JP2012067645A - Evaporative fuel control apparatus of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an evaporative fuel control apparatus which has a simplified structure, thereby achieving reduction in the number of assembly steps and which causes evaporative fuel to be combusted reliably and efficiently.SOLUTION: In the evaporative fuel control apparatus 10, a first passage 48 of a bypass conduit 40 is connected between an upstream side of an intake passage 24b and a switching valve 42, and second passages 50a to 50d interconnect the switching valve 42 and downstream sides of intake passages 24a to 24d, whereas a purge conduit 46 to which the evaporative fuel is supplied is connected to the switching valve 42. The switching valve 42 is operated responsive to a driven state of an internal combustion engine 12, thus switching between a communication state between the first passage 48 and the second passages 50a to 50d, and a communication state between the purge conduit 46 and the second passages 50a to 50d, such that intake air or the evaporative fuel is made to flow to the intake passages 24a to 24d.

Description

  The present invention relates to an evaporative fuel control device for an internal combustion engine for circulating evaporative fuel evaporated from fuel to the internal combustion engine in an internal combustion engine mounted on a vehicle.

  2. Description of the Related Art Conventionally, an evaporative fuel control apparatus is known in which evaporative fuel generated in a vehicle fuel tank is adsorbed by a canister and evaporative fuel desorbed from the canister is purged to an intake system of an internal combustion engine.

  For example, in this evaporative fuel control device, a first purge pipe is connected to the downstream side of the canister to correspond to a multi-cylinder internal combustion engine, and the bifurcated second purge pipe branched to the downstream side of the first purge pipe. And four third purge pipes branched in a bifurcated manner are connected to the downstream side of the second purge pipe, and the third purge pipes are connected to throttle bodies each having a throttle valve. . The evaporated fuel desorbed from the canister is supplied to the four throttle bodies through the first to third purge pipes, respectively, and purged to the internal combustion engine (see, for example, Patent Document 1).

  However, in the evaporative fuel control apparatus as described above, when assembling the internal combustion engine, the assembling work between the plurality of first to third purge pipes is very complicated, and the third purge pipe is throttled. Since a joint for connecting to the body is also required, there is a problem that the assembly efficiency of the evaporated fuel control device is lowered and the productivity is deteriorated.

  Therefore, in order to simplify the complicated piping configuration and improve the assembly efficiency, it is assumed that the engine piping configuration disclosed in Patent Document 2 is applied to the evaporated fuel control device. In this engine, a bypass flow path is connected to a surge tank into which intake air is introduced, a downstream side of the bypass flow path is branched and connected to an intake manifold, and a vapor tank for storing fuel The middle of the bypass flow path is connected by a vent passage. In addition, a control valve is provided on the downstream side of the connection portion to which the vent passage is connected in the bypass passage, and the valve is opened to the idle state of the internal combustion engine, and the intake air is supplied to the intake manifold through the bypass passage. It is distributed.

JP-A-4-342863 JP 2000-186653 A

  However, in the piping system disclosed in Patent Literature 2, it is possible to simplify the piping configuration as compared with the configuration of Patent Literature 1, but a control valve for controlling intake air includes Since the purge gas vaporized in the vapor tank is circulated to the intake manifold through the vent passage and the bypass passage, it can be circulated only in the idling state of the internal combustion engine because it is provided downstream of the connection site in the bypass passage. It can be distributed during normal operation.

  The present invention has been made in consideration of the above-mentioned problems, and is intended to reduce the number of assembling steps by simplifying the configuration, and can evaporate the evaporated fuel with certainty and efficiency. An object is to provide a control device.

In order to achieve the above object, the present invention provides an internal combustion engine having an intake passage for supplying intake air to a plurality of cylinder chambers and a throttle valve provided in the intake passage for controlling the flow rate of the intake air. An evaporative fuel control apparatus for supplying vaporized evaporative fuel to the cylinder chamber through the intake passage;
A bypass passage comprising an upstream passage connected to the upstream side of the throttle valve in the intake passage, and a plurality of downstream passages connected to the downstream side of the throttle valve in the intake passage;
A body connected to the bypass passage; a valve body provided inside the body so as to be displaceable; and a drive unit that displaces the valve body along an axial direction. A switching valve capable of switching the communication state of the passage,
A purge passage connected to the switching valve and through which the evaporated fuel flows;
With
The purge passage and the bypass passage are connected apart from each other along the axial direction in the body and displace the valve body to displace the upstream passage with respect to the downstream passage through a communication portion provided in the valve body. The communication state of the side passage or the purge passage is switched.

  According to the present invention, in an internal combustion engine having an intake passage that supplies intake air to a plurality of cylinder chambers and a throttle valve that is provided in the intake passage and controls the flow rate of the intake air, an upstream side of the throttle valve An upstream passage is connected to the intake passage, and a downstream passage is connected to the intake passage downstream of the throttle valve, and the upstream passage and the downstream passage are connected to the switching valve. Connected. Further, a purge passage through which the evaporated fuel vapor flows is connected to the switching valve.

  And, for example, the downstream passage is connected via the communicating portion provided in the valve body by displacing the valve body of the switching valve along the axial direction based on the traveling speed of the vehicle, the rotational speed of the internal combustion engine, or the like. The communication state of the upstream side passage or the purge passage can be switched. Accordingly, since the supply of intake air to the plurality of intake passages and the supply of evaporated fuel can be controlled by a single switching valve, piping for supplying the evaporated fuel to each intake passage is provided separately. There is no need to simplify the piping configuration, and accordingly, the number of parts in the fuel vapor control apparatus can be reduced and the assembly efficiency can be improved.

  Further, since the evaporated fuel can be distributed to the intake passage at a desired timing under the switching action of the switching valve, the evaporated fuel can be reliably and efficiently distributed to the intake passage and burned in the cylinder chamber. Is possible.

  Furthermore, the communication part is preferably composed of an annular recess formed in the central part along the axial direction on the outer peripheral surface of the switching valve, and the purge passage and the downstream passage are communicated with each other via the recess.

  Further, the communication portion is formed of a groove portion extending along the axial direction on the outer peripheral surface of the switching valve and facing the opening portion of the downstream side passage, and the purge passage and the downstream side passage through the groove portion. It is good to communicate with.

  According to the present invention, the following effects can be obtained.

  That is, the downstream side passage in the bypass passage through the communicating portion provided in the valve body by displacing the valve body of the switching valve along the axial direction based on the traveling speed of the vehicle, the rotational speed of the internal combustion engine, etc. The communication state of the upstream side passage or the purge passage can be switched. As a result, it is possible to control the supply of intake air to a plurality of intake passages and the supply of evaporated fuel through the purge passages with a single switching valve, so that the evaporated fuel is supplied to each intake passage. There is no need to provide a separate pipe, the piping configuration can be simplified, the number of parts in the evaporated fuel control device can be reduced, and the assembly efficiency can be improved. Further, since the evaporated fuel can be distributed to the intake passage at a desired timing under the switching action of the switching valve, the evaporated fuel can be reliably and efficiently distributed to the intake passage and burned in the cylinder chamber. Can do.

1 is a schematic configuration diagram illustrating a configuration of an evaporated fuel control device according to an embodiment of the present invention and an internal combustion engine used in the evaporated fuel control device. 2A is a cross-sectional view showing a state in which the first passage portion and the second passage portion communicate with each other in the switching valve constituting the fuel vapor control apparatus of FIG. 1, and FIG. 2B is a valve body in the switching valve of FIG. 2A. FIG. 2C is a cross-sectional view showing the fully closed state in which the first and second passage portions and the purge pipe are closed by FIG. 2, and FIG. 2C is a state in which the valve body in FIG. 2B is lowered and the purge pipe and the second passage portion communicate with each other. FIG. It is sectional drawing which followed the III-III line of FIG. 2C. 4A is an overall cross-sectional view of a switching valve according to a modified example, FIG. 4B is an overall cross-sectional view showing a state where the valve body of FIG. 4A is lowered, and FIG. 4C is taken along line IVC-IVC in FIG. FIG.

  A preferred embodiment of an evaporative fuel control apparatus for an internal combustion engine according to the present invention will be described in detail below with reference to the accompanying drawings.

  In FIG. 1, reference numeral 10 indicates an evaporated fuel control device for an internal combustion engine according to an embodiment of the present invention.

  First, the internal combustion engine 12 to which the evaporated fuel control device 10 is mounted will be briefly described with reference to FIG. Examples of the vehicle on which the internal combustion engine 12 is mounted include an automobile and a motorcycle.

  The internal combustion engine 12 includes a main body 16 having a plurality of cylinder chambers 14 in which pistons (not shown) are accommodated, an intake manifold 18 connected to each of the cylinder chambers 14 for introducing intake air, and an interior of the intake manifold 18. And a throttle valve 20 that can control the flow rate of the intake air, and an injector 22 that is provided in the intake manifold 18 and injects fuel.

  The intake manifold 18 has a plurality of intake passages 24a to 24d through which intake air flows, and a throttle valve 20 for controlling the flow rate of the intake air is provided in each of the intake passages 24a to 24d provided in parallel. It can be opened and closed freely. An intake duct (not shown) is provided on the upstream side of the intake manifold 18, and outside air is introduced through the intake duct.

  The throttle valve 20 is, for example, a multiple throttle valve provided with a valve 27 corresponding to each intake passage 24a to 24d. The valve 27 is integrally connected via a shaft 26, and an intake manifold. The flow rate of the intake air is controlled by changing the passage cross-sectional area of the intake passages 24a to 24d by being rotated by a rotation drive source 28 (for example, a stepping motor) provided outside the motor 18.

  The injector 22 is provided downstream of the throttle valve 20 (in the direction of arrow A) in the intake manifold 18 and injects fuel (for example, gasoline) into the intake passages 24a to 24d based on a control signal from a control unit (not shown). The fuel and the intake air are mixed and supplied to the cylinder chamber 14 of the main body 16. The injectors 22 are respectively connected to the fuel tube 30 and inject fuel supplied through the inside of the fuel tube 30.

  The fuel tube 30 is connected to a fuel tank 34 in which fuel is stored via a fuel pipe 32, and the fuel is supplied by a fuel pump 36 provided in the fuel tank 34.

  The fuel tank 34 is connected to the canister 38 through the fuel pipe 32, and the evaporated fuel vaporized in the fuel tank 34 is adsorbed by the canister 38.

  Next, the evaporated fuel control apparatus 10 used for the internal combustion engine 12 described above will be described with reference to FIGS. The evaporative fuel control device 10 includes a bypass pipe (bypass passage) 40 that connects the upstream side and the downstream side in the intake passages 24 a to 24 d of the intake manifold 18, and a switching valve 42 that switches the communication state of the bypass pipe 40. A drive unit 44 that switches the switching valve 42 and a purge pipe (purge passage) 46 that is connected to the switching valve 42 and through which evaporated fuel desorbed from the canister 38 flows.

  The bypass pipe 40 is connected to the upstream side (in the direction of arrow B) of the throttle valve 20 in the intake passage 24b, and communicates with a first passage portion (upstream side passage) 48 that communicates with a communication chamber 52 of a switching valve 42 described later. The chamber 52 and the intake passages 24a to 24d of the intake manifold 18 include second passage portions (downstream passages) 50a to 50d respectively connected to the downstream side (arrow A direction) of the throttle valve 20. The first passage portion 48 is connected to one of the plurality of intake passages 24a to 24d, while four second passage portions 50a to 50d are provided corresponding to the number of intake passages 24a to 24d.

  In other words, the first passage portion 48 is an upstream passage connected to the upstream side (in the direction of arrow B) of the throttle valve 20 in the intake passages 24a to 24d, and the second passage portions 50a to 50d are the intake passages. 24a to 24d are downstream passages connected to the downstream side of the throttle valve 20 (in the direction of arrow A).

  The switching valve 42 includes a bottomed cylindrical body 54 in which a communication chamber 52 is formed, and a valve body 56 slidably provided along the communication chamber 52 of the body 54. A first passage portion 48 that constitutes the bypass pipe 40 is connected to a lower end portion in the direction (directions of arrows C and D) and communicates with the inside of the body 54. On the other hand, the upper end portion of the body 54 along the axial direction is closed by connecting the drive unit 44.

  For example, a stepping motor that is rotationally displaced based on a control signal from a control unit (not shown) is used as the drive unit 44, and a valve body 56 is screwed to a drive shaft 58 provided at the center thereof. . Then, when the drive shaft 58 rotates under the rotational action of the drive unit 44, the valve body 56 is displaced along the body 54 in the vertical direction (arrow C, D direction). The drive shaft 58 is made of, for example, a metal material.

  A plurality of second passage portions 50a to 50d are connected to the side surface of the body 54 below the first passage portion 48 (in the direction of arrow C), and communicate with the internal communication chamber 52, respectively. As shown in FIG. 3, the second passage portions 50 a to 50 d are disposed at equal intervals along the circumferential direction of the body 54.

  Further, a purge pipe 46 is connected to the side surface of the body 54 above the second passage portions 50 a to 50 d on the drive portion 44 side (arrow D direction), and communicates with the communication chamber 52 of the body 54. . The purge pipe 46 is provided so as to connect between the canister 38 and the switching valve 42, and the evaporated fuel desorbed from the canister 38 is supplied to the switching valve 42.

  The valve body 56 is formed in a columnar shape, and its outer peripheral surface abuts on the inner wall surface of the body 54 and is guided to be displaceable along the axial direction (arrow C, D direction). A drive shaft 58 to which the drive force of the drive unit 44 is transmitted is connected to the center of the unit, and the valve body 56 is urged in the vertical direction (arrow C, D direction) via the drive shaft 58.

  Further, on the outer peripheral surface of the valve body 56, an annular recess 60 that is recessed radially inward is formed at a substantially central portion along the axial direction, and a first land portion 62 provided on the upper portion of the annular recess 60 and And a second land portion 64 provided at a lower portion of the annular recess 60. In the valve body 56, a space formed between the annular recess 60 and the inner wall surface of the body 54 serves as a communication path through which intake air and evaporated fuel flow.

  Further, as shown in FIG. 3, a guide groove 66 is formed along the axial direction on the outer peripheral surface of the valve body 56. The guide groove 66 is fixed to the body 54 and protrudes to the inside. 68 is inserted. That is, the valve body 56 is restricted from being rotationally displaced with respect to the body 54 when the guide pin 68 is inserted into the guide groove 66, and can only be displaced along the axial direction. In other words, the guide pin 68 and the guide groove 66 function as rotational displacement restricting means for restricting the rotational displacement of the valve body 56.

  The evaporative fuel control apparatus 10 for the internal combustion engine 12 according to the embodiment of the present invention is basically configured as described above. Next, the operation and effects thereof will be described.

  First, immediately after starting the internal combustion engine 12, in a fast idle state in which the driver does not operate an accelerator pedal (not shown), a control signal from a control unit (not shown) is output to the switching valve 42, and FIG. As shown, the valve body 56 of the switching valve 42 is raised, and the second land portion 64 is disposed above the second passage portions 50a to 50d of the bypass piping 40, whereby the first passage of the bypass piping 40 is shown. The portion 48 and the second passage portions 50 a to 50 d communicate with each other through the communication chamber 52. On the other hand, since the opening of the purge pipe 46 is closed by the second land portion 64, the communication with the communication chamber 52 is blocked, and the evaporated gas is supplied into the communication chamber 52. Absent. In this idle state, the throttle valve 20 is in a state where communication between the upstream side and the downstream side of each of the intake passages 24a to 24d is blocked.

  As a result, the intake air supplied to the intake passages 24 a to 24 d of the intake manifold 18 flows to the switching valve 42 through the first passage portion 48, and the plurality of second passage portions 50 a to 50 d through the communication chamber 52. Circulate to Then, the intake air flows to the downstream side (in the direction of arrow A) of the throttle valve 20 in each of the intake passages 24 a to 24 d and is supplied into the cylinder chamber 14 of the main body 16.

  Next, in a warm-up state where the internal combustion engine 12 is heated, or in a normal state where the driver operates an accelerator pedal (not shown) to drive the vehicle at a constant speed, a control signal from a control unit (not shown) 2B, as shown in FIG. 2B, the valve body 56 of the switching valve 42 is slightly lowered from the state of FIG. 2A (in the direction of the arrow C), and the second land portion 64 is the second passage portion 50a. Since the annular recess 60 is disposed so as to face the purge pipe 46, it is introduced from the purge pipe 46. The evaporated fuel to be discharged does not flow to the first and second passage portions 48, 50a to 50d through the annular recess 60.

  Further, for example, when the internal combustion engine 12 is operating at a high speed or a high load in an acceleration state of the vehicle, a control signal from a control unit (not shown) is output to the switching valve 42, and as shown in FIG. 2B is further lowered slightly from the state of FIG. 2B (in the direction of arrow C), and the annular recess 60 is located at the position facing the second passage portions 50a to 50d of the bypass pipe 40 and the purge pipe 46. As a result, the purge pipe 46 and the second passage parts 50a to 50d communicate with each other via the communication chamber 52, and the evaporated fuel passes through the purge pipe 46, the inside of the switching valve 42, and the second passage parts 50a to 50d. It supplies to each intake passage 24a-24d. Then, the evaporated fuel is introduced into the cylinder chamber 14 of the main body 16 from the intake passages 24 a to 24 d and burned together with the fuel supplied from the injector 22.

  At this time, since the first passage portion 48 of the bypass pipe 40 is closed by the second land portion 64 of the valve body 56, the communication between the first passage portion 48 and the second passage portions 50a to 50d is blocked. ing.

  As described above, in the present embodiment, for example, a control signal based on the traveling speed of the vehicle, the rotational speed of the internal combustion engine 12, and the like is output from a control unit (not shown) to the switching valve 42 of the evaporated fuel control device 10. The communication state of the purge pipe 46 and the bypass pipe 40 can be switched by the single switching valve 42 by moving the valve body 56 back and forth in the vertical direction (arrow C, D direction). In other words, the supply of intake air to the intake passages 24a to 24d and the supply of evaporated fuel can be controlled by the single switching valve 42, respectively.

  As a result, it is not necessary to separately provide piping for supplying the evaporated fuel to the intake passages 24a to 24d, and the piping configuration can be simplified as compared with the evaporated fuel control device according to the prior art. Accordingly, it is possible to reduce the number of parts and improve the assembling efficiency in the evaporated fuel control device 10.

  This is particularly effective when a multiple throttle valve 20 having valves 27 corresponding to the plurality of intake passages 24a to 24d is used.

  Further, by switching the switching valve 42, the evaporated fuel can be circulated to the intake passages 24a to 24d at a desired timing, so that the evaporated fuel can be reliably and efficiently circulated to the intake passages 24a to 24d. It becomes possible to burn in the cylinder chamber 14.

  Further, the annular recess 60 is provided on the outer peripheral surface of the valve body 56, and the second passage portions 50a to 50d in the bypass pipe 40 and the purge pipe 46 are communicated with each other via the annular recess 60. It is avoided that the drive shaft 58 that is configured is directly exposed to the evaporated fuel, and deterioration of the drive shaft 58 due to the evaporated fuel can be suppressed. As a result, the durability of the drive unit 44 can be improved, and the drive unit 44 can be stably operated over a long period of time. In particular, in a shaft in which a screw is engraved on the outer peripheral surface such as the drive shaft 58, the deterioration can be effectively suppressed.

  On the other hand, as described above, the switching valve 42 has the annular recess 60 formed annularly on the outer peripheral surface of the valve body 56, but is not limited to such a configuration. For example, FIGS. Like the switching valve 100 shown in FIG. 4C, a valve body that has four grooves 104 a to 104 d on the outer peripheral surface that extend along the axial direction on the outer peripheral surface and are spaced at equal intervals along the circumferential direction. 102 may be used.

  The groove portions 104a to 104d are formed, for example, in a rectangular cross section, and are recessed by a predetermined depth from the outer peripheral surface of the valve body 102, and are directed downward (in the direction of arrow C) from the upper end portion of the valve body 102. It is extended.

  Further, the lengths of the groove portions 104a to 104d are located above (in the direction of the arrow D) with respect to the second passage portions 50a to 50d when the valve body 102 shown in FIG. When the valve body 102 shown in the figure is lowered, the lower end portion thereof is set so as to face the second passage portions 50a to 50d (see FIG. 4C).

  In the fast idle state of the internal combustion engine 12, as shown in FIG. 4A, the valve body 102 rises under the drive action of the drive portion 44, and the first passage portion 48 and the second passage portion constituting the bypass pipe 40. 50a to 50d communicate with each other through the communication chamber 52. As a result, the intake air supplied to the intake passages 24 a to 24 d of the intake manifold 18 flows to the downstream side of the throttle valve 20 through the bypass pipe 40 and is then supplied to the main body 16.

  At this time, the purge pipe 46 communicates with the purge communication chamber 106 provided above the valve body 102, and the evaporated fuel introduced into the purge communication chamber 106 is introduced into the grooves 104a to 104d.

  On the other hand, at the time of high speed or high load operation of the internal combustion engine 12, the valve body 102 descends from the state of FIG. 4A (in the direction of arrow C), and as shown in FIGS. 4B and 4C, the lower ends of the grooves 104a to 104d These are positions facing the openings of the second passage portions 50a to 50d. As a result, the evaporated fuel from the purge pipe 46 flows through the purge communication chamber 106 and the groove portions 104a to 104d to the second passage portions 50a to 50d and is supplied to the intake passages 24a to 24d. Then, the evaporated fuel is introduced into the cylinder chamber 14 of the main body 16 from the intake passages 24 a to 24 d and burned together with the fuel supplied from the injector 22.

  That is, by using the switching valve 100 having such a valve body 102, the grooves 104a to 104d can be formed simultaneously and easily when the valve body 102 is formed by molding using a mold or the like. It becomes possible.

  The evaporative fuel control apparatus for an internal combustion engine according to the present invention is not limited to the above-described embodiment, and can of course adopt various configurations without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 ... Evaporative fuel control apparatus 12 ... Internal combustion engine 16 ... Main-body part 18 ... Intake manifold 20 ... Throttle valve 22 ... Injector 24a-24d ... Intake passage 34 ... Fuel tank 38 ... Canister 40 ... Bypass piping 42, 100 ... Switching valve 44 ... Drive part 46 ... purge piping 48 ... first passage part 50a-50d ... second passage part 52 ... communication chamber 54 ... body 56, 102 ... valve body 58 ... drive shaft 60 ... annular recess 104a-104d ... groove

Claims (3)

Used in an internal combustion engine having an intake passage that supplies intake air to a plurality of cylinder chambers, and a throttle valve that is provided in the intake passage and controls the flow rate of the intake air. In the evaporative fuel control device that supplies the cylinder chamber,
A bypass passage comprising an upstream passage connected to the upstream side of the throttle valve in the intake passage, and a plurality of downstream passages connected to the downstream side of the throttle valve in the intake passage;
A body connected to the bypass passage; a valve body provided inside the body so as to be displaceable; and a drive unit that displaces the valve body along an axial direction. A switching valve capable of switching the communication state of the passage,
A purge passage connected to the switching valve and through which the evaporated fuel flows;
With
The purge passage and the bypass passage are connected apart from each other along the axial direction in the body and displace the valve body to displace the upstream passage with respect to the downstream passage through a communication portion provided in the valve body. An evaporative fuel control device for an internal combustion engine, wherein the communication state of the side passage or the purge passage is switched. The evaporative fuel control device according to claim 1,
The communication portion is formed of an annular recess formed in the central portion along the axial direction on the outer peripheral surface of the switching valve, and is provided so that the purge passage and the downstream passage can communicate with each other via the recess. An evaporative fuel control apparatus for an internal combustion engine characterized by the above. The evaporative fuel control device according to claim 1,
The communication portion includes a groove portion that extends along the axial direction on the outer peripheral surface of the switching valve and faces the opening portion of the downstream side passage, and the purge passage and the downstream side through the groove portion. An evaporative fuel control device for an internal combustion engine, characterized in that the side passage is provided so as to be able to communicate therewith.

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