JP2770861B2 - Control device for engine with turbocharger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention is provided with a plurality of exhaust turbochargers so that some of the exhaust turbochargers are operated only in a high intake air amount range of an engine. The present invention relates to a control device for a turbocharged engine.

2. Description of the Related Art Conventionally, as a turbocharged engine having two exhaust turbochargers, for example, as disclosed in Japanese Utility Model Laid-Open Publication No. 60-178329, a primary and secondary exhaust turbocharger is provided in an exhaust passage. Turbocharger turbines are provided in parallel, the blowers of the two exhaust turbochargers are connected to the intake passage of the engine, and an exhaust cut valve is provided 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 smaller than the set value, the exhaust cut valve is closed to disable the secondary turbocharger, and the exhaust gas from the exhaust passage is intensively supplied to the turbine of the primary turbocharger In the high intake air amount range where the intake air amount is larger than the set value, the exhaust cut valve is opened to operate the secondary turbocharger, and That the exhaust gas is supplied to the turbine of the two exhaust turbochargers and to obtain a proper boost pressure while ensuring the intake air amount it is known.

(Problems to be Solved by the Invention) In such an engine with a turbocharger, when a request for transition from a low intake air amount region to a high intake air amount region such as during acceleration is made, when the exhaust cut valve is opened, the primary turbocharger is provided. A sudden decrease in the flow rate of exhaust gas supplied to the machine.

On the other hand, in the low intake air amount range, the secondary turbocharger was stopped or was running at very low speed at best, so until the secondary turbocharger reached a superchargeable speed. It takes time.

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

By the way, in such an engine with a turbocharger,
A wastegate passage that bypasses the turbine of the primary turbocharger is provided in the exhaust passage, a wastegate valve is provided in the wastegate passage, and when the intake pressure downstream of the blower of the exhaust turbocharger becomes equal to or higher than a predetermined value. Then, the wastegate valve is opened to relieve a part of the exhaust gas supplied to the turbine of the primary turbocharger to an exhaust passage downstream of the turbine, thereby optimizing the supercharging pressure characteristic. If this wastegate valve is opened and closed without being bound by the purpose of optimizing the boost pressure characteristics, it functions as a boost pressure adjusting means for adjusting the boost pressure. Then, for example, a device for adjusting the fuel injection amount or a device for adjusting the ignition timing can also function as the boost pressure adjusting means as in the above.

The present invention has been made in view of such a point. The purpose of the present invention is to provide a boost pressure adjusting means when a transition from a low intake air amount range to a high intake air amount region is required, such as during acceleration. Therefore, the pressure of the exhaust gas supplied to the secondary turbocharger is increased to mitigate the drop in the supercharging pressure.

In this case, for example, if the exhaust pressure is excessively increased, the supercharging pressure becomes excessively large (oversupercharging), and problems such as knocking occur. Therefore, in the present invention, the exhaust pressure is appropriately increased.

(Means for Solving the Problems) In order to achieve the above object, according to the present invention, at the time of a shift request from a low intake air amount range to a high intake air amount region such as during acceleration,
The supercharging pressure adjusting means increases the supercharging pressure according to the operation state.

Specifically, the solution taken by the invention of claim 1 is the first solution.
As shown in the drawing, a plurality of exhaust turbochargers are arranged in parallel in an intake passage, and at least one of the exhaust turbochargers is used as a secondary turbocharger as an exhaust passage dedicated to the secondary turbocharger. It is assumed that an engine with a turbocharger is provided with an exhaust cutoff valve, and the exhaust cutoff valve is opened only in a high intake air amount range of the engine to operate a secondary turbocharger. On the other hand, the operating state detecting means 301 for detecting the operating state of the engine, the supercharging pressure adjusting means 227 for adjusting the supercharging pressure, the supercharging pressure detecting means 257 for detecting the supercharging pressure, Upon receiving the outputs of the state detecting means 301 and the supercharging pressure detecting means 257, when the shift request from the low intake air amount range to the high intake air amount region is requested, the supercharging pressure is increased before the opening operation of the exhaust cut valve and after the opening operation. A supercharging pressure control means 302 for controlling the supercharging pressure adjusting means 227 so as to increase the supercharging pressure for a predetermined time until reaching a set pressure according to the operating state is provided.

Here, in the invention of claim 2, it is assumed that the set pressure in claim 1 is changed according to the operating state. According to a third aspect of the present invention, the set pressure in the second aspect is set to be lower as the shift position of the transmission is at a lower speed. In the invention of claim 4, the set pressure in claim 2 is set to be lower as the acceleration of the engine is higher. Further, claim 5
In the present invention, the set pressure in claim 2 is set lower when regular gasoline is supplied than when high-octane gasoline is supplied.

According to a sixth aspect of the present invention, there is provided an exhaust turbo-type first supercharger that operates at least in a low flow rate region of an intake air amount and an exhaust turbo-type second supercharger that operates in a high flow rate range. And an engine with a turbocharger arranged in parallel. Then, the first exhaust passage in which the turbine of the first supercharger is provided, the second exhaust passage in which the turbine of the second supercharger is provided, and the second exhaust passage are opened and closed. An exhaust cut valve, a first intake passage in which a blower of the first supercharger is interposed, a second intake passage in which a blower of the second supercharger is interposed, and the second supercharger. An intake cutoff valve that opens and closes a second intake passage downstream of the blower of the feeder, operating state detecting means that detects an operating state of the engine, and an output of the operating state detecting means that receives the output of the operating state detecting means and operates in the high flow rate region of the intake air amount. Switching control means for opening the exhaust cut valve and the intake cut valve to switch the second supercharger from a non-operation state to an operation state. Further, a wastegate valve for adjusting the supercharging pressure to a predetermined pressure, a supercharging pressure detecting means for detecting the supercharging pressure, and receiving the output of the operating state detecting means and the supercharging pressure detecting means to reduce the intake air amount. A supercharging pressure control means for controlling the waste gate valve so as to increase the supercharging pressure at the time of a shift request from the flow rate region to the high flow rate region is provided.

(Operation) With the above configuration, in the inventions of claims 1 to 6, in the low intake air amount range, the secondary turbocharger is inoperative and exhaust gas is concentrated on the turbocharger other than the secondary turbocharger. In the high intake air amount range, the secondary turbocharger operates and exhaust gas is supplied to both exhaust turbochargers, ensuring high intake pressure. High boost pressure is obtained.

Then, based on the detection of the supercharging pressure detecting unit 257, the supercharging pressure adjusting unit 227 is controlled by the supercharging pressure control unit 302,
When requesting a transition from a low intake air amount range to a high intake air amount region,
For example, from before the opening operation of the exhaust cut valve, for a predetermined period until the supercharging pressure reaches the set pressure after the opening operation, the supercharging pressure is increased, so the pressure of the exhaust gas supplied to the secondary turbocharger increases, The rotation speed of the secondary turbocharger quickly rises with good responsiveness, so that the drop in the supercharging pressure is reduced, and the occurrence of torque shock is prevented.

Further, in this case, since the set pressure is changed according to the operation state based on the detection of the operation state detection means 301, the exhaust pressure is appropriately increased, and, for example, the occurrence of knocking due to over-supercharging, etc. Bugs are avoided.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 2 shows a two-rotor type rotary piston engine with a turbocharger provided with a control device according to an embodiment of the present invention. In FIG. 1, reference numeral 201 denotes an engine, and exhaust passages 202 and 203 of each cylinder are provided independently of each other. The turbine 205 of the primary turbocharger 204 is disposed in one of the two exhaust passages 202 and 203, and the turbine 207 of the secondary turbocharger 206 is disposed in the other. That is, in the engine 201, the exhaust passages 202, 203 of each cylinder are independently guided to the turbines 205, 207 of the primary and secondary exhaust turbochargers 204, 206, so that the two exhaust turbochargers 204, 2
In the region where supercharging is carried out by 06, the exhaust dynamic pressure is
The supercharging efficiency is improved by effectively acting on 207.
The two exhaust passages 202 and 203 merge into a single exhaust passage 224 downstream of the turbines 205 and 207.

In addition, the intake passage 209 is divided into two downstream of an air cleaner (not shown), a blower 211 of the primary turbocharger 204 is provided in the middle of the first branch passage 210, and is provided in the middle of the second branch passage 212. Is provided with a blower 213 of a secondary turbocharger 206. These branch passages 210, 212
They are formed so as to face each other at the branching portion and extend substantially straight on both sides. Further, the two branch passages 210 and 212 merge again downstream of the respective blowers 211 and 213. An intercooler 214 is disposed in the single intake passage 209 again, and a surge tank 215 is disposed downstream of the intercooler 214. A throttle valve 216 is disposed between the intercooler 214 and the surge tank 215. Has been established. A throttle sensor 258 is connected to the throttle valve 216, and the opening of the throttle valve 216 is detected by the throttle sensor 258. 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). Fuel injection valves 219 and 220 are provided in the independent intake passages 217 and 218, respectively.

An air flow meter 221 for detecting the amount of intake air is provided upstream of the intake passage 209 at an upstream of a branch portion of the first and second branch passages 210 and 212. Further, the surge tank 215 is provided with a supercharging pressure sensor 257 as a supercharging pressure detecting means for detecting a supercharging pressure.
Furthermore, 259 is a water temperature sensor that detects the temperature of the engine cooling water, 260 is a fuel sensor that detects the type of fuel supplied to the engine (regular gasoline or high-octane gasoline, etc.), and 281 is a rotation that detects the number of revolutions of the engine. A number sensor 282 is a shift sensor that detects a shift position of a transmission connected to the engine.

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 205. The exhaust passage 2 in which the secondary turbine 207 is disposed
In 03, an exhaust cut valve 223 is provided immediately downstream of the opening position of the communication passage 222. A wastegate passage 225 extending from the middle of the communication passage 222 and communicating with a combined exhaust passage 224 downstream of the turbines 205 and 207 is provided. The wastegate passage 225 has a diaphragm-type actuator 226.
The wastegate valve 227 is provided with a link. A leakage passage 228 is provided for communicating the upstream portion of the waste gate valve 227 of the waste gate passage 225 with the exhaust cut valve 223 downstream of the exhaust passage 203 connected to the secondary turbine 207, and the leakage passage 228 has a diaphragm type. An exhaust leak valve 230 linked to the actuator 229 is provided.

The exhaust cut valve 223 is a diaphragm type actuator 2
It is linked to 31. On the other hand, in the branch passage 212 where the blower 213 of the secondary turbocharger 206 is provided, an intake cut valve 232 is provided downstream of the blower 213. The intake cut valve 232 is formed of a butterfly valve, and is similarly linked to a diaphragm type actuator 233. A relief passage 234 is formed in the branch passage 212 on the secondary side so as to bypass the blower 213, and a diaphragm-type intake relief valve 235 is provided in the relief passage 234.

The above actuator 229 for operating the exhaust leak valve 230
Is blower of primary turbocharger 204 by conduit 236
211 is connected to the downstream of the blower 211 of the branch passage 210 provided. Then, when the pressure acting on the conduit 236 becomes equal to or higher than a predetermined value, the actuator 229 operates to open the exhaust leak valve 230, whereby the exhaust cut valve 223
When is closed, a small amount of exhaust gas flows through the leakage passage 228 and is supplied to the turbine 207 on the secondary side. Therefore, the secondary turbocharger 206 has the exhaust cut valve 2
Rotation starts before 23 opens.

The conduit 236 has a duty solenoid valve 255
Is provided. The duty solenoid valve
255 is connected via a conduit 256 to the intake passage 210 upstream of the primary side blower. Therefore, the exhaust leakage valve 230 is opened and closed by adjusting the duty ratio of the duty solenoid valve 255.

The pressure chamber of the actuator 233 that operates the intake cut valve 232 is connected by a conduit 237 to the output port of an electromagnetic solenoid type three-way valve 238. Also, the exhaust cut valve 223
Is connected to the output port of another three-way valve 240 of the electromagnetic solenoid type via a conduit 239. Further, the pressure chamber of the actuator 241 that operates the intake relief valve 235 is connected by a conduit 242 to the output port of another three-way valve 243 of an electromagnetic solenoid type.
The intake relief valve 235 is connected to the exhaust cut valve 223 as described later.
The relief passage 234 is kept open until a predetermined time before the intake cut valve 232 is opened. Thus, when the secondary turbocharger 206 is pre-rotated by the exhaust gas flowing through the leakage passage 228, the pressure upstream of the intake cut valve 232 is suppressed from rising and entering the surging region. Increase rotation.

The actuator 226 for operating the wastegate valve 227 is connected to the electromagnetic solenoid type three-way valve 24 by a conduit 244.
Connected to 5 output ports.

Above four solenoid three-way solenoid valves 238,240,243,24
5. The duty solenoid valve 255 and the two fuel injection valves 219 and 220 are controlled by a control unit 246 configured using a microcomputer. The control unit 246 includes the air flow meter 2
21, an output signal of the supercharging pressure sensor 257, an output signal of the throttle sensor 258, an output signal of the water temperature sensor 259, an output signal of the fuel sensor 260, an output signal of the rotation speed sensor 281,
An output signal of the shift sensor 282 and the like are input, and control described later is performed based on the input signal.

One input 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 input port is connected to a differential pressure detection valve described later via a conduit 249. Connected to 250 output ports 270. The intake negative pressure downstream of the throttle valve 216 is introduced into the negative pressure tank 248 via a check valve 251. One input port of the three-way valve 240 for controlling the exhaust cut valve is open to the atmosphere, and the other input port is connected to the conduit 25.
2, the conduit 24 connected to the negative pressure tank 248.
Connected to 7. 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. One input port of the three-way valve 245 for controlling the wastegate valve 227 is open to the atmosphere, and the other input port is connected to the conduit 236 by the conduit 254. Therefore,
When the three-way valve 245 is opened, the waste gate valve 227 is opened and closed by adjusting the duty ratio of the duty solenoid valve 255. That is, the wastegate valve 227 functions as a boost pressure adjusting unit that adjusts the boost pressure.

As shown in FIG. 3, the differential pressure detecting valve 250 has a casing 261 in which two first and second diaphragms 2 are provided.
It is divided into three rooms 264,265,266 by 62,263. In the first chamber 264 at one end thereof, a first input port 267 is opened, and a compression spring 268 is disposed between the inner surface of the end of the casing 261 and the first diaphragm 262. . Further, a second input port 269 is opened in the middle second chamber 265, and a third chamber 266 on the other end side is provided with a second input port 269.
An output port 270 is opened at the center of the end wall of the casing 261 and an atmosphere opening port 271 is opened at the side wall. And
The first diaphragm 262 is fixedly provided with a valve body 272 which extends through the second diaphragm 263 and extends toward the output port 270 of the third chamber 266.

As shown in FIG. 3, the first input port 267 is connected to the downstream side of the intake cut valve 232 by a conduit 273, and the supercharging pressure P1 downstream of the primary side blower 211 is supplied to the first chamber 264.
To be introduced. Also, the second input port 269 is connected by a conduit 274 upstream of the intake cut valve 232,
The pressure P2 on the upstream side of the intake cut valve 232 when the intake cut valve 232 is closed is introduced. Difference between pressures P1 and P2 introduced from both input ports 267 and 269 (P2-P1)
Is greater than or equal to a predetermined value, the valve element 272 opens the output port 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 ON, the conduit 237 connected to the pressure chamber of the actuator 233 for operating the intake cut valve 232 is connected to the output port of the differential pressure detection valve 250.
In the state of being connected to 249, the pressure upstream of the intake cut valve 232, that is, the supercharging pressure P2 on the secondary side approaches the supercharging pressure P1 on the primary side, the differential pressure P1−P2 disappears, and further, the differential pressure P2 When −P1 becomes larger than a predetermined value, the atmosphere is introduced into the actuator 233, and the intake cut valve 232 is opened.
When the three-way valve 238 is turned off and the conduit 237 on the actuator 233 side communicates with the conduit 247 connected to the negative pressure tank 248, a negative pressure is supplied to the actuator 233, and the intake cut valve 232 is closed. .

On the other hand, 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 leading to the pressure chamber to the conduit 252 on the negative pressure tank 248 side, The actuator 231 is closed by being supplied with a negative pressure. When the three-way valve 240 is turned on to open the output-side conduit 239 to the atmosphere, the exhaust cut valve 223 is opened, and supercharging is performed by the secondary turbocharger 206.

When the three-way valve 243 for controlling the intake relief valve 235 is OFF and the conduit 242 leading to the pressure chamber of the actuator 241 for operating the intake relief valve 235 is connected to the negative pressure tank 248 side, the intake relief valve 235 When the three-way valve 243 is turned ON and the conduit 242 connected to the pressure chamber of the actuator 241 is opened to the atmosphere, the valve 243 is closed.

Also, an actuator 226 for operating the waste gate valve 227
When the three-way valve 245 for control of the wastegate valve 227 is OFF, the wastegate valve 245 communicates with the conduit 236 via the conduit 254, and when the pressure of the conduit 236 exceeds a predetermined value, the actuator 226 operates to activate the wastegate valve. By opening 227, the exhaust gas is relieved to optimize the supercharging pressure characteristics. When the three-way valve 245 is ON, it is opened to the atmosphere and the wastegate valve 227 closes.

In this embodiment, hysteresis is provided for the opening and closing operations of the exhaust cut valve 223, the intake cut valve 232, and the intake relief valve 235, as described later. Also, when shifting from the high intake air amount region to the low intake air amount region, the exhaust cut valve 22
In order to prevent the backflow of intake air to the secondary-side blower when 3 is closed and the intake cut valve 232 remains open, a predetermined time (for example, 2 seconds) elapses in this region starting from when the exhaust cut valve 223 is closed. Later, the intake cut valve 232 is forcibly closed.

FIG. 4 is a control map showing the open / close control of the intake cut valve 232, the exhaust cut valve 223, the intake relief valve 235, and the wastegate valve 227, together with the open / close control of the exhaust leak valve 230. The map is stored in the control unit 246, and the electromagnetic solenoid type three-way valves 238, 240, 243, 245 and the duty solenoid valve 255 are controlled based on the map.

When shifting from the low intake air amount region to the high intake air amount region, in a region where the engine speed R is low or the intake air amount Q is small, the intake relief valve 235 is open,
By opening the exhaust leak valve 230, the pre-rotation of the secondary turbocharger 206 is performed. When the engine speed reaches R2 or the intake air amount reaches the line Q2-R2, a solenoid-operated three-way valve 243 for controlling the intake relief valve 235 is used.
Turns ON, the intake relief valve 235 is closed, and then
Until the exhaust cut valve 223 opens, the secondary side blower 2
13 The pressure downstream increases. Then, when reaching the line of Q4-R4, a solenoid type three-way valve 2 for controlling the exhaust cut valve 223 is provided.
40 turns ON, the exhaust cut valve 223 opens, and then the Q6-R
When the line reaches 6 and the solenoid-operated three-way valve 238 for controlling the intake cut valve 232 is turned on and the intake cut valve 232 is opened, supercharging by the secondary turbocharger 206 starts. That is, the vehicle enters the supercharging region by both the primary and secondary turbochargers 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,
Since the atmospheric pressure, which is a pressure source for opening the valve, is supplied via the differential pressure detection valve 250, the actual opening of the intake cut valve 232 is delayed with respect to the operation of the solenoid 238. Therefore, the solenoid 238 for controlling the intake cut valve 232 is turned off.
The lines of Q6 and R6 to be turned on are set in consideration of the delay caused by the differential pressure detection valve 250, and as a result, the lines of Q6 and R6 are turned off from ON to Q4 of the solenoid 240 for controlling the exhaust cut valve 223. It is assumed to be close to the line of R4. Also, these Q6, R6 and Q4, R4 can be made to match.

Conversely, when shifting from the high intake air amount range to the low intake air amount region, each of the solenoid type three-way valves 238, 24 for controlling the intake cut valve 232, the exhaust cut valve 223, and the intake relief valve 235.
0, 243 is set to have a hysteresis so as to be switched at the lines Q5-R5, Q3-R3, Q1-R1, respectively, as shown by the broken lines in FIG. In other words, when shifting from the high intake air amount range to the low intake air amount region, when reaching the line of Q3, R3, the closing control of the exhaust cut valve 223 is performed. , The closing control of the intake cut valve 232 is performed, and after that, the opening control of the intake relief valve 235 is performed. Thus, the intake cut valve 2
Since the valve 32 closes later than the exhaust cut valve 223, the occurrence of surging when shifting to the low intake air amount region is prevented.

Further, in this embodiment, the line for turning ON / OFF the solenoid type three-way valve 245 for controlling the waste gate valve 227 is usually the ON / OFF line of the solenoid 240 for controlling the exhaust cut valve 223, Q4-R4, Q3-R3. Of each line.
That is, at the time of transition from the low intake air amount region to the high intake air amount region, the solenoid 245 is turned off from ON in the line Q4-R4. Also, when shifting from the high intake air amount region to the low intake air amount region, the solenoid 245 is turned on from the OFF line in the line Q3-R3.

Then, when it is determined that there is a request to shift from the low intake air amount range to the high intake air amount region, for example, when the throttle valve opening is increased by a predetermined amount or more, from before the opening operation of the exhaust cut valve 223, The wastegate valve 227 is forcibly closed for a predetermined period after the opening operation until the supercharging pressure reaches the set pressure according to the operation state. That is, when it is determined that the above-mentioned shift request has been made, the three-way valve 245 is turned off and the wastegate valve 227 is immediately closed. And the exhaust cut valve 2
When the supercharging pressure detected by the supercharging pressure sensor 257 reaches the set pressure, the three-way valve 245 is turned on to enable the wastegate valve 227 to operate.

In this case, the set pressure is changed in accordance with the operation state, that is, the set pressure is set lower as the transmission shift position is at a lower speed. This is because the lower the speed stage, the higher the engine speed and, consequently, the boost pressure, the faster the boost pressure. twenty two
It is intended to prevent overcharging by outputting an instruction to open 7.

The higher the engine acceleration, the lower the set pressure is set. The purpose is to prevent overcharging for the same reason as in the above case.

The set pressure when regular gasoline is supplied is set lower than the set pressure when high-octane gasoline is supplied. When regular gasoline is supplied, knocking is liable to occur. Therefore, the boost pressure is set to a low level to prevent knocking.

If the cooling water temperature of the engine is out of the proper temperature, the set pressure is set low. That is, since knocking is apt to occur when the engine is cold or when the engine is heated, the boost pressure is set to a low level to prevent knocking.

The set pressure is set low until the traveling distance of the vehicle reaches a predetermined distance. This is to suppress the supercharging pressure to a low level at the beginning of use in consideration of the fact that the supercharging pressure is reduced by aging.

In FIG. 3, the broken part of each line is on a so-called no-load line or load-load line.

Therefore, in the above embodiment, the introduction of exhaust gas to the secondary turbocharger 206 is stopped when the engine is in the low intake air amount range than the line Q6-R6,
Only the primary turbocharger 204 operates, and a high boost pressure can be obtained at a good rise. On the other hand, the engine
When the intake air amount range is higher than Q6-R6, both the primary turbocharger 204 and the secondary turbocharger 206 operate to obtain an appropriate supercharging pressure while securing the intake air flow rate.

Further, at the time of a request for transition from the intake air amount range to the high intake air amount region, the waste gate valve 227 closes for a predetermined period before the opening operation of the exhaust cut valve 223 until the supercharging pressure reaches the set pressure after the opening operation. Because the exhaust relief by this wastegate valve 227 is prohibited, the secondary turbocharger
The pressure of the exhaust gas supplied to 206 increases. Therefore, the rotation speed of the secondary turbocharger 206 quickly rises with good responsiveness, the drop in the supercharging pressure is reduced, and the occurrence of torque shock is prevented.

In this case, the set pressure is changed according to the shift position of the transmission, the acceleration of the engine, the type of fuel, the temperature of the cooling water of the engine, and the mileage of the vehicle. Problems such as prevention of supercharging, prevention of occurrence of knocking, and prevention of reduction of supercharging pressure due to aging are avoided.

FIG. 5 shows the relationship between the solenoid operating state of each valve and the transition of the operating state based on the characteristic diagram of FIG. 4 described above (the left side of the horizontal axis is a low intake air amount area, and the right side is a high intake air amount area). Is what I saw in As can be seen from this figure, the hysteresis of the opening and closing operation of the exhaust cut valve 223 is completely included in the hysteresis of the opening and closing operation of the intake cut valve 232. The intake cut valve 23
(2) Even if the control solenoid 238 is turned on at Q6 and R6, the actual opening operation of the intake cut valve 232 is delayed by the action of the differential pressure detection valve 250 as shown by the broken line in FIG. So this
Q6 and R6 are Q4 and R4 of the exhaust cut valve 223 opening control as described above.
And the same line or the same line. On the other hand, the closing operation of the intake cut valve 232 does not involve the delay as described above with respect to the operation of the solenoid 238, so that the setting lines Q5 and R5 need to satisfy Q5 <Q3 and R5 <R3. .

Next, control of each valve based on the characteristics of FIG. 4 will be described with reference to the control circuit of FIG. The solenoid 243 for operating the intake relief valve is operated by the output of the first OR circuit 121 which receives the output of the first comparison circuit 111 shown at the top of the figure and the output of the second comparison circuit 112 shown below. Controlled. Here, the first comparison circuit 111 compares the intake air amount Q which is a detection signal of the air flow meter 221 with the output value of the first addition circuit 131 which is a reference value. Then, the first adder circuit 131 is set value Q ₁ is input corresponding to Q ₁ line of FIG. 4, also, 'a value of ₁ (however, Q ₁ + Q' Q for the Q _{1 1} = Q ₂ ) is input through the first gate 141, and when the first gate 141 is opened, the first comparison circuit 111 uses Q ₁ + Q ′ ₁ = Q ₂ as a reference value. output, also when the first gate 141 is closed to output the first comparison circuit 111 to Q ₁ as the reference value. The first gate 141 is opened and closed by the output of the first OR circuit 121.

The second comparing circuit 112 compares the engine speed R detected by the engine speed sensor with the output value of the second adding circuit 132 which is a reference value. Second adding circuit 132, the setting value R ₁ corresponding to R ₁ line of FIG. 4 is input, also 'value of ₁ (wherein, R ₁ + R' R for the R _{1 1} = R ₂₎ is When the second gate 142 is opened, the second comparison circuit 112 is configured to use R ₁ + R ′ ₁ = R ₂ as a reference value.
Output to, also, when the second gate 142 is closed to output the second comparison circuit 112 to R ₁ as a reference value. 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 amount Q and the detected engine speed R with respective reference values which are outputs of the first and second addition circuits.
When Q or R exceeds the reference value, an ON signal is output to the intake relief valve actuating solenoid 243 (when ON, the intake relief valve 235 is closed). First and second gates 14
Reference numerals 1 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, at the time of transition from the low intake air amount region to the high intake air amount region, since the output signal of the first OR circuit 121 is OFF, the gates 141 and 142 are opened and the first and second comparison circuits 111 and 112 are opened.
, Q ₂ and R ₂ are input as reference values. Therefore, the fourth
In the figure, when the line reaches Q ₂ and R ₂ , an ON signal is issued and the intake relief valve 235 is opened. In addition, the first and second gates 141 and 142 are closed by this ON signal, whereby the reference values of Q and R become Q1 and R1, respectively. That is, the line is set with the hysteresis corresponding to Q ′ ₁ and R ′ ₁ in preparation for the transition in the reverse direction.

The exhaust cut valve operating solenoid 240 is also controlled by a similar control circuit. That is, a third comparison circuit 113 is provided for the intake air amount Q, and a fourth comparison circuit 114 is provided for the engine speed R. The outputs of these comparison circuits 113 and 114 are provided by a second OR circuit 122. Through the solenoid
Sent to 240. A third adding circuit 133 is provided for the third comparing circuit 113, and a fourth adding circuit 133 is provided for the fourth comparing circuit 114.
Are similarly provided. Then, the set value Q ₃ is input to the third adder 133, and Q ′ ₃ (Q ₃ + Q ′ ₃ = Q ₄ ) is input via the third gate 143. Similarly, the fourth adder 134 has a set value R
₃ and R ′ ₃ via the fourth gate 144 (where R ₃ + R ′ ₃
= R ₄ ) is input. Similarly, the set value R ₃ and R ′ ₃ (where R ₃ + R ′ ₃ = R ₄ ) via the fourth gate 144 are input to the fourth adder circuit 134. This circuit operates in the same manner as the above-described first and second comparison circuits, so that the exhaust cut valve 223 opens based on the lines Q ₄ and R _{4 in} FIG. 4 when shifting to the high intake air amount region. Activated and also
During the transition to low intake air amount area Q _3, the valve by R ₃ lines
223 is closed.

For the solenoid 238 for operating the intake cut valve, the fifth
And the outputs of the sixth comparison circuits 115 and 116 are connected to a third OR circuit 123
A similar control circuit is provided which supplies via The control circuit has a fifth circuit for each of the comparison circuits 115 and 116.
And sixth adder circuits 135 and 136, and fifth and sixth gates 145 and 146 for each adder circuit 135 and 136. The basic operation is not different from the circuit for each valve. In other words, when shifting to the high intake air amount range, the intake cut valve opening control is performed by the lines of Q ₆ and R ₆ ,
When shifting to the low intake air amount range, the intake cut valve closing control is performed by the lines of Q ₅ and R ₅ . Here, Q ₆ and R ₆ is set similarly in the form of _{Q 5 + Q '5 = Q} 6, R 5 + R' 5 = R 6.

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 the gate 147. Then, the second valve for operating the exhaust cut valve is used.
A timer 150 is provided that starts counting up when the output of the OR circuit 122 changes from ON to OFF, and
When the count value of the timer 150 exceeds a set value (for example, a value corresponding to 2 seconds), a seventh comparison circuit 11 that issues an ON signal
When an ON signal is output from the seventh comparison circuit 117, 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 R are set. To
It is configured to change to Q ₆ and R ₆ and to reset the timer 150. Once the seventh gate 147 is closed, the output of the seventh comparison circuit 117 is turned off, but the reference value of the switching line is changed to Q ₆ and R ₆ as described above. Therefore, the solenoid for operating the intake cut valve 23
8 is held in the closed operating state. This prevents surging caused by the exhaust cut valve solenoid 238 being in the OFF state and the intake cut valve solenoid 240 being in the ON state for a long time when shifting to the low intake air amount range.

Next, a circuit for controlling the wastegate valve 227 will be described. Reference numeral 120 denotes a tenth comparison circuit, to which the output signal of the throttle sensor 258 is input. The comparison circuit 120 determines whether the output signal of the throttle sensor 258 has exceeded a set value. And
When it is determined that the set value has been exceeded, it is determined that a request to shift from the low intake air amount range to the high intake air amount region has been made, and an ON signal is supplied to the wastegate valve solenoid 245 until the exhaust cut valve 223 opens. Continue to output the wastegate valve 2
Close 27.

Also, reference numeral 118 denotes an eighth comparison circuit.
Is supplied with the output signal of the OR circuit 122. The comparison circuit 118 determines whether the output signal of the OR circuit 122 has changed from “ON to OFF” or “OFF to ON”. Then, when the output signal of the OR circuit 122 changes from OFF to ON,
In other words, when the exhaust cut valve 223 is switched from the closed operation to the open operation, an ON signal is output to the waste gate valve solenoid 245 after the exhaust cut valve 223 is opened until the supercharging pressure reaches a set pressure according to the operation state. Then, the wastegate 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 is switched from the open operation to the closed operation, it is opened without outputting an ON signal to the waste gate valve solenoid 245. In advance, the operation of the wastegate valve 227 is permitted. Specifically, a normally open eighth gate 148 is connected to the comparison circuit 118, and an output signal of the gate 148 is input to a waste gate valve solenoid 245. On the other hand, a ninth comparison circuit 119 receives the output of the supercharging pressure sensor 257, and when the supercharging pressure exceeds the set pressure, the gate 148 is connected to the gate 1
A signal to close 48 is output. Here, the set pressure is changed by the outputs of the various sensors 259, 260, 281, 282. Therefore, the output signal of the OR circuit 122 is turned off.
When the state changes from ON to ON, the ON signal is output from the comparison circuit 118 and the wastegate valve 227 is closed. Thereafter, when the supercharging pressure exceeds the set pressure and the gate 148 is closed, the ON signal to the wastegate valve solenoid 245 is output. Is shut off, and the operation of the wastegate valve 227 is permitted.

In the above configuration, operating state detecting means for detecting the operating state of the engine by the sensors 259, 260, 281 and 282
301. Further, the output of the operating state detecting means 301 and the supercharging pressure sensor (supercharging pressure detecting means) 257 is received from the comparison circuit 118 by a circuit on the subsequent stage, and a request for shifting from the low intake air amount range to the high intake air amount region is received. In some cases, the wastegate valve (supercharging pressure adjustment) is performed so as to increase the supercharging pressure for a predetermined period from before the opening operation of the exhaust cut valve 223 until the supercharging pressure reaches a set pressure according to the operation state after the opening operation. Means) 227
Pressure control means 302 for controlling the pressure.

In the above embodiment, the wastegate valve 227 is used as a boost pressure adjusting means, and the wastegate valve 227 is closed to increase the boost pressure. However, the boost pressure may be increased by various other methods. Is possible. For example, in the case of a fuel injection type engine, the fuel injection amount adjusting device may be a boost pressure adjusting means, and the boost pressure may be increased by increasing the fuel injection amount. Further, the ignition timing adjusting device may be a boost pressure adjusting means, and the ignition timing may be advanced to increase the boost pressure.

Further, although the rotary piston engine has been described in the above embodiment, the present invention is not limited to this. For example, the present invention can be applied to a control device of another type of turbocharged engine such as a reciprocating engine. it can.

(Effects of the Invention) As described above, according to the control apparatus for a turbocharged engine of the inventions of claims 1 to 6, a plurality of exhaust turbochargers are arranged in parallel in the intake passage. At least one exhaust turbocharger is used as a secondary turbocharger, and an exhaust cutoff valve is provided in an external air passage dedicated to the secondary turbocharger, and the exhaust cutoff valve is opened only in a high intake air amount range of the engine. Since the turbocharger is operated, and at the time of a request for shifting from the low intake air amount range to the high intake air amount region, the supercharging pressure is increased so that the supercharging pressure becomes the set pressure according to the operation state. In addition to ensuring a high boost pressure in the low intake air volume range, it is possible to obtain the basic effect of obtaining an appropriate boost pressure while securing the intake flow rate in the high intake air volume range, and a low intake air volume range. To shift from air to high intake air volume At this time, while avoiding problems such as occurrence of knocking due to overcharging, for example, the pressure of exhaust gas supplied to the secondary turbocharger is increased to increase the rotation speed of the secondary turbocharger quickly with good responsiveness, It is possible to alleviate the drop in the supply pressure and prevent the occurrence of torque shock.

[Brief description of the drawings]

FIG. 1 is a diagram showing the configuration of the present invention. 2 to 6 exemplify an embodiment of the present invention, and FIG.
FIG. 3 is a cross-sectional view of the differential pressure detecting valve, FIG. 4 is a map diagram showing an operation region of each valve, FIG. 5 is an explanatory diagram for explaining the operation of each valve, and FIG. 6 is a control circuit diagram. 204 ... Primary turbocharger 206 ... Secondary turbocharger 223 ... Exhaust cut valve 227 ... Waste gate valve (Charging pressure adjusting means) 257 ... Charging pressure sensor (Charging pressure detecting means) 301 ... Operating state detecting means 302 ... Supercharging pressure control means

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Seiji Tajima 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (56) References JP-A-61-164040 (JP, A) JP-A-59 -145328 (JP, A) Fully open Showa 61-198529 (JP, U) Fully open Showa 60-145232 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F02B 33/00- 39/16

Claims (6)

(57) [Claims] A plurality of exhaust turbochargers are arranged in parallel in an intake passage, and at least one of the exhaust turbochargers is used as a secondary turbocharger, and an exhaust passage dedicated to the secondary turbocharger is provided. An exhaust cut valve is installed in the turbocharger engine that opens the exhaust cut valve only in the high intake air amount range of the engine to operate the secondary turbocharger. Detecting means, supercharging pressure adjusting means for adjusting the supercharging pressure, supercharging pressure detecting means for detecting the supercharging pressure, receiving the output of the operating state detecting means and the supercharging pressure detecting means, At the time of a request for transition from the region to the high intake air amount region, the boost pressure is increased for a predetermined period from before the opening operation of the exhaust cut valve until the boost pressure reaches a set pressure according to the operating state after the opening operation. Above the boost pressure adjustment A turbocharger-equipped engine control device, comprising: a supercharging pressure control means for controlling a regulating means. 2. The control device for an engine with a turbocharger according to claim 1, wherein the set pressure is changed according to an operation state. 3. The control device for an engine with a turbocharger according to claim 2, wherein the set pressure is set lower as the shift position of the transmission is lower. 4. The control device for a turbocharged engine according to claim 2, wherein the set pressure is set lower as the acceleration of the engine is higher. 5. The control device for a turbocharged engine according to claim 2, wherein the set pressure is set lower when regular gasoline is supplied than when high-octane gasoline is supplied. 6. An exhaust turbo-type first supercharger operating at least in a low flow rate region of an intake air amount and a second exhaust turbo type supercharger operating in a high flow rate range are arranged in parallel. In the turbocharged engine, a first exhaust passage in which a turbine of the first supercharger is provided, a second exhaust passage in which a turbine of the second supercharger is provided, (2) an exhaust cut valve for opening and closing an exhaust passage; a first intake passage in which a blower of the first supercharger is provided; and a second intake passage in which a blower of the second supercharger is provided. An intake cut valve for opening and closing a second intake passage downstream of the blower of the second supercharger; an operating state detecting means for detecting an operating state of the engine; Open the exhaust cut valve and intake cut valve in the high flow rate region of Switching control means for switching the supercharger from a non-operation state to an operation state, a wastegate valve for adjusting a supercharging pressure to a predetermined pressure, a supercharging pressure detecting means for detecting a supercharging pressure, and the operating state detecting means And boost pressure control means for receiving the output of the boost pressure detection means and controlling the waste gate valve so as to increase the boost pressure when a request to shift the intake air amount from the low flow rate area to the high flow rate area is provided. A control device for an engine with a turbocharger, characterized in that: