KR20090032945A - Egr system - Google Patents

Abstract

An EGR apparatus is provided to improve combustion speed by setting up an EGR valve in a dormant state in case the load of the internal combustion engine is remarkably low or remarkably high. An EGR apparatus comprises an EGR cam(80) installed at a cam shaft. The EGR cam independently rotates to the cam shaft. A first convex part(90) is protruded in one bottom surface. A pressing assembly(82) is installed at the cam shaft. The pressing assembly comprises: a second convex part(112); an inner wheel member(102) which rotates in the cam shaft; and an outer wheel member(104) connected to a rod(130) of a solenoid(128) through a first claw and a second claw. The inner wheel member rotates according to the cam shaft. The inner wheel member rotates in case the second convex part is contacted to the first convex part.

Description

EBR device {EGR SYSTEM}

The present invention relates to an EGR device attached to an internal combustion engine.

Background Art Conventionally, internal combustion engines in which an exhaust gas recirculation (EGR) device for returning a part of exhaust gas to a combustion chamber are installed. For example, Patent Document 1 discloses an internal combustion engine that has a simple configuration and is capable of raising the pressure and temperature in the combustion chamber, whereby the EGR effect is improved.

In the internal combustion engine described in Patent Document 1, the exhaust gas exhausted through the exhaust port is accumulated in the gas storage chamber, and the exhaust gas is returned to the combustion chamber at the time of the compression process or the like. That is, in the compression process or the like, the EGR valve provided in the EGR port is opened, and as a result, the gas storage chamber and the combustion chamber communicate with each other, so that the exhaust gas in the gas storage chamber is introduced into the combustion chamber. The exhaust gas introduced into the combustion chamber is combusted with a mixed gas of air and fuel.

Thus, the internal combustion engine which recombusts exhaust gas has the advantage that the amount of NOx contained in exhaust gas is smaller than the internal combustion engine which is not equipped with EGR apparatus.

[Patent Document 1] Japanese Unexamined Patent Publication No. 2000-282867

By the way, the internal combustion engine as described above is preferably configured such that the combustion speed is not delayed even when the exhaust gas is returned to the combustion chamber when the load of the internal combustion engine is remarkably small (for example, at idling). In addition, even when air is introduced into the combustion chamber at the maximum amount, a configuration capable of suppressing knocking from occurring is desired.

An object of the present invention is to provide an EGR device capable of solving the above problems.

In order to achieve the above object, the present invention provides an EGR apparatus installed in an internal combustion engine having an intake valve provided in an intake port for introducing air into the combustion chamber, and an exhaust valve provided in an exhaust port for exhausting the exhaust gas combusted in the combustion chamber. as,

A gas storage chamber for storing the exhaust gas;

An EGR valve provided at an EGR port for returning the exhaust gas from the gas storage chamber to the combustion chamber;

Control means for determining a load situation of the internal combustion engine, and

On the basis of the instruction from the control means which judged the load condition, the EGR valve can be opened and closed continuously, and the gas storage chamber and the combustion chamber are continuously connected or blocked, or the EGR valve is closed. And an EGR valve opening / closing control mechanism which is set to any one of a state in which the gas storage chamber and the combustion chamber are blocked.

That is, according to the present invention, either the openable or closed state (stop state) of the EGR valve is selected according to the load situation of the internal combustion engine. In the openable state, the exhaust gas is introduced into the combustion chamber when the EGR valve is opened, and is reburned. On the other hand, in the resting state, the exhaust gas is not introduced into the combustion chamber. Therefore, for example, when the EGR valve is placed at rest when the load of the internal combustion engine is significantly small or significantly large, since the exhaust gas is not introduced into the combustion chamber at this time, it is possible to avoid a delay in the combustion speed. In addition, it can be expected that knocking can be suppressed.

In addition, since the EGR valve opening and closing state and the rest state can be changed only by providing the EGR valve opening and closing control means, the configuration is not complicated. For this reason, cost can also be suppressed from becoming high.

Here, as an example of an EGR valve opening / closing control mechanism, the EGR cam which contacts the cam shaft which opens and closes the said intake valve and the said exhaust valve,

Pressing means including a rotating part which is inserted into the cam shaft so as to be displaceable from the outside and integrally rotates with the cam shaft and is in contact with the contacted part of the EGR cam, and a non-rotating part that does not rotate;

And a displacement mechanism for displacing the pressing means along the axial direction of the cam shaft to contact or separate the contacted portion from the contact portion.

In this case, a rod or the like for changing the EGR valve from the openable state to the idle state or vice versa does not need to be provided inside the camshaft. For this reason, larger diameter of a camshaft is avoided, and eventually, larger volume and weight of an EGR apparatus and further an internal combustion engine can be avoided.

Moreover, as an example of the said displacement mechanism, the structure containing the holding means which grips the non-rotation part with which the said pressing means is equipped, and the actuator which displaces the said holding means along the axial direction of the said camshaft, is mentioned. .

According to the present invention, the EGR valve opening / closing control mechanism is provided, and the EGR valve is changed from the openable state to the idle state or vice versa under the action of the EGR valve opening / closing control mechanism in accordance with the load of the internal combustion engine. For this reason, depending on the load situation, it is also possible to make an EGR valve rest and not to return exhaust gas to a combustion chamber.

Therefore, when the load of the internal combustion engine is remarkably small or remarkably large, the EGR valve can be rested to increase the combustion speed, and knocking can be suppressed.

EMBODIMENT OF THE INVENTION Hereinafter, the EGR apparatus which concerns on this invention is described in detail with reference to attached drawing, based on preferred embodiment in relationship with the internal combustion engine in which the EGR apparatus was attached.

Fig. 1 is a schematic longitudinal sectional view of a main part of an internal combustion engine 12 in which an EGR device 10 according to the present embodiment is installed, and Figs. 2 and 3 are each taken along the line II-II in Fig. 1 in the direction of the arrow. This is a cross sectional view taken along the line III-III and viewed from the arrow direction. The internal combustion engine 12 is mounted in a vehicle such as an automobile motorcycle, for example, to drive the vehicle by burning a mixture of air and fuel.

The combustion engine 12 includes a block main body 16 provided with a cylinder 14, a cylinder head 18 connected above the block main body 16, and a head that covers and protects an upper portion of the cylinder head 18. The cover 20 is provided.

A piston 22 is inserted into the cylinder 14, which is connected to a crankshaft (all not shown) via a connecting rod. The combustion chamber 24 is formed by the upper end surface of this piston 22 and the space covered by the cylinder head 18.

As shown in FIG. 2, in the cylinder head 18, an intake port 26 communicated with an intake manifold (not shown) for introducing air into the combustion chamber 24, and in the combustion chamber 24. An exhaust port 28 is formed in communication with an exhaust manifold (not shown) for exhausting the combusted exhaust gas. An intake valve 30 is provided in the intake port 26, while an exhaust valve 32 is provided in the exhaust port 28.

These intake valves 30 and exhaust valves 32 are opened and closed under the action of the camshaft 38 via the rocker arms 34 and 36. In other words, the cam shafts 38 are provided with cams 40 and 42, and following the rotation of the cam shafts 38, the peaks 40a and 42 of the cams 40 and 42 are rotated. When 42a) reaches a predetermined position, by pressing one end of either of the rocker arms 34 and 36, one of the rocker arms 34 and 36 rotates about its approximately intermediate portion. As a result, any one of the pressing members 44, 46 provided at the other ends of the rocker arms 34, 36 presses the intake valve 30 or the exhaust valve 32, so that the intake valve 30 or The exhaust valve 32 is displaced to the combustion chamber 24 side.

Further, valve springs 48 and 50 are provided around the intake valve 30, and one end of these valve springs 48 and 50 is seated on the disk member 52 positioned and fixed within the cylinder head 18. The other end is seated on the spring support member 54 fitted to the outside of the front end of the intake valve 30. As the cam shaft 38 rotates and the peak portion 40a of the cam 40 is separated from one end of the rocker arm 34, the valve springs 48 and 50 are spring-loaded members ( 54). As a result, the intake valve 30 returns to its original position and eventually sits on the intake port 26.

Similarly to the exhaust valve 32, valve springs 56 and 58 are provided around it, one end of these valve springs 56 and 58 is seated on the disk member 60, and the other end thereof is the exhaust valve 32. ) Is seated on a spring support member 62 fitted to the outside of the tip end. When the cam shaft 38 is rotated so that the peak 42a of the cam 42 is separated from one end of the rocker arm 36, the spring bearing member 62 is caused by the elastic action of the valve springs 56 and 58 accordingly. ) Is pressurized, and as a result, the exhaust valve 32 is returned to its original position and seated in the exhaust port 28.

Here, the cam sprocket 64 is connected to one end of the cam shaft 38 (see FIG. 1). The cam shaft 38 rotates as the cam chain 66 wound around the cam sprocket 64 is driven.

The EGR port 68 (refer FIG. 3) is formed in the right side of the intake port 26, The gas storage chamber 70 which stores waste gas communicates with this EGR port 68. As shown in FIG. The EGR valve 72 seats or separates from this EGR port 68.

Similar to the intake valve 30 and the exhaust valve 32, a valve spring 74 is provided around the EGR valve 72 (see FIG. 3). One end of the valve spring 74 is seated on the disc member 76 positioned and fixed in the cylinder head 18, and the other end is seated on the spring support member 78 fitted outside the tip end of the EGR valve 72. It is.

1 and 3, the cam shaft 38 is further provided with an EGR cam 80 for opening and closing the EGR valve 72. Moreover, this EGR cam 80 is rotatable independently of the cam shaft 38. That is, the rotational pressing force on the EGR cam 80 is not transmitted from the camshaft 38, but only from the pressing assembly 82, which is the pressing means, as described later.

As shown in FIG. 4, the EGR cam 80 has a substantially annular shape, and an annular groove 84 is formed in the inner circumferential wall portion along the circumferential direction of the inner circumferential wall portion. Further, the first cam portion 86 is formed on the outer circumferential wall portion, and the first cam portion 86 is located at a position separated from the first cam portion 86 at a predetermined angle (for example, 180 ° at the crank angle). An expanded second cam portion 88 is formed in substantially the same manner. Moreover, the 1st convex part 90 as a to-be-contacted part protrudes from one bottom face, and the 1st convex part 90 is located between the 1st cam part 86 and the 2nd cam part 88. As shown in FIG.

On the other hand, the positioning pin 92 is provided in the cam shaft 38, and the positioning pin 92 enters the annular groove 84 provided in the inner circumferential wall of the EGR cam 80 (Fig. 1). Reference). As a result, displacement of the EGR cam 80 along the axial direction of the cam shaft 38 is prevented.

One end of the rocker arm 98 also comes into contact with the EGR cam 80. And the press member 100 is provided also in the other end part of this rocker arm 98, This press member 100 contact | connects the upper end part of the EGR valve 72. As shown in FIG.

In addition, the press assembly 82 is installed on the cam shaft 38. The pressing assembly 82 includes a disk-shaped inner ring member 102 and an outer ring member 104, and a bearing 106 (see FIG. 1) is provided between the inner ring member 102 and the outer ring member 104. Intervened.

A tooth portion 108 is formed in the inner circumferential wall portion of the inner ring member 102 (see FIGS. 1, 3, and 4), and the tooth portion 108 is formed on the outer circumferential wall near the end of the cam shaft 38. Meshes with the formed tooth 110. Thus, as the cam shaft 38 rotates, the inner ring member 102 rotates integrally with the cam shaft 38. That is, the inner ring member 102 is a rotating part.

In the inner ring member 102, the second convex part 112 as a contact part protrudes from the bottom face of the side facing the EGR cam 80 (refer FIG. 1 and FIG. 4). As described later, the EGR cam 80 rotates by pressing the first convex portion 90 in contact with the second convex portion 112 from the second convex portion 112.

On the other hand, since the bearing 106 (refer FIG. 1) is interposed between the inner ring member 102 and the outer ring member 104 as described above, the outer ring member 104 rotates in accordance with the inner ring member 102. There is nothing to do. In other words, the outer ring member 104 is a non-rotating portion.

As shown in FIG. 4, the outer ring member 104 is gripped by the 1st claw 114 and the 2nd claw 116 as the outer peripheral wall as a holding means. These first claws 114 and second claws 116 have curved portions 118 and 118 that are curved to separate from one another, and the compression assembly 82 is received between the curved portions 118 and 118. . Each of the curved portions 118 and 118 is provided with a screw insertion through hole, and the screws 120 and 120 passing through the screw insertion through holes are screwed into the outer ring member 104, whereby the outer ring member 104 and the first portion are screwed. The claw 114 and the second claw 116 are connected.

In addition, each of the linear portions 122 and 122 of the first claw 114 and the second claw 116 passes through an approximately intermediate portion in the axial direction of the pivot 124. 2, the pivot 124 is supported in the cylinder head 18. As shown in FIG.

In addition, U-shaped notches are formed at the square tip ends 126 and 126 of the first claw 114 and the second claw 116, respectively, and each notch has a solenoid 128 as an actuator. A fixed shaft 132 for locking the rod 130 constituting the () is passed. The displacement mechanism for displacing the pressing assembly 82 along the axial direction of the camshaft 38 by these first claws 114 and the second claws 116 (holding means) and the solenoid 128. Is composed.

And, as will be described later, under the action of the displacement mechanism, the EGR cam 80 (see FIGS. 1, 3, and 4) and the pressing assembly 82, the EGR valve 72 is in an openable state or in an idle state. It is set to either. That is, these displacement mechanisms, the EGR cam 80 and the press assembly 82 function as the EGR valve opening and closing control means.

The solenoid 128 is electrically connected to control means, for example, a CPU, not shown, via a cable 134 for transmitting a control signal. The CPU is also electrically connected to a throttle opening degree sensor for detecting the opening degree of the throttle valve provided inside the intake manifold (not shown), a rotation sensor for detecting the rotation speed of the internal combustion engine 12, and the like.

The internal combustion engine 12 in which the EGR apparatus 10 which concerns on this embodiment was attached is comprised basically as mentioned above, and the operation effect is demonstrated below.

When the internal combustion engine 12 is pressed, the cam shaft 38 rotates under the action of the cam chain 66 and the cam sprocket 64. Following this, the cams 40 and 42 are rotated, and when the peak portion 42a of the cam 42 reaches a predetermined position, the end of the rocker arm 36 passes through the pressure member 46 to release the exhaust valve ( Press 32). As a result, the valve springs 56 and 58 are contracted, and the exhaust valve 32 is separated from the exhaust port 28. That is, the exhaust port 28 communicates with the combustion chamber 24, whereby the burned exhaust gas is stored in the gas storage chamber 70.

Further, when the cam shaft 38 is further rotated so that the peak portion 42a of the cam 42 is separated from the end of the rocker arm 36, the exhaust valve ( 32 returns to its original position and is seated in the exhaust port 28. That is, the exhaust port 28 and the combustion chamber 24 are cut off.

On the other hand, the peak portion 40a of the cam 40 is in a position to press the end of the rocker arm 34, whereby the valve springs 48, 50 are contracted and the intake valve 30 is intake port ( 26). In other words, the intake port 26 and the combustion chamber 24 communicate with each other, and air is introduced into the combustion chamber 24 through the intake port 26.

Of course, if the peak portion 40a of the cam 40 is separated from the end of the rocker arm 34 by the cam shaft 38 continuously rotating, the valve springs 48 and 50 extend to extend the intake valve 30. Press on the bullet. As a result, the intake valve 30 returns to its original position and is seated at the intake port 26, whereby the intake port 26 and the combustion chamber 24 are blocked.

In the meantime, the inner ring member 102 of the pressing assembly 82 in which the toothed portion 108 meshes with the toothed portion 110 of the camshaft 38 also follows the camshaft 38 and rotates.

During this process, if the CPU determines that the load of the internal combustion engine 12 is in the intermediate speed region or the partial open region based on electrical information from a throttle opening sensor, a rotation sensor, or the like, the CPU may perform the solenoid 128. An instruction is sent to the state shown in FIG.

In this case, as shown in FIG. 1, the first convex portion 90 of the EGR cam 80 and the second convex portion 112 of the pressing assembly 82 contact each other. As described above, since the inner ring member 102 of the pressing assembly 82 is rotating, the first convex portion 90 of the EGR cam 80 is the second convex portion 112 of the inner ring member 102. Pressurized by). Thereby, the EGR cam 80 also rotates.

When the first cam portion 86 or the second cam portion 88 of the rotating EGR cam 80 reaches a predetermined position, the rocker arm pressed by the first cam portion 86 or the second cam portion 88 ( 98 rotates, and the end part pressurizes the EGR valve 72 via the pressurizing member 100. As a result, the valve spring 74 is compressed, and the EGR valve 72 is separated from the EGR port 68 and is displaced toward the combustion chamber 24. As a result, the combustion chamber 24 and the gas storage chamber 70 communicate with each other. Therefore, the exhaust gas stored in the gas storage chamber 70 is introduced into the combustion chamber 24, and is combusted together with the air newly introduced through the intake port 26 and the newly introduced fuel in the next intake process.

Of course, when the 1st cam part 86 or the 2nd cam part 88 is isolate | separated from the rocker arm 98, the EGR valve 72 will return to an original position by the shot force of the valve spring 74 which expands, and EGR Is seated in port 68.

As mentioned above, when the 1st convex part 90 and the 2nd convex part 112 contact each other, the EGR valve 72 repeats opening and closing continuously.

On the other hand, at idling when the opening of the throttle valve is at a minimum or at a maximum load at which the opening is at a maximum, the CPU loads a low load region or a high load based on electrical information from a throttle opening sensor or a rotation sensor. Judging from the area. In this case, it is not particularly necessary to open the EGR valve 72 to return the exhaust gas to the combustion chamber 24.

Thus, the CPU transmits a control signal through the cable 134 and sends a command to the solenoid 128 to advance the rod 130. By this control signal, as shown in FIG. 5, the rod 130 moves forward.

According to this forward operation, the first claw 114 and the second claw 116 whose square end portions 126 and 126 are connected to the rod 130 via the fixed shaft 132 are centered around the pivot 124. Rotation is performed.

As described above, both the first claw 114 and the second claw 116 are connected to the outer ring member 104 via screws 120 and 120. Therefore, the outer ring member 104, and further, the pressing assembly 82 as a whole, retreats to the right side in FIG. 5 along the axial direction of the cam shaft 38. Of course, at this time, the pressing assembly 82 is guided to the teeth 110 of the camshaft 38. This is because the toothed portion 108 of the inner ring member 102 meshes with the toothed portion 110.

By this retraction operation, the second convex portion 112 of the inner ring member 102 is separated from the first convex portion 90 of the EGR cam 80. Therefore, the rotational pressing force with respect to the EGR cam 80 is not transmitted, and finally the rotation operation of the EGR cam 80 is stopped. Naturally, the first cam portion 86 and the second cam portion 88 of the EGR cam 80 also do not come into contact with the rocker arm 98, so that the EGR valve 72 is pushed through the pressing member 100. Pressurization from the rocker arm 98 is also eliminated. That is, the state in which the EGR valve 72 is seated in the EGR port 68, in other words, the state in which the EGR valve 72 is closed is maintained, and eventually the combustion chamber 24 and the gas storage chamber 70 are blocked. maintain. In other words, the EGR valve 72 is at rest, so that the exhaust gas is not returned to the combustion chamber 24.

At this time, the cam shaft 38 continues the rotation operation. For this reason, the inner ring member 102 which comprises the pressing assembly 82 continues a rotation operation. On the other hand, as described above, since the rotational pressing force is not transmitted from the cam shaft 38 to the EGR cam 80, the EGR cam 80 does not rotate. Moreover, the positioning pin 92 provided in the cam shaft 38 displaces the inside of the annular groove 84. Therefore, rotational pressing force is not transmitted from the positioning pin 92 to the EGR cam 80.

In addition, since the positioning screw is inserted into the annular groove 84, the displacement of the EGR cam 80 along the axial direction of the cam shaft 38 is avoided. That is, it is also possible to suppress that the position of the EGR cam 80 shifts.

From this state, when the opening degree of the throttle valve is changed, and the load of the internal combustion engine 12 becomes the intermediate speed region or the partial opening region, the CPU that detects it sends the solenoid 128 to the solenoid 128 through the cable 134. Return the rod 130 ”. The rod 130 is retracted by this control signal, and the first claw 114 and the second claw 116 connected to the rod 130 through the fixed shaft 132 are centered around the pivot 124. Rotate operation. Finally, as shown in FIG. 1, the 2nd convex part 112 of the inner ring member 102 and the 1st convex part 90 of the EGR cam 80 become contactable, and eventually to the EGR cam 80. FIG. The rotational pressing force of the inner ring member 102 with respect to can be transmitted. That is, when the EGR valve 72 is opened and closed and the EGR valve 72 is opened, the exhaust gas is returned to the combustion chamber 24.

As described above, according to the present embodiment, it is a simple configuration that only includes the pressing assembly 82 having a portion contacting or separating from the EGR cam 80, and according to the load situation of the internal combustion engine 12, the EGR The valve 72 can be opened or closed, or it can be made a closed state (stopped state), and it is also very easy to change from one state to the other.

And when the load of the said internal combustion engine 12 is remarkably small or remarkably large, for example, when the EGR valve 72 is set to rest state, a combustion speed is expected to improve and it can suppress generation | occurrence | production of knocking.

In addition, in the above-described embodiment, the EGR valve opening / closing control means for controlling the EGR valve 72 to either the openable state or the idle state is constituted by the EGR cam 80, the pressing assembly 82, and the displacement mechanism. However, as long as the EGR valve 72 can be changed from the openable state to the rest state and the open state from the open state, it may be of any configuration.

In addition, the actuator may be a cylinder mechanism.

1 is a schematic longitudinal sectional view of an essential part of an internal combustion engine in which an EGR device according to the present embodiment is installed.

FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1 and viewed from the arrow direction. FIG.

3 is a cross-sectional view taken along the line III-III of FIG. 1 and viewed from the arrow direction.

FIG. 4 is a schematic exploded perspective perspective view showing an EGR cam, a pressing assembly, a first claw, and a second claw constituting the EGR device of FIG. 1.

FIG. 5 is a schematic longitudinal cross-sectional view of an essential part of the internal combustion engine of FIG. 1 when the EGR valve is in a resting state. FIG.

<Explanation of symbols for the main parts of the drawings>

10: EGR device 12: internal combustion engine

14: cylinder 18: cylinder head

22: piston 24: combustion chamber

26: intake port 28: exhaust port

30: intake valve 32: exhaust valve

34, 36, 98: rocker arm 38: camshaft

40, 42: cam 40a, 42a: pregnant woman

64: cam sprocket 66: cam chain

68: EGR port 70: gas reservoir

72: EGR valve 80: EGR cam

82: press assembly 86, 88: cam portion

90: first convex portion 92: positioning pin

102: inner ring member 104: outer ring member

106: bearing 108, 110: tooth part

112: second convex portion 114, 116: claw

128: solenoid 130: rod

132: fixed shaft 134: cable

Claims (3)

An EGR apparatus attached to an internal combustion engine having an intake valve provided in an intake port for introducing air into a combustion chamber and an exhaust valve provided in an exhaust port for exhausting the exhaust gas combusted in the combustion chamber, A gas storage chamber for storing the exhaust gas; An EGR valve provided at an EGR port for returning the exhaust gas from the gas storage chamber to the combustion chamber; Control means for determining a load situation of the internal combustion engine, and On the basis of the instruction from the control means which has judged the load condition, the EGR valve can be continuously opened and closed to continuously communicate or shut off the gas storage chamber and the combustion chamber, or the EGR valve is abolished. (Iii) an EGR valve opening / closing control mechanism which is set to any one of states in which the gas storage chamber and the combustion chamber are blocked. EGR apparatus comprising a. The method according to claim 1, wherein the EGR valve opening and closing control mechanism, An EGR cam in contact with the cam shaft for opening and closing the intake valve and the exhaust valve; Pressing means including a rotating part which is displaced from the outer side of the cam shaft so as to be integrally rotatable with the cam shaft and in contact with the contacted part of the EGR cam, and a non-rotating part that does not rotate; Displacement mechanism for displacing the pressing means along the axial direction of the cam shaft to contact or separate the contacted portion from the contact portion EGR apparatus comprising a. The said displacement mechanism includes a holding means for holding a non-rotating part with which the said pressing means is equipped, and an actuator which displaces the holding means along the axial direction of the camshaft. EGR device.

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