JPH04292534A - Exhaust control device of internal combustion engine for vehicle - Google Patents

Abstract

PURPOSE:To make an exhaust system compact, and reduce the exhaust noise at the time of travelling at low speed, and improve drivability at the time of travelling at high speed in an exhaust control device of internal combustion engine for vehicle, which controls flow area of an exhaust passage in response to the operation condition of an engine. CONSTITUTION:In an exhaust system E, a negative pressure operation type actuator 27, which drives an exhaust control valve 16 to the direction for reducing open degree thereof in response to increase of the negative pressure, is connected to the exhaust control valve 16, which can change open degree of an exhaust passage connected to the downstream end of an exhaust manifold 14. This actuator 27 is connected to the downstream side more than a throttle valve 11 of an intake system 1 through a throttle ratio change means 28 for changing contraction percentage to a small value and a large value in response to high speed and low speed of a vehicle.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas control device for a vehicle internal combustion engine, which controls the flow area of an exhaust passage in accordance with the operating condition of the engine.

0002

[Prior Art] Conventionally, for example, Utility Model Application No. 52-38512
As disclosed in the above publication, there is one in which a plurality of exhaust passages are selected depending on the engine speed, thereby changing the flow area of the exhaust passage.

0003

[Problems to be Solved by the Invention] In internal combustion engines for vehicles, exhaust noise can be reduced by reducing the area of the exhaust passage, whereas increasing the area of the exhaust passage improves acceleration response due to the reduction in flow resistance. Good drivability can be obtained. However, while low exhaust noise is more important when the vehicle is running at low speeds, it is more important to improve acceleration response when driving at high speeds. The passage area changes in stages and does not correspond to the vehicle running speed, so when the throttle valve is suddenly opened when driving at low speeds, the exhaust passage area suddenly increases, causing exhaust noise. It is difficult to both suppress the increase and improve acceleration response during high-speed driving. Further, in the above-mentioned conventional technology, it is necessary to provide a plurality of exhaust passages in the exhaust system, which inevitably increases the size of the exhaust system structure.

The present invention has been made in view of the above circumstances, and provides an internal combustion engine for a vehicle that has a compact exhaust system, reduces exhaust noise when the vehicle is running at low speeds, and improves drivability when the vehicle is running at high speeds. The purpose of the present invention is to provide an exhaust gas control device.

[0005]

[Means for Solving the Problems] In order to achieve the above object, according to a first feature of the present invention, the opening degree of the exhaust passage leading to the downstream end of the exhaust manifold in the exhaust system connected to the engine body is continuously adjusted. An exhaust control valve is provided as a variable exhaust control valve, and a negative pressure operated actuator is connected to the exhaust control valve to drive the exhaust control valve in a direction in which the opening degree thereof becomes smaller in response to an increase in negative pressure, and the actuator is configured to: The control unit is connected to the downstream side of the throttle valve of the intake system via a throttle rate changing means that operates to change the throttle rate in response to a signal from a control unit, and the control unit adjusts the throttle rate depending on whether the vehicle speed is high or low. It is configured to give a signal for changing the aperture rate from small to large to the aperture rate changing means.

According to a second feature of the present invention, an exhaust control valve is disposed in the exhaust system connected to the engine body so as to continuously vary the opening degree of the exhaust passage leading to the downstream end of the exhaust manifold. A negative pressure operated actuator is connected to the control valve, which drives the exhaust control valve in a direction that reduces its opening in response to an increase in negative pressure, and the actuator communicates with the orifice in response to a signal from the control unit. The intake system is connected to the downstream side of the throttle valve of the intake system via a first on-off valve that switches on/off, and a second on-off valve that can switch on/off in response to a signal from the control unit. The control unit is connected to the upstream side of the throttle valve of the system, and the control unit opens the first on-off valve and closes the second on-off valve when the vehicle speed is low, and closes the second on-off valve when the vehicle speed is high. The first on-off valve is configured to apply a signal to the first on-off valve and the second on-off valve to open the second on-off valve at the same time as closing the first on-off valve.

[0007]

Embodiments Hereinafter, embodiments of the present invention will be explained with reference to the drawings.

1 to 4 show a first embodiment of the present invention. FIG. 1 is a diagram showing an intake and exhaust system of a vehicle internal combustion engine, and FIG. 2 is an enlarged view of the second part of FIG. 1. , Figure 3 is 3 in Figure 2.
4 is an enlarged sectional view of part 4 of FIG. 1.

First, in FIG. 1, an intake system I connected to an engine body 9 of a multi-cylinder internal combustion engine mounted on a vehicle, for example, a motorcycle, includes an air cleaner 10 common to each cylinder, and an air cleaner 10 individually corresponding to each cylinder. A plurality of carburetors 12 are provided, each having a throttle valve 11 and commonly connected to the air cleaner 10, and a carburetor 12 corresponding to each cylinder.
and a plurality of intake pipes 13 that connect the engine main body 9, and the exhaust system E includes an exhaust manifold 1 that is connected to the engine main body 9 and has a plurality of exhaust pipes that individually correspond to each cylinder.
4, a single collective exhaust pipe 15 to which the downstream ends of the exhaust manifolds 14 are commonly connected, a single exhaust muffler 17,
It consists of an exhaust control valve 16 interposed between a collective exhaust pipe 15 and an exhaust muffler 17.

In FIGS. 2 and 3, the exhaust control valve 16
a body 19 whose both ends are connected to a collective exhaust pipe 15 and an exhaust muffler 17 to form an exhaust passage 18; a valve shaft 20 which is rotatably supported by the body 19 across the exhaust passage 18; The body 19 includes a butterfly-shaped valve body 21 fixed to a valve shaft 20 to open and close the exhaust passage 18.
A drum 22 and a lever 23 are fixed to one end of the valve shaft 20 protruding from the valve shaft 20 . Moreover, body 19 and drum 2
Between 2 and 2, a drum 22 is inserted in the direction in which the valve body 21 is in the closed position.
That is, a coil-shaped return spring 24 for urging the valve shaft 20 is interposed. Further, a screw member 25 serving as a stopper for abutting against the lever 23 and regulating the closed position of the valve body 21 is provided on the body 19 so as to be movable back and forth.

Referring again to FIG. 1, a negative pressure actuator 27 is connected to the drum 22 of the exhaust control valve 16 via a wire 26. This negative pressure actuator 2
7 is a direction in which the valve body 21 of the exhaust control valve 16 is moved in a direction in which the opening degree of the exhaust control valve 16 becomes smaller in order to increase the pulling force of the wire 26 in accordance with an increase in the introduced negative pressure, that is, against the spring force of the return spring 24. The actuator 27 is connected downstream of the throttle valve 11 in the intake system I via a throttle rate changing means 28.

In FIG. 4, the throttle rate changing means 28 is constructed as an electromagnetic on-off valve equipped with a throttle 29, and has a passage 30 in the intake system I on the downstream side of the throttle valve 11.
A housing 34 has a port 31 connected to the actuator 27 via a passage 32 and a port 33 connected to the actuator 27 via a passage 32.
9 is provided, and a valve body 35 that can switch communication/blocking between both ports 31 and 33 is disposed so as to be operable to open and close. The housing 34 is formed with a valve chamber 36 that communicates with the port 31 , and is also provided with a valve hole 37 that coaxially communicates with the port 33 and opens into the valve chamber 36 . A valve seat 38 is provided at the periphery of the opening end. On the other hand, the valve body 35 is housed in the valve chamber 36, and a movable core 39 is integrally connected to the valve body 35.
A spring 42 is contracted between the movable core 39 and a fixed core 41 which is surrounded by a coil 40 and is disposed opposite to the movable core 39 .

According to such aperture rate changing means 28,
When the coil 40 is demagnetized, the valve body 35 is seated on the valve seat 38 by the spring 42 and closes the valve hole 37, and the ports 31 and 33, that is, the passages 30 and 31 communicate with each other via the throttle 29. Therefore, intake system I and actuator 27
When the coil 40 is excited, the movable core 39 is attracted toward the fixed core 41 against the spring force of the spring 42, and the valve body 35 separates from the valve seat 38 and closes the valve. The hole 37 is opened, and therefore the throttle ratio between the intake system I and the actuator 27 is reduced.

Switching between demagnetization and excitation of the coil 40 in the aperture rate changing means 28 is controlled by a control unit 43 consisting of a microcomputer, and the control unit 43 controls the speed of the vehicle detected by the vehicle speed detector 44. The coil 40 is demagnetized when the vehicle speed is less than a set value, for example 30 km/h, and the coil 40 is energized when the vehicle speed exceeds the set value. In other words, when the vehicle speed is low (less than the set value), the coil 40
is in a demagnetized state, and the aperture rate changing means 28 is in a state where the aperture rate between the intake system I and the actuator 27 is increased, and when the vehicle speed is higher than a set value, the coil 40 is energized and the aperture rate changing means 28 In this case, the throttle ratio between the intake system I and the actuator 27 is reduced.

Next, the operation of the first embodiment will be explained. In the exhaust system E connected to the engine body 9, there is a single exhaust passage 1 commonly communicating with the downstream end of the exhaust manifold 14.
An exhaust control valve 16 whose opening degree is continuously variable is provided, and an actuator 27 connected to the exhaust control valve 16 is configured to reduce the engine load by reducing the opening degree of the throttle valve 11. In other words, as the intake negative pressure of the intake system I increases downstream of the throttle valve 11, the exhaust control valve 16 is driven in the direction in which its opening degree increases. This makes it possible to control the area of the exhaust passage according to the engine operating state while avoiding the occurrence of

Furthermore, a throttling rate changing means 28 is interposed between the intake system I and the actuator 27 on the downstream side of the throttle valve 11, and the throttling rate changing means 28 changes the throttling rate in accordance with the vehicle speed. changes from large to small. That is, when the vehicle speed is low, the coil 40 of the aperture rate changing means 28 is demagnetized by the control unit 43, and the aperture rate between the actuator 27 and the intake system I is large. Therefore, even if the throttle valve 11 is suddenly opened when the vehicle is running at low speed and the engine is under low load, the throttle rate changing means 28 prevents the intake negative pressure from immediately acting on the actuator 27, and the exhaust control valve 16
It is possible to prevent the opening degree from immediately increasing, thereby preventing an increase in exhaust noise, and suppressing hunting of the actuator 27 due to fluctuations in intake negative pressure when the engine is under low load. Furthermore, when the vehicle speed is high, the control unit 43 sets the throttle rate of the throttle rate changing means 28 to a small value, and a change in the intake negative pressure immediately acts on the actuator 27. It is possible to improve the valve opening response and improve drivability.

FIGS. 5 and 6 show a second embodiment of the present invention, and parts corresponding to those in the first embodiment are given the same reference numerals.

In the exhaust system E, a negative pressure actuator 27 connected to the exhaust control valve 16 disposed in a single exhaust passage 18 common to each cylinder has a negative pressure actuator 27 that can be switched between communicating and blocking the orifice 45. Intake system I via 1 on-off valve 46
It is connected to the downstream side of the throttle valve 11 in the intake system I, and is connected to the upstream side of the throttle valve 11 in the intake system I, for example, the air cleaner 10, via a second on-off valve 47 that can be switched between communication and shutoff.

The first and second on-off valves 46 and 47 are electromagnetic valves that are controlled to open and close by a control unit 43', and the first on-off valve 46 is connected to the throttle valve 11 in the intake system I, as shown in FIG. A housing 54 has a port 51 connected to the actuator 27 via a passage 48 and an orifice 45 on the downstream side thereof, and a port 53 connected to the actuator 27 via a passage 52. A valve body that can switch between communicating and blocking the ports 51 and 53 is provided in the housing 54. 55 is arranged to be operable to open and close. Moreover, the housing 54 is formed with a valve chamber 56 that communicates with the port 51 , and is also provided with a valve hole 57 that coaxially communicates with the port 53 and opens into the valve chamber 56 .
A valve seat 58 is provided around the opening end to the valve chamber 56 . On the other hand, the valve body 55 is housed within the valve chamber 56,
A spring 62 is compressed between a movable core 59 integrally connected to the valve body 55 and a fixed core 61 surrounded by a coil 60 and disposed opposite to the movable core 59.

According to the first on-off valve 46, when the coil 60 is demagnetized, the valve body 55 is seated on the valve seat 58 by the spring 62 and closes the valve hole 57.
1 and 53, that is, between the passages 50 and 51, and when the coil 60 is excited, the movable core 59 is attracted toward the fixed core 61 against the spring force of the spring 62, and the valve body 5
5 moves away from the valve seat 58 to open the valve hole 57, so that the intake system I downstream of the throttle valve 11 and the actuator 27 communicate with each other via the orifice 45.

On the other hand, the second on-off valve 47 has basically the same structure as the first on-off valve 46, and is closed when demagnetized and opened when excited.

The control unit 43' controls the vehicle speed detector 4
The vehicle speed detected by 4 is the set value, for example 30 km.
/h, the first on-off valve 46 is energized to open, and the second on-off valve 47 is demagnetized and closed, and when the vehicle speed exceeds the set value, the first on-off valve is opened. 46 is demagnetized to close the valve, and the second on-off valve 47 is excited to open the valve. Therefore, when the vehicle speed is low (less than the set value), the actuator 27 communicates with the intake system I downstream of the throttle valve 11 via the orifice 45, and when the vehicle speed is high (more than the set value), the actuator 27
7 communicates with an air cleaner 10 so that atmospheric pressure is introduced into the actuator 27.

According to this second embodiment, when the vehicle speed is low, the throttle valve 1 is
Since the intake negative pressure on the downstream side of 1 is introduced into the actuator 27, the exhaust control valve 16 is opened and closed according to the engine load, and even if the throttle valve 11 is suddenly opened, the change in the intake negative pressure is not reflected in the actuator 27. It is possible to prevent an increase in exhaust noise by avoiding an immediate effect on the exhaust noise. Further, when the vehicle speed is high, atmospheric pressure acts on the actuator 27, so the exhaust control valve 16 remains open, and good drivability can be obtained.

[0024]

As described above, according to the first feature of the present invention, the exhaust control valve is arranged so that the opening degree of the exhaust passage leading to the downstream end of the exhaust manifold is continuously variable in the exhaust system connected to the engine body. The exhaust control valve is connected to a negative pressure operated actuator that drives the exhaust control valve in a direction in which its opening degree decreases in response to an increase in negative pressure, and the actuator operates in response to a signal from the control unit. The control unit is connected to the downstream side of the throttle valve of the intake system through a throttle rate changing means that operates to change the throttle rate when the vehicle speed is high or low. Since it is configured to give a signal for changing the throttling rate to the throttle rate changing means, it is possible to reduce the exhaust noise by slowing down the change in the exhaust passage area when driving at low speeds, and to quickly follow changes in the throttle valve when driving at high speeds. The exhaust passage area can be controlled to improve acceleration response and good drivability can be obtained, and the exhaust system can be made more compact and simple by providing an exhaust control valve in a single exhaust passage. Can be done.

According to a second feature of the present invention, an exhaust control valve is disposed in the exhaust system connected to the engine body, and the exhaust control valve is arranged to continuously vary the opening degree of the exhaust passage leading to the downstream end of the exhaust manifold. A negative pressure operated actuator is connected to the control valve, which drives the exhaust control valve in a direction that reduces its opening in response to an increase in negative pressure, and the actuator communicates with the orifice in response to a signal from the control unit. The intake system is connected to the downstream side of the throttle valve of the intake system via a first on-off valve that switches on/off, and a second on-off valve that can switch on/off in response to a signal from the control unit. The control unit is connected to the upstream side of the throttle valve of the system, and the control unit opens the first on-off valve and closes the second on-off valve when the vehicle speed is low, and closes the second on-off valve when the vehicle speed is high. Since the structure is configured to give a signal to both the first and second on-off valves to close the first on-off valve and open the second on-off valve, when driving at high speed, the intake negative pressure is applied to the actuator through the orifice. By applying atmospheric pressure to the actuator, it is possible to reduce exhaust noise by slowing changes in the exhaust passage area, and when driving at high speeds, by applying atmospheric pressure to the actuator, it is possible to improve acceleration response and obtain good drivability. By providing the exhaust control valve in a single exhaust passage, the exhaust system can be made more compact and simple.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an intake and exhaust system of a vehicle internal combustion engine according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of part 2 of FIG. 1;

FIG. 3 is a sectional view taken along line 3-3 in FIG. 2;

FIG. 4 is an enlarged sectional view of part 4 of FIG. 1;

FIG. 5 is a diagram showing an intake and exhaust system of a vehicle internal combustion engine according to a second embodiment of the present invention.

6 is an enlarged sectional view of the first on-off valve in FIG. 5. FIG.

[Explanation of symbols]

9 Engine body 11
Throttle valve 14
Exhaust manifold 16
Exhaust control valve 18 Exhaust passage 27
Negative pressure actuator 2
8 Aperture rate changing means 43, 43
' Controller unit

Claims (2)

[Claims] [Claim 1] Exhaust system (E) connected to the engine body (9)
An exhaust control valve (16) is provided in which the opening degree of an exhaust passage (18) communicating with the downstream end of the exhaust manifold (14) is continuously variable. A negative pressure operated actuator (27) is connected to the exhaust control valve (16) to reduce its opening in response to a signal from the control unit (43). The control unit (43) is connected to the downstream side of the throttle valve (11) of the intake system (I) via a throttle rate changing means (28) that operates to change the throttle rate. The aperture rate changing means (
28) An exhaust gas control device for a vehicle internal combustion engine, characterized in that it is configured to provide the following. [Claim 2] Exhaust system (E) connected to the engine body (9)
An exhaust control valve (16) is provided in which the opening degree of an exhaust passage (18) communicating with the downstream end of the exhaust manifold (14) is continuously variable. A negative pressure operated actuator (27) is connected to the exhaust control valve (16) to drive the exhaust control valve (16) in a direction in which its opening degree becomes smaller.
45) and a first on-off valve (46) that switches communication/cutoff in response to a signal from the control unit (43'). In addition, it is connected to the upstream side of the throttle valve (11) of the intake system (I) via a second on-off valve (47) which can be switched between communication and isolation according to a signal from the control unit (43'). , the control unit (43') opens the first on-off valve (46) and closes the second on-off valve (47) when the vehicle speed is low, and closes the second on-off valve (47) when the vehicle speed is high. The first on-off valve (46) is closed and the second on-off valve (46) is closed.
An exhaust gas control device for an internal combustion engine for a vehicle, characterized in that it is configured to give a signal for opening an on-off valve (47) to first and second on-off valves (46, 47).