JPH0771310A - Internal combustion engine provided with auxiliary chamber - Google Patents

Abstract

PURPOSE:To improve the heat resistance of the nozzle hole part of an internal combustion engine provided with an auxiliary chamber without using a material of high heat resistance, which is expensive, or which is difficult to machine. CONSTITUTION:A cooling system is arranged so that the cylinder wall 2a of the surroundings of a main combustion chamber consisting of a part of a cylinder head 1 or a cylinder block 2 is cooled well, and the nozzle hole 8 of an auxiliary chamber is provided on the cooling system, while the main body part of the auxiliary chamber is formed independently from the cylinder head 1 or the cylinder block 2, and is fitted or cast into the cylinder head 1 or the cylinder block 2. The auxiliary chamber is arranged in the center of the combustion chamber, while an inlet mask wall is provided along the opening part in the bore center of an inlet valve, and most of the inlet air flows downward along the cylinder wall 2a and little air flows in the bore center side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine with a sub chamber, and more particularly to a structure of a swirl chamber type internal combustion engine with a sub chamber.

[0002]

2. Description of the Related Art In an internal combustion engine with a sub-chamber, fuel injected into the sub-chamber is self-ignited and combustion gas is ejected through a nozzle into a main combustion chamber on the top surface of a piston. In the internal combustion engine with a sub chamber, the method of integrally forming the main body of the swirl chamber inside the cylinder head, disposing the separately formed lower chamber at the bottom of the swirl chamber, and providing the injection port there is adopted. (See Figure 4).

[0003]

By the way, in the internal combustion engine with the auxiliary chamber, the fuel injected into the auxiliary chamber as described above is self-ignited, and the combustion gas is injected into the main combustion chamber on the top surface of the piston through the injection port. However, it is preferable that the main body of the sub-chamber is better insulated and kept warm to improve the ignitability.On the other hand, the heat resistance of the injection port is high because the high temperature combustion gas passes through the narrow passage. On the contrary, it is preferable to improve the cooling because the temperature becomes so high as to affect the durability. However, in the above-mentioned conventional method, the main body of the sub-chamber, which should be well insulated and kept warm, is cooled relatively well because the cooling water directly hits the back side of the wall forming the sub-chamber. Since it is provided in a lower chamber that is formed separately and does not come into direct contact with cooling water, cooling is not good.Therefore, the lower chamber in which the nozzle is installed is made of a heat-resistant alloy with excellent heat resistance, or ceramic, etc. By improving the heat resistance, the resistance to high temperature is increased. However, heat-resistant alloys and ceramics are expensive and difficult to process. In view of the above problems, the present invention provides an internal combustion engine with a sub chamber in which the heat resistance of the injection port portion of the internal combustion engine with a sub chamber is improved without using an expensive or difficultly heat-resistant material having high heat resistance. With the goal.

[0004]

According to the present invention, a cooling system is arranged so that a cylinder wall around a main combustion chamber, which is formed of a part of a cylinder head or a cylinder block, is well cooled, and is cooled well. The cooling system is arranged so that
There is provided an internal combustion engine with an auxiliary chamber, characterized in that an injection port of the auxiliary chamber is provided in a cylinder wall around a main combustion chamber, which is composed of a part of a cylinder head or a cylinder block. Also,
The entire lower wall of the sub chamber may be integrated with the cylinder wall around the main combustion chamber, which is formed of a part of the cylinder head or the cylinder block, and the peripheral walls other than the lower wall may be formed of a member different from the cylinder head or the cylinder block. Further, the auxiliary chamber is arranged at the center of the combustion chamber, and the intake mask wall is provided along the opening on the center side of the bore of the intake valve so that almost all of the intake air flows downward along the cylinder wall. It is also possible to prevent almost no flow into the bore center side.

[0005]

Since the cylinder wall around the main combustion chamber is well cooled, the injection port does not overheat even if the injection port of the auxiliary chamber is provided there. Further, if the entire lower wall of the sub chamber is integrated with the cylinder wall around the main combustion chamber consisting of a part of the cylinder head or the cylinder block, and the peripheral walls other than the lower wall are formed by a member different from the cylinder head or the cylinder block, Since the main body of the sub chamber is insulated and kept warm, the ignitability is improved. Further, the auxiliary chamber is arranged at the center of the combustion chamber, and the intake mask wall is provided along the opening on the center side of the bore of the intake valve so that almost all of the intake air flows downward along the cylinder wall. , Cooling the sub-chamber part if it hardly flows into the bore center side,
The heating cycle is relaxed and the heat resistance of the sub chamber is improved.

[0006]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a view showing the structure of a first embodiment of an internal combustion engine with a swirl chamber type auxiliary chamber according to the present invention, in which 1 is a cylinder head part and 2 is a cylinder block part.
As is apparent from the figure, the engine of this embodiment is a so-called monoblock structure engine in which the cylinder head portion 1 and the cylinder block portion 2 are integrated. 2a is a cylinder liner wall, 3a is a cooling water passage for cooling the cylinder liner wall 2a, and communicates with a cooling water passage 3b provided above the combustion chamber upper wall 4. Reference numeral 5 denotes a sub chamber member, which is press-fitted into a recess provided in the cylinder head portion 1 and fixed by a plug 6. 7 is a sub chamber member 5
Of the vortex chamber, the bottom of which is opened and communicates with a main combustion chamber (not shown) formed above the piston 9 by an injection port 8 provided in the combustion chamber upper wall 4. There is. Reference numeral 10 is a fuel injection valve, and 11 is a glow plug.

Cooling around the combustion chamber of an internal combustion engine with a swirl chamber type sub-chamber having a monoblock structure configured as described above will be further compared with a conventional engine having a structure in which a cylinder head portion and a cylinder block portion are divided. Detailed description. The cooling water passage of an internal combustion engine can be roughly divided into a cylinder head portion and a cylinder block portion. Among them, the cooling water passage of the cylinder block portion is relatively large even in an engine having a structure in which a conventional cylinder head portion and cylinder block portion are divided. It can be formed freely and is arranged so that the cooling water flows smoothly, but the cooling water passage of the cylinder head part is
In addition to the intake port wall, the intake port wall, the fuel injection valve mounting boss, the swirl chamber wall, etc., in the conventional engine having a structure in which the cylinder head part and the cylinder block part are divided,
Furthermore, since it is formed while avoiding bosses for passing many head bolts for fastening the cylinder head part and the cylinder block part, there is almost no freedom and the flow of cooling water is not smooth, and the upper wall of the combustion chamber is cooled. Is not always enough.

Further, in the conventional engine having a structure in which the cylinder head portion and the cylinder block portion are divided, a head gasket is provided between the cylinder head portion and the cylinder block portion, and the cylinder head portion is provided on the head gasket. It is necessary to provide a hole for communicating the cooling water passage with the cooling water passage of the cylinder block part, but a very large hole cannot be provided to maintain the strength of the head gasket, and the cooling water flow is throttled here. Sometimes.

On the other hand, in the engine having the monoblock structure as in this embodiment, the flow of the cooling water in the cylinder head portion is improved because the cylinder head portion has no boss for passing the head bolt. In addition, since there is no head gasket, the flow of the entire cooling water is improved, so that the upper wall of the combustion chamber is sufficiently cooled. Therefore, it is possible to avoid the temperature from becoming excessively high even if a high temperature combustion gas passes through the injection port provided in the upper wall of the combustion chamber and is heated.

On the other hand, the periphery of the swirl chamber should be insulated and kept warm in order to improve the ignitability, but in the conventional structure, the flow is not smooth because it is formed integrally with the cylinder head. However, the upper wall of the swirl chamber is directly cooled by the cooling water, which is not preferable. On the other hand, in this embodiment, the swirl chamber main body is provided inside the auxiliary chamber member 5 formed separately. Since it is press-fitted into the concave portion provided in the cylinder head, the swirl chamber is not directly cooled by the cooling water, so that the swirl chamber 7 is better insulated and kept warm, and the ignition property is improved.

FIG. 2 is a view showing the structure of the second embodiment of the present invention, in which a swirl chamber type auxiliary chamber is formed in the center of the upper portion of the main combustion chamber and is formed as a separate chamber. The member 5 is cast into the cylinder head portion 1 above the center of the main combustion chamber. Therefore, the sub chamber member 5 is downsized as compared with the case of the first embodiment, and the fixing plug is unnecessary.

FIG. 3 is a view showing the structure of an embodiment of an internal combustion engine with a swirl chamber type auxiliary chamber according to claim 3 of the present invention. Although the swirl chamber type auxiliary chamber is not shown, it is the same as in FIG. It is located in the center of the upper wall of the combustion chamber. Reference numeral 12 is an intake port, 13 is an intake valve, and 14 is an intake mask wall for diverting the flow of fresh air introduced from the intake port 12 when it is introduced into the main combustion chamber when the intake valve 13 is opened. 15 is an exhaust valve, 1
6 is an exhaust port.

When the intake valve 13 is opened and fresh air is introduced into the main combustion chamber, the valve opening area on the center side of the bore is changed to the intake mask wall 14.
Because of the smaller opening area on the outer peripheral side of the bore, the flow of the scavenging flow is biased downward toward the outer peripheral side of the bore as indicated by arrow 17, and flows to the outer peripheral side of the opposite side on the upper surface of the piston 9. Flows towards the exhaust valve along the opposite bore circumference. As a result, since the substantially central portion of the bore is difficult to be scavenged, a relatively high temperature gas is likely to remain, and the temperature change between the scavenging stroke and the combustion stroke is smaller than that in the peripheral portion of the bore. Therefore, by providing the sub chamber substantially in the center of the bore, the temperature change of the sub chamber, that is, the cold cycle change that is cooled by the fresh air and heated by the combustion gas is suppressed, and the durability of the sub chamber is improved.

On the contrary, when the sub chamber is provided on the outer peripheral portion of the bore on the intake port side, when the intake valve opens and fresh air having a relatively low temperature flows in, the surrounding area of the intake valve is cooled by the fresh air, Accordingly, the sub chamber is also cooled. On the other hand, in the combustion process, the sub chamber is heated to a high temperature by the high temperature combustion gas. Therefore, the sub chamber is repeatedly cooled and heated, which is not preferable in terms of durability.

In the above description of the embodiments for each claim of the present invention, all of which are based on the engine of the monoblock structure, but the cylinder wall around the main combustion chamber in which the injection port is provided is sufficiently cooled. For example, the structure is not particularly limited to a monoblock structure, and a structure in which the cylinder head portion and the cylinder block portion are divided as in the conventional case may be used.

[0016]

Since the present invention is constructed and operates as described above, the injection port portion of the sub chamber is arranged in the cylinder wall portion around the main combustion chamber, which is composed of a part of the cylinder head or cylinder block having a good cooling property. Since it is not necessary to use a heat-resistant alloy or ceramic that is expensive or difficult to process, if the main body of the sub-chamber is made as a separate body, it is insulated and kept warm, so that the ignitability is improved. Further, if the sub chamber is provided at the center of the bore, the sub chamber member can be downsized, and the plug for fixing the sub chamber member can be eliminated. further,
If the sub chamber is provided in the center of the bore and the intake mask wall is provided on the bore center side of the opening of the intake valve to prevent the flow of scavenging air from passing through the center of the bore too much, the change in the thermal cycle near the sub chamber can be suppressed. The durability of the sub chamber member is improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing a structure of a first embodiment of the present invention.

FIG. 2 is a sectional view showing the structure of the second embodiment of the present invention.

FIG. 3 is a sectional view showing a structure of a third embodiment corresponding to the third claim of the present invention.

FIG. 4 is a sectional view of an internal combustion engine with a sub chamber having a conventional sub chamber structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Cylinder head part 2 ... Cylinder block part 2a ... Cylinder liner wall 3a ... Cooling water passage 3b ... Cooling water passage 4 ... Combustion chamber upper wall 5 ... Sub chamber member 6 ... Plug 7 ... Vortex chamber 8 ... Jet port 9 ... Piston 10 ... Fuel injection valve 11 ... Glow plug 12 ... Intake port 13 ... Intake valve 14 ... Intake mask wall 15 ... Exhaust valve 16 ... Exhaust port 17 ... Scavenging flow 18 ... Lower chamber

Claims (3)

[Claims] 1. A cooling system is arranged so that a cylinder wall around a main combustion chamber, which is composed of a part of a cylinder head or a cylinder block, is well cooled, and a cooling system is arranged so as to be well cooled. An internal combustion engine with a sub-chamber, characterized in that a sub-chamber injection port is provided in a cylinder wall around a main combustion chamber, which is composed of a part of a cylinder head or a cylinder block. 2. The entire lower wall of the auxiliary chamber is integrated with a cylinder wall around the main combustion chamber, which is a part of a cylinder head or a cylinder block, and the peripheral walls other than the lower wall are made of a member different from the cylinder head or the cylinder block. The internal combustion engine with a subchamber according to claim 1, wherein the internal combustion engine has a subchamber. 3. The auxiliary chamber is arranged in the center of the combustion chamber, and
An intake mask wall is provided along the opening on the center side of the bore of the intake valve so that almost all of the sucked air is allowed to flow downward along the cylinder wall and hardly flow to the center side of the bore. The internal combustion engine with a sub chamber according to claim 1, wherein the internal combustion engine has a sub chamber.