JP2008045489A - General purpose internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a general purpose internal combustion engine which simplifies piping near a fuel injection part by removing a return pipe by preventing formation of vapor in a fuel supply pipe near the fuel injection part, and facilitates layout of piping. <P>SOLUTION: In an air cooled general purpose internal combustion engine (engine 10) provided with: a fuel injection part 24 injecting fuel (gasoline fuel); and a cooling fan 42 blasting suction air and performing cooling, a fan cover 44 covering a cooling fan 42 is provided, and a fuel injection part 24 is arranged near the fan cover 44. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a general-purpose internal combustion engine.

In general-purpose internal combustion engines that are used as drive sources in various applications such as generators and agricultural machines, fuel is generally supplied by a carburetor. However, in recent years, an apparatus that supplies fuel by a fuel pump and a fuel injection unit (fuel injection valve or the like), that is, a fuel supply apparatus that uses FI (Fuel Injection) has been proposed (see, for example, Patent Document 1). ).
JP 2002-349375 A (paragraphs 0018, 0024, FIGS. 1, 5, etc.)

  By the way, in the technique described in Patent Document 1, a regulator is provided on the downstream side of the fuel injection section, and the fuel exceeding the fuel consumption of the fuel injection section, that is, surplus fuel is supplied to the fuel tank via the return pipe. It is configured to reflux (return). For this reason, in the vicinity of the general-purpose internal combustion engine, particularly in the vicinity of the fuel injection portion, the configuration becomes complicated due to the return piping and the like, and there is a problem that the piping is troublesome.

  Therefore, in order to solve the problem, a regulator is provided on the upstream side of the fuel injection section, and the return pipe is removed by supplying fuel at a constant pressure to the fuel injection section, and the piping around the fuel injection section is routed. It is conceivable to make this easier.

  However, in the technique described in Patent Document 1, since the fuel injection unit is disposed in a position where the temperature becomes relatively high during operation, specifically, a space formed between the cylinders, Vapor (evaporated fuel (fuel vapor)) is generated in the fuel supply pipe near the section by heat received from the cylinder (particularly, heat received during hot soaking). For this reason, a pipe for returning the vapor to the fuel tank, that is, a return pipe is required, and it has been difficult to make a configuration for removing the return pipe as described above.

  Accordingly, the object of the present invention is to solve the above-described problems, prevent the generation of vapor in the fuel supply pipe near the fuel injection section, remove the return pipe, simplify the pipe near the fuel injection section, and route the pipe. It is an object of the present invention to provide a general-purpose internal combustion engine that facilitates the above.

  In order to solve the above-mentioned object, in claim 1, in the air-cooled general-purpose internal combustion engine including a fuel injection unit that injects fuel and a cooling fan that blows and cools intake air, the cooling is performed. A fan cover that covers the fan is provided, and the fuel injection unit is arranged in the vicinity of the fan cover.

  The general-purpose internal combustion engine according to claim 2 includes a plurality of cylinders arranged in a V shape around a crankshaft, and a V-shaped space in which the fuel injection portion is formed between the plurality of cylinders. It arrange | positioned adjacent to.

  In the general-purpose internal combustion engine according to claim 3, the fuel injection unit includes a fuel injection valve disposed in each of the plurality of cylinders, and a distribution pipe that distributes fuel in a fuel supply pipe to each of the fuel injection valves. It was made up of.

  The general-purpose internal combustion engine according to claim 4 further includes a first fuel pump disposed in a fuel supply pipe connecting a fuel tank and the fuel injection unit, and the first fuel in the fuel supply pipe. And a second fuel pump disposed on the upstream side of the pump.

  The general-purpose internal combustion engine according to claim 1 is provided with a fan cover that covers a cooling fan that blows and cools sucked air, and the fuel injection unit that injects fuel is used during operation of the general-purpose internal combustion engine or hot soak. Since it is arranged in the vicinity of the fan cover, which is a relatively low temperature at the time, that is, the fuel injection part is arranged in an environment in which it is difficult to receive heat from the cylinder or the like, Vapor generation in the fuel supply pipe can be prevented, and thus the return pipe can be removed (returnless). This simplifies the piping near the fuel injection section and facilitates piping. Further, since the return pipe is removed, the general-purpose internal combustion engine can be reduced in size by the return pipe. Furthermore, the stability of fuel injection can be improved by suppressing the generation of vapor.

  The general-purpose internal combustion engine according to claim 2 includes a plurality of cylinders arranged in a V shape around the crankshaft, and a fuel injection portion adjacent to a V-type space formed between the plurality of cylinders. In addition to the effects described above, the fuel injection part and the cylinder can be connected by a relatively short fuel supply pipe, that is, in the fuel supply pipe near the fuel injection part, It is possible to reduce the area (heat receiving area) that receives heat from the cylinder that becomes high temperature, and thus it is possible to further prevent the generation of vapor in the fuel supply pipe near the fuel injection portion.

  In the general-purpose internal combustion engine according to claim 3, the fuel injection unit is configured by a fuel injection valve disposed in each of the plurality of cylinders, and a distribution pipe that distributes fuel in a fuel supply pipe to each of the fuel injection valves. Thus, in addition to the effect described in claim 2, the generation of vapor in the distribution pipe connected to the fuel injection valve can be prevented.

  The general-purpose internal combustion engine according to claim 4 further includes a first fuel pump disposed in a fuel supply pipe connecting the fuel tank and the fuel injection unit, and an upstream of the first fuel pump in the fuel supply pipe. Since it comprised so that the 2nd fuel pump arrange | positioned by the side might be provided, the above-mentioned effect can be acquired further.

  The best mode for carrying out a general-purpose internal combustion engine according to the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a partially transparent plan view of a general-purpose internal combustion engine according to a first embodiment of the present invention. 2 is a side partial perspective view of the general-purpose internal combustion engine shown in FIG. 1 when viewed from the direction of arrow A. FIG. 3 is a side partial perspective view of the general-purpose internal combustion engine shown in FIG. FIG. 2 and 3 show only a part of the general-purpose internal combustion engine for the convenience of understanding the device for supplying the fuel.

  In FIG. 1, reference numeral 10 denotes a general-purpose internal combustion engine (hereinafter referred to as “engine”). A fuel supply device 12 that supplies fuel (gasoline; hereinafter referred to as “gasoline fuel”) to the engine 10 is connected to the engine 10.

  The fuel supply device 12 is a fuel that connects a main fuel tank 14 (not shown in FIG. 3) that stores fuel, and the main fuel tank 14 and the engine 10 (more precisely, a fuel injection valve (described later) of the engine 10). Supply pipe 16, high-pressure pump module 20 arranged in fuel supply pipe 16, low-pressure pump (second fuel pump) 22 arranged upstream of high-pressure pump module 20 in fuel supply pipe 16, gasoline fuel A fuel injection unit 24 that injects, a canister 26 (not shown in FIG. 3) that houses an adsorbent that adsorbs the evaporated fuel generated from the main fuel tank 14 and the like are provided.

  Hereinafter, each element which comprises the engine 10 and the fuel supply apparatus 12 is demonstrated.

  FIG. 4 is a side partial perspective view of the engine 10 as viewed from the direction of the arrow B.

  As shown in FIG. 4, the engine 10 includes a plurality of cylinders 32 arranged at different angles around the crankshaft 30, specifically, two cylinders arranged in a V shape. This is an air-cooled four-cycle V-type two-cylinder spark-ignited gasoline engine (displacement is 640 cc, for example) and is used as a drive source in various applications such as generators and agricultural machines.

  A piston (not shown) is accommodated in the cylinder (cylinder block) 32 of the engine 10 so as to be able to reciprocate. A cylinder head 34 is attached to the upper portion of the cylinder 32. The cylinder head 34 has a combustion chamber (not shown) formed at a position facing the top of the piston, an intake port 36 and an exhaust port ( (Not shown) is provided. Although not shown, the cylinder head 34 is provided with an intake valve that opens and closes between the combustion chamber and the intake port 36, an exhaust valve that opens and closes between the combustion chamber and the exhaust port, and the like.

  A non-illustrated load such as a generator is connected to one end of the crankshaft 30, and a recoil starter 40 (shown only in FIG. 3) that allows the engine 10 to be started manually by an operator. A cooling fan 42 that cools the sucked air by blowing it to the engine 10 is attached. The cooling fan 42 is covered with a fan cover 44, and the fan cover 44 is disposed adjacent to the cylinder 32.

  5 is a front view of the fan cover 44, and FIG. 6 is a cross-sectional view taken along the line VI-VI of the fan cover 44 shown in FIG.

  As shown in FIG. 5, the fan cover 44 is formed so as to have a shape conforming to the engine 10, more specifically, in the vicinity of the upper portion thereof, to have a V-shaped shape similar to the cylinder 32 of the engine 10. . As a result, a V-shaped (trapezoidal) space is formed above the fan cover 44. Hereinafter, this space is referred to as “fan cover upper space”, and is indicated by a broken line in FIG. The fan cover 44 is made of, for example, a resin material.

  In addition, a plurality of air intake holes 44a for taking in cooling air are provided at positions near the center of the fan cover 44 and close to the cooling fan 42 as shown in FIGS. Individually formed.

  Returning to the description of FIG. 4, the above-described fuel injection unit 24 is disposed in the fan cover upper space 46 of the fan cover 44. The fuel injection unit 24 includes a fuel injection valve (injector) 50 disposed in each of the two cylinders 32 (more precisely, in the vicinity of the intake port 36 of the cylinder 32), and a fuel supply pipe 16 for each of the fuel injection valves 50. It comprises a distribution pipe 52 for distributing gasoline fuel. The operation of the fuel injection valve 50 is controlled by an ECU (Electronic Control Unit; electronic control unit; shown in FIG. 1 and the like) 53 composed of a microcomputer.

  As described above, the fuel injection portion 24 of the engine 10 is disposed in the vicinity of the fan cover 44, specifically, in the fan cover upper space 46 formed in the upper portion of the fan cover 44, and It is arranged adjacent to a space formed between them (hereinafter referred to as “cylinder upper space” and indicated by reference numeral 54 in FIG. 1). The cylinder upper space 54 is located behind the cylinder upper space 46 in FIG. 4, and has a V shape (V shape) in a side view like the fan cover upper space 46.

  FIG. 7 is a schematic diagram schematically showing each element constituting the fuel supply device 12. In FIG. 7, the positional relationship of each element is shown relatively, and the upper side of the drawing is shown as being upward in the direction of gravity.

  The main fuel tank 14 stores gasoline fuel to be supplied to the engine 10. Further, a fuel filler port (not shown) is formed in the upper surface 14 a of the main fuel tank 14, and the fuel filler port is sealed with a cap (two-way valve cap) 60.

  A fuel injection unit 24 is connected to the lower surface 14 b of the main fuel tank 14 through a fuel supply pipe 16. As shown in FIG. 7, a filter 62, the low-pressure pump (second fuel pump) 22, and the high-pressure pump module 20 are disposed in the fuel supply pipe 16 in order from the upstream side. Hereinafter, the fuel supply pipe from the main fuel tank 14 to the high pressure pump module 20 is referred to as a “low pressure line” and is denoted by reference numeral 16a, and the fuel supply pipe from the high pressure pump module 20 to the fuel injection unit 24 is referred to as a “high pressure line”. Called 16b. In this specification, “upstream” and “downstream” mean upstream and downstream in the flow direction of gasoline fuel flowing therethrough.

  The filter 62 removes impurities such as dust in the passing gasoline fuel. Further, the low pressure pump 22 pumps the gasoline fuel stored in the main fuel tank 14 to the high pressure pump module 20 (more precisely, a sub fuel tank of the high pressure pump module 20 described later). The low-pressure pump 22 is specifically an electromagnetic diaphragm pump, and its operation is controlled by the ECU 53 described above.

  FIG. 8 is a partial cross-sectional view showing in detail the high-pressure pump module 20 shown in FIG. 7 and the like, and FIG. 9 is an exploded perspective view of the high-pressure pump module 20.

  As shown in FIGS. 8 and 9, the high pressure pump module 20 includes a sub fuel tank 64 that stores fuel supplied from the main fuel tank 14, and a high pressure pump (first fuel pump) that is accommodated in the sub fuel tank 64. 66, a suction filter 70 disposed near the suction port 66a of the high-pressure pump 66, a regulator 72 accommodated in the sub fuel tank 64, a top cover 74 covering the upper portion of the sub fuel tank 64, and the like.

  The sub fuel tank 64 has a substantially columnar shape (cylindrical shape), and an upper portion thereof is opened. A concave portion 64b having an appropriate height is formed on the lower surface 64a of the sub fuel tank 64 as shown in FIG. As will be described later, impurities such as moisture and dust in gasoline fuel are deposited and deposited in the recess 64b. The sub fuel tank 64 is made of, for example, aluminum.

  A high pressure pump 66 is accommodated inside the sub fuel tank 64 (internal space 64c). The suction port 66a of the high-pressure pump 66 is located at a lower position in the direction of gravity inside the sub fuel tank 64, more precisely, near the lower surface 64a of the sub fuel tank 64 and above the recess 64b of the sub fuel tank 64. Be placed. A suction filter 70 is attached to the suction port 66a to remove impurities such as dust in gasoline fuel passing therethrough.

  Further, the discharge port 66 b of the high-pressure pump 66 is disposed at an upper position in the direction of gravity inside the sub fuel tank 64. The high-pressure pump 66 pumps the gasoline fuel F stored in the sub fuel tank 64 to the fuel injection unit 24 (more precisely, the fuel injection valve 50 of the fuel injection unit 24) via the high-pressure line 16b. The high-pressure pump 66 is specifically an electric pump, and its operation is controlled by the ECU 53 described above.

  A top cover 74 that can be fitted into the opening 64d is disposed in the opening 64d in the upper portion of the sub fuel tank 64. The top cover 74 has a low pressure line communication portion 74a for communicating the sub fuel tank 64 and the low pressure line 16a, a high pressure line communication portion 74b for communicating the discharge port 66b of the high pressure pump 66 and the high pressure line 16b, A fuel return pipe communication portion 74c that connects the fuel tank 64 and a fuel return pipe 84 described later is formed.

  Like the high-pressure pump 66, the regulator 72 is housed in the sub fuel tank 64 and connected to the vicinity of the discharge port 66 b of the high-pressure pump 66 via the regulator flow path 86. The regulator 72 decompresses and regulates the gasoline fuel discharged from the high-pressure pump 66.

  The sub fuel tank 64 containing the high-pressure pump 66 and the like is covered with the top cover 74 as described above. More specifically, an O-ring (seal material) 76 is inserted in a connection portion between the opening 64 d of the sub fuel tank 64 and the top cover 74. A plate 80 having a substantially disk shape is arranged on the top surface of the top cover 74. The sub fuel tank 64, the top cover 74, and the plate 80 include a plurality of (specifically, six) bolts as shown in the figure. Fastened and fixed by 82. Thereby, the opening 64d of the sub fuel tank 64 is liquid-tightly sealed by the top cover 74, the O-ring 76, and the plate 80.

  Returning to the description of FIG. 7, the sub fuel tank 64 is connected to the upper surface 14 a of the main fuel tank 14 via the fuel return pipe communication portion 74 c and the fuel return pipe 84. That is, the internal space 64 c of the sub fuel tank 64 and the fuel tank 14 are communicated by the fuel return pipe 84.

  As shown in FIG. 7 and the like, the sub fuel tank 64 of the high-pressure pump module 20 configured as described above is positioned above the main fuel tank 14 in the gravitational direction. The sub fuel tank 64 of the high pressure pump module 20 is positioned below in the direction of gravity.

  In addition to the fuel return pipe 84, the canister 26 is connected to the upper surface 14 a of the main fuel tank 14 via the charge passage 90. The canister 26 is connected to the intake system of the engine 10, more specifically, to the intake port 36 via the purge passage 92. A purge control valve 94 composed of an electromagnetic valve is inserted in the middle of the purge passage 92. The purge control valve 94 opens and closes the purge passage 92 with an opening corresponding to the energization amount supplied to the solenoid, and its operation is controlled by the ECU 53.

  As a result, the gasoline fuel evaporated in the main fuel tank 14 (evaporated fuel (fuel vapor)) flows (charges) through the charge passage 90 to the canister 26. The evaporated fuel that has flowed into the canister 26, particularly the hydrocarbon (HC) component therein, is adsorbed by an adsorbent (not shown) accommodated inside the canister 26. When the purge passage 92 is opened, the evaporated fuel adsorbed by the adsorbent is desorbed by the negative pressure of the intake system (intake port 36) of the engine 10, and then the flow rate according to the opening of the purge passage 92 is reached. Thus, the air is sucked into the intake port 36 of the engine 10 and purged.

  The operation of the fuel supply device 12 configured as described above will be described with reference to FIG.

  First, when the low-pressure pump 22 is operated, impurities in the gasoline fuel in the main fuel tank 14 are removed by the filter 62, and the sub fuel tank 64 of the high-pressure pump module 20 is passed through the low-pressure line 16a and the low-pressure line communication portion 74a. To be stored (filled). At this time, impurities such as moisture and dust in the gasoline fuel are deposited and deposited in the recess 64b of the sub fuel tank 64.

  The gasoline fuel stored in the sub fuel tank 64 is sucked through the suction filter 70 from the suction port 66a of the high-pressure pump 66 (both are not visible in FIG. 7). Next, the high pressure pump 66 discharges high pressure gasoline fuel to the high pressure line 16b via the discharge port 66b and the high pressure line communication portion 74b. At this time, the gasoline fuel is regulated to an appropriate pressure by the regulator 72.

  The gasoline fuel regulated by the regulator 72 is supplied to the fuel injection unit 24 via the high-pressure line 16b. Specifically, the gasoline fuel in the high pressure line 16b is distributed to each fuel injection valve 50 by the distribution pipe 52 of the fuel injection unit 24, and is injected from the fuel injection valve 50 toward the intake port 36 to generate an air-fuel mixture. .

  Of the gasoline fuel supplied to the sub fuel tank 64 by the operation of the low pressure pump 22, gasoline fuel exceeding the capacity of the sub fuel tank 64, that is, surplus fuel is the fuel return pipe communication portion 74 c and the fuel return pipe 84. To return to the main fuel tank 14 (returned).

  Thus, in the fuel supply device for the engine 10 according to the first embodiment, the sub fuel tank 64 that stores the gasoline fuel supplied from the main fuel tank 14 and accommodates the high-pressure pump 66 therein is provided. Since the high pressure pump 66 is soaked in the gasoline fuel stored in the sub fuel tank 64, air is introduced into the fuel supply pipe (low pressure line 16a) from the main fuel tank 14 to the high pressure pump 66. Even when the accumulation occurs, the high-pressure pump 66 does not suck air because the air is discharged to the outside through the fuel return pipe 84 and the like in the sub fuel tank 64, that is, the fuel injection valve. At 50, gasoline fuel can be injected immediately, thus improving startability.

  Further, since impurities such as moisture and dust in the gasoline fuel are deposited at the bottom of the sub fuel tank 64, specifically, the recess 64b, it is possible to make it difficult for the impurities to be directly supplied to the high pressure pump 66. At 66, a failure such as clogging can be prevented.

  Further, the suction port 66a of the high-pressure pump 66 is arranged at a lower position in the direction of gravity inside the sub fuel tank 64, that is, the air released to the sub fuel tank 64 moves upward. Since the suction port 66a of the high-pressure pump 66 is arranged at a lower position, the high-pressure pump 66 can be further prevented from sucking air, and startability can be improved.

  Further, the fuel return pipe 84 connecting the main fuel tank 14 and the sub fuel tank 64 is provided. In other words, the gasoline fuel supplied to the sub fuel tank 64 exceeds the capacity of the sub fuel tank 64. Since the gasoline fuel, that is, the surplus fuel is recirculated (returned) to the main fuel tank 14 via the fuel return pipe 84, the sub fuel tank 64 can be always filled with the gasoline fuel.

  In addition, since the fuel supply pipe 16 is configured to include the low-pressure pump 22 disposed on the upstream side of the sub fuel tank 64, specifically, regardless of the positional relationship between the main fuel tank 14 and the sub fuel tank 64, Even when the main fuel tank 14 is positioned below the sub fuel tank 64 in the direction of gravity, the fuel in the main fuel tank 14 can be reliably supplied to the sub fuel tank 64.

  Further, since the main fuel tank 14 is configured to be positioned below in the gravity direction of the sub fuel tank 64, the above-described effects can be obtained.

  In addition, the engine 10 according to the first embodiment includes the fan cover 44 that covers the cooling fan 42 that blows and cools the intake air, and the fuel injection unit 24 that injects the fuel is operated in the engine 10. It is configured to be arranged in the vicinity of the fan cover 44 (fan cover upper space 46), which is a relatively low temperature place at the time of hot or soak, that is, the environment in which the fuel injection part 24 is not easily subjected to heat from the cylinder 32 or the like. Since it is arranged below, it is possible to prevent the generation of vapor in the fuel supply pipe (for example, the high-pressure line 16b) in the vicinity of the fuel injection section 24, and thus the return pipe can be removed (returnless). it can. This simplifies the piping near the fuel injection unit 24 and facilitates the piping. Further, since the return pipe is removed, the engine 10 can be reduced in size by the amount of the return pipe. Furthermore, the stability of fuel injection can be improved by suppressing the generation of vapor.

  In addition, a plurality (two) of cylinders 32 arranged in a V shape with the crankshaft 30 as the center are provided, and the fuel injection portion 24 is provided in a V-type cylinder upper space 54 formed between the two cylinders 32. Since the fuel injection unit 24 and the cylinder 36 can be connected by a relatively short fuel supply pipe because they are arranged adjacent to each other, that is, the fuel supply pipe near the fuel injection unit 24 has a high temperature during operation. Thus, the area receiving heat from the cylinder 36 (heat receiving area) can be reduced, and therefore vapor generation in the fuel supply pipe near the fuel injection section 24 can be further prevented.

  The fuel injection unit 24 includes a fuel injection valve 50 disposed in each of a plurality (two) of cylinders 32, and a distribution pipe that distributes gasoline fuel in a fuel supply pipe (high-pressure line 16b) to each of the fuel injection valves 50. 52, the generation of vapor in the distribution pipe 52 connected to the fuel injection valve 50 can be prevented.

  Further, a high-pressure pump 66 disposed in the fuel supply pipe 16 connecting the main fuel tank 14 and the fuel injection unit 24 and a low-pressure pump 22 disposed upstream of the high-pressure pump 66 in the fuel supply pipe 16 are provided. Since it comprised so that it might comprise, the above-mentioned effect can be acquired further.

  Next, an engine 10 according to a second embodiment of the present invention will be described.

  FIG. 10 is a schematic view similar to FIG. 7 showing the fuel supply device 12a of the engine 10 according to the second embodiment of the present invention. In addition, about the structure common to 1st Example, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  The description will focus on the differences from the first embodiment. In the second embodiment, the main fuel tank 14 is positioned above the sub fuel tank 64 of the high pressure pump module 20 in the direction of gravity, and the low pressure The filter 62 and the low-pressure pump 22 are removed in the line 16a. The main fuel tank 14 according to the second embodiment is shown by a one-dot chain line in FIG. Hereinafter, the operation of the fuel supply device 12a will be described.

  The gasoline fuel stored in the main fuel tank 14 falls and is stored in the sub fuel tank 64 of the high-pressure pump module 20 disposed below in the direction of gravity by its own weight. Since the flow of the gasoline fuel stored in the sub fuel tank 64 is the same as that described in the first embodiment, the description thereof is omitted.

  Of the gasoline fuel supplied from the main fuel tank 14 to the sub fuel tank 64, surplus fuel evaporates (becomes vapor) and returns to the main fuel tank 14 via the fuel return pipe 84.

  Thus, in the fuel supply device 12a of the engine 10 according to the second embodiment, the main fuel tank 14 is disposed above the sub fuel tank 64 of the high pressure pump module 20 in the direction of gravity, and the low pressure pump 22 and the like. Therefore, the same effect as that of the first embodiment can be obtained while the configuration is simpler than that of the first embodiment.

  As described above, in the first and second embodiments of the present invention, the air-cooled type including the fuel injection section 24 for injecting fuel (gasoline fuel) and the cooling fan 42 for blowing and cooling the suction air. The general-purpose internal combustion engine (engine 10) includes a fan cover 44 that covers the cooling fan, and the fuel injection unit 24 is disposed in the vicinity of the fan cover 44.

  In addition, a plurality of (two) cylinders (cylinders 32) arranged in a V shape around the crankshaft 30 are provided, and the fuel injection portion 24 is formed in a V-shaped space formed between the plurality of cylinders ( The cylinder is arranged so as to be adjacent to the cylinder upper space 54).

  The fuel injection section 24 includes a fuel injection valve 50 disposed in each of the plurality of cylinders (32), and a distribution pipe 52 that distributes fuel in the fuel supply pipe 16 to each of the fuel injection valves. It was to so.

  In the first embodiment of the present invention, the first fuel pump (high pressure pump) disposed in the fuel supply pipe 16 connecting the fuel tank (main fuel tank 14) and the fuel injection section 24 is further provided. 66) and a second fuel pump (low pressure pump 22) disposed upstream of the first fuel pump in the fuel supply pipe 16.

  In the above description, the low pressure pump 22 is operated in accordance with the fuel injection amount of the engine 10. Specifically, the minimum required gasoline fuel is supplied from the main fuel tank 14 to the sub fuel tank 64 by the ECU. In addition, by controlling the supply amount, it is possible to achieve power saving and low emission.

1 is a partially transparent plan view of a general-purpose internal combustion engine according to a first embodiment of the present invention. FIG. 2 is a side perspective view of the general-purpose internal combustion engine shown in FIG. 1 when viewed from the direction of arrow A. FIG. 2 is a side partial perspective view of the general-purpose internal combustion engine shown in FIG. FIG. 2 is a side perspective view of the general-purpose internal combustion engine shown in FIG. FIG. 4 is a front view of the fan cover shown in FIG. 3. FIG. 6 is a cross-sectional view taken along line VI-VI of the fan cover shown in FIG. 5. It is a schematic diagram which shows typically each element which comprises the fuel supply apparatus shown in FIG. It is a fragmentary sectional view showing the high-pressure pump module shown in FIG. 7 etc. in detail. It is a disassembled perspective view of the high pressure pump module shown in FIG. FIG. 8 is a schematic view similar to FIG. 7 showing a fuel supply device for a general-purpose internal combustion engine according to a second embodiment of the present invention.

Explanation of symbols

  10 engine (general-purpose internal combustion engine), 14 main fuel tank (fuel tank), 16 fuel supply pipe, 22 low pressure pump (second fuel pump), 24 fuel injection section, 30 crankshaft, 32 cylinder (cylinder), 42 cooling Fan, 46 Fan cover, 50 Fuel injection valve (fuel injection part), 52 minute pipe (fuel injection part), 54 Cylinder upper space (space), 66 High pressure pump (first fuel pump)

Claims (4)

  An air-cooled general-purpose internal combustion engine that includes a fuel injection unit that injects fuel and a cooling fan that blows and cools suction air, and includes a fan cover that covers the cooling fan, and the fuel injection unit is connected to the fan A general-purpose internal combustion engine characterized by being arranged in the vicinity of a cover.   A plurality of cylinders arranged in a V shape with a crankshaft as a center are provided, and the fuel injection portion is arranged adjacent to a V-shaped space formed between the plurality of cylinders. The general-purpose internal combustion engine according to claim 1.   3. The fuel injection unit includes a fuel injection valve disposed in each of the plurality of cylinders, and a distribution pipe that distributes fuel in a fuel supply pipe to each of the fuel injection valves. The general-purpose internal combustion engine described.   Further, a first fuel pump disposed in a fuel supply pipe connecting the fuel tank and the fuel injection unit, and a second fuel pump disposed in the fuel supply pipe upstream of the first fuel pump. The general-purpose internal combustion engine according to claim 1, wherein the general-purpose internal combustion engine is provided.

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