JP2005163690A - General purpose engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve merchantability and safety by paying attention to installation of a conduit for charging, in a general purpose engine having the canister for adsorbing evaporated fuel evaporated in a fuel tank and having an intake system continuous to an engine body to take the evaporated fuel desorbed from the canister therein. <P>SOLUTION: An evaporated fuel passage 78 communicating with the fuel tank 48 is formed between a tank cap 64 and the fuel tank 48 with a state where the tank cap is put on the fuel tank. The conduit 115 constitutes a part of the conduit 95A for charging which guides the evaporated fuel from the fuel tank 48 into the canister, and one end of the conduit 115 communicates with the evaporated fuel passage 78. The conduit 115 is disposed in the fuel tank 48 so as to pass through the inside of the fuel tank 48. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a general-purpose engine including a canister that adsorbs evaporated fuel evaporated in a fuel tank having a detachable tank cap, and evaporated fuel released from the canister is guided to an intake system connected to an engine body.

Such a general-purpose engine is already known from Patent Document 1, for example.
Japanese Utility Model Publication No. 47-10003

  By the way, in a general-purpose engine used for a work machine, a fuel tank is disposed so as to be exposed to the outside, and accordingly, a charging pipe for guiding evaporated fuel from the fuel tank is disposed outside. Because there is a high possibility of damage and deterioration during work and loading, it is necessary to pay sufficient attention to the piping of the charging pipe, and the enlargement of the general-purpose engine leads to the enlargement of the work equipment It is desirable to consider the piping path of the charging pipe so that it can contribute to the downsizing of the general-purpose engine. However, in the above-mentioned conventional one, the charging pipe for guiding the evaporated fuel from the fuel tank is connected to the upper center of the fuel tank, and the charging pipe is openly connected between the fuel tank and the canister. It is hard to say that sufficient attention has been paid to the handling of the pipelines.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a general-purpose engine capable of improving the merchantability and safety while paying attention to the arrangement of the charging conduit.

  In order to achieve the above object, the invention according to claim 1 includes a canister for adsorbing evaporated fuel evaporated in a fuel tank having a detachable tank cap, and the evaporated fuel separated from the canister is supplied to the engine body. In a general-purpose engine guided to a continuous intake system, an evaporated fuel passage leading to the inside of the fuel tank is formed between the tank cap and the fuel tank in a state where the tank cap is mounted, and the evaporated fuel from the fuel tank is A conduit that constitutes a part of a charging conduit that leads to the canister and passes through one end of the evaporated fuel passage is disposed in the fuel tank so as to pass through the fuel tank. .

  According to a second aspect of the invention, in addition to the configuration of the first aspect of the invention, an external communication path communicating with the outside is formed in the tank cap, and the pressure in the fuel tank is higher than the external pressure. A one-way valve is provided which opens when the temperature is low and allows the external communication passage to pass into the fuel tank.

  According to the first aspect of the present invention, since the pipeline constituting a part of the charging pipeline is disposed in the fuel tank, the portion of the charging pipeline that is exposed to the outside is reduced. It is possible to reduce the size of the engine as a whole and the work equipment, improve the mountability and appearance of general-purpose engines, and improve the product quality. Considering evaporative fuel leakage and pipe breakage To increase safety.

  According to the second aspect of the present invention, even if the ventilation resistance in the path from the charging line to the intake system through the canister increases due to the adsorbed fuel vapor or the retention of impurities in the canister, the one-way valve functions. Accordingly, it is possible to prevent the pressure in the fuel tank from becoming a negative pressure, and therefore it is possible to smoothly supply the fuel from the fuel tank even if the fuel level in the fuel tank decreases.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples of the present invention shown in the accompanying drawings.

  1 to 5 show a first embodiment of the present invention. FIG. 1 is a front view of the engine, FIG. 2 is a partially cutaway side view as seen from the direction of arrow 2 in FIG. 1, and FIG. 4 is a longitudinal sectional view of the fuel tank, FIG. 4 is an enlarged top view of FIG. 3, and FIG. 5 is an enlarged sectional view taken along line 5-5 of FIG.

  First, in FIG. 1 and FIG. 2, this general-purpose engine is an air-cooled single-cylinder engine used for, for example, a work machine, and the engine body 11 has a crankcase 12 and a cylinder axis C inclined upward. The cylinder block 13 is coupled to one side surface of the case 12 and the cylinder head 14 is joined to the head of the cylinder block 13. Many air cooling fins are provided on the outer surface of the cylinder block 13 and the cylinder head 14. 13a ..., 14a ... are provided. The crankcase 12 is installed on an engine bed of various working machines by an installation surface 12a on the lower surface of the crankcase 12, and a head cover 15 that covers a valve operating apparatus (not shown) is coupled to the cylinder head 14.

  The crankcase 12 includes a case main body 16 that is integrally formed with the cylinder block 13 and a side cover 17 that is coupled to an open end of the case main body 16. The crankcase 12 has a horizontal axis and has a crankcase. One end portion 18 a of the crankshaft 18 that is rotatably supported by 12 protrudes from the side cover 17. A case 20 of a recoil starter 19 that can be connected to the other end of the crankshaft 18 is attached to the case body 16 on the side opposite to the side cover 17.

  The engine intake system 21 includes a carburetor 22 disposed on the side of the recoil starter 19 and connected to the cylinder head 14 of the engine body 11, an intake pipe 23 connected to the carburetor 22 at a downstream end, And an air cleaner 24 connected to the upstream end of the intake pipe 23.

  A cleaner case 25 of the air cleaner 24 includes a cleaner case main body 26 formed in a bowl shape that opens downward, and a cover plate 27 that closes a lower open end of the cleaner case main body 26. A cylindrical first cleaner element 28 and a cylindrical second cleaner element 29 that concentrically surrounds the first cleaner element 28 are accommodated in 25. Thus, both axial ends of the first and second cleaner elements 28 and 29 are supported by a pair of disc-shaped holding plates 30 and 31, and one holding plate 31 is brought into contact with the lid plate 27. Thus, the cleaner elements 28 and 29 are accommodated in the cleaner case 25.

  The cleaner case 25 is partitioned by the two cleaner elements 28 and 29 into an outer unpurified chamber 32 and an inner purifier chamber 33, and the case main body 26 of the cleaner case 25 has an unpurified chamber 32. A suction pipe portion 26a communicating with the suction pipe portion 26a is integrally provided, and a suction pipe portion 34 for introducing outside air into the unpurified chamber 32 is connected to the suction pipe portion 26a.

  The outside air introduced into the non-purification chamber 32 through the suction pipe 34 and the suction pipe portion 26 a is purified by passing through the second cleaner element 29 and the first cleaner element 28, and is guided to the purification chamber 33. The purified air is guided to the carburetor 22 through the intake pipe 23.

  The intake pipe 23 extends downward from the air cleaner 24, and has a pipe body 35 that has a connecting pipe part 35 a that is open at the upper end and extends vertically and is connected to the vaporizer 22 at the lower part, and the pipe body 35. And a lid member 36 that contacts the lid plate 27 of the cleaner case 25 from below. The lid member 36 is integrally provided with an introduction pipe portion 36 a that penetrates the central portion of the lid plate 27 and the holding plate 31 and enters the purification chamber 33 from below.

  By the way, the pipe body 35 is engaged with the pipe body 35, the introduction pipe portion 36a of the lid member 36, the holding plate 30 and the enlarged diameter head portion 37a of the bolt 37 penetrating the upper closed end of the cleaner case main body 26 from below. A wing nut 38 that engages with the holding plate 30 from above is screwed into the bolt 37. Therefore, by tightening the wing nut 38, the first and second cleaner elements 28 and 29, the cover plate 27 of the cleaner case 25, and the intake pipe 23 are unitized. The cleaner case 25 is provided with a plurality of ribs 26b that contact the holding plate 30 from above at the upper closed end of the cleaner case main body 26, and the portion protruding upward from the upper closed end of the cleaner case main body 26 By screwing and tightening the wing nut 39 to the bolt 37, the assembly of the air cleaner 24 is completed and the air cleaner 24 and the intake pipe 23 are connected.

  The engine exhaust system 41 is supported by an exhaust pipe 42 connected to the cylinder head 14 of the engine body 11 on the side opposite to the carburetor 22 and a bracket 44 attached to the cylinder head 14 of the engine body 11. And an exhaust muffler 43 connected to the exhaust pipe 42. The exhaust muffler 43 is covered with a cover 45.

  That is, the intake system 21 and the exhaust system 41 are connected to the opposite side surfaces of the cylinder head 14 included in the engine body 11.

  A fuel tank 48 is disposed above the crankcase 12 in the engine body 11, and the fuel tank 48 is integrally formed with a support arm 49 provided integrally with the case body 16 of the crankcase 12 and the cylinder block 13. It is supported by the provided support arm 50.

  In FIG. 3, the fuel tank 48 includes a peripheral portion of an upper tank half 51 formed in a bowl shape opened downward and a peripheral portion of a lower tank half 52 formed in a bowl shape opened upward. The peripheral edge portion of the support cover 53 formed in a bowl shape so as to cover the lower tank half body 52 from below is formed on the peripheral edge portions of the upper and lower tank half bodies 51, 52. Combined.

  A head 54 a of a bolt 54 inserted into the support cover 53 and the support arm 49 is fixed to the inner surface of the support cover 53, and a weld nut 56 is fixed to the inner surface of the support cover 53. A nut 55 is screwed into the projecting portion, a bolt 57 inserted through the support arm 50 and the support cover 53 is screwed into the weld nut 56, and the nut 55 and the bolt 57 are tightened, whereby the support cover 53, that is, the fuel tank 48 is formed. Supported by the engine body 11.

  Referring also to FIG. 4, a seal support member 59 having a seal mounting hole 58 at the center is welded to the inner surface of the center portion of the upper tank half 51 in the fuel tank 48. An annular seal member 61 that forms an oil supply hole 60 on the inner periphery is attached. Further, at a position corresponding to the seal support member 59, a central portion of the upper tank half 51 is raised upward and connected in a ring shape, and a cylindrical shape extending downward and continuing to the inner periphery of the seal portion 62. The locking portion 63 is integrally formed.

  The oil supply hole 60 is closed by a tank cap 64 so that it can be opened and closed. The tank cap 64 is coupled to an insertion cylinder 65 that is removably inserted into the oil supply hole 60 and an upper end of the insertion cylinder 65. And a support cylinder 67 sandwiched between the insertion cylinder 65 and the operation member 66.

  The insertion cylinder 65 includes a bottomed small-diameter cylindrical portion 65b whose lower end is closed by an end wall 65a, a tapered portion 65c having a small-diameter end connected coaxially to the other end of the small-diameter cylindrical portion 65b, and a large diameter of the tapered portion 65c. A large-diameter cylindrical portion 65d that is coaxially connected to the radial end, a flange portion 65e that projects radially outward from the other end of the large-diameter cylindrical portion 65d, and the large-diameter cylindrical portion 65d coaxially from the outer periphery of the flange portion 65e A fitting cylinder portion 65 f extending toward the surrounding side is integrally provided, and the small-diameter cylindrical portion 65 b is inserted into the oil supply hole 60 while being in sliding contact with the seal member 61.

  The fitting cylinder portion 65f of the insertion cylinder 65 is fitted to the operation member 66 having a dish shape, and the opening edge of the operation member 66 is engaged with the tip of the fitting cylinder portion 65f. The operation member 66 is coupled to the upper end of the insertion tube 65 by caulking.

  The support cylinder 67 includes a first cylindrical portion 67a coaxially disposed in the small diameter cylindrical portion 65b of the insertion cylinder 65, and a first connecting rod projecting radially outward from an intermediate portion near the upper end of the first cylindrical portion 67a. A second cylindrical portion 67c that coaxially surrounds the first cylindrical portion 67a so as to be fitted to the portion 67b and the large-diameter cylindrical portion 65d of the insertion cylinder 65 and is connected to the outer periphery of the first connecting flange portion 67b. And a second connecting collar 67d projecting radially outward from an intermediate portion near the upper end of the second cylindrical section 67c, and an outer periphery of the second connecting collar 67d coaxially surrounding the second cylindrical section 67c. The upper end of the first to third cylindrical portions 67 a, 67 c, 67 e is in contact with the closed end of the operating member 66.

  Thus, an annular spacer 68 made of an elastic material is sandwiched between the second connecting collar 67d of the support tube 67 and the flange portion 65e of the insertion tube 65, and the opening edge of the operation member 66 is inserted into the insertion tube. The support tube 67 is clamped between the insertion tube 65 and the operation member 66 by caulking the fitting tube portion 65f of the roller 65 and coupling the operation member 66 to the upper end of the insertion tube 65. become.

  In the support cylinder 67, an engagement member 69 is slidably supported by the first cylindrical part 67a below the first connecting collar part 67b. The engaging member 69 includes a cylindrical boss portion 69a fitted to the first cylindrical portion 67a and a pair of engaging arm portions 69b extending from the boss portion 69a to both sides on a diameter line of the first cylindrical portion 67a. 69b, and a large-diameter cylindrical portion 65d of the insertion tube 66 is provided with a pair of slits 70, 70 penetrating the engaging arm portions 69b, 69b in the axial direction. It is done. That is, the engagement member 69 is prevented from turning around its axis by the slits 70 and 70 and the sliding range in the axial direction is restricted at both ends in the longitudinal direction of the slits 70 and 70. The cap 64 is attached and exerts a spring force between the end wall 65a of the insertion tube 65 and the engagement member 69 to urge the engagement member 69 toward the first connecting collar 67b of the support tube 67. Thus, the spring 71 is contracted.

  The distal end portions of both engaging arm portions 69b and 69b of the engaging member 69 protrude from the large-diameter cylindrical portion 65d of the insertion tube 65 so that the distal end portions of both engaging arm portions 69b and 69b can be inserted and removed. A pair of notches 72, 72 to be inserted is formed in the locking portion 63 of the fuel tank 48. Thus, the locking portion 63 is a process in which the tank cap 64 is rotated by a predetermined angle in one direction with the distal ends of the engaging arm portions 69b and 69b inserted in the notches 72 and 72. When the engagement member 69 is pushed in such a manner that the spring 71 is contracted and the tank cap 64 is rotated by the predetermined angle, both engagement arm portions 69b and 69b of the engagement member 69 elastically biased by the spring 71 are applied. Is formed so as to maintain the mounting state of the tank cap 64 to the fuel tank 48.

  A ring-shaped gasket 73 is attached to the outer periphery of the large-diameter cylindrical portion 65 d of the insertion cylinder 65 of the tank cap 64, and the gasket 73 is attached to the fuel tank 48 when the tank cap 64 is attached to the fuel tank 48. And the flange portion 65e of the insertion cylinder 65 in the tank cap 64.

  The upper end portion of the strap 74 is held on the end wall 65a of the insertion cylinder 65 in the tank cap 64, and the stopper 74 that prevents the oil supply port 60 from easily passing through is integrated with the lower end of the strap 74. Formed. Therefore, even if the tank cap 64 is removed from the fuel tank 48, the stopper 75 can be prevented from being caught by the seal support member 59 at the periphery of the fuel filler port 60 and the tank cap 64 falling off.

  An annular evaporative fuel passage 78 surrounding the tank cap 64 is formed between the seal portion 62 and the seal support member 59 of the fuel tank 48 and the tank cap 64 with the tank cap 64 mounted on the fuel tank 48. The The seal support member 59 is provided with a groove 79 between the inner surface of the upper tank half 51 in the fuel tank 48 to form a passage for allowing the evaporated fuel passage 78 to communicate with the fuel tank 48. That is, the evaporated fuel passage 78 communicates with the fuel tank 48.

  Further, an external communication path 80 communicating with the outside is formed between the operation member 66 and the support cylinder 67 of the tank cap 64. The external communication passage 80 includes a first annular passage portion 80 a formed between the flange portion 65 e of the insertion tube 65 and the operation member 66 outside the third cylindrical portion 67 e of the support tube 67, and a second of the support tube 67. And a second annular passage portion 80b formed between the third cylindrical portions 67c and 67e, a third annular passage portion 80c formed between the second and first cylindrical portions 67c and 67a of the support tube 67, and a support tube. And a central passage portion 80d formed in the first cylindrical portion 67a.

  The flange portion 65e of the insertion tube 65 is provided with an external communication hole 81 that allows the first annular passage portion 80a to communicate with the outside, and the first and second annular passage portions are formed at the upper end of the third cylindrical portion 67e of the support tube 67. A communication groove 82 for communicating 80b with each other is provided, and a communication groove 83 for communicating the second and third annular passage portions 80b and 80c with each other is provided at the upper end of the second cylindrical portion 67c of the support cylinder 67. A communication groove 84 is provided at the upper end of the first cylindrical portion 67a of the cylinder 67 to allow the third annular passage portion 80c to communicate with the central passage portion 80d.

  A partition wall 85 that defines the lower end of the central passage portion 80d in the external communication passage 80 divides the inside of the first cylindrical portion 67a vertically on the inner periphery of the portion of the support cylinder 67 near the lower end. And are provided integrally.

  The tank cap 64 is provided with a one-way valve 86 that opens when the pressure in the fuel tank 48 is lower than the external pressure and allows the external communication path 80 to communicate with the fuel tank 48. The valve 86 includes a valve hole 87 provided in a central portion of the partition wall 85 so as to be coaxially connected to a lower end of the central passage portion 80d in the external communication passage 80, and the partition wall 85 from the opposite side to the central passage portion 80d. And a leaf-shaped valve member 88 that can be seated at the center of the valve and close the valve hole 87.

  A closing member 89 is fitted to the lower end portion of the first cylindrical portion 67a. When the closing member 89 is fitted to the first cylindrical portion 67a, a part of the end wall 65a of the insertion tube 65 is cut. The support piece 90 formed by waking up is held by coming into contact with the closing member 89.

  A passage 91 communicating with the inside of the fuel tank 48 is provided in the central portion of the closing member 89 so as to apply the pressure in the fuel tank 48 to the valve member 88 from the side opposite to the partition wall 85. The distance between 89 and the partition 85 is set so as to allow the opening / closing operation of the valve member 88 accommodated between the closing member 89 and the partition 85.

  By the way, the evaporated fuel evaporated in the fuel tank 48 and guided to the evaporated fuel passage 78 is guided to the canister 96 by the charging conduit 95A, and the evaporated fuel separated from the canister 96 enters the intake pipe 23 in the intake system 21. The canister 96 is guided through a purge line 97 and is disposed on the side of the crankcase 12 in the engine body 11 and below the cylinder block 13 having the cylinder axis C inclined upward. The

  In FIG. 5, a casing 98 of a canister 96 has a bottomed cylindrical casing main body having an axis substantially parallel to the crankshaft 18 rotatably supported by the crankcase 12 of the engine body 11 and having an end wall 99a at one end. 99 and a lid member 100 which is welded to the casing main body 99 so as to close the other end opening portion, and is made of a synthetic resin.

  The intake system 21 and the exhaust system 41 are connected to the opposite side surfaces of the cylinder head 14 of the engine body 11. The casing 98 has an end wall 99 a of the casing main body 99 connected to the intake system 21. Arranged to face the side. The cylinder block 13 in the engine body 11 is provided with a heat insulating cover 101 that covers the cylinder block 13 from below so as to be interposed between the cylinder block 13 and the canister 96, and the casing 98 has a heat insulating cover. 101 is fixedly supported.

  The inner surface of the casing main body 99 and the end wall 99a are integrally provided with a partition wall 99b extending to the lid member 100 side with one end connected to the end wall 99a so as to divide the casing main body 99 vertically. On the other hand, a support member 103 is fitted and fixed to the other end portion of the casing main body 99 so as to form an intermediate chamber 111 between the cover member 100 and the support member 103. The other end of the casing main body 99 integrally includes a disc portion 103a having communication holes 102, 102... And a cylindrical portion 103b that extends toward the lid member 100 with one end connected to the outer periphery of the disc portion 103a. The other end of the cylindrical portion 103 b fitted to the portion is sandwiched between the lid member 100 and the casing main body 99.

  An upper adsorbent layer 104 formed by filling an adsorbent, for example, activated carbon, in the casing main body 99 above the partition wall 99b has a filter 106 interposed between the end wall 99a and a disk portion of the support member 103. The lower adsorbent layer 105 formed by filling an adsorbent, for example, activated carbon, into the casing main body 99 below the partition wall 99b is accommodated and held so as to interpose the filter 107 with the filter 103a. The filter 107 is interposed between the disk portion 103a of the member 103 and the filter 108 is interposed between and held by the end wall 99a.

  Above the partition wall 99b, the end wall 99a is integrally provided with an enormous portion 99c forming an introduction chamber 110 between the filter 106 and the filter 106 so as to bulge outwardly, and more than the partition wall 99b. A connecting tube portion 99d in which the filter 109 is fitted and accommodated is integrally provided on the end wall 99a so as to protrude outward, and the connecting tube portion 99d is provided between the end wall 99a and the filter 109. A cap 113 is fitted so as to form the discharge chamber 112. Moreover, the cap 113 is provided with an external communication hole 114 communicating with the discharge chamber 112 so as to open downward.

  The enlarging portion 99c is connected to a charging conduit 95A that guides the evaporated fuel from the fuel tank 48, and to a purge conduit 97 that guides the evaporated fuel that leaves the canister 96 to the intake pipe 23. The evaporated fuel evaporated in the fuel tank 48 when the engine is stopped is introduced into the introduction chamber 110 from the charging pipe 95A, and the filter 106, the upper adsorbent layer 104, the filter 107, the communication hole 102 of the support member 103, the intermediate chamber 111, Through the communication hole 102 of the support member 103, the filter 107, the lower adsorbent layer 105 and the filters 108, 109, the fuel flows into the discharge chamber 112 side, and the evaporated fuel is adsorbed by the upper and lower adsorbent layers 104, 105. Will be.

  On the other hand, when the engine is operated, the air introduced into the discharge chamber 112 from the external communication hole 114 is connected to the filters 109, 108, the lower adsorbent layer 105, the filter 107, the communication holes 102 of the support member 103, the intermediate chamber 111, and the support. Through the communication hole 102 of the member 103, the filter 107, the upper adsorbent layer 104, the filter 106, the introduction chamber 110, and the purge conduit 97, the air flows to the intake pipe 23 side. The evaporated fuel separated from the agent layer 104 is guided to the intake pipe 23 side along with the air.

  In such a canister 96, the inside of the casing 98 is partitioned up and down by a partition wall 99b, and the upper adsorbent layer 104 above the partition wall 99b and the lower adsorbent layer 105 below the partition wall 99b are evaporated fuel or evaporated. Since the air for entraining the fuel flows sequentially, the adsorption length can be increased while the casing 98 is made compact to contribute to the improvement of the adsorption efficiency.

  The charging pipe 95 </ b> A is formed between the tank cap 64 and the fuel tank 48 and passes through one end of the vaporized fuel passage 78 communicating with the fuel tank 48, and a pipe connecting the pipe 115 and the canister 96. The both pipe lines 115 and 116 are rubber hoses, for example.

  The seal support member 59 in the fuel tank 48 includes an intermediate portion of a connecting pipe 117 that vertically passes through the seal support member 59 on the side opposite to the canister 96 with respect to the axis of the tank cap 64. The upper end of the pipe line 115 is connected to the lower end of the connection pipe 117. Further, an intermediate portion of a connecting pipe 118 extending vertically and penetrating liquid-tightly through the bottom of the lower tank half 52 is attached to the bottom of the lower tank half 52 in the fuel tank 48, and the lower end of the pipe 115 is connected. One end of a pipe line 116 connected to the upper end of the pipe 118 and penetrating the support cover 53 is connected to the lower end of the connection pipe 118.

  That is, the conduit 115 constituting a part of the charging conduit 95A passes through the fuel tank 48 so as to communicate with the evaporated fuel passage 78 on the side opposite to the canister 96 with respect to the axis of the tank cap 64. It will be arranged in the inside.

  On the other hand, the enormous portion 99c in the canister canister 96 is provided with a pair of connecting pipe portions 119, 120 in parallel, and the other end of the pipe line 116 is connected to one connecting pipe portion 119. One end of a purge pipe 97 is connected to the other connection pipe 120, and the other end of the purge pipe 97 is connected to a connection pipe 35b provided integrally with the pipe body 35 of the intake pipe 23 in the intake system 21. Is done.

  In FIG. 3 again, a filter case 93 to which a filter 92 for filtering the fuel oil in the fuel tank 48 is attached is attached to the bottom of the lower tank half 51 in the fuel tank 48. The fuel oil hose 94 for guiding the fuel oil to the vaporizer 22 is connected.

  Next, the operation of the first embodiment will be described. The engine body 11 includes a crankcase 12 and a cylinder block 13 having a cylinder axis C inclined upward and coupled to the crankcase 12. A canister 96 that adsorbs the evaporated fuel evaporated in the fuel tank 48 is disposed on the side of the crankcase 12 and below the cylinder block 13.

  That is, since the cylinder axis C is inclined upward, a vacant space is generated below the cylinder block 13, and the canister 96 is disposed in such a vacant space, thereby increasing the size of the general-purpose engine as a whole. The canister 96 can be disposed while avoiding the above-mentioned problem. Moreover, even if the capacity of the canister 96 is slightly increased, the general-purpose engine does not increase in size, and the canister 96 is adsorbed while avoiding the increase in size of the general-purpose engine as a whole. Can increase the sex.

  The engine body 11 also includes a cylinder head 14 coupled to the head of the cylinder block 13 so that the intake system 21 and the exhaust system 41 are connected to opposite side surfaces. Since the charging conduit 95A for guiding the evaporated fuel and the purge conduit 97 for guiding the evaporated fuel separated from the canister 96 are connected to the portion of the casing 98 of the canister 96 facing the intake system 21 side, The charging pipe 95A and the purging pipe 97 are connected to the casing 98 of the canister 96 on the intake side where the influence of exhaust heat from the engine body 11 is small, so that the evaporated fuel can be adsorbed and separated by the canister 96. It is possible to prevent an adverse effect due to exhaust heat and improve the efficiency of the canister 96.

  Further, an evaporated fuel passage 78 communicating with the inside of the fuel tank 48 is formed between the fuel tank 48 and the tank cap 64 attached to the fuel tank 48, and the evaporated fuel from the fuel tank 48 is supplied to the canister 96. A charging line 115 that constitutes a part of the charging line 95A leading to the vaporized fuel passage 78 and passes through one end of the evaporated fuel passage 78 is disposed in the fuel tank 48 so as to pass through the fuel tank 48. The portion exposed to the outside of the pipe line 95A can be reduced to reduce the size of the general-purpose engine as a whole, and thus the work machine, and improve the mountability and appearance of the general-purpose engine to improve the merchantability. It is possible, and safety can be improved in consideration of leakage of evaporated fuel, breakage of pipelines, and the like.

  Moreover, the pipe 115 constituting a part of the charging pipe 95A communicates with the evaporated fuel passage 78 on the side opposite to the canister 96 with respect to the axis of the tank cap 64. When the fuel tank 48 tilts with the canister 96 side up, the fuel oil may flow into the pipe 115. Since the fuel oil is in a relatively upper position, the inflow of the fuel oil to the canister 96 is suppressed, so that the permanent inflow of the fuel oil to the canister 96 is prevented even if the fuel tank 48 is tilted. Become.

  Further, an external communication path 80 communicating with the outside is formed in the tank cap 64, and is opened when the pressure in the fuel tank 48 is lower than the external pressure to allow the external communication path 80 to communicate with the fuel tank 48. Since the directional valve 86 is provided, even if the ventilation resistance in the path from the charging pipe 95A to the intake system 21 via the canister 96 increases due to the adsorbed fuel vapor or the retention of impurities in the canister 96, the direction valve 86 The operation of the valve 86 can prevent the pressure in the fuel tank 48 from becoming negative. Therefore, even if the fuel level in the fuel tank 48 decreases, the fuel supply from the fuel tank 48 can be smoothly performed. Can be done.

  6 and 7 show a second embodiment of the present invention. FIG. 6 is an upper longitudinal sectional view of the fuel tank, and FIG. 7 is a sectional view taken along line 7-7 of FIG.

  A part of the charging pipe 95B for guiding the evaporated fuel evaporated in the fuel tank 48 to the canister 96 passes through the fuel tank 48 and the pipe 115, and the pipe 115 And a pipe 121 made of synthetic resin connected to the upper end.

  The pipe 121 has a connecting pipe part 121a attached to the seal support member 59 in the fuel tank 48 on the side opposite to the canister 96 (see the first embodiment) with respect to the axis of the tank cap 64, and is integrated with the connecting pipe part 121a. This is composed of an extension cylinder portion 121b that is continuously arranged in the evaporated fuel passage 78.

  The connection pipe part 121a is attached to the seal support member 59 so that the lower end of the connection pipe part 121a protrudes downward from the seal support member 59, and the upper end of the pipe line 115 is connected to the lower end of the connection pipe part 121a.

  In addition, the extension cylinder part 121b whose one end is integrally connected to the upper end of the connection pipe part 121a has an opening at the other end reaching the vicinity of the connection pipe part 121a so as to extend substantially in the annular evaporated fuel passage 78 over the entire circumference. It is bent into an arc shape to be arranged.

  A support member 122 that holds the extended cylindrical portion 121b of the conduit 21 is fixed to the inner surface of the seal support member 59. The support member 122 is fitted and fixed to the inner surface of the seal support member 59. A tube portion 122a, a support flange portion 122b projecting radially inward from the upper end of the support tube portion 122a, and an inner periphery regulating tube portion 122c rising upward from the inner periphery of the support flange portion 122b. The extension cylinder part 121b of the path 121 is placed and supported on the support collar part 122b while the inner circumference side of the arcuately arranged shape is regulated by the inner circumference formation cylinder part 122c.

  Further, the support member 122 is provided with a pair of notches 123 and 123 formed by cutting out a part of the support flange 122b and the inner circumference regulating cylinder portion 122c so as to be positioned on one diameter line. A rising part at one end of the extension cylinder part 121b from the connection pipe part 121a is arranged at one of the notches 123, 123.

  According to the second embodiment, when the fuel tank 48 tilts with the canister 96 side as the lower side, the other end opening of the extension cylinder 121b is in the upper position, so that the inflow of fuel oil into the pipe 121 is avoided, Further, when the fuel tank 48 is inclined with the canister 96 side as the upper side, the fuel pipe may flow into the other end opening of the extension cylinder part 121b, but the extension cylinder part 121b is bent in an arc shape. The fuel oil does not flow from 121 to the pipe line 115. Therefore, the fuel oil can be prevented from flowing into the canister 96 even if the fuel tank 48 is inclined.

  FIG. 8 shows a third embodiment of the present invention, and parts corresponding to the first and second embodiments are given the same reference numerals.

  A seal support member 59 ′ having a seal mounting hole 58 at the center is welded to the inner surface of the center portion of the upper tank half 51 in the fuel tank 48 ′. An annular seal member 61 is attached. Further, at a position corresponding to the seal support member 59 ′, a seal portion 62 bulging upward and continuing in an annular shape at the center portion of the upper tank half 51, and a cylinder extending downward and continuing to the inner periphery of the seal portion 62. And the like locking part 63 are integrally formed.

  A filter unit 124 is inserted into the upper portion of the fuel tank 48 ′ so that the upper ends thereof are engaged with the connecting portions of the seal portion 62 and the locking portion 63. A casing 125 of the filter unit 124 is inserted into the oil supply hole 60 while elastically contacting the seal member 61 and a filter support cylinder portion 125a formed in a bottomed cylindrical shape with an open upper end. A seal cylinder part 125b connected to the upper end of the filter support cylinder part 125a; a support cylinder part 125c extending upward from the upper end of the seal cylinder part 125b and inserted into the locking part 63; and an upper end of the support cylinder part 125c An engagement flange 125d extending outward in the radial direction is integrally formed of synthetic resin, and the engagement flange 125d is engaged with the connecting portion of the seal portion 62 and the locking portion 63 from above. Is done.

  The filter support cylinder portion 125a of the casing 125 is provided with a plurality of openings 126... From the side surface to the bottom surface, and a mesh-like filter 127 disposed in the openings 126. It is supported by the cylinder part 125a.

  The tank cap 130 includes an insertion cylinder 131 that is removably inserted into the upper portion of the casing 125 of the filter unit 124, a dish-shaped operation member 132 that is coupled to the upper end of the insertion cylinder 131, A support cylinder 133 inserted and fixed in the upper part, a pressing member 134 sandwiched between the support cylinder 133 and the operation member 132, a seal support piece 135 fixed to the lower end of the insertion cylinder 131, and the seal support piece 135 And a ring-shaped seal member 136 that is inserted and detachably inserted while elastically contacting the seal cylinder portion 125b of the casing 125 of the filter unit 124.

  The seal support piece 135 includes a bottomed cylindrical portion 135a formed in a bottomed cylindrical shape whose upper end is closed, and a mounting protrusion 135b formed in a substantially L-shaped longitudinal section and projecting from the outer surface of the bottomed cylindrical portion 135a. And a communication hole 137 is provided at the lower closed end of the bottomed cylindrical portion 135a. Thus, the seal member 136 is mounted on the seal support piece 135 so as to surround the bottomed cylindrical portion 135a while the mounting protrusion 135b is biting into the inner periphery.

  The insertion tube 131 is connected to the bottomed cylindrical portion 135a of the seal support piece 135 from above and is connected by caulking, and is connected to the upper end of the caulking coupling portion 131a at a substantially right angle. A circular and flat receiving step portion 131b that faces, a small-diameter cylindrical portion 131c that rises slightly upward from the outer periphery of the receiving step portion 131b, a tapered portion 131d in which a small-diameter end is coaxially connected to the upper end of the small-diameter cylindrical portion 131b, A large-diameter cylindrical portion 131e coaxially connected to the large-diameter end of the tapered portion 131d, a flange portion 131f projecting radially outward from the other end of the large-diameter cylindrical portion 131e, and the large-diameter from the outer periphery of the flange portion 131f A fitting tube portion 131g extending to the side surrounding the cylindrical portion 131e coaxially is integrally provided.

  The fitting cylinder 131g of the insertion cylinder 131 is fitted to the operation member 132 having a dish shape, and the opening edge of the operation member 132 is engaged with the tip of the fitting cylinder 131g. The operation member 132 is coupled to the upper end of the insertion tube 131 by caulking.

  The support cylinder 133 includes a first cylindrical portion 133 a that is coaxially disposed in the insertion cylinder 131, a connecting collar portion 133 b that protrudes radially outward from the upper end of the first cylindrical section 133 a, and a large size of the insertion cylinder 131. The second cylindrical portion 133c connected to the outer periphery of the connecting flange portion 133b so as to be fitted to the diameter cylindrical portion 131e and the flange portion 133d projecting radially outward from the upper end of the second cylindrical portion 133c are integrated. Prepare for.

  The holding member 134 is integrally formed with a bottomed cylindrical portion 134a fitted from above to the second cylindrical portion 133c of the support cylinder 133 and a flange portion 134b projecting radially outward from the upper end of the bottomed cylindrical portion 134a. To prepare for.

  Thus, the pressing member 134 is sandwiched between the support cylinder 133 and the operation member 132 such that the flange part 134b is disposed between the flange part 133d of the support cylinder 133 and the operation member 132. The opening edge of the operation member 132 is engaged with the fitting cylinder 131g of the insertion cylinder 131 with an annular spacer 138 made of an elastic material interposed between the flange 133d of the insertion cylinder 131 and the flange 131f of the insertion cylinder 131. By caulking in this manner, the upper end of the insertion tube 131 is coupled to the operation member 132, and the spacer 138, the upper end of the support tube 133 and the pressing member 134 are sandwiched between the operation member 132 and the support tube 133. Become.

  An engagement member 139 is supported by the tank cap 130 so as to be slidable up and down. The engagement member 139 includes a ring plate 139a surrounding the first cylindrical portion 133a of the support cylinder 133, and a ring plate portion 139a. A pair of engaging arm portions 139b and 139b extending from the ring plate portion 139a on both sides on one diameter line are integrally provided, and the large-diameter cylindrical portion 131e of the insertion tube 132 and the support of the filter unit 124 in the casing 125 are provided. A pair of slits 140, 140; 141, 141 that penetrate both the engaging arm portions 139b, 139b are provided in the cylindrical portion 125c and the engaging flange portion 125d so as to extend in the axial direction. That is, the engaging member 139 is prevented from rotating around its axis by the slits 140, 141, and the axial sliding range is restricted at both longitudinal ends of the slits 140, 141, etc. The engagement member 139 is connected to the tank cap 130 between the receiving step portion 131b of the insertion tube 131 and the ring plate portion 139a of the engagement member 139. The spring 142 is contracted so as to exert a spring force biased toward the 133b side.

  The distal ends of both engaging arm portions 139b, 139b of the engaging member 139 protrude from the support cylinder portion 125c of the casing 125 of the filter unit 124, and the distal ends of the engaging arm portions 139b, 139b are inserted and removed. A pair of notches 72, 72 that can be inserted is formed in the locking portion 63 of the fuel tank 48 '. Thus, the locking portion 63 is a process in which the tank cap 130 is rotated by a predetermined angle in one direction with the distal ends of the engaging arm portions 139b and 139b inserted into the notches 72 and 72, respectively. When the engagement member 139 is pushed in such a manner that the spring 142 is contracted and the tank cap 130 is rotated by the predetermined angle, both engagement arm portions 139b and 139b of the engagement member 139 elastically biased by the spring 142 are used. Is formed so as to maintain the mounting state of the tank cap 130 on the fuel tank 48 '.

  A ring-shaped gasket 73 is attached to the outer periphery of the large-diameter cylindrical portion 131e of the insertion tube 131 of the tank cap 130. This gasket 73 is a fuel tank when the tank cap 130 is attached to the fuel tank 48 '. It is sandwiched between the seal portion 62 of 48 'and the flange portion 131f of the insertion tube 131 in the tank cap 130.

  With the tank cap 130 mounted on the fuel tank 48 ′, an evaporated fuel passage 143 is formed between the seal portion 62 and the seal support member 59 ′ of the fuel tank 48 ′ and the support cylinder 133 of the tank cap 130, The evaporated fuel passage 143 communicates with the fuel tank 48 ′ via a communication hole 137 provided in the seal support piece 135 and filters 127.

  Further, an external communication path 144 communicating with the outside is formed between the operation member 132 of the tank cap 130 and the support cylinder 133 and the pressing member 134. The external communication path 144 includes an annular path 144a formed between the flange 131f, 133d, and 134b of the insertion cylinder 131, the support cylinder 133, and the pressing member 134 and the operation member 132 outside the spacer 138, and a pressing member. 134 and a passage portion 144b formed between the operation members 132 and a central passage portion 144c formed in the first cylindrical portion 133a of the support tube 133.

  The flange portion 131f of the insertion tube 131 is provided with an external communication hole 145 that allows the annular passage portion 144a to communicate with the outside, and the annular passage portion 144a and the passage portion 144b communicate with each other on the outer edge of the flange portion 134b of the pressing member 134. A communication groove 146 is provided, and a communication hole 147 is provided at the closed end of the bottomed cylindrical portion 134a of the pressing member 134 to allow the passage portion 144b and the central passage portion 144c to communicate with each other.

  A partition wall 148 that defines the lower end of the central passage portion 144c in the external communication passage 144 is vertically divided in the first cylindrical portion 133a of the support cylinder 133 so as to divide the first cylindrical portion 133a vertically. And are provided integrally.

  Also, a one-way valve 150 that opens when the pressure in the fuel tank 48 ′ is lower than the external pressure and allows the external communication path 144 to communicate with the fuel tank 48 ′ is provided in the tank cap 130. The one-way valve 150 includes a valve hole 151 provided in the central portion of the partition wall 148 so as to be coaxially connected to a lower end of the central passage portion 144c in the external communication passage 144, and the opposite side of the central passage portion 144c from the opposite side. And a leaf-like valve member 152 that can be seated at the center of the partition wall 148 and close the valve hole 151.

  A closing member 153 is fitted and fixed to the lower end portion of the first cylindrical portion 133a, and a passage 154 leading to the evaporated fuel passage 143 is formed at the central portion of the closing member 153, that is, the pressure in the evaporated fuel passage 143, that is, The pressure in the fuel tank 48 ′ is provided so as to act on the valve member 152 from the side opposite to the partition wall 148, and the interval between the closing member 153 and the partition wall 148 is accommodated between the closing member 153 and the partition wall 148. The opening / closing operation of the valve member 152 is set to be permitted.

  By the way, the evaporated fuel evaporated in the fuel tank 48 'and guided to the evaporated fuel passage 143 is guided to the canister 96 (see the first embodiment) by the charging conduit 95C. A part of the seal 115 in the casing 125 of the filter unit 124 is configured so that the upper end of the pipe line 115 that passes through the fuel tank 48 and is disposed in the fuel tank 48 communicates with the evaporated fuel passage 143. It is connected to the lower end of the connecting pipe part 125e provided integrally with 125b.

  According to the third embodiment, the same effect as that of the first embodiment can be obtained.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. It is.

It is a front view of the engine in 1st Example. It is a partially cutaway side view seen from the direction of arrow 2 in FIG. It is a longitudinal cross-sectional view of a fuel tank. FIG. 4 is an enlarged view of the upper part of FIG. 3. FIG. 5 is an enlarged sectional view taken along line 5-5 of FIG. It is an upper part longitudinal cross-sectional view of the fuel tank of 2nd Example. FIG. 7 is a cross-sectional view taken along line 7-7 in FIG. 6. It is an upper part longitudinal cross-sectional view of the fuel tank of 3rd Example.

Explanation of symbols

11 ... Engine body 21 ... Intake system 48, 48 '... Fuel tank 64, 130 ... Tank cap 78, 143 ... Evaporative fuel passage 80, 144 ... External communication passage 86, 150 ... One-way valve 96 ... Canisters 95A, 95B, 95C ... Charge pipe 115 ... Pipe

Claims (2)

  A fuel tank (48, 48 ') having a detachable tank cap (64, 130) is provided with a canister (96) for adsorbing the evaporated fuel evaporated, and the evaporated fuel released from the canister (96) is removed from the engine body. In the general-purpose engine guided to the intake system (21) connected to (11), between the tank cap (64, 130) and the fuel tank (48, 48 ') with the tank cap (64, 130) mounted. Are formed with evaporative fuel passages (78, 143) communicating with the inside of the fuel tanks (48, 48 '), and charging tubes for guiding the evaporative fuel from the fuel tanks (48, 48') to the canister (96). A pipe line (115) constituting a part of the path (95A, 95B, 95C) and passing through one end of the vaporized fuel path (78, 143) is a fuel tank ( Purpose engine, characterized in that disposed in the 'so as to pass through) in the fuel tank (48, 48' 8,48) within.   In the tank cap (64, 130), an external communication path (80, 144) leading to the outside is formed and opened when the pressure in the fuel tank (48, 48 ') is lower than the external pressure. The general-purpose engine according to claim 1, further comprising a one-way valve (86, 150) for allowing the external communication passage (80, 144) to communicate with the fuel tank (48, 48 ').

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