cleaner 6 to the exhaust passage 4.

The fuel supply mechanism 20 uses a fuel pump 77 to send fuel from a fuel tank 70 to a float chamber 75 through a filter 74.
At the same time, the fuel is sent from the fuel supply passage 22 inserted through the fuel cut solenoid (FCS) valve 21 of the carburetor mechanism to the air supply passage 3D on the downstream side of the throttle valve 8 near the throttle valve 8. It's summery.

Further, the fuel increase mechanism is provided with a throttle positioner 23 as an air supply increase mechanism that receives atmospheric pressure into the working chamber 23a through the passage 24 and projects the rod 23b. Rod 23b is always spring 2
3c, and when protruding comes into contact with the throttle member to increase the opening degree of the throttle valve 8. The passage 24 of this fuel increase mechanism receives an opening operation signal (high negative pressure, high rotation) from an OSAC delay valve 25, an engine rotation speed sensor 94, and a switch section 95 that constitute the air supply increase control mechanism. A solenoid valve 26 is inserted.

The supercharger bypass mechanism 30 includes a bypass passage 31 that allows communication between an air supply passage 3A on the upstream side of the supercharger 9 (air supply passage 3D between throttle S/C) and an air supply passage 3B on the downstream side; A bypass relief valve 32 as a bypass valve that is inserted into the bypass passage 31 and can adjust the communication state of the bypass passage 31, and this bypass relief valve 3.
2, and a bypass valve control mechanism 37 that can control the protrusion and retraction of the valve body 32c.

The bypass valve control mechanism 37 is a throttle S/C
An OSAC delay valve 34 connected to the air supply passage 3D and guided to the first working chamber (load detection means) 32a of the bypass relief valve 32 to open the valve body 32c upon receiving negative pressure on the upstream side is inserted. The second passage of the bypass relief valve 32 is connected to the downstream side air supply passage 3B and receives downstream positive pressure to open the valve body 32c. The passage 36 (second boost pressure reduction control mechanism 39) that leads to the working chamber 32b of the air cleaner 6 is opened when the downstream temperature of the air cleaner 6 is 30°C or less, and the pressure inside the passage 33 is reduced. A valve part 93a with a thermosensor 93 that opens to the atmosphere, a vacuum valve 27 for preventing pressure remaining on the positive pressure side of the bypass relief valve 32 when the throttle is fully opened and fully closed in a relatively short period of time, and a vacuum valve 27 for preventing residual pressure on the positive pressure side of the bypass relief valve 32. Passage 2 that sends large negative pressure from the throttle S/C air supply passage 3D to the working chamber 27a
8 is provided.

That is, the bypass valve control mechanism 37 includes a supply air temperature rise prevention mechanism for preventing a rise in supply air temperature when the engine 1 is under low load and at high speed;
It also serves as a supercharging pressure prevention mechanism that prevents supercharging pressure at high speeds.

In addition to the above configuration, the engine speed and vehicle speed are detected, and the throttle valve 8
A mechanism may be provided that achieves a reduction in the pressure ratio by slightly opening up the pressure upstream of the supercharger during deceleration (bringing it closer to atmospheric pressure).

In addition, the code|symbol 32d shows a spring.

The EGR mechanism 40 includes an EGR passage (exhaust gas recirculation passage) 41 and an EGR passage 41 inserted therein.
EGR valve (exhaust gas recirculation control valve) 42 and this
A communication passage 44 (EGR valve drive negative pressure passage, exhaust gas recirculation control passage) connects the working chamber 42a of the EGR valve 42 and the thermovalve 43 as a cooling water temperature detection means, and the air supply between the working chamber 42a and the cab throttle. It is composed of a communication passage (exhaust gas recirculation control passage) 45 that connects with the passage 3C.

In addition, the code|symbol 42b has shown the spring, and 42c has shown the valve body.

Here, the thermovalve 43 is for controlling the operation of the EGR valve 42, and is configured as a water temperature valve, and releases the pressure in the passage 44 to the atmosphere at a predetermined temperature or lower, thereby reducing the negative pressure in the working chamber 42a. The vacuum regulator valve 46, which will be described later, lowers the EGR valve 42 and closes the EGR valve 42.
The dynamic pressure in the passage 41 is transferred to the passage (exhaust pressure detection passage) 4.
1', the passage 46a is opened to the atmosphere, and the EGR rate (ratio of EGR amount to intake air amount) is kept constant, and is tuned in this way.

The EGR control mechanism 50 controls EGR as a control target.
It opens and closes the valve 42 to cut off communication with the EGR passage 41, and is a passage (supply pressure detection a passage for supplying exhaust pressure to the second working chamber 51b of the vacuum control valve 51 (exhaust pressure detection passage) 41'',
The communication passage (EGR valve drive negative pressure passage) that can supply the supply pressure of the inter-cab throttle air supply passage 3C to the third working chamber (control part) 51c of the vacuum control valve 51 and communicate with the working chamber 42a of the EGR valve 42; An exhaust gas recirculation control passage) 45 is provided, and this vacuum control valve 51 controls the supply pressure to the first working chamber 51a and
When the supply pressure is higher than the exhaust pressure by comparing the exhaust pressure of the EGR passage 41, that is, when the pressure relationship is such that fresh air blows through the exhaust passage 4, the valve body 51d is pushed down and the vacuum control valve 51 is pressed down. is opened, and the pressure inside the communication passage 45 is released to the atmosphere through the filter 51e.

Furthermore, the EGR control mechanism 50 is provided with a vacuum regulator valve 46, and the vacuum regulator valve 46 is connected to the communication path 4.
Control passage 46a receiving EGR control negative pressure from 5
, a working chamber 46b that receives control pressure from the control passage 46a, and a communication passage 4 that connects exhaust from the EGR passage 41.
1', a valve body 46d that allows a control passage to communicate with the working chamber 46b in an open state, and a valve body 46d connected to the working chamber 46b and connected to the working chamber 46b.
The vacuum regulator valve 46 determines the lift amount of the EGR valve 42.
With the dynamic pressure of the EGR passage 41, the communication passage (EGR valve passage)
45 to the atmosphere, and the EGR rate (relative to intake air amount)
The ratio of EGR amount) is kept constant.

The air supply mechanism 64 is also provided with an air cut valve 60, which is connected to a working chamber 60b that receives S/C downstream supply pressure via a passage 61 and a supply downstream of the air cleaner 6. The working chamber 60c receives air through the passage 63, the working chamber 60d receives exhaust pressure from the exhaust passage 4 through the passage 62, and the reed valve (check valve) 60a allows communication between the working chamber 60c and the working chamber 60d. It is configured.

This air cut valve 60 combusts unused CO and the like in the exhaust gas by supplying fresh air into the exhaust gas in the troughs of exhaust pressure pulsation (negative pressure).

In addition, the reference numeral 10 in the figure is the master back, 29 is the idle up mechanism, 76 is the passage, and 81 is the OSAC.
A delay valve 83 is a passage communicating with the operating chamber for controlling the protrusion of the piston portion of the carburetor 7, 84 is an orifice, 85 is a solenoid valve, 86 is a filter, 87
Vacuum valve for air mix damper, 87
a, 87b are the working chambers of the vacuum valve 87, 8
8 indicates a passage communicating with the valve portion 93a equipped with the salmon sensor 93 in the working chamber 87b.

Further, on the downstream side of the air cleaner 6, an idle compensator circuit thermovalve 91 and a valve section 93a with a thermosensor 93 are provided as supply air temperature detection means. 80℃
When the temperature exceeds the above, atmospheric air is introduced into the upstream air supply passage 3A downstream of the throttle valve 8 via the passage 92, that is, the air is supplied bypassing the carburetor 7 and the throttle valve 8, and the air-fuel ratio A/F is kept lean. It is something that becomes.

Further, a communication passage 92' is provided that connects this passage 92 and the passage 45 of the EGR valve drive negative pressure circuit.

Note that the communication path 92' is not provided in the idle compensator circuit thermovalve 91;
A thermo-valve exclusively for 2' may be provided, and in this case, the set temperature of the thermo-valve is appropriately set, for example, lower than that of the idle-compensator circuit thermo-valve 91.

Furthermore, reference numeral 94 is an engine rotation speed sensor (when the engine rotation speed exceeds a first predetermined value, the FCS 21
outputs a signal to turn off the engine, and the engine speed reaches the second
95 is a passage 3 connected to the working chamber 35a of the vacuum valve 35 constituting the deceleration detection mechanism.
3 shows a switch part that becomes open when receiving negative pressure from vacuum valve 32.
Negative pressure advance device for distributor connected to
97 is an ignition switch; 98 is a vehicle speed corresponding control unit (Vmax signal relay) for controlling the piston of the carburetor 7 to protrude and reduce the vehicle speed when the vehicle speed exceeds a set value; 99 is a throttle position sensor; Reference numeral 100 indicates a communication passage opening, and B indicates a battery.

Note that the symbols *1, *2, and *3 shown in Figure 1 are connected to each other, and the
In the figure, reference numeral 78 indicates a VST, and 79 indicates a fuel return valve.

Further, a mechanism may be provided to prohibit EGR in conjunction with idle increase.

In addition, the throttle valve 8 is used as the supply air amount control mechanism.
Alternatively, a bypass passage may be provided to bypass the flow, and the opening/closing of a valve inserted in the bypass passage may be controlled.

Since the control device for a supercharged engine according to the first embodiment of the present invention is configured as described above, the main controls performed on this engine 1 will be explained below.

Fuel control (1-1) Normal time (1-2) Fuel increase in specific operating range Boost pressure control (2-1) At high rotation and small throttle opening (2-2) At high rotation (supercharge pressure prevention) ) (2-3) Others EGR control (3-1) When the boost pressure is higher than the exhaust pressure (3-2) When the cooling water temperature is low (3-3) When the intake temperature is high Fuel control (1-1 ) Normal time The fuel control in this embodiment is to determine the amount of fuel supplied from the carburetor 7 to the intake passage 3 by controlling the opening degree of the throttle valve 8 using a cable connected to the accelerator pedal. The fuel supplied to the intake passage 3 is sent to the downstream side air supply passage 3B through the supercharger 9, vaporizes in this downstream side air supply passage 3B, removes latent heat of vaporization, and increases the high pressure downstream of the supercharger 9. It works to cool the air-fuel mixture.

As a result, the temperature of the air-fuel mixture in the downstream side air supply passage 3B is lowered, whereas the air-fuel mixture in the downstream side air supply passage 3B is overpressured and heated by the supercharger 9, so that the charging efficiency is increased and the engine output is increased.

(1-2) Fuel increase in a specific operating range Furthermore, in fuel control, fuel increase control is performed, and this fuel increase control is performed in a specific operating range of the engine 1 [symbol Z in Fig. 3]. Refer to], by driving the throttle valve 8 in the opening direction by the throttle positioner 23, the throttle opening is increased from the current opening.

That is, in response to the engine speed signal and negative pressure signal received through the engine speed sensor 94, when the engine speed is high and the negative pressure is low, the solenoid valve 26 is opened, the passage 24 is opened to the atmosphere, and the atmospheric pressure is increased. is supplied to the working chamber 23a of the throttle positioner 23, and the rod 2
3b is protruded, and the throttle member abutting the rod 23b is rotated to increase the opening degree of the throttle valve 8.

When the electromagnetic valve 26 is not operating, the throttle opening is small and when it comes to the left side of the port 100, the spring 23c of the working chamber 23a is compressed by the negative pressure of the throttle S/C air supply passage 3D, and the rod 23D does not protrude.

Boost pressure control (2-1) At high speed and small throttle opening Boost pressure control in this embodiment reduces the pressure in the downstream air supply passage 3B by controlling the communication state of the bypass passage 31. In order to recirculate the supercharged air to the upstream air supply passage 3A, the first supercharging pressure reduction control recirculates the supercharged air when the engine speed is high and the throttle opening is small, and the first supercharging pressure reduction control is performed when the engine speed is high and the throttle opening is large. There is a second supercharging pressure reduction control that recirculates the flow in the state, and the first supercharging pressure reduction control controls the negative pressure generated downstream of the throttle and upstream of the turbocharger during deceleration to the first supercharging pressure reduction control mechanism. 38, the bypass relief valve 32 is opened, and the supercharging air is recirculated from the downstream air supply passage 3B to the upstream air supply passage 3A, reducing the supercharging pressure and increasing the upstream pressure and the downstream pressure. By lowering the ratio of
The temperature of the mixture gas on the discharge side is lower than that shown in FIG. 6(a) without bypass (recirculation) [see FIG. 6(b)].

(2-2) At high revolutions (preventing supercharging pressure) In addition, the second supercharging pressure reduction control is performed when the engine rotates vortex at full throttle, and when friction is reduced when the engine is sufficiently aligned. When the second supercharging pressure reduction control mechanism 39 receives the supercharging pressure (supercharging pressure) equal to or higher than a predetermined value, the bypass relief valve 32 is opened and the upstream air supply is transferred from the downstream air supply passage 3B. By circulating the supercharging air into the passage 3A, the supercharging pressure is lower than that shown in FIG. 4a where there is no bypass (recirculation) [see FIG. 4b], and supercharging pressure is prevented.

Note that Figure 5a shows the mixture temperature in the air supply passage between the cab S/C without bypass (recirculation), and Figure 5b shows the temperature of the mixture in the air supply passage between the cab S/C without bypass (recirculation).
It shows the air-fuel mixture temperature in the air supply passage 3C between the cab S/C when this is done.

(2-3) Others When reducing the supercharging pressure, there is a possibility that a sudden deceleration occurs from the fully open range, so the vacuum solenoid valve 27 is operated and the passage 36
The pressure in the second working chamber 32 is released to the atmosphere.
Release the pressure in b to the atmosphere so that the temperature rise prevention function during deceleration will not be affected.

Note that by combining the first boost pressure reduction control and the fuel increase control in the fuel control, the temperature lowering effect can be further enhanced.

EGR control (3-1) When the boost pressure is higher than the exhaust pressure, the EGR valve 42 in the EGR control mechanism 40:
It is driven by the negative pressure near the inter-cab throttle air supply passage 3C sent through the passage 45,
The opening and closing of the vacuum regulator valve 46 is controlled to control the EGR rate.

The EGR valve drive negative pressure attachment part is always under negative pressure, so even under high load, the EGR valve 42 is in the open state, and the vacuum control valve 50 is connected to the downstream side supply pressure (inlet manifold positive pressure) and the exhaust side. Compare with positive pressure,
When the pressure is such that fresh air blows through to the exhaust side, the passage (EGR valve drive negative pressure circuit) 45 is opened to the atmosphere and the EGR valve 42 is closed to prevent blow-through. Furthermore, exhaust pulsation can also be reduced.

(3-2) When the cooling water temperature is low In addition, when the thermovalve 43 as a cooling water temperature detection means detects that the engine is not warmed up (below 55°C), the thermovalve 43 opens. , the passage 44 of the EGR valve drive negative pressure circuit is opened to the atmosphere, and the EGR
Close the valve 42 to stop (prohibit) EGR,
It is possible to prevent a decrease in feeling and to prevent a decrease in power performance.

(3-3) When the intake air temperature is high Furthermore, when the idle compensator circuit thermo valve 91 as an intake air temperature detection means detects that the intake air is in a cooling state (80°C or higher), the idle compensator circuit thermo valve 91 is activated. With the valve 91 in the open state,
The passage 45 of the EGR valve drive negative pressure circuit is opened to the atmosphere, and the EGR valve 42 is closed to stop (prohibit) EGR, thereby preventing a decrease in feeling and also a decrease in power performance.

In addition, when the cooling water temperature is higher than 55℃ and the intake temperature is lower than 80℃, EGR is activated at idle up, but this happens infrequently. Therefore, there is no need to change the carburetor between a car equipped with a cooler and a car not equipped with a cooler, and there is an advantage that the frequency of unstable idling is reduced.

Furthermore, cost reduction can be achieved by promoting common use of parts and simplification of parts.

Further, as shown in FIG. 7, according to the second embodiment, the passage 33 is provided with a branch portion 11, and the solenoid valve 26 and the OSAC delay valve 81 are interposed in the passage 33.
The communication path between the solenoid valve 26 and the branch portion 11 is eliminated, and the solenoid valve 26 and the branch part 11 are connected by the communication path 101, and the engine speed sensor 94' detects that the solenoid valve 26 is in the closed state when the engine speed is 3500 (rpm) or higher. As, the first supercharging pressure reduction control mechanism 3
When the engine speed is less than 3500 (rpm), the solenoid valve 26 is opened and the first supercharging pressure reduction control mechanism 38 is rendered inactive.

The other configurations are the same as the first embodiment, and according to this embodiment, malfunction of the bypass relief valve 32 is prohibited below the set rotation speed, and maintenance of the closed state of the bypass passage 31 is improved. The operation in the open state is also performed reliably in the same manner as in the first embodiment.

Therefore, the durability of the bypass relief valve 32 is improved.

Note that other effects are the same as in the first embodiment.

Furthermore, the branch part 11 in the second embodiment,
Solenoid valve 26, engine speed sensor 94',
The communication path 101 may be combined with the first embodiment as appropriate.

In addition, when the idle up mechanism detects the operating state or operation ready state of a load component (cooler, etc.) of the engine 1,
It may be combined with a cooling water temperature detection means or an intake air temperature detection means as appropriate so as to inhibit the above-mentioned EGR.

Furthermore, if a new thermovalve separate from the thermovalve 91 for controlling the steering wheel compensator is installed close to the thermovalve for controlling the steering wheel compensator, the carburetor can be used in common with that of a car without a cooler, and the idler can be prevented. It is also possible to completely eliminate the stable region.

〔Effect of the invention〕

As described in detail above, according to the supercharged engine control device of the present invention, the following effects and advantages can be obtained with a simple configuration.

(1) When the charger temperature is below a predetermined value, the supply of working negative pressure to the first working chamber is cut off, and the bypass valve does not open. When the negative pressure between the valve and the throttle valve is equal to or higher than a predetermined value, the negative pressure acts on the first working chamber to open the bypass valve. The effect of reducing the temperature of the mixture gas on the discharge side by releasing the pressure downstream of the supercharger to the upstream side is achieved only in a bad situation where the temperature on the downstream side of the charger tends to rise.

(2) When the negative pressure between the supercharger and the throttle valve exceeds a predetermined value, the positive pressure acting on the second working chamber is released to the atmosphere, so during deceleration from a fully open state to a fully closed state. When negative pressure above a predetermined value occurs, the discharge pressure downstream of the turbocharger is actively released to the atmosphere in order to release the positive pressure acting on the second working chamber to the atmosphere, reducing the pressure. As a result, the temperature of the mixture gas on the discharge side can be lowered more effectively.

(3) In order to release the positive pressure acting on the second working chamber to the atmosphere, a bypass valve is installed to prevent residual positive pressure in the second working chamber when fully opened and fully closed in a relatively short period of time. It also has the advantage of ensuring reliable opening and closing operations.

(4) According to (1) to (3) above, it is possible to effectively prevent the temperature rise of the downstream mixed gas of the mechanical supercharger.

[Brief explanation of the drawing]

Figures 1 to 6 show an automobile engine system equipped with a supercharged engine control device as a first embodiment of the present invention. Figure 1 is its overall configuration diagram, and Figure 2 is its fuel system. 3 is a graph for explaining the effect, each a in FIGS. 4 to 6 is a graph to explain the effect in the case without a bypass path, each b in FIGS. All of them are graphs for explaining the action in the engine with a bypass path corresponding to each a of FIGS. 4 to 6, and FIG. FIG. 1 is an overall configuration diagram showing a system of an automobile engine equipped with the device. 1... Vehicle engine, 2... Combustion chamber, 3...
Air supply passage, 3A... Upstream air supply passage, 3B... Downstream air supply passage, 3C... Air supply passage between cab throttles, 3D... Air supply passage between throttle S/C, 4
...Exhaust passage, 4a...Muffler, 4b...Exhaust port, 5...Air mix damper, 6...Air cleaner, 7...Carburetor, 8...Throttle valve,
9... Supercharger (S/C) as a mechanical supercharger, 10... Master back, 11... Branch, 20... Fuel supply mechanism, 21... Fuel cut solenoid (FCS) valve, 22... Fuel supply path, 23... Throttle positioner (air supply increase mechanism), 23a... Working chamber, 23b... Rod,
23c...spring, 24...passage, 25...
OSAC day valve, 26... Solenoid valve, 27...
... Vacuum valve, 27a... Working chamber, 28...
...Aisle, 29...Idle up mechanism, 30...
Supercharger bypass mechanism, 31... Bypass passage, 32... Bypass relief valve (bypass valve), 32a... First working chamber, 32b...
...Second working chamber, 32c... Valve body, 32d... Spring, 33... Passage, 34... OSAC day valve, 35... Vacuum valve, 36...
Orifice, 37... Bypass valve control mechanism, 38
...First supercharging pressure reduction control mechanism, 39...Second supercharging pressure reduction control mechanism, 40...EGR mechanism (exhaust gas recirculation mechanism), 41...EGR passage (exhaust gas recirculation passage) , 41'...Passage (exhaust pressure detection passage), 42...EGR valve (exhaust gas recirculation valve), 4
2a... Working chamber, 42b... Spring, 42c
... Valve body, 43 ... Thermo valve (water temperature valve),
44... Communication passage, 45... Communication passage (exhaust gas recirculation control passage), 46... Vacuum regulator valve, 46a... Control passage, 46b, 46c...
... Working chamber, 46d... Valve body, 46e... Filter, 50... EGR valve control mechanism (exhaust gas recirculation control mechanism), 51... Vacuum control valve (VCV) as differential pressure response mechanism, 51a... …
First working chamber, 51b...Second working chamber, 51c
...Third working chamber (control section), 51d... Valve body,
51e...Filter, 60...Air cut valve, 60a...Reed valve, 60b, 60c,
60d... Working chamber, 61-63... Passage, 64...
...Air supply mechanism, 69...Thermo valve, 70...
...Fuel tank, 71... Canister, 72... Outer vent valve, 73... Fuel supply path, 74...
...filter, 75...float chamber, 76...passage, 77...pump, 78...VST, 79...
Fuel return valve, 80... passage (supply pressure detection passage), 81... OSAC day valve,
82... Vacuum valve, 83... Passage, 84
... Orifice, 85 ... Solenoid valve, 86 ... Filter, 87 ... Vacuum valve for air mix damper, 87a, 87b ... Working chamber, 88 ... Passage, 91 ... Thermo valve for handle compensator circuit, 92 ... ...Passage, 92'...Communication path, 9
3... Thermosensor, 93a... Valve part, 94, 9
4'...Engine rotation speed sensor (engine rotation speed detection means) constituting the air supply increase control mechanism, 95...
...Switch part, 96...Negative pressure advance device for distributor, 97...Ignition switch,
98...Vehicle speed corresponding control unit (Vmax signal relay),
99...Throttle position sensor, 100...
...Opening for communication path, B...Battery, 101...Communication path.

Claims (1)

[Claims] 1. A throttle valve provided in an air supply passage connected to the combustion chamber of the engine, a mechanical supercharger located downstream of the throttle valve and driven by the engine, and the mechanical supercharger. a bypass passage capable of connecting an air supply passage upstream of the mechanical supercharger and an air supply passage downstream of the mechanical supercharger; and a bypass valve inserted in the bypass passage and capable of opening and closing the bypass passage. The bypass valve has a first working chamber and positive pressure downstream of the supercharger to open the valve body of the bypass valve in response to negative pressure between the supercharger and the throttle valve. and a second working chamber for opening the valve body in response to a temperature of the supply air, and releasing the negative pressure acting on the first working chamber to the atmosphere when the supply air temperature is below a predetermined value, and The supercharger includes a bypass valve control mechanism that releases the positive pressure acting on the second working chamber to the atmosphere when the negative pressure between the supercharger and the throttle valve is equal to or higher than a predetermined value. Control device for an engine with feeder.