JPH02298628A - Controller for engine with supercharger - Google Patents

Abstract

PURPOSE:To obtain high supercharged pressure with good start-up at the time of small quantity of intake air by arranging a plurality of superchargers including at least one exhaust turbo supercharger in parallel in an intake passage and providing an intake cut valve, a relief valve and an exhaust cut valve in an intake passage and an exhaust passage used exclusively for the exhaust turbo supercharger. CONSTITUTION:Primary and secondary turbo superchargers 4, 6 are arranged in parallel. Two exhaust passages 2, 3 in which the turbines 5, 7 of the respective superchargers 4, 6 are arranged are communicated to each other by a communicating passage 22 of small diameter at the upperstream side of the superchargers 4, 6. In the exhaust passage 3 in which the turbine 7 on the secondary side is disposed, an exhaust cut valve 23 is provided just below the position of the opening of the communicating passage 22. In a branch passage 12 in which a blower 13 on the secondary side is provided, an intake cut valve 32 is disposed on the downstream side of the blower 13, and also intake relief valve 35 is disposed in a bypass passage bypassing the lower 13 disposed in the branch passage 12. At the time of small quantity of intake air, the exhaust and inlet cut valves 23, 32 are closed and the relief valve 35 is opened to obtain high supercharged pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a control device for a supercharged engine, and more particularly, to an engine equipped with a plurality of superchargers.

(Prior art) Conventionally, as a supercharged engine, for example, Japanese Patent Application Laid-Open No. 61-1
As disclosed in Japanese Patent No. 82421, two exhaust turbo superchargers, primary and secondary, are arranged in parallel in the intake passage, and an intake cut valve is installed downstream of the blower in the intake passage dedicated to the blower of the secondary turbo supercharger. An exhaust cut valve is installed upstream of the turbine in the exhaust passage dedicated to the turbine of the secondary turbo supercharger, and when the amount of intake air is less than a predetermined amount, such as at low speeds, the exhaust cut valve is closed and the exhaust is removed to the secondary turbo supercharger. The introduction of air is stopped and only the primary turbocharger is operated to concentrate the exhaust gas to the primary turbocharger. This prevents the pressurized air downstream of the machine's blower from flowing back into the intake passage dedicated to the secondary turbocharger's blower, while also opening the exhaust cut valve when the amount of intake air is greater than a predetermined amount, such as at high speeds. This is a so-called sequential system in which exhaust gas is also introduced into the secondary turbocharger, and the intake cut valve is opened to operate both exhaust turbochargers to ensure intake flow and obtain appropriate boost pressure.
A turbo type is known.

(Problem to be Solved by the Invention) However, in the above-mentioned conventional device, the intake cut valve remains closed even though the amount of intake air becomes larger than a predetermined amount due to a malfunction of the intake cut valve, for example. If this happens, the pressure of the intake air downstream of the secondary turbocharger's blower will rise abnormally, causing surging of the blower, and the reliability of the blower will be impaired due to an abnormal rise in intake air temperature.

In order to solve this problem, conventional methods have been used, for example,
No. 11730 discloses that an intake cut valve and an exhaust cut valve are connected via a link, and the intake cut valve is opened when the exhaust cut valve is opened to operate the secondary turbo supercharger. A technique has been disclosed that prevents the harmful effects of leaving the door open.

However, since this type of structure connects the intake cut valve and the exhaust cut valve, the structure is complicated, and if the intake cut valve itself is attached to the inner wall of the intake passage in the closed state, The pressure of the intake air downstream of the secondary turbocharger blower cannot be relieved.

By the way, in the first publication, the intake passage between the floor of the secondary turbocharger and the intake cut valve,
The intake passage upstream of the blower is connected to the intake passage through an intake recirculation passage, and an intake recirculation valve is provided in the intake recirculation passage. is opened to relieve the intake pressure downstream of the blower to the upstream side of the blower to prevent blower surging.

The present invention has been made in view of these points,
The purpose of this is to prevent the adverse effects caused by leaving the intake cut valve closed by using a valve that has the function of relieving the intake pressure downstream of the blower, such as the intake recirculation valve described above.

(Means for Solving the Problem) In order to achieve the above object, the present invention forcibly opens the relief valve when the intake cut valve is closed when the intake air amount is high and the intake cut valve should be opened.

Specifically, the solution taken by the present invention is to arrange a plurality of superchargers including at least one exhaust turbo supercharger in parallel in the intake passage, and to arrange a plurality of superchargers including at least one exhaust turbo supercharger in parallel. An intake cut valve provided downstream of the supercharger in the intake passage; an exhaust cut valve provided in the exhaust passage dedicated to the exhaust turbo supercharger; and an intake cut valve provided downstream of the supercharger in the intake passage dedicated to the exhaust turbo supercharger. and a relief valve provided upstream of the intake cut valve, a control means that opens the intake cut valve and the exhaust cut valve and closes the relief valve when the intake air amount is high, and the intake cut valve is closed when the intake air amount is high. The system also includes an abnormality countermeasure means that forcibly opens the relief valve when a problem is detected.

(Function) With the above configuration, in the present invention, when the intake air m is low,
Control means 1,1! According to the control, the exhaust cut valve is closed and the introduction of exhaust gas to at least one exhaust turbo supercharger is stopped, so the other superchargers are operated and high supercharging pressure can be easily obtained. At this time, under the control of the control means, the intake cut valve closes to prevent pressurized air from other turbochargers from flowing back into the intake passage dedicated to the exhaust turbocharger, and the relief valve opens. Blower surging during run-up to the exhaust turbocharger is prevented.

On the other hand, when the amount of intake air is high, the exhaust cut valve opens and exhaust gas is introduced into the exhaust turbo supercharger under the control of the control means, and the intake cut valve opens and the relief valve closes, so that the exhaust turbo supercharger The engine also operates to ensure the amount of intake air and to obtain the appropriate boost pressure.

For example, if the intake cut valve is left closed due to a malfunction of the intake cut valve, the abnormality countermeasure means will detect that the intake cut valve is closed during a high intake air amount and force the relief valve to close. As a result, the intake air downstream of the blower of the exhaust turbo supercharger is relieved, preventing surging of the blower due to an abnormal increase in intake pressure, and preventing an abnormal increase in intake air temperature, thereby improving the reliability of the floor. will improve. In this case, the structures around the exhaust cut valve, intake cut valve, and relief valve are not complicated, and even if the intake cut valve itself is closed and is attached to the inner wall of the intake passage, it is possible to reliably prevent blower surging. Abnormal rise in intake air temperature is prevented.

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

FIG. 1 shows a 20 device equipped with a control device according to an embodiment of the present invention.
- Shows a rotary piston engine with a supercharger. In FIG. 1, 1 is an engine, and exhaust passages 2 and 3 for each cylinder are provided independently of each other. A turbine 5 of the primary turbocharger 4 is disposed in one of these two exhaust passages 2.3, and a turbine 7 of the secondary turbocharger 6 is disposed in the other. That is, in this engine 1, the exhaust passages 2 and 3 of each cylinder are independently guided to the turbines 5.7 of the primary and secondary exhaust turbo superchargers 4.6. 6, exhaust dynamic pressure is effectively applied to both turbines 5 and 7 in the region where supercharging is performed, thereby improving supercharging efficiency. two exhaust passages 2,
3 merge into one downstream of both turbines 5 and 7,
Connected to a silencer (not shown). In addition, the intake passage 9
is divided into two downstream of an air cleaner (not shown), and the blower 11 of the primary turbo supercharger 4 is in the middle of the first branch passage 10, and the secondary turbo supercharger is in the middle of the second branch passage 12. A blower 13 of the machine 6 is installed. These branch passages 10.12 are formed so as to face each other at the branch part and extend substantially straight on both sides. In addition, the two branch passages 10, 1.2 are connected to each blower 11.
They rejoin downstream of ゜13. Then, an intercooler 14 is disposed in the intake passage 9, which has become one again, and a surge tank 15 is located downstream of the intercooler 14.
Throttle valve 1 is located between 4 and surge tank 15.
6 are arranged. Further, the downstream end of the intake passage 9 branches into two independent intake passages 17 and 18 corresponding to each cylinder of the engine 1, and is connected to each intake port (not shown). A fuel injection valve 19.20 is provided in each of these independent intake passages 17.18.

On the upstream side of the intake passage 9, an air flow meter 21 is provided, which is located upstream of the branch of the first and second branch passages 10.12, and detects the amount of intake air.

The two exhaust passages 2, 3 are communicated with each other by a relatively small diameter communication passage 22 upstream of both the primary and secondary turbochargers 4.6. In the exhaust passage 3 where the secondary turbine 7 is disposed,
An exhaust cut valve 23 is provided immediately downstream of the opening position of the communication passage 22.

Further, a turbine 5.7 extends from the middle of the communication path 22.
A bypass passage 25 is formed that communicates with the downstream combined exhaust passage 24, and a wastegate valve 27 to which a diaphragm type actuator 26 is linked is disposed in the bypass passage 25.

And, the waste gate valve 27 of the bypass passage 25
A leakage passage 2 that communicates the upstream portion with the downstream side of the exhaust cut valve 23 of the exhaust passage 3 leading to the secondary turbine 7.
8 is formed, and the leakage passage 28 is provided with an exhaust leakage valve 3 linked to a diaphragm type actuator 29.
0 is set.

The exhaust cut valve 23 is a diaphragm type actuator 3
Linked to 1. On the other hand, an intake cut valve 32 is disposed downstream of the blower 13 in the branch passage 12 in which the blower 13 of the secondary turbocharger 6 is disposed. This intake cut valve 32 is constituted by a butterfly valve, and is also linked to a diaphragm type actuator 33.

In addition, a blower 13 is installed in the branch passage 12 on the secondary side.
A relief passage 34 is formed so as to bypass the intake air, and a diaphragm type intake relief valve 35 is disposed in the relief passage 34.

The pressure chamber of the actuator 29 that operates the exhaust leak valve 30 is connected via a conduit 36 to the blower 11 of the branch passage 10 in which the blower 11 of the primary turbocharger 4 is disposed.
It is connected downstream. When the pressure on the downstream side of the blower 11 exceeds a predetermined value, the actuator 29 is actuated to open the exhaust leakage valve 30, thereby allowing a small amount of exhaust gas to flow into the bypass passage 28 when the exhaust cut valve 23 is closed. and is supplied to the secondary turbine 7. Therefore, the secondary turbo supercharger 6 starts rotating before the exhaust cut valve 23 opens. During this time, as will be described later, the intake relief valve 35 is open, which increases the rotation of the secondary turbocharger 6, improves transient response when the exhaust cut valve opens, and alleviates torque shock. .

The pressure chamber of the actuator 33 that operates the intake cut valve 32 is connected to an electromagnetic solenoid type three-way valve 38 via a conduit 37.
connected to the output port of the

Further, the actuator 31 that operates the exhaust cut valve 23 is connected to an output port of another electromagnetic solenoid type three-way valve 40 through three conduits.

Further, a pressure chamber of an actuator 41 that operates the intake relief valve 35 is connected to an output port of another three-way valve 43 of an electromagnetic solenoid type through a conduit 42. As will be described later, the intake relief valve 35 keeps the relief passage 34 open until a predetermined time before the exhaust cut valve 23 and the intake cut valve 32 open. As a result, when the secondary turbocharger 6 is pre-rotated by the exhaust gas flowing through the leak passage 28, the pressure upstream of the intake cut valve 32 is prevented from rising and entering the surging region, and the blower 1
Increase the rotation of 3.

The actuator 26 for operating the wastegate valve 27 is connected by a conduit 44 to the output port of another three-way valve 45 of the electromagnetic solenoid type.

The above four electromagnetic solenoid type three-way valves 38.40°43.
45 and four fuel injection valves 19,20 are controlled by a control unit 46 configured using a microcomputer. The control unit 46 receives the output signal of the engine speed sensor, the output signal of the air flow meter 21, as well as the throttle opening, the boost pressure P1 downstream of the primary side blower 11, and the secondary side blower 13.
An intake air temperature sensor or the like that detects the temperature of downstream intake air is input, and control as described below is performed based on the input.

One input port of the electromagnetic solenoid type three-way valve 38 for controlling the intake cut valve 32 is connected to a negative pressure tank 48 via a conduit 47, and the other input port is connected to a differential pressure detection valve (described later) via a conduit 49. 50 output port door 0. Intake negative pressure downstream of the throttle valve 16 is introduced into the negative pressure tank 48 via a check valve 51 . Further, one input port of the three-way valve 40 for controlling the exhaust cut valve is open to the atmosphere, and the other input port is connected to the conduit 47 connected to the negative pressure tank 48 via the conduit 52. It is connected. On the other hand, the intake relief valve 35
One input port of the three-way control valve 43 is connected to the negative pressure tank 48, and the other input port is open to the atmosphere. In addition, a three-way valve 4 for controlling the waste gate valve 27
One of the manual boats 5 is open to the atmosphere, and the other input port is connected by a conduit 54 to the conduit 36 communicating with the downstream side of the primary blower 11.

As shown in FIG. 2, the differential pressure detection valve 50 has two diaphragms 6, a first and a second diaphragm 6, inside its casing 61.
It is divided into three chambers 64°65.66 by 2.63. In the first chamber 64 on one end side, a first
The input port lower of the casing 61 is opened, and a compression spring 68 is disposed between the inner surface of the end portion of the casing 61 and the first diaphragm 62. Further, a second input port 9 is opened in the second chamber 65 in the middle, and an output port 9 is opened in the third chamber 66 on the other end side.
However, an atmosphere release port 71 is also opened in the side wall. A valve body 72 is fixed to the first diaphragm 62 and extends through the second diaphragm 63 and toward the output port door 0 of the third chamber 66 .

The first input port lower is connected to the downstream side of the intake cut valve 32 by a conduit 73 as shown in FIG. 1, and introduces the supercharging pressure P1 downstream of the primary blower 11 into the first chamber 64. . Further, the second input port 9 is connected upstream of the intake cut valve 32 by a conduit 74, and therefore introduces the pressure P2 upstream of the intake cut valve 32 when the intake cut valve 32 is closed. There is.

The pressure P1 introduced from the two-person cupboard lower 69.
When the difference in P2 (P2-PL) exceeds a predetermined value, the valve body 7
2 opens output port door 0. This output port door 0 is connected via a conduit 49 to a three-way valve 38 for controlling the intake cut valve 32.
is connected to one of the input ports of the Therefore, when the three-way valve 38 is ON, the conduit 37 connected to the pressure chamber of the actuator 33 for operating the intake cut valve 32 is connected to the differential pressure detection valve 5.
In the state where the conduit 49 connected to the output boat 0 is connected, the pressure upstream of the intake cut valve 32, that is, the secondary side supercharging pressure P2 approaches the primary side supercharging pressure P1, and the differential pressure Pi-P2 disappears, and furthermore, the differential pressure P2-
When P1 becomes larger than a predetermined value, the actuator 3
Atmospheric air is introduced into 3, and the intake cut valve 32 is opened. Further, when the three-way valve 38 is turned OFF and the conduit 37 on the actuator 33 side is communicated with the conduit 47 connected to the negative pressure tank 48, negative pressure is supplied to the actuator 33 and the intake cut valve 32 is closed. .

On the other hand, when the three-way valve 40 for controlling the exhaust cut valve 23 is OFF, the actuator 31 for operating the exhaust cut valve 23 connects the conduit 39 connected to the pressure chamber to the negative pressure tank 4.
When the actuator 3 is connected to the conduit 52 on the 8 side,
It is closed by supplying negative pressure to 1. Also,
When the three-way valve 40 is turned on and the conduit 39 on the output side is released to the atmosphere, the exhaust cut valve 23 is opened and supercharging by the secondary turbo supercharger 6 is performed.

Intake relief valve 35 indicates that when the three-way valve 43 for controlling the intake relief valve 35 is OFF"q, the conduit 42 connected to the pressure chamber of the actuator 41 for operating the intake relief valve 35 is communicated with the negative pressure tank 48 side. The three-way valve 4 opens when negative pressure is supplied to the valve 41.
3 is ON and the conduit 42 connected to the pressure chamber of the actuator 41 is released to the atmosphere and is closed.

In addition, an actuator 26 for operating the waste gate valve 27
When the three-way valve 45 for controlling the wastegate valve 27 is ON, it communicates with the downstream side of the primary side blower 11 via the conduit 54.36, and when the three-way valve 45 is OFF, it is released to the atmosphere.

In this embodiment, hysteresis is provided in the opening and closing operations of the exhaust cut valve 23, the intake cut valve 32, and the intake relief valve 35, as will be described later. In addition, when transitioning from the high intake air amount side to the low intake air amount area, the exhaust cut valve 2
In order to prevent backflow of intake air to the secondary blower when the intake cut valve 32 is closed and the intake cut valve 32 remains open, a predetermined period of time (for example, 2 seconds) has elapsed in this region starting from the time when the exhaust cut valve 23 is closed. Afterwards, the intake cut valve 32 is forcibly closed.

FIG. 3 is a control map showing the opening/closing control of the intake cut valve 32, the exhaust cut valve 23, the intake relief valve 35, and the waste gate valve 27, together with the opening/closing control of the exhaust leak valve 30. This map is stored in the control unit 46, and the four electromagnetic solenoid type three-way valves 38, 40, 43, 45 are controlled based on this map.

When transitioning from the low intake air amount side to the high intake air amount side, the intake relief valve 35 is open in a region where the engine speed R is low or the intake air fiQ is small.
By opening the exhaust leak valve 30, the secondary turbo supercharger 6 is pre-rotated. When the engine speed reaches R2 or the intake air amount reaches Q2,
Solenoid type three-way valve 4 for intake relief valve 35° control
3 is turned ON and the intake relief valve 35 is closed, and thereafter, the pressure downstream of the secondary side blower 13 increases until the exhaust cut valve 23 is opened. When the Q4-R4 line is reached, the solenoid type three-way valve 40 for controlling the exhaust cut valve 23 is turned on and the exhaust cut valve 23 is opened, and then the Q6-R6 line is reached and the intake cut valve 32 is turned on.
The control solenoid-type three-way valve 38 is turned ON and the intake cut valve 32 is opened, so that the secondary turbo supercharger 6
supercharging begins. In other words, the engine enters the supercharging region using both the primary and secondary superchargers at the Q6-R6 line. Note that the actuator 33 that drives the intake cut valve 32 is not controlled only by the operation of the solenoid 38, but is supplied with atmospheric pressure, which is the pressure source that opens the intake cut valve 32, via the differential pressure detection valve 50. Therefore, the actual opening operation of the intake cut valve 32 is delayed with respect to the operation of the solenoid 38. Therefore, the intake cut valve 32
Turning the control solenoid 38 from OFF to ON Q6 above
．． The R6 line is set in consideration of the delay caused by the differential pressure detection valve 50, and as a result, the Q6. The R6 line is connected to Q4 when the exhaust cut valve 23 control solenoid 40 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 the high intake air amount side to the low intake air amount side, the solenoid type three-way valves 38, which control the intake cut valve 32, the exhaust cut valve 23, and the intake relief valve 35,
40.43 has hysteresis, and Q5-R5, Q3-R3, Ql-R1, respectively, as shown by broken lines in Figure 3.
It is set to switch on the line. That is,
When moving from high intake air amount side to low intake air amount side, Q3
゜When the R3 line is reached, the exhaust cut valve 23 is controlled to close, and when the intake air amount shifts to the low intake air amount side and the Q5 and R5 lines are reached, the intake cut valve 32 is controlled to close. Opening control of the intake relief valve 35 is performed with a delay. By closing the intake cut valve 32 later than the exhaust cut valve 23 in this manner, surging is prevented from occurring during transition to the low intake air amount region.

In addition, in this embodiment, the line that turns ON and OFF the solenoid type three-way valve 45 for controlling the waste gate valve 27 is the line that turns ON and OFF the solenoid 40 for controlling the exhaust cut valve 23.
The lines Q4-R4° and Q3-R3 are made to coincide with each other. In addition, in FIG. 3, the bent portions of each of the above lines are on the so-called no-load line or load-load line.

Figure 4 shows the relationship between the six valve solenoid operating states and changes in operating conditions (the left side of the horizontal axis is the low intake air amount side, the right side is the high intake air amount side) 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 23 is completely included in the hysteresis of the opening/closing operation of the intake cut valve 32. In addition, the intake cut valve 3
2 control solenoid 38 is Q6. Even if R6 is turned ON, the actual opening operation of the intake cut valve 32 is delayed due to the action of the differential pressure detection valve 50, as shown by the broken line in the figure. Therefore, this 06. R6 is the exhaust cut valve 2 as described above.
Q4 of 3-open control. The line is close to or the same line as R4. On the other hand, since the closing operation of the intake cut valve 32 does not involve the above-mentioned delay with respect to the operation of the solenoid 38, the setting line Q5. R5 is Q
It is necessary to satisfy 5<Q3°R5<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 43 is connected to the first comparison circuit 111 shown at the top of the diagram.
It is controlled by the output of a first OR circuit 121 which receives as input the output of , and the output of a second comparison circuit 112 shown below. Here, the first comparison circuit 111 compares the intake air mQ, which is the detection signal of the air flow meter 21, with the output value of the first addition circuit 131, which is a reference value. The first adder circuit 131 is connected to Q1 in FIG.
The setting value Q1 corresponding to the line is input, and this Q
The value Q' + for l (where Q+ +Q'
I-02) is input through the first gate 141, and when the first gate 141 is opened, the signal is inputted to the first comparator circuit 111 using Q+ +Q' + =02 as a reference value. Furthermore, when the first gate 141 is closed, it is outputted to the first comparator circuit 111 using Ql as a reference value. The first gate 141 is opened and closed by the output of the first OR circuit 121.

The second comparison circuit 112 compares the engine rotation speed R detected by the engine rotation speed sensor with the output value of the second addition circuit 132, which is a reference value. The second addition circuit 132 is manually inputted with a setting value R1 corresponding to the R1 line in FIG. When the second gate 142 is opened, R, 10R' l R2 is outputted to the second comparison circuit 112 as a reference value, and the second gate 142 is When 142 is closed, it outputs R1 to the second comparison circuit 112 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 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 43 (O
(N closes the intake relief valve 35). The first and second gates 141 and 142 are closed when the output signal of the first OR circuit 121 is ON, and the OR circuit signal is ON.
Opens when F. Therefore, at the time of transition from the low intake air amount region to the high intake air amount side, the output signal of the first OR circuit 121 is OFF, so each gate 141, 142
is opened and Q2+R2 is input as a reference value to the first and second comparison circuits 111 and 112. Therefore, the third
Qz in the diagram.

When the R2 line is reached, an ON signal is issued and the intake relief valve 35 is opened. Also, this ON signal causes the first
Then, the second gates 141 and 142 are closed, 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'+ and R'1 in preparation for a transition in the opposite direction.

The exhaust cut valve actuation solenoid 40 is also controlled by a similar control circuit. That is, a third comparison circuit 113 is provided for the intake air QQ, and a fourth comparison circuit 114 is provided for the engine speed R, and the outputs of these comparison circuits 113 and 114 are sent to the second OR circuit. 122 to the solenoid 40. Third comparison circuit 113
Similarly, a third addition circuit 133 is provided for the comparison circuit 114, and a fourth addition circuit 134 is provided for the fourth comparison circuit 114. The set value Q3 is input to the third adder circuit 133, and the set value Q3 is inputted to the third adder circuit 133.
'3 (however, Q3 +Q' 3-Q4) is input. Similarly, the fourth addition circuit 134 has a set value R3,
R′3 (where R,3+
R' 3 =Ra) is input. Similarly, the fourth addition circuit 134 has a set value R3 and a fourth gate 144.
R'3 (however, R3+R'3-Ra) via
is input.

This circuit operates in the same manner as the first and second comparison circuits described above, so that when the intake air amount changes to the high intake air amount side, the exhaust cut valve 2
3 is operated to open, and when there is a transition to the low intake air amount side, Q3. The valve 23 is operated to close by the R3 line. Furthermore, the wastegate valve actuation solenoid 45 is also simultaneously controlled by the control signal output to the exhaust cut valve actuation solenoid 40.

For the intake cut valve operating solenoid 38, the outputs of the fifth and sixth comparison circuits 115, 116 are combined with the third OR.
A similar control circuit is provided, feeding via circuit 123. This control circuit includes respective comparison circuits 115,
116, fifth and sixth adder circuits 135, 136
and a fifth
and sixth gates 145 and 146. The basic operation is the same as the circuit for the joint venture described above. In other words, when transitioning to the high intake air amount side, Qs.

Intake cut valve opening control is performed using the R6 line, and when the intake air amount changes to the low intake air amount side, intake cut valve closing control is performed using the Qs and Rs lines. Here, Q6 and R6
Similarly, Qs +Q' 5-Q6. R5+R' 5 m
It is set in the form of R6.

However, in the case of this intake cut valve control circuit, a seventh gate 147 is connected to the output side of the third OR circuit 123, and a control signal is sent to the solenoid 38 via this gate 147. Then, a timer 1 starts counting up from when the output of the second OR circuit 122 for operating the exhaust cut valve changes from ON to OFF.
50 is provided, and a seventh comparison circuit 117 is provided which issues an ON signal when the count value of this timer 150 exceeds a set value (for example, a value corresponding to 2 seconds). When an ON signal is output from , the seventh gate 147 is closed, the intake cut valve 32 is forcibly closed, and at the same time, the reference values of Q and H are changed to Qs and Rs, and the timer 150 is started. Configured to reset.

Once the seventh gate 147 closes, the output of the seventh comparison circuit 117 turns OFF, but since the reference value, which is the switching line, has been changed to Qa and Rs as described above, The intake cut valve operating solenoid 38 is maintained in an operating state. As a result, when transitioning to the low intake air amount region, the exhaust cut valve solenoid 3 shown in FIG.
This prevents surging from occurring due to the intake cut valve solenoid 40 remaining in the ON state for a long time when the intake valve solenoid 8 is in the OFF state.

Furthermore, an eighth gate 161 is provided between the OR circuit 122 and the exhaust cut valve operating solenoid 40, which closes upon receiving an ON signal.

Further, a ninth gate 162 is provided between the OR circuit 121 and the intake relief valve operating solenoid 43, which closes upon receiving an ON signal. Eighth comparison circuit 164
is the intake air temperature downstream of the secondary blower 13 detected by the intake air temperature sensor to the set temperature T+ (for example, 1 degree Celsius).
00 degrees). This comparison circuit 164 outputs an ON signal when the detected intake air temperature exceeds the set temperature T1. Output signal of comparison circuit 164 and OR circuit 1
The output signal of gate 22 is input to the first AND circuit 165, and the output signal of the AND circuit 165 is input to the eighth gate 1.
61 is input. Therefore, the engine Q4-
When the OR circuit 122 outputs an ON signal to open the exhaust cut valve 23 upon reaching the R4 line, for example, the intake cut valve 32 may be left closed due to a failure or the like, and the intake air temperature downstream of the secondary floor 13 may be low. When the temperature rises to the set temperature T1 or higher, the comparison circuit 164 outputs an ON signal, which causes the AND circuit 165 to output an ON signal, and in response to this, the eighth gate 161 closes. Therefore, the ON signal to the exhaust cut valve operating solenoid 40 is cut off, the exhaust cut valve 23 is closed, the secondary side floor 13 is stopped, and surging of the floor 13 due to an abnormal increase in intake pressure downstream of the blower 13 is prevented. At the same time, abnormal rise in intake air temperature is prevented and reliability of the blower 13 is improved.

Further, the ninth comparison circuit 167 compares the intake air temperature downstream of the secondary blower 13 detected by the intake temperature sensor with the set temperature 1fJ, T2 (for example, 120 degrees Celsius). This comparison circuit 167 outputs an ON signal when the detected intake air temperature reaches the set temperature 12 or higher. The output signal of the comparison circuit 167 and the output signal of the AND circuit 165 are input to a second AND circuit 168, and the output signal of the AND circuit 168 is input to the ninth gate 162.

Therefore, as described above, due to a failure of the intake cut valve 32, etc., the intake air temperature becomes equal to or higher than the set temperature T1, and the gate 1
Even if the exhaust cut valve 23 tries to close by the closing function of the exhaust cut valve 61, for example, when the exhaust cut valve 23 does not close due to a failure of the exhaust cut valve 23 itself, the secondary turbo supercharger 6 continues to operate and the secondary side When the intake air temperature downstream of the blower 13 rises to the set temperature 12 or higher, the comparison circuit 167 outputs an ON signal, which causes the AND circuit 168 to output an ON signal, and in response, the ninth gate 162 closes. Therefore, the ON signal to the intake relief valve actuating solenoid 43 is cut off, the intake relief valve 35 is forcibly opened, and the intake air downstream of the blower 13 is relieved, causing the floor 13 to be damaged due to an abnormal increase in intake pressure downstream of the blower 13. Surging is reliably prevented, and an abnormal rise in intake air temperature is reliably prevented, thereby improving the reliability of the blower 13.

In the above control circuit, the circuit starting from the signal input of the air flow meter and the engine speed sensor to the output of the three OR circuits 121 to 123 controls the intake cut valve 32 and the exhaust cut valve 23 when the amount of intake air is high.
The control means 170 opens the relief valve 35 and closes the relief valve 35.

Further, a circuit downstream of the two OR circuits 121 and 122 constitutes an abnormality countermeasure means 171 that forcibly opens the relief valve 35 when it is detected that the intake cut valve 32 is closed during a high intake air amount. ing.

FIG. 6 is a time chart showing the special product obtained by the control by the timer 150. In this diagram,
The solid line indicates the operating state in which the line goes from Qz (R3) to Qs (Rs) in a short time, and the broken line indicates the operating state where Q9 (R3)
) to Qs (Rs). In this way, the timer 150 counts up at the same time as the exhaust cut valve 23 closes, and Q5(
R5) If the arrival to the line is slow, the intake cut valve 32 is closed when the count value reaches a value equivalent to 2 seconds, for example.
is closed. Further, simultaneously with the closing operation of the intake cut valve 32, the timer 150 is initialized.

Therefore, in the above embodiment, when the engine is on the lower intake air amount side than the line Q6-R6, the introduction of exhaust gas to the secondary turbocharger 6 is stopped.
Only the primary turbo supercharger 4 operates, and high supercharging pressure can be easily obtained. On the other hand, the engine is on line Q above.
When the intake air amount is on the higher side than 6-R6, both the primary turbo supercharger 4 and the secondary turbo supercharger 6 operate to obtain an appropriate supercharging pressure while ensuring the intake flow rate.

For example, if the intake cut valve 32 is left closed due to a malfunction of the intake cut valve 32, the abnormality countermeasure means 171 detects that the intake cut valve 32 is closed during a high intake air amount. Since the relief valve 35 is forcibly opened, the intake air downstream of the blower of the secondary turbocharger 6 is relieved, preventing surging of the blower 13 due to an abnormal increase in intake pressure, and also preventing an abnormal increase in intake air temperature. This improves the reliability of the blower 13.

Moreover, the structures around the exhaust cut valve 23, the intake cut valve 32, and the relief valve 35 are not complicated, and the intake cut valve 3
Even if the blower 2 itself is stuck to the inner wall of the intake passage 2 in a closed state, surging of the blower 13 and abnormal rise in intake air temperature can be reliably prevented.

Note that the supercharger that is switched into operation or non-operation (the secondary turbocharger 6 in the above embodiment) is an exhaust turbosupercharger, but the other superchargers are mechanical superchargers. Also good.

(Effects of the Invention) As explained above, according to the supercharged engine control device of the present invention, a plurality of superchargers including at least one exhaust turbo supercharger are arranged in parallel in the intake passage. Furthermore, an intake cut valve provided downstream of the supercharger in the intake passage dedicated to the exhaust turbo supercharger, an exhaust cut valve provided in the exhaust passage dedicated to the exhaust turbo supercharger, and an exhaust cut valve provided in the exhaust passage dedicated to the exhaust turbo supercharger; A relief valve is provided downstream of the turbocharger and upstream of the intake cut valve in the intake passage dedicated to the feeder, and when the amount of intake air is high, the intake cut valve and the exhaust cut valve are opened and the relief valve is closed. The relief valve is forcibly opened when it detects that the intake cut valve is closed when the intake air amount is low, so high boost pressure can be easily obtained at low intake air amounts, and the intake air is reduced when the intake air amount is high. While achieving the basic effect of obtaining appropriate boost pressure while securing the amount of boost, if the intake cut valve is left closed due to a malfunction of the intake cut valve, for example, the exhaust turbo supercharger blower downstream By relieving intake air, it is possible to easily and reliably prevent surging of a blower due to an abnormal increase in intake pressure, and also to improve the reliability of the blower by preventing an abnormal increase in intake air temperature.

[Brief explanation of drawings]

Fig. 1 is an overall system diagram of an embodiment of the present invention, Fig. 2 is a sectional view of a differential pressure detection valve in the embodiment, Fig. 3 is a control characteristic diagram of the embodiment, and Fig. 4 is a diagram of the differential pressure detection valve in the embodiment. FIG. 5 is a control circuit of the same embodiment, and FIG. 6 is a time chart explaining the operation of the same embodiment. 1... Engine 4... Primary turbo supercharger 6... Secondary turbo supercharger 9... Intake passage 23... Exhaust cut valve 32... Intake cut valve 35... Relief valve 170 ... Control means 171 ... Abnormality countermeasure means Fig. 2 Fig. 4 Fig. 6

Claims (1)

[Claims] (1) A plurality of superchargers including at least one exhaust turbo supercharger are arranged in parallel in the intake passage, and an intake passage provided downstream of the supercharger in the intake passage dedicated to the exhaust turbo supercharger is provided. a cut valve, an exhaust cut valve provided in an exhaust passage dedicated to the exhaust turbo supercharger, and a relief valve provided downstream of the supercharger and upstream of the intake cut valve in the intake passage dedicated to the exhaust turbo supercharger. and a control means that opens the intake cut valve and the exhaust cut valve and closes the relief valve when the intake air amount is high, and forcibly closes the relief valve when it is detected that the intake cut valve is closed when the intake air amount is high. A control device for a supercharged engine, characterized in that it is equipped with an abnormality countermeasure means that opens.