JPH02191816A - Control device for engine with supercharger - Google Patents

Abstract

PURPOSE:To prevent the lower of the supercharge pressure by opening an exhaust cut valve and an intake cut valve in the high flow quantity area, and changing the switching term to delay the switching at the acceleration time so as to switch the second supercharger to the operated condition. CONSTITUTION:When an operated condition detecting means detects that an engine reaches the high flow quantity area, a switching control means opens an exhaust cut valve and an intake cut valve to operate the second supercharger. At this stage, a relief valve control means opens an intake relief valve to give the prerotation before the exhaust cut valve is opened. At the acceleration time, a switching term changing means switches when the switching is delayed and the rotation of the second supercharger is raised, that is, when the discharge side pressure is raised. Thereby, the lower of the supercharge pressure can be prevented when a turbosupercharger (the second supercharger) to be operated in the high flow quantity area (at the acceleration time) is switched to the operated condition.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) 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, for example, Japanese Patent Application Laid-Open No. 60-259722, two superchargers, a primary and a secondary supercharger, are installed in parallel in an engine, and the turbo supercharger on the secondary side is connected to the turbine inlet side. By opening and closing these cut valves, supercharging is performed only by the primary turbo supercharger in the low flow region, and secondary turbo supercharger is provided in the high flow region. Engines called twin-turbo or sequential turbo engines that operate a turbocharger on the side are known.

By the way, in controlling the turbocharger in this type of engine, when transitioning the secondary turbocharger from an inactive state to an active state, it is necessary to avoid torque shock, etc. due to a delay in the response of the secondary turbocharger. Therefore, prior to switching, it has been conventional practice to run the secondary supercharger, that is, to pre-rotate it. In this case, the pre-rotation of the secondary supercharger is usually performed by opening the exhaust cut valve with the intake relief valve open and allowing exhaust gas to flow to the secondary turbine. However, if the secondary turbine is pre-rotated by opening the exhaust cut valve with the intake relief valve open, a large amount of exhaust gas will already flow to the secondary side when the exhaust cut valve opens. Since the rotation on the primary side will drop if the engine is rotated, the pre-rotation area cannot be made long enough. Therefore,
In such a conventional pre-rotation method, it is difficult to sufficiently increase the rotation speed of the secondary turbocharger before switching to the region where supercharging is performed by the secondary turbocharger, and therefore Torque shock could not be reliably prevented.

Therefore, the present applicant decided to pre-rotate the secondary exhaust turbo supercharger by leaking part of the exhaust gas to this supercharger prior to switching to the operating state,
Therefore, we have previously proposed an intake relief valve that releases the pressure upstream of the intake cut valve so that it closes before the exhaust cut valve opens. According to this, it is possible to secure a sufficient pre-rotation area for the secondary turbocharger, so that it is possible to sufficiently increase the rotation of the secondary turbocharger at the time of switching and prevent torque shock.

In this way, before opening the exhaust cut valve, the pre-rotation of the secondary turbo supercharger is finished, and after the intake relief valve is closed, the exhaust cut valve is opened, and then the intake cut valve is opened again to perform switching. When configuring a control device to perform this, it is necessary to set the switching timing so that fluctuations in boost pressure due to this switching are as small as possible. The best timing will be set accordingly.

However, if the switching timing is set according to steady state conditions, in the case of sudden acceleration, the start of rotation of the primary side and the secondary side will be delayed due to so-called turbo lag, and in particular, the secondary side turbocharger Adding the fact that there is not enough time for the rotation, the lack of rotation at the time of switching becomes even more obvious, and the time from when the intake relief valve closes to when the exhaust cut valve opens becomes shorter, resulting in less pressure rise. Since this is no longer sufficient, a problem arises in that the supercharging pressure drops with the switching.

(Object of the Invention) The present invention has been made in view of the above-mentioned problems, and the present invention has been made in view of the above-mentioned problems. An object of the present invention is to obtain a control device for a supercharged engine that can prevent a decrease in the engine speed.

(Structure of the Invention) The present invention is based on the discovery that the above-mentioned drop in supercharging pressure can be prevented by delaying the switching of the high-flow side supercharger to the operating state during acceleration. As shown in Fig. 1, a first supercharger that operates at least in a low flow rate region of the intake air amount and a second turbocharger of exhaust turbo type that operates in a high flow rate region are arranged in parallel. In the installed supercharged engine, an exhaust cut valve opens and closes an exhaust passage in which a turbine of the second supercharger is disposed, and an intake passage in which a blower of the second supercharger is disposed. An intake cut valve that opens and closes, an operating state detection means that detects the operating state of the engine, and an output of the operating state detection means that opens the exhaust cut valve and the intake cut valve in a high flow rate region to prevent the second overflow. A switching control means for switching the charger from an inoperative state to an operating state, and a switching condition changing means for changing the setting of a switching condition so as to delay switching of the second supercharger from an inactive state to an operating state during acceleration. It has a configuration that includes.

In addition, in those equipped with an intake relief valve that releases pressure on the upstream side of the intake cut valve, and pre-rotating the high-flow side supercharger with this intake relief valve open prior to switching, when accelerating, it is necessary to It is effective to increase the pressure on the discharge side of the supercharger on the high flow rate side.
As shown in FIG. 2, it is preferable to change the settings of the switching conditions so as to delay the switching of the second supercharger from the inactive state to the active state during acceleration, regardless of the intake relief valve.

(Operation) When the engine reaches a predetermined high flow rate region, the exhaust cut valve and the intake cut valve are opened, and the second supercharger on the high flow rate side is activated. In this case, before the exhaust cut valve opens, the second supercharger is pre-rotated by a small amount of exhaust gas leaked to the turbine of the second supercharger while the intake relief valve is open. do. This pre-rotation continues until the intake relief valve closes, and when the rotation is sufficiently increased, the exhaust cut valve and the intake cut valve open and the second supercharger is activated. Further, during acceleration, the switching of the second supercharger from the inactive state to the active state is delayed. Therefore, during acceleration, switching can be performed when the rotation of the second supercharger becomes high, and therefore, it is possible to prevent the supercharging pressure from decreasing at the time of switching.

Furthermore, by delaying the switching of the second supercharger from the inactive state to the operating state during acceleration, independent of the intake relief valve, the discharge side pressure of the second supercharger is increased before switching during acceleration. This more effectively prevents the boost pressure from decreasing.

(Example) Examples will be described below based on the drawings.

FIG. 3 is an overall system diagram of an embodiment of the present invention.

In this embodiment, the engine 101 is a reciprocating two-cylinder engine, and exhaust passages 202 and 203 are provided independently for each cylinder. A turbine 105 of a primary turbocharger 104 is disposed in one of the two exhaust passages 202 and 203, and a turbine 107 of a secondary turbocharger 106 is disposed in the other. Two exhaust passages 102.10
3 merge into one line downstream of both turbines 105 and 107, and are connected to a silencer (not shown).

Further, the intake passage 109 is divided into two downstream of an air cleaner (not shown), and the blower 111 of the primary turbo supercharger 104 is located in the middle of the first branch passage IIO, and the blower 111 of the primary turbo supercharger 104 is located in the middle of the second branch passage 112. A blower 113 of the secondary turbocharger 107 is installed. These branch passages 110° and 112 are formed so as to face each other at the branch part and to extend substantially straight on both sides. Also,
The two branch passages 110 and 112 are connected to each blower 111113.
They rejoin downstream. Then, an intercooler 114 is disposed in the intake passage 109, which has become one again, and a surge tank +15 is disposed downstream of the intercooler 114, and a throttle valve +16 is disposed between the intercooler 114 and the surge tank 115. It is set up. Further, the downstream end of the intake passage 109 branches into two independent intake passages 117 and 118 corresponding to each cylinder of the engine 101, and is connected to each intake port (not shown). These independent intake passages 117 and 118 have fuel injection valves 119 and 1, respectively.
20 are arranged.

On the upstream side of the intake passage 109, the first and second branch passages +10. ! An air flow meter 121 is provided upstream of the branch section 12 to detect the amount of intake air.

The two exhaust passages 102, 103 are communicated with each other by a relatively small diameter communication passage 122 upstream of both the primary and secondary turbochargers 104, 105. In the exhaust passage 103 in which the secondary turbine 107 is disposed, an exhaust cut valve 123 is provided immediately downstream of the opening position of the communication passage +22. Further, a bypass passage 125 is formed which extends from the middle of the communication passage +22 and communicates with the combined exhaust passage 124 downstream of the turbine 105 and 107. 25 is provided with a wastegate valve 127 linked to a diaphragm type actuator +26. An exhaust passage 10 is connected to the upstream portion of the waste gate valve 127 of the bypass passage +25 and the secondary turbine 107.
A leak passage 128 is formed which communicates with the downstream of the exhaust cut valve 123 of No. 3, and an exhaust leak valve 130 linked to a diaphragm type actuator 129 is provided in the leak passage 128.

Exhaust cut valve! 23 is linked and connected to a diaphragm type actuator 131. On the other hand, the branch passage 1 in which the blower 113 of the secondary turbocharger 106 is disposed
12, an intake cut valve 132 is disposed downstream of the blower 113. This intake cut valve 132 is composed of a butterfly valve, and is also a diaphragm type actuator 1.
33. In addition, a relief passage +34 is formed in the branch passage 112 on the secondary side so as to bypass the blower 113.
34 is provided with a diaphragm type intake relief valve 135.

The actuator 12 that operates the exhaust leak valve 130
The pressure chamber 9 is connected via a conduit 136 to a branch passage +1 in which the blower 111 of the primary turbocharger 104 is disposed.
It is connected to the downstream side of the blower 113 of No. 0. When the pressure downstream of this blower 113 exceeds a predetermined value, the actuator 129 is operated to open the exhaust leakage valve 130, thereby allowing a small amount of exhaust gas to pass through the bypass passage 128 when the exhaust cut valve 123 is closed. It flows and is supplied to the secondary turbine 107. Therefore, the secondary turbo supercharger 106 starts rotating in advance before the exhaust cut valve +23 opens. During this time, since the intake relief valve is opened as will be described later, the rotation of the secondary turbo supercharger 106 increases, the transient response when the exhaust cut valve opens is improved, and the torque shock is alleviated.

The actuator 13 that operates the intake cut valve 132
The pressure chamber No. 3 is connected to an output port of an electromagnetic solenoid type three-way valve 138 by a conduit 137. Further, the actuator 131 that operates the exhaust cut valve 123 is
Another three-way valve 140 of electromagnetic solenoid type is connected by conduit 139.
connected to the output port of the Furthermore, the pressure chamber of the actuator 141 that operates the intake relief valve 135 is
Another three-way valve 143 of electromagnetic solenoid type is connected by conduit 142.
connected to the output port of the Intake relief valve 135
As will be described later, the relief passage 13 is closed until a predetermined time before the exhaust cut valve I23 and the intake cut valve 132 open.
Leave 4 open. And as a result, leakage passage +2
Secondary turbo supercharger 1 by exhaust gas flowing through 8
During the pre-rotation of 06, the pressure upstream of the intake cut valve +32 is prevented from rising and entering the surging region, and the rotation of the blower 113 is increased.

The actuator 126 operating the wastegate valve 127 is connected by a conduit 144 to the output port of another three-way valve 145 of the electromagnetic solenoid type.

The above four electromagnetic solenoid type three-way valves 138, 140.1
43 and 145 are controlled by a control unit 146 configured using a microcomputer. The control unit 146 has an engine speed R1.
In addition to the intake air flQ, the throttle opening TVO, the boost pressure Pl downstream of the primary side blower 111, etc. are input, and the control described below is performed based on these.

One input port of the electromagnetic solenoid three-way valve 138 for controlling the intake cut valve 132 is connected to the negative pressure tank 148 via a conduit 147, and the other input port is connected to the conduit 1.
49 to the output port 17 of the differential pressure detection valve 150, which will be described later.
Connected to 0.

Intake negative pressure downstream of the throttle valve l16 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 is open to the atmosphere, and the other human-powered boat is
It is connected via a conduit 152 to the conduit 147 which is connected to the negative pressure tank 148 . On the other hand, one input port of a 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 connected downstream of the throttle valve 116 via a conduit 153. Further, 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 primary blower l11 through a conduit 154. has been done.

As shown in FIG. 4, the differential pressure detection valve 150 has three chambers 164, 165, 1 formed by two diaphragms 162, 163, a first and a second diaphragm.
It is divided into 66 sections. A first input port 167 is opened in the first chamber 164 at one end, and the inner surface of the end of the casing 161 and the first diaphragm 16
A compression spring +68 is disposed between the two. In addition, the second chamber +65 in the middle has a second input port 169.
In the third chamber 166 on the other end side, an output port 170 is opened in the center of the end wall of the casing 161, and an atmosphere release boat 171 is opened in the side wall. The first diaphragm 162 includes a second diaphragm 16.
A valve body I72 is fixedly provided, passing through the third chamber 166 and extending toward the output port 170 of the third chamber 166.

The first input port 167 is connected by a conduit 173 to a third
As shown in the figure, it is connected to the downstream side of the intake cut valve 132, and introduces the supercharging pressure P1 downstream of the primary side blower 111 into the above-mentioned second chamber 164.

The second input port 169 is also connected upstream of the intake cut valve 132 by a conduit 174, so that the second input port 169 is connected upstream of the intake cut valve 132 when the intake cut valve 132 is closed.
The upstream pressure P2 is introduced. The pressures PI, P introduced from this two-man powered boat 167.169
When the difference between the two is greater than or equal to a predetermined value, the valve body 172 opens the output port 170. This output port +70 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, 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 differential pressure detection valve 15.
When the differential pressure P2-PI becomes larger than a predetermined value while communicating with the conduit +49 connected to the output port 0, the atmosphere is introduced into the actuator 133 and the intake cut valve 132 is opened. In addition, a three-way valve 138 connects the conduit 137 on the actuator 133 side to the negative pressure tank 14.
When connected to the conduit 147 connected to B, negative pressure is supplied to the actuator 133, and the intake cut valve 13
2 or closed.

On the other hand, in the exhaust cut valve 123, when the three-way valve 140 for controlling the exhaust cut valve 123 connects the conduit 139 connected to the pressure chamber of the actuator 131 for operating the exhaust cut valve 123 to the conduit 152 on the negative pressure tank 148 side, It is closed by supplying negative pressure to the actuator. Also, when the three-way valve 140 releases the output side conduit 139 to the atmosphere, an exhaust cut valve is activated! 23 is opened, and supercharging by the secondary turbo supercharger 106 is performed.

FIG. 5 shows the intake cut valve 132. Exhaust cut valve I23.
This is a control map showing the open/close states of the intake relief valve 135 and the waste gate valve 127, as well as the open/close states of the exhaust leak valve +30. This map is stored in the control unit 146, and based on this map, the four electromagnetic solenoid type three-way valves 138, 140, 143, 1
45 controls are performed.

In a region where the engine speed R is low or the intake air amount Q is small, the intake relief 135 is open, and the exhaust leak valve 130 is opened to pre-rotate the secondary turbocharger 106. When the engine speed reaches R2 or the intake air amount reaches Q2, the intake relief valve 135 is closed, and the pressure downstream of the secondary blower 113 increases until the exhaust cut valve +23 opens. When the line Q4-R4 is reached, the exhaust caputo valve 123 opens, and then the Q4-R4 line is reached.
When the 6-R6 line is reached and the intake cut valve 132 is opened, supercharging by the secondary turbo supercharger 106 begins, and the supercharging region by both the primary and secondary superchargers begins at the Q6-46 line.

Intake cut valve 132. The exhaust cut valve 123 and the intake relief valve 135 have a slight hysteresis from the high flow rate side to the low flow rate side, that is, the Q shown by the broken line in FIG.
It is switched on each line of 5-R5, Q3-R3, and Ql-RI.

Note that the bent portions of each of these lines are on the 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 greater than a predetermined value and the boost pressure PI downstream of the primary side blower is greater than a predetermined value.

Furthermore, during acceleration, as shown in FIG. 6, the timing of opening the exhaust cut valve 123 and the intake cut valve 132 compared to the steady state is adjusted to the high flow rate and high rotation side, thereby controlling the operation of the secondary turbo supercharger 106. Switching to supercharging region is delayed.

However, the closing timing of the intake relief valve +35 will not be changed.

FIG. 7 is a characteristic diagram showing the supercharging characteristics obtained by the control of this embodiment in comparison with the case where the switching timing is not changed as described above during acceleration. Here, the solid line indicates the characteristics of the rotational speed of the primary turbocharger and the secondary turbocharger during steady state, and the characteristics of the supercharging pressure accordingly. The dashed line indicates the characteristic when the switching timing is delayed during acceleration as described above, and the broken line indicates the characteristic when such control during acceleration is not performed. As shown in this figure, if the switching timing is not delayed during acceleration,
A delay in the startup of rotation of both superchargers due to turbo lag and a lack of pre-rotation on the secondary side combine to cause a drop in supercharging pressure at the time of switching. On the other hand, when the acceleration control described above in this embodiment is performed, the rotation on the primary side increases, the rotation on the secondary side also increases, and switching is performed with the discharge side pressure increasing. , no drop in boost pressure occurs.

Figures 8 and 9 show the intake cut valve in this embodiment! 23. Exhaust cut valve 132 and intake relief valve 1
35 is a flowchart for executing the above control of No. 35. Note that S indicates each step.

Further, F is a flag, and the state of this flag (F-1
The meanings of ~6) are as shown in FIG. 5, where the previous transition was a transition from the high flow rate side to the low flow rate side of the Ql-R1 line (P = 1), respectively.
This is the transition from the low flow rate side to the high flow rate side of the Q2-R2 line (F = 2), the transition from the high flow rate side to the low flow rate side of the Q3-113 line (P = 3), and the Q4-R4 line is the transition from the low flow rate side to the high flow rate side (F = 4.), Q5
- This is the transition from the high flow rate side to the low flow rate side of the R5 line (
F=5), and transition from the low flow rate side to the high flow rate side of the Q6-R6 line (F=6). The steps will be explained below.

First, in FIG. 8, the system starts and initialization is performed at Sl. At this time, the flag is set to 1.

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

Next, in S4, the rate of change dQ/d[
Acceleration is determined based on whether or not is greater than a predetermined value A.

If dQ/dt>A, that is, during acceleration, then go to S5 and set Q4. corresponding to the opening timing of the exhaust cut valve 123 and the intake cut valve +32. Q6. R4
, R6 are set to predetermined values ΔQ4. ΔQ6. ΔR4, ΔR
Increase correction by 6.

It does nothing unless it is during acceleration. Then go to 86.

In S6, it is checked whether the flag F is 1, that is, whether the previous transition was from the high flow rate ff1l to the low flow rate side of the Ql-R1 line. Note that initially F=
1, and therefore, this determination is YES.

If F=1, then go to S7 to determine whether Q is larger than Q2 this time, and if No,
Next, in S8, it is checked whether R is larger than R2 this time. If YES in S7 or YES in S8, the process goes to S9, sets the flag F to 2, and controls the SIO to close the intake relief valve (introduces positive pressure to the actuator). Further, if the determinations in S7 and S8 are both NO, the process directly returns.

If the determination in S6 is No, go to S11 and check whether the flag F is an even number, that is, whether the previous transition occurred on any line from the low flow rate side to the high flow rate side. I see.

Then, if YES in Sll, go to SI2 and F=
2, that is, whether the previous transition was from the low flow rate side to the high flow rate side of the Q2-R2 line. If F=2, the process goes to S13.

In S13, it is determined whether Q is greater than Q4 this time, and if NO, then in S14 it is determined whether R is greater than R4 this time. If either S+3 or SI4 is YES, the process goes to S+5 and sets the flag F to 4, and in S16 the exhaust cut valve is controlled to open (negative pressure is introduced to the actuator).

Further, when both the determinations in S13 and SI4 are NO, the process goes to S17 to see if the current Qh<Ql rise is small.

If YES in S17, it is checked in S+8 whether R is smaller than R1 this time. And if YES, S19
Go to , set flag F to 1, and control the intake relief valve to open in S20 (introduce negative pressure to the actuator). Also, if the judgments in S17 and 81B are both NO, return directly. .

If the determination in S12 is NO, go to S21 and check whether the flag F is 4, that is, if the previous transition was Q4-R.
It is determined whether there has been a transition from the low flow rate side to the high flow rate side of the 4th line.

If YES in S21, it is checked in S22 whether Q is larger than Q6 this time, and if it is NO, then it is checked in S23 whether R is larger than R6 this time. And S2
If YES in either S2 or S23, S24
, and sets the flag F to 6, and in S25 controls the intake cut valve to be opened (the actuator is communicated with the differential pressure detection valve side).

Also, if NO in S23, go to S26 and Q is Q3.
Determine whether it is smaller than the value, and if YES, S27
It is determined whether R is smaller than R3. And S
If YES in 27, go to 828 and set the flag F to 3, and control the exhaust cut valve to close in S29 (
(introducing atmospheric air into the actuator).

If the judgment in S21 is NO, it means that F=6, that is, the previous transition was from the low flow rate side to the high flow rate side of the Q6-R6 line, and in this case, go to S30 and change the current flow rate. It is determined whether Q is smaller than Q5, and if YES, it is then determined in S31 whether or not R is smaller than R5 this time. If YES, go to S32, set flag F to 5, and control to close the intake cut valve in 933 (introduce negative pressure to the actuator).
,ll Also, NO in either S30 or S31
In this case, return as is.

Next, the flow when the SZ determination is No will be explained with reference to FIG.

If No in Sll, the process goes to S41 to determine whether flag F is 3, that is, whether the previous transition was from the high flow rate side to the low flow rate side of the Ql-R3 line. If YES, then in S42 it is determined whether Q is smaller than Ql this time, and if YES, S42 is performed.
In step 43, it is determined whether R is smaller than R1 this time. If YES, the process goes to S44 to set flag F to 1, and then, in S45, control is performed to open the exhaust gas cut valve.

If NO in either S42 or S43, S4
Go to 6, check whether Qh<Q4, and answer No.
If so, it is determined in S47 whether Rh<R4. Then, in either S46 or S47, Y
If it is ES, go to S48 and set flag F to 4,
Next, in S49, the exhaust cut valve is controlled to open. Further, if the answer is No in S47, the process returns directly.

If No in S41, it means that P=5, and in this case, go to S50 and determine whether it is smaller than lQ3. If YES, go to S51 and determine whether Rh<R3. If YES in S51, the flag F is set to 3 in S52, and then the exhaust cut valve is controlled to be closed in S53.

If NO in either S50 or S51, S5
Go to 4 and determine whether Q is greater than Q6, NO
If so, then it is checked in S55 whether R is greater than R6. If YES in either S54 or S55, the process goes to 956 to set flag F to 6, and then, in S57, control is performed to open the intake cut valve.

Further, if NO in S55, the process returns directly.

In the above embodiment, during acceleration, the closing timing of the intake relief valve remains the same and the opening timings of the exhaust caputo valve and the intake cut valve are shifted, but the closing timing of the intake relief valve is also shifted at the same time. It is also possible to do so.

The present invention can be implemented in various other ways.

(Effects of the Invention) Since the present invention is configured as described above, during acceleration, when switching to the operating state of the turbocharger operated in a high flow rate region, the supercharging pressure due to turbo lag and insufficient pre-rotation is reduced. It is possible to prevent a drop in the flow rate and realize a smooth transition to a high flow area.

Additionally, during acceleration, by opening the exhaust cut valve and intake cut valve independently of the intake relief valve, the switching to the high-flow side supercharger operating state is delayed, thereby more effectively controlling the supercharging pressure at the time of switching. The decline can be prevented.

[Brief explanation of the drawing]

1 and 2 are overall configuration diagrams of the present invention, FIG. 3 is an overall system diagram of an embodiment of the present invention, FIG. 4 is a sectional view of a differential pressure detection valve in the same embodiment, and FIGS. FIG. 6 is a control characteristic diagram of the same embodiment, FIG. 7 is a characteristic diagram showing the effects of the same embodiment, and FIGS. 8 and 9 are flowcharts for executing the control of the same embodiment. 101: Engine, 104 niblimari turbo supercharger,
+06・Secondary turbo supercharger, 123; Exhaust cut valve, 131, 133, 141: Actuator, ■32
; Intake cut valve, 134 Correct relief passage, 135: Intake relief valve, 138140.143: Electromagnetic solenoid type three-way valve, 146: Control unit. Agent Patent Attorney Jun Shinfuji - Fig. Fig. 4 Fig. No. 2 - To H.
Figure 1) Exhaust force/I monument

Claims (2)

[Claims] (1) In a supercharged engine in which at least a first supercharger that operates in a low flow rate region of intake air amount and a second turbocharger of exhaust turbo type that operates in a high flow rate region are arranged in parallel. , an exhaust cut valve that opens and closes an exhaust passage in which a turbine of the second supercharger is disposed; an intake cut valve that opens and closes an intake passage in which a blower of the second supercharger is disposed; and an engine. operating state detecting means for detecting the operating state of the engine; and operating state detecting means for operating the second supercharger from an inactive state by opening the exhaust cut valve and the intake cut valve in a high flow region in response to the output of the operating state detecting means. and switching condition changing means for changing the setting of the switching condition so as to delay the switching of the second supercharger from the inactive state to the active state during acceleration. Control device for supercharged engines. (2) In a supercharged engine in which at least a first supercharger that operates in a low flow rate region of intake air amount and a second turbocharger of an exhaust turbo type that operates in a high flow rate region are arranged in parallel. , an exhaust cut valve that opens and closes an exhaust passage in which a turbine of the second supercharger is disposed; an intake cut valve that opens and closes an intake passage in which a blower of the second supercharger is disposed; an intake relief valve that releases pressure on the upstream side of the intake cut valve; an operating state detection means that detects the operating state of the engine; switching control means that opens to switch the second supercharger from an inactive state to an active state; and relief valve control means that closes the intake relief valve at the same time as or before the exhaust cut valve opens; The present invention is characterized by further comprising switching condition changing means for changing the setting of switching conditions so as to delay switching of the second supercharger from an inactive state to an active state during acceleration, regardless of the intake relief valve. Control device for supercharged engines.