JPH0123663B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cylinder head for a vertical shaft internal combustion engine used in an outboard motor or the like.

Generally, the cylinder head of a water-cooled internal combustion engine is a cast product, and the core for forming the water jacket during casting is often quite small, making it extremely difficult to support it.

In addition, in vertical-shaft internal combustion engines, such as those used in outboard motors, where the crankshaft is arranged vertically, cooling water must be poured into the water jacket of the cylinder head from the bottom and extracted from the top. First, it is necessary to insert a thermostat into the water jacket at the top, and after cooling the exhaust gas by mixing the cooled water in the water jacket with the exhaust gas coming out of the exhaust passage, It is necessary to release it below the aircraft body.

SUMMARY OF THE INVENTION Accordingly, the present invention facilitates the casting of a cylinder head with a water jacket formed thereon in a vertical axis type internal combustion engine as described above, and also facilitates the retention of a thermostat inserted into the water jacket. The object of this invention is to provide a cylinder head that can easily have a passage for water to flow through and out.

That is, in an internal combustion engine in which the crankshaft is disposed vertically, the cylinder head of the vertical axis type internal combustion engine of the present invention covers and covers the recess for the water jacket formed in the cylinder head, and extends over the entire length of the cylinder head. The bolt hole that is attached to the cylinder head also serves as a hole for inserting a thermocouple, the side cover holds the thermostat, and a bypass path from inside the water jacket is formed in the side cover. It is constructed by guiding the bypass passage to the exhaust passage.

An embodiment of the present invention will be described below with reference to the drawings.
The figure is a side view of the main parts seen from the side lid direction of FIG. 1.

First, in this internal combustion engine, the crankshaft (not shown) is arranged in the vertical direction, and therefore No. 1 and No. 2
This is a vertical shaft type internal combustion engine for an outboard motor in which the cylinders of each cylinder shown in Fig. 1 are arranged horizontally, and each intake port 2 of each cylinder No. 1 and No. Intake air A is introduced into the engine, and exhaust gas E after combustion of the injected fuel is exhausted from each exhaust port 3 to the exhaust passage 4 below the cylinder head 1. 2 and around the exhaust port 3 is a water jacket 5.
is formed.

Therefore, the left side of the water jacket 5 formed in the cylinder head 1 as shown in FIG. A side cover 6 is attached and covered with a large number of bolts 7.

That is, since the water jacket 5 formed on the cylinder head 1 is cast in the form of a recess that opens toward the side lid 6, the core can be easily supported during casting.

Further, the thermostat 8 inserted into the upper part of the water jacket 5 can be held in place by attaching the side cover 6.

Furthermore, on the inside of this side lid 6, one anti-corrosion zinc 9 is attached to the top and bottom of the water jacket 5 to prevent corrosion of the water jacket 5 portion.

Conventionally, such anti-corrosion zinc 9 was attached to the cylinder block or cylinder head 1 itself by screwing, and depending on the attachment position, it was very difficult to replace it, but as in this embodiment, the anti-corrosion zinc 9 By installing it on the holder, its replacement becomes very easy. Since the side cover spans the entire length of the head, anti-corrosion zinc can be applied to both end surfaces of the swimsuit, providing a great anti-corrosion effect.

Further, a bypass passage 10 is formed in advance in this side lid 6, which communicates from the upper thermostat outlet in the water jacket 5 to the lower part of the cylinder head 1. The exhaust gas is led out from the bypass passage 10 via its outlet 11 to the exhaust passage 4, is sufficiently mixed with the exhaust gas E, and is discharged to the outside while cooling the exhaust gas E. This prevents the outboard motor body from being overheated by the exhaust gas E. can be prevented. In this case, the exhaust port is installed inside the head, and especially if the exhaust port is for an outboard motor, it is necessary to provide a water jacket around the entire outer circumference of the exhaust port to prevent the engine from overheating. , the lid forms the water dependent part of this. If this is formed from the head body instead of the lid, the casting will be complicated.

In addition, in this embodiment, there are ten bolts 7 shown in FIG. 2 that attach the side cover 6 to the cylinder head 1.
Of these, holes penetrating the exhaust ports 3 are provided in the bolt holes of the two central bolts 7 located in the exhaust ports 3 of the No. 1 and No. 2 cylinders, and each cylinder No.
When measuring the exhaust temperature of No. 1 and No. 2, remove this bolt 7 and attach the thermocouple 12 shown by the two-dot chain line at the tip.
By replacing the bolt with a bolt that incorporates the bolt, it is possible to measure the exhaust temperature of each cylinder No. 1 and No. 2 while the engine is still in its working state, and check the engine performance.

Therefore, if the cylinder head of the present invention is applied to a vertical axis type internal combustion engine, the cylinder head with the water jacket formed thereon can be easily cast, and the thermostat inserted into the water jacket can be easily held. The present invention has the advantage that a cylinder head can be provided, the casting cost of the cylinder head can be reduced, and inspection and maintenance inside the water jacket can be facilitated.

In addition, a particularly significant effect is that the bolt holes used to connect the side cover and cylinder head also double as thermocouple insertion holes, so there is no need to provide a special thermocouple hole, making it easy to use whenever needed. A thermocouple can be used for the outboard engine, and a bypass path from inside the water jacket is formed in the side lid, and the bypass path is led to the exhaust passage, which allows the exhaust gas to be cooled and prevents the outboard engine from being overheated by the exhaust gas. It can be prevented.

[Brief explanation of drawings]

FIG. 1 is a front sectional view of a main part of a cylinder head of a vertical axis type internal combustion engine according to an embodiment of the present invention, and FIG. 2 is a side view of the main part as seen from the side lid direction of FIG. 1...Cylinder head, 5...Water jacket,
6...Side lid, 7...Bolt, 8...Thermostat, 10...Bypass path.

Claims (1)

[Claims] 1. In an internal combustion engine in which the crankshaft is arranged vertically, a side cover is installed over the entire length of the cylinder head and covers a recess for a water jacket formed on the side of the cylinder head over almost the entire length. The bolt hole connected to the water jacket was also used as a hole for inserting a thermocouple, the thermostat was held in the side cover, a bypass path from inside the water jacket was formed in the side cover, and the bypass path was led to the exhaust path. A cylinder head for a vertical axis internal combustion engine characterized by: