JP4925991B2 - EGR device - Google Patents

Description

  The present invention relates to an EGR device 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, Patent Document 1 discloses an internal combustion engine that can increase the pressure and temperature in the combustion chamber with a simple configuration, thereby improving the EGR effect.

  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.

JP 2000-282867 A

  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 extremely small (for example, at 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.

  An object of this invention is to provide the EGR apparatus which can solve the above subjects.

To achieve the above object, the present invention includes an intake valve (30) disposed in an intake port for introducing air (26) into the combustion chamber (24), was burned in the combustion chamber (24) Exhaust An EGR device (10) attached to an internal combustion engine (12) comprising an exhaust valve (32) disposed in an exhaust port (28) for exhausting gas,
A gas storage chamber (70) for storing the exhaust gas;
An EGR valve (72) disposed in an EGR port (68) for returning the exhaust gas from the gas storage chamber (70) to the combustion chamber (24) ;
Control means for determining the load status of the internal combustion engine (12) ;
Based on a command from said control means to determine the load status, operation like Taimata the EGR valve (72) and the EGR valve opening and closing control mechanism for setting to one of the resting state,
It is characterized by having.

  That is, according to the present invention, either the openable / closable state or the closed maintaining state (rest state) is selected according to the load state 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 used for recombustion. On the other hand, the exhaust gas is not introduced into the combustion chamber in the resting state. Therefore, for example, if the EGR valve is deactivated when the load on the internal combustion engine is remarkably small or large, the exhaust gas is not introduced into the combustion chamber at this time, so that the combustion speed is slowed down. Can be avoided. Furthermore, it can be expected that the occurrence of knocking can be suppressed.

  In addition, the EGR valve opening / closing control state and the resting state can be changed only by providing the EGR valve opening / closing control means, so that the configuration is not complicated. For this reason, it can also suppress that cost rises.

Here, EGR valve opening and closing control Organization has said intake valve (30) and an EGR cam is in contact with the camshaft (38) for the opening and closing the exhaust valve (32) (80),
The abutted portion of the cam shaft displaceably fitted on to the camshaft (38) (38) and integrally rotating operation and and the EGR cam (80) (90) can abut a contact portion An urging means (82) having a rotating part (102) provided with (112) and a non-rotating part (104) that does not rotate;
A displacement mechanism for displacing the urging means (82) along the axial direction of the camshaft (38) to abut or separate the abutted portion (90) and the abutting portion (112) ;
Can it to configure so as to have a.

  In this case, there is no need to dispose a rod or the like for changing the EGR valve from the openable / closable state to the resting state or vice versa inside the camshaft. For this reason, it is possible to avoid an increase in the diameter of the camshaft, and in the end, it is possible to avoid an increase in the volume and weight of the EGR device and consequently the internal combustion engine.

Further, the displacement Organization, the non-rotating portion wherein the biasing means (82) comprises a (104) gripping means for gripping the (114, 116), the said gripping means (114, 116) the camshaft (38 ) actuators (128 to displace in the axial direction of) and can you to configure manner having.

  According to the present invention, the EGR valve opening / closing control mechanism is provided, and the EGR valve is changed from the openable / closable state to the resting state or vice versa under the action of the EGR valve opening / closing control mechanism according to the load of the internal combustion engine. I have to. For this reason, depending on the load condition, it is also possible to prevent the exhaust gas from returning to the combustion chamber by putting the EGR valve in a resting state.

  Therefore, when the load of the internal combustion engine is remarkably small or remarkably large, it is possible to expect the combustion rate to be improved by setting the EGR valve to the rest state, and it is possible to suppress the occurrence of knocking.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an EGR device according to the present invention will be described in detail with reference to the accompanying drawings by giving preferred embodiments in relation to an internal combustion engine to which the EGR device is attached.

  FIG. 1 is a schematic vertical sectional view of an essential part of an internal combustion engine 12 equipped with an EGR device 10 according to the present embodiment. FIGS. 2 and 3 are sectional views taken along the line II-II in FIG. Fig. 3 is a sectional view taken along line III-III. The internal combustion engine 12 is mounted on, for example, a vehicle such as an automobile two-wheeled vehicle, and runs the vehicle by burning a mixture of air and fuel.

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

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

  The intake valve 30 and the exhaust valve 32 open and close under the action of the camshaft 38 via rocker arms 34 and 36. That is, cams 40 and 42 are provided on the camshaft 38, and when the crests 40a and 42a of the cams 40 and 42 reach a predetermined position following the rotation of the camshaft 38, By pressing one end of either of the rocker arms 34, 36, either of the rocker arms 34, 36 rotates about its substantially middle abdomen. As a result, as either of the pressing members 44, 46 provided at the other end of the rocker arms 34, 36 presses the intake valve 30 or the exhaust valve 32, the intake valve 30 or the exhaust valve 32 Displacement to the combustion chamber 24 side.

  Valve springs 48 and 50 are arranged around the intake valve 30, and one end portions of these valve springs 48 and 50 are seated on a disk member 52 positioned and fixed in the cylinder head 18, and the other end portion is It sits on a spring receiving member 54 fitted on the tip of the intake valve 30. As the camshaft 38 rotates and the crest 40a of the cam 40 moves away from one end of the rocker arm 34, the valve springs 48 and 50 press the spring receiving member 54 by its elastic action. As a result, the intake valve 30 returns to its original position and eventually sits on the intake port 26.

  Similarly, valve springs 56 and 58 are disposed around the exhaust valve 32, one end of the valve springs 56 and 58 is seated on the disk member 60, and the other end is the tip of the exhaust valve 32. It is seated on a spring receiving member 62 that is externally fitted to the portion. When the camshaft 38 rotates and the crest portion 42a of the cam 42 is separated from the one end portion of the rocker arm 36, the spring receiving member 62 is pressed by the elastic action of the valve springs 56, 58. The exhaust valve 32 returns to its original position and is seated on the exhaust port 28.

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

  An EGR port 68 (see FIG. 3) is formed on the right side of the intake port 26, and the EGR port 68 communicates with a gas storage chamber 70 for storing exhaust gas. An EGR valve 72 is seated on or separated from the EGR port 68.

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

  Here, as shown in FIGS. 1 and 3, the camshaft 38 is further provided with an EGR cam 80 for opening and closing the EGR valve 72. The EGR cam 80 can rotate independently of the camshaft 38. That is, the rotational urging force for the EGR cam 80 is not transmitted from the camshaft 38, but is transmitted only from the urging assembly 82 as urging means, as will be 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 peripheral wall portion along the circumferential direction of the inner peripheral wall portion. Further, the first cam portion 86 is formed on the outer peripheral wall portion so as to bulge, and the first cam portion 86 is spaced from the first cam portion 86 by a predetermined angle (for example, 180 ° crank angle). A second cam portion 88 bulging substantially the same as the one cam portion 86 is formed. Further, a first convex portion 90 as a contacted portion protrudes from the one bottom surface, and the first convex portion 90 is located between the first cam portion 86 and the second cam portion 88. Yes.

  On the other hand, a positioning pin 92 is provided on the camshaft 38, and the positioning pin 92 enters the annular groove 84 provided on the inner peripheral wall portion of the EGR cam 80 (see FIG. 1). Thereby, the EGR cam 80 is prevented from being displaced along the axial direction of the camshaft 38.

  One end of the rocker arm 98 is also in contact with the EGR cam 80. A pressing member 100 is also provided at the other end of the rocker arm 98, and the pressing member 100 is in contact with the upper end of the EGR valve 72.

  The camshaft 38 is further provided with the biasing assembly 82. The biasing assembly 82 includes a disc-shaped inner ring member 102 and an outer ring member 104, and a bearing 106 (see FIG. 1) is interposed between the inner ring member 102 and the outer ring member 104.

  A tooth portion 108 is formed on the inner peripheral wall portion of the inner ring member 102 (see FIGS. 1, 3, and 4), and the tooth portion 108 is formed on the outer peripheral wall near the end of the camshaft 38. Engage with the portion 110. Accordingly, the inner ring member 102 rotates integrally with the camshaft 38 as the camshaft 38 rotates. That is, the inner ring member 102 is a rotating part.

  In the inner ring member 102, a second convex portion 112 as a contact portion protrudes from the bottom surface facing the EGR cam 80 (see FIGS. 1 and 4). As will be described later, the EGR cam 80 rotates when the first convex portion 90 abutting against the second convex portion 112 is pressed from the second convex portion 112.

  On the other hand, since the bearing 106 (see FIG. 1) is interposed between the inner ring member 102 and the outer ring member 104 as described above, the outer ring member 104 does not rotate following the inner ring member 102. . In other words, the outer ring member 104 is a non-rotating part.

  As shown in FIG. 4, the outer ring member 104 has its outer peripheral wall held by a first claw 114 and a second claw 116 as gripping means. The first claw 114 and the second claw 116 have curved portions 118 and 118 that are curved so as to be separated from each other, and the biasing assembly 82 is accommodated between the curved portions 118 and 118. Each of the curved portions 118 and 118 is provided with a screw insertion hole, and the screws 120 and 120 that are passed through the screw insertion holes are screwed into the outer ring member 104, whereby the outer ring member 104 and the first claw 114. And the 2nd nail | claw 116 is connected.

  In addition, the straight portions 122 and 122 of the first claw 114 and the second claw 116 are passed through substantially the middle portion of the pivot 124 in the axial direction. As shown in FIG. 2, the pivot 124 is supported in the cylinder head 18.

  U-shaped notches are formed in the respective square tip portions 126 and 126 of the first claw 114 and the second claw 116, and a rod constituting a solenoid 128 as an actuator is formed in each notch. A stop shaft 132 that locks 130 is passed. The first claw 114 and the second claw 116 (gripping means) and the solenoid 128 constitute a displacement mechanism for displacing the biasing assembly 82 along the axial direction of the camshaft 38.

  Then, as will be described later, the EGR valve 72 can be opened or closed under the action of the displacement mechanism, the EGR cam 80 (see FIGS. 1, 3 and 4), and the biasing assembly 82. Is set. That is, the displacement mechanism, the EGR cam 80, and the urging assembly 82 function as EGR valve opening / closing control means.

  The solenoid 128 is electrically connected to a control means (not shown) such as a CPU via a cable 134 for transmitting a control signal. The CPU is further electrically connected to a throttle opening sensor that detects the opening of a throttle valve installed inside the intake manifold (not shown), a rotation sensor that detects the rotational speed of the internal combustion engine 12, and the like. The

  The internal combustion engine 12 to which the EGR device 10 according to the present 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 cam shaft 38 rotates under the action of the cam chain 66 and the cam sprocket 64. Following this, the cams 40, 42 rotate, and when the peak 42 a of the cam 42 reaches a predetermined position, the end of the rocker arm 36 presses the exhaust valve 32 via the pressing member 46. As a result, the valve springs 56 and 58 contract, and the exhaust valve 32 is separated from the exhaust port 28. That is, the exhaust port 28 communicates with the combustion chamber 24, and the combusted exhaust gas is stored in the gas storage chamber 70 along with this.

  Further, when the camshaft 38 further rotates and the peak portion 42a of the cam 42 is separated from the end portion of the rocker arm 36, the exhaust valve 32 returns to the original position under the elastic action of the extending valve springs 56 and 58. , Seat on the exhaust port 28. That is, the exhaust port 28 and the combustion chamber 24 are shut off.

  On the other hand, the peak portion 40 a of the cam 40 is in a position to press the end of the rocker arm 34, whereby the valve springs 48 and 50 are contracted and the intake valve 30 is separated from the 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, when the camshaft 38 continues to rotate and the crest 40a of the cam 40 moves away from the end of the rocker arm 34, the valve springs 48 and 50 expand to elastically bias the intake valve 30. As a result, the intake valve 30 returns to the original position and is seated on the intake port 26, and the intake port 26 and the combustion chamber 24 are shut off.

  During this time, the inner ring member 102 of the biasing assembly 82 in which the tooth portion 108 meshes with the tooth portion 110 of the camshaft 38 also rotates following the camshaft 38.

  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.

  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 urging assembly 82 are in contact with each other. As described above, since the inner ring member 102 of the biasing assembly 82 is rotating, the first convex portion 90 of the EGR cam 80 is pressed by the second convex portion 112 of the inner ring member 102. As a result, 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 98 pressed by the first cam portion 86 or the second cam portion 88 rotates. The end portion presses the EGR valve 72 via the pressing member 100. As a result, the valve spring 74 is compressed, and the EGR valve 72 is moved away from the EGR port 68 and 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 used for combustion together with the air newly introduced through the intake port 26 and the newly introduced fuel in the next intake step. The

  Of course, when the first cam portion 86 or the second cam portion 88 is separated from the rocker arm 98, the EGR valve 72 returns to the original position by the elastic biasing force of the expanding valve spring 74 and is seated on the EGR port 68.

  As described above, when the first convex portion 90 and the second convex portion 112 are in contact with each other, the EGR valve 72 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 72 and return the exhaust gas to the combustion chamber 24.

  Therefore, the CPU transmits a control signal via the cable 134 and issues a command to the solenoid 128 to “advance the rod 130”. With this control signal, the rod 130 moves forward as shown in FIG.

  Along with this forward movement, the first claw 114 and the second claw 116 whose square end portions 126 and 126 are connected to the rod 130 via the stop shaft 132 rotate about the pivot 124.

  As described above, both the first claw 114 and the second claw 116 are connected to the outer ring member 104 via the screws 120 and 120. Therefore, the outer ring member 104, and thus the entire urging assembly 82, retreats to the right in FIG. 5 along the axial direction of the camshaft 38. Of course, at this time, the biasing assembly 82 is guided to the tooth portion 110 of the camshaft 38. This is because the teeth 108 of the inner ring member 102 mesh with the teeth 110.

  By this backward movement, 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 urging force for the EGR cam 80 is not transmitted, and the rotational operation of the EGR cam 80 is finally stopped. Naturally, the first cam portion 86 and the second cam portion 88 of the EGR cam 80 do not come into contact with the rocker arm 98, so that the EGR valve 72 is pressed from the rocker arm 98 via the pressing member 100. Also disappear. That is, the state in which the EGR valve 72 is seated on the EGR port 68, in other words, the state in which the EGR valve 72 is closed is maintained, and the state in which the combustion chamber 24 and the gas storage chamber 70 are shut off is maintained. In short, the EGR valve 72 is deactivated, so that the exhaust gas is not returned to the combustion chamber 24.

  At this time, the camshaft 38 continues to rotate. For this reason, the inner ring member 102 constituting the biasing assembly 82 continues to rotate. On the other hand, as described above, since the rotational biasing force is not transmitted from the cam shaft 38 to the EGR cam 80, the EGR cam 80 does not rotate. The positioning pin 92 provided on the camshaft 38 is displaced in the annular groove 84. Therefore, the rotation urging force is not transmitted from the positioning pin 92 to the EGR cam 80.

  Further, since the positioning screw is inserted into the annular groove 84, the EGR cam 80 is prevented from being displaced along the axial direction of the cam shaft 38. That is, it is possible to suppress the EGR cam 80 from being displaced.

  When the opening of the throttle valve is changed from this state and the load of the internal combustion engine 12 is in the middle speed range or the partial range, the CPU that has detected that causes the solenoid 128 to “retract the rod 130 through the cable 134. Command. The control signal causes the rod 130 to move backward, and the first claw 114 and the second claw 116 connected to the rod 130 via the stop shaft 132 rotate about the pivot 124. Finally, as shown in FIG. 1, the second convex portion 112 of the inner ring member 102 and the first convex portion 90 of the EGR cam 80 can come into contact with each other. As a result, the rotational biasing force of the inner ring member 102 against the EGR cam 80 is reached. Can be transmitted. That is, the EGR valve 72 can be opened and closed, and the exhaust gas is returned to the combustion chamber 24 when the EGR valve 72 is opened.

  As described above, according to the present embodiment, the load state of the internal combustion engine 12 can be reduced while the simple configuration in which the urging assembly 82 having a portion that contacts or separates from the EGR cam 80 is incorporated. Accordingly, the EGR valve 72 can be opened and closed, or can be kept in a closed state (resting state), and the change from one state to the other is extremely easy.

  For example, when the load of the internal combustion engine 12 is remarkably small or remarkably large, it is expected that the combustion rate is improved by putting the EGR valve 72 in a resting state, and the occurrence of knocking is suppressed. it can.

  In the above-described embodiment, the EGR valve opening / closing control means for controlling the EGR valve 72 to either the openable / closable state or the resting state is constituted by the EGR cam 80, the biasing assembly 82, and the displacement mechanism. However, any configuration may be used as long as the EGR valve 72 can be changed from the openable / closable state to the resting state and from the resting state to the openable / closable state.

  The actuator may be a cylinder mechanism.

It is a principal part schematic longitudinal cross-sectional view of the internal combustion engine with which the EGR apparatus which concerns on this Embodiment was attached. It is the II-II sectional view taken on the line of FIG. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 1. FIG. 2 is a schematic exploded perspective view showing an EGR cam, an urging assembly, a first claw, and a second claw constituting the EGR device of FIG. 1. FIG. 2 is a schematic vertical sectional view of an essential part when an EGR valve is in a resting state in the internal combustion engine of FIG. 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... EGR apparatus 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 ... mountain 64 ... cam sprocket 66 ... cam chain 68 ... EGR port 70 ... gas storage chamber 72 ... EGR valve 80 ... EGR cam 82 ... biasing assembly 86, 88 ... cam 90 ... 1st convex part 92 ... Positioning pin 102 ... Inner ring member 104 ... Outer ring member 106 ... Bearing 108, 110 ... Tooth part 112 ... Second convex part 114, 116 ... Claw 128 ... Solenoid 130 ... Rod 132 ... Stop shaft 134 ... Cable

Claims (1)

An intake valve disposed in an intake port (26) for introducing air into the combustion chamber (24) (30) is disposed in the exhaust port (28) for exhausting exhaust gas burned in the combustion chamber (24) An EGR device (10) attached to an internal combustion engine (12) comprising an exhaust valve (32) ,
A gas storage chamber (70) for storing the exhaust gas;
An EGR valve (72) disposed in an EGR port (68) for returning the exhaust gas from the gas storage chamber (70) to the combustion chamber (24) ;
Control means for determining the load status of the internal combustion engine (12) ;
Based on a command from said control means to determine the load status, operation like Taimata the EGR valve (72) and the EGR valve opening and closing control mechanism for setting to one of the resting state,
I have a,
The EGR valve opening / closing control mechanism includes an EGR cam (80) in contact with a camshaft (38) for opening and closing the intake valve (30) and the exhaust valve (32);
A contact portion that is detachably fitted to the cam shaft (38), rotates integrally with the cam shaft (38), and can contact the contact portion (90) of the EGR cam (80). An urging means (82) comprising a rotating part (102) provided with (112) and a non-rotating part (104) that does not rotate;
A displacement mechanism for displacing the urging means (82) along the axial direction of the camshaft (38) to abut or separate the abutted portion (90) and the abutting portion (112);
With
Further, the displacement mechanism includes gripping means (114, 116) for gripping the non-rotating part (104) included in the biasing means (82),
An actuator (128) for displacing the gripping means (114, 116) along the axial direction of the camshaft (38);
EGR apparatus characterized by have a (10).

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