JPS6211309Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of a sub-combustion chamber of a diesel engine, particularly to the structure of a sub-combustion chamber consisting of a main sub-combustion chamber and a pre-combustion chamber.

A structure in which a sub-combustion chamber is formed using a ceramic sub-combustion chamber-forming member has been developed in the past. However, if only ceramic material is used, a problem arises in that the strength is significantly lower than that of steel afterburning chamber forming members. On the other hand, if the strength is to be increased, the thickness of the ceramic material must be significantly increased, and the size of the auxiliary combustion chamber forming member is unavoidable.

The present invention aims to increase the strength without increasing the size of the auxiliary combustion chamber forming members, that is, the auxiliary combustion main chamber forming member and the auxiliary combustion front chamber forming member, using ceramic materials. The gist is that the main chamber forming member that forms the main chamber and the front chamber forming member that forms the front chamber are each made of ceramic material, the outer peripheral surface of the main chamber forming member is wrapped with a steel pipe, and the main chamber forming member and the front chamber forming member are made of ceramic material. A metal spacer is disposed between the auxiliary chamber forming member and the both chamber forming members are pressed and fixed within the cylinder head by a metal holding member. The present invention will be explained below based on the drawings.

In the drawing, 1 is a cylindrical main chamber forming member that forms the sub-combustion main chamber 2, 3 is a cylindrical front chamber forming member that forms the sub-combustion front chamber 4, and both members 1 and 3 are made of ceramic. It is made of material. The front chamber forming member 3 has a hemispherical lower end and is provided with a communication port 5 in the hemispherical portion, through which the front chamber 4 is communicated with the main combustion chamber 7 . Further, a flange 10 is formed in the middle of the vertical width of the front chamber forming member 3 and extends outward in the radial direction. The lower end inner peripheral hole 11 of the main chamber forming member 1 is fitted and connected to the upper end portion of the front chamber forming member 3, and an annular steel spacer is provided between the upper surface of the flange 10 and the lower end surface of the main chamber forming member 1. 12 are arranged. Further, between the upper and lower surfaces of the spacer 12, the lower end surface of the main chamber forming member 1, and the upper surface of the flange 10, annular thin sheet steel packings 1 are provided.
3 and 14 are arranged. The main chamber forming member 1 has an outer diameter larger than the flange outer diameter of the front chamber forming member 3, and a cylindrical steel pipe 15 is fitted onto the outer peripheral surface of the main chamber forming member 1 with, for example, a constant pressure. ing. The spacer 12 is formed to have the same outer diameter as the outer diameter of the steel pipe 15, and an annular recess 12a having substantially the same outer shape as the flange 10 is formed on the inner peripheral side of the upper surface of the spacer 12. That is, the outer circumferential side of the upper surface of the spacer 12 comes into contact with the outer circumferential side of the lower end surface of the main chamber forming member 1 via the gasket 13, and the main chamber forming member 1
It receives the downward pressing force (tightening force) of , and transmits it to the front chamber forming member 3 via the spacer 12 . Further, the inner circumferential portion of the lower surface of the spacer 12 contacts the flange 10 via the packing 14, and as described above, the spacer 1
The spacer 12 functions as a spring cushion between the two members 1 and 3 by abutting the outer circumferential portion of the upper surface of the main chamber forming member 1 with the outer circumferential portion of the lower end surface of the main chamber forming member 1 .

Both members 1 and 3 are connected to the hole 1 of the cylinder head 16.
A steel presser member 21 is placed on the upper end surface of the main chamber forming member 1 via an annular steel ring 20. The main chamber forming member 1 is pressed down. The steel ring 20 is the main chamber forming member 1
It is in contact with the outer peripheral end of the upper surface and the upper surface of the steel pipe 15 . That is, the outer peripheral end of the main chamber forming member 1 having the highest strength and the steel pipe 15 are pressed down. The holding member 21 is fastened to the cylinder head 16 with a tightening bolt 22 or the like.

23 is a fuel injection valve, which includes a valve insertion hole 24 of the holding member 21 and an upper insertion hole 25 of the main chamber forming member 1.
The lower end nozzle portion of the injection valve 23 faces the main chamber 2 .

Reference numeral 28 is a cylindrical partition member that separates the main chamber forming member 1 and the like from the water jacket 26 within the cylinder head 16. 27 is an oil leak passage.

As explained above, the present invention is a diesel engine equipped with a sub-combustion chamber consisting of a sub-combustion main chamber 2 and a sub-combustion pre-chamber 4, in which the main chamber forming member 1 forming the main chamber 2 and the pre-combustion chamber 4 are formed. The front chamber forming members 3 are each made of ceramic material, and the main chamber forming member 1
A metal spacer 12 is arranged between the main chamber forming member 1 and the front chamber forming member 3, and both chamber forming members 1 and 3 are held together by a metal holding member 21. Since it is pressed and fixed within 16,
It has the following advantages: That is: (1) Since both the chamber forming members 1 and 3 are made of ceramic material and are formed separately, it is easy to manufacture the chamber forming members 1 and 3 that form the sub-combustion chamber with a complicated shape, and Weight reduction can also be achieved.

(2) Since the outer peripheral surface of the main chamber forming member 1 is wrapped with the steel pipe 15, the steel pipe 15 plays the role of a reinforcing ring, and the main chamber pressure can be increased without increasing the wall thickness of the main chamber forming member 1. The strength against is improved.

(3) Since the metal spacer 12 is arranged between the two chamber forming members 1 and 3, even if the outer diameters of the two chamber forming members 1 and 3 are different, for example, the main chamber forming member 1 Even if the outer diameter is larger than the outer diameter of the front chamber forming member 3 (flange 10), the strongest outer peripheral end portion of the main chamber forming member 1 is held down by the holding member 21, for example, via the steel ring 20, Furthermore, the clamping force (pressing force) can be reliably transmitted to the front chamber forming member 3. That is, even if the main chamber forming member 1 etc. is pressed strongly by the presser member 21, the main chamber forming member 1 etc. made of ceramic can be prevented from being damaged, so both members 1 and 3 can be strongly and reliably tightened. I can do it.

(4) Also, as shown in the figure, when the outer diameter of the main chamber forming member 1 is larger than the outer diameter of the front chamber forming member 3 (flange 10), an annular recess 12a is formed in the inner circumferential portion of the upper surface of the spacer 12. Then, the main chamber forming member 1 is brought into contact with the outer peripheral side of the upper surface of the spacer 12, and the flange 1 of the front chamber forming member 3 is brought into contact with the inner peripheral side of the lower surface of the spacer 12.
If the upper surface of 0 is brought into contact with the spacer 12
serves as a spring cushion between both members 1 and 3. Therefore, even if excessive upward pressure is applied from the main combustion chamber 7 to the front chamber forming member 3,
Both members 1 and 3 will not be damaged.

In the present invention, the presser member 21 and the spacer 12 can be manufactured by casting. Further, the steel pipe 15 may simply be fitted onto the outer peripheral surface of the main chamber forming member 1, or may be formed by sintering.

[Brief explanation of the drawing]

The drawing is a partial vertical cross-sectional view of a diesel engine to which the present invention is applied. DESCRIPTION OF SYMBOLS 1... Main chamber forming member, 2... Sub-combustion main chamber, 3... Front chamber forming member, 4... Sub-combustion front chamber, 12... Metal spacer, 15... Steel pipe, 16...
...Cylinder head, 21...Metal holding member.

Claims (1)

[Scope of utility model registration request] In a diesel engine equipped with a sub-combustion chamber consisting of a sub-combustion main chamber and a sub-combustion pre-chamber, the main chamber-forming member forming the main chamber and the front-chamber forming member forming the front chamber are each made of ceramic material, and the main chamber is The outer peripheral surface of the forming member is wrapped with a steel pipe, a metal spacer is placed between the main chamber forming member and the sub chamber forming member, and both chamber forming members are pressed and fixed within the cylinder head by a metal holding member. The sub-combustion chamber structure of a diesel engine is characterized by: