JPH0229235Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to an improvement of a pre-chamber type diesel engine.

(Prior art) As seen in Japanese Utility Model Application Publication No. 56-142223, a sub-chamber is defined by attaching a sub-chamber insert with a nozzle to a cylinder block, and the sub-chamber and main combustion chamber are connected to each other by a nozzle. In a pre-chamber type diesel engine that communicates with the pre-chamber through a compression stroke, compressed air is sent to the pre-chamber using the compression stroke, and fuel is injected into the pre-chamber from a fuel injection nozzle and ignited within the pre-chamber. ing.

By the way, while the pre-chamber insert is heated by the combustion gas passing through the nozzle, it is rapidly cooled by the compressed air sent into the combustion chamber.
There is a problem in that cracks are likely to occur at the bottom of the pre-chamber insert that comes into pressure contact with the cylinder block.

In particular, when the pre-chamber insert is made of ceramic and the pre-chamber is made into an adiabatic combustion chamber, the combustion gas passing through the nozzle becomes even hotter, so the above-mentioned problem becomes more pronounced.

(Purpose of the invention) The purpose of the invention is to provide a pre-chamber type diesel engine in which the thermal load on the pre-chamber insert is reduced by forcibly cooling the bottom of the pre-chamber insert where cracks are likely to occur. Our goal is to provide the following.

(Structure of the invention) In order to achieve this purpose, the invention includes the following:
The bottom of the subchamber insert is forcibly cooled using the cooling water in the water jacket. Specifically, the gasket interposed between the cylinder block and the cylinder head has a gasket body and a heat transfer plate attached to the cylinder head side of the gasket body, and the gasket body includes: A through hole is provided near the bottom of the subchamber insert, the cylinder head side opening of the through hole is closed with the heat transfer plate, and the heat transfer plate is extended to the bottom of the subchamber insert to connect the subchamber insert to the bottom. While making contact with the heat exchanger plate, the through hole is communicated with the water jacket in the cylinder block through a passageway, and the cooling water in the water jacket is guided to the through hole and brought into contact with the heat exchanger plate. The heat at the bottom of the chamber insert is forcibly removed by cooling water via a heat transfer plate, thereby suppressing the rise in temperature at the bottom of the sub-chamber insert where cracks are likely to occur.

(Example) An example in which the present invention is applied to a swirl chamber type diesel engine will be described below with reference to the drawings.

In Fig. 1, reference numeral 1 denotes a cylinder block, on which a cylinder head 3 is placed and fixed via a gasket 2, and a piston 4 slidably inserted into the cylinder block 1 connects the main combustion chamber. 5 is defined.

A vortex chamber 6 is provided in the cylinder head 3 facing the main combustion chamber 5, and a fuel injection nozzle 7 and a glow plug 8 are disposed in the vortex chamber 6.

The vortex chamber 6 has a two-part structure ceramic member (subchamber insert) 10,1 inserted into the sleeve 9.
The pre-chamber inserts 10 and 11 are made of silicon nitride, which has excellent heat resistance. One subchamber insert 1 forming the bottom of the vortex chamber 6
1 is partially supported on the top surface of the cylinder block 1. The subchamber insert 11 has a spout 12
A nozzle 12 is opened facing the main combustion chamber 5, and the vortex chamber 6 and the main combustion chamber 5 are communicated through the nozzle 12.

As shown enlarged in FIGS. 2 and 3, the gasket 2 has a gasket body 1 made of asbestos.
3, and a grommet 14 that borders the inner peripheral edge of the gasket body 13.

The gasket body 13 is provided with a gasket body 1 in the vicinity of the part that comes into contact with the subchamber insert 11 described above.
Through holes 15, 15 are drilled through 3.

On the other hand, the grommet 14 is connected to the gasket body 13.
The grommet 14 and the gasket are extended to a size sufficient to abut the bottom of the vortex chamber insert 11 and close the opening of the through hole 15 on the cylinder head 3 side on the cylinder head 3 side surface of the grommet 14. It is joined to the main body 13 with an adhesive, and the through hole 15 is made waterproof with this adhesive.

The through hole 15 provided in this gasket 2 is
It is communicated with the water jacket 1a of the cylinder block 1 via a water passage 16.

The water passage 16 is formed by extending the water jacket 1a to the top surface of the cylinder block 1, and the water passage 16 is opened at a position facing the through hole 15 described above.

In such a configuration, in addition to the combustion within the vortex chamber 6, the heat of the pre-chamber insert 11 heated by the combustion gas passing through the nozzle 12 is transmitted to the grommet 14 which is in pressure contact with the bottom of the pre-chamber insert.
4, the cooling water in the water jacket 1a is taken away.

From this, it can be seen that while the combustion temperature increases by making the vortex chamber 6 ceramic, the bottom of the pre-chamber insert is forcibly cooled by the cooling water in the water jacket 1a, so the temperature rises. This prevents the subchamber insert 11 from cracking.

On the other hand, since the through-hole 15 and the water passage 16 are provided in a manner that avoids the sub-chamber insert 11, the support of the sub-chamber insert 11 is ensured as in the conventional case.

Although one embodiment of the present invention has been described above, the present invention can also be applied to a pre-combustion chamber type diesel engine. Furthermore, a heat exchanger plate large enough to close the opening of the through hole 15 and extend to the bottom of the auxiliary chamber (vortex chamber 6) may be attached to the surface of the gasket body 13 on the side of the cylinder bed 3. good.

(Effect of the invention) As is clear from the above explanation, according to the invention, the bottom of the subchamber insert is forcibly cooled by the cooling water of the water jacket via the heat transfer plate, so that the bottom of the subchamber insert is Since the temperature rise in the subchamber insert is suppressed and the thermal load on the subchamber insert is thereby reduced, it is possible to prevent the occurrence of cracks in the subchamber insert.

[Brief explanation of drawings]

FIG. 1 is an overall sectional view showing one embodiment of the present invention.
Figure 2 is a front view of the gasket. FIG. 3 is a cross-sectional view taken from FIG. 2. 1: cylinder block, 1a: water jacket, 2: gasket, 3: cylinder bed,
6: Subchamber (vortex chamber), 11: Subchamber insert, 1
3: Gasket body, 14: Grommet, 15:
Through hole, 16: water passage.

Claims (1)

[Claims for Utility Model Registration] A cylinder head having a subchamber is mounted and fixed on a cylinder block equipped with a water jacket via a gasket, and the subchamber is defined by a subchamber insert attached to the cylinder head. , in a diesel engine configured such that a portion of the pre-chamber insert abuts the gasket, the gasket comprising: a gasket body having a through hole provided near the bottom of the pre-chamber insert; and a cylinder head of the gasket body. a heat exchanger plate attached to a side surface, closing the opening of the through hole and abutting the bottom of the subchamber insert; A pre-chamber type diesel engine characterized by having a communicating water passage.