JP2003042034A - Upper structure of air-cooled engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such problems that, since a high-pressure pipe is laid from the upper center part of a cylinder head to a fuel injection pump on the side of a cylinder block, the length of the high-pressure pipe communicating the cylinder head with the fuel injection pump is increased, and not only the peripheral area of the cylinder head is complicated but also the displacement of timing such as delay of injection occurs, and a normal rotation cannot be provided or a pressure led to the fuel injection nozzle is lowered. SOLUTION: In the upper structure of an air-cooled engine 1, the high- pressure pipe 19 for communicating the fuel injection nozzle 30 with the fuel injection pump 12 is disposed in a space formed of a bonnet 7, a fuel tank 9, and the cylinder head 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique in which a fuel injection pump, a fuel injection nozzle and the like of an air-cooled diesel engine are compactly arranged on the upper part of an engine and efficient cooling is possible.

[0002]

2. Description of the Related Art In a conventional diesel engine, a fuel injection nozzle is generally mounted on a cylinder head so as to extend upward so that fuel is injected toward the center of the cylinder. Further, in the fuel injection pump, the plunger is reciprocally driven by the rotation of the cam provided on the cam shaft. A high pressure pipe is connected between the fuel injection pump and the fuel injection nozzle so that fuel can be supplied.

[0003]

Since the fuel injection pump is driven by the cam shaft as described above, it is generally arranged on the side of the cylinder block so as to be arranged in the vicinity of the cam shaft. is there. On the other hand, since the fuel injection nozzle is arranged at the center of the cylinder head in a substantially vertical direction, the high pressure pipe connecting the two is inevitably long in order to pipe the high pressure pipe from above the center of the cylinder head to the side of the cylinder block. If this high-pressure pipe becomes long, not only the cylinder head surrounding becomes complicated, but also timing deviation such as injection delay occurs, normal rotation cannot be obtained, and pressure when reaching the fuel injection nozzle decreases. However, there was a problem that the desired horsepower could not be obtained.

In the case of an air-cooled single-cylinder diesel engine, the fins are projected around the cylinder block for cooling, but the cooling air is not guided to the fuel injection pump or the fuel injection nozzle and is left open. Since it was usual to keep it in the state, the cooling performance of the engine was not sufficient.

Therefore, according to the present invention, the high-pressure pipe is shortened for compactness by devising the arrangement so that the fuel injection pump and the fuel injection nozzle can be arranged as close as possible, and the high-pressure pipe is arranged in the cylinder block and its vicinity. The fuel tank is designed to guide the cooling air to improve the cooling efficiency.

[0006]

The present invention employs the following means in order to solve the above problems. First, in the first aspect of the present invention, in the upper structure of the air-cooled engine, the high-pressure pipe that connects the fuel injection nozzle and the fuel injection pump is arranged in the space formed by the bonnet, the fuel tank, and the cylinder head.

According to the second aspect of the invention, the fuel injection pump is provided vertically between the push rod chambers accommodating the pair of push rods.

Further, according to the present invention, openings for cooling the fuel injection pump, the high pressure pipe and the fuel pipe are formed in the cylinder head and the cylinder block.

Further, in claim 4, the fuel tank is used as a cooling air guide.

According to a fifth aspect of the present invention, a cooling air guide portion is provided integrally with the cylinder head at the intake port of the cylinder head.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described with reference to the accompanying drawings. 1 is a front sectional view of an air-cooled diesel engine according to the present invention, FIG. 2 is a sectional view taken along the line XX in FIG. 1, FIG. 3 is a sectional view taken along the line YY in FIG. 1, and FIG. FIG. 5 is a partial sectional view of FIG.
Is a partial plan view of a lower part of the engine, FIG. 6 is a plan view of the bonnet part, FIG. 7 is a side view of the valve arm support part, and FIG.
Is a side sectional view of the upper part of the engine, FIG. 9 is a view showing the connection between the fuel tank, the feed pump, the filter and the fuel injection pump, FIG. 10 is a side view of the fuel tank, FIG. 11 is a plan view of the same, and FIG. 12 is a front view of the same. 13 is the same rear view, FIG. 14 is a side sectional view of the cylinder block, and FIG. 15 is FIG.
FIG. 16 is a view as seen from an arrow A in FIG.
FIG. 17 is a partial front sectional view of the cylinder block.

First, the overall structure of the engine according to the present invention will be described with reference to FIGS. 1 to 5. The engine 1 has a cylinder block 2 at the top of the main body and a crankcase 5 at the bottom,
A cylinder block 2 has a cylinder 2a formed in the vertical direction in the center to accommodate a piston 4, a crankshaft 3 is pivotally supported by a crankcase 5, and the piston 4 and the crankshaft 3 are connected by a connecting rod 17. There is. An upper portion of the cylinder block 2 is covered with a cylinder head 6, an upper portion of the cylinder head 6 is covered with a bonnet 7 to form a valve arm chamber, and a muffler 8 is provided on one side (left side) of the bonnet 7.
Is arranged, and the fuel tank 9 is arranged on the other side (right side).

A governor 11 is arranged in the crankcase 5 below the cylinder block 2, and a fuel injection pump 12 is arranged above it. The fuel injection pump 12
Via the gear 50 provided on the crankshaft 3 to the camshaft 13
Power is transmitted to the cam gear 51 provided above, and the cam shaft 1
A pump drive cam 14 provided on the front and rear center of 3 pushes and pulls the plunger of the fuel injection pump 12 to suck the fuel from the fuel tank 9 and to the fuel injection nozzle 30 through the high pressure pipe 19 at a predetermined timing. It supplies a predetermined amount of fuel. Regarding the fuel supply amount of the fuel injection pump 12, the stroke of the plunger is changed by rotating the control lever so that the fuel injection amount can be adjusted. The control lever is interlockingly connected to the governor 11, and the governor 11 is connected to the cam gear 51 via the lubricating oil pump drive gear 52 and the governor gear 5.
Power is transmitted to 3 so that it can operate.

The pump drive cam 1 for the cam shaft 13 is also provided.
An intake cam 21 and an exhaust cam 22 are provided on both sides of 4,
The intake push rod 2 is attached to the intake cam 21 and the exhaust cam 22.
3 and the lower end of the exhaust push rod 24 are in contact with each other. An intake push rod chamber 60 accommodating the intake push rod 23 and the exhaust push rod 24 and an exhaust push rod chamber 61 are arranged substantially vertically in the cylinder block 2
Further, the fuel injection pump chamber 62 is formed between the intake push rod chamber 60 and the exhaust push rod chamber 61 by being formed on the cylinder head 6 and the bonnet 7. The intake push rod 23, the exhaust push rod 24, and the fuel injection pump 12 are arranged substantially parallel to each other and extend in the vertical direction.

Then, as shown in FIG. 3, an intake push rod 23 guided and supported by the cylinder block 2.
Lubricating oil communication passages 63 and 64 are provided on both outer sides of the exhaust push rod 24 so that the lubricating oil does not collect in the valve arm chamber 65 and the like even if the engine 1 tilts, and the lubricating oil can escape into the crankcase 5. ing. That is, the lubricating oil communication passage 63 provided on the outer side of the intake push rod 23 has an opening formed in the vertical direction so that the upper portion communicates with the intake push rod chamber 60 and the lower portion communicates with the crank chamber in the crankcase 5. is doing. Further, the lubricating oil communication passage 64 provided on the outer side of the exhaust push rod 24 has an upper portion communicating with the exhaust push rod chamber 61 and a lower portion vertically communicating with the cam gear 51 of the crank chamber in the crankcase 5. The opening is formed in the direction.

Further, as shown in FIG. 3, the intake push rod chamber 60 and the exhaust push rod chamber 61 of the cylinder head 6 have constricted portions 66 and 67 in the upper and lower middle portions to simplify the manufacture. That is, the intake push rod chamber 60 and the exhaust push rod chamber 61 of the cylinder head 6 are gradually narrowed from the upper side so that the opening cross-section is the smallest in the middle of the vertical direction (the constricted portions 66 and 67), and the lower side is reduced. The width of the crank chamber is gradually narrowed, and when the cylinder head 6 is manufactured by die casting or the like, the mold can be easily removed to improve the productivity, and the middle of the passage is narrowed to reduce the crank chamber. The noise and the like generated from the valve arm chamber 65 are hard to be transmitted to the valve arm chamber 65.

In this way, the fuel injection pump 12 is arranged side by side between the intake push rod 23 and the exhaust push rod 24, and the intake push rod 23, the exhaust push rod 24 and the fuel injection pump 12 are substantially parallel in the vertical direction. By arranging them, it is possible to easily perform die cutting at the time of casting, and to have a compact arrangement, which is assembled from above and the assemblability is improved.

The upper ends of the intake push rod 23 and the exhaust push rod 24 are in contact with the lower ends of one side of the intake valve arm 25 and the exhaust valve arm 26, respectively.
The upper ends of the intake valve 27 and the exhaust valve 28 are in contact with the lower ends of the other side of the valve 6, respectively. The intake valve arm 25 and the exhaust valve arm 26 are housed in a valve arm chamber 65 in the bonnet 7, and the midpoints thereof are supported by support members 31, 31 fixedly mounted on the cylinder head 6. The support members 31, 31 are arranged on both front and rear sides of the fuel injection nozzle 30.

That is, since the intake valve arm 25 and the exhaust valve arm 26 are substantially symmetrical in the front-rear direction, the intake valve arm 25 will be explained. As shown in FIGS. It is configured like a letter, and the left and right sides are bolts 70.7
0 is inserted from above and screwed and fixed to the cylinder head 6. A pivot shaft 31a is provided so as to project from the left-right center of the support member 31 toward the center of the main body in the front-rear horizontal direction, and the left-right center of the intake valve arm 25 is rotatably supported by the pivot shaft 31a. It is arranged so that it can be swung like a seesaw. The head bolt 71 penetrates the cylinder head 6 below the pivot 31a so that the cylinder block 2
It is fixed by screwing on.

In this way, the intake valve arm 25 and the exhaust valve arm 26 are cantilevered by the pivot members 31, 31, so that the intake valve arm 25 and the exhaust valve arm 26 are supported from both front and rear sides.
The intake valve arm 25 and the exhaust valve arm 26 can be arranged closer to the center of the cylinder so that they can be compactly arranged in the valve arm chamber 65. The space above the head bolt 71 for fixing the cylinder head 6 is also effectively used.

As shown in FIGS. 2 and 3, the intake valve 27
And the exhaust valve 28 are disposed above the piston 4, and the valve head 27a (28a) is seated on the valve seat formed on the lower surface of the cylinder head 6, and the cylinder 2a formed on the cylinder block 2 and the intake air formed on the cylinder head 6. It is arranged between the ports 6a (exhaust ports 6b). The intake port 6a communicates with an air cleaner, and the exhaust port 6b
Is communicated with the muffler 8 via the exhaust manifold 72. The valve rod 27b (28b) penetrates the cylinder block 6 upward and projects into the bonnet 7, and the spring 32 is externally fitted inside the bonnet 7 so that the intake valve 27 (exhaust valve 28) slides upward. Bias the intake valve 27
The (exhaust valve 28) is closed.

As shown in FIGS. 1, 4 and 6, the tip of the fuel injection nozzle 30 (discharging) is located above the center of the cylinder 2a and is separated by the bonnet 7 between the intake valve 27 and the exhaust valve 28. Part) is inserted so that fuel can be injected into the cylinder 2a.
0 indicates the fuel injection pump 1 from the vertical direction on the cylinder head 6.
It is arranged to be inclined to the 2 side. The fuel injection nozzle 30
Is supported and fixed by a supporting member 39 fixed to the cylinder head 6, and the fuel injection pump 12 and the fuel injection nozzle 30 are
Are disposed on the front and rear centerlines, and the fuel injection nozzle 30
Fuel intake port 30a of the fuel injection pump 1 of the nozzle body
It is arranged so as to protrude from the side surface on the second side so that the distance between the fuel injection pump 12 and the fuel injection nozzle 30 is as short as possible.

In other words, the fuel injection pump 12 and the fuel injection nozzle 30 are arranged as close to each other as possible, so that the arrangement can be made compact and the high pressure for connecting the fuel injection pump 12 and the fuel injection nozzle 30 to each other. The pipe 19 can be configured to be short, the fuel supply path can be shortened, injection delay and the like can be eliminated, and the loss can be reduced and the fuel pressure pumped from the fuel injection pump 12 can be kept high while the fuel is injected from the fuel injection nozzle 30. It can be jetted.

Further, the bonnet 7 covering the intake valve 27, the exhaust valve 28, the intake valve arm 25, the exhaust valve arm 26, etc. is formed in a concave shape in plan view, and the fuel injection nozzle 30 is arranged in the central concave portion 7a. In a plan view, in a closed space surrounded by the bonnet 7 and the fuel tank 9, in a front view,
The fuel injection pump 12, the high pressure pipe 19 and the fuel injection nozzle 30 are arranged in a space surrounded by the bonnet 7, the cylinder head 6 and the fuel tank 9.

Next, the structure for supplying fuel to the fuel injection pump 12 will be described. A fuel tank 9 is arranged in the upper right portion of the engine body, a fuel outlet 9a is provided in the lower portion of the fuel tank 9, and a hose 73 is connected to the fuel outlet 9a to communicate with the suction portion 15a of the feed pump 15. The discharge portion 15b of the feed pump 15 has a hose 74
Through the suction portion 16a of the filter 16.
The discharge portion 16b of the filter 16 is connected to the suction portion 12a of the fuel injection pump 12 via a hose 75. The discharge portion 12b of the fuel injection pump 12 is communicated with the fuel injection nozzle 30 via a high pressure pipe 19. The surplus port 16c provided in the filter 16 and the surplus port 12c provided in the fuel injection pump 12 are connected to the return port 9b provided in the upper portion of the fuel tank 9 via the surplus fuel hose 76, and the surplus fuel is supplied to the fuel tank. 9 It is configured to return to the upper part.

The feed pump 15 is composed of a diaphragm type pump.
The back chamber of the diaphragm is communicated with the pulse introduction port 15c for driving the hose 7 to the pulse introduction port 15c.
It is communicated with the crank chamber of the engine 1 via 7.
In the crank chamber, the piston 4 reciprocates to generate a pulsed negative pressure, and the pulsed negative pressure is used to vibrate the diaphragm to supply fuel through the valve. In order to take out this negative pressure, as shown in FIG. 3, an outlet 80 is provided on the side surface of the governor gear case 79 fixedly mounted on the side surface of the crankcase 5,
The hose 77 communicates with the outlet 80.

By providing the take-out port 80 in the governor gear case 79 as described above, there is no need to perform processing such as drilling holes in the cylinder block 2 and the crank case 5, and the governor gear case 79 having a different structure can be used in an engine of another specification. By making it possible to use it in common, it is possible to reduce the types of parts and costs.

Next, the construction of the fuel tank 9 and the arrangement of the feed pump 15 and the filter 16 are shown in FIGS.
3 will be described. The fuel tank 9 is configured to be long in the front-rear direction so as to substantially match the width of the engine 1 in the front-rear direction, and the tank is configured by combining the upper and lower casings. A refueling port 90 is provided in the front-rear central portion, the lid 91 closes the same, and a gauge 92 is provided on the front upper surface. A U-shaped recess 93 in a plan view is provided on the upper surface of the tank around the fuel filler port 90, and the bottom surface of the recess is lowered toward the right side so that when the fuel overflows, the outside (right side) I am trying to run down. The periphery of the recess 93 is configured to be high as a guard portion, and the return port 9b is provided on the upper side surface of the guard portion on the main body side to return to the high position. An edge is formed around the divided surface of the fuel tank 9, and a bulged portion is provided on the main body side, and mounting holes 94 are provided in that portion, and projecting pieces 95 95 are provided below the lower end. Is provided so that it can be fixed to the engine body.

A lower portion of the fuel tank 9 has a middle concave portion 97 and a rear concave portion 98 which are continuously formed on a side surface on the body side (left side). The middle concave portion 97 is provided with a cooling air guide and a fuel injection pump 12 as described later. The structure also serves as a cover. The rear recess 98 is arranged so as to house the feed pump 15. The rear recess 98 forms a wall of the fuel tank on the right side surface and the rear surface to increase the capacity, and
It also has a configuration that doubles as a cover. In this way, the feed pump 15 can be compactly arranged near the fuel tank 9.

As shown in FIG. 2, the filter 16 is arranged below the feed pump 15 and the fuel injection pump 12. In this way, the tank capacity is increased without providing a recess in the front portion of the fuel tank 9, and the suction portion 15a of the feed pump 15 is arranged below the lower end of the fuel tank 9 to facilitate suction. The fuel discharged from the feed pump 15 is sent to the filter 16 through the hose 74, dust and the like are removed by the filter 16, and the filter 16 is deflated. The fuel discharged from the filter 16 is sent to the fuel injection pump 12. Further, as shown in FIGS. 10, 11 and 12, the filter 16 may be provided with a front concave portion 96 in the front portion of the fuel tank 9 and arranged so as to house the filter 16 in the concave portion 96. With this configuration, the fuel tank 9 can be compactly arranged so as to cover the filter 16.

Next, the fuel from the filter 16 and
A structure for cooling the fuel supply passage from the fuel injection pump 12 to the fuel injection nozzle 30, the periphery of the cylinder head 6, and the like will be described. As shown in FIGS. 8 and 14 to 17, the intake port 6a is formed by forming a part of the cylinder head 6 into a pipe shape to integrally form a conventional intake pipe, and is connected to the air cleaner 20 at the tip. With this configuration, the conventional intake pipe is omitted to achieve compactness and cost reduction.
The cooling air guide portion 33 is provided below the intake port 6a.
Is formed, and the cooling air from the cooling fan 34 is guided to the cylinder head 6 side for cooling. That is, as indicated by an arrow a shown in FIG. 15, the cooling air from the cooling fan 34 is linked through the periphery of the cylinder head supporting the intake valve 27 and the exhaust valve 28. The cooling fan 34 is fixed to the crankshaft 3, is disposed on the side opposite to the output side, is disposed between the flywheel 35 and the pulley 36 around which the starting rope is wound, and is covered by the fan case 37. .

In order to cool the fuel injection pump 12, the high-pressure pipe 19, the fuel pipe hose, the cylinder 2a, etc.,
As shown in FIGS. 1 and 17, an opening is provided in the front-rear direction so that cooling air can escape, and cooling air passages 40a and 40b are provided in the cylinder block 2 to cool the fuel injection pump 12 and the cylinder 2a. The cylinder head 6 is provided with cooling air passages 41a, 41b, 41c, 41d, 41e to cool the intake valve 27, the exhaust valve 28, the fuel injection nozzle 30, the cylinder head 6 and the like.

Further, a cooling air guide is also formed inside the fuel tank 9 so that the cooling air from the cooling fan 34 does not escape and is efficiently applied to the cylinder block 6 for cooling. That is, the fuel tank 9 is disposed so as to cover the upper right portion of the engine 1 main body, and the fan case 3
It extends from the upper part of 7 via the side part of the cylinder head 6 to the front. Then, a space is formed between the side surface of the fuel tank 9 on the engine body side and the cylinder block 2 to form a space to form a middle recess 97. The middle recess 97 is formed in the outer peripheral shape of the cylinder block 2 and the cylinder head 6. With the combined shape, the cooling air passes through the space to cool the cylinder block 2 and the cylinder head 6.

[0034]

Since the present invention is configured as described above, it has the following effects. First, as in claim 1, in the upper structure of the air-cooled engine, the high-pressure pipe that connects the fuel injection nozzle and the fuel injection pump is arranged in the space formed by the bonnet, the fuel tank, and the cylinder head. The distance of the fuel injection pump can be shortened, and it has become possible to make it compact. Also, the high-pressure pipe can be configured as short as possible, the pressure from the high-pressure pipe to the fuel injection nozzle can be maintained high, the injection delay can be eliminated, the fuel can be stably supplied, and the stable rotation can be achieved. Can also be obtained.

Since the fuel injection pump is arranged vertically between the push rod chambers accommodating the pair of push rods, the arrangement holes can be arranged vertically. As a result, the castability and workability of the cylinder head, the cylinder block and the like can be improved, the cost can be reduced, and the ease of assembling the fuel injection pump into the cylinder can be improved.

Further, since the openings for cooling the fuel injection pump, the high pressure pipe and the fuel pipe are formed in the cylinder head and the cylinder block as in claim 3, not only the cylinder block and the cylinder head but also the fuel injection pump. It was possible to improve the cooling performance of the injection system such as the high pressure pipe and the fuel supply hose. As a result, the engine performance can be improved.

Since the fuel tank is a cooling air guide, it is not necessary to separately provide a guide for cooling, the number of parts can be reduced, the cooling performance can be improved, and the fuel tank itself can be used. Can also be cooled.

Further, as described in claim 5, since the cooling air guide portion is provided integrally with the cylinder head at the intake port of the cylinder head, the intake pipe which is conventionally provided as a separate body can be eliminated, Cost can be reduced by reducing the number of parts. Further, it is possible to reduce the cost because it is not necessary to separately provide a cooling air guide.

[Brief description of drawings]

FIG. 1 is a front sectional view of an air-cooled diesel engine according to the present invention.

FIG. 2 is a sectional view taken along line XX in FIG.

3 is a cross-sectional view taken along the line YY in FIG.

FIG. 4 is a partial cross-sectional view of an upper plan view of the engine.

FIG. 5 is a partial plan view of a lower plan view of the engine.

FIG. 6 is a plan sectional view of a bonnet portion.

FIG. 7 is a side sectional view of a valve arm support portion.

FIG. 8 is a side sectional view of the upper part of the engine.

FIG. 9 is a diagram showing a connection between a fuel tank, a feed pump, a filter, and a fuel injection pump.

FIG. 10 is a side view of the fuel tank.

FIG. 11 is a plan view of the same.

FIG. 12 is a front view of the same.

FIG. 13 is a rear view of the same.

FIG. 14 is a side sectional view of a cylinder block.

15 is a view on arrow A in FIG.

16 is a view on arrow B in FIG.

FIG. 17 is a partial front sectional view of a cylinder block.

[Explanation of symbols]

1 engine 2 cylinder block 6 cylinder head 7 Bonnet 9 Fuel tank 12 Fuel injection pump 19 high-pressure pipe 30 Fuel injection nozzle

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02B 67/00 F02B 67/00 C F02F 1/04 F02F 1/04 1/32 1/32 1/34 1 / 34 7/00 7/00 N F02M 37/00 301 F02M 37/00 301D 55/02 350 55/02 350G (72) Inventor Junichi Funayama 1-32 Chayacho, Kita-ku, Osaka-shi, Yanma Diesel Co., Ltd. F term (reference) 3G024 AA01 AA09 AA21 BA00 BA29 CA19 DA02 DA08 DA16 FA00 3G066 AA07 AC01 AD05 BA41 CD23

Claims (5)

[Claims] 1. An upper structure of an air-cooled engine, characterized in that a high-pressure pipe communicating a fuel injection nozzle and a fuel injection pump is arranged in a space formed by a bonnet, a fuel tank and a cylinder head. Construction. 2. The upper structure of the air-cooled engine according to claim 1, wherein the fuel injection pump is provided in a vertical direction between push rod chambers accommodating a pair of push rods. 3. The upper structure of the air-cooled engine according to claim 1, wherein openings for cooling the fuel injection pump, the high pressure pipe and the fuel pipe are formed in the cylinder head and the cylinder block. 4. The upper structure of the air-cooled engine according to claim 1, wherein the fuel tank is a cooling air guide. 5. The upper structure of the air-cooled engine according to claim 1, wherein a cooling air guide portion is integrally provided with the cylinder head at an intake port of the cylinder head.