General-purpose engine unit

Abstract

This invention provides a general-purpose engine unit that enables a catch tank for temporarily storing fuel to function properly. [Solution] In a general-purpose engine unit (1) configured by arranging a fuel tank (2) and an air cleaner box (10) horizontally above an engine (E), a catch tank (50) is provided, which is located close to the air cleaner box (10) and stores evaporated fuel generated inside the fuel tank (2), and a fuel tube (6) is provided to send the evaporated fuel from the fuel tank (2) to the catch tank (50). The catch tank (50) is provided above the engine (E) and between the fuel tank (2) and the air cleaner box (10).

Description

Technical Field

[0006] , , , ,

[0005] , , , , <​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​

[0007] To achieve the above objective, the present invention provides a general-purpose engine unit (1) configured by arranging a fuel tank (2) and an air cleaner box (10) horizontally above an engine (E), wherein the unit comprises a catch tank (50) positioned close to the air cleaner box (10) and storing evaporated fuel generated inside the fuel tank (2), and a fuel tube (6) that sends the evaporated fuel from the fuel tank (2) to the catch tank (50), the first feature being that the catch tank (50) is located above the engine (E) and between the fuel tank (2) and the air cleaner box (10).

[0008] Furthermore, a second feature is that an air intake port (18) is provided at the bottom of the air cleaner box (10), and the catch tank (50) is arranged along the edge (18b) of the air intake port (18).

[0009] Furthermore, the catch tank (50) is provided with a connection portion (54) to which one end of the fuel tube (6) is connected, and a rib (52) is provided near the connection portion (54) that extends perpendicularly to the intake direction line (18a) of the intake port (18), and the intake direction line (18a) is positioned within the width of the rib (52) when viewed from the connection direction of the fuel tube (6), which is a third feature.

[0010] Furthermore, a fourth feature is that, when viewed perpendicular to the intake direction line (18a), at least a portion of the intake port (18) is positioned within the width of the rib (52), and the rib (52) and the intake port (18) overlap along the intake direction line (18a).

[0011] Furthermore, the catch tank (50) has a fifth feature in that the wall portion (55) arranged along the edge (18b) is thicker than the other wall portions.

[0012] Furthermore, a sixth feature is that the catch tank (50) is directly attached to the bottom wall (17) of the air cleaner box (10).

[0013] Furthermore, a seventh feature is that the catch tank (50) is configured to be under negative pressure while the engine (E) is in operation. [Effects of the Invention]

[0014] According to the first feature, the length of the fuel tube can be kept short, and the fuel tube can be positioned above the engine. This prevents the fuel tube from being heated by the engine's heat, thus suppressing the cooling and liquefaction of evaporated fuel inside the fuel tube.

[0015] According to the second feature, by positioning the catch tank along the edge of the air intake of the air cleaner box, the catch tank itself can be used as a guide to efficiently direct air to the intake.

[0016] According to the third feature, the ribs protect the connection points, and the air hitting the ribs is guided to the intake port, thereby improving intake efficiency.

[0017] According to the fourth feature, the ribs can enhance the effect of guiding air to the intake port.

[0018] According to the fifth feature, it is possible to suppress the cooling of evaporated fuel in the catch tank by the air introduced into the intake port. Furthermore, by making the wall thickness thicker only in the area where the air introduced into the intake port hits, it is possible to increase the support strength of the connection part while keeping the weight increase of the catch tank to a minimum.

[0019] According to the sixth feature, the catch tank can enhance the effect of directing air to the air intake.

[0020] According to the seventh feature, it is possible to prevent the evaporated fuel discharged from the catch tank from flowing out to the outside and effectively send the evaporated fuel inside the catch tank to the air cleaner box.

Brief Description of the Drawings

[0021] [Figure 1] It is a front view of a general-purpose engine unit according to an embodiment of the present invention. [Figure 2] It is a rear view of a general-purpose engine unit. [Figure 3] It is a plan view of a general-purpose engine unit. [Figure 4] It is a left side view of a general-purpose engine unit. [Figure 5] It is a front view of the state where the cover member of the air cleaner box is removed from the general-purpose engine unit of FIG. 1. [Figure 6] It is a partially enlarged view of FIG. 1. [Figure 7] It is a sectional view taken along line VII-VII of FIG. 1. [Figure 8] It is a perspective view showing the shape of the rib. [Figure 9] It is a sectional view taken along line IX-IX of FIG. 7. [Figure 10] It is a perspective view showing the internal state of the catch tank when the general-purpose engine unit is overturned with the recoil starter down. [Figure 11] It is a perspective view showing the internal state of the catch tank when the general-purpose engine unit is overturned with the cylinder head down. [Figure 12] It is a perspective view showing the internal state of the catch tank when the general-purpose engine unit is overturned with the output shaft down. [Figure 13] It is a perspective view showing the internal state of the catch tank when the general-purpose engine unit is overturned with the control unit down.

Modes for Carrying Out the Invention

[0022] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. Figure 1 is a front view of a general-purpose engine unit 1 according to one embodiment of the present invention. Figure 2 is a rear view of the general-purpose engine unit 1, Figure 3 is a top view of the general-purpose engine unit 1, and Figure 4 is a left side view of the general-purpose engine unit 1.

[0023] The general-purpose engine unit 1, used as a power source for work machinery and the like, has a configuration in which a fuel tank 2, an air cleaner box 10, and a muffler 20 are integrally arranged on top of the engine E, which is a 4-stroke single-cylinder internal combustion engine. A recoil starter 40 for starting the engine E is located at the front of the crankcase 41 of the engine E. The recoil starter 40 houses a pulley (not shown) around which a string member connected to a handle 42 is wound. When the user pulls the handle 42 upward, a crankshaft (not shown) connected to the pulley rotates.

[0024] A control unit 30, equipped with operating switches 31 and 32, is located on the right side of the crankcase 41. A cylinder 43, which houses the piston of engine E so that it can reciprocate, is fixed to the left side of the crankcase 41, and a cylinder head 44, which houses the intake and exhaust mechanism, is fixed to the top of the cylinder 43. An exhaust pipe 21, connected to the bottom of the muffler 20, is connected to the rear of the cylinder head 44. An intake pipe 12, connected to the bottom of the air cleaner box 10, is connected to the front of the cylinder head 44. An output shaft 45, which rotates synchronously with the crankshaft, protrudes from the rear of the crankcase 41.

[0025] Below the fuel cap 3 of the fuel tank 2, a guide 4 is provided to guide fuel to the fuel pump. A charge pipe 5 is connected to this guide 4 to guide evaporated fuel generated inside the fuel tank 2 to the bottom of the fuel tank 2. The tip of the charge pipe 5 is connected to a charge tube 6, which serves as a fuel tube. A catch tank 50, which serves as a container for storing condensed evaporated fuel, is connected to the tip of the charge tube 6. The catch tank 50 is mounted at the bottom of the air cleaner box 10, and a drain hose 51 is connected to the bottom of the catch tank 50.

[0026] Figure 5 is a front view of the general-purpose engine unit 1 of Figure 1 with the cover member 14 of the air cleaner box 10 removed. Figure 6 is a partially enlarged view of Figure 1. The same reference numerals indicate the same or equivalent parts. The air element 13 is located on the upper part of the bottom wall 17 of the air cleaner box 10. The bottom wall 17 is provided with an intake port 18 whose intake direction line 18a is oriented vertically. A cylindrical intake guide 19 extending upward is connected to the edge of the intake port 18.

[0027] The evaporated fuel generated inside the fuel tank 2 is guided to the catch tank 50 via the charge pipe 5 and charge tube 6. In the general-purpose engine unit 1 according to this embodiment, the catch tank 50, which stores the fuel F produced by the condensation of evaporated fuel, is located above the engine E and between the fuel tank 2 and the air cleaner box 10. This makes it possible to keep the length of the charge tube 6 short and to position the charge tube 6 above the engine E. As a result, the heat from the engine E warms the charge tube 6, suppressing the cooling and liquefaction of the evaporated fuel inside the charge tube 6.

[0028] Figure 7 is a cross-sectional view taken along line VII-VII in Figure 1. Figure 8 is a perspective view showing the shape of the rib 52. The same reference numerals indicate the same or equivalent parts. The catch tank 50 has a shape in which the front-to-back dimension is larger than the left-to-right dimension. A cylindrical connector 54 for connecting one end of the charge tube 6 is provided on the right side of the catch tank 50. The connector 54 is positioned slightly below the center of the vertical dimension of the catch tank 50.

[0029] A curved, plate-shaped rib 52 is provided in front of the connection portion 54, extending perpendicularly to the intake direction line 18a of the intake port 18. In this embodiment, at least a portion of the rib 52 is configured to overlap with the intake port 18 when viewed from the direction of the intake direction line 18a. This allows the connection portion 54 to be protected by the rib 52, and the air hitting the rib 52 is guided to the intake port 18, thereby improving intake efficiency. Furthermore, at least a portion of the intake port 18 is positioned within the width of the rib 52 when viewed perpendicular to the intake direction line 18a, and the rib 52 and the intake port 18 are configured to overlap along the intake direction line 18a, while the intake direction line 18a is positioned within the width of the rib 52 when viewed from the connection direction of the fuel tube 6. This further enhances the effect of the rib 52 in guiding air to the intake port 18.

[0030] Figure 9 is a cross-sectional view taken along line IX-IX of Figure 7. The same reference numerals indicate the same or equivalent parts. A drain pipe 53 is provided at the lower end of the catch tank 50, to which a drain tube 51 is connected. A cylindrical outlet member 15 with an outlet hole 16 is provided on the bottom wall 17 of the air cleaner box 10 to which the catch tank 50 is attached, for guiding the evaporated fuel temporarily stored in the catch tank 50 into the interior of the air cleaner box 10.

[0031] In the general-purpose engine unit 1 according to this embodiment, the air cleaner box 10 and the catch tank 50 are electrically connected, so that the inside of the catch tank 50 becomes negative pressure while the engine E is running. For example, it can be configured so that the pressure is -77.2 Pa when the engine speed is 3600 rpm and -0.1 Pa when it is 1400 rpm. This makes it possible to effectively send evaporated fuel inside the catch tank 50 to the air cleaner box 10.

[0032] The air intake port 18 of the air cleaner box 10 is formed slightly to the right of the bottom wall 17. The catch tank 50 is directly attached to the lower part of the bottom wall 17 along the edge 18b of the air intake port 18. This makes it possible to use the catch tank 50 itself as a guide to efficiently direct air to the air intake port 18. In addition, the wall portion 55 of the catch tank 50 that is arranged along the edge 18b of the air intake port 18 is thicker than the other wall portions. This makes it possible to suppress the cooling of evaporated fuel stored in the catch tank 50 by the air directed to the air intake port 18. Furthermore, by making only the wall portion 55 that is hit by the air directed to the air intake port 18 thicker, it is possible to increase the support strength of the connection portion 54 while suppressing the increase in the weight of the catch tank 50.

[0033] Figure 10 is a perspective view showing the internal state of the catch tank 50 when the general-purpose engine unit 1 is overturned with the recoil starter 40 facing downwards. Figure 11 is a perspective view showing the internal state of the catch tank 50 when the general-purpose engine unit 1 is overturned with the cylinder head 44 facing downwards. Figure 12 is a perspective view showing the internal state of the catch tank 50 when the general-purpose engine unit 1 is overturned with the output shaft 45 facing downwards. Figure 13 is a perspective view showing the internal state of the catch tank 50 when the general-purpose engine unit 1 is overturned with the control unit 30 facing downwards. The same reference numerals indicate the same or equivalent parts.

[0034] In this embodiment, the general-purpose engine unit 1 is designed so that the stored fuel F does not leak out of the catch tank 50 regardless of the direction in which the engine rolls over. This is achieved by setting the shape and capacity of the catch tank 50, as well as the placement of the outlet member 15, the connection part 54 to which the charge tube 6 is connected, and the drain pipe 53 to which the drain tube 51 is connected. As a result, even when using a catch tank 50 as a general-purpose container instead of a canister, it is possible to make the catch tank 50 function well and reduce costs.

[0035] The configuration of the general-purpose engine unit, the type of engine, the shape and structure of the fuel tank and air cleaner box, the length and routing method of the charge pipe and charge tube, the shape and structure of the catch tank, the shape and structure of the ribs, etc., are not limited to the above-described embodiment and can be modified in various ways. [Explanation of symbols]

[0036] 1…General-purpose engine unit, 2…Fuel tank, 6…Charging tube (fuel tube), 10…Air cleaner box, 17…Bottom wall of air cleaner box, 18…Air intake, 18a…Intake direction line of air intake, 18b…Edge of air intake, 50…Catch tank, 52…Rib, 54…Connection part, 55…Wall part, E…Engine, F…Fuel

Claims

1. In a general-purpose engine unit (1) configured by arranging a fuel tank (2) and an air cleaner box (10) horizontally above the engine (E), A catch tank (50) is positioned in close proximity to the air cleaner box (10) and stores evaporated fuel generated inside the fuel tank (2), The system comprises a fuel tube (6) that sends the evaporated fuel from the fuel tank (2) to the catch tank (50), A general-purpose engine unit characterized in that the catch tank (50) is provided above the engine (E) and between the fuel tank (2) and the air cleaner box (10).

2. An air intake port (18) is provided at the bottom of the aforementioned air cleaner box (10). The general-purpose engine unit according to claim 1, characterized in that the catch tank (50) is disposed along the edge (18b) of the intake port (18).

3. The catch tank (50) is provided with a connection part (54) to which one end of the fuel tube (6) is connected. Near the connection portion (54), a rib (52) is provided that extends perpendicularly to the intake direction line (18a) of the intake port (18). The general-purpose engine unit according to claim 2, characterized in that the intake direction line (18a) is arranged within the width of the rib (52) when viewed from the connection direction of the fuel tube (6).

4. The general-purpose engine unit according to claim 3, characterized in that, when viewed perpendicular to the intake direction line (18a), at least a portion of the intake port (18) is positioned within the width of the rib (52), and the rib (52) and the intake port (18) overlap along the intake direction line (18a).

5. The general-purpose engine unit according to claim 2, characterized in that the catch tank (50) is configured such that the wall portion (55) arranged along the edge (18b) is thicker than the other wall portions.

6. The general-purpose engine unit according to claim 3, characterized in that the catch tank (50) is directly attached to the bottom wall (17) of the air cleaner box (10).

7. The general-purpose engine unit according to claim 1 or 2, characterized in that the inside of the catch tank (50) is configured to be under negative pressure while the engine (E) is in operation.

Images