JPH08232654A - Air-cooled internal combustion engine - Google Patents

Abstract

PURPOSE: To improve a cooling function and a discharge air processing function, in an air-cooled internal combustion engine. CONSTITUTION: A cooling fan and a fan case are provided in an opposite side to a power take out side, and a cooling air passage 33 for cooling air to pass from a cooling fan side to the power take out side is formed in a cylinder head 7, to form a cooling air passage 32 for cooling air to pass from the cooling fan side to the power take out side in a cylinder 2. In a cooling air outlet in a power take out side of the cylinder head 7 and the cylinder 2, a discharge air flange 38 of enveloping together these members is formed, to make a discharge air duct or a discharge air guide 42 mountable in the discharge air flange 38 and demountable from it. In a cylinder head cover 8 fixed to an upper side of the cylinder head 7, a fuel injection valve chamber separated from a rocker arm chamber is integrally formed, so as to make cooling air of the cooling air passage 33 pass through the fuel injection valve chamber. In this way, a cooling function is improved.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an air-cooled internal combustion engine.

[0002]

2. Description of the Related Art Regarding the cooling structure of this type of air-cooled internal combustion engine, for example, in Japanese Utility Model Publication No. Sho 63-20821, the cooling air sent from the cooling fan into the cylinder head is dispersed in different directions and discharged. It is like this. Further, regarding the fuel injection valve, the fuel injection valve is not covered by the cylinder head cover.

[0003]

If the cooling air sent from the cooling fan into the cylinder head is dispersed in different directions and exhausted, it is easy to collect the exhausted air at one place. Not. In particular, when the exhaust air is dispersed when it is mounted on a work machine, the exhaust air processing structure becomes complicated.

Further, regarding the fuel injection valve, if the fuel injection valve is exposed from the cylinder head cover, there is a problem such as noise emitted from around the nozzle.

The inventions set forth in claims 1 and 2 are intended to solve the above problems and improve the cooling function by devising the flow of the cooling air from the cooling fan.

[0006]

In order to solve the above-mentioned problems, the invention according to claim 1 of the present application provides a cooling fan 17 and a fan case 18 on the side opposite to the power take-out side, and cools inside the cylinder head 7. A cooling air passage 33 for passing cooling air from the fan side to the power extraction side is formed, and a cooling air passage 32 for allowing cooling air to pass from the cooling fan side to the power extraction side is formed in the cylinder 2, and the cylinder head 7 and the cylinder 2 are formed. A cooling air outlet on the power take-out side is formed with a cooling air exhausting flange 38 surrounding them, and a cooling air exhausting duct 59 is formed on the cooling air exhausting flange 38.
Alternatively, the exhaust guide 42 and the like can be attached and detached.

As a result, the cooling air from the cooling fan 17 flows through the head-side cooling air passage 33 and the cylinder-side cooling air passage 32 in one direction toward the power take-out side, and is all collected and discharged from the power take-out side. The cooling function is improved and the exhaust air treatment is facilitated.

According to a second aspect of the invention, the cylinder head 7
A cooling air passage 33 is formed therein for passing cooling air from the cooling fan side to the power take-out side, and fuel injection isolated from the rocker arm chamber 47 is provided in the cylinder head cover 8 fixed to the upper side of the cylinder head 7. The valve chamber 46 is integrally formed, and the end of the fuel injection valve chamber 46 on the cooling fan side is communicated with the upstream side of the head side cooling air passage 33 through the cooling air intake hole 49a on the upper wall of the cylinder head. The end of the fuel injection valve chamber 46 on the power take-out side is communicated with the downstream side of the head side cooling air passage 33 via the cooling air outlet hole 49b of the cylinder head upper wall.

As a result, the sound emitted from the fuel injection valve 43 can be shielded and the fuel injection valve 43 can be positively cooled.

[0010]

1 to 10 show a horizontal axis type air-cooled internal combustion engine to which the invention described in claims 1 and 2 is applied.
1, which shows a front view as seen from the power take-out side in the crankshaft length direction, the engine body is composed of a cylinder block 1, a cylinder head 7, etc., and the cylinder block 1 integrally includes a cylinder 2 and a crankcase portion 3. I have it. An air cleaner 9 is arranged on the right side of the cylinder 2, an exhaust muffler 10 is arranged on the left side, and a cylinder head cover 8 is fixed to the upper surface of the cylinder head 7.

In the crankcase portion 3, a horizontal crankshaft 12 is supported in the same vertical plane as the cylinder centerline C,
A balancer shaft and a cam shaft 14 are arranged in the crankcase portion 3 on the air cleaner side (right side) of the crankshaft 12,
A starter motor 29 is arranged on the side of the crankcase portion on the exhaust muffler side (left side). The camshaft 14 is the crankshaft 1
2, the balancer shaft 13 and the shaft portion O2 of the starter motor 29 are both located below the crankshaft 12, thereby lowering the center of gravity of the entire engine.
The starter motor 29 includes a bracket 30 formed on the crankcase portion 3, a solenoid 31 on the upper side, and a bolt 31.
It is attached by. The exhaust muffler 10 is vertically arranged above the starter motor 29.

A balancer driven gear 24 and a camshaft drive gear 25 are provided on the balancer shaft 13 in the gear case on the power take-out side of the crankcase portion 3, and the balancer damage drive gear 24 meshes with the gear 23 of the crankshaft 12. ,
The cam shaft drive gear 25 meshes with the cam gear 26, and rotates the cam shaft 14 in the same direction as the crank shaft 12.

A cylinder side cooling air passage 32 is formed around the cylinder 2 from the side (cooling fan side) opposite to the power take-out side to the power take-out side, and the power take-out side is also provided in the cylinder head 7. A head side cooling air passage 33 is formed to allow cooling air to flow only from the opposite side (cooling fan side) to the power take-out side, and the exhaust port 34 of the cylinder head 7 is open to the power take-out side. The exhaust muffler 10 is formed with a primary expansion chamber / exhaust pipe 41 which is long in the vertical direction and has a large volume so as to cover the power take-out side of the cylinder head 7 and the cylinder 2, and is connected to the exhaust port 34. ing.

Around the power take-out side of the cylinder head 7 and the cylinder 2, there is formed an exhaust air flange 38 which surrounds both the cooling air passages 32 and 33, and the exhaust air flange 38 of FIG. In such a single engine, the exhaust guide 42 is fixed by bolts.

In FIG. 2, a fuel tank 19 is arranged on the side opposite to the power take-out side.
Extends in the left-right direction to the full width of the exhaust muffler 10 and the air cleaner 9. That is, the fuel tank 19, the air cleaner 9, the exhaust muffler 10, and the primary expansion chamber / exhaust pipe 41 surround all four sides of the cylinder.

In FIG. 3, a cooling fan 17 and a fan case 18 that covers the cooling fan 17 are provided on the side opposite to the power take-out side, and the fuel tank 1 is provided above the fan case 18.
9 are arranged.

In FIG. 4, the fan case mounting surfaces 53 of the cylinder block 1 and the cylinder head 7 are aligned in the same vertical plane, and the fan case 18 is attached to the mounting surface 53.
Are attached via a seal 65. The upper end of the fan case 18 is an inclined surface 18a.
The mounting plate 54 of the fuel tank 19 is placed on the 8a with the vibration absorbing member 64 interposed therebetween. Upper and lower brackets 55 and 56 are provided at the upper and lower ends of the mounting plate 54, and the lower bracket 56 is fixed to the side surface of the fan case 18 together with the lower end of the mounting plate 54 without a vibration isolation mechanism. As shown in FIG. 8, 55 is anti-vibration supported to the upper end of the cylinder head 7 via the anti-vibration rubber damper 63 together with the upper end of the mounting plate, and is fixed by the bolt 61.

As shown in FIG. 9, the fan case 18 itself is vibration-supported by the cylinder block 1 and the like via a vibration damper 66, and is fixed by bolts 68. In FIG. 5, which shows a horizontal cross-sectional view of the cylinder head 7, the head side cooling air passage 33 includes three branch passages 33-A, 33-B and 3
3-C, but which branch passage 33-
A, 33-B, and 33-C are also shaped to allow the cooling air to pass only from the cooling fan side to the power take-out side. 36 is an intake port.

FIG. 6 is a vertical sectional view of the cylinder head cover 8. The cylinder head cover 8 has a fuel injection valve chamber 46 which is separated from a rocker arm chamber 47 which houses the rocker arm 44 and which integrally has a cover wall 46a. Has been formed.

In FIG. 7 showing a section taken along line VII-VII of FIG.
A cooling air intake hole 49a is formed on the upper wall of the cylinder head to connect the fan-side end of the fuel injection valve chamber 46 and the fan-side end of the head-side cooling air passage 33 with the fuel injection valve. Power extraction side end of chamber 46 and head side cooling air passage 3
Cooling air outlet hole 49b communicating with the end of the power take-out side of No. 3
Thus, a part of the cylinder head cooling air is guided to the fuel injection valve chamber 46 to positively cool the fuel injection valve 43.

The flow of cooling air will be described. Cooling fan 17
The cooling air drawn from outside by the fan case 18
The cooling air in the cylinder 2 and the cylinder head 7 enters into the cooling air passages 32 and 33, and a part of the cooling air in the cylinder head 7 is further injected into the fuel injection valve chamber 4 of the cylinder head cover 8.
6, the cylinder 2, the cylinder head 7 and the fuel injection valve 43 are cooled respectively. All of these cooling winds are discharged from the power take-out side. Exhaust flange 3 as shown in Figure 1
When the exhaust air guide 42 is attached to the unit 8, the cooling exhaust air is guided to the guide 42.

In FIG. 10, the cooling fan 17 is made of resin separately from the flywheel 50, and the cooling fan 17 is in close contact with the outer circumference of the start pulley 70 fixed to the flywheel 50. The cooling air is sucked in from the outside of the start pulley 70 in the axial direction by the cooling fan 17. The outer peripheral shape of the contact portion of the start pulley 70 is 1
As shown by 7b, it is formed in a curved shape along the flow of the cooling air.

Since the separate resin fan 17 is closely attached to the outer periphery of the start pulley 70, the start pulley 70 can be damped and the shape along the cooling air can be easily formed, and the flow rate of the cooling air can be increased. You can Further, by creating a smooth flow of cooling air, the wind noise caused by the fan blades 17a can be reduced. By using the cooling fan 17 that is separate from the flywheel 50, holes can be formed in the flywheel 50 without reducing the cooling air flow rate. Can be made lighter.

The structure of the air cleaner 9, the fuel injection pump 112, the intake passage 111, etc. will be described in detail. In FIG. 1, the intake passage 111 opens to the right side of FIG. 1, and the fuel injection pump 112 is arranged on the intake passage inlet 111a side. Is
It is attached to the crankcase part 3. The angle α of the fuel injection pump 112 with respect to the cylinder center line is attached at a small angle (for example, 20 °), and the fuel injection pump 112 is mounted on the fuel injection valve 43 via the fuel high pressure pipe 113.
(FIG. 6).

The air cleaner 9 arranged on the fuel injection pump arrangement side (right side) with respect to the cylinder head 7 has a wide shape and a large volume so as to cover substantially the entire surfaces of the cylinder head 7 and the intake passage inlet side of the cylinder 2. Has been formed.

The air cleaner 9 has a resin air cleaner main body 116 and an air cleaner lid 117, and the air cleaner main body 116 is spaced from the air cleaner mounting surface 114 of the cylinder head 3 by a predetermined distance. The fuel injection pump 1 is provided between the air cleaner main body 116 and the air cleaner mounting surface 114 and below the intake passage inlet 111a.
12 is located. The air cleaner body 116 is integrally formed with a cleaner side intake passage pipe portion 123 extending to the cylinder head side by resin.
3 is an air cleaner mounting surface 11 by a bolt (not shown)
4, the intake passage 111 of the cylinder head 7 is fixed.
Is connected to the entrance 111a. Air cleaner body 11
A fresh air suction pipe 120 is provided on the cylinder head side surface of 6,
The resin is integrally formed with the air cleaner body 116.

The air cleaner lid 117 has a mounting bolt 1
24 and the wing nut 125, the air cleaner body 116
It is detachably attached to the air cleaner lid 11
An element 121 is mounted in the inside 7.

In FIG. 12 showing the XII-XII cross section of FIG. 1, the fresh air suction pipe 120 of the air cleaner 9 is formed in an L-shape, and from the fresh air intake port 120a on the rear surface at the upper end to the intake passage pipe portion 123. Extending substantially horizontally to the front side and bent downward at the end on the front side.
20b communicates with the outer space portion 128 of the element 121 as shown in FIG.

In FIG. 11, the element 121 is formed in a rectangular frame shape, and the inner space portion 129 is the intake passage pipe portion 12.
It communicates with 3. Reference numeral 130 is a bolt hole for inserting the element body mounting bolt. During engine operation, the fresh air sucked from the fresh air intake 120a of FIG. 12 enters the element outer space portion 128 of FIG. 11 from the suction pipe 120, passes through the element 121, is cleaned, and enters the internal space 129. Then, the intake passage 1 of the cylinder head 7 is passed through the intake passage pipe portion 123 on the air cleaner side.
Enter 11.

[0030]

[Second Embodiment] FIG. 13 shows an internal combustion engine to which the inventions of claims 1 and 2 are applied, showing a single package in which the engine is wrapped with a soundproof cover 57, and a fan case mounting surface 53 of the engine body and a fan. A partition plate 58 is sandwiched between the cases 18,
The inside of the soundproof cover 57 is located on the power take-out side of the partition plate 58.
It is divided into a room 73 and a second room 74 on the fan case side. An engine body, an exhaust muffler 10 and an air cleaner 9 are arranged in the first chamber 73, and a fan case 18 and a fuel tank 19 thereabove are arranged in the second chamber 74.
An exhaust duct 59 is connected to the exhaust flange 38,
The exhaust air from the cylinder 2 and the cylinder head 7 is collectively guided into the exhaust muffler cover 59a and is exhausted to the outside of the soundproof cover 57. The primary expansion chamber / exhaust pipe 41 is housed in the exhaust duct 59.

The first chamber 73 dissipates heat from the engine body and the exhaust pipe 4
The second chamber 74, which is heated by the exhaust air of 1 and the cooling air, and is partitioned by the partition plate 58, is kept at a low temperature room. The air intake 9a of the air cleaner 9 penetrates through the partition plate 58 and opens in the second chamber 74 having a low temperature, so that cold fresh air can always be easily taken in, which is useful for improving the output.

[0032]

[Third Embodiment] FIG. 14 shows an internal combustion engine to which the invention of claims 1 and 2 is applied, which is mounted on a soundproof work machine such as a generator set. It is equipped with a generator (not shown) and an internal combustion engine.

A partition plate 58 is sandwiched between the fan case mounting surface 53 of the engine body and the fan case 18, and the soundproof cover 5 is attached.
The inside of 7 is divided into a first chamber 73 on the power take-out side of the partition plate 58 and a second chamber 74 on the fan case side. First room 7
3 is an engine main body, and a large horizontal exhaust muffler 1
0, the air cleaner 9, the working machine, the fuel tank 18 and the like are arranged, and the fan case 18 is arranged in the second chamber 74. An exhaust duct 59 is connected to the exhaust flange 38, and the exhaust air from the cylinder 2 and the cylinder head 7 is collectively guided into the exhaust muffler cover 59a, and the soundproof cover 5 is attached.
It is designed to be discharged to the outside of 7. The primary expansion chamber / exhaust pipe 41 is housed in the exhaust duct 59.

The first chamber 73 is the heat of the engine body and the exhaust pipe 41.
Also, the second room 74, which is heated by the cooling exhaust air and is partitioned by the partition plate 58, is kept at a low temperature room. The air intake 9a of the air cleaner 9 has a partition plate 58.
The second room 74, which has a low temperature, is pierced through, and cold fresh air can always be taken in easily, which helps to improve the output.

[0035]

As described above, according to the invention described in claim 1 of the present application, the cooling exhaust air from the cylinder head 7 and the cylinder 2 is gathered in one place, and the exhaust air flange 38 surrounding them is formed. By doing so, the exhaust duct or the like can be easily attached when the device is mounted on the working machine, and the exhaust air can be easily treated. As a result, noise reduction and simplification of the structure of the working machine set can be achieved.

Further, the temperature of the inside of the working machine can be kept low by collecting the cooling exhaust air in one place and letting it out of the working machine.

According to the second aspect of the present invention, since the fuel injection valve 43 is housed in the fuel injection valve chamber 46 of the cylinder head cover 8, the noise emitted from around the nozzle can be blocked.

Further, since a part of the cooling air of the cylinder head 7 is guided to the fuel injection valve chamber 46 to actively cool the fuel injection valve 43, the temperature rise of the fuel injection valve 43 can be effectively suppressed. You can

[Brief description of drawings]

FIG. 1 is a front view of an air-cooled internal combustion engine to which the inventions of claims 1 and 2 are applied.

FIG. 2 is a front view of FIG.

FIG. 3 is a rear view of FIG.

FIG. 4 is a right side view of FIG. 1.

FIG. 5 is a horizontal sectional view of a cylinder head.

FIG. 6 is a vertical sectional view of a cylinder head cover.

7 is a sectional view taken along line VII-VII of FIG.

FIG. 8 is an enlarged vertical sectional view of an upper mounting portion of the fuel tank.

FIG. 9 is a vertical sectional view of a lower mounting portion of the fan case.

FIG. 10 is a vertical cross-sectional view of a cooling fan.

11 is a cross-sectional view taken along the line XI-XI of the air cleaner shown in FIG.

12 is a cross-sectional view taken along the line XII-XII of the air cleaner shown in FIG.

FIG. 13 is a schematic horizontal cross-sectional view of a single package of an internal combustion engine including an exhaust duct and a partition plate.

FIG. 14 is a schematic horizontal cross-sectional view of a working machine set including an exhaust duct and a partition plate.

[Explanation of symbols]

 1 ... Cylinder block 2 ... Cylinder 7 ... Cylinder head 8 ... Cylinder head cover 9 ... Air cleaner 10 ... Exhaust muffler 12 ... Crank shaft 13 ... Balancer shaft 14 ... Cam shaft 17 ... Cooling fan 18 ... Fan case 29 ... Cell motor 32 ... Cylinder side cooling Air passage 33 ... Head side cooling air passage 34 ... Exhaust port 38 ... Exhaust air flange 41 ... Primary expansion chamber / exhaust pipe 42 ... Exhaust air guide 43 ... Fuel injection valve 46 ... Fuel injection valve chamber 53 ... Fan case mounting surface 58 … Partition boards

Claims (2)

[Claims] 1. A cooling fan and a fan case are provided on the side opposite to the power take-off side, and a cooling air passage for passing cooling air from the cooling fan side to the power take-off side is formed in the cylinder head, and the cooling fan is provided in the cylinder. Side to form the cooling air passage for passing the cooling air from the power take-out side to the cooling air outlet on the power take-out side of the cylinder head and the cylinder, and forming an exhaust air flange surrounding them together, and exhausting air to the exhaust air flange. An air-cooled internal combustion engine characterized in that a duct, an exhaust guide, or the like is removable. 2. A cooling air passage for passing cooling air from the cooling fan side to the power take-out side is formed in the cylinder head,
A fuel injection valve chamber, which is separated from the rocker arm chamber, is integrally formed in the cylinder head cover fixed to the upper side of the cylinder head, and the end of the fuel injection valve chamber on the cooling fan side is cooled by the upper wall of the cylinder head. It communicates with the upstream side of the head side cooling air passage through the air intake hole, and the end of the fuel injection valve chamber on the power take-out side is connected to the head side cooling air passage through the cooling air outlet hole of the cylinder head upper wall. An air-cooled internal combustion engine characterized by communicating with a downstream portion.