JPH11343875A - Overspeed rotation preventing device for on-vehicle internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an overspeed rotation of an internal combustion engine for protecting the internal combustion engine, aggravation of emission, and a melting loss of a catalyst provided in an exhaust passage. SOLUTION: This device is provided with an internal combustion engine 3, which is a drive source for running, with exhaust passages 16, 35 leading from an inside of a cylinder 7 of the internal combustion engine 3 to an outside thereof, and with a fuel feeding device 48 feeding fuel into the internal combustion engine 3. The internal combustion engine 3 is also provided with an exhaust control valve 32 which adjusts opening degree of the exhaust passages 16, 35. When an engine rotary speed N of the internal combustion engine 3 is not less than a prescribed engine speed Nv and a vehicle speed V exceeds a prescribed maximum vehicle speed Vmax, the exhaust control valve 32 is closed by a controller 63.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overspeed prevention device for an internal combustion engine, which prevents an internal combustion engine from running at an excessively high speed in a traveling drive device for a vehicle and protects the internal combustion engine. Things.

[0002]

2. Description of the Related Art In a vehicle such as a motorcycle, an internal combustion engine serving as a driving source for driving is generally used as a driving device for driving the vehicle.
An intake passage that communicates the outside of the internal combustion engine with the inside of the internal combustion engine body, an exhaust passage that communicates the inside of the cylinder of the internal combustion engine body to the outside, a fuel supply device that supplies fuel to the internal combustion engine, Is provided.

[0003] External air is sucked into the cylinder through the intake passage, and fuel is supplied into the cylinder by the fuel supply device. The combustion is performed by ignition, and power is output from the internal combustion engine, and the output power is transmitted to driving wheels for traveling, so that the vehicle can travel. On the other hand, the combustion gas generated by the combustion is discharged as exhaust gas from the cylinder through an exhaust passage.

[0004] When the internal combustion engine is driven, if the internal combustion engine continues to rotate at an excessively high speed, that is, if the internal combustion engine continues to rotate excessively, there is a possibility that a problem in service life may occur. Therefore, conventionally, when the above-described overspeed occurs, some of the ignitions repeatedly performed by the spark plug are stopped to reduce the rotation speed of the internal combustion engine, thereby preventing the overspeed. There is something that I did.

[0005]

However, as described above, when the ignition is stopped, the fuel supplied from the fuel supply device to the internal combustion engine flows into the exhaust passage in an unburned state when the ignition is stopped. This may lead to deterioration of emission (atmospheric release).

Further, when a catalyst is provided in the exhaust passage, as described above, if the supplied fuel is allowed to flow into the exhaust passage in an unburned state without being ignited,
The catalyst in the exhaust passage reacts at once, and the carrier of the catalyst may be damaged.

Therefore, a carburetor having a throttle valve is provided in the middle of the intake passage, and a sub-throttle valve is provided to adjust the opening of the intake passage downstream of the carburetor. At the time of overspeed, the sub-throttle valve is caused to close. By the closing operation of the sub-throttle valve, the supply amount of fuel by the carburetor is reduced, and the above-described deterioration of the emission and melting of the catalyst are caused. It is possible to avoid the problem.

However, in particular, in a low load region where the throttle valve opening of the carburetor is small, even if the sub-throttle valve is closed as described above, a large amount of intake air from the carburetor due to overspeed is generated. Due to the negative pressure, a large amount of fuel tends to be sucked into the internal combustion engine, that is, the fuel may become rich, and it is not easy to improve the deterioration of the emission. Further, in the case where a fuel injection valve for injecting fuel into the cylinder is used as another fuel supply device instead of the carburetor, even if the sub-throttle valve is closed, the emission is deteriorated. Further, there is a problem that the catalyst cannot be prevented from being melted.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and is intended to protect the internal combustion engine by preventing over-rotation of the internal combustion engine, and to reduce the emission and the exhaust passage. It is an object to prevent the provided catalyst from being damaged.

[0010]

Means for Solving the Problems An overspeed prevention device for a vehicle-mounted internal combustion engine according to the present invention for solving the above-mentioned problems is as follows.

As shown in FIGS. 1 to 9, the first aspect of the present invention provides an internal combustion engine 3 serving as a driving source for driving and an exhaust passage 16 for communicating the inside of a cylinder 7 of the internal combustion engine 3 to the outside. , 35, 36, and a fuel supply device 48 for supplying fuel 47 to the internal combustion engine 3;

An exhaust control valve 32 for adjusting the degree of opening of the exhaust passages 16, 35, 36 is provided so that the engine speed N of the internal combustion engine 3 becomes equal to or higher than a predetermined engine speed Nv and the vehicle speed V becomes a predetermined maximum. A control device 6 for closing the exhaust control valve 32 when the vehicle speed exceeds Vmax.
3 is provided.

According to a second aspect of the present invention, as shown in FIGS. 1 to 7, in addition to the first aspect of the present invention, the exhaust control valve 32 can close the exhaust passage 35 almost completely by closing the valve. It was done.

According to a third aspect of the present invention, as shown in FIGS. 8 and 9, in addition to the first or second aspect, the exhaust passages 16, 35, 3 opening toward the cylinder 7 are provided.
6 is provided with an exhaust timing control valve 69 that allows only a part of the exhaust opening 68 on the cylinder head 12 side to be opened and closed.

The exhaust timing control valve 69 is also used as the exhaust control valve 32.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment)

1 to 7 show a first embodiment.

In FIG. 1, a vehicle 1 such as a motorcycle or an automobile has a traveling drive unit 2, and an arrow Fr indicates the front of the vehicle 1.

The traveling drive unit 2 has an internal combustion engine 3 as a traveling drive source. The internal combustion engine 3 is a two-stroke engine.
A crankcase 6 supported by a body frame of the vehicle 1 and supporting a crankshaft 5, a cylinder 7 protruding upward from the crankcase 6, and a piston slidably fitted in the cylinder 7 in an axial direction. 8 and a connecting rod 9 for linking the crankshaft 5 and the piston 8 to each other.
The cylinder 7 includes a cylinder body 11 that constitutes a base portion thereof and is attached to the crankcase 6, and a cylinder head 12 that is attached to a protruding end of the cylinder body 11.

An internal space surrounded by the cylinder 7 and the piston 8 is defined as a combustion chamber 14. The cylinder 7 of the internal combustion engine body 4 has an intake passage 15 for communicating the outside with the internal combustion chamber 14. An exhaust passage 16 is formed to connect the combustion chamber 14 inside the cylinder 7 to the outside of the cylinder 7.

The traveling drive device 2 transfers air 18 outside the internal combustion engine 3 through the intake passage 15 to the combustion chamber 14.
Is provided with an air intake device 19 to be introduced into the device. The intake device 19 is provided with an intake pipe 20 extending from the cylinder 7.
And a reed valve 21 and a throttle valve 22 interposed between the cylinder 7 and an end of the intake pipe 20 on the cylinder 7 side.

The internal spaces of the intake pipe 20, the reed valve 21, and the throttle valve 22 are connected to an intake passage 2 communicating with each other.
The intake passage 23 communicates the outside of the internal combustion engine 3 with the combustion chamber 14 inside the cylinder 7 through the intake passage 15 of the cylinder 7. An accelerator operation unit 26 which is an accelerator grip provided on the vehicle body of the vehicle 1
The throttle valve 22 is interlocked and connected via a cable 27, and the driver operates the accelerator operation section 26 to operate the throttle valve 22 so that the throttle valve 22 can be opened and closed. It is adjustable.

The traveling drive device 2 includes an exhaust device 30 that leads the combustion gas generated in the combustion chamber 14 to the outside of the internal combustion engine 3 as exhaust gas 29. This exhaust device 30
Includes an exhaust pipe 31 extending from the cylinder 7 and an exhaust control valve 32 interposed between the cylinder 7 and an end of the exhaust pipe 31 on the cylinder 7 side. The exhaust pipe 31 includes an exhaust pipe main body 33 extending from the cylinder 7 and a silencer 34 extending from an extending end of the exhaust pipe main body 33. The exhaust pipe 31
Each internal space of the exhaust control valve 32 and the exhaust control valve 32 is an exhaust passage 35 communicating with each other. The exhaust passage 35 communicates the combustion chamber 14 with the outside of the internal combustion engine 3 through the exhaust passage 16 of the cylinder 7. .

1 to 3, the exhaust control valve 32 opens and closes a pipe-shaped valve body 38 provided between the cylinder 7 and the exhaust pipe 31 and an exhaust passage 35 inside the valve body 38. A butterfly type valve element 39 is provided which can be freely adjusted to adjust its opening degree. In addition, this valve element 3
9, the valve body 39 in the exhaust passage 35,
A communication hole 40 having a small area for connecting the downstream sides to each other is formed. The communication hole 40 allows a slight flow of the exhaust gas 29 even when the valve body 39 of the exhaust control valve 32 completely closes the exhaust passage 35.

An actuator 42, which is a servomotor for enabling the exhaust control valve 32 to open and close, is provided. A catalyst 44 is provided in the exhaust passage 35 at the upstream end of the silencer 34 of the exhaust pipe 31. The catalyst 44 is an oxidation catalyst and has a purification performance for CO and HC.

The traveling drive device 2 includes a fuel supply device 48 that can supply more fuel 47 to the internal combustion engine 3 as the operation force of the accelerator operation on the accelerator operation portion 26 increases. This fuel supply device 48
Has a fuel injection valve 49 attached to the cylinder 7 for injecting and supplying fuel 47 to the combustion chamber 14, and the fuel injection valve 49 can be opened and closed by a solenoid. Further, an ignition plug 51 whose discharge portion faces the combustion chamber 14 is attached to the cylinder 7.

The traveling drive device 2 includes a power transmission device 53 connected to the internal combustion engine 3. The power transmission device 53 includes a power transmission case 54 connected to the crankcase 6, a clutch 55 included in the power transmission case 54 and interlocked with the crankshaft 5, and a power transmission case 54. And a gear type transmission 56 which is internally provided and is interlocked with the clutch 55. A rear wheel, which is a driving wheel for traveling of the vehicle 1, is interlocked to the transmission 56 via a chain-wound transmission means.

A throttle valve opening detection sensor 59 for detecting the throttle valve opening TH of the throttle valve 22;
An engine speed detection sensor 60 for detecting an engine speed N of the internal combustion engine 3 and a vehicle speed detection sensor 61 for detecting a speed V of the vehicle 1 by detecting an output speed of the transmission 56 are provided. I have. In the above case, the throttle valve opening TH corresponds to the opening of the intake passage 23.

The throttle valve opening detecting sensor 59 is a potentiometer, and the engine rotational speed detecting sensor 60 detects the rotation of a flywheel magneto, such as a CDI pulsar coil, electromagnetically. The vehicle speed detection sensor 61 is calculated based on the engine speed N and the shift position. However, the vehicle speed detection sensor 61 may calculate a detection signal from a speedometer that detects the speed of the front wheels. The detection may be performed directly by a tube.

There is provided an engine control device 63 for electronically controlling the traveling drive device 2 to enable its driving. The control device 63 includes a controller 64, and a fuel injection circuit 65 and an ignition circuit 66 connected to the controller 64. The throttle valve opening detection sensor 59, the engine speed detection sensor 60, and the vehicle speed detection sensor 61 are connected to a controller 64 of the control device 63, and the fuel supply device 48
Of the fuel injection circuit 49 of the control device 63
The ignition plug 51 is connected to an ignition circuit 66 of the control device 63.

When the internal combustion engine 3 of the traveling drive device 2 is driven, the air 18 outside the internal combustion engine 3 is caused to flow by the intake negative pressure in the cylinder 7 to the intake passage 23 of the intake pipe 20 of the intake device 19. , The throttle valve 22, the reed valve 21, and the intake passage 15 of the cylinder 7 are sequentially sucked into the combustion chamber 14. At this time, the fuel injection valve 49 of the fuel supply device 48 controlled by the control device 63
Injects a fuel 47 having a predetermined fuel injection amount Q, whereby an air-fuel mixture of the air 18 and the fuel 47 is generated in the combustion chamber 14. Next, the spark plug 51 controlled by the control device 63 discharges at a predetermined crank angle, and the mixture is ignited and burned.

Thermal energy due to the heat generated by the combustion is converted into power by the internal combustion engine 3, and the power is output from the crankshaft 5 of the internal combustion engine 3, and the power is transmitted via the power transmission device 53. Transmitted to the rear wheels of the vehicle 1,
The traveling of the vehicle 1 is enabled.

In the above case, the throttle valve 22 is operated to open and close by operating the accelerator operation section 26, thereby increasing or decreasing the amount of the air 18 to be sucked in. If the supply amount of the fuel 47 to the internal combustion engine 3 is increased or decreased, the output can be increased or decreased. Further, the combustion gas generated by the combustion passes through the exhaust passage 16 of the cylinder 7, the exhaust control valve 32 of the exhaust device 30, and the exhaust passage 35 of the exhaust pipe 31 as exhaust 29, and It is discharged outside the internal combustion engine 3. When the exhaust gas 29 passes through the catalyst 44 in the exhaust passage 35, the exhaust gas 29 is purified by the catalyst 44.

In particular, according to FIGS.
The control of the traveling drive device 2 and the control of the exhaust 29 will be described in detail.

FIG. 4 shows a flowchart of the control unit 63, in which (P-1) to (P-13) show each step of the program.

In FIG. 4, after the start (P-1),
In (P-2), while the travel drive device 2 is being driven, the driver operates the accelerator operation section 26 to perform an accelerator operation, so that the opening of the intake passage 23, that is, the throttle valve opening TH is adjusted. In this case, the throttle valve opening T detected by the throttle valve opening detection sensor 59 is used.
H, the engine speed N detected by the engine speed detection sensor 60, and the vehicle speed detection sensor 6
Each detection signal of the vehicle speed V detected by 1 is input to the controller 64 of the control device 63. In this case, the throttle valve opening TH corresponds to the load of the internal combustion engine 3.

Next, in (P-3), the controller 6
4, the fuel injection amount Q corresponding to the throttle valve opening TH and the engine speed N is read. Next, in (P-4), the throttle valve opening TH is not equal to or greater than the predetermined throttle valve opening THv, and / or the engine speed N is equal to the predetermined engine speed Nv (for example,
If it is determined that the value is not equal to or more than 8000 RPM (NO), the control flow goes to (P-5) to open the exhaust control valve according to the throttle valve opening TH and the engine speed N according to the map of the controller 64. Degree θ is read, (P-6)
The opening of the exhaust control valve 32 is determined by the actuator 42 to be the exhaust control valve opening θ, and the exhaust control valve opening θ corresponds to the opening of the exhaust passage 35 (FIG. 5). Middle, excluding the shaded area with the two-dot chain line).

As shown in FIG. 5, the throttle valve opening TH is equal to or less than a predetermined throttle valve opening THv.
In the middle to low speed range of 50% or less, the throttle valve opening T
The exhaust control valve opening θ is controlled so as to decrease as H decreases. At a certain value, the throttle valve opening TH is controlled such that the smaller the engine speed N, the smaller the exhaust control valve opening θ.

Next, at (P-7), the fuel injection amount Q of the fuel 47 determined at (P-3) is injected by the fuel injection valve 49 and supplied into the cylinder 7. afterwards,
The procedure returns to (P-2).

In the above (P-4), the throttle valve opening TH
Is equal to or greater than a predetermined throttle valve opening THv, and the engine speed N is equal to or greater than a predetermined engine speed Nv (Y
(ES) (in FIG. 5, the shaded area indicated by the two-dot chain line), and at (P-8), the vehicle speed V becomes the predetermined maximum vehicle speed Vma.
x, it is determined whether or not the vehicle speed V is equal to or lower than the predetermined maximum vehicle speed Vmax (NO).
Returning to -2), if it is determined that the vehicle speed V exceeds the predetermined maximum vehicle speed Vmax (YES), (P-9) is executed.

In the above (P-9), V-Vmax = vehicle speed difference ΔV is calculated, and in (P-10), using the map of FIG. Δθ
Is calculated, and in (P-11), the exhaust control valve 32 is closed by the valve closing amount Δθ of the exhaust control valve.

Next, at (P-12), the decrease amount ΔQ of the injected fuel is calculated from the valve closing amount Δθ of the exhaust control valve using the map of FIG. The fuel injection amount of the fuel 47 by the fuel injection valve 49 is reduced by the fuel reduction amount ΔQ, the injection is executed at (P-7), and the process returns to (P-2).

According to the above configuration, the internal combustion engine 3 serving as a driving source for traveling, the exhaust passages 16 and 35 for communicating the inside of the cylinder 7 of the internal combustion engine 3 to the outside, and the fuel 47 In the traveling drive device 2 provided with the fuel supply device 48 for supplying the exhaust gas, the exhaust passages 16 and 35 are provided.
An exhaust control valve 32 for adjusting the opening of the engine is provided. The throttle valve opening TH becomes equal to or greater than a predetermined throttle valve opening THv, and the engine speed N of the internal combustion engine 3 becomes equal to or greater than a predetermined engine speed Nv. When the vehicle speed V exceeds a predetermined maximum vehicle speed Vmax, the control device 63 causes the exhaust control valve 32 to close.

That is, when it is determined that the internal combustion engine 3 has become overspeed, the exhaust control valve 32 is closed to reduce the opening degree of the exhaust passages 16 and 35.

Then, as described above, the exhaust passages 16,
If the opening degree of the exhaust passages 16 and 35 is reduced,
Since the discharge of the exhaust gas 29 passing through the cylinder 7 is restricted, the pressure in the cylinder 7 increases, and therefore, the intake amount of the air 18 into the cylinder 7 decreases, and the engine output is reduced. .

Therefore, overspeed of the internal combustion engine 3 is prevented,
This protects the internal combustion engine 3.

As described above, the exhaust passages 16, 3
When the opening degree of the cylinder 5 is reduced, the pressure in the cylinder 7 increases, and the temperature in the cylinder 7 also increases. Accordingly, incomplete combustion of the fuel 47 is suppressed.

Therefore, as described above, while the overspeed of the internal combustion engine 3 is prevented, the above-described suppression of incomplete combustion prevents deterioration of the emission and reduces the amount of unburned fuel. The reaction with the catalyst 44 is suppressed to a small extent, thereby preventing the carrier of the catalyst 44 from being melted and damaged.

The exhaust control valve 32 allows the exhaust passages 16 and 35 to be almost completely closed.

Therefore, when the internal combustion engine 3 is over-rotated, the exhaust control valve 32 controls the exhaust passage 1.
If the cylinders 6 and 35 are almost fully closed, the engine output of the internal combustion engine 3 can be more reliably reduced.

Therefore, the overspeed of the internal combustion engine 3 is more reliably prevented, and the protection of the internal combustion engine 3 is more reliably achieved. Even when the exhaust passages 16 and 35 are fully closed by the valve body 39 of the exhaust control valve 32, some exhaust 29 is exhausted through the communication hole 40. The internal combustion engine 3
Is prevented from suddenly stopping.

Further, in the present embodiment, the fuel 47
Is corrected in conjunction with the closing operation of the exhaust control valve 32, so that incomplete combustion is more reliably suppressed.

In a low load region where the accelerator operation amount is small, the amount of air 18 to be sucked is small and blow-through easily occurs. Therefore, the actual compression ratio does not increase and the mixture in the combustion chamber 14 at the time of ignition is not increased. Cannot be sufficiently high, and even if ignited, it is difficult to ignite, and even if ignited, flame propagation is unlikely to occur and misfiring may occur. In particular, when the engine speed N is low, flame propagation is less likely to occur and misfires occur more. Therefore, the exhaust control valve 32 is configured to be closed even in a low load region where the accelerator operation amount is small, and according to this, the blow-through amount of the intake air 18 and the fuel 47 is reduced, and A part of the burned gas having a high temperature is retained in the combustion chamber 14, and the substantial compression ratio is also increased to increase the temperature in the combustion chamber 14 at the time of ignition, thereby suppressing incomplete combustion and reducing fuel consumption. Can be improved. In addition, the lower the load and the lower the rotational speed, where incomplete combustion is likely to occur, the lower the exhaust control valve 3
2 is made smaller.

That is, the deterioration of the emission can be achieved by the closing operation of one exhaust control valve 32 even in the low load range in addition to the prevention of the overspeed.

Although not shown, the throttle valve 2
2 and the cable 27 are eliminated, and the exhaust control valve 32 is connected to the accelerator operation section 26 in an interlocked manner. The accelerator operation on the accelerator operation section 26 causes the exhaust control valve 32 to open and close. Air 1 sucked into 4
8 may be adjusted. In this case, an accelerator amount detection sensor capable of directly detecting the accelerator operation amount of the accelerator operation unit 26 is provided instead of the throttle valve opening detection sensor 59.

In the above configuration, the exhaust control valve 32 for the accelerator operation section 26 is controlled by the control device 63 to which each detection signal of the accelerator amount detection sensor, the engine speed detection sensor 60, and the vehicle speed detection sensor 61 is inputted. May be automatically and temporarily released, and the exhaust control valve 32 may be closed so as to prevent the internal combustion engine 3 from over-rotating.

The following figures show the second and third embodiments. Each of these embodiments has many points in common with the first embodiment in configuration and operation. Therefore, these common components are denoted by the same reference numerals in the drawings, and redundant description thereof will be omitted, and different points will be mainly described.

(Second Embodiment)

FIG. 8 shows a second embodiment.

According to this, the intake passage 15 is formed in the crankcase 6 of the internal combustion engine body 4 of the internal combustion engine 3, and the scavenging passage 17 connects the inside of the crankcase 6 with the combustion chamber 14 in the cylinder 7. Is formed in the cylinder 7, that is, the internal combustion engine 3 is a pre-compression type two-cycle engine. In addition, instead of the fuel injection valve 49 in the first embodiment, a carburetor 50 having a throttle valve is provided at an intermediate portion of the intake pipe 20,
Fuel 47 is supplied from the carburetor 50 to the intake passage 23. In this case, the load of the internal combustion engine 3 may be detected by a potentiometer provided in the carburetor 50. Reference numeral 22 in the drawing denotes a sub throttle valve.

A rotary exhaust timing control valve capable of opening and closing only a part of the exhaust opening 68 of the exhaust passage 16 opening toward the combustion chamber 14 in the cylinder 7 on the side of the cylinder head 12 (upper side). 69 are provided.

The actuator 42 of the exhaust timing control valve 69 is controlled by the control device 63. When the internal combustion engine 3 rotates at a low speed, the exhaust opening 6
8, a part of the exhaust opening 68 is opened at the time of high-speed rotation, and a part of the exhaust opening 68 is opened, so that the exhaust timing is advanced so that the engine performance can be improved. I have.

In the above configuration, the exhaust timing control valve 6
9 is also used as the exhaust control valve 32.

According to the above configuration, the exhaust control valve 32 for preventing the above-mentioned overspeed of the internal combustion engine 3 and protecting the internal combustion engine 3 is provided for improving the engine performance. Since the timing control valve 69 is used, the protection of the internal combustion engine 3 is achieved by this use with a simple configuration.

The control device 63 according to the second embodiment
, The control device 63 of FIG.
Are used, and the flowchart shows steps related to the fuel injection control from those in FIG. 4 (P-
3), (P-7), (P-12), and (P-13)
Is omitted. The exhaust timing control valve 6
No. 9, as in the first embodiment, prevents fresh air from flowing through at low load, and further increases the compression ratio to enhance ignition and ignitability, thereby ensuring irregular combustion. Can be prevented.

(Third Embodiment)

FIG. 9 shows a third embodiment.

According to this, another exhaust passage 36 is formed in the cylinder 7 as a bypass of the exhaust passage 35, and both exhaust passages 35, 36 are directed toward the combustion chamber 14 in the cylinder 7. Exhaust openings 68, 68 are open. Of these two exhaust openings 68, 68, a rotary exhaust timing in which the exhaust opening 68 of the other exhaust passage 36, which is only a part of the cylinder head 12 side (upper side), can be fully opened and fully opened and closed. A control valve 69 is provided, and the exhaust timing control valve 69 is also used as the exhaust control valve 32.

The other structure is the same as that of the second embodiment, and the operation is the same as that of the first embodiment.

[0071]

The effects of the present invention are as follows.

According to a first aspect of the present invention, there is provided an internal combustion engine serving as a driving source for traveling, an exhaust passage for communicating the inside of a cylinder of the internal combustion engine to the outside, and a fuel supply device for supplying fuel to the internal combustion engine. In a traveling drive device for a vehicle comprising:

An exhaust control valve for adjusting the degree of opening of the exhaust passage is provided. When the engine speed of the internal combustion engine is equal to or higher than a predetermined engine speed and the vehicle speed exceeds a predetermined maximum vehicle speed, the exhaust control valve is provided. Is provided with a control device for performing the valve closing operation, and the following effects are produced.

That is, as described above, when the engine speed of the internal combustion engine exceeds the predetermined engine speed and the vehicle speed exceeds the predetermined maximum vehicle speed, it is determined that the internal combustion engine has become overspeed. In such a case, the exhaust control valve is closed to reduce the opening degree of the exhaust passage.

As described above, when the opening degree of the exhaust passage is reduced, the discharge of the exhaust gas through the exhaust passage is restricted, so that the pressure in the cylinder is increased. The amount of air sucked into the cylinder is reduced, and the engine output is reduced.

Accordingly, the overspeed of the internal combustion engine is prevented, and the internal combustion engine is protected.

Further, even if a catalyst is provided in the exhaust passage, as described above, if the opening degree of the exhaust passage is reduced, the pressure in the cylinder increases. Since the temperature in the cylinder also increases, incomplete combustion of the fuel is suppressed.

Therefore, as described above, while the overspeed of the internal combustion engine is prevented, deterioration of the emission is prevented by suppressing the incomplete combustion described above.
Since the amount of unburned fuel is reduced, the reaction with the catalyst is suppressed to a small extent, and the carrier of the catalyst is prevented from being eroded.

According to a second aspect of the present invention, the exhaust control valve can close the exhaust passage almost completely by closing the exhaust control valve.

Therefore, when the exhaust gas control valve closes the exhaust passage almost completely when the internal combustion engine is over-rotated, the engine output of the internal combustion engine can be more reliably reduced. it can.

Accordingly, the overspeed of the internal combustion engine is more reliably prevented, and the protection of the internal combustion engine is more reliably achieved.

According to a third aspect of the present invention, there is provided a vehicle mounted internal combustion engine having an exhaust timing control valve provided with an exhaust timing control valve capable of opening and closing only a part of a cylinder head side of an exhaust opening of the exhaust passage opening into the cylinder. In the anti-rotation device,

The exhaust timing control valve is also used as the exhaust control valve. That is, the exhaust control valve for preventing the internal combustion engine from over-rotating and protecting the internal combustion engine is provided with engine performance. The exhaust timing control valve provided for the purpose of improvement is used, and by this use, protection of the internal combustion engine is achieved with a simple configuration.

[Brief description of the drawings]

FIG. 1 is an overall simplified diagram according to a first embodiment.

FIG. 2 is a front sectional view of an exhaust control valve according to the first embodiment.

FIG. 3 is a plan sectional view of an exhaust control valve according to the first embodiment;

FIG. 4 is a flowchart of a control device according to the first embodiment.

FIG. 5 is a map diagram showing a mutual relationship among an engine speed of an internal combustion engine, a valve opening of a throttle valve, and a valve opening of an exhaust control valve in the first embodiment.

FIG. 6 is a map diagram showing a relationship between a vehicle speed difference and a closing amount of an exhaust control valve in the first embodiment.

FIG. 7 is a map diagram showing a relationship between a valve closing amount of an exhaust control valve and a decrease amount of injected fuel in the first embodiment.

FIG. 8 is a diagram corresponding to a part of FIG. 1 in the second embodiment.

FIG. 9 is a diagram corresponding to a part of FIG. 1 in the third embodiment.

[Explanation of symbols]

 Reference Signs List 1 vehicle 2 traveling drive device 3 internal combustion engine 4 internal combustion engine main body 7 cylinder 11 cylinder main body 12 cylinder head 14 combustion chamber 15 intake passage 16, 35, 36 exhaust passage 18 air 19 intake device 22 throttle valve 23 intake passage 26 accelerator operating section 29 Exhaust 30 Exhaust device 31 Exhaust pipe 32 Exhaust control valve 42 Actuator 44 Catalyst 47 Fuel 48 Fuel supply device 59 Throttle valve opening detection sensor 60 Engine speed detection sensor 61 Vehicle speed detection sensor 63 Control device 68 Exhaust opening 69 Exhaust timing control valve TH Throttle valve opening THv Predetermined throttle valve opening N Engine speed Nv Predetermined engine speed V Vehicle speed Vv Predetermined vehicle speed ΔV Vehicle speed difference Vmax Predetermined maximum vehicle speed θ Exhaust control valve opening Δθ Exhaust control valve closing amount Q Fuel injection amount ΔQ Injection fuel reduction Small amount

Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02D 45/00 362 F02D 45/00 362Q

Claims (3)

[Claims] 1. A vehicle comprising: an internal combustion engine serving as a driving source for traveling; an exhaust passage for communicating the inside of a cylinder of the internal combustion engine to the outside; and a fuel supply device for supplying fuel to the internal combustion engine. In the traveling drive device, an exhaust control valve for adjusting an opening degree of the exhaust passage is provided, and when the engine speed of the internal combustion engine is equal to or higher than a predetermined engine speed and the vehicle speed exceeds a predetermined maximum vehicle speed, the exhaust gas is exhausted. An overspeed prevention device for a vehicle-mounted internal combustion engine provided with a control device that causes a control valve to perform a valve closing operation. 2. The overspeed prevention device for a vehicle-mounted internal combustion engine according to claim 1, wherein the exhaust control valve enables the exhaust passage to be substantially completely closed by a valve closing operation. 3. An overspeed prevention device for a vehicle-mounted internal combustion engine provided with an exhaust timing control valve provided to open and close only a part of a cylinder head side of an exhaust opening of the exhaust passage which opens into the cylinder. 3. The overspeed prevention device for a vehicle-mounted internal combustion engine according to claim 1, wherein the exhaust timing control valve is also used as the exhaust control valve.