JP4995924B2 - EGR device and valve operation switching device - Google Patents

Description

The present invention relates to the EGR device and the valve operation switching retrofit location is attached to an internal combustion engine.

  Conventionally, an internal combustion engine provided with an exhaust gas recirculation (EGR) device for returning a part of exhaust gas to a combustion chamber is known. For example, since it is not necessary to attach a supercharging pump or the like to Patent Document 1, it is possible to increase the pressure and temperature in the combustion chamber while simplifying the configuration, thereby improving the EGR effect. An internal combustion engine is disclosed.

  In the internal combustion engine described in Patent Document 1, exhaust gas exhausted through an exhaust port is subjected to animal pressure in a gas storage chamber, and the exhaust gas is returned to the combustion chamber during a compression process or the like. That is, in the compression process or the like, the EGR valve disposed in the EGR port is opened. As a result, the exhaust gas in the gas storage chamber is introduced into the combustion chamber as the gas storage chamber communicates with the combustion chamber. The exhaust gas introduced into the combustion chamber is burned together with a mixed gas of air and fuel.

  As described above, the internal combustion engine that reburns the exhaust gas has an advantage that the amount of NOx contained in the exhaust gas is small as compared with the internal combustion engine that does not include the EGR device.

  By the way, it is preferable that the internal combustion engine as described above has a configuration in which the combustion speed does not become slow even if the exhaust gas is returned to the combustion chamber when the load on the internal combustion engine is small (for example, when idling). Moreover, even if air is introduced into the combustion chamber in the maximum amount, a configuration that can suppress the occurrence of knocking is desired.

  From this point of view, the present applicant has proposed an EGR device capable of selecting whether or not to circulate the exhaust gas in accordance with the load state of the internal combustion engine in Patent Document 2.

  Furthermore, in an internal combustion engine that does not include an EGR device, it is preferable that the intake gas amount can be changed according to the load state of the internal combustion engine.

JP 2000-282867 A Japanese Patent Application No. 2007-256790

  A general object of the present invention is to provide an EGR device that does not require electric power when maintaining a state in which exhaust gas is circulated and when maintaining a state in which exhaust gas is not circulated. It is to provide.

The main purpose is to change the intake gas amount according to the load condition of the internal combustion engine obtained. Moreover, the pre-change state, the valve operation switching device power for maintaining each state after the change is not required in the present invention Is to provide.

  Another object of the present invention is to change the intake gas amount in accordance with the load condition of the internal combustion engine, and to eliminate the need for electric power for maintaining the state before and after the change. Is to provide.

According to an embodiment of the present invention, an exhaust port for exhausting the intake valve disposed in an intake port for introducing air into the combustion chamber (22) (24), the exhaust gas burned in the combustion chamber (22) An EGR device (10) attached to an internal combustion engine comprising an exhaust valve (26) disposed in
An EGR valve (35) disposed in an EGR port for returning the exhaust gas to the combustion chamber (22) ;
Switching means for switching the EGR valve (35) to an operation state or an operation stop state;
Operating means for operating the switching means;
Have
The switching means includes an operating state maintaining means for maintaining the operating state until the operating state is stopped by the switching means when the operating state is set under the action of the operating means, and an operating stop state under the action of the operating means. And an operation stop state maintaining means for maintaining an operation stop state until the operation state is set by the switching means .
The actuating means is energized only when the EGR valve (35) is switched from the operation state to the operation stop state, or when the EGR valve (35) is switched from the operation stop state to the operation state, and the EGR valve (35) is operated or stopped. the while maintaining the state EGR device that will be de-energized (10) is provided.

  That is, according to the present invention, either the operation state (openable / closable state) or the operation stop state (rest state) of the EGR valve is selected according to the load state of the internal combustion engine, and the state is maintained. When in the operating state, exhaust gas is introduced into the combustion chamber when the EGR valve is opened and used for recombustion. On the other hand, when the operation is stopped, the exhaust gas is not introduced into the combustion chamber. Absent. Therefore, for example, if the EGR valve is deactivated when the load on the internal combustion engine is small or large, the exhaust gas is not introduced into the combustion chamber at this time, so that the combustion speed is prevented from slowing down. Can do. Furthermore, it can be expected that the occurrence of knocking can be suppressed.

Moreover, since the EGR valve can be switched from the operation state to the operation stop state or from the operation stop state to the operation state only by providing the operation means and the switching means, the configuration is expected to be relatively simple. it can. For this reason, it can also suppress that a cost rises.

  In addition, the energization of the operating means only needs to be performed when switching from one state to the other, and it is not particularly necessary to energize to maintain the operating state or the operation stopped state. Therefore, power consumption can be reduced.

  Furthermore, since the high-temperature burned gas is returned to the combustion chamber, the temperature of the combustion chamber when performing the compression process is increased. As a result, combustion of the air-fuel mixture is promoted. As a result, the ignition delay is reduced and the isosolubility is improved. In addition, heat loss due to low-temperature combustion is reduced, and NOx emissions are reduced.

  In addition, since there is no surplus oxygen in the burnt gas, the post-treatment of NOx is easier than in a stratified charge engine or lean combustion.

  In such a configuration, it is preferable that the operation state maintaining unit and the operation stop state maintaining unit are formed of the same member. In this case, it can be expected that the number of parts can be reduced.

Incidentally, the actuating means follow a solenoid (44) energized, de-energization described above is performed, and the displacement cam displacement (54) under the action of said solenoid (44), the displacement of the displacement cam (54) to be constructed out a displacement shaft which is displaced (60), whereas, the switching means includes a fixed cam (56), one of the displacement cam end (54) or the fixed cam (56) abutting against the pressing cam on one of the tip (58) may be configured out with the pressure cam (58) displacement member you displaced to follow the displacement shaft (60) by (90).

In this case, the EGR cam (36 ) for opening and closing the EGR valve (35) is provided with a first engagement portion (38) , the displacement member (90) is provided with a second engagement portion (94) , and the first engagement portion (94) is provided. The two engaging portions (94) may be engaged with or disengaged from the first engaging portion (38) following the displacement of the displacement shaft (60) . That is, when the one end of the pressing cam (58) comes into contact with the tip of the fixed cam (56) , the second engaging portion (94) is detached from the first engaging portion (38). While the EGR valve (35) is in the operation stop state, the first engagement portion (38 ) when one end portion of the pressing cam (58) comes into contact with the distal end portion of the displacement cam (54) which is retracted most. ) And the second engagement portion (94) to engage the EGR valve (35) .

  Here, if the displacement shaft and the fixed cam are inserted into a camshaft that opens and closes the intake valve and the exhaust valve, the switching means and the operating means can be made compact.

  Furthermore, it is preferable to provide a biasing means for biasing the rod of the solenoid so as to return it to its original position. This is because it is possible to avoid the generation of noise and to improve the wear resistance of the arm.

According to another embodiment of the present invention, a plurality of intake valves disposed in the intake port for introducing air into the combustion chamber (22) (24), the exhaust gas burned in the combustion chamber (22) A valve operation switching device (100) attached to an internal combustion engine comprising an exhaust valve (26) disposed in an exhaust port for exhausting the exhaust gas;
The intake valve (24) includes a normally- operated intake valve (122) that is always in an operating state, and a variable intake valve ( 124) that is set to either an operating state or an operation stopped state.
And switching means for switching the variable intake valve ( 124) to an operating state or an operating stop state;
Operating means for operating the switching means;
Have
The switching means includes an operating state maintaining means for maintaining the operating state until the operating state is stopped by the switching means when the operating state is set under the action of the operating means, and an operating stop state under the action of the operating means. And an operation stop state maintaining means for maintaining an operation stop state until the operation state is set by the switching means .
The actuating means is energized only when the variable intake valve (124) is switched from the operation state to the operation stop state, or when the variable intake valve (124) is switched from the operation stop state to the operation state. while maintaining the operation stop state valve operation switching device that will be de-energized (100) is provided. Here, the switching means and the operating means are configured in the same manner as described above.

According to the present invention, it is selected whether the variable intake valve is in an operation state (openable / closable state) or an operation stop state (rest state) according to the load state of the internal combustion engine, and the state is maintained. . In the operating state, intake gas is introduced into the combustion chamber when the variable intake valve is opened in synchronization with the normally operating intake valve. On the other hand, when the operation is stopped, the intake gas is introduced into the combustion chamber only through the normally- operated intake valve. Therefore, the amount of intake gas can be changed by setting the variable intake valve to either the operating state or the operation stopped state.

In addition, since the variable intake valve can be switched from the operation state to the operation stop state or from the operation stop state to the operation state only by providing the operation means and the switching means, the configuration becomes relatively simple. I can expect. For this reason, it can also suppress that a cost rises.

  Further, similarly to the above-described EGR device, the energization to the operating means may be performed only when switching from one of the variable intake valve operation state or the operation stop state to the other state. There is no particular need to energize to maintain the stopped state. Therefore, power consumption can be reduced.

According to yet another embodiment of the present invention, the exhaust and intake valves disposed in the intake port for introducing air into the combustion chamber (22) (24), the exhaust gas burned in the combustion chamber (22) A cam switching device (200) attached to an internal combustion engine, comprising an exhaust valve (26) disposed in an exhaust port.
A first cam (214) for opening and closing the intake valve (24) ;
Opening and closing the intake valve (24) , and a second cam (216) having a cam profile different from that of the first cam (214) ;
Switching means for switching a cam for opening and closing the intake valve (24) to either the first cam (214) or the second cam (216) ;
Operating means for operating the switching means;
Have
Said switching means, said second cam by said switching means when energized by and said second cam is a biased state (216) according to pre-Symbol first cam (214) under the action of said actuating means is paused biasing state maintaining means for maintaining the biasing state by the first cam (214) to urge by and said first cam is a biased state (214) is paused by (216), of said actuating means When the urging state by the second cam (216) is activated and the urging by the first cam (214) is stopped, the urging state by the first cam (214) is performed by the switching means. There is provided a cam switching device (200) comprising a biasing pause state maintaining means for maintaining a biasing state by the second cam (216) until the biasing by the second cam (216) is paused.

  According to the present invention, either the first cam or the second cam is selected as the cam for opening and closing the intake valve. Since the first cam and the second cam have different cam profiles, the lift amount of the intake valve differs between when the first cam is selected and when the second cam is selected. . Along with this, the amount of intake gas taken in from the intake valve is changed. That is, the amount of intake gas can be changed by switching from the first cam to the second cam or vice versa according to the load condition of the internal combustion engine.

Further, in the present invention, since the operation means and the switching means are provided, it is possible to switch from the state in which the intake valve is opened and closed by the first cam to the state in which the intake valve is opened and closed by the second cam, or in the opposite direction. In addition, either the state in which the intake valve is opened / closed by the first cam or the state in which the intake valve is opened / closed by the second cam is maintained. Therefore, the configuration is expected to be relatively simple, and therefore, it is possible to suppress an increase in cost.

In addition, similar to the EGR device and the valve operation switching device described above, the energization of the operating means may be performed only when the remaining cam is switched from either the first cam or the second cam. It is not particularly necessary to energize to maintain the state or the operation stop state. Therefore, power consumption can be reduced.

  The first cam and the second cam can be formed adjacent to each other in the same member, for example. In this case, the number of parts is reduced.

It is a principal part schematic longitudinal cross-sectional view of the internal combustion engine with which the EGR apparatus which concerns on 1st Embodiment was attached. 2A to 2E are schematic 360 ° development diagrams showing the relationship between the displacement cam, the fixed cam, and the pressing cam. In the internal combustion engine of FIG. 1, it is a principal part schematic longitudinal cross-sectional view which shows the state which energized the solenoid and the rod retracted | retreated. FIG. 4 is a schematic vertical sectional view of a principal part showing a state where energization of the solenoid is stopped and the rod is advanced, following FIG. 3. It is a principal part schematic longitudinal cross-sectional view of the internal combustion engine with which the valve operation switching apparatus which concerns on 2nd Embodiment was attached. It is a principal part schematic longitudinal cross-sectional view of the internal combustion engine with which the cam switching apparatus which concerns on 3rd Embodiment was attached. FIG. 7 is a schematic vertical sectional view of an essential part showing a state in which a second cam constituting the intake valve cam in the cam switching device of FIG. 6 acts on the intake valve.

Hereinafter, preferred embodiments of the EGR device, the valve operation switching device, and the cam switching device according to the present invention will be described in detail in relation to an internal combustion engine to which the EGR device, the valve operation switching device, and the cam switching device are attached. To do.

  First, an EGR device will be described as a first embodiment.

  FIG. 1 is a schematic vertical sectional view of a main part of an internal combustion engine 12 to which an EGR device 10 according to the first embodiment is attached. The internal combustion engine 12 is mounted on a vehicle such as a motorcycle, for example, and runs the vehicle by burning a mixture of air and fuel.

  First, the internal combustion engine 12 will be described. The internal combustion engine 12 includes a block main body 16 provided with a cylinder 14, a cylinder head 18 connected to the upper side of the block main body 16, and a head cover 20 that covers and protects the upper portion of the cylinder head 18.

  A piston is inserted into the cylinder 14, and this piston is connected to the crankshaft via a connecting rod. A combustion chamber 22 is formed by the upper end surface of the piston and the space covered by the cylinder head 18.

  An intake port for introducing air into the combustion chamber 22 and an exhaust port for exhausting the exhaust gas burned in the combustion chamber 22 are formed inside the cylinder head 18. An intake valve 24 is disposed at the intake port, while an exhaust valve 26 is disposed at the exhaust port.

  The intake valve 24 and the exhaust valve 26 open and close under the action of the camshaft 30 via a rocker arm. In other words, the camshaft 30 is provided with cams 32 and 34, and when the crests of the cams 32 and 34 reach predetermined positions following the rotation of the camshaft 30, the rocker arm By pressing the one end, the rocker arm rotates about its substantially middle abdomen. As a result, as either of the pressing members provided at the other end of the rocker arm presses the intake valve 24 or the exhaust valve 26, the intake valve 24 or the exhaust valve 26 moves toward the combustion chamber 22 side. Displace.

  Note that the intake valve 24 and the exhaust valve 26 return to their original positions under the elastic action of valve springs arranged around each of them.

Further, an EGR port is formed in the internal combustion engine 12, and a gas storage chamber for storing exhaust gas communicates with the EGR port. Further, the EGR valve 35 is seated or separated from the EGR port.

  That is, the cam shaft 30 is provided with an EGR cam 36 in addition to the cams 32 and 34. Accordingly, when the camshaft 30 rotates, one end portion of the rocker arm is pressed when the peak portion of the EGR cam 36 reaches a predetermined position. As a result, the rocker arm pivots around its substantially middle part, and finally, a pressing member provided at the other end of the rocker arm presses the EGR valve 35. As a result, the EGR valve 35 is displaced toward the combustion chamber 22 and exhaust gas is introduced into the combustion chamber 22.

  Similar to the intake valve 24 and the exhaust valve 26, a valve spring is also provided around the EGR valve 35. The EGR valve 35 returns to its original position under the elastic action of this valve spring.

  The above-described configurations of the intake valve 24, the exhaust valve 26, and the EGR valve 35 are well known, and therefore their illustration and detailed description are omitted. The EGR cam 36 is formed with a first tooth portion 38 as a first engaging portion.

  A cam sprocket 40 is connected to one end of the camshaft 30. The camshaft 30 rotates as the cam chain 42 wound around the cam sprocket 40 is driven.

  Further, a solenoid 44 is positioned and fixed on the head cover 20. The rod 46 of the solenoid 44 is connected to one end of an arm 50 that is rotatably supported by a stop shaft 48. On the other hand, the other end of the arm 50 moves forward and backward so as to be pressed against or separated from one end of the camshaft 30.

  The camshaft 30 is formed with an insertion hole 52 along its longitudinal direction. A distal end portion of the displacement cam 54 is inserted into the insertion hole 52, and a fixed cam 56, a pressing cam 58, a displacement shaft 60 and a coil spring 62 are inserted.

  A spring receiving washer 64 is externally fitted to one end of the displacement cam 54 protruding from the insertion hole 52. A return spring 66 is interposed between the spring receiving washer 64 and the camshaft 30.

  In the camshaft 30, an elongated hole 68 is formed near the opening of the insertion hole 52 in a direction substantially perpendicular to the longitudinal direction. On the other hand, the displacement cam 54 is formed with a pin hole 70 extending in a direction substantially perpendicular to the longitudinal direction thereof, and the pin hole 70 is positioned to extend to the vicinity of the opening of the long hole 68. A pin 72 is inserted.

  The distal end portion of the displacement cam 54 is slightly reduced in diameter, and this reduced diameter distal end portion is inserted into the fixed cam 56. As will be described later, the distal end portion of the displacement cam 54 can project from the end surface of the fixed cam 56 on the pressing cam 58 side. 2A to 2D, a first inclined portion 74 is formed at the distal end portion of the displacement cam 54. As shown in FIG.

  The fixed cam 56 is positioned and fixed by a fixed cam positioning pin 78 (see FIG. 1). In other words, the fixed cam 56 is not displaced within the camshaft 30. As shown in FIG. 2A, a second inclined portion 80 and a depression 81 are formed at the distal end portion of the fixed cam 56.

  The pressing cam 58 has a plurality of protrusions 82 on the end surface facing the displacement cam 54 and the fixed cam 56. A third inclined portion 84 is formed at the tip of the protruding portion 82.

  The other end surface of the pressing cam 58 is formed as a flat surface, and one end surface of the displacement shaft 60 is in contact with this flat surface. A pin hole 86 extending in a direction substantially perpendicular to the longitudinal direction is formed at the other end of the displacement shaft 60, and a driven pin 88 is inserted into the pin hole 86. . The driven pin 88 is connected to a displacement member 90 that is externally fitted near the end of the camshaft 30. Note that splines (both not shown) are formed on the outer peripheral wall of the camshaft 30 and the inner peripheral wall of the displacement member 90, and these splines mesh with each other.

  In the displacement member 90, a second tooth portion 94 as a second engagement portion is formed at a portion facing the EGR cam 36. As will be described later, the second tooth portion 94 meshes with or disengages from the first tooth portion 38 of the EGR cam 36 following the displacement of the displacement shaft 60.

  In the above configuration, the return spring 66 elastically biases the spring receiving washer 64 away from the camshaft 30, and the coil spring 62 elastically biases the displacement shaft 60 toward the pressing cam 58. .

The fixed cam 56, the pressing cam 58, and the displacement member 90 constitute switching means for switching the EGR valve 35 to an operation state or an operation stop state. On the other hand, the solenoid 44, the arm 50, the displacement cam 54, and the displacement shaft 60 are An operating means for operating the switching means is configured. Further, as will be described later, the operation state / operation stop state of the EGR valve 35 is maintained by the displacement cam 54, the fixed cam 56 and the pressing cam 58. That is, they also serve as an operation state maintaining unit and an operation stop state maintaining unit.

  The solenoid 44 is electrically connected to control means (not shown) such as a CPU via a cable 96 for transmitting a control signal. The CPU is further electrically connected to a throttle opening sensor that detects the opening degree of a throttle valve installed inside an intake manifold (not shown), a rotation sensor that detects the rotational speed of the internal combustion engine 12, and the like. .

  The internal combustion engine 12 to which the EGR device 10 according to the first embodiment is attached is basically configured as described above. Next, the function and effect will be described.

  When the internal combustion engine 12 is energized, the camshaft 30 rotates under the action of the cam chain 42 and the cam sprocket 40. Following this, the cams 32 and 34 rotate, and when the peak portion of the cam 34 reaches a predetermined position, the end of the rocker arm presses the exhaust valve 26. As a result, the valve spring contracts and the exhaust valve 26 is separated from the exhaust port. That is, the exhaust port communicates with the combustion chamber 22, and the combusted exhaust gas is stored in the gas storage chamber.

  Further, when the camshaft 30 further rotates and the peak portion of the cam 34 is separated from the end of the rocker arm, the exhaust valve 26 returns to the original position under the elastic action of the extending valve spring, and is seated on the exhaust port. To do. That is, the exhaust port and the combustion chamber 22 are shut off.

  On the other hand, the peak portion of the cam 32 is in a position to press the end of the rocker arm, whereby the valve spring contracts and the intake valve 24 is separated from the intake port. In other words, the intake port and the combustion chamber 22 communicate with each other, and air is introduced into the combustion chamber 22 through the intake port.

  Of course, when the camshaft 30 continues to rotate and the crest of the cam 32 moves away from the end of the rocker arm, the valve spring expands and elastically biases the intake valve 24. As a result, the intake valve 24 returns to the original position and is seated on the intake port, and the intake port and the combustion chamber 22 are shut off.

  Here, FIGS. 2A to 2E are schematic views showing the distal end portions of the displacement cam 54, the fixed cam 56, and the pressing cam 58 developed by 360 °. As shown in FIG. 2A, the protruding portion 82 of the pressing cam 58 is initially located at the bottom of the second inclined portion 80 provided at the tip of the fixed cam 56. Therefore, as shown in FIG. The pressing cam 58 presses the displacement shaft 60. Accordingly, the displacement shaft 60 is displaced in the direction in which the coil spring 62 is compressed, and following this, the displacement member 90 is displaced in the direction away from the EGR cam 36 via the driven pin 88. That is, the second tooth portion 94 is separated from the first tooth portion 38, and therefore the EGR cam 36 does not operate. Therefore, the EGR valve 35 maintains the operation stop state.

  During this process, if the CPU determines that the load of the internal combustion engine 12 is in the middle speed range or the partial range based on electrical information from a throttle opening sensor, a rotation sensor, etc., the CPU Is in the state shown in FIG. That is, the solenoid 44 is energized and the rod 46 is moved backward.

  As the rod 46 moves backward, the arm 50 rotates around the stop shaft 48 as shown in FIG. As a result, the displacement shaft 60 moves forward in the insertion hole 52 of the camshaft 30. Accordingly, as shown in FIGS. 2B and 2C, the displacement cam 54 protrudes from the open end surface of the fixed cam 56 and presses the protruding portion 82 of the pressing cam 58. As a result, the pressing cam 58 slightly rotates, and the third inclined portion 84 of the projecting portion 82 rides on the first inclined portion 74 of the displacement cam 54.

  Next, energization to the solenoid 44 is stopped. Along with this, the rod 46 moves forward, the arm 50 rotates about the stop shaft 48, and the displacement cam 54 moves backward due to the elastic biasing force of the return spring 66. That is, the state shown in FIG. 4 is obtained. At this time, as shown in FIGS. 2D and 2E, the pressing cam 58 slightly rotates, and the third inclined portion 84 of the protruding portion 82 engages with the depression 81 of the fixed cam 56.

  As the third inclined portion 84 engages with the depression 81, the displacement shaft 60 is elastically biased from the coil spring 62. Following this, the displacement member 90 is displaced in a direction approaching the EGR cam 36 while being guided by the spline via the driven pin 88. Finally, the second tooth portion 94 meshes with the first tooth portion 38, and the EGR cam 36 can be rotated. That is, the EGR valve 35 is in an operating state.

  Eventually, even after the energization of the solenoid 44 is stopped, the EGR valve 35 is separated from the EGR port and can be displaced to the combustion chamber 22 side. The exhaust gas is introduced into the combustion chamber 22 and is used for combustion together with air newly introduced through the intake port and fuel newly introduced in the next intake step.

  As described above, when the first tooth portion 38 and the second tooth portion 94 mesh with each other, the EGR valve 35 continuously repeats opening and closing.

  On the other hand, at the time of idling when the opening of the throttle valve is the minimum or when the load is the maximum when the opening is the maximum, the CPU is based on the electrical information from the throttle opening sensor, the rotation sensor, etc. Judged to be in a high load range. In this case, it is not particularly necessary to open the EGR valve 35 and return the exhaust gas to the combustion chamber 22.

  Therefore, the CPU transmits a control signal via the cable 96 and issues a command for “retracting the rod 46” to the solenoid 44. With this control signal, the rod 46 moves backward as shown in FIG.

  Thereafter, contrary to the above, that is, the protrusion 82 of the pressing cam 58 is pressed from the displacement cam 54 in the order of FIGS. 2E to 2D, 2C, 2B and 2A, while the pressing cam 58 is slightly rotated. It operates and rides on the second inclined portion 80 of the fixed cam 56. Accordingly, the state returns to the state shown in FIG. 1, and the EGR valve 35 is maintained in the operation stopped state.

  Of course, also in this case, the energization to the solenoid 44 is stopped after the protruding portion 82 of the pressing cam 58 rides on the second inclined portion 80 of the displacement cam 54. That is, even after the energization of the solenoid 44 is stopped, the EGR valve 35 is kept in the operation stopped state.

  As can be understood from the above, according to the first embodiment, it is possible to energize the solenoid 44 only when the rod 46 is moved backward, and when the operating state of the EGR valve 35 is maintained. There is no particular need to energize the solenoid 44 when maintaining the operation stop state. Therefore, power consumption can be reduced.

As described above, according to the first embodiment, the EGR valve 35 is maintained in the operating state (openable / closable state) according to the load state of the internal combustion engine 12 while having a simple configuration in which only the switching unit and the operating unit are incorporated. On the other hand, the operation state can be switched to the operation stop state (closed maintenance state) and maintained. Of course, it is easy to change from the operation stop state to the operation state.

For example, when the load on the internal combustion engine 12 is small or large, it is expected that the combustion rate is improved by setting the EGR valve 35 to an operation stop state, and occurrence of knocking can be suppressed. .

  In the above-described embodiment, the switching means for switching the EGR valve 35 to the operation state or the operation stop state is constituted by the fixed cam 56, the pressing cam 58 and the displacement member 90, and the operation for operating the switching means. The means is composed of a solenoid 44, an arm 50, a displacement cam 54, and a displacement shaft 60. However, as long as the EGR valve 35 can be changed from the operation state to the operation stop state, and from the operation stop state to the operation state, any means can be used. It may be configured.

Next, a valve operation switching device will be cited as a second embodiment and will be described with reference to FIG. In addition, the same referential mark is attached | subjected to the same component as the component shown by FIGS. 1-4, and the detailed description is abbreviate | omitted.

FIG. 5 is a schematic longitudinal sectional view of a main part of the internal combustion engine 120 to which the valve operation switching device 100 according to the second embodiment is attached.

  First, like the internal combustion engine 12, the internal combustion engine 120 covers and protects the block main body 16 provided with the cylinder 14, the cylinder head 18 connected above the block main body 16, and the upper portion of the cylinder head 18. And a head cover 20. Among these, a piston (not shown) is inserted into the cylinder 14, and a combustion chamber 22 is formed by the upper end surface of this piston and the space covered by the cylinder head 18.

  An intake port for introducing air into the combustion chamber 22 and an exhaust port for exhausting the exhaust gas burned in the combustion chamber 22 are formed inside the cylinder head 18. The intake port is provided with a normally-operated intake valve 122 that is normally opened and closed, and a variable intake valve 124 that is selected to be in either an operation state or an operation stop state, while an exhaust valve 26 is provided in the exhaust port. Arranged.

  Among them, the normally-operated intake valve 122 and the exhaust valve 26 follow the rotational operation of the camshaft 30 when the peaks of the cams 32 and 34 reach predetermined positions. It is displaced to the combustion chamber 22 side under the action. The displaced normally-operated intake valve 122 and exhaust valve 26 return to their original positions under the elastic action of valve springs arranged around each of them.

  The remaining variable intake valve 124 is displaced toward the combustion chamber 22 by a variable intake valve cam 126 provided on the camshaft 30. That is, when the peak portion of the variable intake valve cam 126 reaches a predetermined position, one end portion of the rocker arm is pressed, and accordingly, the rocker arm rotates around its substantially middle portion, Finally, the pressing member provided at the other end of the rocker arm presses the variable intake valve 124. As a result, the variable intake valve 124 is displaced toward the combustion chamber 22 and exhaust gas is introduced into the combustion chamber 22.

  Similar to the normally operating intake valve 122 and the exhaust valve 26, a valve spring is also provided around the variable intake valve 124. The variable intake valve 124 displaced toward the combustion chamber 22 returns to its original position under the elastic action of this valve spring.

In the second embodiment, the variable intake valve 124 is switched to either the operation state or the operation stop state. This switching is performed by switching means including a fixed cam 56, a pressing cam 58, and a displacement member 90. Further, the solenoid 44, the displacement cam 54, and the displacement shaft 60 constitute an operation means for operating the switching means, and further, as will be described later, a variable intake valve by a displacement cam 54, a fixed cam 56, and a pressing cam 58. The operation state / operation stop state 124 is maintained. That is, they also serve as an operation state maintaining unit and an operation stop state maintaining unit.

Of course, the switching unit, the operation state maintaining unit, and the operation stop state maintaining unit are configured in the same manner as in the first embodiment. That is, the displacement cam 54, the fixed cam 56, and the pressing cam 58 are formed with the first inclined portion 74, the second inclined portion 80, the depression 81, and the third inclined portion 84 shown in FIGS. 2A to 2D, respectively. Yes. The one end surface of the displacement shaft 60 is in contact with the flat one end surface of the pressing cam 58.

  A driven pin 88 inserted into a pin hole 86 formed in the displacement shaft 60 is connected to a displacement member 90 that is externally fitted near the end of the camshaft 30. A second tooth portion 94 as a second engagement portion is formed at a portion of the displacement member 90 that faces the variable intake valve cam 126. The second tooth portion 94 meshes with or disengages from the first tooth portion 38 following the displacement of the displacement shaft 60.

  In this case, the rod 46 of the solenoid 44 positioned and fixed to the head cover 20 moves forward and backward so as to press against or separate from one end of the camshaft 30. Control means such as a CPU (not shown) is electrically connected to the solenoid 44 via a cable 96. Thus, the arm 50 (see FIG. 1) is not required because the rod 46 can be brought into direct contact with the one end portion of the camshaft 30, so that the number of parts is reduced.

  Further, the CPU is also electrically connected to a throttle opening sensor that detects the opening of a throttle valve installed inside an intake manifold (not shown), a rotation sensor that detects the rotational speed of the internal combustion engine 120, and the like. .

The internal combustion engine 120 to which the valve operation switching device 100 according to the second embodiment is attached is basically configured as described above. Next, the function and effect will be described.

  When the internal combustion engine 12 is energized, the camshaft 30 rotates under the action of the cam chain 42 and the cam sprocket 40. Following this, the cams 32 and 34 rotate, and when the peak portion of the cam 34 reaches a predetermined position, the end of the rocker arm presses the exhaust valve 26. As a result, the valve spring contracts and the exhaust valve 26 is separated from the exhaust port. That is, the exhaust port communicates with the combustion chamber 22.

  Further, when the camshaft 30 further rotates and the peak portion of the cam 34 is separated from the end of the rocker arm, the exhaust valve 26 returns to the original position under the elastic action of the extending valve spring, and is seated on the exhaust port. To do. That is, the exhaust port and the combustion chamber 22 are shut off.

  On the other hand, the peak portion of the cam 32 is in a position to press the end portion of the rocker arm, whereby the valve spring contracts and the normally operating intake valve 122 is separated from the intake port. In other words, the intake port and the combustion chamber 22 communicate with each other, and air is introduced into the combustion chamber 22 through the intake port.

  Of course, when the camshaft 30 continues to rotate and the peak portion of the cam 32 moves away from the end of the rocker arm, the valve spring expands and elastically biases the normally operating intake valve 122. As a result, the normally operating intake valve 122 returns to the original position and is seated on the intake port, and the intake port and the combustion chamber 22 are shut off.

  In the above process, when the second tooth portion 94 is separated from the first tooth portion 38, the protrusion 82 of the pressing cam 58 is the bottom of the second inclined portion 80 of the fixed cam 56 as shown in FIG. Located in. Therefore, the variable intake valve cam 126 does not rotate, and therefore the operation stop state of the variable intake valve 124 is maintained.

  When the CPU determines that the internal combustion engine 12 is in a high rotation state based on electrical information from a throttle opening sensor, a rotation sensor, etc., the CPU issues a command to the solenoid 44 to the solenoid 44. On the other hand, energization is performed, and the rod 46 is moved backward.

  As the rod 46 moves backward, the displacement shaft 60 moves forward in the insertion hole 52 of the camshaft 30. Accordingly, as shown in FIGS. 2B and 2C, the displacement cam 54 protrudes from the open end surface of the fixed cam 56 and presses the protruding portion 82 of the pressing cam 58. As a result, the pressing cam 58 slightly rotates, and the third inclined portion 84 of the projecting portion 82 rides on the first inclined portion 74 of the displacement cam 54.

  Next, energization to the solenoid 44 is stopped. Accordingly, the rod 46 moves forward, and as a result, the displacement cam 54 moves backward due to the elastic biasing force of the return spring 66. At this time, as shown in FIGS. 2D and 2E, the pressing cam 58 slightly rotates, and the third inclined portion 84 of the protruding portion 82 engages with the depression 81 of the fixed cam 56.

  As the third inclined portion 84 engages with the depression 81, the displacement shaft 60 is elastically biased from the coil spring 62. Following this, the displacement member 90 is displaced in the direction of approaching the variable intake valve cam 126 via the driven pin 88. Finally, the second tooth portion 94 meshes with the first tooth portion 38, and the variable intake valve cam 126 can rotate. That is, the variable intake valve 124 is in an operating state.

  Eventually, even after the energization of the solenoid 44 is stopped, the variable intake valve 124 is separated from the intake port and can be displaced toward the combustion chamber 22, and the mixed gas is introduced into the combustion chamber 22 during the displacement.

  As described above, when the first tooth portion 38 and the second tooth portion 94 are meshed with each other, the variable intake valve 124 continuously opens and closes.

  On the other hand, at the time of idling when the throttle valve opening is minimized, the CPU determines that the engine is in the low rotation range based on electrical information from a throttle opening sensor, a rotation sensor, or the like. In this case, it is not particularly necessary to open the variable intake valve 124 and increase the amount of mixed gas to be taken in.

  Therefore, the CPU transmits a control signal via the cable 96 and issues a command for “retracting the rod 46” to the solenoid 44. The rod 46 moves backward by this control signal.

  Thereafter, contrary to the above, that is, the protrusion 82 of the pressing cam 58 is pressed from the displacement cam 54 in the order of FIGS. 2E to 2D, 2C, 2B and 2A, while the pressing cam 58 is slightly rotated. It operates and rides on the second inclined portion 80 of the fixed cam 56. Accordingly, the state returns to the state shown in FIG. 5, and the variable intake valve 124 is stopped and maintained.

  Of course, also in this case, the energization to the solenoid 44 is stopped after the protruding portion 82 of the pressing cam 58 rides on the second inclined portion 80 of the displacement cam 54. That is, the variable intake valve 124 is kept in an operation stop state even after the energization to the solenoid 44 is stopped.

  As can be understood from the above, also in the second embodiment, it becomes possible to energize the solenoid 44 only when the rod 46 is moved backward, and when the operating state of the variable intake valve 124 is maintained, There is no particular need to energize the solenoid 44 when maintaining the operation stop state. Therefore, power consumption can be reduced.

As described above, according to the second embodiment, the variable intake valve 124 is brought into an operating state (openable / closable state) according to the load state of the internal combustion engine 120 while having a simple configuration in which only the switching unit and the operating unit are incorporated. It can be maintained or switched from the operating state to the operating stop state (closed maintaining state) and maintained. Of course, it is easy to change from the operation stop state to the operation state.

When the variable intake valve 124 is in an operating state during high rotation, a large amount of air is introduced into the combustion chamber 22, so that the output of the internal combustion engine can be improved. On the other hand, when the variable intake valve 124 and the operation is stopped during the low rotation, air is introduced into the combustion chamber 22 only through the normal operation intake valve 12 2, thereby improving it and burning rate of improving the torque It is expected.

  Next, a cam switching device will be described as a third embodiment, which will be described with reference to FIGS. The same components as those shown in FIGS. 1 to 5 are denoted by the same reference numerals, and detailed description thereof is omitted.

FIG. 6 is a schematic vertical sectional view of a main part of an internal combustion engine 202 provided with a cam switching device 200 according to the third embodiment. Similarly to the internal combustion engines 12 and 120, the internal combustion engine 202 is also protected by covering the block main body 16 provided with the cylinder 14, the cylinder head 18 connected above the block main body 16, and the upper portion of the cylinder head 18. And a head cover 20. A combustion chamber 22 is formed by the upper end surface of the piston inserted into the cylinder 14 and the space covered by the cylinder head 18.

  An intake port for introducing air into the combustion chamber 22 and an exhaust port for exhausting the exhaust gas burned in the combustion chamber 22 are formed inside the cylinder head 18. An intake valve 24 is disposed at the intake port, while an exhaust valve 26 is disposed at the exhaust port. The intake valve 24 and the exhaust valve 26 are displaced toward the combustion chamber 22 under the action of the camshaft 210, the intake valve cam 212, the exhaust valve cam 36, the rocker arm, and the pressing member. It is the same as described above that 24 and the exhaust valve 26 return to their original positions under the elastic action of the valve spring.

  Here, the intake valve cam 212 for displacing the intake valve 24 is configured to include a first cam 214 and a second cam 216 adjacent to each other in the same member. As will be described later, either the first cam 214 or the second cam 216 selectively acts on the intake valve 24.

  As can be understood from FIG. 6, the first cam 214 and the second cam 216 have different cam profiles. In this case, the vertical dimension of the second cam 216 is set slightly higher than that of the first cam 214. Accordingly, the lift amount of the intake valve is greater when the second cam 216 is selected than when the first cam 214 is selected.

  An insertion hole 218 is formed along the longitudinal direction of the cam shaft 210, and the distal end portion of the displacement cam 54 is inserted into the insertion hole 218, and the fixed cam 56, the pressing cam 58, and the displacement shaft 60 are provided. Has been inserted. A wide portion 220 is formed at the end of the displacement cam 54 on the arm 50 side, while a spring receiving portion 222 is formed at the end exposed from the insertion hole 218 in the fixed cam 56. A coil spring 224 is seated on the wide portion 220 and the spring receiving portion 222.

  The fixed cam is positioned and fixed by a fixed pin 226.

  A stopper portion 228 is formed on a substantially middle portion of the camshaft 210 so as to protrude outward in the diameter direction. Further, the displacement shaft 60 and the intake valve cam 212 are connected to each other via a connecting pin 230. Here, a long hole (not shown) is formed in the camshaft 210, and the connecting pin 230 is relatively displaced in the long hole.

  A cover member 232 is fitted on the end of the camshaft 210 so as to cover the connecting pin 230. A coil spring 236 is interposed between a step formed on the cover member 232 and a bearing 234 that fixes the camshaft 210.

In the third embodiment, switching from the first cam 214 to the second cam 216, or switching in the opposite direction, is performed by including the fixed cam 56, the pressing cam 58, the displacement shaft 60, and the connecting pin 230. Implemented by means. The solenoid 44, the displacement cam 54, and the displacement shaft 60 constitute an operation means for operating the switching means. Further, the first cam 214 or the second cam is constituted by the displacement cam 54, the fixed cam 56, and the pressing cam 58. The state in which one of the selected ones of 216 acts on the intake valve 24 and the state where the action is stopped are maintained. That is, they also serve as an operation state maintaining unit and an operation stop state maintaining unit.

Of course, the switching unit, the operation state maintaining unit, and the operation stop state maintaining unit are configured in the same manner as in the first embodiment and the second embodiment. That is, the displacement cam 54, the fixed cam 56, and the pressing cam 58 are formed with the first inclined portion 74, the second inclined portion 80, the depression 81, and the third inclined portion 84 shown in FIGS. 2A to 2D, respectively. Yes.

The internal combustion engine 202 provided with the cam switching device 200 according to the third embodiment is basically configured as described above. Next, the operation and effect will be described.

When the internal combustion engine 12 is energized, the camshaft 210 rotates under the action of the cam chain 42 and the cam sprocket 40. Following this, the intake valve cam 32 and the exhaust valve cam 34 rotate. When the peak of the exhaust valve cam 212 reaches a predetermined position, the end of the rocker arm presses the exhaust valve 26. To do. As a result, the valve spring contracts and the exhaust valve 26 is separated from the exhaust port. That is, the exhaust port communicates with the combustion chamber 22.

  When the camshaft 210 further rotates and the peak portion of the exhaust valve cam 34 is separated from the end of the rocker arm, the exhaust valve 26 returns to the original position under the elastic action of the extending valve spring, and the exhaust Sit in the port. That is, the exhaust port and the combustion chamber 22 are shut off.

  On the other hand, the peak portion of the first cam 214 constituting the intake valve cam 32 is in a position to press the end of the rocker arm, whereby the valve spring contracts and the intake valve 24 is separated from the intake port. In other words, the intake port and the combustion chamber 22 communicate with each other, and air is introduced into the combustion chamber 22 through the intake port.

  Of course, when the camshaft 210 continues to rotate and the peak portion of the first cam 214 moves away from the end of the rocker arm, the valve spring expands and elastically biases the intake valve 24. As a result, the intake valve 24 returns to the original position and is seated on the intake port, and the intake port and the combustion chamber 22 are shut off.

  In the above process, as shown in FIG. 2A, the protruding portion 82 of the pressing cam 58 is positioned at the bottom of the second inclined portion 80 of the fixed cam 56. At this time, as described above, the first cam 214 acts on the intake valve 24. As a result, the intake valve 24 is repeatedly displaced and returned by a lift amount corresponding to the cam profile of the first cam 214. This state is maintained by maintaining the OFF state of the solenoid 44.

  Thereafter, when the CPU determines that the internal combustion engine is in a high rotation state based on electrical information from a throttle opening sensor, a rotation sensor, etc., the CPU issues a command to the solenoid 44 and By energizing the rod 46, the rod 46 is moved backward.

  As the rod 46 moves backward, the arm 50 rotates about the stop shaft 48 as shown in FIG. As a result, the displacement shaft 60 moves forward in the insertion hole 218 of the camshaft 210. Accordingly, as shown in FIGS. 2B and 2C, the displacement cam 54 presses the protruding portion 82 of the pressing cam 58 inserted into the open end surface of the fixed cam 56. As a result, the pressing cam 58 slightly rotates, and the third inclined portion 84 of the projecting portion 82 rides on the first inclined portion 74 of the displacement cam 54.

  Next, energization to the solenoid 44 is stopped. Along with this, the rod 46 moves forward, the arm 50 rotates about the stop shaft 48, and the displacement cam 54 moves backward due to the elastic biasing force of the coil spring 224. At this time, as shown in FIGS. 2D and 2E, the pressing cam 58 slightly rotates, and the third inclined portion 84 of the protruding portion 82 engages with the depression 81 of the fixed cam 56.

At the same time, the second cam 216 is displaced to a position corresponding to the position of the intake valve 24. Thus, a state where the intake valve 2 4 is opened and closed under the action of the second cam 216, moreover, to the third inclined portion 84 of the projecting portion 82 is engaged with the recess 81 of the fixed cam 56, the State is maintained.

  Of course, the intake valve 24 is displaced by a lift amount corresponding to the cam profile of the second cam 216. As described above, in this case, the lift amount by the second cam 216 is larger than that of the first cam 214, so that a large amount of air can be introduced into the combustion chamber 22.

  Eventually, even after the energization of the solenoid 44 is stopped, the intake valve 24 can be moved away from the intake port by the lift amount corresponding to the cam profile of the second cam 216 and can be displaced toward the combustion chamber 22 side. Air gas is introduced into the combustion chamber 22.

  On the other hand, at the time of idling when the throttle valve opening is minimized, the CPU determines that the engine is in the low rotation range based on electrical information from a throttle opening sensor, a rotation sensor, or the like. In this case, it is not particularly necessary to introduce a large amount of air into the combustion chamber 22.

  Therefore, the CPU transmits a control signal via the cable 96 and issues a command for “retracting the rod 46” to the solenoid 44. The rod 46 moves backward by this control signal. As a result, the displacement shaft 60 is elastically biased from the coil spring 236.

Thereafter, contrary to the above, that is, the protrusion 82 of the pressing cam 58 is pressed from the displacement cam 54 in the order of FIGS. 2E to 2D, 2C, 2B and 2A, while the pressing cam 58 is slightly rotated. It operates and rides on the second inclined portion 80 of the fixed cam 56. Thus returns to the state shown in FIG. 6, a state of repeating the displacement and return is maintained lift the intake valve 24 corresponding to the cam profile of the first cam 21 4. Incidentally, the cam 21 2 for intake valves are locked dam by the stopper portion 228.

Of course, also in this case, the energization to the solenoid 44 is stopped after the protruding portion 82 of the pressing cam 58 rides on the second inclined portion 80 of the displacement cam 54. That is, the state in which after the energization of the solenoid 44 is stopped even repeated displacement and return in lift the intake valve 24 corresponding to the cam profile of the first cam 21 4 is maintained.

  As described above, by switching the cam acting on the intake valve 24 between the high rotation time and the low rotation time, the output of the internal combustion engine can be improved at the high rotation speed, while the torque can be improved at the low rotation speed. It is expected that the burning rate will be improved.

Claims (5)

An intake valve (24) disposed in an intake port for introducing air into the combustion chamber (22), and an exhaust valve (26) disposed in an exhaust port for exhausting exhaust gas combusted in the combustion chamber (22). An EGR device (10) attached to an internal combustion engine comprising:
An EGR valve (35) disposed in an EGR port for returning the exhaust gas to the combustion chamber (22);
Switching means for switching the EGR valve (35) to an operation state or an operation stop state;
Operating means for operating the switching means;
Have
The switching means includes an operating state maintaining means for maintaining the operating state until the operating state is stopped by the switching means when the operating state is set under the action of the operating means, and an operating stop state under the action of the operating means. And an operation stop state maintaining means for maintaining an operation stop state until the operation state is set by the switching means.
The actuating means is energized only when the EGR valve (35) is switched from the operation state to the operation stop state, or when the EGR valve (35) is switched from the operation stop state to the operation state, and the EGR valve (35) is operated or stopped. a solenoid (44) during the Ru is de-energized to maintain the state,
A displacement cam (54) that is displaced under the action of the solenoid (44);
A displacement shaft (60) that displaces following the displacement of the displacement cam (54);
Have
The switching means includes a fixed cam (56),
A pressing cam (58) whose one end abuts against the tip of either the displacement cam (54) or the fixed cam (56);
A displacement member (90) displaced by the pressing cam (58) following the displacement shaft (60);
Have
The displacement member (90) has a second engagement portion (94) facing a first engagement portion (38) provided in an EGR cam (36) for opening and closing the EGR valve (35),
The second engagement portion (94) is engaged with or disengaged from the first engagement portion (38) following the displacement of the displacement shaft (60),
When the one end of the pressing cam (58) contacts the tip of the fixed cam (56), the second engaging portion (94) is detached from the first engaging portion (38), and the EGR While the valve (35) is brought into an operation stop state, when the one end portion of the pressing cam (58) comes into contact with the distal end portion of the displacement cam (54) which is most retracted, the first engagement portion (38) It said second engagement portion (94) EGR system, wherein to Rukoto and operating conditions the EGR valve (35) engages is (10).   The EGR device (10) according to claim 1, wherein the operation state maintaining means and the operation stop state maintaining means are composed of the same member. The EGR device (10) according to claim 1 or 2 , wherein the displacement shaft (60) and the fixed cam (56) are a camshaft (30) for opening and closing the intake valve (24) and the exhaust valve (26). An EGR device (10), wherein the EGR device (10) is inserted therein. The EGR device (10) according to any one of claims 1 to 3 , further comprising a biasing means (66) for returning the rod (46) of the solenoid (44) to its original position. EGR device (10). A plurality of intake valves (24) disposed in an intake port for introducing air into the combustion chamber (22), and an exhaust valve disposed in an exhaust port for exhausting exhaust gas combusted in the combustion chamber (22). A valve operation switching device (100) attached to an internal combustion engine (120) comprising (26) ,
The intake valve (24) includes a normally-operated intake valve (122) that is always in an operating state, and a variable intake valve (124) that is set to either the operating state or the operation stopped state.
And switching means for switching the variable intake valve (124) to an operating state or an operating stop state;
Operating means for operating the switching means;
Have,
Before SL actuating means, when switching the variable intake valve to (124) stops operation from the operating state or are energized only when switching from operation stop state to the operating state, the variable intake valve (124) is operating conditions or while maintaining the operation stop state and the solenoid (44) that will be de-energized,
A displacement cam (54) that is displaced under the action of the solenoid (44);
A displacement shaft (60) that displaces following the displacement of the displacement cam (54);
Have
The switching means includes a fixed cam (56),
A pressing cam (58) whose one end abuts against the tip of either the displacement cam (54) or the fixed cam (56);
A displacement member (90) displaced by the pressing cam (58) following the displacement shaft (60);
Have
The displacement member (90) has a second engagement portion (94) facing a first engagement portion (38) provided in a variable intake valve cam (126) for opening and closing the variable intake valve (124). Have
The second engagement portion (94) is engaged with or disengaged from the first engagement portion (38) following the displacement of the displacement shaft (60),
When the one end of the pressing cam (58) abuts on the tip of the fixed cam (56), the second engaging portion (94) is detached from the first engaging portion (38) and the variable is achieved. While the intake valve (124) is stopped, the first engagement portion (38) when one end portion of the pressing cam (58) comes into contact with the distal end portion of the displacement cam (54) that is most retracted. and said second engaging portion (94) valve operation switching device, wherein the operating condition and to Rukoto the variable intake valve is engaged (124) (100).

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