JP2702538B2 - Control device for supercharged engine - Google Patents

Description

The present invention relates to a control device for a supercharged engine in which a plurality of superchargers are arranged in parallel.

(Prior Art) Conventionally, as described in Japanese Utility Model Application Laid-Open No. 60-178329, Japanese Patent Application Laid-Open No. 60-259722, etc., two turbochargers, a primary and a secondary, are juxtaposed to an engine. An exhaust cut valve and an intake cut valve are respectively provided on the turbine inlet side and the blower outlet side of the secondary side turbocharger, and these cut valves are opened and closed, so that the primary side turbocharger is provided in a low intake air flow rate region. There is known an engine called a twin turbo type or a sequential turbo type in which supercharging is performed only by a supercharger and a secondary turbocharger is operated in a high flow rate region.

(Problems to be Solved by the Invention) By the way, in such a sequential turbo, an intake cut valve that opens and closes an intake passage in which a secondary-side blower is provided is provided in a predetermined high flow rate region, and furthermore, above the intake cut valve. When the downstream differential pressure becomes equal to or higher than a predetermined value, it is required to open reliably, and to close surely in a low intake air flow rate region. However, in the conventional device, since no special measures are taken to reliably close the intake cut valve in the low flow rate region in which only the primary-side supercharger is operated, the pressure is increased by the primary-side supercharger. Backflow of intake air could not be prevented reliably. As a countermeasure, for example, a differential pressure valve may be used to reliably detect a differential pressure before and after the intake cut valve. However, if only the differential pressure valve is used, the intake cut valve opens in an operating state such as during deceleration. Therefore, the backflow may occur at the next acceleration.

Further, for example, in the above-described Japanese Patent Application Laid-Open No. 60-259722, the intake cut valve is constituted by a check valve,
Since the intake cutoff valve is closed by the supercharging pressure in the region where only the primary turbocharger operates, it can be said that there is little danger of backflow.However, when such a check valve is used, the intake resistance increases. There is a problem that cannot be avoided.

The present invention has been made in view of the above problems,
In a sequential turbo, an intake cut valve that opens and closes an intake passage in which a blower of a supercharger on a high flow rate side is provided,
An object of the present invention is to provide a control device for a supercharged engine that can be reliably closed in a region where only a low flow rate supercharger is operated.

(Means for Solving the Problems) In order to achieve the above object, a solution of the invention according to claim 1 is to operate at least a first supercharger that operates in a low flow rate region of the intake air amount and a high turbocharger region that operates in a high flow rate region. In a supercharged engine in which a second supercharger is arranged in parallel, a first intake passage in which the first supercharger is interposed and the second supercharger are interposed. A second intake passage; and a differential pressure type intake cut valve disposed downstream of the second supercharger in the second intake passage to detect a pressure state in the upstream and downstream of the arrangement location and open and close. . Further, an operating state detecting means for detecting an operating state of the engine, and an output of the operating state detecting means,
Switching control means for opening the intake cut valve in a high flow rate region to switch the second supercharger from a non-operating state to an operating state, and receiving an output of the operating state detecting means, Control means for forcibly closing the intake cut valve regardless of the downstream differential pressure.

Here, in the invention according to claim 2, the control means according to claim 1 operates such that the intake cut valve is closed by the intake negative pressure downstream of the throttle valve in a low flow rate region in which only the first supercharger is operated. It shall be configured. Also,
According to a third aspect of the present invention, in the second aspect, the intake negative pressure downstream of the throttle valve is accumulated in a predetermined volume chamber. Further, in the invention of claim 4, the control means in claim 1 is a control valve for controlling the introduction of pressure to an actuator for controlling the operation of the intake cut valve.

According to a fifth aspect of the present invention, there is provided an exhaust turbo-type first supercharger which operates at least in a low flow rate region of an intake air amount and an exhaust turbo type second supercharger which operates in a high flow rate range. And in a supercharged engine with
A first exhaust passage in which a turbine of the first supercharger is provided, a second exhaust passage in which a turbine of the second supercharger is provided, and a first exhaust passage upstream of the first supercharger. (1) a communication passage for communicating the exhaust passage with a second exhaust passage upstream of the second supercharger, an exhaust cut valve for opening and closing a second exhaust passage downstream of the communication passage, and the first supercharger A first intake passage in which a blower of the second turbocharger is provided and a second intake passage in which a blower of the second supercharger is provided.
An intake passage; and a differential pressure-type intake cut valve disposed downstream of the second supercharger in the second intake passage and operating to open and close by detecting a pressure state of the upstream and downstream of the arrangement location. Further, an operating state detecting means for detecting an operating state of the engine, and receiving the output of the operating state detecting means, opening the exhaust cut valve and the intake cut valve in a high flow rate region, and
Switching control means for switching the turbocharger from a non-operating state to an operating state, and receiving the output of the operating state detecting means, and forcibly operating the intake cut valve in the low flow rate region regardless of the differential pressure upstream and downstream of the intake cut valve. And control means for performing a closing operation.

(Operation) According to the first to fifth aspects of the present invention, the first supercharger operates when the engine is at least in the low flow rate region, and the second supercharger operates when the engine is in the high flow rate region. Activate at some time. In the high flow rate region where the second supercharger is operated, the intake cut valve (and the exhaust cut valve)
Is opened to perform supercharging by the second supercharger. Also,
In a low flow rate region in which the second supercharger is deactivated and supercharging is performed only by the first supercharger, the intake cut valve is forcibly closed regardless of the upstream and downstream differential pressures.

The forcible closing operation of the intake cut valve can be performed, for example, by the intake negative pressure downstream of the throttle valve.

(Example) Hereinafter, an example is described based on drawings.

 FIG. 1 is an overall system diagram showing an embodiment of the present invention.

In this embodiment, an engine 101 is a reciprocating two-cylinder engine, and exhaust passages 102 and 103 are provided independently for each cylinder. The first exhaust passage 102 of one of the two exhaust passages 102 and 103 has the first
A turbine 105 of a primary turbocharger 104 as a supercharger, and a turbine 107 of a secondary turbocharger 106 as a second supercharger are disposed in the other second exhaust passage 103. I have. First and second two exhaust passages
The pipes 102 and 103 join together downstream of the turbines 105 and 107 and are connected to a silencer (not shown). Also,
The intake passage 109 is divided into two downstream of an air cleaner (not shown), and a blower 111 of the primary turbocharger 104 is provided in the middle of a first branch passage (first intake passage) 110, and a second branch passage is provided. A blower 113 of the secondary turbocharger 106 is provided in the middle of the (second intake passage) 112.
The branch passages 110 and 112 are formed so as to face each other at the branch portion and extend substantially straight on both sides. Further, the two branch passages 110 and 112 merge again downstream of the respective blowers 111 and 113. And the intake passage 109 that has become one again
Is provided with an intercooler 114, a surge tank 115 is provided downstream thereof, and a throttle valve 116 is provided between the intercooler 114 and the surge tank 115. Also, the downstream end of the intake passage 109 branches off to
And two independent intake passages 117 and 118 corresponding to the respective cylinders. In addition, fuel injection valves 119 and 120 are disposed in these independent intake passages 117 and 118, respectively.

On the upstream side of the intake passage 109, an air flow meter 121 is disposed upstream of a branch portion of the first and second branch passages 110 and 112 and serves as operating state detecting means for detecting an intake air amount.
Is provided.

The two exhaust passages 102 and 103 are communicated with each other by a relatively small-diameter communication passage 122 upstream of both the primary and secondary turbochargers 104 and 105. An exhaust cut valve 123 is provided in the second exhaust passage 103 in which the secondary-side turbine 107 is provided, just downstream of the opening position of the communication passage 122. Further, a bypass passage 125 extending from the middle of the communication passage 122 and communicating with a combined exhaust passage 124 downstream of the turbines 105 and 107 is provided.
25 is provided with a wastegate valve 127 linked to a diaphragm-type actuator 126. The exhaust passage 103 connected to the upstream portion of the wastegate valve 127 of the bypass passage 125 and the secondary turbine 107
A leak passage 128 is provided for communication with the downstream of the exhaust cut valve 123, and the leak passage 128 is provided with an exhaust leak valve 130 linked to a diaphragm type actuator 129.

The exhaust cut valve 123 is a diaphragm type actuator 1
It is linked to 31. On the other hand, an intake cut valve 132 is provided downstream of the blower 113 in the branch passage 112 where the blower 113 of the secondary turbocharger 106 is provided. The intake cut valve 132 is constituted by a butterfly valve, and is also linked to a diaphragm type actuator 133. A relief passage 134 is formed in the branch passage 112 on the secondary side so as to bypass the blower 113, and a diaphragm-type intake relief valve 135 is provided in the relief passage 134.

The pressure chamber of the actuator 129 that operates the exhaust leak valve 130 is connected to the primary turbocharger 1 via a conduit 136.
The blower 111 is connected to the downstream side of the blower 111 of the branch passage 110 in which the blower 111 is disposed. When the pressure downstream of the blower 111 becomes equal to or higher than a predetermined value, the actuator 129 is operated to open the exhaust leak valve 130, thereby the exhaust cut valve 1
When the valve 23 is closed, a small amount of exhaust gas flows through the bypass passage 128 and is supplied to the secondary turbine 107. Therefore, secondary turbocharger 106 starts rotating before exhaust cut valve 123 opens. During this time,
By opening the intake relief valve 135 as described later, the rotation of the secondary turbocharger 106 increases, the transient response when the exhaust cut valve 123 opens is improved, and the torque shock is reduced.

The pressure chamber of the actuator 133 for operating the intake cut valve 132 is connected by a conduit 137 to the output port of an electromagnetic solenoid type three-way valve 138. Also, the exhaust cut valve 123
Is connected to the output port of another three-way valve 140 of the electromagnetic solenoid type via a conduit 139. Further, the pressure chamber of the actuator 141 that operates the intake relief valve 135 is connected to an output port of another three-way valve 143 of an electromagnetic solenoid type by a conduit 142.
The intake relief valve 135 is connected to the exhaust cut valve 123 as described later.
The relief passage 134 is kept open until a predetermined time before the intake cut valve 132 is opened. Thus, when the secondary turbocharger 106 is pre-rotated by the exhaust gas flowing through the leakage passage 128, the pressure upstream of the intake cut valve 132 is prevented from rising and entering the surging region.
Increase the rotation of 113.

The actuator 1 for operating the wastegate valve 127
26 is another three-way valve 145 of the electromagnetic solenoid type by a conduit 144
Connected to the output port.

The above four electromagnetic solenoid type three-way valves 138,140,143,145
Is controlled by a control unit 146 configured using a microcomputer. To the control unit 146, in addition to the engine speed R and the intake air amount Q, the throttle opening TVO, the supercharging pressure P1 downstream of the primary-side blower 111, and the like are input, and based on these, control as described below is performed.

One input port of the electromagnetic solenoid type three-way valve 138 for controlling the intake cut valve 132 is connected to a negative pressure tank 148 via a conduit 147, and the other input port is connected to a differential pressure detection valve described later via a conduit 149. It is connected to 150 output ports 170. The intake negative pressure downstream of the throttle valve 116 is introduced into the negative pressure tank 148 via a check valve 151. Further, one input port of the three-way valve 140 for controlling the exhaust cut valve 123 is open to the atmosphere, and the other input port is connected to a conduit.
The conduit connected to the negative pressure tank 148 via 152
Connected to 147. On the other hand, one input port of the three-way valve 143 for controlling the intake relief valve 135 is connected to the negative pressure tank 148, and the other input port is open to the atmosphere.
One input port of the three-way valve 145 for controlling the wastegate valve 127 is open to the atmosphere, and the other input port is connected to the conduit 136 communicating with the downstream side of the blower 111 on the primary side by a conduit 154. Have been.

As shown in FIG. 2, the casing 161 of the differential pressure detecting valve 150 has first and second two diaphragms 16.
It is divided into three chambers 164,165,166 by 2,163.
A first input port 167 is opened in the first chamber 164 on one end side, and a compression spring 168 is disposed between the inner surface of the end of the casing 161 and the first diaphragm 162. . A second input port 169 is opened in the middle second chamber 165, an output port 170 is provided in the center of the end wall of the casing 161, and a third input port 169 is provided in the third chamber 166 on the other end side. The atmosphere release port 171 is open. And the first
Of the third chamber 166 extends toward the output port 170 of the third chamber 166.
172 is fixed.

As shown in FIG. 1, the first input port 167 is connected to the downstream side of the intake cut valve 132 by a conduit 173, and the supercharging pressure P1 downstream of the primary side blower 111 is supplied to the first chamber 164.
To be introduced. Also, the second input auto 169 is connected by a conduit 174 upstream of the intake cut valve 132, thus
The pressure P2 on the upstream side of the intake cut valve 132 when the intake cut valve 132 is closed is introduced. When the pressure difference between the pressures P1 and P2 introduced from the input ports 167 and 169 is equal to or greater than a predetermined value, the valve 172 opens the output port 170. This output port 170 is connected via a conduit 149 to one of the input ports of a three-way valve 138 for controlling the intake cut valve 132. Therefore, in a state where the three-way valve 138 connects the conduit 137 connected to the pressure chamber of the actuator 133 for operating the intake cut valve 132 to the conduit 149 connected to the output port of the differential pressure detection valve 150, the differential pressure P2-P1 Is larger than a predetermined value, air is introduced into the actuator 133, and the intake cut valve 132 is opened. A three-way valve 138 connects the conduit 137 on the actuator 133 side to the negative pressure tank 148.
When communicating with the actuator 47, a negative pressure is supplied to the actuator 133, and the intake cut valve 132 is forcibly closed regardless of the differential pressure.

On the other hand, the exhaust cut valve 123 has a three-way valve 140 for controlling the exhaust cut valve 123 and an actuator 131 for operating the exhaust cut valve 123.
When the conduit 139 leading to the pressure chamber is connected to the conduit 152 on the negative pressure tank 148 side, the actuator 131 is closed by supplying a negative pressure. Also, the three-way valve 140
When the exhaust gas releases the conduit 139 to the atmosphere, the exhaust cut valve 123 is opened, and supercharging is performed by the secondary turbocharger 106.

By the control by the above control unit 146,
In the high flow rate region, the exhaust cut 123 and the intake cut valve 132 are opened to constitute switching control means for switching the secondary turbocharger 106 from a non-operation state to an operation state, and the switching control means is provided on the intake cut valve 132 in a low flow rate region. A control means for forcibly closing the intake cut valve 132 regardless of the downstream differential pressure is provided.

FIG. 3 is a control map showing the open / closed state of the intake cut valve 132, the exhaust cut valve 123, the intake relief valve 135, and the wastegate valve 127 together with the open / closed state of the exhaust leak valve 130. This map is stored in the control unit 146, and based on this map, the above-mentioned four electromagnetic solenoid type three-way valves 138, 140, 143, 145 are controlled.

In a region where the engine speed R is low or the intake air amount Q is small, the intake relief valve 135 is open, and the secondary gas turbocharger 106 is pre-rotated by opening the exhaust leakage valve 130. Then, when the engine speed reaches R2 or the intake air amount reaches the line of Q2, the intake relief valve 135 is closed, and thereafter, the pressure downstream of the secondary-side blower 113 increases until the exhaust cut valve 123 opens. Then, when reaching the line of Q4-R4, the exhaust cut valve 123 is opened, and then, when reaching the Q6-R6 line, the intake cut valve 132 is opened.
The supercharging by 06 starts and enters the supercharging area by both the primary and secondary turbochargers at the Q6-R6 line.

The intake cut valve 132, the exhaust cut valve 123, and the intake relief valve 135 have some hysteresis from the high flow side to the low flow side, that is, Q5-R5, Q3-R shown by broken lines in FIG.
3. Switches on each line of Q1-R1.

The broken portion of each line is on a so-called no-load line or load-load line.

The wastegate valve 127 is opened when the engine speed R and the throttle opening TVO are equal to or higher than a predetermined value, and when the supercharging pressure 1 downstream of the primary blower is equal to or higher than a predetermined value.

4 and 5 are flowcharts for executing the above-described control of the intake cut valve 123, the exhaust cut valve 132, and the intake relief valve 135 in this embodiment. S indicates each step. In addition, F is a flag, and the meaning of the state of the flag (F-1 to 6) is as shown in FIG. 3, and the previous transitions respectively correspond to Q1-R
The transition from the high flow side to the low flow side of one line (F-1), the transition from the low flow side to the high flow side of the Q2-R2 line (F = 2), the Q3-R3 line Transition from high flow side to low flow side (F = 3), transition from low flow side to high flow side of Q4-R4 line (F = 4), Q5-
The transition from the high flow side to the low flow side of the R5 line (F = 5) and the transition from the low flow side to the high flow side of the Q6-R6 line (F = 6) Corresponding. Hereinafter, description will be made step by step.

First, in FIG. 4, the process is started, and initialization (initialization) is performed in S1. At this time, the flag is set to 1.

Next, at S2, the intake air amount Q and the engine speed R are input. Then, map values Q1 to Q6 and R1 to R6 are read in S3.

Next, in S4, it is checked whether the flag F is 1, that is, whether the previous transition was from the high flow side to the low flow side of the Q1-R1 line. Note that initially F = 1, so this determination is YES.

And if F = 1, then go to S5, this time Q
Is greater than Q2, if NO, then
In S6, it is checked whether R is larger than R2 this time. And S5
If YES in S6 or YES in S6, the process proceeds to S7, where the flag F is set to 2, and in S8, control is performed to close the intake relief valve (a positive pressure is introduced into the actuator). Also, S5 and
If the determination in S6 is NO, the process returns.

If the determination in S4 is NO, the process proceeds to S9 and the flag F
Is an even number, that is, whether the previous transition was a transition on any line from the low flow rate side to the high flow rate side.

If YES in S9, the process goes to S10 and determines whether or not F = 2, that is, whether or not the previous shift was from the low flow side to the high flow side of the Q2-R2 line. If it is 2, go to S11.

In S11, it is determined whether Q is greater than Q4 this time, and N
If it is O, then in S12, it is checked whether or not this time R is larger than R4. Then, when either S11 or S12 is YES, the process proceeds to S13, where the flag F is set to 4, and control is performed to open the exhaust cut valve in S14 (negative pressure is introduced into the actuator).

Also, when the determination of both S11 and S12 is NO,
Go to S15 to see if Q is less than Q1 this time.

If YES in S15, whether or not R is smaller than R1 this time is checked in S16. If YES, the process proceeds to S17 to set the flag F to 1, and in S18, controls to open the intake relief valve (introduces a negative pressure to the actuator). Also, S15 and S
If all the determinations in 16 are NO, the process returns as it is.

If the determination in S10 is NO, the process proceeds to S19 and the flag F is set to 4
That is, it is determined whether or not the previous transition was a transition from the low flow rate side to the high flow rate side of the Q4-R4 line.

If YES in S19, it is checked in S20 whether this time Q is larger than Q6, and if NO, it is next checked in S21 whether this time R is larger than R6. If YES is determined in either S20 or S21, the process proceeds to S22, where the flag F is set to 6, and in S23, the intake cut valve is controlled to be opened (the actuator is connected to the differential pressure detection valve side).

If NO in S21, the process goes to S24 to determine whether Q is smaller than Q3. If YES, it is determined in S25 whether R is smaller than R3. And if S25 is YES,
The flow proceeds to S26, where the flag F is set to 3, and in S27, the exhaust cut valve is controlled to be closed (atmosphere is introduced into the actuator).

If the determination in S19 is NO, F = 6, that is, the previous shift is from the low flow rate side to the high flow rate side of the Q6-R6 line, and in this case, go to S28. It is determined whether Q is smaller than Q5 this time, and if YES, then, in S29, it is determined whether R this time is smaller than R5. If YES, go to S30 and set flag F to 5
, And control to close the intake cut valve in S31 (introduce negative pressure to the actuator). Also, S28 or S29
If NO in any of the above, the process returns as it is.

Next, the flow when the determination in S9 is NO will be described with reference to FIG.

If NO in S9, the process goes to S41 to determine whether or not the flag F is 3, that is, whether or not the previous transition was from the high flow side to the low flow side of the Q3-R3 line. If YES, then it is determined in S42 whether or not the current Q is smaller than Q1, and if YES, it is determined in S43 whether or not R this time is smaller than R1. And if YES, S44
To set the flag F to 1, and then control to open the exhaust cut valve in S45.

If NO in either S42 or S43, go to S46, see if Q is greater than Q4, if NO, go to S4
At 7, it is determined whether R is greater than R4. And S46
Alternatively, if YES in any of S47, the flow proceeds to S48 to set the flag F to 4, and then in S49, control is performed to open the exhaust cut valve. If NO in S47, the process returns.

If NO in S41, it means that F = 5. In this case, go to S50 to determine whether Q is smaller than Q3. If YES, determine whether R is smaller than R3 in S51. I do. If YES in S51, the flag F is set to 3 in S52, and then control is performed to close the exhaust cut valve in S53.

If NO in either S50 or S51, go to S54 to determine whether Q is larger than Q6. If NO, then check in S55 whether R is larger than R6. If YES in S54 or S55, the process proceeds to S56 to set the flag F to 6, and then in S57, controls to open the intake cut valve.

 If NO in S55, the process returns.

Next, another embodiment of the present invention will be described with reference to FIGS. 6 and 7. FIG.

In this embodiment, as shown in FIG.
The primary supercharging pressure P1 and the secondary supercharging pressure P2 are directly introduced into the actuator 133. The detailed structure of the intake cut valve 132 and the actuator 133 for operating the same is as shown in FIG. 7, and the valve shaft 175 of the butterfly valve type intake cut valve 132 is connected to the diaphragm 177 of the actuator 133 by a rod 176. The first pressure chamber 180 and the second pressure chamber 180 are provided between the casing 178 and the cover 179 on both sides of the diaphragm 177.
Pressure chamber 181 is formed. The rod 176 extends through the first pressure chamber 180, while the second pressure chamber 181 is provided with a spring 182 for urging the diaphragm 177 in a direction to press the rod 176. The primary side supercharging pressure P1 is applied to the casing 178 by the first pressure.
An inlet 183 for introducing the pressure chamber 180 into the cover 17 is formed.
In 9, connect the conduit to the output port of the electromagnetic solenoid type three-way valve 138.
An inlet 184 of the second pressure chamber 181 connected through 137 is formed.

As shown in FIG. 6, one input port of the three-way valve 138 is connected to a negative pressure tank (not shown) as in the previous embodiment via a conduit 147, and the other input port is connected to a conduit 185.
And is directly connected to the upstream side of the intake cut valve 132. Therefore, this three-way valve 138 is
The conduit 137 leading to the second pressure chamber 181 of 33 is connected to the intake cut valve.
When connected to the conduit 185 leading to the upstream 132, the secondary side supercharging pressure P2 is introduced into the second pressure chamber 181 of the actuator 133. A primary-side supercharging pressure P1 is introduced into the first pressure chamber 180 via a conduit 186. When the pressure difference P1-P2 across the intake cut valve 132 decreases in this state, the diaphragm 177 is pushed by the urging force of the spring 182, and the rod 176 moves to open the intake cut valve 132. Also, three-way valve
When the conduit 138 connects the conduit 137 leading to the second pressure chamber 181 to the conduit 147 leading to the negative pressure tank, the negative pressure downstream of the throttle valve stored in the negative pressure tank 148 in the second pressure chamber 181 is reduced. Introduced and thereby the diaphragm 177
Is sucked, and the intake cut valve 132 is forcibly closed.

The configuration and functions of the other parts of this embodiment are the same as those of the first embodiment.
There is no difference from the previous embodiment described with reference to FIGS.
6 and 7, the same reference numerals are given to the same parts as those in the previous embodiment.

(Effect of the Invention) Since the inventions of claims 1 to 5 are configured as described above, in the sequential turbo, the second turbocharger is operated in the low flow rate region where only the first supercharger is operated and in the high flow rate region.
The intake cut valve that opens and closes the intake passage in which the blower of the turbocharger is interposed can be reliably closed and the backflow of pressurized intake air can be prevented.

[Brief description of the drawings]

1 is an overall system diagram of one embodiment of the present invention, FIG. 2 is a cross-sectional view of a differential pressure detecting valve in the embodiment, FIG. 3 is a control characteristic diagram of the embodiment, FIG. 4 and FIG. Fig. 6 is a flow chart for executing the control of the embodiment, Fig. 6 is a main part configuration diagram of another embodiment of the present invention, and Fig. 7 is a structural diagram of the intake cut valve and its actuator in the embodiment. 101 ... engine, 102, 103 ... exhaust passage, 104 ... primary turbocharger, 106 ... secondary turbocharger, 110 ... first branch passage, 112 ... second branch passage,
121 ... air flow meter, 122 ... communicating passage, 123 ... exhaust cut valve, 132 ... intake cut valve, 133 ... actuator, 138 ... three-way valve, 146 ... control unit,
148 …… Negative pressure tank.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-169630 (JP, A) JP-A-60-259722 (JP, A) Fully open Showa 63-60023 (JP, U) Really open show 60- 178329 (JP, U)

Claims (5)

(57) [Claims] 1. An engine with a supercharger in which at least a first supercharger operated in a low flow rate region of an intake air amount and a second supercharger operated in a high flow rate region are arranged in parallel. A first intake passage in which a first supercharger is provided; a second intake passage in which the second supercharger is provided; A differential pressure type intake cutoff valve that is disposed downstream and detects opening and closing pressures at upstream and downstream of the location, operating state detecting means for detecting an operating state of the engine, and receives an output of the operating state detecting means. Switching control means for opening the intake cut valve in a high flow rate region to switch the second supercharger from a non-operation state to an operation state, and receiving an output of the operation state detection means, Forcibly closes the intake cut valve regardless of the upstream and downstream differential pressure Control device for an engine with a supercharger, characterized in that a control means for. 2. The supercharger according to claim 1, wherein the control means is configured to close the intake cut valve by an intake negative pressure downstream of the throttle valve in a low flow rate region in which only the first supercharger is operated. Control device for engine with a charger. 3. The control device for a supercharged engine according to claim 2, wherein the intake negative pressure downstream of the throttle valve is accumulated in a predetermined volume chamber. 4. The control device for a supercharged engine according to claim 1, wherein the control means is a control valve for controlling the introduction of pressure to an actuator for controlling the operation of the intake cut valve. 5. An exhaust turbo-type first supercharger operating at least in a low flow rate region of an intake air amount and a second exhaust turbo type supercharger operating in a high flow rate range are arranged in parallel. In the supercharged engine, a first exhaust passage in which a turbine of the first supercharger is provided, a second exhaust passage in which a turbine of the second supercharger is provided, A communication passage that communicates a first exhaust passage upstream of the supercharger with a second exhaust passage upstream of the second supercharger, an exhaust cut valve that opens and closes a second exhaust passage downstream of the communication passage, A first intake passage in which a blower of the first supercharger is interposed; a second intake passage in which a blower of the second supercharger is interposed; and a second intake passage of the second intake passage. A differential pressure type intake cut valve that is located downstream of the turbocharger and that detects the pressure state upstream and downstream of the Operating state detecting means for detecting an operating state of the engine; receiving an output of the operating state detecting means, and opening the exhaust cut valve and the intake cut valve in a high flow rate region to move the second supercharger from an inoperative state. Switching control means for switching to an operating state, and control means for receiving an output of the operating state detecting means and forcibly closing the intake cut valve in a low flow rate region irrespective of the differential pressure upstream and downstream of the intake cut valve. A control device for a supercharged engine.