JP2553958B2 - Cylinder head device for forced air cooling engine - Google Patents

Description

TECHNICAL FIELD The present invention relates to a cylinder head device for a forced air cooling type engine.

[Prior Art] Conventionally, as a cylinder head device of a forced air cooling type engine, as shown in FIG. 3 (A), a cooling air passage is formed in a cylinder head 51, and an exhaust port pipe wall is provided in a cooling air passage 54.
There is a device in which the pipe wall intermediate portion 53 of 52 is faced in a crosswise manner, and gaps 56 and 57 for passage continuity are left above and below the pipe wall intermediate portion 53. In order to prevent the leaning portion 53 from becoming a throttle resistance of the exhaust gas, FIG. 3 (B)
・ As shown in (C), the vertical width 53a of the tube wall intermediate portion 53
And the vertical width 55a of the pipe wall end portion 55, and the lateral width 53b of the pipe wall middle portion 53 is set to the pipe wall end portion 55 side width 55b.
Therefore, the cross-sectional area of the passage in the tube wall intermediate portion 53 can be maintained at the same level as the cross-sectional area of the passage in the tube wall end portion 55.

[Problems to be Solved by the Invention] The above-mentioned conventional techniques have the following problems.

Cylinder head 51 to make the engine compact
When it is necessary to reduce the overall height of the pipe, as shown in FIG. 3 (A), the pipe wall intermediate portion 53 is relatively large. The area becomes small, the cooling performance of the exhaust port pipe wall 52 is low, and overheating thereof causes thermal strain in the entire cylinder head 51, causing cracks and gas leakage from the head gasket.

For casting the cylinder head 51, the passage continuity gaps 56 and 57 are used.
In order to form a hollow part such as a hollow core, a molding sand core is used to model the hollow part, but the gap 56/57 for passage continuity becomes narrower. The core part becomes thinner, and it is easy to damage it during casting.
It is also difficult to perform sand removal after casting from the narrow passage continuation gaps 56 and 57, which makes casting of the cylinder head 41 difficult.

An object of the present invention is to make it possible to secure a large passage cross-sectional area of a passage continuation gap while keeping the overall height of a cylinder head low.

[Means for Solving the Problem] As shown in FIG. 1 (A), the present invention forms a cooling air passage 4 in a cylinder head 1 and a pipe of an exhaust port pipe wall 2 in the cooling air passage 4. A cylinder head device for a forced air-cooled engine in which a wall-intermediate-portion 3 is transversely faced, and passage continuation gaps 6 and 7 are left above and below the pipe wall-intermediate portion 3, as shown in FIG. 1 (B). As shown in FIGS. 1 (C) and 1 (D), the pipe wall intermediate portion 3 of the exhaust port pipe wall 2 is formed in a horizontal flat shape that is long in the passage forming direction of the cooling air passage 4. The vertical width 3a of the tube wall middle part 3 is narrower than the vertical width 5a of the tube wall end part 5 and the lateral width 3b of the tube wall middle part 3 is wider than the lateral width 5b of the tube wall end part 5. It is a thing.

[Operation] The present invention operates as follows.

Even if the overall height of the cylinder head has to be reduced in order to make the engine compact, the first
As shown in FIGS. (C) and (D), the tube wall middle portion 3 is flattened to such an extent that the vertical width 3a thereof is narrower than the vertical width 5a of the tube wall terminal end portion 5; As shown in FIG. 6B, the passage cross-sectional area of the passage continuity gaps 6 and 7 can be increased.

Since the passage cross-sectional areas of the passage continuity gaps 6 and 7 can be made large, the core portion that models the passage continuity gaps 6 and 7 can be made thicker, which reduces the risk of breakage during casting and also reduces The sand removal can also be easily performed through the wide passage continuation gaps 6 and 7.

As shown in FIGS. 1 (C) and (D), the tube wall middle part 3 is flattened so that the lateral width 3b thereof is wider than the lateral width 5b of the tube wall end part 5 so that the tube wall is flattened. A passage cross-sectional area of a required size can be secured in the middle portion 3, and this does not serve as throttling resistance of exhaust gas, and there is no fear that the scavenging efficiency will decrease.

[Effect] The present invention has the following effects.

Even if the overall height of the cylinder head has to be made low in order to make the engine compact, the passage cross-sectional area of the passage continuity gap can be made large, so that the cooling performance of the exhaust port pipe wall is reduced. It is possible to prevent thermal distortion of the entire cylinder head due to the overheating, and to prevent cracks and gas leakage from the head gasket.

Because the passage cross-sectional area of the passage continuity gap can be made large, the core part that molds the passage continuity gap can be made thicker, and there is less risk of damage to this core during casting, and wide sand removal after casting is also possible. This can be easily performed through the continuous gap, and the cylinder head can be easily manufactured.

[Embodiment] An embodiment of the present invention will be described with reference to the drawings.

In FIG. 2, reference numeral 11 indicates a vertical in-line two-cylinder diesel engine.

The engine 11 is provided with front and rear cylinders 13 and 14 arranged side by side in the front-rear direction on the upper side of a crankcase 12, and the cylinder head 1 is assembled on the upper side of the front and rear cylinders 13 and 14 with a head gasket 15 interposed therebetween. A fan case 17 accommodating a cooling fan 16 is attached to the front side of the.

As shown in FIG. 1 (A), in the cylinder head 1, the front and rear cylinders 13
Oil cooling jacket that surrounds each of the 14 sub-combustion chambers 18 in series
19 are provided, and the front and rear cylinders 13 are provided along the front and rear walls 20 and 21.
The exhaust port pipe wall 2 forming the intake ports 22 and 23 of 14 sideways and forming the common exhaust port 24 of the front and rear cylinders 13 and 14 at the center of the front right and left direction of the head right half part of the oil cooling jacket 19 The front and rear tappet chambers 25 and 26 are formed at the right end of the head from the right side, and a series of cooling air passages 4 are formed in the front and rear direction along the front and rear tappet chambers 25 and 26.

The exhaust port pipe wall 2 comprises a bifurcated pipe wall start end portion 27, a pipe wall middle portion 3 and a pipe wall end portion 5 which are transverse to the cooling air passage 4. The pipe wall end-approximating portion 5 is formed between the front and rear tappet chambers 25 and 26.

The front end portion 31 of the cooling air passage 4 faces the fan case 17 (see FIG. 2), and the rear end portion 33 of the cooling air passage 4 is opened to the atmosphere, and as shown in FIG. Passage continuation gaps 6 and 7 are left above and below the wall middle portion 3 to allow the cooling air 34 to flow along the cooling air passage 4 from the front side to the rear side in the cylinder head 1.

As shown in FIGS. 1 (C) and 1 (D), the exhaust port pipe wall 2 has a pipe wall middle portion 3 and a pipe wall end portion 5 each having a lateral flat shape that is long in the passage forming direction of the cooling air passage 4. Although it is formed in a rectangular shape, the vertical width 3a of the pipe wall intermediate portion 3 of the exhaust port pipe wall 2 is narrower than the vertical width 5a of the pipe wall terminal portion 5 and the horizontal width 3b of the pipe wall intermediate portion 3 is It is formed wider than the lateral width 5b of the end portion 5 near the end of the tube wall.

As shown in FIG. 1 (B), a cooling air branch passage 35 that branches to the right from the lower passage continuity gap 7 is formed below the pipe wall end portion 5 and the pipe wall end portion 5 is also air-cooled. And as shown in FIG. 1 (A), the rear tappet chamber
From the empty wall of 26 into the cooling air passage 4, the intake port pipe wall 36 on the rear side
The cooling air deflecting wall 37 extending in the direction, and the cooling air 34 deflected by the cooling air deflecting wall 37 causes the rear intake port pipe wall 36
So that it can be air-cooled.

As shown in FIG. 2, the oil is supplied to the oil cooling jacket 19 through the relief valve 41 and the inter-cylinder jacket 42 in order by the oil 39 in the oil pan 38 by the pumping force of the oil pump 40. The oil is returned from the oil cooling jacket 19 to the oil pan 38 via the oil cooler 43.

As shown in FIG. 1 (A), a sand removal port 44 is opened on the left side of the oil cooling jacket 19 and is covered with a manifold pipe wall 46 of the intake manifold 45.

Further, a leakage oil cut-off groove 49 is provided in the flange facing portion 47 located between the oil cooling jacket 19 and the intake ports 22 and 23 so as to sandwich the gasket 48, and the oil 39 in the oil cooling jacket 19 faces the flange. The capillarity of the portion 47 prevents the permeation into the intake ports 22 and 23.

[Brief description of drawings]

FIG. 1 is a view for explaining a cylinder head device according to an embodiment of the present invention. FIG. 1 (A) is a cross-sectional plan view of the cylinder head device, and FIG. 1 (B) is a view of FIG. 1 (A). FIG. 1 (C) is a sectional view taken along line CC of FIG. 1 (B), and FIG. 1 (D) is a sectional view taken along line DD of FIG. 1 (B). . FIG. 2 is a vertical sectional side view of an engine in which a cylinder head device according to an embodiment of the present invention is assembled. FIG. 3 is a diagram for explaining the prior art, and FIG.
FIG. 3B is equivalent to FIG. 3B, and FIG. 3B is BB of FIG. 3A.
FIG. 3C is a sectional view taken along line CC of FIG. 3A. 1 ... Cylinder head, 2 ... Exhaust port pipe wall, 3 ...
2 pipe wall middle portion, 3a …… 3 vertical width, 3b …… 3 horizontal width, 4 …… cooling air passage, 5 …… 2 pipe wall end portion, 5a
…… 5 vertical width, 5b …… 5 horizontal width, 6.7 …… Gap for continuous passage.

Claims (1)

(57) [Claims] A cooling air passage (4) is formed in a cylinder head (1), and a pipe wall intermediate portion (3) of an exhaust port pipe wall (2) is made to face the cooling air passage (4) in a transverse manner. In a cylinder head device for a forced air-cooled engine, in which upper and lower passage gaps 6 and 7 are left, the pipe wall middle portion 3 of the exhaust port pipe wall 2 is formed in a horizontal flat shape that is long in the passage forming direction of the cooling air passage 4. However, the vertical width 3a of the pipe wall middle portion 3 of the exhaust port 2 is narrower than the vertical width 5a of the pipe wall end portion 5 and the horizontal width 3b of the pipe wall middle portion 3 is the horizontal width 5b of the pipe wall end portion 5. Cylinder head device for forced air-cooled engines characterized by being formed wider than