JP6347252B2 - Evaporative fuel introduction device for engine - Google Patents

Description

  The present invention relates to an evaporative fuel introduction device for an engine, and more particularly to an evaporative fuel introduction device for introducing evaporative fuel generated in a fuel tank into an intake passage of an engine equipped with an air cleaner.

  Conventionally, evaporative fuel generated in a fuel tank of an automobile or the like equipped with an internal combustion engine (engine) is collected by a canister from the viewpoint of preventing air pollution, and the collected evaporative fuel is collected in an intake passage of the engine. It is introduced and burned in the combustion chamber.

  For example, Patent Document 1 discloses a technique for introducing evaporated fuel into an intake passage by using a negative pressure in an intake passage generated by throttle throttling during engine operation, and a compressor using a motor as a power source for evaporation. Technology to pressurize the fuel and introduce it into the intake passage, or return the air pressurized by the turbocharger to the intake side of the turbocharger and reduce the air flow of this pressurized air A technique is described in which a negative pressure is generated and evaporated fuel is introduced from the canister into the intake passage by this negative pressure.

JP 2007-332855 A

  However, all of the techniques described in Patent Document 1 described above introduce evaporated fuel into the intake passage on the downstream side of the air cleaner, and the introduction portion of the evaporated fuel is provided in the middle portion of the intake passage, where space constraints are large. Need to be newly provided.

  Therefore, it is conceivable to introduce the evaporated fuel into the air cleaner having sufficient space. However, in this case, it is conceivable that part of the evaporated fuel introduced into the air cleaner adheres to the air element of the air cleaner, leading to a decrease in performance of the air element and a shortened life.

  The present invention has been made to solve the above-described problems of the prior art, and can prevent the evaporated fuel from adhering to the air element when the evaporated fuel is introduced into the air cleaner. It is an object of the present invention to provide an evaporative fuel introduction apparatus. It is another object of the present invention to provide an evaporative fuel introduction device that can use an air element without deviation when evaporative fuel is introduced into an air cleaner.

  In order to achieve the above object, an evaporative fuel introduction device for an engine according to the present invention is an evaporative fuel introduction device for introducing evaporative fuel generated in a fuel tank into an intake passage of an engine equipped with an air cleaner, The air cleaner includes a box-shaped case in which an intake inlet and an intake outlet are formed, and an air element that divides a space in the case into an upstream space including the intake inlet and a downstream space including the intake outlet, An evaporative fuel passage that communicates between the tank and the air cleaner, an end portion on the air cleaner side of the evaporative fuel passage, a discharge portion that discharges the evaporative fuel supplied from the evaporative fuel passage to the downstream space of the air cleaner, and surrounds the discharge portion And has a tubular shape that extends from the discharge portion toward the vicinity of the intake port of the air cleaner, and evaporates the travel path of the evaporated fuel from the discharge portion to the intake port. A shielding member that shields from the element, and the shielding member communicates with the outlet opening that opens toward the intake outlet side at the end on the intake outlet side, and with the downstream space at the other end. And an inlet opening that is open.

  In the present invention configured as described above, the shielding member extends from the periphery of the discharge portion toward the vicinity of the intake outlet of the air cleaner and shields the moving path of the evaporated fuel from the discharge portion to the intake outlet from the air element. The evaporated fuel discharged from the discharge portion to the downstream space of the air cleaner can be introduced to the intake passage without adhering to the air element, thereby preventing the air element from degrading performance and shortening its life. Further, the shielding member has a tubular shape, and the entrance opening of the shielding member is opened so as to communicate with the downstream space, so that the case enters the downstream space from the air cleaner and passes through the entrance opening from the downstream space. Thus, it is possible to provide an air movement path from the exit opening to the intake outlet through the inside of the shielding member and through the inside of the shielding member. As a result, two air moving paths in the air cleaner, that is, a path that enters the upstream space from the intake inlet and passes through the air cleaner on the side relatively close to the intake outlet and flows to the downstream space, and an upstream side from the intake inlet It is possible to create a path that enters the space and passes through the air cleaner on the side relatively close to the discharge portion and flows to the downstream space. By creating two air movement paths in the case, the air elements can be used more uniformly.

  In the present invention, preferably, the shielding member forms a closed cross section in a plane substantially perpendicular to the direction from the discharge portion toward the air outlet of the air cleaner.

  In the present invention configured as described above, it is possible to prevent the evaporated fuel released from the discharge portion from scattering into the downstream space of the air cleaner, thereby reliably preventing the evaporated fuel from adhering to the air element. it can.

  In the present invention, preferably, the inlet opening is folded back toward the inside of the shielding member having a tubular shape.

  According to the present invention configured as described above, it is possible to suppress the evaporated fuel flowing into the shielding member from the discharge portion from being discharged from the inlet opening. In addition, by folding the inlet opening portion inward, it is possible to suppress the generation of airflow from the shielding member toward the downstream space.

  In the present invention, preferably, the shielding member is fixed to the upper surface of the case of the air cleaner.

  In the present invention configured as described above, the shielding member can be protected from the influence of vibrations generated by the engine, whereby the evaporated fuel discharged from the discharge portion to the downstream space of the air cleaner is supplied to the air element. The intake passage can be reliably introduced without being attached. Further, the air element may be clogged by using the air cleaner for a long period of time, and the negative pressure may be generated in the downstream space due to the clogging of the air element. When negative pressure is generated in the downstream space, the negative pressure acts on the case, so the case may be provided with reinforcing means such as ribs. However, as in the present invention, the shielding member is placed on the upper surface of the case. By fixing, the shielding member functions as a reinforcing member, and there is no need to separately provide reinforcing means on the upper surface of the case.

  In the present invention, preferably, the intake outlet of the case is formed of a tubular member that communicates with the downstream space and extends from the main body of the case, the shielding member extends into the tubular member, and the outlet opening is Opened in the tubular member, the ceiling portion of the shielding member facing the upper surface of the case has a notch formed continuously with the inlet opening and extending in the direction of the outlet opening. The notch extends to the vicinity of the end of the discharge portion.

  According to the present invention configured as described above, the assembling property of the shielding member is improved by forming a notch that extends to the vicinity of the end of the discharge portion and that is continuous with the inlet opening portion in the ceiling portion of the shielding member. be able to. That is, when the shielding member extends into the tubular member and when the shielding member is attached after the discharge portion is attached to the case, first, the shielding member is inclined with respect to the case. It is necessary to insert the outlet opening side of the tube member into the tubular member. And after inserting the exit opening part side of a shielding member in a tubular member, a shielding member is returned to a horizontal state and a shielding member is fixed to the upper surface of a case. Then, by forming a notch continuous with the entrance opening in the ceiling portion of the shielding member, the shielding member can be fixed to the case while preventing the ceiling portion of the shielding member from hitting the discharge portion.

  In the present invention, it is preferable that the cutout portion extends to the inlet opening side from the end of the discharge portion.

  According to the present invention configured as described above, the end of the discharge portion can be disposed closer to the outlet opening than the cutout portion. Thereby, the edge of the discharge portion can be surrounded by the shielding member, and the evaporated fuel released from the discharge portion can be reliably retained in the shielding member.

  In the present invention, it is preferable that a fin extending in the axial direction of the tubular member and standing downward from the upper surface is formed on the upper surface of the case, and the shielding member is fixed to the upper surface of the case. The shielding member is fixed to the case by fitting the notch into the fin and joining them together.

  According to the present invention configured as above, the outlet opening side of the shielding member is inserted into the tubular member with the shielding member inclined with respect to the case, and then assembled so that the shielding member is returned to the horizontal state. The attachment property at the time can be improved. That is, by forming a fin extending in the axial direction of the tubular member on the upper surface of the case, the notch and the fin are inserted when the shielding member is returned to the horizontal state after the outlet opening side of the shielding member is inserted into the tubular member. Can be fitted. This facilitates relative positioning of the shielding member with respect to the case. Moreover, the fin and the notch can be fitted relatively easily by forming the fin into a shape extending substantially parallel to the insertion direction of the shielding member.

  In the present invention, it is preferable to further include a pressurized air introduction passage for communicating the intake passage of the engine with the discharge portion.

  According to the present invention configured as described above, the evaporated fuel can be discharged from the discharge portion using the pressurized air in the intake passage of the engine. Thereby, evaporative fuel can be discharge | released from a discharge part, without providing pressurization means, such as a pump.

  In the present invention, it is preferable to further include a blow-by passage that supplies blow-by gas in the engine to the intake passage upstream of the pressurized air introduction passage.

  According to the present invention configured as described above, when the blow-by gas in the engine is supplied to the intake passage, the exhaust component contained in the blow-by gas is released into the air cleaner through the pressurized air introduction passage. Even if it did, it can prevent that the said exhaust component adheres to an air element with a shielding member.

  As described above, according to the evaporated fuel introducing device for an engine according to the present invention, it is possible to prevent the evaporated fuel from adhering to the air element while introducing the evaporated fuel into the air cleaner. Further, according to the present invention, when evaporating fuel is introduced into the air cleaner, the air element can be used without deviation.

1 is a system configuration diagram of an engine system to which an evaporated fuel introduction device according to an embodiment of the present invention is applied. It is a perspective view of the air cleaner by the embodiment of the present invention. It is the III-III arrow line view which shows the internal structure of the air cleaner shown in FIG. It is a top view of the shielding duct by the embodiment of the present invention. It is a bottom view of the shielding duct by the embodiment of the present invention. It is the front view which looked at the shielding duct by embodiment of this invention from the upstream. FIG. 5 is a cross-sectional perspective view of a main part of a portion surrounded by a region VII in FIG. 4.

  Hereinafter, an evaporative fuel introduction device for an engine according to an embodiment of the present invention will be described with reference to the accompanying drawings. First, an overall configuration of an engine system to which an evaporated fuel introduction device according to an embodiment of the present invention is applied will be described with reference to FIG. FIG. 1 is a system configuration diagram of an engine system to which an evaporated fuel introduction device according to an embodiment of the present invention is applied.

  In FIG. 1, reference numeral 1 denotes an evaporated fuel introduction device for an engine according to an embodiment of the present invention. As shown in FIG. 1, the engine system to which the evaporated fuel introducing device 1 is applied has an engine 2 and a fuel tank 4 that stores fuel supplied to the engine 2.

  The engine 2 is an internal combustion engine such as a gasoline engine or a diesel engine, and in particular is a gasoline engine in the present embodiment. The engine 2 includes an engine block 8 having a cylinder 6 that takes out power by burning a mixture of fuel and intake air, a piston 10 that reciprocates in the cylinder 6, and a reciprocating motion of the piston 10 is converted into a rotational motion. A crank 12, a crank chamber 14 for housing the crank 12, and a head cover 9 are provided. The engine 2 is connected to an intake passage 16 for introducing intake air into the cylinder 6 and an exhaust passage 18 for discharging exhaust generated in the cylinder 6 to the atmosphere. The engine 2 includes a turbocharger 24 including a turbine 20 and a compressor 22. The turbine 20 of the turbocharger 24 is provided in the exhaust passage 18, and the compressor 22 is provided in the intake passage 16. ing.

  In the intake passage 16 of the engine 2, an air cleaner 26 is provided on the upstream side of the compressor 22 to filter outside air drawn into the intake passage 16. An intercooler 28 is provided on the downstream side of the compressor 22 to cool the air that has been compressed by the compressor 22 and has reached a high temperature. Air that flows into the intake passage 16 from the outside is filtered by the air cleaner 26 and then compressed by the compressor 22. The air compressed by the compressor 22 is cooled by the intercooler 28 and is taken into the cylinder 6 of the engine 2.

  The engine block 8 is provided with a first blow-by passage 81 that communicates the crank chamber 14 with the intake passage 16 downstream of the intercooler. The head cover 9 has an internal space that communicates with the crank chamber 14 and an upstream side of the compressor 22. A second blow-by passage 91 communicating with the intake passage 16 is provided. When negative pressure is generated in the intake passage 16 on the downstream side of the intercooler 28, fresh air is taken into the engine 2 via the second blow-by passage 91, and blow-by gas is supplied via the first blow-by passage 81. By introducing it into the intake passage 16 on the downstream side of the intercooler 28, the engine 2 is ventilated. Further, when positive pressure is generated in the intake passage 16 on the downstream side of the intercooler 28, the blow-by gas in the engine 2 is supplied to the intake passage 16 on the upstream side of the compressor 22 through the second blow-by passage 91. It has a structure to be introduced. The first blow-by passage 81 is provided with a check valve 82 so that the pressurized air does not flow back into the crank chamber 14 when a positive pressure is generated in the intake passage 16 on the downstream side of the intercooler 28. ing. In addition, an injector 30 for injecting fuel into the cylinder 6 is attached to the engine block 8, and a fuel passage 32 for introducing the fuel sent from the fuel tank 4 to the injector 30 is connected to the injector 30. ing.

  A fuel passage 32 is connected to the fuel tank 4, and a fuel pump 34 that delivers fuel from the fuel tank 4 is provided. The fuel stored in the fuel tank 4 is delivered from the fuel tank 4 by the fuel pump 34, and introduced into the injector 30 of the engine 2 through the fuel passage 32.

  Inside the fuel tank 4, there is a liquid fuel 36 (gasoline in the present embodiment) and an evaporated fuel 38 in which the liquid fuel 36 is vaporized. In order to prevent the evaporated fuel 38 from being released into the atmosphere, a canister 40 that adsorbs the evaporated fuel 38 is provided. A first purge line 42 that connects the canister 40 and the fuel tank 4 is connected between the canister 40 and the fuel tank 4. The evaporated fuel 38 generated in the fuel tank 4 is a first purge line 42. The gas is guided to the canister 40 through the purge line 42 and is adsorbed by the canister 40.

  Further, a second purge line 44 that connects the intake passage 16 and the canister 40 is connected between the intake passage 16 and the canister 40 on the downstream side of the intercooler 28. The evaporated fuel 38 adsorbed by the canister 40 is separated from the canister 40 by the negative pressure generated in the intake passage 16 when the throttle is returned during the operation of the engine 2, and passes through the second purge line 44 to intake air of the engine 2. It is introduced into the passage 16 and burned in the cylinder 6 of the engine 2. A check valve 46 is provided in the second purge line 44. When no negative pressure is generated in the intake passage 16 on the downstream side of the intercooler 28, the check valve 46 prevents the backflow of the evaporated fuel 38 in the second purge line 44.

  In addition, a third purge line 48 (evaporated fuel passage) that connects the second purge line 44 and the air cleaner 26 is connected between the second purge line 44 and the air cleaner 26. That is, the third purge line 48 communicates with the fuel tank 4 via the first purge line 42, the canister 40 and the second purge line 44, and the second purge line 48 passes through the canister 40 and passes through the second purge line 42. Part or all of the evaporated fuel 38 flowing through the purge line 44 is supplied from the second purge line 44 to the air cleaner 26 through the third purge line 48. A check valve 50 is provided in the third purge line 48.

  Further, between the intake passage 16 and the air cleaner 26 on the downstream side of the intercooler 28, a pressurized air introduction passage 52 that connects the intake passage 16 and the inside of the air cleaner 26 is connected. Part of the pressurized air compressed by the compressor 22 and cooled by the intercooler 28 is introduced from the intake passage 16 through the pressurized air introduction passage 52 into the air cleaner 26.

  The air cleaner 26 is connected to the end of the pressurized air introduction passage 52 on the side of the air cleaner 26 and supplied from the third purge line 48 at the end of the third purge line 48 on the side of the air cleaner 26. In addition, an ejector 54 (discharge portion) for discharging the evaporated fuel 38 into the air cleaner 26 is provided.

  The ejector 54 includes a throttle portion formed in a tapered shape so that the cross-sectional area of the pressurized air flowing into the ejector 54 from the pressurized air introduction passage 52 decreases toward the downstream. An end of the third purge line 48 on the air cleaner 26 side is connected to the downstream side of the throttle portion of the ejector 54. When the pressurized air flowing into the ejector 54 from the pressurized air introduction passage 52 is ejected from the throttle portion at a high speed, a large negative pressure is generated around the ejected air (Venturi effect). The evaporated fuel 38 is sucked from the 3 purge line 48 and discharged into the air cleaner 26. When no negative pressure is generated in the ejector 54, the check valve 50 provided in the third purge line 48 prevents the backflow of the evaporated fuel 38 in the third purge line 48.

  Next, the evaporative fuel introducing device 1 for the engine 2 according to the embodiment of the present invention will be described in detail with reference to FIGS. 2 is a perspective view of the air cleaner 26 according to the embodiment of the present invention, FIG. 3 is a view taken along the line III-III showing the internal structure of the air cleaner 26 shown in FIG. 2, and FIG. 5 is a plan view of the shielding duct 72 according to the embodiment, FIG. 5 is a bottom view of the shielding duct 72 according to the embodiment of the present invention, and FIG. 6 is a view of the shielding duct 72 according to the embodiment of the present invention from the upstream side. It is a front view. The z-axis direction in FIGS. 2 to 6 represents the upward direction of the air cleaner 26 in the use state.

  First, as shown in FIG. 2, the air cleaner 26 has a box-shaped case 56. The case 56 has a structure that can be divided in the vertical direction, and includes a lower case 60 in which an intake port 58 is formed on a side surface, and an upper case 64 that is disposed above the lower case 60. . Further, an intake outlet 62 made of a tubular member extending from the upper case 64 is provided on the side surface of the upper case 64 so that the airflow in the case 56 can be discharged to the outside of the case through the intake outlet 62.

  Next, as shown in FIG. 3, the air element 66 is disposed substantially horizontally between the upper case 64 and the lower case 60 in the case 56 of the air cleaner 26. By the air element 66, the space in the case 56 is vertically divided into an upstream space 68 including the intake inlet 58 and a downstream space 70 including the intake outlet 62. As indicated by phantom lines in FIG. 3, the air that flows into the upstream space 68 from the intake inlet 58 of the lower case 60 passes upward through the air element 66 and flows into the downstream space 70, It flows out from the outlet 62 to the intake passage 16.

  In addition, as shown in FIG. 3, the ejector 54 is disposed above the air element 66 in the downstream space 70 of the air cleaner 26. Specifically, the ejector 54 is attached to a side surface opposite to the side surface of the upper case 64 in which the intake outlet 62 is formed, so that the evaporated fuel 38 and air are discharged from the ejector 54 toward the intake outlet 62. Is arranged.

  Further, in the downstream space 70 of the air cleaner 26 (that is, above the air element 66), there is provided a shielding duct 72 (shielding member) that covers the periphery of the ejector 54 and extends into the intake outlet 62 of the air cleaner 26. Yes. The shielding duct 72 shields the vaporized fuel 38 and the air movement path from the ejector 54 to the intake outlet 62 from the air element 66.

  As shown in FIGS. 3 to 7, the shielding duct 72 has a tubular shape that tapers from the ejector 54 side toward the intake outlet 62. The shield duct 72 has a rectangular closed cross section in a plane substantially perpendicular to the longitudinal direction (the direction in which the evaporated fuel 38 and air discharged from the ejector 54 flow toward the intake outlet 62 of the air cleaner 26). And the edge part by the side of the ejector 54 of the tubular shielding duct 72 is arrange | positioned adjacent to the case side surface to which the ejector 54 in the upper case 64 is attached. Further, the end of the shielding duct 72 on the intake outlet 62 side is disposed in the intake outlet 62 made of a tubular member. A predetermined gap S is provided between the end of the shielding duct 72 on the ejector 54 side and the side surface of the case to which the ejector 54 is attached. An entrance opening 72 a is formed at the end of the shielding duct 72 on the ejector 54 side so as to communicate the inside of the shielding duct 72 and the downstream space 70. Further, an outlet opening 72 b that opens in the intake outlet 62 is provided at the end of the shielding duct 72 on the intake outlet 62 side.

  The entrance opening 72 a of the shielding duct 72 opens toward the side of the shielding duct 72. The inlet opening 72 a communicates with the downstream space 70 via a gap S between the side surface of the shielding duct 72 and the inner surface of the upper case 64. As a result, an air flow can flow from the downstream space 70 through the gap S to the inlet opening 72a. The width of the inlet opening 72a is set to a width that allows the ejector 54 to be received. The width of the gap S is determined so that an airflow having a constant flow velocity can be generated from the downstream space 70 into the shielding duct 72.

  Furthermore, the ceiling portion of the shielding duct 72 is formed with a notch 72c that is formed continuously with the inlet opening 72a and extends toward the outlet opening. The notch 72 c has the same width as the inlet opening 72 a and has a shape that follows the shape of the ejector 54, and extends to the vicinity of the tip of the ejector 54 in the longitudinal direction of the shielding duct 72. Yes. More specifically, the notch 72c extends to the inlet opening 72a side from the tip 54a (see FIG. 4) of the ejector 54, and does not extend to the outlet opening 72b side from the tip 54a. Therefore, the front end 54 a of the ejector 54 is surrounded on all sides by the shielding duct 72 in a cross section orthogonal to the longitudinal direction of the shielding duct 72. As a result, even if the cutout portion 72 c is provided, the tip 54 a of the ejector 54 from which the evaporated fuel is discharged is surrounded by the shielding duct 72, and the evaporated fuel discharged from the ejector 54 is lower than the shielding duct 72. Can be prevented from dripping.

  Further, as shown in FIG. 7, the entrance opening 72a of the shielding duct 72 is folded back toward the inside of the tubular shielding duct 72, and along the side and lower sides of the entrance opening 72a, a flange is formed. A portion 72g is formed. By providing the flange portion 72g, it is possible to suppress the evaporated fuel that has flowed into the shielding duct 72 from the ejector 54 from being discharged from the inlet opening 72a, and toward the downstream space 70 from the shielding duct 72. Generation of airflow can be suppressed.

  As shown in FIGS. 4 and 5, the shielding duct 72 has a tapered shape such that the area of the cross section perpendicular to the longitudinal direction (flow path cross-sectional area) decreases from the periphery of the ejector 54 toward the intake outlet 62. Is formed. As shown in FIG. 3, the downstream end (the intake outlet 62 side) of the shielding duct 72 is formed smaller than the intake outlet 62 of the air cleaner 26 and is inserted into the intake outlet 62.

  As shown in FIG. 3, the bottom surface of the shielding duct 72 has an inclination that descends from the lower side of the ejector 54 toward the intake outlet 62, and the evaporated fuel 38 discharged from the ejector 54 is contained in the shielding duct 72. When the fuel liquefied by the engine 2 or the fuel liquefied while the engine 2 is stopped leaks into the shield duct 72 from the ejector 54, the liquefied fuel is introduced into the intake passage 16 without dripping into the air element 66. It has become so.

  As shown in FIGS. 4 to 6, a plurality (three in the present embodiment) of flanges 74 are provided at the upper end of the side surface of the shielding duct 72, and these flanges 74 are connected to the upper case 64 of the air cleaner 26. By attaching to the upper surface, the shielding duct 72 is fixed to the upper case 64 so that the upper surface of the ceiling portion of the shielding duct 72 faces the inner surface of the upper case 64. For example, when the upper case 64 and the shielding duct 72 of the air cleaner 26 are made of plastic, the flange 74 of the shielding duct 72 is attached to the upper surface of the upper case 64 of the air cleaner 26 by welding. The air element 66 may be clogged when the air cleaner 26 is used for a long period of time, and the negative pressure may be generated in the downstream space due to the clogging of the air element 66. And when a negative pressure generate | occur | produces in the downstream space 70, since the negative pressure acts on cases 60 and 64, reinforcement means, such as a rib, may be provided in a case. On the other hand, as in the present embodiment, by fixing the shielding duct 72 to the upper surface of the upper case 64, the shielding duct 72 functions as a reinforcing member for the upper case 64, and a reinforcing means is separately provided on the upper surface of the upper case 64. There is no need.

  More specifically, the shielding duct 72 includes a first flange 74a formed on the outlet opening 72b side of the shielding duct 72, and second and third flanges formed on the inlet opening 72a side of the shielding duct 72. 74b and 74c are provided. The first flange 74 a is provided with a notch 74 d that opens to the intake outlet 62 side and extends in the axial direction of the intake outlet 62. The second and third flanges 74 b and 74 c extend perpendicular to the side surface of the shielding duct 72, and have notches 74 e and 74 f that open toward the outside of the shielding flange 72, respectively.

  Further, as shown in FIG. 8, fins 64 a and 64 b are formed on the inner surface of the upper case 64 at positions corresponding to the notches 74 d, 74 e and 74 f when the shielding duct 72 is fixed at a fixed position of the upper case 64. , 64c are provided. The fins 64a, 64b, and 64c extend downward from the upper surface of the upper case 64 and have a width corresponding to the widths of the notches 74d, 74e, and 74f. The fin 64a corresponding to the notch 74d extends in parallel with the notch 74d, that is, in parallel with the intake outlet 62. When the shielding duct 72 is fixed to the upper case 64, all the fins 64a, 64b, 64c are fitted into the corresponding notch notches 74d, 74e, 74f, and the fins 64a, 64b, 64c are melted by ultrasonic welding or the like. And welded into the notches 74d, 74e, 74f.

  Next, a method for fixing the shielding duct 72 to the upper case 64 will be described in detail. When fixing the shielding duct 72 to the upper case 64, first, the shielding duct 72 is inclined so that the inlet opening 72a side of the shielding duct 72 faces downward. In this state, the end of the shielding duct 72 on the outlet opening 72 b side is inserted into the intake outlet 62. By inserting the shielding duct 72 into the intake outlet 62, when the shielding duct 72 is viewed from directly below, the entire ejector 54 can be visually recognized from the notch 72c. And after inserting the edge part by the side of the exit opening 72b of the shielding duct 72 in the intake outlet 62, it returns to a horizontal state, moving the shielding duct 72 to the entrance opening part 72a side. At this time, when the shielding duct 72 is returned to the horizontal state, the notches 74d, 74e, 74f and the fins 64a, 64b, 64c are fitted. This facilitates relative positioning of the shielding duct 72 with respect to the upper case 64. Further, when the shield duct 72 is returned to the horizontal state, the ejector 54 is accommodated inside the shield duct 72. Thus, by providing the notch 72 c, the shielding duct 72 can be fixed to the upper case 64 while preventing the ceiling portion of the shielding duct 72 from hitting the ejector 54.

  Next, further modifications of the embodiment of the present invention will be described. First, in the above-described embodiment, it has been described that the shielding duct 72 forms a closed cross section in a plane substantially orthogonal to the longitudinal direction thereof, but the shielding duct 72 causes the ejector 54 to the intake outlet 62 of the air cleaner 26. As long as the travel path of the evaporated fuel 38 can be shielded from the air element 66, the closed cross section is not necessarily formed. For example, a plate-shaped shielding member may be disposed above the air element 66 so as to extend from below the ejector 54 into the intake outlet 62.

  In the above-described embodiment, it has been described that the shielding duct 72 extends toward the intake outlet 62 of the air cleaner 26. However, the shielding duct 72 does not necessarily extend into the intake outlet 62 but extends to the vicinity of the intake outlet 62. May be provided.

  In the above-described embodiment, it has been described that the evaporated fuel 38 supplied from the third purge line 48 is discharged into the air cleaner 26 by the ejector 54 using the venturi effect. A device such as a pump may be used to discharge the evaporated fuel 38 supplied from the third purge line 48 into the air cleaner 26. Also in this case, similarly to the above-described embodiment, the shielding duct 72 that shields the moving path of the evaporated fuel 38 from the discharge portion of the evaporated fuel 38 inside the air cleaner 26 to the intake outlet 62 of the air cleaner 26 from the air element 66 is provided. Can be provided.

  Next, the operation and effect of the fuel vapor introduction device 1 for the engine 2 according to the above-described embodiment of the present invention and the modification of the embodiment of the present invention will be described.

  When supercharging is performed by the compressor 22 during operation of the engine 2, the pressurized air flows into the ejector 54 from the pressurized air introduction passage 52 due to the difference between the supercharging pressure and the atmospheric pressure. When the pressurized air that has flowed into the ejector 54 generates a negative pressure when it is ejected from the throttle portion of the ejector 54 at a high speed, the evaporated fuel 38 is sucked into the ejector 54 from the third purge line 48 by this negative pressure. The compressed air is discharged from the ejector 54 into the shielding duct 72. The evaporated fuel 38 and the air released into the shield duct 72 are introduced to the intake passage 16 along the shield duct 72 without scattering into the downstream space 70 of the air cleaner 26.

  The shield duct 72 extends from the periphery of the ejector 54 toward the vicinity of the intake outlet 62 of the air cleaner 26 and shields the moving path of the evaporated fuel 38 from the ejector 54 to the intake outlet 62 from the air element 66. The evaporated fuel 38 discharged into the downstream space 70 of the air cleaner 26 can be introduced to the intake passage 16 without adhering to the air element 66, thereby preventing performance deterioration and shortening of the life of the air element 66. Can do.

  Further, in this structure, as described above, the evaporated fuel is supplied using the pressurized air downstream of the intercooler from the pressurized air introduction passage 52, and the blowby gas is supplied to the intake passage 16 upstream of the compressor via the second blowby passage 91. The oil is introduced and the oil contained in the blow-by gas is also introduced, but this oil can also be introduced to the intake passage 16 without adhering to the air element 66.

  In particular, the shield duct 72 forms a closed cross section in a plane substantially perpendicular to the direction from the ejector 54 toward the air outlet 26 of the air cleaner 26, so that the evaporated fuel 38 and air flowing in the shield duct 72 are downstream of the air cleaner 26. It does not flow into the side space 70. Thus, the evaporated fuel 38 released from the ejector 54 can be prevented from scattering into the downstream space 70 of the air cleaner 26, and the evaporated fuel 38 can be reliably prevented from adhering to the air element 66.

  The air outlet 26 of the air cleaner 26 is disposed above the air element 66, the ejector 54 is disposed above the air element 66, and the bottom surface 72 a of the shielding duct 72 is disposed above the air element 66. Since the fuel gas 38 extends from the lower part of the air inlet 54 to the inside of the intake outlet 62 of the air cleaner 26, the evaporated fuel 38 discharged from the ejector 54 into the downstream space 70 of the air cleaner 26 is introduced into the intake passage 16 without adhering to the air element 66. In addition, the liquefied fuel flowing out from the ejector 54 can be prevented from dripping onto the air element 66.

  In particular, the bottom surface 72a of the shielding duct 72 has an inclination that descends from the lower side of the ejector 54 toward the intake outlet 62, so that the evaporated fuel 38 discharged from the ejector 54 liquefies in the shielding duct 72, When liquefied fuel leaks from the ejector 54 into the shielding duct 72 while the engine 2 is stopped, the liquefied fuel is introduced into the intake passage 16 without dripping into the air element 66. Can do.

  Further, since the shielding duct 72 is fixed to the upper case 64 of the air cleaner 26, the shielding duct 72 can be protected from the influence of vibration generated by the engine 2, and thereby the downstream side of the air cleaner 26 from the ejector 54. The evaporated fuel 38 released into the space 70 can be reliably introduced to the intake passage 16 without adhering to the air element 66.

  Further, by providing the entrance opening 72 a in the shielding duct 72, the air passes through the air cleaner 66 and enters the downstream space 70 in the case 56, and enters the shielding duct 72 from the downstream space 70 through the entrance opening 72 a. It is possible to provide an air movement path that enters from there and passes through the shielding duct 72 to the intake outlet 62 from the outlet opening 72b (see arrow R1 in FIG. 3). As a result, an air flow having a constant flow velocity is generated in the shielding duct 72, and the evaporated fuel released from the ejector 54 can easily flow toward the intake outlet 62.

  Further, when the shield duct 72 is inserted into the intake outlet 62, a gap is formed between the two, so that the shield duct 72 passes through the air cleaner 66 and enters the downstream space 70. It is possible to provide an air moving path that does not pass through to the intake outlet 62 (see arrow R2 in FIG. 3). Thereby, two air moving paths (R1 and R2) can be created in the air cleaner, and the air cleaner 66 can be used uniformly.

  Further, in this embodiment, the fuel vapor is discharged from the ejector 54 using the pressurized air from the pressurized air introduction passage 52. However, the pressurized air passage 52 is removed from the air cleaner 28 or the intake passage 16 for some reason. If it falls off, it is necessary to detect this.

  When the entrance opening 72a of the shielding duct 72 is not provided as in the prior art, negative pressure always acts in the vicinity of the exit opening 72b due to the flow of fresh air R2 shown in FIG. Therefore, even if the pressurized air introduction passage 52 falls off, the evaporated fuel continues to be released from the ejector 54 due to the negative pressure near the outlet opening 72b. If it does so, in the structure which is not provided with the entrance opening 72a like the past, it is difficult to detect the drop-off of the pressurized air passage 52 from the flow of the evaporated fuel. On the other hand, by providing the inlet opening 72a of the shielding duct 72 as in the present embodiment, a new fresh air flow R2 is formed, whereby a negative pressure always acts near the outlet opening 72b. There is no longer to do. If the pressurized air introduction passage 52 falls off, the evaporated fuel does not flow even though a positive pressure is generated on the downstream side of the intercooler 28. Accordingly, by detecting the flow of the evaporated fuel, it is possible to detect the drop of the pressurized air introduction passage 52.

DESCRIPTION OF SYMBOLS 1 Evaporated fuel introduction apparatus 2 Engine 4 Fuel tank 16 Intake passage 26 Air cleaner 38 Evaporated fuel 42 First purge line 44 Second purge line 48 Third purge line 52 Pressurized air introduction passage 54 Ejector 56 Case 58 Intake inlet 62 Intake outlet 64a 64b, 64c Fin 66 Air element 68 Upstream space 70 Downstream space 72 Shielding duct 72a Inlet opening 72b Outlet opening 74d, 74e, 74f Notch 74g Inlet opening flange

Claims (9)

An evaporative fuel introduction device that introduces evaporative fuel generated inside a fuel tank into an intake passage of an engine equipped with an air cleaner,
The air cleaner has a box-shaped case in which an intake inlet and an intake outlet are formed,
An air element that divides a space in the case into an upstream space including an intake inlet and a downstream space including an intake outlet;
An evaporative fuel passage communicating the fuel tank and the air cleaner;
A discharge portion for discharging the evaporated fuel supplied from the evaporated fuel passage to the downstream space of the air cleaner at the end of the evaporated fuel passage on the air cleaner side;
A shielding member that is disposed so as to surround the discharge portion, has a tubular shape extending from the discharge portion toward the vicinity of the intake outlet of the air cleaner, and shields the movement path of the evaporated fuel from the discharge portion to the intake outlet from the air element; Have
The shielding member has an outlet opening that opens toward the intake outlet side at an end on the intake outlet side, and an inlet opening that opens to communicate with the downstream space at the other end. An evaporative fuel introduction device, characterized in that   The evaporative fuel introduction device according to claim 1, wherein the shielding member forms a closed cross section in a plane substantially orthogonal to a direction from the discharge portion toward the intake outlet of the air cleaner.   The evaporative fuel introduction device according to claim 1, wherein the inlet opening is folded toward an inner side of a shielding member having a tubular shape.   The evaporative fuel introduction device according to any one of claims 1 to 3, wherein the shielding member is fixed to an upper surface of the case of the air cleaner. The intake outlet of the case is formed by a tubular member that communicates with the downstream space and extends from the main body of the case,
The shielding member extends into the tubular member, and the outlet opening opens in the tubular member;
The ceiling portion of the shielding member facing the upper surface of the case has a notch formed continuously with the inlet opening and extending in the direction of the outlet opening. The evaporative fuel introduction device according to claim 4, wherein the portion extends to the vicinity of the end of the discharge portion.   The evaporated fuel introduction device according to claim 5, wherein the notch extends to the inlet opening side from an end of the discharge part. The upper surface of the case is formed with fins extending in the axial direction of the tubular member and standing downward from the upper surface.
The shielding member is formed with a notch provided at a position where the fin can be fitted to the fin when fixed to the upper surface of the case.
The evaporated fuel introduction device according to claim 5 or 6, wherein the shielding member is fixed to the case by fitting the notch into the fin and joining the notches.   The evaporative fuel introduction device according to any one of claims 1 to 7, further comprising a pressurized air introduction passage that allows the intake passage of the engine and the discharge portion to communicate with each other.   The evaporative fuel introduction device according to claim 8, further comprising a blowby passage for supplying blowby gas in the engine to the intake passage upstream of the pressurized air introduction passage.

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