JPH03182668A - Control device for engine - Google Patents

Abstract

PURPOSE:To perform silencing in a proper state by starting ignition operation by an ignition means when completion of closing operation of an on-off valve is detected during transfer of an engine from cranking state to a state in which closing operation is effected. CONSTITUTION:In a control unit 60, when it is detected that a signal Si is generated through turning ON of a starter switch 56 and cranking of an engine 1 is started, a timer is operated, based on the number of revolutions of an engine and other operating state indicated by means of signals Sn and Sx, a drive signal Kd is provided and inputted to a fuel injection valve 17. After the lapse of a given time starting from a point of time when the signal Si is provided, drive signals Ka and Kb are fed to solenoid valves 51 and 52 so that auxiliary exhaust gas passages 35 and 45 are brought into a closed state by on-off valves 24 and 25. Branch negative pressure passages 28A and 28B are brought into an opening state, and after the lapse of a given period, in which the valves 24 and 25 are brought into a complete closed state, starting from the point if time, a control signal Kc is inputted to an ignition purse feed circuit 57. This constitution transfers an engine to a complete explosion state.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention is directed to controlling the opening and closing of a plurality of branch passages provided in a muffler portion of an exhaust outlet passage that guides exhaust gas discharged from an engine to the outside. Accordingly, an exhaust system is installed that is designed to reduce exhaust noise when the engine is operating at low rotational speeds and to reduce power loss when the engine is operating at high rotational speeds. Engine control '4
■Regarding equipment.

(Prior Art) In the exhaust guide passageway that guides exhaust gas discharged from the engine mounted on a vehicle to the outside, a muffler is usually installed in the downstream part of the exhaust guide passage to reduce the noise accompanying the exhaust gas discharge. A muffler section is provided which forms a muffler section. As such a muffler section, one is known that has a complicated exhaust passage configuration in order to increase exhaust flow resistance and obtain a greater muffling effect. In an exhaust outlet passage equipped with a muffler portion that has such a complicated exhaust passage configuration and increased exhaust flow resistance, the engine is not required to have a large output. , when the engine is in a low-speed operating state, the advantage of effectively reducing low-frequency exhaust noise is obtained, but when the engine is in a high-speed operating state, where its output is required to be large, In this case, output loss due to large exhaust flow resistance becomes a problem.

Therefore, as shown in Japanese Utility Model Application Laid-Open No. 62-18318, for example, the muffler portion of the exhaust outlet passage extending from the engine is connected to a plurality of branch passages, for example, a first branch passage and a first branch passage for exhaust gas. A second branch passage with high flow resistance is formed, and the downstream part of the first branch passage is provided with an on-off valve driven by an actuator, for example, so that the engine is in a low rotational operating state. At some point, the first branch passage is closed by the on-off valve, so that exhaust gas is led out only from the second branch passage; on the other hand, when the engine is in high-speed operation, the on-off valve It is known to provide an exhaust control device in which the first branch passage is opened and the exhaust gas is led out from both the first and second branch passages. In such an exhaust control device, when the engine is in a low-speed operating state, the exhaust flow resistance in the exhaust outlet passage is substantially increased, thereby achieving a state in which low-frequency exhaust noise is effectively reduced. On the other hand, when the engine is in high speed operating conditions, the exhaust flow resistance in the exhaust outlet passage is substantially reduced, reducing engine power loss.

(Problem to be Solved by the Invention) In an engine that is provided with an exhaust control device as described above, whereby one of the plurality of branch passages in the muffler portion of the exhaust outlet passage is controlled to open and close by an on-off valve. However, when cranking is started with the branch passage controlled to open and close by the on-off valve in a closed state, there is a problem in that exhaust resistance increases and startability deteriorates.

Therefore, the actuator that opens and closes the on-off valve, when the engine is in a non-operating state where no negative pressure is generated,
In order to ensure that the branch passage, which is controlled to open and close by the on-off valve, is in the open state, it is usually of a negative pressure responsive type, and when cranking of the engine is started, the opening and closing of the branch passage is controlled by the on-off valve. The branch passage is set in an open state, and when cranking is finished and the engine reaches a complete explosion state, the branch passage controlled to open and close by the on-off valve is set in a closed state. It works as expected.

However, since negative pressure responsive actuators are said to be accompanied by a delay in operational response, the operation of an on-off valve that is driven to open and close by a negative pressure responsive actuator is affected by the delay in the operational response of the actuator. Become. Therefore, the complete explosion state after cranking in the engine does not ensure that the branch passage whose opening and closing is controlled by the on-off valve is in the closed state due to the delay in the operation response of the on-off valve due to the delay in the operation response of the actuator. As a result, there is a problem in that low-frequency exhaust noise is not properly muffled in the muffler section.

In view of the above, the present invention provides an on-off valve that controls the opening and closing of at least one of the plurality of branch passages formed by the muffler portion of the exhaust outlet passage, and that the on-off valve is configured to control the opening and closing of the branch passage when the engine is running at low speed. When the engine is in a rotating operating state, one of the branch passages is closed by the actuator to reduce low-frequency exhaust noise, and when the engine is in a high-speed operating state, one of the branch passages is closed. One of the opening/closing valves is set to be in the open state to reduce engine output loss, but the opening/closing valve has a delay in its operation due to a delay in the response of the actuator to the opening/closing valve. An engine control device that allows the engine to reach a complete explosion state after cranking under conditions where low-frequency exhaust noise is properly muted in the muffler section, even if the engine is The purpose is to provide

(Means for Solving the Problems) In order to achieve the above-mentioned object, an engine control device according to the present invention includes a muffler portion that forms a plurality of branch passages to guide exhaust gas from the engine to the outside. an on-off valve that controls opening and closing of at least one of the plurality of branch passages, a rotation speed detection means for detecting the engine rotation speed, and an engine rotation speed detected by the rotation speed detection means. When the value is below a predetermined value, a drive control means causes the on-off valve to perform a closing operation to close one of the branch passages, except when the engine is in a specific state at the time of starting;
A state detection means for detecting the state of the on-off valve and a start control means for controlling the start of the engine are provided, and the start control means moves the engine from the above-mentioned specific state to a state in which the on-off valve is closed. In this case, when the end of the closing operation of the on-off valve is detected by the state detection means, the ignition means provided in the engine is configured to start the ignition operation.

(Function) In the engine control device according to the present invention configured as described above, the on-off valve that controls opening/closing of at least one of the plurality of branch passages in the muffler portion is configured such that the on-off valve controls the opening/closing of at least one of the plurality of branch passages in the muffler section. Even if the engine speed is below the predetermined value, when the engine is in a certain state at the time of starting, for example, in a cranking state, one of the branch passages shall be left open, and after that, the engine speed is below the predetermined value. Under the condition that
A closing operation is performed to close one of the branch passages. For example, when the on-off valve performs a closing operation to close one of the branch passages after engine cranking, the state of the on-off valve is detected by the state detection means, and the closing operation of the on-off valve is completed. When this is detected, the ignition means provided in the engine starts the ignition operation,
Control is performed to shift the engine to a complete explosion state.

By doing this, when the engine transitions to a complete explosion state after cranking, one of the branch passages in the silencer section is closed by the on-off valve, and the silencer section is closed. This is a situation in which low-frequency exhaust noise is appropriately muted. Therefore, even if the operation of the on-off valve is accompanied by a response delay due to a delay in the response of the actuator that drives the on-off valve, the complete explosion state after cranking in the engine may be caused by the low This will avoid a situation in which frequency exhaust noise is not properly muffled.

(Example) FIG. 1 shows an example of an engine control device according to the present invention.
It is shown together with the rotary engine to which it is applied.

The engine 1 shown in FIG. 1 includes a housing 2 and a rotor 5 disposed within the housing 2. two intake boat parts 8 that guide the intake air passed through the housing to the working chamber 3 formed in the housing, and one exhaust boat part 9 that discharges exhaust gas discharged from the engine l into the exhaust outlet passage 20. is provided. The intake air introduction passage 10 is sequentially connected to an air cleaner 11 . An air flow meter 12, a throttle valve 13, and a surge tank 15 are provided, and an intake manifold 16 formed by the downstream portion thereof is connected to an intake boat section 8 provided in the housing 2 of the engine l. It is connected. Intake manifold 1
6 is equipped with a fuel injection valve 17 that injects fuel into one of the two intake boat sections 8 provided in the housing 2.

The exhaust outlet passage 20 has an upstream end connected to an exhaust boat part 9 provided in the housing 2, and an intermediate part located downstream of the part where the three-way catalytic converter 21 is provided is divided into two parts. A first main branch exhaust passage 22A and a second main branch exhaust passage 22B are formed by branching.

The first and second main branch exhaust passages 22A and 22
The downstream portion of B includes silencer portions 23A and 23, respectively.
B is provided.

First main branch exhaust passage 22A in the exhaust outlet passage 20
The silencer part 23A provided in the case 30 has a first chamber 32 divided by a partition wall 31 and a second chamber 33 whose volume is larger than the volume of the first chamber 32. An opening 30a and openings 30b and 30c are formed in the upstream end face and the downstream end face of the case 30, respectively. In addition, the partition wall 31
Openings 31a and 31b1 and a communication hole 31c are formed in the case 30, and the position of the opening 31a corresponds to the position of the opening 30a formed in the case 30.

A downstream portion of the first main branch exhaust passage 22A of the exhaust outlet passage 20 is inserted into the opening 30a formed in the upstream end face of the case 30 and the opening 31a formed in the partition wall 31, and In the opening 31b formed in the partition wall 31 and the opening 30b formed in the downstream end face of the case 30, a first sub-branch exhaust passage 34 forming the downstream part of the exhaust outlet passage 20 is connected to the downstream side thereof. It is inserted through the muffler portion 23A with its end protruding outward from the muffler portion 23A, and furthermore, in the opening 30c formed in the downstream end face portion of the case 30, there is a second hole that forms the downstream portion of the exhaust outlet passage 20. A sub-branch exhaust passage 35 is inserted through the muffler portion 23A with its downstream end protruding outward from the muffler portion 23A.

The first sub-branch exhaust passage 34 has an opening 31b in the partition wall 31.
and the opening 30b of the case 30, and the exhaust gas discharged from the downstream part of the first main branch exhaust passage 22A into the second chamber 33 of the muffler part 23A. The length of the path leading to the outside is relatively large. On the other hand, the second sub-branch exhaust passage 35 has a length of a passage that guides the exhaust gas discharged from the downstream part of the first main branch exhaust passage 22A into the second chamber 33 in the muffler section 23A to the outside. is made to be relatively small.

Further, the muffler portion 23B disposed in the second main branch exhaust passage 22B in the exhaust outlet passage 20 is connected to the case 4.
0, a first chamber 42 divided by a partition wall 41, and a second chamber 43 whose volume is larger than the volume of the first chamber 42.
An opening 40a and openings 40b and 40c are formed in the upstream end face and the downstream end face of the case 40, respectively. Partition wall 41
Openings 41a and 41b and a communication hole 41c are formed in the case 40, and the position of the opening 41a corresponds to the position of the opening 40a formed in the case 40.

A downstream portion of the second main branch exhaust passage 22B of the exhaust outlet passage 20 is inserted into the opening 40a formed in the upstream end face of the case 40 and the opening 41a formed in the partition wall 41, and In the opening 41b formed in the partition wall 41 and the opening 40b formed in the downstream end face of the case 40, a third sub-branch exhaust passage 44 forming the downstream part of the exhaust outlet passage 20 is provided. It is inserted through the muffler portion 23B with its end projecting outward from the muffler portion 23B.Furthermore, in the opening 40c formed in the downstream end face portion of the case 40, there is a fourth hole that forms the downstream portion of the exhaust outlet passage 20. A sub-branch exhaust passage 45 is inserted through the muffler portion 23B with its downstream end protruding outward from the muffler portion 23B.

The third sub-branch exhaust passage 44 has an opening 41b in the partition wall 41.
and the opening 40b of the case 40, and the exhaust gas discharged from the downstream part of the second main branch exhaust passage 22B into the second chamber 43 in the muffler part 23B. The length of the path leading to the outside is relatively large. On the other hand, the fourth sub-branch exhaust passage 45 carries the exhaust gas discharged from the downstream part of the second main branch exhaust passage 22B into the second chamber 43 in the muffler section 23B to the outside by a length of 40 passages. is made to be relatively small.

The second sub-branch exhaust passage 35 and the fourth sub-branch exhaust passage 45, which form the downstream portion of the exhaust outlet passage 20, are provided with on-off valves 24 and 25, respectively. , and are driven to open and close by actuators 26 and 27, respectively. The downstream ends of a first branch negative pressure passage 28A and a second branch negative pressure passage 28B, which form the downstream portion of the negative pressure supply passage 28, are connected to the actuators 26 and 27, respectively.

The upstream end of the negative pressure supply passage 28 is connected to the intake air introduction passage 1.
The upstream portion 28C
A pressure accumulator 29 is disposed to maintain the negative pressure supplied to the actuators 26 and 27 at a constant value. Furthermore, a downstream end of a bypass section 50 whose upstream end is connected to the surge tank 15 is connected to a downstream end of the pressure accumulator 29 in the upstream section 28C of the negative pressure supply passage 28 .

Further, the first and second branch negative pressure passages 28A and 28B in the negative pressure supply passage 28 are provided with a control unit 60, respectively.
The actuator 26 is provided with a solenoid valve 51 that is opened when a drive signal Ka is supplied from the control unit 60, and a solenoid valve 52 that is opened when a drive signal Kb is supplied from the control unit 60. When the solenoid valve 51 is opened, and thereby the first branch negative pressure passage 28A is opened, negative pressure is supplied from the surge tank 15,
The actuator 27 is actuated to cause the on-off valve 24 to take a closed state, and the actuator 27 causes the solenoid valve 52 to take an open state, thereby opening the second branch negative pressure passage 28B.
When the on-off valve 25 is in the open state, negative pressure is supplied from the surge tank 15 to operate the on-off valve 25 to take the closed state.

A control unit 60 that supplies drive signals Ka and Kb to the electromagnetic valves 51 and 52, respectively, receives a detection output signal Sn from a rotation speed sensor 55 for detecting the rotation speed of the engine l, a signal Si from a starter switch 56, and A detection output signal Sx indicating intake air amount, cooling water temperature, etc. is supplied. The control unit 60 selectively supplies drive signals Ka and Kb to the solenoid valves 51 and 52, respectively, based on these various signals, thereby controlling the first and second branch negative pressure passages in the negative pressure supply passage 28. 28A and 28B are opened by causing the solenoid valves 51 and 52 to open, respectively, and actuate the actuators 26 and 27.
4 and 25 to perform opening/closing operations, and
A control signal Kc is supplied to the ignition pulse supply circuit 57 connected to each spark plug 7 by the ignition coil, distributor, ignition timing adjustment unit, etc., and thereby the ignition pulse supply circuit 57 ignites each spark plug 7. Control is performed so that the pulse signal Ca is supplied, and a drive signal Kd is formed and the drive signal Kd is supplied to the combustion injection valve 17 at a predetermined timing, thereby causing the fuel injection valve 17 to The control unit 60 and the actuators 26 and 27 control the injection of fuel into the working chamber 3 of the engine 1. Therefore, the control unit 60 and the actuators 26 and 27 constitute drive control means for the on-off valves 24 and 25. It turns out.

The built-in memory of the control unit 60 stores, for example, a characteristic diagram as shown in FIG. 2 in which the vertical axis represents the opening TH of the throttle valve 13 and the horizontal axis represents the engine speed NE. A data map corresponding to is stored,
Opening/closing control of the electromagnetic valves 51 and 52 is performed by comparing the engine rotational speed corresponding to the detection output signal Sn with this data map. In the characteristic diagram shown in FIG. 2, a curve Ll represents a state in which the engine 1 operates with an intake air amount IQI and a state in which it operates at a rotation speed N1, a curve Ll represents a state in which the engine 1 operates with an intake air amount Q2, and a state in which it operates at a rotation speed N2. Song I that expresses the state of operation with
JIL2. A curve L3 represents a state in which the engine 1 operates with an intake air amount Q3 and a rotation speed N3, and a curve L3 represents a state in which the engine 1 operates with an intake air amount Q4 and a rotation speed N4. L4 is shown. Intake air amount Q1~Q4
are in the relationship Q2<Ql<Q4<Q3, and the engine rotational speeds Nl to N4 are in the relationship N2<Nl<N4<N3. Note that the maximum value of the throttle opening TH is expressed by Dm.

The control unit 60 controls the first negative pressure supply passage 28.
The opening/closing control for the second branch negative pressure passages 28A and 28B is performed when the engine 1 is in a normal operating state including an idling state.

When the opening/closing control of the first branch negative pressure passage 28A of the negative pressure supply passage 28 is performed by the control unit 60, the engine I is in an accelerating state, and the detection output signal Sn is detected as the engine rotation speed. When the engine speed changes upward, when the engine speed passes through curve Ll in the characteristic diagram shown in FIG.
supply is stopped, the solenoid valve 51 is closed, and the first branch negative pressure passage 28A is thereby changed from the open state to the closed state. In such a case, a state is taken in which negative pressure from the surge tank 15 is not supplied to the actuator 26,
The on-off valve 24 is moved from the closed state to the open state, and the second sub-branch exhaust passage 35 is opened. Most of the exhaust gas introduced into the second chamber 33 in the muffler section 23A is exhausted to the outside through the second sub-branch exhaust passage 35, and the remaining part is formed in the partition wall 31. Communication hole 3Lc
is introduced into the first chamber 32 through the opening 31b formed in the partition wall 31, and is introduced into the first sub-branch exhaust passage 34, and is then introduced into the first sub-branch exhaust passage I! It is assumed that it is discharged to the outside from s34.

Further, the engine 1 is in a deceleration state, and the detection output signal Sn
When the engine speed changes downward due to a hailstorm, the engine speed changes according to the curve L in the characteristic diagram shown in Fig. 2.
2, the drive signal Ka is supplied to the solenoid valve 51, and the solenoid valve 51 is opened, thereby changing the first branch negative pressure passage 28A from the closed state to the open state. In such a case, a state is taken in which negative pressure from the surge tank 15 is supplied to the actuator 26 via the pressure accumulator 29, and the on-off valve 24 is displaced from the open state to the closed state. The second sub-branch exhaust passage 35 is closed, and the exhaust gas is introduced from the engine 1 into the second chamber 33 in the muffler section 23A through the first main branch exhaust passage 22A in the IP air outlet illumination passage 20. , all of which are partition walls 31
from the communication hole 31c formed in the first sub-branch exhaust passage 3
4 and is discharged to the outside from the first sub-branch exhaust passage 34.

On the other hand, when the control unit 60 performs the opening/closing control of the on-off valve 25, the engine 1 is in an accelerating state, and if the detection output signal Sn indicates an increase in the engine rotational speed, the engine rotational speed increases. The song ji! in the characteristic diagram shown in FIG. When passing through L3, the solenoid valve 52
The supply of the drive signal Kb to the second branch negative pressure passage 28 is stopped, and the solenoid valve 52 is closed.
B is changed from the open state to the closed state. In such a case, a state is taken in which negative pressure from the surge tank I5 is not supplied to the actuator 27, and the on-off valve 25 is displaced from the closed state to the open state, so that the fourth sub-branch exhaust passage 4
5 is opened, and most of the exhaust gas introduced from the engine 1 into the second chamber 43 in the muffler section 23B through the second main branch exhaust passage 22B in the exhaust outlet passage 20 is The remaining part is introduced into the first chamber 42 through the communication hole 41c formed in the partition wall 41, and the remaining part is introduced into the first chamber 42 through the opening 41b formed in the partition wall 41. is introduced into the third sub-branch exhaust passage 44 through the third sub-branch exhaust passage 44.
is assumed to be discharged to the outside. Also, engine 1
is in a deceleration state and the detected output signal Sn changes downward.When the engine speed changes downward, when the engine speed passes through curve L4 in the characteristic diagram shown in FIG. is supplied, the solenoid valve 52 is opened, and the second branch negative pressure passage 28B is thereby changed from the closed state to the open state. In such a case, a state is taken in which negative pressure from the surge tank 15 is supplied to the actuator 27 via the pressure accumulator 29, and the on-off valve 25 is displaced from the open state to the closed state. The No. 4 sub-branch exhaust passage 45 is closed, and the exhaust gas introduced from the engine l through the second main branch exhaust passage 22B in the exhaust outlet passage 20 into the second chamber 43 in the muffler portion 23B is All communication holes 41 formed in the partition wall 41
c into the third sub-branch exhaust passage 44, and is discharged from the third branch exhaust passage 44 to the outside.

As mentioned above, the on-off valves 24 and 25 change the engine speed to the curves Ll and L3 shown in the characteristic diagram shown in FIG. When the number passes, the first and second branch negative pressure passages 28A and 28B in the negative pressure supply passage 28 are respectively closed and opened, and the exhaust gas introduced into the muffler section 23A is closed. Most of the gas flows through the second sub-branch exhaust passage 3 having a relatively small passage length.
5 to the outside, and most of the exhaust gas introduced into the muffler section 23B is exhausted to the outside from the fourth sub-branch exhaust passage 45 forming a relatively small passage length. The state to be taken is caused to be taken. Therefore, the exhaust gas is discharged to the outside in such a case while the exhaust gas flow resistance in the exhaust outlet passage 20 is substantially reduced, and as a result, the output loss of the engine l is effectively reduced. It will be done.

On the other hand, the on-off valves 24 and 25 each have a detection output signal Sn
When the engine speed changes downward, the first and second branch negative pressure passages 28A in the negative pressure supply passage 28 pass through curves L2 and L4 shown in the characteristic diagram shown in FIG. and 28B are respectively opened and closed, and all of the exhaust gas introduced into the muffler section 23A is transferred to the outside from the first sub-branch exhaust passage 34 forming a relatively large passage length. The condition is such that it is discharged into
Further, all of the exhaust gas introduced into the muffler portion 23B is arranged to be exhausted to the outside through the third sub-branch exhaust passage 44 forming a relatively long passage length. Therefore, the exhaust gas is discharged to the outside in such a case while the exhaust gas flow resistance in the exhaust outlet passage 20 is substantially increased, and as a result, low-frequency exhaust noise can be effectively reduced. It turns out.

The control unit 60 that operates as described above operates when the engine 1 is in a non-operating state and no negative pressure is generated in the intake introduction passage IO, so that the actuators 26 and 27 are in a non-operating state. The on-off valves 24 and 25 are
With the second and fourth sub-branch exhaust passages 35 and 45 assumed to be in the open position, the starter switch 56 is turned on and the signal Si is supplied, thereby causing the engine 1 When it is detected that cranking has started, the built-in timer starts operating, and the detection output signals Sn and SX are output as drive signals based on the rotational speed of the engine 1 and other operating conditions. Kd is generated and the drive signal Kd is supplied to the fuel injection valve 17. As a result, fuel is injected from the fuel injection valve 17 into the working chamber 3. and,
From the time when the signal Si is supplied, the negative pressure generated within the intake introduction passage 10 is activated by the actuators 26 and 27.
When a predetermined period of time, e.g. 1 second, has elapsed which shall be sufficient to activate
In order to close the second and fourth sub-branch exhaust passages 35 and 45, drive signals Ka and Kb are supplied to the solenoid valves 5I and 52 to close the first and second branch negative pressure. The passages 28A and 28B are opened, and the surge tank 15
Negative pressure from the actuators 26 and 27 is supplied to the actuators 26 and 27. Furthermore, the control unit 60 controls the solenoid valve 51
From the time when the supply of the drive signals Ka and Kb to the on-off valves 24 and 25 is started, the delay in the operation response of the on-off valves 24 and 25 due to the delay in the operation response occurring on the actuators 26 and 27 is taken into consideration. When a predetermined period of time, for example, one second, during which a reliable closed state is obtained has elapsed, a control signal Kc is supplied to the ignition pulse supply circuit 57. In the ignition pulse supply circuit 57, when the control signal Kc is supplied, the supply of the ignition pulse signal Ca to the ignition plug 7 is started, thereby starting the ignition operation in the working chamber 3 of the engine l, and the engine starts. It is forced into a state of complete explosion.

In this way, when the starter switch 56 is turned on and the engine 1 is shifted from cranking to the starting state, there is a delay in the response of the on-off valves 24 and 25 due to the delay in the response of the actuators 26 and 27. Even if this occurs, the second and fourth sub-branch exhaust passages 35 and 45
However, the complete explosion state of the engine 1 is started under the condition that the on-off valves 24 and 25 are reliably closed, respectively, thereby reducing the low-frequency exhaust noise when starting the engine 1. This will result in an effective reduction of

Under such an operation, the negative pressure generated in the intake passage 10 when the engine 1 transitions from cranking to a complete explosion state is relatively small, and therefore,
A predetermined period of time is required for the negative pressure in the pressure accumulator 29 to reach a predetermined value or higher, and there is a risk that the negative pressure may not be quickly supplied to the actuators 26 and 27 via the pressure accumulator 29. When actuators 26 and 2
7 includes a bypass section 50 provided for the pressure accumulator 29.
Negative pressure will be supplied directly via the This prevents the actuators 26 and 27 from experiencing a delay in operational response due to insufficient negative pressure in the pressure accumulator 29.

In the above example, based on the operation of a timer built into the control unit 60, the first and second branch negative pressure passages 28A and 28B are opened after a predetermined period has elapsed since the start of the engine 1. In order to open the solenoid valve 5,
Drive signals Ka and Kb are supplied to 1 and 52, and
After that, when a predetermined period of time has elapsed, a control signal Kc is supplied to the ignition pulse supply circuit 57 connected to the ignition plug 7 so that the mixture is combusted in the engine 1. Instead, the actuators 26 and 27 are each equipped with a sensor that detects the stroke amount thereof, and the control unit 60 controls the solenoid valve 51 based on the detection output signal obtained from the sensor.
supplying drive signals Ka and Kb to and 52, and
The control signal Kc may be supplied to the ignition pulse supply circuit 57.

Further, in the above example, the exhaust outlet passage 20 is
Main branch exhaust passage 22A and second main branch exhaust passage 22
B, the first and second main branch exhaust passages 2
2A and 22B are provided with muffler parts 23A and 23B, respectively, to form a two-system exhaust passage system, and a second sub-branch exhaust passage 35 and a fourth sub-branch exhaust passage extend from the muffler parts 23A and 23B, respectively. On-off valves 24 and 2 are provided in the passage 45.
However, in the engine control device according to the present invention, it is not necessary to do this, and the two exhaust passage systems are provided with different exhaust flow resistances, and the exhaust flow resistance is different. An on-off valve corresponding to the above-mentioned on-off valve 24 or on-off valve 25 may be provided only in the exhaust passage system with the larger flow resistance.

(Effects of the Invention) As is clear from the above description, the engine control device according to the present invention controls opening and closing of at least one of the plurality of branch passages formed by the muffler portion of the exhaust outlet passage. The on-off valve is provided with an on-off valve that opens one of the branch passages when the engine is in a specific state at the time of starting, for example, in a cranking state, even if the engine speed is below a predetermined value. After that, with the engine speed being below a predetermined value, a closing operation is performed to close one of the branch passages,
Furthermore, when the on-off valve performs a closing operation to close one of the branch passages after cranking the engine, when it is detected that the on-off valve has completed the closing operation, the on-off valve installed in the engine Since control is performed to cause the ignition means to start ignition and move the engine to a complete explosion state, when the engine shifts to a complete explosion state after cranking, one of the branch passages in the silencer section is closed by an on-off valve. is assumed to be in a closed state, so that low-frequency exhaust noise is properly muffled in the muffler section. Therefore, even if the operation of the on-off valve is accompanied by a response delay due to a delay in the response of the actuator that drives the on-off valve, the complete explosion state after cranking in the engine may be caused by the low This makes it possible to avoid a situation in which frequency exhaust noise is not properly muffled.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an example of an engine control device according to the present invention together with a rotary engine to which it is applied, and FIG. 2 is a characteristic diagram used to explain the operation of the example shown in FIG. 1. . In the figure, 1 is an engine, 7 is a spark plug, 20 is an exhaust outlet passage, 23A and 23B are silencer parts, 24 and 25 are on-off valves, 26 and 27 are actuators, 28 is a negative pressure supply passage, and 35 is a second 45 is a fourth sub-branch exhaust passage, 51 and 52 are electromagnetic valves, 55 is a rotation speed sensor, 56 is a starter switch, and 60 is a control unit.

Claims (1)

[Scope of Claims] An exhaust outlet passage that has a muffler portion forming a plurality of branch passages and guides exhaust gas from the engine to the outside; and controlling opening/closing of at least one of the plurality of branch passages. an on-off valve; a rotation speed detection means for detecting the rotation speed of the engine; and when the rotation speed detection means detects that the rotation speed of the engine is less than or equal to a predetermined value, the rotation speed of the engine is specified when the engine is started. drive control means for causing the on-off valve to perform a closing operation to close the one branch passage; a state detection means for detecting the state of the on-off valve; and a state detection means for detecting the state of the on-off valve; When transitioning from the state to a state in which the closing operation of the on-off valve is performed, when the state detection means detects the end of the closing operation of the on-off valve,
An engine control device comprising: a start control means for causing an ignition means provided in the engine to start an ignition operation;