JP2531563Y2 - Cooling system for overhead valve engine with suction cooling fan - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a cooling device for an overhead valve engine with a suction-type cooling fan, which effectively lowers intake and exhaust temperatures to improve charging efficiency and exhaust valves. To provide a device capable of preventing abrasion of a seat and the like.

<Prior art> Generally, in an overhead valve engine, in order to form an intake port and an exhaust port from a center portion to an outside in a cylinder head, cooling air is passed through a narrow portion between the intake and exhaust valves,
The cooling performance is improved.

That is, the basic structure of the cooling device of the overhead valve engine with the suction type cooling fan which is the object of the present invention is that the suction type cooling fan 1 is arranged in front of the overhead valve engine E as shown in FIGS. And the intake port 3 is connected to the cylinder head 2 of the engine E.
And an exhaust port 4 are formed, and an inlet 6 of the cooling air guide path 5 is opened near the rear of the cylinder head 2 so that the cylinder head 2
The outlet 7 of the cooling air guide passage 5 is opened at a portion facing the cooling fan 1 and the inlet 6 of the cooling air guide passage 5 is communicated with the outlet 7 through the portion 8 between the intake and exhaust valves.

As a prior art of this type, there is an actual fairness 1 shown in FIG.
As shown in JP-41861-A, the intake / exhaust ports 3.4 are arranged approximately front and rear in the cylinder head 2 and the inlet 6 of the cooling air guide path 5 is opened in the rear left side 2c of the cylinder head 2. The guide path 5 is bifurcated at the upper side 8a of the air intake / exhaust valve portion 8 at the upper side of the ventilation, and 5a is formed toward the front right side 2a of the cylinder head 2 through the air intake / exhaust valve portion 8. The other side 5b is formed toward the front left side 2b of the cylinder head 2 without passing through the section 8 between the intake and exhaust valves, and the cooling air is blown from the rear left side 2c to the front right side of the cylinder head 2.
In some cases, the guide is guided obliquely in the vertical direction toward 2a, and only the leftward portion of the cylinder head 2 is guided.

In the above-mentioned conventional technique, the cooling air guide path 5 is branched into two branches (in other words, two guide paths 5a and 5b are provided) so that a part of the cooling air does not pass through the portion 8 between the intake and exhaust valves. An attempt is made to improve the cooling performance of the cylinder head by reducing the suction resistance.

<Problem to be solved by the invention> However, in the above-described conventional technology, the cooling air flows only obliquely to the left and right or the front and rear direction to the left with respect to the intake and exhaust ports 3 and 4 arranged in front and rear. Insufficient cooling of the intake / exhaust ports 3 and 4 may increase the exhaust temperature and wear the exhaust valve seats, and may promote deterioration of the lubricating oil.

Further, there is a possibility that the intake air temperature increases and the output of the engine E decreases.

It is a technical object of the present invention to efficiently cool an intake / exhaust port.

<Means for Solving the Problems> Means for achieving the above problems will be described below with reference to the drawings showing the embodiments.

That is, according to the present invention, the suction type cooling fan 1 is disposed in front of the overhead valve engine, the intake port 3 and the exhaust port 4 are formed in the cylinder head 2 of the engine E, and the rearward portion of the cylinder head 2 is provided. An opening 6 of the cooling air guide passage 5 is opened, and an outlet 7 of the cooling air guide passage 5 is opened at a portion of the cylinder head 2 facing the cooling fan, and the inlet 6 is connected to the outlet 7 through a portion 8 between the intake and exhaust valves. In a cooling device for an overhead valve engine with a suction-type cooling fan, which is connected to the suction-type cooling fan, a portion 8 between the inlet 6 of the cooling air guide path 5 and the intake / exhaust valve 8 is provided.
Between the intake port 3 and the exhaust port 4 which are substantially parallel to each other, the suction / exhaust port 3 of the inner wall 11 of the inter-valve introduction side passage 10. The wall surface facing 4 is defined as a port side wall surface 12,
The wall surface near the combustion chamber of the engine E is defined as the combustion chamber side wall surface 13, and the air-cooling fins 14 are projected from the port side wall surface 12 toward the space in the inter-valve introduction side passage portion 10. It is characterized in that it is inclined in the passage direction of the inter-introduction passage section 10 and closer to the combustion chamber side wall surface 13 as it approaches the intake / exhaust valve section 8.

According to a second aspect of the present invention, there is provided a cooling device for an overhead valve engine with a suction type cooling fan according to the first aspect, wherein a central portion of the inter-valve introduction side passage portion 10 in the passage crossing direction toward the inlet is provided. The guide plate 15 is formed in a longitudinal section along the direction of the passage.

<Operation> (1) In the invention according to claim 1, the inter-valve introduction side passage portion 10 extending from the inlet 6 of the cooling air guide path 5 to the intake / exhaust valve portion 8 is connected to the substantially parallel intake port 3. It is formed between the exhaust port 4 and an inter-valve introduction side passage portion from the port side wall surface 12.
Since the air-cooling fins 14 project toward the space inside the cooling air 10, the cooling air passing through the cooling air guide path 5 comes into contact with the port side wall surface 12 facing the intake / exhaust ports 3 and 4 to release the heat from the air-cooling fins 14. Promotes and further cools intake and exhaust. Further, since the air-cooling fins 14 are inclined in the passage direction of the inter-valve introduction side passage portion 10 and closer to the combustion chamber side wall surface 13 as the air-inlet fins 14 approach the inter-intake / exhaust valve portion 8, cooling is performed. The cooling air flowing through the wind guide path 5 is strongly blown to the combustion chamber side wall surface 13 near the combustion chamber, which tends to generate high heat, and cools the combustion chamber side wall surface 13 efficiently.

(2) In the cooling device of the overhead valve engine with the suction-type cooling fan according to the first aspect of the present invention, in the cooling device for the overhead valve engine with the suction type cooling fan, the central portion of the inter-valve introduction side passage portion 10 in the transverse direction of the passage is directed toward the inlet. Since the guide plate 15 is formed in a longitudinal shape along the direction of the passage, the cooling air is smoothly guided to the air-cooling fins 14 by the direction guide plate 15 to promote the operation of the above (1).

<Effects of the Invention> (1) In the invention according to the first aspect, cooling passing through the cooling air guide passage contacts the port side wall surface facing the intake / exhaust port to promote heat radiation from the air-cooling fins, so that the intake air and the intake Since the exhaust gas is further cooled, the exhaust gas temperature can be reduced to prevent wear of the exhaust valve seat and the deterioration of the lubricating oil, and the intake air temperature can be reduced to increase the charging efficiency of the intake air, thereby improving the engine output. In addition, the cooling air flowing through the cooling air guide passage efficiently cools the side wall surface of the combustion chamber near the combustion chamber where the heat is particularly likely to be high due to the air-cooling fins.

(2) According to the second aspect of the present invention, since the cooling air is smoothly guided to the air-cooling fins by the direction guide plate, the effect of the above (1) can be further promoted.

<Example> Hereinafter, an example of the present invention will be described with reference to the drawings.

1 is a cross-sectional plan view of a cylinder head of a vertical overhead valve diesel engine with a suction-type cooling fan, FIG. 2 is a sectional view taken along line AA of FIG. 1, and FIG. 3 is a line BB of FIG. FIG. 4 is a schematic left side view of the engine, in which a cylinder head 2 and a head cover 20 are sequentially assembled above a cylinder 19 of a vertical overhead valve diesel engine E.

As shown in FIG. 4, the flywheel 16 and the suction-type cooling fan 1 are fixed in order in front of the crankshaft 17 of the engine E, Cooling air is sucked in from the suction port 21 facing the head cover 20 of the rear and the wind guide case 18, and is blown out from the outlet 22 of the wind guide case 18.

As shown in FIG. 1, an exhaust port 4 is formed in the cylinder head 2 from the center to the outside of the rear wall 25, and an intake port 3 is formed from the center to the outside of the right side wall 26.

Only one cooling air guide passage 5 is formed in the cylinder head 2, the inlet 6 of the guide passage 5 is opened near the rear of the right side wall 26 of the cylinder head 2, and the outlet 7 of the guide passage 5 is cooled by the cylinder head 2. The front side wall 27 facing the fan 1 is opened over substantially the entire surface.

The inlet 6 of the guideway 5 communicates with the outlet 7 through the intake / exhaust valve section 8 and the inlet / exhaust valve section 8
Is formed between the intake port 3 and the exhaust port 4 which are substantially parallel to each other.

Reference numeral 23 denotes an injection port of the fuel injection nozzle, and reference numeral 24 denotes a cowling.

As shown in FIG. 1, the axis 30 of the exhaust valve is disposed eccentrically to the left by an angle α from an imaginary line 31 in the longitudinal direction passing through the axis 28 of the intake valve.

On the other hand, as shown in FIG.
Of the inner wall 11, the wall surface facing the intake / exhaust ports 3 and 4 is a port side wall surface 12, and the wall surface of the engine E near the combustion chamber is a combustion chamber wall surface 13.

In this case, as shown in FIGS. 1 and 3, the air-cooling fins 14 protrude from the port side wall surface 12 toward the space in the passage portion 10, and the air-cooling fins 14 are connected to the passage of the inter-valve introduction side passage portion 10. The direction is inclined so as to approach the combustion chamber side wall surface 13 as it approaches the inter-intake / exhaust valve portion 8.

As shown in FIG. 1 to FIG. 3, a direction guide plate is provided near the central entrance of the inter-valve introduction side passage portion 10 in the transverse direction of the passage.
15 is formed in a longitudinal section along the direction of the passage, and the direction guide plate 15 is formed in a forked shape toward the air cooling fins 14 on the left and right sides of the passage.

Therefore, the function of the overhead valve engine E with the suction cooling fan of the present embodiment will be described.

With the rotation of the cooling fan 1, cooling air is sucked in from the rear of the engine E to the front to cool the engine E by air.

In this case, the cooling air passing through the cooling air guide passage 5 of the cylinder head 2 flows along the intake / exhaust ports 3.4, and the contact area with the port side wall surface 12 increases. Exhaust air can be cooled strongly.

Therefore, it is possible to prevent the exhaust temperature from lowering, thereby preventing wear of the exhaust valve seat and deterioration of the lubricating oil.

Also, the intake air temperature goes down and the intake air filling efficiency goes up,
The output of the engine E is improved.

On the other hand, since the air cooling fins 14 protrude from the port side wall surface 12 of the cooling air guide path 5 and the cooling air is smoothly distributed to the left and right air cooling fins 14 by the bifurcated directional guide plate 15, Heat dissipation from the air cooling fins 14 is promoted,
Cool the intake and exhaust air further.

Further, since the air-cooling fins 14 are directed obliquely to the combustion chamber side wall 13, the cooling air flowing through the cooling air guide path 5 is strongly blown to the combustion chamber side wall 13, and particularly the combustion chamber side wall 13, which tends to become high in heat, Can be efficiently cooled.

[Brief description of the drawings]

1 to 4 show an embodiment of the present invention. FIG. 1 is a cross-sectional plan view of a cylinder head of a vertical overhead valve diesel engine with a suction cooling fan, and FIG. 2 is AA of FIG.
FIG. 3 is a sectional view taken along the line BB of FIG. 1, FIG. 4 is a schematic left side view of the engine, and FIG. 5 is a diagram corresponding to FIG. E ... overhead valve engine, 1 ... suction cooling fan,
2 ... Cylinder head, 3 ... Intake port, 4 ... Exhaust port, 5 ... Cooling air guideway, 6 ... Inlet of 5, 7 ...
5 outlet, 8 ... intake-exhaust valve section, 10 ... 5 valve introduction side passage, 11 ... 10 inner wall, 12 ... 11 port side wall, 13 ... 11 combustion chamber side Walls 13, 14 ... Air-cooled fins, 15
.... Direction guide plate.

Claims (2)

(57) [Scope of request for utility model registration] An intake type cooling fan is disposed in front of an overhead valve engine. An intake port and an exhaust port are formed in a cylinder head of an engine.
The opening 6 of the cooling air guide path 5 is opened near the rear, the outlet 7 of the cooling air guide path 5 is opened at a position facing the cooling fan 1 of the cylinder head 2, and the inlet 6 is passed through a section 8 between the intake and exhaust valves. In the cooling device for an overhead valve engine with a suction type cooling fan connected to the outlet 7, the inter-valve introduction side passage portion 10 extending from the inlet 6 of the cooling air guide path 5 to the intake / exhaust valve portion 8 is substantially parallel. A wall surface formed between the intake port 3 and the exhaust port 4 and facing the intake / exhaust ports 3 and 4 of the inner wall 11 of the inter-valve introduction side passage portion 10 is defined as a port side wall surface 12, The wall surface near the combustion chamber of the engine E is defined as the combustion chamber side wall surface 13, and the air-cooling fins 14 are projected from the port side wall surface 12 toward the space in the inter-valve introduction side passage portion 10. In the passage direction of the space introduction side passage portion 10 and at the portion 8 between the intake and exhaust valves. Brute more it was oriented inclined to approach the combustion chamber side walls 13, the cooling device of the suction type cooling fan with an overhead valve engine, characterized in that. 2. The device according to claim 1, wherein a direction guide plate 15 is formed in a central portion of the inter-valve introduction side passage portion 10 in the passage crossing direction, near the inlet, in a longitudinal section along the passage direction. Cooling system for overhead valve engine with suction cooling fan.