JPH0396620A - Control device for engine with turbo-charger - Google Patents

Abstract

PURPOSE:To damp shock due to torque at the transition time of operating conditions by controlling supercharging pressure to be increased for the specified period of time from the time before an exhaust cut valve is so actuated as to be opened to the time until supercharging pressure is built up to a specified one with said valve actuated to be opened when transition is required from a low air intake range to a high air intake range. CONSTITUTION:Exhaust passages 202 and 203 to which the turbines 203 and 207 of a primary and a secondary turbo-supercharger 204 and 206 are interposed respectively, are communicated with each other by a communicating passage 222 at the upstream sides of the respective superchargers 204 and 206 and an exhaust cut valve 223 is provided for the exhaust passage 203 at a position adjacent to the downstream of the open position of the communicating passage 222. In addition, a waste gate valve 227 acting as a supercharging pressure regulating means is provided for a waste gate passage 225 which communicates the middle of the communicating passage 222 with a joint exhaust passage 224. When the transition of operating conditions is required from a low air intake range to a high air intake range, the opening of the waste gate valve 227 is controlled in order to increase supercharging pressure for a specified period of time from the time before the exhaust cut valve 223 is so actuated as to be opened to the time until supercharging pressure is built up to a specified one with the aforesaid valve actuated to be opened.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention includes a plurality of exhaust turbo superchargers, and operates some of the exhaust turbo superchargers only in a high intake air amount region of the engine. The present invention relates to a control device for a turbocharged engine.

(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 intake 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.
A known system is 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 ensuring the amount of intake air.

(Problem to be solved by the invention) In such a turbocharged engine, when a transition from a low intake air amount region to a high intake air amount region is requested, such as during acceleration, ■ When the exhaust cut valve opens, the primary turbo overflow occurs. A sudden decrease in the flow rate of exhaust gas supplied to the feeder.

■On the other hand, in the low intake air amount range, the secondary turbo supercharger is either stopped or at most is running at extremely low speeds, so the secondary turbo supercharger reaches the speed at which supercharging is possible. It takes time.

For these reasons, the boost pressure temporarily drops and torque shock occurs.

By the way, in such an engine with a turbo supercharger, a waste gate passage that bypasses the turbine of the primary turbo supercharger is provided in the exhaust passage, and a waste gate valve is provided in the waste gate passage, so that the exhaust gas of the exhaust turbo supercharger is When the intake pressure downstream of the blower exceeds a predetermined value, the waste gate valve is opened to relieve a portion of the exhaust gas supplied to the turbine of the primary turbocharger into the exhaust passage downstream of the turbine, thereby improving the boost pressure characteristics. It will be done to optimize the

If this wastegate valve is opened and closed without being limited to the purpose of optimizing the boost pressure characteristics, it functions as a boost pressure adjusting means for adjusting the boost pressure. For example, a device that adjusts the fuel injection amount or a device that adjusts the ignition timing can also function as the supercharging pressure adjusting means in the same manner as described above.

The present invention has been made with attention to these points,
The purpose of this is to increase the pressure of the exhaust gas supplied to the secondary turbo supercharger using this supercharging pressure adjustment means when a transition from a low intake air amount region to a high intake air amount region is required, such as during acceleration. The purpose is to alleviate the drop in supply pressure.

In that case, for example, if the exhaust pressure is increased too much, the supercharging pressure becomes excessive (over-supercharging), and problems such as knocking occur. Therefore, in the present invention, this exhaust pressure is appropriately increased.

(Means for Solving the Problems) In order to achieve the above object, in the present invention, when a transition from a low intake air amount region to a high intake air amount region is requested, such as during acceleration, a boost pressure adjustment means is used to respond to the operating state. to increase boost pressure.

Specifically, the solution taken by the present invention is to arrange a plurality of exhaust turbo superchargers in parallel in the intake passage, as shown in FIG. As a secondary turbo supercharger, an exhaust cut valve is provided in the exhaust passage dedicated to the secondary turbo supercharger, and the exhaust cut valve is opened only in the high intake air amount region of the engine to operate the secondary turbo supercharger. Assumes a supercharged engine. In response to this, an operating state detecting means 301 that detects the operating state of the engine, a supercharging pressure adjusting means 227 that adjusts the supercharging pressure, a supercharging pressure detecting means 257 that detects the supercharging pressure, and a supercharging pressure detecting means 257 that detects the supercharging pressure. In response to the outputs of the state detection means 301 and the boost pressure detection means 257, when a transition from the low intake air amount region to the high intake air amount region is requested, the supercharging pressure changes from before the opening operation of the exhaust cut valve to after the opening operation. A supercharging pressure control means 3 that controls the supercharging pressure adjusting means 227 to increase the supercharging pressure for a predetermined period of time until the pressure reaches a set pressure according to the operating state.
02 is provided.

(Function) With the above configuration, in the present invention, the secondary turbo supercharger is inactive in the low intake air amount region, and exhaust gas is intensively supplied to the superchargers other than the secondary turbo supercharger. While boost pressure is secured, the secondary turbocharger operates in the high intake air flow range and exhaust gas is supplied to both exhaust turbochargers, ensuring appropriate boost pressure while ensuring intake flow rate. can get.

Then, based on the detection by the boost pressure detection means 257, the boost pressure adjustment means 227 is controlled by the boost pressure control means 302, and when a transition from the low intake air amount region to the high intake air amount region is requested, the above-mentioned Since the supercharging pressure is increased for a predetermined period from before the exhaust cut valve opens until the supercharging pressure reaches the set pressure after the opening operation, the pressure of the exhaust gas supplied to the secondary turbo supercharger increases, and the secondary turbo The rotational speed of the supercharger increases quickly with good responsiveness, the drop in supercharging pressure is alleviated, and torque shock is prevented from occurring.

In that case, based on the detection by the driving state detection means 301,
Since the set pressure is changed according to the operating condition, the exhaust pressure can be appropriately increased, and problems such as knocking due to overcharging can be avoided.

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

FIG. 2 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. The two exhaust passages 202 and 203 merge into one exhaust passage 224 downstream of both turbines 205 and 207.

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 proar 213 of the secondary turbo supercharger 206 is disposed. 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. A throttle sensor 258 is connected to the throttle valve 216, and the opening degree of the throttle valve 216 is detected by the throttle sensor 258. The downstream end of the intake passage 209 is branched into two independent intake passages 217 corresponding to each cylinder of the engine 201.
218, and is connected to each intake port (not shown). Fuel injection valves 219 and 220 are provided in each of these independent intake passages 217 and 218, respectively.

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. Further, the surge tank 215 is provided with a supercharging pressure sensor 257 as supercharging pressure detection means for detecting supercharging pressure. Further, 259 is a water temperature sensor that detects the engine cooling water temperature, 260 is a fuel sensor that detects the type of fuel supplied to the engine (regular gasoline, high-octane gasoline, etc.), and 281 is a rotational speed sensor that detects the engine speed. The number sensor 282 is a shift sensor that detects the shift position of a transmission connected to the engine.

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, 205. 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, a turbine 205, which extends from the middle of the communication path 222,
A waste gate passage 225 is formed which communicates with the combined exhaust passage 224 downstream of 207, and the waste gate passage 22
5 is provided with a waste gate valve 227 to which a diaphragm type actuator 226 is linked. A leak passage 228 is formed that communicates the upstream part of the waste gate valve 227 in the waste gate passage 225 with the downstream part of the exhaust cut valve 223 in the exhaust passage 203 connected to the secondary turbine 207. An exhaust leak valve 230 is provided which is linked to the actuator 229 of the exhaust gas leak valve 230 .

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 operated 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 proa 213.
4 is provided with a diaphragm type intake relief valve 235.

The actuator 22 that operates the exhaust leak valve 230
9 connects the brimary turbo supercharger 204 via the conduit 236.
Blower 2 of branch passage 210 in which blower 211 of
11 downstream.

When the pressure acting on the conduit 236 exceeds a predetermined value, the actuator 229 is actuated to open the exhaust leak valve 230, thereby opening the exhaust cut valve 223.
When the passage 228 is closed, a small amount of exhaust gas leaks through the passage 228.
and is supplied to the secondary turbine 207.

Therefore, the secondary turbo supercharger 206 starts rotating in advance before the exhaust cut valve 223 opens.

The conduit 236 includes a duty solenoid valve 2.
55 are provided. The duty solenoid valve 255 is connected to the intake passage 210 upstream of the primary blower via a conduit 256. Therefore, by adjusting the duty ratio of the duty◆ solenoid valve 255, the exhaust leak valve 230 is opened and closed.

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
As will be described later, the relief passage 23 is closed until a predetermined time before the exhaust cut valve 223 and the intake cut valve 232 open.
Leave 4 open. As a result, the leak passage 22
Secondary turbo supercharger 2 by exhaust gas flowing through 8
06 pre-rotates, the pressure upstream of the intake cut valve 232 rises and enters the surging region, and the rotation of the blower 213 is increased.

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

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
6 includes an output signal of the air flow meter 221, an output signal of the boost pressure sensor 257, an output signal of the throttle sensor 258, an output signal of the water temperature sensor 259, and a fuel sensor 260.
, the output signal of the rotation speed sensor 281, the output signal of the shift sensor 282, etc., are input manually, and the control described below is performed based on them.

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 of the three-way valves 240 for controlling the exhaust gas cut valve is open to the atmosphere, and the other one is open to the atmosphere.
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 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 input port is open to the atmosphere. In addition, the waste gate valve 227
One input port of control three-way valve 245 is open to the atmosphere, and the other manual port is connected to conduit 236 by conduit 254 . Therefore, when the three-way valve 245 is opened, the duty solenoid valve 255
By adjusting the duty ratio of the waste gate valve 227
I'm trying to open and close it. That is, the waste gate valve 227 functions as a supercharging pressure adjusting means for regulating supercharging pressure.

As shown in FIG. 3, 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, 26 second input boats are opened in the second chamber 265 in the middle, and in the third chamber 266 on the other end side, an output boat 270 is opened in the center of the end wall of the casing 261, and an output boat 270 is opened in the side wall of the casing 261. The atmosphere release boat 271 is opened. 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 manpower port 267 is connected by a conduit 273 to a third
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 7211 into the first chamber 264.

The second human-powered boat 269 is also connected upstream of the intake cut valve 232 by a conduit 274, and thus is connected to 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 - PL) exceeds a predetermined value, the valve body 27
2 opens the output boat 270. This output port 270 is connected via a conduit 249 to one of the input ports of a 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 in communication with 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 Pi-P2 disappears, and the differential pressure P2-PL 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
is OFF, it communicates with a conduit 236 via a conduit 254, and when the pressure in this conduit 236 exceeds a predetermined value, the actuator 226 operates to close the wastegate valve 227.
is opened to relieve exhaust gas and optimize boost pressure characteristics. Further, when the three-way valve 245 is ON, the air is released to the atmosphere and the waste gate valve 227 is closed.

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 blower when the exhaust cut valve 223 closes and the intake cut valve 232 remains open during the transition from the high intake air amount region to the low intake air amount region, 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. 4 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 the electromagnetic solenoid three-way valves 238, 240, 243, 245 and the duty solenoid valve 255 are controlled based on this map.

When transitioning from a low intake air amount region to a high intake air amount region, the intake relief valve 235 is open in a region where the engine speed R is low or the intake air mQ is small.
The opening of the exhaust leak valve 230 causes the secondary turbocharger 206 to rotate 1,000 revolutions. Then, when the engine speed reaches R2 or the intake air amount reaches the 02-R2 line, the solenoid type three-way valve 243 for controlling the intake relief valve 235 is turned ON, the intake relief valve 235 is closed, and then the exhaust gas is cut off. Until the valve 223 opens, the pressure downstream of the secondary pro 7213 increases. When the line Q4-R4 is reached, the exhaust cut valve 2
The solenoid type three-way valve 240 for controlling the intake cut valve 232 is turned ON and the exhaust cut valve 223 opens, and then the Q6-R6 line is reached, the solenoid type three-way valve 238 for controlling the intake cut valve 232 is turned ON, and the intake cut valve 223 is opened. 232 opens, supercharging by the secondary turbo supercharger 206 begins. 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 233 that drives the intake cut valve 232 is not controlled only by the operation of the solenoid 238, but is supplied with atmospheric pressure, which is the pressure source that opens the intake cut valve 232, via the differential pressure detection valve 250. Therefore, the actual opening operation of the intake cut valve 232 is delayed with respect to the operation of the solenoid 238. Therefore, the intake cut valve 232
Q above to turn the control solenoid 238 from OFF to ON
The line Q6, R6 is set in consideration of the delay caused by the differential pressure detection valve 250, and as a result, the line Q6, R6 changes from the OFF to the OFF state of the exhaust cut valve 223 control solenoid 240.
It is assumed that the line is close to the line of Q4 and R4 which becomes N.

Also, these Q6, R6 and 04. R4 can also be matched.

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. Fourth
As shown by broken lines in the figure, Q5-R5. Q3-R3
, Ql-Rl. That is, when transitioning from a high intake air amount area to a low intake air amount area, Q3. When the R3 line 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 normally connected to the solenoid 245 for controlling the exhaust cut valve 223.
0 ON, OFF line Q4-R4, Q3-R3
are matched with each line. That is, when transitioning from a low intake air amount region to a high intake air amount region, the solenoid 245 is turned from ON to OFF on the line Q4-R4. Also,
Q3 when transitioning from high intake air amount area to low intake air amount area
- Turn the solenoid 245 from OFF to ON on the R3 line.

When it is determined that there is a request to shift from the low intake air amount area to the high intake air amount area, for example when the throttle valve opening increases by more than a predetermined amount, the After the opening operation, the waste gate valve 227 is forcibly closed for a predetermined period until the boost pressure reaches a set pressure depending on the operating state. That is, when it is determined that there is a transition request, the three-way valve 245 is turned OFF and the waste gate valve 227 is immediately closed. Then, the exhaust cut valve 223 is opened, and then the supercharging pressure sensor 2
When the supercharging pressure detected by 57 reaches the set pressure, the three-way valve 245 is turned on to enable the waste gate valve 227.

In that case, the set pressure is changed depending on the operating state. That is, (1) the lower the shift position of the transmission, the lower the set pressure is set. This is because the lower the speed gear, the faster the engine speed rises and the faster the boost pressure rises, so taking into consideration the responsiveness of the wastegate valve 227, the wastegate valve 227 should be opened a little before the target boost pressure is reached. This is to prevent overcharging by outputting a command to open 227.

■The higher the engine acceleration, the lower the set pressure is set. This is intended to prevent over-supercharging for the same reason as in case (2) above.

■The set pressure when regular gasoline is supplied is lower than the set pressure when high-octane gasoline is supplied. Since knocking is likely to occur when regular gasoline is supplied, the boost pressure is kept low to prevent knocking.

■If the engine cooling water temperature is outside the appropriate temperature range, the set pressure is set low. That is, since knocking is likely to occur when the engine is cold or hot, the boost pressure is kept low to prevent knocking.

■The set pressure is set low until the vehicle travels a predetermined distance. This is to keep the supercharging pressure low at the beginning of use, taking into account that the supercharging pressure decreases over time.

Incidentally, 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 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.

Furthermore, when a transition from the intake air amount region to the high intake air amount region is requested, the waste gate valve 227 is closed for a predetermined period from before the exhaust cut valve 223 is opened until the boost pressure reaches the set pressure after the opening operation. Therefore, this waste gate valve 22
7 is prohibited, and the pressure of the exhaust gas supplied to the secondary turbo supercharger 206 increases. Therefore, the rotational speed of the secondary turbocharger 206 increases quickly with good responsiveness, the drop in supercharging pressure is alleviated, and torque shock is prevented from occurring.

In that case, change the above set pressure to . Changes are made according to the transmission shift position, engine acceleration, fuel type, engine coolant temperature, and vehicle mileage, so exhaust pressure is appropriately increased to prevent overcharging and knocking. Problems such as prevention and prevention of supercharging pressure drop due to aging can be avoided.

Figure 5 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 4 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 solenoid 238 for controlling the intake cut valve 232 is turned on at 06 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 04 and R4 of the exhaust cut valve 223 opening control as described above.

On the other hand, the closing operation of the intake cut valve 232 does not involve the above-mentioned delay with respect to the operation of the solenoid 238.
The setting line Q5, R5 is Q5<Q3, R5<
It is necessary to set it to R3.

Next, control of each valve based on the characteristics shown in FIG. 4 will be explained using a control circuit shown in FIG. 6. The intake relief valve operating solenoid 243 is connected to the first comparison circuit 11 shown at the top of the figure.
1 and the output of the second comparison circuit 112 shown below it are controlled by the output of the first OR circuit 121 which is manually operated. 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') is manually 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 11 uses Q1 as a reference value.
Output to 1. 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 R1 line in FIG. 1
42, and when the second gate 142 is opened, the R. 10R'l-R2 is output as a reference value to the second comparison circuit 112, and when the second gate 142 is closed, R1 is output 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 compare the detected intake air amount Q and engine rotation speed R with respective reference values that are outputs of the first and second addition circuits, and compare Q or R. outputs an ON signal to the intake relief valve operating solenoid 243 when the
When turned on, the intake relief valve 235 closes). The first and second gates 141 and 142 are closed when the output signal of the first OR circuit 121 is ON, and are 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 12
Since the output signal of gate 1 is OFF, each gate 141, 1
42 is opened and the first and second comparison circuits 111.112
Q2. R2 is input. therefore,
When the lines Q2 and R2 are reached in FIG. 4, an ON signal is issued and the intake relief valve 235 is opened. Also, this ON
The signal closes the first and second gates 141 and 142, so that the reference values of Q and R become Ql and Rl, respectively. In other words, the line is set with a hysteresis corresponding to Q'1+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, for the intake air amount Q, the third comparison circuit 113 also calculates the engine speed R.
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 to the third adder circuit 133, and Q'3 (Q3 +Q'3-Q4) is input 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 input. Similarly, the fourth
The adder circuit 134 contains the set value R3 and the fourth gate 1.
R'3 via 44 (where R3 +R' 3 =
Ra) is manually operated. This circuit is connected to the first and second circuits described above.
It operates in the same way as the comparison circuit, so that when transitioning to the high intake air amount region, Q4 in FIG. 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 2 by R3 line
23 is operated to close.

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, Qs, R6
The intake cut valve opening control is performed using the Qs. Intake cut valve closing control is performed using the Rs line. Here, Q6 and R6 are similarly Qs 1Q' s =Q6, R5 +R' 5-
It is set in the form of 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*R6, and the timer 150 is reset. . Once the seventh gate 147 is closed, the seventh comparison circuit 11
7 becomes OFF, but the reference value, which is the switching line, is set to Qs. Since the intake cut valve operating solenoid 238 is changed to Rs, 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 circuit for controlling the waste gate valve 227 will be explained. 120 is a tenth comparison circuit,
The output signal of the throttle sensor 258 is input to the comparison circuit 120. This comparison circuit 120 determines whether the output signal of the throttle sensor 258 exceeds a set value. When it is determined that the set value has been exceeded,
It is determined that there is a request for transition from the low intake air amount area to the high intake air amount area, and an ON signal is continuously output to the wastegate valve solenoid 245 until the exhaust cut valve 223 opens. Close.

Further, 118 is an eighth comparison circuit, and the comparison circuit 1
18, the output signal of the OR circuit 122 is input manually. This comparison circuit 118 determines whether the output signal of the OR circuit 122 "changed from ON to OFF" or "changed from OFF to ON." When the output signal of the OR circuit 122 changes from OFF to ON, that is, when the exhaust cut valve 223 switches from closing operation to opening operation, the supercharging pressure changes depending on the operating state after the exhaust cut valve 223 opens. wastegate valve solenoid 2 until the set pressure is reached.
45 continues to output an ON signal to close it, and the waste gate valve 227 is closed. On the other hand, when the output signal of the OR circuit 122 changes from ON to OFF, that is, when the exhaust cut valve 223 switches from open operation to close operation, the waste gate valve solenoid 245 is opened without outputting an ON signal to it. Then, the waste gate valve 227 is allowed to operate. Specifically, a normally open eighth gate 148 is connected to the comparison circuit 118, and the output signal of the gate 148 is manually inputted to the wastegate valve solenoid 245. On the other hand, numeral 11 is a ninth comparison circuit which receives the output of the boost pressure sensor 257 and outputs a signal to the gate 148 to close the gate 148 when the boost pressure exceeds the set pressure. That's what I do. Here, the set pressure is changed by the outputs of various sensors 259, 260, 281, and 282. Therefore, when the output signal of the OR circuit 122 changes from OFF to ON, the comparison circuit 118 outputs an ON signal and the waste gate valve 227 closes, and then, when the boost pressure exceeds the set pressure and the gate 148 closes,
The input of the ON signal to the wastegate valve solenoid 245 is cut off, and the operation of the wastegate valve 227 is permitted.

In the above configuration, each sensor 259, 260, 28
1,282 constitutes an operating state detection means 301 that detects the operating state of the engine. Also, comparison circuit 1
The operating state detection means 301 is detected by the circuit downstream from 18.
In response to the output of the boost pressure sensor (boost pressure detection means) 257, when a transition from the low intake air amount area to the high intake air amount area is requested, the A supercharging pressure control means 3 that controls the waste gate valve (supercharging pressure adjusting means) 227 to increase the supercharging pressure for a predetermined period until the supply pressure reaches a set pressure according to the operating state.
02.

In the above embodiment, the waste gate valve 227 is used as a supercharging pressure adjusting means, and the supercharging pressure is increased by closing the waste gate valve 227 for a predetermined period of time. It is possible to increase For example, in the case of a fuel injection type engine, the fuel injection amount adjusting device may be used as a supercharging pressure adjusting means, and the fuel injection amount may be increased for a predetermined period to increase the supercharging pressure. Further, the ignition timing adjusting device may be used as a supercharging pressure adjusting means, and the ignition timing may be advanced by a predetermined period to increase the supercharging pressure.

Further, although the above embodiments have been described with respect to a rotary piston engine, the invention is not limited to this, and the present invention can also be applied to control devices for other types of turbocharged engines, such as reciprocating engines. I can do it.

(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, and an exhaust cut valve is provided in the exhaust passage dedicated to the secondary turbo supercharger, and the exhaust cut valve is opened only in a high intake air amount region of the engine to operate the secondary turbo supercharger. When the exhaust cut valve is activated and a transition from the low intake air amount region to the high intake air amount region is requested, the boost pressure is set at a predetermined level from before the exhaust cut valve is opened until the boost pressure reaches the set pressure according to the operating condition after the exhaust cut valve is opened. By increasing the boost pressure during this period, we achieved the basic effect of securing high boost pressure in the low intake air volume range and obtaining appropriate boost pressure while securing the intake flow rate in the high intake air volume range. At the same time, when a transition from a low intake air amount region to a high intake air amount region is requested, the pressure of the exhaust gas supplied to the secondary turbo supercharger can be increased while avoiding problems such as knocking due to overcharging. It is possible to increase the rotation speed of the secondary turbocharger with good response and to quickly increase the rotation speed of the secondary turbo supercharger, thereby alleviating the drop in supercharging pressure and preventing the occurrence of torque shock.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of the present invention. 2 to 6 illustrate examples of the present invention, and FIG. 2 is an overall schematic configuration diagram,
FIG. 3 is a sectional view of the differential pressure detection valve, FIG. 4 is a map showing the operating area of each valve, FIG. 5 is an explanatory diagram explaining the operation of each valve, and FIG. 6 is a control circuit diagram. 206...Secondary turbo supercharger 223...Exhaust cut valve 227...Waste gate valve (supercharging pressure adjustment means) 25
7... Boost pressure sensor (boost pressure detection means) 301...
Operating state detection means 302...Supercharging pressure control means 204...Brimary turbo supercharger 204...Brimary turbo supercharger 206...Secondary turbo supercharger 223...Exhaust cut valve 227 ...waste gate valve (supercharging pressure adjustment means) 25
7...Supercharging pressure sensor (supercharging pressure detection means) 301...Operating state detection means 302...Supercharging pressure control means 1 Company Coff "i-1" Figure 1

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 used as a secondary turbo supercharger to exhaust air into an exhaust passage dedicated to the secondary turbo supercharger. Operating state detection means for detecting the operating state of the engine in a turbocharged engine that is provided with a cut valve and opens the exhaust cut valve only in a high intake air amount region of the engine to operate a secondary turbo supercharger. a boost pressure adjusting means for adjusting the boost pressure; a boost pressure detecting means for detecting the boost pressure; When a transition to the high intake air amount region is requested, the above-mentioned boost pressure is increased for a predetermined period from before the exhaust cut valve opens until the boost pressure reaches the set pressure according to the operating condition after the opening operation. 1. A control device for a turbocharged engine, comprising a boost pressure control means for controlling a boost pressure adjustment means.