JPH03156125A - Exhaust control device of engine with turbo superchager - Google Patents

Abstract

PURPOSE:To reduce the change of a supercharging pressure so as to enable the reducing of a torque shock by adjusting the supercharging pressure for a determined pressure when an engine accelerates, and correcting the determined pressure lower the larger the acceleration is. CONSTITUTION:A secondary turbo supercharger 206 operates by installing an exhaust cut valve 223 in an exhaust passage 203 for exclusive use of the secondary turbo supercharger 206, and opening the exhaust cut valve 223 only in the range of a high sucked air amount of an engine 201. A control unit 246 is given an output by a throttle sensor and shift sensor 259 which detect the opening of a throttle valve 216, and controls an exhaust leakage valve 230 in order to adjust a supercharging pressure for a determined pressure when the engine 201 accelerates and to correct the determined pressure lower the lower speed stage a shift position is. This restrains a high pressure supply from going down due to the delayed response, etc., of the secondary turbo supercharger 206 when the exhaust cut valve 223 opens, and enables the reducing of a torque shock.

Description

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

(Prior Art) Conventionally, as disclosed in Utility Model Application Publication No. 1-17832Q, this type of turbocharged engine has been equipped with primary and secondary exhaust turbocharger turbines in the exhaust passage. are installed in parallel, and the blowers of these two exhaust turbo superchargers are connected to the intake passage of the engine, and an energy cut valve is installed in the exhaust passage upstream of the turbine of the secondary turbo supercharger to set the intake air amount. When the amount is less than the specified value, the exhaust cut valve is closed to disable the secondary turbocharger, and exhaust gas from the exhaust passage is intensively supplied to the turbine of the primary turbocharger to maintain high boost pressure. When the amount of intake air is greater than the set value, the exhaust cut valve is opened to operate the secondary turbo supercharger, and the exhaust gas from the exhaust passage is supplied to the turbines of the two exhaust turbo superchargers to reduce the amount of intake air. A system is known in which an appropriate boost pressure is maintained while maintaining the proper boost pressure.

(Problem to be Solved by the Invention) In such a turbocharged engine, if the exhaust cut valve opens during engine acceleration and the secondary turbocharger switches from inoperable to active, ■ Even if exhaust gas is supplied to the secondary turbocharger, which has been at a standstill, it will take time for that turbocharger to reach the speed at which supercharging is possible. Exhaust gas that was previously supplied centrally is now diverted not only to the primary turbocharger but also to the secondary turbocharger.
Due to reasons such as a temporary lack of supercharging capacity of the primary turbo supercharger, there is a problem in that the torque drops due to the lack of supercharging capacity, resulting in torque shock.

Incidentally, in such a turbocharged engine, there are, for example, the following devices that have a function of adjusting the supercharging pressure of the supercharger.

(a) An exhaust leak passage that bypasses the exhaust cut valve is provided in the exhaust passage, and an exhaust leak valve is provided in the exhaust leak passage, so that when transitioning from a low intake air amount area to a high intake air amount area,
Immediately before the transition, the exhaust leak valve is opened to guide a portion of the exhaust gas supplied to the turbine of the primary turbocharger to the turbine of the secondary turbocharger. According to this system, the supercharging pressure is adjusted to the set pressure using exhaust relief, and the exhaust gas runs up the secondary turbo supercharger to provide pre-rotation, allowing the secondary turbo supercharger to operate in a high intake air amount range. You can improve your rise.

(b) A wastegate passage that bypasses the turbine of the supercharger is provided in the exhaust passage, a wastegate valve is provided in the wastegate passage, and the wastegate valve is opened to allow the exhaust gas to be supplied to the turbine of the supercharger. This is to adjust the supercharging pressure to the set pressure by relieving the part.

Both the exhaust leak valve and the wastegate valve function as a supercharging pressure adjusting means that adjusts the supercharging pressure of the supercharger for one week.

The present invention has been made with attention to these points,
The purpose of this is that when the secondary turbocharger switches from inoperation to operation during engine acceleration, overcharging is performed using a boost pressure adjustment means such as an exhaust leak valve or a wastegate valve. The purpose is to reduce supply pressure fluctuations and suppress torque drop.

(Means for Solving the Problems) In order to achieve the object described above, in the present invention, the supercharging pressure is adjusted to a set pressure by a supercharging pressure adjusting means such as an exhaust leak valve or a waste gate valve I, and the engine The higher the acceleration, the lower the set pressure is corrected.

Specifically, the +:l/) solution of the present invention is to arrange a plurality of superchargers including an exhaust turbo supercharger in parallel in the intake passage, and at least one of the exhaust turbo superchargers As a secondary turbo supercharger, an exhaust cut valve is installed in the exhaust passage exclusively for 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 an engine with a turbocharger. In response to this, a supercharging pressure adjusting means for adjusting the supercharging pressure of the supercharger, an acceleration detecting means for detecting the acceleration of the engine, and an output of the acceleration detecting means are received, and the supercharging is performed when the engine is accelerated. The supercharging pressure adjusting means is provided with a control means for adjusting the boost pressure to a set pressure and correcting the set pressure to a lower value as the acceleration of the engine increases.

Here, specifically, the acceleration detection means is means for detecting an acceleration request instructed to the engine, and in response to this, the control means receives the output of the acceleration detection means and instructs the engine to accelerate. The supercharging pressure adjusting means may be controlled so as to adjust the supercharging pressure to a set pressure when the acceleration request is made, and to correct the set pressure to a lower value as the acceleration request instructed to the engine becomes larger.

Furthermore, shift position detection means for detecting the shift position of the transmission may be provided.

In response to this, the control means receives the outputs of the acceleration detection means and the shift position detection means, adjusts the boost pressure to the set pressure when the engine accelerates, and corrects the set pressure to be lower as the shift position is lower. The supercharging pressure adjusting means may be used as a means for controlling the supercharging pressure adjusting means.

Further, the control means receives the output of the acceleration detection means, adjusts the boost pressure to a set pressure when the engine accelerates, and temporarily corrects the set pressure to a lower value when the engine acceleration is large. It may also be a means for controlling the adjustment means.

Further, the control means receives the output of the acceleration detection means, adjusts the boost pressure to a set pressure when the engine accelerates, and adjusts the boost pressure so as to constantly correct the set pressure to a lower value when the engine acceleration is large. It may also be a means for controlling the adjustment means.

(Function) With the above configuration, in the present invention, the secondary turbocharger becomes inactive in the low intake air amount region, and exhaust gas is intensively co-fed to the superchargers other than the secondary turbocharger. In the high intake air flow range, the secondary turbocharger operates and exhaust gas is supplied to both exhaust turbochargers, ensuring proper supercharging while ensuring the intake flow rate. pressure is obtained.

Then, when the engine is accelerated, the supercharging pressure adjusting means is controlled by the control means based on the detection by the acceleration detecting means, and the supercharging pressure is adjusted to the set pressure when the engine is accelerating.
The boost pressure drops to this set pressure before the exhaust cut valve opens. Therefore, a drop in supercharging pressure caused by a delay in the response of the secondary turbocharger or a temporary decrease in the supercharging capacity of the primary turbocharger when the exhaust cut valve is opened is suppressed, and torque shock is reduced.

In that case, the larger the engine acceleration, the larger the drop in boost pressure will be, but the control means will correct the above set pressure to a lower value as the engine acceleration increases, so the boost pressure will always be maintained regardless of the value of the engine acceleration. This suppresses the drop in torque and reduces torque shock.

Here, specifically, the acceleration detection means is a means for detecting an acceleration request instructed to the engine, and the control means receives the output of the acceleration detection means and instructs the engine to accelerate. B1. If the supercharging pressure is adjusted to the set pressure in 'I, and the boost pressure adjustment means is controlled so that the greater the acceleration request instructed to the engine, the lower the set pressure 11 is, then the actual acceleration will be In this case, the process by the control means is started even before the person becomes deaf, and the boost pressure is quickly adjusted.

Furthermore, shift position detection means for detecting the shift position of the transmission is provided, and the control means receives the outputs of the acceleration detection means and the shift position detection means, and adjusts the supercharging pressure to the set pressure when the engine is accelerated. If the shift position is controlled by a supercharging pressure adjustment means that corrects the set pressure to a lower value as the gear position becomes lower, the set pressure will be corrected lower as the engine speed rises faster in the lower gears, thereby reducing the pressure during acceleration. Torque shock is reduced.

In this case, the lower the speed, the more the boost pressure will decrease, but the lower the speed, the less driving force is required from the engine, and the engine output has more margin, so the drop in boost pressure will reduce acceleration. etc. will not occur.

Furthermore, the control means receives the output of the acceleration detection means, adjusts the supercharging pressure to a set pressure when the engine accelerates, and temporarily compensates for the set pressure by increasing the set pressure when the engine accelerates. When the pressure adjustment means is used as a control means, the reduction in supercharging pressure is reduced because the correction process is temporary.

The control means receives the output of the acceleration detection means, and adjusts the boost pressure to a set pressure when the engine accelerates, and constantly corrects the set pressure to a lower value when the engine acceleration is large. When the means is used as a controlling means, the torque shock reduction function during acceleration becomes greater because the correction process is steady.

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

FIG. 1 shows a vehicle equipped with an exhaust control device according to an embodiment of the present invention.
This figure shows an 0-ta type rotary piston engine with a turbo supercharger. In FIG. 1, 201 is an engine, a transmission 208 is connected to the engine 1, and the transmission 208 has a shift sensor 259 as a shift position detection means for detecting a shift position.
is provided. Exhaust passages 202 and 203 of each cylinder are provided independently of each other. A turbine 205 of a primary turbocharger 204 is disposed in one of these two exhaust passages 202 and 203, and a turbine 207 of a secondary turbocharger 206 is disposed in the other. That is, in this engine 201, the exhaust passage 202,':)Q3 of each cylinder is independently connected to both the primary and secondary exhaust turbo superchargers 204, 20.
By guiding the exhaust gas to the turbines 205 and 207 of No. 6, the exhaust dynamic pressure is effectively applied to both the turbines 205 and 207 in the region where supercharging is performed by the two exhaust turbo superchargers 204 and 206, thereby improving supercharging efficiency. I have to. 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 blower 213 of the secondary turbo supercharger 206 is installed. These branch passages 210° and 212 are formed so as to face each other at the branching portion and extend substantially straight on both sides. Also,
The two branch passages 210 and 212 are connected to each blower 211°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 it, and a throttle valve 216 is disposed between the intercooler 214 and the surge tank 2150. has been done. Further, the downstream end of the intake passage 209 branches into two independent intake passages 217 and 218 corresponding to each cylinder of the engine 201, and is connected to each intake port (not shown). Each of these independent intake passages 217 and 218 has a fuel injection valve 219,
220 are arranged.

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

The two exhaust passages 202, 203 are communicated with each other by a relatively small diameter communication passage 222 upstream of both the primary and secondary turbochargers 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 wastegate passage 225 is formed which extends from the middle of the communication passage 222 and communicates with the combined exhaust passage 224 downstream of the turbine 205 207.
5 is provided with a wastegate valve 227 to which a diaphragm type actuator 226 is linked. A leakage passage 228 is formed that communicates the upstream part of the wastegate valve 227 in the wastegate 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 driven by a diaphragm type actuator 2.
33. Further, a relief passage 234 is formed in the branch passage 212 on the secondary side so as to bypass the blower 213.
4 is provided with a diaphragm type intake relief valve 235.

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

When the pressure on the downstream side of the blower 211 becomes equal to or higher than the set pressure, the actuator 229 is operated to open the exhaust leak valve 230, thereby causing the exhaust cut valve 22 to open.
3 is closed, a small amount of exhaust gas leaks through the passage 22
8 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. This exhaust leak valve 230 is connected to the primary turbo supercharger 20.
4 and the secondary turbocharger 206.

The conduit 236 is connected to the branch passage 210 upstream of the blower 211 via a conduit 255. The conduit 255 is provided with a duty solenoid valve 256 that corrects the set pressure of the exhaust leak valve 230. By adjusting the duty ratio of the duty solenoid valve 256, the operating characteristics of the wastegate valve 227 and the exhaust leakage valve 230 are changed. That is, by adjusting the duty ratio, as shown in Table 1 below, the lower the shift position of the transmission 208, the lower the set pressure (supercharging pressure; mmHg), which is the target value controlled by the exhaust leak valve 230, is corrected. That's what I do.

Table 1 The above actuator 23 that operates the intake cut valve 232
The pressure chamber No. 3 is connected to an output port of an electromagnetic solenoid type three-way valve 238 by a conduit 237. Further, the actuator 231 that operates the exhaust cut valve 223 is
Another three-way valve 240 of the electromagnetic solenoid type is connected to the conduit 239.
connected to the output port of the Furthermore, the pressure chamber of the actuator 241 that operates the intake relief valve 235 is
Another three-way valve 243 of electromagnetic solenoid type is connected to the conduit 242.
connected to the output port of the 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 lively 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 7u magnetic solenoid type three-way valves 238, 240.
243, 245, duty solenoid valve 25
6 and the two fuel injection valves 219 and 220 are controlled by a control unit 246 configured using a microcomputer. control unit 2
46 includes an output signal of an engine rotation speed sensor that detects the rotation speed of the engine 201, an output signal of an air flow meter 221 that detects the intake air amount of the engine 201, and a shift sensor 25 that detects the shift position of the transmission.
In addition to the output signal of 9, the output signal of the throttle sensor that detects the opening degree of the throttle valve 216, the output signal of the boost pressure sensor that detects the boost pressure P1 downstream of the primary side blower 211, etc. are manually input, and these signals are input manually. Based on this, control as described below is performed. The upper throttle sensor functions as an acceleration detection means for detecting the acceleration of the engine 201.

Further, the shift sensor 259 functions as a shift position detection means for detecting the shift position of the transmission.

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 negative pressure tank 248 via a conduit 247.
49 to the output port 27 of the differential pressure detection valve 250, which will be described later.
Connected to 0.

Intake negative pressure downstream of the throttle valve 216 is introduced into the negative pressure tank 248 via a check valve 251. Furthermore, one input port of the three-way valve 240 for controlling the exhaust gas cut valve is open to the atmosphere, and the other human-powered boat is
It is connected via a conduit 252 to the conduit 247 which is connected to the negative pressure tank 248 . On the other hand, one input 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, waste gate valve 227
One input port of three-way control valve 245 is open to the atmosphere, and the other input port is connected to conduit 236 by conduit 254 .

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

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

The second input port 269 is also connected upstream of the intake cut valve 232 by a conduit 274, so that the second input port 269 is connected upstream of the intake cut valve 232 when the intake cut valve 232 is closed.
The upstream pressure P2 is introduced. Pressures Pi and P introduced from these two power ports 267 and 269
2 (P2PI) exceeds a predetermined value, the valve body 272
opens the output capo-1-270. This output port 270 is connected via a conduit 240 to one of the manual ports of the three-way valve 238 for controlling the intake cut valve 2B2. Therefore, the three-way valve 238 is turned on and the intake cut valve 2-J,
2. With the conduit 237 connected to the pressure chamber of the operating actuator 233 communicating with the conduit 249 connected to the output port of the differential pressure detection valve 250, the pressure upstream of the intake cut valve 232, that is, the secondary side supercharging pressure P2 approaches the primary side supercharging pressure P1, and the differential pressure PL-
When P2 disappears and the differential pressure P2-PI becomes larger than a predetermined value, the atmosphere is introduced into the actuator 233 and the intake cut valve 232 is opened. In addition, the three-way valve 23
8 is turned off and the conduit 237 on the actuator 233 side is communicated with the conduit 247 connected to the negative pressure tank 248, negative pressure is supplied to the actuator 233 and the 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 ON, the primary side blower 2
11, and when the pressure downstream of this blower exceeds a predetermined value, an actuator 226 operates to open a wastegate valve 227 to relieve exhaust gas and optimize boost pressure characteristics. . Also, this three-way valve 24
When valve 5 is OFF, it is released to the atmosphere and the waste gate valve 2
27 closes.

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

When transitioning from a low intake air amount region to a high intake air amount region, the intake relief valve 235 is open in a region where the engine speed R is low or the intake air mQ is small.
Pre-rotation of the secondary turbocharger 206 is performed by opening the exhaust leakage valve 230.

Then, the engine speed is R2 or the intake air amount is Q.
When the line 2-R2 is reached, 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 cut valve 22 is closed.
3 opens, the pressure downstream of the secondary blower 213 increases.

When the Q4-R4 line is reached, the solenoid type three-way valve 240 for controlling the exhaust cut valve 223 is turned ON and the exhaust cut valve 223 is opened, and then the Q6-R6 line is reached, and the solenoid type three-way valve 240 for controlling the exhaust cut valve 223 is turned on. When the solenoid type three-way valve 238 is turned on and the intake cut valve 232 is opened, supercharging by the secondary turbo supercharger 206 starts. In other words, the engine enters the supercharging region using both the primary and secondary superchargers at the Q6-R6 line. Note that the actuator 233 that drives the intake cut valve 232 is not controlled only by the operation of the solenoid 2138, 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 2
32 Turning the control solenoid 238 from OFF to ON Q6. The R6 line is set in consideration of the delay caused by the differential pressure detection valve 250, and as a result, the Q6. The R6 line is connected to Q4 when the exhaust cut valve 223 control solenoid 240 turns from OFF to ON. It is assumed that the line is close to the line R4. Also, these Q6°R6 and Q4. 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. Third
Q5-R5 and Q3-R3, respectively, as shown by broken lines in the figure.
, Ql-R1. 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
23 close control is performed, and then the state shifts to the low intake air amount region and Q5. When the R5 line is reached, the intake cut valve 232
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.

Also, in this embodiment, the solenoid type three-way valve 245 for controlling the waste gate valve 227 is turned on.

The lines to be turned off are Q4-R4 and Q3, which are the ON and OFF lines for the exhaust cut valve 223 control solenoid 240.
- Match each line of R3.

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. Further, when transitioning from the high intake air amount region to the low intake air amount region, the solenoid 245 is turned on from OFF after a predetermined time has passed after crossing the line Q3-R3.

Incidentally, in FIG. 10, 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 turbocharger 206 is stopped, so only the primary turbocharger 204 is activated. As a result, high boost pressure can be obtained quickly. On the other hand, when the engine is in a higher intake air amount region than the above line Q6-R6, both the primary turbo supercharger 204 and the secondary turbo supercharger 206 operate to ensure the intake flow rate and maintain appropriate supercharging pressure. You will get it.

When the engine 201 accelerates, the exhaust leak valve 230 is controlled based on the output signal of the throttle sensor.
Since the boost pressure is adjusted to the set pressure, the exhaust cut valve 22
3 opens, the supercharging pressure drops to this set pressure. Therefore, when the exhaust cut valve is opened, the secondary turbo supercharger 206
A drop in supercharging pressure caused by a delay in response, a temporary decrease in the supercharging capacity of the primary turbocharger 204, etc. is suppressed, and torque shock is reduced. Further, the secondary turbocharger 206 runs up and pre-rotates due to the exhaust gas, and the start-up of the secondary turbocharger 206 in a high intake air amount region is improved.

In other words, the conventional system shown by the dashed line in FIG. This causes a drop in boost pressure, which causes torque shock. On the other hand, what is shown by the solid line in the same figure is that of the above embodiment, but the supercharging pressure is lowered by the relief of the M air leak valve 230 before the exhaust cut valve 223 opens, and the exhaust cut valve 223 Even after opening, the boost pressure hardly decreases, and in the end, the drop in boost pressure is almost suppressed and there is no torque shock.]
Karu.

In that case, the larger the acceleration of the engine 201 is, the larger the drop in the boost pressure will be. However, the larger the acceleration of the engine 201 is, the lower the set pressure is corrected, so the boost pressure is always maintained regardless of the value of the acceleration of the engine 201. This suppresses the drop in torque and reduces torque shock.

At this time, the lower the speed stage, the greater the amount of decrease in boost pressure, but the lower the speed stage, the less driving force is required of the engine 201, and there is a margin in engine output, so the acceleration performance due to the decrease in boost pressure is reduced. No deterioration occurs.

Here, as the acceleration detection means, instead of using a throttle sensor as in the above embodiment, a means for detecting an acceleration request directed to the engine 201, such as an accelerator sensor that detects the amount of depression of an accelerator pedal, is used. You can. In this way, control of the exhaust leakage valve 230 is started before the engine actually enters the acceleration state, and the :1B adjustment of the supercharging pressure is quickly performed.

Further, in the above embodiment, when the engine 201 accelerates, the exhaust leak valve 230 continuously performs the boost pressure control;
In other words, since control is executed to constantly correct the set pressure to a lower value, the torque shock reduction function during acceleration is increased to the extent that the correction process is steady. However, instead of constantly correcting the set pressure to a low value in this way, as shown by the broken line in FIG. 6, the set pressure may be temporarily corrected to a low value when the acceleration of the engine 201 is large. good.

The timing is just before the exhaust cut valve 223 opens. In this way, since the correction process is temporary, the decrease in supercharging pressure before the exhaust cut valve 223 opens is reduced.

Further, in the above embodiment, the exhaust leak valve 230 is used as a supercharging pressure adjusting means, but the waste gate valve 227 may be used as a supercharging pressure adjusting means.

Figure 4 shows the relationship between the solenoid operating states of the six valves and the transition of operating states (the left side of the horizontal axis is the low intake air m range, and the right side is the high intake air amount range) based on the characteristic diagram in Figure 3 above. This is what I saw. As can be seen from this figure, the hysteresis of the opening/closing operation of the exhaust cut valve 223 is completely included in the hysteresis of the opening/closing operation of the intake cut valve 232. Note that the solenoid 238 for controlling the intake cut valve 232 is connected to the Q6. Even if R6 is turned ON, 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, this Q6. As described above, R6 is a line close to or the same line as 04°R4 for controlling the opening of the exhaust cut valve 223.

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 is Q5. R5 is Q5<Q3. R5<
It is necessary to set it to R3.

Next, control of the six valves based on the characteristics shown in FIG. 3 will be explained using the control circuit shown in FIG. 5. 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 mQ, 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. 3, and a value Q' + (however, Q+
Q'I-Q! ) is input through the first gate 141, and when the first gate 141 is opened, the first
output to the comparison circuit 111, and also outputs to the first gate 141
When closed, Ql is output to the first comparison circuit 111 as a reference value. And this 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 revenge circuit 132, which is the M'A value. The second p adding circuit 132 is manually inputted with a set value R1 corresponding to the R1 line in FIG.
The configuration is such that the values (R, +R', -R,) are input manually through the second gate 142, and when the second gate]42 is opened, the values R, +R', -R, -R
) is output to the second comparator circuit 112 as a value,
Furthermore, when the second gate 142 is closed, R is output as the base chain to the second comparison circuit 112. The second gate 142 is also opened and closed by the output of the first OR circuit 12].

The first and second comparison circuits 111 and 112 compare the detected intake air mQ and engine rotation speed R with respective reference values that are the outputs of the first and second addition circuits, and determine whether Q or R is When the value exceeds the reference value, an ON signal is output to the intake relief valve operating solenoid 243 (
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
Qco, R, are input as reference values. therefore,
When the lines Q, , R, in FIG. 3 are reached, 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, 142, so that the reference values of Q and R become Ql and R1, respectively. In other words, the line is set with hysteresis corresponding to Q'1 and R'l in preparation for a transition in the opposite direction.

The exhaust cut valve actuation solenoid 240 is also controlled by a similar control circuit. In other words, the third comparison circuit 113 also detects the engine rotation speed R with respect to the intake air mQ.
A fourth comparison circuit 114 is provided for this, and the outputs of these comparison circuits 113 and 114 are sent to the solenoid 240 via the second OR circuit 122. Third comparison circuit 1
Similarly, a third addition circuit 133 is provided for 13, and a fourth addition circuit 134 is provided for fourth comparison circuit 114. The set value Q3 is input to the third adder circuit 133, and Q'3 (Q3 +Q'3-Q4) is input via the third gate 143. Similarly, the fourth adder circuit 134 receives the set value R3 and R′3 (where R3+
R' 3 = RJ) is input. Similarly, the fourth
The adder circuit 134 includes the setting IJ R3 and R'3 (R3+R'3) via the fourth gate 144.
=R4) is input. This circuit is connected to the first and second circuits described above.
It operates in the same way as the comparison circuit, and as a result, the exhaust cut valve 223 is opened based on the QJ and RJ lines in Figure 3 when transitioning to the high intake air amount area, and when transitioning to the low intake air amount area. When transitioning to Q3. The valve 223 is operated to close by the R3 line.

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 the six valves described above. In other words, when transitioning to the high intake air amount region, Q6°R6
The intake cut valve opening control is performed by the lines Qs and Rs, and the intake cut valve closing control is performed by the lines Qs and Rs when transitioning to the low intake air amount region. Here, Q6 and R6 are similarly Qs +Q' 5-Q6. R, 10R'5-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.

A timer 150 is provided that starts counting up when the output of the second OR circuit 122 for operating the air cut valve changes from ON to OFF, and the count value of this timer 150 is Set value (e.g. 2
A seventh comparison circuit 117 is provided, which issues an ON signal when the value exceeds a value corresponding to seconds.
When an ON signal is output from
47 to forcibly close the intake cut valve 232, and at the same time set Q, R ()J, semi-value to Q6. R6 and also resets the timer 150.

-I'' When the seventh gate 1-147 is closed, the output of the seventh comparator circuit 17 is turned OFF, but the reference value, which is the switching line, is 06 as described above. ．． R6
Therefore, the intake cut valve operating solenoid 238 is maintained in the closed operating state. As a result, when transitioning to the low intake air m range, the exhaust cut valve solenoid 238
This prevents surging from occurring due to the intake cut valve solenoid 240 remaining in the ON state for a long time when the intake air cut valve solenoid 240 is in the OFF state.

In the above configuration, the control unit 246
In response to the outputs of the throttle sensor (acceleration detection means) and shift sensor (shift position detection means) 259, the supercharging pressure is adjusted to the set pressure when the engine 201 accelerates, and the lower the shift position, the lower the set pressure is compensated. It functions as a control means for controlling the exhaust leak valve (supercharging pressure 1 adjusting means) 230 so as to

(Effects of the Invention) As explained above, according to the exhaust gas control device for a turbocharged engine of the present invention, a plurality of superchargers including an exhaust turbo supercharger are arranged in parallel in the intake passage, At least one of the exhaust turbo superchargers is set as a secondary turbo supercharger, and a υF air cut valve is provided in the υ1 air passage dedicated to the secondary turbo supercharger, and the exhaust cut valve is installed only in the high intake air amount region of the engine. A supercharging pressure adjusting means is provided to open the secondary turbo supercharger and to adjust the supercharging pressure of the supercharger. The higher the value, the lower the set pressure is corrected, so that the basic effects of securing high boost pressure in the low intake air volume range and ensuring intake flow rate in the high intake air volume range are obtained, as well as improving engine performance. During acceleration, when the exhaust cut valve is opened, the drop in boost pressure caused by a delay in the response of the secondary turbocharger and a temporary decrease in the supercharging capacity of the primary turbocharger is constantly suppressed, regardless of the acceleration value. , torque shock can be reduced.

Here, specifically, the acceleration detection means is a means for detecting an acceleration request instructed to the engine, and in response to this, the control means receives the output of the acceleration detection means and detects an acceleration request instructed to the engine. At the same time, adjust the boost pressure to the set pressure
If the supercharging pressure adjustment means is controlled so that the higher the acceleration request instructed to the engine is, the lower the set pressure is corrected, the processing by the control means is started before the actual acceleration state is entered, and the supercharging Pressure can be adjusted quickly.

Furthermore, shift position detection means for detecting the shift position of the transmission is provided, and the control means receives the outputs of the acceleration detection means and the shift position detection means, and adjusts the supercharging pressure to the set pressure when the engine is accelerated. If the shift position is controlled by a supercharging pressure adjustment means that corrects the set pressure to a lower value as the gear position becomes lower, the set pressure will be corrected lower as the engine speed rises faster in the lower gears, thereby reducing the pressure during acceleration. Torque shock can be reduced. At this time, the lower the speed gear, the greater the amount of reduction in boost pressure, but the lower the speed gear, the less driving force is required from the engine, and there is more room in the engine output, so acceleration performance may decrease due to the drop in boost pressure. doesn't happen.

Further, the control means receives the output of the acceleration detection means, and adjusts the supercharging pressure to a set pressure when the engine accelerates, and temporarily corrects the set pressure to a lower value when the engine acceleration is large. By using a controlling means, the reduction in supercharging pressure can be reduced since the correction process is time-consuming.

The control means receives the output of the acceleration detection means, and adjusts the boost pressure to a set pressure when the engine accelerates, and constantly corrects the set pressure to a lower value when the engine acceleration is large. If the means is used as a controlling means, the torque shock reduction function during acceleration can be increased because the correction process is steady.

[Brief explanation of the drawing]

The drawings illustrate embodiments of the present invention, and FIG.
Figure 2 is a cross-sectional view of the differential pressure detection valve, Figure 3 is a map showing the operating area of the six valves, Figure 4 is an explanatory diagram explaining the operation of the six valves, and Figure 5 is the control circuit. 6 are explanatory diagrams showing temporal fluctuations in the boost pressure downstream of the blower during acceleration. 223... Exhaust cut valve 228... Exhaust leak passage 230... Exhaust leak valve (supercharging pressure adjustment means) 246... Control unit (control means) 256... Duty solenoid valve 259...
...Shift sensor (shift position detection means) 202...Exhaust passage 203...Exhaust passage 204...Primary turbo supercharger 206...Secondary turbo supercharger Figure 2 Figure Figure 5 Figure Haruma Figure 2 figure

Claims (5)

[Claims] (1) A plurality of superchargers including an exhaust turbo supercharger are arranged in parallel in the intake passage, and at least one of the exhaust turbo superchargers is designated as a secondary turbo supercharger and is dedicated to the secondary turbo supercharger. In an engine equipped with a turbo supercharger, an exhaust cut valve is installed in the exhaust passage of the engine, and the exhaust cut valve is opened only in the high intake air amount region of the engine to operate the secondary turbo supercharger. a supercharging pressure adjusting means for adjusting the boost pressure; an acceleration detecting means for detecting the acceleration of the engine; and receiving the output of the acceleration detecting means, the supercharging pressure is adjusted to a set pressure when the engine is accelerated, and the acceleration of the engine is adjusted. An exhaust gas control device for an engine equipped with a turbocharger, further comprising a control means for controlling a supercharging pressure adjusting means so that the set pressure is corrected to be lower as the set pressure increases. (2) In the exhaust gas control device for a turbocharged engine according to claim (1), the acceleration detection means is means for detecting an acceleration request directed to the engine, and the control means is an output of the acceleration detection means. means for controlling the supercharging pressure adjusting means so as to adjust the supercharging pressure to a set pressure when an acceleration request is instructed to the engine, and to correct the set pressure to be lower as the acceleration request instructed to the engine is larger. An exhaust control device for a turbocharged engine. (3) The exhaust gas control device for a turbocharged engine according to claim (1), further comprising shift position detection means for detecting a shift position of the transmission, and the control means includes outputs of the acceleration detection means and the shift position detection means. The exhaust gas of a turbocharged engine is a means for controlling a supercharging pressure adjusting means so that the supercharging pressure is adjusted to a set pressure when the engine accelerates, and the set pressure is corrected to be lower as the shift position is lower. Control device. (4) In the exhaust gas control device for a turbocharged engine according to claim (1), the control means receives the output of the acceleration detection means, adjusts the supercharging pressure to a set pressure when the engine accelerates, and controls the engine. An exhaust gas control device for a turbocharged engine, which controls a supercharging pressure adjusting means to temporarily correct the set pressure to a lower value when the acceleration of the engine is large. (5) In the exhaust gas control device for a turbocharged engine according to claim (1), the control means receives the output of the acceleration detection means, adjusts the supercharging pressure to a set pressure when the engine accelerates, and adjusts the supercharging pressure to a set pressure when the engine accelerates. An exhaust gas control device for a turbocharged engine, which is a means for controlling a supercharging pressure adjusting means so as to constantly correct the set pressure to a lower value when acceleration is large.