JPH0267421A - Head cooling device for liquid and air cooling serial multi-cylinder engine - Google Patents

Abstract

PURPOSE:To improve the cooling performance of a small-size engine and offer the high power characteristics for the engine by forming a coolant passage which carries coolant into a coolant chamber, through the wall of a port which goes between a pair of push rod insert holes. CONSTITUTION:Either of an intake part 8 or an exhaust port 9 is formed between a pair of push rod insert holes 10 which are formed for each cylinder. A coolant chamber 12 is formed as surrounding a supplementary chamber 11. In addition a coolant passage 13 which carries coolant into the coolant chamber 12 is formed through both the bottom wall of one of the ports and the wall between valves. The part between the push rod insert holes of adjacent cylinders are used as a coolant passage 15.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a cooling device for a cylinder head in an in-line multi-cylinder engine.

(Prior art) Conventional multi-cylinder diesel engines are cooled by cooling water flowing through the water jacket formed around the cylinders and in the combustion chamber layer, or by using cooling air generated by a cooling fan driven by the engine to cool the engine. It was used to cool the body by spraying it on the body.

(Problem to be Solved) In a diesel engine, fuel is injected into combustion air compressed by a piston and combusted, but this combustion is performed with the piston at a position near top dead center.

Since the cylinder head section is directly heated by this combustion, it is necessary to sufficiently cool that section, but the lower circumferential wall of the cylinder/rel section is heated to a lesser degree than the combustion chamber section. low. In consideration of friction with the piston, it is desirable to maintain the lower peripheral wall portion of the cylinder barrel at a high temperature to the extent that the piston does not seize.

By the way, in a water-cooled engine, a water jacket is formed inside the engine body, and a single system of cooling water is circulated within the water jacket, so cooling of the cylinder barrel part is moderate and the combustion chamber part is cooled. Since it is not possible to use a cooling method that provides powerful cooling, there is a problem that optimum cooling performance cannot be obtained.In addition, since the water shank must be filled with cooling water, the engine There is a problem in that the engine itself is heavy, and also requires a heat radiator (for example, a radiator) to dissipate the heat retained in the cooling water, making the engine unit larger and limiting its uses.

On the other hand, in an air-cooled engine, heat is exchanged through contact between the circulating air and the engine wall, so the degree of cooling due to the heat exchange is low.

For this reason, it is difficult to sufficiently cool the area around the combustion chamber, which tends to become hot, especially the heat storage areas such as the vortex chamber and a part of the nozzle holder, and there is also the problem of large engine noise.

Therefore, in a single-cylinder diesel engine, a coolant chamber is formed in the subchamber part formed in the head block.
It has been proposed that the pre-chamber part is cooled with a cooling fluid and other parts are cooled with cooling air, but in the case of a single-cylinder engine, there is a degree of freedom in the direction of the intake boat and exhaust port. Because of this, the coolant passage can be formed arbitrarily, avoiding the intake and exhaust ports.
In the case of a multi-cylinder engine, there are many restrictions on the direction in which the intake port and exhaust port are led out, making it difficult to form a coolant passage.

The present invention has been made with attention to these points, and an object of the present invention is to provide an in-line multi-cylinder engine that improves cooling performance and can obtain high output even though it is a small engine.

(Means for Solving the Problems) In order to achieve the above object, the present invention arranges the valve ports of the intake port and exhaust port in each cylinder of an in-line multi-cylinder engine one after the other, and horizontally aligns the two ports. In the cylinder head of a multi-cylinder engine, which has an auxiliary chamber formed on one side and a push rod insertion part on the other side, a push rod is formed so that either the intake port or the exhaust port corresponds to each cylinder. The insertion holes are arranged so that they pass through the same dirt floor, and a coolant chamber is formed around the auxiliary chamber, and the coolant passage that supplies coolant to this coolant chamber is arranged so that it passes through the same dirt floor as the pair of push rod insertion holes. It is characterized by being transparently installed so as to pass through the bottom wall of the arranged port and the wall between the valves, and a cooling air passage is formed between the plug-nosher rod insertion hole portions of adjacent cylinders.

(Function) In the present invention, either one of the intake port and the exhaust port is arranged so as to pass through the same dirt floor as the through hole of the intake port and the exhaust port formed corresponding to each cylinder, and a coolant chamber is provided around the auxiliary chamber. A coolant passage for supplying coolant to the coolant chamber is installed through the bottom wall of the port, which is arranged so that it passes through the same dirt floor as the pair of push rod insertion holes, and the wall between the valves. However, since a cooling air passage is formed between the push rod insertion holes of adjacent cylinders, even though the cooling fluid passage is formed in the intake port and exhaust port, the subchamber part that becomes the heat storage area is Of course, the wall between the valves can be cooled with cooling liquid. Moreover, since one of the intake port and the exhaust port is formed to pass between the push rod hole portions, the cooling air path can be formed wide, and the overall cooling performance is improved.

(Embodiment) The drawings show an embodiment of the present invention; FIG. 1 is a cross-sectional plan view of a cylinder head of a two-cylinder diesel engine, and FIG.
A vertical side view of the cylinder diesel engine, FIG. 3 is a sectional view taken along the line ■-■ in FIG. 1, and FIG. 4 is a sectional view taken along the line IV-IY in FIG.

This engine has a crankcase (1) and a cylinder block (2) integrally formed.
A head block (3) is fixed to the upper side to form an engine body (E), and a cooling fan (
6) is fixed, the cooling fan (6) is surrounded by a wind guide case (7), and the cooling air generated by the cooling fan (6) is sent to the cylinder block (2) section and the head block (3) section. This is to cool the engine.

The head block (3) has an intake port (8) and an exhaust port (9) arranged corresponding to each cylinder.

As shown in FIG.
8a) (9a) is approximately on the cylinder center line and the crankshaft (
5) to create a cross flow, and the intake valve ports (8a) and the exhaust valve ports (9a) are located close to each other, and
The exhaust valve ports (9a) are arranged so as to be separated from each other.

The intake ports (8) led out from each cylinder merge and open in the earthen wall of the head block (3). On the other hand, the exhaust ports (9) led out from each cylinder are opened on the side surface of the head block (3), passing between push rods arranged corresponding to each cylinder. For this reason, the push rod insertion hole (10), which is formed to surround the push rod, is divided and formed on both sides of the exhaust port (9).

A spherical auxiliary chamber (11) is formed between the intake valve port (8a) and the exhaust valve port (9a) of each cylinder on the side opposite to the outlet direction of the exhaust port (9). A coolant chamber (12) is formed surrounding the chamber (11).

The coolant passage (13) that supplies the coolant to the coolant chamber (12) is connected to the exhaust port (9) as shown in FIG.
The coolant passage (13) is formed to pass through the valve gap between the intake valve port (8a) and the exhaust valve port (9a) in each cylinder. The coolant chamber (12) is supplied with a portion of the engine lubricant oil pumped by a lubricant pump (shown in the diagram), and is configured so that a portion of the engine lubricant oil acts as a coolant. It is. Note that the lubricating oil heated in the coolant chamber (12) is an oil placed in the air passage that guides the cooling air blown by the cooling fan (6) to the head block (3) and cylinder block (2). After the heat is radiated by a cooler (the path shown), it is returned to the oil reservoir (14) in the crankcase (1).

A cooling air passage (15) is formed in the head block (3), and the cooling air generated by the cooling fan (6) flows through the cooling air passage (15) in the head block (3). The head block (3) is cooled by air. In this case, since the exhaust ports (9) are formed to pass between the push rods, the gap between adjacent exhaust ports (9) can be widened, and the intake ports (8) can be merged. Since the cooling air passage (15) in the head block (3) is opened in the earthen wall of the head block (3), it is possible to form a wide cooling air passage (15).

In the above embodiment, the intake ports (8) merge and open in the earthen wall of the head block (3), and the exhaust ports (9) are arranged between a pair of push rods in each cylinder. Arrange the exhaust ports (9) of matching cylinders close together, merge both exhaust boats (9), and connect the head block (3).
), and each intake port (8) may be arranged between push rods in each cylinder.

Further, in the above embodiment, engine lubricating oil was used as the coolant to be supplied to the combustion chamber layer, but a dedicated coolant (for example, cooling water) may be used.

(Effects) In the present invention, either the intake port or the exhaust port is arranged so that it passes through the push rod insertion hole formed in correspondence with each cylinder, and a coolant chamber is formed around the subchamber. , a coolant passage for supplying coolant to the coolant chamber is provided so as to pass through the bottom wall of the port, which is arranged to pass through the same dirt floor as the pair of push rod insertion holes, and the wall between the valves; A cooling air passage is formed between the push rod insertion holes of adjacent cylinders, so even though the cooling fluid passage is formed in the intake port and exhaust port, there is of course a cooling air passage in the subchamber, which is the heat storage area. The inner wall of the portion between the valves, which tends to heat up, can be cooled with the cooling liquid. Furthermore, since one of the intake and exhaust ports is formed to pass between the bush cId holes, it is possible to form a wide cooling air passage within the head block, improving overall cooling performance. do.

This makes it possible to provide a compact, high-output engine.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a cross-sectional plan view of a cylinder head of a two-cylinder diesel engine, and FIG.
A vertical side view of the cylinder diesel engine, FIG. 3 is a sectional view taken along the line ■--■ in FIG. 1, and FIG. 4 is a sectional view taken along the line IV--IV in FIG. 8...Intake port, 8a...Valve port part of (8), 9
...Exhaust port, 9a...Valve port part of (9), 10
...Push rod insertion hole, 11...Subchamber, 12.
・・Cooling liquid chamber Fig. 1 ■ 紫−＋＋◆m 13...Cooling liquid passage, 15...Cooling air passage.

Claims (1)

[Claims] 1. An intake port (8) and an exhaust port (9) in each cylinder of an in-line multi-cylinder engine in which a plurality of cylinders are arranged in parallel in the front and rear.
) are arranged in front and behind each other, and a sub-chamber (11) is formed on one lateral side between both ports (8) and (9), and a push rod is placed on the other lateral side. Insertion hole (10)
In the cylinder head of a multi-cylinder engine, one of the intake port (8) and the exhaust port (9) is made to correspond to each cylinder, and a pair of push rod insertion holes (10) are formed so as to pass through the same dirt floor. A coolant passage (1) is arranged to form a coolant chamber (12) around the auxiliary chamber (11), and supplies coolant to the coolant chamber (12).
3) is inserted through the bottom wall of the port which is arranged to pass between the pair of push rod insertion holes (10) and the flesh wall of the valve space, and the push rod insertion hole portion of the adjacent cylinder is A head cooling device for a liquid-cooled and air-cooled in-line multi-cylinder engine, characterized in that a cooling air passage (15) is formed between