JPS63198756A - Cylinder head of engine - Google Patents

Abstract

PURPOSE:To make diecasting formation of a cylinder head possible, by making an intake and exhaust air passages formed in a cylinder head in tapered forms enlarging their diameters as going away from a combustion chamber and making the axle line of the opening of each passage facing the combustion chamber in parallel to the axle line of a cylinder. CONSTITUTION:At a cylinder head 4 of a diesel engine, a valve stem guide 26 and an inlet and an exhaust port 27a, 27b are provided in series along a crank shaft line so as to make the positions of inlet and exhaust valves nearly right above the crank shaft. An intake passage 32 is formed from an intake port 27a toward the left side of the cylinder head. An upper view of axle line of this passage 32 is formed exccentically to the center of the inlet port 27a and is extended linearly in a tangential direction. An exhaust passage 33 extended from the exhaust port 27b is formed nearly along the crank shaft line and the axle line of this exhaust passage 33 is also made linear. And both passage 32, 33 are made in tapered forms enlarging their diameters as going to the outside.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an engine cylinder head, and more particularly to an engine cylinder head configured so that it can be formed by die-casting.

<Prior Art> Conventionally, the cylinder head of an engine has been formed by casting using, for example, an aluminum alloy. Such a cylinder head includes an air-fuel mixture intake passage, a combustion gas exhaust passage, valve guides and valve seats that open and close the openings of these passages to the combustion chamber, and a valve seat that drives these valves.
- It is necessary to form an insertion hole for the bushing rod, etc., and the structure tends to become complicated. Furthermore, in the case of a diesel engine cylinder head that has a flat surface facing the piston, in order to improve combustion efficiency, it is necessary to form an intake passage in order to create a swirl in the air-fuel mixture flowing into the combustion chamber. It tends to be troublesome.

On the other hand, die-casting, in which molten metal is injected under pressure into a mold, is known as one of the precision casting methods, and if this is applied to the formation of cylinder heads, it will greatly simplify the engine manufacturing process. It is considered possible to do so.

<Problems to be Solved by the Invention> However, the cylinder head has a relatively complicated shape as described above, and the treatment of the core for forming the intake and exhaust passages is particularly troublesome. It was difficult to apply die-cast molding.

In view of the findings of the present inventors and the problems of the prior art, the main object of the present invention is to provide an engine cylinder head that can be formed by die-casting.

<Means for Solving the Problems> According to the present invention, such an object is to provide a cylinder head of an engine, in which an intake passage and an exhaust passage are provided inside the cylinder head to communicate with a combustion chamber. , has a tapered shape whose diameter increases as it moves away from the combustion chamber, and
The axes of both passages are approximately straight, and
This is achieved by providing a cylinder head for an engine, wherein the axes of openings of the intake passage and the exhaust passage to the combustion chamber are parallel to the cylinder axis of the engine.

In this way, both the intake and exhaust passage portions can be formed using a punched core, making it possible to form the cylinder head by die-casting.

<Embodiments> The present invention will now be described in detail with reference to specific embodiments with reference to the accompanying drawings.

FIG. 1 schematically shows a diesel engine to which a cylinder head according to the present invention is applied.

This diesel engine 1 includes an oil pan 2 that stores lubricating oil therein, a cylinder block 3 that is installed to close an opening of the oil pan 2, a cylinder head 4 that is attached to the upper part of the cylinder block 3, and a cylinder head 4 that is attached to the top of the oil pan 2. It has a cylinder head cover 5 that closes the upper part of the cylinder head.

Inside the cylinder head 4, there is an injection nozzle 6 for injecting fuel into the combustion chamber, an intake valve and an exhaust valve.
A pair of valves 7 are respectively provided. These valves 7 are
The valve is normally biased by a spring in the direction of closing the valve, and is driven to open by a pair of rocker arms 8 that operate in conjunction with a cam.

In FIG. 1, only one of the intake and exhaust valves is shown.

A cylinder 9 is formed inside the cylinder block 3, and screws 1 to 10 are slidably fitted inside the cylinder 9. The piston 10 is connected to a crankshaft 12 via a connecting rod 11, and is configured to convert reciprocating motion of the screws 1 to 10 due to combustion pressure of fuel into rotational motion of the crankshaft 12. A combustion chamber 10a is recessed in the upper end surface of the piston 10.

A crankcase 13 is formed on the lower end side of the cylinder block 3 in cooperation with the oil pan 2. Inside the crankcase 13, the above-described crankshaft 12, a balancer shaft 14 and a camshaft 15 are arranged adjacent to each other in parallel on both sides of the crankshaft 12, and the fuel is pressurized through the injection nozzle 6 into the combustion chamber 10a. an injection pump 16 to inject the
A governor mechanism 17 is provided to automatically control the fuel discharge m.

The cam shaft 15 has a cam 15a having a predetermined contour.
are formed, the tappet 18 and the bushing rod 1
By transmitting the lift of the cam 15a to the rocker arm 8 through the rocker arm 9, the suction and exhaust valves 7 are driven to open and close according to predetermined timing, and the plunge i' of the injection pump 16 is driven. There is.

FIGS. 2 and 3 show the cylinder head 4 portion of the engine described above in detail. The cylinder head 4 is formed by die-casting an aluminum alloy by C.degree. centigrade casting, and is ground into a flat surface in order to fix the head cover 5 to the upper surface S1 and to join the lower surface S2 to the upper end surface of the cylinder block 3. ing.

This cylinder head 4 is located almost directly above the crankshaft.
A pulp stem guide 26 and suction/exhaust boats 27a, b are arranged in series along the crank axis so that the exhaust valve 7 is located, and a pair of head bolt holes 28 are located to the right of these. A pair of head bolt holes 29 are similarly provided on the left side, and a pair of bush rod guide holes 30 are provided on the left side. These are arranged approximately symmetrically with respect to a line perpendicular to the axis of the crankshaft, and the intake boat 27a on this line.
A nozzle hole 31 into which the tip of the injection nozzle 6 is inserted is bored in a portion close to the exhaust port 27b.
Figure 3).

From the intake boat 27a toward the left end surface of the cylinder head 4 [
An intake passage 32 is formed. This intake passage 3
2 communicates with the outside by passing through the pair of head bolt holes 29 on the left side of the suction and exhaust boats 27a and b, and the pair of bushing rod guide holes 30 on the left side thereof. The axis line viewed from the top surface is eccentric with respect to the center of the intake boat 27a, and forms a straight line extending in the tangential direction, and its outer diameter increases as it goes outward. It has a tapered shape.

The exhaust passage 33 communicating with the outside from the exhaust port 27b is
The exhaust passage 33 extends along the crank axis, and the axis of the exhaust passage 33 is a straight line, and the exhaust passage 33 has a tapered shape with an outer diameter increasing toward the outside.

In addition, the intake and exhaust ports 27a and 27b and the pulp stem guide 26 corresponding to these are arranged with their respective axes parallel to the cylinder axis, and in particular, the intake and exhaust passages 3
2. Portion 2 that becomes M from 33 to intake and exhaust ports 27a and b
7 is also formed coaxially with the pulp stem guide 26 (FIG. 2).

A plurality of cooling fins 34 are formed on the right side wall of the cylinder head 4 in order to improve cooling efficiency. A first ventilation passage 35 is formed parallel to the WIJ line of the crankshaft between the head bolt hole 28 and the intake/exhaust boats 27a and 27b for cooling air to flow therethrough. Similarly, a second ventilation passage 36 is provided above the intake passage 32 and at an intermediate portion between the intake/exhaust boats 27a, b and the head bolt hole 29. And these first and second ventilation passages 35
．． The third ventilation passage 37 runs along the line so that the intake and exhaust air between the boats 27a and 36 communicate with each other at the middle part of the boats 27a and 27b.
It is formed by Further, a fourth ventilation passage 38 is bored below the intake passage 32 and at an intermediate portion between the head bolt hole 29 and the bushing rod guide hole 30 adjacent thereto.

In addition, as shown by the imaginary line in FIG. 2, a part of the injection nozzle 6 is exposed at the intersection of the first and third ventilation passages 35, 37, so that sufficient cooling air is supplied to the injection nozzle 6. It is made to be true.

As mentioned above, cylinder heads generally tend to have a relatively complicated shape, and especially when the intake passage is made long, it becomes difficult to handle the mold, making it difficult to manufacture by molding into so-called die-cast I. Met.

Therefore, in the present invention, the suction and exhaust side passages 32 and 33 are formed into a linear tapered shape, and the portions 27 connected to both the suction and exhaust boats 27a and b are formed into a straight line parallel to the cylinder axis. This makes it possible to handle types. Further, as shown in the above embodiment, the center axis line of the intake passage 32 as viewed from the top surface is made eccentric with respect to the center of the intake boat 27a, and the intake passage 32 is
By extending substantially tangentially to the air, it is possible to obtain an intake passage shape that can create a swirl in the intake air flow without deteriorating the manufacturability.

<Effects of the Invention> As described above, according to the present invention, it is possible to form the intake and exhaust side passages using a handling core, and the cylinder head can be manufactured by die-casting I-molding, thereby simplifying the engine manufacturing process. Simplification has a huge effect.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing the entire diesel engine to which the present invention is applied. FIG. 2 is an enlarged longitudinal cross-sectional view showing the cylinder head shown in FIG. 1 taken along line 2--2 in FIG. 3. FIG. FIG. 3 is an enlarged cross-sectional view taken along the line ■-■ in FIG. 2. 1... Deep Pill engine 2... Oil pan 3... Cylinder block 4
...Cylinder head 5...Cylinder head cover 6...Injection nozzle 7...Valve 8...Rocker arm 9...Cylinder 10...
Piston 10a... Combustion chamber 11... Connecting rod 12... Crankshaft 13... Crank case 14... Balancer shaft 15... Camshaft 15a
... Cam 16 ... Injection pump 17 ... Governor mechanism 18 ... Tappet 19 ... Bush rod 26 ... Valve stem guide 27 ... Part 27a ... Intake boat 27
b...exhaust boat

Claims (2)

[Claims] (1) A cylinder head of an engine, in which an intake passage and an exhaust passage installed internally in the cylinder head to communicate with the combustion chamber form a tapered shape whose diameter increases as the distance from the combustion chamber increases, and both of these passages A cylinder head for an engine, wherein the axes of the intake passage and the exhaust passage are substantially straight, and the axes of openings of the intake passage and the exhaust passage with respect to the combustion chamber are parallel to a cylinder axis of the engine. (2) The central axis of the intake passage viewed from the top surface is eccentric with respect to the center of the opening, and the intake passage extends approximately tangentially to the opening. A cylinder head for an engine according to claim 1.