JPH0392539A - Control device for turbosupercharged engine - Google Patents

Abstract

PURPOSE:To improve the responsiveness of an exhaust cut valve by providing an exhaust relief passage connected to turbine upstream side portions of exhaust turbosuperchargers of exhaust passages, and temporarily increasing the opening of an exhaust relief valve provided in the middle of it during the transition to a high-intake air quantity range. CONSTITUTION:Two exhaust passages 202 and 203 arranged with turbines 205 and 207 of the primary and secondary turbosuperchargers 204 and 206 connected to cylinders are communicated to each other by a communicating path 222 at the upstream of superchargers 204 and 206, and an exhaust cut valve 223 is provided at the immediate downstream of the opening position of the communicating path 222 on the secondary exhaust passage 203. The middle of the communicating path 222 and a merge exhaust passage 224 are communicated by a waste gate passage 225. An exhaust relief passage 228 communicating passages 225 and 203 is provided, and the opening of an exhaust relief valve 230 provided in the middle of it is temporarily increased during the transition from a low-intake air quantity range to a high-intake air quantity range.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention includes a plurality of exhaust turbo superchargers, and enables or disables some of the exhaust turbo superchargers depending on the intake air amount of the engine. The present invention relates to a control device for a turbocharged engine.

(Prior Art) Conventionally, as this type of turbocharged engine, for example, as disclosed in Japanese Utility Model Application Publication No. 178329/1983,
The turbines of the primary and seventh exhaust turbo superchargers are installed in parallel in the exhaust passage, and the blowers of these two exhaust turbo superchargers are connected to the intake passage of the engine, and the turbine of the secondary turbo supercharger is connected to the upstream side of the turbine of the secondary turbo supercharger. An exhaust cut valve is installed in the exhaust passage of the engine, and if the intake air amount is less than the set value, the exhaust cut valve is closed in the low intake air amount range, the secondary turbo supercharger is inactivated, and the exhaust gas from the exhaust passage is blocked. High boost pressure is ensured by intensively supplying air to the turbine of the secondary turbo supercharger, while the exhaust cut valve is opened in the high intake air volume range where the intake air volume is higher than the set value. There is a known system in which the exhaust gas from the exhaust passage is supplied to the turbines of two exhaust turbo superchargers to obtain an appropriate supercharging pressure while ensuring the amount of intake air. In such a turbocharged engine, when an exhaust cut valve is provided in the exhaust passage, the exhaust cut valve is installed in the exhaust passageway to prevent the exhaust cut valve from opening inadvertently due to exhaust pulsation. The structure is such that the exhaust cut valve is closed by pressure, and in a high intake air amount region, the exhaust cut valve is opened by the actuator against the force received from the exhaust pressure.

(Problem to be Solved by the Invention) In such a turbocharged engine, when the exhaust cut valve opens when transitioning from a low intake air amount region to a high intake air amount region, such as during acceleration, the exhaust cut valve must be opened. The exhaust cut valve is difficult to open because it opens against the force exerted by the exhaust pressure.
Its responsiveness is poor.

As a result, the start-up of rotation of the secondary turbocharger is delayed, causing torque shock.

Furthermore, since the exhaust cut valve is opened against the force received from the exhaust pressure, a large driving force is required from the actuator.

Incidentally, in such a turbocharged engine, an exhaust leak passage is provided in the exhaust passage that bypasses the exhaust cut valve, and an exhaust leak valve is provided in the exhaust leak passage to change the intake air amount from a low intake air amount range to a high intake air amount range. When the transition to In addition to adjusting the supercharging pressure characteristics, exhaust gas is used to run up the secondary turbocharger to give it a pre-rotation, thereby improving the start-up of the secondary turbocharger in a high intake air amount region.

The present invention has been made with attention to these points,
The purpose of this is to: When transitioning from a low intake air amount area to a high intake air amount area, before opening the exhaust cut valve,
To reduce the difference in exhaust pressure before and after an exhaust gas cut valve by using an exhaust leakage passage, to make the exhaust gas cut valve easier to open, to improve responsiveness of the exhaust gas cut valve, and to reduce its driving force.

(Means for Solving the Problem) In order to achieve the above object, in the present invention, the exhaust gas is cut from the exhaust leakage passage prior to the opening operation of the exhaust cut valve at the time of transition from the low intake air amount region to the high intake air amount region. Exhaust gas is supplied to the exhaust passage downstream of the valve.

Specifically, the solution taken by the present invention is that a plurality of exhaust turbo superchargers are arranged in parallel in the intake passage, and at least one of the exhaust turbo superchargers is used as a secondary turbo supercharger. An exhaust cut valve is installed in the exhaust passage dedicated to the turbo supercharger so that it receives exhaust pressure in the closing direction, and the exhaust cut valve is opened only in the high intake air volume region of the engine to operate the secondary turbo supercharger. This assumes an engine with a turbocharger. In contrast, an exhaust leakage passage is connected at one end to an exhaust passage upstream of the exhaust cut valve and at the other end to an exhaust passage between the exhaust cut valve and the exhaust turbo supercharger. , an exhaust leak valve that is provided in the exhaust leak passage and opens in a low intake air amount region;
A leakage valve control means is provided for temporarily increasing the opening degree of the exhaust leakage valve prior to the opening operation of the exhaust cut valve at the time of transition from the low intake air amount region to the high intake air amount region 1\. It is something.

(Function) According to the above structure, in the present invention, the exhaust cut valve is provided in the exhaust passage so as to receive exhaust pressure in the closing direction.
The exhaust cut valve is prevented from opening inadvertently due to exhaust pulsation in a low intake air amount region, and the exhaust passage dedicated to the secondary turbocharger is stably closed.

Also, when transitioning from a low intake air amount area to a high intake air amount area,
Under the control of the leakage valve control means, the opening degree of the exhaust leakage valve is temporarily increased prior to the opening operation of the exhaust cut valve, and the exhaust gas upstream of the exhaust cut valve is supplied to the downstream of the exhaust cut valve, and the exhaust gas is supplied before and after the exhaust cut valve. The differential pressure of the exhaust pressure decreases. This makes it easier to open the exhaust cut valve, improves the responsiveness of the exhaust cut valve, speeds up the startup of rotation of the secondary turbocharger, and reduces torque shock.

Furthermore, since the force that the exhaust gas cut valve receives from the exhaust pressure is small, the driving force for the exhaust gas cut valve can be small.

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

FIG. 1 shows a two-row rotary piston engine with a turbo supercharger 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 turbocharger 204 is placed on one side, and the secondary turbocharger 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 primary turbo supercharger 204 is in the middle of the first branch passage 210, and the blower 211 of the primary turbo supercharger 204 is in the middle of the second branch passage 212. The blower 213 of the secondary turbo supercharger 206 is installed. These branch passages 210 and 212 are formed 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 section of the engine 201, and is connected to each intake boat (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, 212 to detect the amount of intake air.

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

The exhaust cut valve 223 is rotatably supported by the exhaust passage wall at a portion of its peripheral edge.

On the other hand, a stepped portion is provided on the exhaust passage wall so that the diameter becomes smaller toward the exhaust downstream side. And exhaust cut valve 2
23 is provided so that, in its closed position, the entire peripheral edge abuts the stepped portion from the exhaust upstream side and receives exhaust pressure in the closing direction.

Moreover, when opening, it rotates from the closed position so as to oppose the exhaust flow and is positioned at the open position along the exhaust passage wall.

In addition, an evening bottle 20 extending from the middle of the communication path 222 is provided.
A waste gate passage 225 is formed which communicates with the combined exhaust passage 224 downstream of 5,207, and a diaphragm type actuator 226 is provided in the waste gate passage 225.
A waste gate valve 227 is provided which is linked to the waste gate valve 227.

Then, the waste gate passage 225 and the exhaust passage 20
3 through an exhaust leak passage 228. The exhaust leak passage 228 has one end connected to the waste gate passage 2.
The waste gate valve 25 is connected to the upstream side of the waste gate valve, that is, the exhaust passage upstream of the exhaust cut valve 223, and the other end is connected to the exhaust passage 203 between the exhaust cut valve 223 and the secondary turbine 207. There is. The exhaust leak passage 228 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. On the other hand, the branch passage 2 in which the blower 213 of the secondary turbocharger 206 is disposed
12, an intake cut valve 232 is disposed downstream of the blower 213. This intake cut valve 232 is composed of a butterfly valve, and is also driven by a diaphragm type actuator 2.
33. Further, a relief passage 234 is formed in the branch passage 212 on the secondary side so as to bypass the blower 213.
4 is provided with a diaphragm type intake relief valve 235.

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. Further, a conduit 257 is connected to the conduit 236, and the conduit 257 is
It is connected upstream of the blower 211 of the branch passage 210 in which the blower 211 of the primary turbocharger 204 is disposed. A duty solenoid valve 255 is provided in the conduit 257, and by adjusting its duty ratio, the pressure introduced from downstream of the blower 7211 is adjusted as appropriate. Through this adjustment, the pressure in the pressure chamber of the actuator 229 is adjusted, and the opening degree of the exhaust leak valve 230 is changed. This exhaust leak valve 23
0 opens, a small amount of exhaust gas flows through the exhaust leakage passage 228 and is supplied 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 port of the 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 for operating 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, 2
43,245, duty solenoid valve 255
The two fuel injection valves 219 and 220 are controlled by a control unit 246 configured using a microcomputer. control unit 24
In addition to the output signal of the engine rotation speed sensor and the output signal of the air flow meter 221, the throttle opening, the supercharging pressure P1 downstream of the blower 211 on the hybrid side, etc. are input manually to 6.

One manual boat 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 input boat 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 . Furthermore, one input port of the three-way valve 240 for controlling the exhaust gas cut valve is open to the atmosphere, and the other human-powered boat is
It is connected via a conduit 252 to the conduit 247 which is connected to the negative pressure tank 248 . On the other hand, one input boat 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 boat is open to the atmosphere. In addition, the waste gate valve 227
One input boat of the three-way control valve 245 is open to the atmosphere, and the other manual boat is connected by a conduit 254 to the conduit 236 communicating with the downstream side of the floor 211 on the primary side. A constricted portion 256 is provided between the connection portion of the conduit 236 with the conduit 254 and the connection portion with the conduit 257.

As shown in FIG. 2, the differential pressure detection valve 250 has three chambers 264, 265.
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 boat 270 is opened at the center of the end wall of the casing 261, and an atmosphere release boat 271 is opened at the side wall. The first diaphragm 262 includes a second diaphragm 26.
A valve body 272 is fixedly installed, passing through the third chamber 266 and extending toward the output boat 270 of the third chamber 266.

The first human-powered boat 267 is connected to the second human-powered boat by a conduit 273.
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 primary floor 211 into the first chamber 264.

The second input boat 269 is also connected upstream of the intake cut valve 232 by a conduit 274, so that the second input boat 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 boats 267 and 269
2 (P2 - Pi) exceeds a predetermined value, the valve body 27
2 opens output port 270. This output port 270 is connected via conduit 249 to one of the three-way valves 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 secondary side supercharging pressure P2 approaches the primary side supercharging pressure P1, the differential pressure PL-P2 disappears, and 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 the three-way valve 245 is on, it communicates with the downstream side of the primary side blower 211 via the conduits 254 and 236, and when the 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. In addition, in order to prevent intake air from flowing backward into the secondary side proa when the exhaust cut valve 223 closes and the intake cut valve 232 remains open during the transition from the high intake air amount area to the low intake air amount area, this area is The intake cut valve 232 is forcibly closed after a predetermined time (for example, 2 seconds) has elapsed starting from the time when the exhaust cut valve 223 is closed.

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, the engine speed R is low, or the intake air mQ is small, the intake relief valve 235 is opened.
Pre-rotation of the secondary turbocharger 206 is performed by opening the exhaust leakage valve 230. 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.

Then, at the time of transition from the low intake air amount region to the high intake air amount region, the opening degree of the exhaust leak valve 230 is specifically increased prior to the opening operation of the exhaust cut valve 223.

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, the lines Q6 and R6 of Joki, which turn on the solenoid 238 for controlling the intake force 1 sotovalve 232 from OFF to ON, are set ε taking into account the delay caused by the differential pressure detection valve 250, and as a result, the lines Q6 and R6 are set to Cut valve 223 control solenoid 240 is O
It is assumed that the line is close to the line of Q4 and R4 that turn on from FF. Also, these Q6. R6 can also be made to match Q4 and R4.

Conversely, when transitioning from a high intake air amount region to a low intake air amount region, the solenoid type three-way valves 238, 240, and 243 that control the intake cut valve 232, the exhaust cut valve 223, and the intake relief valve 235 have hysteresis. With the third
As shown by broken lines in the figure, Q5-R5. Q3-R3
, Ql-Rl. 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 located on the binaural no-load line or the no-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 turbocharger 206 is stopped, so only the primary turbocharger 204 is activated. As a result, high boost pressure can be obtained quickly. On the other hand, when the engine is in a higher intake air amount region than the above line Q6-R6, both the primary turbo supercharger 204 and the secondary turbo supercharger 206 operate to maintain the appropriate supercharging pressure while ensuring the intake flow rate. will be obtained.

Further, since the exhaust cut valve 223 is provided in the exhaust passage 203 so as to receive exhaust pressure in the closing direction, the exhaust cut valve 223 is prevented from opening inadvertently due to exhaust pulsation in a low intake air amount region. The exhaust passage 203 dedicated to the secondary turbocharger is stably closed.

Furthermore, when transitioning from the low intake air amount region to the high intake air Ω region, the opening degree of the exhaust leak valve 230 was temporarily increased prior to the opening operation of the exhaust cut valve 223, so that the exhaust gas upstream of the exhaust cut is supplied downstream of the exhaust cut valve 223, and the differential pressure between the exhaust pressures before and after the exhaust cut valve 223 is reduced. As a result, the exhaust cut valve 223 becomes easier to open, the responsiveness of the exhaust cut valve 223 improves, and the secondary turbo supercharger 20
6's rotation start-up becomes faster and torque shock is reduced.

This will be explained with reference to FIG. In the figure, the solid line indicates the conventional example, and the broken line indicates the example of the present invention. In other words, when transitioning from a low intake air amount area to a high intake air amount area,
The opening degree of the exhaust leak valve 230 temporarily increases and then closes. Therefore, the differential pressure between the exhaust pressure PU on the exhaust upstream side of the exhaust cut valve 223 and the exhaust pressure pD on the exhaust downstream side, (Pu
-Po) immediately decreases, and the exhaust cut valve 223 opens with good response. Therefore, secondary turbo supercharger 2
The start-up of the 06 rotation is improved, which eliminates the drop in supercharging pressure.

In addition, the force that the exhaust cut valve 223 receives from the exhaust pressure becomes smaller due to the reduction in the differential pressure of the exhaust pressure before and after the exhaust cut valve, so the driving force of the exhaust cut valve 223 is small, and the actuator 231 can be made compact. .

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, control of each valve based on the characteristics shown in FIG. 3 will be explained using control circuits shown in FIGS. 6 and 7.

The intake relief valve operating solenoid 243 is connected to the output of the first comparison circuit 111 shown at the top of the figure and the second comparison circuit shown below.
The output of the comparison circuit 112 is controlled by the output of the first OR circuit 121 which is operated manually. Here, the first comparison circuit 111 uses the intake air ffiQ, which is the detection signal of the air flow meter 221, and the first addition circuit 13, which is the reference value.
This is to compare the output value of 1. And the above first
The adder circuit 131 receives the set value Q1 to be applied to the Q1 line in FIG. is configured to be input, and the first
When the gate 141 of is opened, Q+ +Q' l-Q
! is output to the first comparison circuit 111 as a reference value, and when the first gate 141 is closed, Q1 is output to the first comparison circuit 111 as a reference value. 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 has a set value R1 corresponding to the Rl line in FIG. is configured to be input via the second
When the gate 142 is opened, Rl + R' I is outputted to the second comparison circuit 112 using R2 as the reference value, and when the second gate 142 is closed, the second comparison is performed using R1 as the reference value. Output to circuit 112. The second gate 142 is also opened and closed by the output of the first OR circuit 121.

The first and second comparison circuits 111 and 112 compare the detected intake air IAQ and the engine rotation speed R with the respective base values that are the outputs of the first and second addition circuits, and compare Q or R. When the value exceeds a reference value, an ON signal is output to the intake relief valve operating solenoid 243 (when ON, the intake relief valve 235 closes). The first and second gates 141 and 142 are connected to the first OR circuit 121
It is closed when the output signal of is ON, and is opened when the OR circuit signal is OFF. Therefore, when transitioning from the low intake air amount area to the high intake air amount area, the first OR circuit 1
21 output signal is OFF, and each gate 141,
142 is opened and the first and second comparison circuits 111.11
Q.2 as a reference value. , R2 are input. Therefore, when the lines Q2 and R2 are reached in FIG. 3, an ON signal is issued and the intake relief valve 235 is opened. Also, this O
The first and second gates 141, 142 are activated by the N signal.
is closed, so that the reference values of Q and R become Ql and Rl, respectively. In other words, the line is set with hysteresis corresponding to Q'1 and R'l in preparation for a shift in the opposite direction.

The exhaust cut valve actuation solenoid 240 is also controlled by a similar control circuit. In other words, the third comparison circuit 113 also detects the engine rotation speed R with respect to the intake air mQ.
A fourth comparison circuit 114 is provided for this, and the outputs of these comparison circuits 113 and 114 are sent to the solenoid 240 via the second OR circuit 122. Third comparison circuit 1
Similarly, a third addition circuit 133 is provided for 13, and a fourth addition circuit 134 is provided for fourth comparison circuit 114. The set value Q3 is input manually to the third adder circuit 13, and Q'3 (Q3 +Q'3-Q4) is inputted via the third gate 143. Similarly, the fourth addition circuit 134 has a set value R3,
R′3 (where R3 +
R'3-R4) is manually generated. Similarly, the fourth addition circuit 134 has a set value R3 and a fourth gate 144.
R′3 (where R ] + R′3 −
R4) is done manually. This circuit operates in the same manner as the first and second comparison circuits described above, whereby the exhaust cut valve 223 is opened based on the QJ and RJ lines in FIG. 3 when transitioning to the high intake air amount region. Furthermore, when shifting to the low intake air amount region, the valve 223 is closed by the Q3 and R3 lines. Furthermore, the wastegate valve actuation solenoid 245 is also simultaneously controlled by the control signal output to the exhaust cut valve actuation 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 control circuit is provided which feeds through R circuit 123. This control circuit includes each comparison circuit 115
, 116, the fifth and sixth adder circuits 135, 13
6, 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 region, Q6. R6
The intake cut valve opening control is performed by the lines Qs and Rs, and the intake cut valve closing control is performed by the lines Qs and Rs when transitioning to the low intake air amount region. Here, Q6 and R6 are similarly Qs +Q' s-Q6, R5 +R' 5-R6
It is set in the form of

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. When the seventh gate 147 is closed and the intake cut valve 232 is forcibly closed, the reference values of Q and H are set to Q6. R6 and also resets the timer 150. 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 Qs and Rs 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.

Next, a control circuit for controlling the duty solenoid valve 255 will be explained with reference to FIG. Reference numeral 181 denotes a duty ratio selection circuit, which calculates a pace duty ratio D, which is a basic duty ratio according to the driving condition, based on the throttle opening degree and engine speed, and manually inputs this pace duty ratio D to the addition circuit 137. I try to let them do it. Further, 182 is a target boost pressure selection circuit, which determines a target boost pressure according to the operating condition based on the throttle opening degree and the engine speed, and the correction amount setting circuit 182
I am trying to have it input to 3. This correction amount setting circuit 1
The actual boost pressure is also input to 83, and the duty ratio is corrected ffi according to the difference between the target boost pressure and the actual boost pressure.
D+ is set.

This correction ffi D + is manually input to the addition circuit 137. Then, in this adder circuit 137, the pace duty ratio D and the correction ffiD+ are added, and the duty solenoid
Valve 255 is controlled.

On the other hand, 151 is a timer that starts counting upon receiving an exhaust cut valve opening signal for opening the exhaust cut valve 223, and outputs an ON signal when the time is up, and
8 is opened, and the setting value D2 is input manually to the addition circuit 137.

The timer 151 is reset upon receiving an exhaust cut valve close signal for closing the exhaust cut valve 223. Therefore, when the exhaust cut valve opening signal is received during transition from the low intake air amount area to the high intake air amount area, the timer 151 starts counting, and until the timer 151 times out, the addition circuit 137 The output duty ratio is (D
+D1) to (D+DI +D2). As a result, the opening degree of the exhaust leak valve 230 is temporarily increased prior to the opening operation of the exhaust cut valve 223.

The circuit shown in FIG. 7 provides leakage valve control that specifically increases the opening degree of the exhaust leakage valve 230 prior to the opening operation of the exhaust cut valve 223 when transitioning from the low intake air amount area to the high intake air amount area. It constitutes means 301.

Further, although the above embodiment describes a low-reciprocal piston engine, the present invention is not limited to this, and the present invention is also applicable to control devices for other types of turbocharged engines, such as reciprocating engines. be able to.

(Effects of the Invention) As explained above, according to the control device for a turbocharged engine of the present invention, a plurality of exhaust turbochargers are arranged in parallel in the intake passage, and at least one of them is arranged in parallel. The exhaust turbo supercharger is used as a secondary turbo supercharger. An exhaust cut valve is installed in the exhaust passage dedicated to the secondary turbo supercharger so as to receive exhaust pressure in the closing direction, and the exhaust is cut only in the high intake air amount region of the engine. The valve is opened to operate the secondary turbo supercharger, and one end is connected to the exhaust passage upstream of the exhaust cut valve, and the other end is connected to the exhaust passage between the exhaust cut valve and the exhaust turbo supercharger. an exhaust leakage passage connected to the exhaust leakage passage, and an exhaust leakage valve that is provided in the exhaust leakage passage and opens in a low intake air amount area, and the exhaust cut valve Since the opening degree of the exhaust leak valve is temporarily increased prior to the opening operation of the When transitioning from the intake air amount range to the high intake air amount range, the differential pressure between the exhaust pressures before and after the exhaust cut valve decreases, making it easier to open the exhaust cut valve, improving the responsiveness of the exhaust cut valve, and reducing torque shock. In addition, the driving force of the exhaust cut valve can be reduced.

[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. FIG. 5 is an explanatory diagram showing temporal fluctuations in supercharging pressure, etc., and FIGS. 6 and 7 are diagrams showing control circuits. 203... Exhaust passage 204... Primary turbo supercharger 206... Secondary turbo supercharger 223... Exhaust cut valve 228... Exhaust leak passage 230... Exhaust leak valve 301... Leakage valve control means 2 Fig. 4 Fig. 5 Fig. 6

Claims (1)

[Claims] (1) A plurality of exhaust turbo superchargers are arranged in parallel in the intake passage, and at least one of the exhaust turbo superchargers is set as a secondary turbo supercharger in an exhaust passage dedicated to the secondary turbo supercharger, In an engine with a turbo supercharger, an exhaust cut valve is provided to receive exhaust pressure in the closing direction, and the exhaust cut valve is opened only in a high intake air amount region of the engine to operate a secondary turbo supercharger. is connected to the exhaust passage upstream of the exhaust cut valve, and the other end is connected to the exhaust passage between the exhaust cut valve and the exhaust turbo supercharger; and an exhaust leak passage provided in the exhaust leak passage. and an exhaust leakage valve that opens in a low intake air volume range, and a temporary control of the opening of the exhaust leakage valve before opening the exhaust cut valve when transitioning from a low intake air volume range to a high intake air volume range. 1. A control device for an engine equipped with a turbo supercharger, characterized in that a control device for an engine with a turbo supercharger is provided.