JPH0351900B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a locally liquid-cooled air-cooled cylinder head for an internal combustion engine.

(Prior art) Conventionally, in an air-cooled cylinder lid, the annular passage surrounding the fuel injection valve and the coolant passage between the valves are arranged in a square shape with the fuel injection valve at the center, and the annular passage is divided into two parts. The coolant introduced into one of the annular passages from the intervalve passage is discharged from the second intervalve passage, the discharged coolant is introduced from the third intervalve passage into the other annular passage, and the coolant is introduced into the fourth intervalve passage. A locally liquid-cooled air-cooled cylinder lid that discharges liquid has already been proposed (for example, Publication of Utility Model Publication No. 39-15729). However, in that case, the circulation path for the coolant becomes complicated, and it is impossible to cool the entire circumference of the fuel injection valve that requires the most cooling at once with the cold coolant that is initially introduced. There is a risk of thermal distortion occurring.

(Object of the Invention) The present invention introduces cold coolant from the outside directly into the entire annular passage surrounding the fuel injection valve that requires the most cooling in the bottom wall of the cylinder head on the combustion side, and from there By diverting the flow through the intervalve passage, the cooling effect of the fuel injection valve part is enhanced,
Moreover, the purpose of this design was to make it possible to effectively cool the area between the valves with a simple structure, and to make it possible to cool the lubricating oil inside the bonnet with the coolant after passing through the bottom wall of the cylinder head on the combustion side. There is.

(Structure of the Invention) The present invention is a local liquid-cooled air-cooled head for an internal combustion engine as described in the claims, in which the cooling water is cooled directly by the entire cold cooling liquid in the vicinity of the nozzle 22 of the fuel injection valve 10. The coolant is then radially branched away from the annular passage through the intervalve passage, and the bottom wall of the cylinder head on the combustion side is cooled by low-temperature coolant in order from the fuel injection valve side, which has the highest temperature.
Furthermore, the cooling fluid continues to pass through the top wall of the cylinder head, cooling the lubricating oil inside the bonnet as well.

(Embodiment) FIG. 1 is a horizontal sectional view of a cylinder head 1, which corresponds to a cross section taken along the line - in FIG. 2, which shows the - cross section in FIG. 1, viewed from above. In FIG. 1, two intake ports 2 and 3 communicate with valve seats (not shown) that are opened and closed by intake valves 4 and 5, respectively, and an exhaust port 6 communicates with two exhaust valves 7 and 5, respectively.
It communicates with the exhaust valve seat which is opened and closed by 8. This cylinder head 1 is a member that is fastened to the lower cylinder block by a plurality of head bolts 9, and is equipped with a fuel injection valve 10 in the center of four intake and exhaust valves 4, 5, 7, 8, A cooling fluid introduction passage A, which will be described later, and intervalve cooling passages B, C, and D intersect in a criss-cross pattern around the injection valve 10.

Coolant introduction passage A in cylinder head bottom wall 1a
As shown in FIG. 3, one end is connected to the discharge port of the coolant pump via the coolant inlet pipe 11, and the left end is connected to the annular passage 12 surrounding the fuel injection valve 10, and the left end is connected to the annular passage 12 that surrounds the fuel injection valve 10. It is continuous with the valve cooling passage B. The tip of the passage B communicates with a second annular passage 13 surrounding the fuel injection valve 10 via a vertical passage E and a horizontal passage H. In FIG. 3, 14 is a fuel injection pipe, 15 is a fuel return pipe, 16 is an injection valve holder, and 17 is a fuel injection pipe.
is a screw-in plug, and 19 is an O-ring.

As shown in FIG. 2, the intervalve cooling passages C and D, which are divided into left and right sides from the annular passage 12, have vertical passages F,
Passage F and G are connected to cylinder head top wall 1.
It is continuous with the in-bonnet lubricating oil cooling passages I and J in b. The passage I is continuous with the annular passage 13. The middle part of the passage J is continuous with a vertical in-bonnet cooling passage K, and this passage K is connected to a coolant tank (not shown) via passages L, M, and a coolant outlet pipe 21 as shown in FIG. ing. In Figure 2, 2
2 is a nozzle, 23 is a nozzle sleeve, 24 is a bonnet, 25 is a bridge guide, and 26 is a valve bridge.

The coolant pressurized during engine operation flows through the inlet pipe 11.
(Fig. 3) reaches the annular passage 12 via the introduction passage A, and is branched from the annular passage 12 into passages B, C, and D, and the cooling liquid in passage B passes through passages E and H, and the cooling liquid in passage C The coolant enters the annular passage 13 through the passages F and I, and the coolant in the passage D passes through the passage G and enters the passage J. The coolant in the annular passage 13 also joins through the passage J, and then flows into the passage. The coolant is discharged from the coolant outlet pipe 21 via K, L, and M. During this time, the cooling fluid passing through the passages A, B, C, and D cools the intake and exhaust valves. Also, circular passage 1
The fuel injection valve is cooled by the coolant in 2 and 13. Also passages H, I, J, K, L and annular passage 1
3, the lubricating oil inside the bonnet is cooled.

(Effects of the Invention) According to the present invention, the coolant introduced from one location on the side of the combustion surface is divided into the annular passage 12 at the center of the cylinder, and after cooling the local part that requires cooling,
It joins the passage K on the anti-combustion surface side and is discharged to the outside of the cylinder head while cooling the lubricating oil inside the bonnet 24, so that the following special effects can be obtained. That is, fuel injection valve 1
Since the portion near the nozzle 22 of No. 0 is cooled first by the entire cold coolant introduced from the passage A, the cooling effect is enhanced. Moreover, since the coolant after cooling the parts of the fuel injection valve 10 that require cooling is divided radially through the intervalve passages B, C, and D so as to move away from the annular passage 12, the bottom wall 1a of the cylinder head on the combustion side is the most It is possible to cool the fuel injection valve side with a low temperature coolant in order from the high temperature fuel injection valve side, and at the same time, it is possible to effectively cool the area between the valves where the heat load is high. Furthermore, in the present invention, the coolant after cooling the fuel injection valve 10 and the area between the valves is passed through the passages H, I, J, K, L, M, 13, etc. in the cylinder head top wall 1b, and is then discharged into the bonnet 24. This has the advantage that deterioration of the lubricating oil in the bonnet 24 and thermal deformation of the cylinder head 1 can be reduced as much as possible by cooling the lubricating oil in the bonnet 24 and the cylinder head top wall 1b at the same time. Although air cooling is more advantageous in reducing cooling loss in an internal combustion engine, air cooling alone poses a problem of heat load on the cylinder head. However, according to the present invention, since the engine is of a local liquid cooling type, cooling loss can be kept to a minimum and engine performance can be improved.

[Brief explanation of drawings]

FIG. 1 is a horizontal sectional view, and FIGS. 2, 3, and 4 are -, -, and - sectional views of FIG. 1, respectively. DESCRIPTION OF SYMBOLS 1... Cylinder head, 1a... Cylinder head bottom wall on the combustion side side, 1b... Cylinder head top wall, 10... Fuel injection valve, 12... Annular passage, A... Coolant introduction passage, B, C, D... Valve cooling passage, G, F... Vertical passage, H, I, J,
L, M...Lubricating oil cooling passage inside the bonnet.

Claims (1)

[Claims] 1. A coolant introduction passage from the outside in the bottom wall of the cylinder head on the side of the combustion chamber that passes through the valve gap and leads to an annular passage surrounding the fuel injection valve, and a valve that branches from the annular passage and passes through the remaining valve gap. A vertical passage is provided in the side wall of the cylinder head that extends upward from the tip of the cooling passage between the valves, and a bonnet is provided in the top wall of the cylinder head that connects each vertical passage through the valve gap and communicates with the outside. An internal lubricating oil cooling passage is provided, and the in-bonnet lubricating oil cooling passage has another annular passage surrounding the fuel injection valve in the middle, and the introduction passage is located between the first intake valve and the first exhaust valve, and the in-bonnet lubricating oil cooling passage has an inter-valve cooling passage. A local liquid-cooled air-cooled head for an internal combustion engine, wherein a passage is provided between a second intake valve and a second exhaust valve, between the first and second intake valves, and between the first and second exhaust valves.