JPS62282112A - Internal combustion engine - Google Patents

Abstract

PURPOSE:To make the opening sectional area of a nozzle hole variable by rotatably mounting a sub-combustion chamber member spherically formed of ceramic material on a cylinder head. CONSTITUTION:In a sub-combustion chamber member 5, a rotating shaft 10 in the sub-combustion chamber is externally rotated according to an engine load and the number of its revolutions to make a communicating hole 12 formed on the bottom of a seat 8 properly mask a nozzle hole li and thereby variably control its opening sectional area. For instance, the opening sectional area of the nozzle hole 11 is minimized under the condition of low revolutions and low load to realize the safety of combustion and excellent startability during the low revolution of the engine. Under the condition of the partial loading of the engine, the opening sectional area of the nozzle hole 11 is made narrower, and in the case of the full loading of the engine, since a large quantity of air is required to be drawn in to maximize the quantity of air flowing into a cylinder, the opening sectional area of the nozzle hole 11 is maximized. Therefore, the optimum condition of engine combustion can be realized according to an engine condition.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an internal combustion engine such as a diesel engine.

[Conventional technology]

Conventionally, diesel engines, which are a type of internal combustion engine, have two combustion methods: a direct injection method, in which fuel is directly injected into a single main combustion chamber for combustion, and a vortex chamber is provided in addition to the main combustion chamber. There is a sub-combustion chamber type in which an injection port is opened on the inner wall of the chamber, and fuel is injected from a fuel injection nozzle into the swirl chamber via the injection boat for temporary combustion. However, in recent years, diesel engines have become smaller and faster, and as a result of the need to complete combustion in a shorter period of time, auxiliary combustion chamber systems, which are capable of high-speed combustion and produce less noise, have become widely used. .

The sub-combustion chamber in such a diesel engine usually has a lower half of the sub-combustion chamber in which a through-hole called a nozzle hole communicating with the main combustion chamber is provided in the cylinder head which is equipped with a cooling water passage above the main combustion chamber. A metal hot plug is installed.

As diesel engines become smaller and faster, the real plugs installed in this way are equipped with turbochargers, and are made of high-grade heat-resistant alloys made of nickel, cobalt, etc. for their heat resistance and insulation properties. Despite this, its durability was poor. In addition, since the sub-combustion chamber is made of metal, it has good thermal conductivity, so the heat from the hot plug is conducted to the cylinder head which is cooled by cooling water, and the temperature of the hot plug itself does not rise, resulting in sub-combustion. The combustion gas inside the room is cooled by the wall surface, and the warm-up characteristics at the initial stage of engine startup are extremely poor, causing misfires to occur easily.In addition to generating unburned gas from ICs, etc., combustion in the main combustion chamber does not occur. It has the disadvantage that it tends to produce smoke when not properly harvested, and it also has the disadvantage that it is expensive to harvest.

Therefore, with the increase in heat load due to higher performance as mentioned above,
The vortex chamber, which is at the highest temperature, is made of ceramic materials with high heat resistance (such as silicon nitride, sialon, silicon carbide, zirconia, and lithia, which are inexpensive and have excellent heat insulation properties). The proposed method is to promote the atomization of fuel in the ta'tA chamber by utilizing the characteristics of the fuel, particularly to improve the ignitability of the air-fuel mixture and its combustion, and to reduce the amount of particulate emissions in the exhaust gas. has been done.

In addition, in order to improve the startability and stability of combustion at low rotation speeds, a heating element is disposed in part or all of the sub-combustion chamber.
It has been proposed to control combustion.

Furthermore, in order to improve the combustion state, a three-way catalyst is supported on the inner surface of the sub-combustion chamber to remove HC, which is a harmful substance.

It has also been proposed to reduce the amount of CO, No, etc. generated.

[Problem that the invention seeks to solve]

However, in the case where the swirl chamber is made of ceramic material, many attempts have been made to improve the cross-sectional shape of the nozzle hole in order to improve combustion as well as to obtain the heat insulating effect of the ceramic material. With the nozzle hole cross-sectional shape, it is difficult to improve combustion over all combustion regions in the complex combustion situation of diesel engines, and the intended purpose could not be achieved.

In addition, when a glow plug is installed as a heating element in the auxiliary combustion chamber, it is desirable for the fuel to hit the glow plug in order to better achieve the effects of improving startability and improving combustion stability at low rotation speeds. Therefore, it is necessary to make the glow plug protrude into the auxiliary combustion chamber, counterbore a part of the wall of the auxiliary combustion chamber,
It is necessary to arrange the glow plug so that part or all of it is located in the counterbore, and the natural flow of the vortex will be disturbed and the flame propagation will be hindered and the combustion conditions will deteriorate except during startup and low rotation. There is a problem that smoke is likely to be generated (which can also be a major factor in reducing output), and it is technically difficult to place a heating element in part or all of the interior of the auxiliary combustion chamber to control combustion. It was extremely difficult.

Furthermore, in the case where the three-way catalyst is supported on the inner surface of the sub-combustion chamber, there is a problem that the durability of the catalyst is poor.

[Means for solving problems]

In view of the above, the present invention aims to optimize the amount of air flowing into the sub-combustion chamber and the strength of the vortex flow, thereby providing a high-output, low-pollution internal combustion engine. It is characterized in that it constitutes a combustion chamber member and is rotatably supported, and that the opening cross-sectional area of the nozzle hole provided in the sub-combustion chamber can be varied.

〔Example〕

Hereinafter, embodiments of the present invention will be specifically described in detail with reference to the drawings.

In the internal combustion engine E shown in FIG. 1, a piston 1 forms a main combustion chamber 2, a cylinder head 3 is equipped with a cooling channel 4 and a sub-combustion chamber member 5 made of the ceramic material, and an injection port 6 is equipped with a fuel injection nozzle 7. This sub-combustion chamber member 5 is made of ceramic material such as silicon nitride or Sialon, and because these ceramics have excellent high-temperature strength and high-temperature lubrication-free sliding properties, the outer shape is spherical, and the concave spherical surface 8a The auxiliary combustion chamber rotating shaft 10 is fixed to the auxiliary combustion chamber member 5 and is slidably supported by the sheets 8 and 9 made of the ceramic material having the above-mentioned properties.

On the other hand, the auxiliary combustion chamber rotating shaft 10 fixed to the auxiliary combustion chamber member 5
By rotating the nozzle hole 11 from the outside, the cross-sectional area of the nozzle hole 11 is variably controlled by appropriately shielding the nozzle hole 11 formed in the sub-combustion chamber member 5 with the communication hole 12 formed on the bottom surface of the seat 8. .

In addition, a cushion ring 13 having a C-shaped or S-shaped cross section is interposed between the sheets 8 and 9 to provide sealing and cushioning properties, and is sandwiched between the sheets 8 and 9 so as to slide. The freely supported auxiliary combustion chamber member 5 is fitted with a seal ring 14 so as not to impair the heat insulating effect of the ceramic material.
The cylinder head 3 is attached to the cylinder block 1 via the head gasket [15].
6 and the engine is assembled.

In the sub-combustion chamber member 5 for an internal combustion engine configured as described above, the amount of air flowing into the sub-combustion chamber member 5 and the strength of the vortex of high-pressure air in the vortex chamber 5a are controlled. In order to control the combustion gas flowing into the chamber 2, the auxiliary combustion chamber rotating shaft 10 is rotated from the outside in response to the load and rotation speed of the engine, and the nozzle hole 11 is connected to a communication hole formed in the bottom surface of the seat 8. 1
2, the opening cross-sectional area of the nozzle hole 12 is variably controlled by appropriately shielding the nozzle hole 12. For example, in a low rotation and no-load state, the opening cross-sectional area of the nozzle hole 11 is minimized as shown in FIG. Stable combustion and good startability at low speeds are achieved.

In addition, when the engine is under partial load, the opening cross-sectional area of the nozzle hole 11 becomes smaller as shown in FIG.
When the engine is under full load, a large amount of air must be allowed to flow in as shown in FIG. 4, so by maximizing the cross-sectional area of the nozzle holes 12, an optimal combustion state can be achieved depending on the engine situation.

〔Effect of the invention〕

As described above, according to the internal combustion engine according to the present invention, the opening cross-sectional area of the nozzle hole can be variably controlled in response to the load and rotation speed of the engine. It is possible to generate an appropriate premixed air by mixing the air, greatly improving the air utilization rate, and achieving optimal combustion, which suppresses smoke generation and, in turn, significantly reduces the amount of particulate emissions in the exhaust gas. This improves combustion efficiency and reduces power loss, and also reduces noise and heat load by shortening the ignition delay time.As a result, the maximum combustion temperature decreases, reducing NOK, a harmful substance. This makes it possible to reduce the amount of gas generated, and to obtain a high-output, low-pollution internal combustion engine.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of main parts showing the structure of an internal combustion engine according to an embodiment of the present invention, and FIGS. FIG. 3 is a bottom view of a main part for explaining the opening state of a hole. l...Piston 2...Main combustion chamber 3...Cylinder head 4...Cooling channel 5...Sub-combustion chamber member 5a...Swirl chamber 6...Injection port 7...Fuel injection Nozzle 8...Seat 9...Seat 10...Sub-combustion chamber rotating shaft 11...Nozzle hole 12...Communication hole 13...Kungjong ring 14...Seal ring 15...Head Gasket 16...Cylinder block

Claims (1)

[Claims] An auxiliary combustion chamber member having a nozzle hole communicating with the main combustion chamber of the engine is formed into a spherical shape using a ceramic material and is rotatably attached to the cylinder head, so that the opening cross-sectional area of the nozzle hole can be varied. An internal combustion engine characterized by: