JPH03105020A - Controller for engine equipped with supercharger - Google Patents

Abstract

PURPOSE:To improve the reliability when an intake cut valve is in trouble, by installing a detecting means for detecting the operation state of the intake cut valve on the secondary supercharger side and prohibiting the operation of the supercharger when the intake cut valve is in closed state in a specific operation region. CONSTITUTION:Exhaust passages 202 and 203 in which the turbines 205 and 207 of the primary and secondary turbosuperchargers 204 and 206 are arranged are allowed to communicate through a communication passage 222 on the upstream of superchargers 204 and 206, and an exhaust cut valve 223 is installed on the exhaust passage 203 side. Further, in a branched passage 212 in which the blower 213 of the secondary supercharger 206 is arranged, an intake cut valve 232 is arranged, and a position sensor 256 is installed onto an actuator 233 for driving the intake cur valve 232. The intake cut valve 232 is in closed state except in a specific operation region, and the operation state is detected by the sensor 256. When it is detected that the intake cut valve 232 in a closed state in the specific operation region, the operation of the supercharger 206 is prohibited.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a supercharged engine that is equipped with a plurality of superchargers and that operates some of the exhaust turbo superchargers only in a specific operating range. The present invention relates to a control device.

(Prior Art) Conventionally, as a turbocharged engine equipped with two exhaust turbochargers, a primary exhaust turbo and a secondary exhaust turbo are installed in the exhaust passage, for example, as disclosed in Japanese Utility Model Application Publication No. 60-178329. The turbocharger turbines are installed in parallel, the blowers of these two exhaust turbosuperchargers are connected to the intake passage of the engine, and an exhaust cut valve is installed in the exhaust passage upstream of the turbine of the secondary turbocharger. In the low intake air amount range where the intake air amount is less than the set value, the exhaust cut valve is closed and the secondary turbo supercharger is deactivated.
Exhaust gas from the exhaust passage is intensively supplied to the turbine of the brimary turbo supercharger to ensure high boost pressure.
In the high intake air amount range where the intake air amount is higher than the set value, the exhaust cut valve is opened and the secondary turbo supercharger is activated.
BACKGROUND ART Sequential turbo engines are known in which exhaust gas from an exhaust passage is supplied to the turbines of two exhaust turbo superchargers to obtain an appropriate boost pressure while securing an intake air amount.

(Problem to be solved by the invention) In such a supercharged engine, an intake cut valve is provided in the intake passage dedicated to the secondary turbo supercharger, and the intake air amount range is low in which the secondary turbo supercharger is inactive. This intake cut valve is then closed to prevent the pressurized air downstream of the primary blower from flowing back into the secondary blower.

However, if this intake cut valve fails and remains closed, and the exhaust cut valve opens in a high intake air volume region, the intake passage downstream of the secondary side blower is blocked by the intake cut valve, and the secondary blower opens. Since the side blower rotates, this secondary side blower causes surging, which impairs the reliability of the secondary turbo supercharger.

The present invention has been made with attention to these points,
The purpose of this is to deactivate the secondary turbocharger to avoid surging of the secondary blower when the intake cut valve fails.

(Means for Solving the Problems) In order to achieve the above object, the present invention prohibits the operation of the secondary turbocharger when the intake cut valve is closed in a specific operating range in which the secondary turbocharger operates. That's what I do.

Specifically, the solution taken by the present invention is to arrange a plurality of superchargers including an exhaust turbo supercharger in parallel in the intake passage, and at least one of the exhaust turbo superchargers is connected to a secondary turbo supercharger. The assumption is that the engine is equipped with a supercharger and a secondary turbo supercharger is operated only in a specific operating range. In contrast, an intake cut valve that closes outside the specific operating range is provided in the intake passage dedicated to the secondary turbocharger, and an operating state detection means for detecting the operating state of the intake cut valve, and the operating state detection means The turbocharger control means receives the output of the turbocharger and prohibits the operation of the secondary turbocharger when the intake cut valve is closed in a specific operating range.

(Function) With the above structure, in the present invention, the operation of the secondary turbocharger is prohibited when the intake cut valve is closed in a specific operating range by the supercharger control means based on the detection by the operating state detection means. Therefore, even if the intake cut valve fails and remains closed, the secondary blower will not cause surging, improving the reliability of the secondary turbo supercharger.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows a two-rotor type turbocharged rotary piston engine equipped with a control device according to an embodiment of the present invention. In FIG. 1, 201 is an engine, and exhaust passages 202 and 203 are provided independently of each other. And these two exhaust passages 202, 20
3, the turbine 205 of the primary turbo supercharger 204 is placed on one side, and the secondary turbo supercharger 20 is placed on the other side.
6 turbines 207 are respectively arranged.

That is, in this engine 201, each exhaust passage 202, 203 is independently connected to the turbine 205 of both the primary and secondary exhaust turbo superchargers 204, 206.
, 207, both exhaust turbo superchargers 204
, 206, the exhaust dynamic pressure is effectively applied to both turbines 205 and 207 in the region where supercharging is performed, thereby improving supercharging efficiency. Two exhaust passages 202, 203
are joined downstream of both turbines 205 and 207 to form a single exhaust passage 224.

Further, the intake passage 209 is divided into two downstream of an air cleaner (not shown), and the blower 211 of the hybrid turbo supercharger 204 is located in the middle of the first branch passage 210, and the blower 211 of the hybrid turbo supercharger 204 is located in the middle of the second branch passage 212. A blower 213 of the secondary turbo supercharger 206 is disposed in the . These branch passages 210 and 212 are shaped so as to face each other at the branch part and extend substantially in a straight line on both sides. Also,
The two branch passages 210 and 212 are connected to each blower 211 and 21.
It rejoins downstream of 3. Then, an intercooler 214 is disposed in the intake passage 209, which has become one again, and a surge tank 215 is disposed downstream of the intercooler 214, and a throttle valve 216 is disposed between the intercooler 214 and the surge tank 215. It is set up. Further, the downstream end of the intake passage 209 branches into two independent intake passages 217 and 218 corresponding to each cylinder of the engine 201, and is connected to each intake port (not shown). Each of these independent intake passages 217 and 218 has a fuel injection valve 219.
220 are arranged.

On the upstream side of the intake passage 209, an air flow meter 221 is provided upstream of the branch of the first and second branch passages 210 and 212 to detect the amount of intake air.

The two exhaust passages 202, 203 are communicated with each other by a relatively small diameter communication passage 222 upstream of both the primary and secondary turbo superchargers 204, 206. In the exhaust passage 203 in which the secondary turbine 207 is disposed, an exhaust cut valve 223 is provided immediately downstream of the opening position of the communication passage 222.

Further, the turbine 20 extends from the middle of the communication path 222.
A waste gate passage 225 is formed which communicates with a confluence exhaust passage 224 downstream of 5,207, and a waste gate valve 227 to which a diaphragm type actuator 226 is linked is disposed in the waste gate passage 225.

A leakage passage 228 is provided that communicates the wastegate valve upstream part of the wastegate passage 225 with the exhaust cut valve downstream part of the exhaust passage 203 connected to the secondary turbine 207. The exhaust leak passage 22
8 is provided with an exhaust leak valve 230 linked to a diaphragm type actuator 229.

The exhaust cut valve 223 is linked to a diaphragm type actuator 231. This exhaust cut valve 22
3 is set to a so-called normally closed type. In other words, when the engine is not operating, actuator 2
It is configured to close in response to the spring force of the actuator 231, and to open in response to the operating force of the actuator 231, which is turned ON when the engine is operating. As a result, when the exhaust cut valve 223 fails, the secondary turbo supercharger 20
6 can be prevented from flowing into the exhaust gas.

The actuator 231 is provided with a position sensor 255 that detects the opening degree of the exhaust cut valve 223. On the other hand, the blower 2 of the secondary turbo supercharger 206
An intake cut valve 232 is disposed downstream of the blower 213 in the branch passage 2l2 in which the blower 13 is disposed. This intake cut valve 232 is constituted by a butterfly valve, and is also linked to a diaphragm type actuator 233.

This intake cut valve 232 is set to a so-called normally closed type. That is, when the engine is not operating, the actuator 233 is closed by the spring force of the actuator 233, and when the engine is operating, the actuator 23 is turned on.
It is configured to open in response to the actuation force of 3. The actuator 233 is provided with a position sensor 256 that detects the opening degree of the intake cut valve 232.

This position sensor 256 is connected to the intake cut valve 232.
It functions as an operating state detection means for detecting the operating state of. Further, a relief passage 234 is formed in the branch passage 212 on the secondary side so as to bypass the blower 213, and the relief passage 234 is linked to a diaphragm type actuator 241 to connect the intake relief valve 2.
35 are arranged. The relief passage 234 is provided with a first pressure sensor 257 for detecting the pressure of intake air on the upstream side of the intake relief valve 235, and a second pressure sensor 258 for detecting the pressure of pressurized air on the downstream side. It is being

The actuator 22 that operates the exhaust leak valve 230
The pressure chamber 9 is connected via a conduit 236 to a branch passage 21 in which a blower 211 of the primary turbocharger 204 is disposed.
It is connected downstream of the blower 211 of No. 0. When the pressure on the downstream side of this blower 7211 exceeds a predetermined value,
The actuator 229 operates to open the exhaust leak valve 230, thereby allowing a small amount of exhaust gas to flow through the exhaust leak passage 228 and to the secondary turbine 207 when the exhaust cut valve 223 is closed. Therefore, the secondary turbo supercharger 206 starts rotating in advance before the exhaust cut valve 223 opens.

The actuator 23 that operates the intake cut valve 232
The pressure chamber No. 3 is connected to an output port of an electromagnetic solenoid type three-way valve 238 by a conduit 237. Further, the actuator 231 that operates the exhaust cut valve 223 is
Another three-way valve 240 of the electromagnetic solenoid type is connected to the conduit 239.
connected to the output boat. Furthermore, the pressure chamber of the actuator 241 that operates the intake relief valve 235 is
Another three-way valve 243 of electromagnetic solenoid type is connected to the conduit 242.
connected to the output boat. Intake relief valve 235
The relief passage 234 is kept open until a predetermined time before the exhaust cut valve 223 and the intake cut valve 232 open. Thereby, when the secondary turbo supercharger 206 is pre-rotated by the exhaust gas flowing through the exhaust leak passage 228, air is circulated through the blower 213 of the secondary turbo supercharger 206, and the temperature of the blower 213 is prevented from increasing. This prevents the pressure upstream of the intake cut valve 232 from rising and entering the surging region.

The actuator 226 that operates the wastegate valve 227 is connected by a conduit 244 to the output port of another three-way valve 245 of the electromagnetic solenoid type.

The above four electromagnetic solenoid type three-way valves 238, 240
, 243, 245 and two fuel injection valves 219, 22
0 is controlled by a control unit 246 configured using a microcomputer. The control unit 246 includes the output signal of the engine speed sensor, the output signal of the air flow meter 221, the position and
In addition to the output signals of the sensors 255 and 256 and the output signals of the first and second pressure sensors 257 and 258, the throttle opening, the supercharging pressure P1 downstream of the blower 211 on the brimer 9 side, etc. are input.

One manual port of the electromagnetic solenoid type three-way valve 238 for controlling the intake cut valve 232 is connected to a negative pressure tank 248 via a conduit 247, and the other manual port is connected to a negative pressure tank 248 via a conduit 247.
49 to the output boat 27 of the differential pressure detection valve 250, which will be described later.
Connected to 0.

Intake negative pressure downstream of the throttle valve 216 is introduced into the negative pressure tank 248 via a check valve 251 .

Further, one manual boat of the three-way valve 240 for controlling the exhaust cut valve is open to the atmosphere, and the other input boat is connected to the conduit 247 connected to the negative pressure tank 248 via the conduit 252. It is connected.

On the other hand, one manual port of the three-way valve 243 for controlling the intake relief valve 235 is connected to the negative pressure tank 248, and the other manual port is open to the atmosphere. Further, one manual port of the three-way valve 245 for controlling the waste gate valve 227 is open to the atmosphere, and the other manual port is connected to the conduit 236 by a conduit 254.

As shown in FIG. 2, the differential pressure detection valve 250 has three chambers 264, 265, 2 formed by two diaphragms 262, 263, a first and a second diaphragm.
It is divided into 66 sections. A first input boat 267 is opened in the first chamber 264 at one end, and the inner surface of the end of the casing 261 and the first diaphragm 26
A compression spring 268 is disposed between the two. In addition, a second input boat 269 is located in the second chamber 265 in the middle.
In the third chamber 266 on the other end side, an output port 270 is opened in the center of the end wall of the casing 261, and an atmosphere release port 271 is opened in the side wall. The first diaphragm 262 includes a second diaphragm 26.
A valve body 272 is fixedly provided, passing through the third chamber 266 and extending toward the output port 270 of the third chamber 266.

The first input boat 267 is connected by a conduit 273 to the first
As shown in the figure, it is connected to the downstream side of the intake cut valve 232, and introduces the supercharging pressure P1 downstream of the intake blower 211 into the first chamber 264.

The second input port 269 is also connected upstream of the intake cut valve 232 by a conduit 274, so that the second input port 269 is connected upstream of the intake cut valve 232 when the intake cut valve 232 is closed.
The upstream pressure P2 is introduced. Pressures PI and P introduced from both input ports 267 and 269
2 (P2 - PI) exceeds a predetermined value, the valve body 27
2 opens the output boat 270. This output boat 270 is connected via conduit 249 to one of the manpower ports of the three-way valve 238 for controlling the intake cut valve 232. Therefore, when the three-way valve 238 is turned on, the conduit 2 connected to the pressure chamber of the actuator 233 for operating the intake cut valve 232
37 is connected to the conduit 249 connected to the output port of the differential pressure detection valve 250, the intake cut valve 232
When the upstream pressure, that is, the supercharging pressure P2 on the secondary side approaches the supercharging pressure P1 on the primary side, the differential pressure Pi-P2 disappears, and further, when the differential pressure P2-PI becomes larger than a predetermined value, the actuator 233 Atmospheric air is introduced into the air, and the intake cut valve 232 is opened. Also, the three-way valve 238 is OF
When the conduit 237 on the actuator 233 side is connected to the conduit 247 connected to the negative pressure tank 248 at F, negative pressure is supplied to the actuator 233,
Intake cut valve 232 is closed.

On the other hand, the exhaust cut valve 223 is activated when the three-way valve 240 for controlling the exhaust cut valve 223 is OFF and the actuator 231 for operating the exhaust cut valve 223 connects the conduit 239 connected to the pressure chamber to the conduit 252 on the negative pressure tank 248 side. , is closed by supplying negative pressure to the actuator 231.

Further, when the three-way valve 240 is turned on and the conduit 239 on the output side is released to the atmosphere, the exhaust cut valve 223 is opened and supercharging by the secondary turbo supercharger 206 is performed.

The intake relief valve 235 is operated by the actuator 241 when the three-way valve 243 for controlling the intake relief valve 235 is OFF and the conduit 242 connected to the pressure chamber of the actuator 241 for operating the intake relief valve 235 is communicated with the negative pressure tank 248 side. Opens when negative pressure is supplied, and
When the three-way valve 243 is turned on and the conduit 242 connected to the pressure chamber of the actuator 241 is released to the atmosphere, it is closed.

In addition, the actuator 2 for operating the waste gate valve 227
26 is a three-way valve 245 for controlling the waste gate valve 227
When is ON, it communicates with the downstream side of the blower 211 via conduits 254 and 236, and when this three-way valve 245 is OFF, it is released to the atmosphere.

In this embodiment, hysteresis is provided in the opening and closing operations of the exhaust cut valve 223, the intake cut valve 232, and the intake relief valve 235, as will be described later. Also, from high intake air amount area to low intake air. In order to prevent backflow of intake air to the secondary blower when the exhaust cut valve 223 closes and the intake cut valve 232 remains open during the transition to the air volume region, in this region, the time when the exhaust cut valve 223 is closed is set. As a starting point, the intake cut valve 232 is forcibly closed after a predetermined time (for example, 2 seconds) has elapsed.

FIG. 3 shows an intake cut valve 232, an exhaust cut valve 223,
It is a control map showing the opening/closing control of the intake relief valve 235 and the waste gate valve 227 together with the opening/closing control of the exhaust leak valve 230. This map is stored in the control unit 246, and based on this map, the four electromagnetic solenoid type three-way valves 238, 240, 243, 2
45 controls are performed.

When transitioning from a low intake air amount region to a high intake air amount region, in a region where the engine speed R is low or the intake air ffiQ is small, the intake relief valve 235 is open and the exhaust leakage valve 230 is opened. Thus, the secondary turbocharger 206 rotates 1,000 times. Then, when the engine speed reaches R2 or the intake air amount reaches the line Q2, the solenoid type three-way valve 243 for controlling the intake relief valve 235 is turned on and the intake relief valve 235 is closed.

When the Q4-R4 line is reached, the solenoid type three-way valve 240 for controlling the exhaust cut valve 223 is turned ON and the exhaust cut valve 223 is opened, and then the Q6-R6 line is reached, and the solenoid type three-way valve 240 for controlling the exhaust cut valve 223 is turned on. When the solenoid type three-way valve 238 is turned on and the intake cut valve 232 is opened, supercharging by the secondary turbo supercharger 206 starts.

In other words, the engine enters the supercharging region using both the primary and secondary superchargers at the Q6-R6 line.

Note that the actuator 23 that drives the intake cut valve 232
3 is not only controlled by the operation of the solenoid 238, but also because atmospheric pressure, which is the pressure source that opens the intake cut valve 232, is supplied via the differential pressure detection valve 250, the actual operation of the intake cut valve 232 is The opening operation will be delayed relative to the operation of the solenoid 238. Therefore, Q6 above turns the intake cut valve 232 control solenoid 238 from OFF to ON. The R6 line is set in consideration of the delay caused by the differential pressure detection valve 250, and as a result, the Q6 and R6 lines are set so that the exhaust cut valve 223 control solenoid 240 is turned off.
It is assumed that the line is close to the line of Q4 and R4 which turn on from F. Further, these Q6, R6 and Q4, R4 can also be made to match.

Conversely, when transitioning from a high intake air amount region to a low intake air amount region, each solenoid type three-way valve 238, 240, 243 that controls the intake cut valve 232, the exhaust cut valve 223, and the intake relief valve 235 has hysteresis. Third
As shown by broken lines in the figure, Q5-R5. Q3-R3
．． It is set to switch on the Ql-Rl line. In other words, when transitioning from a high intake air amount area to a low intake air amount area, when the line Q3, R3 is reached, the exhaust cut valve 2
The intake cut valve 232 is closed when the closing control of 23 is performed, and when the transition to the low intake air amount region reaches the line Q5 and R5, the intake cut valve 232 is closed.
The intake relief valve 23 is closed after a delay.
5 opening control is performed.

In this way, by closing the intake cut valve 232 later than the exhaust cut valve 223, surging is prevented from occurring when transitioning to the low intake air amount region.

In addition, in this embodiment, the line that turns on and off the solenoid type three-way valve 245 for controlling the waste gate valve 227 is the line that turns on and off the solenoid type three-way valve 245 for controlling the waste gate valve 227.
, Q4-R4 and Q3-R3, which are OFF lines.

In addition, in FIG. 3, the bent portions of each of the above lines are on the so-called no-load line or load-load line.

Therefore, in the above embodiment, when the engine is in a lower intake air amount region than line Q6-R6, the introduction of exhaust gas to the secondary turbo supercharger 206 is stopped, so only the secondary turbo supercharger 204 is operated. When activated, high boost pressure can be obtained quickly. On the other hand, when the engine is in a region with a higher intake air amount than the line Q6-R6, both the primary turbo supercharger 204 and the secondary turbo supercharger am 206 operate to ensure the intake flow rate and obtain appropriate supercharging pressure. It will be done.

Figure 4 shows the relationship between the solenoid operating state of each valve and the transition of the operating state (the left side of the horizontal axis is the low intake air amount region, and the right side is the high intake air amount region) based on the characteristic diagram in Figure 3 above. This is what I saw. As can be seen from this figure, the hysteresis of the opening/closing operation of the exhaust cut valve 223 is completely included in the hysteresis of the opening/closing operation of the intake cut valve 232. Note that even if the intake cut valve 232 control solenoid 238 is turned on at Q6 and R6, the actual opening operation of the intake cut valve 232 is delayed due to the action of the differential pressure detection valve 250, as shown by the broken line in the figure. Therefore, Q6 and R6 are set close to or on the same line as Q4 and R4 of the exhaust cut valve 223 opening control as described above. On the other hand, the intake cut valve 23
The closing operation of No. 2 does not involve the above-mentioned delay with respect to the operation of the solenoid 238, so the setting line Q
5, R5 must satisfy Q5<Q3, R5<R3.

Next, fuel injection valves 219, 22 based on position sensors 255, 256 and pressure sensors 257, 258
0 control will be explained based on the flow shown in FIG. After starting, first read the engine speed, boost pressure, intake air amount, etc. in step S1, then step S! determines the current engine operating range. Next, in step S3, the operating region of the engine is changed to a low intake air amount region (a quiet region where only the briny turbo supercharger 204 operates) or a high intake air amount region (
(area in which both the primary and secondary exhaust turbo superchargers 204, 206 operate). If the answer is No, which is in the low intake air amount range, the process returns, while if it is YES, which is in the high intake air amount area, the process proceeds to step S4, and it is determined whether the intake relief valve 235 is left open. That is, two pressure sensors 257
, 258 is less than a predetermined value, it is determined that the intake relief valve 235 is open.

If it is determined that the intake relief valve 235 is left open, the fuel cut line is changed in step S7 and the process returns. Here, this fuel cut line is normally set as shown by the solid line in Figure 6, and fuel injection is not performed on the higher rotation side or higher boost side (area shown with diagonal lines in Figure 6) than the fuel cut line. This controls the fuel supply from the valves 219 and 220 to be stopped. Note that the broken lines shown in the figure indicate a low intake air amount region (“P region” where only the primary turbo supercharger 204 operates) and a high intake air amount region (both the primary and secondary exhaust turbo superchargers 204, 206 is a switching line that separates the "P+S area" in which it operates.

In step S7, as shown in FIG. 7, the fuel cut line is changed to match this switching line to expand the area where fuel supply is stopped. Through this process, the engine 201 is operated only in a low intake air amount region, and the secondary turbo supercharger 206 is deactivated. This can prevent the secondary turbo supercharger 206 from operating while the intake relief valve 235 is left open, and can prevent problems due to insufficient supercharging of the secondary blower 213.

On the other hand, when it is determined in step S4 that the intake relief valve 235 is closed, the process proceeds to step S5, and the position sensor 255 determines whether the exhaust cut valve 223 is fully closed.
Determine by. If it is determined that it is left closed, the process proceeds to step S7, where the fuel cut line is changed in the same manner as described above, the secondary turbo supercharger 206 is made inactive, and the process returns. This makes it possible to avoid increasing the amount of fuel in a state of insufficient supercharging, thereby preventing poor combustion.

Furthermore, when it is determined in step S5 that the exhaust cut valve 223 is open, the process advances to step S6, and the position sensor 256 determines whether the intake cut valve 232 is fully closed.
Determine by. If it is determined that it is left closed, the process proceeds to step S7, where the fuel cut line is changed in the same manner as described above, the secondary turbo supercharger 206 is made inactive, and the process returns. As a result, the intake cut valve 23
Even if blower 2 fails and remains closed, the secondary blower 2
13 does not cause surging, and the reliability of the secondary turbocharger 206 is improved.

On the other hand, if it is determined in step S6 that the intake cut valve 232 is open, it is determined that there is no abnormality in each valve 223, 232, 235, and the process returns directly.

In the above flow, in step S6, the operating state detection means 30 detects the operating state of the intake cut valve 232.
1 is in charge. In addition, another step constitutes a supercharger control means 302 that receives the output of the operating state detection means 301 and prohibits the operation of the secondary turbo supercharger 206 when the intake cut valve 232 is closed in a specific operating region. are doing.

In this embodiment, the operating state of the intake cut valve 232 is detected based on the position◆ sensor 256, but the operating state of the intake cut valve 232 is detected based on the detected pressures of the two pressure sensors 257 and 258. It is also possible. That is, if the intake cut valve 232 is left closed while the exhaust cut valve 223 and the exhaust leak valve 230 are open and the intake relief valve 235 is closed, the pressure on the upstream side of the intake relief valve 235 and the pressure on the downstream side The pressure difference between the pressure and the pressure increases. Therefore, by detecting this increase in differential pressure, it can be determined that the intake cut valve 232 is left closed.

Another method for determining whether the intake relief valve 235 is left open is to
There is a method of detecting the rotation speed of the turbine and determining that the turbine is left open when this rotation speed exceeds the allowable rotation speed. This method can also be used to determine whether the exhaust cut valve 223 is left closed. Furthermore, another method for determining whether the exhaust cut valve 223 is left closed is to detect the rotation speed of the secondary turbine 207,
There is also a method of determining that the turbine is open when the turbine rotation speed is below the surging limit rotation.

Next, control of each valve based on the characteristics shown in FIG. 3 will be explained using a control circuit shown in FIG. 8. The intake relief valve operating solenoid 243 is connected to the first comparison circuit 11 shown at the top of the figure.
It is controlled by the output of the first OR circuit 121 which receives as input the output of 1 and the output of the second comparison circuit 112 shown below. Here, the first comparison circuit 111 compares the intake air amount Q, which is the detection signal of the air flow meter 221, and the output value of the first addition circuit 131, which is a reference value. The first adder circuit 131 is manually inputted with a setting value Q1 corresponding to the Q1 line in FIG.
Q'+-Q2) is input through the first gate 141, and when the first gate 141 is opened, the first comparison circuit uses Q++Q'1-Q2 as a reference value. 111, and when the first gate 141 is closed, the first comparison circuit 1
Output to 11. The first gate 141 is opened and closed by the output of the first OR circuit 121.

The second comparison circuit 112 compares the engine rotation speed R detected by the engine rotation speed sensor with the output value of the second addition circuit 132, which is a reference value. The second adder circuit 132 receives the setting value R, which corresponds to the R1 line in FIG. When the second gate 142 is opened, R, +R', -R2 are output as reference values to the second comparator circuit 112, and When the second gate 142 is closed, it outputs R1 as a reference value to the second comparison circuit 112. second gate 1
42 is also opened and closed by the output of the first OR circuit 121.

The first and second comparison circuits 111 and 112 convert the detected intake air filQ and engine rotation speed R into a first
and the respective reference values, which are the outputs of the second adder circuit, and turn ON when Q or R exceeds the reference value.
A signal is output to the intake relief valve operating solenoid 243 (when turned ON, the intake relief valve 235 is closed). The first and second gates 141 and 142 are connected to the first OR circuit 12.
It is closed when the output signal of No. 1 is ON, and is opened when the OR circuit signal is OFF. Therefore, at the time of transition from the low intake air amount area to the high intake air amount area, the output signal of the first OR circuit 121 is OFF, so each gate 141
．． 142 is opened and the first and second comparison circuits 111,1
12 as a standard value. , R2 is manually operated. Therefore, when it reaches the 0 2r R2 line in Figure 3, it turns ON.
A signal is issued and the intake relief valve 235 is opened. Also,
This ON signal causes the first and second gates 141,
142 is closed, so that the reference values of Q and R become Ql and Rl, respectively. In other words, Q /1, R'l
The line is set in preparation for a transition in the opposite direction with a hysteresis corresponding to .

The exhaust cut valve actuation solenoid 240 is also controlled by a similar control circuit. That is, a third comparison circuit 113 is provided for the intake air 1aQ, and a fourth comparison circuit 114 is provided for the engine speed R, and the outputs of these comparison circuits 113 and 114 are sent to the second OR circuit. 122
is sent to the solenoid 240 via. A third adder circuit 133 is connected to the third comparison circuit 113;
A fourth addition circuit 134 is similarly provided for the comparison circuit 114 of FIG. Then, in the third addition circuit 133,
The set value Q3 is input manually, and Q'3 (however, Q3 +Q'3 =Q4) is inputted manually via the third gate 143. Similarly, the fourth addition circuit 134 has a set value R
3 and R′3 (where R
3 +R' 3-R4) is manually performed. Similarly, the fourth addition circuit 134 has a set value R3 and a fourth gate 14.
R'3 via 4 (however, R3 + R' 3-R4
) is input. This circuit operates in the same manner as the first and second comparison circuits described above, so that when transitioning to the high intake air amount region, Q4. The exhaust cut valve 223 is opened based on the R4 line, and when transitioning to the low intake air amount region, the Q3. Valve 223 by R3 line
is activated to close. Furthermore, the wastegate valve operating solenoid 245 is also simultaneously controlled by the control signal output to the exhaust cut valve operating solenoid 240.

For the intake cut valve operating solenoid 238, the fifth
and the outputs of the sixth comparator circuits 115 and 116 are connected to the third O
A similar IQ control circuit is provided which feeds through R circuit 123. This control circuit includes each comparison circuit 11
5,116, the fifth and sixth adder circuits 135,1
36, and also includes fifth and sixth gates 145, 146 for each adder circuit 135, 136.

The basic operation is the same as the circuit for each valve described above. In other words, when transitioning to the high intake air amount area, the Q61R
Intake cut valve opening control is performed using line 6, and when transitioning to a low intake air amount region, intake cut valve closing control is performed using lines Qs and Rs. Here, Q6 and R6 are similarly Qs +Q' s =Q6, R5 +R' s
=R6.

However, in the case of this intake cut valve control circuit, a seventh gate 147 is connected to the output side of the third OR circuit 123, and a control signal is sent to the solenoid 238 via this gate 147.

and the second OR circuit 12 for operating the exhaust cut valve.
A timer 150 is provided that starts counting up from when the output of 2 changes from ON to OFF.
A seventh comparison circuit 117 is provided that issues an ON signal when the count value of this timer 150 exceeds a set value (for example, a value corresponding to 2 seconds), and the ON signal is output from this seventh comparison circuit 117. At this time, the seventh gate 147 is closed to forcibly close the intake cut valve 232, and at the same time, the reference values of Q and H are changed to Q6 and R6, and the timer 150 is reset. . once the 7th
When the gate 147 of the seventh comparison circuit 117 closes, the seventh comparison circuit 117
The output of is turned OFF, but since the reference value which is the switching line has been changed to Q61R6 as described above, the intake cut valve operating solenoid 238 is maintained in the closed operating state. This prevents surging from occurring due to the intake cut valve solenoid 240 remaining in the ON state for a long time while the exhaust cut valve solenoid 238 is in the OFF state during the transition to the low intake air amount region.

In the above embodiment, the two superchargers 204 and 206 are both exhaust turbo superchargers, but the present invention can be applied as long as the secondary supercharger is an exhaust turbo supercharger. , other types of superchargers may be used, such as mechanical superchargers.

Furthermore, although the above embodiment describes a rotary piston engine, the present invention is not limited to this, and the present invention can also be applied to control devices for other types of supercharged engines, such as reciprocating engines. .

(Effect of Q light) As explained above, according to the control device for a supercharged engine of the present invention, a plurality of superchargers including an exhaust turbo supercharger are arranged in parallel in the intake passage. At least one of the exhaust turbo superchargers is designated as a secondary turbo supercharger, and the secondary turbo supercharger is operated only in a specific operating range, and an intake passage dedicated to the secondary turbo supercharger is provided with an intake cut that closes outside of the above specific operating range. By installing a valve, the operation of the secondary turbo supercharger is prohibited when the intake cut valve is closed in a specific operating range.This prevents surging of the secondary side blower in the event of a failure of the intake cut valve, and prevents the operation of the secondary turbo supercharger. reliability can be improved.

[Brief explanation of drawings]

The drawings illustrate embodiments of the present invention; FIG. 1 is a general schematic diagram, FIG. 2 is a sectional view of the differential pressure detection valve, FIG. 3 is a control characteristic diagram, and FIG. 4 is an explanation of the operating state of the device. 5 is a flowchart explaining the control of the control unit, FIGS. 6 and 7 are characteristic diagrams showing the fuel cut line, and FIG. 8 is a diagram showing the control circuit. 302...supercharger control means

Claims (1)

[Claims] (1) Multiple superchargers including an exhaust turbo supercharger are arranged in parallel in the intake passage, and at least one of the exhaust turbo superchargers is designated as a secondary turbo supercharger, and the secondary turbo supercharger is used only in a specific operating range. In a supercharged engine that operates a turbo supercharger, an intake cut valve that closes outside of the above specified operating range is provided in the intake passage dedicated to the secondary turbo supercharger, and the operating state of the intake cut valve is controlled. and a supercharger control means for receiving the output of the operating state detecting means and prohibiting the operation of the secondary turbo supercharger when the intake cut valve is closed in a specific operating range. A control device for a supercharged engine featuring: